27 research outputs found
Asymmetric information and the distribution of trading volume
No full textFunding Information: ☆ We thank an anonymous referee, Anna Bayona, Alex Boulatov, Darwin Choi, Jaewon Choi, Tarun Chordia, Jonathan Cohn, David Easley, Eliezer Fich, Carlos Forner Rodríguez, Thierry Foucault, Bruce Grundy, Alex Gümbel, Sam Hartzmark, Henry Jarva, Dirk Jenter, Pete Kyle, Albert Menkveld, Anna Obizhaeva, Deniz Okat, Conall O'Sullivan, Paolo Pasquariello, Jillian Popadak, Jorg Prokop, David Reiffen, Dagfinn Rime, Francesco Sangiorgi, Enrique Sentana, Andriy Shkilko, Valeri Sokolovski, Sorin Sorescu, Erik Theissen, Ian Tonks, Hugo van Buggenum, Michael Weber, Christian Westheide and participants at the ABFER, CEPR and CUHK Annual Symposium (Hong Kong), the American Economic Association (Chicago), the Eastern Finance Association (Philadelphia), the EBC network, the French Finance Association, the Future of Financial Information conference, the German Finance Association, the SAFE Market Microstructure Conference, the SFM conference (Kaohsiung, Taiwan), the Spanish Finance Association, Aalto University, the Bank of England, the Bank of Finland, Erasmus University Rotterdam, the Higher School of Economics, Hong Kong Baptist University, University of Amsterdam, University of Liverpool, University of Maastricht, University of Toulouse, University of Turku, and VU Amsterdam for constructive comments. We thank Fabian Brunner and Nikolas Breikopf for help with the EDGAR data. Publisher Copyright: © 2023 The AuthorsWe propose the Volume Coefficient of Variation (VCV), the ratio of the standard deviation to the mean of trading volume, as a new and simple measure of information asymmetry in security markets. We use a microstructure model to demonstrate that VCV is strictly increasing in the proportion of informed trade. Empirically, we obtain VCV from daily observations of trading volume and provide extensive evidence supporting the hypothesis that VCV indicates information asymmetry, by studying return reversals, institutional ownership, and extant firm-level measures of asymmetric information in the cross-section of US stocks. Moreover, VCV increases following exogenous reductions in analyst coverage induced by brokerage closures, and steeply decreases around earnings announcements and other information disclosures.Peer reviewe
Two essays on labor and finance
No full textThere is an emerging literature linking finance to employment. My dissertation focuses on a combination of institutional investors, family firms, which are corporate finance topics and layoff decisions--which is a labor economics topic. The first essay examines institutional investors can play an important role on the firm’s layoff decisions. This study uses a hand-collected dataset of employee layoff announcements from 1983 to 2008, to examine the relationship between layoffs and institutional ownership. First, I find that firms with high institutional ownership are more likely to lay off employees. Furthermore, I study the effect of investor horizon on the layoff decisions. I find that the likelihood of layoffs is positively related to ownership by long-term institutional investors who have greater incentives for monitoring that result in layoffs. The propensity to lay off employees is also increasing in public pension fund ownership. Firms with high local institutional ownership are less likely to lay off employees consistent with the presence of local social and political pressure. Finally, I find that the market perceives layoff announcements made by firms with more long-term institutional investors, public pension funds and non-local institutions positively, in comparison with layoffs by firms with more short-term institutional investors, non-public pension funds and local institutions. The second essay explore whether there is difference in employment policy between family firms and non-family firms. Using large hand-collected layoff samples during 2002-2008, I find that family firms are less likely to reduce employees than non-family firms. The lower propensity for layoffs in family firms is robust to a host of controls for firm characteristics and economic conditions. This lower propensity for layoffs is not explained by differences in how family and non-family firms respond to economic difficulties. However, the lower propensity for layoffs in family firms is stronger when 1) the founder owners are in control and 2) when the firm is located in less populated counties. This suggests that managers in family firms provide an implicit contract ensuring job security to employees.Ph.D.Includes bibliographical referencesIncludes vitaby Kihun Ki
Usability and acceptability of a website that provides tailored advice on falls prevention activities for older people
No full textThis article presents the usability and acceptability of a website that provides older people with tailored advice to help motivate them to undertake physical activities that prevent falls. Views on the website from interviews with 16 older people and 26 sheltered housing wardens were analysed thematically. The website was well received with only one usability difficulty with the action plan calendar. The older people selected balance training activities out of interest or enjoyment, and appeared to carefully add them into their current routine. The wardens were motivated to promote the website to their residents, particularly those who owned a computer, had balance problems, or were physically active. However, the participants noted that currently a minority of older people use the Internet. Also, some older people underestimated how much activity was enough to improve balance, and others perceived themselves as too old for the activities
A new self-expandable, nickel-titanium coil stent for esophageal obstruction: A preliminary report
No full textAccounting for changes in the Spanish wage distribution : the role of employment composition effects
No full textDespite a rapid decrease in unemployment and strong GDP and employment growth, real wages barely increased in Spain over the period 1995-2006. An explanation of this lack of growth may rely on employment composition effects derived from structural changes, such as the rise in the weights of employment in the construction and services sectors, the increase in female employment participation, and the arrival of large immigration inflows. Using data from three waves of the Structure of Earnings Survey, we break down observed wage changes into those due to varying worker and job characteristics and variations of the returns to those characteristics. Quantile regressions are used to estimate wage equations at different percentiles and to construct the counterfactual wage distributions that would have been observed had individual and job characteristics remain constant over time. Our main finding is that the lack of growth of Spanish real wages over the period 1995-2006 is mainly due to the decrease of returns to characteristics, specially education and labour market experience, which is more noticeable at the upper deciles of the wage distribution, and not to changes in employment composition, which when taken over a wide set of worker and job characteristics, had positive effects on wagesA pesar de una rápida disminución del desempleo, los salarios reales en España
apenas aumentaron durante el periodo 1995-2006. Una posible explicación de este
comportamiento se refiere a la importancia de los efectos composición derivados de
algunos cambios estructurales, tales como el aumento del peso del empleo en la
construcción y en el sector servicios, el incremento de la participación laboral
femenina, y la llegada masiva de inmigrantes. Utilizando datos de tres olas de la
Encuesta de Estructura Salarial, se descompone la variación salarial observada
durante este periodo en dos componentes, el debido a los cambios en las
características de los puestos de trabajo y de los trabajadores, y el causado por los
cambios en los rendimientos de dichas características. Así, mediante regresiones
cuantílicas que estiman ecuaciones de salarios condicionadas a determinados
percentiles de la distribución salarial, se construyen las distribuciones contrafactuales
que se hubieran observado de haberse mantenido constantes las características de
los puestos de trabajo y de los trabajadores. El principal resultado es que la falta de
crecimiento de los salarios reales en España durante el periodo 1995-2006 se debe,
sobre todo, a la caída de los rendimientos, especialmente de la educación y de la
experiencia laboral en los deciles elevados de la distribución salarial, y no tanto a
cambios en la composición del empleo que, computados sobre un conjunto amplio
de características, tuvieron un efecto global positivo sobre los salarios.First author
acknowledges research funding from the Spanish Ministry of Science and Innovation, Grant No. ECO2009-1116
ASCA and ANCA among Bedouin Arabs with inflammatory bowel disease, the frequency and phenotype correlation
No full textAbstract Background Serological markers used for diagnostic purposes and disease stratification in inflammatory bowel disease. We aimed to investigate the frequency of ASCA and ANCA among Arab Bedouin IBD patients and its relationship to disease phenotype and course. Methods From cohort of 68, 25 Crohn’s disease (CD) and 25 Ulcerative colitis (UC) patients were recruited (72%). ASCA IgG was determined by ELISA assay. Immunofluorescence analysis of ANCA was performed. Results The IgG ASCA was detected in 13 (52%) of the CD patients and in three (12%) UC patients. The prevalence of ANCA among UC patients was positive with 76%, sub-grouped, atypical ANCA in 9 patients (36%), pANCA in six patients (24%) and cANCA in 4 patients (16%). The detection of ASCA among CD patients was found not to be a reliable predictor of young age at diagnosis, gender, ileal involvement, anti-TNF treatment or surgery. UC patients with positive ANCA were younger, mean age 40.2 ± 11.9 compared with 57.3 ± 21.2 (p = 0.03), and diagnosed at a younger age, 29.2 ± 11.8 compared with 43.5 ± 15.3 (p = 0.05). Conclusion The frequency of ASCA among Bedouin CD patients and ANCA among UC patients was high, however ASCA was not found to have a predictive value for disease phenotype or course. Positive ANCA in UC patients was predictive for younger age and age at diagnosis
The JCMT Gould Belt Survey : first results from the SCUBA-2 observations of the Ophiuchus molecular cloud and a virial analysis of its prestellar core population
No full textIn this paper, we present the first observations of the Ophiuchus molecular cloud performed as part of the James Clerk Maxwell Telescope (JCMT) Gould Belt Survey (GBS) with the SCUBA-2 instrument.We demonstratemethods for combining these datawith previous HARP CO, Herschel, and IRAM N2H+ observations in order to accurately quantify the properties of the SCUBA-2 sources in Ophiuchus. We produce a catalogue of all of the sources found by SCUBA-2. We separate these into protostars and starless cores. We list all of the starless cores and perform a full virial analysis, including external pressure. This is the first time that external pressure has been included in this level of detail. We find that the majority of our cores are either bound or virialized. Gravitational energy and external pressure are on average of a similar order of magnitude, but with some variation from region to region. We find that cores in the Oph A region are gravitationally bound prestellar cores, while cores in the Oph C and E regions are pressure-confined. We determine that N2H+ is a good tracer of the bound material of prestellar cores, although we find some evidence for N2H+ freeze-out at the very highest core densities.We find that non-thermal linewidths decrease substantially between the gas traced by C18O and that traced by N2H+, indicating the dissipation of turbulence at higher densities. We find that the critical Bonnor-Ebert stability criterion is not a good indicator of the boundedness of our cores. We detect the pre-brown dwarf candidate Oph B-11 and find a flux density and mass consistent with previous work. We discuss regional variations in the nature of the cores and find further support for our previous hypothesis of a global evolutionary gradient across the cloud from south-west to north-east, indicating sequential star formation across the region.Peer reviewe
