Academic literature on the topic 'Invasion time'
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Journal articles on the topic "Invasion time"
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Stigall, Alycia L. "The Invasion Hierarchy: Ecological and Evolutionary Consequences of Invasions in the Fossil Record." Annual Review of Ecology, Evolution, and Systematics 50, no. 1 (November 2, 2019): 355–80. http://dx.doi.org/10.1146/annurev-ecolsys-110617-062638.
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Species invasions are pervasive in Earth history, yet the ecological and evolutionary consequences vary greatly. Ancient invasion events can be organized in a hierarchy of increasing invasion intensity from ephemeral invasions to globally pervasive invasive regimes. Each level exhibits emergent properties exceeding the sum of interactions at lower levels. Hierarchy levels correspond to, but do not always exactly correlate with, geographic extent of invasion success. The ecological impacts of lower-level impacts can be negligible or result in temporary community accommodation. Invasion events at moderate to high levels of the hierarchy permanently alter ecological communities, regional faunas, and global ecosystems. The prevalence of invasive species results in evolutionary changes by fostering niche evolution, differential survival of ecologically generalized taxa, faunal homogenization, and suppressing speciation. These impacts can contribute to mass extinctions and biodiversity crises that alter the trajectory of ecological and evolutionary patterns of life. The fossil record provides a long-term record of how invasion impacts may scale up through time, which can augment ecological studies of modern species invasions.
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Richardson, David M., and Petr Pyšek. "Plant invasions: merging the concepts of species invasiveness and community invasibility." Progress in Physical Geography: Earth and Environment 30, no. 3 (July 2006): 409–31. http://dx.doi.org/10.1191/0309133306pp490pr.
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This paper considers key issues in plant invasion ecology, where findings published since 1990 have significantly improved our understanding of many aspects of invasions. The review focuses on vascular plants invading natural and semi-natural ecosystems, and on fundamental ecological issues relating to species invasiveness and community invasibility. Three big questions addressed by the SCOPE programme in the 1980s (which species invade; which habitats are invaded; and how can we manage invasions?) still underpin most work in invasion ecology. Some organizing and unifying themes in the field are organism-focused and relate to species invasiveness (the tens rule; the concept of residence time; taxonomic patterns and Darwin’s naturalization hypothesis; issues of phenotypic plasticity and rapid evolutionary change, including evolution of increased competitive ability hypothesis; the role of long-distance dispersal). Others are ecosystem-centred and deal with determinants of the invasibility of communities, habitats and regions (levels of invasion, invasibility and propagule pressure; the biotic resistance hypothesis and the links between diversity and invasibility; synergisms, mutualisms, and invasional meltdown). Some theories have taken an overarching approach to plant invasions by integrating the concepts of species invasiveness and community invasibility (a theory of seed plant invasiveness; fluctuating resources theory of invasibility). Concepts, hypotheses and theories reviewed here can be linked to the naturalization-invasion continuum concept, which relates invasion processes with a sequence of environmental and biotic barriers that an introduced species must negotiate to become casual, naturalized and invasive. New research tools and improved research links between invasion ecology and succession ecology, community ecology, conservation biology and weed science, respectively, have strengthened the conceptual pillars of invasion ecology.
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Cerwenka, Alexander F., Joerg Brandner, Dimitriy Dashinov, and Juergen Geist. "Small but Mighty: The Round Goby (Neogobius melanostomus) as a Model Species of Biological Invasions." Diversity 15, no. 4 (April 6, 2023): 528. http://dx.doi.org/10.3390/d15040528.
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Invasive “game-changer” species cause severe ecological impacts such as “phase shifts” in recipient ecosystems all over the world. Since the early 1990s, the ongoing global spread of the small but highly invasive Ponto-Caspian round goby Neogobius melanostomus into diverse freshwater and marine ecosystems has been observed. We postulate that this species is an ideal model to better understand and mitigate aquatic invasions. Its wide invaded range, as well as its diverse impacts on native species, have triggered a large body of research worldwide concerning its spread, ecology, and traits facilitating invasion. Several hypotheses related to invasiveness have been tested for the round goby, which are also applicable to other invasive species and for understanding general principles in invasion biology. However, a common theory explaining invasion success, especially in round goby, is still lacking. Many case studies do not consider time since invasion and use different sampling protocols and methodologies, hampering the comparability of results and conclusions. We thus propose strengthening the network of goby researchers and establishing long-term databases based on continuous and harmonized monitoring covering all stages of the invasion process as crucial requirements to better understand and manage aquatic invasions. In many cases, such monitoring can easily be integrated into existing survey schemes.
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Goldstein, Joshua, Jaewoo Park, Murali Haran, Andrew Liebhold, and Ottar N. Bjørnstad. "Quantifying spatio-temporal variation of invasion spread." Proceedings of the Royal Society B: Biological Sciences 286, no. 1894 (January 9, 2019): 20182294. http://dx.doi.org/10.1098/rspb.2018.2294.
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— The spread of invasive species can have far-reaching environmental and ecological consequences. Understanding invasion spread patterns and the underlying process driving invasions are key to predicting and managing invasions. — We combine a set of statistical methods in a novel way to characterize local spread properties and demonstrate their application using simulated and historical data on invasive insects. Our method uses a Gaussian process fit to the surface of waiting times to invasion in order to characterize the vector field of spread. — Using this method, we estimate with statistical uncertainties the speed and direction of spread at each location. Simulations from a stratified diffusion model verify the accuracy of our method. — We show how we may link local rates of spread to environmental covariates for two case studies: the spread of the gypsy moth ( Lymantria dispar ), and hemlock woolly adelgid ( Adelges tsugae ) in North America. We provide an R-package that automates the calculations for any spatially referenced waiting time data.
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Sheppard, Christine S., and Marco R. Brendel. "Competitive ability of native and alien plants: effects of residence time and invasion status." NeoBiota 65 (May 25, 2021): 47–69. http://dx.doi.org/10.3897/neobiota.65.63179.
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Competition is commonly thought to underlie the impact of plant invasions. However, competitive effects of aliens and competitive response of natives may also change over time. Indeed, as with time, the novelty of an invader decreases, the accumulated eco-evolutionary experience of resident species may eventually limit invasion success. We aimed to gain insights on whether directional changes in biotic interactions over time or more general differences between natives and aliens, for instance, resulting from an introduction bias, are relevant in determining competitive ability. We conducted a pairwise competition experiment in a target-neighbour design, using 47 Asteraceae species with residence times between 8 years-12,000 years in Germany. We first tested whether there are differences in performance in intraspecific competition amongst invasion status groups, that is casual and established neophytes, archaeophytes or native species. We then evaluated whether competitive response and effects depend on residence time or invasion status. Lastly, we assessed whether competitive effects influence range sizes. We found only limited evidence that native target species tolerate neighbours with longer potential co-existence times better, whereas differences in competitive ability were mostly better explained by invasion status than residence time. Although casual neophytes produced most biomass in intraspecific competition, they had the weakest per-capita competitive effects on natives. Notably, we did not find differences between established neophytes and natives, both of which ranked highest in interspecific competitive ability. This lack of differences might be explained by a biased selection of highly invasive or rare native species in previous studies or because invasion success may result from mechanisms other than interspecific competitive superiority. Accordingly, interspecific per-capita competitive effects did not influence range sizes. Further studies across a broader range of environmental conditions, involving other biotic interactions that indirectly influence plant-plant interactions, may clarify when eco-evolutionary adaptations to new invaders are a relevant mechanism.
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JOHNSTONE, I. M. "PLANT INVASION WINDOWS: A TIME-BASED CLASSIFICATION OF INVASION POTENTIAL." Biological Reviews 61, no. 4 (November 1986): 369–94. http://dx.doi.org/10.1111/j.1469-185x.1986.tb00659.x.
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Villarreal, Miguel, Christopher Soulard, and Eric Waller. "Landsat Time Series Assessment of Invasive Annual Grasses Following Energy Development." Remote Sensing 11, no. 21 (October 30, 2019): 2553. http://dx.doi.org/10.3390/rs11212553.
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Invasive annual grasses are of concern in much of the western United States because they tolerate resource variability and have high reproductive capacity, with propagules that are readily dispersed in disturbed areas like those created and maintained for energy development. Early season invasive grasses “green up” earlier than most native plants, producing a distinct pulse of greenness in the early spring that can be exploited to identify their location using multi-date imagery. To determine if invasive annual grasses increased around energy developments after the construction phase, we calculated an invasives index using Landsat TM and ETM+ imagery for a 34-year time period (1985–2018) and assessed trends for 1755 wind turbines installed between 1988 and 2013 in the southern California desert. The index uses the maximum Normalized Difference Vegetation Index (NDVI) for early season greenness (January-June), and mean NDVI (July–October) for the later dry season. We estimated the relative cover of invasive annuals each year at turbine locations and control sites and tested for changes before and after each turbine was installed. The time series was also mapped across the region and temporal trends were assessed relative to seasonal precipitation. The results showed an increase in early season invasives at turbine sites after installation, but also an increase in many of the surrounding control areas. Maps of the invasive index show a region-wide increase starting around 1998, and much of the increase occurred in areas surrounding wind development sites. These results suggest that invasions around the energy developments occurred within the context of a larger regional invasion, and while the development did not necessarily initiate the invasion, annual grasses were more prevalent around the developments.
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Dutta, Dipanwita, Gang Chen, Chen Chen, Sara A. Gagné, Changlin Li, Christa Rogers, and Christopher Matthews. "Detecting Plant Invasion in Urban Parks with Aerial Image Time Series and Residual Neural Network." Remote Sensing 12, no. 21 (October 24, 2020): 3493. http://dx.doi.org/10.3390/rs12213493.
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Invasive plants are a major agent threatening biodiversity conservation and directly affecting our living environment. This study aims to evaluate the potential of deep learning, one of the fastest-growing trends in machine learning, to detect plant invasion in urban parks using high-resolution (0.1 m) aerial image time series. Capitalizing on a state-of-the-art, popular architecture residual neural network (ResNet), we examined key challenges applying deep learning to detect plant invasion: relatively limited training sample size (invasion often confirmed in the field) and high forest contextual variation in space (from one invaded park to another) and over time (caused by varying stages of invasion and the difference in illumination condition). To do so, our evaluations focused on a widespread exotic plant, autumn olive (Elaeagnus umbellate), that has invaded 20 urban parks across Mecklenburg County (1410 km2) in North Carolina, USA. The results demonstrate a promising spatial and temporal generalization capacity of deep learning to detect urban invasive plants. In particular, the performance of ResNet was consistently over 96.2% using training samples from 8 (out of 20) or more parks. The model trained by samples from only four parks still achieved an accuracy of 77.4%. ResNet was further found tolerant of high contextual variation caused by autumn olive’s progressive invasion and the difference in illumination condition over the years. Our findings shed light on prioritized mitigation actions for effectively managing urban invasive plants.
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Gruntman, Michal, and Udi Segev. "Effect of residence time on trait evolution in invasive plants: review and meta-analysis." NeoBiota 91 (February 22, 2024): 99–124. http://dx.doi.org/10.3897/neobiota.91.109251.
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The success of invasive species is often attributed to rapid post-introduction evolution, due to novel selection pressures at the introduced range. However, evolutionary shifts in invasion-promoting traits can also take place within the introduced range over time. Here, we first present a review of the proposed hypotheses regarding the selection pressures and trait divergence along gradients of invasion history and the studies that examined them. In addition, we present the results of a meta-analysis aimed to provide a more general overview of current knowledge on trait evolution with time since introduction. Invasion-promoting traits, including growth, competitive ability and dispersal ability, were proposed to decline in more established populations with a long invasion history due to the attenuation of selection pressures, such as enemy release or interspecific competition, while herbivore defence was suggested to increase. Our meta-analysis results reveal a general indication for the evolution of invasive plants with residence time for most of the studied traits. However, this divergence did not have a consistent direction in most traits, except for growth, which, in contrast with our prediction, increased with residence time. The lack of empirical support for the predicted change in most of the studied traits over time suggests trait evolution might be affected by other context-dependent factors such as climatic gradients along invasion routes. Similarly, the increased allocation to size in older and more established populations may be driven by increased conspecific competition pressure experienced in these populations. The general temporal effect found in our meta-analysis stresses the need to consider population age when comparing attributes of invasive plants between native and invasive ranges. Moreover, the increased size of invasive plants in older populations, suggests that the dominance of these plants might not attenuate with time since introduction, thus highlighting the need to further explore the long-term dynamics between invasive plants and their recipient native communities.
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Romanuk, Tamara N., Yun Zhou, Ulrich Brose, Eric L. Berlow, Richard J. Williams, and Neo D. Martinez. "Predicting invasion success in complex ecological networks." Philosophical Transactions of the Royal Society B: Biological Sciences 364, no. 1524 (June 27, 2009): 1743–54. http://dx.doi.org/10.1098/rstb.2008.0286.
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A central and perhaps insurmountable challenge of invasion ecology is to predict which combinations of species and habitats most effectively promote and prevent biological invasions. Here, we integrate models of network structure and nonlinear population dynamics to search for potential generalities among trophic factors that may drive invasion success and failure. We simulate invasions where 100 different species attempt to invade 150 different food webs with 15–26 species and a wide range (0.06–0.32) of connectance. These simulations yield 11 438 invasion attempts by non-basal species, 47 per cent of which are successful. At the time of introduction, whether or not the invader is a generalist best predicts final invasion success; however, once the invader establishes itself, it is best distinguished from unsuccessful invaders by occupying a lower trophic position and being relatively invulnerable to predation. In general, variables that reflect the interaction between an invading species and its new community, such as generality and trophic position, best predict invasion success; however, for some trophic categories of invaders, fundamental species traits, such as having the centre of the feeding range low on the theoretical niche axis (for non-omnivorous and omnivorous herbivores), or the topology of the food web (for tertiary carnivores), best predict invasion success. Across all invasion scenarios, a discriminant analysis model predicted successful and failed invasions with 76.5 per cent accuracy for properties at the time of introduction or 100 per cent accuracy for properties at the time of establishment. More generally, our results suggest that tackling the challenge of predicting the properties of species and habitats that promote or inhibit invasions from food web perspective may aid ecologists in identifying rules that govern invasions in natural ecosystems.
Dissertations / Theses on the topic "Invasion time"
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Gatehouse, Hazel A. W. "Ecology of the naturalisation and geographic distribution of the non-indigenous seed plant species of New Zealand." Diss., Lincoln University, 2008. http://hdl.handle.net/10182/1009.
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The naturalisation and subsequent spread of non-indigenous plant species (NIPS) is a major problem for most regions of the world. Managing plant invasions requires greater understanding of factors that determine initial naturalisation and distribution of wild NIPS. By the year 2000, 2252 NIPS were recorded as wild (1773 fully naturalised and 479 casual) in New Zealand. From published literature and electronic herbaria records, I recorded year of discovery of wild populations, and regional distribution of these wild NIPS. I also recorded species related attributes hypothesised to affect naturalisation and/or distribution, including global trade, human activities, native range and biological data; and regional attributes hypothesised to affect distribution, including human population densities, land use/cover, and environmental data. I used interval-censored time-to-event analyses to estimate year of naturalisation from discovery records, then analysed the importance of historical, human activity, biogeographical and biological attributes in determining patterns of naturalisation. Typically, NIPS that naturalised earlier were herbaceous, utilitarian species that were also accidentally introduced and/or distributed, with a wide native range that included Eurasia, naturalised elsewhere, with a native congener in New Zealand. In the year 2000, 28% of wild NIPS occupied only one region, 18% occupied two regions, decreasing incrementally to 2.5 % for nine regions, but with 13.5% occupying all ten regions. I used generalised linear models (GLMs) with binomial distribution to determine predictors of whether a wild NIPS occupied ten regions or not, and GLMs with Poisson distribution for wild NIPS occupying 0 – 9 regions. As expected, the dominant effect was that species discovered earlier occupied more regions. Utilitarian wild NIPS that were also accidentally introduced and/or distributed, and wild NIPS with a native congener tended to be more widely distributed, but results for other attributes varied between datasets. Although numbers of wild NIPS recorded in regions of New Zealand were sometimes similar, composition of wild NIPS was often very different. I used nonmetric multidimensional scaling (NMDS) to determine dissimilarity in composition between regions. Then, after reducing correlation between predictor variables using principal components analyses (PCAs), I tested the importance of regional variables in determining the regional composition of wild NIPS using metaMDS. The density of human populations best explained the dissimilarity in composition, but temperature gradients and water availability gradients were also important. In the year 2000 more than 1100 (60%) of the 1773 fully naturalised NIPS in mainland New Zealand had each been recorded in Northland/Auckland and Canterbury, and at the other end of the scale, Southland and Westland each had fewer than 500 (30%). I used GLMs to analyse the importance of people and environment in determining the numbers of wild NIPS in each region. Because I conducted multiple tests on the same dataset I used sequential Bonferroni procedures to adjust the critical P-value. Only human population density was important in explaining the numbers of NIPS in the regions. Overall, humans were the dominant drivers in determining the patterns of naturalisation and spread, although environment helps determine the composition of NIPS in regions. Incorporating human associated factors into studies of wild NIPS helps improve the understanding of the stages in the naturalisation and spread process.
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Jethani, Kajal. "The development of a real-time diagnostic RT-PCR based on the molecular analysis of Aspergillus fumigatus genes regulated during the early stages of lung invasion." Thesis, King's College London (University of London), 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.441363.
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Brame, Hannah-Maria R. "Are Cincinnatian (Late Ordovician) Niche Stability Responses to Variable Environmental Changes Congruent Across Clades, Taxonomic Scales, and Through Time?" Ohio University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1366634147.
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Brouard, Vianney. "Cell dynamics of multitype populations in oncology and Invasion probability of cooperative parasites in structured host populations." Electronic Thesis or Diss., Lyon, École normale supérieure, 2024. http://www.theses.fr/2024ENSL0037.
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Cette thèse porte sur l'étude de deux modèles stochastiques liés à des problèmes médicaux. Le premier vise à comprendre le processus épidémique généré par des bactériophages coopératifs dans une population de bactéries résistantes aux antibiotiques. Pour cela, nous introduisons un modèle épidémiologique où les infections sont générées par la coopération de parasites dans une population d'hôtes structurée selon un modèle de configuration. Une transition de phase est observée pour la probabilité d'invasion dépendant du degré de connectivité des sommets et du nombre de parasites générés lors d'une infection d'un hôte. Au seuil critique, la probabilité d'invasion est identifiée comme la probabilité de survie d'un processus de Galton-Watson.Dans le but d'obtenir un modèle biologiquement plus pertinent, nous avons analysé un modèle similaire où une structure spatiale est ajoutée à la population d'hôtes en utilisant un "random geometric graph". Nous avons montré qu'une telle structure spatiale facilite la coopération des parasites. Une transition de phase similaire se produit où au seuil critique, des bornes supérieure et inférieure sont obtenues pour la probabilité d'invasion en tant que probabilités de survie de deux processus de branchement avec coopération.La deuxième question médicale concerne la compréhension de l'évolution de la composition génétique d'une tumeur en formation, en utilisant des processus de naissance et de mort multitypes branchants sur un espace de traits fini. Considérant une évolution neutre et délétère, nous fournissons des résultats au premier ordre asymptotique pour toutes les tailles des sous-populations mutantes. En particulier, nous capturons la stochasticité associée aux tailles des sous-populations mutantes lorsqu'une tumeur est observée cliniquement, et surtout nous caractérisons les chemins évolutifs effectifs, fournissant des informations sur le passé, le présent et le futur de l'évolution tumorale.Au-delà de ce cadre restrictif d'évolution neutre et délétère, nous proposons une nouvelle méthode pour comprendre le premier ordre asymptotique du premier trait mutant sélectifThis thesis focuses on the study of two stochastic models related to medical problems. The first one lies on understanding infection spread of cooperating bacteriophages on a structured multi-drug resistant bacterial host population. Motivated by this example, we introduce an epidemiological model where infections are generated by cooperation of parasites in a host population structured on a configuration model. We analysed the invasion probability for which we obtain a phase transition depending on the connectivity degree of the vertices and the offspring number of parasites during an infection of a host. At the critical scaling, the invasion probability is identified as the survival probability of a Galton-Watson process. With the aim to get a biological more relevant model, we analysed a similar model where a spatial structure is added for the host population using a random geometric graph. We have shown that such spatial structure facilitates cooperation of parasites. A similar phase transition occurs where at the same critical scaling the invasion probability is upper and lower bounded by the survival probabilities of two discrete branching processes with cooperation. The second medical question deals with understanding the evolution of the genetic composition of a tumor under carcinogenesis, using multitype birth and death branching process models on a general finite trait space. In the case of neutral and deleterious cancer evolution, we provide first-order asymptotics results on all mutant subpopulation sizes. In particular such results capture the randomness of all cell trait sizes when a tumor is clinically observed, and mostly it allows to characterize the effective evolutionary pathways, providing information on the past, present, and future of tumor evolution.Moving beyond this restrictive neutral and deleterious cancer evolution framework, we provide a new method to understand the first selective mutant trait size
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Walpole, Carina Maree. "The function and mechanisms of action of ghrelin and obestatin in ovarian cancer." Thesis, Queensland University of Technology, 2012. https://eprints.qut.edu.au/63497/1/Carina_Walpole_Thesis.pdf.
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In this study, we have demonstrated that the preproghrelin derived hormones, ghrelin and obestatin, may play a role in ovarian cancer. Ghrelin and obestatin stimulated an increase in cell migration in ovarian cancer cell lines and may play a role in cancer progression. Ovarian cancer is the leading cause of death among gynaecological cancers and is the sixth most common cause of cancer-related deaths in women in developed countries. As ovarian cancer is difficult to diagnose at a low tumour grade, two thirds of ovarian cancers are not diagnosed until the late stages of cancer development resulting in a poor prognosis for the patient. As a result, current treatment methods are limited and not ideal. There is an urgent need for improved diagnostic markers, as well better therapeutic approaches and adjunctive therapies for this disease.
Ghrelin has a number of important physiological effects, including roles in appetite regulation and the stimulation of growth hormone release. It is also involved in regulating the immune, cardiovascular and reproductive systems and regulates sleep, memory and anxiety, and energy metabolism. Over the last decade, the ghrelin axis, (which includes the hormones ghrelin and obestatin and their receptors), has been implicated in the pathogenesis of many human diseases and it may t may also play an important role in the development of cancer. Ghrelin is a 28 amino acid peptide hormone that exists in two forms. Acyl ghrelin (usually referred to as ghrelin), has a unique n-octanoic acid post-translational modification (which is catalysed by ghrelin O-acyltransferase, GOAT), and desacyl ghrelin, which is a non-octanoylated form. Octanoylated ghrelin acts through the growth hormone secretagogue receptor type 1a (GHSR1a). GHSR1b, an alternatively spliced isoform of GHSR, is C-terminally truncated and does not bind ghrelin. Ghrelin has been implicated in the pathophysiology of a number of diseases Obestatin is a 23 amino acid, C-terminally amidated peptide which is derived from preproghrelin. Although GPR39 was originally thought to be the obestatin receptor this has been disproven, and its receptor remains unknown. Obestatin may have as diverse range of roles as ghrelin. Obestatin improves memory, inhibits thirst and anxiety, increases pancreatic juice secretion and has cardioprotective effects. Obestatin also has been shown to regulate cell proliferation, differentiation and apoptosis in some cell types.
Prior to this study, little was known regarding the functions and mechanisms of action ghrelin and obestatin in ovarian cancer. In this study it was demonstrated that the full length ghrelin, GHSR1b and GOAT mRNA transcripts were expressed in all of the ovarian-derived cell lines examined (SKOV3, OV-MZ-6 and hOSE 17.1), however, these cell lines did not express GHSR1a. Ovarian cancer tissue of varying stages and normal ovarian tissue expressed the coding region for ghrelin, obestatin, and GOAT, but not GHSR1a, or GHSR1b. No correlations between cancer grade and the level of expression of these transcripts were observed.
This study demonstrated for the first time that both ghrelin and obestatin increase cell migration in ovarian cancer cell lines. Treatment with ghrelin (for 72 hours) significantly increased cell migration in the SKOV3 and OV-MZ-6 ovarian cancer cell lines. Ghrelin (100 nM) stimulated cell migration in the SKOV3 (2.64 +/- 1.08 fold, p <0.05) and OV-MZ-6 (1.65 +/- 0.31 fold, p <0.05) ovarian cancer cell lines, but not in the representative normal cell line hOSE 17.1. This increase in migration was not accompanied by an increase in cell invasion through Matrigel. In contrast to other cancer types, ghrelin had no effect on proliferation. Ghrelin treatment (10nM) significantly decreased attachment of the SKOV3 ovarian cancer cell line to collagen IV (24.7 +/- 10.0 %, p <0.05), however, there were no changes in attachment to the other extracellular matrix molecules (ECM) tested (fibronectin, vitronectin and collagen I), and there were no changes in attachment to any of the ECM molecules in the OV-MZ-6 or hOSE 17.1 cell lines. It is, therefore, unclear if ghrelin plays a role in cell attachment in ovarian cancer.
As ghrelin has previously been demonstrated to signal through the ERK1/2 pathway in cancer, we investigated ERK1/2 signalling in ovarian cancer cell lines. In the SKOV3 ovarian cancer cell line, a reduction in ERK1/2 phosphorylation (0.58 fold +/- 0.23, p <0.05) in response to 100 nM ghrelin treatment was observed, while no significant change in ERK1/2 signalling was seen in the OV-MZ-6 cell line with treatment. This suggests that this pathway is unlikely to be involved in mediating the increased migration seen in the ovarian cancer cell lines with ghrelin treatment.
In this study ovarian cancer tissue of varying stages and normal ovarian tissue expressed the coding region for obestatin, however, no correlation between cancer grade and level of obestatin transcript expression was observed. In the ovarian-derived cell lines studied (SKOV3, OV-MZ-6 and hOSE 17.1) it was demonstrated that the full length preproghrelin mRNA transcripts were expressed in all cell lines, suggesting they have the ability to produce mature obestatin.
This is the first study to demonstrate that obestatin stimulates cell migration and cell invasion. Obestatin induced a significant increase in migration in the SKOV3 ovarian cancer cell line with 10 nM (2.80 +/- 0.52 fold, p <0.05) and 100 nM treatments (3.12 +/- 0.68 fold, p <0.05) and in the OV-MZ-6 cancer cell line with 10 nM (2.04 +/- 0.10 fold, p <0.01) and 100 nM treatments (2.00 +/- 0.37 fold, p <0.05). Obestatin treatment did no affect cell migration in the hOSE 17.1normal ovarian epithelial cell line. Obestatin treatment (100 nM) also stimulated a significant increase in cell invasion in the OV-MZ-6 ovarian cancer cell line (1.45 fold +/- 0.13, p <0.05) and in the hOSE17.1 normal ovarian cell line cells (1.40 fold +/- 0.04 and 1.55 fold +/- 0.05 respectively, p <0.01) with 10 nM and 100 nM treatments. Obestatin treatment did not stimulate cell invasion in the SKOV3 ovarian cancer cell line. This lack of obestatin-stimulated invasion in the SKOV3 cell line may be a cell line specific result.
In this study, obestatin did not stimulate cell proliferation in the ovarian cell lines and it has previously been shown to have no effect on cell proliferation in the BON-1 pancreatic neuroendocrine and GC rat somatotroph tumour cell lines. In contrast, obestatin has been shown to affect cell proliferation in gastric and thyroid cancer cell lines, and in some normal cell lines. Obestatin also had no effect on attachment of any of the cell lines to any of the ECM components tested (fibronectin, vitronectin, collagen I and collagen IV).
The mechanism of action of obestatin was investigated further using a two dimensional-difference in gel electrophoresis (2D-DIGE) proteomic approach. After treatment with obestating (0, 10 and 100 nM), SKOV3 ovarian cancer and hOSE 17.1 normal ovarian cell lines were collected and 2D-DIGE analysis and mass spectrometry were performed to identify proteins that were differentially expressed in response to treatment. Twenty-six differentially expressed proteins were identified and analysed using Ingenuity Pathway Analysis (IPA). This linked 16 of these proteins in a network. The analysis suggested that the ERK1/2 MAPK pathway was a major mediator of obestatin action. ERK1/2 has previously been shown to be associated with obestatin-stimulated cell proliferation and with the anti-apoptotic effects of obestatin.
Activation of the ERK1/2 signalling pathway by obestatin was, therefore, investigated in the SKOV3 and OV-MZ-6 ovarian cancer cell lines using anti-active antibodies and Western immunoblots. Obestatin treatment significantly decreased ERK1/2 phosphorylation at higher obestatin concentrations in both the SKOV3 (100 nM and 1000 nM) and OV-MZ-6 (1000 nM) cell lines compared to the untreated controls. Currently, very little is known about obestatin signalling in cancer.
This thesis has demonstrated for the first time that the ghrelin axis may play a role in ovarian cancer migration. Ghrelin and obestatin increased cell migration in ovarian cancer cell lines, indicating that they may be a useful target for therapies that reduce ovarian cancer progression. Further studies investigating the role of the ghrelin axis using in vivo ovarian cancer metastasis models are warranted.
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Royer, Lucas. "Real-time tracking of deformable targets in 3D ultrasound sequences." Thesis, Rennes, INSA, 2016. http://www.theses.fr/2016ISAR0017/document.
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De nos jours, les traitements mini-invasifs, tels que l'ablation par radiofréquence, sont de plus en plus utilisés car ils permettent d'éliminer localement les tumeurs à partir de l'insertion d'une aiguille. Cependant, le succès de ces procédures dépend de la précision du positionnement de l'aiguille par rapport aux structures anatomiques. Afin de garantir un placement correct, l'imagerie échographique est souvent utilisée car elle a l'avantage d'être temps-réelle, bas coût, et non-invasive. En revanche, celle modalité peut compliquer la visualisation de certaines structures en raison de sa qualité et de son champ de vue limité. En outre, la précision des interventions peut aussi être perturbée par les déplacements de tissus liés aux mouvements physiologiques du patient et à la manipulation d'instruments médicaux. Afin d'aider le chirurgien à mieux cibler certaines structures anatomiques, de nombreuses équipes de recherche ont proposé des travaux permettant d'estimer la position de régions d'intérêts dans l'imagerie échographique. Cette thèse propose plusieurs contributions permettant de suivre en temps réel des structures déformables dans des séquences d'échographie 3D. Une première contribution repose sur l'utilisation conjointe de l'information visuelle dense et d'une méthode de simulation physique. Dans cette thèse, nous avons aussi proposé un nouveau critère de similarité spécifique à l'imagerie échographique basé sur une étape de détection d'ombres. Enfin, la dernière contribution est liée à une stratégie de suivi hybride permettant d'améliorer la qualité des images. A partir de ces contributions, nous proposons une méthode de suivi robuste au bruit de type« speckle », aux ombres et aux changements d'intensité perturbant l'imagerie échographique. Les performances des différentes contributions sont évaluées à partir de données simulées et de données acquises sur maquettes et sur volontaires humains. Ces résultats montrent que notre méthode est robuste à différents artefacts de l'imagerie échographique. En outre, nous démontrons la performance de notre approche par rapport à différentes méthodes de l'état de l'art sur des bases de données publiques fournies par les challenges MICCAI CLUST'14 et CLUST'15. Dans cette thèse, nous proposons également une application permettant de combiner l'imagerie échographique à l'imagerie par résonance magnétique (IRM). Cette méthode permet d'observer des structures anatomiques non-visibles dans l'imagerie échographique durant l'intervention. Elle est basée sur la combinaison d'une méthode de suivi et d'un recalage multi-modal obtenu à partir d'un système de localisation externe. Cette application a été évaluée sur un volontaire sain à partir d'une plateforme liée au centre Hospitalier Universitaire de RennesNowadays, mini-invasive treatments, such as radio-frequency ablation, are increasingly being used because they allow eliminating tumors locally from needle insertion. However, the success of these therapies depends on the accurate positioning of the needle with respect to anatomical structures. To ensure correct placement, ultrasound (US) imaging is often used since this system has the advantage to be real-time, low-cost, and non-invasive. However, during the intervention, US imaging can complicate the visualization of targeted structures due to its poor quality and its limited field of view. Furthermore, the accuracy of these interventions may also be perturbed by both physiological movements and medical tools displacements that introduce motions of anatomical structures. To help the surgeon to better target malignant tissues, many research teams have proposed different method in order to estimate the position of regions of interest in ultrasound imaging. This thesis provides several contributions that allow tracking deformable structures in 3D ultrasound sequences. We first present a method that allows providing robust estimation of target positions by combining an intensity-based approach and mechanical model simulation. In this thesis, we also propose novel ultrasound-specific similarity criterion based on prior step that aims at detecting shadows. The last contribution is related to a hybrid tracking strategy that allows improving quality of ultrasound images. From these contributions, we propose a tracking method that has the advantage to be invariant to speckle noise, shadowing and intensity changes that can occur in US imaging. The performance and limitations of the proposed contributions are evaluated through simulated data, phantom data, and real-data obtained from different volunteers. Simulation and phantom results show that our method is robust to several artefacts of US imaging such as shadows and speckle decorrelation. Furthermore, we demonstrate that our approach outperforms state-of-the-art methods on the 3D public databases provided by MICCAI CLUST'14 and CLUST'15 challenges. In this thesis, we also propose an application that combines ultrasound imaging to Magnetic Resonance lmaging (MRI). This method allows observing anatomical structures that are not visible in US imaging during the intervention. It is based on the combination between US tracking method and multi modal registration obtained from external localization system. This application was evaluated on a volunteer thanks to an MRJ imaging platform locate at the University Hospital of Rennes
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Jankovic, Masha. "Modelling biological invasions : population cycles, waves and time delays." Thesis, University of Leicester, 2015. http://hdl.handle.net/2381/31392.
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Biological invasions are rapidly gaining importance due to the ever-increasing number of introduced species. Alongside the plenitude of empirical data on invasive species there exists an equally broad range of mathematical models that might be of use in understanding biological invasions. This thesis aims to address several issues related to modelling invasive species and provide insight into their dynamics. Part I (Chapter 2) documents a case study of the gypsy moth, Lymantria dispar, invasion in the US. We propose an alternative hypothesis to explain the patchiness of gypsy moth spread entailing the interplay between dispersal, predation or a viral infection and the Allee effect. Using a reaction-diffusion framework we test the two models (prey-predator and susceptible-infected) and predict qualitatively similar patterns as are observed in natural populations. As high density gypsy moth populations cause the most damage, estimating the spread rate would be of help in any suppression strategy. Correspondingly, using a diffusive SI model we are able to obtain estimates of the rate of spread comparable to historical data. Part II (Chapters 3, 4 and 5) is more methodological in nature, and in a single species context we examine the effect of an ubiquitous phenomenon influencing population dynamics time delay. In Chapter 3 we show that contrary to the general opinion, time delays are not always destabilising, using a delay differential equation with discrete time delay. The concept of distributed delay is introduced in Chapter 4 and studied through an integrodifferential model. Both Chapters 3 and 4 focus on temporal dynamics of populations, so we further this consideration to include spatial effects in Chapter 5. Using two different representations of movement, we show that the onset of spatiotemporal chaos in the wake of population fronts is possible in a single species model.
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Valerio, Fernando Passador. "Influência da doxiciclina em endometriose experimentalmente induzida em ratas." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/17/17145/tde-19072018-115724/.
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A endometriose é uma doença de origem multifatorial, caracterizada por presença de tecido endometrial fora da cavidade uterina, responsável por sintomas álgicos com grande impacto na qualidade de vida da paciente, além de ser um dos principais fatores de infertilidade. Muitos estudos já foram realizados no intuito de explicar a etiopatogenia da endometriose, assim como muito tem sido estudado para encontrar novas estratégias de tratamento. Várias linhas de medicamentos têm sido estudadas com este intuito, agindo em diferentes pontos da etiopatogênese da doença, uma delas na inibição de metaloproteinases da matriz extracelular, que tem papel no remodelamento do mesotélio do peritônio e angiogênese. O objetivo deste estudo foi avaliar a influência de uma droga (doxiciclina) de baixo custo, com ação conhecida na inibição das metaloproteinases, em endometriose peritoneal induzida em ratas. Para isso, foram usadas 30 ratas adultas Wistar com lesão induzida de endometriose, divididas em três grupos, um grupo controle (C, n=10) sem tratamento, um grupo onde foi administrado doxiciclina em baixa dose (BD, n=10) e um grupo onde foi realizado doxiciclina em alta dose (AD, n=10). Foi realizada avaliação da área das lesões de cada rata e estudo imunohistoquímico para positividade de anticorpo primário de metaloproteinase de matriz 9 (MMP9) e de inibidor de metaloproteinase de matriz 2 (TIMP2). A doxiciclina atuou reduzindo a área das lesões nos grupos BD e AD (p=0,0052) em relação ao grupo C e reduzindo a expressão do TIMP2 no grupo AD (p=0,0009) em relação aos grupos BD e C. Não houve resultado significativo na expressão da MMP9.Endometriosis is a multifactorial origin disease, characterized by the presence of endometrial tissue outside the uterine cavity, responsible for painful symptoms with important impact on the life quality of the patient, besides being one of the main factors of infertility. Many studies have already been carried out to explain the etiopathogenesis of endometriosis, and much has been studied to find new treatment strategies. Several lines of drugs have been studied for this purpose, acting at different points in the etiopathogenesis of the disease, one of them in the inhibition of extracellular matrix metalloproteinases, which plays a role in the remodeling of the peritoneum mesothelium and angiogenesis. The purpose of this study was to evaluate the influence of a low-cost drug (doxycycline), with known action on the inhibition of metalloproteinases, in induced peritoneal endometriosis in rats. Thirty adult Wistar rats with endometriosis-induced lesions were divided into three groups: one untreated control group (C, n = 10), one group receiving low dose doxycycline (BD, n = 10) and a group where high dose doxycycline (AD, n = 10) was performed. An evaluation of the lesion area of each rat and immunohistochemical study for primary antibody to matrix metalloproteinase 9 (MMP9) and matrix metalloproteinase inhibitor 2 (TIMP2) was performed. Doxycycline worked by reducing the area of lesions in the BD and AD groups (p = 0.0052) in relation to the C group and reducing the expression of TIMP2 in the AD group (p = 0.0009) in relation to the BD and C groups. There was no significant effect on MMP9 expression in the present study.
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Schofield, James. "Real-time acoustic identification of invasive wood-boring beetles." Thesis, University of York, 2011. http://etheses.whiterose.ac.uk/1978/.
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Wood-boring beetles are a cause of significant economic and environmental cost across the world. A number of species which are not currently found in the United Kingdom are constantly at risk of being accidentally imported due to the volume of global trade in trees and timber. The species which are of particular concern are the Asian Longhorn (Anoplophora glabripennis), Citrus Longhorn (A. chinensis) and Emerald Ash Borer (Agrilus planipennis). The Food and Environment Research Agency's plant health inspectors currently manually inspect high risk material at the point of import. The development of methods which will enable them to increase the probability of detection of infestation in imported material are therefore highly sought after. This thesis describes research into improving acoustic larvae detection and species identification methods, and the development of a real-time system incorporating them. The detection algorithm is based upon fractal dimension analysis and has been shown to outperform previously used short-time energy based detection. This is the first time such a detection method has been applied to the analysis of insect sourced sounds. The species identification method combines a time domain feature extraction technique based upon the relational tree representation of discrete waveforms and classification using artificial neural networks. Classification between two species, A. glabripennis and H. bajulus, can be performed with 92% accuracy using Multilayer Perceptron and 96.5% accuracy using Linear Vector Quantisation networks. Classification between three species can be performed with 88.8% accuracy using LVQ. A real-time hand-held PC based system incorporating these methods has been developed and supplied to FERA for further testing. This system uses a combination of dual piezo-electric based USB connected sensors and custom written software which can be used to analyse live recordings of larvae in real-time or use previously recorded data.
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Vasala, K. (Kaija). "Matrix metalloproteinase MMP-2 and MMP-9 and their inhibitors TIMP-1 and TIMP-2 in bladder carcinoma." Doctoral thesis, University of Oulu, 2008. http://urn.fi/urn:isbn:9789514288746.
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Abstract
Bladder cancer when superficial has a good prognosis but it has a high recurrence risk and about 10–15% of the superficial carcinomas will progress into muscle invasive or metastatic type. The most powerful factor for predicting the behavior of bladder carcinoma is the stage of the tumor. Invasion to the lamina propria increases the risk of recurrence and progress to muscle-invasive tumor. Also grade of the tumor and tumor multiplicity associates with high risk for recurrence. New markers are still needed to find those patients who need more and better treatments to avoid the recurrence and progress. The need for new non-invasive markers to diminish the need for frequent cystoscopy in follow-up is also obvious.
Gelatinases MMP-2 and MMP-9 are known to associate to tumor invasion and progression. Also their tissue inhibitors TIMP-1 and TIMP-2 take part in these diversified processes and metastasis formation. In the present work the expression and clinical value of gelatinases MMP-2 and MMP-9 and their tissue inhibitors TIMP-1 and TIMP-2 were evaluated in bladder carcinoma. Primary tissue samples of 121 patients were analyzed for expression of MMP-2 and/or MMP-9 using immunohistochemistry. The serum samples of 87 patients who were treated in the Oncology Department of Oulu University Hospital were collected and studied with ELISA. The control group consisted of 44 healthy volunteers.
Overexperssion of MMP-2 protein correlated significantly to disease-specific survival and showed an independent prognostic value as a biomarker. High MMP-9 expression instead correlated to favorable overall survival of bladder cancer patients. Circulating proMMP-2, TIMP-2 and MMP-2:TIMP-2 complex levels were lower in cancer patients than in healthy volunteers in control group. High levels of all these three markers correlated with better prognosis in bladder cancer patients.
Books on the topic "Invasion time"
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James, Denney. Invasion of the Time Troopers. Nashville, Tenn: Tommy Nelson, 2002.
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Finkelstein, Norman G. "This time we went too far": Truth and consequences of the Gaza invasion. New York, USA: OR Books, 2010.
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Jr, Modesitt L. E. Timediver's dawn. New York: TOR, 1992.
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Metcalfe, Howard Hurtig. Randolph lineages: Being the ancestry of Iris Patricia Followes from the time of the Saxon invasion of England. Decorah, Iowa: Anundsen Pub., 1991.
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Kaphamtengo, Toughlen J. The eastern flank of the Kalonga's state: The case of the Mpinganjira chieftainship to the time of the Yao invasion. [Zomba, Malawi]: University of Malawi, Chancellor College, History Dept., 1990.
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Jones, Mark. Invasion of the rubbernecks: Spinechilling times in Soho. London: Century, 1990.
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Harrison, Lisi. Invasion of the Boy Snatchers. New York: Little, Brown Books for Young Readers, 2008.
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Miles, Barry. The British invasion: [the music, the times, the era]. New York: Sterling, 2009.
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Endrinal, Doninic, Bruce David, and Elliott Swanson, eds. SPACE PATROL CHRONICLES - BOOK TWO: Missions of Daring. New York: Remington-Collier Publishing, 2014.
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Botting, Douglas. Desembarco de Normandía: El raid más grande de la guerra. [Barcelona]: Editorial Optima, 2002.
Find full textBook chapters on the topic "Invasion time"
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Schiesser, W. E. "Metastatic Cancer Cell Invasion of Tissue." In Time Delay ODE/PDE Models, 127–56. Boca Raton : CRC Press, [2020]: CRC Press, 2019. http://dx.doi.org/10.1201/9780367427986-5.
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Petras, James, and Morris Morley. "Washington's Invasion of Panama: Myths and Realities." In Latin America in the Time of Cholera, 79–90. London: Routledge, 2024. http://dx.doi.org/10.4324/9781003567431-7.
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Pyšek, Petr, and Philip E. Hulme. "Biological Invasions in Europe 50 Years after Elton: Time to Sound the ALARM." In Fifty Years of Invasion Ecology, 71–88. Oxford, UK: Wiley-Blackwell, 2010. http://dx.doi.org/10.1002/9781444329988.ch7.
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Carlton, James T. "Deep Invasion Ecology and the Assembly of Communities in Historical Time." In Biological Invasions in Marine Ecosystems, 13–56. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-540-79236-9_2.
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Anton, Oleinik. "Introduction: Post-Truth in Time of War." In A Comparative Analysis of Political and Media Discourses about Russia’s Invasion of Ukraine, 1–28. Cham: Springer Nature Switzerland, 2024. http://dx.doi.org/10.1007/978-3-031-51154-7_1.
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Liu, Jianhua, Zhenhua Liu, and Jianhua Zhang. "Computation of Time-Dependent AIT Responses for Various Reservoirs Using Dynamic Invasion Model." In Recent Advances in Computer Science and Information Engineering, 823–28. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-25789-6_113.
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Sanchez, Lisa, Yuen-Yan Chang, Nora Mellouk, and Jost Enninga. "Time-Resolved Fluorescence Microscopy Screens on Host Protein Subversion During Bacterial Cell Invasion." In Methods in Molecular Biology, 113–31. New York, NY: Springer US, 2022. http://dx.doi.org/10.1007/978-1-0716-2449-4_8.
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Li, Kuncheng, Jingxin Ruan, Jifu Ruan, Yuhang Liu, and Hong Luo. "Application of early identification of water invasion and prediction of water breakthrough time in M gas reservoir." In Advances in Mineral Resources, Geotechnology and Geological Exploration, 450–60. London: CRC Press, 2022. http://dx.doi.org/10.1201/9781003319412-63.
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Rieker, Pernille, and Mathilde T. E. Giske. "EU(ropean) Differentiated Defence Integration." In The European Union in International Affairs, 63–91. Cham: Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-44546-0_4.
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AbstractEven though the need to improve European joint defence capacity has been on the agenda of both NATO and the EU, individually and in partnership for over a decade, it has not yet been fully achieved. The Russian invasion was a brutal reminder that Europe is still largely dependent on the US for its security. This added further momentum to the process of building up a stronger European defence capacity, which has already been ongoing for a decade. The EU’s adoption of the Strategic Compass in March 2022, shortly after the invasion, is crucial in this context. It had been under development for some time (since June 2020) but had to be rewritten due to the invasion. It was intended to represent a great leap forward, as it was to present an action plan towards 2030. Due to recent events, member states were more committed than ever to delivering joint defence capacity, and they sought to do so through greater flexibility, investing more and more efficiently, and cooperating more closely with partners.The geopolitical situation makes Europe more committed and obliged than ever to build a stronger European capacity. Over the past 15 years, a series of different initiatives, at different levels and in different formats, have been launched with this in mind. A recurring question, however, has been whether these many different processes and initiatives result in a more fragmented and complicated European security structure, with unnecessary duplication as a result. Or whether they, through various cooperation agreements and coordination efforts, contribute to a more flexible and stronger European defence structure, where formal structures are less important than commitment to different initiatives. The aim of this chapter is to provide an answer.
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"INVASION." In Time on Target, 70–81. Kentucky Historical Society, 2014. http://dx.doi.org/10.2307/j.ctt130jn2s.9.
Full textConference papers on the topic "Invasion time"
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Aloqalaa, Daniyah A., Jenny A. Hodgson, Dariusz R. Kowalski, and Prudence W. H. Wong. "Estimating Invasion Time in Real Landscapes." In the 2018 2nd International Conference. New York, New York, USA: ACM Press, 2018. http://dx.doi.org/10.1145/3290818.3290825.
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Gupta, Amrita, Mehrdad Farajtabar, Bistra Dilkina, and Hongyuan Zha. "Discrete Interventions in Hawkes Processes with Applications in Invasive Species Management." In 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.2018/470.
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The spread of invasive species to new areas threatens the stability of ecosystems and causes major economic losses. We propose a novel approach to minimize the spread of an invasive species given a limited intervention budget. We first model invasive species spread using Hawkes processes, and then derive closed-form expressions for characterizing the effect of an intervention action on the invasion process. We use this to obtain an optimal intervention plan based on an integer programming formulation, and compare the optimal plan against several ecologically-motivated heuristic strategies used in practice. We present an empirical study of two variants of the invasive control problem: minimizing the final rate of invasions, and minimizing the number of invasions at the end of a given time horizon. The optimized intervention achieves nearly the same level of control that would be attained by completely eradicating the species, but at only 60-80\% of the cost.
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Carvalho, Débora Medeiros de, Josielly Ferreira Bacelar, Joarla Ayres de Morais Estevão, Emanuelle de Lima Barros, Mariana de Souza Arêa Leão, Josie Haydée Lima Ferreira Paranaguá, Carlos Eduardo Moura de Lima, and Sabas Carlos Vieira. "Survival analysis of patients with 10 or more axillary lymph nodes compromised by breast cancer." In Brazilian Breast Cancer Symposium 2023. Mastology, 2023. http://dx.doi.org/10.29289/259453942023v33s1085.
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Objective: The objective of this study was to evaluate survival in patients with 10 or more compromised axillary lymph nodes. Methodology: This is a retrospective cohort study conducted in a private oncology clinic in Teresina, Piauí, Brazil, in the period 1999–2023, where medical records of 12 patients with breast cancer who had 10 or more compromised axillary lymph nodes were analyzed. The following variables were observed: patient age, histological type of tumor, tumor size, lymphatic invasion, vascular invasion, perineural invasion, number of lymph nodes dissected, number of axillary lymph nodes compromised, treatment with radiotherapy and/or chemotherapy, occurrence of recurrence and/or metastasis, and patient survival. Survival functions were calculated using the Kaplan-Meier method. This study was approved by the Research Ethics Committee of the Universidade Estadual do Piauí (CEP-UESPI), Teresina, Piauí, Brazil, opinion number 4.311.835. Results: The mean age of the patients was 58.66 years. The mean tumor size was 4.6 cm. There was a predominance of invasive carcinoma of the non-special histological type (10–83.33%), followed by invasive lobular carcinoma (1–8.33%) and invasive tubular carcinoma (1–8.33%). As for lymphovascular invasion, 6 (50%) patients had vascular invasion, 7 (58.33%) had lymphatic invasion, and 3 (25%) had perineural invasion. The mean number of LAX compromised was 13.17, while the mean number of lymph nodes dissected was 20.25. Of the 12 patients, 9 were treated with radiotherapy (75%) and 10 were treated with chemotherapy (83.33%). Of the total, 6 (50%) patients had some form of recurrence, of whom 4 progressed to death. Distant metastasis occurred in 4 (30%) patients. Conclusion: The survival rate in a time interval of 5 years for patients with 10 or more compromised axillary lymph nodes was 51.6%.
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Ewald, Andrew J. "Quantitative real-time analysis of collective cancer invasion and dissemination." In SPIE Sensing Technology + Applications, edited by Harold H. Szu, Liyi Dai, and Yufeng Zheng. SPIE, 2015. http://dx.doi.org/10.1117/12.2191515.
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Kajander, Aleksi. "Russian Invasion of Ukraine 2022: Time to Reconsider Small Drones?" In 2023 15th International Conference on Cyber Conflict: Meeting Reality (CyCon). IEEE, 2023. http://dx.doi.org/10.23919/cycon58705.2023.10181494.
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Bertolini, Andre C., Vanessa Simoes, Marianna Dantas, and Patrick Pereira Machado. "USING PROXY SIMULATOR FOR RESERVOIR ZONE SELECTION AND REDUCING THE FORMATION TESTER CLEANUP OPERATIONAL TIME." In 2021 SPWLA 62nd Annual Logging Symposium Online. Society of Petrophysicists and Well Log Analysts, 2021. http://dx.doi.org/10.30632/spwla-2021-0114.
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The filtrate contamination cleanup time on a complex carbonate well using a traditional wireline formation tester (WFT) tool can vary from a couple of hours to over half a day. The method proposed aims at reducing operational time to collect a low-contamination formation fluid sample by determining regions with a smaller depth of invasion using a forward model simulation that considers static and dynamic formation properties to predict the radial profile of invasion. The mud filtrate invasion process was modeled considering the static and dynamic properties of the near-wellbore region in an industry reference reservoir simulator, and it integrates three mechanisms for fluid flow: Darcy’s law, material balance, and capillary pressure. The physical robustness of the reservoir simulator was united to a data-driven model to reduce the computational cost. This proxy model is based on a trained neural network with a broad range of scenarios to predict the numerical simulation results with high accuracy. The invasion estimation from the model is then used to predict the filtrate cleanup time using an industry consolidated numerical modeling. One of the variables influencing most of the cleanup time is the depth of mud filtrate invasion. Thus, reducing this time is a determinant for the WFT operational efficiency. The model for mud invasion has been successfully tested on a complex carbonate well, and the results for the depth of mud invasion were comparable to the results obtained with a commercial data-driven inversion using multiple resistivity channels. The estimated cleanup time using the results of depth of invasion predicted by the forward model has been compared and matched with real carbonate sampling stations, and there was a high correlation indicating that zones with lower depth of invasion required less cleanup time. Besides, using the history-matched cases, different WFT technologies such as single and radial probes, focused, unfocused, and dual-packer WFT inlets were evaluated, showing a high potential for reduction of operational time when properly planned and selected for the specific type of reservoir. The proposed methodology is a viable method for understanding the clean-up behavior in different reservoir scenarios using different WFT technologies. The innovation of this method relies on the data calibration using basic and advanced petrophysical properties through a data-driven model based on a trained neural network to reduce the uncertainty in the predicted invasion radial profile and the WFT cleanup time. The reliability on the theoretical results was increased using real data calibration, and this calibrated theoretical model has been used to guide the sampling depth selection, saving operational time.
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Qatari, Ammar. "Evaluation of Real-Time and Post-Drilling Petrophysical Data Acquisition Impact on Wellbore Stability and Mechanical Rock Integrity." In International Petroleum Technology Conference. IPTC, 2024. http://dx.doi.org/10.2523/iptc-23354-ms.
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Abstract The objective of this paper is to examine filtrate and mud solids invasion effect on wellbore stability and rock mechanical integrity. A stable wellbore depends on the mechanical and chemical interaction between the wellbore fluid and the walls of the wellbore. Excessive wellbore pressure can cause lost circulation and low pressure of the wellbore can cause blowout or collapse. Multiple factors affect mechanical integrity of the rock including the time at which the acquisition of rock mechanical data was taken in the subsurface. The impact of invasion is measured by the exploitation of real-time and post-drilling petrophysical data. A thorough investigation of invasion and its effect on rock mechanical properties is performed to establish a full understanding of the association between time dependency and rock integrity. A mechanical earth model (MEM) is built utilizing petrophysical data acquired in both real-time and post-drilling. Mechanical properties are then cross checked with core measurements to examine the accuracy of the results. The effect of invasion is then highlighted showcasing the time dependency effect on both wellbore stability and rock mechanical integrity. Leveraging real-time and post-drilling petrophysical data across abrasive sandstone formation is key to investigate invasion effects. The effects were witnessed in the readings of resistivity. Separation of deep, medium, and shallow resistivities were observed highlighting the invasion effect due to the time passed after the drilling process and before logging the section. When it comes to invasion effects on strength of the rock, an (MEM) was run on a well with both LWD and wireline acoustic data. Fracture point was analyzed for the effects of invasion. A data comparison is highlighted showcasing the effect of time on the integrity of the rock. Capillary force and osmotic pressure effects are examined and cross checked with the logged data and wellbore stability impact. This paper examines the direct impact of invasion on the mechanical properties of the rock along with wellbore stability. Complex formations can be problematic in lithology during the drilling operation where it might be capable of creating issues such as stuck pipe. The geomechanics of borehole stress has a direct impact on the hazards and problems encountered during drilling operation which causes inefficiency in terms of time and cost spent operationally. The full understanding of invasion effect is a potential solution to such issues.
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Huang, Chun-Hao, and Kin Fong Lei. "Real-Time and Non-invasive Measurement of 3D Cancer Cell Invasion Process under IL-6 Cytokine Stimulation." In 2019 IEEE 13th International Conference on Nano/Molecular Medicine & Engineering (NANOMED). IEEE, 2019. http://dx.doi.org/10.1109/nanomed49242.2019.9130623.
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Roddy, Meagan, John Rauch, Lindy O’Clair, and Daniel M. Appledorn. "Abstract 5084: Real-time, quantitative cellular analysis of migration and invasion." In Proceedings: AACR 107th Annual Meeting 2016; April 16-20, 2016; New Orleans, LA. American Association for Cancer Research, 2016. http://dx.doi.org/10.1158/1538-7445.am2016-5084.
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O'Malley, Lauren, Andrew Allstadt, Gyorgy Korniss, and Thomas Caraco. "Nucleation and global time scales in ecological invasion under preemptive competition." In SPIE Third International Symposium on Fluctuations and Noise, edited by Nigel G. Stocks, Derek Abbott, and Robert P. Morse. SPIE, 2005. http://dx.doi.org/10.1117/12.609267.
Full textReports on the topic "Invasion time"
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Lisenby, Joseph W., and Jr. Repelling a Chinese Invasion of Taiwan: A Space, Forces, Time Dilemma for United States Pacific Command. Fort Belvoir, VA: Defense Technical Information Center, May 2001. http://dx.doi.org/10.21236/ada390373.
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Ying, Hongan, Jinfan Shao, Xijuan Xu, Wenfeng Yu, and Weiwen Hong. Perineural Invasion is an Indication of Adjuvant Chemotherapy in Node Negative Colorectal cancer. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, December 2021. http://dx.doi.org/10.37766/inplasy2021.12.0103.
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Review question / Objective: Perineural invasion (PNI) is a possible route for metastatic spread in various cancer types, including colorectal cancer (CRC). PNI is linked to poor prognosis. For patients with lymph node positive colorectal cancer, a number of large-scale RCT studies have confirmed that they can benefit from chemotherapy, but there are still many controversies about whether colorectal patients with negative lymph nodes need adjuvant chemotherapy. At present, there is a general consensus that patients with stage II colorectal cancer who have risk factors such as PNI+ need chemotherapy. However, there are many recent literatures that show that patients with stage II colorectal cancer with nerve invasion risk factors can not prolong the OS and DFS of patients. At the same time, chemotherapy increases the toxicity, economic and mental burden of patients. Therefore, we hope to write this review to summarize the current research findings and provide some clinical guidance on whether patients with lymph node negative colon cancer who have perineural invasion should receive chemotherapy. Condition being studied: Patients with high-risk such as PNI+ stage II colon cancer (CC) are recommended to undergo adjuvant chemotherapy (ACT). However, whether such patients can benefit from ACT remains unclear. And recently studies shown that, ACT had no significant benefit among patients with PNI.
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Aleksandrov, Pavlo. NEWS GAMES IN THE UKRAINIAN MEDIA SPACE DURING THE FULL-SCALE RUSSIAN INVASION. Ivan Franko National University of Lviv, March 2024. http://dx.doi.org/10.30970/vjo.2024.54-55.12140.
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The phenomenon of news games on the topic of the Russian-Ukrainian war of 2022-2023 has been explored in the article. During the research, a number of gaming projects from this period were analyzed, their genre and thematic specificity were determined, examples of gaming products were provided, and our own concept of a news game on the topical subject of wartime was presented. In 2022-2023, many game projects on the theme of the war in Ukraine appeared, which can be fully or partially classified as news games, conditionally dividing them into “civilian” ones, where the game character is a volunteer, an immigrant, a peaceful resident of the occupied territory, etc. and “combat”, in which the character is a Ukrainian soldier or combat unit. These games are primarily developed by gaming studios or individual game developers, rather than journalistic editorial teams, and they target an international audience (almost all the analyzed games have an English version). We categorize these news games as “entertainment” (those primarily oriented towards humor, boosting morale, and using current information or media images) and “serious” (those attempting to explain, reveal the essence, and show the war through the eyes of witnesses). According to the level of technical implementation, these games can be divided into “simple” ones (browser-based, requiring no download or payment) and “complex” ones that offer extended gameplay and are available only through subscription. Almost all gaming projects encourage donations to the Armed Forces of Ukraine and charitable funds, and the authors of paid games always emphasize that a portion of the proceeds will go towards supporting Ukrainian military personnel. Despite their significant potential, news games currently occupy a small niche in the Ukrainian media landscape. At the same time, in our opinion, the creative possibilities offered by the gaming mechanism of this interactive narrative are quite promising for explaining and revealing various socially important topics related to the Russian-Ukrainian war. Keywords: gamification; news games; game format; game research.
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Parker, Rachel, Amy Berry, Kellie Picker, David Jeffries, Prue Anderson, and Oksana Zabolotna. Learning Through Play at School Ukraine: Final Research Report. Australian Council for Educational Research, April 2024. http://dx.doi.org/10.37517/978-1-74286-738-0.
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The Learning Through Play (LTP) at School Research Study Ukraine was a four-year intervention study funded by the LEGO Foundation and implemented by the Australian Council for Educational Research (ACER) and the Ukrainian Educational Research Association (UERA). The intervention was a two-year professional learning program that blended online, and face-to-face learning called the Teacher Innovative Play Program (TIPP). The TIPP was designed based on documented evidence that reports that teachers need opportunities to experiment and reflect to change practice. The study was guided by three research questions which were revised following the full-scale invasion of Ukraine by Russian armed forces on February 24, 2022. The revised questions were as follows: 1. What are the barriers and enablers that limit and/or support effective implementation of LTP in intervention school classrooms? 2. How do teachers in intervention schools implement LTP and adjust their classroom practices to promote learners’ literacy and social and emotional development? 3. How do children’s literacy and social emotional skills compare between testing time points including prior to and during the invasion of Ukraine by Russian armed forces?
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Бєлик, Юлія Вільєвна, Василь Миколайович Савосько, and Юрій Вікторович Лихолат. Taxonomic Composition and Synanthropic Characteristic of Woody Plant Community on Petrovsky Waste Rock Dumps (Kryvorizhzhya). КДПУ, 2019. http://dx.doi.org/10.31812/123456789/3640.
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The study of taxonomic composition and ecological characteristics of wood species on devastated lands as a theoretical basis for the phytomelioration of environment remains relevant nowadays. It was discovered 32 species, 25 genera and 15 families in the course of the analysis of woody plant community from devastated lands of Petrovsky waste rock dumps. Among them, allochthonous species (59.38%) have an advantage over autochthonous (40.63%) according to the quantitative indicators. It was established, hemiapophytes predominate among apophytesspecies andneophytes predominate among anthropophytesaccording to the time of entry, according to the method of invasion ergasiophytes, according to the degree of adaptation ergasiophytes and agriophytes. The results of our analysis indicate that the investigated woody plant communitycorresponds to the conditions of localization.
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Epiphan, Jean, and Steven Handel. Trajectory of forest vegetation under contrasting stressors over a 26-year period, at Morristown National Historical Park: Focused condition assessment report. National Park Service, March 2023. http://dx.doi.org/10.36967/2297281.
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The Jockey Hollow section and the New Jersey Brigade Area of Morristown National Historical Park (MORR) are predominantly comprised of upland oak-hickory forests that have regrown over the past 200 years from previous land uses. The forest is being damaged by two major stressors, a large population of white-tailed deer and an abundance of non-native, invasive shrubs and herbaceous species. This study explores changes to the forest over 26 years and suggests management techniques to avoid future degradation. The forest is typical of many upland stands in the region, and studies here would be applicable to many lands controlled by the National Park Service and to many public and private land owners. In 1995, 18 vegetation experimental plots were established in the forest, each 20 x 20 m. Ten plots were in areas that had no non-native, invasive plants. The other eight plots had invasive species. All trees, shrubs and a sampling of herbs were recorded in each of the 18 plots. At that time, no GPS technology was available and handwritten maps were used to record locations. The plots were revisited and resurveyed in 2001; however, only 13 plots were found. This 2021 study is a new survey of the plot conditions. The investigators were able to relocate 17 of the original plots. New GPS locations were recorded for these 17 plots to facilitate future studies. The goal of the study was to test if changes over 26 years in forest conditions differed between the original invaded plots as compared to the uninvaded plots. Also, these data will allow us to measure the progress of invasion into previously uninvaded areas. Together, these results will allow the forest managers to focus attention on the most aggressive plant invaders and to understand the fate of this forest type that is being challenged by deer and non-native plants. Over the last 26 years there has been no hunting for deer here. Also, the plots were not within the few deer exclosures at MORR; deer were able to enter the landscape from surrounding heavily wooded areas. Data were collected in four layers of vegetation – mature trees, saplings, shrubs, and herbaceous groundcovers. The mature trees in the invaded forest plots demonstrated declining trends. The species richness declined by 6%, the average number of trees declined by 30%, white ash and flowering dogwood had the most losses, and basal area did not increase over time because very few new saplings grew into mature tree sizes. The uninvaded plots’ mature trees also revealed a 20% declined in richness, number of trees declined by 18%, the greatest losses occurred for red maple and black birch, but basal area increased slightly due to growth of large persisting trees. Saplings in the invaded forest experienced declines over the 26 years. Species richness declined by 38%, number of native saplings decreased by 44%, and number of invasive saplings increased by 600%. In the uninvaded forest, the conditions and trends were variable. Richness decreased by 21%, no invasive saplings found, number of native saplings increased by 37% (due to increases in American beech). With American beech excluded, the number of native saplings decreased by 60%. In both forest types, the declining number of native saplings was primarily caused by excessive deer damage. For the shrub layer in invaded plots, Japanese barberry stems increased by 122% by 2001 and 276% by 2021. Barberry became the dominant species. Similarly, wineberry stands increased 486% in 2001 and 157% for 2021. It is now the second most common species. However, in the uninvaded plots there was no significant increase in the number of barberry stems and wineberry was not present in 1995 or 2001, and only averaged 1.5 stems per plot in 2021. Neither species has a significant presence now and eradication is possible. A major finding is that the process of invasion of these shrubs over 26 years is very slow. For the herbaceous plants, in the invaded plots there was a sharp decrease in cover by 2021 due to the competitive impact by the abundant invasive shrubs. The invasive Japanese stiltgrass declined 86% in cover and native Carex (sedge) species declined by 78%. In the uninvaded forest plots, stiltgrass was present in very low amounts and did not increase significantly over 26 years. The number of quadrats with any stiltgrass only increased from 3 to 5 over the 26 years. These data show that stiltgrass invades slowly in the uninvaded plots, but in the invaded plots it was greatly replaced by invasive shrubs. Overall, the rate of change of the native herb cover was slow. Together, these data suggest that currently uninvaded forest areas can be protected by monitoring and rigorously eliminating any initial invasions by non-native shrubs and herbs. Once these species reach a significant presence in number of stems or cover in a plot they explode in number. Early intervention when invasive plants first appear is the most practical management tool. Reduction of deer density will also increase the reproductive potential and sustainability of our main forest tree species. Planting of new young canopy tree species, with protection from deer, can retard the ability of invasive plants to begin new populations.
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Berdiqulov, Aziz. ECMI Minorities Blog. Russian Migrants in Central Asia – An ambiguous Reception. European Centre for Minority Issues, July 2022. http://dx.doi.org/10.53779/abpl3118.
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One of the consequences of Russia’s invasion of Ukraine is the imposition of western economic sanctions on the country and further autocratization of its political system. Both factors have resulted in a significant outward migration of Russian citizens, with Central Asia being one of frequent destinations due to the geographic proximity and widespread use of Russian language. At the same time, for many Russians the region remains a terra incognita, perceived primarily through the presence of the Central Asian labour migrants. In this blog piece, ECMI Researcher Aziz Berdiqulov examines this recent phenomenon by discussing specifically the cases of Kazakhstan and Uzbekistan as receiving countries, through the prism of different initiatives addressing the influx, social attitudes concerning the newcomers and reactions of the Russian minorities present there. Furthermore, the author tries to assess whether the new situation has the potential for changing the hitherto pattern of relations between Russians and Central Asians.
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Pauwels, Teun. The impact of the Russia–Ukraine War on ties between the Vlaams Belang in Belgium and the Putin regime. European Center for Populism Studies (ECPS), March 2023. http://dx.doi.org/10.55271/rp0013.
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The populist Radical Right party, Vlaams Belang (VB), has consistently proved itself a successful electoral competitor in Belgian politics. Already in 2004, the party obtained 24% of the vote in Flanders, focusing on issues such as immigration, Flemish nationalism, crime and law and order. As of 2007, however, the party faced increasing competition from the Flemish nationalist party Nieuw-Vlaamse Alliantie (N-VA), which has been able to present itself as a democratic alternative to the populist VB. In recent years, the VB has tended to radicalize rather than moderate its tone to differentiate itself from competitors. While foreign policy has not been a salient issue within VB ideology, various party members have developed close ties to the Putin regime since 2010. For example, Filip Dewinter, a prominent member of the VB, has met Russian officials and appeared in Russian media. Following the invasion of Ukraine, the VB was forced to shift its position on Putin’s regime. The current leader, Tom Van Grieken, has admitted he was seriously mistaken about Putin. Even Dewinter has strongly condemned Putin. At the same time, the VB remains sceptical about sanctions against Russia.
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Avis, William. Ukraine Crisis and Climate and Environment Commitments. Institute of Development Studies, March 2022. http://dx.doi.org/10.19088/k4d.2022.047.
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This rapid literature review collates available literature on the impact of the Ukraine crisis on international climate and environment commitments and considerations. The review draws on a range of sources predominantly blogs, opinion pieces and snap analyses. Given the nature of the conflict, its myriad impacts and uncertain end point, this report should be reviewed with a degree of caution. As the analysis draws heavily on opinion pieces and snap analyses, these will likely be outdated relatively quickly, and some assumptions shown to be flawed. Similarly, as events evolve, some analysis will become redundant. The impact of Russia’s invasion of Ukraine on international climate and environment commitments and considerations will be complex and multifaceted and likely to evolve over time, key themes emerging in this report are as follows: Strategic cooperation or competition of states towards climate-related goals has long been anticipated to drive global political developments in the coming century. The nature of these volatile relationships has a determining factor on the scale, speed and final form of the transition to net zero, impacting politically, environmentally and economically. Climate change is not an isolated area of strategic concern; rather it should be understood as a pervasive condition with implications for most other areas of interstate competition and cooperation, from global trade to regulatory standards. In this sense, actors have climate-related incentives and imperatives to either cooperate or compete according to specific issue areas such as the economy or national security.
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Arévalo-Sáenz, Alejandra, Borja Ferrández Pujante, and Fernando J. Rascón-Ramírez. Peritumoral Edema in Resected Meningiomas: Study of Factors Associated with the Variability of Postoperative Duration. Science Repository, March 2024. http://dx.doi.org/10.31487/j.scr.2024.01.05.
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Background: It is well known that edema can persist after meningioma resection, and sometimes it is not resolved after this time. This study aimed to establish the relationship between a series of variables associated with meningioma or surgery, and the duration of postoperative edema. Methods: We conducted a retrospective study of 77 meningiomas resected at our institution between January 2016 and January 2018 with a maximum follow-up period of up to three years. The independent variables collected were demographics, tumor location, relationship with the sinuses (invasion/contact), relationship with arterial structures, deviation from the midline, volume (cm3), degree of initial edema, WHO histological classification, degree of atypia, degree of resection, previous embolization, and development of complications. The edema levels were classified according to the classification described by Ide et al. (1995): GR0, GR1, and GR2. Measurements were performed using FLAIR magnetic resonance sequences. Statistical analyses were performed using the SPSS 21. Results: Age (p=0.003), deviation from the midline (p=0.001), and tumor volume (p<0.001) were correlated with outcome using Spearman's test. Univariate analysis revealed that the localization (p=0.016), initial edema (p<0.001), degree of atypia (p=0.019), and presence of previous embolization (p=0.037) were statistically significant. In multivariate analysis, only age, initial edema, and embolization were significant independent predictors. Conclusion: These results suggest that the degree of initial edema, midline deviation, tumor volume, tumor location, degree of atypia, and previous embolization may be important predictors of postoperative edema duration.