Systematic reduction of sign errors in many-body calculations of atoms and molecules

The self-healing diffusion Monte Carlo algorithm (SHDMC) [Phys. Rev. B {\bf 79}, 195117 (2009), {\it ibid.} {\bf 80}, 125110 (2009)] is shown to be an accurate and robust method for calculating the ground state of atoms and molecules. By direct comparison with accurate configuration interaction results for the oxygen atom we show that SHDMC converges systematically towards the ground-state wave function. We present results for the challenging N$_2$ molecule, where the binding energies obtained via both energy minimization and SHDMC are near chemical accuracy (1 kcal/mol). Moreover, we demonstrate that SHDMC is robust enough to find the nodal surface for systems at least as large as C$_{20}$ starting from random coefficients. SHDMC is a linear-scaling method, in the degrees of freedom of the nodes, that systematically reduces the fermion sign problem.Comment: Final version accepted in Physical Review Letters. The review history (referees' comments and our replies) is included in the source

Process and System for Establishing a Moving Target Connection for Secure Communications in Client/Server Systems

A system and method performs a moving target blind rendezvous by exchanging data through a distributed hash table. The system allows users to securely send small pieces of information over a network while only requiring an exchange of public keys ahead of time. The system relies on the size and resilience of the BitTorrent Distributed Hash Table and the security properties of cryptographic constructions such as Elliptic Curve Diffie-Hellman key exchange and secure one-way hash functions.https://digitalcommons.usmalibrary.org/patents/1000/thumbnail.jp

SpiDentistry: The Intersection of Dentistry and Spider Silk

Spider silks are an ideal material for periodontal chips/gels because they are biocompatible, biodegradable, lightweight, strong, and create no immune response. Furthermore, the various silks types and forms allow for tunable materials and properties. Spider silk materials may have an advantage over other products because of the ability to release medication more consistently over a longer period of time and be adjusted as needed. Unlike products currently on the market, our chip/gels are biocompatible, which aids in reducing the bodies immune response to periodontal treatment. The ability to incorporate multiple bioactive compounds into the spider silk materials allows them to become multifunctional treatment devices against inflammatory response, infection, and other related complications that come from periodontitis. The purpose of this research project is to develop and test spider silk chips/gels and compare them with products currently on the market to determine the feasibility and potential of spider silk materials. To characterize these silk and conventional materials the release, activity, robustness, geometry, and longevity will be analyzed

Receptor-Coupled Phosphoinositide Hydrolysis in Human Retinal Pigment Epithelium

Carbachol and histamine stimulated phosphoinositide (PPI) hydrolysis in cultured human retinal pigment epithelium (RPE), as reflected by an accumulation of 3 H-inositol phosphates in the presence of 10 m M Li + . Carbachol increased PPI hydrolysis to greater than 600% of basal with an EC 50 of 60 Μ M ; stimulation was linear up to 60 min. This activation likely occurred via the M 3 muscarinic cholinergic receptor based on the IC 50 values for 4-diphenylacetoxy- N -methylpiperidine methiodide (0.47 n M ), pirenzepine (280 n M ), and 11-[[2-[(diethylamino)methyl]-1-piperidinyl]-acetyl]-5,11-dihydro-6 H -pyrido[2,3- b ][1,4]benzodiazepin-6-one (1.4 Μ M ). Carbachol-mediated PPI hydrolysis was decreased by 80% in the absence of extracellular Ca 2+ . Histamine stimulated PPI turnover in a linear manner by 180% with an EC 50 of 20 Μ M by the H 1 histaminergic receptor. Serotonin, glutamate, norepinephrine, and dopamine were inactive. In human RPE, the resting cytoplasmic Ca 2+ concentration, as determined by fura-2 fluorescence, was 138 ± 24 n M . On the addition of carbachol, there was a 180% increase in peak intracellular Ca 2+ ; addition of histamine increased intracellular Ca 2+ by 187%. These results suggest receptor-mediated, inositol lipid hydrolysis is coupled to intracellular Ca 2+ flux in human RPE.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66430/1/j.1471-4159.1991.tb03471.x.pd

Decision-making competence predicts domain-specific risk attitudes

Decision-making competence (DMC) reflects individual differences in rational responding across several classic behavioral decision-making tasks. Although it has been associated with real-world risk behavior, less is known about the degree to which DMC contributes to specific components of risk attitudes. Utilizing a psychological risk-return framework, we examined the associations between risk attitudes and DMC. Italian community residents (n = 804) completed an online DMC measure, using a subset of the original Adult-DMC battery. Participants also completed a self-reported risk attitude measure for three components of risk attitudes (risk-taking, risk perceptions, and expected benefits) across six risk domains. Overall, greater performance on the DMC component scales were inversely, albeit modestly, associated with risk-taking tendencies. Structural equation modeling results revealed that DMC was associated with lower perceived expected benefits for all domains. In contrast, its association with perceived risks was more domain-specific. These analyses also revealed stronger indirect effects for the DMC → expected benefits → risk-taking path than the DMC → perceived risk → risk-taking path, especially for behaviors that may be considered more maladaptive in nature. These results suggest that DMC performance differentially impacts specific components of risk attitudes, and may be more strongly related to the evaluation of expected value of a specific behavior

A predominance of R5-like HIV genotypes in vaginal secretions is associated with elevated plasma HIV-1 RNA levels and the absence of anti-retroviral therapy

HIV expressed in genital secretions provides the inoculum from which transmitting variants are selected, both in sexual transmission and mother-to-infant transmission during partuition. Characterization of HIV levels and genotypes found in vaginal secretions and the impact of anti-retroviral therapy (ART) on this virus can provide valuable insight for the prevention of HIV transmission. Vaginal HIV was evaluated in a cohort of 43 women attending a New Orleans HIV outpatient clinic. Predominant vaginal genotypes were characterized as R5- or X4-like by heteroduplex tracking analyses of the envelope V3 region. Most women (67.4%) shed R5-like genotypes in vaginal secretions which was associated with elevated plasma HIV levels (≥ 10,000 copies HIV-RNA/mL) and absence of ART. Because R5-like genotypes are more frequently associated with transmission, these observations suggest that the majority of women shedding HIV in genital secretions present a transmission risk. The levels of vaginal virus were similar between both groups, but shedding of X4-like genotypes was associated with lower plasma viral loads and the use of ART, suggesting that ART use may impact the genotypes of virus found in the female genital compartment