Naloxone blocks reinforcement but not motivation in an operant runway model of heroin-seeking behavior.

Examined the effects of opiate receptor antagonism on both the motivation to seek heroin and the reinforcing consequences of heroin administration. Male rats were trained to discriminate between olfactory cues predicting either the delivery of intravenous heroin reinforcement (S+) or saline (S-). Subjects were then tested in the presence of the opiate receptor antagonist, naloxone (0.5, 1.0, or 3.0 mg/kg intraperitoneally) in a straight-arm runway. Naloxone had no effect on either S+ or S- trials. However, 24 hr later on the first posttreatment trial, Ss that had received heroin in the presence of naloxone (on the previous trial) now traversed the alley more slowly when presented with the S+. These data suggest that although the motivation to seek heroin was not disrupted by naloxone, the reinforcing consequences of heroin administration were. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Standards-ethics and the safety of computer systems

The issue of responsibility for computer failures in critical systems is addressed, taking medical information systems as an example. Three basic modes of ethical analysis are defined and used to analyze the ethical questions raised for such systems. The first, called normative ethics, seeks to develop and justify rules for right conduct. The second, called the ethics of virtue, asks what kind of person does the right thing; thus, it concerns questions of character. The third mode, called social ethics, recognizes that values and choices are not only expressed in individual actions, but are embodied effectively in social structures, and asks what structures are needed to support values such as justice and respect for human life and dignity     

Chronic relapsing experimental autoimmune encephalomyelitis: effects of insulin-like growth factor-I treatment on clinical deficits, lesion severity, glial responses, and blood brain barrier defects

Chronic relapsing experimental autoimmune encephalomyelitis (crEAE), a model for multiple sclerosis, was used to test 2 regimens of insulin-like growth factor-I (IGF-I) treatment. We induced crEAE by injecting 3x10(7) myelin basic protein-(MBP) sensitized lymph node cells into adult female SJL/J mice. Fifty-one mice, divided randomly into 4 groups, were used in the first trial. Two groups received IGF-I (a gift of Cephalon, Inc.) 0.6 mg/kg/d subcutaneously from day 7 to day 16 and the other two groups received placebo injections. IGF-I treatment reduced clinical deficits during the first attack and during 2 subsequent relapses. Image analysis of immunostained and histological sections showed that IGF-I treatment reduced BBB defects and both the numbers and sizes of inflammatory, demyelinating, and demyelinated lesions. Twelve mice that had recovered from their first attack were used in our second trial to evaluate possible adverse effects of prolonged treatment with a higher dose of IGF-I. Six received 1.2 mg/kg/d for 6 weeks (days 19-63). No adverse effects of IGF-I treatment were identified. The eyes, hearts, livers, and kidneys of IGF-I-treated mice were normal histologically and their spleens also appeared normal except for mild to moderate microscopic increases in lymphopoesis. Our results suggest that prolonged IGF-I treatment is well tolerated and that the anti-inflammatory effects of IGF-I have a major role in reducing clinical deficits and lesion severity in crEAE. These effects, if present in multiple sclerosis, may benefit patients with this disease.     

Modeling multimode-input star couplers in polymers

In this paper, we present the first numerical study of highly multimode-input integrated-optic star couplers. Although the design utilizes the physical quantities appropriate for a polymer device, many of the results are applicable to multimode-input star couplers using a wide range of materials. Design parameters explored include the input-port waveguide width, refractive index difference, and insertion angle. The simulation work is done utilizing the beam propagation method. The statistically based scaling parameters for these highly multimode structures are shown to be compatible with the results of an analytical model which is suitable for initial device design     

Interactions of task challenge and intrinsic and extrinsic motivations in college achievement.

Examined effects of 3 levels each of personal intrinsic and extrinsic motivational dispositions on grade point average (GPA) in college freshman courses rated by the 188 students as their most and least challenging. Extrinsic motivation was related to GPA by an inverted-U function, and the linear correlation coefficient was significant (p     

Transplanting shrubs for revegetation of salt-affected soils

Vegetation (secondary) succession is extremely slow on soils contaminated with soluble salts by petroleum exploration activities in arid and semiarid areas. Excessive salt accumulations interfere with seed germination and seedling establishment of most species used for revegetation. Establishment and growth of transplanted fourwing saltbush (Atriplex canescens) seedlings and rooted stem cuttings, and seedlings of oldman saltbush (Atriplex nummularia), winterfat (Ceratoides lanata), and prostrate kochia (Kochia prostrata) were evaluated on three saline-sodic (EC (electrical conductivity) = 23 − 93 dS m^-1, ESP (exchangeable sodium percentage) = 13−46%) oil well reserve pits over a three-year period. Survival of fourwing saltbush seedlings from an accession not adapted to saline soils was only 32%, compared with 73% for seedlings or stem cuttings from an accession adapted to saline soil. Oldman saltbush suffered 100% mortality subsequent to subfreezing temperatures during the first winter following planting. Survival of winterfat and prostrate kochia transplants was 61 and 48%, respectively, after three years, and growth of these species was acceptable on the saline-sodic soils. Selection or specific accessions of species adapted to the existing conditions of the site to be revegetated appeared most promising for revegetation under extremely harsh environmental conditions.     

The impact of negative moods on self-enhancing cognitions: The role of reflective versus ruminative mood orientations.

This research program examined how self-focused attention to feelings affects the relation between mood negativity and self-enhancing thought. The primary hypothesis was that the particular manner in which people focus on their moods (reflective vs. ruminative) determines whether they reveal positive (i.e., mood-incongruent) or negative (i.e., mood-congruent) self-relevant thoughts in response to negative moods. Studies 1-4 revealed that social comparisons, temporal comparisons, and other self-enhancing cognitions (i.e., attributions, disidentification, relationship evaluations) are more likely to be mood incongruent when people adopt a reflective orientation to their negative feelings and more likely to be mood congruent when they adopt a ruminative orientation. Additionally, moods and mood orientations affected self-enhancing thoughts through the mediating influence of mood regulation goals and intentions (Studies 5 and 6). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Timing of EEG-based cursor control

Recent studies show that humans can learn to control the amplitude of electroencephalography (EEG) activity in specific frequency bands over sensorimotor cortex and use it to move a cursor to a target on a computer screen. EEG-based communication could be a valuable new communication and control option for those with severe motor disabilities. Realization of this potential requires detailed knowledge of the characteristic features of EEG control. This study examined the course of EEG control after presentation of a target. At the beginning of each trial, a target appeared at the top or bottom edge of the subject's video screen and 1 sec later a cursor began to move vertically as a function of EEG amplitude in a specific frequency band. In well-trained subjects, this amplitude was high at the time the target appeared and then either remained high (i.e., for a top target) or fell rapidly (i.e., for a bottom target). Target-specific EEG amplitude control began 0.5 sec after the target appeared and appeared to wax and wane with a period of approximately 1 sec until the cursor reached the target (i.e., a hit) or the opposite edge of the screen (i.e., a miss). Accuracy was 90% or greater for each subject. Top-target errors usually occurred later in the trial because of failure to reach and/or maintain sufficiently high amplitude, whereas bottom-target errors usually occurred immediately because of failure to reduce an initially high amplitude quickly enough. The results suggest modifications that could improve performance. These include lengthening the intertrial period, shortening the delay between target appearance and cursor movement, and including time within the trial as a variable in the equation that translates EEG into cursor movement.     

The application of S−2→S+6 chemistry to the refining of copper

It has been demonstrated that the ancient process of chloridizing roasting functions as a reduction process for copper oxide when carried out in a closed condensed system. Thermodynamic data are tabulated to show that this reduction process is highly selective for copper; thus it is potentially useful as a copper refining process. The results of brief experimental programs are reported for eight different systems in which metal sulfides or sulfur interact with copper (or copper plus impurity) oxides and an alkali chloride to yield either copper metal or a reduced oxide. Experiments directed toward understanding the role of impurities in the reactions indicate that they tend to concentrate in the alkali sulfate oxidation product of the reactions. Formerly with the General Electric Company, Research and Development Center