Littérature scientifique sur le sujet « Group Activity Selection »
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Articles de revues sur le sujet "Group Activity Selection"
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Darmann, Andreas, Edith Elkind, Sascha Kurz, Jérôme Lang, Joachim Schauer et Gerhard Woeginger. « Group activity selection problem with approval preferences ». International Journal of Game Theory 47, no 3 (14 octobre 2017) : 767–96. http://dx.doi.org/10.1007/s00182-017-0596-4.
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Darmann, Andreas. « Manipulability in a group activity selection problem ». Social Choice and Welfare 52, no 3 (13 octobre 2018) : 527–57. http://dx.doi.org/10.1007/s00355-018-1155-z.
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Darmann, Andreas. « A social choice approach to ordinal group activity selection ». Mathematical Social Sciences 93 (mai 2018) : 57–66. http://dx.doi.org/10.1016/j.mathsocsci.2018.01.005.
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Darmann, Andreas. « Stable and Pareto optimal group activity selection from ordinal preferences ». International Journal of Game Theory 47, no 4 (3 février 2018) : 1183–209. http://dx.doi.org/10.1007/s00182-018-0612-3.
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Banos, Oresti, Miguel Damas, Hector Pomares, Alberto Prieto et Ignacio Rojas. « Daily living activity recognition based on statistical feature quality group selection ». Expert Systems with Applications 39, no 9 (juillet 2012) : 8013–21. http://dx.doi.org/10.1016/j.eswa.2012.01.164.
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Carter, Cindy L., Georgiana Onicescu, Kathleen B. Cartmell, Katherine R. Sterba, James Tomsic, Todd Fox, Erica Dunmeyer et Anthony J. Alberg. « Factors associated with cancer survivors’ selection between two group physical activity programs ». Journal of Cancer Survivorship 4, no 4 (27 juillet 2010) : 388–98. http://dx.doi.org/10.1007/s11764-010-0142-x.
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Yu, Na, Yongjian Zhao, Qi Han, Weiping Zhu et Hejun Wu. « Identification of Partitions in a Homogeneous Activity Group Using Mobile Devices ». Mobile Information Systems 2016 (2016) : 1–14. http://dx.doi.org/10.1155/2016/3545327.
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People in public areas often appear in groups. People with homogeneous coarse-grained activities may be further divided into subgroups depending on more fine-grained behavioral differences. Automatically identifying these subgroups can benefit a variety of applications for group members. In this work, we focus on identifying such subgroups in a homogeneous activity group (i.e., a group of people who perform the same coarse-grained activity at the same time). We present a generic framework using sensors built in commodity mobile devices. Specifically, we propose a two-stage process, sensing modality selection given a coarse-grained activity, followed by multimodal clustering to identify subgroups. We develop one early fusion and one late fusion multimodal clustering algorithm. We evaluate our approaches using multiple datasets; two of them are with the same activity while the other has a different activity. The evaluation results show that the proposed multimodal-based approaches outperform existing work that uses only one single sensing modality and they also work in scenarios when manually selecting one sensing modality fails.
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Pérez-Domínguez, Luis, Alejandro Alvarado-Iniesta, Iván Rodríguez-Borbón et Osslan Vergara-Villegas. « Intuitionistic Fuzzy MOORA for Supplier Selection ». DYNA 82, no 191 (22 juin 2015) : 34–41. http://dx.doi.org/10.15446/dyna.v82n191.51143.
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<p class="ADYNAAbstrac"><span lang="EN-US">The supplier selection is a critical activity within the administration of the supply chain. It is considered a complex problem given that it involves different aspects such as the alternatives to evaluate, the multiple criteria involved as well as the group of decision makers with different opinions. In this sense, the literature reports several methods to help in this difficult activity of selecting the best supplier. However, there are still some gaps in these methods; therefore, it is imperative to further develop research. Thus, the purpose of this paper is to report a hybrid method between MOORA and intuitionistic fuzzy sets for the selection of suppliers with a focus on multi-criteria and multi-group environment. The importance of decision makers, criteria and alternatives are evaluated in terms of intuitionistic fuzzy sets. Then, MOORA is used in order to determine the best supplier. An experimental case is developed in order to explain the proposed method in detail and to demonstrate its practicality and effectiveness.</span></p>
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Song, Yeo-Jin, Soo-Kyung Cho, Hyoungyoung Kim, Hye Won Kim, Eunwoo Nam, Chan-Bum Choi, Tae-Hwan Kim et al. « Factors associated with selection of targeted therapy in patients with rheumatoid arthritis ». PLOS ONE 18, no 1 (10 janvier 2023) : e0280234. http://dx.doi.org/10.1371/journal.pone.0280234.
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Objective Deciding which drug to choose for targeted therapy is an important step in sequential treatment for rheumatoid arthritis (RA). This study aimed to identify factors for selecting Janus kinase inhibitors (JAKis) rather than biologic disease-modifying antirheumatic drugs (bDMARDs) in patients with RA in real-world practice. Methods We selected RA patients starting JAKis or bDMARDs from single-center prospective cohorts in Korea. Patients were divided into JAKi, tumor necrosis factor (TNF) inhibitor, and non-TNF inhibitor groups. We performed multinomial logistic regression analyses to identify factors associated with selecting JAKis. Results 145, 205, and 89 patients were included in the JAKi, TNF inhibitor, and non-TNF inhibitor groups. In multinomial regression analysis, the JAKi group was older than the TNF inhibitor group (OR 1.03, 95% confidence interval [CI] 1.01–1.05) but younger than the non-TNF inhibitor group (OR 0.97, CI 0.95–1.00). The JAKi group was less likely to have chronic pulmonary diseases compared with the TNF inhibitor group (OR 0.07, CI 0.01–0.56) or the non-TNF inhibitor group (OR 0.06, CI 0.01–0.50). Higher disease activity assessed by physician (OR 1.80, CI 1.51–2.38) and previous tacrolimus use (OR 2.05, CI 1.20–3.51) were factors suggesting selection of JAKis than TNF inhibitors. Conclusion Age, pulmonary comorbidities, previous tacrolimus use, and high disease activity assessed by physician were factors influencing the selection of JAKis for RA patients in Korea.
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Lima, Edson de Souza, Karen E. DeMatteo, Rodrigo S. P. Jorge, Maria Luisa S. P. Jorge, Julio Cesar Dalponte, Herson Souza Lima et Stuart A. Klorfine. « First telemetry study of bush dogs : home range, activity and habitat selection ». Wildlife Research 39, no 6 (2012) : 512. http://dx.doi.org/10.1071/wr11176.
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Context The bush dog (Speothos venaticus) is difficult to observe, capture, and study. To date, indirect evidence and opportunistic field observations have been the primary sources of information about the species’ ecology. Field data are urgently needed to clarify the species’ ecological requirements, behaviour and movement patterns. Aims The present study uses 13 months of telemetry data from a group of bush dogs to begin to address questions about area requirements, habitat preferences and movement patterns of this difficult-to-study species. Methods We tracked a group of bush dogs (two adults, one juvenile, four young) in an area of intact and altered Cerrado (woodland–savanna biome) in eastern Mato Grosso, Brazil (Nova Xavantina District). Key results The group had a total home range of 140 km2 (fixed kernel 95%), with smaller seasonal ‘subareas’ (areas used for 1–2 months before moving to another area, with repetition of some areas over time) and demonstrated a preference for native habitats. Conclusions The bush dog’s home range is greater than that of other canids of the same size, even correcting for group size. Patterns of seasonal movement are also different from what has been observed in other South American canids. Implications From our observations in the Brazilian savanna, bush dogs need large tracks of native habitat for their long-term persistence. Although the present study is based on a single pack, it is highly relevant for bush dog conservation because it provides novel information on the species’ spatial requirements and habitat preferences.
Thèses sur le sujet "Group Activity Selection"
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Keller, Merlin. « Selection of a model of cerebral activity for fMRI Group Data analysis ». Paris 11, 2010. http://www.theses.fr/2010PA112045.
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L’imagerie par résonance magnétique fonctionnelle (IRMf ) permet d’acquérir des images tridimensionnelles de l’activité cérébrale d’un sujet soumis à une séquence de stimulations sensorielles. L’analyse statistique des ces données permet de détecter les aires cérébrales actives en réponse aux différentes stimulations. Lorsque plusieurs sujets ont été recrutés pour une expérience, l’analyse de groupe consiste à généraliser les résultats individuels à la population d’intérêt dont sont issus les sujets. La variabilité morphologique du cerveau humain rend cependant la comparaison des images acquises sur les différents sujets problématique. L’approche usuelle pour contrer cette difficulté consiste à recaler les sujets dans un Référentiel commun, puis de comparer les cerveau séparément en chaque point de ce référentiel. Cette étape de recalage n’ étant jamais parfaite, il en résulte une incertitude sur la localisation spatiale de chaque sujet. Nous proposons dans un premier temps d’ étendre le modèle classique d’analyse de groupe afin de prendre en compte cette incertitude spatiale. Dans un deuxième temps, nous développons à partir de ce modèle une nouvelle approche de détection d’aires cérébrales actives, basée sur des régions d’intérêt prédéfinies plutôt que sur les procédures de seuillage couramment utiliséesThis thesis is dedicated to the statistical analysis of multi-sub ject fMRI data, with the purpose of identifying bain structures involved in certain cognitive or sensori-motor tasks, in a reproducible way across sub jects. To overcome certain limitations of standard voxel-based testing methods, as implemented in the Statistical Parametric Mapping (SPM) software, we introduce a Bayesian model selection approach to this problem, meaning that the most probable model of cerebral activity given the data is selected from a pre-defined collection of possible models. Based on a parcellation of the brain volume into functionally homogeneous regions, each model corresponds to a partition of the regions into those involved in the task under study and those inactive. This allows to incorporate prior information, and avoids the dependence of the SPM-like approach on an arbitrary threshold, called the clusterforming threshold, to define active regions. By controlling a Bayesian risk, our approach balances false positive and false negative risk control. Urthermore, it is based on a generative model that accounts for the spatial uncertainty on the localization of individual effects, due to spatial normalization errors. On both simulated and real fMRI datasets, we show that this new paradigm corrects several biases of the SPM-like approach, which either swells or misses the different active regions, depending on the choice of a cluster-forming threshold
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VARRICCHIO, GIOVANNA. « Gathering Self-Interested People Together : a Strategic Perspective ». Doctoral thesis, Gran Sasso Science Institute, 2021. http://hdl.handle.net/20.500.12571/23261.
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Over the past decades, the understanding of how individuals spontaneously gather together received particular attention leading to the definition of several variants of Coalition Formation Games, including the so-called Hedonic Games. In such games, the individuals (or agents) have to be split into disjoint coalitions and express preferences only on the coalition they belong to, and not on how the others aggregate. Subsequently, the more general class of the Group Activity Selection Problem, where agents’ preferences depend also on the activity they are performing, has been introduced. In both these classes of games, the study of the existence, the computability, and the efficiency of suitable stability solution concepts as well as the elicitation of agents’ preferences through strategyproof mechanisms have been addressed.
In this work, we consider both the aforementioned research directions. In particular, we put our attention on classes of games in which agents’ preferences are expressed by a utility function and we evaluate the global agents’ satisfaction in a given outcome by means of the utilitarian social welfare. Moreover, we often compare the social welfare of the considered solutions with the social optimum, that is the maximum achievable value of the social welfare.
We first introduce and study a new model in the Hedonic Games setting, called Distance Hedonic Games, and we focus on the computation and the efficiency of Nash stable outcomes, i.e. coalition structures in which no agent can unilaterally improve her gain by deviating to another coalition. We then turn our attention to the design of strategyproof mechanisms for two specific classes of games: namely, Friends and Enemies Games and the Additively Separable Group Activity Selection Problem. In both cases, we measure the performances of the proposed mechanisms by considering their approximation ratio with respect to the social optimum.
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Hendriks, Carolyn Maree, et C. M. Hendriks@uva nl. « Public Deliberation and Interest Organisations : a Study of Responses to Lay Citizen Engagement in Public Policy ». The Australian National University. Research School of Social Sciences, 2004. http://thesis.anu.edu.au./public/adt-ANU20050921.103047.
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This thesis empirically examines how lobby groups and activists respond to innovative forms of public participation. The study centres on processes that foster a particular kind
of deliberative governance including citizens’ juries, consensus conferences and planning cells. These deliberative designs bring together a panel of randomly selected lay citizens
to deliberate on a specific policy issue for a few days, with the aim of providing decision makers with a set of recommendations. While policy makers worldwide are attracted to these novel participatory processes, little consideration has been given to how well they work alongside more adversarial and interest-based politics. This doctoral research project examines this interface by studying what these processes mean to different kinds of policy actors such as corporations, advocacy groups, government agencies, experts
and professionals. These entities are collectively referred to in this thesis as ‘interest organisations’ because in some way they are seeking a specific policy outcome from the
state – even government-based groups.¶
The empirical research in this thesis is based on comparative case studies of four deliberative design projects in Australia and Germany. The Australian cases include a citizens’ jury on waste management legislation and a consensus conference on gene
technology in the food chain. The German case studies include a planning cells project on consumer protection in Bavaria, and a national consensus conference on genetic diagnostics. Together the cases capture a diversity of complex and contested policy
issues facing post-industrialised societies. In each case study, I examine how relevant interest organisations responded to the deliberative forum, and then interpret these responses in view of the context and features of the case.¶
The picture emerging from the in-depth case studies is that interest organisations respond to deliberative designs in a variety of ways. Some choose to participate actively,
others passively decline, and a few resort to strategic tactics to undermine citizens’ deliberations. The empirical research reveals that though responses are variable, most
interest organisations are challenged by several features of the deliberative design model including: 1) that deliberators are citizens with no knowledge or association with the
issue; 2) that experts and interest representatives are required to present their arguments before a citizens’ panel; and 3) that policy discussions occur under deliberative conditions which can expose the illegitimate use of power.¶
Despite these challenges, the paradox is that many interest organisations do decide to engage in lay citizen deliberations. The empirical research indicates that groups and experts value deliberative designs if they present an opportunity for public relations, customer feedback, or advocacy. Moreover, the research finds that when policy actors
intensively engage with ‘ordinary’ citizens, their technocratic and elite ideas about public participation can shift in a more inclusive and deliberative direction.¶
The thesis finds that, on the whole, weaker interest organisations are more willing to engage with lay citizens than stronger organisations because they welcome the chance to influence public debate and decision makers. It appears that powerful groups will only
engage in a deliberative forum under certain policy conditions, for example, when the dominant policy paradigm is unstable and contested, when public discussion on the issue is emerging, when policy networks are interdependent and heterogeneous, and when the broader social and political system supports public accountability, consensus and
deliberation. Given that these kinds of policy conditions do not always exist, I conclude that tensions between interest organisations and deliberative governance will be common. In order to create more cooperative and productive interfaces, I recommend
that interest organisations be better supported and integrated into citizens’ deliberations, and that steps be taken to safeguard forums from strategic attempts to undermine their
legitimacy.¶
The thesis also sends out three key messages to democratic theorists. First, the empirical research shows that different kinds of groups and actors in civil society vary in their
willingness and capacity to participate to public deliberation. Second, the deliberative design model demonstrates that partisan actors, such as interest organisations, will engage in public deliberation when they can participate as strategic deliberators. In this role
partisans are not expected to relinquish their agendas, but present them as testimonies before a group of deliberators. Third, the empirical research in this thesis should bring
home to theorists that deliberative forums are closely linked to the discursive context within which they operate.
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Wu, Chi-Pin, et 吳啟斌. « Seasonal Patterns in Group, Population Composition, Daily Activity Cycle and Habitat Selection of Blue Sheep (Pseudois nayaur) in Helanshan ». Thesis, 2004. http://ndltd.ncl.edu.tw/handle/01408248287300410711.
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碩士國立中山大學
生物科學系研究所
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The blue sheep (Pseudious nayaur) is the major large-size herbivores in Helanshan. During studying, the blue sheep mean group size were 4.2∼7.1, with smaller group size than in other ranges. Mixed groups were usually bigger than male and female groups. Sex ratio the most close was 1:1.08 (♀:♂) in winter, and other samples still favored males except for fall. The highest ratio of adult female to young was 1:0.78 in summer. In daily activity cycle, blue sheep usually moved and fed in morning and evening, but rested during noon. In summer, animals started active earlier and ended latter than in winter, but had more short active time. From summer to fall, the blue sheep mostly used the edge of forest and used forest least in altitude 2200m. But in altitude 1700m, blue sheep used grassland more than frequently bush and fountain.
Livres sur le sujet "Group Activity Selection"
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Division, San Francisco (Calif ). Office of the Controller City Services Auditor. Board of Supervisors : Political activity audit : The Allen Group, LLC. San Francisco : Office of the Controller, 2006.
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San Francisco (Calif.). Office of the Controller. City Services Auditor Division. Board of Supervisors : Political activity audit : Museo ItaloAmericano. San Francisco : Office of the Controller, 2006.
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San Francisco (Calif.). Office of the Controller. City Services Auditor Division. Board of Supervisors : Political activity audit : RISE Institute. San Francisco : Office of the Controller, 2006.
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Division, San Francisco (Calif ). Office of the Controller City Services Auditor. Board of Supervisors : Political activity audit : La Playa Apartments. San Francisco : Office of the Controller, 2006.
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Division, San Francisco (Calif ). Office of the Controller City Services Auditor. Board of Supervisors : Political activity audit : Tigresse Fashion, LLC. San Francisco : Office of the Controller, 2006.
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San Francisco (Calif.). Office of the Controller. City Services Auditor Division. Board of Supervisors : Political activity audit : Ace Legal Assistance. San Francisco : Office of the Controller, 2006.
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San Francisco (Calif.). Office of the Controller. City Services Auditor Division. Board of Supervisors : Political activity audit : Footloose Dance Company, Inc. San Francisco : Office of the Controller, 2006.
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San Francisco (Calif.). Office of the Controller. City Services Auditor Division. Board of Supervisors : Political activity audit : Up From Darkness, Inc. San Francisco : Office of the Controller, 2006.
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Division, San Francisco (Calif ). Office of the Controller City Services Auditor. Board of Supervisors : Political activity audit : HomeBase, The Center for Common Concerns. San Francisco : Office of the Controller, 2006.
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(Editor), Carolyn Nilson, et American Management Association (Corporate Author), dir. The AMA Trainers' Activity Book : A Selection of the Best Learning Exercises from the World's Premiere Training Organization. AMACOM/American Management Association, 2004.
Trouver le texte intégralChapitres de livres sur le sujet "Group Activity Selection"
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Darmann, Andreas, Edith Elkind, Sascha Kurz, Jérôme Lang, Joachim Schauer et Gerhard Woeginger. « Group Activity Selection Problem ». Dans Lecture Notes in Computer Science, 156–69. Berlin, Heidelberg : Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-35311-6_12.
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Darmann, Andreas, Janosch Döcker, Britta Dorn, Jérôme Lang et Sebastian Schneckenburger. « On Simplified Group Activity Selection ». Dans Algorithmic Decision Theory, 255–69. Cham : Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-67504-6_18.
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Darmann, Andreas. « Group Activity Selection from Ordinal Preferences ». Dans Algorithmic Decision Theory, 35–51. Cham : Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-23114-3_3.
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Gupta, Sushmita, Sanjukta Roy, Saket Saurabh et Meirav Zehavi. « Group Activity Selection on Graphs : Parameterized Analysis ». Dans Algorithmic Game Theory, 106–18. Cham : Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-66700-3_9.
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Idrissou, Yaya, Alassan Seidou Assani, Mohamed Nasser Baco et Ibrahim Alkoiret Traoré. « Determinants of Cattle Farmers’ Perception of Climate Change in the Dry and Subhumid Tropical Zones of Benin (West Africa) ». Dans African Handbook of Climate Change Adaptation, 197–212. Cham : Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-45106-6_16.
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AbstractUnderstanding the factors influencing the perception of climate change can help improve policies for strengthening the adaptive capacity of pastoralists with regard to climate change. Despite this importance, few studies have focused on this issue, especially among cattle farmers. In order to attempt filling this gap, this study analyzed the determinants of the perception of climate change by cattle farmers distributed in the dry and sub-humid tropical zones of Benin as well as the current adaptation strategies developed by these farmers. For this purpose, surveys were carried out through group discussions and an individual questionnaire administered to 360 cattle farmers in the two climatic zones. The data collected related to the sociodemographic characteristics of cattle farmers and their perception of climate change and adaptation strategies. A binary logit model has identified the factors that influence cattle farmers’ perceptions of climate change. The results of the study showed that cattle farmers perceive a drop in rain (at least 77%), an increase in temperature (at least 80%), and violent winds (at least 60%). Breeding experience, level of education of the farmer, household size, membership of a breeders’ organization, and cattle herd size determine these perceptions. Four major groups of adaptation strategies have been developed by farmers to cope with climate change. These are production adjustment strategies, activity diversification strategies, livestock management strategies, and selection strategies. The political implication of this study is that government and development partners should integrate these factors into projects and programs related to climate change.
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Moor, Irene, Laura Hoffmann, Martin Mlinarić et Matthias Richter. « Social Networks, Health, and Health Inequalities in Youth ». Dans Social Networks and Health Inequalities, 129–51. Cham : Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-97722-1_8.
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AbstractSince 1960s school-based surveys also focused on social networks of young people. In comparison with other life stages, the evidence regarding social network research is more advanced for school-aged children. These studies identified that homophile of peer groups in adolescence can be attributed to two mechanisms: the thesis of social influence (young people adapt to health and health behaviour of their friends) and the thesis of selection (adolescents choose their friends according to whether they show the same attitudes and (health) behavior as they do themselves). The existing studies focused especially on substance use (smoking and drinking) but also on physical activity and nutrition and to a lesser extent also on mental health, where both these are relevant. However, for explaining health inequalities the evidence is scarce. This chapter will give an overview of social network research on young people and will give insights into the few existing studies regarding the explanation of health inequalities in adolescence (especially regarding smoking). It will also emphasize the need for further research in explaining health inequalities (beyond tobacco consumption) as well as longitudinal research designs.
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Erdoğan, Armağan, et M. Murat Erdoğan. « Syrian University Students in Turkish Higher Education : Immediate Vulnerabilities, Future Challenges for the European Higher Education Area ». Dans European Higher Education Area : Challenges for a New Decade, 229–52. Cham : Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-56316-5_16.
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Abstract Since 2011, millions of Syrian people have had to leave their country and seek shelter in neighbouring countries and in Europe. Forced migration or displacement creates multiple vulnerabilities while trying to settle in a new environment. Socioeconomic, cultural and psychological vulnerabilities hinder them from participating actively in society. Higher education is one of the main ways that refugees and displaced people cling to hope for a better life. Their access to and participation in higher education has been a challenging route for many reasons both for themselves and also for the higher education systems and universities in their host countries. Turkey has a unique place in regard to Syrian refugees. It hosts the largest refugee population in the world with 3.6 million Syrians and 500,000 asylum seekers from other countries, such as Iraq, Iran, Afghanistan and Pakistan. Turkey has a young population with the 5–17 age group comprising 21% of the population, but the Syrian population is much younger as its rate is 30%. Turkey is also the country with the largest student population in the European Higher Education Area. The incomparable magnitude of the situation, among others, plays a crucial role in developing new integration policies. In spite of the ongoing difficulties and challenges, the past nine years proved a success story in protection, social cohesion and integration of these newcomers. Turkey has been suffering from some challenges, such as a supply and demand imbalance in higher education. Demographic factors, shortcomings of the higher education system and the unemployment rate among university graduates have been some long-term challenges for Turkish higher education. Moreover, a common misconception in public opinion, that Syrian refugees are admitted to Turkish universities without fulfilling the requirements, adds new challenges for future policies. Both the sheer number of migrants and also the emergency of the situation during this migration flow necessitated some action to be taken in the area of higher education. In a country like Turkey, where there is high competition between students to pass the nationwide university selection exam each year, encouraging Syrian students to access higher education seems to be an area for discussion. This paper is based on the fieldwork of research conducted in the context of the Hopes-MADAD project entitled “Elite Dialogue II- Dialogue with Syrian Refugees in Turkey through Syrian Academics and Students” in 2019. The main research subject is which types of vulnerabilities Syrian university students face, and how they can integrate into society in Turkey. New approaches and definitions are needed to touch the actual needs of the refugees to be actively involved into society. Nevertheless, research on the higher education practices of vulnerable groups in general, and of Syrian students in particular, is largely missing.
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Atmatzidou, Soumela K., Chrysanthi N. Βekiari et Stavros N. Demetriadis. « Efficiently Prompting Students When Developing Computational Thinking Skills ». Dans Designing, Constructing, and Programming Robots for Learning, 91–115. IGI Global, 2022. http://dx.doi.org/10.4018/978-1-7998-7443-0.ch005.
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This study investigates the impact of student response modality on the development of computational thinking skills in educational robotics activities. Students of an elementary school were divided into three study groups ('Control', 'Selecting', and 'Writing') that implemented activities based on the same teacher guidance while prompted to provide responses of different modalities. The purpose was to engage students in the development of computational thinking skills, focusing on the basic skills of abstraction, generalization, algorithm, modularity, and debugging. These skills were evaluated at different phases during the activity, using different modality (selection, written, and oral) assessment tools. The results suggest that (1) prompting and eliciting thoughts in the form of written or selected answers proves to be a beneficial strategy, and (2) the two groups, ‘Writing' and ‘Selecting', reach the same level of CT skills, which is significantly higher than the level of the control group.
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McKoy, Megan, S. Spitler, Kelsey Zuchegno, E. Taylor, K. C. Hewitt, John Shallcross, Preston Roman et al. « Theory of Intelligent Collectives ». Dans Advances in Business Information Systems and Analytics, 188–204. IGI Global, 2015. http://dx.doi.org/10.4018/978-1-4666-8368-6.ch012.
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We review our theory of robust intelligence (RI) for groups. We examine the quality of decisions by groups in the laboratory under either majority rule (MR) or consensus rule (CR). Theoretically, engagement in decision-making becomes a factor depending on whether an individual is in a group or in competition between groups. From earlier research, measures of engagement in three-person groups included self-reports, counts of utterances during discussions, and changes in electro-dermal activity (i.e., galvanic skin responses, or GSR). We predicted engagement (number of utterances) would be greater under CR than MR; under MR, we predicted that GSRs would be greater (more attention). Based on partial analyses, participants under CR spoke significantly more often during discussions than MR. As predicted, after de-trending GSR data, we found MR produced higher GSRs and shorter discussions. Our recent work in group size has increased to five participants working on Wason Selection Tasks.
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Sodenkamp, Mariya A., et Leena Suhl. « A Multi-Criteria Vendor Selection and Order Allocation GDSS using a Mixed Alternative and Value Focused Thinking Approach ». Dans Advances in Business Information Systems and Analytics, 108–38. IGI Global, 2014. http://dx.doi.org/10.4018/978-1-4666-5958-2.ch007.
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Vendor selection and order quantity assignment plays a central role in the purchasing activity of manufacturing and trading companies. Evaluation of product and service suppliers for procurement planning requires, on the one hand, accurate identification and exploration of all decision relevant parameters. On the other hand, effective agreements must tackle all parties’ rights, obligations, interests, motives, and values, which are usually conflicting in nature. In this chapter, the authors address the problem of expert group structuring and formalization of participant competences by distinguishing among the a-, ß-, and ?-level experts responsible for the value system establishment, alternatives assessment and auxiliary objects evaluation, respectively. Experts can belong to more than one task community. The triples of a-, ß-, and ?-voting power indices are assigned to the individuals depending on their competence/authority. Moreover, the presented Multi-Criteria Decision Analysis (MCDA)-based framework facilitates selecting appropriate suppliers by the distributed expert groups and improves the quality of order allocation decisions. The usefulness of the proposed approach is demonstrated for the fuel oils and crops purchasing activities in the trading department of Raiffeisen Westfalen Mitte eG in Germany.
Actes de conférences sur le sujet "Group Activity Selection"
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Copeland, Kristen A., Courtney Brown, Zana Percy, Alisa Balestra, Robert Siegel et Christopher Bolling. « Peer-led Group Sessions to Improve Healthful Eating and Physical Activity in a Low-income Primary Care Clinic Population ». Dans Selection of Abstracts From NCE 2016. American Academy of Pediatrics, 2018. http://dx.doi.org/10.1542/peds.141.1_meetingabstract.218.
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Flammini, Michele, et Giovanna Varricchio. « Approximate Strategyproof Mechanisms for the Additively Separable Group Activity Selection Problem ». Dans Thirty-First International Joint Conference on Artificial Intelligence {IJCAI-22}. California : International Joint Conferences on Artificial Intelligence Organization, 2022. http://dx.doi.org/10.24963/ijcai.2022/43.
Texte intégralRésumé :
We investigate strategyproof mechanisms in the Group Activity Selection Problem with the additively separable property. Namely, agents have distinct preferences for each activity and individual weights for the other agents. We evaluate our mechanisms in terms of their approximation ratio with respect to the maximum utilitarian social welfare. We first show that, for arbitrary non-negative preferences, no deterministic mechanism can achieve a bounded approximation ratio. Thus, we provide a randomized k-approximate mechanism, where k is the number of activities, and a corresponding 2-2/(k+1) lower bound. Furthermore, we propose a tight (2 - 1/k)-approximate randomized mechanism when activities are copyable. We then turn our attention to instances where preferences can only be unitary, that is 0 or 1. In this case, we provide a k-approximate deterministic mechanism, which we show to be the best possible one within the class of strategyproof and anonymous mechanisms. We also provide a general lower bound of Ω({\sqrt{k}) when anonymity is no longer a constraint. Finally, we focus on unitary preferences and weights, and prove that, while any mechanism returning the optimum is not strategyproof, there exists a 2-approximate deterministic mechanism.
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Eiben, Eduard, Robert Ganian et Sebastian Ordyniak. « A Structural Approach to Activity Selection ». Dans Twenty-Seventh International Joint Conference on Artificial Intelligence {IJCAI-18}. California : International Joint Conferences on Artificial Intelligence Organization, 2018. http://dx.doi.org/10.24963/ijcai.2018/28.
Texte intégralRésumé :
The general task of finding an assignment of agents to activities under certain stability and rationality constraints has led to the introduction of two prominent problems in the area of computational social choice: Group Activity Selection (GASP) and Stable Invitations (SIP). Here we introduce and study the Comprehensive Activity Selection Problem, which naturally generalizes both of these problems. In particular, we apply the parameterized complexity paradigm, which has already been successfully employed for SIP and GASP. While previous work has focused strongly on parameters such as solution size or number of activities, here we focus on parameters which capture the complexity of agent-to-agent interactions. Our results include a comprehensive complexity map for CAS under various restrictions on the number of activities in combination with restrictions on the complexity of agent interactions.
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Bilò, Vittorio, Angelo Fanelli, Michele Flammini, Gianpiero Monaco et Luca Moscardelli. « Optimality and Nash Stability in Additive Separable Generalized Group Activity Selection Problems ». Dans Twenty-Eighth International Joint Conference on Artificial Intelligence {IJCAI-19}. California : International Joint Conferences on Artificial Intelligence Organization, 2019. http://dx.doi.org/10.24963/ijcai.2019/15.
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The generalized group activity selection problem (GGASP) consists in assigning agents to activities according to their preferences, which depend on both the activity and the set of its participants. We consider additively separable GGASPs, where every agent has a separate valuation for each activity as well as for any other agent, and her overall utility is given by the sum of the valuations she has for the selected activity and its participants. Depending on the nature of the agents' valuations, nine different variants of the problem arise. We completely characterize the complexity of computing a social optimum and provide approximation algorithms for the NP-hard cases. We also focus on Nash stable outcomes, for which we give some complexity results and a full picture of the related performance by providing tights bounds on both the price of anarchy and the price of stability.
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H.S, Rahmat, Hari Wijayanto, Farit Mochamad Afendi, Bagus Sartono, Rahma Anisa et Dewi Anggraini Septianingsih. « Variable-Group Selection on Estimated Metabolites of Curcuma aeruginosa Related to Antioxidant Activity by Using Group Lasso Regression ». Dans Proceedings of the 2nd International Conference on Mathematics and Mathematics Education 2018 (ICM2E 2018). Paris, France : Atlantis Press, 2018. http://dx.doi.org/10.2991/icm2e-18.2018.30.
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Traykova, Tsveta. « STUDY OF THE RELATIONSHIP BETWEEN THE MOTOR ABILITIES OF PRESCHOOL BOYS ». Dans INTERNATIONAL SCIENTIFIC CONGRESS “APPLIED SPORTS SCIENCES”. Scientific Publishing House NSA Press, 2022. http://dx.doi.org/10.37393/icass2022/118.
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ABSTRACT The study of the interrelationship and interdependencies between the children motor abilities is of particular importance for the selection and application of an effective methodology for their development and improvement. The purpose of the study was to establish the dynamics of the degree and character of the relationship between the motor abilities of preschool boys as a result of the application of an experimental physical culture educational program. Methods of study: theoretical analysis, pedagogical experiment, pedagogical testing, statistical methods. A total of 62 boys from the 3rd and 4th age groups participated in the experiment. They were tested twice with 11 motor tests. Results: Most of the recorded correlations between the motor abilities of boys in the 3rd age group were low and statistically insignificant. In the initial study 8 significant moderate correlations were found between them and in the second one only 1, as well as 3 significant correlations. In the 4th age group more statistically reliable relationships between the motor abilities in both studies were registered - 15 moderate and 7 significant correlations at the beginning of the experiment and at the end, respectively, their number was 21 and 7. From the correlation analysis we can make the following conclusion: at the beginning of the experiment in both age groups of boys dominated moderate and statistically reliable correlations between motor abilities, while at the end the number of statistically significant relationships in the 3rd boy group IS decreased (4 in total) while in the group of the bigger boys an increase of the significant correlations was registered (28 in total). So as age increases and a purposeful physical activity program is implemented a positive transfer between the motor abilities of preschool boys is observed.
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Georgiev, Yordan, Nezabravka Gencheva et Todor Marinov. « RESEARCH OF HAMSTRINGS MUSCLES IN CHILDREN SPORTS KARATE ». Dans INTERNATIONAL SCIENTIFIC CONGRESS “APPLIED SPORTS SCIENCES”. Scientific Publishing House NSA Press, 2022. http://dx.doi.org/10.37393/icass2022/162.
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ABSTRACT The functional disorder of the hamstrings muscles is associated with prolonged sitting in a chair, poor posture, lack of motor activity and others. Maintaining elastic muscle tissue is an important factor for children practicing martial arts; karate in particular. This study has the purpose to examine hamstring muscles and their condition in children practicing karate. Methodology During the period between March - May 2022, we worked with 30 children in total, in the age group between 8-10 years old, who were practicing karate or boxing in clubs “Fighters”, located in the city of Varna, and club “Khan Krum”, located in the city of Shumen, respectively. For most accurate results, we formed two separate groups with 15 children each. The participants in our control group were training boxing, whilst the children in our experimental group were practicing karate. All 30 children had been training for a period of 6 months, practicing 2 times per week, one astronomical hour per session. At the beginning of every training session with our experimental group, we treated the hamstring muscles of the participants with post-isometric relaxation. To conclude our findings, we assessed the condition of the hamstring muscles of all 30 children at the beginning and end of the study period, utilizing the method of Laseg and a Seat Test with outstretched legs on the floor with a slope to the toes. Results The results at the end of the study period show that the functional deficit of the hamstring muscles continues to be present in 11 children training boxing. In comparison, only five out of 11 initially diagnosed children with hamstring muscle imbalance from our experimental group showed signs of no improvement. Conclusion The results of this study prove the hypothesis that practicing karate with the inclusion of PIR leads to improved elasticity of the hamstring muscles. The proper selection of physiotherapeutic methods and their regular application could not only heal hamstring muscle stiffness but it could also prevent it, if applied from an early age.
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Avramova, Milena. « RELATIONSHIP BETWEEN ANTHROPOMETRIC INDICATORS AND FITNESS ABILITIES OF ADOLESCENT HANDBALL PLAYERS ». Dans INTERNATIONAL SCIENTIFIC CONGRESS “APPLIED SPORTS SCIENCES”. Scientific Publishing House NSA Press, 2022. http://dx.doi.org/10.37393/icass2022/24.
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ABSTRACT Modern handball is characterized by high motor activity and high intensity of game actions, requiring the player to mobilize his physical, mental, and technical-tactical abilities to the limit. Naturally, this is possible only by maintaining a high level of conditioning abilities, which find external expression in the form of various movements. Objective - The present work is to investigate the relationship between some anthropometric parameters and conditioning abilities of adolescent handball players. The contingent of the study are 11-12-year-old handball players who participated in handball groups at HC “Lokomotiv” Gorna Oryahovitsa. Mathematical and statistical methods - variation and correlation analysis. The analysis of the obtained results for the anthropometric parameters of 11-12-year-old handball players shows that the individual units and segments are relatively uniform. This is due to the selection, as well as the development of the child’s organism. The established level of special motor fitness shows that the studied group is homogeneous in terms of the measured fitness indicators. The presence of certain fluctuations in the handball throw and 800 y ball tests is due to the still un-strengthened musculoskeletal system and the level of technical training.
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Aleksandrova, Velichka. « ADAPTED FOOTBALL PROGRAM TO DEVELOP THE MOTOR SKILLS OF CHILDREN WITH INTELLECTUAL DISABILITIES ». Dans INTERNATIONAL SCIENTIFIC CONGRESS “APPLIED SPORTS SCIENCES”. Scientific Publishing House NSA Press, 2022. http://dx.doi.org/10.37393/icass2022/99.
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ABSTRACT Adapted physical activity and sport is the art and science of development, implementation and control of a specially designed program in a given type of sport for children with various disabilities. The purpose of the present study is to develop and prove the effectiveness of an adapted football program for developing the motor skills of children with intellectual disabilities. The subject of research is the effectiveness of the adapted soccer program, and the subject of the research is the motor qualities of children with intellectual disabilities. Methodology: Participants in the study are a total of 20 children with intellectual disabilities from the SC Adapted Sports. They are divided into two groups: Experimental - includes 10 children participating in a specialized program in adapted football and Control - includes 10 children participating in standard activities in adapted physical activity. Classes were held twice a week according to a previously prepared program that met the specific needs of the children being taught. We used a 20 / 40 m field for mini football with high-quality artificial grass in the „Green Sport“ Sports Complex, Sofia. The experimental program includes a variety of motor actions, with which the goal and tasks of the study were realized. Her duration of application was a total of 9 months. Results: After the applied statistical computer processing, an analysis of the working material of our study was made. To objectify the results of the experiment, the data were systematized and subjected to variation and comparative analysis. Based on the obtained results and their analysis, we found that the experimented program on adapted football for developing the motor qualities of children with intellectual disabilities is effective, observing a tendency to improve the studied indicators of physical ability and functional state. The selection of appropriate tests was fully tailored to the individual characteristics of the children in the target group.
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Prakash, Raghu V., Chandan K. Mukhopadhyay, Prathmesh Pokharkar et Manuel Thomas. « Acoustic Emission Monitoring During Fatigue Crack Growth in Standard C(T) and Miniature Single Edge Notch Tension Specimens ». Dans ASME 2020 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/pvp2020-21416.
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Abstract The fatigue crack growth rate studies in a structural alloy has been carried out using ASTM E-647 standard compact tension (C(T)) specimens and miniature single edge notch tension specimens (SEN(T)) at two different stress ratios of 0.1 and 0.7. Standard C(T) specimen had a dimension of 63.5 × 61 × 8 mm thickness while the miniature SEN(T) specimen had a size of 20 mm effective length × 10 mm wide and 0.7 mm thickness. A starter notch of 0.5 mm was cut using wire EDM process to initiate fatigue crack growth in miniature SEN(T) specimen. A special fixture was designed for testing the miniature SEN(T) specimen. During the fatigue crack growth experiments, Acoustic Emission (AE) activity was monitored on-line using AE sensors from Physical Acoustics, Mistras Group, USA. For the experiments on standard C(T) specimens, a standard probe (R15A) of 15 mm diameter was used, while for small size compact tension specimen, a Nano30 AE probe was used. The crack growth was monitored by visual methods as well as by compliance technique. The cumulative counts and absolute energy information obtained during fatigue crack growth testing was used to correlate the crack growth rate with acoustic emission activity. Empirical fit of data was used to obtain cross-correlation between crack growth rate and AE parameters for both the specimen geometries. The study suggested that suitable selection and placement of sensors is essential to obtain good results using AE sensor technique.
Rapports d'organisations sur le sujet "Group Activity Selection"
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Katzir, Nurit, James Giovannoni, Marla Binzel, Efraim Lewinsohn, Joseph Burger et Arthur Schaffer. Genomic Approach to the Improvement of Fruit Quality in Melon (Cucumis melo) and Related Cucurbit Crops II : Functional Genomics. United States Department of Agriculture, janvier 2010. http://dx.doi.org/10.32747/2010.7592123.bard.
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Background: Genomics tools for enhancement of melon research, with an emphasis on fruit, were developed through a previous BARD project of the PIs (IS -333-02). These included the first public melon EST collection, a database to relay this information to the research community and a publicly available microarray. The current project (IS-3877- 06) aimed to apply these tools for identification of important genes for improvement of melon (Cucumis melo) fruit quality. Specifically, the research plans included expression analysis using the microarray and functional analyses of selected genes. The original project objectives, as they appeared in the approved project, were: Objective 1: Utilization of a public melon microarray developed under the existing project to characterize melon transcriptome activity during the ripening of normal melon fruit (cv. Galia) in order to provide a basis for both a general view of melon transcriptome activity during ripening and for comparison with existing transcriptome data of developing tomato and pepper fruit. Objective 2: Utilization of the same public melon microarray to characterize melon transcriptome activity in lines available in the collection of the Israeli group, focusing on sugar, organic acids and aroma metabolism, so as to identify potentially useful candidates for functional analysis and possible manipulation, through comparison with the general fruit development profile resulting from (1) above. Objective 3: Expansion of our existing melon EST database to include publicly available gene expression data and query tools, as the US group has done with tomato. Objective 4: Selection of 6-8 candidate genes for functional analysis and development of DNA constructs for repression or over-expression. Objective 5: Creation of transgenic melon lines, or transgenic heterologous systems (e.g. E. coli or tomato), to assess putative functions and potential as tools for molecular enhancement of melon fruit quality, using the candidate gene constructs from (4).
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Hansen, Peter J., et Amir Arav. Embryo transfer as a tool for improving fertility of heat-stressed dairy cattle. United States Department of Agriculture, septembre 2007. http://dx.doi.org/10.32747/2007.7587730.bard.
Texte intégralRésumé :
The overall objective of the current proposal is to develop procedures to improve the pregnancy rate achieved following transfer of fresh or cryopreserved embryos produced in the laboratory into heat-stress recipients. The overall hypothesis is that pregnancy rate in heat-stressed lactating cows can be improved by use of embryo transfer and that additional gains in pregnancy rate can be achieved through development of procedures to cryopreserve embryos, select embryos most likely to establish and maintain pregnancy after transfer, and to enhance embryo competence for post-transfer survival through manipulation of culture conditions. The original specific objectives were to 1) optimize procedures for cryopreservation (Israel/US), 2) develop procedures for identifying embryos with the greatest potential for development and survival using the remote monitoring system called EmbryoGuard (Israel), 3) perform field trials to test the efficacy of cryopreservation and the EmbryoGuard selection system for improving pregnancy rates in heat-stressed, lactating cows (US/Israel), 4) test whether selection of fresh or frozen-thawed blastocysts based on measurement of group II caspase activity is an effective means of increasing survival after cryopreservation and post-transfer pregnancy rate (US), and 5) identify genes in blastocysts induced by insulin-like growth factor-1 (IGF-1) (US). In addition to these objectives, additional work was carried out to determine additional cellular determinants of embryonic resistance to heat shock. There were several major achievements. Results of one experiment indicated that survival of embryos to freezing could be improved by treating embryos with cytochalasin B to disrupt the cytoskeleton. An additional improvement in the efficacy of embryo transfer for achieving pregnancy in heat-stressed cows follows from the finding that IGF-1 can improve post-transfer survival of in vitro produced embryos in the summer but not winter. Expression of several genes in the blastocyst was regulated by IGF-1 including IGF binding protein-3, desmocollin II, Na/K ATPase, Bax, heat shock protein 70 and IGF-1 receptor. These genes are likely candidates 1) for developing assays for selection of embryos for transfer and 2) as marker genes for improving culture conditions for embryo production. The fact that IGF-1 improved survival of embryos in heat-stressed recipients only is consistent with the hypothesis that IGF-1 confers cellular thermotolerance to bovine embryos. Other experiments confirmed this action of IGF-1. One action of IGF-1, the ability to block heat-shock induced apoptosis, was shown to be mediated through activation of the phosphatidylinositol 3-kinase pathway. Other cellular determinants of resistance of embryos to elevated temperature were identified including redox status of the embryo and the ceramide signaling pathway. Developmental changes in embryonic apoptosis responses in response to heat shock were described and found to include alterations in the capacity of the embryo to undergo caspase-9 and caspase-3 activation as well as events downstream from caspase-3 activation. With the exception of IGF-1, other possible treatments to improve pregnancy rate to embryo transfer were not effective including selection of embryos for caspase activity, treatment of recipients with GnRH.and bilateral transfer of twin embryos. In conclusion, accomplishments achieved during the grant period have resulted in methods for improving post-transfer survival of in vitro produced embryos transferred into heat-stressed cows and have lead to additional avenues for research to increase embryo resistance to elevated temperature and improve survival to cryopreservation. In addition, embryo transfer of vitrified IVF embryos increased significantly the pregnancy rate in repeated breeder cows.
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Altstein, Miriam, et Ronald Nachman. Rationally designed insect neuropeptide agonists and antagonists : application for the characterization of the pyrokinin/Pban mechanisms of action in insects. United States Department of Agriculture, octobre 2006. http://dx.doi.org/10.32747/2006.7587235.bard.
Texte intégralRésumé :
The general objective of this BARD project focused on rationally designed insect neuropeptide (NP) agonists and antagonists, their application for the characterization of the mechanisms of action of the pyrokinin/PBAN (PK-PBAN) family and the development of biostable, bioavailable versions that can provide the basis for development of novel, environmentally-friendly pest insect control agents. The specific objectives of the study, as originally proposed, were to: (i) Test stimulatory potencies of rationally designed backbone cyclic (BBC) peptides on pheromonotropic, melanotropic, myotropic and pupariation activities; (ii) Test the inhibitory potencies of the BBC compounds on the above activities evoked either by synthetic peptides (PBAN, LPK, myotropin and pheromonotropin) or by the natural endogenous mechanism; (iii) Determine the bioavailability of the most potent BBC compounds that will be found in (ii); (iv) Design, synthesize and examine novel PK/PBAN analogs with enhanced bioavailability and receptor binding; (v) Design and synthesize ‘magic bullet’ analogs and examine their ability to selectively kill cells expressing the PK/PBAN receptor. To achieve these goals the agonistic and antagonistic activities/properties of rationally designed linear and BBC neuropeptide (NP) were thoroughly studied and the information obtained was further used for the design and synthesis of improved compounds toward the design of an insecticide prototype. The study revealed important information on the structure activity relationship (SAR) of agonistic/antagonistic peptides, including definitive identification of the orientation of the Pro residue as trans for agonist activity in 4 PK/PBANbioassays (pheromonotropic, pupariation, melanotropic, & hindgut contractile) and a PK-related CAP₂b bioassay (diuretic); indications that led to the identification of a novel scaffold to develop biostbiostable, bioavailable peptidomimetic PK/PBANagonists/antagonists. The work led to the development of an arsenal of PK/PBAN antagonists with a variety of selectivity profiles; whether between different PKbioassays, or within the same bioassay between different natural elicitors. Examples include selective and non-selective BBC and novel amphiphilic PK pheromonotropic and melanotropic antagonists some of which are capable of penetrating the moth cuticle in efficacious quantities. One of the latter analog group demonstrated unprecedented versatility in its ability to antagonize a broad spectrum of pheromonotropic elicitors. A novel, transPro mimetic motif was proposed & used to develop a strong, selective PK agonist of the melanotropic bioassay in moths. The first antagonist (pure) of PK-related CAP₂b diuresis in flies was developed using a cisPro mimetic motif; an indication that while a transPro orientation is associated with receptor agonism, a cisPro orientation is linked with an antagonist interaction. A novel, biostablePK analog, incorporating β-amino acids at key peptidase-susceptible sites, exhibited in vivo pheromonotropic activity that by far exceeded that of PBAN when applied topically. Direct analysis of neural tissue by state-of-the-art MALDI-TOF/TOF mass spectrometry was used to identify specific PK/PK-related peptides native to eight arthropod pest species [house (M. domestica), stable (S. calcitrans), horn (H. irritans) & flesh (N. bullata) flies; Southern cattle fever tick (B. microplus), European tick (I. ricinus), yellow fever mosquito (A. aegypti), & Southern Green Stink Bug (N. viridula)]; including the unprecedented identification of mass-identical Leu/Ile residues and the first identification of NPs from a tick or the CNS of Hemiptera. Evidence was obtained for the selection of Neb-PK-2 as the primary pupariation factor of the flesh fly (N. bullata) among native PK/PK-related candidates. The peptidomic techniques were also used to map the location of PK/PK-related NP in the nervous system of the model fly D. melanogaster. Knowledge of specific PK sequences can aid in the future design of species specific (or non-specific) NP agonists/antagonists. In addition, the study led to the first cloning of a PK/PBAN receptor from insect larvae (S. littoralis), providing the basis for SAR analysis for the future design of 2ⁿᵈgeneration selective and/or nonselective agonists/antagonists. Development of a microplate ligand binding assay using the PK/PBAN pheromone gland receptor was also carried out. The assay will enable screening, including high throughput, of various libraries (chemical, molecular & natural product) for the discovery of receptor specific agonists/antagonists. In summary, the body of work achieves several key milestones and brings us significantly closer to the development of novel, environmentally friendly pest insect management agents based on insect PK/PBANNPs capable of disrupting critical NP-regulated functions.
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Fluhr, Robert, et Maor Bar-Peled. Novel Lectin Controls Wound-responses in Arabidopsis. United States Department of Agriculture, janvier 2012. http://dx.doi.org/10.32747/2012.7697123.bard.
Texte intégralRésumé :
Innate immune responses in animals and plants involve receptors that recognize microbe-associated molecules. In plants, one set of this defense system is characterized by large families of TIR–nucleotide binding site–leucine-rich repeat (TIR-NBS-LRR) resistance genes. The direct interaction between plant proteins harboring the TIR domain with proteins that transmit and facilitate a signaling pathway has yet to be shown. The Arabidopsis genome encodes TIR-domain containing genes that lack NBS and LRR whose functions are unknown. Here we investigated the functional role of such protein, TLW1 (TIR LECTIN WOUNDRESPONSIVE1). The TLW1 gene encodes a protein with two domains: a TIR domain linked to a lectin-containing domain. Our specific aim in this proposal was to examine the ramifications of the TL1-glycan interaction by; A) The functional characterization of TL1 activity in the context of plant wound response and B) Examine the hypothesis that wounding induced specific polysaccharides and examine them as candidates for TL-1 interactive glycan compounds. The Weizmann group showed TLW1 transcripts are rapidly induced by wounding in a JA-independent pathway and T-DNA-tagged tlw1 mutants that lack TLW1 transcripts, fail to initiate the full systemic wound response. Transcriptome methodology analysis was set up and transcriptome analyses indicates a two-fold reduced level of JA-responsive but not JA-independent transcripts. The TIR domain of TLW1 was found to interact directly with the KAT2/PED1 gene product responsible for the final b-oxidation steps in peroxisomal-basedJA biosynthesis. To identify potential binding target(s) of TL1 in plant wound response, the CCRC group first expressed recombinant TL1 in bacterial cells and optimized conditions for the protein expression. TL1 was most highly expressed in ArcticExpress cell line. Different types of extraction buffers and extraction methods were used to prepare plant extracts for TL1 binding assay. Optimized condition for glycan labeling was determined, and 2-aminobenzamide was used to label plant extracts. Sensitivity of MALDI and LC-MS using standard glycans. THAP (2,4,6- Trihydroxyacetophenone) showed minimal background peaks at positive mode of MALDI, however, it was insensitive with a minimum detection level of 100 ng. Using LC-MS, sensitivity was highly increased enough to detect 30 pmol concentration. However, patterns of total glycans displayed no significant difference between different extraction conditions when samples were separated with Dionex ICS-2000 ion chromatography system. Transgenic plants over-expressing lectin domains were generated to obtain active lectin domain in plant cells. Insertion of the overexpression construct into the plant genome was confirmed by antibiotic selection and genomic DNA PCR. However, RT-PCR analysis was not able to detect increased level of the transcripts. Binding ability of azelaic acid to recombinant TL1. Azelaic acid was detected in GST-TL1 elution fraction, however, DHB matrix has the same mass in background signals, which needs to be further tested on other matrices. The major findings showed the importance of TLW1 in regulating wound response. The findings demonstrate completely novel and unexpected TIR domain interactions and reveal a control nexus and mechanism that contributes to the propagation of wound responses in Arabidopsis. The implications are to our understanding of the function of TIR domains and to the notion that early molecular events occur systemically within minutes of a plant sustaining a wound. A WEB site (http://genome.weizmann.ac.il/hormonometer/) was set up that enables scientists to interact with a collated plant hormone database.
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Ficht, Thomas, Gary Splitter, Menachem Banai et Menachem Davidson. Characterization of B. Melinensis REV 1 Attenuated Mutants. United States Department of Agriculture, décembre 2000. http://dx.doi.org/10.32747/2000.7580667.bard.
Texte intégralRésumé :
Brucella Mutagenesis (TAMU) The working hypothesis for this study was that survival of Brucella vaccines was directly related to their persistence in the host. This premise is based on previously published work detailing the survival of the currently employed vaccine strains S19 and Rev 1. The approach employed signature-tagged mutagenesis to construct mutants interrupted in individual genes, and the mouse model to identify mutants with attenuated virulence/survival. Intracellular survival in macrophages is the key to both reproductive disease in ruminants and reticuloendothelial disease observed in most other species. Therefore, the mouse model permitted selection of mutants of reduced intracellular survival that would limit their ability to cause reproductive disease in ruminants. Several classes of mutants were expected. Colonization/invasion requires gene products that enhance host-agent interaction or increase resistance to antibacterial activity in macrophages. The establishment of chronic infection requires gene products necessary for intracellular bacterial growth. Maintenance of chronic infection requires gene products that sustain a low-level metabolism during periods characterized little or no growth (1, 2). Of these mutants, the latter group was of greatest interest with regard to our originally stated premise. However, the results obtained do not necessarily support a simplistic model of vaccine efficacy, i.e., long-survival of vaccine strains provides better immunity. Our conclusion can only be that optimal vaccines will only be developed with a thorough understanding of host agent interaction, and will be preferable to the use of fortuitous isolates of unknown genetic background. Each mutant could be distinguished from among a group of mutants by PCR amplification of the signature tag (5). This approach permitted infection of mice with pools of different mutants (including the parental wild-type as a control) and identified 40 mutants with apparently defective survival characteristics that were tentatively assigned to three distinct classes or groups. Group I (n=13) contained organisms that exhibited reduced survival at two weeks post-infection. Organisms in this group were recovered at normal levels by eight weeks and were not studied further, since they may persist in the host. Group II (n=11) contained organisms that were reduced by 2 weeks post infection and remained at reduced levels at eight weeks post-infection. Group III (n=16) contained mutants that were normal at two weeks, but recovered at reduced levels at eight weeks. A subset of these mutants (n= 15) was confirmed to be attenuated in mixed infections (1:1) with the parental wild-type. One of these mutants was eliminated from consideration due to a reduced growth rate in vitro that may account for its apparent growth defect in the mouse model. Although the original plan involved construction of the mutant bank in B. melitensis Rev 1 the low transformability of this strain, prevented accumulation of the necessary number of mutants. In addition, the probability that Rev 1 already carries one genetic defect increases the likelihood that a second defect will severely compromise the survival of this organism. Once key genes have been identified, it is relatively easy to prepare the appropriate genetic constructs (knockouts) lacking these genes in B. melitensis Rev 1 or any other genetic background. The construction of "designer" vaccines is expected to improve immune protection resulting from minor sequence variation corresponding to geographically distinct isolates or to design vaccines for use in specific hosts. A.2 Mouse Model of Brucella Infection (UWISC) Interferon regulatory factor-1-deficient (IRF-1-/- mice have diverse immunodeficient phenotypes that are necessary for conferring proper immune protection to intracellular bacterial infection, such as a 90% reduction of CD8+ T cells, functionally impaired NK cells, as well as a deficiency in iNOS and IL-12p40 induction. Interestingly, IRF-1-/- mice infected with diverse Brucella abortus strains reacted differently in a death and survival manner depending on the dose of injection and the level of virulence. Notably, 50% of IRF-1-/- mice intraperitoneally infected with a sublethal dose in C57BL/6 mice, i.e., 5 x 105 CFU of virulent S2308 or the attenuated vaccine S19, died at 10 and 20 days post-infection, respectively. Interestingly, the same dose of RB51, an attenuated new vaccine strain, did not induce the death of IRF-1-/- mice for the 4 weeks of infection. IRF-1-/- mice infected with four more other genetically manipulated S2308 mutants at 5 x 105 CFU also reacted in a death or survival manner depending on the level of virulence. Splenic CFU from C57BL/6 mice infected with 5 x 105 CFU of S2308, S19, or RB51, as well as four different S2308 mutants supports the finding that reduced virulence correlates with survival Of IRF-1-/- mice. Therefore, these results suggest that IRF-1 regulation of multi-gene transcription plays a crucial role in controlling B. abortus infection, and IRF-1 mice could be used as an animal model to determine the degree of B. abortus virulence by examining death or survival. A3 Diagnostic Tests for Detection of B. melitensis Rev 1 (Kimron) In this project we developed an effective PCR tool that can distinguish between Rev1 field isolates and B. melitensis virulent field strains. This has allowed, for the first time, to monitor epidemiological outbreaks of Rev1 infection in vaccinated flocks and to clearly demonstrate horizontal transfer of the strain from vaccinated ewes to unvaccinated ones. Moreover, two human isolates were characterized as Rev1 isolates implying the risk of use of improperly controlled lots of the vaccine in the national campaign. Since atypical B. melitensis biotype 1 strains have been characterized in Israel, the PCR technique has unequivocally demonstrated that strain Rev1 has not diverted into a virulent mutant. In addition, we could demonstrate that very likely a new prototype biotype 1 strain has evolved in the Middle East compared to the classical strain 16M. All the Israeli field strains have been shown to differ from strain 16M in the PstI digestion profile of the omp2a gene sequence suggesting that the local strains were possibly developed as a separate branch of B. melitensis. Should this be confirmed these data suggest that the Rev1 vaccine may not be an optimal vaccine strain for the Israeli flocks as it shares the same omp2 PstI digestion profile as strain 16M.
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Altstein, Miriam, et Ronald J. Nachman. Rational Design of Insect Control Agent Prototypes Based on Pyrokinin/PBAN Neuropeptide Antagonists. United States Department of Agriculture, août 2013. http://dx.doi.org/10.32747/2013.7593398.bard.
Texte intégralRésumé :
The general objective of this study was to develop rationally designed mimetic antagonists (and agonists) of the PK/PBAN Np class with enhanced bio-stability and bioavailability as prototypes for effective and environmentally friendly pest insect management agents. The PK/PBAN family is a multifunctional group of Nps that mediates key functions in insects (sex pheromone biosynthesis, cuticular melanization, myotropic activity, diapause and pupal development) and is, therefore, of high scientific and applied interest. The objectives of the current study were: (i) to identify an antagonist biophores (ii) to develop an arsenal of amphiphilic topically active PK/PBAN antagonists with an array of different time-release profiles based on the previously developed prototype analog; (iii) to develop rationally designed non-peptide SMLs based on the antagonist biophore determined in (i) and evaluate them in cloned receptor microplate binding assays and by pheromonotropic, melanotropic and pupariation in vivo assays. (iv) to clone PK/PBAN receptors (PK/PBAN-Rs) for further understanding of receptor-ligand interactions; (v) to develop microplate binding assays for screening the above SMLs. In the course of the granting period A series of amphiphilic PK/PBAN analogs based on a linear lead antagonist from the previous BARD grant was synthesized that incorporated a diverse array of hydrophobic groups (HR-Suc-A[dF]PRLa). Others were synthesized via the attachment of polyethylene glycol (PEG) polymers. A hydrophobic, biostablePK/PBAN/DH analog DH-2Abf-K prevented the onset of the protective state of diapause in H. zea pupae [EC50=7 pmol/larva] following injection into the preceding larval stage. It effectively induces the crop pest to commit a form of ‘ecological suicide’. Evaluation of a set of amphiphilic PK analogs with a diverse array of hydrophobic groups of the formula HR-Suc-FTPRLa led to the identification of analog T-63 (HR=Decyl) that increased the extent of diapause termination by a factor of 70% when applied topically to newly emerged pupae. Another biostablePK analog PK-Oic-1 featured anti-feedant and aphicidal properties that matched the potency of some commercial aphicides. Native PK showed no significant activity. The aphicidal effects were blocked by a new PEGylated PK antagonist analog PK-dF-PEG4, suggesting that the activity is mediated by a PK/PBAN receptor and therefore indicative of a novel and selective mode-of-action. Using a novel transPro mimetic motif (dihydroimidazole; ‘Jones’) developed in previous BARD-sponsored work, the first antagonist for the diapause hormone (DH), DH-Jo, was developed and shown to block over 50% of H. zea pupal diapause termination activity of native DH. This novel antagonist development strategy may be applicable to other invertebrate and vertebrate hormones that feature a transPro in the active core. The research identifies a critical component of the antagonist biophore for this PK/PBAN receptor subtype, i.e. a trans-oriented Pro. Additional work led to the molecular cloning and functional characterization of the DH receptor from H. zea, allowing for the discovery of three other DH antagonist analogs: Drosophila ETH, a β-AA analog, and a dF analog. The receptor experiments identified an agonist (DH-2Abf-dA) with a maximal response greater than native DH. ‘Deconvolution’ of a rationally-designed nonpeptide heterocyclic combinatorial library with a cyclic bis-guanidino (BG) scaffold led to discovery of several members that elicited activity in a pupariation acceleration assay, and one that also showed activity in an H. zea diapause termination assay, eliciting a maximal response of 90%. Molecular cloning and functional characterization of a CAP2b antidiuretic receptor from the kissing bug (R. prolixus) as well as the first CAP2b and PK receptors from a tick was also achieved. Notably, the PK/PBAN-like receptor from the cattle fever tick is unique among known PK/PBAN and CAP2b receptors in that it can interact with both ligand types, providing further evidence for an evolutionary relationship between these two NP families. In the course of the granting period we also managed to clone the PK/PBAN-R of H. peltigera, to express it and the S. littoralis-R Sf-9 cells and to evaluate their interaction with a variety of PK/PBAN ligands. In addition, three functional microplate assays in a HTS format have been developed: a cell-membrane competitive ligand binding assay; a Ca flux assay and a whole cell cAMP ELISA. The Ca flux assay has been used for receptor characterization due to its extremely high sensitivity. Computer homology studies were carried out to predict both receptor’s SAR and based on this analysis 8 mutants have been generated. The bioavailability of small linear antagonistic peptides has been evaluated and was found to be highly effective as sex pheromone biosynthesis inhibitors. The activity of 11 new amphiphilic analogs has also been evaluated. Unfortunately, due to a problem with the Heliothis moth colony we were unable to select those with pheromonotropic antagonistic activity and further check their bioavailability. Six peptides exhibited some melanotropic antagonistic activity but due to the low inhibitory effect the peptides were not further tested for bioavailability in S. littoralis larvae. Despite the fact that no new antagonistic peptides were discovered in the course of this granting period the results contribute to a better understanding of the interaction of the PK/PBAN family of Nps with their receptors, provided several HT assays for screening of libraries of various origin for presence of PK/PBAN-Ragonists and antagonists and provided important practical information for the further design of new, peptide-based insecticide prototypes aimed at the disruption of key neuroendocrine physiological functions in pest insects.
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Sadka, Avi, Mikeal L. Roose et Yair Erner. Molecular Genetic Analysis of Citric Acid Accumulation in Citrus Fruit. United States Department of Agriculture, mars 2001. http://dx.doi.org/10.32747/2001.7573071.bard.
Texte intégralRésumé :
The acid content of the juice sac cells is a major determinant of maturity and fruit quality in citrus. Many citrus varieties accumulate acid in concentrations that exceed market desires, reducing grower income and consumer satisfaction. Pulp acidity is thought to be dependent on two mechanisms: the accumulation of citric acid in the vacuoles of the juice sac cells, and acidification of the vacuole. The major aim of the project was to direct effort toward understanding the mechanism of citric acid accumulation in the fruit. The following objectives were suggested: Measure the activity of enzymes likely to be involved in acid accumulation and follow their pattern of expression in developing fruit (Sadka, Erner). Identify and clone genes which are associated with high and low acid phenotypes and with elevated acid level (Roose, Sadka, Erner). Convert RAPD markers that map near a gene that causes low acid phenotype to specific co dominant markers (Roose). Use genetic co segregation to test whether specific gene products are responsible for low acid phenotype (Roose and Sadka). Objective 1 was fully achieved. Most of the enzymes of organic acid metabolism were cloned from lemon pulp. Their expression was studied during fruit development in low and high acid varieties. The activity and expression of citrate synthase, aconitase and NADP-isocitrate dehydrogenase (IDH) were studied in detail. The role that each enzyme plays in acid accumulation and decline was evaluated. As a result, a better understanding of the metabolic changes that contribute to acid accumulation was achieved. It was found that the activity of the mitochondrial aconitase is greatly reduced early in high-acid fruits, but not in acidless ones, suggesting that this enzyme plays an important role in acid accumulation. In addition, it was demonstrated that increases in the cytosolic forms of aconitase and NADP-IDH towards fruit maturation play probably a major role in acid decline. Our studies also demonstrated that the two mechanisms that contribute to fruit acidity, vacuolar acidification and citric acid accumulation, are independent, although they are tightly co-regulated. Additional, we demonstrated that sodium arsenite, which reduce fruit acidity, causes a transient inhibition in the activity of citrate synthase, but an induction in the gene expression. This part of the work has resulted in 4 papers. Objective 3 was also fully achieved. Using bulked segregant analysis, three random amplified polymorphic DNA (RAPD) markers were identified as linked to acitric, a gene controlling the acidless phenotype of pummelo 2240. One of them, which mapped 1.2 cM from acitric was converted into sequence characterized amplified region (SCAR marker, and into co dominant restriction length polymorphism (RFLP) marker. These markers were highly polymorphic among 59 citrus accessions, and therefore, they should be useful for selecting seedling progeny heterozygous for acitric in nearly all crosses between pummelo 2240 and other citrus genotypes. This part of the project resulted in one paper. Objective 4 was also fully achieved. Clones isolated by the Israeli group were sent to the American laboratory for co segregation analysis. However, none of them seemed to co segregate with the low acid phenotype. Both laboratories invested much effort in achieving the goals of Objective 2, namely the isolation of genes that are elevated in expression in low and high acid phenotypes, and in tissue cultures treated with arsenite (a treatment which reduces fruit acidity). However, conventional differential display and restriction fragment differential display analyses could not identify any differentially expressed genes. The isolation of such genes was the major aim of a continuation project, which was recently submitted.
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Ohad, Itzhak, et Himadri Pakrasi. Role of Cytochrome B559 in Photoinhibition. United States Department of Agriculture, décembre 1995. http://dx.doi.org/10.32747/1995.7613031.bard.
Texte intégralRésumé :
The aim of this research project was to obtain information on the role of the cytochrome b559 in the function of Photosystem-II (PSII) with special emphasis on the light induced photo inactivation of PSII and turnover of the photochemical reaction center II protein subunit RCII-D1. The major goals of this project were: 1) Isolation and sequencing of the Chlamydomonas chloroplast psbE and psbF genes encoding the cytochrome b559 a and b subunits respectively; 2) Generation of site directed mutants and testing the effect of such mutation on the function of PSII under various light conditions; 3) To obtain further information on the mechanism of the light induced degradation and replacement of the PSII core proteins. This information shall serve as a basis for the understanding of the role of the cytochrome b559 in the process of photoinhibition and recovery of photosynthetic activity as well as during low light induced turnover of the D1 protein. Unlike in other organisms in which the psbE and psbF genes encoding the a and b subunits of cytochrome b559, are part of an operon which also includes the psbL and psbJ genes, in Chlamydomonas these genes are transcribed from different regions of the chloroplast chromosome. The charge distribution of the derived amino-acid sequences of psbE and psbF gene products differs from that of the corresponding genes in other organisms as far as the rule of "positive charge in" is concerned relative to the process of the polypeptide insertion in the thylakoid membrane. However, the sum of the charges of both subunits corresponds to the above rule possibly indicating co-insertion of both subunits in the process of cytochrome b559 assembly. A plasmid designed for the introduction of site-specific mutations into the psbF gene of C. reinhardtii. was constructed. The vector consists of a DNA fragment from the chromosome of C. reinhardtii which spans the region of the psbF gene, upstream of which the spectinomycin-resistance-conferring aadA cassette was inserted. This vector was successfully used to transform wild type C. reinhardtii cells. The spectinomycin resistant strain thus obtained can grow autotrophically and does not show significant changes as compared to the wild-type strain in PSII activity. The following mutations have been introduced in the psbF gene: H23M; H23Y; W19L and W19. The replacement of H23 involved in the heme binding to M and Y was meant to permit heme binding but eventually alter some or all of the electron transport properties of the mutated cytochrome. Tryptophane W19, a strictly conserved residue, is proximal to the heme and may interact with the tetrapyrole ring. Therefore its replacement may effect the heme properties. A change to tyrosine may have a lesser affect on the potential or electron transfer rate while a replacement of W19 by leucine is meant to introduce a more prominent disturbance in these parameters. Two of the mutants, FW19L and FH23M have segregated already and are homoplasmic. The rest are still grown under selection conditions until complete segregation will be obtained. All mutants contain assembled and functional PSII exhibiting an increased sensitivity of PSII to the light. Work is still in progress for the detailed characterization of the mutants PSII properties. A tobacco mutant, S6, obtained by Maliga and coworkers harboring the F26S mutation in the b subunit was made available to us and was characterized. Measurements of PSII charge separation and recombination, polypeptide content and electron flow indicates that this mutation indeed results in light sensitivity. Presently further work is in progress in the detailed characterization of the properties of all the above mutants. Information was obtained demonstrating that photoinactivation of PSII in vivo initiates a series of progressive changes in the properties of RCII which result in an irreversible modification of the RCII-D1 protein leading to its degradation and replacement. The cleavage process of the modified RCII-D1 protein is regulated by the occupancy of the QB site of RCII by plastoquinone. Newly synthesized D1 protein is not accumulated in a stable form unless integrated in reassembled RCII. Thus the degradation of the irreversibly modified RCII-D1 protein is essential for the recovery process. The light induced degradation of the RCII-D1 protein is rapid in mutants lacking the pD1 processing protease such as in the LF-1 mutant of the unicellular alga Scenedesmus obliquus. In this case the Mn binding site of PSII is abolished, the water oxidation process is inhibited and harmful cation radicals are formed following light induced electron flow in PSII. In such mutants photo-inactivation of PSII is rapid, it is not protected by ligands binding at the QB site and the degradation of the inactivated RCII-D1 occurs rapidly also in the dark. Furthermore the degraded D1 protein can be replaced in the dark in absence of light driven redox controlled reactions. The replacement of the RCII-D1 protein involves the de novo synthesis of the precursor protein, pD1, and its processing at the C-terminus end by an unknown processing protease. In the frame of this work, a gene previously isolated and sequenced by Dr. Pakrasi's group has been identified as encoding the RCII-pD1 C-terminus processing protease in the cyanobacterium Synechocystis sp. PCC 6803. The deduced sequence of the ctpA protein shows significant similarity to the bovine, human and insect interphotoreceptor retinoid-binding proteins. Results obtained using C. reinhardtii cells exposes to low light or series of single turnover light flashes have been also obtained indicating that the process of RCII-D1 protein turnover under non-photoinactivating conditions (low light) may be related to charge recombination in RCII due to back electron flow from the semiquinone QB- to the oxidised S2,3 states of the Mn cluster involved in the water oxidation process.
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Lers, Amnon, Majid R. Foolad et Haya Friedman. genetic basis for postharvest chilling tolerance in tomato fruit. United States Department of Agriculture, janvier 2014. http://dx.doi.org/10.32747/2014.7600014.bard.
Texte intégralRésumé :
ABSTRACT Postharvest losses of fresh produce are estimated globally to be around 30%. Reducing these losses is considered a major solution to ensure global food security. Storage at low temperatures is an efficient practice to prolong postharvest performance of crops with minimal negative impact on produce quality or human health and the environment. However, many fresh produce commodities are susceptible to chilling temperatures, and the application of cold storage is limited as it would cause physiological chilling injury (CI) leading to reduced produce quality. Further, the primary CI becomes a preferred site for pathogens leading to decay and massive produce losses. Thus, chilling sensitive crops should be stored at higher minimal temperatures, which curtails their marketing life and in some cases necessitates the use of other storage strategies. Development of new knowledge about the biological basis for chilling tolerance in fruits and vegetables should allow development of both new varieties more tolerant to cold, and more efficient postharvest storage treatments and storage conditions. In order to improve the agricultural performance of modern crop varieties, including tomato, there is great potential in introgression of marker-defined genomic regions from wild species onto the background of elite breeding lines. To exploit this potential for improving tomato fruit chilling tolerance during postharvest storage, we have used in this research a recombinant inbred line (RIL) population derived from a cross between the red-fruited tomato wild species SolanumpimpinellifoliumL. accession LA2093 and an advanced Solanum lycopersicumL. tomato breeding line NCEBR-1, developed in the laboratory of the US co-PI. The original specific objectives were: 1) Screening of RIL population resulting from the cross NCEBR1 X LA2093 for fruit chilling response during postharvest storage and estimation of its heritability; 2) Perform a transcriptopmic and bioinformatics analysis for the two parental lines following exposure to chilling storage. During the course of the project, we learned that we could measure greater differences in chilling responses among specific RILs compared to that observed between the two parental lines, and thus we decided not to perform transcriptomic analysis and instead invest our efforts more on characterization of the RILs. Performing the transcriptomic analysis for several RILs, which significantly differ in their chilling tolerance/sensitivity, at a later stage could result with more significant insights. The RIL population, (172 lines), was used in field experiment in which fruits were examined for chilling sensitivity by determining CI severity. Following the field experiments, including 4 harvest days and CI measurements, two extreme tails of the response distribution, each consisting of 11 RILs exhibiting either high sensitivity or tolerance to chilling stress, were identified and were further examined for chilling response in greenhouse experiments. Across the RILs, we found significant (P < 0.01) correlation between field and greenhouse grown plants in fruit CI. Two groups of 5 RILs, whose fruits exhibited reproducible chilling tolerant/sensitive phenotypes in both field and greenhouse experiments, were selected for further analyses. Numerous genetic, physiological, biochemical and molecular variations were investigated in response to postharvest chilling stress in the selected RILs. We confirmed the differential response of the parental lines of the RIL population to chilling stress, and examined the extent of variation in the RIL population in response to chilling treatment. We determined parameters which would be useful for further characterization of chilling response in the RIL population. These included chlorophyll fluorescence Fv/Fm, water loss, total non-enzymatic potential of antioxidant activity, ascorbate and proline content, and expression of LeCBF1 gene, known to be associated with cold acclimation. These parameters could be used in continuation studies for the identification and genetic mapping of loci contributing to chilling tolerance in this population, and identifying genetic markers associated with chilling tolerance in tomato. Once genetic markers associated with chilling tolerance are identified, the trait could be transferred to different genetic background via marker-assisted selection (MAS) and breeding. The collaborative research established in this program has resulted in new information and insights in this area of research and the collaboration will be continued to obtain further insights into the genetic, molecular biology and physiology of postharvest chilling tolerance in tomato fruit. The US Co-PI, developed the RIL population that was used for screening and measurement of the relevant chilling stress responses and conducted statistical analyses of the data. Because we were not able to grow the RIL population under field conditions in two successive generations, we could not estimate heritability of response to chilling temperatures. However, we plan to continue the research, grow the RIL progeny in the field again, and determine heritability of chilling tolerance in a near future. The IS and US investigators interacted regularly and plan to continue and expand on this study, since combing the expertise of the Co-PI in genetics and breeding with that of the PI in postharvest physiology and molecular biology will have great impact on this line of research, given the significant findings of this one-year feasibility project.
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Smit, Amelia, Kate Dunlop, Nehal Singh, Diona Damian, Kylie Vuong et Anne Cust. Primary prevention of skin cancer in primary care settings. The Sax Institute, août 2022. http://dx.doi.org/10.57022/qpsm1481.
Texte intégralRésumé :
Overview Skin cancer prevention is a component of the new Cancer Plan 2022–27, which guides the work of the Cancer Institute NSW. To lessen the impact of skin cancer on the community, the Cancer Institute NSW works closely with the NSW Skin Cancer Prevention Advisory Committee, comprising governmental and non-governmental organisation representatives, to develop and implement the NSW Skin Cancer Prevention Strategy. Primary Health Networks and primary care providers are seen as important stakeholders in this work. To guide improvements in skin cancer prevention and inform the development of the next NSW Skin Cancer Prevention Strategy, an up-to-date review of the evidence on the effectiveness and feasibility of skin cancer prevention activities in primary care is required. A research team led by the Daffodil Centre, a joint venture between the University of Sydney and Cancer Council NSW, was contracted to undertake an Evidence Check review to address the questions below. Evidence Check questions This Evidence Check aimed to address the following questions: Question 1: What skin cancer primary prevention activities can be effectively administered in primary care settings? As part of this, identify the key components of such messages, strategies, programs or initiatives that have been effectively implemented and their feasibility in the NSW/Australian context. Question 2: What are the main barriers and enablers for primary care providers in delivering skin cancer primary prevention activities within their setting? Summary of methods The research team conducted a detailed analysis of the published and grey literature, based on a comprehensive search. We developed the search strategy in consultation with a medical librarian at the University of Sydney and the Cancer Institute NSW team, and implemented it across the databases Embase, MEDLINE, PsycInfo, Scopus, Cochrane Central and CINAHL. Results were exported and uploaded to Covidence for screening and further selection. The search strategy was designed according to the SPIDER tool for Qualitative and Mixed-Methods Evidence Synthesis, which is a systematic strategy for searching qualitative and mixed-methods research studies. The SPIDER tool facilitates rigour in research by defining key elements of non-quantitative research questions. We included peer-reviewed and grey literature that included skin cancer primary prevention strategies/ interventions/ techniques/ programs within primary care settings, e.g. involving general practitioners and primary care nurses. The literature was limited to publications since 2014, and for studies or programs conducted in Australia, the UK, New Zealand, Canada, Ireland, Western Europe and Scandinavia. We also included relevant systematic reviews and evidence syntheses based on a range of international evidence where also relevant to the Australian context. To address Question 1, about the effectiveness of skin cancer prevention activities in primary care settings, we summarised findings from the Evidence Check according to different skin cancer prevention activities. To address Question 2, about the barriers and enablers of skin cancer prevention activities in primary care settings, we summarised findings according to the Consolidated Framework for Implementation Research (CFIR). The CFIR is a framework for identifying important implementation considerations for novel interventions in healthcare settings and provides a practical guide for systematically assessing potential barriers and facilitators in preparation for implementing a new activity or program. We assessed study quality using the National Health and Medical Research Council (NHMRC) levels of evidence. Key findings We identified 25 peer-reviewed journal articles that met the eligibility criteria and we included these in the Evidence Check. Eight of the studies were conducted in Australia, six in the UK, and the others elsewhere (mainly other European countries). In addition, the grey literature search identified four relevant guidelines, 12 education/training resources, two Cancer Care pathways, two position statements, three reports and five other resources that we included in the Evidence Check. Question 1 (related to effectiveness) We categorised the studies into different types of skin cancer prevention activities: behavioural counselling (n=3); risk assessment and delivering risk-tailored information (n=10); new technologies for early detection and accompanying prevention advice (n=4); and education and training programs for general practitioners (GPs) and primary care nurses regarding skin cancer prevention (n=3). There was good evidence that behavioural counselling interventions can result in a small improvement in sun protection behaviours among adults with fair skin types (defined as ivory or pale skin, light hair and eye colour, freckles, or those who sunburn easily), which would include the majority of Australians. It was found that clinicians play an important role in counselling patients about sun-protective behaviours, and recommended tailoring messages to the age and demographics of target groups (e.g. high-risk groups) to have maximal influence on behaviours. Several web-based melanoma risk prediction tools are now available in Australia, mainly designed for health professionals to identify patients’ risk of a new or subsequent primary melanoma and guide discussions with patients about primary prevention and early detection. Intervention studies have demonstrated that use of these melanoma risk prediction tools is feasible and acceptable to participants in primary care settings, and there is some evidence, including from Australian studies, that using these risk prediction tools to tailor primary prevention and early detection messages can improve sun-related behaviours. Some studies examined novel technologies, such as apps, to support early detection through skin examinations, including a very limited focus on the provision of preventive advice. These novel technologies are still largely in the research domain rather than recommended for routine use but provide a potential future opportunity to incorporate more primary prevention tailored advice. There are a number of online short courses available for primary healthcare professionals specifically focusing on skin cancer prevention. Most education and training programs for GPs and primary care nurses in the field of skin cancer focus on treatment and early detection, though some programs have specifically incorporated primary prevention education and training. A notable example is the Dermoscopy for Victorian General Practice Program, in which 93% of participating GPs reported that they had increased preventive information provided to high-risk patients and during skin examinations. Question 2 (related to barriers and enablers) Key enablers of performing skin cancer prevention activities in primary care settings included: • Easy access and availability of guidelines and point-of-care tools and resources • A fit with existing workflows and systems, so there is minimal disruption to flow of care • Easy-to-understand patient information • Using the waiting room for collection of risk assessment information on an electronic device such as an iPad/tablet where possible • Pairing with early detection activities • Sharing of successful programs across jurisdictions. Key barriers to performing skin cancer prevention activities in primary care settings included: • Unclear requirements and lack of confidence (self-efficacy) about prevention counselling • Limited availability of GP services especially in regional and remote areas • Competing demands, low priority, lack of time • Lack of incentives.