Design concepts for the Cherenkov Telescope Array CTA: an advanced facility for ground-based high-energy gamma-ray astronomy

Ground-based gamma-ray astronomy has had a major breakthrough with the impressive results obtained using systems of imaging atmospheric Cherenkov telescopes. Ground-based gamma-ray astronomy has a huge potential in astrophysics, particle physics and cosmology. CTA is an international initiative to build the next generation instrument, with a factor of 5-10 improvement in sensitivity in the 100 GeV-10 TeV range and the extension to energies well below 100 GeV and above 100 TeV. CTA will consist of two arrays (one in the north, one in the south) for full sky coverage and will be operated as open observatory. The design of CTA is based on currently available technology. This document reports on the status and presents the major design concepts of CTA.

Design concepts for the Cherenkov Telescope Array CTA: an advanced facility for ground-based high-energy gamma-ray astronomy

Ground-based gamma-ray astronomy has had a major breakthrough with the impressive results obtained using systems of imaging atmospheric Cherenkov telescopes. Ground-based gamma-ray astronomy has a huge potential in astrophysics, particle physics and cosmology. CTA is an international initiative to build the next generation instrument, with a factor of 5-10 improvement in sensitivity in the 100 GeV-10 TeV range and the extension to energies well below 100 GeV and above 100 TeV. CTA will consist of two arrays (one in the north, one in the south) for full sky coverage and will be operated as open observatory. The design of CTA is based on currently available technology. This document reports on the status and presents the major design concepts of CTA.

Scale-up model obtained from the rheological analysis of highly concentrated emulsions prepared at three scales

We examine the scale invariants in the preparation of highly concentrated w/o emulsions at different scales and in varying conditions. The emulsions are characterized using rheological parameters, owing to their highly elastic behavior. We first construct and validate empirical models to describe the rheological properties. These models yield a reasonable prediction of experimental data. We then build an empirical scale-up model, to predict the preparation and composition conditions that have to be kept constant at each scale to prepare the same emulsion. For this purpose, three preparation scales with geometric similarity are used. The parameter N¿D^α, as a function of the stirring rate N, the scale (D, impeller diameter) and the exponent α (calculated empirically from the regression of all the experiments in the three scales), is defined as the scale invariant that needs to be optimized, once the dispersed phase of the emulsion, the surfactant concentration, and the dispersed phase addition time are set. As far as we know, no other study has obtained a scale invariant factor N¿Dα for the preparation of highly concentrated emulsions prepared at three different scales, which covers all three scales, different addition times and surfactant concentrations. The power law exponent obtained seems to indicate that the scale-up criterion for this system is the power input per unit volume (P/V).

Estratégias para aumento de sensibilidade em espectrofotometria UV-VIS

Spectrophotometry is one of the most widespread analytical techniques due to its simplicity, reliability, and low-cost instrumentation for both direct measurements and coupled to other techniques or processes such as chromatography, electrophoresis and flow analysis. However, the application is often limited by sensitivity. This article describes some advances that greatly improve the performance of spectrophotometric measurements, especially in order to increase sensitivity, including the employment of liquid-core waveguides and solid-phase spectrophotometry.

Probing quantum gravity using photons from a flare of the active galactic nucleus Markarian 501 observed by the MAGIC telescope

We analyze the timing of photons observed by the MAGIC telescope during a flare of the active galactic nucleus Mkn 501 for a possible correlation with energy, as suggested by some models of quantum gravity (QG), which predict a vacuum refractive index similar or equal to 1 + (E/M-QGn)(n), n = 1, 2. Parametrizing the delay between gamma-rays of different energies as Delta t = +/-tau E-1 or Delta t = +/-tau E-q(2), we find tau(1) = (0.030 +/- 0.012) s/GeV at the 2.5-sigma level, and tau(q) = (3.71 +/- 2.57) x 10(-6) s/GeV2, respectively. We use these results to establish lower limits M-QG1 > 0.21 X 10(18) GeV and M-QG2 > 0.26 x 10(11) GeV at the 95% C.L. Monte Carlo studies confirm the MAGIC sensitivity to propagation effects at these levels. Thermal plasma effects in the source are negligible, but we cannot exclude the importance of some other source effect.

Microquasars: uns sistemes estel.lars extraordinaris

Quan alcem els ulls en una nit estel·lada d'estiu, sovint veiem una banda de llum que travessa la volta del cel amb una lluentor blanquinosa ...

X-ray and radio observations of RX J1826.2-1450/LS 5039

RX J1826.2-1450/LS 5039 has been recently proposed to be a radio emitting high mass X-ray binary. In this paper, we present an analysis of its X-ray timing and spectroscopic properties using different instruments on board the RXTE satellite. The timing analysis indicates the absence of pulsed or periodic emission on time scales of 0.02-2000 s and 2-200 d, respectively. The source spectrum is well represented by a power-law model, plus a Gaussian component describing a strong iron line at 6.6 keV. Significant emission is seen up to 30 keV, and no exponential cut-off at high energy is required. We also study the radio properties of the system according to the GBI-NASA Monitoring Program. RX J1826.2-1450/LS 5039 continues to display moderate radio variability with a clearly non-thermal spectral index. No strong radio outbursts have been detected after several months.

Evidence of Halpha periodicities in LSI+61·303

We present the results of analyzing H$\alpha$ spectra of the radio emitting X-ray binary LS I+61303. For the first time, the same 26.5 d radio period is clearly detected in the H$\alpha$ emission line. Moreover, the equivalent width and the peak separation of the H$\alpha$ emission line seem also to vary over a time scale of 1600 days. This points towards the $\sim4$ yr modulation, detected in the radio outburst amplitude, being probably a result of variations in the mass loss rate of the Be star and/or density variability in the circumstellar disk. In addition, the dependence of the peak separation from the equivalent width informs us that the LS I+61303 circumstellar disk is among the densest of Be-stars.

V-band observations of V4641 Sagittarii

In this note we report high time resolution V Johnson photometry of the microquasar V4641 Sgr (SAX J1819.3-2525 - XTE J1819-254). This source was discovered as an X-ray transient by BeppoSAX and RossiXTE satellites (In't Zand et al. 1999; Markwardt et al. 1999). On 1999 September, a very fast transient optical and X-ray outburst was observed, reaching up to ...

La percepción del paciente crítico sobre los cuidados enfermeros: una aproximación al concepto de satisfacción

Introducción: El grado de satisfacción es un indicador fundamental de la calidad asistencial. Existen numerosos instrumentos que miden la satisfacción con los cuidados enfermeros, aunque no responden a la realidad del paciente crítico ni a nuestro contexto. Objetivos: Explorar y comprender la satisfacción de los pacientes ingresados en Cuidados Intensivos de un hospital nivel iii con los cuidados enfermeros, para definir e identificar las dimensiones del concepto de satisfacción desde su punto de vista. Material y métodos: Estudio cualitativo según la teoría fundamentada en 3 unidades de Cuidados Intensivos de 34 boxes individuales. Muestreo teórico. La muestra, tras la saturación de datos, fue de 19 participantes. La recogida de datos fue a través de la entrevista en profundidad y diario de campo. Análisis de contenido según teoría fundamentada. Se siguieron los criterios de rigor de Guba y Lincoln. Informe favorable del comité de ética del centro y consentimiento informado. Resultados: Emergen 4 categorías: definición y dimensiones del concepto de satisfacción, expectativas y vivencias. Los participantes incluyen en su definición de satisfacción las dimensiones: competencias profesionales, cuidados humanos, técnicos y continuados. La combinación de estos elementos produce sentimientos de seguridad, tranquilidad, estar vigilado, sentirse persona, percibiendo una relación cercana y de confianza con la enfermera que realiza cuidados individualizados. Conclusiones: La definición y las dimensiones del concepto de satisfacción desde el punto de vista del paciente muestran los aspectos importantes para la persona además de clarificar sus dimensiones, permitiendo la construcción de instrumentos más acordes con el contexto y su percepción real.

Development of an instrument to measure the degree of critical patient's satisfaction with nursing care: research protocol

Aim: To investigate and understand patient's satisfaction with nursing care in the intensive care unit to identify the dimensions of the concept of"satisfaction" from the patient's point of view. To design and validate a questionnaire that measures satisfaction levels in critical patients. Background: There are many instruments capable of measuring satisfaction with nursing care; however, they do not address the reality for critical patients nor are they applicable in our context. Design: A dual approach study comprising: a qualitative phase employing Grounded Theory and a quantitative and descriptive phase to prepare and validate the questionnaire. Methods: Data collection in the qualitative phase will consist of: in-depth interview after theoretical sampling, on-site diary and expert discussion group. The sample size will depend on the expected theoretical saturation n = 27-36. Analysis will be based on Grounded Theory. For the quantitative phase, the sampling will be based on convenience (n = 200). A questionnaire will be designed on the basis of qualitative data. Descriptive and inferential statistics will be used. The validation will be developed on the basis of the validity of the content, the criteria of the construct and reliability of the instrument by the Cronbach's alpha and test-retest approach. Approval date for this protocol was November 2010. Discussion: Self-perceptions, beliefs, experiences, demographic, socio-cultural epistemological and political factors are determinants for satisfaction, and these should be taken into account when compiling a questionnaire on satisfaction with nursing care among critical patients.

Percepción de las enfermeras de UCI en relación al cuidado satisfactorio: convergencias y divergencias con la percepción del paciente crítico

Objetivo: Explorar las convergencias y divergencias entre la percepción de las enfermeras y los pacientes críticos, en relación a los cuidados satisfactorios proporcionados y recibidos. Métodos: Forma parte de un estudio cualitativo más amplio, según la Teoría Fundamentada. Realizado en 3 Unidades de Cuidados Intensivos con 34 boxes. Muestreo teórico por perfiles con n = 19 pacientes y n = 7 enfermeras tras la saturación de datos. El reclutamiento de pacientes incluidos en los perfiles de edad avanzada y larga estancia se dilató en el tiempo por la baja incidencia de estos. La recogida de datos consistió en: entrevista en profundidad a los pacientes críticos, grupo de discusión de enfermeras expertas en el cuidado al paciente crítico y diario de campo. Análisis temático de Teoría Fundamentada según Strauss y Corbin: codificación abierta, axial y selectiva. Se siguieron los criterios de rigor de Guba y Lincoln, de calidad de Calderón y los de reflexividad ética de Gastaldo y McKeever. Se obtuvo informe favorable del comité de ética del centro y consentimiento informado de los participantes. Resultados: Emergen 4 categorías coincidentes: las competencias profesionales, los cuidados humanos, técnicos y continuados. La combinación de estos elementos producen sentimientos de seguridad, tranquilidad, sentirse persona permitiendo al paciente una relación cercana y de confianza con la enfermera que realiza cuidados individualizados. No se han encontrado categorías divergentes. Conclusiones: Las percepciones de las enfermeras en relación a los cuidados coinciden con las percepciones de los pacientes críticos tanto en la definición como en las dimensiones sobre el cuidado satisfactorio.

MATERIAIS VÍTREOS E LUZ: PARTE 2

In this second part it will be discussed some photonic applications of glassy and glass ceramic thin films which can be used as planar waveguides. Some photonic applications require certain specifications of glass, which can be quantified by studying the nonlinear optical properties of the materials. Therefore, a brief introduction of these phenomena is discussed, as well as the use of femtosecond lasers to manipulate the composition or for the preparation of waveguides into glasses. Finally, the article will address a brief introduction on microstructured optical fibers and commercial application prospects for these devices.

Abscesso hepático piogênico por corpo estranho

Pyogenic hepatic abscess by a foreign body is a rare disease and its diagnosis is habitually made during necropsy. The authors present a case of a woman operated because of a pyogenic hepatic abscess, in the interior of which bristle made of material of vegetable origin were encountered and identified in the laboratory as the principal rib of a leaf, known in Brazil as piaçava. The hepatic abscess was drained and the patient was discharged. The probable mechanism for the formation of the hepatic abscess consisted of the accidental ingestion, perforation of the intestines and penetration in the liver.

Osteocondromatose múltipla hereditária com envolvimento costal

This is a case report on Hereditary Multiple Osteochondromatosis (HMO) with rib involvement. The authors present aspects of thoracic surface anatomy, and thoracic images (X-rays, computed tomography, magnetic nuclear resonance), as well as the operating procedure.