647 research outputs found
Nest site selection and nest survival of Greater Prairie-Chickens near a wind energy facility
Rapid development of wind energy facilities in the Great Plains of North America has raised concerns regarding their potential negative impact on the nesting ecology of Greater Prairie-Chickens (Tympanuchus cupido pinnatus). We investigated the effects of a pre-existing, 36-turbine wind energy facility on nest site selection and nest survival of Greater Prairie-Chickens in the unfragmented grasslands of the Nebraska Sandhills, USA. In 2013 and 2014, we monitored 91 nests along a 24-km disturbance gradient leading away from the wind energy facility. We found little evidence of an effect of the wind energy facility on Greater Prairie-Chicken nest site selection and nest survival. Instead, we found that the primary drivers of nest site selection and nest survival were related to landscape and habitat factors. Greater Prairie-Chickens avoided nesting near roads, with 74% of Greater Prairie-Chickens selecting nest sites .700 m from roads. Greater Prairie-Chickens selected nest sites with more than twice the visual obstruction and residual standing dead vegetation of random points. Our results suggest that small wind energy facilities, such as the facility in our study, may have little effect on Greater Prairie-Chicken nest site selection and nest survival. We suggest that livestock grazing and other grassland management practices still have the most important regional effects on Great Prairie-Chickens, but we caution future planners of wind energy facilities to account for the potential negative effect of roads on nest site selection.
El ra´pido desarrollo de los parque de energ´ıa e´ olica en las Grandes Llanuras de Am´ erica del Norte ha generado preocupaci ´on sobre su potencial impacto negativo en la ecolog´ıa de anidaci ´on de Tympanuchus cupido pinnatus. Investigamos el efecto de un parque de energ´ıa preexistente de 36 turbinas e´ olicas sobre la selecci ´on del sitio de anidaci ´on y la supervivencia del nido de T. c. pinnatus en los pastizales no fragmentados de las Sandhills de Nebraska. En 2013 y 2014, monitoreamos 91 nidos a lo largo de un gradiente de disturbio de 24 km que se alejaba del parque de energ´ıa e´ olica. Encontramos poca evidencia de un efecto del parque de energ´ıa e´ olica sobre la selecci ´on del sitio de anidaci ´on y la supervivencia del nido en T. c. pinnatus. En cambio, encontramos que las causas principales de la selecci ´on del sitio de anidaci ´on y la supervivencia del nido se relacionaron con el paisaje y los factores del ha´bitat. La especie T. c. pinnatus evit ´o anidar cerca de las rutas, con un 74% de los individuos seleccionando sitios de anidaci ´on .700 m desde las rutas. Los individuos seleccionaron sitios de anidaci ´on con ma´s del doble de obstrucci ´on visual y vegetaci ´on residual muerta en pie con relaci ´on a puntos elegidos al azar. Nuestros resultados sugieren que peque˜ nos parques e ´ olicos, como el de nuestro estudio, tendr´ıan un efecto menor en la selecci ´on del sitio de anidaci ´on y en la supervivencia del nido en T. c. pinnatus. Sugerimos que el pastoreo del ganado y otras pra´cticas de manejo de los pastizales se mantienen como los impactos regionales ma´s importantes para T. c. pinnatus, pero alertamos a los futuros gestores de los parques de energ´ıa e´ olica para que contemplen los potenciales efectos negativos de las rutas en la selecci ´on del sitio de anidaci ´ on
Weight Loss Programs May Have Beneficial or Adverse Effects on Fat Mass and Insulin Sensitivity in Overweight and Obese Black Women
OBJECTIVE: Weight loss interventions have produced little change in insulin sensitivity in black women, but mean data may obscure metabolic benefit to some and adverse effects for others. Accordingly, we analyzed insulin sensitivity relative to fat mass change following a weight loss program. DESIGN AND METHODS: Fifty-four black women (BMI range 25.9 to 54.7 kg/m(2)) completed the 6-month program that included nutrition information and worksite exercise facilities. Fat mass was measured by dual-energy X-ray absorptiometry, and insulin sensitivity index (S(I)) was calculated from an insulin-modified intravenous glucose tolerance test using the minimal model. RESULTS: Baseline S(I) (range 0.74 to 7.58 l/mU(−1)•min(−1)) was inversely associated with fat mass (r = −0.516, p < 0.001), independent of age. On average, subjects lost fat mass (baseline 40.8 ± 12.4 to 39.4 ± 12.6 kg [mean ± SD], P < 0.01), but 17 women (32 %) actually gained fat mass. S(I) for the group was unchanged (baseline 3.3 ± 1.7 to 3.2 ± 1.6, P = 0.67). However, the tertile with greatest fat mass loss (−3.6 kg, range −10.7 to −1.7 kg) improved insulin sensitivity (S(I) +0.3 ± 1.2), whereas the tertile with net fat mass gain (+0.9 kg, range −0.1 to +3.8 kg) had reduced insulin sensitivity (S(I) −0.7 ± 1.3) from baseline values (P < 0.05 by ANOVA). CONCLUSIONS: Black women in a weight loss program who lose fat mass may have improved insulin sensitivity, but fat mass gain with diminished sensitivity is common. Additional support for participants who fail to achieve fat mass loss early in an intervention may be required for success
Associations between Potentially Modifiable Risk Factors and Alzheimer Disease: A Mendelian Randomization Study.
BACKGROUND: Potentially modifiable risk factors including obesity, diabetes, hypertension, and smoking are associated with Alzheimer disease (AD) and represent promising targets for intervention. However, the causality of these associations is unclear. We sought to assess the causal nature of these associations using Mendelian randomization (MR). METHODS AND FINDINGS: We used SNPs associated with each risk factor as instrumental variables in MR analyses. We considered type 2 diabetes (T2D, NSNPs = 49), fasting glucose (NSNPs = 36), insulin resistance (NSNPs = 10), body mass index (BMI, NSNPs = 32), total cholesterol (NSNPs = 73), HDL-cholesterol (NSNPs = 71), LDL-cholesterol (NSNPs = 57), triglycerides (NSNPs = 39), systolic blood pressure (SBP, NSNPs = 24), smoking initiation (NSNPs = 1), smoking quantity (NSNPs = 3), university completion (NSNPs = 2), and years of education (NSNPs = 1). We calculated MR estimates of associations between each exposure and AD risk using an inverse-variance weighted approach, with summary statistics of SNP-AD associations from the International Genomics of Alzheimer's Project, comprising a total of 17,008 individuals with AD and 37,154 cognitively normal elderly controls. We found that genetically predicted higher SBP was associated with lower AD risk (odds ratio [OR] per standard deviation [15.4 mm Hg] of SBP [95% CI]: 0.75 [0.62-0.91]; p = 3.4 × 10(-3)). Genetically predicted higher SBP was also associated with a higher probability of taking antihypertensive medication (p = 6.7 × 10(-8)). Genetically predicted smoking quantity was associated with lower AD risk (OR per ten cigarettes per day [95% CI]: 0.67 [0.51-0.89]; p = 6.5 × 10(-3)), although we were unable to stratify by smoking history; genetically predicted smoking initiation was not associated with AD risk (OR = 0.70 [0.37, 1.33]; p = 0.28). We saw no evidence of causal associations between glycemic traits, T2D, BMI, or educational attainment and risk of AD (all p > 0.1). Potential limitations of this study include the small proportion of intermediate trait variance explained by genetic variants and other implicit limitations of MR analyses. CONCLUSIONS: Inherited lifetime exposure to higher SBP is associated with lower AD risk. These findings suggest that higher blood pressure--or some environmental exposure associated with higher blood pressure, such as use of antihypertensive medications--may reduce AD risk.We thank the International Genomics of Alzheimer's Project (IGAP) for providing summary results data for these analyses. The investigators within IGAP contributed to the design and implementation of IGAP and/or provided data but did not participate in analysis or writing of this report. IGAP was made possible by the generous participation of the control subjects, the patients, and their families. The i–Select chips were funded by the French National Foundation on Alzheimer's disease and related disorders. EADI was supported by the LABEX (laboratory of excellence program investment for the future) DISTALZ grant, Inserm, Institut Pasteur de Lille, Université de Lille 2 and the Lille University Hospital. GERAD was supported by the Medical Research Council (Grant n° 503480), Alzheimer's Research UK (Grant n° 503176), the Wellcome Trust (Grant n° 082604/2/07/Z) and German Federal Ministry of Education and Research (BMBF): Competence Network Dementia (CND) grant n° 01GI0102, 01GI0711, 01GI0420. CHARGE was partly supported by the NIH/NIA grant R01 AG033193 and the NIA AG081220 and AGES contract N01–AG–12100, the NHLBI grant R01 HL105756, the Icelandic Heart Association, and the Erasmus Medical Center and Erasmus University. ADGC was supported by the NIH/NIA grants: U01 AG032984, U24 AG021886, U01 AG016976, and the Alzheimer's Association grant ADGC–10–196728.This is the final version of the article. It first appeared from PLOS via http://dx.doi.org/10.1371/journal.pmed.100184
Immune-mediated mechanisms influencing the efficacy of anticancer therapies
Conventional anticancer therapies, such as chemotherapy, radiotherapy, and targeted therapy, are designed to kill cancer cells. However, the efficacy of anticancer therapies is not only determined by their direct effects on cancer cells but also by off-target effects within the host immune system. Cytotoxic treatment regimens elicit several changes in immune-related parameters including the composition, phenotype, and function of immune cells. Here we discuss the impact of innate and adaptive immune cells on the success of anticancer therapy. In this context we examine the opportunities to exploit host immune responses to boost tumor clearing, and highlight the challenges facing the treatment of advanced metastatic disease
The contributions of biodiversity to the sustainable intensification of food production:Thematic Study to support the State of the World’s Biodiversity for Food and Agriculture
Biodiversity supports sustainable food production, although recognition of its roles has been relatively neglected in the sustainable intensification literature. In the current study, the roles of biodiversity in sustainable food production are considered, assessing how these roles can be measured, the current state of knowledge and opportunities for intervention. The trajectory of global food production, and the challenges and opportunities this presents for the roles of biodiversity in production, are also considered, as well as how biodiversitybased interventions fit within wider considerations for sustainable food systems. The positive interactions between a diverse array of organisms, including annual crops, animal pollinators, trees, micro-organisms, livestock and aquatic animals, support food production globally. To support these interactions, a range of interventions related to access to materials and practices are required. For annual crops, major interventions include breeding crops for more positive crop–crop interactions, and the integration of a wider range of crops into production systems. For animal pollinators, major interventions include the introduction of pollinator populations into production landscapes and the protection and improvement of pollinator habitat. For trees, a major required intervention is the greater integration of perennial legumes into farmland. For micro-organisms, the implementation of agronomic practices that support beneficial crop-microbe interactions is crucial. For livestock production, breed and crop feedstock diversification are essential, and the implementation of improved methods for manure incorporation into cropland. Finally, in the case of aquatic production, it is essential to support the wider adoption of multi-trophic production systems and to diversify crop- and animal-based feed resources. These and other interventions, and the research needs around them, are discussed. Looking to the future, understanding the drivers behind trends in food systems is essential for determining the options for biodiversity in supporting sustainable food production. The increased dominance of a narrow selection of foods globally indicates that efforts to more sustainably produce these foods are crucial. From a biodiversity perspective, this means placing a strong emphasis on breeding for resource use efficiency and adaptation to climate change. It also means challenging the dominance of these foods through focusing on productivity improvements for other crop, livestock and aquaculture species, so that they can compete successfully and find space within production systems. New biodiversity-based models that support food production need not only to be productive but to be profitable. Thus, as well as describing appropriate production system management practices that enhance production and support the environment, the labour, knowledge, time required to operationalize, and other costs of new production approaches, must be considered and minimized. To support the future roles of biodiversity in sustainable food production, we recommend that particular attention be given to the longitudinal analysis of food sectors to determine how the diversity of foods consumed from these sectors has changed over time. Analysis is already available for crops, but related research is needed for livestock and aquaculture sectors. This analysis will then support more optimal cross-sectoral interactions, in terms of the contributions each sector provides to supplying the different components of human diets. Additional meta-analyses and synthetic reviews of case studies are required as an evidence base for biodiversity-based food production system interventions, but future studies should pay more attention to articulating the potential biases in case study compilation (the problem of ‘cherry picking’ positive examples) and the measures that have been taken to minimize such effects
Global genetic diversity of Aedes aegypti
Mosquitoes, especially Aedes aegypti, are becoming important models for studying invasion biology. We characterized genetic variation at 12 microsatellite loci in 79 populations of Ae. aegypti from 30 countries in six continents, and used them to infer historical and modern patterns of invasion. Our results support the two subspecies Ae. aegypti formosus and Ae. aegypti aegypti as genetically distinct units. Ae. aegypti aegypti populations outside Africa are derived from ancestral African populations and are monophyletic. The two subspecies co-occur in both East Africa (Kenya) and West Africa (Senegal). In rural/forest settings (Rabai District of Kenya), the two subspecies remain genetically distinct, whereas in urban settings, they introgress freely. Populations outside Africa are highly genetically structured likely due to a combination of recent founder effects, discrete discontinuous habitats and low migration rates. Ancestral populations in sub-Saharan Africa are less genetically structured, as are the populations in Asia. Introduction of Ae. aegypti to the New World coinciding with trans-Atlantic shipping in the 16th to 18th centuries was followed by its introduction to Asia in the late 19th century from the New World or from now extinct populations in the Mediterranean Basin. Aedes mascarensis is a genetically distinct sister species to Ae. aegypti s.l. This study provides a reference database of genetic diversity that can be used to determine the likely origin of new introductions that occur regularly for this invasive species. The genetic uniqueness of many populations and regions has important implications for attempts to control Ae. aegypti, especially for the methods using genetic modification of populations.Centro de Estudios Parasitológicos y de Vectore
Global genetic diversity of Aedes aegypti
Mosquitoes, especially Aedes aegypti, are becoming important models for studying invasion biology. We characterized genetic variation at 12 microsatellite loci in 79 populations of Ae. aegypti from 30 countries in six continents, and used them to infer historical and modern patterns of invasion. Our results support the two subspecies Ae. aegypti formosus and Ae. aegypti aegypti as genetically distinct units. Ae. aegypti aegypti populations outside Africa are derived from ancestral African populations and are monophyletic. The two subspecies co-occur in both East Africa (Kenya) and West Africa (Senegal). In rural/forest settings (Rabai District of Kenya), the two subspecies remain genetically distinct, whereas in urban settings, they introgress freely. Populations outside Africa are highly genetically structured likely due to a combination of recent founder effects, discrete discontinuous habitats and low migration rates. Ancestral populations in sub-Saharan Africa are less genetically structured, as are the populations in Asia. Introduction of Ae. aegypti to the New World coinciding with trans-Atlantic shipping in the 16th to 18th centuries was followed by its introduction to Asia in the late 19th century from the New World or from now extinct populations in the Mediterranean Basin. Aedes mascarensis is a genetically distinct sister species to Ae. aegypti s.l. This study provides a reference database of genetic diversity that can be used to determine the likely origin of new introductions that occur regularly for this invasive species. The genetic uniqueness of many populations and regions has important implications for attempts to control Ae. aegypti, especially for the methods using genetic modification of populations.Centro de Estudios Parasitológicos y de Vectore
HIV-1 Superinfection in Women Broadens and Strengthens the Neutralizing Antibody Response
Identifying naturally-occurring neutralizing antibodies (NAb) that are cross-reactive against all global subtypes of HIV-1 is an important step toward the development of a vaccine. Establishing the host and viral determinants for eliciting such broadly NAbs is also critical for immunogen design. NAb breadth has previously been shown to be positively associated with viral diversity. Therefore, we hypothesized that superinfected individuals develop a broad NAb response as a result of increased antigenic stimulation by two distinct viruses. To test this hypothesis, plasma samples from 12 superinfected women each assigned to three singly infected women were tested against a panel of eight viruses representing four different HIV-1 subtypes at matched time points post-superinfection (∼5 years post-initial infection). Here we show superinfected individuals develop significantly broader NAb responses post-superinfection when compared to singly infected individuals (RR = 1.68, CI: 1.23–2.30, p = 0.001). This was true even after controlling for NAb breadth developed prior to superinfection, contemporaneous CD4+ T cell count and viral load. Similarly, both unadjusted and adjusted analyses showed significantly greater potency in superinfected cases compared to controls. Notably, two superinfected individuals were able to neutralize variants from four different subtypes at plasma dilutions >1∶300, suggesting that their NAbs exhibit elite activity. Cross-subtype breadth was detected within a year of superinfection in both of these individuals, which was within 1.5 years of their initial infection. These data suggest that sequential infections lead to augmentation of the NAb response, a process that may provide insight into potential mechanisms that contribute to the development of antibody breadth. Therefore, a successful vaccination strategy that mimics superinfection may lead to the development of broad NAbs in immunized individuals
Assessing the authority of political office-holders: the leadership capital index
This article argues that the extent to which political office-holders can effectively attain and wield authority is a function of the stock of ‘leadership capital.’ Drawing on the concept of political capital, we define leadership capital as aggregate authority composed of three dimensions: skills; relations; and reputation of a leader. Leadership capital ebbs and flows over time within a trajectory of acquisition, expenditure and inevitable depreciation. We present a Leadership Capital Index (LCI) that systematically maps out the three broad areas combining concrete measures with interpretive aspects. This can be used as a tool for systematically tracking and comparing the political fortunes of leaders in a way that is both more nuanced and robust than exclusive reliance on the latest approval ratings. We offer an illustrative case study of Tony Blair demonstrating the LCI. We conclude by discerning several promising paths for future development of the LCI
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