135 research outputs found
Results from PAMELA, ATIC and FERMI : Pulsars or Dark Matter ?
It is well known that the dark matter dominates the dynamics of galaxies and
clusters of galaxies. Its constituents remain a mystery despite an assiduous
search for them over the past three decades. Recent results from the
satellite-based PAMELA experiment detect an excess in the positron fraction at
energies between 10-100 GeV in the secondary cosmic ray spectrum. Other
experiments namely ATIC, HESS and FERMI show an excess in the total electron
(\ps + \el) spectrum for energies greater 100 GeV. These excesses in the
positron fraction as well as the electron spectrum could arise in local
astrophysical processes like pulsars, or can be attributed to the annihilation
of the dark matter particles. The second possibility gives clues to the
possible candidates for the dark matter in galaxies and other astrophysical
systems. In this article, we give a report of these exciting developments.Comment: 27 Pages, extensively revised and significantly extended, to appear
in Pramana as topical revie
Neuronal circuitry for pain processing in the dorsal horn
Neurons in the spinal dorsal horn process sensory information, which is then transmitted to several brain regions, including those responsible for pain perception. The dorsal horn provides numerous potential targets for the development of novel analgesics and is thought to undergo changes that contribute to the exaggerated pain felt after nerve injury and inflammation. Despite its obvious importance, we still know little about the neuronal circuits that process sensory information, mainly because of the heterogeneity of the various neuronal components that make up these circuits. Recent studies have begun to shed light on the neuronal organization and circuitry of this complex region
Multi-messenger observations of a binary neutron star merger
On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta
Fish consumption, contaminants and sudden unexpected death in epilepsy: many more benefits than risks
Clinical and laboratory evaluation of schistosomiasis mansoni patients in Brazilian endemic areas
A total of 60% of the territory of Alagoas (AL) is considered endemic for the occurrence of schistosomiasis and the classification of clinical forms of the disease are not known. This paper aimed to evaluate an endemic schistosomiasis population in AL, taking into account the prevalence, classification of the clinical forms and the results of laboratory analyses. The sample consisted of residents in endemic areas. The participants were submitted to a stool examination by the Kato-Katz technique and the diagnosis was based on the reading of two microscopic slides for each sample. The patients whose examinations were positive for schistosomiasis mansoni were submitted to a clinical examination and blood collection. Based on this examination, 8.11% of the study population were positive for schistosomiasis. The medium parasite load was 79.1 ± 174.3 eggs. The intestinal (90.57%) and hepatointestinal (9.43%) forms were found at statistically significant levels (p < 0.001). The results of the present study update information on schistosomiasis in the city of Rio Largo. These data, although referring only to three locations in that city, suggest a decrease either in the parasite load or in the severity of clinical forms
Insegurança alimentar em domicílios brasileiros com crianças menores de cinco anos
This article analyzes food insecurity and hunger in Brazilian families with children under five years of age. This was a nationally representative cross-sectional study using data from the National Demographic and Health Survey on Women and Children (PNDS-2006), in which the outcome variable was moderate to severe food insecurity, measured by the Brazilian Food Insecurity Scale (EBIA). Prevalence estimates and prevalence ratios were generated with 95% confidence intervals. The results showed a high prevalence of moderate to severe food insecurity, concentrated in the North and Northeast regions (30.7%), in economic classes D and E (34%), and in beneficiaries of conditional cash transfer programs (36.5%). Multivariate analysis showed that the socioeconomic relative risks (beneficiaries of conditional cash transfers), regional relative risks (North and Northeast regions), and economic relative risks (classes D and E) were 1.8, 2.0 and 2.4, respectively. Aggregation of the three risks showed 48% of families with moderate to severe food insecurity, meaning that adults and children were going hungry during the three months preceding the survey.Se plantea estudiar el proceso de inseguridad alimentaria y el hambre en los hogares brasileños con niños menores de cinco años. Se trata de un estudio transversal a nivel nacional, realizado con datos de la Encuesta Nacional de Demografía y Salud de la Mujer y la Infancia (PNDS 2006), siendo la variable dependiente la inseguridad alimentaria moderada y grave (IAM+G), medidas mediante la Escala Brasileña de Inseguridad Alimentaria (EBIA). Se generaron estimaciones de prevalencia y razón de prevalencia con intervalos de 95% de confianza. Los resultados muestran una alta prevalencia de IAM+G en el Norte y Nordeste (30,7%), en las clases económicas D y E (34%), y entre los beneficiarios de los programas de transferencias de renta (36,5%). El modelo de análisis multivariado descubrió que los riesgos sociales (beneficiario de programas de transferencias de renta), regionales (Norte y Nordeste) y económicos (clases D y E) fueron de 1,8, 2,0 y 2,4, respectivamente. Mediante la agregación de los tres riesgos se encontró el 48% de los hogares en IAM+G, o sea, adultos y niños tuvieron hambre durante los tres meses anteriores a la encuesta.Este artigo se propõe a estudar o processo de insegurança alimentar e fome em domicílios brasileiros com crianças menores de cinco anos. É um estudo transversal com representatividade nacional executado com dados da Pesquisa Nacional de Demografia e Saúde da Criança e da Mulher (PNDS-2006) tendo como variável dependente a insegurança alimentar moderada e grave (IAM+G), medida através da Escala Brasileira de Insegurança Alimentar (EBIA). Foram geradas estimativas de prevalência e razão de prevalência com intervalos de 95% de confiança. Os resultados apontam para alta prevalência de IAM+G concentrada nas regiões Norte e Nordeste (30,7%), nas classes econômicas D e E (34%) e em beneficiários de Programas de Transferência de Renda (PTR; 36,5%). O modelo de análise multivariada constatou que os riscos sociais (beneficiário de PTR), regionais (Norte e Nordeste) e econômicos (classes D e E) eram de 1,8, 2,0 e 2,4, respectivamente. Agregando-se os três riscos observou-se que 48% dos domicílios encontravam-se em IAM+G, ou seja, crianças e adultos passaram fome nos três meses anteriores ao inquérito.Universidade Federal de São Paulo (UNIFESP)Universidade Estadual de Campinas Faculdade de Ciências MédicasUNIFESPSciEL
The association between alcohol use, alcohol use disorders and tuberculosis (TB). A systematic review
<p>Abstract</p> <p>Background</p> <p>In 2004, tuberculosis (TB) was responsible for 2.5% of global mortality (among men 3.1%; among women 1.8%) and 2.2% of global burden of disease (men 2.7%; women 1.7%). The present work portrays accumulated evidence on the association between alcohol consumption and TB with the aim to clarify the nature of the relationship.</p> <p>Methods</p> <p>A systematic review of existing scientific data on the association between alcohol consumption and TB, and on studies relevant for clarification of causality was undertaken.</p> <p>Results</p> <p>There is a strong association between heavy alcohol use/alcohol use disorders (AUD) and TB. A meta-analysis on the risk of TB for these factors yielded a pooled relative risk of 2.94 (95% CI: 1.89-4.59). Numerous studies show pathogenic impact of alcohol on the immune system causing susceptibility to TB among heavy drinkers. In addition, there are potential social pathways linking AUD and TB. Heavy alcohol use strongly influences both the incidence and the outcome of the disease and was found to be linked to altered pharmacokinetics of medicines used in treatment of TB, social marginalization and drift, higher rate of re-infection, higher rate of treatment defaults and development of drug-resistant forms of TB. Based on the available data, about 10% of the TB cases globally were estimated to be attributable to alcohol.</p> <p>Conclusion</p> <p>The epidemiological and other evidence presented indicates that heavy alcohol use/AUD constitute a risk factor for incidence and re-infection of TB. Consequences for prevention and clinical interventions are discussed.</p
Functional outcomes and rehabilitation strategies in patients treated with chemoradiotherapy for advanced head and neck cancer: a systematic review
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