15,049 research outputs found
Effects of street traffic noise in the night
The relationship between automobile traffic noise and the degree of disturbance experience experienced at night was explored through a random sample survey of 1600 individuals in rural and urban areas. The data obtained were used to establish threshold values
Josephson Coupling through a Quantum Dot
We derive, via fourth order perturbation theory, an expression for the
Josephson current through a gated interacting quantum dot. We analyze our
expression for two different models of the superconductor-dot-superconductor
(SDS) system. When the matrix elements connecting dot and leads are featureless
constants, we compute the Josephson coupling J_c as a function of the gate
voltage and Coulomb interaction. In the diffusive dot limit, we compute the
probability distribution P(J_c) of Josephson couplings. In both cases, pi
junction behavior (J_c < 0) is possible, and is not simply dependent on the
parity of the dot occupancy.Comment: 9 pages; 3 encapsulated PostScript figure
Probabilistic Strain Energy Life Assessment Model
AbstractUnder the âsafe-lifeâ methodology used by the United States Navy the service life of aircraft fleet are determined by monitoring the aircraft's usage and estimating the respective fatigue damage. The calculated fatigue life expenditure representing cumulative damage is then used to determine if it is possible for an aircraft or a fleet of aircrafts to reach the point of crack initiation and whether or not it should be retired. This research focuses on the development and initial application of a probabilistic strain-energy model to augment the empirical-based fatigue life expended approach. Experimental fatigue data obtained in this research is used to determine the relation between the number of cycles-to-failure and the cumulative total strain energy. A Bayesian framework for regression, including consideration of the model error is used to develop a probabilistic model of life that includes parameter uncertainties due to the limitation and scatter observed in the experimental data
ZOBOV: a parameter-free void-finding algorithm
ZOBOV (ZOnes Bordering On Voidness) is an algorithm that finds density
depressions in a set of points, without any free parameters, or assumptions
about shape. It uses the Voronoi tessellation to estimate densities, which it
uses to find both voids and subvoids. It also measures probabilities that each
void or subvoid arises from Poisson fluctuations. This paper describes the
ZOBOV algorithm, and the results from its application to the dark-matter
particles in a region of the Millennium Simulation. Additionally, the paper
points out an interesting high-density peak in the probability distribution of
dark-matter particle densities.Comment: 10 pages, 8 figures, MNRAS, accepted. Added explanatory figures, and
better edge-detection methods. ZOBOV code available at
http://www.ifa.hawaii.edu/~neyrinck/vobo
Constrained Local UniversE Simulations: A Local Group Factory
Near field cosmology is practiced by studying the Local Group (LG) and its
neighbourhood. The present paper describes a framework for simulating the near
field on the computer. Assuming the LCDM model as a prior and applying the
Bayesian tools of the Wiener filter (WF) and constrained realizations of
Gaussian fields to the Cosmicflows-2 (CF2) survey of peculiar velocities,
constrained simulations of our cosmic environment are performed. The aim of
these simulations is to reproduce the LG and its local environment. Our main
result is that the LG is likely a robust outcome of the LCDM scenario when
subjected to the constraint derived from CF2 data, emerging in an environment
akin to the observed one. Three levels of criteria are used to define the
simulated LGs. At the base level, pairs of halos must obey specific isolation,
mass and separation criteria. At the second level the orbital angular momentum
and energy are constrained and on the third one the phase of the orbit is
constrained. Out of the 300 constrained simulations 146 LGs obey the first set
of criteria, 51 the second and 6 the third. The robustness of our LG factory
enables the construction of a large ensemble of simulated LGs. Suitable
candidates for high resolution hydrodynamical simulations of the LG can be
drawn from this ensemble, which can be used to perform comprehensive studies of
the formation of the LGComment: 13 pages, accepted for publication in MNRA
Feminist Perspectives on Disaster, Pandemics, and Intimate Partner Violence
The COVID-19 pandemic brought international awareness to the likelihood of increased abuse of those in abusive intimate partner relationships because of the forced confinement with their abusers (Bettinger-Lopez and Bro, A double pandemic: domestic violence in the age of COVID 19, Council on Foreign Relations. https://www.cfr.org/in-brief/double-pandemic-domestic-violence-age-covid-19, 2020). While this awareness was much discussed, assistance to survivors of abuse was limited because survivors often could not reach out for help, nor could advocates wishing to offer assistance safely reach in to advise them (Taub, A new Covid-19 crisis: domestic abuse rises worldwide. https://www.nytimes.com/2020/04/06/world/coronavirus-domestic-violence.html, 2020). The ever-present influence of the abuser prevented or limited the delivery of effective aid in many cases (Taub, A new Covid-19 crisis: domestic abuse rises worldwide. https://www.nytimes.com/2020/04/06/world/coronavirus-domestic-violence.html, 2020). But this was not the first disaster to place those experiencing intimate partner abuse at greater risk. Other disasters have in various ways increased womenâs safety risks both during and after crisis. Other crises routinely resulted in increased abuse of survivors in intimate partner relationships including sexual and other assault by intimate partners (Rao 2020; Sohrabizadeh Prehosp Disaster Med, 31(4):407â412. https://www.ncbi.nlm.nih.gov/pubmed/27212204, 2016). This chapter briefly identifies some forms of abuse experienced by women outside of the home during times of crisis and their connection to intimate partner abuse. Then, the impact of COVID-19 on intimate partner survivors will be explored and some of their experiences described. Gaps and flaws in nationsâ approaches to gender violence are often highlighted during and after disasters. Lack of planning to protect survivors of intimate partner violence and other highly vulnerable populations during crises was exacerbated by the additional dangers brought by COVID-19. Primarily, the heightened dangers resulted from stay-at-home orders, which made services for abused partners more difficult to obtain and highlighted the possibility of unintended consequences resulting from policies designed to protect the public as a whole (Godin 2020). This chapter concludes by considering what has been lacking in strategic disaster planning, including what lessons have been learned thus far through the COVID-19 experience. Recommendations for effective disaster planning to protect survivors of intimate partner abuse, while also protecting other vulnerable populations, are suggested. This information is presented with the caution that as of this writing the global pandemic continues to limit access to hard data. Long-term analysis of the implications of the pandemic on Intimate Partner Violence (IPV) survivors awaits the passage of time
Nucleosynthesis in Massive Stars With Improved Nuclear and Stellar Physics
We present the first calculations to follow the evolution of all stable
nuclei and their radioactive progenitors in stellar models computed from the
onset of central hydrogen burning through explosion as Type II supernovae.
Calculations are performed for Pop I stars of 15, 19, 20, 21, and 25 M_sun
using the most recently available experimental and theoretical nuclear data,
revised opacity tables, neutrino losses, and weak interaction rates, and taking
into account mass loss due to stellar winds. A novel ``adaptive'' reaction
network is employed with a variable number of nuclei (adjusted each time step)
ranging from about 700 on the main sequence to more than 2200 during the
explosion. The network includes, at any given time, all relevant isotopes from
hydrogen through polonium (Z=84). Even the limited grid of stellar masses
studied suggests that overall good agreement can be achieved with the solar
abundances of nuclei between 16O and 90Zr. Interesting discrepancies are seen
in the 20 M_sun model and, so far, only in that model, that are a consequence
of the merging of the oxygen, neon, and carbon shells about a day prior to core
collapse. We find that, in some stars, most of the ``p-process'' nuclei can be
produced in the convective oxygen burning shell moments prior to collapse; in
others, they are made only in the explosion. Serious deficiencies still exist
in all cases for the p-process isotopes of Ru and Mo.Comment: 53 pages, 17 color figures (3 as separate GIF images), slightly
extended discussion and references, accepted by Ap
Tunnelling Studies of Two-Dimensional States in Semiconductors with Inverted Band Structure: Spin-orbit Splitting, Resonant Broadening
The results of tunnelling studies of the energy spectrum of two-dimensional
(2D) states in a surface quantum well in a semiconductor with inverted band
structure are presented. The energy dependence of quasimomentum of the 2D
states over a wide energy range is obtained from the analysis of tunnelling
conductivity oscillations in a quantizing magnetic field. The spin-orbit
splitting of the energy spectrum of 2D states, due to inversion asymmetry of
the surface quantum well, and the broadening of 2D states at the energies, when
they are in resonance with the heavy hole valence band, are investigated in
structures with different strength of the surface quantum well. A quantitative
analysis is carried out within the framework of the Kane model of the energy
spectrum. The theoretical results are in good agreement with the tunnelling
spectroscopy data.Comment: 29 pages, RevTeX, submitted in Phys.Rev.B. Figures available on
request from [email protected]
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