1,070 research outputs found
Virial mass in DGP brane cosmology
We study the virial mass discrepancy in the context of a DPG brane-world
scenario and show that such a framework can offer viable explanations to
account for the mass discrepancy problem. This is done by defining a
geometrical mass that we prove to be proportional to the virial
mass. Estimating using observational data, we show that it
behaves linearly with and has a value of the order of , pointing
to a possible resolution of the virial mass discrepancy. We also obtain the
radial velocity dispersion of galaxy clusters and show that it is compatible
with the radial velocity dispersion profile of such clusters. This velocity
dispersion profile can be used to differentiate various models predicting the
virial mass.Comment: 12 pages, 1 figure, to appear in CQ
The US in Uterus: A Collaborative Autoethnography of Psychologists Advocating for Reproductive Justice
In light of the recent Supreme Court decision to overturn Roe v. Wade, millions of people with uteruses have been forced to navigate precarious access to reproductive care. Although health service psychologists have an ethical responsibility to engage in reproductive justice advocacy, training programs often do not adequately address sexual and reproductive health. Therefore, we sought to better understand how health service psychologists’ personal and professional experiences influence each other and explore the ways in which we as reproductive beings and advocates sustain ourselves amidst tremendous sociopolitical uncertainty. In order to do so, we employed a feminist collaborative autoethnography approach grounded in critical theory. Attending to intersectional identities that help shape diverse expectations and experiences, two early career psychologists and four trainees uncovered 12 domains: barriers in academia; reproductive (dis)empowerment; relational connection; power(lessness) associated with social locations; internalization of sex-negative messages; the influence of sociopolitical climate; burdens related to reproductive rights; evaluations of reproductive justice efforts; component of professional identity; expectations from family and community; overwhelming and exhausting advocacy; and fears of inadequacy. We conclude with limitations and implications for the continued promotion of advocacy through practice and training within and beyond the field of psychology
Spectral Evidence for Emergent Order in BaNaFeAs
We report an angle-resolved photoemission spectroscopy study of the
iron-based superconductor family, BaNaFeAs. This system
harbors the recently discovered double-Q magnetic order appearing in a
reentrant C phase deep within the underdoped regime of the phase diagram
that is otherwise dominated by the coupled nematic phase and collinear
antiferromagnetic order. From a detailed temperature-dependence study, we
identify the electronic response to the nematic phase in an orbital-dependent
band shift that strictly follows the rotational symmetry of the lattice and
disappears when the system restores C symmetry in the low temperature
phase. In addition, we report the observation of a distinct electronic
reconstruction that cannot be explained by the known electronic orders in the
system
Microscopic Theory of Heterogeneity and Non-Exponential Relaxations in Supercooled Liquids
Recent experiments and computer simulations show that supercooled liquids
around the glass transition temperature are "dynamically heterogeneous" [1].
Such heterogeneity is expected from the random first order transition theory of
the glass transition. Using a microscopic approach based on this theory, we
derive a relation between the departure from Debye relaxation as characterized
by the value of a stretched exponential response function , and the fragility of the liquid. The
value is also predicted to depend on temperature and to vanish as the ideal
glass transition is approached at the Kauzmann temperature.Comment: 4 pages including 3 eps figure
Anomalous relaxation and self-organization in non-equilibrium processes
We study thermal relaxation in ordered arrays of coupled nonlinear elements
with external driving. We find, that our model exhibits dynamic
self-organization manifested in a universal stretched-exponential form of
relaxation. We identify two types of self-organization, cooperative and
anti-cooperative, which lead to fast and slow relaxation, respectively. We give
a qualitative explanation for the behavior of the stretched exponent in
different parameter ranges. We emphasize that this is a system exhibiting
stretched-exponential relaxation without explicit disorder or frustration.Comment: submitted to PR
Onset of rigidty in glasses: from random to self-organized networks
We review in this paper the signatures of a new elastic phase that is found
in glasses with selected compositions. It is shown that in contrast with random
networks, where rigidity percolates at a single threshold, networks that are
able to self-organize to avoid stress will remain in an almost stress- free
state during a compositional interval, an intermediate phase, that is bounded
by a flexible phase and a stressed rigid phase. We report the experimental
signatures and describe the theoretical efforts that have been accomplished to
characterize the intermediate phase. We illustrate one of the methods used in
more detail with the example of Group III chalcogenides and finally suggest
further possible experimental signatures of self-organization.Comment: 27 pages, 6 figures, Proceedings of the Conference on Non-Crystalline
Materials 10, to appear in Journal of Non-Crystalline Solid
The role of ethylene and 1-MCP in early-season sweet cherry ‘Burlat’ storage life
Sweet cherries (Prunus avium L.) are highly appreciated because of their bioactive compound content and attractive organoleptic characteristics; however, they are very perishable. The aim of this work was to investigate whether ethylene and its antagonist 1-MCP affect the postharvest quality of an early-season sweet cherry cultivar, allowing storage life extension. ‘Burlat’ sweet cherries were subjected to three treatments at 1 °C for one month: i) control (air); ii) continuous ethylene supplementation (10 μL L−1); and iii) 1-Methylcyclopropene (1-MCP; 1 μL L−1 for 24 h) followed by air. The incidence of postharvest physiological disorders, the evolution of physical and functional quality traits, and fruit senescence were evaluated at 0, 7, 14, 21, and 30 days. Results showed that sweet cherries were sensitive to both ethylene and 1-MCP treatments. Continuous ethylene exposure reduced abscisic acid accumulation, resulting in higher weight and firmness loss. Moreover, ethylene application decreased titratable acidity through storage, indicating an effect on sweet cherry senescence. No significant differences among treatments were found for soluble solids content and individual sugars. Conversely, 1-MCP preserved firmness during the first 7 days of storage, while reduced the incidence of physiological disorders at the end of storage life. Furthermore, 1-MCP delayed the accumulation of cyanidin-3-O-glucoside for 7 days compared to control and ethylene treated cherries. Taken together these results highlight the potential use of 1-MCP to extend the postharevst life of early season sweet cherry fruit
Lattice dynamics and correlated atomic motion from the atomic pair distribution function
The mean-square relative displacements (MSRD) of atomic pair motions in
crystals are studied as a function of pair distance and temperature using the
atomic pair distribution function (PDF). The effects of the lattice vibrations
on the PDF peak widths are modelled using both a multi-parameter Born
von-Karman (BvK) force model and a single-parameter Debye model. These results
are compared to experimentally determined PDFs. We find that the near-neighbor
atomic motions are strongly correlated, and that the extent of this correlation
depends both on the interatomic interactions and crystal structure. These
results suggest that proper account of the lattice vibrational effects on the
PDF peak width is important in extracting information on static disorder in a
disordered system such as an alloy. Good agreement is obtained between the BvK
model calculations of PDF peak widths and the experimentally determined peak
widths. The Debye model successfully explains the average, though not detailed,
natures of the MSRD of atomic pair motion with just one parameter. Also the
temperature dependence of the Debye model largely agrees with the BvK model
predictions. Therefore, the Debye model provides a simple description of the
effects of lattice vibrations on the PDF peak widths.Comment: 9 pages, 11 figure
Spinning Loop Black Holes
In this paper we construct four Kerr-like spacetimes starting from the loop
black hole Schwarzschild solutions (LBH) and applying the Newman-Janis
transformation. In previous papers the Schwarzschild LBH was obtained replacing
the Ashtekar connection with holonomies on a particular graph in a
minisuperspace approximation which describes the black hole interior. Starting
from this solution, we use a Newman-Janis transformation and we specialize to
two different and natural complexifications inspired from the complexifications
of the Schwarzschild and Reissner-Nordstrom metrics. We show explicitly that
the space-times obtained in this way are singularity free and thus there are no
naked singularities. We show that the transformation move, if any, the
causality violating regions of the Kerr metric far from r=0. We study the
space-time structure with particular attention to the horizons shape. We
conclude the paper with a discussion on a regular Reissner-Nordstrom black hole
derived from the Schwarzschild LBH and then applying again the Newmann-Janis
transformation.Comment: 18 pages, 18 figure
Toward a wiki guide for obstetrics and gynecology trainees in Ireland.
BACKGROUND: The present paper describes the implementation of a novel, web-based, comprehensive national information hub for trainees in obstetrics and gynecology in Ireland. This was a unique development in the context of an entire medical specialty and was aligned with the communication strategy of the governing professional body. To date, trainee doctors working in Ireland undergo an incoherent and inconsistent new-staff induction and handover. In the healthcare setting, staff integration can have a major impact on the quality of patient care.
METHODS: A free wiki software platform (PBworks) was used for the website, and freely available software (Google Analytics) was used to determine user interaction and level of engagement.
RESULTS: In the first year, 442 user visits were recorded. The average duration of site visits was 4minutes 39seconds, which compared favorably with the 4-minute duration for visits to Wikipedia.
CONCLUSION: The project was successful as a proof concept and in practice. Other medical faculties have expressed an interest in adopting the concept and developing it for their trainees. The concept is widely applicable to other countries, with the negligible cost relevant to resource-poor areas
- …