An experimental evaluation of error seeding as a program validation technique

A previously reported experiment in error seeding as a program validation technique is summarized. The experiment was designed to test the validity of three assumptions on which the alleged effectiveness of error seeding is based. Errors were seeded into 17 functionally identical but independently programmed Pascal programs in such a way as to produce 408 programs, each with one seeded error. Using mean time to failure as a metric, results indicated that it is possible to generate seeded errors that are arbitrarily but not equally difficult to locate. Examination of indigenous errors demonstrated that these are also arbitrarily difficult to locate. These two results support the assumption that seeded and indigenous errors are approximately equally difficult to locate. However, the assumption that, for each type of error, all errors are equally difficult to locate was not borne out. Finally, since a seeded error occasionally corrected an indigenous error, the assumption that errors do not interfere with each other was proven wrong. Error seeding can be made useful by taking these results into account in modifying the underlying model

Study to establish cost predictions for the production of Redox chemicals

The chromium and iron chloride chemicals are significant first costs for NASA Redox energy storage systems. This study was performed to determine the lowest cost at which chromium and iron chlorides could be obtained for a complex of redox energy storage systems. In addition, since the solutions gradually become intermixed during the course of operation of Redox units, it was an objective to evaluate schemes for regeneration of the operating solutions. Three processes were evaluated for the production of chromium and iron chlorides. As a basis for the preliminary plant design and economic evaluation, it was assumed that the plant would produce about 25,000 tons of contained chromium as CrCl3 and an equivalent molar quantity of FeCl2. Preliminary plant designs, including materials and energy balances and sizing of major equipment, were prepared, and capital and operating costs were estimated

Generic metrics and the mass endomorphism on spin three-manifolds

Let $(M,g)$ be a closed Riemannian spin manifold. The constant term in the expansion of the Green function for the Dirac operator at a fixed point $p\in M$ is called the mass endomorphism in $p$ associated to the metric $g$ due to an analogy to the mass in the Yamabe problem. We show that the mass endomorphism of a generic metric on a three-dimensional spin manifold is nonzero. This implies a strict inequality which can be used to avoid bubbling-off phenomena in conformal spin geometry.Comment: 8 page

On a spin conformal invariant on manifolds with boundary

On a n-dimensional connected compact manifold with non-empty boundary equipped with a Riemannian metric, a spin structure and a chirality operator, we study some properties of a spin conformal invariant defined from the first eigenvalue of the Dirac operator under the chiral bag boundary condition. More precisely, we show that we can derive a spinorial analogue of Aubin's inequality.Comment: 26 page

Health impact assessment and climate change: a scoping review

Climate change has various adverse impacts on public health, ranging from heat-related illness to an increased risk of undernutrition in low-income countries. Health impact assessment (HIA) has been advocated as a valuable tool to systematically identify and quantify the effects of climate change on public health and to inform and evaluate the impact of disease-specific adaptation measures as well as health co-benefits of mitigation measures. We conducted a scoping review to map out peer-reviewed literature on HIA in the context of climate change. Web of Science, Scopus and PubMed were searched without language or time restriction. Publications were included in the full text screening that presented or discussed the application of HIA for investigating health impacts of climate change, or associated adaptation and mitigation measures. In total, 76 peer-reviewed publications from 26 countries were included and characterized. There was a paucity of studies on HIA in the context of climate change from low- and middle-income countries. The most investigated climate change effects were related to temperature and air-pollution. Consequently, associated health impacts, such as respiratory or cardiovascular morbidity and mortality, were examined most frequently. Research-driven HIAs with a quantitative methodological approach were the predominant choice to assess health impacts of climate change. Only one in five publications applied a classical step-by-step HIA approach. While quantitative assessment of health impacts associated with climate change seems to be a well established field of research, the few publications applying a step-by-step HIA approach to systematically anticipate potential health impacts of climate change in a given context point at a missed opportunity for strengthening intersectoral collaboration to maximize health (co-) benefits of climate mitigation and adaptation measures. To promote the use of step-by-step HIA in regions that are most affected by climate change, HIA teaching and training efforts are urgently needed

PTH improves titanium implant fixation more than pamidronate or renutrition in osteopenic rats chronically fed a low protein diet

Summary : We evaluated the effects of parathyroid hormone (PTH), pamidronate, or renutrition on osseointegration of titanium implants in the proximal tibia of rats subject to prolonged low-protein diets. PTH improved mechanical fixation, microarchitecture, and increased pull-out strength. Pamidronate or renutrition had lesser effects. PTH can thus improve implant osseointegration in protein-malnourished rats. Introduction: Protein malnutrition impairs implant osseointegration in rats. PTH and pamidronate prevent deleterious effects of protein restriction introduced just prior to implantation. Whether these treatments improve osseointegration after chronic protein deprivation, i.e., in osteopenic bone at time of implantation, is unknown. We evaluated effects of PTH, pamidronate, or renutrition on resistance to pull-out of titanium rods implanted into the rat tibiae following isocaloric low-protein intake. Methods: Forty-one adult female rats received normal or isocaloric low-protein diets. Six weeks later, implants were surgically inserted into proximal tibiae. Following implantation, rats on low-protein diets were treated with PTH (1-34), pamidronate, saline vehicle, or normal protein diets, for another 8weeks. Tibiae were removed for micro-computerised tomographic morphometry and evaluation of pull-out strength. Results: Pull-out strength decreased in rats on isocaloric low-protein diets compared with normal protein group (−33.4%). PTH increased pull-out strength in low-protein group, even compared to controls from the normal protein group. PTH and pamidronate increased bone volume/tissue volume, bone-to-implant contact, and trabecular thickness, whilst trabecular separation was reduced, with a shift to more plate-like bone surrounding the implants. Conclusions: PTH reversed the deleterious effects of long-term protein undernutrition on mechanical fixation and bone microarchitecture and improved implant osseointegration more than pamidronate or renutrition, likely through changes to structure model inde

Snowbeds are more affected than other subalpine-alpine plant communities by climate change in the Swiss Alps

While the upward shift of plant species has been observed on many alpine and nival summits, the reaction of the subalpine and lower alpine plant communities to the current warming and lower snow precipitation has been little investigated so far. To this aim, 63 old, exhaustive plant inventories, distributed along a subalpine-alpine elevation gradient of the Swiss Alps and covering different plant community types (acidic and calcareous grasslands; windy ridges; snowbeds), were revisited after 25 to 50-years. Old and recent inventories were compared in terms of species diversity with Simpson diversity and Bray-Curtis dissimilarity indices, and in terms of community composition with Principal Component Analysis. Changes in ecological conditions were inferred from the ecological indicator values. The alpha-diversity increased in every plant community, likely because of the arrival of new species. As observed on mountain summits, the new species led to a homogenisation of community compositions. The grasslands were quite stable in terms of species composition, whatever the bedrock type. Indeed, the newly arrived species were part of the typical species pool of the colonised community. In contrast, snowbed communities showed pronounced vegetation changes and a clear shift towards dryer conditions and shorter snow cover, evidenced by their colonisation by species from surrounding grasslands. Longer growing seasons allow alpine grassland species, which are taller and hence more competitive, to colonise the snowbeds. This study showed that subalpine-alpine plant communities reacted differently to the on-going climate changes. Lower snow/rain ratio and longer growing seasons seem to have a higher impact than warming, at least on plant communities dependent on long snow cover. Consequently, they are the most vulnerable to climate change and their persistence in the near future is seriously threatened. Subalpine and alpine grasslands are more stable and, until now, they do not seem to be affected by a warmer climate

Surgery and the spinorial tau-invariant

We associate to a compact spin manifold M a real-valued invariant \tau(M) by taking the supremum over all conformal classes over the infimum inside each conformal class of the first positive Dirac eigenvalue, normalized to volume 1. This invariant is a spinorial analogue of Schoen's $\sigma$-constant, also known as the smooth Yamabe number. We prove that if N is obtained from M by surgery of codimension at least 2, then $\tau(N) \geq \min\{\tau(M),\Lambda_n\}$ with $\Lambda_n>0$. Various topological conclusions can be drawn, in particular that \tau is a spin-bordism invariant below $\Lambda_n$. Below $\Lambda_n$, the values of $\tau$ cannot accumulate from above when varied over all manifolds of a fixed dimension.Comment: to appear in CPD

Zinc increases the effects of essential amino acids-whey protein supplements in frail elderly

Abstract: Protein undernutrition is frequent in the elderly. It contributes to the development of osteoporosis, possibly via lower IGF-I. Dietary zinc can influence IGF-I production. Objectives: To determine the influence of dietary zinc addition on IGF-I and bone turnover responses to essential amino acids-whey (EAA-W) protein supplements in frail elderly. Design and setting: A daily oral protein supplement was given to hospitalized patients for 4 weeks. On a randomized, double-blind basis, patients received either an additional 30 mg/day of zinc or control. Participants: Sixty-one hospitalized elderly aged 66.7 to 105.8, with a mini-nutritional assessment score between 17 and 24 were enrolled. Measurements: Activities of daily living; dietary intakes; serum IGF-I, IGF-BP3, CrossLaps™, osteocalcin and zinc were measured before and after 1, 2 and 4 weeks of protein supplementation. Results: Serum IGF-I rapidly increased in both groups. Zinc accelerated this increase with changes of +48.2±14.3 and +22.4±4.7% (p<.05) by 1 week, in the zinc-supplemented and control groups, respectively. Zinc significantly decreased the serum bone resorption marker CrossLaps™ by already 1 week. Activities of daily living improved by +27.0±3.1 and +18.3±4.5% in zinc-supplemented and control groups, respectively. Conclusion: In the elderly, zinc supplementation accelerated the serum IGF-I response to EAA-W protein by 1 week and decreased a biochemical marker of bone resorptio