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Quantifying Phonological Feature Co-occurrenceApril Lynn Grotberg (13171419) 29 July 2022 (has links)
<p>This study argues that the observed-over-expected ratio, or O/E, is an inadequate metric for measuring the strength of consonant co-occurrence in Similar Place Avoidance. I advocate for the use of Yule's Q, an odds ratio based statistic that is not influenced by the relative proportions of labials, coronals, and dorsals in the dataset. This position is advanced on general statistical and linguistic considerations as well as through the analysis of empirical data from 32 languages. </p>
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<p>Parallel typological analyses are conducted using O/E and Yule's Q. Cross-linguistic comparisons using O/E suggest that CVC sequences with two coronals are the least marked of the homorganic pairs. The same analysis using Yule's Q suggests any place of articulation may be the least/most marked in a given language; there are no cross-linguistic preferences. The disagreement between the two statistics can be accounted for by the fact that O/E is sensitive to the margin totals: coronals only appear to pattern separately from the labials and dorsals in the O/E analysis because they are considerably more frequent than are labial and dorsal segments.</p>
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<p>To advance the use of Yule's Q in the study of Similar Place Avoidance, the paper provides guidance on constructing confidence intervals, measuring/interpreting effect size, and appropriate use of significance testing. Two case studies on aspects of Similar Place Avoidance in Latin and Medieval Castilian illustrate the proposed methodology.</p>
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North American Tree Bat (Genera: Lasiurus, Lasionycteris) Migration on the Mid-Atlantic Coast—Implications and Discussion for Current and Future Offshore Wind DevelopmentTrue, Michael C. 18 January 2022 (has links)
In eastern North America, "tree bats" (Genera: Lasiurus and Lasionycteris) are highly susceptible to collisions with wind energy turbines and are known to fly offshore during migration. This raises concern about ongoing expansion of offshore wind-energy development off the Atlantic Coast. Season, atmospheric conditions, and site-level characteristics such as local habitat features (e.g., forest coverage) have been shown to influence wind turbine collision rates by bats onshore, and similar features may be related to risk offshore. In response to rapidly developing offshore wind energy development, I assessed the factors affecting coastal and offshore presence of tree bats. I continuously gathered tree bat nightly occurrence data using stationary acoustic recorders on five structures (four lighthouses on barrier islands and one light tower offshore) off the coast of Virginia, USA, across all seasons, 2012–2019. I used generalized additive models to describe nightly tree bat occurrence in relation to multiple factors. I found that sites either indicated maternity or migratory patterns in their seasonal occurrence pattern that were associated with local roosting resources (i.e., presence of forest). Across all sites, nightly occurrence was negatively related to wind speed and positively related to temperature and visibility. Using predictive performance metrics, I concluded that the model was highly predictive for the Virginia coast. My findings were consistent with other studies—tree bat occurrence probability and presumed mortality risk to offshore wind-energy collisions is highest on nights with low wind speed, high temperature and visibility during spring and fall. The high predictive model performance I observed provides a basis for which managers, using a similar monitoring and modeling regime, could develop an effective curtailment-based mitigation strategy.
Although information at fixed points is helpful for managing specific sites, large questions remain on certain aspects of tree bat migration, in part because direct evidence (i.e., tracking of individuals) has been difficult to obtain so far. For instance, patterns in fall behavior such as the timing of migration events, the existence of migratory pathways, consistencies in the direction of travel, the drivers of over-water flight, and the activity states of residents (or bats in stopover) remain unstudied in the mid-Atlantic. The recently established Motus Wildlife Tracking System, an array of ground-based receiver stations, provides a new technique to track individual bats via the ability to detect course-scale movement paths of attached very high frequency radio-tags. To reveal patterns in migration, and to understand drivers of over-water flight, I captured and radio-tagged 115 eastern red bats (Lasiurus borealis) and subsequently tracked their movements. For the bats with evidence of large movements, most traveled in a southwesterly direction whereby paths were often oriented interior toward the continental landmass rather than being oriented along the coastline. This observation challenges earlier held beliefs that bats closely follow linear landscape features, such as the coast, when migrating. I documented bats traveling across wide sections of the Chesapeake and Delaware bays confirming the species' ability to travel across large water bodies. This behavior typically occurred in the early hours of the night and during favorable flying conditions such as low wind speeds, warm temperatures, and/or during sudden increases in temperature associated with the passage of cold fronts. For bats engaging in site residency through the fall, the proportion of night-hours in which bats were in a resting state (and possibly torpor), increased with colder temperatures and the progression of the fall season. My study demonstrated that bats may be at risk to offshore wind turbine collisions off the mid-Atlantic, but that this risk might be minimal if most bats are migrating toward the interior landscape rather than following the coast. Nonetheless, if flight over large water bodies such as Chesapeake and Delaware bays is a viable proxy for over-ocean flight, then collision risk at offshore wind turbines may be somewhat linked to atmospheric, seasonal timing, or other effects, and therefore some level of predictable and manageable with mitigations options such as smart curtailment. / Master of Science / In eastern North America on the mid-Atlantic and Northeast coasts, a group of bat species named "tree bats" engage in seasonal migrations—generally shifting north in spring and south in fall. On the East coast, it is known that eastern red bats and silver-haired bats will occasionally fly over the ocean during these periods. Although this behavior is somewhat hard to explain due to their reliance on trees for day-time roosting, it raises concern conservation concerns due to the current and future rapid development of offshore wind energy turbines. This is compounded by the fact that collision rates with turbines are high for this species group in general and highest in the fall migratory season. The fall period is also when bats may be attracted to tall structures such as turbines and when most offshore flight happens. Nevertheless, bats are sensitive to atmospheric conditions such as temperature and wind speed, and other factors influence their propensity to fly (and be at risk to turbine strikes). So, understanding these drivers may aid in understanding the conditions that present the highest risk to strike at offshore wind turbines.
In response to rapid offshore wind development in the Atlantic, I recorded bats in coastal Virginia, USA from 2012–2019, using acoustic monitors—devices that collect the echolocation vocalizations of bats. I found that tree bat visitation offshore or on barrier islands was associated with wind speed, temperature, visibility, and seasonality. Using statistical modeling, I developed a predictive tool to assess occurrence probabilities at varying levels of wind speed, temperature, and seasonality. Probability of occurrence and therefore assumed risk to collision was highest on high temperature and visibility nights, low wind speed nights, and during the spring and fall seasons. Therefore, I suggest a similar modeling regime could be used to predict the occurrence of bats at offshore wind sites to inform potential mitigation efforts.
Next, I attempted to answer broader questions about tree bat migratory behavior such as attempting to identify migratory pathways throughout the mid-Atlantic. The Motus Wildlife Tracking System gives researchers the ability to directly track individuals over long-distances with radio-transmitters and ground-based receiver stations. Using Motus, I captured and radio-tagged >100 tree bats, which were of majority eastern red bats and tracked their movements throughout the mid-Atlantic region. I found that movements were not oriented along the coastline, which challenged previously held beliefs that bats use the coast during migration. Tree bats also traversed large bodies of water, the Chesapeake and Delaware bays, confirming the ability for this group to fly over-water. Through statistical modeling, I found that these over-water bouts were early in the night and related to advantageous flying conditions such as low wind speeds, high temperatures, and during periods of sudden temperature increase (which could be linked to the passage of cold weather fronts). Offshore collision risk to tree bats may be somewhat minimal if most bats orient inland, rather than coastal for their migration movement. Nevertheless, for those bats that do fly over the ocean, if crossing large waterbodies is a viable proxy for over-ocean movement, then this behavior is linked to multiple factors, of which can be used to predict occurrences and even potentially predict and manage risk to collision.
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L’effet des facteurs de risques statiques et dynamiques sur la trajectoire de victimisation des femmes en contexte de violence conjugaleVéronneau, Jade 08 1900 (has links)
Plusieurs travaux montrent que la violence conjugale est un phénomène dynamique, avec des épisodes de violence s'inscrivant dans une séquence d'événements. Toutefois, nos connaissances sur les circonstances de vie qui influencent la violence à travers le temps restent limitées. De plus, la recherche porte principalement sur violence physique. Plusieurs travaux mettent de l’avant que la co-occurrence des différentes formes de violence est la norme. Or, le lien entre les différentes formes de violence au sein des trajectoires individuels reste largement méconnu. Cette étude vise à reconstruire la trajectoire de victimisation des femmes afin d’adresser certaines lacunes quant à nos connaissances sur les violences au sein du couple. On s’intéresse plus particulièrement à prédire l’occurrence de quatre formes de violence (physique grave, psychologique intense, sexuelle et économique) au sein des trajectoires individuelles selon l’effet les caractéristiques individuelles des victimes (facteurs statiques) et les circonstances de vie (facteurs dynamiques). Cette étude se concentre particulièrement sur l'effet des périodes de grossesse et de séparation sur la dynamique de la violence conjugale, des aspects peu explorés jusqu'à présent. De plus, elle cherche à déterminer si les antécédents de violence durant l'enfance sont prédictifs de la violence conjugale à l'âge adulte. Les données proviennent d'entretiens structurés menés entre 2014 et 2016 auprès de 75 femmes victimes de violence conjugale et référées par divers organismes tels que maisons d'hébergement, les tribunaux municipaux, les centres d'aide aux victimes d'actes criminels, les centres de thérapie et les maisons de transition. Les trajectoires individuelles ont été reconstruites à l'aide de la méthode des calendriers d'histoire de vie. Les résultats mettent en évidence les facteurs statiques et dynamiques associés à chaque type de violence, révélant à la fois des distinctions et des similitudes entre ces formes de violence. Ils soulignent également une forte co-occurrence entre les différentes formes de violence, indiquant que les aborder de manière isolée est insuffisant pour en comprendre l'occurrence individuelle. Ces résultats fournissent des informations précieuses pour l'élaboration de recommandations en matière de prise en charge et de prévention de la violence conjugale. / Several studies show that intimate partner violence is a dynamic phenomenon, with
episodes of violence forming part of a sequence of events. However, our knowledge of the life
circumstances that influence violence over time remains limited. Moreover, the research mainly
focuses on physical violence. Several studies highlight that the co-occurrence of different forms
of violence is the norm. However, the link between the different forms of violence within
individual trajectories remains largely unknown. This study aims to reconstruct women's
victimization trajectories to address some of the gaps in our knowledge of intimate partner
violence. We are particularly interested in predicting the occurrence of four forms of violence
(severe physical, intense psychological, sexual, and economic) within individual trajectories
based on the effect of individual victim characteristics (static factors) and life circumstances
(dynamic factors). This study focuses on the effect of pregnancy and separation on the dynamics
of domestic violence, aspects that have been little explored to date. In addition, it seeks to
determine whether a history of violence in childhood is predictive of intimate partner violence
in adulthood. The data was derived from structured interviews conducted between 2014 and
2016 with 75 women who had experienced intimate partner violence in the past 36 months and
were referred by various organizations such as shelters, municipal courts, crime victim’s
assistance centers, therapy centers and halfway houses. The individual trajectories were
reconstructed using the life history calendar method, a proven approach to the study of criminal
careers and victimization that allows us to contextualize events and understand the underlying
dynamics of victimization. The analysis is carried out using multilevel modelling, enabling
individual characteristics and life circumstances to be examined. The results highlight the static
and dynamic factors associated with each type of violence, revealing both differences and
similarities between these forms of violence. They also highlight a strong co-occurrence
between the different forms of violence, indicating that addressing them in isolation is
insufficient to understand their individual occurrence. These findings provide valuable
information for the development of recommendations for the intervention and prevention of
intimate partner violence.
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Applying ecological models to positive interactions among lotic fishes: implications for population and community regulation at multiple spatial scalesPeoples, Brandon Kevin 06 May 2015 (has links)
Positive biotic interactions such as mutualism, commensalism and facilitation are ubiquitous in nature, but historically have received considerably less research attention than negative interactions such as competition, predation and parasitism. The paucity of research on positive interactions is particularly evident in stream ecosystems and in vertebrate communities. Stream fishes clearly provide an ideal system for advancing research on positive interactions. Many minnows (Cyprinidae) of eastern North America engage in a potentially mutualistic reproductive interaction known as nest association, in which individuals of one species (nest associates) spawn in nests constructed by host species. In nest association, hosts provide unsilted gravel substrate for spawning nest associates, and increased parental care to associate broods. High associate: host egg ratios can create a dilution effect, reducing the probability that host eggs will be preyed upon by egg predators. Nest associative interactions are common, but are relatively understudied compared to other interactions among stream fishes.
The goals of this study were to apply general ecological models to this novel system to (a) gain new insight into the mechanisms structuring nest associative stream fish communities, and (b) to use inference from stream fish communities to potentially expand and improve the general ecological models. These goals required completion of three objectives, including (1) examining the influence of abiotic and biotic contexts on reproductive behavior and fitness outcomes between a cyprinid host and associate, using the biological markets model to generate predictions; (2) examining the utility of the nest web framework (previously only used for cavity nesting vertebrate communities) and the stress gradient hypothesis (previously applied almost exclusively to plant communities) for predicting which associate species spawn on nests built by various nest building species, and the consequences of these choices, respectively; and (3) using two-species occupancy modeling to determine the relative influence of biotic interactions and habitat covariates on the co-occurrence of a host and two nest associates.
To accomplish these goals, I conducted a large-scale experiment to manipulate presence of mutualists (Nocomis leptocephalus, host; Chrosomus oreas, associate), egg predators (biotic context) and habitat quality (abiotic context). I conducted behavioral nest observations and conducted repeated stream fish stream fish community surveys to collect demographic data. I constructed a nest web from observational data, and implemented structural equation modeling through an information-theoretic framework to identify nest web plausibility across a large spatial extent. I tested some predictions of the stress gradient hypothesis by regressing juveniles-per-nest and a metric of cyprinid community structure on a composite measure of physical stress (scaled gradients of catchment-scale agricultural land use and catchment area). I used two-species occupancy modeling to model co-occurrence of N. leptocephalus hosts and two associates, C. oreas and Clinostomus funduloides, and used an information-theoretic framework to compare hypotheses representing the importance of biotic interactions, habitat covariates or both at determining species co-occurrence.
Results corroborated some (but not all) model predictions, and identified room for improvement in each of the general models. Nest associative spawning by C. oreas was not context dependent; C. oreas did not spawn in the absence of a reproductively active male N. leptocephalus at any treatment level. However, the net fitness outcome of host and associate species was mutualistic, and the interaction outcome switched from commensalistic to mutualistic with abiotic context. N. leptocephalus reproductive success was improved by C. oreas presence in less-silted habitats, but not in heavily-silted habitats. This is most likely because broods were subject to predation in both habitat types, but were also negatively affected by siltation in silted habitats. Accordingly, egg dilution by associates was not sufficient to support a mutualistic relationship in less favorable habitats. Results suggest that the biological markets model may be a useful tool for predicting fitness outcomes of nest associative mutualism, but may not be as useful for predicting the behavioral outcomes of obligate mutualisms. Future applications of the biological markets model should carefully consider species traits, specifically the degree to which trading behavior is obligate for participants. Future work with this model will yield more insight by considering highly facultative associates.
Nest webs constructed from nest observational data suggested an interaction topology in which strong (nearly-obligate) associates relied most frequently on N. leptocephalus nests, and less frequently on nests constructed by Campostoma anomalum. Weak (facultative) associates were seldom associated with nests constructed by either species, and probably spawned before hosts began nesting activity. Structural equation models corroborated this topology throughout the New River basin, although some less-supported model evidence specified some nest association by weak associates. Juveniles-per-nest of strong associates responded positively to physical stress, while this metric for other cyprinid reproductive groups showed no relationship. Proportional representation of Nocomis and strong associates also increased predictably with physical stress. This study suggests that the nest web framework can be informative to systems outside the ones for which it was developed; future studies may be able to use this framework to better understand the role of habitat-modifying species in communities other than cavity nesting terrestrial vertebrates and nest associative stream fishes. This work extended the nest web framework by (a) modeling the outcomes of interactions instead of the interactions themselves, and (b) by using structural equation modeling to test nest web predictions with an information-theoretic framework. This study also suggests that the stress gradient hypothesis can be useful for understanding interaction dynamics in vertebrate communities; this represents the first direct evidence that this model can be used in vertebrate communities. Further, I demonstrate that the stress gradient hypothesis may be extended to predict community structure. However, more research in a diversity of systems will be needed to determine the extent to which this can be applied.
This study provides some of the first evidence of large-scale positive co-occurrence patterns in vertebrates. However, the precise roles of habitat covariates and biotic interactions were species-specific. Occupancy results suggest that co-occurrence between N. leptocephalus and nest associate C. funduloides is driven only by reproductive behavioral interactions. Alternatively, evidence suggests that co-occurrence between N. leptocephalus and C. oreas is driven by both nest association and habitat covariates. That two-species occupancy modeling can be a useful tool for comparing difficult-to-test hypotheses involving biotic interactions at large spatial scales. This study represents the first quantitative, multi-scale treatment of positive interactions in stream ecosystems.
This study demonstrates that applying general ecological models to stream fish communities can yield new insights about both the study system and the models themselves. While models of negative interactions, food webs and dispersal have been applied to stream fishes, we stand to gain much ground by also considering positive biotic interactions. In doing so, stream fish ecologists will also be able to contribute to the advancement of general ecology, and thus raise awareness for these understudied ecosystems and taxa. / Ph. D.
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Error analysis: investigating the writing of ESL Namibian learnersMungungu, Saara Sirkka 11 1900 (has links)
This study investigated common English language errors made by Oshiwambo, Afrikaans and Silozi First Language speakers. The study examined errors in a corpus of 360 essays written by 180 participants. Errors were identified and classified into various categories. The four most common errors committed by the participants were tenses, prepositions, articles and spelling. The study is important to educators and study material developers who should become aware of the kind of errors that their target learners make, so that they are in a better position to put appropriate intervention strategies into place. For learners, error analysis is important as it shows the areas of difficulty in their writing. The limitations and some pedagogical implications for future study are included at the end of this research paper. / English Studies / M. A. (TESOL)
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世界城市的概念輪廓與連結:以Flickr Tags為例 / The World Cities Concept Profiling And Concatenation:A Case Study On Flickr Tags曹期鈞, Tsao, Chi Chun Unknown Date (has links)
在這社會網路蓬勃發展之中、網際網路頻寬與速度相繼提昇的資訊年代,結合網路科技所衍生的Flickr網路相簿因應而生。Flickr提供許多API程式讓使用者或有興趣研究的專家學者能透過Flickr所收集及其所探討的議題,來觀察社會網路的變化情形。
社會網路主要是由節點以及節點間彼此相連結所形成,常見的網路模型大致可分為One-mode與Two-mode兩種網路結構,而本文則採用內部同時有兩種類節點、由兩個城市與Tags共同組合而成的Two-mode網路為基礎架構,期望藉此來闡述一個Tags系統分析法,利用Flickr使用者收集、標註之Flickr標記來與世界城市的概念輪廓相連結,透過提取城市語義分配給Flickr上照片的Tags,以及解決Part-Of-Speech (POS)、詞幹還原及雜訊處理…等問題,來達成依據排名結果分析出城市概念輪廓的最終目的。
除此之外,本文還運用了Flickr tag資料來彙整出41個城市的前100名tag,再篩選出前10名的tag,將其與相關的城市歸類一起比較。本文亦使用字詞共現指標(Tag co-occurrence)來計算與該城市的關聯性,再利用此法則來歸納出這兩個城市字詞共同出現的機會,以便於了解城市與城市之間的關連字詞組合。最後,本研究亦透過Flickr網站本身Popular Tags經由分析及匯出標籤雲的結果來與本文之實驗結果相對照,本實驗85%的吻合度驗證了可靠性。 / The Flickr Web Albums was born in the information age of social network growth, internet bandwidth and speed improvement. Users and researchers can observe the changing of social network from topics collected and studied by Flickr using API programs provided by Flickr.
The main structure of social network can be distinguished one-mode and two-mode network which is composed by nodes, generally. An approach for world cities concept profiling analysis is developed in this study by conbineing two types of nodes and two cities with tag which is the two-mode network using extracting city semantics for tags assigned to photos on Flickr, solving Part-of-Speech(POS), Stemming reduction and noise handing by collecting Flickr's tags from Flickr users.
The top 100 tags were slected for 41 cities and then top 10 tags for each city were also extracted. The Tag co-occurrence was also applied to analysis the relationship of cities. Then the connection between the cities can be understood by the result of tag co-occurrence opportunities. The 85% accurancy was demonstrated by comparing the result of analysised and exported Popular Tags from Flickr Website service and the result of experiments in this study.
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Civilinės atsakomybės draudimo sutarčių ypatumai ir jų įgyvendinimo problemos / Civil Liability Insurance Contract Features and Implementation IssuesVegys, Šarūnas 07 February 2011 (has links)
Civilinės atsakomybės draudimo sutarčių institutas yra sąlyginai nauja sritis civiliniuose teisiniuose santykiuose. Kai kurie tokių sutarčių probleminiai aspektai išryškėja tik taikant konkrečias sutartis praktikoje, todėl šalyse kaip Lietuva, kur draudimo teisės tradicijos nėra labai gilios, šio instituto ypatumai ir įgyvendinimo problemos yra ganėtinai aktualūs. Nors CAD sutarties samprata atskleista pakankamai išsamiai, teisės mokslininkai iki šiol vieningai nesutaria dėl šios rūšies draudimo sutarčių prigimties, draudiminiams įvykiams taikomų kriterijų bei pačių santykio dalyvių teisių ir pareigų apimties pagal CAD sutartį. Nesant išsamaus teisinio reglamentavimo teismams tenka vadovautis bendraisiais civilinės teisės principais, o tokia praktika, nors ir pasiekusi aukščiausios instancijos teismus, neišvengia subjektyvaus atskirų situacijų vertinimo. CAD sutarties aiškinimas teismuose, kai silpnesnioji sandorio šalis, sudariusi sutartį prisijungimo būdu, yra neadekvačiai griežtai saugoma nuo ekonomiškai stipresnės šalies įtakos, neatsižvelgiant į CAD sutarties sąlygas, galų gale atsisuka prieš pačią silpnesniąją šalį. Siekiant išvengti tokios praktikos bei įtvirtinti kokybiškai vertingą CAD sutarčių taikymą, būtina atsižvelgti į šio instituto specifinį draudimo objektą – draudėjo interesą apsidrausti nuo galimos rizikos, susijusios su prievolės trečiajam asmeniui įvykdymu ir iš to kilusių pasekmių. Tik įvertinus CAD sutarčių ypatumus galima pasiekti sąžiningą ir teisinės... [toliau žr. visą tekstą] / Civil liability insurance contracts institute is a relatively new field of civil legal relations. Some of the problematic aspects of such contracts are revealed only under practice, and so in countries such as Lithuania, where tradition of insurance law is not very intense, the institute features and implementation issues are quite relevant. Although the concept of CAD contract disclosed in sufficient detail, law scientists still do not agree unanimously on the nature of insurance contracts, criteria applicable to the occurrences and the amount of rights of the participants under the CAD contract. In the absence of a comprehensive legal framework, courts have to follow general principles of civil law and even the supreme instance courts cannot avoid the subjective evaluation of individual situations. CAD contract interpretation in courts, where a weaker party of the contract is inadequately strictly protected from economically stronger party influence regardless to the terms of the contract, will eventually turn against the weaker party itself. In order to avoid such practice and establish valuably qualified application of CAD contracts, must take into account the specifics of the object of institute - policyholders interest to insure the risks associated with obligations to a third party and the performance of the resulting consequences. Only when the features of the CAD contracts are evaluated we are able to achieve a fair and on the base of the legal state established... [to full text]
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Developmental trajectories of marijuana use and psychological distress : exploring the co-occurrence of these phenomena in early adolescenceZiba-Tanguay, Kali 01 1900 (has links)
Le début de l’adolescence est une période de changements rapides où la détresse psychologique et l’expérimentation de la marijuana sont choses fréquentes. Certaines études longitudinales ont démontré que ces deux phénomènes ont tendance à se manifester conjointement tandis que d’autres n’ont pu observer de tel lien. Ces résultats divergents suggèrent que plusieurs questions persistent concernant la nature de cette relation. Cette thèse a pour objectif d’explorer la consommation de marijuana et la détresse psychologique en début d’adolescence afin de mieux saisir les changements à travers le temps, ainsi que d’examiner si ces deux problématiques évoluent conjointement et s’influencent réciproquement. Un échantillon de 448 adolescents garçons et filles fréquentant deux écoles secondaires de Montréal, ont été suivi de secondaire I à secondaire III. De 1999 à 2001, les participants ont complété un questionnaire à chaque année de l’étude incluant des mesures portant sur la consommation de marijuana et la détresse psychologique (IDPESQ-14).
Un modèle de mixture semi-paramétrique (Nagin, 2005) a été utilisé afin d’identifier les trajectoires développementales de la consommation de marijuana et de détresse psychologique. Des analyses ont également été effectuées afin d’établir les liens d’appartenance entre chacune des trajectoires de consommation identifiées et la détresse psychologique lors de la première année de l`étude, ainsi qu’entre chacune des trajectoires de détresse psychologique et la consommation de marijuana en première année du secondaire. Finalement, des analyses de trajectoires jointes ont été effectuées afin de déterminer l’interrelation entre la consommation de marijuana et la détresse psychologique.
Les résultats de notre étude suggèrent qu’il existe une grande hétérogénéité au niveau de la consommation de marijuana et la détresse psychologique. Trois trajectoires développementales ont été identifiées pour la consommation de marijuana: consommation légère, consommation grandissante et consommation élevée et stable. Trois trajectoires ont également été observées pour la détresse psychologique : basse, moyenne et élevée. Nos résultats démontrent la présence d’un lien entre la détresse psychologique rapportée lors de la première année de l’étude et les trajectoires de consommation problématiques. Ce lien a également été observé entre la consommation de marijuana rapportée lors de première année de l’étude et les trajectoires problématiques de détresse psychologique.
Les analyses de trajectoires jointes démontrent la présence d’une concordance entre la consommation de marijuana et la détresse psychologique. Cette interrelation est toutefois complexe puisque les trajectoires de détresse psychologique élevée sont associées à un niveau de consommation de marijuana plus problématique mais l’inverse de cette association est moins probable. Notre étude met en lumière la nature asymétrique de la concordance entre la consommation de marijuana et la détresse psychologique. / Early adolescence is period of rapid changes where psychological distress and marijuana use experimentation are common occurrences. Longitudinal studies examining the association between these two phenomena have provided mixed results and many questions prevail regarding the nature of this association. The purpose of this study is to examine the patterns of co-occurrence between marijuana use and psychological distress in early adolescence. A sample of 448 adolescent boys and girls attending two high schools in Montreal, Canada was followed from Grade 7 to 9. From 1999 to 2001, the participants completed an annual survey which included measures of marijuana use and psychological distress (IDPESQ-14). Using a semi-parametric group based modeling strategy, the study has for objectives to establish the developmental trajectories of marijuana use and psychological distress in early adolescence, to explore how marijuana use or psychological distress measured at baseline is associated with various developmental trajectories and to examine the interrelationship of these two phenomena as they concurrently develop over the span of our study.
Our results provide evidence that marijuana use and psychological distress are phenomena with great heterogeneity as they develop over time. We identified 3 trajectories of marijuana use: Light Users, Increasers and High Chronics and 3 trajectories of psychological distress: Low, Medium and High. Our findings also demonstrate that adolescents who reported psychological distress at baseline were more likely to follow problematic trajectories of marijuana use when compared to light users and the reverse of the association was also true since adolescent who reported marijuana use at baseline were more likely to follow an elevated trajectory of psychological distress. Our joint trajectory analysis demonstrated that the developmental patterns of co-occurrence of marijuana use and psychological distress are complex. Our study provides evidence that adolescents following a trajectory of elevated psychological distress are at increased risk of also following a trajectory of elevated marijuana use but adolescents following a problematic trajectory of marijuana use are not necessarily at greater risk of following an elevated trajectory of psychological distress. Our study highlights the presence of an asymmetrical relationship between marijuana use and psychological distress in early adolescence.
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Ocorrência de Enterobacter sakazakii no ambiente de lactários de Maternidades da Grande São Paulo / Occurrence of Enterobacter sakazakii in the nursery environment of maternity hospitals in Greater São PauloPalcich, Gabriela 18 July 2007 (has links)
Enterobacter sakazakii é um bacilo Gram-negativo, pertencente à família Enterobacterieceae. Este microrganismo vem ganhando a atenção das autoridades de saúde pública ao redor do mundo, não tanto pela morbidade, que é baixa, mas pela elevada taxa de mortalidade que varia de 40-80%. O patógeno afeta principalmente recém-nascidos de baixo peso e bebês com até seis meses de idade. Em comum, estas crianças têm o fato de serem alimentadas com fórmula infantil desidratada, a base de leite. Em nosso país ainda não existem muitos estudos sobre a ocorrência deste patógeno em fórmulas infantis, nem no ambiente de preparo das mesmas. O objetivo deste trabalho foi avaliar as condições de produção de mamadeiras para recém-nascidos em maternidades da Grande São Paulo, além de determinar a população de E. sakazakii em fórmulas infantis desidratadas e reidratadas. A população de Enterobacteriaceae e a presença de E. sakazakii também foram avaliadas em amostras ambientais, de utensílios e mão de manipuladores. Avaliou se ainda o comportamento do patógeno em fórmula infantil reidratada simulando as condições de oferecimento aos bebês. Coletou-se amostras de três hospitais maternidades diferentes (A-escola/B-público/C-particular) e analisou-se a presença de E. sakazakii usando método ISO. Para fórmulas desidratadas e reidratadas usou-se a mesma metodologia e a técnica de número mais provável (NMP). A população de Enterobacteriaceae foi determinada usando-se PetrifilmTM 3M. E. sakazakii foi detectada em duas amostras do Hospital A (na sobra da mamadeira que voltou do berçário e de uma amostra da lata lacrada da fórmula infantil desidratada. A população nesta amostra foi de 0,03 NMP/100g.) No Hospital B, foi detectada em apenas uma amostra (na esponja de lavagem das mamadeiras contaminadas). No Hospital C, E. sakazakii não foi detectada nas amostras analisadas. Quanto à população de Enterobacteriaceae nos lactários, observou-se uma variação, sendo que as amostras colhidas no hospital C foram as que apresentaram populações mais elevadas. As cepas de E. sakazakii isoladas apresentaram comportamento similar àquele da cepa padrão, ocorrendo um aumento de 2 log na população do patógeno quando simulou-se as condições de serviço das fórmulas, via naso-gástrica, aos bebês nos berçários. / Enterobacter sakazakii is a bacillus belonging to the Enterobacteriaceae family. It is considered an opportunistic pathogen that has been gaining attention from health authorities all over the world. While morbidity associated with this bacterium is low, mortality rates can range from 40-80%. The pathogen affects mainly low-birth-weight neonates (first 28 days), but babies less than 6 month old are also at risk. Powdered infant formula has been incriminated as the possible source of the microorganism to the infected babies. ln Brazil, as in several other countries, there is scarce information regarding the incidence of E. sakazakii in powdered infant formula, in reconstituted formula, and in milk kitchens areas in hospitals. The objective of this study was to evaluated the presence of E. sakazakii in the environment, utensils, handlers, powdered and rehydrated infant formula from milk kitchens from different maternity wards in Sao Paulo, Brazil. Moreover, it was evaluated the behavior of the pathogen in rehydrated infant formula. Samples were collected from 3 hospitals maternities (A-school/B-public/C-particular) and analyzed for E. sakazakii using the ISO method. For formula (powdered or rehydrated) the MPN technique was used. Enterobacteriaceae population was determined using PetrifilmTM 3M. E. sakazakii was found in one unopened formula can collected from Hospital A (0,03 MPN/100g), although the pathogen could not be detected in other cans from the same lot. E. sakazakii was also found in leftovers from one nursing bottle from the same hospital and from one cleaning sponge from Hospital B. E. sakazakii was not detected in none of the samples from Hospital C. A variation in Enterobacteriaceae population in milk kitchens was observed. Samples collected in Hospital C presented the highest population. Isolated strains of E. sakazakii presented similar behavior to standard strains, When spiked in rehidrated infant formula. A 2 log increase in the population of the pathogen was observed when simulating the conditions of formula administration to the babies by naso-gastric tubing.
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Ocorrência natural de sexuados, produção in vitro de rainhas e multiplicação de colônias em Tetragonisca augustula (Hymenoptera, Apidae, Meliponini) / Natural occurrence of sexuals, production in vitro of queens and colony multiplication in Tetragonisca angustula (Hymenoptera, Apidae, Meliponini).Prato, Mauro 04 February 2011 (has links)
Com o avanço da meliponicultura, a utilização das abelhas sem ferrão, assim como de seus subprodutos, tem abrangido novas áreas, como a polinização de culturas agrícolas. Assim, a demanda pelo aumento do número de colônias tem sido constante, porém devido ao pouco conhecimento sobre a biologia reprodutiva dessas abelhas, há dificuldade de produção de colônias em larga escala, acarretando uma séria limitação quanto à utilização comercial desses polinizadores. Buscamos com este trabalho, oferecer ferramentas que possibilitem a multiplicação de colônias de abelhas sem ferrão em grande quantidade em um curto período de tempo. Nas abelhas indígenas sem ferrão (exceto no gênero Melipona e nos casos onde ocorrem rainhas-miniatura) a quantidade de alimento ingerido pelas larvas fêmeas é o fator responsável pela diferenciação das castas, pois as larvas que se tornam rainhas ingerem mais alimento que as larvas de futuras operárias, não havendo diferença qualitativa entre o alimento fornecido às larvas que originarão ambas as castas. De acordo com este modelo de determinação de castas, buscamos estabelecer a produção in vitro de rainhas em Tetragonisca angustula oferecendo maior quantidade de alimento às larvas de operárias, induzindo seu desenvolvimento em rainhas, que após a emergência foram introduzidas em mini-colônias órfãs para verificação da sua viabilidade (fecundação natural e postura de ovos). Em condições naturais as larvas de T. angustula que se tornam rainhas e operárias recebem respectivamente 55 µL e 8 µL de alimento em média. Assim, para a produção in vitro de rainhas oferecemos 55 µL de alimento a larvas de operárias coletadas em estágio pré-alimentação de ninhos naturais e conseguimos uma taxa de sobrevivência de até 51% e de 19% na obtenção de rainhas fisiogástricas, configurando um avanço em relação à taxa natural de emergência de rainhas, que foi de 0,21%. Das mini-colônias onde foram introduzidas rainhas virgens, 41% tiveram sucesso e se tornaram colônias perenes. A utilização de larvas de operárias na produção in vitro de rainhas é possível devido ao fato de as larvas serem totipotentes, assim como a utilização de alimento coletado de células de cria de operárias/machos, pois os resultados das análises comparativas do conteúdo protéico e de aminoácidos totais e livres dos alimentos contidos em células de cria de operárias/machos e células reais mostraram não haver diferenças significativas. A utilização de alimento larval de Scaptotrigona aff. depilis na criação in vitro de rainhas de T. angustula mostrou a possibilidade de produção de rainhas viáveis com esta nova técnica embora os perfis protéicos dos alimentos larvais de ambas as espécies sejam diferentes. Os experimentos de produção in vitro de rainhas com diferentes quantidades de alimento oferecido às larvas mostraram a existência de uma quantidade limite de alimento entre 35 µL e 45 µL acima da qual todos os indivíduos se tornam rainhas e abaixo da qual todos se tornam operárias, não havendo a ocorrência de indivíduos intermediários (intercastas). Introduzindo as rainhas produzidas in vitro em mini-colônias órfãs, conseguimos o estabelecimento de 16 colônias perenes a partir de seis colônias doadoras de material no período de seis meses, o que configura um avanço de 33% em relação às técnicas tradicionais de multiplicação de colônias que conseguiriam formar, no máximo, 12 colônias no mesmo período. A verificação da freqüência de produção de sexuados nas colônias naturais ao longo do ano mostrou que os machos são produzidos sazonalmente com alta taxa no período de fevereiro a abril, e embora as rainhas possuam uma produção baixa e homogênea ao longo do ano, concluímos que aquelas produzidas no período onde ocorre maior disponibilidade de machos possuem maiores chances de serem fecundadas. Assim, foi extremamente importante sincronizar a produção in vitro de rainhas com o período de maior disponibilidade de machos, uma vez que a fecundação destas ocorreu naturalmente. A produção in vitro de rainhas e a multiplicação de colônias nas abelhas sem ferrão se tornam ferramentas importantes para as técnicas de manejo que visam obter colônias em larga escala, com emprego na polinização, meliponicultura e conservação. / With the improvement of meliponiculture, the use of stingless bees, as well as their byproducts, has comprised new areas, such as the pollination of crops. Thus, the requirement by increasing the number of colonies has been constant, but due to poor knowledge about reproductive biology of these bees, have been difficult produce colonies on a large scale, what causes serious limitations on the commercial use of these pollinators. Our goals were to offer tools that allowed the multiplication of stingless bees colonies in large quantities in a short time. In stingless bees (except in the genus Melipona and in cases where there are miniature-queens) the amount of food ingested by female larvae is the responsible feature for caste differentiation, because the larvae that will become queens must to ingest more food than the larvae of future workers, and there is no qualitative difference between the food provided to larvae of both castes. According to this model of caste determination, we aimed at to establish the in vitro production of queens in Tetragonisca angustula, offering a large quantity of larval food to the workers larvae, thus inducing their development into queens that after rearing were introduced in orphaned mini-colonies to verify their feasibility (natural mating and egg laying). Under natural conditions the larvae of T. angustula that become queens and workers receive respectively, 55 µL and 8 µL of food on average. Thus, for the in vitro production of queens we offered 55 µL of food to workers larvae collected in pre-feeding stage from natural nests and we were able to get a survival rate up to 51 % and 19% in obtaining viable queens, which is an improvement compared to 0,21% of rearing queens observed in natural hives. About 41% of mini-colonies, where viable queens were introduced were successful and have become perennial colonies. The use of workers larvae on in vitro production of queens is possible because the larvae are totipotent, as well as the use of food collected from workers/males brood cells, because the results of comparative analysis of protein content and total and free amino acids of food stored in worker/males brood cells and royal cells showed no significant differences. The use of larval food from Scaptotrigona aff. depilis on in vitro rearing of T. angustula queens showed the possibility of producing viable queens, with this new technique, although the protein profiles of larval food of both species were different. The experiments of in vitro production of queens with different amounts of food offered to the larvae showed the existence of a threshold quantity of food between 35 mL and 45 mL above which all individuals become queens and below which all individuals become workers, without the occurrence of intermediate individuals (intercaste). Inserting the queens produced in vitro in orphaned mini-colonies, we were able to establish 16 perennial colonies as from six colonies donors of material in six months, constituting an increase of 33% compared to traditional techniques of multiplication of colonies which would form up only 12 colonies in the same period. Verification of frequency of sexuals reared in natural colonies over the year showed that males are produced seasonally with high rate in the period from February to April, and although the queens have a low and homogeneous occurrence over the year, we concluded that the queens produced during the period where there is greater availability of males, have higher chances of being fertilized. Thus, was extremely important synchronize the in vitro production of queens with the period where there is greater availability of males, since fertilization of these queens occurred naturally. The in vitro production of queens and multiplication of colonies in stingless bees become important tools for handling techniques that aim to obtain colonies on a large scale, with employment in pollination, meliponiculture and conservation.
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