37 research outputs found

    The effects of seasonal and latitudinal earth infrared radiance variations on ERBS attitude control

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    Analysis performed in the Flight Dynamics Facility by the Earth Radiation Budget Satellite (ERBS) Attitude Determination Support team illustrates the pitch attitude control motion and roll attitude errors induced by Earth infrared (IR) horizon radiance variations. IR scanner and inertial reference unit (IRU) pitch and roll flight data spanning 4 years of the ERBS mission are analyzed to illustrate the changes in the magnitude of the errors on time scales of the orbital period, months, and seasons. The analysis represents a unique opportunity to compare prelaunch estimates of radiance-induced attitude errors with flight measurements. As a consequence of this work the following additional information is obtained: an assessment of an average model of these errors and its standard deviation, a measurement to determine and verify previously proposed corrections to the current Earth IR radiance data base, and the possibility of a mean motion model derived from flight data in place of IRU data for ERBS fine attitude determination

    Milling parameter and tool wear dependent surface quality in micro-milling of brass

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    Short life-time and high tool costs still remain major constraints for the micro-milling process. Understanding the wear mechanisms and their effects on the workpiece quality is essential for efficient tool usage. Usually, wear increases the cutting forces and reduces the emerging surface quality during the micro-milling process. Due to high tool costs, cutting parameters are usually chosen for optimal tool lifetime and/or process time rather than optimal surface quality. The scope of this paper is to investigate the correlation of the process parameters, strategy and wear status of the tool on the resulting surface topography. To reach this goal, micro-milling experiments were conducted, in which several grooves were milled using two end milling tools, new and worn, with a diameter of 1.5 mm and four cutting edges. The cutting speed and feed were varied, as well as the cutting direction. Brass was chosen as workpiece material to ensure a constant wear state of the tools during the experiments. During the cutting process the process forces were recorded and examined for their magnitude and frequency response. Furthermore, the grooves were analyzed optically for their surface roughness. The roughness shows in most cases slightly higher values for the specimen manufactured with the worn tool than the ones done with the new tool. The biggest influence on the surface roughness results from the feed rate, while cutting speed and milling strategy have a smaller influence. The measured cutting forces show similar tendencies, than the resulting surface roughness. The results show also a significant influence of tool wear on the vibration behavior during the process, while the influence of feed rate is mostly negligible. This results partly from the greater tool runout and bigger deviation of the cutting edges

    Current star formation in early-type galaxies and the K+A phenomenon

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    We present the results of an effort to identify and study a sample of the likely progenitors of elliptical (E) and lenticular (S0) K+A galaxies. To achieve this, we have searched a sample ~11,000 nearby (m(r)<16) early-type galaxies selected by morphology from the Sloan Digital Sky Survey (SDSS) Main spectroscopic sample for actively star-forming E and S0 galaxies. Using emission line ratios and visual inspection of SDSS g-band images, we have identified 335 galaxies from the SDSS Fourth Data Release (DR4) as actively star-forming E and S0 galaxies. These galaxies make up about 3% of the total early-type sample and less than 1% of all Main galaxies with m(r)<16. We also identified a sample of ~400 K+A galaxies from DR4 with m(r)<16; more than half of these are E and S0 galaxies. We find that star-forming early-type galaxies and K+A galaxies have similar mass distributions; they are on average less massive than typical early-type galaxies but more massive than the average star-forming galaxy. Both of these types of galaxies are found in higher fractions among all galaxies in lower density environments. The fractions of star-forming E and S0 galaxies and E and S0 K+A galaxies depend on environment in nearly the same way. Model spectra fit to the stellar continua of the star-forming E and S0 galaxies showed that their properties are consistent with star formation episodes of <1 Gyr in duration. The modelling results imply that on average, the star formation episodes will increase the stellar masses by about 4%. There is also evidence that the star-forming regions within these galaxies are rotationally supported.Comment: Accepted to MNRAS, 19 pages, 14 figure

    Evaluation of the zoonotic potential of transmissible mink encephalopathy

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    Successful transmission of Transmissible Mink Encephalopathy (TME) to cattle supports the bovine hypothesis for the still controversial origin of TME outbreaks. Human and primate susceptibility to classical Bovine Spongiform Encephalopathy (c-BSE) and the transmissibility of L-type BSE to macaques indicate a low cattle-to-primate species barrier. We therefore evaluated the zoonotic potential of cattle-adapted TME. In less than two years, this strain induced in cynomolgus macaques a neurological disease similar to L-BSE but distinct from c-BSE. TME derived from another donor species (raccoon) induced a similar disease with even shorter incubation periods. L-BSE and cattle-adapted TME were also transmissible to transgenic mice expressing human prion protein (PrP). Secondary transmissions to transgenic mice expressing bovine PrP maintained the features of the three tested bovine strains (cattle TME, c-BSE and L-BSE) regardless of intermediate host. Thus, TME is the third animal prion strain transmissible to both macaques and humanized transgenic mice, suggesting zoonotic potentials that should be considered in the risk analysis of animal prion diseases for human health. Moreover, the similarities between TME and L-BSE are highly suggestive of a link between these strains, and therefore the possible presence of L-BSE for many decades prior to its identification in USA and Europe. © 2013 by the authors; licensee MDPI, Basel, Switzerland

    Neurologia

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    Sustainability Analysis of Palm Oil Plantation in Central Kalimantan Province, Indonesia

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    Palm oil plantation in Central Kalimantan has started since 1994 until the end of 2011 and it reached 1.256.444 ha areas. However, it has been a lot of criticism from non-governmental organizations, both domestically and abroad because the palm oil plantation alleged negative impact on the economic, social and environment dimensions.   This research uses MDS (Multi-Dimensional Scaling) to analyze the status of palm oil sustainability. Data collected from several agencies, 6 private plantations and interview with relevant experts, village officials, community leaders and 134 households around the private plantation in West Kotawaringin Regency, Central Kalimantan Province. The results show that palm oil plantation simultaneously sustainable with 82.64% index, but partially the index values of economic, social, environment, technology and legality ??dimensions respectively 68.77%, 85.19%, 94.70 %, 79.59% and 94.36%. The low index partially caused by palm oil plantation has not apply all of the principles and criterias of the Roundtable on Sustainable Palm Oil (RSPO), such as the low productivity, planted area of palm oil for society not appropriate yet with the regulation, the community right of land has not resolved yet properly, the poor follow-up on the monitoring results of waste and integrated pest management, standard operating procedures of planted area and mill not fully implemented yet, and the planted area exceed the Land Use Permit that determined by government. Therefore, palm oil plantation in Central Kalimantan needs to apply the principles and criterias of the RSPO continously. Key words: palm oil, sustainable inde

    Relevance of Quality Measurement to Integrative Healthcare in the United States.

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    With the advent of new models for payment and delivery of healthcare services, the use of quality measures for continual improvement of clinical healthcare is now an integral feature of medical practice in the United States. However, quality measurement and quality improvement activities are not common practice among integrative health providers. This article discusses the import and application of quality measurement to the practice of integrative healthcare. It reviews developments in the healthcare quality improvement movement, explores the relevance of quality measures to integrative healthcare, describes examples of the current use of quality measures in integrative health practice, discusses discriminatory policies that may prevent participation in quality improvement by integrative health practitioners, and makes recommendations for practice and policy
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