Argon assisted chemical vapor deposition of CrO2_2: an efficient process leading to high quality epitaxial films

A comparative study of the structural, microstructural and magnetic properties of CrO$_2$ thin films grown onto (110) and (100) TiO$_2$ rutile single crystal substrates by chemical vapor deposition (CVD), using CrO$_3$ as chromium precursor and either oxygen or argon as carrier gas is presented. Our results show that growth under argon carrier gas leads to high quality CrO$_2$ epilayers with structural and magnetic properties similar to those obtained using the more standard oxygen carrier gas. Furthermore, we interpret the larger magnetic coercivity observed for the (110) oriented films in terms of their microstructure, in particular of the highest strain and edge roughness of the building structures of the CrO$_2$ epilayers, which are settled by the substrate crystallographic orientation.Comment: 27 pages, 2 tables, 8 figure

Simple High Performance General Purpose Single Channel Analyser

A simple single channel analyser using standard components is described. High temperature stability (0.002% / °C) and resolution (- 100 uV) is achieved. The two-level generator circuits described allow full DC coupling of the input pulses. The performance of these circuits is discussed in detail and experimental results presente

Gas proportional scintillation counter pulse-signature analysis using digital techniques

The use of short shaping time-constants (50 ns) followed by digital sampling of gas proportional scintillation counter pulses is investigated. Such short shaping time causes each pulse to closely resemble the scintillation light burst, allowing for an effective pulse-signature analysis. Pulse amplitude is obtained by numerical integration of the digital pulse samples. The shorter total pulse durations, lead to pulse-height distributions that are much less dependent on the total interaction rate occurring in the detector. Total interaction rates up to 12 k s-1 can be tolerated without significant degradation of the obtained pulse-height distribution. It was also verified that the maximum throughput achieved by the digital pulse-height analyser improves from 1 to 1.7 k s-1 when using the short shaping time-constants.http://www.sciencedirect.com/science/article/B6TJM-3VR1CVW-2F/1/2e9e952e1c3752048a2954b0dbbdec2

Dual-Cathode CsI Covered Microstrip Plate as VUV High Efficiency Photosensor

A Gas Proportional Scintillation Counter based on a dual-cathode Microstrip Plate covered with a CsI film is described. This new dual-cathode technique has the advantage of increasing the VUV sensitive area of the Microstrip Plate. A detailed description of the technique is presented together with a discussion of the performance. The results obtained for a xenon filled Gas Proportional Scintillation Counter show an improvement of the energy resolution for 5.9 keV X-rays from 12.7%, for a single cathode device, to 11.1% for the dual-cathode devic

Pulse-height-spectrum distortion in xenon gaseous detectors for soft X-rays: experimental results

The results of an experimental determination of the pulse-height distortion in soft X-ray spectra in gaseous xenon detectors are presented. The study confirms previous Monte Carlo simulation results and emphasizes the importance of the electric field in the drift region in reducing spectral degradation while the effect of a strong magnetic field in the same region is shown to be negligibleJNICT (Junta Nacional de Investigação Científica e Tecnológica) Projecto STRDA/P/CEN/422/9

UTILIZING CHERNOFF FACES IN MODELING RESPONSES IN THE EVALUATION OF TRIMESTER SCHEME IMPLEMENTATION

This study uses Chernoff faces to model the responses of students, faculty, and administration staff of a teacher education institution in Manila, Philippines, to the implementation of an Outcomes-Based Teacher Education Curriculum (OBTEC) trimester scheme. Chernoff faces provide a valuable representation to model responses because people are used to studying and reacting to faces. This study used a quantitative research method by analyzing cross-sectional data from the study of the OBTEC trimester scheme. A total of 322 participants were selected through convenience sampling and given a 15-item survey in which possible responses ranged from 1 (strongly disagree) to 6 (strongly agree). The administrators were found to give a generally favorable rating (overall mean = 4.56 agree; overall SD = 0.45) to the OBTEC trimester scheme. The statements most highly rated by the administrators pertain to the success of OBTEC in integrating pedagogical content knowledge training with outcomes-based education, preparation of the students for the teaching profession, and consistency with the K to 12 curriculum. These responses are characterized by the structure of the face, the width of the mouth, and the height of the face, respectively. The most negative aspects of the OBTEC trimester scheme, according to the students, are characterized by hair height, nose width, and a hair style of thin hair that points downward. Chernoff faces were found to be a simple, yet powerful tool to model responses in the evaluation of the OBTEC trimester scheme

Molecular epidemiology of Staphylococcus aureus isolates at different sites in the milk producing dairy farms.

Abstract: The epidemiological relationships between isolated Staphylococcus aureus strains in milk samples of dairy cows, reagent to California Mastitis Test, individual and group milk was demonstrated in different sites of the production fluxogram, in 12 milk-producing farms in the Gameleira region, municipality of Sacramento MG Brazil, so that localization and transmission modes may be identified. Two hundred and forty-four strains out of 446 samples collected at several sites were isolated and bio-chemically characterized as coagulase-positive staphylococcus. Specific chromosome DNA fragment of the species Staphylococcus aureus was amplified to 106 strains and 103 underwent (PFGE). Samples? collection sites with the highest isolation frequency of Staphylococcus aureus strains comprised papillary ostia (31.1%), CMT-reagent cow milk (21.7%), mechanical milking machines? insufflators (21,7%), milk in milk pails (6.6%) and the milk in community bulk tanks (5.6%). Genetic heterogeneity existed among the isolated 103 Staphylococcus aureus strains, since 32 different pulse-types were identified. Pulse-type 1 had the highest similarity among the isolated strains within the different sites of the milk-production fluxogram. Highest occurrence of pulsetype 1 isolates of Staphylococcus aureus strains was reported in samples collected from the papillary ostia (10.6%), followed by milk samples from CMT-reagent dairy cows (5.8%) and mechanical milking machine insufflators (3.8%). The above shows the relevance of these sites in the agents? transmission mechanism within the context of the farms investigated