541 research outputs found

    An unusual “venous circle” of the internal mammary vein encountered during microvascular anastomosis and implications for practice

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    The internal mammary vessels are commonly used for anastomosis in breast reconstruction. The anatomy when using the 2nd ICS has been shown to be predictable and hence preferentially used by the senior author. We present an unusual case of internal mammary vein bifurcation and immediate confluence forming a ‘venous circle’

    The Tully–Fisher relation from SDSS-MaNGA: physical causes of scatter and variation at different radii

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    The stellar mass Tully–Fisher relation (STFR) and its scatter encode valuable information about the processes shaping galaxy evolution across cosmic time. However, we are still missing a proper quantification of the STFR slope and scatter dependence on the baryonic tracer used to quantify rotational velocity, on the velocity measurement radius and on galaxy integrated properties. We present a catalogue of stellar and ionized gas (traced by H emission) kinematic measurements for a sample of galaxies drawn from the MaNGA Galaxy Survey, providing an ideal tool for galaxy formation model calibration and for comparison with high-redshift studies. We compute the STFRs for stellar and gas rotation at 1, 1.3 and 2 effective radii (Re). The relations for both baryonic components become shallower at 2Re compared to 1Re and 1.3Re. We report a steeper STFR for the stars in the inner parts (≀1.3Re) compared to the gas. At 2Re, the relations for the two components are consistent. When accounting for covariances with integrated v/σ, scatter in the stellar and gas STFRs shows no strong correlation with: optical morphology, star formation rate surface density, tidal interaction strength or gas accretion signatures. Our results suggest that the STFR scatter is driven by an increase in stellar/gas dispersional support, from either external (mergers) or internal (feedback) processes. No correlation between STFR scatter and environment is found. Nearby Universe galaxies have their stars and gas in statistically different states of dynamical equilibrium in the inner parts (≀1.3Re), while at 2Re the two components are dynamically coupled

    GECKOS: Turning galaxy evolution on its side with deep observations of edge-on galaxies

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    We present GECKOS (Generalising Edge-on galaxies and their Chemical bimodalities, Kinematics, and Outflows out to Solar environments), a new ESO VLT/MUSE large program. The main aim of GECKOS is to reveal the variation in key physical processes of disk formation by connecting Galactic Archaeology with integral field spectroscopic observations of nearby galaxies. Edge-on galaxies are ideal for this task: they allow us to disentangle the assembly history imprinted in thick disks and provide the greatest insights into outflows. The GECKOS sample of 35 nearby edge-on disk galaxies is designed to trace the assembly histories and properties of galaxies across a large range of star formation rates, bulge-to-total ratios, and boxy and non-boxy bulges. GECKOS will deliver spatially resolved measurements of stellar abundances, ages, and kinematics, as well as ionised gas metallicities, ionisation parameters, pressure, and inflow and outflow kinematics; all key parameters for building a complete chemodynamical picture of disk galaxies. With these data, we aim to extend Galactic analysis methods to the wider galaxy population, reaping the benefits of detailed Milky Way studies, while probing the diverse mechanisms of galaxy evolution.Comment: 6 pages, 2 figures, Proceedings of IAUS 377, eds. F. Tabatabaei, B. Barbuy, and Y. Tin

    Wave propagation in stereo-lithographical (STL) bone replicas at oblique incidence

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    Comparisons between predictions of a Biot-Allard model allowing for angle-dependent elasticity and angle-and-porosity dependent tortuosity and transmission data obtained at normal incidence on water-saturated replica bones are extended to oblique incidence. The model includes two parameters which are adjusted for best fit at normal incidence. Using the same parameter values, it is found that predictions of the variation of transmitted waveforms with angle through two types of bone replica are in reasonable agreement with data despite the fact that scattering is not included in the theory

    Business experience and start-up size: buying more lottery tickets next time around?

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    This paper explores the determinants of start-up size by focusing on a cohort of 6247 businesses that started trading in 2004, using a unique dataset on customer records at Barclays Bank. Quantile regressions show that prior business experience is significantly related with start-up size, as are a number of other variables such as age, education and bank account activity. Quantile treatment effects (QTE) estimates show similar results, with the effect of business experience on (log) start-up size being roughly constant across the quantiles. Prior personal business experience leads to an increase in expected start-up size of about 50%. Instrumental variable QTE estimates are even higher, although there are concerns about the validity of the instrument

    Antecedents and consequences of effectuation and causation in the international new venture creation process

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    The selection of the entry mode in an international market is of key importance for the venture. A process-based perspective on entry mode selection can add to the International Business and International Entrepreneurship literature. Framing the international market entry as an entrepreneurial process, this paper analyzes the antecedents and consequences of causation and effectuation in the entry mode selection. For the analysis, regression-based techniques were used on a sample of 65 gazelles. The results indicate that experienced entrepreneurs tend to apply effectuation rather than causation, while uncertainty does not have a systematic influence. Entrepreneurs using causation-based international new venture creation processes tend to engage in export-type entry modes, while effectuation-based international new venture creation processes do not predetermine the entry mod

    SNITCH:seeking a simple, informative star formation history inference tool

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    Deriving a simple, analytic galaxy star formation history (SFH) using observational data is a complex task without the proper tool to hand. We therefore present SNITCH, an open source code written in PYTHON, developed to quickly (2 min) infer the parameters describing an analytic SFH model from the emission and absorption features of a galaxy spectrum dominated by star formation gas ionization. SNITCH uses the Flexible Stellar Population Synthesis models of Conroy, Gunn & White (2009), the MaNGA Data Analysis Pipeline and a Markov Chain Monte Carlo method in order to infer three parameters (time of quenching, rate of quenching, and model metallicity) which best describe an exponentially declining quenching history. This code was written for use on the MaNGA spectral data cubes but is customizable by a user so that it can be used for any scenario where a galaxy spectrum has been obtained, and adapted to infer a user defined analytic SFH model for specific science cases. Herein, we outline the rigorous testing applied to SNITCH and show that it is both accurate and precise at deriving the SFH of a galaxy spectra. The tests suggest that SNITCHis sensitive to the most recent epoch of star formation but can also trace the quenching of star formation even if the true decline does not occur at an exponential rate. With the use of both an analytical SFH and only five spectral features, we advocate that this code be used as a comparative tool across a large population of spectra, either for integral field unit data cubes or across a population of galaxy spectra

    Heuristic Reasoning and the Observer's View: The Influence of Example-Availability on ad-hoc Frequency Judgments in Sport

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    Drawing upon evidence from broader social psychology, and an illustrative study of frequency estimation during a simple, sport-specific observe-and-recall task, this paper makes the case for the more thorough investigation of the availability heuristic (Tversky & Kahneman, 1973) on practical state-of-play reasoning in largely observational sporting activities. It is argued that this evidence particularly substantiates a need for a more robust body of research in two primary domains: (a) the gatekeeping tasks pertinent (and usually preliminary) to an individual’s sporting performance such as talent scouting, team selection, and substitution decisions, and (b) the business of officiating in high-tempo environments

    The influence of fantasy proneness, dissociation, and vividness of mental imagery on male's aggressive sexual fantasies

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    Many researchers have studied the prevalence and content of men's aggressive sexual fantasies, including their link with rape-supportive cognition. However, little to no research has examined the link between imaginal ability and the use of such fantasies. Based on existing research and theory, we propose that men who hold hostile beliefs towards women will use aggressive sexual fantasies more often if they possess a greater ability to engage in a ‘rich fantasy life’. Operationally, we argue this involves: (1) a proneness to fantasize in general; (2) an ability to vividly envision mental imagery; and (3) frequent experiences of dissociation. To test this, the present study hypothesized that a latent variable termed ‘Rich Fantasy Life’, via ‘Hostile Beliefs about Women’, influences the use of ‘Aggressive Sexual Fantasies’. A sample of 159 community males was recruited. Each participant completed a measure of fantasy proneness, dissociation, and vividness of mental imagery, along with two measures that assess hostile beliefs about women. Assessing how often the participants fantasized about rape-related and sadistic themes provided a measure of aggressive sexual fantasies. Structural equation modeling (along with bootstrapping procedures) indicated that the data had a very good fit with the hypothesized model. The results offer an important contribution to our understanding of aggressive sexual fantasies, which may have implications for clinical assessment and treatment. The limitations of the study are discussed, along with suggestions for future research
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