541 research outputs found
An unusual âvenous circleâ of the internal mammary vein encountered during microvascular anastomosis and implications for practice
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 âvenous circleâ
The TullyâFisher relation from SDSS-MaNGA: physical causes of scatter and variation at different radii
The stellar mass TullyâFisher 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 (â€1.3Re) compared to the gas. At 2Re, the relations for the two components are consistent. When accounting for covariances with integrated v/Ï, 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 (â€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
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
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?
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
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
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
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 individualâs 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
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 ârich fantasy lifeâ. 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 âRich Fantasy Lifeâ, via âHostile Beliefs about Womenâ, influences the use of âAggressive Sexual Fantasiesâ. 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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