3,147 research outputs found
Understanding the Entrepreneur: An Index of Entrepreneurial Success
A measure of entrepreneur success is important to identify current and future successful ventures, to further our understanding of the entrepreneurial process and to guide public policies to improve the success rate of start-ups. In this paper we propose an index of entrepreneur success that accommodates multiple inputs and outputs, that is predicated on inputs and that mitigates the impact of outliers. We relate the index to characteristics of the entrepreneur and the venture: age, experience, gender, race, competitive advantage, education, and birthplace. The data are from the Kauffman Firm Survey. The index is calculated for 2,863 firms in 2006.entrepreneur, Kauffman Survey, Financial Economics, Productivity Analysis,
The Impact of Age on the Ability to Perform under Pressure: Golfers on the PGA Tour
This paper is about aging and the ability to perform under pressure on the PGA tour. Performance increases with golfing skill, but may first increase and then decrease with age as experience interacts with changes in physical condition. Similarly, mental fortitude or the ability of a golfer to perform under pressure may first increase and then decrease with age as experience interacts with changes in the ability to concentrate. Net performance on the tour is the result of both physical golfing skill and the ability to perform under pressure. We control for changes in physical skill and focus on the mental side of the game. The role of experience suggests an inverted U shaped relationship between age and mental performance that could vary significantly across golfers. We use Order-m FDH to calculate a measure of performance under pressure, and we confirm an inverted U-shaped curve with age. Along the way, we examine the ability to perform under pressure at the level of the individual golfer.age, efficiency, order-m FDH, golf, performance under pressure, Productivity Analysis,
Funktionelle Magnetresonanzbildgebung des Verdauungstrakts: Klinische Anwendungsmöglichkeiten?
Zusammenfassung: Die Magnetresonanztomographie (MRT) stellt eine vielseitige bildgebende Methode in der Medizin dar, fĂŒr welche ein Spektrum neuer diagnostischer Optionen entwickelt wurde. Neben der in der klinischen Praxis etablierten Darstellung von Organstrukturen, wird die MRT zunehmend zur Bildgebung humaner Organfunktionen wie zum Beispiel des Herzen und des zentralen Nervensystems herangezogen. Der Einsatz zur funktionellen Bildgebung des Verdauungstrakts ist neuartig und erfolgt an wenigen Zentren im Bereich der Grundlagen- und klinischen Forschung. Die hochauflösende kontrastreiche schnelle Bildgebung, die fehlende Belastung durch ionisierende Strahlung und die UntersucherunabhĂ€ngigkeit in der Bildakquisition und Analyse machen die MRT zu einer idealen Methode der Funktionsdiagnostik des Verdauungstrakts. In dieser Ăbersicht werden gegenwĂ€rtige Anwendungen der MRT in der gastroenterolgischen Funktionsdiagnostik vorgestellt und mit herkömmlichen diagnostischen Methoden vergliche
Text-based Editing of Talking-head Video
Editing talking-head video to change the speech content or to remove filler words is challenging. We propose a novel method to edit talking-head video based on its transcript to produce a realistic output video in which the dialogue of the speaker has been modified, while maintaining a seamless audio-visual flow (i.e. no jump cuts). Our method automatically annotates an input talking-head video with phonemes, visemes, 3D face pose and geometry, reflectance, expression and scene illumination per frame. To edit a video, the user has to only edit the transcript, and an optimization strategy then chooses segments of the input corpus as base material. The annotated parameters corresponding to the selected segments are seamlessly stitched together and used to produce an intermediate video representation in which the lower half of the face is rendered with a parametric face model. Finally, a recurrent video generation network transforms this representation to a photorealistic video that matches the edited transcript. We demonstrate a large variety of edits, such as the addition, removal, and alteration of words, as well as convincing language translation and full sentence synthesis
Tannic Acid Effects on Raphanus Raphanistrum Root Acid Phospatase
Author Institution: Department of Biology and Department of Chemistry, Hiram CollegeThe effects of tannic acid (TA) on acid phosphatase (APase) (E.C.3.1.3-2) from root extracts of fertilized or unfertilized Raphanus raphanistrum plants were examined. TA inhibited APase activity non-competitively; Vmax was reduced, but the apparent K^ was unaffected in the presence of added TA. Endogenous tannin content ranged between 0.26 and 0.56 (Imoleg fresh weight * of root tissue. Enzyme activity data was extrapolated to provide estimates of activity in the absence of any TA; uncorrected APase activity of R. raphanistrum was underestimated by an average of 25%. Addition of polyvinylpyrrolidone (PVP) did not affect measured enzyme rates in a consistent manner
PatientâDefined Goals for the Treatment of Severe Aortic Stenosis: A Qualitative Analysis
Patients with severe aortic stenosis (AS) at high risk for aortic valve replacement are a unique population with multiple treatment options, including medical therapy, surgical aortic valve replacement and transcatheter aortic valve replacement (TAVR). Traditionally, in elderly populations, goals of treatment may favour quality of life over survival. Professional guidelines recommend that clinicians engage patients in shared decision making, a process that may lead to decisions more aligned with patient-defined goals of care. Goals of care for high-risk patients with AS are not well defined in the literature, and patient-reported barriers to shared decision making highlight the need for explicit encouragement from clinicians for patient involvement
Monte Carlo Simulations for Ghost Imaging Based on Scattered Photons
X-ray based imaging modalities are widely used in research, industry, and in
the medical field. Consequently, there is a strong motivation to improve their
performances with respect to resolution, dose, and contrast. Ghost imaging (GI)
is an imaging technique in which the images are reconstructed from measurements
with a single-pixel detector using correlation between the detected intensities
and the intensity structures of the input beam. The method that has been
recently extended to X-rays provides intriguing possibilities to overcome
several fundamental challenges of X-ray imaging. However, understanding the
potential of the method and designing X-ray GI systems pose challenges since in
addition to geometric optic effects, radiation-matter interactions must be
considered. Such considerations are fundamentally more complex than those at
longer wavelengths as relativistic effects such as Compton scattering become
significant. In this work we present a new method for designing and
implementing GI systems using the particle transport code FLUKA, that rely on
Monte Carlo (MC) sampling. This new approach enables comprehensive
consideration of the radiation-matter interactions, facilitating successful
planning of complex GI systems. As an example of an advanced imaging system, we
simulate a high-resolution scattered photons GI technique
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Higher measured than modeled ozone production at increased NOx levels in the Colorado Front Range
Abstract. Chemical models must correctly calculate the ozone formation rate, P(O3), to accurately predict ozone levels and to test mitigation strategies. However, air quality models can have large uncertainties in P(O3) calculations, which can create uncertainties in ozone forecasts, especially during the summertime when P(O3) is high. One way to test mechanisms is to compare modeled P(O3) to direct measurements. During summer 2014, the Measurement of Ozone Production Sensor (MOPS) directly measured net P(O3) in Golden, CO, approximately 25âŻkm west of Denver along the Colorado Front Range. Net P(O3) was compared to rates calculated by a photochemical box model that was constrained by measurements of other chemical species and that used a lumped chemical mechanism and a more explicit one. Median observed P(O3) was up to a factor of 2 higher than that modeled during early morning hours when nitric oxide (NO) levels were high and was similar to modeled P(O3) for the rest of the day. While all interferences and offsets in this new method are not fully understood, simulations of these possible uncertainties cannot explain the observed P(O3) behavior. Modeled and measured P(O3) and peroxy radical (HO2 and RO2) discrepancies observed here are similar to those presented in prior studies. While a missing atmospheric organic peroxy radical source from volatile organic compounds co-emitted with NO could be one plausible solution to the P(O3) discrepancy, such a source has not been identified and does not fully explain the peroxy radical modelâdata mismatch. If the MOPS accurately depicts atmospheric P(O3), then these results would imply that P(O3) in Golden, CO, would be NOx-sensitive for more of the day than what is calculated by models, extending the NOx-sensitive P(O3) regime from the afternoon further into the morning. These results could affect ozone reduction strategies for the region surrounding Golden and possibly other areas that do not comply with national ozone regulations. Thus, it is important to continue the development of this direct ozone measurement technique to understand P(O3), especially under high-NOx regimes
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