36 research outputs found
The non-ballistic superluminal motion in the plane of the sky-II
The model of non-ballistic jet motion proposed in 2008 provides a simple
explanation to the inward jet motion and bent jet. Recently, evidences of such
a non-radial motion increase rapidly, and more complicated morphologies appear.
On the other hand, the ballistic plus precession model likely holds in majority
samples of jet motion. This paper discusses the relationship between the
ballistic and non-ballistic model of jet motion, which suggests that the
interaction of ejectors with ambient matter can produce knots at different
stages of evolution and hence different separations to the core. And as a jet
precesses, knots produced between the core and the deceleration radius result
in spiral pattern expected by the model of ballistic plus precession; and knots
generated at the deceleration radius display non-radial motion such as bent jet
or oscillation of ridge-line. This paper develops the first non-ballistic model
in four aspects. Firstly, it provides a numerical simulation to the production
of multi-knot for a precessing jet. Secondly, it fits the precession behavior
of multi-knot and interprets the oscillation of ridge lines like S5 1803+784.
Thirdly, it gives an unified interpretation to the bent jet applicable to both
multi-knot and single knot. And fourthly, the problem of very large numbers of
observed outward motions as opposed to the inward ones is addressed in a new
scope.Comment: 9 pages, 6 figures, accepted by MNRA
Leveraging age diversity for organizational performance
The global trend of increasing workplace age diversity has led to growing research attention to the
organizational consequences of age-diverse workforces. Prior research has primarily focused on the
statistical relationship between age diversity and organizational performance without empirically probing
potential mechanisms underlying this relationship. Adopting an intellectual capital perspective, we posit
that age diversity affects organizational performance via human and social capital. Furthermore, we
examine workplace functional diversity and age-inclusive management as two contingent factors shaping
the effects of age diversity on human and social capital. Our hypotheses were tested with a large
manager-report workplace survey data from the Society for Human Resource Management (N 3,888).
Results indicate that age diversity was positively associated wit
Meta-analysis of nature conservation values in Asia & Oceania: Data heterogeneity and benefit transfer issues
We conduct a meta-analysis (MA) of around 100 studies valuing nature conservation in Asia and Oceania. Dividing our dataset into two levels of heterogeneity in terms of good characteristics (endangered species vs. nature conservation more generally) and valuation methods, we show that the degree of regularity and conformity with theory and empirical expectations is higher for the more homogenous dataset of contingent valuation of endangered species. For example, we find that willingness to pay (WTP) for preservation of mammals tends to be higher than other species and that WTP for species preservation increases with income. Increasing the degree of heterogeneity in the valuation data, however, preserves much of the regularity, and the explanatory power of some of our models is in the range of other MA studies of goods typically assumed to be more homogenous (such as water quality). Subjecting our best MA models to a simple test forecasting values for out-of-sample observations, shows median (mean) forecasting errors of 24 (46) percent for endangered species and 46 (89) percent for nature conservation more generally, approaching levels that may be acceptable in benefit transfer for policy use. We recommend that the most prudent MA practice is to control for heterogeneity in regressions and sensitivity analysis, rather than to limit datasets by non-transparent criteria to a level of heterogeneity deemed acceptable to the individual analyst. However, the trade-off will always be present and the issue of acceptable level of heterogeneity in MA is far from settle
Employee well-being attribution and job change intentions: The moderating effect of task idiosyncratic deals
We developed and tested a research model in which employee well-being human resource (HR) attribution differentially influences the intention to change jobs across organizations (i.e., external job change intention) versus that within the same organization (i.e., internal job change intention). Furthermore, we posited that task idiosyncratic deals (I-deals) moderated the relationships between employee well-being HR attribution and external and internal job change intentions. Results indicated that employee well-being HR attribution was negatively related to external job change intention, but positively related to internal job change intention. Further, task I-deals significantly moderated the relationships between employee well-being HR attribution and external and internal job change intention. Specifically, employee well-being HR attribution played a less important role in reducing external job change intention when task I-deals were high rather than low. On the other hand, high task I-deals significantly strengthened the positive relationship between employee well-being HR attribution and internal job change intention. Our study extends the careers literature by differentiating the impact of employee well-being HR attribution on job change intentions within an organization compared with that across organizations and the important role of supervisors in enhancing or mitigating these effects