Parallel Load Balancing on constrained client-server topologies

We study parallel Load Balancing protocols for the client-server distributed model defined as follows. There is a set of n clients and a set of n servers where each client has (at most) a constant number of requests that must be assigned to some server. The client set and the server one are connected to each other via a fixed bipartite graph: the requests of client v can only be sent to the servers in its neighborhood. The goal is to assign every client request so as to minimize the maximum load of the servers. In this setting, efficient parallel protocols are available only for dense topologies. In particular, a simple protocol, named raes, has been recently introduced by Becchetti et al. [1] for regular dense bipartite graphs. They show that this symmetric, non-adaptive protocol achieves constant maximum load with parallel completion time and overall work, w.h.p. Motivated by proximity constraints arising in some client-server systems, we analyze raes over almost-regular bipartite graphs where nodes may have neighborhoods of small size. In detail, we prove that, w.h.p., the raes protocol keeps the same performances as above (in terms of maximum load, completion time, and work complexity, respectively) on any almost-regular bipartite graph with degree. Our analysis significantly departs from that in [1] since it requires to cope with non-trivial stochastic-dependence issues on the random choices of the algorithmic process which are due to the worst-case, sparse topology of the underlying graph

Optical coherence tomography in Alzheimer's disease. A meta-analysis

BACKGROUND: Alzheimer's disease (AD) is a neurodegenerative disorder, which is likely to start as mild cognitive impairment (MCI) several years before the its full-blown clinical manifestation. Optical coherence tomography (OCT) has been used to detect a loss in peripapillary retina nerve fiber layer (RNFL) and a reduction in macular thickness and volume of people affected by MCI or AD. Here, we performed an aggregate meta-analysis combining results from different studies. METHODS AND FINDINGS: Data sources were case-control studies published between January 2001 and August 2014 (identified through PubMed and Google Scholar databases) that examined the RNFL thickness by means of OCT in AD and MCI patients compared with cognitively healthy controls. RESULTS: 11 studies were identified, including 380 patients with AD, 68 with MCI and 293 healthy controls (HC). The studies suggest that the mean RNFL thickness is reduced in MCI (weighted mean differences in μm, WMD = -13.39, 95% CI: -17.34 to -9.45, p = 0.031) and, even more so, in AD (WMD = -15.95, 95% CI: -21.65 to -10.21, p<0.0001) patients compared to HC. RNFL in the 4 quadrants were all significantly thinner in AD superior (superior WMD = -24.0, 95% CI: -34.9 to -13.1, p<0.0001; inferior WMD = -20.8, 95% CI: -32.0 to -9.7, p<0.0001; nasal WMD = -14.7, 95% CI: -23.9 to -5.5, p<0.0001; and temporal WMD = -10.7, 95% CI: -19.9 to -1.4, p<0.0001); the same significant reduction in quadrant RNFL was observed in MCI patients compared with HC (Inferior WMD = -20.22, 95% CI: -30.41 to -10.03, p = 0.0001; nasal WMD = -7.4, 95% CI: -10.08 to -4.7, p = 0.0000; and temporal WMD = -6.88, 95% CI: -12.62 to -1.13, p = 0.01), with the exception of superior quadrant (WMD = -19.45, 95% CI: -40.23 to 1.32, p = 0.06). CONCLUSION: Results from the meta-analysis support the important role of OCT for RNFL analysis in monitoring the progression of AD and in assessing the effectiveness of purported AD treatments

Pobreza, desigualdad social y ciudadanía. Los límites de las políticas sociales en América Latina

Las ponencias reunidas en este volumen reflejan la vivacidad y diversidad de un debate que aún está por darse en América Latina y el Caribe. Las razones de este retardo son fácilmente identificables: se trata de una de las tantas consecuencias negativas que el triunfo del "pensamiento único" ha tenido en esta parte del mundo. Debido a ello, temáticas como las de la pobreza, la desigualdad social y la inequidad fueron interpretadas en clave crudamente economicista y al interior de un campo teórico el de la economía neoclásica y su expresión en la política económica, el así llamado "Consenso de Washington" que impidieron su adecuada comprensión. La proliferación de trabajos inspirados en esta orientación intelectual y política llegó en algunos casos a extremos lindantes con el grotesco. Por ejemplo, proponer políticas altamente focalizadas, destinadas a grupos muy específicamente recortados de la población general, los llamados "targets", haciendo caso omiso del hecho que más de la mitad de la población de nuestro continente se encuentra afectado por la pobreza. Tales políticas pueden ser racionales y efectivas en países del capitalismo desarrollado (¡cosa que aún estaría por verse, de todos modos!) pero constituyen un lamentable consejo para situaciones como las que prevalecen en nuestros países. La famosa "trickle down theory" ha demostrado ser un bello cuento de hadas sin ningún asidero en la realidad. Pensar en que los mecanismos del mercado se harán cargo de atenuar no hablemos de suprimir la pobreza es desconocer la experiencia histórica de los capitalismos desarrollados en donde ésta fue considerablemente reducida gracias a la acción de las políticas gubernamentales. Mal que le pese al "pensamiento único" fue el estado y no el mercado quien hizo posible una sociedad menos injusta en el mundo industrializado. Ignorar tan elemental enseñanza sólo puede ocasionar más sufrimientos para nuestras sociedades.Indice Reconocimientos Prólogo Parte I. Pobreza, Derechos Sociales y Ciudadanía Paulette Dieterlen Derechos, necesidades básicas y obligación institucional Sara Gordon Ciudadanía y derechos sociales: ¿criterios distributivos? Elina Mecle Armiñana Los derechos sociales en la Constitución Argentina y su vinculación con la política y las políticas sociales Miguel Bazdresch Parada Educación y pobreza: una relación conflictiva Parte II. América Latina: Pobreza y Desigualdad Social Alicia Ziccardi Las ciudades y la cuestión social Francisco Verdera Causas del agravamiento de la pobreza en el Perú desde fines de la década de 1980 Alicia Puyana Riqueza petrolera, políticas macroeconómicas y pobreza rural en Colombia Fernando Cortés Acerca de la reforma y la desigualdad económica Vania Salles y Rosa María Rubalcava Hogares pobres con mujeres trabajadoras y percepciones femeninas Parte III. Políticas Sociales y Gobiernos Locales Laura Golbert ¿Hay opciones en el campo de las políticas sociales? El caso del gobierno autónomo de la Ciudad de Buenos Aires Emilio Duhau Política social, pobreza y focalización. Reflexiones en torno al programa de educación, salud y alimentación Carmen Midaglia y Pedro Robert Uruguay: un caso de estrategias mixtas de protección para sectores vulnerables Sergio Ilari La gestión local de la política social. Los casos de Quilmes y Florencio Varela Beatriz Schmukler Asistencia y prevención de la violencia doméstica en Guanajuato Renato Duarte Seca, pobreza e políticas públicas no nordeste do Brasil Judith Villavicencio y Pedro Hernández Santiago Vivienda social y sectores de bajos ingresos en la Ciudad de México: un encuentro imposibl

Decline of large-diameter trees in a bamboo-dominated forest following anthropogenic disturbances in southwestern Amazonia.

Reduction in the aboveground biomass of larger trees is the main consequence of disturbances in open forests dominated by bamboo. Because these trees are of central importance both for ecosystem function and for the economic value of the forest for management, the impact on these trees due to the increase of bamboo abundance following anthropogenic disturbances is both an environmental and a commercial concern.Includes supplementary material

Fluorescein angiography findings in eyes with lamellar macular hole and epiretinal membrane foveoschisis

PURPOSE. The purpose of this paper was to study fluorescein angiography (FA) findings in eyes with lamellar macular hole (LMH), and epiretinal membrane (ERM) foveoschisis. METHODS. In this prospective, observational case series, 46 eyes of patients affected by either LMH or ERM foveoschisis were examined using optical coherence tomography (OCT) and FA. All patients underwent a comprehensive ophthalmological examination and a general workup to exclude uveitis. Main outcome measures were: presence of FA abnormalities, measurements of the areas of vascular leakage, and intensity of pixels in the vitreous. RESULTS. Twenty-four (52.2%) eyes with LMH and 22 (47.8%) with ERM foveoschisis were studied. Overall, FA abnormalities were found in 20 (83.3%) eyes with LMH and 18 (81.8%) with ERM foveoschisis. The median areas of posterior pole and peripheral leakage were 7.52 vs. 1.07 mm2 (P = 0.03) and 21.8 vs. 3.74 mm2 (P = 0.02) in the LMH and ERM foveoschisis group, respectively. Disk hyperfluorescence was found in 8 and 4 eyes and perivascular leak in 10 and 4 eyes with LMH and ERM foveoschisis, respectively. OCT-derived measurements of vitreous intensity did not differ between the two groups, and the investigational workup for uveitis was negative in all patients. CONCLUSIONS. Discrete areas of central and peripheral leakage are commonly found in eyes with LMH and ERM foveoschisis, whereas perivascular leak and hyperfluorescence of the disc are less frequently observed. These findings suggest that breakdown of the retinal blood barrier, involving the posterior pole and the periphery, is frequently associated with these two vitreoretinal disorders