584 research outputs found
Local and regional heterogeneity underlying hippocampal modulation of cognition and mood.
While the hippocampus has been classically studied for its role in learning and memory, there is significant support for a role of the HPC in regulating emotional behavior. Emerging research suggests these functions may be segregated along the dorsoventral axis of the HPC. In addition to this regional heterogeneity, within the HPC, the dentate gyrus is one of two areas in the adult brain where stem cells continuously give rise to new neurons. This process can influence and be modulated by the emotional state of the animal, suggesting that adult neurogenesis within the DG may contribute to psychiatric disorders and cognitive abilities. Yet, the exact mechanism by which these newborn neurons influence behavior remains unknown. Here, we will examine the contribution of hippocampal neurogenesis to the output of the HPC, and suggest that the role of neurogenesis may vary along the DV axis. Next, we will review literature indicating that anatomical connectivity varies along the DV axis of the HPC, and that this underlies the functional segregation along this axis. This analysis will allow us to synthesize novel hypotheses for the differential contribution of the HPC to cognition and mood
3D Chocolate Printer Dropper
The Mechanical Engineering Department at Washington University in St. Louis is working to stimulate interest in the fields of fluid dynamics and thermal sciences, as students are not typically exposed to these topics within the first two years of school. Dr. Okamoto, Jeff Krampf, and Dr. Weisensee of the Mechanical Engineering Department would like to remedy this situation by developing a laboratory experiment for first year students that utilizes a 3D chocolate printer to teach thermal-fluid concepts in a fun and engaging manner. The goal of this project is to build a chocolate droplet dispensing system, which is a part of the 3D chocolate printing machine. The device must be able to melt chocolate and generate droplets in consistent and adjustable time intervals. The dispensing height of the nozzle should be manually changeable so that the students can understand how height and frequency influence the droplet impact. While the primary function of this device is to help students learn thermal-fluids in a fun yet educational environment, it is also imperative that the device is safe for students to use
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The Role of the Ventral Hippocampus in Anxiety-Related Behavior
The hippocampus is traditionally thought to transmit contextual information to limbic structures where it acquires valence. Using freely moving calcium imaging and optogenetics, we show that while the dorsal CA1 subregion of the hippocampus is enriched in place cells, ventral CA1 (vCA1) is enriched in anxiety cells that are both activated by anxiogenic environments and required for avoidance behavior. Imaging cells defined by their projection target revealed that anxiety cells were enriched in the vCA1 population projecting to the lateral hypothalamic area (LHA), but not to the basal amygdala (BA). Consistent with this selectivity, optogenetic activation of vCA1 terminals in LHA, but not BA increased anxiety and avoidance, while activation of terminals in BA, but not LHA impaired contextual fear memory. Thus, the hippocampus encodes not only neutral but also valence-related contextual information, and the vCA1-LHA pathway is a direct route by which the hippocampus can influence innate anxiety behavior
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SOCIAL WORKERS\u27 PERCEPTION ON THE NEEDS AND SERVICES FOR FOSTER CHILDREN WITH SPECIAL NEEDS
Foster children are already at a disadvantage given that they tend to live in a home without their parents. Social workers have direct interactions working with children with special needs, and through interviews with the workers, we aimed to understand whether or not the services available are able to meet foster children’s special needs. The research on special needs children in foster care is quite limited. The purpose of the study was to identify social workers’ perceptions of the needs of special needs foster children and their access to services.
This study used qualitative interviews with open-ended questions to gather qualitative data from ten social worker participants. The researchers employed thematic analysis techniques to analyze the qualitative data. The themes that emerged from analyzing the data were social workers’ challenges in providing services to special needs foster children, social workers’ access to services, and the need for institutional support to effectively manage service delivery for special needs foster children. This study found that social workers face challenges in obtaining training for parents and social workers, navigating complex funding processes, managing inconsistent desires between parents and court officials, and dealing with the limited number of capable foster homes. The social workers interviewed identified different tactics that could be implemented in order to improve services for the special needs foster children through changes and improvements within the department. Understanding large-scale policy and practice issues, such as organizational change or resource management, can lead county agency social workers to advocate for the challenges of special needs children in child welfare
Guerrerostrongylus marginalis n. sp. (Trichostrongyloidea: Heligmonellidae) from the Guianan arboreal mouse (Oecomys auyantepui) from French Guiana
Based on the number and arrangement of cuticular ridges and configuration of the dorsal ray, nematode specimens collected from the small intestine of eight Guianan arboreal mice, Oecomys auyantepui (Rodentia: Sigmodontinae), in French Guiana are herein described and characterized. Guerrerostrongylus marginalis n. sp. (Heligmosomoidea: Heligmonellidae) shows a synlophe consisting of more than 40 ridges and a unique bursal arrangement with ray 8 (externo-dorsal) extending to the edge of the bursal margin, and appearing more prominent than the dorsal ray. This bursal arrangement is common in members of Hassalstrongylus Durette-Desset, 1971, but uncommon in the other four species in Guerrerostrongylus Sutton & Durette-Desset, 1991. The placement of the new species in Guerrerostrongylus is based on the number and nature of cuticular ridges and the ray arrangement and symmetry of the caudal bursa. Diagnostic characteristics of Guerrerostrongylus marginalis n. sp. include the length of ray 8 relative to bursal margin, the relative size of the spicules and vestibule, and the number of eggs in the uterus. We propose an amendment to the generic diagnosis of Guerrerostrongylus to modify the characters of the long rays 6 (postero-lateral), rays 8 (externo-dorsal), and dorsal ray as diagnostic, since at least ray 6 appears to be short in two different species in the genus, namely G. ulysi Digiani, Notarnicola & Navone, 2012 and G. marginalis n. sp
Age and developmental pyrethroid exposure influence transcriptional and behavioral phenotypes in a Chd8 haploinsufficient autism mouse model
Autism spectrum disorder (ASD) is characterized by early onset communication deficits and restricted, repetitive behavioral patterns. The cause of ASD is complex and likely involves the interplay of multiple genetic variants and environmental influences that trigger physiological changes in genetically-sensitive individuals. In this dissertation, we investigate how genetic and chemical targeting of two biological pathways associated with ASD may exacerbate ASD-associated phenotypes in mice. We affect chromatin modification by generating a mouse strain with a mutation in chromodomain helicase DNA-binding protein 8 (Chd8), a high-confidence gene linked to ASD risk, and target synaptic activity through concurrent exposure to the pesticide, deltamethrin (DM), from conception to postnatal day 22. We report that unexposed Chd8 mutant mice (Chd8V986*/+) display macrocephaly at birth and ASD-associated behavioral phenotypes that become more prominent with age, including anxiety-like behavior, and altered sociability. Analysis of transcriptomic data reveals a core set of genes that is altered in Chd8V986*/+ mice, including Usp11, Wars2, Crlf2, and Eglf6, and published proximity ligation data indicates direct binding of CHD8 to the 5’ region of these genes. Moreover, pathway analysis of Chd8V986*/+ mice suggests reduced neuronal activity embryonically, increased DNA damage repair postnatally, and reduced endoplasmic reticulum stress and unfolded protein response in adults. Further, oligodendrocyte and neurodegenerative transcriptional phenotypes become apparent in the aged mutant mice. Following DM exposure, the mutant mice display an exacerbated phenotype in the elevated plus maze, and a downregulation of genes associated with cellular adhesion in the cerebral cortex of older Chd8V986*/+animals. Finally, we emphasize the importance of controlling for “litter effects” in neurodevelopmental disorder studies. We show that litter effects accounts for 30-60% of the variability associated with commonly studied phenotypes, including brain, placenta, and body weight. Thus, failure to control for litter-to-litter variation can mask phenotypes in ASD mouse models. Our study highlights the importance of incorporating age, controlling for the litter effect, and investigating gene x environment interactions in ASD animal models to expand our understanding of disease etiology.Doctor of Philosoph
La adquisición de prendas de vestir de contrabando y su contingencia tributaria en las pequeñas empresas comerciales de la provincia de Chiclayo, 2017
En la investigación realizada se determinó que era relevante y conveniente investigar el nivel de contingencia tributaria de los pequeños comerciantes a través de la adquisición de prendas de vestir de contrabando. La investigación se enfocó en los comerciantes de distintas galerías ubicadas a exteriores del mercado Modelo del Distrito de Chiclayo, donde se comercializa de manera diaria importantes volúmenes de compra y venta de todo tipo de prendas de vestir; por lo general, sin ningún comprobante de pago que sustente dicha transacción. La informalidad de los comerciantes influye significativamente en la recaudación tributaria generando un impacto negativo en la economía peruana. La presente Tesis tiene como objetivo principal determinar las contingencias tributarias que genera la adquisición de prendas de vestir de contrabando por las pequeñas empresas comerciales en Chiclayo durante el periodo 2017 y hacer de su conocimiento las sanciones de la Administración Tributaria por adquirirlas de contrabando. Durante la realización de la tesis se utilizó técnicas de investigación como la encuesta y el análisis documental y analizar sistemática y estructuradamente la información necesaria concerniente al delito de contrabando del periodo 2017. Finalmente, este estudio tendrá un impacto social al proporcionar una mayor información a las organizaciones del sector comercial de la provincia de Chiclayo las consecuencias que se dan por infringir en el delito de contrabando
Controls on sensible heat and latent energy fluxes from a short-hydroperiod Florida Everglades marsh
Little is known of energy balance in low latitude wetlands where there is a year-round growing season and a climate best defined by wet and dry seasons. The Florida Everglades is a highly managed and extensive subtropical wetland that exerts a substantial influence on the hydrology and climate of the south Florida region. However, the effects of seasonality and active water management on energy balance in the Everglades ecosystem are poorly understood. An eddy covariance and micrometeorological tower was established in a short-hydroperiod Everglades marsh to examine the dominant environmental controls on sensible heat (H) and latent energy (LE) fluxes, as well as the effects of seasonality on these parameters. Seasonality differentially affected H and LE fluxes in this marsh, such that H was principally dominant in the dry season and LE was strongly dominant in the wet season. The Bowen ratio was high for much of the dry season (1.5–2.4), but relatively low (H and LE fluxes across nearly all seasons and years (). However, the 2009 dry season LE data were not consistent with this relationship () because of low seasonal variation in LE following a prolonged end to the previous wet season. In addition to net radiation, H and LE fluxes were significantly related to soil volumetric water content (VWC), water depth, air temperature, and occasionally vapor pressure deficit. Given that VWC and water depth were determined in part by water management decisions, it is clear that human actions have the ability to influence the mode of energy dissipation from this ecosystem. Impending modifications to water management under the Comprehensive Everglades Restoration Plan may shift the dominant turbulent flux from this ecosystem further toward LE, and this change will likely affect local hydrology and climate
Seasonal differences in the CO2 exchange of a short-hydroperiod Florida Everglades marsh
Although wetlands are among the world\u27s most productive ecosystems, little is known of long-term CO2 exchange in tropical and subtropical wetlands. The Everglades is a highly managed wetlands complex occupying \u3e6000 km2 in south Florida. This ecosystem is oligotrophic, but extremely high rates of productivity have been previously reported. To evaluate CO2 exchange and its response to seasonality (dry vs. wet season) in the Everglades, an eddy covariance tower was established in a short-hydroperiod marl marsh. Rates of net ecosystem exchange and ecosystem respiration were small year-round and declined in the wet season relative to the dry season. Inundation reduced macrophyte CO2 uptake, substantially limiting gross ecosystem production. While light and air temperature exerted the primary controls on net ecosystem exchange and ecosystem respiration in the dry season, inundation weakened these relationships. The ecosystem shifted from a CO2 sink in the dry season to a CO2 source in the wet season; however, the marsh was a small carbon sink on an annual basis. Net ecosystem production, ecosystem respiration, and gross ecosystem production were −49.9, 446.1 and 496.0 g C m−2 year−1, respectively. Unexpectedly low CO2 flux rates and annual production distinguish the Everglades from many other wetlands. Nonetheless, impending changes in water management are likely to alter the CO2 balance of this wetland and may increase the source strength of these extensive short-hydroperiod wetlands
El Control Interno En La Gestión Administrativa Del Área De Tesorería De La Municipalidad Distrital Ciudad De Eten-2018
La investigación titulada El control interno en Gestión Administrativa del área de
Tesorería de la MDCE-2018, tuvo como objetivo implementar el control interno
para mejorar la gestión administrativa del área de recaudación del concejo
Distrital de Ciudad Eten – 2018. Se utilizó un diseño de investigación descriptivo
propositivo, permitiendo conocer la realidad del área de recaudación de la
Municipalidad. La población y muestra de objeto de estudio, a los quince
trabajadores vinculado directamente con el manejo y control de efectivo, entre
ellos: contador, gerente general, cajera, tesorera, administración y Finanzas,
Planificación y Presupuesto, y otros del área administrativa, a quienes se les
aplico la guía de observación y el cuestionario. Se concluye; que la
implementación del control interno en los procesos de caja, procesos de cheques,
efectivo, valores y proceso de compra del área de Tesorería de la MDCE-2018;
mejoró la gestión administrativa relacionada con la exactitud y control del saldo de
caja; seguridad razonable, control y custodia de cheques, efectivo y valores.
Asimismo, control y cumplimiento de requisitos para los procesos de adquisición
de bienes y servicios. Se recomendó; que la identificación y valoración de los
riesgos es un propósito del control interno; la detección oportuna de los riesgos
permitirá garantizar efectividad en las operaciones de tesorería, que la
información sea fluida y confiable y que se cumpla las normas técnicas para el
área de Tesorería del Sector Público
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