60 research outputs found
The Highly Ionized Circumgalactic Medium is Kinematically Uniform around Galaxies
Large scale structure and cosmolog
Understanding the strong intervening O VI absorber at z_abs 0.93 towards PG1206+459
Large scale structure and cosmolog
Disparate MgII Absorption Statistics towards Quasars and Gamma-Ray Bursts : A Possible Explanation
We examine the recent report by Prochter et al. (2006) that gamma-ray burst
(GRB) sight lines have a much higher incidence of strong MgII absorption than
quasar sight lines. We propose that the discrepancy is due to the different
beam sizes of GRBs and quasars, and that the intervening MgII systems are
clumpy with the dense part of each cloudlet of a similar size as the quasars,
i.e. < 10^16 cm, but bigger than GRBs. We also discuss observational
predictions of our proposed model. Most notably, in some cases the intervening
MgII absorbers in GRB spectra should be seen varying, and quasars with smaller
sizes should show an increased rate of strong MgII absorbers. In fact, our
prediction of variable MgII lines in the GRB spectra has been now confirmed by
Hao et al. (2007), who observed intervening FeII and MgII lines at z=1.48 to be
strongly variable in the multi-epoch spectra of z=4.05 GRB060206.Comment: 12 pages, 2 figures; substantially revised model calculation;
accepted for publication in Astrophysics & Space Science as a Lette
Representational predicaments for employees: Their impact on perceptions of supervisors\u27 individualized consideration and on employee job satisfaction
A representational predicament for a subordinate vis-à-vis his or her immediate superior involves perceptual incongruence with the superior about the subordinate\u27s work or work context, with unfavourable implications for the employee. An instrument to measure the incidence of two types of representational predicament, being neglected and negative slanting, was developed and then validated through an initial survey of 327 employees. A subsequent substantive survey with a fresh sample of 330 employees largely supported a conceptual model linking being neglected and negative slanting to perceptions of low individualized consideration by superiors and to low overall job satisfaction. The respondents in both surveys were all Hong Kong Chinese. Two case examples drawn from qualitative interviews illustrate and support the conceptual model. Based on the research findings, we recommend some practical exercises to use in training interventions with leaders and subordinates. © 2013 Copyright Taylor and Francis Group, LLC
Performance configurations over time: implications for growth- and profit-oriented strategies
Strategic entrepreneurship can be described as simultaneous opportunity seeking and advantage seeking. Younger firms are generally more flexible and therefore enjoy 'discovery advantages', whereas established firms tend to be resource rich and more experienced and consequently enjoy 'exploitation advantages'. The resulting evolution of the two important performance dimensions 'growth' and 'profitability' by firm age is not well understood. In this paper we integrate several theoretical arguments concerning profit-growth relationships to develop a dynamic model of firm development which suggests different development pathways for young firms. This leads to several unidirectional, competing hypotheses that we examine by studying the profitability-growth configurations of approximately 3,500 small firms and how these configurations evolve over time. We find that for both young and old firms, a focus on achieving above-average profitability and then striving for growth is a more likely path towards achieving sustained above-average performance than is first pursuing strong growth in the hope of building profitability later. In line with our hypothesis we find that younger firms are over-represented as 'Stars' (high on both growth and profitability) and under-represented as 'Poor' (low on both growth and profitability). However, young firms in the 'Star' category are also less likely than their older counterparts to maintain that position. Furthermore, our results indicate that young firms are over-represented not only among 'Stars', but also among growth-orientated firms regardless of the level of profitability. The findings strongly caution against the blind pursuit of growth for young firms, in favor of a thoughtful analysis of how both growth and profitability might be developed by firms. The results also question whether simultaneous high performance in terms of growth and profitability among young firms usually reflects a successful entrepreneurial strategy. The results can also be interpreted as luck on the part of a sub-group of young firms who indiscriminately pursue growth opportunities with varying profit prospects, and in many cases the high growth-profit performance will be short lived
A low-frequency chip-scale optomechanical oscillator with 58 kHz mechanical stiffening and more than 100th-order stable harmonics
10.1038/s41598-017-04882-4Scientific Reports71488
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