1,457 research outputs found
Non-relativistic bound states at finite temperature (II): the muonic hydrogen
We illustrate how to apply modern effective field theory techniques and
dimensional regularization to factorise the various scales which appear in QED
bound states at finite temperature. We focus here on the muonic hydrogen atom.
Vacuum polarization effects make the physics of this atom at finite temperature
very close to that of heavy quarkonium states. We comment on the implications
of our results for these states in the quark gluon plasma. In particular, we
estimate the effects of a finite charm quark mass in the dissociation
temperature of bottomonium.Comment: 22 pages, 8 figures. Journal version, reference adde
Latin American perspectives and the IT2017 curricular guidelines
The term information technology has many meanings for various stakeholders and continues to evolve. This discussion presents an overview of the developing curricular guidelines for rigorous, high quality, bachelor\u27s degree programs in information technology (IT), called IT2017. Panel participants will focus on Latin American academic and industry perspectives on IT undergraduate education. Discussion will seek to ascertain commonalities and differences between the current draft IT2017 report and perspectives from Latino/a professional and academic communities. It also addresses ways in which this endeavor contrasts with current practices in Latin America industry and academia
Peruvian weapon system acquisition process
Historically, the acquisition of a weapon systems in the Republic of Peru has been made on the basis of system effectiveness and initial acquisition cost, with little or no consideration being given to operating and support costs that will be incurred after the system is deployed in the field. Peru acquires most of its sophisticated weapon systems from foreign countries. Under this situation, broad understanding of Life Cycle Cost (LCC) concept and techniques are needed. This thesis introduces the LCC concept, life cycle costing techniques and the methodology for Life Cycle Cost analysis in Peruvian Weapon Systems acquisition process. The research aims to show the effects that United Foreign Military Sales has in the Third World, the technology transfer as a decisive influence on the daily lives of most of the world population and the Soviet Union's arms trade with the Third World, the life cycle concept in Peruvian weapon acquisition process, and its fit into known economic analysis techniques.http://archive.org/details/peruviweaponsyst1094527579Colonel, Peruvian Air ForceApproved for public release; distribution is unlimited
Self-similarity and long-time behavior of solutions of the diffusion equation with nonlinear absorption and a boundary source
This paper deals with the long-time behavior of solutions of nonlinear
reaction-diffusion equations describing formation of morphogen gradients, the
concentration fields of molecules acting as spatial regulators of cell
differentiation in developing tissues. For the considered class of models, we
establish existence of a new type of ultra-singular self-similar solutions.
These solutions arise as limits of the solutions of the initial value problem
with zero initial data and infinitely strong source at the boundary. We prove
existence and uniqueness of such solutions in the suitable weighted energy
spaces. Moreover, we prove that the obtained self-similar solutions are the
long-time limits of the solutions of the initial value problem with zero
initial data and a time-independent boundary source
Parallel Excluded Volume Tempering for Polymer Melts
We have developed a technique to accelerate the acquisition of effectively
uncorrelated configurations for off-lattice models of dense polymer melts which
makes use of both parallel tempering and large scale Monte Carlo moves. The
method is based upon simulating a set of systems in parallel, each of which has
a slightly different repulsive core potential, such that a thermodynamic path
from full excluded volume to an ideal gas of random walks is generated. While
each system is run with standard stochastic dynamics, resulting in an NVT
ensemble, we implement the parallel tempering through stochastic swaps between
the configurations of adjacent potentials, and the large scale Monte Carlo
moves through attempted pivot and translation moves which reach a realistic
acceptance probability as the limit of the ideal gas of random walks is
approached. Compared to pure stochastic dynamics, this results in an increased
efficiency even for a system of chains as short as monomers, however
at this chain length the large scale Monte Carlo moves were ineffective. For
even longer chains the speedup becomes substantial, as observed from
preliminary data for
Intake and Yield of \u3ci\u3eCynodon nlemfuensis\u3c/i\u3e Alone and Associated with \u3ci\u3eLeucaena leucocephala\u3c/i\u3e Grazed by Sheep
The objective of the present study was to determine dry matter intake (DMI) and the forage yield of green dry matter (GDM) of star grass (Cynodon nlemfuensis) alone and associated with Leucaena leucocephala cv. Perú grazed by sheep. The experimental treatments were: Systems T1) Star grass alone, and T2) Star grass + L. leucocephala. These treatments were evaluated during three seasons (i.e. Late-rainy, Dry and Rainy seasons). The availability of forage was lower (P \u3c 0.0001) in T1, 2543 kg GDM/ha, than with T2, 3092 kg GDM/ha. Green dry matter in the rainy season was greater (P \u3c 0.0001), with 3910 kg GDM/ha, than in the late-rainy and dry seasons, 2492 and 2052 kg GDM/ha, respectively. DMI was 5.9 and 7.6 g DM/kg of LW 0.75/hour for the T1 and T2, respectively (P \u3c 0.0001). DMI during the rainy season was lower (P \u3c 0.01) than that of the dry and late-rainy seasons, 6.2, 6.4 and 7.5 g DM/kg LW0.75/hour, respectively. The association C. nlemfuensis-L. leucocephala increased the availability of forage and the voluntary intake
Does greening of neotropical cities considerably mitigate carbon dioxide emissions? The case of Medellin, Colombia
Cities throughout the world are advocating highly promoted tree plantings as a climate change mitigation measure. Assessing the carbon offsets associated with urban trees relative to other climate change policies is vital for sustainable development, planning, and solving environmental and socio-economic problems, but is difficult in developing countries. We estimated and assessed carbon dioxide (CO2) storage, sequestration, and emission offsets by public trees in the Medellin Metropolitan Area, Colombia, as a viable Nature-Based Solution for the Neotropics. While previous studies have discussed nature-based solutions and explored urban tree carbon dynamics in high income countries, few have been conducted in tropical cities in low-middle income countries, particularly within South America. We used a public tree inventory for the Metropolitan Area of the Aburrá Valley and an available urban forest functional model, i-Tree Streets, calibrated for Colombia's context. We found that CO2 offsets from public trees were not as effective as cable cars or landfills. However, if available planting spaces are considered, carbon offsets become more competitive with cable cars and other air quality and socio-economic co-benefits are also provided. The use of carbon estimation models and the development of relevant carbon accounting protocols in Neotropical cities are also discussed. Our nature-based solution approach can be used to better guide management of urban forests to mitigate climate change and carbon offset accounting in tropical cities lacking available information. © 2017 by the authors
Descriptive Analysis of Emancipated Foster Youth Seeking Mental Health Treatment
Current and former foster youth experience increased risk for behavioral, cognitive, and emotional problems due to maltreatment and experiences in foster care. Nonetheless, research indicates a gap between the need for mental health services and service use. The current study describes a sample of self-referring, emancipated foster youth seeking long-term psychotherapy to understand reasons youth seek psychotherapy. This study further compares a subset of youths’ data with reports collected from respective therapists to examine differences in perceptions of symptoms
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