Low temperature scattering with the R-matrix method: the Morse potential

Experiments are starting to probe collisions and chemical reactions between atoms and molecules at ultra-low temperatures. We have developed a new theoretical procedure for studying these collisions using the R-matrix method. Here this method is tested for the atom -- atom collisions described by a Morse potential. Analytic solutions for continuum states of the Morse potential are derived and compared with numerical results computed using an R-matrix method where the inner region wavefunctions are obtained using a standard nuclear motion algorithm. Results are given for eigenphases and scattering lengths. Excellent agreement is obtained in all cases. Progress in developing a general procedure for treating ultra-low energy reactive and non-reactive collisions is discussed.Comment: 18 pages, 6 figures, 3 tables, conferenc

Spatial Analyses of Benthic Habitats to Define Coral Reef Ecosystem Regions and Potential Biogeographic Boundaries along a Latitudinal Gradient

Marine organism diversity typically attenuates latitudinally from tropical to colder climate regimes. Since the distribution of many marine species relates to certain habitats and depth regimes, mapping data provide valuable information in the absence of detailed ecological data that can be used to identify and spatially quantify smaller scale (10 s km) coral reef ecosystem regions and potential physical biogeographic barriers. This study focused on the southeast Florida coast due to a recognized, but understudied, tropical to subtropical biogeographic gradient. GIS spatial analyses were conducted on recent, accurate, shallow-water (0–30 m) benthic habitat maps to identify and quantify specific regions along the coast that were statistically distinct in the number and amount of major benthic habitat types. Habitat type and width were measured for 209 evenly-spaced cross-shelf transects. Evaluation of groupings from a cluster analysis at 75% similarity yielded five distinct regions. The number of benthic habitats and their area, width, distance from shore, distance from each other, and LIDAR depths were calculated in GIS and examined to determine regional statistical differences. The number of benthic habitats decreased with increasing latitude from 9 in the south to 4 in the north and many of the habitat metrics statistically differed between regions. Three potential biogeographic barriers were found at the Boca, Hillsboro, and Biscayne boundaries, where specific shallow-water habitats were absent further north; Middle Reef, Inner Reef, and oceanic seagrass beds respectively. The Bahamas Fault Zone boundary was also noted where changes in coastal morphologies occurred that could relate to subtle ecological changes. The analyses defined regions on a smaller scale more appropriate to regional management decisions, hence strengthening marine conservation planning with an objective, scientific foundation for decision making. They provide a framework for similar regional analyses elsewhere

Outcomes of decompression for lumbar spinal canal stenosis based upon preoperative radiographic severity

BACKGROUND: The relationship between severity of preoperative radiographic findings and surgical outcomes following decompression for lumbar degenerative spinal canal stenosis is unclear. Our aim in this paper was to gain insight into this relationship. We determined pre-operative radiographic severity on MRI scans using strict methodological controls and correlated such severity with post-operative outcomes using prospectively collected data. METHODS: Twenty-seven consecutive patients undergoing decompression for isolated degenerative spinal canal stenosis at L4-L5 were included. We measured cross-sectional area on MRI using the technique of Hamanishi. We categorized the severity of stenosis using Laurencin and Lipson's 'Stenosis Ratio'. We determined pre-operative status (prospectively) and post-operative outcomes using Weiner and Fraser's 'Neurogenic Claudication Outcome Score'. We determined patient satisfaction using standardized questionnaires. Each of these is a validated measure. Formal statistical evaluation was undertaken. RESULTS: No patients (0 of 14) with a greater than 50% reduction in cross-sectional area on pre-operative MRI had unsatisfactory outcomes. In contrast, outcomes for patients with less than or equal to 50% reduction in cross-sectional area had unsatifactory outcomes in 6 of 13 cases, with all but one negative outcome having a cross-sectional area reduction between 32% and 47%. CONCLUSION: The findings suggest that there appears to be a relationship between severity of stenosis and outcomes of decompressive surgery such that patients with a greater than 50% reduction in cross sectional area are more likely to have a successful outcome

Hsp90 orchestrates transcriptional regulation by Hsf1 and cell wall remodelling by MAPK signalling during thermal adaptation in a pathogenic yeast

Acknowledgments We thank Rebecca Shapiro for creating CaLC1819, CaLC1855 and CaLC1875, Gillian Milne for help with EM, Aaron Mitchell for generously providing the transposon insertion mutant library, Jesus Pla for generously providing the hog1 hst7 mutant, and Cathy Collins for technical assistance.Peer reviewedPublisher PD

The effects of pesticide mixtures on degradation of pendimethalin in soils

Most agronomic situations involve a sequence of herbicide, fungicide, and insecticide application. On the other hand, use of pesticidal combinations has become a standard practice in the production of many agricultural crops. One of the most important processes influencing the behavior of a pesticide in the environment is its degradation in soil. It is known that due to several pesticide applications in one vegetation season, the pesticide may be present in mixtures with other pesticides or xenobiotics in soil. This study examines the role which a mixture of chemicals plays in pesticide degradation. The influence of other pesticides on the rate of pendimethalin (PDM) degradation in soil was measured in controlled conditions. Mixtures of PDM with mancozeb or mancozeb and thiamethoxam significantly influenced the degradation of pendimethalin under controlled conditions. The second type of mixtures, with metribuzin or thiamethoxam, did not affect the behavior of pendimethalin in soil. Also, we determined the influence of water content on the rate of pendimethalin degradation alone in two soils and compared it to the rate in three pesticide mixtures. We compared two equations to evaluate the predictors of the rate of herbicide dissipation in soil: the first-order kinetic and the non-linear empirical models. We used the non-linear empirical model assuming that the degradation rate of a herbicide in soil is proportional to the difference of the observed concentration of herbicide in soil at time and concentration of herbicide in the last day of measurement

Isolation and characterization of Treponema phagedenis-like spirochetes from digital dermatitis lesions in Swedish dairy cattle

© 2008 Pringle et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

The elderly in the psychiatric emergency service (PES); a descriptive study

<p>Abstract</p> <p>Background</p> <p>The impact of an aging population on the psychiatric emergency service (PES) has not been fully ascertained. Cognitive dysfunctions aside, many DSM-IV disorders may have a lower prevalence in the elderly, who appear to be underrepresented in the PES. We therefore attempted to more precisely assess their patterns of PES use and their clinical and demographic characteristics.</p> <p>Methods</p> <p>Close to 30,000 visits to a general hospital PES (Montreal, Quebec, Canada) were acquired between 1990 and 2004 and pooled with over 17,000 visits acquired using the same methodology at three other services in Quebec between 2002 and 2004.</p> <p>Results</p> <p>The median age of PES patients increased over time. However, the proportion of yearly visits attributable to the elderly (compared to those under 65) showed no consistent increase during the observation period. The pattern of return visits (two to three, four to ten, eleven or more) did not differ from that of patients under 65, although the latter made a greater number of total return visits per patient. The elderly were more often women (62%), widowed (28%), came to the PES accompanied (42%) and reported « illness » as an important stressor (29%). About 39% were referred for depression or anxiety. They were less violent (10%) upon their arrival. Affective disorders predominated in the diagnostic profile, they were less co-morbid and more likely admitted than patients under 65.</p> <p>Conclusion</p> <p>Although no proportional increase in PES use over time was found the elderly do possess distinct characteristics potentially useful in PES resource planning so as to better serve this increasingly important segment of the general population.</p

Parents’ Promotion of Psychological Autonomy, Psychological Control, and Mexican–American Adolescents’ Adjustment

Mexican–American adolescents are at an elevated risk for adjustment difficulties. In an effort to identify parenting practices that can affect the adjustment of Mexican–American youth, the current study examined parents’ promotion of psychological autonomy and parents’ psychological control as perceived by Mexican–American early adolescents, and explored their associations with adolescents’ adjustment in the context of acculturation. In 5th grade, 134 (54.5% female) Mexican–American adolescents reported on their acculturation level and the parenting practices of their mothers and fathers. In 5th and 7th grade, adolescents also reported on their depressive symptoms, number of delinquent friends, and self-worth. Perceptions of promotion of psychological autonomy and of psychological control were positively correlated. However, perceptions of more promotion of psychological autonomy and of less psychological control predicted fewer depressive symptoms 2 years later. Perceptions of more promotion of psychological autonomy also predicted fewer delinquent friends two years later. Finally, perceptions of more promotion of psychological autonomy predicted higher self-worth only among less acculturated adolescents. The study underscores the roles that promotion of psychological autonomy and psychological control may play in Mexican–American children’s well-being during early adolescence

The direction of effects between perceived parental behavioral control and psychological control and adolescents’ self-reported GAD and SAD symptoms

This study examined the direction of effects and age and sex differences between adolescents’ perceptions of parental behavioral and psychological control and adolescents’ self-reports of generalized anxiety disorder (GAD) and separation anxiety disorder (SAD) symptoms. The study focused on 1,313 Dutch adolescents (early-to-middle cohort n = 923, 70.3%; middle-to-late cohort n = 390, 29.7%) from the general population. A multi-group, structural equation model was employed to analyze the direction of the effects between behavioral control, psychological control and GAD and SAD symptoms for the adolescent cohorts. The current study demonstrated that a unidirectional child effect model of the adolescents’ GAD and SAD symptoms predicting parental control best described the data. Additionally, adolescent GAD and SAD symptoms were stronger and more systematically related to psychological control than to behavioral control. With regard to age–sex differences, anxiety symptoms almost systematically predicted parental control over time for the early adolescent boys, whereas no significant differences were found between the late adolescent boys and girls