A new time-kill method of assessing the relative efficacy of antimicrobial agents alone and in combination developed using a representative beta-lactam, aminoglycoside and fluoroquinolone

OBJECTIVE: Previous research has demonstrated the central role of early childhood concentration problems in the development of aggression and other maladaptive behaviors. The present study investigated the moderating effect of concentration problems on the impact of a classroom-based preventive intervention directed at aggressive and shy behaviors in an epidemiologically defined sample of 1,084 urban first-grade children. METHOD: Concentration problems, aggressive behavior, and shy behavior were assessed by a structured teacher interview (the Teacher Observation of Classroom Adaptation-Revised) in the fall and spring of first grade. RESULTS: Children with high ratings on concentration problems in the fall had higher levels of teacher-rated aggressive and shy behavior in the spring than did children without such problems. The intervention reduced aggressive and shy behavior in children regardless of fall concentration level. Boys, but not girls, in the intervention condition with high concentration problems had higher levels of spring aggression than those without such problems, but they also showed the greatest reductions in aggressive behavior from fall to spring. CONCLUSIONS: These results suggest that aggressive behavior is malleable in children with concentration problems, provide further evidence on the etiological significance of concentration problems for the development of maladaptive behavior, and highlight the importance of directly targeting concentration problems to maximize preventive intervention impact.     

The Selective Oxidation of Methanol to Formaldehyde on Iron Molybdate Catalysts and on Component Oxides

The reaction of methanol with an industrial iron molybdate catalyst, and with Fe₂O₃ and with MoO₃, has been investigated with a pulsed flow reactor and temperature-programmed desorption (TPD). The molybdena-based samples show only formaldehyde in TPD as the carbon-containing product, arising from the decomposition of a surface methoxy species. In contrast, haematite yields no formaldehyde, only CO₂ and H₂, which evolve coincidently at 290 °C, and indicates the presence of a formate intermediate on the surface. In turn, the reactor work shows high selectivity to formaldehyde for the molybdate materials and zero for haematite. The iron molybdate sample is more active than the molybdena, conversion beginning at 150 °C for the former and 270 °C for the latter. These data are discussed in terms of a global mechanism for the reaction and a tentative reaction enthalpy profile is proposed. The main differences between the iron and molybdenum samples arise from the stronger binding of oxygen in the former and the higher concentration of cation sites.     

The Manchester heritage

The wider historical and scientific context of the development of computing at the University of Manchester, focusing on the relationship between the University and industry, is described. The role of the National Archive for the History of Computing in preserving this heritage is discussed     

Overview and performance of CCITT/ANSI embedded ADPCM algorithms

Embedded adaptive differential pulse coded modulation (ADPCM) algorithms quantize the differences between the input signal and the estimated signal into core bits and enhancement bits. CCITT Recommendation G.727, which describes embedded ADPCM encoding algorithms with 5, 4, 3, and 2 core bits, is virtually identical to the corresponding ANSI standard T1.310. The main features of G.727 and T1.310 and performance results are presented. A formal subjective evaluation of the speech performance of embedded ADPCM algorithms indicates that a midrise quantizer provides better voice transmission performance than its midtread counterpart when two core bits are used. The subjective data also show that the performance of the 40-kb/s midrise ADPCM algorithm with two feedback bits is indistinguishable from that of 64-kb/s pulse code modulation (PCM) for up to four tandem encodings. Embedded algorithms are therefore recommended for flexible congestion control of integrated traffic in multinode networks     

Influence of myosin heavy chain isoform expression and postmortem metabolism on the ATPase activity of muscle fibers

The objective of this study was to determine the effects of postmortem muscle pH and temperature declines on the actomyosin ATPase activity of muscle fibers expressing different MyHC isoforms. Using a quantitative histochemical procedure to determine ATPase activity, the maximum actomyosin ATPase activity was determined on individual fibers classified by MyHC expression. Samples were collected from the red (RST) and white (WST) semitendinosus muscles at 3 min and 24 h postmortem from electrically stimulated (ES) and control (NS) pork carcasses. In samples taken at 3 min postmortem, type I fibers had the lowest ATPase activity staining and type 2X and 2B had the highest activity staining, with type 2A fibers intermediate. Postmortem time and carcass treatment did not influence the ATPase activity staining of type I muscle fibers. ATPase activity staining of 2A fibers was lower (p<0.001) in 24 h samples than in 3 min samples from ES carcasses. In 3 min and NS-24 h samples, RST type 2A fibers had lower (p<0.05) activities than type 2A fibers from the WST. In type 2X fibers, ATPase activity staining decreased (p<0.01) from 3 min to 24 h postmortem in ES carcasses. This decrease was more severe in WST 2X fibers compared to RST 2X fibers. ATPase activity staining in type 2B fibers did not decrease from 3 min to 24 h postmortem in NS carcasses. In ES carcasses, activity staining of 2B fibers decreased (p<0.0001) with time postmortem. The results of the experiment indicate that fibers expressing fast MyHC isoforms have a higher ATPase activity early postmortem than slow muscle fibers but are more prone to inactivation by a rapid pH decline.     

Information ecology: open system environment for data, memories, and knowing

An information ecology provides a conceptual framework to consider data, the creation of knowledge, and the flow of information within a multidimensional context. This paper, reporting on a 1 year project to study the heterogeneity of information and its management within the Long Term Ecological Research (LTER) community, presents some manifestations of traditionally unreported ‘invisible work’ and associated elements of informal knowledge and unarticulated information. We draw from a range of ethnographic materials to understand ways in which data-information-knowledge are viewed within the community and consider some of the non-linear aspects of data-knowledge-information that relate to the development of a sustained, robust, persistent infrastructure for data collection in environmental science research. Taking data as the unit of study, the notion of long-term research and data holdings leads to consideration of types of memory and of knowledge important for design of cyberinfrastructures. Complexity, ambiguity, and nonlinearity are part of an information ecology and addressed today by exploring multiple types of knowledge, developing information system vocabularies, and recognizing the need for intermediation.     

Two-dimensional oxide catalysts: propene oxidation on FeSbO4

FeSbO₄ catalysts used for selective propene oxidation/ammoxidation have been examined using a combination of XPS and TPD before and after ammonia reduction. These data indicate that the surface has a thin skin which is enriched in antimony oxide. This skin is shown to be important for selective oxidation. This two-dimensional oxide covering can be reduced to metallic antimony after only low pressure treatment in ammonia and the metallic layer can be desorbed upon heating above 600 K. The remaining surface is then covered with an Fe-rich layer which is not so easily reduced, and which is of lower selectivity in partial oxidation to acrolein.