Charm Production at Large Rapidities in p+p and d+Au Collisions at PHENIX at RHIC

We study charm production through dimuon and single muon measurements at forward and backward rapidities in p+p and d+Au collisions with the PHENIX muon detectors. We also compare open charm to $J/\psi$ yields in the forward and backward rapidities in d+Au collisions and study the origin of the large forward and backward asymmetry in open charm production observed by the PHENIX experiment.Comment: 4 pages, 3 figures, DIS2006 conference, April 2006, Tsukuba, Japa

Open Heavy Flavor Production in p+p, d+Au and Au+Au Collisions at (s)=200\sqrt(s)= 200 GeV

PHENIX results for open charm production from semi-lepton decay in p+p, d+Au and Au+Au collisions in a wide rapidity ranges at $\sqrt(s)= 200$ GeV are presented. Keywords: Relativistic Heavy-ion Collision, Open Charm production, Nuclear Medium Effect PACS: 25.75.-q, 25.75 Dw, 13.20.G

Heavy Flavor Production at PHENIX at RHIC

A study of heavy flavor production in different collision systems in various kinematic regions presents an opportunity to probe cold nuclear medium and hot dense matter effects. Results from the PHENIX experiment on $J/\psi$ and open charm production in Au+Au and Cu+Cu collisions at $\sqrt{s_{NN}}$ =200 GeV are presented. The data show strong $J/\psi$ suppression in central AA collisions, similar to NA50 results, and strong suppression in high $p_T$ open charm production. The $J/\psi$ production in Au+Au and d+Au collisions is compared to understand the cold nuclear medium effects. The data show significant cold nuclear effects in charm production in d+Au collisions at forward and backward rapidity ranges.Comment: 4 pages, 3figures, CIPANP2006, May 29-June 3, 2006. San Juan, PuertoRic

Learners’ Experiences of Written Complexities Development Through Discussion Board Activities in Chinese as a Foreign Language Class

This qualitative case study examines learners’ experiences in the development of written complexities during Discussion Board (DB) assignments in an Advanced university level Chinese class. Discussion Board was chosen as the avenue for written complexity development because it provides learners a supplementary space with additional time and opportunities for low anxiety writing. The data collection for this study came from two sources, DB posts and interviews. This study seeks to fill gap in the literature in two ways: one, this study proposes a measurement of written complexities that consists of propositional complexity, lexical sophistication and accuracy. Second, this study highlights student experiences and explores the learning process from their perspectives. Using Vygotsky’s (1978) Sociocultural theory as theoretical framework, the findings of this study generated new knowledge about what tools and strategies Chinese as a Foreign Language (CFL) learners used to develop written complexities during the DB discussion activities. Additionally, this study examined how CFL learners utilized DB activities and interactions on DB to develop written complexities. Finally, this study demonstrates how DB can serve as a supplementary learning space, where if designed appropriately, can lead to opportunities for students to develop their written complexities

How care demands, caregiving appraisal and coping affect self-care management of informal caregivers of persons with dementia.

BACKGROUND: Caring for a person with Alzheimer’s disease and related dementia (ADRD) is very stressful. Chronic stress which increases the risk for the development of disease and chronic illness is prevalent in caregivers of persons with ADRD. However, how caregiving affects self-care management of caregivers of persons with ADRD has not been well defined. PURPOSE: The purpose of this study is to examine relationships among care demands, caregiving appraisal, coping and caregiver self-care management and to investigate whether care demands, caregiving appraisal and coping are predictors of caregiver self-care management. METHODS: A cross-sectional study design was conducted among 45 primary informal caregivers of persons with ADRD in the southern part of the Midwest. Following an informed consent, paper-and-pencil questionnaires were administered for data collection. Quantitative data were analyzed with descriptive analysis, correlations, and multiple regressions, while responses to open-ended questions were analyzed using the principles of thematic analysis (Morse & Field, 1995). RESULTS: Three categories of predictors (caregiver demographic variables, care demands and active coping) uniquely explained caregiver self-care management. Care-recipients ADL/IADL dependency and duration of caregiving, reflecting care demands, explained the most variance for caregiver self-care, followed by caregiver demographic variables (education, female gender and financial status) and active coping. Total explained variance in each self-care activity was considerable, ranging from 37% to 57%. Our qualitative findings indicated that caregivers’ physical self-care and well-being were jeopardized given the needed care of care-recipients. In addition to self-care efforts by caregivers themselves, outside help and support as well as improved access to quality health care are essential to help caregivers improve health. CONCLUSIONS: Findings of this study help fill the gap in the literature by demonstrating the effects of caregiving on caregiver self-care management. This result is especially significant when viewed in conjunction with the high risk of chronic diseases among caregivers. Caregivers in poor health are more likely to stop caregiving. Interventions are imperative to help caregivers manage care-recipient’s needs so as to allow the needed time to the caregiver for essential medical treatment and follow-up as well as such health promotion activities as rest, sleep, relaxation, exercise, nutrition and socialization

Measurement of Open Heavy Flavor Production with Single Muons in p+p and d+Au Collisions at RHIC

Heavy flavor production in hadronic collisions is dominated by gluonic processes and so is a sensitive probe of the gluon structure function in the nucleon and its modification in nuclei. A study of heavy flavor production in p+p and d+Au collisions in various kinematic regions presents an opportunity to probe cold nuclear medium effects; parton shadowing, color glass condensate, initial state energy loss, and coherent multiple scattering in final state interactions. The PHENIX muon arms cover both forward and backward directions in the rapidity range of $1.2 < |\eta| < 2.4$. We investigate single muon production from open heavy flavor and light mesons decay in p+p and d+Au collisions at forward and backward rapidity.Comment: Strangeness in Quark Matter, 2006, UCL

Nonlinearity in Large Amplitude Oscillatory Shear (Laos) of Different Viscoelastic Materials

The present work investigates nonlinear behavior in large amplitude oscillatory shear (LAOS) of four different polymeric materials using simultaneous conventional rheometric measurements and particle-tracking velocimetric observations. In contrast to most studies in the literature that treat nonlinearity in LAOS in steady state, we emphasize by the present four examples that nonlinearity in LAOS often arise in complex fluids due to time-dependent rearrangement of their microstructures in response to LAOS. Consequently, no correlation is obvious between strain dependence of the steady-state stress response and the time-dependent characteristics of the steady-state response. For instance, a highly viscoelastic material made of nano-sized polybutadiene particles exhibits homogeneous deformation and an approximate sinusoidal wave despite strong strain softening. In a second example, a well-entangled polybutadiene solution becomes inhomogeneous over time, and the corresponding nonlinearity (i.e., strain softening) took a finite time to develop to its fullest. In the example of wall slip of a monodisperse entangled polyisoprene melt, contrary to the literature claim that even harmonics would emerge, we show that the stress response only involves odd harmonics in the absence of any edge fracture. Last, a polydisperse poly(dimethyl siloxane) melt experiences homogeneous LAOS without displaying significant higher harmonics in the absence of any edge failure. In contrast, the Fourier transform analysis shows that meniscus failure is responsible for the emergence of higher harmonics including some even ones. (C) 2009 The Society of Rheology. [DOI: 10.1122/1.3193713

Elastic Breakup in Uniaxial Extension of Entangled Polymer Melts

Five entangled melts, with the number of entanglements per chain ranging from 25 to 160, have been studied to illustrate how cohesive strength can be overcome in either continuous or interrupted extension (i.e., during or after uniaxial stretching). The internal elastic stress due to chain deformation from imposed strain appears to be the cause of the observed yielding behavior that reveals scaling laws. The visual signature of the elastic breakup is the occurrence of nonuniform extension. The yield phenomena may be understood at a force level