Добірка наукової літератури з теми "Bully target"
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся зі списками актуальних статей, книг, дисертацій, тез та інших наукових джерел на тему "Bully target".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Статті в журналах з теми "Bully target"
1
Donnery, Eucharia. "Deconstructing the Bully and Victim Dichotomy." Scenario: A Journal of Performative Teaching, Learning, Research IV, no. 2 (July 1, 2010): 22–43. http://dx.doi.org/10.33178/scenario.4.2.3.
Повний текст джерелаАнотація:
Although steps have been taken to address the issue of ijime or bullying, it remains is a serious social problem within the Japanese educational system. The main focus of this pilot study was to ascertain how beneficial process drama could be in developing oral communicative skills in the target language of English as well as to build social awareness through the deconstruction of the bully and victim dichotomy. Process drama in language acquisition is unique in its aim to fuse language learning and personal development. The average Japanese university student has had six years of compulsory English education, with an emphasis on grammar-translation and accuracy. This means that, while the average student excels at translation and test-taking, s/he has had little experience with communicative English and has no sense of ownership of the language. Because of this lack of oral communicative skills, process drama is an ideal means to build the bridge to communicative competence. This paper is part of a larger tri-semester process drama project and the data accumulated from all three will be used as evidence in a final PhD dissertation. Although steps have been taken to address the issue of ijime or bullying, it remains is a serious social problem within the Japanese educational system. The main focus of this pilot study was to ascertain how beneficial process drama could be in developing oral communicative skills in the target language of English as well as to build social awareness through the deconstruction of the bully and victim dichotomy. Process drama in language acquisition is unique in its aim to fuse language learning and personal development. The average Japanese university student has had six years of compulsory English education, with an emphasis on grammar-translation and accuracy. This means that, while the average student excels at translation and test-taking, s/he has had little experience with communicative English and has no sense of ownership of the language. Because of this lack of oral communicative skills, process drama is an ideal means to build the bridge to communicative competence. This paper is part of a larger tri-semester process drama project and the data accumulated from all three will be used as evidence in a final PhD dissertation.
2
Runions, Kevin C., Donna S. Cross, Rena Vithiatharan, Mark Everard, and Graham Hall. "Bullying and psychosocial adjustment among children with and without asthma." Journal of Psychologists and Counsellors in Schools 31, no. 1 (March 5, 2021): 36–45. http://dx.doi.org/10.1017/jgc.2020.32.
Повний текст джерелаАнотація:
AbstractChildren with asthma face serious mental health risk, but the pathways remain unclear. This study aimed to examine bullying victimisation and perpetration in children with asthma and a comparison sample without a chronic health condition, and the role of bullying in moderating psychosocial adjustment outcomes for those with asthma. A sample of children with (n = 24) and without asthma (n = 39), and their parents, were recruited from hospital clinics. Parents rated children’s psychosocial adjustment; children provided self-report of bullying victimisation and perpetration; from which co-occurring bully/victim status was derived. No differences in mean perpetration or victimisation were found, but children with asthma were more likely to be bully/victims (involved both as target and perpetrator), compared to those without asthma. Children with asthma who were victims of bullying had greater peer problems and overall adjustment problems; bully/victims did not show this pattern. Children with asthma may be more likely to be bully/victims, and those who are victims of bullying may be at elevated risk for psychosocial adjustment problems and require particular support in this area from school counsellors and psychologists.
3
Wang, Yong, and Carl Roberts. "Schadenfreude: A Case Study of Emotion as Situated Discursive Display." Comparative Sociology 5, no. 1 (2006): 45–63. http://dx.doi.org/10.1163/156913306776915597.
Повний текст джерелаАнотація:
AbstractMost Americans are aware that joy was expressed in the Arab world over the suffering inflicted on Americans with the September 11th attacks on the World Trade Center and Pentagon. Less known is that such Schadenfreude was expressed by many Chinese citizens as well. This paper analyzes a sample of texts from postings on the Beijing University bulletin board system. Following a discursive approach to the social psychological study of emotion, we consider discourse as the means whereby power relations are asserted and maintained. These power relations comprise a domain within which actions and emotional displays are occasioned and understood. Based on the texts analyzed here, Schadenfreude can be understood as a discursive display by an observer of an event. This event must be recognized in terms of a "discursive history" within which a bully (here, the United States) has repeatedly violated the "rights" of bullied parties. In accordance with this discursive history, the event is seen as a reversal-in-tradition whereby rights presumed by the bully are violated. Finally, the observer must disidentify with the bully. As a discursive display, Schadenfreude not only comprises the overt performance of the observer's taken-for-granted understanding of the bully-as-bully, but also displaces any potential alternative discourse such as expressions of sympathy other observers may have for any target of such an event. This approach complements the social constructionist perspective within the literature on the sociology of emotions, but departs fundamentally from this literature's essentialist (or psycho-physiological) perspective.
4
Blake, Jamilia J., Qiong Zhou, Oi-Man Kwok, and Michael R. Benz. "Predictors of Bullying Behavior, Victimization, and Bully-Victim Risk Among High School Students With Disabilities." Remedial and Special Education 37, no. 5 (August 2, 2016): 285–95. http://dx.doi.org/10.1177/0741932516638860.
Повний текст джерелаАнотація:
The literature on bullying among students with disabilities is burgeoning. The purpose of this study was to examine risk factors for adolescents’ involvement in bullying across the bullying continuum. Drawing from the National Longitudinal Transition Study–2 (NLTS2), 2,870 adolescents with disabilities were sampled. Results from multinomial regression analyses indicated that internalizing symptoms and interpersonal skills were significant predictors of victimization and bully-victimization risk, respectively. Disability status emerged as a significant predictor only for bullying behavior. Ethnic differences were found for victimization roles, but not for bullying, suggesting that Caucasian students were most vulnerable to being the target of bullying or serving dual roles as bully-victims relative to students from other ethnic backgrounds. Implications for these findings are discussed.
5
Dodge, Toby. "Chapter Six: From bully to target: Iraq's changing role in the Middle East." Adelphi Series 52, no. 434-435 (December 2012): 181–98. http://dx.doi.org/10.1080/19445571.2012.758342.
Повний текст джерела
6
Rohail, Iffat, Atteen Rohail, and Tayyaba Hanif. "Beggars as Bully Perpetrators and General Public as Victims." Foundation University Journal of Psychology 4, no. 1 (April 8, 2020): 34–61. http://dx.doi.org/10.33897/fujp.v4i1.62.
Повний текст джерелаАнотація:
This qualitative study aimed to explore peoples’ experiences of being bullied and victimized while dealing with beggars phenomenologically. 14 Adults (7 males, 7 females) were included in the study. The age of participants was 25 years and above. The main objectives of the study were to explore how beggars emotionally victimize the general public, how do people get threatened at the hands of beggars as they exploit the publics’ emotions with the help of blackmailing tactics Therefore the Research Questions in this regard were: firstly, how people are entangled in situations and feel threatened while interacting with beggars? Secondly, what tactics are used by beggars to emotionally victimize the general public? Thirdly, how public is emotionally blackmailed by the tricks and tactics used by beggars? Phenomenological research design was used which provided a rich and detailed account of public experiences. The focus was on how people actually perceived the events rather than how the phenomena existed. Open ended questions were put forth which provided the lived experiences of the participants. Responses of the participants were transcribed and themes were generated. The major themes which emerged were named as Anger, Exploitation, Distress, Manipulation, Fraud, Fear, Assault, Fooling public, Emotionally charging, Threatening, Stealing, Target weakness, Harassed, Monitory gain by beggars. Hence the results revealed that people do felt threatened while interacting with beggars who blackmailed them with different tricks and at times also involved in stealing, intimidation unwanted touching, name calling, cursing and even snatching the money from wallets, etc The implication of this study can be at societal or governmental level where authorities and policy makers can adopt some preventive or remedial measures for beggars and their interaction with public.
Key words: Perpetrators, Bully, Victim, General Public, Beggar, Phenomenological.
7
Zhang, Ketian. "Cautious Bully: Reputation, Resolve, and Beijing's Use of Coercion in the South China Sea." International Security 44, no. 1 (July 2019): 117–59. http://dx.doi.org/10.1162/isec_a_00354.
Повний текст джерелаАнотація:
Since 1990, China has used coercion in its maritime territorial disputes in the South China Sea, despite adverse implications for its image. China is curiously selective in its timing, targets, and tools of coercion: China rarely employs military coercion, and it does not coerce all countries that pose similar threats. An examination of newly available primary documents and hundreds of hours of interviews with Chinese officials to trace the decisionmaking processes behind China's use and nonuse of coercion reveals a new theory of when, why, and how China employs coercion against other states, especially in the South China Sea. Contrary to conventional wisdom, the findings show that China is a cautious bully that does not use coercion frequently. In addition, when China becomes stronger, it tends to use military coercion less often, choosing instead nonmilitary tools. Moreover, concerns with its reputation for resolve and with economic cost are critical elements of Chinese decisionmaking regarding the costs and benefits of coercing its neighbors. China often coerces one target to deter others—“killing the chicken to scare the monkey.” These findings have important implications for how scholars understand states' coercive strategies and the future of Chinese behavior in the region and beyond.
8
Pichel, Rafael, Mairéad Foody, James O’Higgins Norman, Sandra Feijóo, Jesús Varela, and Antonio Rial. "Bullying, Cyberbullying and the Overlap: What Does Age Have to Do with It?" Sustainability 13, no. 15 (July 30, 2021): 8527. http://dx.doi.org/10.3390/su13158527.
Повний текст джерелаАнотація:
School bullying and cyberbullying represent the most common forms of victimization during childhood and adolescence in many countries across the globe. Although they can be studied as distinct phenomena with their own defining characteristics, there is evidence to suggest that they are related and often co-occur. The present research aimed to estimate the rates of school bullying and cyberbullying, studied their evolution by age, and analyzed any possible overlap between the two. An empirical study was carried out with a large sample of children and adolescents in Galicia, Spain (N = 2083), where 10–17 year olds were presented with The European Bullying Intervention Project Questionnaire and European Cyberbullying Intervention Project Questionnaire. School bullying was found to be more prevalent than cyberbullying, with 25.1% involved as victims and 14.3% as bully-victims, while the cyberbullying rates were 9.4% for victims and 5.8% for bully-victims. Perpetration rates were similar for school and cyberbullying (4.4% and 4.3% respectively). The overlap between both phenomena adds to the evidence for a whole-community approach to tackling all types of bullying and victimization experiences, as opposed to each in silo. The clear age differences in bullying behaviours also suggest the appropriateness of tailoring anti-bullying programs to target specific age groups.
9
P Hollis, Leah. "The Abetting Bully: Vicarious Bullying and Unethical Leadership in Higher Education." Journal for the Study of Postsecondary and Tertiary Education 4 (2019): 001–18. http://dx.doi.org/10.28945/4255.
Повний текст джерелаАнотація:
Aim/Purpose: The purpose of this paper is to examine the phenomena of vicarious bullying, or an abetting bully, when a bully’s subordinate is used to inflict abuse on the target. This study examines who is most affected by this multi-faceted organizational abuse in American higher education. Background: Workplace bullying has received international attention. Recent studies in the United States have focused on workplace bullying in higher education. However, workplace bullying emerges from an elaborate social structure. This research article brings the unique perspective of vicarious bullying for analysis. Methodology: A data collection from 729 American higher education professionals was used to answer the following three research questions which were addressed in this study: RQ1: What is the overall prevalence of vicarious bullying in American higher education? RQ2: What is the likelihood of experiencing vicarious bullying in American higher education based on gender? RQ3: What is the likelihood of experiencing vicarious bullying in American higher education based on a woman’s race? A chi-square analysis was used to examine which demographic groups are more susceptible to vicarious bullying. Contribution: This article expands the literature on workplace bullying in American higher education by considering how unethical leadership can contribute to and inspire abetting and vicarious bullies who are enabled to maintain the toxic work culture. Findings: This article expands the literature on workplace bullying in American higher education by considering how unethical leadership can contribute to and inspire abetting and vicarious bullies who are enabled to maintain the toxic work culture. Recommendations for Practitioners: Vicarious bullying occurs when the organization fails to curtail managerial abuse. The result is higher turnover for women employees. Working with chief diversity officers and EEO officials can develop policies that stifle this behavior. Recommendation for Researchers: While workplace bullying has gained international attention, the organizational behavior of vicarious bullying is a unique organizational perspective that warrants further study. Impact on Society: Data confirm that women are more likely to leave their organizations to avoid workplace bullying. Women’s departures weaken an organization when they take their insight and knowledge with them. Future Research: Future research can consider the relationship between ethical leadership at the department level and executive level of higher education, and how that might have an impact on the prevalence of workplace bullying.
10
Stavinoha, Peter L., Cody Solesbee, Susan M. Swearer, Steven Svoboda, Laura J. Klesse, and Alice Ann Holland. "Risk Factors for Bullying Victimization in Children with Neurofibromatosis Type 1 (NF1)." Children 8, no. 2 (February 15, 2021): 145. http://dx.doi.org/10.3390/children8020145.
Повний текст джерелаАнотація:
Neurofibromatosis type 1 (NF1) is an autosomal disorder associated with numerous physical stigmata. Children with NF1 are at known risk for attention-deficit/hyperactivity disorder (ADHD), academic struggles, and significant social difficulties and adverse social outcomes, including bullying victimization. The primary aim of this study was to identify risk factors associated with bullying victimization in children with NF1 to better inform clinicians regarding targets for prevention and clinical intervention. Children and a parent completed questionnaires assessing the bully victim status, and parents completed a measure of ADHD symptoms. Analyses were completed separately for parent-reported victimization of the child and the child’s self-report of victimization. According to the parent report, results suggest ADHD symptoms are a significant risk factor for these children being a target of bullying. Findings for academic disability were not conclusive, nor were findings related to having a parent with NF1. Findings indicate the need for further research into possible risk factors for social victimization in children with NF1. Results provide preliminary evidence that may guide clinicians working with children with NF1 and their parents in identifying higher-risk profiles that may warrant earlier and more intensive intervention to mitigate later risk for bullying victimization.
Дисертації з теми "Bully target"
1
Simmons, Don. "Victims' Perspectives of Management's Interventional Efforts Regarding Relational Aggression in the Workplace." ScholarWorks, 2018. https://scholarworks.waldenu.edu/dissertations/5781.
Повний текст джерелаАнотація:
Relational aggression (RA) is a social phenomenon that can severely impact organizational profitability and employee productivity. A gap in the literature exists concerning appropriate interventions to manage RA. The purpose of this study was to explore successful interventions that have been used to manage RA. The theoretical framework was informed by psychological contract theory. Data were collected via semistructured face-to-face interviews with 12 victims, and then analyzed using data management, reading and memorization, description, classification, interpretation, and representation. NVivo software was used to organize the data in this study. The research consisted of 3 subquestions addressing the role of written policies in interventions, common practices and reactions of management, and victims' requests for attention to grievance reports. Five key themes emerged. The first and second pertain to the proactive and reactive role of written policies. The third and fourth focus on management's negative and positive reactions in response to grievance reports. The fifth identifies victims' expectations for their grievance reports. Commonly found interventions include impartially listening to both sides, investigation, restoration of damages, social justice, and identifying root causes for RA in the workplace. Implications for positive social change include enhanced employee well-being and performance and increased organizational effectiveness. Results may lead to positive changes by providing useful information that can be implemented by organizations to prevent and address RA, which can improve employee well-being.
2
Beckford, Nina A. "Bullies and Bystanders." University of Toledo / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1431627347.
Повний текст джерела
3
Kobzová, Lucie. "Návrh na zlepšení marketingového řízení firmy Red bull." Master's thesis, Vysoké učení technické v Brně. Fakulta podnikatelská, 2008. http://www.nusl.cz/ntk/nusl-376774.
Повний текст джерелаАнотація:
My master’s thesis from marketing area is focused on marketing management of Red Bull Company, which is world leading energy drink producer. My work should improve marketing management of the firm and suggest new ways of marketing communication, the way of addressing consumers and non-consumers of Red Bull energy drink. The results of this master’s thesis will be suggested to the management of Red Bull Company for implementation into praxis.
4
Cooney, Lucretia. "BULLYING: OUT OF THE SCHOOL HALLS AND INTO THE WORKPLACE." Master's thesis, University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2676.
Повний текст джерелаАнотація:
The primary purpose of this study is to identify those people at most risk of being bullied at work. While much research is being conducted on school bullying, little has been conducted on workplace bullying. Using data gathered from a 2004 study conducted by the National Opinion Research Center for the General Social Survey, which included a Quality of Work Life (QWL) module for the National Institute for Occupational Safety and Health (NIOSH), linear regressions indicated significant findings. As predicted, workers in lower level occupations, as ranked by prestige scoring developed at National Opinion Research, are more likely to be victimized. Data also suggest that being young, Black, and relatively uneducated may contribute to being bullied in certain situations. Future research is needed to examine influences of socio-economic, legal, and other demographic factors that may predict the chance of being bullied.M.A.
Department of Sociology
Sciences
Applied Sociology MA
5
Jenkins, Moira Fay. "Workplace bullying: the perceptions of the target, the alleged perpetrator and the HR professional: integrating stakeholders’ voices to improve practice and outcomes." Thesis, 2011. http://hdl.handle.net/2440/68744.
Повний текст джерелаАнотація:
Through three exploratory studies encompassing different stake-holder perspectives, this thesis examines what happens when people complain about workplace bullying. In the first study, thirty one participants who had submitted formal complaints described a wide range of negative workplace behaviours as bullying, and all reported detrimental psychological and physical consequences as a result. Perceptions of unfairness was a major theme to emerge from the interviews, as was the importance of complainants validating their experience and obtaining justice through legal and other types of advocacy. Sixty-three per cent of complainants submitted a workers' compensation claim as a result of bullying and an accepted workers' compensation claim was viewed as validating their perception of the bullying. Thirty accused bullies participated in the second study. Antecedents to the workplace bullying complaints were similar to those found in studies of bullied targets. Many participants viewed themselves as victims of bullying by their staff and others defended their behaviour as legitimate performance management techniques. The accused bullies reported negative psychological health outcomes in terms of depression, anxiety, post-traumatic stress and suicidal ideation, irrespective of whether they had been found guilty of bullying or not. The third study examined the bullying complaint process from the perspective of the human resources' (HR) consultant, using focus groups. The main themes to emerge were the framing of bully complaints as conflicts, a push to manage bully complaints through conflict management and conciliatory processes and the lack of follow-up after complaint resolution. These results are discussed in light of the negative perception of fairness that a conflict-management perspective could have for complainants who believe their bullying allegations have not been taken seriously by the organisation. Overall, results highlight the subjective nature of the term bullying and suggest that a perception of injustice is central to an understanding of workplace bullying. The way that a bullying complaint is framed and managed by HR personnel can serve to exacerbate this sense of unfairness. These studies break the long tradition of primarily only listening to the victims' perspective in work-place bullying research.Thesis (Ph.D.) -- University of Adelaide, School of Psychology, 2011
Книги з теми "Bully target"
1
Lyman, Howard F. No more bull!: The mad cowboy targets America's worst enemy--our diet. New York: Scribner, 2005.
Знайти повний текст джерела
2
Sandler, Corey. Official Sega Genesis and Game Gear strategies, 3RD Edition. New York: Bantam Books, 1992.
Знайти повний текст джерела
3
Tom, Badgett, ed. Official Sega Genesis and Game Gear strategies, 2ND Edition. Toronto: Bantam Books, 1991.
Знайти повний текст джерела
4
Mcdermott, Leeanne. GamePro Presents: Sega Genesis Games Secrets: Greatest Tips. Rocklin: Prima Publishing, 1992.
Знайти повний текст джерела
5
Centrone, Terry. How Not to Be a Bully Target. YouthLight, 2007.
Знайти повний текст джерела
6
Centrone, Terry. How Not to Be a Bully Target. YouthLight, 2007.
Знайти повний текст джерела
7
How Not to Be a Bully Target. YouthLight, 2007.
Знайти повний текст джерела
8
Sims, KIamesha Denise. Targets: Part 1 of the Blinded Bulls Eye Series:. Independently Published, 2020.
Знайти повний текст джерела
9
Nanayakkara, Fiona. Bully & Co: Managing Bullies and Coping Strategies for Targets Harassed at Work. Independently Published, 2018.
Знайти повний текст джерела
10
Nanayakkara, Fiona. Bully and Co: Managing Bullies and Coping Strategies for Targets Harassed at Work. Independently Published, 2018.
Знайти повний текст джерелаЧастини книг з теми "Bully target"
1
Oade, Aryanne. "Sowing The Seeds for Bullying: The First Interactions Between a Bully and Their Target." In Managing Workplace Bullying, 35–50. London: Palgrave Macmillan UK, 2009. http://dx.doi.org/10.1057/9780230249165_3.
Повний текст джерела
2
Simmons, Janelle Christine. "Overcoming the Onslaught." In Confronting Academic Mobbing in Higher Education, 1–28. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-5225-9485-7.ch001.
Повний текст джерелаАнотація:
This chapter seeks to explore and examine the phenomenon known as mobbing and more specifically academic mobbing. First, a brief introduction to bullying at the workplace as well as mobbing ensues. Second, the definitions of mobbing and academic mobbing as well as clear descriptions are delineated. Third, various topics surrounding academic mobbing are introduced such; the phases of mobbing, a description of the bully, a description of the “mobbers,” a description of the bystanders and a description of the target. Other topics are introduced as well such as statistics that surround the phenomenon of mobbing at the workplace as well as workplace engagement results of academic mobbing. Then the methodology is introduced. This research study is qualitative in nature. An autoethnography is utilized and the data is seen through a constructivist/interpretivist lens. The author than introduces her experience via narrative form, which is followed by a discussion and conclusion, limitations of the study, recommendations for future research, and a statement of conflict.
3
"Status, Distribution, and Conservation of Native Freshwater Fishes of Western North America." In Status, Distribution, and Conservation of Native Freshwater Fishes of Western North America, edited by Keith Underwood and Steve P. Cramer. American Fisheries Society, 2007. http://dx.doi.org/10.47886/9781888569896.ch18.
Повний текст джерелаАнотація:
ABSTRACT A life cycle model was employed to identify the response of an adfluvial bull trout <em>Salvelinus confluentus</em> population to chronic and catastrophic losses of subadults. The model simulates the bull trout population within Rimrock Lake, Washington, a reservoir on the Tieton River impounded by Tieton Dam. Subadult bull trout are entrained during summer water releases for irrigation, and the dam has no fish passage facilities to enable those fish to return upstream. Suitable spawning and rearing habitat is primarily upstream of the dam. Tagging studies of adult bull trout passing weirs in the two major tributaries to the reservoir were used to estimate model parameters for survival, maturity rates, reproductive capacity, and initial abundance. Sampling data and the deterministic model simulations indicated that the population was capable of rebounding quickly from intermittent catastrophic events. Resilience of the bull trout population resulted from high adult longevity and repeat spawning. The accumulation of mature adults across multiple age-classes led to egg deposition that fully seeded rearing capacity of the natal tributaries, even when several consecutive broods of juveniles exhibited poor survival. Catastrophic events simulated to entrain 50% of the subadults every 15 years caused a 40% reduction in adult abundance within 4 years of the event, followed by a full recovery to maximum production within 9 years. Even during the low point of adult abundance, 15 times more eggs were deposited than were needed to fully seed juvenile tributary habitat. Because the population was already producing juveniles at capacity, simulations for opening fish passage over Rimrock Dam showed that the sustained spawner population would increase by only two adults. However, simulations for expanded juvenile habitat by 14% indicated that the sustainable adult population would increase by 14%. Thus, habitat improvements that target juvenile rearing capacity appear to have the greatest potential to increase population size.
4
Mcguinness, Victoria. "Play Therapy Targets for EMDR Processing: How to Get a “Bulls-Eye”." In EMDR With Children in the Play Therapy Room. New York, NY: Springer Publishing Company, 2020. http://dx.doi.org/10.1891/9780826175939.0019.
Повний текст джерела
5
Pérez-Pariente, Joaquín, Raquel García, Ana B. Pinar, Luis Gómez-Hortigüela, Enrique Sastre, and Carlos Márquez-Alvarez. "Synthesis of open zeolite frameworks by using a combination of bulky and cage-forming structure directing agents." In Zeolites and related materials: Trends, targets and challenges, Proceedings of the 4th International FEZA Conference, 135–40. Elsevier, 2008. http://dx.doi.org/10.1016/s0167-2991(08)80164-4.
Повний текст джерела
6
Taber, Douglass F. "The Garg Synthesis of (–)-N-Methylwelwitindolinone C." In Organic Synthesis. Oxford University Press, 2015. http://dx.doi.org/10.1093/oso/9780190200794.003.0089.
Повний текст джерелаАнотація:
Of the several welwitindolinones, (–)-N-methylwelwitindolinone C 3 uniquely reverses P-glycoprotein-mediated multiple drug resistance. The preparation of 3 reported (J. Am. Chem. Soc. 2011, 133, 15797) by Neil K. Garg of UCLA illustrates the power in complex target-directed synthesis of late stage C–H functionalization. The starting material 7 for this enantiospecific synthesis was prepared following the Natsume strategy (Chem. Pharm. Bull. 1994, 42, 1393) in the enantiomeric series. Commercial carvone 4 was reduced and protected, then oxidized and equilibrated to the dienone 6. The pivalate efficiently directed the Cu-catalyzed conjugate addition of vinyl magnesium bromide, delivering 7. Hydrolysis of 7 gave 8, to which the bromoindole 9 was added in a conjugate sense to give the adduct as a mixture of diastereomers, of which 1 was the more stable. Exposure of 1 to NaNH2 in t-BuOH presumably generated the benzyne [indolyne] 10, which cyclized to the ketone 2. The silyl ether 2 was deprotected and the alcohol was oxidized to give the diketone, which was selectively carried on to the enol triflate and thus to the stannane 11. The alkenyl chloride of the natural product was installed by the oxidation of 11 with CuCl2. Further oxidation with N-bromosuccinimide then delivered the oxindole 12. In the last stage of the synthesis, it was necessary to selectively aminate one of the bridgehead C–H’s of 12. To this end, the ketone was reduced and carried on to the carbamate 13. Attempts to oxidatively cyclize 13 with Rh catalysts failed, but Ag was successful, delivering 14. The final conversion of 15 to (–)-N-methylwelwitindolinone C 3 was achieved by exposure to the Kim reagent 16.
7
"Shark Nursery Grounds of the Gulf of Mexico and the East Coast Waters of the United States." In Shark Nursery Grounds of the Gulf of Mexico and the East Coast Waters of the United States, edited by JOHN K. CARLSON. American Fisheries Society, 2007. http://dx.doi.org/10.47886/9781888569810.ch18.
Повний текст джерелаАнотація:
<em>Abstract.</em>—A dynamic mass-balance ecosystem model (Ecopath with Ecosim) was used to investigate how relative changes in fishing mortality on sharks can affect the structure and function of Apalachicola Bay, Florida, a coastal marine ecosystem. Simulations were run for 25 years, wherein fishing mortality rates from recreational and trawl fisheries were doubled for 10 years and then decreased to initial levels. Effect of time/area closures on ecosystem components were also tested by eliminating recreational fishing mortality on juvenile blacktip sharks <em>Carcharhinus limbatus</em>. Simulations were run assuming mixed control and top-down control. In the mixed control, biomass of juvenile coastal sharks (finetooth shark <em>C. isodon</em>, spinner shark <em>C. brevipinna</em>, sandbar shark <em>C. plumbeus</em>), juvenile blacktip sharks, and bull sharks <em>C. leucas </em>declined up to 57% when recreational fishing mortality was doubled. Increases in biomass were also observed for the Atlantic sharpnose shark <em>Rhizoprionodon terraenovae </em>and, to a lesser extent, skates and rays. Increasing the fishing mortality imposed by trawl fisheries affected only a few elasmobranch groups, primarily skates and rays. Increases and decreases in biomass lasted only as long as fishing mortality was elevated, although a lag time was observed for some groups to recover to initial biomass. Simulating a time/ area closure for juvenile blacktip sharks caused increases in their biomass but decreases in juvenile coastal shark biomass, a competing multispecies assemblage that is the apparent competitor. Topdown control scenarios resulted in greater variation and magnitude of response than those elicited under mixed control, although the direction of the response was similar. In general, reduction of targeted sharks did not cause strong top-down cascades.
Тези доповідей конференцій з теми "Bully target"
1
Legault, Jean M., Marta Orta, Harish Kumar, and Shengkai Zhao. "ZTEM and VTEM airborne EM survey results over PGM‐Cu‐Ni targets at East Bull Lake anorthositic complex, Massey, Ontario." In SEG Technical Program Expanded Abstracts 2011. Society of Exploration Geophysicists, 2011. http://dx.doi.org/10.1190/1.3628158.
Повний текст джерела
2
Oh, JongSik, and HeonSeok Lee. "Development of High-Speed Industrial Turbo Blowers With Foil Air Bearings." In ASME Turbo Expo 2003, collocated with the 2003 International Joint Power Generation Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/gt2003-38606.
Повний текст джерелаАнотація:
In the paper, the development of high-speed industrial turbo blowers with foil air bearings is presented as a first successful commercialization in the world. Their target market is various from wastewater treatment to cement factory processes which require compressed air ranging between 0.6 and 0.8 bar gauge. Employing the state-of-the-art technology of the high-speed BLDC motors, the bump-type foil air bearings and the high-efficient turbo impellers/diffusers, so much compact, efficient and silent blower machines of a single stage are now available in the market, aiming to replace the existing inefficient, bulky and noisy ones, such as roots blowers. The first production lines are established for 75 and 150 hp class blowers. Rotational speeds up to 40,000 rpm are realized directly from the high-speed BLDC motors without any gear boxes, and no lubrication oil is required. A brief introduction of design, manufacture and test results is presented for mechanical, electrical and aerodynamic performance.
3
Soudarev, A. V., and A. S. Molchanov. "Development of Express Calculation-Experimental Technique to Estimate Life and Reliability of Ceramic Parts and Components." In ASME Turbo Expo 2004: Power for Land, Sea, and Air. ASMEDC, 2004. http://dx.doi.org/10.1115/gt2004-54188.
Повний текст джерелаАнотація:
The analysis of existing programs to develop advanced ceramic gas turbine engines indicates that the challenge to ensure a target life of ceramic components is of a paramount importance. The up-to-date express methodologies to define life have some principal limitations which necessitates to carry out labor- and time-consuming tests of bulky batches of ceramic samples and parts. The accuracy of the predicted results, at the same time, remains rather low which does not allow their practical application to design ceramic parts and components. An improvement of techniques of the life estimation could be attained considering that a crack growth takes place under load, this phenomenon occurring with the crack shear stress generation, this stress correlating with a threshold value of the stress intensity factor. It turns out here that along with the dynamic failure, the test duration is also a significant parameter, i.e. the parameter which is neglected by the current methodology to estimate the static failure and life. The developed methodology demonstrates not a bad correlation between the estimates and the experimental values, whereby reducing the scope of the initial data compared with the current methodology. Furthermore, using this approach one can predict results of proof tests which enables opting for an optimum proof duty. A result of the proof tests is essentially dependent on three test condition parameters, namely: 1. The value of a selected trial loading or a fraction of the parts rejected; 2. The exposition time under the trial loading; 3. The test temperature and the initial scatter of the strength properties. The sequence of the calculation carrying out is as follows: 1. A required Weibull modulus is identified using the static failure estimate technique for a target reliability of the ceramic element, stresses under the operation conditions, operation time, dynamic failure parameters. 2. The proof test conditions are identified using the Weibull modulus required. The obtained calculation formulae need a smaller scope of the experimental data with the static failure accuracy and life becoming greater compared with the existing values. Thus, the methodology presented allows to ensure a target reliability of ceramic parts, to identify their quantity required and the preliminary tests conditions.
4
Foucher, Pierre, Anand Raghavan, Todor Sheiretov, David Engel, Christopher Babin, Josh Wurtz, Hayden Melvin, and Francisco Garzon. "Sand Control Screen Clogging Remediation with Innovative High-Density Slot Machining Solution." In SPE/ICoTA Well Intervention Conference and Exhibition. SPE, 2022. http://dx.doi.org/10.2118/209031-ms.
Повний текст джерелаАнотація:
Abstract A gravel pack equipped with sand screen completion is commonly used in deepwater Gulf of Mexico. Over time, fines migration and asphaltenes clog the screens of the completion, which negatively affects the well production. In order to remediate the damage, openings are created in the concentric base pipe inside the screen (Fig. 1). This process creates a flow path that allows for cleaning of debris from the screens through jetting and bull heading of stimulation fluids. The combination of these operations restores the productivity of the well. In the conventional method, the cuts are machined one at a time with a blade spinning in the horizontal plane. To achieve sufficient flow area, this step is repeated approximately hundred times to distribute the cuts along the target screen interval. Such an operation can require up to 14 days including the downhole cutting time as well as trips in and out of the well to replace the blades. The blades protrude only slightly from the base pipe to avoid damaging the screen. The screens are separated from the base pipe with standoff to maintain a constant clearance. Thus, the blades cannot damage the screen.
5
Mohd Shafian, Siti Rohaida, Benayad Nourreddine, Nur Atiqah Zakaria, Nik Nor Azrizam Nik Norizam, Noorazlenawati Borhan, M. Shakir M Nawi, M. Haziq Farhan M Zaki, et al. "Pilot Application of a Novel Nano-Clay Relative Permeability Modifier in a Mature Malaysian Offshore Oilfield." In SPE/IATMI Asia Pacific Oil & Gas Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/205580-ms.
Повний текст джерелаАнотація:
Abstract Excessive water production associated with a decrease in hydrocarbon production is becoming a big challenge in matured offshore fields. Producing a barrel of water requires more energy that creates major economic impact on the profitability of an oil-field project. This paper presents a case study for water shut off treatment with a novel relative permeability modifier (RPM) (nano-clay). The nano-clay demonstrated high resistance to water flow (RRFw >10) and less effect to oil flow (RRFo <5) and capable to change the rock surface's wettability to more water wet. The main pilot objective was to assess the chemicals performance as part of production enhancement effort to reduce the water production from 90% to 50% water cut and to accelerate the oil production. We discussed the overall workflow, pilot execution, challenges and best practices including the laboratory results with the reference during research and development stage. The well treatment consists of bull-heading a pill of pre-flush of treated sea water for injectivity test, followed by nano-clay injection, post-flush with treated sea water, soaking for 48 hours and flow back the well. Pilot execution was completed successfully and safely within the target execution plan and are currently in monitoring stage. The post-treatment results and the overall economic success will then decide the future replication plan of this new water shut off technology.
6
Cavallaro, Alberto, and Laxman Saggere. "Picoliter Fluidic Flow Characterization Using Ion-Selective Measurement." In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-82646.
Повний текст джерелаАнотація:
Techniques for accurate measurement of liquid flows involving volumes on the order of nanoliters and picoliters are critical for advancement of microfluidics applications. Although several techniques for measurement of microfluidic flows where a liquid is dispensed on to a target are available today, no proven techniques currently exist for measurement of microfluidic flows where a liquid is injected into a liquid media. Motivated by such a measurement need in a current project, this paper presents a novel experimental technique to measure bulk-flow of a liquid dispensed into another liquid medium with sensitivity down to picoliter range. This technique is based on the principle of titration of two liquids and measurement of hydrogen ions in the resulting solution. The critical components of the system that enable the proposed technique are: A highly sensitive hydrogen ion concentration (pH) sensor and a device to dispense very small, calibrated, volumes of liquid. Since commercially available hydrogen ion sensors are bulky for use in the proposed technique, a hydrogen ion sensor element that provides a sensing tip dimension on the order of a few microns is fabricated from a glass capillary for the current study. Dispensing of calibrated volumes of liquid is accomplished by means of a calibrated syringe for volumes in nanoliter range and a glass capillary for volumes in picoliter range, the latter serving as a dispensing port of a diameter of about 2 μm. The paper includes details of experiments where the proposed technique is first applied to precisely predict injections of 20 and 40 nL volumes and then extended to demonstrate the sensitivity of the sensor element to injections of volumes in the picoliter range. The preliminary experimental results presented generally validate the principle involved in this technique and suggest that the technique is virtually scalable to any volume flows typically encountered in the microfluidics applications.
7
Sinha, Ashish, and Yogendra Joshi. "Performance of Thermoelectric Based Regenerative Adsorption Cooling System for Harsh Environment." In ASME 2009 International Mechanical Engineering Congress and Exposition. ASMEDC, 2009. http://dx.doi.org/10.1115/imece2009-12655.
Повний текст джерелаАнотація:
Performance of a cooling system designed for thermal management of harsh environment electronics has been presented. The system is based on regenerative adsorption-desorption cycle and mainly comprises of two beds with zeolite-water as adsorbent-adsorbate pair, a condenser and an evaporator. Heat regeneration was achieved by a thermoelectric (TE) device placed in between the zeolite beds. Use of a thermoelectric device for heat transfer in between beds allows for miniaturization of usually bulky adsorption cooling systems. This also provides a cooling system with nearly no moving parts, hence suitable for harsh environment electronic cooling applications. Zeolite beds alternately carry out adsorption and desorption depending on the direction of heat flow in between them. Direction of heat flow is governed by the polarity of voltage applied across the TE device. Polarity is switched at fixed time intervals that determine the cycle time. Tests were carried out during which the condenser temperature hovered around 165 °C, heat load was up to 5W, the cycle time kept close to 12 minutes and the targeted evaporator temperature was 140 °C. System was analyzed in terms of the extent of cooling below the heat rejection ambient temperature of 160 °C and coefficient of performance. A COP of 0.2 was obtained. The study could be used to extend the working envelopes of existing electronics towards hotter surroundings. A mathematical model was also prepared and the experimental results have been compared with the simulations.
8
Prost, Victor, Kathryn M. Olesnavage, and Amos G. Winter. "Design and Testing of a Prosthetic Foot Prototype With Interchangeable Custom Rotational Springs to Adjust Ankle Stiffness for Evaluating Lower Leg Trajectory Error, an Optimization Metric for Prosthetic Feet." In ASME 2017 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/detc2017-67820.
Повний текст джерелаАнотація:
A prosthetic foot prototype intended for evaluating a novel design objective for passive prosthetic feet, the Lower Leg Trajectory Error (LLTE), is presented. This metric enables the optimization of prosthetic feet by modeling the trajectory of the lower leg segment throughout a step for a given prosthetic foot and selecting design variables to minimize the error between this trajectory and target physiological lower leg kinematics. Thus far, previous work on the LLTE has mainly focused on optimizing conceptual foot architectures. To further study this metric, extensive clinical testing on prototypes optimized using this method has to be performed. Initial prototypes replicating the LLTE-optimal designs in previous work were optimized and built, but at 1.3 to 2.1 kg they proved too heavy and bulky to be considered for testing. A new, fully-characterized foot design reducing the weight of the final prototype while enabling ankle stiffness to be varied is presented and optimized for LLTE. The novel merits of this foot are that it can replicate a similar quasi-stiffness and range of motion of a physiological ankle, and be tested with variable ankle stiffnesses to test their effect on LLTE. The foot consists of a rotational ankle joint with interchangeable U-shaped constant stiffness springs ranging from 1.5 Nm/deg to 16 Nm/deg, a rigid structure extending 0.093 m from the ankle-knee axis, and a cantilever beam forefoot with a bending stiffness of 16 Nm2. The prototype was built using machined acetal resin for the rigid structure, custom nylon springs for the ankle, and a nylon beam forefoot. In preliminary testing, this design performed as predicted and its modularity allowed us to rapidly change the springs to vary the ankle stiffness of the foot. Qualitative feedback from preliminary testing showed that this design is ready to be used in larger-scale studies. In future work, extensive clinical studies with testing different ankle stiffnesses will be conducted to validate the optimization method using the LLTE as a design objective.
9
Saidu Mohamed, Anwarudin, Syafiq Effendi Jalis, Intiran Raman, Kumanan Sanmugam, Dhanaraj Turunawarasu, Mohd Firdaus Samsudin, Al Ashraf Zharif Al Bakri, and Kassim Selamat. "Restoring Technical Potential of Deep-Water Well Impaired by Hydrate Plug Embedded with Wax Deposit with Improved Characterization and Innovative Chemistry." In Offshore Technology Conference. OTC, 2021. http://dx.doi.org/10.4043/31232-ms.
Повний текст джерелаАнотація:
Abstract Hydrate occurrence is synonymous in deep water wells, notably when the well experience significant reduction in fluid temperature during production. Hence, the operating philosophy must take into consideration the ability to maintain the well-fluid outside the hydrate or wax phase envelope and ensure the contingencies are in place to mitigate any plug, deposit or gel formation. This paper illustrates the characterization of hydrate and wax plug encountered and devise of innovative solution to remediate the blockage in two wells in Sabah waters which were plugged due to cooling of the wells during an unplanned shut down. The solution devised is to set precedence to manage temperature dependent blockages in similar Deepwater wells or facilities. Hydrate and wax models were created to predict blockage severity and its location. Nodal analysis was used to model thermodynamic equilibrium at target location of the plug where the temperature is below the melting point and ultimately to predict the required heat to dissolve the blockages. A Thermo-chemical system was identified, selected, and customized and then injected into well to ensure the temperature generated at the location of the plug was above the melting point of hydrate and wax. Thermo-chemical injection was identified as a viable method of In-situ Heat Generating Technique to generate heat at desired location. The chemical solution was injected via capillary tubing to transmit the heat via conduction and convection to melt the hydrate and paraffinic plug in these 2 wells. An arriving temperature of 40°C at the target zones was required to melt the plug. A positive pressure was maintained in the production tubing during chemical injection to avoid rapid pressure increase as the hydrate plugs dissolved. A temperature of 100 °C was recorded at the wellhead throughout the injection. The downhole gauge indicated positive response, suggesting the heat generated transmitted effectively. After a short duration of injection, communication was established. Hydrate inhibitor was injected to secure the well prior to unloading. The wells were successfully relieved and stabilized production of 1,200 bopd and 800 bopd respectively. The simulation was redesigned based on data collected from the operation to improve the model and to be used for future works. The ability to integrate laboratory analysis, computer aided simulation and operational data was integral to this paper demonstrating an effective way to characterize temperature dependent blockages in production system. Design of experiments provided better insight to address the problem. Innovative use of novel chemistry to produce heat, in-situ heat solved hydrate and wax related issues in a most cost-effective manner. The process of customizing a chemical system based on laboratory and simulation results was effective in ensuring delivery of the results. The bull-heading operation to inject the chemical system proved to be a cost-effective remedial method to unlock the barrels and can be considered preventive or as a contingency measure in dealing with temperature dependent blockages or plugs in future.
10
Bassett, Michael, Ian Reynolds, Adrian Cooper, Simon Reader, and Martin Berger. "Modular Hybrid Powertrain Concept." In FISITA World Congress 2021. FISITA, 2021. http://dx.doi.org/10.46720/f2020-adm-070.
Повний текст джерелаАнотація:
Vehicle manufacturers are facing increasing pressure by legislation and economics to reduce vehicle emissions and deliver improved fuel economy. Over the coming years, significant reductions in carbon dioxide (CO2) emissions need to be achieved to meet fleet targets, whilst at the same time satisfying the more stringent forthcoming Euro7 emissions regulations. This focus on techniques to reduce the tailpipe CO2 is increasing the interest in hybrid and electric vehicle technologies. Pure electric vehicles require bulky and expensive battery packs, with a high embedded CO2 content, to enable an acceptable driving range. Range Extended Electric Vehicles (REEVs) partly overcome the limitations of current battery technology by having a range extender (REx) unit that allows a reduction of the traction battery storage capacity, whilst still maintaining an acceptable vehicle driving range. Building on previous research projects, focused on Rex and heavily downsized internal combustion engines, MAHLE have designed a plug-in hybrid driveline in which the systems have been fully integrated and optimised. The hybrid drive-line features a cost effective and high-efficiency, Miller-cycle, turbocharged, two-cylinder gasoline engine, with external exhaust gas re-circulation (EGR) and a pre-chamber combustion system, achieving over 40% brake thermal efficiency from a very low-cost architecture. This compact engine is combined with an electric traction system which can satisfy the full-dynamic requirements of the vehicle, even during pure-electric operation. The internal combustion engine can be operated in either series hybrid, or direct drive modes, via a compact multi-speed transmission. The paper will present the key features of the hybrid drivetrain and will describe the various modes of operation in the vehicle. Results of testing to validate the pre-chamber combustion system, coupled with a very high geometric compression ratio (CR) and external cooled EGR, will also be presented to support the efficiency claims made in the paper. Drive-cycle analysis, based on the engine test results, will also be used to show the efficiency of the entire system. Finally, the paper will present the scalability of the concept across a range of vehicle classes and performance levels.
Звіти організацій з теми "Bully target"
1
Boyle, Maxwell, and Elizabeth Rico. Terrestrial vegetation monitoring at Timucuan Ecological and Historic Preserve: 2019 data summary—Version 2.0. National Park Service, February 2022. http://dx.doi.org/10.36967/nrds-2290196.
Повний текст джерелаАнотація:
The Southeast Coast Network (SECN) conducts long-term terrestrial vegetation monitoring as part of the nationwide Inventory and Monitoring Program of the National Park Service (NPS). The vegetation community vital sign is one of the primary-tier resources identified by SECN park managers, and it is currently conducted on 15 network parks (DeVivo et al. 2008). Monitoring plants and their associated communities over time allows for targeted understanding of ecosystems within the SECN geography, which provides managers information about the degree of change within their parks’ natural vegetation. 2019 marks the first year of conducting this monitoring effort on four SECN parks, including Timucuan Ecological and Historic Preserve (TIMU). A total of 23 vegetation plots were established in the park in May and June. Data collected in each plot include species richness across multiple spatial scales, species-specific cover and constancy, species-specific woody stem seedling/sapling counts and adult tree (greater than 10 centimeters [3.9 inches (in)]) diameter at breast height (DBH), overall tree health, landform, soil, observed disturbance, and woody biomass (i.e., fuel load) estimates. This report summarizes the baseline (year 1) terrestrial vegetation data collected at Timucuan Ecological and Historic Preserve in 2019. Data were stratified across three dominant broadly defined habitats within the park (Coastal Plain Nonalluvial Wetlands, Coastal Plain Open Uplands and Woodlands, and Maritime Upland Forests and Shrublands) and three land parcels (Cedar Point, Theodore Roosevelt, and Thomas Creek). Noteworthy findings include: A total of 157 vascular plant taxa (species or lower) were observed across 23 vegetation plots, including nine species not previously known from the park. Three plots were located in the footprint of the Yellow Bluff Fire, and were sampled only two weeks following the fire event. Muscadine (Muscadinia rotundifolia), cat greenbrier (Smilax glauca), water oak (Quercus nigra), and swamp tupelo (Nyssa biflora) were the most frequently encountered species in Coastal Plain Nonalluvial Wetland habitat; saw palmetto (Serenoa repens), slash pine (Pinus elliottii), and gallberry (Ilex glabra) were the most frequently encountered species in Coastal Plain Open Upland and Woodland habitat; and Darlington oak (Quercus hemisphaerica), Spanish moss (Tillandsia usenoides), and red bay (Persea borbonia) were the most frequently encountered species in Maritime Upland Forests and Shrublands. There were no exotic species of the Florida Exotic Pest Plant Council list of invasive plants (FLEPPC 2020) observed on any of these plots. Both red bay and swamp bay (Persea palustris) were largely absent from the tree stratum in these plots; however, they were present (occasionally in high abundance) in the seedling and sapling strata across all habitat types. Buckthorn bully (Sideroxylon lycioides)—listed as Endangered in the state of Florida by the Florida Department of Agriculture and Consumer Services (FDACS 2020)—was observed in three Maritime Upland Forest and Shrubland plots. The tree strata in each broadly defined habitat were dominated by the following species: Coastal Plain Nonalluvial Wetlands-loblolly bay (Gordonia lasianthus) Coastal Plain Open Uplands and Woodlands-longleaf pine (Pinus palustris) Maritime Upland Forests and Shrublands-oaks (Quercus sp.) Most stems within the tree strata exhibited healthy vigor and only moderate dieback across all habitat types. However, there was a large amount of standing dead trees in plots within Maritime Upland Forests and Shrublands. Downed woody biomass (fuel loads) were highest in the Cedar Point and Thomas Creek land parcels.
2
Medrano, Juan, Adam Friedmann, Moshe (Morris) Soller, Ehud Lipkin, and Abraham Korol. High resolution linkage disequilibrium mapping of QTL affecting milk production traits in Israel Holstein dairy cattle. United States Department of Agriculture, March 2008. http://dx.doi.org/10.32747/2008.7696509.bard.
Повний текст джерелаАнотація:
Original objectives: To create BAC contigs covering two QTL containing chromosomal regions (QTLR) and obtain BAC end sequence information as a platform for SNP identification. Use the SNPs to search for marker-QTL linkage disequilibrium (LD) in the test populations (US and Israel Holstein cattle). Identify candidate genes, test for association with dairy cattle production and functional traits, and confirm any associations in a secondary test population. Revisions in the course of the project: The selective recombinant genotyping (SRG) methodology which we implemented to provide moderate resolution QTL mapping turned out to be less effective than expected, due to problems introduced by incomplete marker informativity. This required a no-cost one-year extension of the project. Aside from this, the project was implemented essentially as envisaged, but only with respect to a single QTLR and single population association-test. Background to the topic. Dairy cattle breeders are looking to marker-assisted selection (MAS) as a means of identifying genetically superior sires and dams. MAS based on population-wide LD can be many times more effective than MAS based on within-family linkage mapping. In this proposal we developed a protocol leading from family based QTL mapping to population-wide LD between markers and the QTL Major conclusions, solutions, achievements. The critical importance of marker informativity for application of the SRG design in outcrossing random mating populations was identified, and an alternative Fractioned Pool Design (FPD) based on selective DNA pooling was developed. We demonstrated the feasibility of constructing a BAC contig across a targeted chromosomal region flanking the marker RM188 on bovine chromosome BTA4, which was shown in previous work to contain a QTL affecting milk production traits. BAC end sequences were obtained and successfully screened for SNPs. LD studies of these SNPs in the Israel population, and of an independent set of SNPs taken across the entire proximal region of BTA4 in the USA population, showed a much lower degree of LD than previously reported in the literature. Only at distances in the sub-cM level did an appreciable fraction of SNP marker-pairs show levels of LD useful for MAS. In contrast, studies in the Israel population using microsatellite markers, presented an equivalent degree of LD at a 1-5 separation distance. SNP LD appeared to reflect historical population size of Bostaurus (Ne=5000- 10,000), while microsatellite LD appeared to be in proportion to more recent effective population size of the Holstein breed (Ne=50-100). An appreciable fraction of the observed LD was due to Family admixture structure of the Holstein population. The SNPs MEOX2/IF2G (found within the gene SETMAR at 23,000 bp from RM188) and SNP23 were significantly associated with PTA protein, Cheese dollars and Net Merit Protein in the Davis bull resource population, and were also associated with protein and casein percentages in the Davis cow resource population. Implications. These studies document a major difference in degree of LD presented by SNPs as compared to microsatellites, and raise questions as to the source of this difference and its implications for QTL mapping and MAS. The study lends significant support to the targeted approach to fine map a previously identified QTL. Using high density genotyping with SNP discovered in flanking genes to the QTL, we have identified important markers associated with milk protein percentage that can be tested in markers assisted selection programs.