The Orbital Light Curve of Aquila X-1

We obtained R- and I-band CCD photometry of the soft X-ray transient/neutron- star binary Aql X-1 in 1998 June while it was at quiescence. We find that its light curve is dominated by ellipsoidal variations, although the ellipsoidal variations are severely distorted and have unequal maxima. After we correct for the contaminating flux from a field star located only 0.46" away, the peak-to-peak amplitude of the modulation is ~0.25 mag in the R band, which requires the orbital inclination to be greater than 36 degrees. The orbital period we measure is consistent with the 18.95 h period measured by Chevalier & Ilovaisky (1998). During its outbursts the light curve of Aql X-1 becomes single humped. The outburst light curve observed by Garcia et al. (1999) agrees in phase with our quiescent light curve. We show that the single humped variation is caused by a ``reflection effect,'' that is, by heating of the side of the secondary star facing towards the neutron star.Comment: 18 manuscript pages, 7 figures; accepted by A

Reference Transcriptome for a Facultatively Eusocial Bee, Megalopta genalis

This article analyses gendering processes in two distinct models of work organization. It is a widespread belief that, compared to hierarchical (Tayloristic) organizations, team-based work offers opportunities for a high quality of working life to a broader range of employees, both men and women. Our research, however, suggests that gender inequality is (re)produced in both settings and results from the so-called gender subtext. The gender subtext is the set of often concealed power-based processes (re)producing gender distinction in social practices through organizational and individual arrangements. We draw a comparison between the gender subtext of Tayloristic and team-based work organizations through a theoretical analysis, illustrated by empirical data concerning the functioning of the gender subtext in organizations in the Dutch banking sector. Taylorism and team-based work differ in their conceptualization of organization and job design, but, when it comes to the gender subtext, it is six of one and half a dozen of the other. We argue that in both approaches a gender subtext contributes to the emergence of different but gendered notions of the ‘disembodied worker’. In both cases the notion of the abstract worker is implicitly loaded with masculine connotations. This gender bias is supported by two factors influencing the gendering of jobs: the gender connotations of care responsibilities and of qualification profiles. These implicit connotations produce and reinforce unequal opportunities for men and women to get highly qualified or management jobs. Our research, therefore, questions the self-evidence of stating that team-based work will offer opportunities for a higher quality of working life for women

The Relationship Between Social Vulnerability and COVID-19 Incidence Among Louisiana Census Tracts

Objective: To examine the association between the Centers for Disease Control and Prevention (CDC)\u27s Social Vulnerability Index (SVI) and COVID-19 incidence among Louisiana census tracts. Methods: An ecological study comparing the CDC SVI and census tract-level COVID-19 case counts was conducted. Choropleth maps were used to identify census tracts with high levels of both social vulnerability and COVID-19 incidence. Negative binomial regression with random intercepts was used to compare the relationship between overall CDC SVI percentile and its four sub-themes and COVID-19 incidence, adjusting for population density. Results: In a crude stratified analysis, all four CDC SVI sub-themes were significantly associated with COVID-19 incidence. Census tracts with higher levels of social vulnerability were associated with higher COVID-19 incidence after adjusting for population density (adjusted RR: 1.52, 95% CI: 1.41-1.65). Conclusions: The results of this study indicate that increased social vulnerability is linked with COVID-19 incidence. Additional resources should be allocated to areas of increased social disadvantage to reduce the incidence of COVID-19 in vulnerable populations

Venous bullet embolism and subsequent endovascular retrieval – A case report and review of the literature

AbstractINTRODUCTIONVascular bullet embolism is a rare phenomenon with fewer than 200 cases reported in the literature.PRESENTATION OF CASEA 22 year-old male presented with a gunshot wound to the right lower quadrant. Imaging demonstrated a bullet lodged in his left lower quadrant. Upon operative exploration, a single hole was found in the right external iliac vein without injury into the left lower quadrant. The bullet was found to have migrated intravascularly from the right external to the left common iliac vein, and was subsequently removed endovascularly.DISCUSSIONBullet embolism occurs infrequently, with arterial more common than venous. Arterial embolization usually requires emergency operative intervention due to ischemia. While venous embolization is often asymptomatic, removal of the bullet is recommended to avoid delayed complications when possible.CONCLUSIONVenous bullet emboli should be removed endovascularly whenever technically possible

First-mover advantages from pioneering new markets: A survey of empirical evidence

Market pioneers can develop first-mover advantages that span decades. The most general first-mover advantage that helps explain higher pioneer market share levels is a broad product line or brand proliferation. In markets for experience goods, pioneers tend to shape consumer tastes and preferences in favor of the pioneering brand. While the preliminary results vary by industry, they indicate that market pioneers do not tend to perish more often than later entrants. Accounting profits for market pioneers generally are lower in the first four years of operation, but higher thereafter. Overall, market pioneers follow innovative strategies that have high initial costs and risks, but yield high potential returns.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43581/1/11151_2005_Article_BF01024216.pd