3,819 research outputs found

    The big oil change: a closer look at the Haber-Menaldo analysis

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    The claim that oil wealth tends to block democratic transitions has recently been challenged by Haber and Menaldo, who use historical data going back to 1800 and conclude there is no “resource curse.” We revisit their data and models, and show they might be correct for the period before the 1970s, but since about 1980, there has been a pronounced resource curse. We argue that oil wealth only became a hindrance to democratic transitions after the transformative events of the 1970s, which enabled developing country governments to capture the oil rents that were previously siphoned off by foreign-owned firms. We also explain why the Haber–Menaldo study failed to identify this: partly because the authors draw invalid inferences from their data and partly because they assume that the relationship between oil wealth and democracy has not changed for the past 200 years

    Validation of a Low Cost Flow Measurement System for Monitoring Vegetative Treatment System Performance

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    In 2006, the Iowa Department of Natural Resources issued National Pollution Discharge Elimination System (NPDES) permits to six feedlots participating in research on the use of vegetative treatment systems (VTSs) to control beef feedlot runoff. While Iowa State University monitors releases from the research portion of these sites, the producers are required to monitor releases from the non-research portions. Additionally, non-research site producers with VTSs and NPDES permits are required to monitor system releases. They are required to measure release volume and collect a sample for analysis. Automated, research oriented open channel flow measurement systems typically cost 7,500toemploy.Muhlbaueret.al(2007)developedalowcostmonitoringsystem(LMS)designedtomeasureopenchannelflowfromaVTSwithatotalcostof7,500 to employ. Muhlbauer et. al (2007) developed a low cost monitoring system (LMS) designed to measure open channel flow from a VTS with a total cost of 1,600. Testing of the LMS by Muhlbauer et. al. (2007) across flow events ranging from one to six hours indicated a mean accuracy of 90.6% in comparison to a flow meter equipped ISCO 6712 portable sampler using a .46m (18”) fiberglass H-flume. Further cost reduction options for a producer include fabrication of a metal H-flume, reducing total system cost to $850. This paper compares the performance of the LMS for estimating both short and longer duration flow events and performance of the fabricated metal flume. The LMS flow measurements were compared to an ISCO 6712 portable sampler and a Krohne Optiflux 4000 flow meter in twelve field tests lasting one and six hours with an accuracy of 88.5% in comparison to the Krohne. Relative to a commercial fiberglass flume, the three fabricated flumes had a mean percent accuracy of 98%

    Differences in Demographic, Behavioral, and Biological Variables Between Those With Valid and Invalid Accelerometry Data: Implications for Generalizability

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    Background: The exclusion of participants with invalid accelerometry data (IAD) may lead to biased results and/or lack of generalizability in large population studies. The purpose of this study was to investigate whether demographic, behavioral, and biological differences occur between those with IAD and valid accelerometry data (VAD) among adults using a representative sample of the civilian noninstitutionalized U.S. population. Methods: Ambulatory participants from NHANES (2003-2004) who were 20-85 years of age were included in the current study and wore an ActiGraph 7164 accelerometer for 7 days. A valid person was defined as those with 4 or more days of at least 10+ hrs of monitoring per day. Among adults (20-85 yrs), 3088 participants provided VAD and 987 provided IAD. Demographic, behavioral, and biological information were obtained from the household interview or from data obtained in a mobile examination center. Results: Differences were observed in age, BMI, ethnicity, education, smoking status, marital status, use of street drugs, current health status, HDL-cholesterol, C-reactive protein, self-reported vigorous physical activity, and plasma glucose levels between those with VAD and IAD. Conclusions: Investigators should take into consideration the potential cut-off bias in interpreting results based on data that excludes IAD participants

    Objectively-Measured Physical Activity and C-Reactive Protein: NHANES 2003–2004

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    The association between physical activity (PA) and C-reactive protein (CRP) is inconsistent, with nearly all studies using self-report measures of PA. The purpose of this study was to examine the association between objectively-measured PA and CRP in U.S. adults and children. Adults (N=2912) and children (N=1643) with valid accelerometer data and CRP data were included in the analyses. Logistic regression analysis was used to assess the odds of meeting physical activity guidelines across CRP quartiles for children and among adults with low, average, and high CRP levels. For adults, after adjustments for age, gender, race, body mass index, smoking, diabetes, and high density lipoprotein cholesterol (HDL-C), compared to those with low CRP levels, odds ratios were 0.59 (CI = 0.45–0.77) and 0.46 (CI = 0.28–0.76) for participants with average and high CRP levels, respectively. For children, after adjustments for age, gender, race, weight status, and HDLC, compared to those in CRP quartile 1, odds ratios were 0.96 (CI = 0.5–1.84), 1.23 (CI = 0.71– 2.12), and 0.79 (CI = 0.33–1.88) for participants in quartiles 2, 3, and 4, respectively. Objectivelymeasured PA is inversely associated with CRP in adults, with PA not related to CRP in children

    An "all-poles" approximation to collinear resummations in the Regge limit of perturbative QCD

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    The procedure to improve the convergence in transverse momentum space of the NLL BFKL kernel using a w-shift is revisited. An accurate approximation to this shift only depending on transverse momenta is presented. This approximation is based on a Bessel function of the first kind with argument depending on the strong coupling and a double logarithm of the ratio of transverse scales. A comparison between different renormalization schemes is also included.Comment: 16 pages, 9 figure

    Azimuthal decorrelation of forward and backward jets at the Tevatron

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    We analyse the azimuthal decorrelation of Mueller-Navelet dijets produced in the collisions at Tevatron energies using a BFKL framework which incorporates dominant subleading effects. We show that these effects significantly reduce the decorrelation yet they are still insufficient to give satisfactory description of experimental data. However a good description of the data is obtained after incorporating within formalism the effective rapidity defined by Del Duca and Schmidt.Comment: 1+9 pages, 6 eps figures; the final version to appear in Phys. Lett. B; one reference added, the use of effective rapidity and the need for BFKL resummmation for small azimuthal angles better motivate

    Different routes, common directions? Activation policies for young people in Denmark and the UK

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    This article analyses and compares the development of activation policies for young people in Denmark and the UK from the mid-1990s. Despite their diverse welfare traditions and important differences in the organisation and delivery of benefits and services for the unemployed, both countries have recently introduced large-scale compulsory activation programmes for young people. These programmes share a number of common features, especially a combination of strong compulsion and an apparently contradictory emphasis on client-centred training and support for participants. The suggested transition from the ‘Keynesian welfare state’ to the ‘Schumpeterian workfare regime’ is used as a framework to discuss the two countries’ recent moves towards activation. It is argued that while this framework is useful in explaining the general shift towards active labour-market policies in Europe, it alone cannot account for the particular convergence of the Danish and British policies in the specific area of youth activation. Rather, a number of specific political factors explaining the development of policies in the mid-1990s are suggested. The article concludes that concerns about mass youth unemployment, the influence of the ‘dependency culture’ debate in various forms, cross-national policy diffusion and, crucially, the progressive re-engineering of compulsory activation by strong centre-left governments have all contributed to the emergence of policies that mix compulsion and a commitment to the centrality of work with a ‘client-centred approach’ that seeks to balance more effective job seeking with human resource development. However, attempts to combine the apparently contradictory concepts of ‘client-centredness’ and compulsion are likely to prove politically fragile, and both countries risk lurching towards an increasingly workfarist approach
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