201 research outputs found
The complement: a solution to liquid drop finite size effects in phase transitions
The effects of the finite size of a liquid drop undergoing a phase transition
are described in terms of the complement, the largest (but still mesoscopic)
drop representing the liquid in equilibrium with the vapor. Vapor cluster
concentrations, pressure and density from fixed mean density lattice gas
(Ising) model calculations are explained in terms of the complement. Accounting
for this finite size effect is key to determining the infinite nuclear matter
phase diagram from experimental data.Comment: Four two column pages, four figures, two tables; accepted for
publication in PR
Youth unemployment, community violence, creating opportunities in Dar es Salaam, Tanzania: a qualitative study
Background: Tanzania has consistently shown in recent decades to have a high overall crime rate. Although its homicide rate is moderate, Dar es Salaam has an unusually high amount of community violence; more than half of all homicides were due to lynching and vigilantism. Most of these homicides were a reaction to petty theft of purses, cell phones, and domestic meat animals. Employment is hypothesized to decrease petty theft and the resulting homicidal community violence. The objective of this research is to characterize appropriate interventions.Methods: In-depth interviews took place with proxy respondents of youth who had been killed through community violence. Most respondents were relatives of youth killed by community violence or youth who had directly experienced community violence. A focus group was held with at risk youth.Results:  “Lack of employment” was the largest node in terms of number of references and sources. It is reported with “Business Ability” and “Normal Life”. Occupational categories for uneducated youth in Dar es Salaam are: formal employment, agriculture, petty business, and day labour. Stealing, begging and emigration occur when other options have failed. Suggestions for decreasing death by community violence fell into three categories, all to do with employment: employment creation, working with youth in groups, and creating a supportive environment for small enterprises.Conclusions: Productive occupations are needed, including the revivification of traditional natural resource based industries such as fisheries and forestry. The physical and legal environment must be made conducive for “self-employed non-agricultural workers”. To optimize potential effectiveness, rigorous experimental research should be conducted, to facilitate humane, equitable, and environmentally sound scale up of youth employment opportunities
HAVOSS: A Maturity Model for Handling Vulnerabilities in Third Party OSS Components
Security has been recognized as a leading barrier for IoT adoption. The growing number of connected devices and reported software vulnerabilities increases the importance firmware updates. Maturity models for software security do include parts of this, but are lacking in several aspects. This paper presents and evaluates a maturity model (HAVOSS) for handling vulnerabilities in third party OSS and COTS components. The maturity model was designed by first reviewing industry interviews, current best practice guidelines and other maturity models. After that, the practices were refined through industry interviews, resulting in six capability areas covering in total 21 practices. These were then evaluated based on their importance according to industry experts. It is shown that the practices are seen as highly important, indicating that the model can be seen as a valuable tool when assessing strengths and weaknesses in an organization's ability to handle firmware updates
Simple analytic solution of fireball hydrodynamics
A new family of simple analytic solutions of hydrodynamics is found for
non-relativistic, rotationally symmetric fireballs assuming an ideal gas
equation of state. The solution features linear flow profile and a non-trivial
transverse temperature profile. The radial temperature gradient vanishes only
in the collisionless gas limit. The Zimanyi-Bondorf-Garpman solution and the
Buda-Lund parameterization of expanding hydrodynamical sources are recovered as
special cases. The results are applied to predict new features of proton-proton
correlations and spectra data at 1.93 AGeV Ni + Ni reactions.Comment: Latex, Revte
Correlation functions and emission time sequence of light charged particles from projectile-like fragment source in E/A = 44 and 77 MeV 40Ar + 27Al collisions
Two-particle correlation functions, involving protons, deuterons, tritons,
and alpha-particles, have been measured at very forward angles (0.7 deg <
theta_lab < 7 deg), in order to study projectile-like fragment (PLF) emission
in E/A = 44 and 77 MeV 40Ar + 27Al collisions. Peaks, originating from
resonance decays, are larger at E/A = 44 than at 77 MeV. This reflects the
larger relative importance of independently emitted light particles, as
compared to two-particle decay from unstable fragments, at the higher beam
energy. The time sequence of the light charged particles, emitted from the PLF,
has been deduced from particle-velocity-gated correlation functions (discarding
the contribution from resonance decays). Alpha-particles are found to have an
average emission time shorter than protons but longer than tritons and
deuterons.Comment: 18 pages, 5 figures, submitted to Nuclear Physics
N N bar,Delta bar N, Delta N bar excitation for the pion propagator in nuclear matter
The particle-hole and Delta -hole excitations are well-known elementary
excitation modes for the pion propagator in nuclear matter. But, the excitation
also involves antiparticles, namely, nucleon-antinucleon, anti-Delta-nucleon
and Delta-antinucleon excitations. These are important for high-energy momentum
as well, and have not been studied before, to our knowledge. In this paper, we
give both the formulas and the numerical calculations for the real and the
imaginary parts of these excitations.Comment: Latex, 3 eps file
Quantum-Statistical Correlations and Single Particle Distributions for Slowly Expanding Systems with Temperature Profile
Competition among particle evaporation, temperature gradient and flow is
investigated in a phenomenological manner, based on a simultaneous analysis of
quantum statistical correlations and momentum distributions for a
non-relativistic, spherically symmetric, three-dimensionally expanding, finite
source. The parameters of the model emission function are constrained by fits
to neutron and proton momentum distributions and correlation functions in
intermediate energy heavy-ion collisions. The temperature gradient is related
to the momentum dependence of the radius parameters of the two-particle
correlation function, as well as to the momentum-dependent temperature
parameter of the single particle spectrum, while a long duration of particle
evaporation is found to be responsible for the low relative momentum behavior
of the two-particle correlations.Comment: 20 pages + 5 ps figures, ReVTeX, uses psfig.sty, the description is
extended to include final state interactions, phenomenological evaporation
and to fit intermediate energy heavy ion proton and neutron spectrum and
correlation dat
Investigation of Zero-Sound Dispersion Equation in the Complex Plane of Frequency
The known solutions to the zero-sound dispersion equation are considered as
placed on the physical and unphysical sheets in the complex plane of frequency.Comment: 15 pages, 7 figure
Delta excitation in K^+-nucleus collisions
We present calculations for \Delta excitation in the (K^+,K^+) reaction in
nuclei. The background from quasielastic K^+ scattering in the \Delta region is
also evaluated and shown to be quite small in some kinematical regions, so as
to allow for a clean identification of the \Delta excitation strength. Nuclear
effects tied to the \Delta renormalization in the nucleus are considered and
the reaction is shown to provide new elements to enrich our knowledge of the
\Delta properties in a nuclear medium.Comment: 11 pages, 6 figures, LaTe
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