Insulin receptor substrate-2 in the ventral tegmental area regulates behavioral responses to cocaine.

Neurotrophic factor signaling modulates cellular and behavioral responses to drugs of abuse. Among other biochemical adaptations, chronic exposure to abused drugs decreases the expression of insulin receptor substrate-2 (IRS-2; a protein involved in neurotrophic signaling) in the ventral tegmental area (VTA), a neural substrate for many drugs of abuse. Using viral-mediated gene transfer to locally alter the activity of IRS-2, the authors show that overexpression of IRS-2 in the VTA results in an enhanced preference for environments previously paired with cocaine, as measured by the place conditioning paradigm, whereas blockade of IRS-2 activity results in avoidance of cocaine-paired compartments. In addition, IRS-2 overexpression leads to enhanced cocaine-induced locomotor activity, and blockade of IRS-2 expression significantly blunts behavioral responses to cocaine. These results demonstrate that levels of IRS-2 in the VTA regulate responsiveness to the behavioral effects of cocaine. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spatial activity and labour market patterns: A connectivity analysis of commuting flows in Germany

The spatial activity patterns of firms in a multi-regional system are closely connected with the structure and evolution of regional labour markets. Based on an extensive data set (cross-section) on commuting flows in Germany, this paper aims to identify the relationship between entrepreneurial activity and spatial labour markets, by employing in particular the concept of ‘entrepreneurial city’. A network connectivity model is adopted to assess connectivity patterns, using the power-law and exponential law as a statistical test framework, in order to detect the presence of economic activity hubs that may resemble the concept of entrepreneurial cities. Various results are presented and interpreted in the final part of the paper.     

A prolonged outbreak of Salmonella Montevideo infections associated with multiple locations of a restaurant chain in Phoenix, Arizona, 2008

An outbreak of Salmonella serotype Montevideo infections associated with multiple locations of restaurant chain A in Phoenix, AZ, was identified in July 2008. One infected individual reported eating at a chain A catered luncheon where others fell ill; we conducted a cohort study among attendees to identify the vehicle. Food and environmental samples collected at six chain A locations were cultured for Salmonella. Restaurant inspection results were compared among 18 chain A locations. Routine surveillance identified 58 Arizona residents infected with the outbreak strain. Three chain A locations, one of which catered the luncheon, were named by two or more case patients as a meal source in the week prior to illness onset. In the cohort study of luncheon attendees, 30 reported illness, 10 of which were later culture confirmed. Illness was reported by 30 (61%) of 49 attendees who ate chicken and by 0 of 7 who did not. The outbreak strain was isolated from two of these three locations from uncooked chicken in marinade, chopped cilantro, and a cutting board dedicated to cutting cooked chicken. Raw chicken, contaminated before arrival at the restaurant, was the apparent source of this outbreak. The three locations where two or more case patients ate had critical violations upon routine inspection, while 15 other locations received none. Poor hygiene likely led to cross-contamination of food and work areas. This outbreak supports the potential use of inspections in identifying restaurants at high risk of outbreaks and the need to reduce contamination of raw products at the source and prevent cross-contamination at the point of service.     

A programmable voltage reference optimized for power management applications

A 3-bits programmable, low drift, high PSRR and high precision voltage reference, optimized for Power Management (PM) applications, is presented. The topology is based on a high-performance bandgap voltage reference that presents a PSRR of up to 80 dB, which is required in PM applications, because they employ mixed-signal circuits, where high frequency switching noise is present. The proposed approach was successfully verified in a standard 0.35 μm CMOS process. The experimental results confirmed that, for power supply between 3.0 and 3.3 V, and temperatures in ?20°C to 80°C range, the programmable output voltage V _REF exhibits a worst case precision of ±3%.     

Temperature and conversion patterns in a network of catalytic reactors for methanol synthesis with different switch strategies

A network of connected catalytic reactors with periodically switched inlet and outlet sections is numerically studied for reversible exothermic reactions. The methanol synthesis is selected as representative process example and two different switch strategies are compared with the objective of overcoming the conversion limits imposed by thermodynamic equilibrium. The first strategy, which is the most considered in literature, consists of periodically switching the feed to the second reactor of the current reactor sequence while the second strategy is implemented by periodically switching the feed to the last reactor of the current sequence. Periodic regimes corresponding to single square-like temperature waves travelling over the catalytic bed and characterized by comparable methanol conversion values are detected for both the considered strategies. These regimes exhibit, however, a significantly larger domain of existence for the second strategy. Moreover, the second strategy gives rise to other periodic regimes corresponding to spatiotemporal temperature patterns characterized by different spatial and temporal periodicity. These patterns arise in the form of temperature wave trains and ensure methanol conversion values significantly larger than those found under periodic regimes characterized by single temperature waves.     

Polymerization,grafting and adsorption in the presence of inorganic substrates: Thermal polymerization of styrene with untreated and γ-irradiated silica gel as a case study

The search for innovative and well-defined organic–inorganic hybrid materials demands that the interplay between polymerization reactions, chemical reactivity, and physical adsorption be fully understood. We examine the case study of the thermal polymerization of styrene in the presence of silica, and the effect of pre-irradiation of silica with γ-rays. The effect of adsorption of styrene-derived radical species on the silica support and polymerization conditions on free and grafted (unextractable) polystyrenes and on polymerization mechanism is discussed on the basis of previous literature findings and new data. Evidence is provided of silica derivatization with various species besides polystyrene (¹³C CPMAS NMR), including products from a β-scission of the adsorbed radical intermediates ensuing oxygen donation from the silica network. The polymerization mechanism can be cationic as well as radical, depending on reaction conditions, and the cationic route prevails in the grafting of polystyrene from silica, resulting in a bimodal molecular weight distribution.     

A Game Theory Approach Using Excel

Understanding the behavior of companies in market conditions has been an important topic of studies for the economists and mathematicians. Many companies have treated their relationship of service providers as a game. Thus, the attitudes of the players can be endowed with rational thinking, which leads to the conclusion that the use of game theory as a tool to understand such behavior is of great importance. Based on the previous studies, this paper presents a study on the cooperative game theory, discussing the Nash equilibrium in pure and mixed strategies, treating solutions using the minimax John Von Neumarm theorem and illustrating a mathematical modeling of a game theory problem. Furthermore, a solution of linear programming using Microsoft Excel is also proposed and presented. The methodology adopted to model the problem may help students to familiarize themselves to game theory.