616 research outputs found
Algorithm Diversity for Resilient Systems
Diversity can significantly increase the resilience of systems, by reducing
the prevalence of shared vulnerabilities and making vulnerabilities harder to
exploit. Work on software diversity for security typically creates variants of
a program using low-level code transformations. This paper is the first to
study algorithm diversity for resilience. We first describe how a method based
on high-level invariants and systematic incrementalization can be used to
create algorithm variants. Executing multiple variants in parallel and
comparing their outputs provides greater resilience than executing one variant.
To prevent different parallel schedules from causing variants' behaviors to
diverge, we present a synchronized execution algorithm for DistAlgo, an
extension of Python for high-level, precise, executable specifications of
distributed algorithms. We propose static and dynamic metrics for measuring
diversity. An experimental evaluation of algorithm diversity combined with
implementation-level diversity for several sequential algorithms and
distributed algorithms shows the benefits of algorithm diversity
Cantilever-based electret energy harvesters
Integration of structures and functions allowed reducing electric
consumptions of sensors, actuators and electronic devices. Therefore, it is now
possible to imagine low-consumption devices able to harvest their energy in
their surrounding environment. One way to proceed is to develop converters able
to turn mechanical energy, such as vibrations, into electricity: this paper
focuses on electrostatic converters using electrets. We develop an accurate
analytical model of a simple but efficient cantilever-based electret energy
harvester. Therefore, we prove that with vibrations of 0.1g (~1m/s^{2}), it is
theoretically possible to harvest up to 30\muW per gram of mobile mass. This
power corresponds to the maximum output power of a resonant energy harvester
according to the model of William and Yates. Simulations results are validated
by experimental measurements but the issues of parasitic capacitances get a
large impact. Therefore, we 'only' managed to harvest 10\muW per gram of mobile
mass, but according to our factor of merit, this puts us in the best results of
the state of the art. http://iopscience.iop.org/0964-1726/20/10/105013Comment: This is an author-created, un-copyedited version of an article
accepted for publication in Smart Materials and Structures. IOP Publishing
Ltd is not responsible for any errors or omissions in this version of the
manuscript or any version derived from it. The definitive
publisher-authenticated version is available online at
doi:10.1088/0964-1726/20/10/105013;
http://iopscience.iop.org/0964-1726/20/10/10501
Recurrence of the blue wing enhancements in the high ionization lines of SDSS 1004+4112 A
We present integral field spectroscopic observations of the quadruple-lensed
QSO SDSS 1004+4112 taken with the fiber system INTEGRAL at the William Herschel
Telescope on 2004 January 19. In May 2003 a blueward enhancement in the high
ionization lines of SDSS 1004+4112A was detected and then faded. Our
observations are the first to note a second event of similar characteristics
less than one year after. Although initially attributed to microlensing, the
resemblance among the spectra of both events and the absence of
microlensing-induced changes in the continuum of component A are puzzling. The
lack of a convincing explanation under the microlensing or intrinsic
variability hypotheses makes the observed enhancements particularly relevant,
calling for close monitoring of this object.Comment: 4 pages, 5 figure
Grupos vulnerables: hacia una economía social
La presente propuesta está destinada a generar herramientas, estrategias y guías de acción a los emprendimientos de los movimientos de trabajadores de empresas recuperadas, organizaciones de desocupados, cooperativas de trabajo, etc., que se inscriben en actual categoría de "economía social”. En el ámbito de la UNSL, el proyecto de Extensión “Forjando derechos hacia una economía social“, comenzó a trabajar a través de un diagnóstico realizado por la cátedra de Derecho Social, en el cual surgió la demanda de sectores de la población excluidos del sistema regular de trabajo, que pretenden incluirse a partir de nuevas estrategias y dinámicas en el ámbito socio económico. Se advierten las dificultades de estos grupos (cooperativa de trabajo Servicios Industriales de limpieza, Asociación de choferes de remises, Cooperativa de trabajo Lanín, productora de envases metálicos, Asociación de Artesanos de San Luís) para organizarse y una vez organizados funcionar acorde a sus necesidades. Se ha observado el fracaso de emprendimientos como cooperativas, grupos de autogestión, ONG, etc. Ante la falta de una política estatal territorial de apoyo, estos grupos en situaciones complejas -cuestiones legales, institucionales, sociales, estatutarias, contables, impositivas financieras- demandan conocer sobre el funcionamiento, sistema legal contable e impositivo de dichas instituciones. En este marco, el equipo extensionista compuesto por docentes, alumnos y graduados de tres carreras (abogacía, Licenciaturas en trabajo social y administración), pretendemos relacionar el conocimiento Universitario con la comunidad, a partir de los siguientes ejes, que constituirán al mismo tiempo las líneas de acción de la actividad extensionista: (1) Capacitación Multidisciplinaria de los componentes del proyecto; (2) Interactuación con los grupos sociales contactados y que demanden la extensión; y (3) Generación de una guía operativa, con instrucciones legales, estatutarias, sociales, grupales, contables económicos e impositivos, para Cooperativas Organizaciones No Gubernamentales y Sindicatos en formación. La primera línea de acción se encuentra en ejecución durante el año en curso, y comprende seminarios internos y externos de capacitación sobre: Derechos Sociales, derechos Humanos, Teoría de Grupo, Economía Social, emprendedurismo, sistemas económicos contables y financieros de las ONG y cooperativas. La segunda línea de acción comienza a implementarse a partir del segundo cuatrimestre del 2012 y durante todo el año 2013 comprende recepcionar las inquietudes y demandas de los grupos definidos y con quines se obtuvo el aval para la concreción del presente proyecto. La tercera línea de acción, a partir de la capacitación y de la experiencia recogida genera un sistema de información permanente, mediante la concreción de guías o manuales vía Internet y escrita, a efectos de que las organizaciones pueden acceder y recepcionar procedimientos instrucciones y consejos sobre la dinámica legal, estatutaria, contable e impositiva de las organizaciones comprendidas en el proyecto. El presente proyecto pretende crear a partir del enfoque multidisciplinario, un ligar permanente de consulta de las organizaciones y al mismo tiempo generar en alumnos y docentes experiencias prácticas sobre la realidad de las mismas, lo cual importa un reciclaje de conocimientos y aprendizajes que enriquecerá la viabilidad y sustentabilidad del proyecto, al posibilitar en una etapa posterior la apertura a todas las organizaciones interesadas en atender los temas objeto del proyecto
Update Review and Clinical Presentation in Congenital Insensitivity to Pain and Anhidrosis
Introduction. Congenital insensitivity to pain and anhidrosis (CIPA) or hereditary sensory and autonomic neuropathy type IV is an extremely rare syndrome. Three clinical findings define the syndrome: insensitivity to pain, impossibility to sweat, and mental retardation. This pathology is caused by a genetic mutation in the NTRK1 gene, which encodes a tyrosine receptor (TrkA) for nerve growth factor (NGF). Methods. The consultation of a child female in our center with CIPA and a tibia fracture in pseudoarthrosis encouraged us to carefully review literature and examine the therapeutic possibilities. A thorough review of literature published in Pubmed was done about CIPA and other connected medical issues mentioned in the paper. Conclusions. The therapeutic approach of CIPA remains unclear. The preventive approach remains the only possible treatment of CIPA. We propose two new important concepts in the therapeutic approach for these patients: (1) early surgical treatment for long bone fractures to prevent pseudoarthrosis and to allow early weight bearing, decreasing the risk of further osteopenia, and (2) bisphosphonates to avoid the progression of osteopenia and to reduce the number of consecutive fractures
Ab initio correlation approach to a ferric wheel-like molecular cluster
We present an ab initio study of electronic correlation effects in a
molecular cluster derived from the hexanuclear ferric wheel
[LiFe6(OCH3)12-(dbm)6]PF6. The electronic and magnetic properties of this
cluster have been studied with all-electron Hartree-Fock, full-potential
density functional calculations and multi-reference second-order perturbation
theory. For different levels of correlation, a detailed study of the impact of
the electronic correlation on the exchange parameter was feasible. As the main
result, we found that the influence of the bridge oxygen atoms on the exchange
parameter is less intense than the influence of the apical ligand groups, which
is due to the geometry of the cluster. With respect to the cluster model
approach, the experimental value of the exchange parameter was affirmed.Comment: to be published in EPJ
Serum HER-2 concentration is associated with insulin resistance and decreases after weight loss.
HER2/neu is a member of the epidermal growth factor receptor family
easily detectable in the serum of cancer patients. We aimed to evaluate
circulating HER-2 concentrations in association with insulin resistance in
healthy and obese subjects. METHODS: Insulin sensitivity (minimal model) and
serum HER-2 concentrations were evaluated in a cross sectional study in men
(cohort 1, n = 167) and longitudinally after weight loss in obese subjects
(cohort 2, n = 30). RESULTS: Serum HER-2 concentrations were positively
associated with BMI and waist circumference (both r = 0.18, p = 0.02), post-load
glucose (r = 0.28, p = 0.001) and fasting triglycerides (r = 0.26, p = 0.001);
and negatively associated with insulin sensitivity (r = -0.29, p = 0.002, n =
109). Subjects with type 2 diabetes showed significantly increased soluble serum
HER-2 concentrations. In different multivariate regression models, fasting
triglycerides emerged as the factor that independently contributed to 10-11% of
serum HER-2 variance.Serum HER-2 concentrations correlated significantly with
fasting triglycerides and insulin sensitivity index in subjects from cohort 2.
Weight loss led to a significant decrease of serum HER-2 concentrations. The
change in serum HER-2 concentrations were significantly associated with the
change in percent body fat and fasting triglycerides in young (below the median
age of the cohort) subjects. CONCLUSIONS: Serum HER-2 concentrations might be
implicated in the pathophysiology of insulin resistance and associated
comorbidities
Endothelial damage, inflammation and immunity in chronic kidney disease
Chronic kidney disease (CKD) patients have an accelerated atherosclerosis, increased risk of thrombotic-ischemic complications, and excessive mortality rates when compared with the general population. There is also evidence of an endothelial damage in which the proinflammatory state, the enhanced oxidative stress, or the accumulation of toxins due to their reduced renal clearance in uremia play a role. Further, there is evidence that uremic endothelial cells are both involved in and victims of the activation of the innate immunity. Uremic endothelial cells produce danger associated molecular patterns (DAMPS), which by binding to specific pattern recognition receptors expressed in multiple cells, including endothelial cells, induce the expression of adhesion molecules, the production of proinflammatory cytokines and an enhanced production of reactive oxygen species in endothelial cells, which constitute a link between immunity and inflammation. The connection between endothelial damage, inflammation and defective immunity in uremia will be reviewed here
Multi-Wavelength Monitoring of the Changing-Look AGN NGC 2617 during State Changes
Optical and near-infrared photometry, optical spectroscopy, and soft X-ray and UV monitoring of the changing-look active galactic nucleus NGC 2617 show that it continues to have the appearance of a type-1 Seyfert galaxy. An optical light curve for 2010-2017 indicates that the change of type probably occurred between 2010 October and 2012 February and was not related to the brightening in 2013. In 2016 and 2017 NGC 2617 brightened again to a level of activity close to that in 2013 April. However, in 2017 from the end of the March to end of July 2017 it was in very low level and starting to change back to a Seyfert 1.8. We find variations in all passbands and in both the intensities and profiles of the broad Balmer lines. A new displaced emission peak has appeared in Hβ. X-ray variations are well correlated with UV-optical variability and possibly lead by ̃2-3 d. The K band lags the J band by about 21.5 ± 2.5 d and lags the combined B + J bands by ̃25 d. J lags B by about 3 d. This could be because J-band variability arises predominantly from the outer part of the accretion disc, while K-band variability is dominated by thermal re-emission by dust. We propose that spectral-type changes are a result of increasing central luminosity causing sublimation of the innermost dust in the hollow bi-conical outflow. We briefly discuss various other possible reasons that might explain the dramatic changes in NGC 2617.Fil: Oknyansky, V. L.. Sternberg Astronomical Institute; RusiaFil: Gaskell, C. M.. Department of Astronomy and Astrophysics. University of California. Santa Cruz; Estados UnidosFil: Mikailov, K. M.. Shamakhy Astrophysical Observatory, National Academy of Sciences.
Pirkuli; AzerbaiyánFil: Lipunov, V. M.. Sternberg Astronomical Institute. M.V.Lomonosov Moscow State University ; RusiaFil: Shatsky, N. I.. Sternberg Astronomical Institute. M.V.Lomonosov Moscow State University; RusiaFil: Tsygankov, S. S.. Tuorla Observatory, Department of Physics and Astronomy. University of Turku.; FinlandiaFil: Gorbovskoy, E. S.. Sternberg Astronomical Institute. M.V.Lomonosov Moscow State University; RusiaFil: Tatarnikov, A. M.. Sternberg Astronomical Institute. M.V.Lomonosov Moscow State University; RusiaFil: Metlov, V. G.. Sternberg Astronomical Institute. M.V.Lomonosov Moscow State University; RusiaFil: Malanchev, K. L.. Sternberg Astronomical Institute. M.V.Lomonosov Moscow State University; RusiaFil: Brotherton, M.B.. University of Wyoming; Estados UnidosFil: Kasper, D.. University of Wyoming; Estados UnidosFil: Du, P.. Institute of High Energy Physics. Chinese Academy of Sciences; ChinaFil: Chen, X.. School of Space Science and Physics. Shandong University; ChinaFil: Burlak, M. A.. Sternberg Astronomical Institute. M.V.Lomonosov Moscow State University; RusiaFil: Buckley, D. A. H.. The South African Astronomical Observatory; SudáfricaFil: Rebolo, R.. Instituto de Astrofisica de Canarias; EspañaFil: Serra-Ricart, M.. Instituto de Astrofisica de Canarias; EspañaFil: Podestá, R.. Universidad Nacional de San Juan; ArgentinaFil: Levato, O. H.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio. Universidad Nacional de San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio; Argentin
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