1,509 research outputs found

    On the Effects of Projection on Morphology

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    We study the effects of projection of three-dimensional (3D) data onto the plane of the sky by means of numerical simulations of turbulence in the interstellar medium including the magnetic field, parameterized cooling and diffuse and stellar heating, self-gravity and rotation. We compare the physical-space density and velocity distributions with their representation in position-position-velocity (PPV) space (``channel maps''), noting that the latter can be interpreted in two ways: either as maps of the column density's spatial distribution (at a given line-of-sight (LOS) velocity), or as maps of the spatial distribution of a given value of the LOS velocity (weighted by density). This ambivalence appears related to the fact that the spatial and PPV representations of the data give significantly different views. First, the morphology in the channel maps more closely resembles that of the spatial distribution of the LOS velocity component than that of the density field, as measured by pixel-to-pixel correlations between images. Second, the channel maps contain more small-scale structure than 3D slices of the density and velocity fields, a fact evident both in subjective appearance and in the power spectra of the images. This effect may be due to a pseudo-random sampling (along the LOS) of the gas contributing to the structure in a channel map: the positions sampled along the LOS (chosen by their LOS velocity) may vary significantly from one position in the channel map to the next.Comment: 6 figures. To appear in the March 20th volume in Ap

    Retail Salesperson’s Influence on India’s Lonely Consumers

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    Many consumers in India experience loneliness and social isolation. Some may resort to shopping for a social experience, attempting to mitigate or remedy their situation. Looking to this key emerging market, we investigate how emotional loneliness, social loneliness, and social isolation influence enjoyment of social interaction with an in-store salesperson (ESIS). We also consider whether adaptive selling and predisposition to comply with salesperson input (PCSI) influence consumers’ trust in salesperson, purchase intention, and retail patronage. We utilize partial least squares structural equation modeling with a sample of 303 Indian consumers. Additionally, we provide two importance-performance mapping analyses, which offer additional insights for retail managers trying to prioritize attention to constructs driving improvement of ESIS and PCSI. In this study, the degree of consumer loneliness and social isolation were proposed to influence Indian consumers’ enjoyment of social interaction with an in-store salesperson (ESIS), Ă  la shopping as a social experience (Hu & Jasper, 2006; Jayasankaraprasad & Kathyayani, 2014; Rajamma et al., 2010). As posited and supported, two varieties of loneliness—emotional (EL) and social (SE)—along with social isolation (SI) were shown to be positively associated with Indian consumers’ predisposition to comply with salesperson input (PCSI). Moreover, adaptive selling, which exhibited a positive relationship with PCSI, was propounded to demonstrate a salutary impact on three outcome variables: consumer trust in salesperson (TRUST), consumer purchase intention (PI), and consumer retail patronage (PATRON). Key values for variance explained (R2), relationship strength and direction (ÎČ), effect size (f2), and predictive relevance (Q2) as well as our two importance-performance map analyses underscore the quality of the model presented. The findings suggest that consumers’ perceptions of loneliness and isolation can lead them to seek out social experiences that specifically involve visiting stores and interacting with salespeople. Additionally, given Indian consumers’ realization of a store’s function and a salesperson’s primary purpose, seemingly consumers anticipate their willingness to be influenced by product recommendations and other inputs from salespersons. If, over time, social relationships develop between consumers and salespersons, discrete transactions can evolve or graduate into more regular interactions that enhance trust, purchase intention, and retail patronage. At present, there is relatively little research that deals with lonely and/or socially isolated consumers in the world’s emerging markets. For countries such as India, most scholarship on loneliness relates almost exclusively to elderly persons or youth (Bhatia et al., 2007; Bowker & Raja, 2011; Tiwari, 2013; Upmanyu, Sehgal, & Upmanyu, 1994), providing very few insights into the scale or impact of loneliness for adult consumers and the middle class. This study is step towards bridging the research gaps in this area

    A Randomized, Double-Blinded, Placebo-Controlled, Cross Over Study Evaluating the Efficacy and Safety of Timolol Ophthalmic Solution as an Acute Treatment of Migraine

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    Introduction. Daily oral beta-adrenoreceptor antagonist has been shown to be effective in preventing migraine headaches. Timolol 0.5% ophthalmic solution is a non-selective beta-adrenoreceptor antago- nist, where the primary use is for glaucoma. There have been case reports that timolol is effective in aborting or improving an acute migraine headache. The objective of this study was to assess the efficacy (decrease of ≄ 50% in pain scale at 120 minutes) of timolol 0.5% ophthalmic solution compared to placebo in acute treatment of migraine headache. Methods.We performed a randomized, double-blind, crossover, placebo-controlled, study. Study entry criteria required subjects to have one to eight migraine episodes per month. The primary outcome was comparison of the change in a visual analog pain scale (VAS) at 120 minutes after taking the study medication. Study subjects were given a pain scale with a range of 1 (no pain) to 10 (most severe pain) to complete after onset of migraine but before administration of study drops and 120 minutes after administration of study drops. Improve- ment was defined as a ≄ 50% decrease in pain scale. Results. Nineteen subjects completed the study and were used for analysis. The primary outcome changes in pain scale, 120 minutes after dose, showed a similar decrease for placebo and drug with a slightly wider 95% CI for placebo. Six subjects in each arm experi- enced a ≄ 50% decrease in pain scale. Conclusion. These results support that timolol 0.5% ophthalmic solution is not an efficacious treatment for acute migraine headache

    The calcium current in inner segments of rods from the salamander (Ambystoma tigrinum) retina.

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    Solitary rod inner segments were isolated from salamander retinae. Their Ca current was studied with the 'whole-cell, gigaseal' technique (Hamill, Marty, Neher, Sakmann & Sigworth, 1981). The soluble constituents of the cytoplasm exchanged with the solution in the pipette. The external solution could be changed during continuous perfusion. Membrane voltage was controlled with a voltage clamp. After permeant ions other than Ca were replaced with impermeant ions (i.e. tetraethylammonium as a cation, and aspartate or methanesulphonate as an anion), an inward current remained. It activated at approximately -40 mV, reached a maximum at approximately 0 mV, and decreased as the membrane was further depolarized. The size of the current increased when Ba was substituted for external Ca. The current was blocked when Ca was replaced with Co. The voltage at which the current was half-maximum shifted from approximately -22 to -31 mV during the initial 3 min of an experiment. The maximum amplitude of the current continuously declined during the entire course of an experiment. The time course for activation of the Ca current following a step of depolarization could be described by the sum of two exponentials. The time constant of the slower exponential was voltage dependent. Deactivation following repolarization could also be described by the sum of two exponentials. Both time constants for deactivation were independent of voltage (between -30 and 0 mV) and faster than the slower time constant for activation. When the internal Ca concentration was buffered by 10 mM-EGTA, the Ca current did not inactivate during several seconds of maintained depolarization. When the concentration of EGTA was reduced to 0.1 mM, the Ca current declined and the membrane conductance decreased during several seconds of maintained depolarization. This inactivation was incomplete and only occurred after a substantial quantity of Ca entered. Following repolarization the Ca conductance recovered from inactivation. In contrast, the continuous decline observed during the course of an experiment (item 3) was not reversible. The difference suggests that inactivation and the decline are distinct processes

    Option pricing of earnings announcement risks

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    This paper uses option prices to learn about the equity price uncertainty surrounding information released on earnings announcement dates. To do this, we introduce reduced-form models and estimators to separate price uncertainty regarding earnings announcements from normal day-to-day volatility. Empirically, we find strong support for the importance of earnings announcements. We find that the anticipated price uncertainty is quantitatively large, varies across time, and is informative about the future return volatility. Finally, we quantify the impact of earnings announcements on formal option pricing models

    Functional Projections of Predicates: Experimental Evidence from Coordinate Structure Processing

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    This paper reports the results of six experiments involving an on-line self-paced reading task that examine the processing of coordinate small clause predicate phrases versus coordinated arguments NPs. The results have particular significance for the analysis of small clause complement constructions, and support accounts wherein the small clause complement has an Agr projection associated with it. An adequate explanation of the processing of small clause coordination is shown to motivate a new parsing principle, Coordination Feature-matching, which accounts for the longer reading times observed for the coordination of predicates in small clause complements

    The Probability Distribution Function of Column Density in Molecular Clouds

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    (Abridged) We discuss the probability distribution function (PDF) of column density resulting from density fields with lognormal PDFs, applicable to isothermal gas (e.g., probably molecular clouds). We suggest that a ``decorrelation length'' can be defined as the distance over which the density auto-correlation function has decayed to, for example, 10% of its zero-lag value, so that the density ``events'' along a line of sight can be assumed to be independent over distances larger than this, and the Central Limit Theorem should be applicable. However, using random realizations of lognormal fields, we show that the convergence to a Gaussian is extremely slow in the high- density tail. Thus, the column density PDF is not expected to exhibit a unique functional shape, but to transit instead from a lognormal to a Gaussian form as the ratio η\eta of the column length to the decorrelation length increases. Simultaneously, the PDF's variance decreases. For intermediate values of η\eta, the column density PDF assumes a nearly exponential decay. We then discuss the density power spectrum and the expected value of η\eta in actual molecular clouds. Observationally, our results suggest that η\eta may be inferred from the shape and width of the column density PDF in optically-thin-line or extinction studies. Our results should also hold for gas with finite-extent power-law underlying density PDFs, which should be characteristic of the diffuse, non-isothermal neutral medium (temperatures ranging from a few hundred to a few thousand degrees). Finally, we note that for η≳100\eta \gtrsim 100, the dynamic range in column density is small (â‰Č\lesssim a factor of 10), but this is only an averaging effect, with no implication on the dynamic range of the underlying density distribution.Comment: 13 pages, 7 figures (10 postscript files). Accepted in ApJ. Eliminated implication that ratio of column length to correlation length necessarily increases with resolution, and thus that 3D simulations are unresolved. Added discussion of dependence of autocorrelation function with parameters of the turbulenc

    Electromagnetic form factors of charged and neutral kaons in an extended vector-meson-dominance model

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    A model is developed for electromagnetic form factors of the charged and neutral K-mesons. The formalism is based on ChPT Lagrangians with vector mesons. The form factors, calculated without fitting parameters, are in a good agreement with experiment for space-like and time-like photon momenta. Contribution of the two-kaon channels to the muon anomalous magnetic moment a_\mu is calculated.Comment: 23 pages, 11 figures, accepted for publication in Eur. Phys. J.
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