Blockade of NK-1 receptors in the lateral commissural nucleus tractus solitarii of awake rats had no effect on the cardiovascular responses to chemoreflex activation

The neurotransmission of the chemoreflex in the nucleus tractus solitarii (NTS), particularly of the sympatho-excitatory component, is not completely understood. There is evidence that substance P may play a role in the neurotransmission of the chemoreflex in the NTS. Microinjection of substance P (50 pmol/50 nl, N = 12, and 5 nmol/50 nl, N = 8) into the commissural NTS of unanesthetized rats produced a significant increase in mean arterial pressure (101 ± 1 vs 108 ± 2 and 107 ± 3 vs 115 ± 4 mmHg, respectively) and no significant changes in heart rate (328 ± 11 vs 347 ± 15 and 332 ± 7 vs 349 ± 13 bpm, respectively) 2 min after microinjection. Previous treatment with WIN, an NK-1 receptor antagonist (2.5 nmol/50 nl), microinjected into the NTS of a specific group of rats, blocked the pressor (11 ± 5 vs 1 ± 2 mmHg) and tachycardic (31 ± 6 vs 4 ± 3 bpm) responses to substance P (50 pmol/50 nl, N = 5) observed 10 min after microinjection. Bilateral microinjection of WIN into the lateral commissural NTS (N = 8) had no significant effect on the pressor (50 ± 4 vs 42 ± 6 mmHg) or bradycardic (-230 ± 16 vs -220 ± 36 bpm) responses to chemoreflex activation with potassium cyanide (iv). These data indicate that the activation of NK-1 receptors by substance P in the NTS produces an increase in baseline mean arterial pressure and heart rate. However, the data obtained with WIN suggest that substance P and NK-1 receptors do not play a major role in the neurotransmission of the chemoreflex in the lateral commissural NTS.

Tonic and reflex cardiovascular autonomic control in trained-female rats

The effects of exercise training on cardiovascular and autonomic functions were investigated in female rats. After an aerobic exercise training period (treadmill: 5 days/week for 8 weeks), conscious female Wistar (2 to 3 months) sedentary (S, N = 7) or trained rats (T, N = 7) were cannulated for direct arterial pressure (AP) recording in the non-ovulatory phases. Vagal (VT) and sympathetic tonus (ST) were evaluated by vagal (atropine) and sympathetic (propranolol) blockade. Baroreflex sensitivity was evaluated by the heart rate responses induced by AP changes. Cardiopulmonary reflex was measured by the bradycardic and hypotensive responses to serotonin. Resting bradycardia was observed in T (332 ± 7 bpm) compared with S animals (357 ± 10 bpm), whereas AP did not differ between groups. T animals exhibited depressed VT and ST (32 ± 7 and 15 ± 4 bpm) compared to S animals (55 ± 5 and 39 ± 10 bpm). The baroreflex and cardiopulmonary bradycardic responses were lower in T (-1.01 ± 0.27 bpm/mmHg and -17 ± 6 bpm) than in the S group (-1.47 ± 0.3 bpm/mmHg and -41 ± 9 bpm). Significant correlations were observed between VT and baroreflex (r = -0.72) and cardiopulmonary (r = -0.76) bradycardic responses. These data show that exercise training in healthy female rats induced resting bradycardia that was probably due to a reduced cardiac ST. Additionally, trained female rats presented attenuated bradycardic responses to baro- and cardiopulmonary receptor stimulation that were associated, at least in part, with exercise training-induced cardiac vagal reduction.

El absentismo escolar en el municipio de Oviedo : un estudio desde la perspectiva de los Servicios Sociales

Conocer la realidad del absentismo escolar en la poblaci??n de EGB del municipio de Oviedo. 22630 alumnos de EGB de 41 centros del municipio de Oviedo. Se estudia a todo menor con 10 faltas de asistencia entre principio de curso y el 31 de enero. Se analiza: tipolog??a, zonificaci??n, n??mero de alumnos y tasa de absentismo de cada dentro; n??mero y motivo de las faltas; edad, sexo, curso, n??mero de cursos repetidos y cambios de centro de cada alumno; perfil socio-familiar; percepci??n del profesorado en cuanto a aspecto del alumno, indicadores de descuido o maltrato, desarrollo del lenguaje, puntualidad y comportamiento; percepci??n del alumno en cuanto a adaptaci??n al centro; percepci??n de la familia en cuanto al centro escolar y al comportamiento del ni??o. Hoja de recogida de datos en el centro escolar. Cuestionario para el maestro y para el menor. Hoja de recogida de datos en visita al domicilio. Escala de apreciaci??n del hogar. Se establecen dos grupos: de control -menores con ausencias justificadas-, y de riesgo -menores con ausencias no suficientemente justificadas-. Se analizan las diferencias significativas entre ambos grupos para cada una de la variables. Se presentaron 413 casos de alumnos con 10 o m??s faltas, de los cuales 215 pertenecen al grupo de control y 190 al de riesgo. En el grupo de control las faltas se deben frecuentemente a problemas de salud y en el de riesgo en muchas ocasiones se deben a motivos socio-familiares. El perfil del alumno absentista del grupo de riesgo con respecto al de control presenta las siguientes caracter??sticas: menor rendimiento, m??s cambios de centro, menor aprecio positivo del contexto del centro y menor autoestima; el profesor observa en ??l un peor aspecto en higiene, aseo y vestimenta, resulta m??s distra??do, ap??tico, desordenado, con un aprendizaje m??s lento y un desarrollo del lenguaje m??s deficiente, menos adaptado, menos pac??fico y de un humor m??s inestable, menos alegre y comunicativo, menos puntual y hay mucho menor contacto entre su familia y el centro; sus familias suelen ser numerosas, con situaci??n de empleo altamente inestable e ingresos escasos. Los resultados de este estudio indican claramente la necesidad de una intervenci??n coordinada de los sistemas educativos y servicios sociales. Desde estos ??ltimos se hace necesario el desarrollo de un plan concreto de actuaci??n ante este problema, al que es necesario dotar de importantes recursos.

Is Group Lending A Good Enforcement Scheme for Achieving High Repayment Rates?: Evidence from Field Experiments in Vietnam

Microfinance institutions employ various kinds of incentive schemes but estimating the effect of each scheme is not easy due to endogeneity bias. We conducted field experiments in Vietnam to capture the role of joint liability, monitoring, cross-reporting, social sanctions, communication and group formation in borrowers’ repayment behavior. We find that joint liability contracts cause serious free-riding problems, inducing strategic default and lowering repayment rates. When group members observe each others’ investment returns, participants are more likely to choose strategic default. Even after introducing a cross-reporting system and/or penalties among borrowers, the default rates and the ratios of participants who chose strategic default under joint liability are still higher than those under individual lending. We also find that joint liability lending often failed to induce mutual insurance among borrowers. Those who had been helped or who had repaid a little in the previous round were more likely to default strategically and repay a little again in the current round and those who paid large amounts were always the same individuals.

Organizational Capability of Local Societies in Rural Development: A Comparative Study of Microfinance Organizations in Thailand and the Philippines

The importance of organizing local people for development work is widely recognized. Both governmental and non-governmental agencies have implemented various projects that have needed and encouraged collective action by people. Often, however, such projects malfunction after the outside agencies retreat from the project site, suggesting that making organizations is not the same as making a system of making organizations. The latter is essential to make rural organizations self-reliant and sustainable. This paper assumes that such a system exists in local societies and focuses on the capacity of local societies for creating and managing organizations for development. It reveals that (1) such capability differs according to the locality, (2) the difference depends on the structure of the organizations that coordinate people's social relations, and (3) the local administrative bodies define, at least partly, the organizational capability of local societies. We compare two rural societies, one in Thailand and the other in the Philippines, which show clear contrasts in both the form of microfinance organizations and the way of making these organizations.

Imperfect Competition and Costly Screening in the Credit Market under Conditions of Asymmetric Information

This article provides an analysis of how banks determine levels of information production when they are in imperfect competition and there is a condition of information asymmetry between borrowers and banks. Specifically, the study concentrates on information production activities of banks in duopoly where they simultaneously determine intensity of pre-loan screening as well as interest rates. The preliminary model of this paper illustrates that due to strategic complementarities between banks, banking competition can result in inferior equilibrium out of multiple equilibria and insufficient information production. Policymakers must take into account the possible adverse effects of competition-enhancing policies on information production activities.