1,093 research outputs found

    Business Employment Dynamics: Tabulations by Employer Size

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    The gross job gains and gross job loss statistics from the BLS Business Employment Dynamics (BED) program measure the large gross job flows that underlie the quarterly net change in employment. In the fourth quarter of 2004, employment grew by 869,000 jobs. This growth is the sum of 8.1 million gross job gains from opening and expanding establishments, and 7.2 million gross job losses from contracting and closing establishments. The new BED data have captured the attention of economists and policymakers across the country, and these data are becoming a major contributor to our understanding of employment growth and business cycles in the U.S. economy. Following the initial release of the BED data in September 2003, the BED data series expanded in May 2004 with the release of industry statistics. The BLS then began work on tabulations by size class. The production of size-class statistics is a complex task involving several economic and statistical issues. Although it is trivial to classify a business into a size class in any given quarter, it is difficult to classify a business into a size class for a longitudinal analysis of employment growth. Several different classifications exist, and many of these possible classifications have appealing theoretical and statistical properties. Furthermore, these alternative classification methodologies result in sharply different portraits of employment growth by size class. In this article, we discuss the alternative statistical methodologies that the BLS considered for creating size class tabulations from the Business Employment Dynamics data. Our primary focus is on four methodologies: quarterly base-sizing, annual base-sizing, mean-sizing, and dynamic-sizing. We discuss the evaluation criteria that BLS considered for choosing its official size class methodology.gross job gains; gross job losses; business employment dynamics; size-class statistics; dynamic-sizing

    Stubble trouble! Moisture, pathogen fitness and cereal type drive colonisation of cereal stubble by three fungal pathogens

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    Stubble-borne cereal diseases are a major constraint to production in Australia, with associated costs rising as a result of increased adoption of conservation agriculture systems. The fungal pathogens that cause these diseases can saprotrophically colonise retained cereal residues, which may further increase inoculum levels post-harvest. Hence, saprotrophic colonisation by the stubble-borne fungal pathogens Fusarium pseudograminearum, Pyrenophora tritici-repentis and Bipolaris sorokiniana were compared under a range of moisture conditions for stubble of six cereal varieties (two bread wheat, two barley, one durum wheat and one oat). Sterile cereal stubble was inoculated separately with two isolates of each pathogen and placed, standing, under constant relative humidity conditions (90, 92.5, 95, 97.5 and 100%) for 7 days at 25 °C. Stubble was then cultured in increments of 1 cm to determine the percentage colonisation height of each tiller. Fusarium pseudograminearum colonised farther within tillers, leaving a greater proportion of the standing stubble colonised compared with B. sorokiniana and P. tritici-repentis, suggesting F. pseudograminearum has higher saprotrophic fitness. Saprotrophic colonisation also increased with increasing relative humidity for all pathogens and varied by cereal type. Disease management strategies, such as reduced cereal harvest height, may limit saprotrophic colonisation and improve stubble-borne disease management in conservation agriculture systems

    Is there a disease downside to stripper fronts? Harvest height implications for Fusarium crown rot management

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    Take home messages • Taller standing stubble allowed vertical progression of the Fusarium crown rot fungus within the stubble after harvest, whilst short stubble prevented further growth (i.e. vertical growth was limited to the height of the cut stubble). • Stripper fronts, which leave higher standing stubble, may increase stubble-borne disease inoculum after harvest of an infected crop, especially if wet fallow conditions are experienced. • In high-risk situations, such as an infected crop with high biomass, cutting the crop shorter at harvest will limit further inoculum development within the stubble after harvest (beyond the levels already present at harvest). • Cutting infected cereal stubble shorter prior to rotation with shorter-stature crops such as chickpea or lentils also prevents the dispersal of infected stubble when harvesting these shorter break crops

    Molecular epidemiology of human rhinovirus infections in Kilifi, coastal Kenya

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    This study reports pediatric surveillance over 3 years for human rhinovirus (HRV) at the District Hospital of Kilifi, coastal Kenya. Nasopharyngeal samples were collected from children presenting at outpatient clinic with no signs of acute respiratory infection, or with signs of upper respiratory tract infection, and from children admitted to the hospital with lower respiratory tract infection. Samples were screened by real-time reverse transcriptase polymerase chain reaction (real-time RT-PCR) and classified further to species by nucleotide sequencing of the VP4/VP2 junction. Of 441 HRV positives by real-time RT-PCR, 332 were classified to species, with 47% (155) being HRV-A, 5% (18) HRV-B, and 48% (159) HRV-C. There was no clear seasonal pattern of occurrence for any species. The species were present in similar proportions in the inpatient and outpatient sample sets, and no significant association between species distribution and the severity of lower respiratory tract infection in the inpatients could be determined. HRV sequence analysis revealed multiple but separate clusters in circulation particularly for HRV-A and HRV-C. Most HRV-C clusters were distinct from reference sequences downloaded from GenBank. In contrast, most HRV-A and HRV-B sequences clustered with either known serotypes or strains from elsewhere within Africa and other regions of the world. This first molecular epidemiological study of HRV in the region defines species distribution in accord with reports from elsewhere in the world, shows considerable strain diversity and does not identify an association between any species and disease severity

    s-Process Studies In the Light of New Experimental Cross Sections: Distribution of Neutron Fluences and r-Process Residuals

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    A best set of neutron-capture cross sections has been evaluated for the most important s-process isotopes. With this data base, s-process studies have been carried out using the traditional model which assumes a steady neutron flux and an exponential distribution of neutron irradiations. The calculated sigma-N curve is in excellent agreement with the empirical sigma-N-values of pure s-process nuclei. Simultaneously, good agreement is found between the difference of solar and s-process abundances and the abundances of pure r-process nuclei. The abundance pattern of the iron group elements where s-process results complement the abundances obtained from explosive nuclear burning is discussed. The results obtained from the traditional s-process model such as seed abundances, mean neutron irradiations, or neutron densities are compared to recent stellar model calculations which assume the He-burning shells of red giant stars as the site for the s-process

    Individual-specific changes in the human gut microbiota after challenge with enterotoxigenic Escherichia coli and subsequent ciprofloxacin treatment

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    Acknowledgements The authors wish to thank Mark Stares, Richard Rance, and other members of the Wellcome Trust Sanger Institute’s 454 sequencing team for generating the 16S rRNA gene data. Lili Fox Vélez provided editorial support. Funding IA, JNP, and MP were partly supported by the NIH, grants R01-AI-100947 to MP, and R21-GM-107683 to Matthias Chung, subcontract to MP. JNP was partly supported by an NSF graduate fellowship number DGE750616. IA, JNP, BRL, OCS and MP were supported in part by the Bill and Melinda Gates Foundation, award number 42917 to OCS. JP and AWW received core funding support from The Wellcome Trust (grant number 098051). AWW, and the Rowett Institute of Nutrition and Health, University of Aberdeen, receive core funding support from the Scottish Government Rural and Environmental Science and Analysis Service (RESAS).Peer reviewedPublisher PD

    Treating and Preventing Influenza in Aged Care Facilities: A Cluster Randomised Controlled Trial

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    PMCID: PMC3474842This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

    How a bird is an island

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    Replicate adaptive radiations occur when lineages repeatedly radiate and fill new but similar niches and converge phenotypically. While this is commonly seen in traditional island systems, it may also be present in host-parasite relationships, where hosts serve as islands. In a recent article in BMC Biology, Johnson and colleagues have produced the most extensive phylogeny of the avian lice (Ischnocera) to date, and find evidence for this pattern. This study opens the door to exploring adaptive radiations from a novel host-parasite perspective
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