Convenient Labelling Technique for Mass Spectrometry - Acid Catalyzed Deuterium and Oxygen-18 Exchange via Gas-liquid Chromatography

Mass spectrometry labelling technique - acid catalyzed deuterium and oxygen 18 exchange by gas-liquid chromatograph

An evaluation of praise as a reinforcer for preschoolers\u27 behavior

Behavior analysts and educators often recommend using praise, particularly descriptive praise, despite mixed empirical findings to support this recommendation. We evaluated the effectiveness of praise as a reinforcer during a reinforcer assessment using known tasks with preschoolers in Study 1. Praise functioned as a reinforcer for 2 of 6 participants; the remaining 4 participants required additional reinforcers (edibles) to show a reinforcement effect. We then compared the effectiveness of descriptive versus general praise for acquisition of unknown tacts and assessed participants’ preference for the different types of praise for 4 participants from Study 1. Results showed the efficacy of and preference for general and descriptive praise was idiosyncratic

Response of Spiking Neurons to Correlated Inputs

The effect of a temporally correlated afferent current on the firing rate of a leaky integrate-and-fire (LIF) neuron is studied. This current is characterized in terms of rates, auto and cross-correlations, and correlation time scale $\tau_c$ of excitatory and inhibitory inputs. The output rate $\nu_{out}$ is calculated in the Fokker-Planck (FP) formalism in the limit of both small and large $\tau_c$ compared to the membrane time constant $\tau$ of the neuron. By simulations we check the analytical results, provide an interpolation valid for all $\tau_c$ and study the neuron's response to rapid changes in the correlation magnitude.Comment: 4 pages, 3 figure

Switching the stereochemical outcome of 6-endo-trig cyclizations; Synthesis of 2,6-Cis-6-substituted 4-oxopipecolic acids

A base-mediated 6-endo-trig cyclization of readily accessible enone-derived α-amino acids has been developed for the direct synthesis of novel 2,6-cis-6- substituted-4-oxo-L-pipecolic acids. A range of aliphatic and aryl side chains were tolerated by this mild procedure to give the target compounds in good overall yields. Molecular modeling of the 6-endo-trig cyclization allowed some insight as to how these compounds were formed, with the enolate intermediate generated via an equilibrium process, followed by irreversible tautomerization/neutralization providing the driving force for product formation. Stereoselective reduction and deprotection of the resulting 2,6-cis-6-substituted 4-oxo-L-pipecolic acids to the corresponding 4-hydroxy-L-pipecolic acids was also performed

9th Annual Seminar on Legal Issues for Financial Institutions

Outline of speakers\u27 presentations from the 9th Annual Seminar on Legal Issues for Financial Institutions held by UK/CLE on March 10-11, 1989

Mean-field theory of globally coupled integrate-and-fire neural oscillators with dynamic synapses

This is a pre-print. The definitive version: BRESSLOFF, P.C., 1999. Mean-field theory of globally coupled integrate-and-fire neural oscillators with dynamic synapses. Physical Review E, 60(2), pp.2160-2170 Part B, is available at: http://pre.aps.org/.We analyze the effects of synaptic depression or facilitation on the existence and stability of the splay or asynchronous state in a population of all-to-all, pulse-coupled neural oscillators. We use mean-field techniques to derive conditions for the local stability of the splay state and determine how stability depends on the degree of synaptic depression or facilitation. We also consider the effects of noise. Extensions of the mean-field results to finite networks are developed in terms of the nonlinear firing time map

Characteristics of Sexual Abuse in Childhood and Adolescence Influence Sexual Risk Behavior in Adulthood

Childhood and adolescent sexual abuse has been associated with subsequent (adult) sexual risk behavior, but the effects of force and type of sexual abuse on sexual behavior outcomes have been less well-studied. The present study investigated the associations between sexual abuse characteristics and later sexual risk behavior, and explored whether gender of the child/adolescent moderated these relations. Patients attending an STD clinic completed a computerized survey that assessed history of sexual abuse as well as lifetime and current sexual behavior. Participants were considered sexually abused if they reported a sexual experience (1) before age 13 with someone 5 or more years older, (2) between the ages of 13 and 16 with someone 10 or more years older, or (3) before the age of 17 involving force or coercion. Participants who were sexually abused were further categorized based on two abuse characteristics, namely, use of penetration and force. Analyses included 1177 participants (n=534 women; n=643 men). Those who reported sexual abuse involving penetration and/or force reported more adult sexual risk behavior, including the number of lifetime partners and number of previous STD diagnoses, than those who were not sexually abused and those who were abused without force or penetration. There were no significant differences in sexual risk behavior between nonabused participants and those who reported sexual abuse without force and without penetration. Gender of the child/adolescent moderated the association between sexual abuse characteristics and adult sexual risk behavior; for men, sexual abuse with force and penetration was associated with the greatest number of episodes of sex trading, whereas for women, those who were abused with penetration, regardless of whether the abuse involved force, reported the most episodes of sex trading. These findings indicate that more severe sexual abuse is associated with riskier adult sexual behavior

Frustration wave order in iron(II) oxide spinels

Frustrated magnetic materials provide a great laboratory to study the interplay between classical order and quantum fluctuations. The authors study the frustrated magnetic ground states of two Fe spinel oxides showing that the frustration is a fluctuating characteristic that manifests itself as a “frustration wave

Whole genome sequencing reveals the contribution of long-term carriers in Staphylococcus aureus outbreak investigation

Whole-genome sequencing (WGS) makes it possible to determine the relatedness of bacterial isolates at a high resolution, thereby helping to characterize outbreaks. However, for Staphylococcus aureus, the accumulation of within-host diversity during carriage might limit the interpretation of sequencing data. In this study, we hypothesized the converse, namely, that within-host diversity can in fact be exploited to reveal the involvement of long-term carriers (LTCs) in outbreaks. We analyzed WGS data from 20 historical outbreaks and applied phylogenetic methods to assess genetic relatedness and to estimate the time to most recent common ancestor (TMRCA). The findings were compared with the routine investigation results and epidemiological evidence. Outbreaks with epidemiological evidence for an LTC source had a mean estimated TMRCA (adjusted for outbreak duration) of 243 days (95% highest posterior density interval [HPD], 143 to 343 days) compared with 55 days (95% HPD, 28 to 81 days) for outbreaks lacking epidemiological evidence for an LTC (P = 0.004). A threshold of 156 days predicted LTC involvement with a sensitivity of 0.875 and a specificity of 1. We also found 6/20 outbreaks included isolates with differing antimicrobial susceptibility profiles; however, these had only modestly increased pairwise diversity (mean 17.5 single nucleotide variants [SNVs] [95% confidence interval {CI}, 17.3 to 17.8]) compared with isolates with identical antibiograms (12.7 SNVs [95% CI, 12.5 to 12.8]) (P < 0.0001). Additionally, for 2 outbreaks, WGS identified 1 or more isolates that were genetically distinct despite having the outbreak pulsed-field gel electrophoresis (PFGE) pulsotype. The duration-adjusted TMRCA allowed the involvement of LTCs in outbreaks to be identified and could be used to decide whether screening for long-term carriage (e.g., in health care workers) is warranted. Requiring identical antibiograms to trigger investigation could miss important contributors to outbreaks