Suchergebnisse

Recent literature on no-till is reviewed with particular emphasis on research on commercial uptake and environmental concerns in northern, western and south-western Europe. Increased interest in no-till, and minimum or reduced tillage, results from changes in the economic circumstances of crop production, the opportunity to increase the area of more profitable autumn-sown crops and increased concern about environmental damage associated with soil inversion by ploughing. Highly contrasting soil and climate types within and between these regions exert a strong influence on the success of no-till. While no-till may often result in crop yields which equal or exceed those obtained after ploughing, modest reductions in yield may be tolerated if production costs are lower than with ploughing. The relative costs of fuel and herbicides have changed appreciably in recent years making no-till more attractive commercially. While effective weed control is an essential aspect of no-till, current herbicide technology may not yet fully achieve this. In northern regions no-till usually allows earlier drilling of winter-sown crops but will give lower soil temperature and higher moisture content in spring, causing delayed drilling of spring-sown crops. Notill soils have greater bulk density and bearing capacity than ploughed soils with a pronounced vertical orientation of macroporosity allowing penetration of roots and water, especially in view of the increased population of deep-burrowing earthworms. Particular care must be taken with no-till to minimise soil damage at harvest and to ensure the even distribution of crop residues prior to drilling. Reduced erosion and runoff after adoption of no-till are widely observed and are of particular importance in southwestern Europe. No-till reduces losses of phosphorus in runoff and, in some cases, reduces the loss of nitrate through leaching. Emissions of greenhouse gases CO2 and N2O from no-till soils are highly variable and depend on complex interactions of soil properties. Emission of CO2 from fuel during machinery usage is always appreciably reduced with no-till. Increased soil organic carbon in surface layers of no-till soils is widely found but may not be associated with increased carbon sequestration throughout the profile. The evaluation of the relative carbon balance for no-till and ploughing depends upon complex inter-relationships between soil and climate factors which are as yet poorly understood. Adoption of no-till could be encouraged by government financial assistance in recognition of environmental benefits, although future restrictions on the use of herbicides may be a deterrent. Opportunities for further research on no-till are outlined. 2011 Elsevier B.V. All rights reserved.

16‐17 July 2010, International AIDS Society's Workshop "Towards a Cure": HIV Reservoirs and Strategies to Control Them, Vienna, Austria

Amines and other nitrogen-containing compounds, due to their electron donor character, can form excited state emissive complexes in systems that comprise an electron acceptor. Sulphur-containing heteroaromatic compounds such as phenoxathiin are also well-known for their electron donor character. Starting from these two considerations, we aimed at finding exciplexes in which the electron donor contains sulphur. We studied several D-A pairs in solvents of different polarity and found out that the system phenoxathiin-thioxanthone presents a new emission band at longer wavelength than the D and A bands in non-polar solvents, which is quenched in polar ones. In order to explain the exciplex formation, which is determined by an electron transfer process, the standard free enthalpy for the latter was calculated according to the Rehm-Weller equation. The equilibrium constants and the activation barrier for the exciplex formation were determined as well from steady-state emission data at different donor concentrations and at different temperatures, respectively.

The aim of this work was to investigate the possibilities of the solvent free synthesis of Schiff base (azomethyne) from terephthalaldehyde and p-aminophenol. The pure compounds and the reaction product were studied by differential scanning calorimetry (DSC), FTIR spectroscopy, UV-Vis spectroscopy and adiabatic combustion calorimetry. The structure of the reaction product was determined by FTIR spectroscopy. Spectral studies have shown that the reaction product is formed in a single stage. The standard enthalpy of reaction was obtained from heat of combustion of reactants and products and their value shows that the reaction is exothermic.

7‐11 November 2010, Tenth International Congress on Drug Therapy in HIV Infection, Glasgow, UK

Background Conduct, anxiety, and depressive disorders account for over 75% of the adolescent mental health burden globally. The current protocol will test a low-intensity problem-solving intervention for school-going adolescents with common mental health problems in India. The protocol also tests the effects of a classroom-based sensitization intervention on the demand for counselling services in an embedded recruitment trial. Methods/design We will conduct a two-arm, individually randomized controlled trial in six Government-run secondary schools in New Delhi. The targeted sample is 240 adolescents in grades 9–12 with persistent, elevated mental health symptoms and associated distress/impairment. Participants will receive either a brief problem-solving intervention delivered over 3 weeks by lay counsellors (intervention) or enhanced usual care comprised of problem-solving booklets (control). Self-reported adolescent mental health symptoms and idiographic problems will be assessed at 6 weeks (co-primary outcomes) and again at 12 weeks post-randomization. In addition, adolescent-reported distress/impairment, perceived stress, mental wellbeing, and clinical remission, as well as parent-reported adolescent mental health symptoms and impact scores, will be assessed at 6 and 12 weeks post-randomization. We will also complete a parallel process evaluation, including estimations of the costs of delivering the interventions. An embedded recruitment trial will apply a stepped-wedge, cluster (class)-randomized controlled design in 70 classes across the six schools. This will evaluate the added effect of a classroom-based sensitization intervention over and above school-level sensitization activities on the primary outcome of referral rate into the host trial. Other outcomes will be the proportion of referrals eligible to participate in the host trial, proportion of self-generated referrals, and severity and pattern of symptoms among referred adolescents in each condition. Power calculations were undertaken separately for ...

One of the most intensely studied features in the chemistry of nitrosamines is the restricted rotation around the N-N bond and, consequently, the estimation of the energy strain (Estr) determined by the NO group. This is rationalized in terms of the interaction between the electron lone-pairs of the amine nitrogen and the 𝜋 electrons of the –N=O group (nN-πNO* conjugation). Combining the results of DFT calculations on 43 nitrosamines (11 acyclic, 20 mono- and bicyclic and 12 tricyclic) with a multiple linear regression analysis, the paper affords a number of additive increments, which, by appropriate summation, are able to predict with a good accuracy the total energy of the nitroso compound (E) and the energy strain (Estr) values of the –N=O group for any acyclic or cyclic saturated nitrosamines.

© The Author(s) 2014. The aim of this study was to determine optimally efficient cutoff scores on the Posttraumatic Stress Disorder Checklist (PCL) for identifying full posttraumatic stress disorder (PTSD) and partial PTSD (P-PTSD) in active-duty Marines and Sailors. Participants were 1,016 Marines and Sailors who were administered the PCL and Clinician-Administered PTSD Scale (CAPS) 3 months after returning from Operations Iraqi and Enduring Freedom. PCL cutoffs were tested against three CAPS-based classifications: full PTSD, stringent P-PTSD, and lenient P-PTSD. A PCL score of 39 was found to be optimally efficient for identifying full PTSD. Scores of 38 and 33 were found to be optimally efficient for identifying stringent and lenient P-PTSD, respectively. Findings suggest that the PCL cutoff that is optimally efficient for detecting PTSD in active-duty Marines and Sailors is substantially lower than the score of 50 commonly used by researchers. In addition, findings provide scores useful for identifying P-PTSD in returning service members.