121 research outputs found
Gravitational Lensing and the Power Spectrum of Dark Matter Substructure: Insights from the ETHOS N-body Simulations
Strong gravitational lensing has been identified as a promising astrophysical
probe to study the particle nature of dark matter. In this paper we present a
detailed study of the power spectrum of the projected mass density
(convergence) field of substructure in a Milky Way-sized halo. This power
spectrum has been suggested as a key observable that can be extracted from
strongly lensed images and yield important clues about the matter distribution
within the lens galaxy. We use two different -body simulations from the
ETHOS framework: one with cold dark matter and another with self-interacting
dark matter and a cutoff in the initial power spectrum. Despite earlier works
that identified kpc as the most promising scales to
learn about the particle nature of dark matter we find that even at lower
wavenumbers - which are actually within reach of observations in the near
future - we can gain important information about dark matter. Comparing the
amplitude and slope of the power spectrum on scales kpc from lenses at different redshifts can help us distinguish between
cold dark matter and other exotic dark matter scenarios that alter the
abundance and central densities of subhalos. Furthermore, by considering the
contribution of different mass bins to the power spectrum we find that subhalos
in the mass range M are on average the largest
contributors to the power spectrum signal on scales kpc, despite the numerous subhalos with masses M in
a typical lens galaxy. Finally, by comparing the power spectra obtained from
the subhalo catalogs to those from the particle data in the simulation
snapshots we find that the seemingly-too-simple halo model is in fact a fairly
good approximation to the much more complex array of substructure in the lens.Comment: 13 pages + appendices, 7 figure
Articulación preescolar-primaria: recomendaciones al maestro
Al incorporarse a la vida escolar, el niño experimenta una reestructuración psicológica esencial, pero este niño que culmina su 6to. año de vida y comienza en el 1er. grado, mantiene aún, las características psicológicas propias de la edad preescolar, requiriendo un tiempo de adaptación a los nuevos cambios en su vida. Algunos maestros de 1er. grado, en su manejo pedagógico con los niños, pretenden convertirlos bruscamente en escolares, obviando que este momento constituye una necesidad y de hecho, un período de tránsito de preescolar a escolar, que ocurre en las condiciones físico-ambientales de una escuela. Por tanto, una problemática actual es la necesidad de la preparación de los docentes del 1er. grado en la utilización de estrategias que favorezcan la continuidad entre la educación preescolar y la escolar. Se trata entonces de orientar al maestro en la instrumentación de su labor pedagógica a fin de evitar que se produzca un cambio brusco de una etapa a otra
Geoquímica del magmatismo mesozoico asociado al margen continental pasivo en el occidente y centro de Cuba
Secuencias estratigráficas de Margen Continental Pasivo (MCP) han sido descritas en la región mesoamericana. En Cuba las mismas están representadas por rocas siliciclásticas y carbonatadas. Litologías de origen magmático (hialoclastita, basalto, diabasa y gabro) y meta-magmático (meta volcánicos, metagabro, anfibolita y eclogita) entre otras, aparecen intercaladas en los cortes sedimentarios. Esta actividad magmática se ha relacionado con la fragmentación de Pangea (en un proceso de tipo rift-drift) y con la etapa inicial de desarrollo de la corteza oceánica del proto-Caribe. A partir de la interpretación de una amplia base de datos petrográficos y geoquímicos (considerando información publicada, así como generada en el presente estudio), se propone un modelo conceptual para explicar el magmatismo del MCP que aflora en la Cordillera Guaniguanico y los terrenos metamórficos de Pinos y Escambray: (a) posiblemente durante el Jurásico Inferior (?) - Jurásico Superior (Oxfordiano Medio/Superior) en un ambiente de Margen Continental, se produjo un magmatismo tipo E-MORB por fusión parcial de una fuente mantélica enriquecida; (b) un volumen importante de magma tipo N-MORB fue generado (producto de una fusión parcial de una fuente mantélica empobrecida) cuando la apertura del océano fue suficiente para que se estableciera una dispersión en estado estacionario, sin la influencia de sistemas de pluma mantélica. Este magmatismo alcanzó su máxima generación en el Oxfordiano Superior - Kimmeridgiano temprano?; (c) cuando se produjo el magma de características N-MORB, es probable que además se alojará (en forma de sills y diques) en las secuencias anteriormente formadas en el estadío syn-rift del margen continental. Por lo que es posible encontrar litologías de este tipo en secuencias más antiguas a dicho evento (e.g., formaciones Loma La Gloria y Arroyo Cangre); y (d) durante el Cretácico Inferior tardío al Cretácico Superior basal se registró un magmatismo de tipo E-MORB (e.g., formaciones Yaguanabo y El Tam- bor), el cual estuvo posiblemente relacionado con una nueva condición de margen vinculado a Caribeana. La mayor parte de las litologías magmáticas y sedimentarias del MCP fueron metamorfizadas en la subducción del Caribe durante el Campaniano Superior tardío y, posteriormente, exhumadas en el periodo Maastrichtiano – Paleoceno temprano
Transcranial Magnetic Stimulation for the Treatment of Cocaine Addiction: A Systematic Review
Cocaine use disorder; Craving; Non-invasive brain stimulationTrastorn per consum de cocaïna; Ànsia; Estimulació cerebral no invasivaTrastorno por consumo de cocaína; Ansia; Estimulación cerebral no invasivaLong-term cocaine use is associated with cognitive deficits and neuro-psychiatric pathologies. Repetitive transcranial magnetic stimulation (rTMS) is an emerging therapeutic strategy relating to changes in brain activity. It stimulates the prefrontal cortex and is involved in inhibitory cognitive control, decision making and care. This systematic review aims to evaluate and synthesize the evidence on the safety, effectiveness, and cost-effectiveness of rTMS for the treatment of cocaine addiction. A systematic review of the literature was carried out. The following electronic databases were consulted from inception to October 2020: MEDLINE, Embase, CINAHL, PsycINFO, Cochrane Central Register of Controlled Trials and Web of Science. Randomised controlled trials, non-randomised controlled trials and case-series and full economic evaluations were included. Twelve studies were included. No identified study reported data on cost-effectiveness. Significant results of the efficacy of TMS have been observed in terms of the reduction of craving to consume and the number of doses consumed. No serious adverse effects have been observed. Despite the low quality of the studies, the first results were observed in terms of reduction of cocaine use and craving. In any case, this effect is considered moderate. Studies with larger sample sizes and longer follow-ups are required
Morph-physiological cellular changes during cardiac-pulmonary-cerebral resuscitation
Cell suffer structural and metabolic changes in stress situations,which allow them to maintain an adequate homeostasis and avoid death . This bibliographic review had the objective of describing the main morph-physiological changes which occur in cardiac failure and cardiac-pulmonary-cerebral resuscitation. The method was documentary reviewing (database Regional SciELO, PubMed, Cochrane and Infomed), developed during the first semester of 2018. Twenty eight references were selected. It was concluded that there are cellular changes during circulatory stop, the procedures of resuscitation and re-perfusion. In cardiac failure, cellular changes are expressed in all the organelles. And may cause death due to necroses. During re-perfusion new structural changes occur, for calcium entrance, sodium disturbances, production of free radicals and swelling. Morph.physiological changes depend on previous metabolic condition, time of cardiac failure and the successful establishment of resuscitation measures
Proposal of the energy potentials in "La Majagua", a rural community to electrify
Para definir la forma en que se electrificará una comunidad rural, la valoración del uso de las fuentes renovables de energía y su impacto, se ha convertido en un aspecto fundamental en las últimas décadas. Esta investigación está basada en el análisis de las potencialidades energéticas que existen en "La Majagua", comunidad rural que no ha sido electrificada, para proponer alternativas energéticas para su electrificación, mediante la aplicación del modelo SURE para la toma de decisiones en proyectos de energización rural. Para esto fue necesario caracterizar la comunidad a partir de una encuesta predeterminada, identificando los criterios de la población sobre el uso de las potencialidades de fuentes energéticas locales, realizar el cálculo de la potencia necesaria estableciendo un módulo de equipos por casa, resultando 4,460 kWh/día de demanda para el módulo 1 con refrigerador, y de 1,26 kWh/día para el módulo 2 sin refrigerador. Del análisis se obtuvieron cuatro propuestas de electrificación: solar fotovoltaica con dos variantes de equipos individuales por vivienda, uno con 8 paneles (módulo 1) y otro con 2 paneles (módulo 2), ambos de 180 W; hidroenergía, con dos turbinas Michell Banki y una energía garantizada de 2,822 GWh/año; y conexión al Sistema Electroenergético Nacional; posibilitando brindar un beneficio a la comunidad, contribuyendo al desarrollo humano y social de sus pobladores
Evaluation of the efficacy and safety of text messages targeting adherence to cardiovascular medications in secondary prevention: the txt2heart Colombia randomised controlled trial protocol.
INTRODUCTION: Anti-platelet therapy, angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers, beta-blockers and statins are cost-effective in patients with atherosclerotic cardiovascular diseases (ASCVD) for reducing the risk of ASCVD events. Unfortunately, there is abundant evidence that adherence to these cardiovascular medications is far from ideal. A recent Cochrane review showed a potential beneficial effect of Short Message Service (SMS) interventions on adherence to medication in ASCVD patients. METHODS AND ANALYSIS: The txt2heart study is a pragmatic randomised single-blind controlled trial. The objective is to evaluate the efficacy and safety of an intervention with SMS messages delivered by mobile phones to improve adherence to cardiovascular medications in patients with ASCVD. The intervention consists of behavioural techniques delivered via SMS. The primary outcome is change in blood serum low-density lipoprotein cholesterol levels as an indicator of adherence to statins. Secondary outcomes will include systolic blood pressure as an indicator of adherence to blood-lowering therapies and heart rate as an indicator of adherence to beta-blockers, urine levels of 11-dehydrothromboxane B2, self-reported adherence to cardiovascular medications and rates of cardiovascular death or hospitalisation due to cardiovascular disease. ETHICS AND DISSEMINATION: The study will be performed in compliance with the protocol, regulatory requirements, Good Clinical Practice and ethical principles of the Declaration of Helsinki. The Ethics Committee of Fundación Cardiovascular de Colombia evaluated and approved the trial. The txt2heart Colombia trial aims to provide robust evidence to evaluate whether SMS messages delivered through mobile telephones change the behaviour of Colombian patients who have suffered a cardiovascular event. Trial results will be presented to the local health authorities, and if the intervention is effective and safe, we hope this strategy will be implemented quickly because of its low cost and wide-reaching impact on the population. TRIAL REGISTRATION NUMBER: NCT03098186
Development and validation of a nomogram to predict kidney survival at baseline in patients with C3 glomerulopathy
Background
C3 glomerulopathy is a rare and heterogeneous complement-driven disease. It is often challenging to accurately predict in clinical practice the individual kidney prognosis at baseline. We herein sought to develop and validate a prognostic nomogram to predict long-term kidney survival.
Methods
We conducted a retrospective, multicenter observational cohort study in 35 nephrology departments belonging to the Spanish Group for the Study of Glomerular Diseases. The dataset was randomly divided into a training group (n = 87) and a validation group (n = 28). The least absolute shrinkage and selection operator (LASSO) regression was used to screen the main predictors of kidney outcome and to build the nomogram. The accuracy of the nomogram was assessed by discrimination and risk calibration in the training and validation sets.
Results
The study group comprised 115 patients, of whom 46 (40%) reached kidney failure in a median follow-up of 49 months (range 24?112). No significant differences were observed in baseline estimated glomerular filtration rate (eGFR), proteinuria or total chronicity score of kidney biopsies, between patients in the training versus those in the validation set. The selected variables by LASSO were eGFR, proteinuria and total chronicity score. Based on a Cox model, a nomogram was developed for the prediction of kidney survival at 1, 2, 5 and 10 years from diagnosis. The C-index of the nomogram was 0.860 (95% confidence interval 0.834?0.887) and calibration plots showed optimal agreement between predicted and observed outcomes.
Conclusions
We constructed and validated a practical nomogram with good discrimination and calibration to predict the risk of kidney failure in C3 glomerulopathy patients at 1, 2, 5 and 10 years.ACKNOWLEDGEMENTS: Work on this study was supported by the Instituto de Salud Carlos III / Fondo Europeo de Desarrollo Regional (ISCIII/FEDER; grants PI16/01685 and PI19/1624) and Red de Investigación Renal (RD12/0021/0029; to M.P.) and the Autonomous Region of Madrid (S2017/BMD-3673; to M.P.). S.R.d.C. is supported by the Ministerio de Economia y Competitividad (grant PID2019-104912RB-I00) and the Autonomous Region of Madrid (grant S2017/BMD-3673). None of the funders had any role in the study design, data collection, analyses, reporting or decision to submit for publication
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