2,076 research outputs found

    The scheduling techniques of ESP2

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    The Mission Analysis Division of the Systems Analysis and Integration Laboratory at the Marshall Space Flight Center has developed a robust automatic scheduler which can produce detailed schedules for the multi-step activities required for payload operations on the Space Station. This scheduler, a part of the Expert Scheduling Program (ESP2), has five components: the bookkeeper, checker, loader, selector, and explainer. The bookkeeper maintains the usage profiles for nondepletable resources, consumables, equipment, crew, and the times of all the steps for the payload activities for several different schedules simultaneously. The checker searches the data maintained by the bookkeeper and finds times when the constraints of each step of an activity are satisfied. The loader is an expert system that uses the techniques of forward chaining, depth-first searching, and backtracking to manage the workings of the checker so that activities are placed in the schedule without violating constraints (such as crew, resources, and orbit opportunities). The checker searches the data maintained by the bookkeeper and finds times when the constraints of each step of an activity are satisfied. The loader is an expert system which uses the techniques of forward chaining, depth-first searching, and backtracking to manage the workings of the checker so that activities are placed in the schedule without violating the constraints. The selector has several methods of choosing the next activity for the loader to schedule. The explainer shows the user why an activity was or was not scheduled at a certain time; it offers a unique graphical explanation of how the expert system (the loader) works

    Conflict in the Workplace: An Empirical Analysis of the Antecedents and Resolutions

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    Various types of conflict can be identified in organizations, such as interpersonal conflict, team conflict, and inter-group conflict. Conflict resolution is crucial in the workplace to create a healthy and happy work environment employees want to work in. Without effective conflict resolution, it would be hard for people to get along, quality work wouldn’t get done, and it would be difficult to communicate effectively between employees, teams, and departments. This report will focus on the different underlying causes of conflict at the individual level in the workplace and what strategies are used to solve these conflicts. The information collected for the report has been conducted through two surveys with employees from Fastenal. This study offers ways to find the best strategies to overcome interpersonal conflict in the workplace.https://openriver.winona.edu/urc2019/1095/thumbnail.jp

    Wnts acting through canonical and noncanonical signaling pathways exert opposite effects on hippocampal synapse formation

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    <p>Abstract</p> <p>Background</p> <p>Wnt proteins comprise a large class of signaling molecules that regulate a variety of developmental processes, including synapse formation. Previous studies have shown Wnts to be involved in both the induction and prevention of synapses in a number of different organisms. However, it is not clear whether the influence of Wnts on synapses is a result of Wnts' behavior in different organisms or differences in the activity of different Wnt ligands.</p> <p>Results</p> <p>We used <it>in situ </it>hybridization to show that several Wnt ligands (Wnt3, Wnt5a, Wnt7a, and Wnt7b) and their receptors, Frizzled, are expressed in the developing hippocampus during the period of synapse formation in rodents. We used recombinant Wnt protein or Wnt conditioned media to explore the effects of Wnts on synapses in hippocampal cultures. We found that Wnt7a and Wnt7b activate canonical signaling, whereas Wnt5a activates a noncanonical pathway. The activation of the canonical pathway, either through pathway manipulations or through Wnt stimulation, increases presynaptic inputs. In contrast, exposure to Wnt5a, which activates a noncanonical signaling pathway, decreases the number of presynaptic terminals.</p> <p>Conclusion</p> <p>Our observations suggest that the pro- and antisynaptogenic effects of Wnt proteins are associated with the activation of the canonical and noncanonical Wnt signaling pathways.</p

    A format for the interchange of scheduling models

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    In recent years a variety of space-activity schedulers have been developed within the aerospace community. Space-activity schedulers are characterized by their need to handle large numbers of activities which are time-window constrained and make high demands on many scarce resources, but are minimally constrained by predecessor/successor requirements or critical paths. Two needs to exchange data between these schedulers have materialized. First, there is significant interest in comparing and evaluating the different scheduling engines to ensure that the best technology is applied to each scheduling endeavor. Second, there is a developing requirement to divide a single scheduling task among different sites, each using a different scheduler. In fact, the scheduling task for International Space Station Alpha (ISSA) will be distributed among NASA centers and among the international partners. The format used to interchange scheduling data for ISSA will likely use a growth version of the format discussed in this paper. The model interchange format (or MIF, pronounced as one syllable) discussed in this paper is a robust solution to the need to interchange scheduling requirements for space activities. It is highly extensible, human-readable, and can be generated or edited with common text editors. It also serves well the need to support a 'benchmark' data case which can be delivered on any computer platform

    Bayesian Geostatistical Analysis and Ecoclimatic Determinants of Corynebacterium pseudotuberculosis Infection among Horses

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    Citation: Boysen, C., Davis, E. G., Beard, L. A., Lubbers, B. V., & Raghavan, R. K. (2015). Bayesian Geostatistical Analysis and Ecoclimatic Determinants of Corynebacterium pseudotuberculosis Infection among Horses. Plos One, 10(10), 15. doi:10.1371/journal.pone.0140666Kansas witnessed an unprecedented outbreak in Corynebacterium pseudotuberculosis infection among horses, a disease commonly referred to as pigeon fever during fall 2012. Bayesian geostatistical models were developed to identify key environmental and climatic risk factors associated with C. pseudotuberculosis infection in horses. Positive infection status among horses (cases) was determined by positive test results for characteristic abscess formation, positive bacterial culture on purulent material obtained from a lanced abscess (n = 82), or positive serologic evidence of exposure to organism (>= 1:512)(n = 11). Horses negative for these tests (n = 172)(controls) were considered free of infection. Information pertaining to horse demographics and stabled location were obtained through review of medical records and/or contact with horse owners via telephone. Covariate information for environmental and climatic determinants were obtained from USDA (soil attributes), USGS (land use/land cover), and NASA MODIS and NASA Prediction of Worldwide Renewable Resources (climate). Candidate covariates were screened using univariate regression models followed by Bayesian geostatistical models with and without covariates. The best performing model indicated a protective effect for higher soil moisture content (OR = 0.53, 95% CrI = 0.25, 0.71), and detrimental effects for higher land surface temperature (>= 35 degrees C) (OR = 2.81, 95% CrI = 2.21, 3.85) and habitat fragmentation (OR = 1.31, 95% CrI = 1.27, 2.22) for C. pseudotuberculosis infection status in horses, while age, gender and breed had no effect. Preventative and ecoclimatic significance of these findings are discussed

    Effects of grain by-products as supplements for stocker cattle grazing bermudagrass

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    Two experiments were conducted to compare corn, dried distillers’ grains (DDG), and pelleted soybean hulls (SH) as supplements for cattle grazing bermudagrass. In Exp. 1, 66 crossbred steers (306 ± 3.2 kg) were stratified by weight and allotted randomly to six 2.4-ha bermudagrass pastures for a 107-d study. One of three supplement treatments (corn, DDG, or SH) was assigned randomly to each pasture group and was offered at 0.5% (as fed) of body weight. Calves were weighed at 28-d intervals and supplement was adjusted after each weigh period. In Exp. 2, five ruminally cannulated steers grazed bermudagrass pasture and were individually fed supplements (corn, DDG, or SH) at 0.5% of body weight in a 3 x 3 replicated, incomplete Latin-square design with a 14-d adaptation and a 5-d sampling period. In Exp. 1, supplementation with DDG and corn increased (P \u3c 0.04) the average daily gain compared to supplementation with SH (0.89, 0.87, and 0.74 kg for DDG, corn, and SH, respectively). In Exp. 2, in situ dry-matter-disappearance kinetic measures of bermudagrass were not affected by type of supplementation. The potential extent of digestion for DDG (93%) was lower than for corn (97%, P = 0.01) and SH (96%, P = 0.06). Supplementation with corn or DDG at 0.5% of body weight improved the gain of stocker cattle grazing bermudagrass compared to supplementation with SH, but these differences were not explained by differences in bermudagrass degradation kinetic

    U.S. Women's Intended Sources for Reproductive Health Care

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    Introduction: The current sociopolitical climate and context of the Affordable Care Act have led some to question the future role of family planning clinics in reproductive health care. We explored where women plan to get their future contraception, pelvic exam/pap smears, and sexually transmitted infection testing, with a focus on the role of family planning clinics. Methods: Data were drawn from a study of United States adults conducted in January 2013 from a national online panel. We focused on English-literate women aged 18?45 years who answered items on intended sources of care (private office/health maintenance organization [HMO], family planning clinic, other, would not get care) for reproductive health services. We used Rao-Scott F tests to compare intended sources across sociodemographic groups, and logistic regression to model odds of intending to use family planning clinics. Probability weights were used to adjust for the complex sampling design. Results: The response rate was 61% (n?=?2,182). Of the 723 respondents who met the inclusion criteria, approximately half intended to use private offices/HMOs. Among some subgroups, including less educated (less than high school), lower annual incomes (<$25,000) and uninsured women, the proportion intending to use family planning clinics was higher than the proportion intending to use private office/HMO in unadjusted analyses. Across all service types, unmarried and uninsured status were associated with intention to use family planning clinics in multivariable models. Conclusions: While many women intend to use private offices/HMOs for their reproductive health care, family planning clinics continue to play an important role, particularly for socially disadvantaged women.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140133/1/jwh.2014.5116.pd

    Chimpanzees demonstrate individual differences in social information use

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    Studies of transmission biases in social learning have greatly informed our understanding of how behaviour patterns may diffuse through animal populations, yet within-species inter-individual variation in social information use has received little attention and remains poorly understood. We have addressed this question by examining individual performances across multiple experiments with the same population of primates. We compiled a dataset spanning 16 social learning studies (26 experimental conditions) carried out at the same study site over a 12-year period, incorporating a total of 167 chimpanzees. We applied a binary scoring system to code each participant’s performance in each study according to whether they demonstrated evidence of using social information from conspecifics to solve the experimental task or not (Social Information Score—‘SIS’). Bayesian binomial mixed effects models were then used to estimate the extent to which individual differences influenced SIS, together with any effects of sex, rearing history, age, prior involvement in research and task type on SIS. An estimate of repeatability found that approximately half of the variance in SIS was accounted for by individual identity, indicating that individual differences play a critical role in the social learning behaviour of chimpanzees. According to the model that best fit the data, females were, depending on their rearing history, 15–24% more likely to use social information to solve experimental tasks than males. However, there was no strong evidence of an effect of age or research experience, and pedigree records indicated that SIS was not a strongly heritable trait. Our study offers a novel, transferable method for the study of individual differences in social learning

    Forearc Peridotites from Tonga Record Heterogeneous Oxidation of the Mantle following Subduction Initiation

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    The elevated oxygen fugacity recorded by subduction-related lavas and peridotites, relative to their mid-ocean ridge counterparts, fundamentally influences the petrogenesis of arc magmas. However, the timing, process, and spatial extent of oxidizing mass transfer at subduction zones remain unknown. Forearc peridotites, which are sometimes exposed on the trench wall of the overriding plate, record chemical fingerprints of the melting and melt–rock interaction processes that occur during and following subduction initiation, and thus provide insight into the spatial and temporal evolution of this oxidized signature. In this study, we present new major element, trace element, and oxygen fugacity data for a suite of forearc peridotites recovered from the Tonga Trench, in addition to a new assessment of literature data for previously studied forearc peridotites. For Tonga samples and literature data for forearc, ridge, and subduction-zone peridotites, we calculate oxygen fugacity (fO2) using an updated method. In contrast to previous studies, we find that spinel Cr#, a proxy for extent of melt extraction, does not correlate with oxygen fugacity, such that many forearc peridotites with high spinel Cr# do not record oxygen fugacity higher than the mid-ocean ridge peridotite array. Combining these observations with trace element modeling, we conclude that forearc peridotites are less pervasively influenced by oxidation owing to subduction processes than previously reported. The oxygen fugacity recorded by Tonga forearc peridotites is heterogeneous between dredges and homogeneous within dredges. To explore these variations, we grouped the dredges into two categories. Group I peridotites have high spinel Cr#, extremely depleted trace element compositions and oxygen fugacity values consistent with the mid-ocean ridge peridotite array. We interpret these to be the residues of large degrees of fractional melting, with little influence from arc-like melts or fluids, formed during the first stages of subduction initiation. Group II peridotites have lower spinel Cr#, enriched light rare earth elements, and oxygen fugacity elevated by ≥1 log unit above the mid-ocean peridotite array. We interpret these peridotites to be the residues of flux melting, initiated once corner flow is established in the young subduction zone. We conclude that the forearc mantle is not pervasively oxidized relative to mid-ocean ridge mantle, and that the asthenospheric mantle in the proto-subduction zone region is not oxidized prior to subduction initiation. As the oxidized signature in Group II peridotites accompanies geochemical evidence of interaction with subduction-related fluids and melts, this suggests that the sub-arc mantle is oxidized concurrently with addition of subduction fluids to the mantle wedge
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