299 research outputs found

    Small Deviations for Time-Changed Brownian Motions and Applications to Second-Order Chaos

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    We prove strong small deviations results for Brownian motion under independent time-changes satisfying their own asymptotic criteria. We then apply these results to certain stochastic integrals which are elements of second-order homogeneous chaos.Comment: 23 page

    Zinc Finger Targeter (ZiFiT): an engineered zinc finger/target site design tool

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    Zinc Finger Targeter (ZiFiT) is a simple and intuitive web-based tool that facilitates the design of zinc finger proteins (ZFPs) that can bind to specific DNA sequences. The current version of ZiFiT is based on a widely employed method of ZFP design, the ‘modular assembly’ approach, in which pre-existing individual zinc fingers are linked together to recognize desired target DNA sequences. Several research groups have described experimentally characterized zinc finger modules that bind many of the 64 possible DNA triplets. ZiFiT leverages the combined capabilities of three of the largest and best characterized module archives by enabling users to select fingers from any of these sets. ZiFiT searches a query DNA sequence for target sites for which a ZFP can be designed using modules available in one or more of the three archives. In addition, ZiFiT output facilitates identification of specific zinc finger modules that are publicly available from the Zinc Finger Consortium. ZiFiT is freely available at http://bindr.gdcb.iastate.edu/ZiFiT/

    Anisotropic winds from close-in extra-solar planets

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    We present two-dimensional hydrodynamic models of thermally driven winds from highly irradiated, close-in extra-solar planets. We adopt a very simple treatment of the radiative heating processes at the base of the wind, and instead focus on the differences between the properties of outflows in multidimensions in comparison to spherically symmetric models computed with the same methods. For hot (T > 2 x 10^{4} K) or highly ionized gas, we find strong (supersonic) polar flows are formed above the planet surface which produce weak shocks and outflow on the night-side. In comparison to a spherically symmetric wind with the same parameters, the sonic surface on the day-side is much closer to the planet surface in multidimensions, and the total mass loss rate is reduced by almost a factor of four. We also compute the steady-state structure of interacting planetary and stellar winds. Both winds end in a termination shock, with a parabolic contact discontinuity which is draped over the planet separating the two shocked winds. The planetary wind termination shock and the sonic surface in the wind are well separated, so that the mass loss rate from the planet is essentially unaffected. However, the confinement of the planetary wind to the small volume bounded by the contact discontinuity greatly enhances the column density close to the planet, which might be important for the interpretation of observations of absorption lines formed by gas surrounding transiting planets.Comment: ApJ accepte

    Young Adult E-Cigarette Exposure: Implications for Policy and Prevention

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    Objective. The purpose of this study is to examine factors associated with e-cigarette use among college students to better understand their behavior. Using Ajzen’s Reasoned Action Approach, this study sought to better understanding the influence of attitudes, Social norms, and perceived behavioral controls (PBCs) on college students’ intention to try e-cigarettes (even one puff) in the next 30 days. Methodology. This study employed three phases for a mixed methods design that took place between December 2015 and April 2016. Phase 1 used Middlestadt’s salient belief elicitation procedure to capture responses through an open ended survey (n=58). Phase 2, a pilot sample (n=49), was employed to develop and validate a quantitative measure of the underlying RAA constructs, using responses from Phase 1. For Phase 3, a convenience samples (n=499) allowed for the assessment of the measurement models of both the underlying and global constructs of the RAA using exploratory factor analysis, confirmatory factor analysis, and structural equation modeling. All samples consisted of University of Arkansas students between the ages of 18 and 26 years of age. Results. Responses from Phase 1 were used to develop a 162 item measure of the underlying constructs that was reduced to 78 items during Phase 2. During Phase 3, the underlying constructs, attitude, injunctive norms, and PBC were found to significantly predict their respective global measure. Global constructs loaded onto the predicted four factors: intent, attitude, Social norms and PBC, after removing six items. In the final path model, global constructs attitude (.27, p Conclusion. The RAA allows for a better understanding of the values and beliefs people have about a given behavior and how these beliefs influence behavioral intention. College students’ attitudes toward e-cigarettes (e.g., cessation device, fear of addiction) may influence their intention to try these products. Moreover, disapproving referents (e.g., family, parents, and friends) may discourage the use of e-cigarettes for some college students

    A Mechanism Linking Two Known Vulnerability Factors for Alcohol Abuse: Heightened Alcohol Stimulation and Low Striatal Dopamine D2 Receptors

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    Alcohol produces both stimulant and sedative effects in humans and rodents. In humans, alcohol abuse disorder is associated with a higher stimulant and lower sedative responses to alcohol. Here, we show that this association is conserved in mice and demonstrate a causal link with another liability factor: low expression of striatal dopamine D2 receptors (D2Rs). Using transgenic mouse lines, we find that the selective loss of D2Rs on striatal medium spiny neurons enhances sensitivity to ethanol stimulation and generates resilience to ethanol sedation. These mice also display higher preference and escalation of ethanol drinking, which continues despite adverse outcomes. We find that striatal D1R activation is required for ethanol stimulation and that this signaling is enhanced in mice with low striatal D2Rs. These data demonstrate a link between two vulnerability factors for alcohol abuse and offer evidence for a mechanism in which low striatal D2Rs trigger D1R hypersensitivity, ultimately leading to compulsive-like drinkingFil: Bocarsly, Miriam E.. National Institutes of Health; Estados UnidosFil: da Silva e Silva, Daniel. National Institutes of Health; Estados UnidosFil: Kolb, Vanessa. National Institutes of Health; Estados UnidosFil: Luderman, Kathryn D.. National Institutes of Health; Estados UnidosFil: Shashikiran, Sannidhi. National Institutes of Health; Estados UnidosFil: Rubinstein, Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Sibley, David R.. National Institutes of Health; Estados UnidosFil: Dobbs, Lauren K.. National Institutes of Health; Estados Unidos. University of Texas at Austin; Estados UnidosFil: Álvarez, Verónica Alicia. National Institutes of Health; Estados Unido

    Dynamic somite cell rearrangements lead to distinct waves of myotome growth

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    The myogenic precursors responsible for muscle growth in amniotes develop from thedermomyotome, an epithelium at the external surface of the somite. In teleosts, themyogenic precursors responsible for growth have not been identified. We have usedsingle cell lineage labeling in zebrafish to show that anterior border cells of epithelialsomites are myogenic precursors responsible for zebrafish myotome growth. These cellsmove to the external surface of the embryonic myotome and express the transcriptionfactor Pax7. Some remain on the external surface and some incorporate into the fastmyotome, apparently by moving between differentiated slow fibres. The posterior cellsof the somite, in contrast, elongate into medial muscle fibres. The surprising movementof the anterior somite cells to the external somite surface transforms a segmentallyrepeated arrangement of myogenic precursors into a medio-lateral arrangement similar tothat seen in amniotes.Fil: Stellabotte, Frank. Ohio Wesleyan University.; Estados UnidosFil: Dobbs McAuliffe, Betsy. Ohio Wesleyan University.; Estados UnidosFil: Fernandez, Daniel Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina. Universidad Nacional de Tierra del Fuego; ArgentinaFil: Feng, Xuesong. Ohio Wesleyan University.; Estados UnidosFil: Devoto, Stephen Henry. Ohio Wesleyan University.; Estados Unido
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