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Notes: Detailed analysis of recent high beta discharges in the DIII-D [Plasma Physics Controlled Nuclear Fusion Research, 1986 (International Atomic Energy Agency, Vienna, 1987), Vol. I, p. 159] tokamak demonstrates that the resistive vacuum vessel can provide stabilization of low n magnetohydrodynamic (MHD) modes. The experimental beta values reaching up to βT=12.6% are more than 30% larger than the maximum stable beta calculated with no wall stabilization. Plasma rotation is essential for stabilization. When the plasma rotation slows sufficiently, unstable modes with the characteristics of the predicted "resistive wall'' mode are observed. Through slowing of the plasma rotation between the q=2 and q=3 surfaces with the application of a nonaxisymmetric field, it has been determined that the rotation at the outer rational surfaces is most important, and that the critical rotation frequency is of the order of Ω/2π=1 kHz. © 1995 American Institute of Physics.

Notes: Experiments to explore the long-time evolution of noninductive, high βp plasmas in the DIII-D tokamak [Plasma Physics and Controlled Nuclear Fusion Research, 1986 (International Atomic Energy Agency, Vienna, 1987), Vol. 1, p. 159], have identified a new, quiescent, high performance regime. The experiments were carried out at low current (400–800 kA) with medium power neutral beam injection (3–10 MW). This regime is characterized by high q0 ((approximately-greater-than)2) and moderate li(∼1.3). It is reached by slow relaxation of the current profile, on the resistive time scale. As the profiles relax, q0 rises and li falls. When q0 goes above 2 (approximately), magnetohydrodynamic (MHD) activity disappears, and the stored energy rises. Most dramatic is the strong peaking of the central density, which increases by as much as a factor of 2. The improved central confinement appears similar to the PEP/reversed central shear/second stable core modes seen in tokamak experiments, but in this case without external intervention or transient excitation. At high current, a similar, but slower relaxation is seen. Also notable in connection with these discharges is the behavior of the edge and scrape-off layer (SOL). The edge localized modes (ELM's) as seen previously, are small and very rapid (to 1 kHz). The SOL exhibits high density (≥1×1019 m−3), which shows little or no falloff with radius. Also the power deposition at the divertor surface is very broad, up to four times the width usually seen. This regime is of particular interest for the development of steady-state tokamak operating scenarios, for the Tokamak Physics Experiment (TPX), and following reactors.

Notes: It is shown that the theoretical predictions and experimental observations of toroidicity-induced Alfvén eigenmodes (TAE's) are now in good agreement, with particularly detailed agreement in the mode frequencies. Calculations of the driving and damping rates predict the importance of continuum damping for low toroidal mode numbers and this is confirmed experimentally. However, theoretical calculations in finite-β, shaped discharges predict the existence of other global Alfvén modes, in particular the ellipticity-induced Alfvén eigenmode (EAE) and a new mode, the beta-induced Alfvén eigenmode (BAE). The BAE mode is calculated to be in or below the same frequency range as the TAE mode and may contribute to the experimental observations at high β. Experimental evidence and complementary analyses are presented confirming the presence of the EAE mode at higher frequencies.

Notes: Uncontrolled studies of avoidance of house dust mite (Dermatophagoides pteronyssinus) by atopic subjects have reported clinical improvement in the severity of eczema. The aim of the present study was to examine the temporal relationship between environmental exposure to the major mite allergen (Der pI) and clinical disease severity in children with chronic atopic eczema. Twelve children were identified as being house dust mite-sensitive on the basis of skin prick test and RAST to Der pI. They were examined on two occasions with a median interval of 63 days. Clinical severity of eczema improved in nine children and deteriorated in two children during this period. Der pI concentration in dust from mattresses changed significantly in only three subjects and there was no correlation between changes in clinical severity and changes in environmental Der pI exposure. Change in RAST against Der pI did correlate positively with change in Der pI exposure (rho=0.56, P〈0.05) but these changes were not associated significantly with changes in eczema severity or skin test response to Der pI. It is concluded that the observed changes in clinical severity were unlikely to be due to immediate hypersensitivity responses to natural variations in Der pI concentrations in the personal environments of these subjects.

Notes: Abstract This study compared demographic and diagnostic characteristics of a sample of homeless outpatient mental health clinic attenders with a domiciled comparison group from the same clinic. Data on demographic variables and DSM-III-R psychiatric diagnoses were collected over a two-year period on a consecutive sample of 166 homeless and 117 nonhomeless clinic attenders. Data on demographics and psychiatric diagnoses of the homeless clinic attenders were further compared with data collected systematically from 900 homeless individuals in the same city. In the clinic, homeless subjects were more often members of ethnic minorities, and homeless women were significantly younger and better educated than their nonhomeless counterparts. Rates of schizophrenia, bipolar disorder, and somatization disorder were not significantly different between homeless and nonhomeless groups. Major depression was about four times as prevalent in nonhomeless men as in homeless men. Homeless men were significantly more likely than nonhomeless men to quality for a diagnosis of alcohol use disorder, and homeless women were more likely than other women to qualify for a diagnosis of drug use disorder. Both homeless men and women were significantly more likely than their domiciled counterparts to meet criteria for antisocial personality disorder. Personality disorder other than antisocial was more prevalent in nonhomeless men than in homeless men. Combined rates of personality disorder were significantly higher among homeless than nonhomeless women, but not men. Homeless clinic attenders were demographically and diagnostically very similar to a general homeless population in the same city. The only diagnosis that was more prevalent in the homeless clinic than in the homeless community was antisocial personality disorder. We concluded that because of differences in diagnostic prevalence, homeless and nonhomeless individuals in mental health clinics need to be considered independently. Clinicians treating homeless outpatients may benefit from having special facility in diagnosis and management of antisocial personality disorder and substance abuse, along with expertise in other psychiatric disorders in this population.

Notes: Abstract Assessment of psychiatric disorders encounters unique complexities in homeless populations. Although the use of structured diagnostic instruments has significantly improved research methodology in this area, questions remain about the validity of using cross-sectional diagnostic methods derived from studies of more general populations. In particular, the validity of structured diagnostic instruments in the assessment of schizophrenia, depression, drug use disorder, and antisocial personality disorder (ASPD) in homeless populations has been questioned. The purpose of this study was to examine the association of psychiatric diagnoses with the weather. It was hypothesized that self-report of psychiatric illness may be affected by prevailing weather conditions. Nine hundred homeless subjects randomly sampled from St. Louis shelters, day centers, and unsheltered locations were interviewed over a 1-year period. Official average daily temperature and amount of precipitation on the day of each subject's interview were compared with lifetime and current psychiatric diagnoses ascertained by the Diagnostic Interview Schedule. Similar analyses were performed in general population data from the Epidemiologic Catchment Area study. The study found that among homeless men, inclement weather on the day of interview was associated with lifetime and current diagnoses of major depression, lifetime drug use disorder, lifetime diagnosis of ASPD, and current alcohol use disorder. These findings, however, were not present in homeless women and not reflected in the general population. The results, although limited, suggest that weather may confound cross-sectional, standardized methods of psychiatric diagnosis in homeless men. Weather-related factors among homeless men are associated with ascertainment of both lifetime and current diagnosis of major depression, as well as lifetime drug use disorder and ASPD and current alcohol use disorder. Possible interpretations of these findings are discussed, with implications for intervention strategies for psychiatric disorders in the larger context of homelessness and social problems. “Rainy days and Mondays always get me down...” The Carpenters, 1971