148 research outputs found
Variable strength of forest stand attributes and weather conditions on the questing activity of Ixodes ricinus ticks over years in managed forests
Given the ever-increasing human impact through land use and climate change on the environment, we crucially need to achieve a better understanding of those factors that influence the questing activity of ixodid ticks, a major disease-transmitting vector in temperate forests. We investigated variation in the relative questing nymph densities of Ixodes ricinus in differently managed forest types for three years (2008–2010) in SW Germany by drag sampling. We used a hierarchical Bayesian modeling approach to examine the relative effects of habitat and weather and to consider possible nested structures of habitat and climate forces. The questing activity of nymphs was considerably larger in young forest successional stages of thicket compared with pole wood and timber stages. Questing nymph density increased markedly with milder winter temperatures. Generally, the relative strength of the various environmental forces on questing nymph density differed across years. In particular, winter temperature had a negative effect on tick activity across sites in 2008 in contrast to the overall effect of temperature across years. Our results suggest that forest management practices have important impacts on questing nymph density. Variable weather conditions, however, might override the effects of forest management practices on the fluctuations and dynamics of tick populations and activity over years, in particular, the preceding winter temperatures. Therefore, robust predictions and the detection of possible interactions and nested structures of habitat and climate forces can only be quantified through the collection of long-term data. Such data are particularly important with regard to future scenarios of forest management and climate warming
Mechanical behavior of asphalt mixtures containing silica gels as warm additives
This paper presents the results of a study of some compounds capable of absorbing water into their structure (silica gel), as potential foaming binders. Asphalt mixtures were manufactured at different manufacturing and compaction temperatures, using four different silica gels. Static and dynamic tests were carried out to determine their behavior in asphalt mixtures. The results were compared with those obtained using hot-mix asphalt and warm-mix asphalt manufactured with zeolite. The lab results showed a similar behavior of asphalt mixtures containing either silica gel or zeolite.The research presented herein was sponsored by the Research Office of Universidad de La Frontera (DIUFRO) under the project number DI15-0089
Health care utilization in the elderly Mexican population: Expenditures and determinants
<p>Abstract</p> <p>Background</p> <p>Worldwide population aging has been considered one of the most important demographic phenomena, and is frequently referred as a determinant of health costs and expenditures. These costs are an effect either of the aging process itself (social) or because of the increase that comes with older age (individual).</p> <p>Objective</p> <p>To analyze health expenditures and its determinants in a sample of Mexican population, for three dimensions acute morbidity, ambulatory care and hospitalization focusing on different age groups, particularly the elderly.</p> <p>Methods</p> <p>A secondary analysis of the Mexican National Health and Nutrition Survey (ENSANUT), 2006 was conducted. A descriptive analysis was performed to establish a health profile by socio-demographic characteristics. Logistic regression models were estimated to determine the relation between acute morbidity, ambulatory care, hospitalization and age group; to establish the determinants of hospitalization among the population 60 years and older; and to determine hospitalization expenditures by age.</p> <p>Results</p> <p>Higher proportion of elderly reporting health problems was found. Average expenditures of hospitalization in households were 308.9 am dlls, the highest among the considered age groups. The multivariate analysis showed higher probability of being hospitalized among the elderly, but not for risks for acute morbidity and ambulatory care. Among the elderly, older age, being male or living in a city or in a metro area implied a higher probability of hospitalization during the last year, with chronic diseases playing a key role in hospitalization.</p> <p>Conclusions</p> <p>The conditions associated with age, such as chronic diseases, have higher weight than age itself; therefore, they are responsible for the higher expenditures reported. Conclusions point towards a differentiated use and intensity of health services depending on age. The projected increase in hospitalization and health care needs for this group requires immediate attention.</p
Overexpression of defense response genes in transgenic wheat enhances resistance to Fusarium head blight
Fusarium head blight (FHB) of wheat, caused by Fusarium graminearum and other Fusarium species, is a major disease problem for wheat production worldwide. To combat this problem, large-scale breeding efforts have been established. Although progress has been made through standard breeding approaches, the level of resistance attained is insufficient to withstand epidemic conditions. Genetic engineering provides an alternative approach to enhance the level of resistance. Many defense response genes are induced in wheat during F. graminearum infection and may play a role in reducing FHB. The objectives of this study were (1) to develop transgenic wheat overexpressing the defense response genes α-1-purothionin, thaumatin-like protein 1 (tlp-1), and β-1,3-glucanase; and (2) to test the resultant transgenic wheat lines against F. graminearum infection under greenhouse and field conditions. Using the wheat cultivar Bobwhite, we developed one, two, and four lines carrying the α-1-purothionin, tlp-1, and β-1,3-glucanase transgenes, respectively, that had statistically significant reductions in FHB severity in greenhouse evaluations. We tested these seven transgenic lines under field conditions for percent FHB disease severity, deoxynivalenol (DON) mycotoxin accumulation, and percent visually scabby kernels (VSK). Six of the seven lines differed from the nontransgenic parental Bobwhite line for at least one of the disease traits. A β-1,3-glucanase transgenic line had enhanced resistance, showing lower FHB severity, DON concentration, and percent VSK compared to Bobwhite. Taken together, the results showed that overexpression of defense response genes in wheat could enhance the FHB resistance in both greenhouse and field conditions
Doença de alzheimer: cognição e discurso narrativo com apoio em figuras
Objetivo investigar as características discursivas de pessoas com Doença de Alzheimer (DA) nos estágios moderado e moderado-grave por meio de uma tarefa com apoio em figuras; examinar possíveis falhas na expressão do conhecimento e a relação entre o discurso e a cognição. Métodos trata-se de um estudo com delineamento transversal, quantitativo, utilizando-se da análise de comparação de grupos. A amostra do grupo clínico foi constituída por dezoito participantes com DA (oito sujeitos com declínio cognitivo moderado (GDS 4), e dez com declínio cognitivo moderado-grave (GDS 5); o grupo controle foi composto de dezesseis sujeitos sem distúrbios neurológicos ou psiquiátricos. Todos sujeitos foram pareados quanto ao gênero, língua materna, idade e escolaridade e todos submetidos a avaliações de habilidades cognitivas. A tarefa discursiva consistiu na narrativa baseada em uma sequência de figuras do conto “Chapeuzinho Vermelho”. Resultados os sujeitos com DA apresentaram escores de coerência global mais baixos, bem como mais falhas na expressão de conhecimento do que sujeitos sem DA e suas características discursivas correlacionaram-se com suas habilidades cognitivas. Os grupos GDS 4 e GDS 5 diferiram com relação à coerência local. Conclusão o discurso dos participantes com DA caracteriza-se por falhas de coerência e informatividade que apresentam relações estreitas com seus déficits cognitivos
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