284 research outputs found

    Finite-dimensional hopf algebras are free over grouplike subalgebras

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    AbstractLet H be a finite-dimensional Hopf algebra over a field k, and let G be a subgroup of the group of grouplikes of H. Then every left (H,kG)-Hopf module is free as a left kG-module. If k is algebraically closed and C is a simple subcoalgebra of H with gC = C for all g ∈ G, then the exponent of G and (in characteristic p > 0) the p-part of |G| divide n, wheren2 is the dimension of C

    The Grothendieck group of a Hopf algebra

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    AbstractLet H be a cosemisimple Hopf algebra over an algebraically closed field k. We show that if H contains a simple subcoalgebra of dimension 4, then H contains either a Hopf subalgebra of dimension 2, 12, or 60, or a simple subcoalgebra of dimension n2 for each positive integer n. In particular, if H is finite dimensional, then it has even dimension

    Conceptual design study: Forest Fire Advanced System Technology (FFAST)

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    An integrated forest fire detection and mapping system that will be based upon technology available in the 1990s was defined. Uncertainties in emerging and advanced technologies related to the conceptual design were identified and recommended for inclusion as preferred system components. System component technologies identified for an end-to-end system include thermal infrared, linear array detectors, automatic georeferencing and signal processing, geosynchronous satellite communication links, and advanced data integration and display. Potential system configuration options were developed and examined for possible inclusion in the preferred system configuration. The preferred system configuration will provide increased performance and be cost effective over the system currently in use. Forest fire management user requirements and the system component emerging technologies were the basis for the system configuration design. A preferred system configuration was defined that warrants continued refinement and development, examined economic aspects of the current and preferred system, and provided preliminary cost estimates for follow-on system prototype development

    Genetic Introgression and the Survival of Florida Panther Kittens

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    Estimates of survival for the young of a species are critical for population models. These models can often be improved by determining the effects of management actions and population abundance on this demographic parameter. We used multiple sources of data collected during 1982–2008 and a live-recapture dead-recovery modeling framework to estimate and model survival of Florida panther (Puma concolor coryi) kittens (age 0–1 year). Overall, annual survival of Florida panther kittens was 0.323 ± 0.071 (SE), which was lower than estimates used in previous population models. In 1995, female pumas from Texas (P. c. stanleyana) were released into occupied panther range as part of an intentional introgression program to restore genetic variability. We found that kitten survival generally increased with degree of admixture: F1 admixed and backcrossed to Texas kittens survived better than canonical Florida panther and backcrossed to canonical kittens. Average heterozygosity positively influenced kitten and older panther survival, whereas index of panther abundance negatively influenced kitten survival. Our results provide strong evidence for the positive population-level impact of genetic introgression on Florida panthers. Our approach to integrate data from multiple sources was effective at improving robustness as well as precision of estimates of Florida panther kitten survival, and can be useful in estimating vital rates for other elusive species with sparse data

    Providing the Nation a Significant "High-Test Peroxide" Propulsion Test Capability

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    Renewed interest in high-test peroxide, as a propellant, required the development of a facility capable of testing rocket propulsion systems. The development of this capability at the NASA Stennis Space Center (SSC), MS, focused on meeting this requirement. The challenges, accomplishments, and lessons learned associated with developing the SSC E3 Test Facility's high-test peroxide capability are presented herein

    Proper nutrition can prevent negative health outcomes in young female athletes

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    Since the onset of Title IX, opportunities have dramatically increased for female athletes, largely to their benefit. However, some negative health outcomes such as disordered eating, chronic menstrual disturbances and low bone mass have been associated with high-level competition among some female athletes, particularly in sports such as gymnastics and cross-country running, where a slender physique or lean body build is important. Adolescent female athletes, in a rapid growth and development phase, may be at greatest risk. We sought to identify athletes at risk, understand the origin of possible negative outcomes and recommend behavioral modifications that promote participation in competitive sports while supporting lifetime health. This review discusses the development and impact of disordered eating and menstrual dysfunction on bone mass in young, competitive, female athletes and provides nutrition recommendations for their energy, carbohydrate, protein, vitamin and mineral intake

    Trees and shrubs as sources of fodder in Australia

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    Experience with browse plants in Australia is briefly reviewed in terms of their forage value to animals, their economic value to the landholder and their ecological contribution to landscape stability. Of the cultivated species only two have achieved any degree of commercial acceptance (Leucaena leucocephala and Chamaecytisus palmensis). Both of these are of sufficiently high forage value to be used as the sole source of feed during seasonal periods of nutritional shortage. Both are also leguminous shrubs that establish readily from seed. It is suggested that a limitation in their present use is the reliance on stands of single species which leaves these grazing systems vulnerable to disease and insects. Grazing systems so far developed for high production and persistence of cultivated species involve short periods of intense grazing followed by long periods of recovery. Similar management may be necessary in the arid and semi-arid rangelands where palatable browse species are in decline

    Volunteer satisfaction in sports clubs: A multilevel analysis in 10 European countries

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    Regular voluntary engagement is a basic resource for sports clubs that may also promote social cohesion and active citizenship. The satisfaction of volunteers is an imperative factor in this engagement, and the purpose of this article is to explore individual and organizational determinants of volunteer satisfaction in sports clubs. Theoretically, our study builds on the actor-theory concepts where volunteer satisfaction depends on subjective evaluations of expectations and experiences in a sports club (‘logic of situation’), so that positive evaluations lead to higher satisfaction and, hopefully, retention of volunteers. This research uses a sample of 8131 volunteers from 642 sports clubs in 10 European countries, and is the first analysis to combine determinants at the level of the club and the volunteer (multilevel). Results show that the most important determinants of satisfaction are the conditions of volunteering (recognition, support, leadership and material incentives) and the workload of volunteers. Surprisingly, club characteristics, size or having paid staff are not significant determinants of volunteer satisfaction. The results of this analysis can assist more effective volunteer management in sports clubs that are facing challenges of individualization and professionalization

    Genetic Determinants of Time Perception Mediated by the Serotonergic System

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    Background: The present study investigates neurobiological underpinnings of individual differences in time perception. Methodology: Forty-four right-handed Russian Caucasian males (18–35 years old) participated in the experiment. The polymorphism of the genes related to the activity of serotonin (5-HT) and dopamine (DA)-systems (such as 5-HTT, 5HT2a, MAOA, DAT, DRD2, COMT) was determined upon the basis of DNA analysis according to a standard procedure. Time perception in the supra-second range (mean duration 4.8 s) was studied, using the duration discrimination task and parametric fitting of psychometric functions, resulting in individual determination of the point of subjective equality (PSE). Assuming the ‘dual klepsydra model ’ of internal duration representation, the PSE values were transformed into equivalent values of the parameter k (kappa), which is a measure of the ‘loss rate ’ of the duration representation. An association between time representation parameters (PSE and k, respectively) and 5-HT-related genes was found, but not with DArelated genes. Higher ‘loss rate ’ (k) of the cumulative duration representation were found for the carriers of genotypes characterized by higher 5-HT transmission, i.e., 1) lower 5-HT reuptake, known for the 5-HTTLPR SS polymorphism compared with LL, 2) lower 5-HT degradation, described for the ‘low expression ’ variant of MAOA VNTR gene compared with ‘high expression ’ variant, and 3) higher 5-HT2a receptor density, proposed for the TT polymorphism of 5-HT2a T102C gene compared with CC

    A novel platform to enable the high-throughput derivation and characterization of feeder-free human iPSCs

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    Human induced pluripotent stem cells (hiPSCs) hold enormous potential, however several obstacles impede their translation to industrial and clinical applications. Here we describe a platform to efficiently generate, characterize and maintain single cell and feeder-free (FF) cultured hiPSCs by means of a small molecule cocktail media additive. Using this strategy we have developed an effective multiplex sorting and high-throughput selection platform where individual clonal hiPSC lines are readily obtained from a pool of candidate clones, expanded and thoroughly characterized. By promoting survival and self-renewal, the selected hiPSC clones can be rapidly expanded over multiple FF, single-cell passages while maintaining their pluripotency and genomic stability as demonstrated by trilineage differentiation, karyotype and copy number variation analysis. This study provides a robust platform that increases efficiency, throughput, scale and quality of hiPSC generation and facilitates the industrial and clinical use of iPSC technology
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