44,523 research outputs found
COMPTEL solar flare measurements
We review some of the highlights of the COMPTEL measurements of solar flares. These include images of the Sun in γ rays and neutrons. One of the important features of the COMPTEL instrument is its capability to measure weak fluxes of γ rays and neutrons in the extended phase of flares. These data complement the spectra taken with the COMPTEL burst spectrometer and the telescope during the impulsive phase of flares. We focus our attention on some of these general capabilities of the instrument and the latest results of two long‐duration γ‐ray flares, i.e., 11 and 15 June 199
Infrared emission from kilonovae: the case of the nearby short hard burst GRB 160821B
We present constraints on Ks-band emission from one of the nearest short hard
gamma-ray bursts, GRB 160821B, at z=0.16, at three epochs. We detect a reddened
relativistic afterglow from the jetted emission in the first epoch but do not
detect any excess kilonova emission in the second two epochs. We compare upper
limits obtained with Keck I/MOSFIRE to multi-dimensional radiative transfer
models of kilonovae, that employ composition-dependent nuclear heating and LTE
opacities of heavy elements. We discuss eight models that combine toroidal
dynamical ejecta and two types of wind and one model with dynamical ejecta
only. We also discuss simple, empirical scaling laws of predicted emission as a
function of ejecta mass and ejecta velocity. Our limits for GRB 160821B
constrain the ejecta mass to be lower than 0.03 Msun for velocities greater
than 0.1c. At the distance sensitivity range of advanced LIGO, similar
ground-based observations would be sufficiently sensitive to the full range of
predicted model emission including models with only dynamical ejecta. The color
evolution of these models shows that I-K color spans 7--16 mag, which suggests
that even relatively shallow infrared searches for kilonovae could be as
constraining as optical searches.Comment: Accepted for Publication in Astrophysical Journal Letter
Entrepreneurial Innovation
This paper constructs an equilibrium model of entrepreneurial innovation where individuals differ in their attitude toward uncertainty.Unlike previous models of innovation, the firm-formation process is endogenous.An entrepreneur, who owns residual profits, utilizes an uncertain technology and hires a worker who may only be partially isolated from uncertainty.While the available production technologies are exogenously specified, the technologies that operate in equilibrium are endogenous, depending on both the entrepreneur's prior beliefs about the profitability of the technology, as well as the worker's willingness to work with the uncertain technology.The general equilibrium setting allows us to explore the impact of innovation on the nature of the firm. The relationship between technological uncertainty and the nature of the firm is able to explain the commonly observed S-shaped diffusion profile.As uncertainty falls, firms evolve from being entrepreneurial to corporate, finally becoming bureaucratic.entrepreneurship;uncertainty;innovation
Critical superfluid velocity in a trapped dipolar gas
We investigate the superfluid properties of a dipolar Bose-Einstein
condensate (BEC) in a fully three-dimensional trap. Specifically, we calculate
a superfluid critical velocity for this system by applying the Landau criterion
to its discrete quasiparticle spectrum. We test this critical velocity by
direct numerical simulation of condensate depletion as a blue-detuned laser
moves through the condensate. In both cases, the presence of the roton in the
spectrum serves to lower the critical velocity beyond a critical particle
number. Since the shape of the dispersion, and hence the roton minimum, is
tunable as a function of particle number, we thereby propose an experiment that
can simultaneously measure the Landau critical velocity of a dipolar BEC and
demonstrate the presence of the roton in this system.Comment: 5 pages, 4 figures, version accepted to PR
Measuring Beliefs Supportive of Environmental Action and Inaction: A Reinterpretation of the Awareness of Consequences Scale
The Value-Belief-Norm model assumes that egoistic, social-altruistic and biospheric value orientations causally influence how people cognitively structure beliefs regarding adverse environmental consequences. Empirical studies have administered the Awareness of Consequences (AC) scale to differentiate between these three orientations. We report an analysis which challenges previous work in the field. Evidence is presented that indicates the AC scale should be reinterpreted as a measure of beliefs supporting environmental action and beliefs supporting environmental inaction. The beliefs supporting environmental action appear to be differentiable according to beliefs in the positive consequences from environmental protection and the seriousness of environment harm. This has major implications for the Value-Belief-Norm model and its application.Environmental attitudes; awareness of consequences scale; environmental beliefs; value orientations; environmental scales; egoistic; altruistic; biospheric; value-belief-norm model
Autonomy and autonomy disturbances in self-development and psychopathology: research on motivation, attachment, and clinical process
Self-determination theory (SDT) maintains that the adequate support and satisfaction of individuals' psychological needs for autonomy, competence, and relatedness promotes the gradual unfolding of individuals' integrative tendencies, as manifested through intrinsic motivation, internalization, identity development, and integrative emotion regulation. At the same time, the thwarting of these same psychological needs and the resultant need frustration is presumed to evoke or amplify a variety of psychopathologies, many of which involve autonomy disturbances. We begin by defining what autonomy involves and how socializing agents, particularly parents, can provide a nurturing (i.e., need-supportive) environment, and we review research within the SDT literature that has shed light on various integrative tendencies and how caregivers facilitate them. In the second part of this chapter, we detail how many forms of psychopathology involve autonomy disturbances and are associated with a history of psychological need thwarting. We especially focus on internally controlling regulation in internalizing disorders; impairments of internalization in conduct disorders and antisocial behavior; and fragmented self-functioning in borderline and dissociative disorders. The role of autonomy support as an ameliorative factor in treatment settings is then discussed among other translational issues. Finally we highlight some implications of recognizing the important role of basic psychological needs for both growth-related and pathology-related processes
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