2,608 research outputs found
Can Conservation and Profits Co-Exist?: The Case of Lion Hunting
Resource /Energy Economics and Policy,
Investigation of Part Accuracy and Surface Roughness in Rapid Freeze Prototyping Based Investment Casting
The study as described in this paper is aimed at investigating the dimensional accuracy
and surface finish of metal parts made by investment casting with ice patterns generated by rapid
freeze prototyping. The process of investment casting with ice patterns is described and contrast
with conventional investment casting with wax patterns is made. The selection of binder material
for ceramic slurries and the need for an interface agent to separate the ice pattern from the
ceramic slurry in the mold making process are discussed. The accuracy and surface finish of ice
patterns and of the metal castings are presented and discussed. The parts used in this
investigation include cylinders with vertical and slant walls and a turbine impeller.The authors gratefully acknowledge the financial support from the National Science
Foundation grants (DMI-0128313 and DMI-0140625) and the Research Board of University of
Missouri at Rolla.Mechanical Engineerin
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Large-effect flowering time mutations reveal conditionally adaptive paths through fitness landscapes in Arabidopsis thaliana.
Contrary to previous assumptions that most mutations are deleterious, there is increasing evidence for persistence of large-effect mutations in natural populations. A possible explanation for these observations is that mutant phenotypes and fitness may depend upon the specific environmental conditions to which a mutant is exposed. Here, we tested this hypothesis by growing large-effect flowering time mutants of Arabidopsis thaliana in multiple field sites and seasons to quantify their fitness effects in realistic natural conditions. By constructing environment-specific fitness landscapes based on flowering time and branching architecture, we observed that a subset of mutations increased fitness, but only in specific environments. These mutations increased fitness via different paths: through shifting flowering time, branching, or both. Branching was under stronger selection, but flowering time was more genetically variable, pointing to the importance of indirect selection on mutations through their pleiotropic effects on multiple phenotypes. Finally, mutations in hub genes with greater connectedness in their regulatory networks had greater effects on both phenotypes and fitness. Together, these findings indicate that large-effect mutations may persist in populations because they influence traits that are adaptive only under specific environmental conditions. Understanding their evolutionary dynamics therefore requires measuring their effects in multiple natural environments
Factors Affecting Pregnancy in Free-ranging Elk, Cervus elaphus nelsoni, in Michigan
Uncertainty exists as to which factors are most closely related to probability of pregnancy in Elk (Cervus elaphus), which thresholds are key for managers who want to assess the potential productivity of free-ranging Elk herds, and whether these thresholds vary among populations. We examined relationships among pregnancy, age, and mass for 513 harvested free-ranging Elk in Michigan, and compared relationships with other published models and with thresholds derived from other free-ranging and penned populations to see if relationships were consistent among populations. Pregnancy rates varied (chi22 = 136.3; P < 0.0001) among yearling (0.30), prime-aged (2.5-11.5-year-olds; 0.88), and old (> 12.5-year-olds; 0.60) cows. Probability of pregnancy in adult cows was related to mass (chi2 = 7.4; P = 0.006), age (chi2 = 12.6; P = 0.0004) and age class (chi2 = 16.4; P < 0.0001), but not to lactation status (chi2 = 0.4; P = 0.515); pregnancy was also positively related (chi2 = 15.8; P < 0.0001) to mass in yearlings. Probability of pregnancy increased 1.02× and 1.04× for each 1 kg increase in body mass of adult and yearling cows, respectively, and prime-aged cows were 4.9× more likely to conceive than old cows. Compared to thresholds derived primarily from penned or farmed Elk, both adult and yearling free-ranging Elk in Michigan and elsewhere were able to achieve higher levels of pregnancy at lower body mass. Thresholds also varied among free-ranging Elk populations. Given variation among populations, managers should calibrate mass-pregnancy relationships for their respective populations to determine whether condition is potentially limiting pregnancy in their populations
Management of bovine tuberculosis in Michigan wildlife: Current status and near term prospects
Surveillance and control activities for bovine tuberculosis (bTB) in free-ranging Michigan white-tailed deer (Odocoileus virginianus) have now been underway for over a decade. Significant progress has been made, lowering apparent prevalence in deer in the core area by >60%, primarily via reduction of deer densities through hunting, and restrictions on public feeding and baiting of deer. These broad strategies of the Michigan Department of Natural Resources (MDNR), implemented with the cooperation of Michigan deer hunters, halved the deer population in the bTB endemic area. However, as hunters see fewer deer, their willingness to sustain aggressive harvests has waned, and public resentment of control measures has grown.
During the past four years, apparent prevalence in core area deer has held approximately steady just below 2%. After bottoming out in 2004 at an estimated 10–12 deer/km2, deer numbers have since rebounded by ∼30%. Public compliance with baiting and feeding restrictions has been variable. In general, hunters in the core area do not perceive bTB as a problem, in spite of 13 years of MDNR outreach. To date, MDNR has expended more than US63 million spent to date devoted to whole herd testing.
Nevertheless, some initiatives justify cautious optimism. Promising research to support eventual vaccination of wild deer continues. Some hunters and landowners have begun to recognize the costs of high deer densities and supplemental feeding. A peninsula-wide ban on baiting and feeding was enacted. Some cattle producers, recognizing their precarious circumstances, have begun work to change long-held prevailing opinions among their peers about farm biosecurity. Yet formidable challenges remain, and evidence suggests that eradication of bTB, if it can be achieved, will take decades, and will require greater public and political resolve than has been demonstrated thus far
Adaptation strategies and approaches for forested watersheds
Intentional climate adaptation planning for ecosystems has become a necessary part of the job for natural resource managers and natural resource professionals in this era of non-stationarity. One of the major challenges in adapting ecosystems to climate change is in the translation of broad adaptation concepts to specific, tangible actions. Addressing management goals and values while considering the long-term risks associated with local climate change can make forested watershed management plans more robust to uncertainty and changing conditions. We provide a menu of tiered adaptation strategies, which we developed with a focus on forests of the Midwest and Northeastern U.S., as part of a flexible framework to support the integration of climate change considerations into forested watershed management and conservation activities. This menu encapsulates ideas from the literature into statements that signify climate adaptation intention and provide examples of associated tactics to help ground the concepts in specific actions. Finally, we describe two demonstration projects, shared through the Northern Institute of Applied Climate Science’s Climate Change Response Framework, that have used this Forested Watershed Adaptation Menu and Adaptation Workbook in project-level planning
\u3ci\u3eMycobacterium bovis \u3c/i\u3ein Coyotes from Michigan
During a survey for tuberculosis in wild carnivores and omnivores, Mycobacteriurn bovis was cultured from pooled lymph nodes of three adult female coyotes (Canis latrans) harvested by hunters in Michigan (USA). No gross or histologic lesions suggestive of tuberculosis were seen in these animals. One coyote was taken from Montmorency county and two coyotes from Alcona county located in the northeastern portion of Michigan’s Lower Peninsula where free-ranging white-tailed deer (Odocoileus virginianus) have been found infected with bovine tuberculosis. It is thought that these coyotes became infected with M. bovis through the consumption of tuberculous deer. Other species included in the survey were the opossum (Didelphis virginiana), raccoon (Procyon lotor), red fox (Vulpes vulpes), bobcat (Felis rufus), and badger (Taxidea taxus)
Salinity and temperature balances at the SPURS central mooring during fall and winter
Author Posting. © The Oceanography Society, 2015. This article is posted here by permission of The Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 28, no. 1 (2015): 56-65, doi:10.5670/oceanog.2015.06.One part of the Salinity Processes in the Upper-ocean Regional Study (SPURS) field campaign focused on understanding the physical processes affecting the evolution of upper-ocean salinity in the region of climatological maximum sea surface salinity in the subtropical North Atlantic (SPURS-1). An upper-ocean salinity budget provides a useful framework for increasing this understanding. The SPURS-1 program included a central heavily instrumented mooring for making accurate measurements of air-sea surface fluxes, as well as other moorings, Argo floats, and gliders that together formed a dense observational array. Data from this array are used to estimate terms in the upper-ocean salinity and heat budgets during the SPURS-1 campaign, with a focus on the first several months (October 2012 to February 2013) when the surface mixed layer was becoming deeper, fresher, and cooler. Specifically, we examine the salinity and temperature balances for an upper-ocean mixed layer, defined as the layer where the density is within 0.4 kg m–3 of its surface value. The gross features of the evolution of upper-ocean salinity and temperature during this fall/winter season are explained by a combination of evaporation and precipitation at the sea surface, horizontal transport of heat and salt by mixed-layer currents, and vertical entrainment of fresher, cooler fluid into the layer as it deepened. While all of these processes were important in the observed seasonal (fall) freshening at this location in the salinity-maximum region, the variability of salinity on monthly-to-intraseasonal time scales resulted primarily from horizontal advection.J.T. Farrar,
A.J. Plueddemann, J.B. Edson, and the deployment of
the central mooring were supported by NASA grant
NNX11AE84G. L. Rainville, C. Lee, C. Eriksen, and the
Seaglider program were supported by NASA grant
NNX11AE78G. R. Schmitt was supported by NSF grant
OCE-1129646. B. Hodges and D. Fratantoni were supported
by NASA grant NNX11AE82G. The Prawler
moorings were funded by PMEL. The data analysis
was also supported by NASA grant NNX14AH38G
Super-conservative interpretation of muon g-2 results applied to supersymmetry
The recent developments in theory and experiment related to the anomalous
magnetic moment of the muon are applied to supersymmetry. We follow a very
cautious course, demanding that the supersymmetric contributions fit within
five standard deviations of the difference between experiment and the standard
model prediction. Arbitrarily small supersymmetric contributions are then
allowed, so no upper bounds on superpartner masses result. Nevertheless,
non-trivial exclusions are found. We characterize the substantial region of
parameter space ruled out by this analysis that has not been probed by any
previous experiment. We also discuss some implications of the results for
forthcoming collider experiments.Comment: 10 pages, latex, 3 fig
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