Desertification

IPCC SPECIAL REPORT ON CLIMATE CHANGE AND LAND (SRCCL) Chapter 3: Climate Change and Land: An IPCC special report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystem

Quality assurance in stereotactic radiosurgery/radiotherapy according to DIN 6875-1

The new DIN (' Deutsche Industrie- Norm') 6875- 1, which is currently being finalised, deals with quality assurance ( QA) criteria and tests methods for linear accelerator and Gamma Knife stereotactic radiosurgery/ radiotherapy including treatment planning, stereotactic frame and stereotactic imaging and a system test to check the whole chain of uncertainties. Our existing QA program, based on dedicated phantoms and test procedures, has been refined to fulfill the demands of this new DIN. The radiological and mechanical isocentre corresponded within 0.2 mm and the measured 50% isodose lines were in agreement with the calculated ones within less than 0.5 mm. The measured absorbed dose was within 3%. The resultant output factors measured for the 14-, 8- and 4- mm collimator helmet were 0.9870 +/- 0.0086, 0.9578 +/- 0.0057 and 0.8741 +/- 0.0202, respectively. For 170 consecutive tests, the mean geometrical accuracy was 0.48 +/- 0.23 mm. Besides QA phantoms and analysis software developed in- house, the use of commercially available tools facilitated the QA according to the DIN 6875- 1 with which our results complied. Copyright (C) 2004 S. Karger AG, Basel

The problem of motivation of students of the technical university to study chemistry

The article is devoted to studying of a problem of motivation to study chemistry in technical higher educational institutions. Examined the results of testing the peculiarities of the personality of students of the first course. Suggests ways to improve motivation towards learning chemistry

Red Queen Coevolution on Fitness Landscapes

Species do not merely evolve, they also coevolve with other organisms. Coevolution is a major force driving interacting species to continuously evolve ex- ploring their fitness landscapes. Coevolution involves the coupling of species fit- ness landscapes, linking species genetic changes with their inter-specific ecological interactions. Here we first introduce the Red Queen hypothesis of evolution com- menting on some theoretical aspects and empirical evidences. As an introduction to the fitness landscape concept, we review key issues on evolution on simple and rugged fitness landscapes. Then we present key modeling examples of coevolution on different fitness landscapes at different scales, from RNA viruses to complex ecosystems and macroevolution.Comment: 40 pages, 12 figures. To appear in "Recent Advances in the Theory and Application of Fitness Landscapes" (H. Richter and A. Engelbrecht, eds.). Springer Series in Emergence, Complexity, and Computation, 201

Estimating Conservation Needs for Rangelands Using USDA National Resources Inventory Assessments

This study presents (1) the overall concept of assessing non-federal western rangeland soil loss rates at a national scale for determining areas of vulnerability for accelerated soil loss using USDA Natural Resources Conservation Service (NRCS) National Resources Inventory (NRI) data and the Rangeland Hydrology and Erosion Model (RHEM) and (2) the evaluation of a risk-based vulnerability approach as an alternative to the conventional average annual soil loss tolerance (T) for assessment of rangeland sustainability. RHEM was used to estimate runoff and soil loss at the hillslope scale for over 10,000 NRCS NRI sample points in 17 western states on non-federal rangelands. The national average annual soil loss rate on non-federal rangeland is estimated to be 1.4 ton ha⁻¹ year⁻¹. Nationally, 20% of non-federal rangelands generate more than 50% of the average annual soil loss. Over 29.2 × 10⁶ ha (18%) of the non-federal rangelands might benefit from treatment to reduce 1559-1570 soil loss to below 2.2 ton ha⁻¹ year⁻¹. National average annual soil loss rates combine areas with low and accelerated soil loss. Evaluating data in this manner can misrepresent the magnitude of the soil loss problem on rangelands. Between 23% and 29% of U.S. non-federal rangelands are vulnerable to accelerated soil loss (≥ 2.2 ton ha⁻¹ event⁻¹) if assessed as a function of vulnerability to a runoff event with a return period of ≥ 25 years. The NRCS has not evaluated potential soil loss risk in national reports in the past, and adaptation of this technique will allow the USDA and its partners to be proactive in preventing accelerated soil loss on rangelands.Keywords: Soil erosion, Rangeland Hydrology and Erosion Model, Non-federal rangelands, Conservation Effects Assessment Project, Soil loss tolerance, Soil and water conservation, National resources inventor

How do “mental health professionals” who are also or have been “mental health service users” construct their identities?

“Mental health professionals” are increasingly speaking out about their own experiences of using mental health services. However, research suggests that they face identity-related dilemmas because social conventions tend to assume two distinct identities: “professionals” as relatively socially powerful and “patients” as comparatively powerless. The aim of this study was, through discourse analysis, to explore how “mental health professionals” with “mental health service user” experience “construct” their identity. Discourse analysis views identity as fluid and continually renegotiated in social contexts. Ten participants were interviewed, and the interviews were transcribed and analyzed. Participants constructed their identity variously, including as separate “professional” and “patient” identities, switching between these in relation to different contexts, suggesting “unintegrated” identities. Participants also demonstrated personally valued “integrated” identities in relation to some professional contexts. Implications for clinical practice and future research are explored. Positive identity discourses that integrate experiences as a service user and a professional included “personhood” and insider “activist,” drawing in turn on discourses of “personal recovery,” “lived experience,” and “use of self.” These integrated identities can potentially be foregrounded to contribute to realizing the social value of service user and other lived experience in mental health workers, and highlighting positive and hopeful perspectives on mental distress

Hydrologic responses of shortgrass prairie ecosystems

Runoff hydrographs from 3 separate rainfall simulation runs at 11 different shortgrass prairie sites were evaluated to determine the hydrologic similarity within a single ecosystem at widely separated sites. There were no consistent patterns in the equilibrium runoff among sites and simulator runs. When the sites were stratified by soil type, there were differences in time-to-peak of the runoff event and the regression slope of the rising limb of the runoff ratios. Spearman's rank correlation showed no relation of the rising limb slope regression coefficient to measured vegetative characteristics across all sites. There was minimal correlation between the runoff regression coefficient and the percent cover and bare soil. Differences in the biotic components of the sites were not useful in predicting runoff characteristics. If equilibrium runoff was the measured hydrologic response, the sites were dissimilar. Using the time-to-peak and slope of the rising limb components of the runoff hydrograph, the sites were similar on the same soil type. The technique of comparing components of the runoff hydrograph, other than equilibrium runoff has promise to allow one to quickly compare responses among ecosystems to determine if they have similar hydrological functions. Our study on shortgrass prairie sites indicated that easily estimated factors such as biomass, cover and litter were not good indicators of hydrologic function. Also, it is necessary to identify which portion of the runoff event is most important in the assessment. Future hydrologic and erosion models need to develop nonlinear prediction equations to estimate infiltration rates as a function of cover, biomass, and soil properties and also to stratify soils into functional units to accurately estimate runoff rates.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202