82 research outputs found
On the Testing of Seismicity Models
Recently a likelihood-based methodology has been developed by the
Collaboratory for the Study of Earthquake Predictability (CSEP) with a view to
testing and ranking seismicity models. We analyze this approach from the
standpoint of possible applications to hazard analysis. We arrive at the
conclusion that model testing can be made more efficient by focusing on some
integral characteristics of the seismicity distribution. This is achieved
either in the likelihood framework but with economical and physically
reasonable coarsening of the phase space or by choosing a suitable measure of
closeness between empirical and model seismicity rate in this space.Comment: To appear at Acta Geophysic
Atomic X-ray Spectroscopy of Accreting Black Holes
Current astrophysical research suggests that the most persistently luminous
objects in the Universe are powered by the flow of matter through accretion
disks onto black holes. Accretion disk systems are observed to emit copious
radiation across the electromagnetic spectrum, each energy band providing
access to rather distinct regimes of physical conditions and geometric scale.
X-ray emission probes the innermost regions of the accretion disk, where
relativistic effects prevail. While this has been known for decades, it also
has been acknowledged that inferring physical conditions in the relativistic
regime from the behavior of the X-ray continuum is problematic and not
satisfactorily constraining. With the discovery in the 1990s of iron X-ray
lines bearing signatures of relativistic distortion came the hope that such
emission would more firmly constrain models of disk accretion near black holes,
as well as provide observational criteria by which to test general relativity
in the strong field limit. Here we provide an introduction to this phenomenon.
While the presentation is intended to be primarily tutorial in nature, we aim
also to acquaint the reader with trends in current research. To achieve these
ends, we present the basic applications of general relativity that pertain to
X-ray spectroscopic observations of black hole accretion disk systems, focusing
on the Schwarzschild and Kerr solutions to the Einstein field equations. To
this we add treatments of the fundamental concepts associated with the
theoretical and modeling aspects of accretion disks, as well as relevant topics
from observational and theoretical X-ray spectroscopy.Comment: 63 pages, 21 figures, Einstein Centennial Review Article, Canadian
Journal of Physics, in pres
Linking Distributive and Procedural Justice to Employee Engagement Through Social Exchange: A Field Study in India
Research linking justice perceptions to employee outcomes has referred to social exchange as its central theoretical premise. We tested a conceptual model linking distributive and procedural justice to employee engagement through social exchange mediators, namely, perceived organizational support and psychological contract, among 238 managers and executives from manufacturing and service sector firms in India. Findings suggest that perceived organizational support mediated the relationship between distributive justice and employee engagement, and both perceived organizational support and psychological contract mediated the relationship between procedural justice and employee engagement. Theoretical and practical implications with respect to organizational functions are discussed
Equations for the estimation of strong ground motions from shallow crustal earthquakes using data from Europe and the Middle East : vertical peak ground acceleration and spectral acceleration
This article presents equations for the estimation of vertical strong ground motions caused by shallow crustal earthquakes with magnitudes M w 5 and distance to the surface projection of the fault less than 100km. These equations were derived by weighted regression analysis, used to remove observed magnitude-dependent variance, on a set of 595 strong-motion records recorded in Europe and the Middle East. Coefficients are included to model the effect of local site effects and faulting mechanism on the observed ground motions. The equations include coefficients to model the observed magnitude-dependent decay rate. The main findings of this study are that: short-period ground motions from small and moderate magnitude earthquakes decay faster than the commonly assumed 1/r, the average effect of differing faulting mechanisms is similar to that observed for horizontal motions and is not large and corresponds to factors between 0.7 (normal and odd) and 1.4 (thrust) with respect to strike-slip motions and that the average long-period amplification caused by soft soil deposits is about 2.1 over those on rock sites
Plant strategies of manipulating predatorprey interactions through allelochemicals: Prospects for application in pest control
Atributos físicos, químicos e biológicos de um Latossolo de cerrado em plantio de espécies florestais
Equations for the Estimation of Strong Ground Motions from Shallow Crustal Earthquakes Using Data from Europe and the Middle East: Horizontal Peak Ground Acceleration and Spectral Acceleration
Influences de la sylviculture sur le risque de dégâts biotiques et abiotiques dans les peuplements forestiers
Cytological observations of deletions in pachytene stages of oogenesis and spermatogenesis in the mouse
Using Electro‐Magnetic Induction to Determine Soil Salinity and Sodicity in Turf Root Zones
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