Condensate wave function and elementary excitations of bosonic polar molecules: beyond the first Born approximation

We investigate the condensate wave function and elementary excitations of strongly interacting bosonic polar molecules in a harmonic trap, treating the scattering amplitude beyond the standard first Born approximation (FBA). By using an appropriate trial wave function in the variational method, effects of the leading order correction beyond the FBA have been investigated and shown to be significantly enhanced when the system is close to the phase boundary of collapse. How such leading order effect of going beyond the FBA can be observed in a realistic experiment is also discussed.Comment: 7 pages, 4 figure

IsaB Inhibits Autophagic Flux to Promote Host Transmission of Methicillin-Resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a major nosocomial pathogen that is widespread in both health-care facilities and in the community at large, as a result of direct host-to-host transmission. Several virulence factors are associated with pathogen transmission to naive hosts. Immunodominant surface antigen B (IsaB) is a virulence factor that helps Staphylococcus aureus to evade the host defense system. However, the mechanism of IsaB on host transmissibility remains unclear. We found that IsaB expression was elevated in transmissible MRSA. Wild-type isaB strains inhibited autophagic flux to promote bacterial survival and elicit inflammation in THP-1 cells and mouse skin. MRSA isolates with increased IsaB expression showed decreased autophagic flux, and the MRSA isolate with the lowest IsaB expression showed increased autophagic flux. In addition, recombinant IsaB rescued the virulence of the isaB deletion strain and increased the group A streptococcus (GAS) virulence in vivo. Together, these results reveal that IsaB diminishes autophagic flux, thereby allowing MRSA to evade host degradation. These findings suggest that IsaB is a suitable target for preventing or treating MRSA infection

Andreev and Single Particle Tunneling Spectroscopies in Underdoped Cuprates

We study tunneling spectroscopy between a normal metal and underdoped cuprate superconductor modeled by a phenomenological theory in which the pseudogap is a precursor to the undoped Mott insulator. In the transparent tunneling limit, the spectra show a small energy gap associated with Andreev reflection. In the Giaever limit, the spectra show a large energy gap associated with single particle tunneling. Our theory semi-quantitatively describes the two gap behavior observed in tunneling experiments.Comment: 5 pages, 4 figures, submitted to Phys. Rev. Lett. minor changes of reference

PSYCHOMETRIC ANALYSES BASED ON EVIDENCE-CENTERED DESIGN AND COGNITIVE SCIENCE OF LEARNING TO EXPLORE STUDENTS' PROBLEM-SOLVING IN PHYSICS

Most analyses of physics assessment tests have been done within the framework of classical test theory in which only the number of correct answers is considered in the scoring. More sophisticated analyses have been developed recently by physics researchers to further study students' conceptions/misconceptions in physics learning to improve physics instruction. However, they are not connected with the well-developed psychometric machinery. The goal of this dissertation is to use a formal psychometric model to study students' conceptual understanding in physics (in particular, Newtonian mechanics). The perspective is based on the evidence-centered design (ECD) framework, building on previous analyses of the cognitive processes of physics problem-solving and the task design from two physics tests (Force Concept Inventory, FCI and Force Motion Concept Evaluation, FMCE) that are commonly used to measure students' conceptual understanding about force-motion relationships. Within the ECD framework, the little-known Andersen/Rasch (AR) multivariate IRT model that can deal with mixtures of strategies within individuals is then introduced and discussed, including the issue of identification of the model. To demonstrate its usefulness, four data sets (one from FCI and three from FMCE) were used and analyzed with the AR model using a Markov Chain Monte Carlo estimation procedure, carried out with the BUGS computer program. Results from the first three data sets (questions were used to assess students' understanding about force-motion relationships) indicate that most students are in a mixed model state (i.e., in a transition toward understanding Newtonian mechanics) after one semester of physics learning. In particular, they incorrectly tend to believe that there must be a force acting on an object to maintain its movement, one of the common misconceptions indicated in physics literature. Findings from the last data set (which deals with acceleration) indicate that although students have improved their understanding about acceleration after one semester of instruction, they may still find it difficult to represent their understanding in terms of acceleration-time graphs. This is especially so when the object is slowing down or moving toward the left, in which case the sign of acceleration in both task scenarios is negative

Catastrophic Emission of Charges from Near-Extremal Nariai Black Holes

Using the in-out formalism and also the monodromy method, we study the emission of charges from near-extremal charged Nariai black holes with the black hole and cosmological horizons close to each other. The emission becomes catastrophic for a charge with energy greater than its chemical potential, whose leading exponential factor increases inversely proportional to the separation of two horizons. This implies that near-extremal Nariai black holes quickly evaporate through the charge emission and end in the de Sitter space, in contrast to near-extremal RN-dS black holes that have the Breitenlohner-Friedman bound below which they become stable against Hawking radiation and Schwinger effect of charge emission. We illuminate the origin of the catastrophic emission in the phase-integral formulation by comparing near-extremal charged Nariai black holes with near-extremal RN-dS black holes.Comment: 15 page

An Integrated Web-based System for MEDLINE Analysis: A Case Study of Chronic Kidney Disease

In the era of big data, medical researchers attempt to utilize some analysis techniques like machine learning and text mining on their large-scale corpora to save valuable labor work and time. Consequently, many data analysis platforms are built to support medical professionals such as Pubtator, GeneWays, BioContext, etc. These platforms are helpful to medical entities recognition and relation extraction, but there is not an integrated platform to support researchers’ various needs, and medical projects are isolated from each other, which is hard to be shared and reused. As a result, we present an integrated system containing ‘name entity recognition’, ‘document categorization’ and ‘association extraction’. Besides, we add the concept of ‘socialization’ making projects reusable for further analyses. A case study of chronic kidney disease was adopted to indicate the effectiveness of the proposed system