Validation of numerical codes for impact and explosion cratering: Impacts on strengthless and metal targets

Over the last few decades, rapid improvement of computer capabilities has allowed impact cratering to be modeled with increasing complexity and realism, and has paved the way for a new era of numerical modeling of the impact process, including full, three-dimensional (3D) simulations. When properly benchmarked and validated against observation, computer models offer a powerful tool for understanding the mechanics of impact crater formation. This work presents results from the first phase of a project to benchmark and validate shock codes. A variety of 2D and 3D codes were used in this study, from commercial products like AUTODYN, to codes developed within the scientific community like SOVA, SPH, ZEUS-MP, iSALE, and codes developed at U.S. National Laboratories like CTH, SAGE/RAGE, and ALE3D. Benchmark calculations of shock wave propagation in aluminum-on-aluminum impacts were performed to examine the agreement between codes for simple idealized problems. The benchmark simulations show that variability in code results is to be expected due to differences in the underlying solution algorithm of each code, artificial stability parameters, spatial and temporal resolution, and material models. Overall, the inter-code variability in peak shock pressure as a function of distance is around 10 to 20%. In general, if the impactor is resolved by at least 20 cells across its radius, the underestimation of peak shock pressure due to spatial resolution is less than 10%. In addition to the benchmark tests, three validation tests were performed to examine the ability of the codes to reproduce the time evolution of crater radius and depth observed in vertical laboratory impacts in water and two well-characterized aluminum alloys. Results from these calculations are in good agreement with experiments. There appears to be a general tendency of shock physics codes to underestimate the radius of the forming crater. Overall, the discrepancy between the model and experiment results is between 10 and 20%, similar to the inter-code variability.The Meteoritics & Planetary Science archives are made available by the Meteoritical Society and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202

Corporate social responsibility: The disclosure-performance gap

As increased stakeholder pressure requires companies to be transparent about their CSR practices, it is essential to know how reliable corporate disclosure mechanisms are, testing the gap between corporate social responsibility claims and actual practice. This study benchmarks corporate social responsibility policies and practices of ten international hotel groups of particular importance to the European leisure market. We found that corporate systems are not necessarily reflective of actual operations, environmental performance is eco-savings driven, labour policies aim to comply with local legislation, socio-economic policies are inward looking with little acceptance of impacts on the destination, and customer engagement is limited. Generally larger hotel groups have more comprehensive policies but also greater gaps in implementation, while the smaller hotel groups focus only on environmental management and deliver what they promised. As the first survey of its kind in tourism, both the methodology and the findings have implications for further research. © 2012 Elsevier Ltd

Suicide and self-harm related internet use:a cross-sectional study and clinician focus groups

Abstract. Background: The rise in Internet use adds a new dimension to suicide prevention. We investigated suicide/self-harm (S/Sh)-related Internet use among patients presenting to hospital with self-harm. Method: We asked 1,198 adult and 315 child and adolescent patients presenting to hospital following self-harm in a city in South West England about Internet use associated with their hospital presentation. Associations between Internet use and sociodemographic and clinical characteristics were investigated using multivariable logistic regression models. Focus groups with clinicians explored the acceptability and utility of asking about Internet use. Results: The prevalence of S/Sh-related Internet use was 8.4% (95% CI: 6.8–10.1%) among adult hospital presentations and 26.0% (95% CI = 21.3–31.2%) among children's hospital presentations. In both samples, S/Sh-related Internet use was associated with higher levels of suicidal intent. Mostly, clinicians found it acceptable to ask about Internet use during psychosocial assessments and believed this could inform perceptions of risk and decision-making. Limitations: It is unclear whether the findings in this study are applicable to the general self-harm patient population because only those who had psychosocial assessments were included. Conclusion: S/Sh-related Internet use is likely to become increasingly relevant as the Internet-native generation matures. Furthermore, Internet use may be a proxy marker for intent. </jats:p

Biophysical characterization of protected areas globally through optimized image segmentation and classification

Protected areas (PAs) need to be assessed systematically according to biodiversity values and threats in order to support decision-making processes. For this, PAs can be characterized according to their species, ecosystems and threats, but such information is often difficult to access and usually not comparable across regions. There are currently over 200,000 PAs in the world, and assessing these systematically according to their ecological values remains a huge challenge. However, linking remote sensing with ecological modelling can help to overcome some limitations of conservation studies, such as the sampling bias of biodiversity inventories. The aim of this paper is to introduce eHabitat+, a habitat modelling service supporting the European Commission's Digital Observatory for Protected Areas, and specifically to discuss a component that systematically stratifies PAs into different habitat functional types based on remote sensing data. eHabitat+ uses an optimized procedure of automatic image segmentation based on several environmental variables to identify the main biophysical gradients in each PA. This allows a systematic production of key indicators on PAs that can be compared globally. Results from a few case studies are illustrated to show the benefits and limitations of this open-source tool

Modelling Shear Flows with SPH and Grid Based Methods

Given the importance of shear flows for astrophysical gas dynamics, we study the evolution of the Kelvin-Helmholtz instability (KHI) analytically and numerically. We derive the dispersion relation for the two-dimensional KHI including viscous dissipation. The resulting expression for the growth rate is then used to estimate the intrinsic viscosity of four numerical schemes depending on code-specific as well as on physical parameters. Our set of numerical schemes includes the Tree-SPH code VINE, an alternative SPH formulation developed by Price (2008), and the finite-volume grid codes FLASH and PLUTO. In the first part, we explicitly demonstrate the effect of dissipation-inhibiting mechanisms such as the Balsara viscosity on the evolution of the KHI. With VINE, increasing density contrasts lead to a continuously increasing suppression of the KHI (with complete suppression from a contrast of 6:1 or higher). The alternative SPH formulation including an artificial thermal conductivity reproduces the analytically expected growth rates up to a density contrast of 10:1. The second part addresses the shear flow evolution with FLASH and PLUTO. Both codes result in a consistent non-viscous evolution (in the equal as well as in the different density case) in agreement with the analytical prediction. The viscous evolution studied with FLASH shows minor deviations from the analytical prediction.Comment: 16 pages, 17 figure

Indicators for Assessing Habitat Values and Pressures for Protected Areas—An Integrated Habitat and Land Cover Change Approach for the Udzungwa Mountains National Park in Tanzania

Assessing the status and monitoring the trends of land cover dynamics in and around protected areas is of utmost importance for park managers and decision makers. Moreover, to support the Convention on Biological Diversity (CBD)’s Strategic Action Plan including the Aichi Biodiversity Targets, such efforts are necessary to set a framework to reach the agreed national, regional or global targets. The integration of land use/cover change (LULCC) data with information on habitats and population density provides the means to assess potential degradation and disturbance resulting from anthropogenic activities such as agriculture and urban area expansion. This study assesses the LULCC over a 20 year (1990–2000–2010) period using freely available Landsat imagery and a dedicated method and toolbox for the Udzungwa Mountains National Park (UMNP) and its surroundings (20 km buffer) in Tanzania. Habitat data gathered from the Digital Observatory for Protected Areas (DOPA)’s eHabitat+ Web service were used to perform ecological stratification of the study area and to develop similarity maps of the potential presence of comparable habitat types outside the protected area. Finally, integration of the habitat similarity maps with the LULCC data was applied in order to evaluate potential pressures on the different habitats within the national park and on the linking corridors between UMNP and other protected areas in the context of wildlife movement and migration. The results show that the UMNP has not suffered from relevant human activities during the study period. The natural vegetation area has remained stable around 1780 km2. In the surrounding 20 km buffer area and the connecting corridors, however, the anthropogenic impact has been strong. Artificially built up areas increased by 14.24% over the last 20 years and the agriculture area increased from 11% in 1990 to 30% in the year 2010. The habitat functional types and the similarity maps confirmed the importance of the buffer zone and the connecting corridors for wildlife movements, while the similarity maps detected other potential corridors for wildlife

Accountability for the Rights of People with Psychosocial Disabilities: An Assessment of Country Reports for the Convention on the Rights of Persons with Disabilities.

The Convention on the Rights of Persons with Disabilities (CRPD) has been identified as a milestone in human rights protection, offering people with psychosocial disabilities the opportunity to hold their governments accountable for the realization of their rights. To facilitate such accountability, the country reports produced under the CRPD reporting process should adequately reflect these persons' experiences and relevant positive or negative developments in the country. Our study used content analysis to review the extent and quality of reporting related to mental health and psychosocial disabilities in 19 country reports. The criteria used were based on provisions of the CRPD and on priorities identified by a steering committee of people with psychosocial disabilities. We found a wide variation in the quantity and quality of states' reporting, with an indication that this variation relates to countries' economic development. Increasing the participation of representative organizations of people with psychosocial disabilities is needed for state parties to fulfill their reporting obligations. While there has been progress in improving organizations of persons with disabilities capacity to be heard at the global level, our findings suggest low levels of participation in CRPD processes at the national level in many countries. State parties must actively include these groups to ensure implementation of the CRPD principles

Responding to the Call: Building a Training Program to Diversify the Academy in Alzheimer’s Disease Research

Alzheimer\u27s disease and related dementias (ADRD) are at the forefront of the United States (US) public health agenda due to their tremendous human and financial burden. Further, disproportionately high ADRD rates among racial/ethnic minorities require incorporating the unique perspectives of racially and ethnically diverse scientists, which will necessitate diversifying the scientific workforce that investigates disparities in aging. The purpose of this paper is to describe the training and mentorship initiatives of the National Institute on Aging (NIA)-funded Carolina Center on Alzheimer\u27s Disease and Minority Research, emphasizing lessons learned from our engagement with underrepresented minority and minoritized (URM) Scientists. We highlight three aims of the Center\u27s training and mentorship component: (1) Fund pilot projects for URM Scientists conducting research on sociocultural, behavioral, and environmental factors that influence ADRD-related health disparities; (2) Provide mentorship to build the research capacity of Center Scientists; and (3) Offer research education in Health Disparities and Minority Aging Research to Center Scientists and interested researchers at all partner institutions. Our experience may be a practical resource for others developing interdisciplinary training programs to increase the pipeline of URM Scientists conducting ADRD research

C9orf72-ALS human iPSC microglia are pro-inflammatory and toxic to co-cultured motor neurons via MMP9

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by progressive motor neuron loss, with additional pathophysiological involvement of non-neuronal cells such as microglia. The commonest ALS-associated genetic variant is a hexanucleotide repeat expansion (HRE) mutation in C9orf72. Here, we study its consequences for microglial function using human iPSC-derived microglia. By RNA-sequencing, we identify enrichment of pathways associated with immune cell activation and cyto-/chemokines in C9orf72 HRE mutant microglia versus healthy controls, most prominently after LPS priming. Specifically, LPS-primed C9orf72 HRE mutant microglia show consistently increased expression and release of matrix metalloproteinase-9 (MMP9). LPS-primed C9orf72 HRE mutant microglia are toxic to co-cultured healthy motor neurons, which is ameliorated by concomitant application of an MMP9 inhibitor. Finally, we identify release of dipeptidyl peptidase-4 (DPP4) as a marker for MMP9-dependent microglial dysregulation in co-culture. These results demonstrate cellular dysfunction of C9orf72 HRE mutant microglia, and a non-cell-autonomous role in driving C9orf72-ALS pathophysiology in motor neurons through MMP9 signaling