825 research outputs found

    Improving Risk Predictions by Preprocessing Imbalanced Credit Data

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    Imbalanced credit data sets refer to databases in which the class of defaulters is heavily under-represented in comparison to the class of non-defaulters. This is a very common situation in real-life credit scoring applications, but it has still received little attention. This paper investigates whether data resampling can be used to improve the performance of learners built from imbalanced credit data sets, and whether the effectiveness of resampling is related to the type of classifier. Experimental results demonstrate that learning with the resampled sets consistently outperforms the use of the original imbalanced credit data, independently of the classifier used

    A comparison between the cardio-stress indices of an active and a sedentary population

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    Die moderne leefwyse bring dikwels mee dat ons die belangrikheid van liggaamlike oefening uit die oog verloor. Ons toenemend passiewe leefwyse het gelei tot ’n aansienlike toename in die voorkoms van lewenstylsiektes soos hipertensie en verskeie vorme van vaskulêre patologie. In hierdie studie word die kardiostres-indekse (KSI’e) van aktiewe en sedentêre individue met mekaar vergelyk ten einde insig te verkry in die uitwerking van die aansienlike veranderinge wat in die gemoderniseerde samelewing plaasgevind het. Die aktiewe populasie het bestaan uit 217 weermagrekrute wat reeds 20 weke van hul basiese weermagopleiding voltooi het. Die (n = 126) lede van die sedentêre populasie is gewerf uit ’n tradisionele tersiêre onderwysinstansie. Die deelnemers uit beide populasies moes drie toetssessies bywoon wat gedurende week 1, week 12 en week 20 gehou is. Hulle het ’n nie-ingrypende ViportTMtoets ondergaan om hul KSI, harttempo en QRS-duur te bepaal. Die resultate het getoon dat alhoewel die basislyn vir KSI, bloeddruk en harttempo aanvanklik hoër was onder die aktiewe populasie, die aanvang van die liggaamsoefeningprogram ten opsigte van hierdie drie faktore ’n geleidelike afname en dus ’n verandering in die rigting, en uiteindelik gesonder marges tot gevolg gehad het. Die KSI het egter nie die normale reikwydte ten opsigte van een van die twee groepe bereik nie, wat daarop gedui het dat alhoewel liggaamlike aktiwiteit fisiologiese stresvlakke verminder, ander sleutelfaktore, te wete leefwyse en stresvlakke, ook in ag geneem moet word. Die studie onderskryf die idee dat ’n toename in liggaamlike aktiwiteit die potensiaal het om ’n individu se vatbaarheid vir kardiovaskulêre siektes te verminder. Die studie ondersoek ook die uitwerking van oefening op die hart deur die gebruik van KSI as ’n meetinstrument.A comparison between the cardio-stress indices of an active and a sedentary population. Our modern lifestyle often results in the importance of physical exercise being overlooked. The increasingly passive way of life has resulted in a notable increase in the prevalence of lifestyle disorders, such as hypertension and some forms of vascular pathology. This study compares the cardio-stress indices (CSIs) of active and sedentary individuals to provide insight into the impact of the significant changes that have taken place in the modernised society. The active population consisted of 217 military recruits who had completed 20 weeks of basic military training. The sedentary population (n = 126) was sourced from a traditional tertiary institution where the focus is on attending lectures. Participants from both populations were required to attend three testing sessions, which were held during Week 1, Week 12 and Week 20. Subjects underwent a non-invasive ViportTM test to measure their CSI, heart rate and QRS duration. The results showed that although baseline readings for CSI, blood pressure (BP) and heart rate (HR) were initially higher among the active population, the commencement of the physical training programme resulted in a steady decline in respect of these three factors to approach healthier margins. However, the CSI for neither population reached the normal range, indicating that although physical activity reduces physiological stress levels, other key factors, namely lifestyle stress levels, must also be taken into account.The study supports the notion that increased physical activity has the potential to reduce the predisposition of an individual to cardiovascular disorders and contributes towards establishing the effect of training on heart health by using CSI as a means of measurementhttp://www.satnt.ac.zaay201

    Impact of the COVID-19 pandemic on adolescents’ sexual and reproductive health in low- and middle-income countries

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    Adolescents living in low- and middle-income countries (LMICs) are struggling with accessing sexual and reproductive health (SRH) services, and COVID-19 has escalated the problem. The purpose of this review was to identify and assess the existing literature on the impact of the pandemic on SRH needs and access to services by adolescents in LMICs. A scoping review was conducted to collate findings on the topic. Searches were performed on eight databases. Data were extracted and categorized into various themes. After removing duplicates and performing a full-text reading of all articles, nine articles were included in our review. Our findings generated several themes related to adolescents’ sexual and reproductive health during the COVID-19 pandemic. These include (1) limited access to sexual and reproductive health services, (2) school closure and increased rate of early marriages, (3) sexual or intimate partner violence during COVID-19, (4) disruption in maternity care, (5) adolescents’ involvement in risky or exploitative work, (6) intervention to improve sexual and reproductive health services during COVID-19, and (7) policy development related to adolescent sexual and reproductive health. Several recommendations were made on policies—for instance, the use of telemedicine and community-based programs as a way to deliver SRH services to adolescents during and after a pandemic

    Global Search for New Physics with 2.0/fb at CDF

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    Data collected in Run II of the Fermilab Tevatron are searched for indications of new electroweak-scale physics. Rather than focusing on particular new physics scenarios, CDF data are analyzed for discrepancies with the standard model prediction. A model-independent approach (Vista) considers gross features of the data, and is sensitive to new large cross-section physics. Further sensitivity to new physics is provided by two additional algorithms: a Bump Hunter searches invariant mass distributions for "bumps" that could indicate resonant production of new particles; and the Sleuth procedure scans for data excesses at large summed transverse momentum. This combined global search for new physics in 2.0/fb of ppbar collisions at sqrt(s)=1.96 TeV reveals no indication of physics beyond the standard model.Comment: 8 pages, 7 figures. Final version which appeared in Physical Review D Rapid Communication

    Observation of Orbitally Excited B_s Mesons

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    We report the first observation of two narrow resonances consistent with states of orbitally excited (L=1) B_s mesons using 1 fb^{-1} of ppbar collisions at sqrt{s} = 1.96 TeV collected with the CDF II detector at the Fermilab Tevatron. We use two-body decays into K^- and B^+ mesons reconstructed as B^+ \to J/\psi K^+, J/\psi \to \mu^+ \mu^- or B^+ \to \bar{D}^0 \pi^+, \bar{D}^0 \to K^+ \pi^-. We deduce the masses of the two states to be m(B_{s1}) = 5829.4 +- 0.7 MeV/c^2 and m(B_{s2}^*) = 5839.7 +- 0.7 MeV/c^2.Comment: Version accepted and published by Phys. Rev. Let

    Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV

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    Results are presented from a search for a W' boson using a dataset corresponding to 5.0 inverse femtobarns of integrated luminosity collected during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV. The W' boson is modeled as a heavy W boson, but different scenarios for the couplings to fermions are considered, involving both left-handed and right-handed chiral projections of the fermions, as well as an arbitrary mixture of the two. The search is performed in the decay channel W' to t b, leading to a final state signature with a single lepton (e, mu), missing transverse energy, and jets, at least one of which is tagged as a b-jet. A W' boson that couples to fermions with the same coupling constant as the W, but to the right-handed rather than left-handed chiral projections, is excluded for masses below 1.85 TeV at the 95% confidence level. For the first time using LHC data, constraints on the W' gauge coupling for a set of left- and right-handed coupling combinations have been placed. These results represent a significant improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe

    Search for the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV

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    A search for a Higgs boson decaying into two photons is described. The analysis is performed using a dataset recorded by the CMS experiment at the LHC from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross section of the standard model Higgs boson decaying to two photons. The expected exclusion limit at 95% confidence level is between 1.4 and 2.4 times the standard model cross section in the mass range between 110 and 150 GeV. The analysis of the data excludes, at 95% confidence level, the standard model Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The largest excess of events above the expected standard model background is observed for a Higgs boson mass hypothesis of 124 GeV with a local significance of 3.1 sigma. The global significance of observing an excess with a local significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is estimated to be 1.8 sigma. More data are required to ascertain the origin of this excess.Comment: Submitted to Physics Letters

    Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

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    This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio

    Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS

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    The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4 fb^-1, these states are reconstructed through their radiative decays to Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table, corrected author list, matches final version in Physical Review Letter
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