1,084 research outputs found

    I was Called ā€œAggressiveā€ in a Classroom:ā€ How Educator Preparation Programs Can Better Prepare Students for Diversity

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    The paper is an account of an Afro-Caribbean, female Ph.D. candidate being called Aggressive while teaching at a predominately White institution (PWI) in the Midwest. The recollection of the experience explores, through the eyes of a Black female scholar, the emotions of being called Aggressive on a PWI campus and highlights the work that remains in helping develop future educators who are not threatened by ethnic and cultural diversity in the classroom

    Evaluating the perceptions of pre-service teachers' personal and professional readiness to teach culturally and linguistically diverse students

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    This study examines preservice teachers from Historically Black Colleges and Universities and non-Historically Black Colleges and Universities and their perceptions of being personal and professional ready to teach culturally and linguistically diverse students with and without disabilities. Their exposure to the three characteristics of "teacher preparation for diversity" (Akiba, 2011) is also examined. Ninety-two preservice teachers from HBCUs and non-HBCUs across the United States completed a questionnaire about their experiences and perceptions of professional and personal readiness to teach culturally and linguistically diverse students. Quantitative results showed that diverse field experiences, instructor modeling culturally responsive practices and town size were significant predictors of professional and personal readiness to teach culturally diverse students. Implications for teacher preparation programs and future research are discussed.Includes bibliographical references

    Mitochondrial DNA Variant Discovery and Evaluation in Human Cardiomyopathies through Next-Generation Sequencing

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    Mutations in mitochondrial DNA (mtDNA) may cause maternally-inherited cardiomyopathy and heart failure. In homoplasmy all mtDNA copies contain the mutation. In heteroplasmy there is a mixture of normal and mutant copies of mtDNA. The clinical phenotype of an affected individual depends on the type of genetic defect and the ratios of mutant and normal mtDNA in affected tissues. We aimed at determining the sensitivity of next-generation sequencing compared to Sanger sequencing for mutation detection in patients with mitochondrial cardiomyopathy. We studied 18 patients with mitochondrial cardiomyopathy and two with suspected mitochondrial disease. We ā€œshotgunā€ sequenced PCR-amplified mtDNA and multiplexed using a single run on Roche's 454 Genome Sequencer. By mapping to the reference sequence, we obtained 1,300Ɨ average coverage per case and identified high-confidence variants. By comparing these to >400 mtDNA substitution variants detected by Sanger, we found 98% concordance in variant detection. Simulation studies showed that >95% of the homoplasmic variants were detected at a minimum sequence coverage of 20Ɨ while heteroplasmic variants required >200Ɨ coverage. Several Sanger ā€œmissesā€ were detected by 454 sequencing. These included the novel heteroplasmic 7501T>C in tRNA serine 1 in a patient with sudden cardiac death. These results support a potential role of next-generation sequencing in the discovery of novel mtDNA variants with heteroplasmy below the level reliably detected with Sanger sequencing. We hope that this will assist in the identification of mtDNA mutations and key genetic determinants for cardiomyopathy and mitochondrial disease

    Search for direct pair production of the top squark in all-hadronic final states in proton-proton collisions at sāˆš=8 TeV with the ATLAS detector

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    The results of a search for direct pair production of the scalar partner to the top quark using an integrated luminosity of 20.1fbāˆ’1 of protonā€“proton collision data at āˆšs = 8 TeV recorded with the ATLAS detector at the LHC are reported. The top squark is assumed to decay via tĖœā†’tĻ‡Ėœ01 or tĖœā†’ bĻ‡ĖœĀ±1 ā†’bW(āˆ—)Ļ‡Ėœ01 , where Ļ‡Ėœ01 (Ļ‡ĖœĀ±1 ) denotes the lightest neutralino (chargino) in supersymmetric models. The search targets a fully-hadronic final state in events with four or more jets and large missing transverse momentum. No significant excess over the Standard Model background prediction is observed, and exclusion limits are reported in terms of the top squark and neutralino masses and as a function of the branching fraction of tĖœ ā†’ tĻ‡Ėœ01 . For a branching fraction of 100%, top squark masses in the range 270ā€“645 GeV are excluded for Ļ‡Ėœ01 masses below 30 GeV. For a branching fraction of 50% to either tĖœ ā†’ tĻ‡Ėœ01 or tĖœ ā†’ bĻ‡ĖœĀ±1 , and assuming the Ļ‡ĖœĀ±1 mass to be twice the Ļ‡Ėœ01 mass, top squark masses in the range 250ā€“550 GeV are excluded for Ļ‡Ėœ01 masses below 60 GeV

    Measurement of the cross-section of high transverse momentum vector bosons reconstructed as single jets and studies of jet substructure in pp collisions at āˆšs = 7 TeV with the ATLAS detector

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    This paper presents a measurement of the cross-section for high transverse momentum W and Z bosons produced in pp collisions and decaying to all-hadronic final states. The data used in the analysis were recorded by the ATLAS detector at the CERN Large Hadron Collider at a centre-of-mass energy of āˆšs = 7 TeV;{\rm Te}{\rm V}andcorrespondtoanintegratedluminosityof and correspond to an integrated luminosity of 4.6\;{\rm f}{{{\rm b}}^{-1}}.ThemeasurementisperformedbyreconstructingtheboostedWorZbosonsinsinglejets.ThereconstructedjetmassisusedtoidentifytheWandZbosons,andajetsubstructuremethodbasedonenergyclusterinformationinthejetcentreāˆ’ofāˆ’massframeisusedtosuppressthelargemultiāˆ’jetbackground.Thecrossāˆ’sectionforeventswithahadronicallydecayingWorZboson,withtransversemomentum. The measurement is performed by reconstructing the boosted W or Z bosons in single jets. The reconstructed jet mass is used to identify the W and Z bosons, and a jet substructure method based on energy cluster information in the jet centre-of-mass frame is used to suppress the large multi-jet background. The cross-section for events with a hadronically decaying W or Z boson, with transverse momentum {{p}_{{\rm T}}}\gt 320\;{\rm Ge}{\rm V}andpseudorapidity and pseudorapidity |\eta |\lt 1.9,ismeasuredtobe, is measured to be {{\sigma }_{W+Z}}=8.5\pm 1.7$ pb and is compared to next-to-leading-order calculations. The selected events are further used to study jet grooming techniques

    Search for pair-produced long-lived neutral particles decaying to jets in the ATLAS hadronic calorimeter in ppcollisions at āˆšs=8TeV

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    The ATLAS detector at the Large Hadron Collider at CERN is used to search for the decay of a scalar boson to a pair of long-lived particles, neutral under the Standard Model gauge group, in 20.3fbāˆ’1of data collected in protonā€“proton collisions at āˆšs=8TeV. This search is sensitive to long-lived particles that decay to Standard Model particles producing jets at the outer edge of the ATLAS electromagnetic calorimeter or inside the hadronic calorimeter. No significant excess of events is observed. Limits are reported on the product of the scalar boson production cross section times branching ratio into long-lived neutral particles as a function of the proper lifetime of the particles. Limits are reported for boson masses from 100 GeVto 900 GeV, and a long-lived neutral particle mass from 10 GeVto 150 GeV

    Measurement of the production of a W boson in association with a charm quark in pp collisions at āˆšs = 7 TeV with the ATLAS detector

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    The production of a W boson in association with a single charm quark is studied using 4.6 fbāˆ’1 of pp collision data at sāˆš = 7 TeV collected with the ATLAS detector at the Large Hadron Collider. In events in which a W boson decays to an electron or muon, the charm quark is tagged either by its semileptonic decay to a muon or by the presence of a charmed meson. The integrated and differential cross sections as a function of the pseudorapidity of the lepton from the W-boson decay are measured. Results are compared to the predictions of next-to-leading-order QCD calculations obtained from various parton distribution function parameterisations. The ratio of the strange-to-down sea-quark distributions is determined to be 0.96+0.26āˆ’0.30 at Q 2 = 1.9 GeV2, which supports the hypothesis of an SU(3)-symmetric composition of the light-quark sea. Additionally, the cross-section ratio Ļƒ(W + +cĀÆĀÆ)/Ļƒ(W āˆ’ + c) is compared to the predictions obtained using parton distribution function parameterisations with different assumptions about the sāˆ’sĀÆĀÆĀÆ quark asymmetry

    Evidence for the Higgs-boson Yukawa coupling to tau leptons with the ATLAS detector

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    Results of a search for H ā†’ Ļ„ Ļ„ decays are presented, based on the full set of proton-proton collision data recorded by the ATLAS experiment at the LHC during 2011 and 2012. The data correspond to integrated luminosities of 4.5 fbāˆ’1 and 20.3 fbāˆ’1 at centre-of-mass energies of āˆšs = 7 TeV and āˆšs = 8 TeV respectively. All combinations of leptonic (Ļ„ ā†’ `Ī½Ī½ĀÆ with ` = e, Āµ) and hadronic (Ļ„ ā†’ hadrons Ī½) tau decays are considered. An excess of events over the expected background from other Standard Model processes is found with an observed (expected) significance of 4.5 (3.4) standard deviations. This excess provides evidence for the direct coupling of the recently discovered Higgs boson to fermions. The measured signal strength, normalised to the Standard Model expectation, of Āµ = 1.43 +0.43 āˆ’0.37 is consistent with the predicted Yukawa coupling strength in the Standard Model

    Measurements of fiducial and differential cross sections for Higgs boson production in the diphoton decay channel at sāˆš=8 TeV with ATLAS

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    Measurements of fiducial and differential cross sections are presented for Higgs boson production in proton-proton collisions at a centre-of-mass energy of sāˆš=8 TeV. The analysis is performed in the H ā†’ Ī³Ī³ decay channel using 20.3 fbāˆ’1 of data recorded by the ATLAS experiment at the CERN Large Hadron Collider. The signal is extracted using a fit to the diphoton invariant mass spectrum assuming that the width of the resonance is much smaller than the experimental resolution. The signal yields are corrected for the effects of detector inefficiency and resolution. The pp ā†’ H ā†’ Ī³Ī³ fiducial cross section is measured to be 43.2 Ā±9.4(stat.) āˆ’ā€‰2.9 +ā€‰3.2 (syst.) Ā±1.2(lumi)fb for a Higgs boson of mass 125.4GeV decaying to two isolated photons that have transverse momentum greater than 35% and 25% of the diphoton invariant mass and each with absolute pseudorapidity less than 2.37. Four additional fiducial cross sections and two cross-section limits are presented in phase space regions that test the theoretical modelling of different Higgs boson production mechanisms, or are sensitive to physics beyond the Standard Model. Differential cross sections are also presented, as a function of variables related to the diphoton kinematics and the jet activity produced in the Higgs boson events. The observed spectra are statistically limited but broadly in line with the theoretical expectations
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