2,289 research outputs found
Double-resonant fast particle-wave interaction
In future fusion devices fast particles must be well confined in order to
transfer their energy to the background plasma. Magnetohydrodynamic
instabilities like Toroidal Alfv\'en Eigenmodes or core-localized modes such as
Beta Induced Alfv\'en Eigenmodes and Reversed Shear Alfv\'en Eigenmodes, both
driven by fast particles, can lead to significant losses. This is observed in
many ASDEX Upgrade discharges. The present study applies the drift-kinetic
HAGIS code with the aim of understanding the underlying resonance mechanisms,
especially in the presence of multiple modes with different frequencies. Of
particular interest is the resonant interaction of particles simultaneously
with two different modes, referred to as 'double-resonance'. Various mode
overlapping scenarios with different q profiles are considered. It is found
that, depending on the radial mode distance, double-resonance is able to
enhance growth rates as well as mode amplitudes significantly. Surprisingly, no
radial mode overlap is necessary for this effect. Quite the contrary is found:
small radial mode distances can lead to strong nonlinear mode stabilization of
a linearly dominant mode.Comment: 12 pages, 11 figures; Nuclear Fusion 52 (2012
A Method for the Study of Human Factors in Aircraft Operations
A method for the study of human factors in the aviation environment is described. A conceptual framework is provided within which pilot and other human errors in aircraft operations may be studied with the intent of finding out how, and why, they occurred. An information processing model of human behavior serves as the basis for the acquisition and interpretation of information relating to occurrences which involve human error. A systematic method of collecting such data is presented and discussed. The classification of the data is outlined
Spatially resolved information on karst conduit flow from in-cave dye tracing
Artificial tracers are powerful tools for investigating karst systems. Tracers
are commonly injected into sinking streams or dolines, while springs serve
as monitoring sites. The obtained flow and transport parameters represent
mixed information from the vadose, epiphreatic and phreatic zones (that is, the
aquifer remains a black box). Accessible active caves constitute valuable but
underexploited natural laboratories to gain detailed insights into the
hydrologic functioning of the aquifer. Two multi-tracer tests in the
catchment of a major karst spring (Blautopf, Germany) with injections and
monitoring in two associated water caves aimed at obtaining spatially and
temporally resolved information on groundwater flow in different
compartments of the system. Two tracers were injected into the caves to
characterize the hydraulic connections between them and with the spring. Two
injections at the land surface, far from the spring, aimed at resolving the
aquifer's internal drainage structure. Tracer breakthrough curves were
monitored by field fluorimeters in caves and at the spring. Results
demonstrate the dendritic drainage structure of the aquifer. It was possible
to obtain relevant flow and transport parameters for different sections of
this system. The highest mean flow velocities (275 m h−1) were observed
in the near-spring epiphreatic section (open-channel flow), while velocities
in the phreatic zone (pressurized flow) were one order of magnitude lower.
Determined conduit water volumes confirm results of water balances and
hydrograph analyses. In conclusion, experiments and monitoring in caves can
deliver spatially resolved information on karst aquifer heterogeneity and
dynamics that cannot be obtained by traditional investigative methods
Cancer therapy-induced PAFR ligand expression: any role for caspase activity?
No abstract available
The Future of Deer Hunting in New York State: Preliminary Assessment of Three Possible Regulation Changes
Click on the PDF for an Executive Summary and the full report. Visit the HDRU website for a complete listing of HDRU publications at: http://hdru.dnr.cornell.edu
1928 Ruby Yearbook
A digitized copy of the 1928 Ruby, the Ursinus College yearbook.https://digitalcommons.ursinus.edu/ruby/1030/thumbnail.jp
Cooperative Scattering by Cold Atoms
We have studied the interplay between disorder and cooperative scattering for
single scattering limit in the presence of a driving laser. Analytical results
have been derived and we have observed cooperative scattering effects in a
variety of experiments, ranging from thermal atoms in an optical dipole trap,
atoms released from a dark MOT and atoms in a BEC, consistent with our
theoretical predictions.Comment: submitted for special issue of PQE 201
Age-period-cohort analysis of Swiss suicide data, 1881-2000
At the end of the 19th century, male suicide rates in Switzerland were as high as the respective rates in recent decades, whereas female suicide rates were distinctly lower. An age-period-cohort analysis was performed to provide more information about the genderspecific changes over the last century. Suicide mortality has been reported in Switzerland since 1876 when the standardised registration of mortality data began. The analysed data cover the period 1881-2000. The statistical analyses were based on log-linear models and data aggregated by 10-year age-intervals and 10-year periodintervals. The results indicate similar age and period effects in males and females. The estimates representing age-specific risk increase steadily with age, with intermediate plateaus in the 20s and the 50s. The period-specific estimates follow the economic cycles. The birth cohort effects are stronger in males and weaker in females. In the males' estimates, there is a peak in cohorts born around 1840 and a low in cohorts born some 60-100 years later. The estimates increased again in generations born after World War II. In females, the birth cohort estimates are low in cohorts born in the first half of the 19th century and increase until the first half of the 20th century. Birth cohort effects remain an intriguing topic in epidemiology of suicide. A better understanding of birth cohort effects might open new doors to suicide preventio
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