Hermetic compressors — a case study

Since the energy crisis, Danfoss have been working systematically on their hermetic compressors for household refigerators and freezers. Significant savings in energy consumption have been achieved, both from improvements to existing designs and from a new design of the smallest compressors.The improvements and results achieved are presented here.     

Attention-related effects on somatosensory evoked potentials in college students at high risk for psychopathology.

Determined whether a deviation from normal amplitude in the evoked potential in response to attention directed to a stimulus would occur in 10 undergraduates with high scores on a measure of physical anhedonia (AN) and 9 undergraduates with a high score on a measure of perceptual aberration (PA). Ss were compared with 10 control undergraduates and 7 schizophrenics (mean age 25.6 yrs). Previous studies have shown low amplitudes for schizophrenics. Somatosensory evoked potentials (SEPs) were recorded from 5 scalp locations while Ss counted stimuli to 1 of 4 randomly stimulated fingers; SEPs to counted stimuli contained the attention-related late positive wave (P400). P400 amplitudes of AN Ss were lower than those of normal controls, whereas P400 amplitudes of PA Ss and their matched controls did not differ. P400 amplitudes of AN Ss did not differ significantly from those of schizophrenics, although AN means were somewhat higher. P400 amplitude may provide information that is different from the associated behavioral response and a more sensitive indication of central mechanism dysfunction. (40 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A comparison of polydipsia prevalence among chronic psychiatric patients using three measurement approaches

Many previous prevalence studies of polydipsia (PD) have utilized single and often non-biologic measures. In this study we estimated prevalence using specific gravity of urine (SPGU), normalized diurnal weight gain (NDWG), and staff identification (staff ID). Agreement between these two biologic and one behavioral measure was assessed. A total of 572 psychiatric inpatients were assessed for SPGU and NDWG. Unit staff were asked to identify PD patients. Positive and negative PD groups were formed separately based on the SPGU, NDWG, and staff ID data. All three measures were collected on the same day. Prevalence data for the biologic measures varied. The estimate for PD by SPGU (< 1.009 cutoff) was higher (43.4% of sample) than that of NDWG (> 2.5%; 25.4%) or staff ID (21.4%). These prevalence rates did not change substantially after exclusion of medical causes of polyuria. Agreement, assessed by the kappa statistic, was uniformly low among the measures. Weak association between the measures reflects their multidetermined, nonspecific nature, and highlights the lack of a diagnostic standard in the field. The observed prevalence rates must be considered rough approximations. Associations between the measures and certain subject characteristics suggest the measures may identify different types of potential PD patients. These different types of patients are discussed, as are other issues in the measurement of PD. The data suggest estimates of PD are a function of the type of measure used as even biologic measures vary greatly.