14,403 research outputs found
Very High Energy Gamma Rays from Supernova Remnants and Constraints on the Galactic Interstellar Radiation Field
The large-scale Galactic interstellar radiation field (ISRF) is the result of
stellar emission and dust re-processing of starlight. Where the energy density
of the ISRF is high (e.g., the Galactic Centre), the dominant gamma-ray
emission in individual supernova remnants (SNRs), such as G0.9+0.1, may come
from inverse Compton (IC) scattering of the ISRF. Several models of the ISRF
exist. The most recent one, which has been calculated by us, predicts a
significantly higher ISRF than the well-used model of Mathis, Mezger, and
Panagia. However,comparison with data is limited to local observations. Based
on our current estimate of the ISRF we predict the gamma-ray emission in the
SNRs G0.9+0.1 and RXJ1713, and pair-production absorption features above 20 TeV
in the spectra of G0.9+0.1, J1713-381, and J1634-472. We discuss how GLAST,
along with current and future very high energy instruments, may be able to
provide upper bounds on the large-scale ISRF.Comment: To appear in the proceedings of the 1st GLAST Symposiu
Leading and Managing Those Working and Living in Captive Environments
I magine you are the warden of a prison or the administrator of a jail, you enter the facility, and the heavy metal door clangs shut behind you. A riot breaks out and several members of your staff are taken hostage. Fires are set in various locations. The rioting inmates, members of a gang, attack other inmates who want no part in the rebellion and are only concerned for their safety. The decisions you as a leader make are literally matters of life or death, not only for yourself, but also for your staff and those incarcerated. The dynamics of power and guarding against potential corruption are also a constant concern. The leader of an incarceration facility must account for and respond to public opinion and political demands, as well as the individual needs and group dynamics of corrections officers and inmates.
Some of the desired outcomes for leaders in a confinement setting are a reduction in recidivism, security of the facility, prevention of escape, and efforts at rehabilitation. While some would argue that depending upon the reason for incarceration, the inmates do not deserve much more consideration than would an animal in a zoo, others-leaders-in this situation strive for much more. Accomplished leaders in a confinement setting seek to develop a culture that creates and sustains the psychological health and well-being of the corrections officers and provides inmates opportunities to develop skills and their potential. After all, they are in the people business. Such an approach would conceivably result in an institution that functions based on the strengths of the corrections officers and inmates, thereby allowing them the greatest opportunity for self-development, physical and psychological security, and indirectly decreased chances of recidivism.
This chapter discusses the contexts of confinement, the psychology of corrections officers and inmates, and the forces at work on a leader and the population being led
Leading and Managing Those Working and Living in Captive Environments
I magine you are the warden of a prison or the administrator of a jail, you enter the facility, and the heavy metal door clangs shut behind you. A riot breaks out and several members of your staff are taken hostage. Fires are set in various locations. The rioting inmates, members of a gang, attack other inmates who want no part in the rebellion and are only concerned for their safety. The decisions you as a leader make are literally matters of life or death, not only for yourself, but also for your staff and those incarcerated. The dynamics of power and guarding against potential corruption are also a constant concern. The leader of an incarceration facility must account for and respond to public opinion and political demands, as well as the individual needs and group dynamics of corrections officers and inmates.
Some of the desired outcomes for leaders in a confinement setting are a reduction in recidivism, security of the facility, prevention of escape, and efforts at rehabilitation. While some would argue that depending upon the reason for incarceration, the inmates do not deserve much more consideration than would an animal in a zoo, others-leaders-in this situation strive for much more. Accomplished leaders in a confinement setting seek to develop a culture that creates and sustains the psychological health and well-being of the corrections officers and provides inmates opportunities to develop skills and their potential. After all, they are in the people business. Such an approach would conceivably result in an institution that functions based on the strengths of the corrections officers and inmates, thereby allowing them the greatest opportunity for self-development, physical and psychological security, and indirectly decreased chances of recidivism.
This chapter discusses the contexts of confinement, the psychology of corrections officers and inmates, and the forces at work on a leader and the population being led
Fermi-LAT Observations of High- and Intermediate-Velocity Clouds: Tracing Cosmic Rays in the Halo of the Milky Way
It is widely accepted that cosmic rays (CRs) up to at least PeV energies are
Galactic in origin. Accelerated particles are injected into the interstellar
medium where they propagate to the farthest reaches of the Milky Way, including
a surrounding halo. The composition of CRs coming to the solar system can be
measured directly and has been used to infer the details of CR propagation that
are extrapolated to the whole Galaxy. In contrast, indirect methods, such as
observations of gamma-ray emission from CR interactions with interstellar gas,
have been employed to directly probe the CR densities in distant locations
throughout the Galactic plane. In this article we use 73 months of data from
the Fermi Large Area Telescope in the energy range between 300 MeV and 10 GeV
to search for gamma-ray emission produced by CR interactions in several high-
and intermediate-velocity clouds located at up to ~ 7 kpc above the Galactic
plane. We achieve the first detection of intermediate-velocity clouds in gamma
rays and set upper limits on the emission from the remaining targets, thereby
tracing the distribution of CR nuclei in the halo for the first time. We find
that the gamma-ray emissivity per H atom decreases with increasing distance
from the plane at 97.5% confidence level. This corroborates the notion that CRs
at the relevant energies originate in the Galactic disk. The emissivity of the
upper intermediate-velocity Arch hints at a 50% decline of CR densities within
2 kpc from the plane. We compare our results to predictions of CR propagation
models.Comment: Accepted for publication in the Astrophysical Journa
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