819 resultados para Seasonal Adaptation
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Dissertation presented to obtain the Ph.D degree in Evolutionary Biology
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Dissertation presented to obtain the Ph.D degree in Biochemistry
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Ticks were collected from vegetation and animals at monthly intervals during one year (1993-1994) in an endemic area of Brazilian spotted fever in the County of Pedreira, State of São Paulo. Six species of ticks were identified Amblyomma cajennense, Amblyomma cooperi, Amblyomma triste, Anocentor nitens, Rhipicephalus sanguineus and Boophilus microplus. Only the first species was sufficiently numerous to permit a quantitative study with seasonal activity, although the distribution and source of capture of other species were observed and are reported. This information is correlated with the epidemiology of tick-borne rickettsiosis.
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Dissertação para obtenção do Grau de Mestre em Engenharia Informática
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Between October, 1997 and September, 1999 in Belo Horizonte, Minas Gerais a study of seasonal variation of Lutzomyia longipalpis was carried out in three distinct areas of the municipality. Sand flies were sampled at 15-day intervals in three residences, in each of which two CDC light traps were installed, one indoors and the other in the peridomicile. A total of 397 sand flies were captured in the three areas, with 65%, 30% and 1% of specimens collected in the eastern, northeast and Barreiro districts, respectively. The overall proportions of sand flies collected inside and around the houses were similar (57% vs 43%) and this pattern was seen for both Lutzomyia longipalpis and Lutzomyia whitmani . The highest population levels during the two years of the study were from October to March. From October onwards, numbers increased constantly until February. A gradual fall was seen from April onwards until the lowest levels were reached in the months of June, July and August.
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Complex problems of globalized society challenge its adaptive capacity. However, it is precisely the nature of these human induced problems that provide enough evidence to show that adaptability may not be on a resilient path. This thesis explores the ambiguity of the idea of adaptation (and its practice) and illustrates the ways in which adaptability contributes to resilience of social ecological systems. The thesis combines a case study and grounded theory approach and develops an analytical framework to study adaptability in resource users’ organizations: from what it depends on and what the key challenges are for resource management and system resilience. It does so for the specific case of fish producers’ organizations (POs) in Portugal. The findings suggest that while ecological and market context, including the type of crisis, may influence the character of fishers’ adaptation within POs (i.e. anticipatory, maladaptive and reactively adaptive), it does not determine it. Instead, it makes agency even more crucial (i.e. leadership, trust and agent’s perceptions in terms of their impact on fishers’ motivation to learn from each other). In sum, it was found that internal adaptation can improve POs’ contribution to fishery management and resilience, but it is not a panacea and may, in some cases, increase system vulnerability to change. Continuous maladaptation of some Portuguese POs points at a basic institutional problem (fish market regime), which clearly reduces fisheries resilience as it promotes overfishing. However, structural change may not be sufficient to address other barriers to Portuguese fishers’ (PO members) adaptability, such as history (collective memory) and associated problematic self-perceptions. The agency (people involved in structures and practices) also needs to change. What and how institutional change and agency change build on one another (e.g. comparison of fisheries governance in Portugal and other EU countries) is a topic to be explored in further research.
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Patients with AIDS are particularly susceptible to infection with intestinal coccidia. In this study the prevalence of infections with Cryptosporidium sp and Cystoisospora belli were evaluated among HIV/AIDS patients in the Triângulo Mineiro region, Brazil. Between July 1993 and June 2003 faecal samples from 359 patients were collected and stained by a modified Ziehl-Neelsen method, resulting in 19.7% of positivity for coccidian (8.6% with Cryptosporidium sp, 10.3% with Cystoisospora belli and 0.8% with both coccidian). Patients with diarrhoea and T CD4+ lymphocyte levels < 200 cells/mm3 presented higher frequency of these protozoans, demonstrating the opportunistic profile of these infections and its relationship with the immunological status of the individual. It was not possible to determine the influence of HAART, since only 8.5% of the patients positive for coccidian received this therapy regularly. Parasitism by Cryptosporidium sp was more frequent between December and February and thus was characterised by a seasonal pattern of infection, which was not observed with Cystoisospora belli.
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Organisms that thrive optimally at temperatures above 80°C are called hyperthermophiles. These prokaryotes have been isolated from a variety of hot environments, such as marine geothermal areas, hence they are usually slightly halophilic. Like other halophiles, marine hyperthermophiles have to cope with fluctuations in the salinity of the external medium and generally use low-molecular mass organic compounds to adjust cell turgor pressure. These compounds can accumulate to high levels without interfering with cell metabolism, thereby deserving the designation of compatible solutes. Curiously, the accumulation of compatible solutes also occurs in response to supraoptimal temperatures.(...)
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The species composition of the seasonal várzea forest growing on a bank of the Ilha de Marchantaria / lower Solimões-Amazonas River, Brazil was studied in an area of slightly less than one hectare. Two biomass plots were harvested. Forty-seven arboreal species representing 46 genera in 25 families were recorded. Tree density was 1086 per hectare. Total basal area was 45 m2 ha1. Mean species density was 6.5 ± 1.98 per 100 m2. The most abundant species were Crataeva benthamii(Capparidaceae), Laetia corymbutosa(Flacourtiaceae) and Vitex cymosa(Verbenaceae). The highest basal area per species was 10.2 m2 for Pseudobombax munguba(Bombacaceae). The common species are known to be typical floristic elements of the seasonal varzea forest. Above ground dry biomass was equal to 97 and 255 t ha', respectively. Its chemical composition is characterized by comparatively high bioelement contents equal to 2.4 percent on the average. Calcium was the most important bioelement. Structure of the forest and age darings of trees allow the successional classification of the stands.
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Hematological parameters, intraerythrocytic phosphates, hemoglobin, and whole blood Bohr effect of the South American armored catfish Hoplostenum littorale were studied during different seasons of the year. In addition, the degree of dependence on air breathing was determined for this species. The hematological parameters presented seasonal variations, which were not correlated to oxygen, temperature, and water level oscillations. Five anodic hemoglobin fractions were detected in starch gel electrophoresis. In addition to ATP, GTP and Fe-GTP being detected, 2,3-DPG was also detected in red blood cells of H. littorale. The latter is an intraerythrocytic phosphate characteristic to red blood cells of mammalians. The increased production of 2,3-DPG could be associated with decreasing Hb-O2 affinity and both features could be related to environmental temperature increase. Whole blood Bohr effect was influenced by water temperature. This study confirms H. littorale to be continuous and not obligate air breather, under all dissolved oxygen level conditions.
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In Amazonian floodplains the trees are exposed to extreme flooding of up to 230 days a year. Waterlogging of the roots and stems affects growth and metabolic activity of the trees. An increased leaf fall in the aquatic period and annual increment rings in the wood indicate periodical growth reductions. The present study aims at documenting seasonal changes of metabolism and vitality of adult trees in the annual cycle as expressed by changes of leaf nitrogen content. Leaves of six tree species common in floodplains in Central Amazonia and typical representants of different growth strategies were collected every month between May 1994 and June 1995 in the vicinity of Manaus, Brazil. Mean leaf nitrogen content varied between 1.3% and 3.2% in the non-flooded trees. Three species showed significantly lower Ν content in the flooded period (p=0.05, 0.001, 0.001), the difference ranging 20-25% lower than in the non-flooded period. Two species showed no significant difference while Nectandra amazonum showed 32% more Ν in the flooded season (p=0.001). Leaf nitrogen content was generally high when new leaves were flushed (in the flooded period) and decreased continuously thereafter in all species. Three species showed an additional peak of nitrogen during the first month of the terrestrial phase, in leaves which had flushed earlier, indicating that flooding may disturb nitrogen uptake.
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The observational method in tunnel engineering allows the evaluation in real time of the actual conditions of the ground and to take measures if its behavior deviates considerably from predictions. However, it lacks a consistent and structured methodology to use the monitoring data to adapt the support system in real time. The definition of limit criteria above which adaptation is required are not defined and complex inverse analysis procedures (Rechea et al. 2008, Levasseur et al. 2010, Zentar et al. 2001, Lecampion et al. 2002, Finno and Calvello 2005, Goh 1999, Cui and Pan 2012, Deng et al. 2010, Mathew and Lehane 2013, Sharifzadeh et al. 2012, 2013) may be needed to consistently analyze the problem. In this paper a methodology for the real time adaptation of the support systems during tunneling is presented. In a first step limit criteria for displacements and stresses are proposed. The methodology uses graphics that are constructed during the project stage based on parametric calculations to assist in the process and when these graphics are not available, since it is not possible to predict every possible scenario, inverse analysis calculations are carried out. The methodology is applied to the “Bois de Peu” tunnel which is composed by two tubes with over 500 m long. High uncertainty levels existed concerning the heterogeneity of the soil and consequently in the geomechanical design parameters. The methodology was applied in four sections and the results focus on two of them. It is shown that the methodology has potential to be applied in real cases contributing for a consistent approach of a real time adaptation of the support system and highlight the importance of the existence of good quality and specific monitoring data to improve the inverse analysis procedure.
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Biofilm research is growing more diverse and dependent on high-throughput technologies and the large-scale production of results aggravates data substantiation. In particular, it is often the case that experimental protocols are adapted to meet the needs of a particular laboratory and no statistical validation of the modified method is provided. This paper discusses the impact of intra-laboratory adaptation and non-rigorous documentation of experimental protocols on biofilm data interchange and validation. The case study is a non-standard, but widely used, workflow for Pseudomonas aeruginosa biofilm development, considering three analysis assays: the crystal violet (CV) assay for biomass quantification, the XTT assay for respiratory activity assessment, and the colony forming units (CFU) assay for determination of cell viability. The ruggedness of the protocol was assessed by introducing small changes in the biofilm growth conditions, which simulate minor protocol adaptations and non-rigorous protocol documentation. Results show that even minor variations in the biofilm growth conditions may affect the results considerably, and that the biofilm analysis assays lack repeatability. Intra-laboratory validation of non-standard protocols is found critical to ensure data quality and enable the comparison of results within and among laboratories.
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Objectives: To evaluate neophyte contact lens wearers’ fitting to rigid gas permeable (RGP) contact lenses in terms of wearing time, tear volume, stability, corneal staining, and subjective ratings, over a 1-month period of time. Methods: Twenty-two young healthy subjects were enrolled for wearing RGP on a daily wear basis. The participants included in this study never wore contact lenses and showed a value under 10 in McMonnies Questionnaire. Contact Lens Dry Eye Questionnaire, Visual Analog Scales, Schirmer test, tear film break-up time (BUT), and corneal staining grading were performed. Follow-up visits were scheduled at 1, 7, 15, and 28 days. Results: Six subjects dropped out due to discomfort from the study before 1 month (27% of discontinuation rate). Successful RGP wearers (16 participants) achieved high levels of subjective vision and reported comfort scores of approximately 9 of 10 between 10 and 15 days. They reported wearing their lenses for an average of 10.1262.43 hr after 1 month of wear. Conversely, unsuccessful wearers discontinued wearing the lenses after the first 10 to 15 days, showing comfort scores and wearing time significantly lower compared with the first day of wear. Schirmer test showed a signifi- cant increase at 10 days (P,0.001), and the BUT trends decreased after the first week of wear in unsuccessful group. Conclusions: Symptomatology related with dryness and discomfort, detected during the first 10 days of the adaptation, may help the clinician to predict those participants who will potentially fail to adapt to RGP lens wear.
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Lakes play an important role in biogeochemical, ecological and hydrological processes in the river-floodplain system. The aim of this study was to evaluate the dynamics of the limnological conditions of Catalão Lake, an Amazon floodplain lake. Thus, some of the main limnological environment variables (O2, temperature, pH, nutrient, electrical conductivity) of the Catalão Lake were analyzed under temporal and spacial scales. The study was conducted between November/2004 and August/2005. Sampling excursion were carried out every three months; one excursion for each of the four different hydrological periods (low water, rising water, high water and falling water). Sampling points were chosen so that it could be obtained a gradient of the distance from Negro River. Limnological profiles in Catalão Lake showed generally acidic to slightly alcaline water, with low levels of dissolved oxygen and low concentrations of soluble reactive phosphorous. The Negro River seems to exert the main influence during the rising water period, while the Solimões River is the principal controlling river during peak water. The Principal Component Analysis (PCA) grouped the seasonal collections by hydrological period, showing the formation of a north-south spatial gradient within the lake in relation to the limnological variables. Multivariate dispersion analysis based on distance-to-centroid method demonstrated an increase in similarity over the course of the hydrological cycle, as the lake was inundated in response to the flood pulse of the main river channels. However, the largest spatial homogeneity in the lake was observed in the epilimnion layer, during the falling water period. The daily analysis of variation indicated an oligomitic pattern during the years in which the lake was permanently connected to the Negro River. Although Catalão Lake receives large quantities of both black water from the Negro River and sediment-filled water from the Solimões River, the physical and chemical characteristics of the lake are more similar to those of the Solimões (várzea lake) than the Negro (blackwater lake).