Simulation of the time evolution of the Wigner function with a first-principles Monte Carlo method.

The implementation of Monte Carlo methods acting in the quantum phase space is hindered by the fact that quantum phase-space information is available only through quasiprobability densities. In this work, we present a first-principles Monte Carlo method employing a hidden variables representation. This allows the full quantum time evolution of an arbitrary initial quantum state to be calculated by a classical Monte Carlo algorithm, even for systems subjected to time-dependent potentials. Guidelines for implementing a practical algorithm are presented.

Pattern dynamics in a perturbed printer's instability experiment.

We report experimental results concerning observation of a pattern forming system, subject to directional viscous fingering (printer's instability). This system was excited by a time-dependent, periodic perturbation. A variety of spatiotemporal effects was observed, including pattern transient dynamics, wave vector selection, and morphological transitions. Detailed measurement of pattern shape and its associated Fourier modes assured the detection of a crossover between different regimes of the pattern evolution.

Direct observation of a precursor in a complex system.

A precursor is a kind of instability in a nonequilibrium system observed prior to a bifurcation. It has been observed in important natural phenomena such as earthquakes and epileptic seizures. In most cases just qualitative results were reported, with the exception of some quantitative observations of noisy precursors. We report the observation of precursors excited by a deterministic perturbation. Quantitative characterization of this type of precursor is important in predicting a bifurcation in advance. This predicting ability comes from a dynamical structure present on the perturbed system.

Design and synthesis of novel potent antinociceptive agents: methyl-imidazolyl N-acylhydrazone derivatives.

This paper describes recent results of design, synthesis and pharmacological evaluation of new N-heterocyclic functionalized N-acylhydrazone compounds, belonging to the 2-methyl-imidazolyl-3-acylhydrazone class (4a-e). These compounds were planned by applying the molecular simplification strategy to propose the structural modifications on the previously described functionalized imidazo [1,2-a]pyridine 3-acylhydrazone series (2), which presented an important analgesic profile. This new series (4) was synthesized in order to investigate the possible pharmacophoric contribution of the N-heteroaromatic ring and N-acylhydrazone moieties to the analgesic activity. Compounds 4a-b are the most potent antinociceptive agents from this series.

Experimental test of the Warren-Langer model in nematic-isotropic planar interfaces.

In a directional solidification apparatus, the recoil of the nonsteady planar nematic-isotropic interface of the liquid crystal 8CB doped with hexachloroethane was measured, for different pulling velocities. Results agree very well with the predictions of our two-sided extension of Warren and Langer's one-sided model [Phys. Rev. E 47, 2702 (1993)], therefore supporting the validity of their ansatz about the evolution of the dopant concentration field. From the comparison between experiment and theory we obtain values for the segregation and diffusion coefficients of hexachloroethane in 8CB comparable to those found in the literature and measured by other methods. Using the same procedure, we measured the value of the segregation coefficient of 8CB doped with water as a function of applied sinusoidal electric field perpendicular to the sample, along the homeotropic direction. The segregation coefficient increases with electric field. In addition, preliminary results on the cellular instability in this system show that the capillary length of the pattern also increases with electric field. To our knowledge, this is the first binary system with continuously tunable segregation coefficient and capillary length.

Depression and demoralization: phenomenologic differences and research perspectives.

Demoralization may be viewed as a combination of distress and subjective incompetence. The main problem in demoralization is the sense of incompetence experienced by the demoralized individual; this sense of incompetence results from uncertainty as to the appropriate direction of action. By contrast, the major difficulty in endogenomorphic depression is a decreased magnitude of motivation even when the appropriate direction of action is known. This distinction is important not only because demoralization appears to be a major public health problem, but also because subjective incompetence appears to influence the course and worsen the prognosis of both nonpsychiatric and psychiatric disorders.

[The risk approach and maternal mortality: a Latin American perspective]. / El enfoque de riesgo y la mortalidad materna: una perspectiva latinoamericana.

Maternal mortality in Latin America and the Caribbean is a health problem that reflects the existing inequalities in the Region, as expressed in the loss of more than 28,000 women every year as a result of abortions and complications of pregnancy, childbirth, and the puerperium. This situation is associated with the limited coverage and low quality of health and family planning services and, in particular, with the tremendous unmet need for family planning services in many countries of the Region. The risk approach is proposed as an effective method for enhancing health care, especially in the area of maternal and child health. Systematically applied, this method will help to improve reproductive health.

[Overview of the technical international cooperation in health]. / Panorama de la cooperación técnica internacional en salud.

International cooperation in health is a critical input for national development. Available resources in the health sector are scarce and are frequently badly used. For these reasons national and international efforts are required to reorient the delivery of health services. Many of the social and economic problems of the 1980s still subsist, and even though outstanding political changes are evidenced, the war situation unbalanced the global order. Poverty affects almost a quarter of the human population. It is necessary to increase the resources appointed to the social sector, particularly those devoted to health and nutrition programmes. Technical exchange between countries has increased considerably since its origins at the beginning of the century. The present international cooperation in health is based on the analysis of the countries health situation and health services within the global socio-economic and political framework; it concentrates efforts around social and epidemiological priorities; considers man as central axle for development and encourages social participation in health. International technical cooperation is also giving increasing attention to environmental problems, rising new pathologies, to the promotion of scientific research and to the development of adequate technology for each national situation.

Conditions not attributable to a mental disorder: an epidemiological study of family problems.

OBJECTIVE: The objective of this research was to identify and measure the differences among three groups of psychiatric outpatients: those with family problems but without mental disorders, those with both family problems and mental disorders, and those with a mental disorder but without family problems. DSM-III V code conditions (conditions not attributable to a mental disorder) other than family problems do occur, but family problems were chosen because of their importance. METHOD: All patients admitted to an outpatient psychiatric clinic during a 2-year period were studied (N = 382). Of these, 92 had V code conditions unrelated to family problems and were excluded. Data are presented on the remaining 290 patients. Sociodemographic variables, DSM-III diagnoses, source of referral, previous and subsequent use of outpatient services, and type of family problem were examined. Patients were from a low-income population and came from three ethnic groups (white, black, and Hispanic). RESULTS: Among whites, more men than women had family problems without mental disorders; among blacks, more women than men had family problems with and without mental disorders. Marital problems occurred most frequently in the group with family problems without mental disorders, and married subjects were more likely to have a V code condition. Professional referrals were more common than other referral sources in all three groups. However, family problems without mental disorders were more likely to occur among those who were referred by their families and had never had psychiatric treatment; patients with family problems and mental disorders were more likely to be self-referred and to have been previously treated; those with a mental disorder but without family problems were usually referred by professionals and almost always had been previously treated. There appeared to be underreporting of family problems among those with family problems and mental disorders and among black men with family problems with and without mental disorders. CONCLUSIONS: More research is needed on the patterns of use of outpatient psychiatric services by individuals with family problems and other V code conditions.

Prediction of use of psychiatric services: application of the CART (classification and regression trees) algorithm.

A computerized recursive partitioning program called Classification and Regression Trees (CART) was used to identify potential high users of services among low-income psychiatric outpatients. Sociodemographic variables, clinical variables (e.g., psychiatric diagnosis and type of presenting complaint), source of referral and the most recent psychiatric treatment setting used were studied. Discharge from inpatient psychiatric treatment right before admission to outpatient psychiatric treatment was found to be the most consistent, the most powerful and the only necessary predictor of high use of outpatient psychiatric services.

The relationship of presenting complaints to the use of psychiatric services in a low-income group.

The presenting complaints of 503 subjects who contacted a mental health clinic serving an inner-city, low-income group were classified into mental state, physical functioning, social relations, and social performance. The authors examined the relationship between type of presenting complaint and race ethnicity, gender, age, marital status, DSM-III diagnosis, source of referral, and previous use of psychiatric services. Diagnostic group, source of referral, previous use of services, and type of presenting complaint were the four best predictors of number of outpatient visits. The increment in prediction produced by type of presenting complaint, however, was relatively modest.

Transmission studies from blood of Alzheimer disease patients and healthy relatives.

The etiology of Alzheimer disease (AD) is unknown. To investigate the transmissibility of AD, the buffy coat of the blood from 11 relatives of AD patients, including 2 with suspicious or early signs of AD, was inoculated intracerebrally into hamsters. In these pilot experiments, 5 individuals produced histologically documented spongiform encephalopathy on primary passage in recipient hamsters. Material from 3 of these positives was serially transmitted in a second passage. The histological alterations observed in the brains of positive hamsters were similar to those seen in experimental Creutzfeldt-Jakob disease (CJD). These transmission results raise the intriguing possibility that CJD-like agents may be involved in at least some forms of AD.