RESUMEN

Tight-binding approaches, especially the Density Functional Tight-Binding (DFTB) and the extended tight-binding schemes, allow for efficient quantum mechanical simulations of large systems and long-time scales. They are derived from ab initio density functional theory using pragmatic approximations and some empirical terms, ensuring a fine balance between speed and accuracy. Their accuracy can be improved by tuning the empirical parameters using machine learning techniques, especially when information about the local environment of the atoms is incorporated. As the significant quantum mechanical contributions are still provided by the tight-binding models, and only short-ranged corrections are fitted, the learning procedure is typically shorter and more transferable as it were with predicting the quantum mechanical properties directly with machine learning without an underlying physically motivated model. As a further advantage, derived quantum mechanical quantities can be calculated based on the tight-binding model without the need for additional learning. We have developed the open-source framework-Tight-Binding Machine Learning Toolkit-which allows the easy implementation of such combined approaches. The toolkit currently contains layers for the DFTB method and an interface to the GFN1-xTB Hamiltonian, but due to its modular structure and its well-defined interfaces, additional atom-based schemes can be implemented easily. We are discussing the general structure of the framework, some essential implementation details, and several proof-of-concept applications demonstrating the perspectives of the combined methods and the functionality of the toolkit.

Asunto(s)

RESUMEN

The interrater reliability of the Psychiatric Research Interview for Substance and Mental Disorders (PRISM) was assessed in a multicentre study. Four sites of the National NeuroAIDS Tissue Consortium performed blinded reratings of audiotaped PRISM interviews of 63 HIV-infected patients. Diagnostic modules for substance-use disorders and major depression were evaluated. Seventy-six per cent of the patient sample displayed one or more substance-use disorder diagnoses and 54% had major depression. Kappa coefficients for lifetime histories of substance abuse or dependence (cocaine, opiates, alcohol, cannabis, sedative, stimulant, hallucinogen) and major depression ranged from 0.66 to 1.00. Overall the PRISM was reliable in assessing both past and current disorders except for current cannabis disorders when patients had concomitant cannabinoid prescriptions for medical therapy. The reliability of substance-induced depression was poor to fair although there was a low prevalence of this diagnosis in our group. We conclude that the PRISM yields reliable diagnoses in a multicentre study of substance-experienced, HIV-infected individuals.

Asunto(s)

RESUMEN

OBJECTIVE: To investigate the correlation between density of nerve fibres and the presence of BDNF(+) cells. METHODS: Densities of nerve fibres and BDNF(+) cells were detected by quantitative immunohistochemistry in fresh synovial tissue from 52 patients with RA, 59 with OA, and 26 controls (Co). BDNF was also detected by in situ hybridisation. RESULTS: Sympathetic nerve fibre density was similar in Co and OA but markedly reduced in RA (p = 0.002), whereas density of substance P positive (SP(+)) sensory nerve fibres was lower in OA than in Co and RA (p = 0.002). The ratio of sympathetic/SP(+) sensory nerve fibre density was highest in OA and Co, followed by RA. The correlation between density of sympathetic nerve fibres and SP(+) sensory nerve fibres in OA (R = 0.425, p = 0.001) was strongly positive, had a positive trend in Co (R = 0.243, NS), but was negative in RA (R = -0.292, p = 0.040). In RA and OA tissue the density of BDNF(+) cells was high in sublining areas but markedly lower in Co (p = 0.001). BDNF(+) cell density correlated positively with the ratio of sympathetic/SP(+) sensory nerve fibre density in Co (R = 0.433, p = 0.045) and in OA (R = 0.613, p = 0.015), but not in RA (R = 0.101, NS). Immunohistochemical double staining demonstrated that some macrophages and fibroblasts were positive for BDNF. CONCLUSIONS: The correlation of density of SP(+) sensory with sympathetic nerve fibres was positive in Co and OA but negative in RA. BDNF may have a stimulatory role on growth of sympathetic in relation to SP(+) sensory nerve fibres in Co and OA, but not in RA.

Asunto(s)

RESUMEN

This study assessed long-term psychosocial sequelae of young adult pediatric burn survivors. Subjects were 101 young adults (43 females and 58 males) between the ages of 18 and 28 years who were at least 2 years (average, 14 years) postburn at least 30% TBSA (mean = 54 +/- 20%). Educational status was 25% high school dropouts, 28% high school graduation only, 32% some college, and 5% completed college. Seventy-seven percent either worked or attended school; 28% had had a long-term partner. When assessed by Achenbach's Young Adult Self-Report (YASR) scale and compared with its published reference group, the males reported differences only in the somatic complaints, but the females endorsed significantly more externalizing and total problems, specifically withdrawn behaviors, somatic complaints, thought problems, aggressive behavior, and delinquent behavior. Despite these problems suffered by some female pediatric burn survivors, the overall outcome revealed that most pediatric burn survivors are making the transition into adulthood with minimal unexpected difficulty.

Asunto(s)

RESUMEN

UNLABELLED: The goal of the study was to examine psychopathology and stressors suffered by suicide victims, and to describe the characteristics of the suicides in the Texas Department of Criminal Justice between June of 1996 to June of 1997. Data on 25 completed suicides were collected from the records department. RESULTS: The authors identified 60% of the suicide victims with a history of psychiatric disorders. Seventy-six percent had been diagnosed with psychiatric disorders while incarcerated. The most frequent psychiatric disorders were mood disorders (64%), psychotic disorders (44%), personality disorders (56%), and comorbidity with a history of presentencing alcohol and drug abuse was common. Most of the victims experienced chronic and/or acute stressors of acute trauma, disrupted relationship, sentence hearing, and/or medical condition. We concluded that important factors associated with increased risk of prison suicide include psychiatric disorders, comorbid substance abuse, a history of suicide attempt, and chronic and/or acute stressors.

Asunto(s)

RESUMEN

Combined homicide-suicides have been classified based on the psychopathology of the perpetrator and the nature of the relationship between perpetrator and victim(s). To further understand the nature of this tragic phenomenon and to test the validity and practicality of a previously suggested classification system, investigators systematically collected data on all combined homicide-suicide events that occurred in Galveston County, Texas over a continuous 18-year period (n = 20). The most common psychopathological finding for perpetrators was high serum alcohol levels that suggested intoxication. Most combined homicide-suicides fell into one of the relational categories and most of these, as predicted, were of the consortial type, possessive subtype. As expected, due to the small sample size, the less common types of combined homicide-suicide were not represented in this sample.

Asunto(s)

RESUMEN

Over the last decade state prisons have experienced unprecedented growth and many demographic changes. At the same time, courts are requiring states to provide mental health screening and treatment to prisoners. Findings from recent studies indicate that the prevalence of mental illness is higher in prisons than in the community, and comorbidity is common. Our ability to generalize from these studies is limited, however, because of major shifts in the demographic mix in prisons during the past decade. New studies on the prevalence of mental illness in prisons, which consider these recent changes would help planners allocate funds and staff to more effectively meet the needs of these individuals.

Asunto(s)

RESUMEN

BACKGROUND: As the elderly population booms and the prevalence of dementia soars, it becomes imperative that primary care physicians recognize early dementia within their own practices. Early recognition and diagnosis of dementia will allow appropriate intervention and treatment to improve morbidity. OBJECTIVE: To examine the most common symptoms associated with early Alzheimer disease (AD), as presented by patients and their families, and to compare these with the recommendations of the "7-Minute Screen" by Solomon et al for the identification of AD and the recommendations of the Agency for Health Care Policy and Research (AHCPR) for the early recognition of dementia. METHODS: A retrospective medical record review was conducted in an outpatient referral population within 2 geriatric evaluation centers. Patient medical record selection was based on Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria for AD, a Mini-Mental State Examination (MMSE) score of 23 or higher, a Geriatric Depression Scale score of less than 5, age above 60 years, and at least an eighth-grade level of education. RESULTS: From 1025 medical records reviewed, 50 patients were chosen who fulfilled all inclusion criteria. Forty patients (80%) missed at least 2, if not all 3, recall items on the MMSE. Thirty patients (60%) had difficulty managing finances and/or balancing a checkbook; 16 (32%) frequently repeated stories and statements; 15 (30%) became lost while driving; 10 (20%) frequently forgot the names of relatives; and 10 (20%) had poor judgment. These results demonstrated a high correlation with recall as a diagnostic factor in diagnosing early AD as found in the 7-Minute Screen. Moreover, these "clues" correlated well with the AHCPR's symptoms that indicate dementia. The symptoms specifically overlapped in the areas of learning and retaining new information (repetition), handling complex tasks (calculation), reasoning ability (judgment), and spatial ability and orientation (driving). CONCLUSIONS: There may be a constellation of symptoms associated with early AD. This constellation includes missing recall items on the MMSE, difficulty in calculation, repetition, getting lost while driving, forgetting the names of relatives, and having poor judgment. Recall is the symptom most consistent with the findings of the 7-Minute Screen in diagnosing AD. However, repetition, calculation, judgment, and driving highly correlate with the AHCPR's dementia symptom checklist. Therefore, if primary care physicians keep this constellation of symptoms in mind while evaluating their geriatric population, they will have greater ability to suspect, diagnose, and treat AD at an early stage. Arch Fam Med. 2000;9:1066-1070

Asunto(s)

RESUMEN

The nosology of chronic depression has become increasingly complex since the publication of the revised third edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-III-R; American Psychiatric Association, 1987), but there are few data available to evaluate the validity of the distinctions between the subtypes of chronic depression. The validity of the distinction between DSM-III-R chronic major depression (CMD) and major depression superimposed on dysthymia (double depression, DD) was examined. Participants were 635 patients with chronic depression in a 12-week trial of antidepressant medications. Patients with CMD, DD, and a 3rd group with a chronic major depressive episode superimposed on dysthymia (DD/CMD) were compared on demographic and clinical characteristics, family history, and response to treatment. Few differences were evident, although the depression of patients with DD/CMD tended to be more severe.

Asunto(s)

Asunto(s)

RESUMEN

Approximately 80% of prison inmates are reported to be functionally illiterate. We hypothesized that poor single word decoding (the chief feature of dyslexia) accounts for a significant percentage of that rate. We studied 253 subjects selected randomly from more than 130,000 Texas prison inmates. Among them, we conducted a cross-sectional sample survey of recently admitted Texas inmates, beginning with social and educational background and followed by an educational test battery that included measures of word attack skill and reading comprehension. Deficient performance was defined primarily as single word decoding performance that measured below the 25th percentile on the Woodcock Reading Mastery Test. We found that 47.8% of the inmates were deficient in word attack skills. Word attack skills were detected in each group defined by gender and ethnicity. Nearly two thirds of the subjects scored poorly in reading comprehension.

Asunto(s)

RESUMEN

OBJECTIVE: To describe the national distribution of child and adolescent psychiatrists by state, community, and youth population. METHOD: Data on child and adolescent psychiatrists were compiled for states and counties and compared by state, county characteristics, number of youth, percentage of youth living in poverty, and child and adolescent psychiatry residents. RESULTS: The number of child and adolescent psychiatrists per 100,000 youth varied greatly by state and county. Child and adolescent psychiatrists were significantly more likely to be located in metropolitan counties and counties with a low percentage of children living in poverty. The distribution of child and adolescent psychiatrists was not significantly related to the distribution of child and adolescent psychiatry residency training programs. CONCLUSIONS: The shortage of child and adolescent psychiatrists is accentuated for nonmetropolitan areas and youth at greatest risk for mental disorders by the current pattern of distribution.

Asunto(s)

RESUMEN

BACKGROUND: The use of self-report screening tests for alcohol use disorders in the primary care setting has been advocated. OBJECTIVE: To test for ethnic and sex bias in three self-report screening tests for alcohol use disorders in a primary care population. DESIGN: Cross-sectional study with patients randomly selected from appointment lists. SETTING: University-based family practice clinic. PATIENTS: Probability sample of 1333 adult family practice patients stratified by sex and ethnicity. MEASUREMENTS: Patients completed 1) a diagnostic interview to determine the presence of a current alcohol use disorder and 2) three screening tests: the CAGE questionnaire, the Self-Administered Alcoholism Screening Test (SAAST), and the Alcohol Use Disorders Identification Test (AUDIT). RESULTS: The areas under the receiver-operating characteristic (ROC) curves for the CAGE questionnaire and the SAAST ranged from 0.61 to 0.88 and were particularly poor for African-American men and Mexican-American women. For the AUDIT, the area under the ROC curves was greater than 0.90 for each patient subgroup. The sensitivity of the CAGE questionnaire and the SAAST at standard cut-points was lowest for Mexican-American women (0.21 and 0.13, respectively). Positive likelihood ratios for the AUDIT were similar to or higher than those for the other screening tests, whereas negative likelihood ratios were lowest for the AUDIT (<0.33), indicating the superiority of this test in ruling out a disorder. CONCLUSIONS: A marked inconsistency in the accuracy of common self-report screening tests for alcohol use disorders was found when these tests were used in a single clinical site with male and female family practice patients of different ethnic backgrounds. The AUDIT does not seem to be affected by ethnic and sex bias.

Asunto(s)

RESUMEN

In our study of a tri-ethnic sample of 2528 junior and high school students, we examined utilization of outpatient mental health services in relation to a number of variables cited in the literature as leading to potential biases and barriers to care. These include: age, gender, ethnicity, socioeconomic status, family size and composition, and linguistic fluency in Hispanic youth. The impact of service availability was examined through differences between the two regions studied: a well-served region of coastal southeast Texas and the markedly under served lower Rio Grande Valley. The impact of symptomatology was evaluated using the total problem score on the Youth Self Report by Achenbach. Hispanic youth had significantly lower mean service utilization than non-Hispanic whites. Multiple regression analyses demonstrated that socioeconomic status and family composition had a greater relative impact on utilization than all other non-clinical factors, both for the total sample as well as for the Hispanic sample. Ethnicity may play a significant role in child mental health services utilization through its close association to socioeconomic status.

Asunto(s)

Asunto(s)

RESUMEN

This study examined the operating characteristics of the Alcohol Use Disorders Identification Test (AUDIT) as a screen for "at-risk" drinking in a multi-ethnic sample of primary care patients, from a family practice center located in the southwestern United States. A probability sample of 1,333 family medicine patients, stratified by gender and racial/ethnic background (white, African-American and Mexican-American) completed the AUDIT, followed by the Alcohol Use Disorders and Associated Disabilities Interview Schedule (AUDADIS) to determine ICD-10 diagnoses. Indicators of hazardous alcohol use and alcohol-related problems were included as measures of "at-risk" drinking. Despite differences in the spectrum of alcohol problems across patient subgroups, there was no evidence of gender or racial/ethnic bias in the AUDIT as indicated by Receiver Operating Characteristic Curve analysis. Excluding abstainers from the analysis and little impact on screening efficacy. In this population, the AUDIT appears to be an unbiased measure of "at-risk" drinking.

Asunto(s)

RESUMEN

A major issue for health reform is the equitable distribution of health services. Equity in the use of services depends in large part on the distribution of need for services, in addition to availability, accessibility, affordability, and acceptability of the services. The present paper focuses on one set of indicators of need, the disability data reported in the 1990 U.S. Census of Population and Housing for 14 southern states. The Census data on work limitation, inability to work, physical mobility, and ability to perform routine personal care show differentials for subpopulations defined by rural versus urban areas within levels of poverty, age, sex, education, and ethnic group. Highest rates of work disability are found for rural, female, elderly, less educated, African-American, and below poverty level populations. The implications of such findings for health care reform suggest that there should be greater access to services by populations of greater identified need. Historically, the opposite has been true, perhaps exacerbating the observed differentials in need.

Asunto(s)

RESUMEN

430 patients participating in the DSM-IV field trial receiving a DSM-III-R SCID-derived diagnosis of episodic major depression (n = 131), dysthymic disorder (n = 37) and double depression (n = 262) completed the social adjustment scale-self-report (Weissman and Bothwell, 1976). Patients with double depression demonstrated greater social morbidity than those suffering from episodic major depression or dysthymic disorder (P < 0.05). Significant predictors of high social morbidity in double depressives included severity of symptoms (P < 0.0001), followed by age of onset of first major depression (P < 0.04). Subscale analysis revealed that double depressives were significantly more impaired in work outside the home and in terms of their financial status (P < 0.05).

Asunto(s)

RESUMEN

A suicide prevention program was implemented at the Galveston County Jail in 1986, reducing the number of suicides to only one from that time until the present. In the ten years prior to the implementation of the program, there had been seven suicides. Nevertheless, there have been a number of cases of medically serious suicide attempts that have occurred since implementation of the program. Thirteen cases of suicide attempts severe enough to warrant transfer to an emergency room for medical attention were identified through jail incident reports as occurring between 1989, when improvements were made in record-keeping at the jail, and July of 1994, when this study was initiated. Hospital records, jail medical records, jail administrative records and, in some cases, competency evaluations were obtained for each case. The cases were examined regarding demographic data, psychiatric history, circumstances surrounding the act, and results of psychiatric evaluation performed after the act. The findings were then compared to studies of suicides and near-suicides in the literature. Examination of these cases has provided information that should render the suicide prevention program even more effective as well as provide useful information to other jails interested in implementing or improving a suicide-prevention program.

Asunto(s)

RESUMEN

The lists of associated symptoms included in the DSM-III, DSM-III-R, and DSM-IV criteria for dysthymic disorder have been criticized for lacking content and discriminant validity. The literature on the content and discriminant validity of dysthymic symptoms was reviewed and relevant data from the DSM-IV Mood Disorders Field Trial were presented. These data indicate that cognitive and social-motivational symptoms are much more characteristic of dysthymic disorder than are vegetative and psychomotor symptoms. In addition, subjects with major depressive disorder exhibit higher rates of most depressive symptoms than do subjects with dysthymic disorder, but there is little evidence of qualitative distinctions in symptomatology between these conditions. Finally, after taking course and exclusion criteria into account, variations in the symptom criteria do not have a major effect on case definition.

Asunto(s)