2,458 research outputs found
I\u27m Thankful Every Day I Did It : An Exploration of Belonging for Commuter Students in Historically White Sororities and Fraternities at Primarily Commuter Public Institutions
Membership in historically White sororities and fraternities (HWSF) has been connected with sense of belonging (Cohen et al., 2017; McCreary & Schutts, 2015). The experience of commuter students in sororities and fraternities, however, has been largely overlooked, including an understanding of what belonging consists of as members. This phenomenological study sought to close that gap by exploring how commuter students in HWSF experienced belonging at primarily commuter public institutions through interviews with alumni who lived that experience. Three themes emerged from the data: personal connections, feeling welcomed and accepted, and transformation of the college experience
A Generalized Error Distribution Copula-based method for portfolios risk assessment
In this paper, we deal with the evaluation of Conditional Value-at-Risk in the framework of portfolio theory by using a modified Gaussian Copula – where the modification is obtained by introducing the Generalized Correlation Coefficient – and by assuming a Generalized Error Distribution with properly estimated shape parameter for the returns of the considered risky assets. In so doing, we add to the connection between standard Copula theory and financial risk assessment. A comparison analysis of our findings with those obtainable through a standard Gaussian Copula-based procedure in a set of real data is also presented
A Nonparametric Approach for Testing Long Memory in Stock Returns’ Higher Moments
In this paper, by considering a model-based approach for conditional moment estimation, a nonparametric test was performed to study the long-memory property of higher moments. We considered the daily returns of the stocks included in the S&P500 index in the last ten years (for the period running from the 1st of January 2011 to the 1st of January 2021). We found that mean and skewness were characterized by short memory, while variance and shape had long memory. These results have deep implications in terms of asset allocation, option pricing and market efficiency evaluation
A bootstrap-based approach for sample size calculation when traditional estimations are not possible
Dynamical effects of self-generated magnetic fields in cosmic ray modified shocks
Recent observations of greatly amplified magnetic fields () around supernova shocks are consistent with the predictions of the
non-linear theory of particle acceleration (NLT), if the field is generated
upstream of the shock by cosmic ray induced streaming instability. The high
acceleration efficiencies and large shock modifications predicted by NLT need
however to be mitigated to confront observations, and this is usually assumed
to be accomplished by some form of turbulent heating. We show here that
magnetic fields with the strength inferred from observations have an important
dynamical role on the shock, and imply a shock modification substantially
reduced with respect to the naive unmagnetized case. The effect appears as soon
as the pressure in the turbulent magnetic field becomes comparable with the
pressure of the thermal gas. The relative importance of this unavoidable effect
and of the poorly known turbulent heating is assessed. More specifically we
conclude that even in the cases in which turbulent heating may be of some
importance, the dynamical reaction of the field cannot be neglected, as instead
is usually done in most current calculations.Comment: 4 pages, 1 figure, accepted for publication in ApJ Letter
Thermal fluctuations on the freeze-out surface of heavy-ion collisions and their impact on particle correlations
Particle momentum distributions originating from a quark-gluon plasma asproduced in high-energy nuclear collisions can be influenced by thermalfluctuations in fluid dynamic fields. We study this effect by generalizing thecommonly used kinetic freeze-out prescription by allowing for smallfluctuations around an average in fluid velocity, chemical potentials andtemperature. This leads to the appearance of specific two-body momentumcorrelations. Combining a blast-wave parametrization of the kinetic freeze-outsurface with the thermal correlation functions of an ideal resonance gas, weperform an exploratory study of angular net-charge correlations induced bythermal fluctuations around vanishing chemical potential. We note a diffusionof the near-side peak around induced by variances ofdifferent chemical potentials, which could be investigated experimentally.<br
Pick-up ion dynamics at the structured quasi-perpendicular shock
We study the pickup ion dynamics and mechanism of multiple reflection and
acceleration at the structured quasi-perpendicular supercritical shock. The
motion of the pickup ions in the shock is studied analytically and numerically
using the test particle analysis in the model shock front. The analysis shows
that slow pickup ions may be accelerated at the shock ramp to high energies.
The maximum ion energy is determined by the fine structure of the
electro-magnetic field at the shock ramp and decreases when the angle between
magnetic field and shock normal decreases. Evolution of pickup ion distribution
across the nearly-perpendicular shock and pickup ion spectrum is also studied
by direct numerical analysis.Comment: LaTeX (elsart.cls), packages: times,amsmath,amssymb; 15 pages + 13
figures (GIF). To appear in Planetary and Space Science
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