Helium-4 solid-liquid interface mobility and ultrasonic energy absorption mechanisms

The first measurements of acoustic reflection, together with acoustic transmission at the solid-liquid interface of⁴He, are used to determine the total relative acoustic energy absorption at the interface as a function of temperature. Based on these results, a new mechanism for the temperature dependence of the kinetics of growth and interface mobility is proposed.     

Structure of a High Efficiency Glass Fiber Filter Medium

ABSTRACT

The analysis of the real internal structure of a high efficiency glass fiber filter medium was carried out to provide detailed structure data, e.g., for more realistic calculations of the filter performance. The procedure of the structure analysis is described in detail and the most important results are presented and discussed. The fiber diameter distribution was found to be constant throughout the HEPA medium studied. The fibers tended to be oriented perpendicular to the direction of air flow, but there was no preferred direction of orientation within the plane of the filter medium. The interfiber distance distributions in parallel as well as in perpendicular orientation to air flow direction were found to be of the expected exponential shape for distances > 1 μm. On the other hand, the frequencies of the distances < 1 μm increase and the exponential shape of the curves is no longer observed.     

Memory-delineated subtypes of schizophrenia: Relationship to clinical, neuroanatomical, and neurophysiological measures.

Memory performance was examined in patients with schizophrenia to determine whether subgroups conforming to cortical and subcortical dementias could be identified and, if so, whether subgroups differed on clinical, neuroanatomical, and neurophysiological measures. A cluster analysis of California Verbal Learning Test performance classified patients into 3 subgroups. Two groups exhibited memory deficits consistent with the cortical-subcortical distinction, whereas 1 group was unimpaired. Cortical patients tended to be male, and they had earlier illness onset, reduced temporal lobe gray matter, and hypometabolism. Subcortical patients had ventricular enlargement and more negative symptoms. Unimpaired patients had fewer negative symptoms and dorsal medial prefrontal hypermetabolism. The authors conclude that categorizing patients on the basis of memory deficits may yield neurobiologically meaningful disease subtypes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Controlled and automatic processing during animal word list generation in schizophrenia.

Controlled and automatic aspects of semantic-associative functioning in schizophrenia were investigated by evaluating performance on animal word list generation (WLG). Responses from control (n?=?47) and patient (n?=?38) participants were subjected to multidimensional scaling (MDS), cluster analysis (CA), and indices on the basis of number of shared attributes (SA) between consecutive responses. Patient MDS results accounted for less variance and contained more error than control data. CA results yielded fewer and less clear animal-response subgroups among patients yet demonstrated intact associations among strongly related exemplars. The SA indices revealed better clustering and more effective switching among response clusters in controls than patients. Results suggest that animal WLG in schizophrenia is compromised both by aberrant automatic semantic-associative network activation and by controlled processes such as search, access, and selection. This pattern is consistent with prominent frontotemporal pathology evident in the disorder. (PsycINFO Database Record (c) 2010 APA, all rights reserved)