Twenty years of cognitive assessment: current status and future directions

This commentary examines a number of methodological and conceptual issues that were raised in this special section on cognitive assessment. Although progress has been made in a number of areas since cognitive-clinical researchers first addressed the assessment of cognition almost 20 years ago, important conceptual and methodological questions still remain unresolved. These include questions about the validity of retrospective self-report questionnaires of cognition, the low convergent validity between different assessment methods, and the failure to specify the range of generalizability of specific cognition measures. Further advances in cognitive assessment will depend on a more concerted research focus on the methodological and conceptual issues raised in this special section.     

Genotypic relationships among strains classified under the (Pasteurella) haemolytica-complex as indicated by ribotyping and multilocus enzyme electrophoresis

Two-hundred and one strains classified under the (Pasteurella) haemolytica-complex isolated from cattle, sheep, deer, pigs, hares and rabbits were investigated by ribotyping. Fifty-nine of these strains were selected for further studies using multilocus enzyme electrophoresis (MEE). A correlation between the clusters identified by ribotyping and MEE was demonstrated and the results furthermore indicated that a genetic basis exists for most clusters previously outlined by the use of quantitative evaluation of phenotypic data. The taxonomic relevance of ornithine decarboxylase and fermentation of L-arabinose, D-sorbitol and glucosides for taxonomic delineation within the (P.) haemolytica-complex was supported. A taxonomic importance was further indicated for ONPG, ONPX, ONPF, meso-inositol, D-xylose, maltose, dextrine and NPG in relation to some of the taxa. Within the porcine taxon 15, however, differences in ornithine decarboxylase did not correspond to genetic clusters. Six lineages were revealed by MEE. Lineage A contained electrophoretic types (ETs) representing biogroups 1, 3A-3H, 8A and 9, indicating a genetic relationship between these groups--an observation which was supported by ribotyping. Lineage B included biogroup 8D, 3 strains from biogroup 10 and a single strain from biogroup 1 and taxon 18/biovar 1. Lineage C contained strains allocated to biogroup 6 from ruminants and the porcine taxon 15. The similarity between these two groups was accentuated by ribotyping. Lineage D and the single isolate in lineage E contained strains allocated to biogroups 7, 10, 8B and 8C, in addition to single strains from biogroups 6 and 9. The same strains were found in the heterogenous ribotype cluster 17. Lineage F contained strains representing the leprine taxon 20 and the ruminant (P.) granulomatis. Ribotyping indicated that the ruminant biogroup 3J was affiliated with both taxon 20 and (P.) granulomatis.     

Conductance fluctuations in solids caused by defect migration

Conductance fluctuations caused by defect migration in randomized potential profile within the specimen of solids are considered and the problem of spectrum evaluation is solved. The noise is presented in the time domain as a superposition of local disturbances in the conductance. Each disturbance is a clustered random telegraph signal (RTS). The evaluation of the resulting spectrum is reduced to Lorentzians' summation. The approach suggested is more general compared to the known model of two-level systems (TLS) which considers defect jumps between two selected states. The criteria which are decisive for the shape of the noise spectrum are formulated. Mechanisms of conductance modulation initiated by defect migration are considered in detail. Numerical estimations for the resultant noise magnitude are also presented.     

Interaction of human Arp2/3 complex and the Listeria monocytogenes ActA protein in actin filament nucleation

Actin filament assembly at the cell surface of the pathogenic bacterium Listeria monocytogenes requires the bacterial ActA surface protein and the host cell Arp2/3 complex. Purified Arp2/3 complex accelerated the nucleation of actin polymerization in vitro, but pure ActA had no effect. However, when combined, the Arp2/3 complex and ActA synergistically stimulated the nucleation of actin filaments. This mechanism of activating the host Arp2/3 complex at the L. monocytogenes surface may be similar to the strategy used by cells to control Arp2/3 complex activity and hence the spatial and temporal distribution of actin polymerization.     

Trends in overweight among US adults from 1987 to 1993: a multistate telephone survey

OBJECTIVES: Using data from the Behavioral Risk Factor Surveillance System, this study describes trends in the prevalence of overweight between 1987 and 1993. METHODS: Data were examined from 33 states participating in an ongoing telephone survey of health behaviors of adults (n = 387,704). Self-reported weights and heights were used to calculate sex-specific prevalence estimates of overweight for each year from 1987 to 1993. Time trends were evaluated with the use of linear regression. RESULTS: Between 1987 and 1993, the age-adjusted prevalence of overweight increased by 0.9% per year for both sexes (from 21.9% to 26.7% among men and from 20.6% to 25.4% among women). The increasing linear trend was observed in all subgroups of the population but was most notable for Black men (1.5% per year) and men living in the Northeast (1.4% per year). Secular changes in smoking and leisure-time physical activity did not entirely account for the increase in overweight. CONCLUSIONS: The prevalence of overweight among American adults increased by 5% between 1987 and 1993. Efforts are needed to explore the causes of this adverse trend and to find effective strategies to prevent obesity.     

Assessment of pseudarthrosis in pedicle screw fusion: a prospective study comparing plain radiographs, flexion/extension radiographs, CT scanning, and bone scintigraphy with operative findings

Tribal warfare is a way of life in the highlands of Papua New Guinea. In earlier times direct confrontation with bushknives and axes, and shooting with bows and arrows were common. In recent years there have not been as many instances of direct confrontation with bushknives and axes, but the use of bows and arrows is on the rise. Since 1993, guns have been increasingly used, with devastating results. In 1993, 18 deaths were reported from tribal warfare in one area of the Southern Highlands Province, especially from gunshots, while in 1994, 24 deaths were reported from another area. A five-year review of tribal fight admissions to Mendi Hospital, from 1990 to 1994, showed an increase in the number and proportion of gunshot wounds; there were none in 1990-1992 but they constituted 18% of tribal fight injuries in 1993 and 33% in 1994.     

Immune recognition of viral antigens

The response exhibited by the immune system to viral and other foreign antigens consists of antibody-mediated and T cell-mediated immunity. Structural and molecular biological studies have shown that the antibody response is tailored to provide exquisite specificity by generating binding pockets that are complementary in shape as well as in charge to the antigen. On the other hand, the cellular response uses T-cell receptors (TCRs) and the major histocompatibility complex (MHC) antigens. Structural information on the TCRs is not yet available, but the crystal structures of several MHC class I molecules have shown how one MHC molecule can bind many different peptide sequences that share only the common anchor residue positions that determine allele specificity. MHC class I interactions with the peptide backbone at the N and C termini explain the high specificity of the binding groove for peptide ligands and suggest a universal mode of recognition for peptides to MHC class I molecules. Peptide-MHC class II interactions are less well understood, although recent structural work has shown important differences in the binding clefts of MHC class I and II that lead to longer peptides being bound to class II molecules. Detailed analysis at the molecular level has indicated that conformational changes in both antibodies and MHC molecules occur upon antigen binding.(ABSTRACT TRUNCATED AT 250 WORDS)     

Contribution of the Research and Design Institute of Electrical Technology to the formulation of a strategy for the development of nuclear power in Russia

The results of investigations performed by specialists at Research and Design Institute of Electrical Technology together with other enterprises, institutes, and organizations concerning the formulation of a strategy for the development of nuclear power in Russia in the first half of the 21st century are presented. The individual stages of the work, key assumptions, ideas, and recommendations, on which the strategy is based, the initiatives which the President of the Russian Federation advanced at the millennium summit held at the United Nations, and the international INPRO project initiated by Russia are examined. It is concluded that innovative development and a transition to building as quickly as possible nuclear power objects that meet the requirements and demands of the new century are necessary. __________ Translated from Atomnaya énergiya,Vol. 103, No. 1, pp. 5–15, July, 2007.     

An optimization study on unprogrammed cryopreservation of human CD34+ bone marrow cells and their subsequent storage in an -80 degrees C mechanical freezer

Forty-one patients for whose direct care at least one machine was used and 33 registered nurses from the same five non-critical care units as the patients and from one related unit, participated in a semistructured tape-recorded interview to identify the core categories of the human-machine interface in clinical nursing practice and the relationships between them. Constant comparative analysis was used to organize and process the data. Patients perceived the machines as neutral because of their view of health care and because nurses were the interface between them and the machines. Nurses perceived the machines as either positive or negative, depending on their effect on the nurses' professional competence and the extent to which they worked directly with them.