Spin-filter effect of the europium chalcogenides: An exactly solved many-body model

A model Hamiltonian is introduced which considers the main features of the experimental spin filter situation as s-f interaction, planar geometry and the strong external electric field. The proposed many-body model can be solved analytically and exactly using Green functions. The spin polarization of the field-emitted electrons is expressed in terms of spin-flip probabilities, which on their part are put down to the exactly known dynamic quantities of the system. The calculated electron spin polarization shows remarkable dependencies on the electron velocity perpendicular to the emitting plane and the strength of s-f coupling. Experimentally observed polarization values of about 90% are well understood within the framework of the proposed model.Comment: accepted (Physical Review B); 10 pages, 11 figures; http://orion.physik.hu-berlin.de

Monitoring and Assessment of Aquatic Life in the Kaskaskia River for Evaluating IDNR Private Lands Programs: Phase II Final Report

Objectives for this monitoring effort facilitate assessment of CREP stream goals by evaluating physicochemical and biological trends in relation to conservation practices and providing technical support to the IDNR CREP. There were four main objectives for Phase II. Objective 1: Continue established monitoring program that provides a basin-wide assessment of status and trends for aquatic life in wadeable streams of the Kaskaskia River basin. Phase I resulted in three years of survey information at locations along a gradient of conservation program land cover, and Phase II continued this survey effort to monitor temporal trends and enhance assessment of spatial patterns. Objective 2: Expand sampling efforts in focal reaches to better characterize biological assemblages and physicochemical habitats of the four subbasins. Strategic selection of survey locations and additional measures of biotic response will aid assessment of CREP goals by evaluating a gradient of possible physicochemical and biological patterns relative to conservation practices. Objective 3: Conduct additional monitoring of key aquatic species populations within the Kaskaskia River basin. Response to conservation practices may differ among stream taxa, and employing additional biological measures for species that may be sensitive to conservation impacts provides opportunity for enhanced analytical resolution. Objective 4: Provide technical support for IDNR’s Private Lands Programs. INHS staff will assist the IDNR by managing spatial data, developing a process for prioritizing lands for reaching CREP goals and coordinating with State and Federal agencies that interact with Illinois CREP.Illinois Department of Natural Resources, Office of Resource Conservationunpublishednot peer reviewedOpe

Frequency, course and correlates of alcohol use from adolescence to young adulthood in a Swiss community survey

BACKGROUND: Few studies have analyzed the frequency of alcohol use across time from adolescence to young adulthood and its outcome in young adulthood. A Swiss longitudinal multilevel assessment project using various measures of psychopathology and psychosocial variables allowed for the study of the frequency and correlates of alcohol use so that this developmental trajectory may be better understood. METHOD: Alcohol use was studied by a questionnaire in a cohort of N = 593 subjects who had been assessed at three times between adolescence and young adulthood within the Zurich Psychology and Psychopathology Study (ZAPPS). Other assessment included questionnaire data measuring emotional and behavioural problems, life events, coping style, self-related cognitions, perceived parenting style and school environment, and size and efficiency of the social network. RESULTS: The increase of alcohol use from early adolescence to young adulthood showed only a few sex-specific differences in terms of the amount of alcohol consumption and the motives to drink. In late adolescence and young adulthood, males had a higher amount of alcohol consumption and were more frequently looking for drunkenness and feeling high. Males also experienced more negative consequences of alcohol use. A subgroup of heavy or problem drinkers showed a large range of emotional and behavioural problems and further indicators of impaired psychosocial functioning both in late adolescence and young adulthood. CONCLUSION: This Swiss community survey documents that alcohol use is problematic in a sizeable proportion of youth and goes hand in hand with a large number of psychosocial problems

Psychosocial adaptation of adolescent migrants in a Swiss community survey

OBJECTIVE: The aim of this study was to compare psychosocial adaptation in adolescent (first generation) migrants, double-citizens (mainly second generation with one migrant parent), and native Swiss, and to compare migrants from various European regions. METHOD: Data from a community survey were based on 1,239 participants (mean age 13.8, SD = 1.6 years) with 996 natives, 55 double-citizens, and 188 migrants. The adolescents completed the youth self-report measuring emotional and behavioural problems, and various questionnaires addressing life events, personality variables, perceived parental behaviour (PPB), family functioning, school environment, and social network. RESULTS: Adolescent migrants had significantly higher scores for internalizing and externalizing problems. There was a pattern of various unfavourable psychosocial features including life events, coping, self-related cognitions, and PPB that was more common among adolescent migrants than natives. Double-citizens were similar to natives in all domains. Young adolescents from South and South-East Europe differed from natives in terms of more unfavourable psychosocial features. Migrant status was best predicted by adverse psychosocial features rather than emotional and behavioural problems. CONCLUSION: There is some indication that certain migrant adolescents are at risk of psychosocial mal-adaptation. Obviously, ethnic origin is an important moderator

Die psychische Befindlichkeit übergewichtiger Kinder

OBJECTIVE: Numerous studies based on parent questionnaires reveal that obese children are subject to both physical and psychosocial strains. Children are not included as informants in the assessment procedure, and there is a lack of clinical interview studies assessing DSM-IV-based diagnoses in overweight children. METHODS: Emotional and behavioural problems of treatment seeking obese children (N = 59; aged 8-12-years) attending a mental health service were assessed by means of clinical interviews (Kinder-DIPS) that included child and parent reports. In addition, Child Behavior Checklist (CBCL) data (N = 55) available for this clinical sample were compared with data of a representative sample of normal-weight children (N = 1,080). Furthermore, CBCL data of the clinical subsample of 10-12 year-old overweight children (N = 34) were compared with data of a subsample of 10-12 year-old overweight children (N = 33) and of the subsample of normal-weight (N = 386) children from a representative population, both matched by sex. RESULTS: 23 children (39%) met full criteria for a psychiatric disorder according to DSM-IV, and 19 (34.5%), nearly one third, suffered from Binge Eating Disorder (BED). The overweight clinical sample and their normal weight peers differed significantly on 6 of the 8 primary syndrome scales, on the internalizing and the externalizing scores, and on the total problem score of the CBCL. The overweight children in the clinical sample scored significantly higher than the overweight children in the representative sample on the subscale measuring social problems and the total score, with BMI accounting for the difference in total score. Within the representative sample, overweight 10-12 year-old children scored significantly higher than their normal weight peers on two scales measuring delinquency and social problems. CONCLUSION: A third of the obese children had mental disorders and behaviour problems. This finding applies to clinically referred obese children and, to a much lesser degree, to nonclinical obese subgroups in the normal population. Clinically obese children constitute a patient group that is in urgent need of multimodal treatment. As a consequence, a major change in treatment and prevention of childhood obesity is warranted, i.e., from the mere treatment of eating and activity behaviours to the inclusion of treatment of co-morbid mental disorder and prevention of chronification

Performance evaluation of nitrogen isotope ratio determination in marine sediments: an inter- laboratory intercomparison

Nitrogen isotopes of organic matter are increasingly studied in marine biogeochemistry and geology, plant and animal ecology, and paleoceanography. Here, we present results of an inter-laboratory test on determination of nitrogen isotope ratios in marine and lacustrine sediments. Six different samples covering a wide range of total nitrogen content and δ15N values were analyzed by eight different laboratories using their routine procedures. The laboratories were asked to measure three batches with three replicates for each sample to assess accuracy and variability within and among laboratories; this permits assessment of repeatability and reproducibility, which are essential in meta analysis of the increasing database on δ15N values in marine sediments. The grand average δ15N values for individual samples ranged from 1.65-10.90‰. One laboratory exhibited an average bias of -0.27‰ compared to the mean of all other laboratories. Apart from one sample, which showed an exceptionally high overall standard deviation (OSD) of 0.51‰, the analytical precision (1 s) averaged 0.24‰, ranging from 0.18-0.31‰ for individual samples. Out of the eight participating laboratories, two showed a significantly elevated within-laboratory standard deviation (WLSD) of 0.41‰ and 0.32‰ compared to an average WLSD of 0.15‰ for the other laboratories. The WLSD was inversely correlated with the ratio of peak height to peak width, which was taken as a simple measure of peak shape. Moreover, our data also revealed an inverse correlation between total nitrogen content and measurement precision. These correlations may provide guidance for improving the measurement precision of individual laboratories. Based on the results of this round robin test, we have estimated the expanded measurement uncertainty on the 2σ level to 0.45‰ for sediment samples with a nitrogen content >0.07 wt%. Sediment samples with lower nitrogen contents cannot be measured with sufficient precision without additional precautions and care should be taken when interpreting δ15N signatures and records for sediments with nitrogen concentrations <0.07 wt%. © 2009 Elsevier Ltd. All rights reserved.status: publishe

Performance evaluation of nitrogen isotope ratio determination in marine and lacustrine sediments: An inter-laboratory comparison

Nitrogen isotopes of organic matter are increasingly studied in marine biogeochemistry and geology, plant and animal ecology, and paleoceanography. Here, we present results of an inter-laboratory test on determination of nitrogen isotope ratios in marine and lacustrine sediments. Six different samples covering a wide range of total nitrogen content and δ15N values were analyzed by eight different laboratories using their routine procedures. The laboratories were asked to measure three batches with three replicates for each sample to assess accuracy and variability within and among laboratories; this permits assessment of repeatability and reproducibility, which are essential in meta analysis of the increasing data base on δ15N values in marine sediments. The grand average δ15N values for individual samples ranged from 1.65–10.90‰. One laboratory exhibited an average bias of –0.27‰ compared to the mean of all other laboratories. Apart from one sample, which showed an exceptionally high overall standard deviation (OSD) of 0.51‰, the analytical precision (1s) averaged 0.24‰, ranging from 0.18–0.31‰ for individual samples. Out of the eight participating laboratories, two showed a significantly elevated within-laboratory standard deviation (WLSD) of 0.41‰ and 0.32‰ compared to an average WLSD of 0.15‰ for the other laboratories. The WLSD was inversely correlated with the ratio of peak height to peak width, which was taken as a simple measure of peak shape. Moreover, our data also revealed an inverse correlation between total nitrogen content and measurement precision. These correlations may provide guidance for improving the measurement precision of individual laboratories. Based on the results of this round robin test, we have estimated the expanded measurement uncertainty on the 2s level to 0.45‰ for sediment samples with a nitrogen content > 0.07% by weight. Sediment samples with lower nitrogen contents cannot be measured with sufficient precision without additional precautions and care should be taken when interpreting δ15N signatures and records for sediments with nitrogen concentrations lower than 0.07% by weight.

Effect of polymer brush architecture on antibiofouling properties

Contains fulltext : 91751.pdf (publisher's version ) (Open Access)4 p