2,909 research outputs found
Seasonal plasticity and correlations among butterfly wing color patterns: Insights into modularity
Dealing with the wide ranges of temperatures throughout the year can be a challenge for ectothermic animals like insects. Phenotypic plasticity, the development of different phenotypes depending on the environment, is one way that animals can combat this problem. However, traits are often integrated and share developmental or genetic mechanisms which can limit the adaptive response of an individual trait. Modules, groups of traits that vary together but are independent of other traits, often share developmental mechanisms and therefore can facilitate the evolution of these adaptive traits. The seasonally variable melanistic wing patterns elements of the Colias butterfly are an ideal model to study modularity because of their homologies and shared developmental requirement of the pigment, melanin. The seasonal variation of the ventral hindwing is adaptively advantageous for thermoregulation, but the variation of other melanistic traits has received far less attention. This goal of this project was to identify which melanistic traits vary seasonally and examine how they correlate with each other and with the ventral hindwing in Colias butterflies using statistical analyses. The results show that melanistic wing pattern elements are seasonally plastic and modular. Furthermore, these modules align with elements of the nymphalid groundplan. Because melanized basal trait elements show similar patterns of seasonal plasticity as the ventral hindwing, they may share its thermoregulatory function. Additionally, the potential underlying mechanisms of the seasonal plasticity and modularity of these melanistic wing pattern elements are discussed
Music and place on Oklahoma City's Deep Deuce
Thesis (M.A.)--University of Oklahoma, 1996.Includes bibliographical references
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Marijuana and Crime: A Critique and Proposal
Of the plethora of social problems with which government has had to contend in recent history, few have generated more controversy than the non-therapeutic use of drugs. Many of those which are currently in common use did not exist fifty years ago; but the most dramatic growth in non-therapeutic use has been experienced with a drug that man has known for centuries: marijuana.1 Known generically as Cannabis sativa, internationally as Indian hemp, popularly as marijuana, and in American slang as "pot" or "grass," the drug was introduced to the United States as an intoxicant by itinerate Mexican farm workers in the early decades of this century. The acknowledged use of marijuana in the ghettos and communities of ethnic minorities for several decades stimulated no public outcry with the exception of the sensational press campaigns which led to the passage of the Marihuana Tax Act of 1937
One and a Half Decades of Apartment Loss and Condominium Growth: Changes in Chicago\u27s Residential Building Stock
We use data from the Cook County Assessor to document the decline in Chicago apartments and growth in condominium units from 1989 to 2004. While the total number of housing units in Chicago remained approximately constant at a little over one million, we find that at least 44,637 and perhaps as many as 97,894 apartment units were removed from Chicago’s housing stock during this period. Over the same period 102,408 condominium units have been added to the housing stock. We provide tables and maps that show the changes by in small apartments (less than six units), large apartments (7+ units) and condominiums by community area. Loss of small and large apartment buildings has been widespread across the entire city. Condominium growth has been most intense on the Northeast, Near South and Near West Sides. Some, but not all, of the community areas that lost large numbers of apartments gained condominiums. On average, across the city as a whole, for each 1,000 additional condominium units a community area gained, it lost 27 small apartment buildings and about 6 large apartment buildings
Best practice for analysis of shared clinical trial data
BACKGROUND:
Greater transparency, including sharing of patient-level data for further research, is an increasingly important topic for organisations who sponsor, fund and conduct clinical trials. This is a major paradigm shift with the aim of maximising the value of patient-level data from clinical trials for the benefit of future patients and society. We consider the analysis of shared clinical trial data in three broad categories: (1) reanalysis - further investigation of the efficacy and safety of the randomized
3 intervention, (2) meta-analysis, and (3) supplemental analysis for a research question that is not directly assessing the randomized intervention.
DISCUSSION:
In order to support appropriate interpretation and limit the risk of misleading findings, analysis of shared clinical trial data should have a pre-specified analysis plan. However, it is not generally possible to limit bias and control multiplicity to the extent that is possible in the original trial design, conduct and analysis, and this should be acknowledged and taken into account when interpreting results. We highlight a number of areas where specific considerations arise in planning, conducting, interpreting and reporting analyses of shared clinical trial data. A key issue is that that these analyses essentially share many of the limitations of any post hoc analyses beyond the original specified analyses. The use of individual patient data in meta-analysis can provide increased precision and reduce bias. Supplemental analyses are subject to many of the same issues that arise in broader epidemiological analyses. Specific discussion topics are addressed within each of these areas.
SUMMARY:
Increased provision of patient-level data from industry and academic-led clinical trials for secondary research can benefit future patients and society. Responsible data sharing, including transparency of the research objectives, analysis plans and of the results will support appropriate interpretation and help to address the risk of misleading results and avoid unfounded health scares
Application of Appropriateness Criteria to Stress Single-Photon Emission Computed Tomography Sestamibi Studies and Stress Echocardiograms in an Academic Medical Center
ObjectivesThe purpose of this study was to apply published appropriateness criteria for single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) in a single academic medical center.BackgroundThe American College of Cardiology Foundation (ACCF) and the American Society of Nuclear Cardiology (ASNC) have developed appropriateness criteria for stress SPECT MPI to address concern about the growth in cardiac imaging studies.MethodsWe retrospectively examined 284 patients who underwent stress SPECT MPI and 298 patients who underwent stress echocardiography before publication of these criteria.ResultsThe overall level of agreement in characterizing appropriateness between 2 experienced cardiovascular nurse abstractors was modest (kappa = 0.56), but noticeably poorer (kappa = 0.27) for patients with previous SPECT or echo studies. Similar percentages of each imaging modality were assigned to the 3 appropriateness categories: 64% of stress SPECT and 64% of stress echo studies were classified appropriate; 11% of stress SPECT and 9% of stress echo were of uncertain appropriateness; and 14% of stress SPECT and 18% of stress echo were inappropriate. Of the inappropriate studies, 88% were performed for 1 of 4 indications. Approximately 10% of the patients were unclassifiable.ConclusionsApplication of existing SPECT MPI appropriateness criteria is demanding and requires an established database or detailed data collection, as well as a number of assumptions. Fourteen percent of stress SPECT studies and 18% of stress echo studies were performed for inappropriate reasons. Quality improvement efforts directed at reducing the number of these inappropriate studies may improve efficiency in the health care system
Product innovation as a mediator in the impact of R&D expenditure and brand equity on marketing performance
This study combines the signaling theory and dynamic marketing capabilities perspective to investigate the mediating role of product innovation in the influence of R&D expenditure and brand equity on marketing performance. The study shows that MNC firms are able to use R&D expenditure to improve their product innovation and market share to a greater extent compared to SME and retailer firms. However, the stronger brand equity of MNC firms may actually hurt the performance of their new products by inhibiting product innovation. The authors use regression and probit analysis to study a panel data for 1356 food brands. Overall, this research provides fresh insights into the process by which R&D expenditure and brand equity affect product innovation and marketing performance in highly competitive product categories
Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector
The inclusive and dijet production cross-sections have been measured for jets
containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass
energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The
measurements use data corresponding to an integrated luminosity of 34 pb^-1.
The b-jets are identified using either a lifetime-based method, where secondary
decay vertices of b-hadrons in jets are reconstructed using information from
the tracking detectors, or a muon-based method where the presence of a muon is
used to identify semileptonic decays of b-hadrons inside jets. The inclusive
b-jet cross-section is measured as a function of transverse momentum in the
range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet
cross-section is measured as a function of the dijet invariant mass in the
range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets
and the angular variable chi in two dijet mass regions. The results are
compared with next-to-leading-order QCD predictions. Good agreement is observed
between the measured cross-sections and the predictions obtained using POWHEG +
Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet
cross-section. However, it does not reproduce the measured inclusive
cross-section well, particularly for central b-jets with large transverse
momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final
version published in European Physical Journal
Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector
Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente
Jet energy measurement with the ATLAS detector in proton-proton collisions at root s=7 TeV
The jet energy scale and its systematic uncertainty are determined for jets measured with the ATLAS detector at the LHC in proton-proton collision data at a centre-of-mass energy of √s = 7TeV corresponding to an integrated luminosity of 38 pb-1. Jets are reconstructed with the anti-kt algorithm with distance parameters R=0. 4 or R=0. 6. Jet energy and angle corrections are determined from Monte Carlo simulations to calibrate jets with transverse momenta pT≥20 GeV and pseudorapidities {pipe}η{pipe}<4. 5. The jet energy systematic uncertainty is estimated using the single isolated hadron response measured in situ and in test-beams, exploiting the transverse momentum balance between central and forward jets in events with dijet topologies and studying systematic variations in Monte Carlo simulations. The jet energy uncertainty is less than 2. 5 % in the central calorimeter region ({pipe}η{pipe}<0. 8) for jets with 60≤pT<800 GeV, and is maximally 14 % for pT<30 GeV in the most forward region 3. 2≤{pipe}η{pipe}<4. 5. The jet energy is validated for jet transverse momenta up to 1 TeV to the level of a few percent using several in situ techniques by comparing a well-known reference such as the recoiling photon pT, the sum of the transverse momenta of tracks associated to the jet, or a system of low-pT jets recoiling against a high-pT jet. More sophisticated jet calibration schemes are presented based on calorimeter cell energy density weighting or hadronic properties of jets, aiming for an improved jet energy resolution and a reduced flavour dependence of the jet response. The systematic uncertainty of the jet energy determined from a combination of in situ techniques is consistent with the one derived from single hadron response measurements over a wide kinematic range. The nominal corrections and uncertainties are derived for isolated jets in an inclusive sample of high-pT jets. Special cases such as event topologies with close-by jets, or selections of samples with an enhanced content of jets originating from light quarks, heavy quarks or gluons are also discussed and the corresponding uncertainties are determined. © 2013 CERN for the benefit of the ATLAS collaboration
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