2,176 research outputs found
Programming Idioms for Transactional Events
Transactional events (TE) are an extension of Concurrent ML (CML), a
programming model for synchronous message-passing. Prior work has focused on
TE's formal semantics and its implementation. This paper considers programming
idioms, particularly those that vary unexpectedly from the corresponding CML
idioms. First, we solve a subtle problem with client-server protocols in TE.
Second, we argue that CML's wrap and guard primitives do not translate well to
TE, and we suggest useful workarounds. Finally, we discuss how to rewrite CML
protocols that use abort actions
The Maternal Effect: Carrying the Consequences of Nutrition Across Generations
Let’s indulge ourselves in a deer-management fantasy for a moment. I’m sure it won’t be your first time! Imagine you are blessed to own and manage your own block of deer country for several years (for many fortunate readers, this is reality, not fantasy). Although the ground you purchase holds plenty of deer, the overgrown forests and grassy meadows might not be providing the nutrition necessary for these deer to achieve their genetic potential. In addition, the 6-foot high browse line resulting from extreme overabundance of deer is a likely indication of why only scrawny looking bucks are typically harvested in the area. However, you know what it takes to have healthy deer herd and grow bigger bucks, and you can see the potential your property holds. Like any responsible steward of the land, you do your homework and go the extra mile to increase the diversity of the habitat and offer more forage and browse. You establish proper food plots with forage high in digestibility and protein. You harvest numerous does each year to reduce deer numbers to a sustainable level, and conservatively harvest bucks to balance the sex ratio and develop an age structure that includes bucks of many ages. During this time, you also foster a small data-collection program framed around the close monitoring of the harvest each year, and in particular the size and age of the bucks being harvested. After a few years of intensive management, hard work, and patience, the property appears to be in better shape; a browse line is no longer evident, deer numbers are in check, bucks and does that are harvested exhibit greater fat levels, and the buck harvest is comprised mainly of mature bucks over 4½ years of age
Effects of Deer Settling Stimulus and Deer Density on Regeneration in a Harvested Southern New England Forest
Elevated deer densities have led to reports of forest regeneration failure and ecological damage. However, there is growing evidence that the biophysical conditions of a forest that make it attractive to deer may be a contributing factor in determining browsing levels. Thus, an understanding of settling stimulus—how attractive an area is to deer in terms of food-independent habitat requirements—is potentially important to manage deer browsing impacts. We tested the settling stimulus hypothesis by evaluating the degree to which thermal settling stimulus and deer density are related to spatial variation in browsing intensity across different forest harvesting strategies over the course of a year. We determined if deer were impacting plant communities and if they resulted in changes in plant cover. We quantified the thermal environment around each harvest and tested to see if it influenced deer density and browsing impact. We found that deer had an impact on the landscape but did not alter plant cover or diminish forest regeneration capacity. Deer density and browse impact had a relationship with thermal settling stimulus for summer and fall months, and deer density had a relationship with browse impact in the winter on woody plants. We conclude that thermal settling stimulus is an important predictor for deer density and browsing impact
Comparison and Correlation of Dynamic Postural Stability Indices Obtained during Different Dynamic Landing Tasks and Footwear Conditions
Objectives: To compare the dynamic postural stability indices (DPSI) from two different landing protocols with normalized jump distance (NDP) and jump height (RWDP) and footwear conditions (barefoot and shod).Design: Cross-sectional.Setting: Research laboratory.Participants: Twenty-five physically active adults (13 males/12 females, age: 22.1±4.2yrs, height: 178.3±11.1cm, weight: 75.6±19.4kg).Main Outcome Measures: Subjects jumped off two feet and landed with their preferred foot on a force-plate. From the ground reaction forces, the DPSI scores in the anterior-posterior, medial-lateral, and vertical directions, and the cumulative scores (DPSI) were calculated under two protocols and footwear conditions. Based on normality of data distribution, paired t-tests/Wilcoxon signed rank tests and Pearson/Spearman correlation coefficients were used to compare, and measure the relationship between the two protocols under two footwear conditions (p<0.05).Results: There were mixed results for DPSI scores when comparing the two protocols. There were significant differences (p=0.001–0.039) and positive correlations (r=0.660–0.870, p<0.001) on the DPSI scores between footwear conditions during the NDP protocol while the RWDP showed no significant differences.Conclusions: Different protocols and footwear conditions may impact DPSI scores. Therefore, a standardized protocol and footwear condition should be established for future studies examining dynamic postural stability
Preserving cultural heritage: Analyzing the antifungal potential of ionic liquids tested in paper restoration
Early industrialization and the development of cheap production processes for paper have led to an exponential accumulation of paper-based documents during the last two centuries. Archives and libraries harbor vast amounts of ancient and modern documents and have to undertake extensive endeavors to protect them from abiotic and biotic deterioration. While services for mechanical preservation such as ex post de-acidification of historic documents are already commercially available, the possibilities for long-term protection of paper-based documents against fungal attack (apart from temperature and humidity control) are very limited. Novel processes for mechanical enhancement of damaged cellulosic documents use Ionic Liquids (IL) as essential process components. With some of these ILs having azolefunctionalities similar to well-known fungicides such as Clotrimazole, the possibility of antifungal activities of these ILs was proposed but has not yet been experimentally confirmed. We evaluated the potency of four ILs with potential application in paper restoration for suppression of fungal growth on five relevant paper-infesting molds. The results revealed a general antifungal activity of all ILs, which increased with the size of the non-polar group. Physiological experiments and ultimate elemental analysis allowed to determine the minimal inhibitory concentration of each IL as well as the residual IL concentration in process-treated paper. These results provide valuable guidelines for IL-applications in paper restoration processes with antifungal activity as an added benefit. With azoles remaining in the paper after the process, simultaneous repair and biotic protection in treated documents could be facilitated
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Unusual sources of fossil micrometeorites deduced from relict chromite in the small size fraction in ~467 Ma old limestone
Extraterrestrial chrome spinel and chromite extracted from the sedimentary rock record are relicts from coarse micrometeorites and rarely meteorites. They are studied to reconstruct the paleoflux of meteorites to the Earth and the collisional history of the asteroid belt. Minor element concentrations of Ti and V, and oxygen isotopic compositions of these relict minerals were used to classify the meteorite type they stem from, and thus to determine the relative meteorite group abundances through time. While coarse sediment-dispersed extraterrestrial chrome-spinel (SEC) grains from ordinary chondrites dominate through the studied time windows in the Phanerozoic, there are exceptions: We have shown that ~467 Ma ago, 1 Ma before the breakup of the L chondrite parent body (LCPB), more than half of the largest (>63 μm diameter) grains were achondritic and originated from differentiated asteroids in contrast to ordinary chondrites which dominated the meteorite flux throughout most of the past 500 Ma. Here, we present a new data set of oxygen isotopic compositions and elemental compositions of 136 grains of a smaller size fraction (32–63 μm) in ~467 Ma old pre-LCPB limestone from the Lynna River section in western Russia, that was previously studied by elemental analysis. Our study constitutes the most comprehensive oxygen isotopic data set of sediment-dispersed extraterrestrial chrome spinel to date. We also introduce a Raman spectroscopy-based method to identify SEC grains and distinguish them from terrestrial chrome spinel with ~97% reliability. We calibrated the Raman method with the established approach using titanium and vanadium concentrations and oxygen isotopic compositions. We find that ordinary chondrites are approximately three times more abundant in the 32–63 μm fraction than achondrites. While abundances of achondrites compared to ordinary chondrites are lower in the 32–63 μm size fraction than in the >63 μm one, achondrites are approximately three times more abundant in the 32–62 μm fraction than they are in the present flux. We find that the sources of SEC grains vary for different grain sizes, mainly as a result of parent body thermal metamorphism. We conclude that the meteorite flux composition ~467 Ma ago ~1 Ma before the breakup of the LCPB was fundamentally different from today and from other time windows studied in the Phanerozoic, but that in contrast to the large size fraction ordinary chondrites dominated the flux in the small size fraction. The high abundance of ordinary chondrites in the studied samples is consistent with the findings based on coarse extraterrestrial chrome-spinel from other time windows
DNA cytosine hydroxymethylation levels are distinct among non-overlapping classes of peripheral blood leukocytes
AbstractBackgroundPeripheral blood leukocytes are the most commonly used surrogates to study epigenome-induced risk and epigenomic response to disease-related stress. We considered the hypothesis that the various classes of peripheral leukocytes differentially regulate the synthesis of 5-methylcytosine (5mCG) and its removal via Ten-Eleven Translocation (TET) dioxygenase catalyzed hydroxymethylation to 5-hydroxymethylcytosine (5hmCG), reflecting their responsiveness to environment. Although it is known that reductions in TET1 and/or TET2 activity lead to the over-proliferation of various leukocyte precursors in bone marrow and in development of chronic myelomonocytic leukemia and myeloproliferative neoplasms, the role of 5mCG hydroxymethylation in peripheral blood is less well studied.ResultsWe developed simplified protocols to rapidly and reiteratively isolate non-overlapping leukocyte populations from a single small sample of fresh or frozen whole blood. Among peripheral leukocyte types we found extreme variation in the levels of transcripts encoding proteins involved in cytosine methylation (DNMT1, 3A, 3B), the turnover of 5mC by demethylation (TET1, 2, 3), and DNA repair (GADD45A, B, G) and in the global and gene-region-specific levels of DNA 5hmCG (CD4+ T cells≫CD14+ monocytes>CD16+ neutrophils>CD19+ B cells>CD56+ NK cells>Siglec8+ eosinophils>CD8+ T cells).ConclusionsOur data taken together suggest a potential hierarchy of responsiveness among classes of leukocytes with CD4+, CD8+ T cells and CD14+ monocytes being the most distinctly poised for a rapid methylome response to physiological stress and disease
Agenda for Translating Physical Activity, Nutrition, and Weight Management Interventions for Cancer Survivors into Clinical and Community Practice.
Evidence supporting physical activity, diet, and weight management for cancer survivors has grown, leading to the development of guidelines and interventions. The next step is to identify necessary practice and policy changes and to develop a research agenda to inform how interventions can be delivered to survivors most effectively and efficiently in health care settings and by community-based organizations. Here, an agenda is proposed for research, practice, and policy that incorporates recommendations for a range of programming options, a patient-centered, tailored screening and referral approach, and training needs for survivorship care providers and providers of exercise, nutrition, and weight management services. Research needs to focus on sustainability, dissemination, and implementation. Needed policy changes are presented, as well as opportunities to leverage current health care policies
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