203 research outputs found

    A Study of Sexual Behavior, Sex Information and Self-Concept in Adolescent Venereal Disease Patients

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    A Research Report Presented to the Faculty of the Raymond A. Kent School of Social Work, University of Louisville, in partial fulfillment of the requirements for the degree of Master of Science in Social Work by Joan Allen, Ralph H. Childers, Hubert Crawford, Olin Gentry, Jr., Ralph Hollon, Carol Hill and Evelyn J. McKissick in June of 1965

    Morphological changes in American kestrels (Falco sparverius) at continental migration sites

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    Many American kestrel (Falco sparverius) populations are declining across North America. Potential causes include mortality from reduction in food availability, a changing climate, habitat degradation, an increase in avian predators, disease, and toxins. We analyzed American kestrel count and banding data from seven raptor migration sites throughout North America with at least 20 years of migration data. We used count data to determine the year at which the kestrel population began a significant decline and then used banding records to determine whether body mass and wing chord declined after this point. We found reductions in kestrel body mass at three sites and reductions in kestrel wing chord at five sites. Our results indicate declines in body size at the majority of sites are consistent with the hypotheses that food availability, impacts of a changing climate, or predation risk may be contributing to population declines

    Surface Modifications by Field Induced Diffusion

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    By applying a voltage pulse to a scanning tunneling microscope tip the surface under the tip will be modified. We have in this paper taken a closer look at the model of electric field induced surface diffusion of adatoms including the van der Waals force as a contribution in formations of a mound on a surface. The dipole moment of an adatom is the sum of the surface induced dipole moment (which is constant) and the dipole moment due to electric field polarisation which depends on the strength and polarity of the electric field. The electric field is analytically modelled by a point charge over an infinite conducting flat surface. From this we calculate the force that cause adatoms to migrate. The calculated force is small for voltage used, typical 1 pN, but due to thermal vibration adatoms are hopping on the surface and even a small net force can be significant in the drift of adatoms. In this way we obtain a novel formula for a polarity dependent threshold voltage for mound formation on the surface for positive tip. Knowing the voltage of the pulse we then can calculate the radius of the formed mound. A threshold electric field for mound formation of about 2 V/nm is calculated. In addition, we found that van der Waals force is of importance for shorter distances and its contribution to the radial force on the adatoms has to be considered for distances smaller than 1.5 nm for commonly used voltages

    Comportamentos agressivos em crianças e adolescentes com risco para esquizofrenia: diferenças entre gêneros

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    OBJECTIVE: This study aimed to investigate whether differences in aggression-related behavioral problems occur between boys and girls at high risk for schizophrenia living in the city of São Paulo, Brazil. METHOD: Using the Child Behavior Checklist, we compared the prevalence of behavioral problems between genders for the offspring (6-18 years) of mothers with diagnosis of schizophrenia and a comparison group of children born to women with no severe mental disorders recruited at the gynecology outpatient clinic of the same hospital. The Structured Clinical Interview for DSM-IV Axis I Disorders, Patient Edition was applied for the evaluation of diagnostic status of mothers. RESULTS: Male children of women with schizophrenia had a lower prevalence of aggressive behavior compared to females (4% vs. 36%; p = 0.005), whereas no gender differences regarding aggression were detected in the comparison group (24% vs. 32%; p = 0.53). Logistic regression analyses showed that male gender and being a child of women with schizophrenia interacted so as to favor lower prevalence of aggressive behavior (p = 0.03). CONCLUSION: These findings reinforce the notion that behavioral gender differences related to schizophrenia are already detectable in childhood.OBJETIVO: Investigar diferenças da ocorrência de comportamentos agressivos entre crianças e adolescentes do sexo masculino e feminino com risco genético para desenvolver esquizofrenia. MÉTODO: A prevalência de comportamentos agressivos foi medida utilizando o inventário de comportamentos para crianças e adolescentes, Child Behavior Checklist, e comparada entre os gêneros para o grupo de crianças filhas de mulheres com esquizofrenia e para um grupo de crianças filhas de mulheres atendidas no serviço de ginecologia do mesmo hospital. A entrevista clínica estruturada para DSM-IV (The Structured Clinical Interview for DSM-IV Axis I Disorders Patient Edition) foi utilizada para confirmar o diagnóstico materno. RESULTADOS: Os filhos de mulheres com esquizofrenia do sexo masculino apresentaram prevalência menor de comportamentos agressivos quando comparados às meninas (4% x 36%; p = 0,005), o que não ocorreu para o grupo comparativo (24% x 32%; p = 0,53). A análise de regressão logística mostrou que pertencer ao sexo masculino e ser filho de mulher com esquizofrenia interagiram de forma a favorecer menor prevalência de comportamentos agressivos (p = 0,03). CONCLUSÃO: Esses achados corroboram para a noção que as diferenças comportamentais entre os gêneros na esquizofrenia podem ser detectadas precocemente durante a infância

    Network Structure of Vertebrate Scavenger Assemblages at the Global Scale: Drivers and Ecosystem Functioning Implications

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    The organization of ecological assemblages has important implications for ecosystem functioning, but little is known about how scavenger communities organize at the global scale. Here, we test four hypotheses on the factors affecting the network structure of terrestrial vertebrate scavenger assemblages and its implications on ecosystem functioning. We expect scavenger assemblages to be more nested (i.e. structured): 1) in species‐rich and productive regions, as nestedness has been linked to high competition for carrion resources, and 2) regions with low human impact, because the most efficient carrion consumers that promote nestedness are large vertebrate scavengers, which are especially sensitive to human persecution. 3) We also expect climatic conditions to affect assemblage structure, because some scavenger assemblages have been shown to be more nested in colder months. Finally, 4) we expect more organized assemblages to be more efficient in the consumption of the resource. We first analyzed the relationship between the nestedness of the scavenger assemblages and climatic variables (i.e. temperature, precipitation, temperature variability and precipitation variability), ecosystem productivity and biomass (i.e. NDVI) and degree of human impact (i.e. human footprint) using 53 study sites in 22 countries across five continents. Then, we related structure (i.e. nestedness) with its function (i.e. carrion consumption rate). We found a more nested structure for scavenger assemblages in regions with higher NDVI values and lower human footprint. Moreover, more organized assemblages were more efficient in the consumption of carrion. However, our results did not support the prediction that the structure of the scavenger assemblages is directly related to climate. Our findings suggest that the nested structure of vertebrate scavenger assemblages affects its functionality and is driven by anthropogenic disturbance and ecosystem productivity worldwide. Disarray of scavenger assemblage structure by anthropogenic disturbance may lead to decreases in functionality of the terrestrial ecosystems via loss of key species and trophic facilitation processes

    Scavenging in the Anthropocene: Human impact drives vertebrate scavenger species richness at a global scale

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    Understanding the distribution of biodiversity across the Earth is one of the most challenging questions in biology. Much research has been directed at explaining the species latitudinal pattern showing that communities are richer in tropical areas; however, despite decades of research, a general consensus has not yet emerged. In addition, global biodiversity patterns are being rapidly altered by human activities. Here, we aim to describe large‐scale patterns of species richness and diversity in terrestrial vertebrate scavenger (carrion‐consuming) assemblages, which provide key ecosystem functions and services. We used a worldwide dataset comprising 43 sites, where vertebrate scavenger assemblages were identified using 2,485 carcasses monitored between 1991 and 2018. First, we evaluated how scavenger richness (number of species) and diversity (Shannon diversity index) varied among seasons (cold vs. warm, wet vs. dry). Then, we studied the potential effects of human impact and a set of macroecological variables related to climatic conditions on the scavenger assemblages. Vertebrate scavenger richness ranged from species‐poor to species rich assemblages (4–30 species). Both scavenger richness and diversity also showed some seasonal variation. However, in general, climatic variables did not drive latitudinal patterns, as scavenger richness and diversity were not affected by temperature or rainfall. Rainfall seasonality slightly increased the number of species in the community, but its effect was weak. Instead, the human impact index included in our study was the main predictor of scavenger richness. Scavenger assemblages in highly human‐impacted areas sustained the smallest number of scavenger species, suggesting human activity may be overriding other macroecological processes in shaping scavenger communities. Our results highlight the effect of human impact at a global scale. As speciesrich assemblages tend to be more functional, we warn about possible reductions in ecosystem functions and the services provided by scavengers in human‐dominated landscapes in the Anthropocene

    Electrical Sintering of Silver Nanoparticle Ink Studied by In-Situ TEM Probing

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    Metallic nanoparticle inks are used for printed electronics, but to reach acceptable conductivity the structures need to be sintered, usually using a furnace. Recently, sintering by direct resistive heating has been demonstrated. For a microscopic understanding of this Joule heating sintering method, we studied the entire process in real time inside a transmission electron microscope equipped with a movable electrical probe. We found an onset of Joule heating induced sintering and coalescence of nanoparticles at power levels of 0.1–10 mW/m3. In addition, a carbonization of the organic shells that stabilize the nanoparticles were found, with a conductivity of 4 105 Sm−1

    Functional biogeography of vertebrate scavengers drives carcass removal across biomes

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    Resumen del trabajo presentado en el XVI Congreso Nacional de la AEET 2023: la ecología en una biosfera humanizada, celebrado en Almería entre el 16 y el 20 de octubre de 2023.Vertebrate scavengers play a crucial role in food web stability and cycling of organic matter and nutrients. However, the global factors that influence their functional biogeography and impact on ecosystem functioning at regional and local levels remain poorly understood. We aim to address this challenge by analyzing a global dataset covering 49 regions in all inhabited continents, including information on 1,847 locally monitored carcasses and 204 vertebrate scavenger species along with their functional traits. We investigate the importance of biogeographical (spatial), environmental and anthropogenic factors in structuring vertebrate scavengers¿ functional trait composition, diversity and abundance. Additionally, we investigate how these biodiversity attributes affect carcass removal at regional and local scales. Our results show that the functional trait composition of assemblages across studied regions was primarily explained by latitude and lon¬gitude, suggesting a strong biogeographical signature. In addition, while functional richness remained unexplained, scavenger abundance responded to both environmental and spatial factors. Further, we found that carcass removal was mainly driven by functional composition, but with the relative importance of particular functional traits varying from local to regional scales. At the local scale, carcass removal was positively related to large carnivorous species with large home ranges, while at the regional scale, carcass removal was better explained by the presence of vultures, other raptors and diurnal birds. Our study provides a better understanding of the factors controlling the func¬tional biogeography of terrestrial vertebrates and their role in maintaining essential ecological functions and services.Peer reviewe

    A Novel Neurotrophic Drug for Cognitive Enhancement and Alzheimer's Disease

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    Currently, the major drug discovery paradigm for neurodegenerative diseases is based upon high affinity ligands for single disease-specific targets. For Alzheimer's disease (AD), the focus is the amyloid beta peptide (Aß) that mediates familial Alzheimer's disease pathology. However, given that age is the greatest risk factor for AD, we explored an alternative drug discovery scheme that is based upon efficacy in multiple cell culture models of age-associated pathologies rather than exclusively amyloid metabolism. Using this approach, we identified an exceptionally potent, orally active, neurotrophic molecule that facilitates memory in normal rodents, and prevents the loss of synaptic proteins and cognitive decline in a transgenic AD mouse model
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