840 resultados para Laury, Ritva: Demonstratives in interaction: The emergence of a definite article in Finnish
Resumo:
This Master Dissertation comprises two parts: a personal reflection and an empirical study. The personal reflection reviews the process of professionalization undergone by its author throughout the Master. The empirical study tackles teacher strategies to elicit knowledge from students in the CLIL classroom and more specifically the purpose of questions in controlled patterns of teacher-student interaction. The theories of relevant authors such as Vigotsky, Mercer and Tsui are used as a framework to analyze the data presented. The analysis shows the different strategies to elicit knowledge used by the teacher and the appropriateness of her questions in the analyzed interaction
Resumo:
HIV-1 infects CD4+ T cells and completes its replication cycle in approximately 24 hours. We employed repeated measurements in a standardized cell system and rigorous mathematical modeling to characterize the emergence of the viral replication intermediates and their impact on the cellular transcriptional response with high temporal resolution. We observed 7,991 (73%) of the 10,958 expressed genes to be modulated in concordance with key steps of viral replication. Fifty-two percent of the overall variability in the host transcriptome was explained by linear regression on the viral life cycle. This profound perturbation of cellular physiology was investigated in the light of several regulatory mechanisms, including transcription factors, miRNAs, host-pathogen interaction, and proviral integration. Key features were validated in primary CD4+ T cells, and with viral constructs using alternative entry strategies. We propose a model of early massive cellular shutdown and progressive upregulation of the cellular machinery to complete the viral life cycle.
Resumo:
Abstract The object of game theory lies in the analysis of situations where different social actors have conflicting requirements and where their individual decisions will all influence the global outcome. In this framework, several games have been invented to capture the essence of various dilemmas encountered in many common important socio-economic situations. Even though these games often succeed in helping us understand human or animal behavior in interactive settings, some experiments have shown that people tend to cooperate with each other in situations for which classical game theory strongly recommends them to do the exact opposite. Several mechanisms have been invoked to try to explain the emergence of this unexpected cooperative attitude. Among them, repeated interaction, reputation, and belonging to a recognizable group have often been mentioned. However, the work of Nowak and May (1992) showed that the simple fact of arranging the players according to a spatial structure and only allowing them to interact with their immediate neighbors is sufficient to sustain a certain amount of cooperation even when the game is played anonymously and without repetition. Nowak and May's study and much of the following work was based on regular structures such as two-dimensional grids. Axelrod et al. (2002) showed that by randomizing the choice of neighbors, i.e. by actually giving up a strictly local geographical structure, cooperation can still emerge, provided that the interaction patterns remain stable in time. This is a first step towards a social network structure. However, following pioneering work by sociologists in the sixties such as that of Milgram (1967), in the last few years it has become apparent that many social and biological interaction networks, and even some technological networks, have particular, and partly unexpected, properties that set them apart from regular or random graphs. Among other things, they usually display broad degree distributions, and show small-world topological structure. Roughly speaking, a small-world graph is a network where any individual is relatively close, in terms of social ties, to any other individual, a property also found in random graphs but not in regular lattices. However, in contrast with random graphs, small-world networks also have a certain amount of local structure, as measured, for instance, by a quantity called the clustering coefficient. In the same vein, many real conflicting situations in economy and sociology are not well described neither by a fixed geographical position of the individuals in a regular lattice, nor by a random graph. Furthermore, it is a known fact that network structure can highly influence dynamical phenomena such as the way diseases spread across a population and ideas or information get transmitted. Therefore, in the last decade, research attention has naturally shifted from random and regular graphs towards better models of social interaction structures. The primary goal of this work is to discover whether or not the underlying graph structure of real social networks could give explanations as to why one finds higher levels of cooperation in populations of human beings or animals than what is prescribed by classical game theory. To meet this objective, I start by thoroughly studying a real scientific coauthorship network and showing how it differs from biological or technological networks using divers statistical measurements. Furthermore, I extract and describe its community structure taking into account the intensity of a collaboration. Finally, I investigate the temporal evolution of the network, from its inception to its state at the time of the study in 2006, suggesting also an effective view of it as opposed to a historical one. Thereafter, I combine evolutionary game theory with several network models along with the studied coauthorship network in order to highlight which specific network properties foster cooperation and shed some light on the various mechanisms responsible for the maintenance of this same cooperation. I point out the fact that, to resist defection, cooperators take advantage, whenever possible, of the degree-heterogeneity of social networks and their underlying community structure. Finally, I show that cooperation level and stability depend not only on the game played, but also on the evolutionary dynamic rules used and the individual payoff calculations. Synopsis Le but de la théorie des jeux réside dans l'analyse de situations dans lesquelles différents acteurs sociaux, avec des objectifs souvent conflictuels, doivent individuellement prendre des décisions qui influenceront toutes le résultat global. Dans ce cadre, plusieurs jeux ont été inventés afin de saisir l'essence de divers dilemmes rencontrés dans d'importantes situations socio-économiques. Bien que ces jeux nous permettent souvent de comprendre le comportement d'êtres humains ou d'animaux en interactions, des expériences ont montré que les individus ont parfois tendance à coopérer dans des situations pour lesquelles la théorie classique des jeux prescrit de faire le contraire. Plusieurs mécanismes ont été invoqués pour tenter d'expliquer l'émergence de ce comportement coopératif inattendu. Parmi ceux-ci, la répétition des interactions, la réputation ou encore l'appartenance à des groupes reconnaissables ont souvent été mentionnés. Toutefois, les travaux de Nowak et May (1992) ont montré que le simple fait de disposer les joueurs selon une structure spatiale en leur permettant d'interagir uniquement avec leurs voisins directs est suffisant pour maintenir un certain niveau de coopération même si le jeu est joué de manière anonyme et sans répétitions. L'étude de Nowak et May, ainsi qu'un nombre substantiel de travaux qui ont suivi, étaient basés sur des structures régulières telles que des grilles à deux dimensions. Axelrod et al. (2002) ont montré qu'en randomisant le choix des voisins, i.e. en abandonnant une localisation géographique stricte, la coopération peut malgré tout émerger, pour autant que les schémas d'interactions restent stables au cours du temps. Ceci est un premier pas en direction d'une structure de réseau social. Toutefois, suite aux travaux précurseurs de sociologues des années soixante, tels que ceux de Milgram (1967), il est devenu clair ces dernières années qu'une grande partie des réseaux d'interactions sociaux et biologiques, et même quelques réseaux technologiques, possèdent des propriétés particulières, et partiellement inattendues, qui les distinguent de graphes réguliers ou aléatoires. Entre autres, ils affichent en général une distribution du degré relativement large ainsi qu'une structure de "petit-monde". Grossièrement parlant, un graphe "petit-monde" est un réseau où tout individu se trouve relativement près de tout autre individu en termes de distance sociale, une propriété également présente dans les graphes aléatoires mais absente des grilles régulières. Par contre, les réseaux "petit-monde" ont, contrairement aux graphes aléatoires, une certaine structure de localité, mesurée par exemple par une quantité appelée le "coefficient de clustering". Dans le même esprit, plusieurs situations réelles de conflit en économie et sociologie ne sont pas bien décrites ni par des positions géographiquement fixes des individus en grilles régulières, ni par des graphes aléatoires. De plus, il est bien connu que la structure même d'un réseau peut passablement influencer des phénomènes dynamiques tels que la manière qu'a une maladie de se répandre à travers une population, ou encore la façon dont des idées ou une information s'y propagent. Ainsi, durant cette dernière décennie, l'attention de la recherche s'est tout naturellement déplacée des graphes aléatoires et réguliers vers de meilleurs modèles de structure d'interactions sociales. L'objectif principal de ce travail est de découvrir si la structure sous-jacente de graphe de vrais réseaux sociaux peut fournir des explications quant aux raisons pour lesquelles on trouve, chez certains groupes d'êtres humains ou d'animaux, des niveaux de coopération supérieurs à ce qui est prescrit par la théorie classique des jeux. Dans l'optique d'atteindre ce but, je commence par étudier un véritable réseau de collaborations scientifiques et, en utilisant diverses mesures statistiques, je mets en évidence la manière dont il diffère de réseaux biologiques ou technologiques. De plus, j'extrais et je décris sa structure de communautés en tenant compte de l'intensité d'une collaboration. Finalement, j'examine l'évolution temporelle du réseau depuis son origine jusqu'à son état en 2006, date à laquelle l'étude a été effectuée, en suggérant également une vue effective du réseau par opposition à une vue historique. Par la suite, je combine la théorie évolutionnaire des jeux avec des réseaux comprenant plusieurs modèles et le réseau de collaboration susmentionné, afin de déterminer les propriétés structurelles utiles à la promotion de la coopération et les mécanismes responsables du maintien de celle-ci. Je mets en évidence le fait que, pour ne pas succomber à la défection, les coopérateurs exploitent dans la mesure du possible l'hétérogénéité des réseaux sociaux en termes de degré ainsi que la structure de communautés sous-jacente de ces mêmes réseaux. Finalement, je montre que le niveau de coopération et sa stabilité dépendent non seulement du jeu joué, mais aussi des règles de la dynamique évolutionnaire utilisées et du calcul du bénéfice d'un individu.
Resumo:
Abstract : Gene duplication is an essential source of material for the origin of genetic novelty and the evolution of lineage- or species-specific phenotypic traits. The reverse transcription of source gene mRNA followed by the genomic insertion of the resulting cDNA - retroposition - has provided the human genome with a significant number of gene copies during the last ~63 million years (MYA) of primate evolution. We estimated that at least 1 new functional gene (retrogene) per MYA emerged by retroposition in the primate lineage leading to humans. Using a combination of comparative sequencing and evolutionary simulations, we obtained strong evidence of functionality for 7 primate specific retrogenes. Most of these genes are specifically expressed in testis suggesting that retroposition has contributed with genetic raw material necessary for the evolution ofmale-specific functions in primates. We characterized CDC14Bretro (identified in the previous survey) that originated from the retroposition of a cell cycle gene - CDC14B - in the common ancestor of humans and apes. We demonstrate that CDC14Bretro experienced a period of intense positive selection in the African ape ancestor. By virtue of the amino acid substitutions that occurred during this period CDC 14Bretro adapted to a new subcellular compartment in African apes. Further analyses indicate that this subcellular shift reflects the evolution of anew functional role of CDC 14Bretro. Prompted by this result, we used yeast (Saccharomyces cerevisiae) to investigate on a global scale the extent of functional diversification of duplicate genes through the subcellular adaptation of their encoded proteins. We found that duplicate proteins frequently evolved new cellular localization patterns, either by partitioning of ancestral localizations ("sublocalization"), or more frequently by relocalization to previously unoccupied compartments ("neolocalization"). Interestingly, proteins involved in processes with a wider subcellular distribution more frequently evolved new localization patterns suggesting that subcellular localization changes are dependent on progenitor gene functions. Relocated proteins adapted to their new subcellular environments and evolved new functional roles through changes of their physio-chemical properties, expression levels, and interaction partners. Our work suggests an important role of subcellular adaptation for the emergence of new gene functions.
Resumo:
RESUME : De nombreuses espèces animales vivent en groupe. Du simple grégarisme aux colonies hautement intégrées de fourmis, la vie sociale a atteint des degrés divers de complexité. Les nombreuses interactions entre membres d'une société favorisent la transmission de parasites. Cela représente un coût potentiel de la vie sociale. Cette thèse s'intéresse aux défenses permettant de réduire le coût du parasitisme dans les colonies de fourmis ainsi qu'à la manière dont le parasitisme a pu façonner certains aspects de ces sociétés. Les colonies de fourmis des bois (Forimica paralugubris) contiennent de grandes quantités de résine de conifères. Cette résine réduit la densité microbienne dans le nid et augmente la survie des ouvrières lors d'infections parasitaires. Dans cette thèse, nous montrons, d'une part, que les ouvrières collectent activement la résine et que ce comportement est plutôt préventif que curatif et, d'autre part, que la résine permet aux ouvrières une utilisation moindre de leurs défenses immunitaires. Ces résultats permettent de conclure que ce comportement réduit l'exposition au parasitisme et qu'il a une fonction adaptative. L'émergence d'un tel comportement de médication chez une espèce d'insectes sociaux illustre le fait que la socialité, bien yue provoquant une exposition accrue au parasitisme, permet également l'émergence de mécanismes sociaux de défense. II a été suggéré que la présence de plusieurs reines au sein d'un même nid (polygynie) améliore la résistance aux parasites en augmentant la diversité génétique au sein de la colonie. En accord avec cette hypothèse, nous montrons qu'une augmentation de la diversité génétique au sein de groupes expérimentaux de Formica selysi améliore leur survie lors d'une infection parasitaire. Cependant, nous suggérons également que sur le terrain, d'autres facteurs corrélés à la polygynie ont des effets antagoniques sur la résistance. Nous montrons par exemple que les ouvrières polygynes semblent avoir une capacité moindre à monter une réponse immunitaire. Certains aspects de la reproduction des fourmis ont pu également être façonnés par le parasitisme. L'accouplement n'a lieu que lors d'une courte période au début de la vie adulte, généralement à l'extérieur de la colonie. Les reines stockent ensuite le sperme et l'utilisent parcimonieusement au cours de leur vie alors que les males meurent rapidement. Nous montrons que les défenses immunitaires des reines de fourmis des bois (F. paralugubris) sont fortement affectées par l'accouplement. Ces modulations immunitaires sont probablement liées à une augmentation de l'exposition au parasitisme lors de l'accouplement ainsi qu'à des blessures copulatoires. I1 semble donc que l'accouplement soit accompagné de coûts immunitaires pour les reines. Dans son ensemble, cette thèse illustre la diversité des mécanismes de défenses contre les parasites dans les sociétés de fourmis. La vie sociale, en offrant un nouveau niveau d'interaction, permet en effet l'émergence d'adaptations originales. Cela explique probablement le grand succès écologique des espèces sociales. SUMMARY : Sociality is widespread among animals and has reached variable degrees of complexity, from loose social Groups to highly integrated ant colonies. The many interactions between members of a social group promote the spread of parasites, but social life also permits the evolution of original defence mechanisms. This thesis sheds light on how ant colonies defend themselves against parasites, and on how parasitism shapes certain aspects of these societies. Wood ants nests (Formica paralugubris) contain large amounts of conifer resin which reduces the microbial density in ant nests and enhances the survival of ants challenged by some pathogens. We show that resin is actively collected by workers and that resin collection is rather a prophylactic than a curative behaviour. Moreover, we suggest that resin reduces the use of the immune defences of workers. Altogether, these results indicate that the use of resin is a collective adaptation to prevent the spread of parasites. The emergence of medication in a social insect species illustrates that sociality does not only increase the exposure to parasites but also allows the emergence of social mechanisms to counter this threat. The number of reproducing queens per colony is a variable trait in ants. It has been suggested that polygyny (the occurrence of multiple queens within a colony), by increasing the colonial genetic diversity, improves disease resistance. In line with this hypothesis, we show that in a socially polymorphic ant (Formica selysi), an experimental increase of colony genetic diversity enhances disease resistance. However, we also suggest that factors covarying with queen number variation in the field have antagonistic effects on parasite resistance. We show for instance that polygyne workers seem to have lower immune defences. Parasites may also shape some aspects of ant queen reproductive biology. Ant queens mate at the beginning of their adult life, usually outside of the colony, and store sperm for several years to fertilize eggs. Males die shortly after mating and queens never remate later in life, which drastically reduces sexual conflicts. Moreover, mating and nest founding occur away from the collective defence mechanisms of the natal colony and might be associated with an increased risk of parasitism. We show that mating affects the immune defences of wood ant queens (F. paralugubris) in multiple ways that are consistent with mating wounds and increased risk of parasitism. We suggest that mating is associated with immunity costs in ants, despite the reduced level of sexual conflicts. Altogether, my thesis illustrates the diversity of anti-parasite mechanisms in ant societies. This sheds light on how sociality, by offering a new level of interactions, allows the evolution of original adaptations, which may explain the wide ecological success of social species.
Resumo:
OBJECTIVES: Activity of rifampicin against Propionibacterium acnes biofilms was recently demonstrated, but rifampicin resistance has not yet been described in this organism. We investigated the in vitro emergence of rifampicin resistance in P. acnes and characterized its molecular background. METHODS: P. acnes ATCC 11827 was used (MIC 0.007 mg/L). The mutation rate was determined by inoculation of 10(9) cfu of P. acnes on rifampicin-containing agar plates incubated anaerobically for 7 days. Progressive emergence of resistance was studied by serial exposure to increasing concentrations of rifampicin in 72 h cycles using a low (10(6) cfu/mL) and high (10(8) cfu/mL) inoculum. The stability of resistance was determined after three subcultures of rifampicin-resistant isolates on rifampicin-free agar. For resistant mutants, the whole rpoB gene was amplified, sequenced and compared with a P. acnes reference sequence (NC006085). RESULTS: P. acnes growth was observed on rifampicin-containing plates with mutation rates of 2 ± 1 cfu × 10(-9) (4096× MIC) and 12 ± 5 cfu × 10(-9) (4 × MIC). High-level rifampicin resistance emerged progressively after 4 (high inoculum) and 13 (low inoculum) cycles. In rifampicin-resistant isolates, the MIC remained >32 mg/L after three subcultures. Mutations were detected in clusters I (amino acids 418-444) and II (amino acids 471-486) of the rpoB gene after sequence alignment with a Staphylococcus aureus reference sequence (CAA45512). The five following substitutions were found: His-437 → Tyr, Ser-442 → Leu, Leu-444 → Ser, Ile-483 → Val and Ser-485 → Leu. CONCLUSION: The rifampicin MIC increased from highly susceptible to highly resistant values. The resistance remained stable and was associated with mutations in the rpoB gene. To our knowledge, this is the first report of the emergence of rifampicin resistance in P. acnes.
Resumo:
The emergence of chirality in enantioselective autocatalysis for compounds unable to transform according to the Frank-like reaction network is discussed with respect to the controversial limited enantioselectivity (LES) model composed of coupled enantioselective and non-enantioselective autocatalyses. The LES model cannot lead to spontaneous mirror symmetry breaking (SMSB) either in closed systems with a homogeneous temperature distribution or in closed systems with a stationary non-uniform temperature distribution. However, simulations of chemical kinetics in a two-compartment model demonstrate that SMSB may occur if both autocatalytic reactions are spatially separated at different temperatures in different compartments but coupled under the action of a continuous internal flow. In such conditions, the system can evolve, for certain reaction and system parameters, toward a chiral stationary state; that is, the system is able to reach a bifurcation point leading to SMSB. Numerical simulations in which reasonable chemical parameters have been used suggest that an adequate scenario for such a SMSB would be that of abyssal hydrothermal vents, by virtue of the typical temperature gradients found there and the role of inorganic solids mediating chemical reactions in an enzyme-like role.
Resumo:
The focus of this study is to examine the role of police and immigrants’ relations, as less is known about this process in the country. The studies were approached in two different ways. Firstly, an attempt was made to examine how immigrants view their encounters with the police. Secondly, the studies explored how aware the police are of immigrants’ experiences in their various encounters and interactions on the street level. An ancillary aim of the studies is to clarify, analyse and discuss how prejudice and stereotypes can be tackled, thereby contributing to the general debate about racism and discrimination for better ethnic relations in the country. The data in which this analysis was based is on a group of adults (n=88) from the total of 120 Africans questioned for the entire study (n=45) police cadets and (n=6) serving police officers from Turku. The present thesis is a compilation of five articles. A summary of each article findings follows, as the same data was used in all five studies. In the first study, a theoretical model was developed to examine the perceived knowledge of bias by immigrants resulting from race, culture and belief. This was also an attempt to explore whether this knowledge was predetermined in my attempt to classify and discuss as well as analyse the factors that may be influencing immigrants’ allegations of unfair treatment by the police in Turku. The main finding shows that in the first paper there was ignorance and naivety on the part of the police in their attitudes towards the African immigrant’s prior experiences with the police, and this may probably have resulted from stereotypes or their lack of experience as well as prior training with immigrants where these kinds of experience are rampant in the country (Egharevba, 2003 and 2004a). In exploring what leads to stereotypes, a working definition is the assumption that is prevalent among some segments of the population, including the police, that Finland is a homogenous country by employing certain conducts and behaviour towards ethnic and immigrant groups in the country. This to my understanding is stereotype. Historically this was true, but today the social topography of the country is changing and becoming even more complex. It is true that, on linguistic grounds, the country is multilingual, as there are a few recognised national minority languages (Swedish, Sami and Russian) as well as a number of immigrant languages including English. Apparently it is vital for the police to have a line of communication open when addressing the problem associated with immigrants in the country. The second paper moved a step further by examining African immigrants’ understanding of human rights as well as what human rights violation means or entails in their views as a result of their experiences with the police, both in Finland and in their country of origin. This approach became essential during the course of the study, especially when the participants were completing the questionnaire (N=88), where volunteers were solicited for a later date for an in-depth interview with the author. Many of the respondents came from countries where human rights are not well protected and seldom discussed publicly, therefore understanding their views on the subject can help to explain why some of the immigrants are sceptical about coming forward to report cases of batteries and assaults to the police, or even their experiences of being monitored in shopping malls in their new home and the reason behind their low level of trust in public authorities in Finland. The study showed that knowledge of human rights is notably low among some of the participants. The study also found that female respondents were less aware of human rights when compared with their male counterparts. This has resulted in some of the male participants focussing more on their traditional ways of thinking by not realising that they are in a new country where there is equality in sexes and lack of respect on gender terms is not condoned. The third paper focussed on the respondents’ experiences with the police in Turku and tried to explore police attitudes towards African immigrant clients, in addition to the role stereotype plays in police views of different cultures and how these views have impacted on immigrants’ views of discriminatory policing in Turku. The data is the same throughout the entire studies (n=88), except that some few participants were interviewed for the third paper thirty-five persons. The results showed that there is some bias in mass-media reports on the immigrants’ issues, due to selective portrayal of biases without much investigation being carried out before jumping to conclusions, especially when the issues at stake involve an immigrant (Egharevba, 2005a; Egharevba, 2004a and 2004b). In this vein, there was an allegation that the police are even biased while investigating cases of theft, especially if the stolen property is owned by an immigrant (Egharevba, 2006a, Egharevba, 2006b). One vital observation from the respondents’ various comments was that race has meaning in their encounters and interaction with the police in the country. This result led the author to conclude that the relation between the police and immigrants is still a challenge, as there is rampant fear and distrust towards the police by some segments of the participating respondents in the study. In the fourth paper the focus was on examining the respondents’ view of the police, with special emphasis on race and culture as well as the respondents’ perspective on police behaviour in Turku. This is because race, as it was relayed to me in the study, is a significant predictor of police perception (Egharevba, 2005a; Egharevba and Hannikianen, 2005). It is a known scientific fact that inter-group racial attitudes are the representation of group competition and perceived threat to power and status (Group-position theory). According to Blumer (1958) a sense of group threat is an essential element for the emergence of racial prejudice. Consequently, it was essential that we explored the existing relationship between the respondents and the police in order to have an understanding of this concept. The result indicates some local and international contextual issues and assumptions that were of importance tackling prejudice and discrimination as it exists within the police in the country. Moreover, we have to also remember that, for years, many of these African immigrants have been on the receiving end of unjust law enforcement in their various countries of origin, which has resulted in many of them feeling inferior and distrustful of the police even in their own country of origin. While discussing the issues of cultural difference and how it affects policing, we must also keep in mind the socio-cultural background of the participants, their level of language proficiency and educational background. The research data analysed in this study also confirmed the difficulties associated with cultural misunderstandings in interpreting issues and how these misunderstandings have affected police and immigrant relations in Finland. Finally, the fifth paper focussed on cadets’ attitudes towards African immigrants as well as serving police officers’ interaction with African clients. Secondly, the police level of awareness of African immigrants’ distrustfulness of their profession was unclear. For this reason, my questions in this fifth study examined the experiences and attitudes of police cadets and serving police officers as well as those of African immigrants in understanding how to improve this relationship in the country. The data was based on (n=88) immigrant participants, (n=45) police cadets and 6 serving police officers from the Turku police department. The result suggests that there is distrust of the police in the respondents’ interaction; this tends to have galvanised a heightened tension resulting from the lack of language proficiency (Egharevba and White, 2007; Egharevba and Hannikainen, 2005, and Egharevba, 2006b) The result also shows that the allegation of immigrants as being belittled by the police stems from the misconceptions of both parties as well as the notion of stop and search by the police in Turku. All these factors were observed to have contributed to the alleged police evasiveness and the lack of regular contact between the respondents and the police in their dealings. In other words, the police have only had job-related contact with many of the participants in the present study. The results also demonstrated the complexities caused by the low level of education among some of the African immigrants in their understanding about the Finnish culture, norms and values in the country. Thus, the framework constructed in these studies embodies diversity in national culture as well as the need for a further research study with a greater number of respondents (both from the police and immigrant/majority groups), in order to explore the different role cultures play in immigrant and majority citizens’ understanding of police work.
Resumo:
The emergence and spread of infectious diseases reflects the interaction of ecological and economic factors within an adaptive complex system. We review studies that address the role of economic factors in the emergence and spread of infectious diseases and identify three broad themes. First, the process of macro-economic growth leads to environmental encroaching, which is related to the emergence of infectious diseases. Second, there are a number of mutually reinforcing processes associated with the emergence/spread of infectious diseases. For example, the emergence and spread of infectious diseases can cause significant economic damages, which in turn may create the conditions for further disease spread. Also, the existence of a mutually reinforcing relationship between global trade and macroeconomic growth amplifies the emergence/spread of infectious diseases. Third, microeconomic approaches to infectious disease point to the adaptivity of human behavior, which simultaneously shapes the course of epidemics and responds to it. Most of the applied research has been focused on the first two aspects, and to a lesser extent on the third aspect. With respect to the latter, there is a lack of empirical research aimed at characterizing the behavioral component following a disease outbreak. Future research should seek to fill this gap and develop hierarchical econometric models capable of integrating both macro and micro-economic processes into disease ecology.
Resumo:
Evolution of resistance to drugs and pesticides poses a serious threat to human health and agricultural production. CYP51 encodes the target site of azole fungicides, widely used clinically and in agriculture. Azole resistance can evolve due to point mutations or overexpression of CYP51, and previous studies have shown that fungicide-resistant alleles have arisen by de novo mutation. Paralogs CYP51A and CYP51B are found in filamentous ascomycetes, but CYP51A has been lost from multiple lineages. Here, we show that in the barley pathogen Rhynchosporium commune, re-emergence of CYP51A constitutes a novel mechanism for the evolution of resistance to azoles. Pyrosequencing analysis of historical barley leaf samples from a unique long-term experiment from 1892 to 2008 indicates that the majority of the R. commune population lacked CYP51A until 1985, after which the frequency of CYP51A rapidly increased. Functional analysis demonstrates that CYP51A retains the same substrate as CYP51B, but with different transcriptional regulation. Phylogenetic analyses show that the origin of CYP51A far predates azole use, and newly sequenced Rhynchosporium genomes show CYP51A persisting in the R. commune lineage rather than being regained by horizontal gene transfer; therefore, CYP51A re-emergence provides an example of adaptation to novel compounds by selection from standing genetic variation.
Resumo:
Determining the time of emergence of climates altered from their natural state by anthropogenic influences can help inform the development of adaptation and mitigation strategies to climate change. Previous studies have examined the time of emergence of climate averages. However, at the global scale, the emergence of changes in extreme events, which have the greatest societal impacts, has not been investigated before. Based on state-of-the-art climate models, we show that temperature extremes generally emerge slightly later from their quasi-natural climate state than seasonal means, due to greater variability in extremes. Nevertheless, according to model evidence, both hot and cold extremes have already emerged across many areas. Remarkably, even precipitation extremes that have very large variability are projected to emerge in the coming decades in Northern Hemisphere winters associated with a wettening trend. Based on our findings we expect local temperature and precipitation extremes to already differ significantly from their previous quasi-natural state at many locations or to do so in the near future. Our findings have implications for climate impacts and detection and attribution studies assessing observed changes in regional climate extremes by showing whether they will likely find a fingerprint of anthropogenic climate change.
Resumo:
A clinical Klebsiella pneumoniae isolate carrying the extended-spectrum beta-lactamase gene variants bla(SHV-40), bla(TEM-116) and bla(GES-7) was recovered. Cefoxitin and ceftazidime activity was most affected by the presence of these genes and an additional resistance to trimethoprim-sulphamethoxazole was observed. The bla(GES-7) gene was found to be inserted into a class 1 integron. These results show the emergence of novel bla(TEM) and bla(SHV) genes in Brazil. Moreover, the presence of class 1 integrons suggests a great potential for dissemination of bla(GES) genes into diverse nosocomial pathogens. Indeed, the bla(GES-7) gene was originally discovered in Enterobacter cloacae in Greece and, to our knowledge, has not been reported elsewhere.
Resumo:
In this work we present an agent-based model for the spread of tuberculosis where the individuals can be infected with either drug-susceptible or drug-resistant strains and can also receive a treatment. The dynamics of the model and the role of each one of the parameters are explained. The whole set of parameters is explored to check their importance in the numerical simulation results. The model captures the beneficial impact of the adequate treatment on the prevalence of tuberculosis. Nevertheless, depending on the treatment parameters range, it also captures the emergence of drug resistance. Drug resistance emergence is particularly likely to occur for parameter values corresponding to less efficacious treatment, as usually found in developing countries.
Resumo:
In this thesis, I examine the influences of westernization, the tension between Japanese modernity and tradition, and the stories of Hans Christian Andersen on Ogawa Mimei’s children’s stories. I begin the body of my thesis with a brief historical background of Japan, beginning with the start of the Meiji period in 1868. Within the historical section, I focus on societal and cultural elements and changes that pertain to my thesis. I also include the introduction of Hans Christian Andersen in Japan. I wrap up the historical section by a description of Ogawa’s involvement in the Japanese proletarian literature movement and the rise of the Japanese proletarian children’s literature movement. Then, I launch into an analysis of Ogawa’s works categorized by thematic elements. These elements include westernization, class conflict, nature and civilization, religion and morals, and children and childhood. When relevant, I also compare and contrast Ogawa’s stories with Andersen’s. In the westernization section, I show how some of Ogawa’s stories demonstrate contact between Japan and the West. In the Class Conflict section, I discuss how Ogawa views class through a socialist lens, whereas Andersen does not dispute class distinctions, but encourages his readers to attempt an upward social climb. In the nature and civilization section, I show how Ogawa and Andersen share common opinions on the impact of civilization on nature. In the religion and morals section, I show how Ogawa incorporates religion, including Christianity, into vii his works. Andersen utilizes religion in a more overt manner in order to convey morals to his audience. Both authors address religious topics like the concept of the afterlife. Finally, in children and childhood, I demonstrate how both Ogawa and Andersen treat their child protagonists and use them and their situations to instruct their readers. Through this case study, I show how westernization and the tensions between Japanese modernization and tradition led to the rise of the proletarian children’s literature movement, which is exemplified by Ogawa’s stories. The emergence of the proletarian children’s literature movement is an indication of the establishment of a new concept of childhood in Japan. Writers like Ogawa Mimei attempted to write children’s stories that represented the new Japanese culture that was a result of adapting Western ideals to fit Japanese society. Some of Ogawa’s stories are a direct commentary on his opinion of Japanese interaction with the West. By comparing Ogawa’s and Andersen’s stories, I demonstrate how Ogawa borrows certain Western elements and possibly responds directly to Andersen. Ogawa also addresses some of the same topics as Andersen, yet their reactions are not always the same. What I find in my analysis supports my thesis that Ogawa is able to maintain Japanese tradition while infusing his children’s stories with Western and modern elements. In doing so, he reflects a largely popular social and cultural practice of his time.
Resumo:
The place-specific activity of hippocampal cells provides downstream structures with information regarding an animal's position within an environment and, perhaps, the location of goals within that environment. In rodents, recent research has suggested that distal cues primarily set the orientation of the spatial representation, whereas the boundaries of the behavioral apparatus determine the locations of place activity. The current study was designed to address possible biases in some previous research that may have minimized the likelihood of observing place activity bound to distal cues. Hippocampal single-unit activity was recorded from six freely moving rats as they were trained to perform a tone-initiated place-preference task on an open-field platform. To investigate whether place activity was bound to the room- or platform-based coordinate frame (or both), the platform was translated within the room at an "early" and at a "late" phase of task acquisition (Shift 1 and Shift 2). At both time points, CA1 and CA3 place cells demonstrated room-associated and/or platform-associated activity, or remapped in response to the platform shift. Shift 1 revealed place activity that reflected an interaction between a dominant platform-based (proximal) coordinate frame and a weaker room-based (distal) frame because many CA1 and CA3 place fields shifted to a location intermediate to the two reference frames. Shift 2 resulted in place activity that became more strongly bound to either the platform- or room-based coordinate frame, suggesting the emergence of two independent spatial frames of reference (with many more cells participating in platform-based than in room-based representations).