Covariation Among Vowel Height Effects on Acoustic Measures

Covariation among vowel height effects on vowel intrinsic fundamental frequency (IF0), voice onset time (VOT), and voiceless interval duration (VID) is analyzed to assess the plausibility of a common physiological mechanism underlying variation in these measures. Phrases spoken by 20 young adults, containing words composed of initial voiceless stops or /s/ and high or low vowels, were produced in habitual and voluntarily increased F0 conditions. High vowels were associated with increased IF0 and longer VIDs. VOT and VID exhibited significant covariation with IF0 only for males at habitua

Evidence for MBM_B and MCM_C phases in the morphotropic phase boundary region of (1−x)[Pb(Mg1/3Nb2/3)O3]−xPbTiO3(1-x)[Pb(Mg_{1/3}Nb_{2/3})O_3]-xPbTiO_3 : A Rietveld study

We present here the results of the room temperature dielectric constant measurements and Rietveld analysis of the powder x-ray diffraction data on $(1-x)[Pb(Mg_{1/3}Nb_{2/3})O_3]-xPbTiO_3$(PMN-$x$PT) in the composition range $0.20 \leq x \leq 0.45$ to show that the morphotropic phase boundary (MPB) region contains two monoclinic phases with space groups Cm (or $M_B$ type) and Pm (or $M_C$ type) stable in the composition ranges $0.27 \leq x \leq 0.30$ and $0.31 \leq x \leq 0.34$, respectively. The structure of PMN-$x$PT in the composition ranges $0 \leq x \leq$ 0.26, and $0.35 \leq x \leq1$ is found to be rhombohedral (R3m) and tetragonal (P4mm), respectively. These results are compared with the predictions of Vanderbilt & Cohen's theory.Comment: 20 pages, 11 pdf figure

Developing mathematical thinking in the primary classroom: liberating students and teachers as learners of mathematics

This paper reports on a research study conducted with a group of practising primary school teachers (n = 24) in North East Scotland during 2011–2012. The teachers were all participants in a newly developed Masters course that had been designed with the aim of promoting the development of mathematical thinking in the primary classroom as part of project supported by the Scottish Government. The paper presents the background for this initiative within the context of the Scottish Curriculum for Excellence reform. Particular attention is given to the epistemological positioning of the researchers as this influenced both the curriculum design process and also the theoretical framing of the research study which are both described. The project was set up within a design research framework, which aimed to promote classroom-based action research on the part of participants through the course and also research by the university researchers into the process of curriculum development. The research questions focused on the teachers’ confidence, competence, attitudes and beliefs in relation to mathematics and their expectations and experiences of the impact on pupil learning arising from this course. Empirical data were drawn from pre- and post-course surveys, interviews and observations of the discussion forums in the online environment. Findings from this study highlight the way the course had a transformational and emancipatory impact on these teachers. They also highlight ways in which the ‘framing’ of particular aspects of the curriculum had an oppressive impact on learners in the ways that suppressed creativity and limited the exercise of learner autonomy. Furthermore, they highlight the ways in which a number of these teachers had experienced mathematics as a school subject in very negative ways, involving high levels of ‘symbolic violence’ and of being ‘labelled’

Phase diagram of the ferroelectric-relaxor (1-x)PbMg(1/3)Nb(2/3)O3-xPbTiO3

Synchrotron x-ray powder diffraction measurements have been performed on unpoled ceramic samples of (1-x)PbMg(1/3)Nb(2/3)O3-xPbTiO3 (PMN-xPT) with 30%<= x<= 39% as a function of temperature around the morphotropic phase boundary (MPB), which is the line separating the rhombohedral and tetragonal phases in the phase diagram. The experiments have revealed very interesting features previously unknown in this or related systems. The sharp and well-defined diffraction profiles observed at high and intermediate temperatures in the cubic and tetragonal phases, respectively, are in contrast to the broad features encountered at low temperatures. These peculiar characteristics, which are associated with the monoclinic phase of MC-type previously reported by Kiat et al and Singh et al., can only be interpreted as multiple coexisting structures with MC as the major component. An analysis of the diffraction profiles has allowed us to properly characterize the PMN-xPT phase diagram and to determine the stability region of the monoclinic phase, which extends from x= 31% to x= 37% at 20 K. The complex lansdcape of observed phases points to an energy balance between the different PMN-xPT phases which is intrinsically much more delicate than that of related systems such as PbZr(1-x)TixO3 or (1-x)PbZn(1/3)Nb(1/3)O3-xPbTiO3. These observations are in good accord with an optical study of x= 33% by Xu et al., who observed monoclinic domains with several different polar directions coexisting with rhombohedral domains, in the same single crystal.Comment: REVTeX4, 11 pages, 10 figures embedde

Anomalous Thermal Transport in Quantum Wires

We study thermal transport in a one-dimensional quantum wire, connected to reservoirs. Despite of the absence of electron backscattering, interactions in the wire strongly influence thermal transport. Electrons propagate with unitary transmission through the wire and electric conductance is not affected. Energy, however, is carried by bosonic excitations (plasmons) which suffer from scattering even on scales much larger than the Fermi wavelength. If the electron density varies randomly, plasmons are localized and {\em charge-energy separation} occurs. We also discuss the effect of plasmon-plasmon interaction using Levinson's theory of nonlocal heat transport.Comment: replaced with published versio

Principles And Practices Fostering Inclusive Excellence: Lessons From The Howard Hughes Medical Institute’s Capstone Institutions

Best-practices pedagogy in science, technology, engineering, and mathematics (STEM) aims for inclusive excellence that fosters student persistence. This paper describes principles of inclusivity across 11 primarily undergraduate institutions designated as Capstone Awardees in Howard Hughes Medical Institute’s (HHMI) 2012 competition. The Capstones represent a range of institutional missions, student profiles, and geographical locations. Each successfully directed activities toward persistence of STEM students, especially those from traditionally underrepresented groups, through a set of common elements: mentoring programs to build community; research experiences to strengthen scientific skill/identity; attention to quantitative skills; and outreach/bridge programs to broaden the student pool. This paper grounds these program elements in learning theory, emphasizing their essential principles with examples of how they were implemented within institutional contexts. We also describe common assessment approaches that in many cases informed programming and created traction for stakeholder buy-in. The lessons learned from our shared experiences in pursuit of inclusive excellence, including the resources housed on our companion website, can inform others’ efforts to increase access to and persistence in STEM in higher education

Know Your Value: Negotiation Skill Development for Junior Investigators in the Academic Environment—A Report from the American Society of Preventive Oncology\u27s Junior Members Interest Group

The American Society of Preventive Oncology (ASPO) is a professional society for multidisciplinary investigators in cancer prevention and control. One of the aims of ASPO is to enable investigators at all levels to create new opportunities and maximize their success. One strategy adopted by ASPO was to develop the Junior Members Interest Group in 1999. The Interest Group membership includes predoctoral fellows, postdoctoral fellows, and junior faculty members who are provided career development and training opportunities (1). Responsibilities of the members of the Junior Members Interest Group include serving on the ASPO Executive Committee and the Program Planning Committee and organizing professional development sessions at ASPO\u27s annual meeting. As part of the 2014 ASPO annual meeting, the Junior Members Interest Group organized a session entitled “Negotiation Skill Development for Junior Investigators in the Academic Environment.” This interactive session was designed to provide early-career investigators an opportunity to practice their negotiation skills and to receive expert advice and strategies to effectively negotiate new faculty positions in an academic environment. The session focused primarily on negotiating an initial academic appointment from a graduate student or postdoctoral fellow to an assistant professor–level position. In addition to the main focus, the session also covered renegotiation for assistant and associate-level investigators as they navigate through their careers. The session began with an interactive exercise led by Dr. Stephanie A.N. Silvera (Associate Professor of Public Health, Montclair State University, Montclair, NJ) where participants engaged in a mock salary negotiation session with another member of the audience (Table 1). Following the negotiation exercise, Dr. Silvera led a debriefing session. Next, four panelists at different levels in their academic careers were invited to provide their personal perspectives on the topic of effective negotiation: Dr. Faith Fletcher (Assistant Professor of Community Health Sciences, the University of Illinois at Chicago, Chicago, IL) to provide the perspective of a first-year faculty member; Dr. Stephanie A.N. Silvera (Associate Professor of Public Health, Montclair State University, Montclair, NJ) to provide the perspective of a recently tenured faculty member; Dr. Karen Basen-Engquist (Professor of Behavioral Science and Director of the Center for Energy Balance, University of Texas MD Anderson Cancer Center, Houston, TX) to provide the perspective of a senior faculty member; and Dr. Peter G. Shields (Professor and Deputy Director of the Ohio State University Comprehensive Cancer Center, Columbus, OH) to provide the perspective of a senior faculty member with extensive experience on the employer side of an academic appointment negotiation. This report summarizes the main themes that emerged from the negotiation exercise debriefing, the speakers\u27 advice and recommendations, and responses to audience questions during the session

Measuring change in vulnerable adolescents: Findings from a peer education evaluation in South Africa

Introduction: In the context of poverty and HIV and AIDS, peer education is thought to be capable of providing vulnerable youth with psychosocial support as well as information and decision-making skills otherwise limited by scarce social and material resources. As a preventative education intervention method, peer education is a strategy aimed at norms and peer group influences that affect health behaviours and attitudes. However, too few evaluations of peer-led programmes are available,and they frequently fail to reflect real differences between those who have been recipients of peer education and those who have not. This article reports on an evaluation of a pilot peer-led intervention, entitled Vhutshilo, implemented on principles agreed upon through a collaborative effort in South Africa by the Harvard School of Public Health and the Centre for theSupport of Peer Education (the Rutanang collaboration). Vhutshilo targeted vulnerable adolescents aged 14–16 years living in some of South Africa’s under-resourced communities. Methodology: The research design was a mixed-method (qualitative and quantitative), longitudinal, quasi-experimental evaluation. Tools used included a quantitative survey questionnaire (n ¼ 183) and semi-structured interviews (n ¼ 32) with beneficiaries of peer education. Surveys were administered twice forbeneficiaries of peer education (n ¼ 73), immediately after completion of the programme (post-test) and 4 months later (delayed post-test), and once for control group members (n ¼ 110). The three main  methodological limitations in this study were the use of a once-off control group assessment as the baseline for comparison, without a pre-test, due to timing and resource constraints; a small sample size (n ¼ 183), which reduced the statistical power of the evaluation; and the unavailability of existing tested survey questions to measure the impact of peer education and its role in behaviour change. Findings: This article reports on the difficulties of designing a comprehensive evaluation within time and financial constraints, critically evaluates survey design with multi-item indicators, and discusses six statistically significant changes observed in Vhutshilo participants out of a 92-point survey. Youth struggling with poor quality education and living in economically fraught contexts with little social support, nonetheless, showed evidence of having greater knowledge of support networks and an expanded emotional repertoire by the end of the Vhutshilo programme, and 4 months later. At both individual and group level, many with low socio-economic status showed great improvement with regard to programme indicator scores. Conclusion: For the poorest adolescents, especially those living in the rural parts of South Africa, peer education has the potential to change future orientation, attitudes and knowledge regarding HIV and AIDS, including an intolerance for multiple concurrent partnerships. When well organised and properly supported, peer education programmes (and the Vhutshilo curriculum, in particular) provide vulnerable youth with opportunities to develop  psychosocial skills and informational resources that contribute to the changing of norms, attitudes and behaviours. However, the article also flags the need for effective peer education evaluations that take into account limited financial resources and that possess tested indicators of programme effectiveness

Development of Ferroelectric Order in Relaxor (1-x)Pb(Mg1/3Nb2/3)O3 - xPbTiO3

The microstructure and phase transition in relaxor ferroelectric Pb(Mg1/3Nb2/3)O3 (PMN) and its solid solution with PbTiO3 (PT), PMN-xPT, remain to be one of the most puzzling issues of solid state science. In the present work we have investigated the evolution of the phase symmetry in PMN-xPT ceramics as a function of temperature (20 K < T < 500 K) and composition (0 <= x <= 0.15) by means of high-resolution synchrotron x-ray diffraction. Structural analysis based on the experimental data reveals that the substitution of Ti^4+ for the complex B-site (Mg1/3Nb2/3)^4+ ions results in the development of a clean rhombohedral phase at a PT-concentration as low as 5%. The results provide some new insight into the development of the ferroelectric order in PMN-PT, which has been discussed in light of the kinetics of polar nanoregions and the physical models of the relaxor ferroelectrics to illustrate the structural evolution from a relaxor to a ferroelectric state.Comment: Revised version with updated references; 9 pages, 4 figures embedde