3,116 research outputs found

    Investment under ambiguity with the best and worst in mind

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    Recent literature on optimal investment has stressed the difference between the impact of risk and the impact of ambiguity - also called Knightian uncertainty - on investors' decisions. In this paper, we show that a decision maker's attitude towards ambiguity is similarly crucial for investment decisions. We capture the investor's individual ambiguity attitude by applying alpha-MEU preferences to a standard investment problem. We show that the presence of ambiguity often leads to an increase in the subjective project value, and entrepreneurs are more eager to invest. Thereby, our investment model helps to explain differences in investment behavior in situations which are objectively identical

    Progressive Structural Defects in Canine Centronuclear Myopathy Indicate a Role for HACD1 in Maintaining Skeletal Muscle Membrane Systems

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    Mutations in HACD1/PTPLA cause recessive congenital myopathies in humans and dogs. Hydroxyacyl-coA dehydratases are required for elongation of very long chain fatty acids, and HACD1 has a role in early myogenesis, but the functions of this striated muscle-specific enzyme in more differentiated skeletal muscle remain unknown. Canine HACD1 deficiency is histopathologically classified as a centronuclear myopathy (CNM). We investigated the hypothesis that muscle from HACD1-deficient dogs has membrane abnormalities in common with CNMs with different genetic causes. We found progressive changes in tubuloreticular and sarcolemmal membranes and mislocalized triads and mitochondria in skeletal muscle from animals deficient in HACD1. Furthermore, comparable membranous abnormalities in cultured HACD1-deficient myotubes provide additional evidence that these defects are a primary consequence of altered HACD1 expression. Our novel findings, including T-tubule dilatation and disorganization, associated with defects in this additional CNM-associated gene provide a definitive pathophysiologic link with these disorders, confirm that dogs deficient in HACD1 are relevant models, and strengthen the evidence for a unifying pathogenesis in CNMs via defective membrane trafficking and excitation-contraction coupling in muscle. These results build on previous work by determining further functional roles of HACD1 in muscle and provide new insight into the pathology and pathogenetic mechanisms of HACD1 CNM. Consequently, alterations in membrane properties associated with HACD1 mutations should be investigated in humans with related phenotypes

    An Analysis of Prosthodontic Research Productivity: Geographic, Economic, and Collaborative Perspective

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    Purpose: This study evaluated the quantity of prosthodontic literature produced globally by continent in three prosthodontic journals over a 10‐year period, 1998–2008. Prosthodontic research productivity relative to economic status of countries and collaboration among countries grouped by economic status was assessed. Materials and Methods: Three peer‐reviewed prosthodontic journals were used for the analysis of articles published in 1998, 2003, and 2008: The Journal of Prosthetic Dentistry, International Journal of Prosthodontics , and Journal of Prosthodontics . The country of every author listed for each included article was recorded. The number of articles published by each continent and each country was reported. Countries were grouped according to the World Bank economic classification system, and the number of articles published by each economic class was found. Results: The majority of publications over the 10‐year period were produced in Asia (Japan), Europe (Germany), and North America (USA). Productivity declined by 14.4% in high‐income countries while it increased in upper middle‐, lower middle‐, and low‐income countries. The majority of publications written by upper and lower middle‐ and low‐income countries were independent works. Articles resulting from collaboration increased over time for all economic classes of countries. Conclusions: The origins of prosthodontic literature are becoming more geographically and economically diverse, with increased contributions from Africa, Asia, and South America, and middle‐ and low‐income countries between 1998 and 2008. Collaboration between high‐income countries and the other economic group countries increased over time.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90374/1/j.1532-849X.2011.00776.x.pd

    Recent developments in chemical reactivity of N,N-dimethylenamino ketones as synthons for various heterocycles

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    The current review presents recent progress in the utility of N,N-dimethyl enaminones as building blocks for a diverse range of acyclic, carbocyclic, five- and six-membered heterocyclic a broad range of heterocyclic and fused heterocyclic derivatives. Most importantly, these N,N-dimethyl analogues have proven to be of biological interest and provide an access to new class of biologically active heterocyclic compounds for biomedical applications. All of these topics are drawn from the recent literature till 2016

    Explosive Nucleosynthesis: What we learned and what we still do not understand

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    This review touches on historical aspects, going back to the early days of nuclear astrophysics, initiated by B2^2FH and Cameron, discusses (i) the required nuclear input from reaction rates and decay properties up to the nuclear equation of state, continues (ii) with the tools to perform nucleosynthesis calculations and (iii) early parametrized nucleosynthesis studies, before (iv) reliable stellar models became available for the late stages of stellar evolution. It passes then through (v) explosive environments from core-collapse supernovae to explosive events in binary systems (including type Ia supernovae and compact binary mergers), and finally (vi) discusses the role of all these nucleosynthesis production sites in the evolution of galaxies. The focus is put on the comparison of early ideas and present, very recent, understanding.Comment: 11 pages, to appear in Springer Proceedings in Physics (Proc. of Intl. Conf. "Nuclei in the Cosmos XV", LNGS Assergi, Italy, June 2018

    MAPping out distribution routes for kinesin couriers

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    In the crowded environment of eukaryotic cells, diffusion is an inefficient distribution mechanism for cellular components. Long-distance active transport is required and is performed by molecular motors including kinesins. Furthermore, in highly polarized, compartmentalized and plastic cells such as neurons, regulatory mechanisms are required to ensure appropriate spatio-temporal delivery of neuronal components. The kinesin machinery has diversified into a large number of kinesin motor proteins as well as adaptor proteins that are associated with subsets of cargo. However, many mechanisms contribute to the correct delivery of these cargos to their target domains. One mechanism is through motor recognition of subdomain-specific microtubule (MT) tracks, sign-posted by different tubulin isoforms, tubulin post-translational modifications (PTMs), tubulin GTPase activity and MT associated proteins (MAPs). With neurons as a model system, a critical review of these regulatory mechanisms is presented here, with particular focus on the emerging contribution of compartmentalised MAPs. Overall, we conclude that – especially for axonal cargo – alterations to the MT track can influence transport, although in vivo, it is likely that multiple track-based effects act synergistically to ensure accurate cargo distribution

    Smc5/6 coordinates formation and resolution of joint molecules with chromosome morphology to ensure meiotic divisions

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    During meiosis, Structural Maintenance of Chromosome (SMC) complexes underpin two fundamental features of meiosis: homologous recombination and chromosome segregation. While meiotic functions of the cohesin and condensin complexes have been delineated, the role of the third SMC complex, Smc5/6, remains enigmatic. Here we identify specific, essential meiotic functions for the Smc5/6 complex in homologous recombination and the regulation of cohesin. We show that Smc5/6 is enriched at centromeres and cohesin-association sites where it regulates sister-chromatid cohesion and the timely removal of cohesin from chromosomal arms, respectively. Smc5/6 also localizes to recombination hotspots, where it promotes normal formation and resolution of a subset of joint-molecule intermediates. In this regard, Smc5/6 functions independently of the major crossover pathway defined by the MutLγ complex. Furthermore, we show that Smc5/6 is required for stable chromosomal localization of the XPF-family endonuclease, Mus81-Mms4Eme1. Our data suggest that the Smc5/6 complex is required for specific recombination and chromosomal processes throughout meiosis and that in its absence, attempts at cell division with unresolved joint molecules and residual cohesin lead to severe recombination-induced meiotic catastroph

    Measurement of the CKM Matrix Element Vcb|V_{cb}| from B0D+νB^{0} \to D^{*-} \ell^+ \nu_\ell at Belle

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    We present a new measurement of the CKM matrix element Vcb|V_{cb}| from B0D+νB^{0} \to D^{*-} \ell^+ \nu_\ell decays, reconstructed with the full Belle data set of 711fb1711 \, \rm fb^{-1} integrated luminosity. Two form factor parameterizations, originally conceived by the Caprini-Lellouch-Neubert (CLN) and the Boyd, Grinstein and Lebed (BGL) groups, are used to extract the product F(1)ηEWVcb\mathcal{F}(1)\eta_{\rm EW}|V_{cb}| and the decay form factors, where F(1)\mathcal{F}(1) is the normalization factor and ηEW\eta_{\rm EW} is a small electroweak correction. In the CLN parameterization we find F(1)ηEWVcb=(35.06±0.15±0.56)×103\mathcal{F}(1)\eta_{\rm EW}|V_{cb}| = (35.06 \pm 0.15 \pm 0.56) \times 10^{-3}, ρ2=1.106±0.031±0.007\rho^{2}=1.106 \pm 0.031 \pm 0.007, R1(1)=1.229±0.028±0.009R_{1}(1)=1.229 \pm 0.028 \pm 0.009, R2(1)=0.852±0.021±0.006R_{2}(1)=0.852 \pm 0.021 \pm 0.006. For the BGL parameterization we obtain F(1)ηEWVcb=(34.93±0.23±0.59)×103\mathcal{F}(1)\eta_{\rm EW}|V_{cb}|= (34.93 \pm 0.23 \pm 0.59)\times 10^{-3}, which is consistent with the World Average when correcting for F(1)ηEW\mathcal{F}(1)\eta_{\rm EW}. The branching fraction of B0D+νB^{0} \to D^{*-} \ell^+ \nu_\ell is measured to be B(B0D+ν)=(4.90±0.02±0.16)%\mathcal{B}(B^{0}\rightarrow D^{*-}\ell^{+}\nu_{\ell}) = (4.90 \pm 0.02 \pm 0.16)\%. We also present a new test of lepton flavor universality violation in semileptonic BB decays, B(B0De+ν)B(B0Dμ+ν)=1.01±0.01±0.03 \frac{{\cal B }(B^0 \to D^{*-} e^+ \nu)}{{\cal B }(B^0 \to D^{*-} \mu^+ \nu)} = 1.01 \pm 0.01 \pm 0.03~. The errors correspond to the statistical and systematic uncertainties respectively. This is the most precise measurement of F(1)ηEWVcb\mathcal{F}(1)\eta_{\rm EW}|V_{cb}| and form factors to date and the first experimental study of the BGL form factor parameterization in an experimental measurement

    Angular analysis of B0K(892)0+B^0 \to K^\ast(892)^0 \ell^+ \ell^-

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    We present a measurement of angular observables, P4P_4', P5P_5', P6P_6', P8P_8', in the decay B0K(892)0+B^0 \to K^\ast(892)^0 \ell^+ \ell^-, where +\ell^+\ell^- is either e+ee^+e^- or μ+μ\mu^+\mu^-. The analysis is performed on a data sample corresponding to an integrated luminosity of 711 fb1711~\mathrm{fb}^{-1} containing 772×106772\times 10^{6} BBˉB\bar B pairs, collected at the Υ(4S)\Upsilon(4S) resonance with the Belle detector at the asymmetric-energy e+ee^+e^- collider KEKB. Four angular observables, P4,5,6,8P_{4,5,6,8}' are extracted in five bins of the invariant mass squared of the lepton system, q2q^2. We compare our results for P4,5,6,8P_{4,5,6,8}' with Standard Model predictions including the q2q^2 region in which the LHCb collaboration reported the so-called P5P_5' anomaly.Comment: Conference paper for LHC Ski 2016. SM prediction for P6P_{6}' corrected and reference for arXiv:1207.2753 adde
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