3,879 research outputs found

    On the Forward-Backward Asymmetry of Leptonic Decays of ttˉt\bar{t} at the Fermilab Tevatron

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    We report on a study of the measurement techniques used to determine the leptonic forward-backward asymmetry of top anti-top quark pairs in Tevatron experiments with a proton anti-proton initial state. Recently it was shown that a fit of the differential asymmetry as a function of qlηlq_{l}\eta_{l} (where qlq_{l} is the charge of the lepton from the cascade decay of the top quarks and ηl\eta_{l} is the final pseudorapidity of the lepton in the detector frame) to a hyperbolic tangent function can be used to extrapolate to the full leptonic asymmetry. We find this empirical method to well reproduce the results from current experiments, and present arguments as to why this is the case. We also introduce two more models, based on Gaussian functions, that better model the qlηlq_{l}\eta_{l} distribution. With our better understanding, we find that the asymmetry is mainly determined by the shift of the mean of the qlηlq_{l}\eta_{l} distribution, the main contribution to the inclusive asymmetry comes from the region around qlηl=1|q_{l}\eta_{l}| = 1, and the extrapolation from the detector-covered region to the inclusive asymmetry is stable via a multiplicative scale factor, giving us confidence in the previously reported experimental results.Comment: 26 pages, 12 figure

    Uncovering the structural diversity of Y(III) naphthalene-2,6-dicarboxylate MOFs through coordination modulation

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    Metal-organic frameworks (MOFs) – network structures built from metal ions and clusters and connecting organic ligands – are typically synthesized by solvothermal self-assembly. For transition metal based MOFs, structural predictability is facilitated by control over coordination geometries and linker connectivity under the principles of isoreticular synthesis. For rare earth MOFs, coordination behaviour is dominated by steric and electronic factors, leading to unpredictable structures and poor control over self-assembly. Herein we show that coordination modulation – the addition of competing ligands into MOF syntheses – offers programmable access to six different Y(III) MOFs all connected by the same naphthalene-2,6-dicarboxylate ligand, despite controlled synthesis of multiple phases from the same metal-ligand combination often being challenging for rare earth MOFs. Four of the materials are isolable in bulk phase purity, three are amenable to rapid microwave synthesis, and the fluorescence sensing ability of one example towards metal cations is reported. The results show that a huge variety of structurally versatile MOFs can potentially be prepared from simple systems, and that coordination modulation is a powerful tool for systematic control of phase behaviour in rare earth MOFs

    Children’s experiences with Child Protection Services: A synthesis of qualitative evidence

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    Background - Research shows that young adults, previously in contact with Child Protection Services (CPS) often have lower overall wellbeing when compared to their peers in the general population. To redress this balance and fulfil children’s right to receive good quality and child-centred services, the child ´s lived experience of the CPS processes and interventions must be better understood. There is research with children about specific aspects of CPS, such as experiences of investigation, out-of-home care, end of intervention and participation. Yet, there is no available synthesis of the literature that would provide a general overview of children’s lived experiences of these services. Objective - The aim of this review was to comprehensively identify, synthesise and analyse the current empirical research that explored children’s overall experiences of Child Protection Services. Method - This is a systematic review and qualitative evidence synthesis of primary studies. A systematic search was conducted using five databases related to social sciences and social work for relevant qualitative publications in English. Using PRISMA, 39 studies were included in this review. A qualitative evidence synthesis was carried out, which entailed extracting, synthesising and thematic analysis of text from the findings section of the included studies. Results -Most of the literature focused on the perceptions of children in out-of-home care. Four main themes emerged that captured these subjective experiences: children described the processes of coming in contact with CPS, their experiences of the CPS intervention or services, their perceptions of the outcomes of the intervention and lastly their perceptions of self, social identity and stigmatisation. Discussion and Conclusion - This review concludes that, from the perspective of the child, clear, understandable and comprehensive information about the CPS process is required so that they can assert their right to participation and protection. Being in CPS is an emotional experience for them, thus emotional as much as physical safety, is needed. A sense of belongingness and self-actualization are as important as food and shelter. This knowledge should be considered in practice to improve both short and long-term outcomes for children in contact with the CPS

    Uncovering the Structural Diversity of Y(III) Naphthalene-2,6-Dicarboxylate MOFs Through Coordination Modulation

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    Metal-organic frameworks (MOFs)—network structures built from metal ions or clusters and connecting organic ligands—are typically synthesized by solvothermal self-assembly. For transition metal based MOFs, structural predictability is facilitated by control over coordination geometries and linker connectivity under the principles of isoreticular synthesis. For rare earth (RE) MOFs, coordination behavior is dominated by steric and electronic factors, leading to unpredictable structures, and poor control over self-assembly. Herein we show that coordination modulation—the addition of competing ligands into MOF syntheses—offers programmable access to six different Y(III) MOFs all connected by the same naphthalene-2,6-dicarboxylate ligand, despite controlled synthesis of multiple phases from the same metal-ligand combination often being challenging for rare earth MOFs. Four of the materials are isolable in bulk phase purity, three are amenable to rapid microwave synthesis, and the fluorescence sensing ability of one example toward metal cations is reported. The results show that a huge variety of structurally versatile MOFs can potentially be prepared from simple systems, and that coordination modulation is a powerful tool for systematic control of phase behavior in rare earth MOFs

    Anything for a Cheerio: Brown Capuchins (\u3cem\u3eSapajus [Cebus] apella\u3c/em\u3e) Consistently Coordinate in an Assurance Game for Unequal Payoffs

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    Unequal outcomes disrupt cooperation in some situations, but this has not been tested in the context of coordination in economic games. To explore this, we tested brown capuchins (Sapajus [Cebus] apella) on a manual version of the Stag Hunt (or Assurance) Game, in which individuals sequentially chose between two options, Stag or Hare, and were rewarded according to their choices and that of their partner. Typically, coordination on Stag results in an equal highest payout, whereas coordinating on Hare results in a guaranteed equal but lower payoff and uncoordinated play results in the lowest payoff when playing Stag. We varied this structure such that one capuchin received double the rewards for the coordinated Stag outcome; thus, it was still both animals\u27 best option, but no longer equally rewarding. Despite the inequality, capuchins coordinated on Stag in 78% of trials, and neither payoff structure nor their partner\u27s choice impacted their decision. Additionally, there was no relationship between self-scratching, a measure of stress in capuchins, and choices. After completing the study, we discovered our reward, cheerios, was sufficiently valuable that in another study, capuchins never refused it, so post hoc we repeated the study using a lower value reward, banana flavored pellets. Capuchins completed only 26% of the pellet trials (compared to 98% with cheerios), constraining our ability to interpret the results, but nonetheless the monkeys showed a decrease in preference for Stag, particularly when they received fewer rewards for the coordinated Stag outcome. These results reinforce capuchins\u27 ability to find coordinated outcomes in the Stag Hunt game, but more work is needed to determine whether the monkeys did not mind the inequality or were unwilling to sacrifice a highly preferred food to rectify it. In either case, researchers should carefully consider the impact of their chosen rewards on subjects\u27 choices

    Understory 2014

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    “Art is the struggle to be, in a particular sort of way, virtuous.” —Iris Murdoch Indeed, when we embark on any creative adventure it is with the purpose of conveying a certain truth; an emotion, an idea that brings us together and reminds us of the innate consciousness that dwells within. Understory is emblematic of this; where individuals intent on honing their craft can join others to become a part of something greater, their work immortalized to become a time capsule. Decades from now a volume of Understory may be discovered on a dusty bookshelf in some forgotten corner and the lucky explorer who finds it shall be enlightened by pages of gold. We, as editors of Understory 2014, have worked very hard this year to put together a journal that showcases the very best of the University of Alaska Anchorage undergraduate student work. We hope you enjoy your journey through this issue as much as we have enjoyed ours. Thank you to the English and Art Departments, for the staff and faculty’s unerring support of our club; to Provost Baker, for seeing and believing in the vision of Understory; and to our club’s faculty advisor, Douglass Bourne, for his guidance and tireless assistance. Finally, thank you to the wonderful students who submit such excellent work each year. Without your passion for the arts, we would not be here.Staff / Letter from the Editors / Glass Blower / Writing / Obsolete Evolution / Permafrost / Phoenix / Untitled / Ratio / Tripping / Abiogenesis / My Heart Beats for You / Meeting of the Fingerprint Lines / You Are No Stranger / Nightmare Fuel / Cane-Sugar / Gossamer Strands / Panthera Gold / Butterfly / A Mantis Too Far / Long and Winding Road / Chasing Shadows / Merisunas / Chequer Grove / Modzilla / Beans / Little Red and Mr. Wolf / In Memoriam, Joel Fletcher Armstrong / Glance / Courage / Uranium Waltz / Danger / Journey to the West / Antumbra / Roaring Like a Lion / Pre-boarding / Untitled / How Do You Say a Word / Fishing for Doom/ Contributor

    Identification of a functional interaction of HMGB1 with Receptor for Advanced Glycation End-products in a model of neuropathic pain

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    Recent studies indicate that the release of high mobility group box 1 (HMGB1) following nerve injury may play a central role in the pathogenesis of neuropathic pain. HMGB1 is known to influence cellular responses within the nervous system via two distinct receptor families; the Receptor for Advanced Glycation End-products (RAGE) and Toll-like receptors (TLRs). The degree to which HMGB1 activates a receptor is thought to be dependent upon the oxidative state of the ligand, resulting in the functional isoforms of all-thiol HMGB1 (at-HMGB1) acting through RAGE, and disufide HMGB1 (ds-HMGB1) interacting with TLR4. Though it is known that dorsal root ganglia (DRG) sensory neurons exposed to HMGB1 and TLR4 agonists can influence excitation, the degree to which at-HMGB1 signaling through neuronal RAGE contributes to neuropathic pain is unknown. Here we demonstrate that at-HMGB1 activation of nociceptive neurons is dependent on RAGE and not TLR4. To distinguish the possible role of RAGE on neuropathic pain, we characterized the changes in RAGE mRNA expression up to one month after tibial nerve injury (TNI). RAGE mRNA expression in lumbar dorsal root ganglion (DRG) is substantially increased by post-injury day (PID) 28 when compared with sham injured rodents. Protein expression at PID28 confirms this injury-induced event in the DRG. Moreover, a single exposure to monoclonal antibody to RAGE (RAGE Ab) failed to abrogate pain behavior at PID 7, 14 and 21. However, RAGE Ab administration produced reversal of mechanical hyperalgesia on PID28. Thus, at-HMGB1 activation through RAGE may be responsible for sensory neuron sensitization and mechanical hyperalgesia associated with chronic neuropathic pain states
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