Giant Anharmonic Phonon Scattering in PbTe

Understanding the microscopic processes affecting the bulk thermal conductivity is crucial to develop more efficient thermoelectric materials. PbTe is currently one of the leading thermoelectric materials, largely thanks to its low thermal conductivity. However, the origin of this low thermal conductivity in a simple rocksalt structure has so far been elusive. Using a combination of inelastic neutron scattering measurements and first-principles computations of the phonons, we identify a strong anharmonic coupling between the ferroelectric transverse optic (TO) mode and the longitudinal acoustic (LA) modes in PbTe. This interaction extends over a large portion of reciprocal space, and directly affects the heat-carrying LA phonons. The LA-TO anharmonic coupling is likely to play a central role in explaining the low thermal conductivity of PbTe. The present results provide a microscopic picture of why many good thermoelectric materials are found near a lattice instability of the ferroelectric type

Sorteio intradomiciliar em inquéritos de saúde

OBJETIVO : Comparar a eficiência e a acurácia de delineamentos de amostragem com e sem sorteio intradomiciliar em inquéritos de saúde. MÉTODOS : Com base nos dados de um inquérito realizado na Baixada Santista, SP, entre 2006 e 2007, foram retiradas 1.000 amostras sob cada um dos delineamentos e, em cada amostra, foram obtidas estimativas para pessoas de 18 a 59 anos de idade e de 18 anos e mais. Sob o primeiro, foram sorteados 40 setores censitários, 12 domicílios por setor e uma pessoa por domicílio. Na análise, os dados foram ponderados pelo número de adultos residentes nos domicílios. Sob o segundo, foram sorteados 40 setores, seis domicílios por setor para o grupo de 18 a 59 anos de idade e cinco ou seis domicílios para o grupo de 18 anos e mais. Não houve sorteio dentro do domicílio. Medidas de precisão e de vício das estimativas de proporção para 11 indicadores foram calculadas nos dois conjuntos finais das amostras selecionadas para os dois tipos de delineamentos. Estes foram comparados por meio das medidas relativas: coeficiente de variação, razão vício/média, razão vício/erro padrão e erro quadrático médio relativo. O custo foi comparado considerando custo básico por pessoa, custo por domicílio e números de pessoas e domicílios. RESULTADOS : Os vícios mostraram-se desprezíveis nos dois delineamentos. A precisão foi maior para o delineamento sem sorteio e o custo foi menor. CONCLUSÕES : O delineamento sem sorteio intradomicilar mostrou-se superior em termos de eficiência e acurácia, devendo ser a opção preferencial do pesquisador. O sorteio de moradores deve ser adotado quando houver razões referentes ao objeto de estudo que possam levar à introdução de vícios nas respostas dos entrevistados no caso de vários moradores responderem ao questionário proposto

Urban schools' teachers enacting project-based science

What teaching practices foster inquiry and promote students to learn challenging subject matter in urban schools? Inquiry-based instruction and successful inquiry learning and teaching in project-based science (PBS) were described in previous studies (Brown & Campione, 1990 ; Crawford, 1999 ; Krajcik, Blumenfeld, Marx, Bass, & Fredricks, 1998 ; Krajcik, Blumenfeld, Marx, & Solloway, 1994 ; Minstrell & van Zee, 2000 ). In this article, we describe the characteristics of inquiry teaching practices that promote student learning in urban schools. Teaching is a major factor that affects both achievement of and attitude of students toward science (Tamir, 1998 ). Our involvement in reform in a large urban district includes the development of suitable learning materials and providing continuous and practiced-based professional development (Fishman & Davis, in press; van Es, Reiser, Matese, & Gomez, 2002 ). Urban schools face particular challenges when enacting inquiry-based teaching practices like those espoused in PBS. In this article, we describe two case studies of urban teachers whose students achieved high gains on pre- and posttests and who demonstrated a great deal of preparedness and commitment to their students. Teachers' attempts to help their students to perform well are described and analyzed. The teachers we discuss work in a school district that strives to bring about reform in mathematics and science through systemic reform. The Center for Learning Technologies in Urban Schools (LeTUS) collaborates with the Detroit Public Schools to bring about reform in middle-school science. Through this collaboration, diverse populations of urban-school students learn science through inquiry-oriented projects and the use of various educational learning technologies. For inquiry-based science to succeed in urban schools, teachers must play an important role in enacting the curriculum while addressing the unique needs of students. The aim of this article is to describe patterns of good science teaching in urban school. © 2006 Wiley Periodicals, Inc. J Res Sci Teach 43: 722–745, 2006Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/55780/1/20102_ftp.pd

X-Ray Repair Cross-Complementing Group 1 (XRCC1) Genetic Polymorphisms and Risk of Childhood Acute Lymphoblastic Leukemia: A Meta-Analysis

Background: Recently, there have been a number of studies on the association between XRCC1 polymorphisms and childhood acute lymphoblastic leukemia (ALL) risk. However, the results of previous reports are inconsistent. Thus, we performed a meta-analysis to clarify the effects of XRCC1 variants on childhood ALL risk. Methods: A meta-analysis was performed to examine the association between XRCC1 polymorphisms (Arg399Gln, Arg194Trp, and Arg280His) and childhood ALL risk. We critically reviewed 7 studies with a total of 880 cases and 1311 controls for Arg399Gln polymorphism, 3 studies with a total of 345 cases and 554 controls for Arg280His polymorphism, and 6 studies with a total of 783 cases and 1180 controls for Arg194Trp polymorphism, respectively. Odds ratio (OR) and its 95% confidence interval (CI) were used. Results: Significant association between XRCC1 Arg399Gln polymorphism and childhood ALL risk was observed in total population analyses (OR additive model = 1.501, 95 % CI 1.112–2.026, P OR = 0.008; OR dominant model = 1.316, 95 % CI = 1.104–1.569, POR = 0.002) and Asian subgroup analyses (ORadditive model = 2.338, 95%CI = 1.254–4.359, POR = 0.008; ORdominant model = 2.108, 95%CI = 1.498–2.967, POR = 0.000). No association was detected in Caucasians, Metizo and mixed populations. Ethnicity was considered as a significant source of heterogeneity in the meta-regression model. For the other two XRCC1 polymorphisms, no association with childhood ALL risk was found

Study protocol: cross-national comparative case study of recovery-focused mental health care planning and coordination (COCAPP).

BACKGROUND: The collaborative care planning study (COCAPP) is a cross-national comparative study of care planning and coordination in community mental healthcare settings. The context and delivery of mental health care is diverging between the countries of England and Wales whilst retaining points of common interest, hence providing a rich geographical comparison for research. Across England the key vehicle for the provision of recovery-focused, personalised, collaborative mental health care is the care programme approach (CPA). The CPA is a form of case management introduced in England in 1991, then revised in 2008. In Wales the CPA was introduced in 2003 but has now been superseded by The Mental Health (Care Co-ordination and Care and Treatment Planning) (CTP) Regulations (Mental Health Measure), a new statutory framework. In both countries, the CPA/CTP requires providers to: comprehensively assess health/social care needs and risks; develop a written care plan (which may incorporate risk assessments, crisis and contingency plans, advanced directives, relapse prevention plans, etc.) in collaboration with the service user and carer(s); allocate a care coordinator; and regularly review care. The overarching aim of this study is to identify and describe the factors that ensure CPA/CTP care planning and coordination is personalised, recovery-focused and conducted collaboratively. METHODS/DESIGN: COCAPP will employ a concurrent transformative mixed methods approach with embedded case studies. Phase 1 (Macro-level) will consider the national context through a meta-narrative mapping (MNM) review of national policies and the relevant research literature. Phase 2 (Meso-level and Micro-level) will include in-depth micro-level case studies of everyday 'frontline' practice and experience with detailed qualitative data from interviews and reviews of individual care plans. This will be nested within larger meso-level survey datasets, senior-level interviews and policy reviews in order to provide potential explanations and understanding. DISCUSSION: COCAPP will help identify the key components that support and hinder the provision of personalised, recovery-focused care planning and provide an informed rationale for a future planned intervention and evaluation

Search for high-mass resonances decaying to dilepton final states in pp collisions at s√=7 TeV with the ATLAS detector

The ATLAS detector at the Large Hadron Collider is used to search for high-mass resonances decaying to an electron-positron pair or a muon-antimuon pair. The search is sensitive to heavy neutral Z′ gauge bosons, Randall-Sundrum gravitons, Z * bosons, techni-mesons, Kaluza-Klein Z/γ bosons, and bosons predicted by Torsion models. Results are presented based on an analysis of pp collisions at a center-of-mass energy of 7 TeV corresponding to an integrated luminosity of 4.9 fb−1 in the e + e − channel and 5.0 fb−1 in the μ + μ −channel. A Z ′ boson with Standard Model-like couplings is excluded at 95 % confidence level for masses below 2.22 TeV. A Randall-Sundrum graviton with coupling k/MPl=0.1 is excluded at 95 % confidence level for masses below 2.16 TeV. Limits on the other models are also presented, including Technicolor and Minimal Z′ Models

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