Collective Modes and Raman Scattering in One Dimensional Electron Systems

In this paper, we review recent development in the theory of resonant inelastic light (Raman) scattering in one-dimensional electron systems. The particular systems we have in mind are electron doped GaAs based semiconductor quantum wire nanostructures, although the theory can be easily modified to apply to other one-dimensional systems. We compare the traditional conduction-band-based non-resonant theories with the full resonant theories including the effects of interband transitions. We find that resonance is essential in explaining the experimental data in which the single particle excitations have finite spectral weights comparable to the collective charge density excitations. Using several different theoretical models (Fermi liquid model, Luttinger liquid model, and Hubbard model) and reasonable approximations, we further demonstrate that the ubiquitously observed strong single particle excitations in the experimental Raman spectra cannot be explained by the spinless multi-spinon excitations in the Luttinger liquid description. The observability of distinct Luttinger liquid features in the Raman scattering spectroscopy is critically discussed.Comment: A review to be published in the special issue of Solid State Communications on one-dimensional system

The Benefits of Peer-Lead Mock Focused Exam Workshops

Context: Mock examinations are commonplace in many academic settings and are offered as a study aid to students with the hope of lowering stress levels and increasing their preparedness for the actual exam. In contrast, mock exams are rarely offered by faculty in clinical training due to their expense and administrative burden (1). Students taking objective structured clinical examinations, (OSCEs), have been proven to benefit from participating in mock exams (2). However, this is something that has not been explored in the context of the Focused Exam Workshop (FEW). While OSCEs focus solely on biomechanical skills, the FEW allows students to choose which physical exams are important for gathering information pertinent to creating a diagnosis and writing a SOAP note. In this study, we assess the efficacy of providing first year medical students with a mock exam prior to taking their FEW. This will stress the importance of implementing peer-organized mock examinations. Objective: Our study objective is to draw correlations between mock Focused Exam Workshop participation and overall performance on the course examination including final score, student stress levels, and biomechanical performance. This study will create a fundamental basis for understanding the effectiveness of participating in mock exams as preparation for all physical and clinically based skill examinations. Methods: The students were offered a SOAP note workshop and provided with complete exams specific to PCOM-GA curriculum as preparatory work prior to testing. Mock exams were then performed virtually with second year students acting as standardized patients (SP) with prepared case presentations. Thirty first year students acting as the doctor were asked to join the virtual rooms at different times and then perform a History and Physical with their SP focusing around a specific chief complaint that the students were unaware of before beginning the exam. Instructions were given on how the mock exam process will be conducted but no other hints were given to students regarding the context of the exam. Following the history and physical exam, the students were asked to create a SOAP note within the 9 minute limit offered by the COMLEX Level 2 PE exam (3). These SOAP notes were graded based on course description and COMLEX Level - 2 PE guideline by the student’s respective SP before the data was compiled. We also asked students to provide us with feedback through a Google Form that was sent out after the actual FEW was completed, so that they could provide us with extra information regarding their state of mind and chief complaint preferences among other things. All of this data was compiled and analyzed before being compared to student’s actual FEW scores which were provided to us without any identifying information, as to preserve student anonymity. IRB approval was obtained through the committee at the Philadelphia College of Osteopathic Medicine Georgia Campus. Results & Conclusions: Results are pending further stud

Dynamics of Davydov Ansatze

Following the Dirac-Frenkel time-dependent variational principle, dynamics of a one-dimensional Holstein polaron is probed by employing the Davydov D2 Ansatz with two sets of variational parameters, one for each constituting particle in the exciton-phonon system, and a simplified variant of the Davydov D1 Ansatz, also known as the $\tilde{D}$ Ansatz, with an additional set of phonon displacement parameters. A close examination of variational outputs from the two trial states reveals fine details of the polaron structure and intricacies of dynamic exciton-phonon interactions. Superradiance coherence sizes, speeds of exciton-induced phonon wave packets, linear optical absorption, and polaron energy compositions are also included in the study.Comment: 14 pages and 11 figue

Towards Plasma-Driven Free-Electron Lasers

Plasma-based accelerators are promising candidates to drive next-generation compact freeelectronlasers (FEL) with unique X-ray properties. The correct modelling of the physics in thelaser-plasma accelerator and of the FEL amplification from plasma-generated electron bunchesthereby forms the basis for any application driven by these beams. Both problems are, however,extremely challenging. They heavily rely on computer simulations and, in fact, act as sciencedrivers for the development of the latest generation of high-performance, highly parallel andefficient simulation codes. Here, we present our work towards a plasma-driven FEL, based onthe particle-in-cell (PIC) codes VSIM and WARP, and the non-averaging 3D FEL code PUFFIN

Assessing the Obstetric Patient’s Knowledge of Pregnancy

Purpose: Anecdotal evidence suggests a majority of patients in our urban, county hospital setting are lacking in their knowledge and understanding of pregnancy. Tarrant County has an increasing infant mortality rate which is higher than state and national rates. Currently, there is no consensus regarding what minimal basic knowledge obstetrical patients are encouraged to know regarding pregnancy. Centering pregnancy is a new model of antenatal care that integrates health assessment, education, and support through group-based meetings and facilitated discussions. This setting may be more conducive to patient education than traditional prenatal care. A survey was designed in attempt to assess and establish a baseline of our obstetric patient population’s level of knowledge regarding pregnancy. Methods: A questionnaire was developed to collect patient demographic information and assess basic knowledge. The knowledge-based questions were designed based on patient education materials available from ACOG and a consensus of providers from our department. The questions focused on modifiable maternal risks factors found to have the highest correlation to infant mortality in Tarrant County. Questions assessing knowledge utilized a Likert scale response. Patients self-reported whether they received traditional, Centering Pregnancy, or no prenatal care. Univariate statistical analysis was performed on the demographic information. For analysis of the knowledge-based questions, a score was given based on the sum of items correctly responded. Results: From July to August 2014, 150 surveys were completed by patients on their first postpartum day. 6.5% reported they did not receive any prenatal care and the remaining respondents received care from a physician, nurse practitioner, or midwife. 24% of those who received prenatal care attended Centering Pregnancy. 44% reported they learned most of their pregnancy information from family and friends versus 36% from a clinical provider. 45% were high school graduates. For the knowledge based questions, 46.9% of the respondents answered 80% of the questions correctly. The average score for the entire sample was 72.9% correct. Respondents who received traditional care had a score of 73.5% correct versus Centering Pregnancy with 70% correct. Respondents scored higher on questions regarding health and social behavior questions such as diabetes, hypertension, smoking, and drug use, compared to questions pertaining to the postpartum period or self-perception. Conclusions: Information concluded from the study allows providers to better understand our current patient population’s basic knowledge of pregnancy. There appears to be a better recognition of health and social risks factors affecting pregnancy such as smoking, drug use, diabetes, and hypertension. Deficits in knowledge, such as aspects regarding the postpartum period, were better identified, which will allow providers to tailor their antepartum and postpartum patient education. Providers do need to recognize that patients heavily rely on family members for pregnancy information. Though the patients who received Centering Pregnancy received a slightly overall lower knowledge score, as the sample size of patients who received Centering Pregnancy was small, a direct correlation cannot be drawn. The average knowledge score of 72.9% correct offers a baseline standard on to which we can assess for improvements in patient education in future studies. In improving basic patient knowledge and affecting modifiable risk factors, providers can potentially impact the infant mortality rate

The Mediator Complex: A Regulatory Hub for Transcriptional Activity of Nuclear Receptors

The Mediator complex plays a key role in gene transcription. In particular, the interaction of the Mediator complex with nuclear receptors, the known transcription factors, regulates multiple nuclear receptor-mediated gene transcription pathways and associated cellular functions. Dysregulation of the interaction of the Mediator complex with nuclear receptors results in many pathological processes, such as cancer, metabolic and neuronal diseases. Thus, understanding of the mechanism by which the Mediator complex regulates the nuclear receptor-mediated transcriptional activity and biological function is crucial for therapy of both the Mediator complex- and nuclear receptor-associated diseases. In this review article, we attempt to summarize current research progress in the interaction of the Mediator complex with nuclear receptors and the associated nuclear receptor transcriptional signaling pathways, explore the clinical potential of the Mediator complex as a therapeutic target, and provide new perspectives for the treatment of diseases associated with the Mediator complex and nuclear receptors