497 research outputs found

    Novel software techniques for automatic microwave measurements

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    Although many microwave measurement techniques are heavily based on special purpose software, the application of modern software techniques like object oriented programming and new programming language like C++ is seldom used. The impact of such new software solutions can drastically improve the overall design of a microwave test set. The paper presents the design and implementation of a new multiport network analyzer with particular attention to the control program architecture. The use of Object Oriented Programming techniques results in a clear and easy to maintain solution which boosts both the user interface and the overall test set organizatio

    How Will Declining Rates of Marriage Reshape Eligibility for Social Security?

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    For most older people in the United States, Social Security is the major source of income: nine out of ten people age 65 or older receive benefits, which represent an average of 41 percent of their income. Largely as a result of Social Security, poverty rates for the elderly are at an all-time low, just 10 percent. But pockets of poverty persist: older unmarried persons, blacks, and Hispanics experience poverty rates in excess of 20 percent, and over 40 percent of all older single black women live in poverty. People quality for Social Security based either on their work record or their marital status. Most older women receive noncontributory Social Security spouse of widow benefits on the basis of their marital history. For these women, marital status is more important than employment status in shaping old-age financial security. However, the trend to marry and stay married has declined over time in the United States, particularly among black women. This, we hypothesize, means that fewer women will qualify for spouse and widow benefits in coming decades. As a result, Social Security benefits will shrink among the very population that currently reports higher poverty rates, older single women, particularly black women. In this policy brief, we ask: Compared to earlier cohorts, what proportion of white, black, and Hispanic women born in the 1940s, 1950s, and 1960s will enter old age without a marriage that qualifies them for Social Security spouse and widow benefits? We find that the proportion who will reach age 62 without a qualifying marriage, and thus be ineligible for Social Security spouse and widow benefits, is increasing modestly for whites and Hispanics but dramatically for African Americans. Most of these women will be eligible for retired worker benefits under Social Security, but those benefits are not likely to be as large as the benefits they would have received as spouses and widows, had they been eligible. We then discuss a range of policy alternatives, including the possibility of a minimum benefit.Social Security, spousal benefits, widow benefits, poverty, elderly, social welfare, income security.

    A revisited and general Kane’s formulation applied to very flexible multibody spacecraft

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    Abstract. Current space missions require predicting the spacecraft dynamics with considerable reliability. Among the various components of a spacecraft, subsystems like payload, structures, and power depend heavily on the dynamic behavior of the satellite during its operational life. Therefore, to ensure that the results obtained through numerical simulations correspond to the actual behavior, an accurate dynamical model must be developed. In this context, an implementation of Kane’s method is presented to derive the dynamical equations of a spacecraft composed of both rigid and flexible bodies connected via joints in tree topology. Starting from the kinematics of two generic interconnected bodies, a systematic approach is derived and the recursive structure of the equations is investigated. The Kane’s formulation allows a relatively simple derivation of the equation of motion while obtaining the minimum set of differential equations, which implies lower computational time. On the other hand, this formulation excludes reaction forces and torques from the dynamical equations. Nevertheless, in this work a strategy to compute them a posteriori without further numerical integrations is presented. Flexibility is introduced through the standard modal decomposition technique, so that modal shapes obtained by FEA software can be directly utilized to characterize the elastic motion of the flexible bodies. A spacecraft composed of a rigid bus and several flexible appendages is modeled and numerical simulations point out that this systematic method is very effective for this illustrative example

    High prevalence of anti-hepatitis e virus antibodies among blood donors in central Italy, february to march 2014

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    Prevalence of anti-hepatitis E virus (HEV) antibodies is highly variable in developed countries, which seems partly due to differences in assay sensitivity. Using validated sensitive assays, we tested 313 blood donors attending a hospital transfusion unit in central Italy in January and February 2014 for anti-HEV IgG and IgM and HEV RNA. Data on HEV exposure were collected from all donors. Overall anti-HEV IgG prevalence was 49% (153/313). Eating raw dried pig-liver sausage was the only independent predictor of HEV infection (adjusted prevalence rate ratio = 2.14; 95% confidence interval: 1.23–3.74). Three donors were positive for either anti-HEV IgM (n = 2; 0.6%) or HEV RNA (n = 2; 0.6%); they were completely asymptomatic, without alanine aminotransferase (ALT) abnormalities. Of the two HEV RNA-positive donors (both harbouring genotype 3), one was anti-HEV IgG- and IgM-positive, the other was anti-HEV IgG- and IgM-negative. The third donor was positive for anti-HEV IgG and IgM but HEV RNA-negative. HEV infection is therefore hyperendemic among blood donors (80% men 18–64 years-old) from central Italy and associated with local dietary habits. Nearly 1% of donors have acute or recent infection, implying potential transmission to blood recipients. Neither ALT nor anti-HEV IgM testing seems useful to prevent transfusion-transmitted HEV infection. © 2016, European Centre for Disease Prevention and Control

    One year of CNR-IMAA multi-wavelength Raman lidar measurements in coincidence with CALIPSO overpasses: Level 1 products comparison

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    At CNR-IMAA, an aerosol lidar system has operated since May 2000 in the framework of EARLINET (European Aerosol Research Lidar Network), the first lidar network for tropospheric aerosol study on a continental scale. High quality multi-wavelength measurements make this system a reference point for the validation of data products provided by CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations), the first satellite-borne lidar specifically designed for aerosol and cloud study. Since 14 June 2006, dedicated measurements have been performed at CNR-IMAA in coincidence with CALIPSO overpasses. For the first time, results on 1-year comparisons between ground-based multi-wavelength Raman lidar measurements and corresponding CALIPSO lidar Level 1 profiles are presented. A methodology for the comparison is presented and discussed in detail. Night-time cases are considered to take advantage from Raman capability of the ground based lidar. Cases with the detection of cirrus clouds in CALIPSO data are separately analysed for taking into account multiple scattering effects. For cirrus cloud cases, few cases are available to draw any conclusions. For clear sky conditions, the comparison shows good performances of the CALIPSO on-board lidar: the mean relative difference between the ground-based and CALIPSO Level 1 measurements is always within its standard deviation at all altitudes, with a mean difference in the 3–8 km altitude range of (−2±12)%. At altitude ranges corresponding to the typical PBL height observed at CNR-IMAA, a mean difference of (−24±20)% is observed in CALIPSO data, probably due to the difference in the aerosol content at the location of PEARL and CALIPSO ground-track location. Finally, the mean differences are on average lower at all altitude ranges for the closest overpasses (at about 40 km) respect to the 80-km overpasses

    CIAO: the CNR-IMAA advanced observatory for atmospheric research

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    Long-term observations of aerosol and clouds are of crucial importance to understand the weather climate system. At the Istituto di Metodologie per l'Analisi Ambientale of the Italian National Research Council (CNR-IMAA) an advanced atmospheric observatory, named CIAO, is operative. CIAO (CNR-IMAA Atmospheric Observatory) main scientific objective is the long term measurement for the climatology of aerosol and cloud properties. Its equipment addresses the state-of-the-art for the ground-based remote sensing of aerosol, water vapour and clouds including active and passive sensors, like lidars, ceilometers, radiometers, and a radar. This paper describes the CIAO infrastructure, its scientific activities as well as the observation strategy. The observation strategy is mainly organized in order to provide quality assured measurements for satellite validation and model evaluation and to fully exploit the synergy and integration of the active and passive sensors for the improvement of atmospheric profiling. Data quality is ensured both by the application of protocols and dedicated quality assurance programs mainly related to the projects and networks in which the infrastructure is involved. The paper also introduces examples of observations performed at CIAO and of the synergies and integration algorithms (using Raman lidar and microwave profiler data) developed and implemented at the observatory for the optimization and improvement of water vapour profiling. CIAO database represents an optimal basis to study the synergy between different sensors and to investigate aerosol-clouds interactions, and can give a significant contribution to the validation programs of the incoming new generation satellite missions

    How Will Declining Rates of Marriage Reshape Eligibility for Social Security?

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    For most older people in the United States, Social Security is the major source of income: nine out of ten people age 65 or older receive benefits, which represent an average of 41 percent of their income. Largely as a result of Social Security, poverty rates for the elderly are at an all-time low, just 10 percent. But pockets of poverty persist: older unmarried persons, blacks, and Hispanics experience poverty rates in excess of 20 percent, and over 40 percent of all older single black women live in poverty. People quality for Social Security based either on their work record or their marital status. Most older women receive noncontributory Social Security spouse of widow benefits on the basis of their marital history. For these women, marital status is more important than employment status in shaping old-age financial security. However, the trend to marry and stay married has declined over time in the United States, particularly among black women. This, we hypothesize, means that fewer women will qualify for spouse and widow benefits in coming decades. As a result, Social Security benefits will shrink among the very population that currently reports higher poverty rates, older single women, particularly black women. In this policy brief, we ask: Compared to earlier cohorts, what proportion of white, black, and Hispanic women born in the 1940s, 1950s, and 1960s will enter old age without a marriage that qualifies them for Social Security spouse and widow benefits? We find that the proportion who will reach age 62 without a qualifying marriage, and thus be ineligible for Social Security spouse and widow benefits, is increasing modestly for whites and Hispanics but dramatically for African Americans. Most of these women will be eligible for retired worker benefits under Social Security, but those benefits are not likely to be as large as the benefits they would have received as spouses and widows, had they been eligible. We then discuss a range of policy alternatives, including the possibility of a minimum benefit

    Arithmetically Cohen-Macaulay Bundles on complete intersection varieties of sufficiently high multidegree

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    Recently it has been proved that any arithmetically Cohen-Macaulay (ACM) bundle of rank two on a general, smooth hypersurface of degree at least three and dimension at least four is a sum of line bundles. When the dimension of the hypersurface is three, a similar result is true provided the degree of the hypersurface is at least six. We extend these results to complete intersection subvarieties by proving that any ACM bundle of rank two on a general, smooth complete intersection subvariety of sufficiently high multi-degree and dimension at least four splits. We also obtain partial results in the case of threefolds.Comment: 15 page

    Evaluating Native American Bird Use and Bird Assemblage Variability along the Oregon Coast

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    Native American use of birds on the Oregon coast is not well known and has never been synthesized to present a regional understanding. We rectify this by analyzing data from 26 zooarchaeological assemblages, including three previously unpublished bird assemblages: Umpqua/Eden (35DO83), Whale Cove (35LNC60), and the Dunes Site (35CLT27). We employ a series of non-parametric randomization tests to directly evaluate patterns of taxonomic diversity, correlations with nearby breeding colonies, and broader procurement strategies discussed in ethnohistorical accounts. We compare the assemblages to contemporary surveys of naturally beached birds as observed by COASST (Coastal Observation Seabird Survey Team) and evaluate whether archaeological specimens were scavenged from the beach. While 71% of the identified bird remains belong to just three families (Anatidae, Alcidae, and Procellariidae), closer analysis reveals the incredible diversity of birds used by Oregon coast Native Americans. The assemblages vary considerably in terms of taxonomic diversity and composition, leading us to conclude that people used birds opportunistically, likely incorporating multiple strategies, including hunting, collecting beached carcasses and targeting cormorant colonies. We hope that the methods and approaches employed here will inspire other archaeologists to devote more attention to bird assemblages, and how their study can inform conservation efforts
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