The QCD Potential at O(1/m2): Complete spin-dependent and spin-independent result

Within an effective field theory framework, we obtain an expression, with O(1/m2) accuracy, for the energies of the gluonic excitations between heavy quarks, which holds beyond perturbation theory. For the singlet heavy-quarkantiquark energy, in particular, we also obtain an expression in terms of Wilson loops. This provides, twenty years after the seminal work of Eichten and Feinberg, the first complete expression for the heavy quarkonium potential up to O(1/m2) for pure gluodynamics. Several errors present in the previous literature (also in the work of Eichten and Feinberg) have been corrected. We also briefly discuss the power counting of NRQCD in the nonperturbative regime.

Subclass problem-dependent design for error-correcting output codes

A common way to model multiclass classification problems is by means of Error-Correcting Output Codes (ECOCs). Given a multiclass problem, the ECOC technique designs a code word for each class, where each position of the code identifies the membership of the class for a given binary problem. A classification decision is obtained by assigning the label of the class with the closest code. One of the main requirements of the ECOC design is that the base classifier is capable of splitting each subgroup of classes from each binary problem. However, we cannot guarantee that a linear classifier model convex regions. Furthermore, nonlinear classifiers also fail to manage some type of surfaces. In this paper, we present a novel strategy to model multiclass classification problems using subclass information in the ECOC framework. Complex problems are solved by splitting the original set of classes into subclasses and embedding the binary problems in a problem-dependent ECOC design. Experimental results show that the proposed splitting procedure yields a better performance when the class overlap or the distribution of the training objects conceal the decision boundaries for the base classifier. The results are even more significant when one has a sufficiently large training size.

State-to-state reaction probabilities within the quantum transition state framework

Rigorous quantum dynamics calculations of reaction rates and initial state-selected reaction probabilities of polyatomic reactions can be efficiently performed within the quantum transition state concept employing flux correlation functions and wave packet propagation utilizing the multi-configurational time-dependent Hartree approach. Here, analytical formulas and a numerical scheme extending this approach to the calculation of state-to-state reaction probabilities are presented. The formulas derived facilitate the use of three different dividing surfaces: two dividing surfaces located in the product and reactant asymptotic region facilitate full state resolution while a third dividing surface placed in the transition state region can be used to define an additional flux operator. The eigenstates of the corresponding thermal flux operator then correspond to vibrational states of the activated complex. Transforming these states to reactant and product coordinates and propagating them into the respective asymptotic region, the full scattering matrix can be obtained. To illustrate the new approach, test calculations study the D + H2(ν, j) → HD(ν′, j′) + H reaction for J = 0.

Stage of change of cigarette smoking in alcohol-dependent patients.

Despite the heavy burden of tobacco-related problems in alcohol-dependent patients, little effort has been directed toward reducing the prevalence of smoking in these patients. It seems reasonable to develop nicotine addiction treatments for alcohol-dependent patients based on the smoker's stage of change. To assess the stage of change for tobacco consumption and possible quitting barriers in alcohol-dependent patients, 88 consecutively admitted inpatients of a Swiss university-affiliated alcohol withdrawal clinic were interviewed with a semistructured schedule. More than half of the alcohol-dependent smokers (50.7%) considered the possibility of smoking cessation or had already decided to stop, although the majority (83.1%) were highly dependent smokers. Positive reinforcers were factors influencing motivation both to stop smoking as well as to continue smoking, whereas negative reinforcers had no influence. As recovering alcoholic patients are often interested in smoking cessation and the introduction of nicotine treatment interventions has been shown not to jeopardize the outcome of alcohol treatment, alcohol treatment programs should include counseling for smoking cessation. Education and training for staff is essential, as their beliefs and habits remain an important barrier.

Silicon quantum dots embedded in a SiO2 matrix: From structural study to carrier transport properties

We study the details of electronic transport related to the atomistic structure of silicon quantum dots embedded in a silicon dioxide matrix using ab initio calculations of the density of states. Several structural and composition features of quantum dots (QDs), such as diameter and amorphization level, are studied and correlated with transport under transfer Hamiltonian formalism. The current is strongly dependent on the QD density of states and on the conduction gap, both dependent on the dot diameter. In particular, as size increases, the available states inside the QD increase, while the QD band gap decreases due to relaxation of quantum confinement. Both effects contribute to increasing the current with the dot size. Besides, valence band offset between the band edges of the QD and the silica, and conduction band offset in a minor grade, increases with the QD diameter up to the theoretical value corresponding to planar heterostructures, thus decreasing the tunneling transmission probability and hence the total current. We discuss the influence of these parameters on electron and hole transport, evidencing a correlation between the electron (hole) barrier value and the electron (hole) current, and obtaining a general enhancement of the electron (hole) transport for larger (smaller) QD. Finally, we show that crystalline and amorphous structures exhibit enhanced probability of hole and electron current, respectively.

MOS-SF-36 in evaluating health-related quality of life in alcohol-dependent patients.

Health-related quality of life (HRQoL) was evaluated in a sample of alcohol-dependent patients with the 36-item Medical Outcome Study Short-Form Health Survey (MOS-SF-36). The instrument was administered to 147 patients (77% males), aged 26-78, with a DSM-III-R diagnosis of alcohol dependence. The Hamilton Depression Scale (HDS), the Severity of Alcohol Dependence Questionnaire (SADQ), and the Addiction Severity Index (ASI) were also administered to the first 100 patients included in the study. The reliability and validity of the MOS-SF-36 were evaluated. Test-retest intraclass coefficients for a 10-day interval were in the range .65 to .79, whereas the Cronbach alpha coefficient indicated good internal consistency (range .70 to .89). Compared to scores observed in the general population, MOS-SF-36 scores for alcohol-dependent patients were relatively low (indicating worse perception of HRQoL), especially in the psychological and role dimensions (range 52/100 to 55/100), but were closer to populational values in the physical and functional dimensions (range 61/100 to 75/100)). The highest correlation between MOS-SF-36 dimensions and HDS was found in the MOS-SF-36 "mental health" dimension (r=-.56, p < .001); this dimension was also correlated highly with the psychiatric dimension of the ASI (r=-.73, p < .001). The eight dimensions of the MOS-SF-36 were 21% to 127% lower in patients with HDS greater than or equal to 16 (major depression) compared to those with HDS less than or equal to 7 (absence of depression). The MOS-SF-36 dimensions were 10% to 141% lower in patients with high "ASI alcohol" scores, indicating worse HRQoL profiles with a higher severity of alcohol dependence. The MOS-SF-36 presents good criteria for reliability and validity in alcohol-dependent patients. The results suggested that alcohol-dependent patients perceived their problems more as psychological than physical. The severity of alcohol dependence and depression seemed to influence the perception of HRQoL negatively.

First-passage and escape problems in the Feller process

The Feller process is an one-dimensional diffusion process with linear drift and state-dependent diffusion coefficient vanishing at the origin. The process is positive definite and it is this property along with its linear character that have made Feller process a convenient candidate for the modeling of a number of phenomena ranging from single-neuron firing to volatility of financial assets. While general properties of the process have long been well known, less known are properties related to level crossing such as the first-passage and the escape problems. In this work we thoroughly address these questions.

Involuntary treatment of alcohol-dependent patients: a study of 17 consecutive cases of civil commitment.

AIM: To investigate the baseline and follow-up characteristics of a group of alcohol-dependent patients being treated under civil commitment. METHODS: This study involved a cross-sectional comparative analysis of baseline characteristics and a follow-up survey of a group of committed alcoholic patients. The study was undertaken in the Alcohol Unit of a 1,000-bed general and university hospital. The study included 17 consecutive cases of civil commitment (representing 15 patients, of whom 2 were committed twice) and a comparative group of 34 randomly selected age- and sex-matched patients. Baseline characteristics of the cases (at the time of commitment) and of patients from the comparative group were collected from medical records, including sociodemographic data, medical condition, patterns of drinking and number and dates of previous treatments for alcohol-related problems. A structured follow-up interview of the cases provided information on their medical condition, social status, patterns of alcohol use, type and duration of residential treatment as well as their perceptions of commitment. RESULTS: During a 4-year period, our Unit referred 23 cases of alcohol-dependent patients (out of 367) to the Guardianship Authority, requesting civil commitment. On 17 occasions, patients were committed to residential treatment, including 2 patients who underwent commitment on two separate occasions, thus representing a total of 15 different patients. In comparison with age- and sex-matched patients seen at the Unit, the cases were characterized by multiple medical, social and psychological alcohol-related impairments. At the time of follow-up, 14 out of 15 patients were alive, among whom 10 agreed to be interviewed. Eight of these reported complete abstinence, whereas 9 considered their alcohol problem as less severe than before. The average duration of commitment was 29 weeks. The majority of patients retrospectively considered the measure as having been justified and useful. The patients' satisfaction with the decision to commit was higher among women than among men. Health-related quality of life at the time of follow-up, as assessed by the MOS 36-Item Short Form Health Survey questionnaire, was good on average and better than that usually reported by other cohorts of alcoholics undergoing treatment. CONCLUSIONS: The usefulness of residential civil commitment of certain severely impaired alcohol-dependent patients is underscored. This study suggests that civil commitment not only may save the lives of endangered patients but could also be a health-promoting measure that may sometimes allow for recovery from dependence. Unexpectedly, this measure was retrospectively well accepted by many patients, who considered the commitment decision as having been justified and useful.

A non-extensive maximum entropy based regulations method for bad conditioned inverse problems

A regularization method based on the non-extensive maximum entropy principle is devised. Special emphasis is given to the q=1/2 case. We show that, when the residual principle is considered as constraint, the q=1/2 generalized distribution of Tsallis yields a regularized solution for bad-conditioned problems. The so devised regularized distribution is endowed with a component which corresponds to the well known regularized solution of Tikhonov (1977).

Problems of the randomization test for AB designs

N = 1 designs imply repeated registrations of the behaviour of the same experimental unit and the measurements obtained are often few due to time limitations, while they are also likely to be sequentially dependent. The analytical techniques needed to enhance statistical and clinical decision making have to deal with these problems. Different procedures for analysing data from single-case AB designs are discussed, presenting their main features and revising the results reported by previous studies. Randomization tests represent one of the statistical methods that seemed to perform well in terms of controlling false alarm rates. In the experimental part of the study a new simulation approach is used to test the performance of randomization tests and the results suggest that the technique is not always robust against the violation of the independence assumption. Moreover, sensitivity proved to be generally unacceptably low for series lengths equal to 30 and 40. Considering the evidence available, there does not seem to be an optimal technique for single-case data analysis

First-passage and escape problems in the Feller process

The Feller process is an one-dimensional diffusion process with linear drift and state-dependent diffusion coefficient vanishing at the origin. The process is positive definite and it is this property along with its linear character that have made Feller process a convenient candidate for the modeling of a number of phenomena ranging from single-neuron firing to volatility of financial assets. While general properties of the process have long been well known, less known are properties related to level crossing such as the first-passage and the escape problems. In this work we thoroughly address these questions.

Molecular mechanism of a green-shifted, pH-dependent red fluorescent protein mKate variant.

Fluorescent proteins that can switch between distinct colors have contributed significantly to modern biomedical imaging technologies and molecular cell biology. Here we report the identification and biochemical analysis of a green-shifted red fluorescent protein variant GmKate, produced by the introduction of two mutations into mKate. Although the mutations decrease the overall brightness of the protein, GmKate is subject to pH-dependent, reversible green-to-red color conversion. At physiological pH, GmKate absorbs blue light (445 nm) and emits green fluorescence (525 nm). At pH above 9.0, GmKate absorbs 598 nm light and emits 646 nm, far-red fluorescence, similar to its sequence homolog mNeptune. Based on optical spectra and crystal structures of GmKate in its green and red states, the reversible color transition is attributed to the different protonation states of the cis-chromophore, an interpretation that was confirmed by quantum chemical calculations. Crystal structures reveal potential hydrogen bond networks around the chromophore that may facilitate the protonation switch, and indicate a molecular basis for the unusual bathochromic shift observed at high pH. This study provides mechanistic insights into the color tuning of mKate variants, which may aid the development of green-to-red color-convertible fluorescent sensors, and suggests GmKate as a prototype of genetically encoded pH sensors for biological studies.