6,676 research outputs found

    On-Line Processing and Computer Control in High Resolution Transmission Electron Microscopy

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    Recent advances in hardware and software make it possible to perform real-time image processing, and to do simultaneous analysis of the image characteristics in the transmission electron microscope (TEM). We have used a commercially available image processor and a suitable computer/TEM interface to build a automated computer-control system for a JEOL 4000EX TEM. We report here the characteristics of the system, which has direct access to all electronic controls of a JEOL 4000EX. The various microscope parameters are set by changing one parameter at a time while the image processor measures a specific image variable such as the variance. From the plot of the variable the program select its optimum value. Through-focus series are taken at the speed of one frame per second, which allows time for reaching electron lens stability, storage of the image, calculation of parameters such as contrast, and the plotting of values; all of this occuring while the image series is being generated. Results obtained using this system for on-line processing and computer control for crystalline and amorphous materials are presented

    Barriers to Breast Cancer-Screening Adherence in Vulnerable Populations

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    : Breast cancer screening through periodic mammography has been effective in decreasing mortality and reducing the impact of this disease. However, adherence to screening does not meet the desired expectations from all populations. The main objective of this review is to explore the barriers that affect adherence to breast cancer-screening programs in vulnerable populations according to race and/or ethnicity in order to propose measures to reduce the lack of adherence. We conducted a search of publications in the PubMed Central and Scopus databases. The eligible criteria for the articles were as follows: original quantitative studies appearing in SJR- and/or JCR-indexed journals from 2016 to 2021 in English or Spanish. Most of them present common barriers, such as race/ethnicity (47%), low socioeconomic (35.3%) and educational levels (29.4%), no family history of cancer and being single (29.4%), medical mistrust and a health information gap (23.5%), lack of private health insurance (17.6%) and not having annual health checks (17.6%). The target populations with the lowest adherence were Black, Asian, Hispanic and foreign women. Implementing awareness campaigns focused on these populations should be promoted, as well as working on diversity, cultural acceptance and respect with healthcare workers, in order to improve breast cancer-screening adherence worldwide

    High coercivity induced by mechanical milling in cobalt ferrite powders

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    In this work we report a study of the magnetic behavior of ferrimagnetic oxide CoFe2O4 treated by mechanical milling with different grinding balls. The cobalt ferrite nanoparticles were prepared using a simple hydrothermal method and annealed at 500oC. The non-milled sample presented coercivity of about 1.9 kOe, saturation magnetization of 69.5 emu/g, and a remanence ratio of 0.42. After milling, two samples attained coercivity of 4.2 and 4.1 kOe, and saturation magnetization of 67.0 and 71.4 emu/g respectively. The remanence ratio MR/MS for these samples increase to 0.49 and 0.51, respectively. To investigate the influence of the microstructure on the magnetic behavior of these samples, we used X-ray powder diffraction (XPD), transmission electron microscopy (TEM), and vibrating sample magnetometry (VSM). The XPD analysis by the Williamson-Hall plot was used to estimate the average crystallite size and strain induced by mechanical milling in the samples

    One Step Non SUSY Unification

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    We show that it is possible to achieve one step gauge coupling unification in a general class of non supersymmetric models which at low energies have only the standard particle content and extra Higgs fields doublets. The constraints are the experimental values of αem\alpha_{em}, αs\alpha_s and sin2θW\sin^2\theta_W at 102GeVs10^2 GeVs, and the lower bounds for FCNC and proton decay rates. Specific example are pointed out.Comment: 10 pages, Latex file,, uses epsf style, Two Postscript figures included. To appear in Europhysics Letter

    Semilinear equations with exponential nonlinearity and measure data

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    We study the existence and non-existence of solutions of the problem [GRAPHICS] where Omega is a bounded domain in R-N, N >=, 3, and it is a Radon measure. We prove that if it 4 pi HN-2, then (0.1) has a unique solution. We also show that the constant 4 pi in this condition cannot be improved. (c) 2005 Elsevier SAS. All rights reserved

    Concentration of atomic hydrogen diffused into silicon in the temperature range 900–1300 °C

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    Boron-doped Czochralski silicon samples with [B]~1017 cm−3 have been heated at various temperatures in the range 800–1300 °C in an atmosphere of hydrogen and then quenched. The concentration of [H-B] pairs was measured by infrared localized vibrational mode spectroscopy. It was concluded that the solubility of atomic hydrogen is greater than [Hs] = 5.6 × 1018 exp( − 0.95 eV/kT)cm−3 at the temperatures investigated

    Spatial prioritization for biodiversity conservation in a megadiverse country

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    Mexico is a biologically megadiverse country, but its biodiversity is endangered due to high deforestation rates. Impacts of land-use/cover-change and climate change are unevenly distributed, which hinders the execution of conservation practices. Consequently, an adequate spatial conservation prioritization is crucial to minimize the negative impacts on biodiversity. Global and national efforts to prioritize conservation show that >45 % of Mexico should be protected. This study develops an applicable spatial conservation prioritization to minimize impacts on biodiversity, under three scenarios. They integrate exposure to land-use/cover-change and climate change scenarios, adaptive capacity to deal with the exposure, and the distribution of endemic species on risk of extinction. Our results show that by 2050 between 11.6 %, 13.9 % and 16.1 % of Mexico would reach score ≥50 in vulnerability (VI), under the optimistic, BAU, and the worst-case scenarios, respectively. By 2070, these figures would rise to 11.9 %, 14.8 % and 18.4 %. Amphibians are the most threatened vertebrates with 62.2 % of endemic species being critically endangered or endangered, while 39.2 %, 11.8 %, and 8.5 % of endemic mammals, birds and reptiles are endangered or critically endangered. The distribution of these amphibians accounts for 3.3 % of the country’s area, while mammals, birds, and reptiles represent 9.9 %, 16.2 %, and 28.7 % of Mexico. Moreover, seven municipalities (0.39 % of the country) represent 30 % of the most vulnerable areas (VI = 70). This study offers relevant information at the levels of municipality and species to help decision-makers prioritize national efforts for the conservation of ecosystems and biodiversity under land-use/cover and climate change. This study is replicable in other regions which aim to adapt decision-making and land management for biodiversity conservation

    Traditional system of goat management. II. Postweaning growth performance of the SRD (Nondescript) goats.

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    Abstract: The pattern of growth of SRD kids from an average of 153 days up to approximately 461 days of age was studied. Weights at the ages of 153 (W 5 ), 181 (W5), 209 (W7 ), 237 (W8 ), 265 (W9 ), 293 (W10 ), 321 (VI 1 ), 349 (W1 2), 461 (W15 ) days and calculated weight gains (G) between every weight interval G5 - (W5 - Weaning weight) through G12 - (W1 2 - W 1 ) were evaluated. Data were initially recorded on 54 kids and diminished thereafter at every interval due to kid mortaiity. The least squares analysis of vaiiance showed a significant season of birth effect (P 0.05) with the exception of type of birth for G 12 (P 0,05), com excecao do tipo de nascimento para G12 (P<0,025). As covariancias de peso da mae ao parto e idade do cabrito no momento da pesagem, foram significativas em algumas idades. Ja para o peso ao nascer, a covariavel foi significativa para P7, P8, P10 (P<0,005), P9 (P<0,001), P6, P11 e G12 (P<0,025)

    Sistema tradicional de manejo de caprinos II. Desempenho de caprinos SRD na fase de pós-aleitamento

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    The pattern of growth of SRD kids from an average of 153 days up to approximately 461 days of age was studied. Weights at the ages of 153 (W5), 181 (W6), 209 (W7), 237 (W8), 265 (W9), 293 (W10), 321 (W11), 349 (W12), 461 (W16) days and calculated weight gains (G) between every weight interval G5 = (W5 - Weaning weight) through G12 = (W12 - W 11) were evaluated. Data were initially recorded on 54 kids and diminished thereafter at every interval due to kid mortality. The least squares analysis of variance showed a significant season of birth effect (P 0.05) with the exception of type of birth for G12 (P 0,05), com exceção do tipo de nascimento para G12 (P < 0,025). As covariâncias de peso da mãe ao parto e idade do cabrito no momento da pesagem, foram significativas em algumas idades. Já para peso ao nascer, a covariável foi significativa para P7, P8, P10 (P < 0,005); P9 (P < 0,001); P6, P11 e G12 (P < 0,025).
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