Entropic fluctuations in XY chains and reflectionless Jacobi matrices

We study the entropic fluctuations of a general XY spin chain where initially the left(x0) part of the chain is in thermal equilibrium at inverse temperature Tl/Tr. The temperature differential results in a non-trivial energy/entropy flux across the chain. The Evans-Searles (ES) entropic functional describes fluctuations of the flux observable with respect to the initial state while the Gallavotti-Cohen (GC) functional describes these fluctuations with respect to the steady state (NESS) the chain reaches in the large time limit. We also consider the full counting statistics (FCS) of the energy/entropy flux associated to a repeated measurement protocol, the variational entropic functional (VAR) that arises as the quantization of the variational characterization of the classical Evans-Searles functional and a natural class of entropic functionals that interpolate between FCS and VAR. We compute these functionals in closed form in terms of the scattering data of the Jacobi matrix h canonically associated to the XY chain. We show that all these functionals are identical if and only if h is reflectionless (we call this phenomenon entropic identity). If h is not reflectionless, then the ES and GC functionals remain equal but differ from the FCS, VAR and interpolating functionals. Furthermore, in the non-reflectionless case, the ES/GC functional does not vanish at 1 (i.e., the Kawasaki identity fails) and does not have the celebrated ES/GC symmetry. The FCS, VAR and interpolating functionals always have this symmetry. In the cases where h is a Schr\"odinger operator, the entropic identity leads to some unexpected open problems in the spectral theory of one-dimensional discrete Schr\"odinger operators

Refinement of an Instrument to Assess Readiness for Knowledge Management

Academics and practitioners have described knowledge as a primary source for competitive advantage for organizations; however, many attempts at instituting knowledge management programs to increase organizational competitiveness do not succeed. Instituting knowledge management programs generally requires organizations to make significant changes and the concept of readiness has long been believed to be an important precondition for successful organizational change. By linking previous research in enablers for knowledge management and organizational change, it is possible to adapt an established organizational change readiness instrument to measure readiness for knowledge management. This study culminates in the development and field-testing of the resultant knowledge management readiness instrument, filling in an important gap in contemporary literature

The text of Jude 4

The article analyses three variation units and one singular reading from the text of Jude 4. Following the rationale of thoroughgoing eclecticism, it concentrates on internal evidence. The most problematic variation unit is δ∈oπóτην versus δ∈oπóτην  θ∈óν. Transcriptional arguments can be advanced in favour of either of these variants. To resolve the conflicting transcriptional evidence, an ‘etymological narrative’ is provided to establish the Attic and Judaeo-Hellenic background of the word δ∈oπóτην as a metaphor applicable to the gods or to God. The etymological narrative and other intrinsic arguments suggest that δ∈oπóτην refers to God, and that therefore an eclectic preference for the variant δ∈oπóτην  θ∈óν can be expressed

Jackpot! The Employment Effects of Gaming Revenue Allocation Plans on Native American Tribes

Revenue allocation plans (RAPs) are one way in which Native American tribal governments distribute their casino profits equally to every member of the tribe. This study matches tribes with approved RAPs to their respective “treatment” counties. These treatment counties are then matched and compared to control counties of similar geography and population through difference-in-difference analysis. Through this analysis, it is apparent that there are no effects of RAPs on unemployment rates in treatment counties – however, there seems to be a slight positive effect on employment-to-population ratios and labor force participation rates. This paper finds that the RAP in 22 counties (by proxy, tribes) studied do not follow the income effect. Instead, the study suggests that windfall (or non-labor) income on these tribes has a positive, yet small, effect on labor supply

IMPACT OF CONFORMATIONAL CHANGE, SOLVATION ENVIRONMENT, AND POST-TRANSLATIONAL MODIFICATION ON DESULFURIZATION ENZYME 2\u27-HYDROXYBIPHENYL-2-SULFINATE DESULFINASE (\u3cem\u3eDSZB\u3c/em\u3e) STABILITY AND ACTIVITY

Naturally occurring enzymatic pathways enable highly specific, rapid thiophenic sulfur cleavage occurring at ambient temperature and pressure, which may be harnessed for the desulfurization of petroleum-based fuel. One pathway found in bacteria is a four-step catabolic pathway (the 4S pathway) converting dibenzothiophene (DBT), a common crude oil contaminant, into 2-hydroxybiphenyl (HBP) without disrupting the carbon-carbon bonds. 2’-Hydroxybiphenyl-2-sulfinate desulfinase (DszB), the rate-limiting enzyme in the enzyme cascade, is capable of selectively cleaving carbon-sulfur bonds. Accordingly, understanding the molecular mechanisms of DszB activity may enable development of the cascade as industrial biotechnology. Based on crystallographic evidence, we hypothesized that DszB undergoes an active site conformational change associated with the catalytic mechanism. Moreover, we anticipated this conformational change is responsible, in part, for enhancing product inhibition. Rhodococcus erythropolis IGTS8 DszB was recombinantly produced in Escherichia coli BL21 and purified to test these hypotheses. Activity and the resulting conformational change of DszB in the presence of HBP were evaluated. The activity of recombinant DszB was comparable to the natively expressed enzyme and was competitively inhibited by the product, HBP. Using circular dichroism, global changes in DszB conformation were monitored in response to HBP concentration, which indicated that both product and substrate produced similar structural changes. Molecular dynamics (MD) simulations and free energy perturbation with Hamiltonian replica exchange molecular dynamics (FEP/λ-REMD) calculations were used to investigate the molecular-level phenomena underlying the connection between conformation change and kinetic inhibition. In addition to the HBP, MD simulations of DszB bound to common, yet structurally diverse, crude oil contaminates 2’2-biphenol (BIPH), 1,8-naphthosultam (NTAM), 2-biphenyl carboxylic acid (BCA), and 1,8-naphthosultone (NAPO) were performed. Analysis of the simulation trajectories, including root mean square fluctuation (RMSF), center of mass (COM) distances, and strength of nonbonded interactions, when compared with FEP/λ-REMD calculations of ligand binding free energy, showed excellent agreement with experimentally determined inhibition constants. Together, the results show that a combination of a molecule’s hydrophobicity and nonspecific interactions with nearby functional groups contribute to a competitively inhibitive mechanism that locks DszB in a closed conformation and precludes substrate access to the active site. Limitations in DszB’s potential applications in industrial sulfur fixation are not limited to turnover rate. To better characterize DszB stability and to gain insight into ways by which to extend lifetime, as well as to pave the way for future studies in inhibition regulation, we evaluated the basic thermal and kinetic stability of DszB in a variety of solvation environments. Thermal stability of DszB was measured in a wide range of different commercially available buffer additives using differential scanning fluorimetry (DSF) to quickly identify favorable changes in protein melting point. Additionally, a fluorescent kinetic assay was employed to investigate DszB reaction rate over a 48 hr time period in a more focused group of buffer to link thermal stability to DszB life-time. Results indicate a concerningly poor short-term stability of DszB, with an extreme preference for select osmolyte buffer additives that only moderately curbed this effect. This necessitates a means of stability improvement beyond alteration of solvation environment. To this end, a more general investigation of glycosylation and its impact on protein stability was performed. Post-translational modification of proteins occurs in organisms from all kingdoms life, with glycosylation being among the most prevalent of amendments. The types of glycans attached differ greatly by organism but can be generally described as protein-attached carbohydrate chains of variable lengths and degrees of branching. With great diversity in structure, glycosylation serves numerous biological functions, including signaling, recognition, folding, and stability. While it is understood that glycans fulfill a variety of important roles, structural and biochemical characterization of even common motifs and preferred rotamers is incomplete. To better understand glycan structure, particularly their relevance to protein stability, we modeled and computed the solvation free energy of 13 common N- and O-linked glycans in a variety of conformations using thermodynamic integration. N-linked glycans were modeled in the β-1,4-linked conformation, attached to an asparagine analog, while O-linked glycans were each modeled in both the α-1,4 and β-1,4-linked conformations attached to both serine and threonine analogs. Results indicate a strong preference for the β conformation and show a synergistic effect of branching on glycan solubility. Our results serve as a library of solvation free energies for fundamental glycan building blocks to enhance understanding of more complex protein-carbohydrate structures moving forward

What Women Want: a Study of Communication, Sex and Personality

Sexual communication is important in overall sexual and relationship satisfaction.Women, in particular, report lower psychological well-being when sexual dysfunction occurs (Davison, Bell, LaChina, Holden & Davis, 2009). This study was designed to uncover precisely how important sexual communication is in relation to sexual satisfaction, whether there are any discrepancies between women’s desired sexual acts verses the acts they actively take part in, and to what degree personality has an effect on sexual communication and activity. Participants were 428 women from the psychology pool at University of Central Florida. The average age of the sample was 20.7 years (SD = 5.24). Approximately 56% of the sample identified as white, 14% as black, 7% as Asian and 10% as other. Communication was positively correlated to sexual satis-faction, there were no found discrepancies between sexual participation and desired sexual acts among the study participants, and personality significantly predicted levels of communication and participation in varying sexual acts, particularly regarding extraversion, agreeableness and conscientiousness. Communication about sex is strongly related to life and health satisfaction and a greater understanding of sexual desires should be continually sought to create harmony within relationships

Deviational simulation of phonon transport in graphene ribbons with ab initio scattering

We present a deviational Monte Carlo method for solving the Boltzmann-Peierls equation with ab initio 3-phonon scattering, for temporally and spatially dependent thermal transport problems in arbitrary geometries. Phonon dispersion relations and transition rates for graphene are obtained from density functional theory calculations. The ab initio scattering operator is simulated by an energy-conserving stochastic algorithm embedded within a deviational, low-variance Monte Carlo formulation. The deviational formulation ensures that simulations are computationally feasible for arbitrarily small temperature differences, while the stochastic treatment of the scattering operator is both efficient and exhibits no timestep error. The proposed method, in which geometry and phonon-boundary scattering are explicitly treated, is extensively validated by comparison to analytical results, previous numerical solutions and experiments. It is subsequently used to generate solutions for heat transport in graphene ribbons of various geometries and evaluate the validity of some common approximations found in the literature. Our results show that modeling transport in long ribbons of finite width using the homogeneous Boltzmann equation and approximating phonon-boundary scattering using an additional homogeneous scattering rate introduces an error on the order of 10% at room temperature, with the maximum deviation reaching 30% in the middle of the transition regime.Singapore-MIT Alliance for Research and TechnologyAmerican Society for Engineering Education. National Defense Science and Engineering Graduate FellowshipNational Science Foundation (U.S.). Graduate Research Fellowshi

Anti-galectin-3 peptides increase apoptosis in galectin-3 expressing human breast cancer cells

Abstract only availableA critical factor in the proliferation and the metastatic nature of carcinoma cells appears to be their resistance to natural programmed cell death (apoptosis). However, the molecular mechanisms that enable carcinoma cells to become resistant to cell death are unclear. Galectin-3 (Gal-3) is a protein that is found at elevated levels in a variety of primary and metastatic tumor cells that may play a key role in chemo-resistance and proliferation of carcinoma cells. Gal-3 has also been found to play a key role in the regulation of common apoptosis commitment pathways. Therefore, we hypothesize that peptides, which bind to and inhibit Gal-3 functions, could be used to reduce the anti-apoptotic activity of Gal-3 thus increasing the occurrence of cell death in carcinoma cells. Two cell lines were cultured, the human breast cancer cell line BT549 and a Gal-3-transfected derivative of BT549 (BT549/V). After undergoing apoptosis induction with 0.5 M staurosporine, apoptosis markers were detected fluorescently using flow cytometry. Our preliminary data suggests that, in the absence of anti-galectin-3 peptides, the parent BT549 cell line exhibits mitochondrial damage (decrease in mitochondrial membrane potential as detected by using MitoTracker Red fluorescence) by 6 hours of staurosporine treatment, whereas the BT549/V cell line shows little change in MitoTracker Red fluorescence even after 8 hours of apoptosis induction. A similar pattern is observed when changes in MitoTracker Red fluorescence are correlated with changes in phosphatidylserine translocation from the inner to outer surface of the plasma membrane. The current data suggest that cells transfected with Gal-3 have an increased rate of survival after apoptosis induction. In the next phase of this ongoing project, flow cytometric studies of changes in membrane permeability and DNA damage in parent and galectin-3 transfected BT549 cells will be conducted to further define the time-dependent apoptotic response of the BT549 parent versus BT549/V cells. Finally, we will observe and compare the effect of anti-Gal-3 peptides on induction of apoptosis in these two cell lines in order to determine if Gal-3 plays a key role in the anti-apoptotic nature of carcinoma cells and to test if anti-Gal-3 peptides are efficacious in inhibiting the anti-apoptotic functions of Gal-3.Molecular Imaging Progra