Replicación de bases de datos en modalidad “maestroesclavo”, caso de estudio: Firebird SQL Server

Los Sistemas de Gestión de Bases de Datos (SGBD) más evolucionados permiten la programación de desencadenadores o disparadores también llamados triggers, procedimientos y funciones en lenguaje PS/SQL o Transact-SQL. En nuestro caso práctico: Firebird/Interbase® (FB) incorpora el lenguaje de programación PL/SQL, el cual permite la programación de desencadenadores (triggers) y procedimientos almacenados (stored procedures). Como parte del código PL/SQL está disponible la instrucción EXECUTE STATEMENT, la cual permite la ejecución de comandos SQL tanto en forma local como remota. Además este motor de base de datos (FB) trabaja con un algoritmo de confirmación de dos pasadas (two-phase commit, 2PC) para este comando, lo cual es suma importancia porque permite el control de las transacciones distribuidas. De esta forma es posible determinar el éxito o fracaso de la ejecución distribuida de la transacción y de esta manera implementar una replicación de tipo homogénea maestro-esclavo basado en desencadenadores (triggers) con una granularidad de replicación a nivel de tablas. El presente trabajo pretende no solo hacer una replicación maestro-esclavo con Firebird, sino el desarrollo de una aplicación que permita a través de una interface automatizar la implementación de la replicación, generando de forma automática el código y las estructuras necesarias para la replicación y también permitir la posible recuperación en caso de fallas o anomalías. Se abren futuras líneas de investigación sobre nuevas funcionalidades a incorporar a la aplicación propuesta para facilitar la implementación de bases de datos distribuidas en Firebird, fortaleciendo esta funcionalidad no disponible en este motor de base de datos. Esta aplicación está desarrollada bajo licencia LGPL.XV Workshop Bases de Datos y Minería de Datos (WBDDM)Red de Universidades con Carreras en Informática (RedUNCI

Impact of Maternal Undernutrition on Hypothalamo-Pituitary-Adrenal Axis and Adipocyte Functions in Male Rat Offspring

Malnutrition induces profound deleterious effects on several metabolic and neuroendocrine functions. In the present study, we examined the impact of maternal food restriction, during gestation and lactation, on the metabolic-neuroendocrine function of their male offspring at 21 and 60 d of age. Well-nourished (WN) and undernourished (UN) pregnant rats were used, during gestation and lactation, until pups were weaned. Twenty-one-day-old WN and UN male pups were studied in basal and postinsulin conditions. Additional groups of weaned (WN and UN) male rats were fed either ad libitum (WN-WN and UN-WN) or in a restricted fashion (WN-UN and UN-UN) until experimentation at age 60 d. Body weights of mothers and their male offspring were monitored. Basal and post-insulin plasma concentrations of several metabolic fuels were evaluated. Our results indicate that 21-d-old UN male rats exhibited (vs their WN counterparts), decreased body weights, similar basal and postinsulin glycemia, similar basal plasma adrenocorticotropic hormone (ACTH) and corticosterone levels but diminished ACTH response to insulin treatment, and basal hypoleptinemia and significant insulin-induced leptin release. Finally, at 60 d of age, long-term UN (WN-UN and UN-UN) rats showed lower plasma (basal and postinsulin) glucose, and basal triglyceride levels than their counterparts (WN-WN and UN-WN). Sixty-day-old rats submitted to either food restriction protocol also showed a reduced hypothalamo-pituitary-adrenalaxis response to insulin-induced hypoglycemia and basal hypoleptinemia, in spite of restoration of normal body weights. These results further indicate a clear metabolic-neuroendocrine dysfunction in male pups of UN mothers, with the abnormality partially present at weaning and deteriorated by adulthood, even after the recovery of normal body weight. Our study strongly supports the importance of the irreversibility of a deleterious allostatic state resulting from fetal and early postnatal undernutrition.Facultad de Ciencias ExactasInstituto Multidisciplinario de Biología Celula

Analysis of angiotensin II- and ACTH-driven mineralocorticoid functions and omental adiposity in a non-genetic, hyperadipose female rat phenotype

The hypothalamic damage induced by neonatal treatment with monosodium l-glutamate (MSG) induces several metabolic abnormalities, resulting in a rat hyperleptinemic–hyperadipose phenotype. This study was conducted to explore the impact of the neonatal MSG treatment, in the adult (120 days old) female rat on: (a) the in vivo and in vitro mineralocorticoid responses to ACTH and angiotensin II (AII); (b) the effect of leptin on ACTH- and AII-stimulated mineralocorticoid secretions by isolated corticoadrenal cells; and (c) abdominal adiposity characteristics. Our data indicate that, compared with age-matched controls, MSG rats displayed: (1) enhanced and reduced mineralocorticoid responses to ACTH and AII treatments, respectively, effects observed in both in vivo and in vitro conditions; (2) adrenal refractoriness to the inhibitory effect of exogenous leptin on ACTH-stimulated aldosterone output by isolated adrenocortical cells; and (3) distorted omental adiposity morphology and function. This study supports that the adult hyperleptinemic MSG female rat is characterized by enhanced ACTH-driven mineralocorticoid function, impaired adrenal leptin sensitivity, and disrupted abdominal adiposity function. MSG rats could counteract undesirable effects of glucocorticoid excess, by developing a reduced AII-driven mineralocorticoid function. Thus, chronic hyperleptinemia could play a protective role against ACTH-mediated allostatic loads in the adrenal leptin resistant, MSG female rat phenotype.Facultad de Ciencias MédicasComisión de Investigaciones Científicas de la provincia de Buenos Aire

Ghrelin activates hypophysiotropic corticotropin-releasing factor neurons independently of the arcuate nucleus

Previous work has established that the hormone ghrelin engages the hypothalamic-pituitary-adrenal neuroendocrine axis via activation of corticotropin-releasing factor (CRF) neurons of the hypothalamic paraventricular nucleus (PVN). The neuronal circuitry that mediates this effect of ghrelin is currently unknown. Here, we show that ghrelin-induced activation of PVN CRF neurons involved inhibition of γ-aminobutyric acid (GABA) inputs, likely via ghrelin binding sites that were localized at GABAergic terminals within the PVN. While ghrelin activated PVN CRF neurons in the presence of neuropeptide Y (NPY) receptor antagonists or in arcuate nucleus (ARC)-ablated mice, it failed to do it so in mice with ghrelin receptor expression limited to ARC agouti gene related protein (AgRP)/NPY neurons. These data support the notion that ghrelin activates PVN CRF neurons via inhibition of local GABAergic tone, in an ARC-independent manner. Furthermore, these data suggest that the neuronal circuits mediating ghrelin's orexigenic action vs. its role as a stress signal are anatomically dissociated.Instituto Multidisciplinario de Biología CelularLaboratorio de Análisis de Imágene

Resource heterogeneity leads to unjust effort distribution in climate change mitigation

Climate change mitigation is a shared global challenge that involves collective action of a set of individuals with different tendencies to cooperation. However, we lack an understanding of the effect of resource inequality when diverse actors interact together towards a common goal. Here, we report the results of a collective-risk dilemma experiment in which groups of individuals were initially given either equal or unequal endowments. We found that the effort distribution was highly inequitable, with participants with fewer resources contributing significantly more to the public goods than the richer −sometimes twice as much. An unsupervised learning algorithm classified the subjects according to their individual behavior, finding the poorest participants within two “generous clusters” and the richest into a “greedy cluster”. Our results suggest that policies would benefit from educating about fairness and reinforcing climate justice actions addressed to vulnerable people instead of focusing on understanding generic or global climate consequences

Resource heterogeneity leads to unjust effort distribution in climate change mitigation

Climate change mitigation is a shared global challenge that involves collective action of a set of individuals with different tendencies to cooperation. However, we lack an understanding of the effect of resource inequality when diverse actors interact together towards a common goal. Here, we report the results of a collective-risk dilemma experiment in which groups of individuals were initially given either equal or unequal endowments. We found that the effort distribution was highly inequitable, with participants with fewer resources contributing significantly more to the public goods than the richer −sometimes twice as much. An unsupervised learning algorithm classified the subjects according to their individual behavior, finding the poorest participants within two 'generous clusters' and the richest into a 'greedy cluster'. Our results suggest that policies would benefit from educating about fairness and reinforcing climate justice actions addressed to vulnerable people instead of focusing on understanding generic or global climate consequences

White rot in heartwood of Melia azedarach (Meliaceae) specimens from urban trees of La Plata (Buenos Aires): causal agent and chemical-anatomical characterization of the attacked wood

Los hongos xilófagos atacan frecuentemente ejemplares del arbolado urbano descomponiendo su madera. Esto afecta negativamente la estabilidad y resistencia al quiebre, poniendo en riesgo a la población y sus bienes. Durante un relevamiento de las pudriciones presentes en el arbolado de la ciudad de La Plata, fueron observados ejemplares de Melia azedarach (Meliaceae) con evidencias de pudrición blanca en duramen expuesto. El objetivo del trabajo fue identificar al hongo responsable de esta pudrición y analizar las alteraciones anatómicas y químicas que causa en el leño. Se examinaron muestras de duramen con evidencias de pudrición blanca en estadios intermedio y avanzado extraídas de fuste y rama, respectivamente. Los aislamientos fúngicos fueron obtenidos de secciones de madera sembradas en agar malta con antibiótico y fungicida. La identificación fue llevada a cabo a partir de las características de las colonias y confirmada mediante técnicas moleculares. Los estudios anatómicos fueron realizados con microscopios estereoscópico, óptico y electrónico de barrido, y los análisis químicos mediante química húmeda y espectroscopía infrarroja transformada de Fourier (FT-IR). Phlebia brevispora (Basidiomycota, Polyporales) fue la única especie xilófaga aislada del material. Las alteraciones anatómicas registradas permitieron diagnosticar pudrición blanca simultánea en fuste y coexistencia de pudrición blanca simultánea y selectiva en rama. Mediante química húmeda fueron determinados incrementos relativos en el tenor de lignina y extraíbles lipofílicos, y disminuciones en el porcentaje de los extraíbles hidrofílicos en las muestras de ambos estadios de degradación (rama y fuste); la disminución del tenor de celulosa sólo fue identificada en rama. El FT-IR reveló el ataque a la celulosa y la lignina. Si bien existe información previa de la presencia P. brevispora en árboles en pie, el presente hallazgo constituye el primer registro para la Argentina, mientras que la interacción P. brevispora - Melia azedarach es reportada por primera vez en esta contribución.The xylophagous fungi frequently attack specimens of urban trees, decomposing their wood. This negatively affects stability and resistance to breakdown, putting the population and their goods at risk. During a survey of the rot present in the trees of La Plata city, specimens of Melia azedarach (Meliaceae) with evidence of white rot in exposed heartwood were observed. The aim of this work was to identify the fungus responsible for this rot and to analyze the anatomical and chemical alterations it causes in the wood. Heartwood samples with evidence of white rot in intermediate and advanced stages attained from stem and branch, respectively, were used. Fungal isolates were obtained from wood sections cultured on malt agar with antibiotic and fungicide. The identification was based on the characteristics of the colonies and confirmed by molecular techniques. Anatomical studies were performed with stereoscopic, optical and scanning electron microscopes and the chemical analysis by using wet chemistry and Fourier transform infrared spectroscopy (FT-IR). Phlebia brevispora (Basidiomycota, Polyporales) was the only xylophagous species isolated from the material. The anatomical alterations recorded allowed the diagnosis of simultaneous white rot in the stem and the coexistence of simultaneous and selective white rot in branch. Through wet chemistry, relative increases in the content of lignin and lipophilic extracts were determined, and decreases in the percentage of hydrophilic extractables in the samples of both degradation stages (branch and stem); the decrease in cellulose content was only identified in branch. FT-IR revealed the attack on cellulose and lignin. Although there is previous information about the presence of P. brevispora in standing trees, the current finding constitutes the first record for Argentina, while the interaction P. brevispora – Melia azedarach is reported for the first time in this contribution.Facultad de Ciencias Agrarias y ForestalesFacultad de Ciencias Naturales y MuseoCentro de Investigaciones en FitopatologíaInstituto de Fisiología Vegeta

Impact of estradiol on parametrial adipose tissue function : Evidence for establishment of a new set point of leptin sensitivity in control of energy metabolism in female rat.

Estradiol has been implicated in the regulation of food intake; however, its effect seems to be exerted in a bimodal fashion. We examined whether a single im injection of estradiol valerate (E2V), lastingly effective, could induce changes in parametrial fat function that further induce a new set point of leptin sensitivity in the female rat. E2V induced severe anorexia and loss of body weight between d 4 and 12 posttreatment. E2V rats recovered normal food intake and departing body weights on wk 2 and 3 posttreatment, respectively; however, they did not reach body weights of control rats. On d 61 posttreatment, we found that unfasting E2V, vs control, rats displayed increased E2 and leptin circulating levels; reduced plasma tumor necrosis factor-alpha(TNF-alpha) concentrations; similar circulating levels of glucose, insulin, and triglyceride; and lower parametrial fat mass containing a higher number of adipocytes that, although normal in size, in vitro released more leptin. Metabolic responses to fasting indicated that unlike control animals, E2V rats did not decrease triglyceride circulating levels, and that both groups decreased plasma glucose, leptin, and insulin, but not TNF-alpha, levels. High glucose load experiments indicated that E2V animals displayed a better insulin sensitivity than control rats; did not significantly increase circulating leptin concentrations as control rats did; and, unlike control, significantly decreased plasma triglyceride levels. Our data strongly support a potent acute anorectic effect of E2 and that, after several weeks, E2 modified parametrial fat function and insulin sensitivity, protecting the organism against future unfavorable metabolic conditions.Instituto Multidisciplinario de Biología Celula

A simple strategy for culturing morphologically-conserved rat hypothalamic tanycytes

Hypothalamic tanycytes are specialized bipolar ependymal cells that line the floor of the third ventricle. Given their strategic location, tanycytes are believed to play several key functions including being a selective barrier and controlling the amount of hypothalamic-derived factors reaching the anterior pituitary. The in vitro culture of these cells has proved to be difficult. Here, we report an improved method for the generation of primary cultures of rat hypothalamic tanycytes. Ependymal cultures were derived from tissue dissected out of the median eminence region of 10-day-old rats and cultured in a chemically defined medium containing DMEM:F12, serum albumin, insulin, transferrin and the antibiotic gentamycin. After 7 days in vitro, -30% of the cultured cells exhibited morphological features of tanycytes as observed by phase contrast or scanning electron microscopy. Tanycyte-like cells were strongly immuno-reactive for vimentin and dopamine-cAMP-regulated phospho-protein (DARPP-32) and weakly immune-reactive for glial fibrillary acidic protein. Tanycyte-like cells displayed a stable negative resting plasma membrane potential and failed to show spiking properties in response to current injections. When exposed to fluorescent beads in the culture medium, tanycyte-like cells exhibited a robust endocytosis. Thus, the present method effectively yields cultures containing tanycyte-like cells that resemble in vivo tanycytes in terms of morphologic features and molecular markers as well as electrical and endocytic activity. To our knowledge, this is the first protocol that allows the culturing of tanycyte-like cells that can be individually identified and that conserve the morphology of tanycytes in then- natural physiological environment.Instituto Multidisciplinario de Biología CelularComisión de Investigaciones Científicas de la provincia de Buenos Aire

Ghrelin treatment induces rapid and delayed increments of food intake : A heuristic model to explain ghrelin's orexigenic effects

Ghrelin is a stomach-derived peptide hormone with salient roles in the regulation of energy balance and metabolism. Notably, ghrelin is recognized as the most powerful known circulating orexigenic hormone. Here, we systematically investigated the effects of ghrelin on energy homeostasis and found that ghrelin primarily induces a biphasic effect on food intake that has indirect consequences on energy expenditure and nutrient partitioning. We also found that ghrelin-induced biphasic effect on food intake requires the integrity of Agouti-related peptide/neuropeptide Y-producing neurons of the hypothalamic arcuate nucleus, which seem to display a long-lasting activation after a single systemic injection of ghrelin. Finally, we found that different autonomic, hormonal and metabolic satiation signals transiently counteract ghrelin-induced food intake. Based on our observations, we propose a heuristic model to describe how the orexigenic effect of ghrelin and the anorectic food intake-induced rebound sculpt a timely constrain feeding response to ghrelin.Instituto Multidisciplinario de Biología Celula