Impulsive and self-control choices in opioid-dependent patients and non-drug-using control patients: Drug and monetary rewards.

Delay discounting was investigated in opioid-dependent and non-drug-using control participants. The latter participants were matched to the former on age, gender, education, and IQ. Participants in both groups chose between hypothetical monetary rewards available either immediately or after a delay. Delayed rewards were $ 1,000, and the immediate-reward amount was adjusted until choices reflected indifference. This procedure was repeated at each of 7 delays (1 week to 25 years). Opioid-dependent participants were given a second series of choices between immediate and delayed heroin, using the same procedures (i.e., the amount of delayed heroin was that which could be purchased with $1,000). Opioid-dependent participants discounted delayed monetary rewards significantly more than did non-drug-using participants. Furthermore opioid-dependent participants discounted delayed heroin significantly more than delayed money. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Molecular evolution modeled as a fractal Poisson process in agreement with mammalian sequence comparisons

The fractal doubly stochastic Poisson process (FDSPP) model of molecular evolution, like other doubly stochastic Poisson models, agrees with the high estimates for the index of dispersion found from sequence comparisons. Unlike certain previous models, the FDSPP also predicts a positive geometric correlation between the index of dispersion and the mean number of substitutions. Such a relationship is statistically proven herein using comparisons between 49 mammalian genes. There is no characteristic rate associated with molecular evolution according to this model, but there is a scaling relationship in rates according to a fractal dimension of evolution. The FDSPP is a suitable replacement for the homogeneous Poisson process in tests of the lineage dependence of rates and in estimating confidence intervals for divergence times. As opposed to other fractal models, this model can be interpreted in terms of Darwinian selection and drift.     

The last year of life: a representative study of deceased patients. Living arrangement, place of death and utilization of health resources

We have demonstrated the polymorphism of the beta-tubulin gene region in Leishmania and its value in the identification of the parasite. In this work we have shown that the coding region of the gene has sufficient variation to accurately discriminate these parasites at the subgenus level. Nevertheless, intrasubgenus diversity, for particular restriction enzymes, was found in New World Leishmania belonging to the Leishmania subgenus. For instance, differences were found between mexicana and amazonensis strains. A unique pattern at the species level was found in particular species of both subgenera, e.g. L. (L.) major strain P and L. (L.) tropica belonging to the Leishmania subgenus, and L. (V.) panamensis strain LS94 from the Viannia subgenus. Particular endonucleases are diagnostic in Leishmania species discrimination as in the case of PvuII for the mexicana and amazonensis. This variation evidenced in the beta-tubulin gene region of Leishmania also occurred in other Kinetoplastida e.g. Trypanosoma cruzi, Leptomonas spp. and Crithidia spp. Moreover, these organisms showed a different genomic fingerprinting for the beta-tubulin gene among them and also Leishmania. Thus, the polymorphism of the coding region of the beta-tubulin gene can be used as a molecular marker for the identification of Leishmania.     

The Dynamic Emission Zone in Sandwich Polymer Light‐Emitting Electrochemical Cells

In light‐emitting electrochemical cells (LECs), the position of the emission zone (EZ) is not predefined via a multilayer architecture design, but governed by a complex motion of electrical and ionic charges. As a result of the evolution of doped charge transport layers that enclose a dynamic intrinsic region until steady state is reached, the EZ is often dynamic during turn‐on. For thick sandwich polymer LECs, a continuous change of the emission color provides a direct visual indication of a moving EZ. Results from an optical and electrical analysis indicate that the intrinsic zone is narrow at early times, but starts to widen during operation, notably well before the electrical device optimum is reached. Results from numerical simulations demonstrate that the only precondition for this event to occur is that the mobilities of anions (μ_a) and cations (μ_c) are not equal, and the direction of the EZ shift dictates μ_c > μ_a. Quantitative ion profiles reveal that the displacement of ions stops when the intrinsic zone stabilizes, confirming the relation between ion movement and EZ shift. Finally, simulations indicate that the experimental current peak for constant‐voltage operation is intrinsic and the subsequent decay does not result from degradation, as commonly stated.     

Risk implications of digital reactor protection system operating experience

This paper summarizes an in-depth review of the US nuclear operating experience with the first generation of digital reactor protection systems. The accumulated operating experience from 1984 to 2006 on these first generation digital reactor protection system functions exceeds 1.27 million hours (145.5 yr). A review of failure event reports identified 141 specific events associated with these systems on seven US nuclear power plants. Twenty-six of these events involved some type of common cause failure mechanism (predominantly redundant sensors/channels being out of calibration), which temporarily rendered redundant portions of the overall trip function degraded. Most of these failures were found not to be unique to digital systems. Six of the common cause failure events were more severe and involved situations where incorrect addressable constant data sets were systematically loaded into all redundant computer channels due to personnel errors. One of these events involved a latent software design change error introduced during a software update, which would prevent proper operation, given an unlikely event involving failure of three out of four sensors of one type.Based upon this review of digital system operating experience, a series of risk assessment calculations were performed to evaluate the safety significance of the observed failure events. From the insights gained in this work, it is possible to develop a framework for establishing digital reactor protection system reliability requirements that can be related back to regulatory safety goal objectives and operating experience.     

Flank milling of compliant workpieces with chamfered tools

The use of chamfered tools is widely spread in cutting processes. Prior investigation show, that a chamfer on the rake face of a milling tool can increase the stability of cutting processes significantly due to a contact between the chamfer surface and the workpiece and the resulting damping forces. In addition to higher process stability, it is possible that the chamfer shows positive effects on the machined surface as well. A sufficient chamfer length can cut off the feed marks on the machined surface, but also damping effects on the process vibrations can lead to a better flank surface when milling compliant parts or tools as well. This paper describes an approach of simulation of machining of the flank surface with consideration of the chamfer geometry. In the experimental and simulative investigations it was found that by the reduction of extensive workpiece vibrations, the chamfer does have positive effect on the flank surface quality due to a contact between the chamfer and the workpiece. Furthermore, this contact does apparently occur earlier than a theoretical consideration would predict from the kinematics of the process. With increase of the chamfer length on the other hand, also augmented appearance of smearing effects on the surface, which decrease the surface quality, was observed.     

Buprenorphine medication versus voucher contingencies in promoting abstinence from opioids and cocaine.

During a 12-week intervention, opioid dependent participants (N = 120) maintained on thrice-a-week (M, W, F) buprenorphine plus therapist and computer-based counseling were randomized to receive: (a) medication contingencies (MC = thrice weekly dosing schedule vs. daily attendance and single-day 50% dose reduction imposed upon submission of an opioid and/or cocaine positive urine sample); (b) voucher contingency (VC = escalating schedule for opioid and/or cocaine negative samples with reset for drug-positive samples); or (c) standard care (SC), with no programmed consequences for urinalysis results. VC resulted in better 12-week retention (85%) compared to MC (58%; p = 0.009), but neither differed from SC (76% retained). After adjusting for baseline differences in employment, and compared to SC, the MC group achieved 1.5 more continuous weeks of combined opioid/cocaine abstinence (p = 0.030), while the VC group had 2 more total weeks of abstinence (p = 0.048). Drug use results suggest that both the interventions were efficacious, with effects primarily in opioid rather than cocaine test results. Findings should be interpreted in light of the greater attrition associated with medication-based contingencies versus the greater monetary costs of voucher-based contingencies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modeling the effects of combined behavioral and pharmacological treatment on cigarette smoking: behavioral-economic analyses

Effects of different response requirements, response-independent cigarette puffs, and an alternative nondrug reinforcer on cigarette smoking were assessed in 2 experiments. The response requirement to obtain 2 puffs on a cigarette was manipulated while various numbers of response-independent puffs were provided (0, 6, or 12 in Experiment 1; 0 or 12 in Experiment 2). In Experiment 2, effects of response-dependent money ($0.25) on smoking were assessed within subjects. Response-dependent puff consumption decreased as price increased and as the number of response-independent puffs increased. Concurrently available money also decreased response-dependent smoking. The largest decrease in smoking occurred when puffs were at the highest price and when response-independent puffs and response-dependent money were both concurrently available. Findings suggest that combined pharmacological and behavioral interventions produce the greatest reductions in smoking.