8 resultados para Reciprocal patchiness of resources

em Biblioteca Digital da Produção Intelectual da Universidade de São Paulo


Relevância:

100.00% 100.00%

Publicador:

Resumo:

Mutualisms such as the figfig wasp mutualism are generally exploited by parasites. We demonstrate that amongst nonpollinating fig wasps (NPFWs) parasitic on Ficus citrifolia, a species of Idarnes galls flowers and another species feeds on galls induced by other wasps killing their larvae. The galling wasp inserts its ovipositor through the fig wall into the fig cavity. The ovipositor then follows a sinuous path and is introduced through the stigma and style of the flower. The egg is deposited between the integument and nucellus, in the exact location where the pollinating mutualistic wasp would have laid its egg. Gall induction is a complex process. In contrast, the path followed by the ovipositor of the other species is straightforward: attacking a larva within a developed gall poses different constraints. Shifts in feeding regime have occurred repeatedly in NPFWs. Monitoring traits associated with such repeated evolutionary shifts may help understand underlying functional constraints. (c) 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106, 114122.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The effects of competition on populations of the bean weevil Zabrotes subfasciatus were analyzed during 41 generations under different competition levels. Three competition environments were established by maintaining the number of couples (6) and varying the amount of available host seeds: HC, high (limited availability of host: 1.35 g); IC, intermediate (intermediate availability of host: 6 g); and LC, low competition (abundance of host: 36 g). It was found that the distribution of the eggs laid on grains was different among treatments: in LC, for example, although females showed high fecundity (35.4 +/- 5.6 eggs/female) the number of eggs laid on each grain was small (1.2 +/- 0.4 eggs on each seed), thus avoiding larval competition of their offspring; whereas in HC treatment, females showed low fecundity (27.04 +/- 4.5 eggs/female) but laid many eggs on each grain (15.03 +/- 4.3 eggs). There were no changes in the ability to respond to different amounts of host via oviposition behavior (egg distribution) during 41 generations. However, HC females had more offspring than LC females under HC conditions. This suggests that HC insects evolved toward higher fitness in crowded conditions. In addition, after inverting the competition level, insects behaved independently of the treatment conditions they experienced through generations, thus showing that oviposition behavior is flexible. Taken together, our results show that Z. subfasciatus presents a broad range of behavioral and physiological responses which allows for quick and reversible adjustments to sudden changes in the amount of resources.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

In the process of creation of the Unified Health System (SUS) as a universal policy seeking to ensure comprehensive care, unscheduled assistance in primary healthcare units (UBS) is an unresolved challenge. The scope of this paper is to analyze the viewpoint of health professionals on the role of primary healthcare units in meeting this demand. It is a transversal study of qualitative data obtained through questionnaires and interviews with 106 medical practitioners from 6 emergency medical services and 190 professionals from 30 units. They explained why people seek emergency care for occurrences pertaining to primary care. The content analysis technique with thematic categories was used for data analysis. Lack of resources and problems with primary health unit work processes (50.8%) were the reasons most frequently cited by emergency care physicians to explain this inadequate demand. Only 33.3% of the health unit professionals agreed that these occurrences should be attended in the primary healthcare services. The limited viewpoint of the role of health services on the unscheduled care, particularly among primary care professionals, possibly leads to restrictive practices for access by the population.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This article discusses the difficulties dairy farmers face when they decide to install a new type of production on their units. We intend to discuss the nature of the new competencies the farmers will construct in order to install new production ateliers, and to show the complexity of the means they used, the difficulties they face in this process, and the strategies farmers develop in consonance with the practical knowledge of their profession. The method used was Ergonomic Work Analysis, together with semi-structured interviews, done after sessions of observation and work analysis. The results show that it is possible to apprehend a part of the complexity of the process of constructing competencies among dairy farmers, the diversity of kinds of resources they mobilize, integrate and transfer in this construction process that materializes through their activities in the work context.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

In this work, we study the performance evaluation of resource-aware business process models. We define a new framework that allows the generation of analytical models for performance evaluation from business process models annotated with resource management information. This framework is composed of a new notation that allows the specification of resource management constraints and a method to convert a business process specification and its resource constraints into Stochastic Automata Networks (SANs). We show that the analysis of the generated SAN model provides several performance indices, such as average throughput of the system, average waiting time, average queues size, and utilization rate of resources. Using the BP2SAN tool - our implementation of the proposed framework - and a SAN solver (such as the PEPS tool) we show through a simple use-case how a business specialist with no skills in stochastic modeling can easily obtain performance indices that, in turn, can help to identify bottlenecks on the model, to perform workload characterization, to define the provisioning of resources, and to study other performance related aspects of the business process.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Abstract Background Facilitating the provision of appropriate health care for immigrant and Aboriginal populations in Canada is critical for maximizing health potential and well-being. Numerous reports describe heightened risks of poor maternal and birth outcomes for immigrant and Aboriginal women. Many of these outcomes may relate to food consumption/practices and thus may be obviated through provision of resources which suit the women's ethnocultural preferences. This project aims to understand ethnocultural food and health practices of Aboriginal and immigrant women, and how these intersect with respect to the legacy of Aboriginal colonialism and to the social contexts of cultural adaptation and adjustment of immigrants. The findings will inform the development of visual tools for health promotion by practitioners. Methods/Design This four-phase study employs a case study design allowing for multiple means of data collection and different units of analysis. Phase 1 consists of a scoping review of the literature. Phases 2 and 3 incorporate pictorial representations of food choices (photovoice in Phase 2) with semi-structured photo-elicited interviews (in Phase 3). The findings from Phases 1-3 and consultations with key stakeholders will generate key understandings for Phase 4, the production of culturally appropriate visual tools. For the scoping review, an emerging methodological framework will be utilized in addition to systematic review guidelines. A research librarian will assist with the search strategy and retrieval of literature. For Phases 2 and 3, recruitment of 20-24 women will be facilitated by team member affiliations at perinatal clinics in one of the city's most diverse neighbourhoods. The interviews will reveal culturally normative practices surrounding maternal food choices and consumption, including how women negotiate these practices within their own worldview and experiences. A structured and comprehensive integrated knowledge translation plan has been formulated. Discussion The findings of this study will provide practitioners with an understanding of the cultural differences that affect women's dietary choices during maternity. We expect that the developed resources will be of immediate use within the women's units and will enhance counseling efforts. Wide dissemination of outputs may have a greater long term impact in the primary and secondary prevention of these high risk conditions.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Background In human malaria, the naturally-acquired immune response can result in either the elimination of the parasite or a persistent response mediated by cytokines that leads to immunopathology. The cytokines are responsible for all the symptoms, pathological alterations and the outcome of the infection depends on the reciprocal regulation of the pro and anti-inflammatory cytokines. IL-10 and IFN-gamma are able to mediate this process and their production can be affected by single nucleotide polymorphisms (SNPs) on gene of these cytokines. In this study, the relationship between cytokine IL-10/IFN-gamma levels, parasitaemia, and their gene polymorphisms was examined and the participation of pro-inflammatory and regulatory balance during a natural immune response in Plasmodium vivax-infected individuals was observed. Methods The serum levels of the cytokines IL-4, IL-12, IFN-gamma and IL-10 from 132 patients were evaluated by indirect enzyme-linked immunosorbent assays (ELISA). The polymorphism at position +874 of the IFN-gamma gene was identified by allele-specific polymerase chain reaction (ASO-PCR) method, and the polymorphism at position -1082 of the IL-10 gene was analysed by PCR-RFLP (PCR-Restriction Fragment Length Polymorphism). Results The levels of a pro- (IFN-gamma) and an anti-inflammatory cytokine (IL-10) were significantly higher in P. vivax-infected individuals as compared to healthy controls. The IFN-gamma levels in primoinfected patients were significantly higher than in patients who had suffered only one and more than one previous episode. The mutant alleles of both IFN-gamma and IL-10 genes were more frequent than the wild allele. In the case of the IFNG+874 polymorphism (IFN-gamma) the frequencies of the mutant (A) and wild (T) alleles were 70.13% and 29.87%, respectively. Similar frequencies were recorded in IL-10-1082, with the mutant (A) allele returning a frequency of 70.78%, and the wild (G) allele a frequency of 29.22%. The frequencies of the alleles associated with reduced production of both IFN-gamma and IL-10 were high, but this effect was only observed in the production of IFN-gamma. Conclusions This study has shown evidence of reciprocal regulation of the levels of IL-10 and IFN-gamma cytokines in P. vivax malaria, which is not altered by the presence of polymorphism in the IL-10 gene.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This study explores the instability created by contradictory court decisions related with contract breaches. Forward marketing contracts represent an important source of resources to finance Brazilian agriculture, however a large number of contract breaches were observed during a period of marked increase in soy prices. The study analyzed 161 judicial appeal decisions and a survey was carried with 70 farmers. The results show the difference of judges' interpretation and the existence of second order effects. The effects of court decisions were more requirements of guarantees and the reduction in the number of contracts. Those soybean farmers who did not breach their contracts have also been negatively affected by the strategic reactions of trading and processing companies. The concept of "social function of the contract" introduced in Brazilian civil code led to a higher degree of instability in contracts, raising transaction costs and motivating private economic sanctions.