120 research outputs found

    Plasticity within the Auditory Systems of Fishes

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    Fishes inhabit incredibly cacophonous environments and experience functional, morphological, and transcriptional auditory system plasticity in reproductive state-dependent and auditory experiential contexts. In contrast to the comprehensive study of acoustic overexposure and functional reproductive condition-dependent plasticity within the auditory periphery, the mechanisms underlying acoustic experience-mediated central nervous system plasticity in fishes are generally poorly characterized. Recent research has highlighted neurochemical and transcriptional flexibility within the central nervous systems of fishes in response to prolonged exposure to music. However, the contributions of the acoustic characteristics of musical stimulation to central nervous system plasticity remain unclear. To evaluate the contributions of sound stimulus frequency to brain plasticity, I employed a targeted transcriptional analysis of neuroplasticity-associated genes within the brain of zebrafish (Danio rerio) exposed to 100 Hz and 800 Hz continuous pure tones at a sound pressure level of 140 dB (re 1 μPa) for 1-week intervals across a 4-week period. The transcription of genes involved in mediating connective plasticity fluctuated as a function of duration and frequency of sound exposure, while cellular proliferation did not show variation with sound treatment; suggesting prolonged tonal stimulation may facilitate connective plasticity within the zebrafish brain. These results provide evidence of central nervous system plasticity in response to pure tone exposure and implicate sound-induced behaviour and multisensory inputs in the mediation of sound-induced transcriptional flexibility within the zebrafish brain. Collectively, this thesis highlights the complexity of auditory system plasticity and emphasizes the value of investigating acoustic experience-mediated nervous system plasticity beyond the auditory periphery in fishes

    Trading Ahead of Bad News: Evidence From Short-Sales of Stocks and the Options Market

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    Throughout the past ten years, the United States Environmental Protection Agency (EPA) has issued hundreds of enforcement actions in the electric, natural gas, and petroleum industries. The vast majority of these citations have been violations of environmental statutes, notably the Clean Air Act (CAA) and the Clean Water Act (CWA). My research evaluates the timing of informed investors’ actions pertaining to the public release of these EPA announcements. Since informed traders have much more leverage in the options market, there seems likely to be a concentration of abnormal put option activity shortly before the time in which the announcements reach the public. My sample includes energy companies that were cited by the EPA from 2008 to 2014. In particular, I test whether there is a heightened level of abnormal short-sale and options trading activity prior to these announcements. I find moderate evidence of informed trading in the options market, but no such evidence in the equity market

    Diagnóstico pré-natal e evolução perinatal de 38 casos de hérnia diafragmática congênita: 8 anos de experiência de um serviço terciário brasileiro

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    PURPOSE: To evaluate the perinatal results for neonates with congenital diaphragmatic hernia diagnosed prenatally. METHOD: We reviewed data from 38 cases of congenital diaphragmatic hernia diagnosed prenatally from January 1995 to December 2003 in the Fetal Medicine Unit of the Department of Obstetrics and Gynecology, São Paulo University Medical School. The main data analyzed were gestational age at diagnosis, fetal karyotyping, side of diaphragmatic defect, presence of associated structural malformations, hepatic herniation, and severe mediastinal shift. Perinatal outcomes were obtained by reviewing hospital documents or by directly calling the patients' immediate relatives. RESULTS: Mean gestational age at diagnosis was 29 weeks (range, 16-37 weeks).Thirty (79%) cases had a left diaphragmatic defect and 8 (21%) had a right lesion. Associated structural malformations were observed in 21 (55%) cases, in which 12 fetuses had a normal karyotype and 9 had chromosomal abnormalities. Isolated congenital diaphragmatic hernia was confirmed in 17 (45%) cases. The overall perinatal mortality rate was 92%. Rates of fetal deaths, early neonatal deaths, late neonatal deaths, and survival were 42%, 50%, 0%, and 8%, respectively, in cases with associated structural malformations but normal karyotyping; 56%, 44%, 0%, and 0% for cases with chromosomal abnormalities; and, 0%, 76%, 12%, and 12% in cases with isolated congenital diaphragmatic hernia. The neonatal mortality rate was 89% in cases with isolated congenital diaphragmatic hernia. CONCLUSION: Perinatal mortality was very high in prenatally diagnosed cases of congenital diaphragmatic hernia. Earlier perinatal deaths are associated with the presence of other structural defects or chromosomal abnormalities. In cases of isolated congenital diaphragmatic hernia, mortality is related to the presence of herniated liver, right-sided lesion, and major mediastinal shift.OBJETIVO: Avaliar os resultados neonatais dos casos de hérnia diafragmática congênita com diagnóstico pré-natal. PACIENTES E MÉTODOS: De janeiro de 1995 a dezembro de 2003 foram revisados os dados de 38 fetos com hérnia diafragmática diagnosticada durante o período pré-natal na Unidade de Medicina Fetal do Departamento de Obstetrícia e Ginecologia da Faculdade de Medicina da Universidade de São Paulo. Os dados pré-natais analisados foram: idade gestacional no diagnóstico, cariótipo fetal, lado da lesão, presença de malformação estrutural associada, herniação hepática e desvio garve de mediastino. Os dados perinatais foram avaliados consultando os prontuários médicos ou por contato telefônico. RESULTADOS: A idade gestacional média no diagnóstico foi de 29 semanas (16-37). Trinta (79%) casos apresentavam lesão à esquerda e 8 (21%) à direita. Malformações estruturais associadas foram observadas em 21 (55%) casos, dos quais 12 fetos apresentaram cariótipo normal, enquanto 9 exibiram anomalias cromossômicas. Hérnia diafragmática isolada foi identificada em 17 (457%) casos. A taxa de mortalidade geral foi de 92%. A taxa de óbito fetal, neomorto precoce, neomorto tardio e sobrevivente após 28 dias de vida foram respectivamente: (i) para o grupo com malformação estrutural associada e cariótipo normal, de 42%, 50%, 0% e 8%; (ii) para os casos com cromossomopatia, de 56%, 44%, 0% e 0%; (iii) para os casos com lesões isoladas de 0%, 76%, 12% e 12%. Na hérnia diafragmática congênita isolada, a mortalidade neonatal foi de 88%. CONCLUSÃO: Em nosso serviço, a mortalidade perinatal nos casos de hérnia diafragmática diagnosticada durante o pré-natal é muito alta. Óbitos neonatais precoces estão associados com presença de outros defeitos estruturais ou anomalias cromossômicas. Nos casos de HDC isolada, a mortalidade está relacionada à presença de fígado herniado, lado direito da lesão e desvio grave de mediastino

    Uterine Dysfunction in Biglycan and Decorin Deficient Mice Leads to Dystocia during Parturition

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    Cesarean birth rates are rising. Uterine dysfunction, the exact mechanism of which is unknown, is a common indication for Cesarean delivery. Biglycan and decorin are two small leucine-rich proteoglycans expressed in the extracellular matrix of reproductive tissues and muscle. Mice deficient in biglycan display a mild muscular dystrophy, and, along with mice deficient in decorin, are models of Ehlers-Danlos Syndrome, a connective tissue anomaly associated with uterine rupture. As a variant of Ehlers-Danlos Syndrome is caused by a genetic mutation resulting in abnormal biglycan and decorin secretion, we hypothesized that biglycan and decorin play a role in uterine function. Thus, we assessed wild-type, biglycan, decorin and double knockout pregnancies for timing of birth and uterine function. Uteri were harvested at embryonic days 12, 15 and 18. Nonpregnant uterine samples of the same genotypes were assessed for tissue failure rate and spontaneous and oxytocin-induced contractility. We discovered that biglycan/decorin mixed double-knockout dams displayed dystocia, were at increased risk of delayed labor onset, and showed increased tissue failure in a predominantly decorin-dependent manner. In vitro spontaneous uterine contractile amplitude and oxytocin-induced contractile force were decreased in all biglycan and decorin knockout genotypes compared to wild-type. Notably, we found no significant compensation between biglycan and decorin using quantitative real time PCR or immunohistochemistry. We conclude that the biglycan/decorin mixed double knockout mouse is a model of dystocia and delayed labor onset. Moreover, decorin is necessary for uterine function in a dose-dependent manner, while biglycan exhibits partial compensatory mechanisms in vivo. Thus, this model is poised for use as a model for testing novel targets for preventive or therapeutic manipulation of uterine dysfunction

    Afetações psicológicas de crianças e adolescentes expostos ao conflito armado em uma zona rural da Colômbia

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    Determinaram-se as afetações psicológicas de 284 crianças e adolescentes expostos ao conflito armado em uma zona rural colombiana, selecionados mediante uma amostragem aleatória. Os instrumentos aplicados foram: a Lista de checagem de comportamento infantil, a autoavaliação de comportamentos de jovens, a Lista de sintomas pós-traumáticos, a Escala de estratégias de enfrentamento para adolescentes e a Escala de resiliência para escolares. 72% da população apresentou afetações psicológicas: 64.4%, condutas internalizadas, 47%, condutas externalizadas. 32%, problemas somáticos; 56%, se encontrava em risco de estresse pós-traumático, e 93% consumia álcool de forma moderada. A estratégia de enfretamento mais utilizada era deixar que as coisas se resolvessem sozinhas. Foi encontrada uma alta necessidade de atenção em saúde. Ser homem constituiu um fator de risco de depressão, agressão e problemas sociais. Ao mesmo tempo que ter até doze anos e estar cursando uma série escolar baixa, foi para os sintomas somáticos em adolescentes. Os resultados evidenciaram a afetação da saúde mental dos participantes.Se determinaron las afectaciones psicológicas de 284 niños y adolescentes expuestos al conflicto armado en una zona rural colombiana, seleccionados mediante un muestreo aleatorio por afijación proporcional. Los instrumentos aplicados fueron: la Lista de chequeo de comportamiento infantil, el Auto-reporte de comportamientos de jóvenes, la Lista de síntomas postraumáticos, la Escala de estrategias de afrontamiento para adolescentes y la Escala de resiliencia para escolares. El 72% de la población presentó afectaciones psicológicas: el 64.4%, conductas internalizadas, el 47%, conductas externalizadas en rango clínico. El 32%, problemas somáticos; el 56%, se encontraba en riesgo de estrés postraumático, y el 93% consumía alcohol en grado moderado. La estrategia de afrontamiento más utilizada era dejar que las cosas se arreglaran solas. Se encontró una alta necesidad de atención en salud. Ser hombre constituyó un factor de riesgo de depresión, agresión y problemas sociales en los niños. A su vez, tener hasta doce años y estar cursando un grado escolar bajo, lo fue para los síntomas somáticos en adolescentes. Los resultados evidenciaron la afectación en la salud mental de los participantes.Psychological effects were determined in 284 children and adolescents exposed to armed conflict in a rural area of Colombia, selected through random sampling proportional allocation. The instruments applied were: The Child Behavior Checklist, the Youth Behavior Self-report, the Trauma Symptoms Checklist for Children, the Coping Scale for Adolescents and the Resilience Scale for School Children. Findings showed that 72% of the population suffers from psychological problems, 64.4 from internalizing behavior and 47% from externalizing behavior within clinical range. It was also found that 32% had somatic problems, 56% were at risk for PTSD and 93% had moderate alcohol consumption. The most frequently used coping strategy was to leave things get fixed by themselves. There was a high need for health care. Being male constituted a risk factor for depression, aggression and social problems in children. In turn, being up to12 years old and a student of a lower grade were risk factors for somatic symptoms in adolescents. Results clearly revealed the impact on mental health of the population under study
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