Diagnosing pure-electron plasmas with internal particle flux probes.

Techniques for measuring local plasma potential, density, and temperature of pure-electron plasmas using emissive and Langmuir probes are described. The plasma potential is measured as the least negative potential at which a hot tungsten filament emits electrons. Temperature is measured, as is commonly done in quasineutral plasmas, through the interpretation of a Langmuir probe current-voltage characteristic. Due to the lack of ion-saturation current, the density must also be measured through the interpretation of this characteristic thereby greatly complicating the measurement. Measurements are further complicated by low densities, low cross field transport rates, and large flows typical of pure-electron plasmas. This article describes the use of these techniques on pure-electron plasmas in the Columbia Non-neutral Torus (CNT) stellarator. Measured values for present baseline experimental parameters in CNT are phi(p)=-200+/-2 V, T(e)=4+/-1 eV, and n(e) on the order of 10(12) m(-3) in the interior.

Experimental confirmation of stable, small-debye-length, pure-electron-plasma equilibria in a stellarator.

The creation of the first small-Debye length, low temperature pure electron plasmas in a stellarator is reported. A confinement time of 20 ms has been measured. The long confinement time implies the existence of macroscopically stable equilibria and that the single particle orbits are well confined despite the lack of quasisymmetry in the device, the Columbia non-neutral torus. This confirms the beneficial confinement effects of strong electric fields and the resulting rapid E x B rotation of the electrons. The particle confinement time is presently limited by the presence of bulk insulating materials in the plasma, rather than any intrinsic plasma transport processes. A nearly flat temperature profile is seen in the inner part of the plasma.

A medical needle drive for the study of interstitial implant mechanics.

We describe the construction and test performance of a computer-controlled medical needle drive. The drive represents one facet of a larger project whose aim is to investigate experimentally the mechanics of needle introduction in radioactive 'seed' prostate implants, with a view to identifying ways of making incremental improvements in needle placement accuracy. It is capable of mimicking a range of motions imparted to a needle by a clinical practitioner, and of monitoring the compressive force at the needle tip in real time via an in-line load cell. Tests involving driving needles into porcine gelatin samples using a variety of velocity profiles confirm intended operation. The drive will permit us to introduce needles in a controlled and reproducible manner into a realistic prostate phantom currently being designed.

[Psychosocial resources, transitory events and quality of life of aging people.]. / Ressources psychosociales, événements transitoires et qualité de vie des personnes vieillissantes.

Based on data of the Québec longitudinal study on aging, this article examines crosswise the relation between psychosocial resources of elderly people and their quality of life. The sample of 781 subjects includes three groups of elderly people selected according to their age and their experience or not of a major transitory event: retirement (60-65), widowed (70-75) and functional incapacity (80-85). The results confirm that respondents with a high level of psychosocial resources obtain better performances in the various indexes of quality of life. However, in regards to events, the protective effect of psychosocial resources on quality of life is only shown with those people in retirement. We notice that with people with functional incapacity, social support seem to slightly contribute in maintaining quality of life. Finally, the authors propose certain explanations.

[Incidence of the onset of disability and recovery of functional autonomy among the very old after one year]. / Incidence à un an de l'entrée en incapacité et de la récupération de l'autonomie fonctionnelle chez les octogénaires.

BACKGROUND: This article measures the survival rate and explores the changes in functional autonomy among both men and women over a one-year period in a sample of 272 subjects aged 80-85. METHODS: Data were taken from the Quebec Longitudinal Study on Aging, a multi-cohort prospective study focusing on health and quality of life. The sample comprises two sub-groups, namely disabled and autonomous subjects. Eligible participants were selected from the Quebec Health Insurance Plan (QHIP) file. However, to obtain the required number of participants, the sample was completed from eligible subjects who volunteered in response to TV, billboard and newspaper advertising about the project. The Functional Autonomy Measurement System (SMAF) was used to assess disability. The SMAF assesses functional disability in 5 domains: activities of daily living (ADL), mobility, instrumental activities (IADL), communication, and mental functioning. RESULTS: After one year, nearly 5% of the subjects had died and 72.5% were still autonomous, i.e., they had a score under 4.5 on the SMAF. The annual incidence of the onset of disability (including death, lengthy hospitalization, functional incapacities and cognitive deficits) was 20%. However, no difference was found between the sexes in regard to the risk of losing autonomy. The main areas where disability occurred among the previously autonomous subjects were, in order of importance, domestic tasks, mobility and communication. The study confirmed that it is possible to recover autonomy, even at this advanced age, particularly for women (11.2%), but less so for men (3.6%). CONCLUSION: This phenomenon of recovering functional autonomy suggests that octogenarians have a residual potential and confirms the effectiveness of preventive and curative measures and the benefits of interventions by community and family networks.

Stressful life events and psychological distress of the very old: does social support have a moderating effect?

The purpose of this paper was to examine whether social support has a moderating effect on the relationship between exposure to stressful life events and psychological distress. To test this, 224 men and women aged 81-86 were sampled from two municipal regional counties: Sherbrooke (and vicinity) and Trois-Rivières, in the Province of Quebec, Canada. The French version of the Geriatric Scale of Recent Life Events, the Psychiatric Symptom Index, and the Social Provision Scale were used. Multiple regression analyses revealed that social support did not cancel out the deleterious effect of life events on the outcome measure. The negative aspect of social interaction may explain why social support did not have a protective effect. Also, social isolation resulting from psychological distress could reduce the opportunity for instrumental help and emotional support.

[Global health indicators as predictors of mortality in elderly persons: a six-year prospective study]. / Les indices de santé globale comme prédicteurs de la mortalité chez les personnes âgées: une étude prospective de six ans.

The objective of this prospective study was to determine if certain global health indicators can predict the occurrence of mortality in a representative sample of the elderly in three age strata, after adjusting for sex. The sample, matched for age and sex, comprised 559 subjects. Structured interviews based on the OARS and SMAF were used to assess health. The cumulative number of deaths per month was then recorded over a six-year period. Cox's multivariate model was used to express the relative mortality risk among these three age cohorts using the overall health indicators as predictors. The results indicate that these indicators are significant predictors of mortality only in the 65-72 age group. Several hypotheses are presented to explain this phenomenon: psychological adjustment to illness, internalization of prevailing social norms, or a cohort and survival effect.

Criterion validity of a new measure of self-actualization.

Many authors have questioned the validity of the major existing measures of self-actualization (the Personal Orientation Inventory, the Personal Orientation Dimensions, and the Short Index of Self-actualization), given their serious theoretical and methodological limitations. A new inventory was developed, the Measure of Actualization of Potential, and various studies were conducted to assess its theoretical and empirical content as well as its construct validity, internal consistency, and temporal reliability. The present aim was to estimate the criterion validity of the new measure using humanistic clinical psychologists' assessments as the criterion. The results show that eight clinical psychologists' rankings of 73 individuals are positively and highly correlated with the scores obtained by the same individuals on the Measure of Actualization of Potential.

Exposure and risk factors among elderly drivers: a case-control study.

To study the risk factors associated with exposure, aging, and other characteristics of elderly drivers, a case-control survey of 557 licensed drivers was conducted among residents of medium-sized, small towns and rural areas in Quebec, Canada. The subjects, aged 68 and over, were selected from the database of the provincial Automobile Insurance Board. The case group was chosen on the basis of performance, either accidents or violations, during the preceding three years. Cases were matched to a control group (blank file for the last three years) on a stratification basis (age, gender, region) in the proportion of two controls for one case. The survey which was conducted through a mail questionnaire achieved a participation rate of nearly 60%. The logistic regression method was used to assess the risk (odds ratios). The results of this study reveal that risk is proportional to the frequency of daily vehicle use or annual kilometrage. The hypothesis that elderly drivers who rarely expose themselves are at more risk is thus rejected. Vulnerable subgroups were the most elderly (> 77), city or suburban residents, the unmarried, and white collars (during active life).

The impact of a support group programme for care-givers on the institutionalisation of demented patients.

Support group programmes have been proposed to alleviate the care-givers' burden and postpone institutionalisation of demented patients. Experimental studies on these programmes failed to detect any impact on care-givers' burden, but none have examined the effect on institutionalisation. The objective of this paper is to assess the impact of a support group programme for care-givers on the institutionalisation of demented patients. Forty-five care-givers of community-dwelling demented patients were allocated randomly to the study group (n = 24) and the control group (n = 21). Subjects in the study group attended a structured programme of 8 weekly sessions of 3 h each. Subjects assigned to the control group were referred to the informal monthly meetings of the Alzheimer's Society. Using survival analysis, the median length of time until institutionalisation was 30 months from the time of the entry into the study. At 24 months, the probability of being institutionalised was 0.33 in the study group and 0.45 in the control group. This difference was not statistically significant (log-rank test: chi2 = 1.02; P = 0.31). These results emphasize the lack of scientific evidence about efficacy of such programmes and the need for a large multi-centre study on this topic.

Efficacy of a support group programme for care-givers of demented patients in the community: a randomized controlled trial.

Dementia induces morbidity not only in the patients but also in the families taking care of them. Many studies described the impact of care-giving on physical and psychological health. Support groups were designed to alleviate the burden of care-givers. The objective of this study was to measure the efficacy of a support group programme for care-givers of demented patients in the community. Forty-one primary care-givers were randomly assigned to a study (n=23) or a control group (n=18). Subjects of the study group attended a structured programme of eight 2-h sessions. These weekly sessions consisted of information on the disease, role-playing on management of behavior problems, discussion on emotional impact of care-giving, and learning of stress management techniques. Subjects of the control group were referred to informal monthly meetings of the Alzheimer's Society. Subjects of both groups were evaluated at the entry (T1), after 8 weeks (T2) and after 8 months (T3). The outcome variables were the Burden Interview, the Revised Memory and Behavior Problems Checklist, the Brief Symptoms Inventory, the Alzheimer's Disease Knowledge Test and a questionnaire on health care utilization. Compared with the control group, subjects of the study group yielded only a significant increase in knowledge about the disease (p<0.0001) but no significant difference on the other outcome variables. It is concluded that this type of support group programme seems to have only a minimal impact on morbidity and on the burden of care-givers. These results are similar with two other studies examining the same issue.

[Lung function and gastroesophageal reflux during chronic bronchitis (author's transl)]. / Fonction respiratoire et reflux gastro-oesophagien au cours de la bronchite chronique.

The coexistence of gastroesophageal reflux (GER) and respiratory diseases has led us to raise three questions : 1) how frequent is GER in patients with chronic bronchitis?, 2) is the respiratory function in patients with chronic bronchitis different when they have a GER and when they do not?, 3) is the GER different in patients with chronic bronchitis and in subjects not suffering with chronic bronchitis? The study of esophageal pH after a test meal showed there was a GER in 29 out of the 47 patients studied. The measurements of lung volume, air flow, pulmonary compliance, as well as the alveolo-capillary transfer of carbon monoxide, showed that there was no difference in the lung function of bronchitics whether they had a reflux or not. On the other hand, refluxes are less frequent but longer in patients having bronchitis and a GER, than in those having a GER but not having bronchitis. This must be linked to a low esophageal clearance which could be related to the attack of bronchitis. Only a well carried out prospective study of the treatment of GER in patients will reveal if the reflux increases bronchitic symptoms.

Effect of ranitidine on resting pressure and pentagastrin response of human lower esophageal sphincter.

The effect on the lower esophageal sphincter pressure (LESP) of a new H2-receptor antagonist, ranitidine, has been tested during manometry in normal man. Basal tone and LES pentagastrin response were not significantly different after oral ranitidine administration in 10 healthy subjects. No significant variation of LESP was observed in six additional patients during 1 mg/kg body wt ranitidine infusion as compared to placebo. These results show that despite the difference in chemical structure and a greater inhibitory effect on gastric secretion, ranitidine, like cimetidine, does not alter resting pressure or LES response to pentagastrin in man. Ranitidine may therefore benefit patients with gastroesophageal reflux.

Esophageal motility and pulmonary function in progressive systemic sclerosis.

In order to evaluate the influence of esophageal dysfunction on lung function abnormalities in progressive systemic sclerosis (PSS), we compared pulmonary function tests in 24 patients with PSS according to esophageal motility. We observed three groups of subjects with normal esophageal motility (8 cases), impaired peristalsis but normal lower esophageal sphincter (LES; 7 cases), and impaired peristalsis and LES function (9 cases). Dynamic lung compliance was significantly lower in patients with impaired peristalsis and LES function than in the two other groups, suggesting that a gastroesophageal reflux (GER) could enhance pulmonary fibrosis in PSS.

[Effect of protein and energy intake on nitrogen metabolism of undernourished patients on continuous enteral nutrition]. / Influence des apports protéiques et énergétiques sur le bilan azoté de malades dénutris alimentés par voie entérale continue.

Nitrogen balance, energy balance and respiratory quotient were measured in 18 undernourished patients fed with continuous enteral nutrition in order to assess the effects of: a) various levels of protein and energy intakes with a fixed diet composition; b) energy/nitrogen ratio; c) proportions of carbohydrates in energy intake. The results were the following: 1) With energy intakes from 4,880 to 8,360 kJ/m2/day (protein: 18 p. 100) nitrogen balance and net protein absorption were significantly correlated with nitrogen intake (respectively P less than 0.01 and P less than 0.001). 2) Nitrogen balance was not significantly different whether the patient received normo (energy/nitrogen = 476 kJ/g) or hypernutrition ( energy /nitrogen = 1,056 kJ/g). 3) Nitrogen balance was not different in 6 patients receiving the same energy and nitrogen intakes but 80 or 55 p. 100 carbohydrates; high carbohydrates diet induced lipid synthesis. These results confirm the value of continuous enteral nutrition to positive nitrogen balance in undernourished patients. Except when energy expenditure level is very high they do not support a policy of routinely use hypernutrition with high carbohydrates diet.