7,556 research outputs found
Non-Abelian Vortices on the Torus
We study periodic arrays of non-Abelian vortices in an
gauge theory with flavors of fundamental matter multiplets. We carefully
discuss the corresponding twisted boundary conditions on the torus and propose
an ansatz to solve the first order Bogomolnyi equations which we find by
looking to a bound of the energy. We solve the equations numerically and
construct explicit vortex solutions
Power scaling rules for charmonia production and HQEFT
We discuss the power scaling rules along the lines of a complete Heavy Quark
Effective Field Theory (HQEFT) for the description of heavy quarkonium
production through a color-octet mechanism. To this end, we firstly derive a
tree-level heavy quark effective Lagrangian keeping both particle-antiparticle
mixed sectors allowing for heavy quark-antiquark pair annihilation and
creation, but describing only low-energy modes around the heavy quark mass.
Then we show the consistency of using HQEFT fields in constructing four-fermion
local operators a la NRQCD, to be identified with standard color-octet matrix
elements. We analyze some numerical values extracted from charmonia production
by different authors and their hierarchy in the light of HQEFT.Comment: LaTeX, 19 pages, 3 EPS figure
A heavy quark effective field lagrangian keeping particle and antiparticle mixed sectors
We derive a tree-level heavy quark effective Lagrangian keeping
particle-antiparticle mixed sectors allowing for heavy quark-antiquark pair
annihilation and creation. However, when removing the unwanted degrees of
freedom from the effective Lagrangian one has to be careful in using the
classical equations of motion obeyed by the effective fields in order to get a
convergent expansion on the reciprocal of the heavy quark mass. Then the
application of the effective theory to such hard processes should be sensible
for special kinematic regimes as for example heavy quark pair production near
threshold.Comment: LaTeX, 14 pages, 1 EPS figure
Integration of hydrothermal liquefaction and carbon capture and storage for the production of advanced liquid biofuels with negative CO2 emissions
The technical and economic feasibility to deliver sustainable liquid biocrude
through hydrothermal liquefaction (HTL) while enabling negative carbon dioxide
emissions is evaluated in this paper, looking into the potential of the process
in the context of negative emission technologies (NETs) for climate change
mitigation. In the HTL process, a gas phase consisting mainly of carbon dioxide
is obtained as a side product driving a potential for the implementation of
carbon capture and storage in the process (BECCS) that has not been explored
yet in the existing literature and is undertaken in this study. To this end,
the process is divided in a standard HTL base and a carbon capture add-on,
having forestry residues as feedstock. The Selexol technology is adapted in a
novel scheme to simultaneously separate the CO2 from the HTL gas and recover
the excess hydrogen for biocrude upgrading. The cost evaluation indicates that
the additional cost of the carbon capture can be compensated by revenues from
the excess process heat and the European carbon allowance market. The impact in
the MFSP of the HTL base case ranges from -7% to 3%, with -15% in the most
favorable scenario, with a GHG emissions reduction potential of 102-113%
compared to the fossil baseline. These results show that the implementation of
CCS in the HTL process is a promising alternative from technical, economic and
environmental perspective in future scenarios in which advanced liquid biofuels
and NETs are expected to play a role in the decarbonization of the energy
system
Effects of maternal subnutrition during early pregnancy on cow hematological profiles and offspring physiology and vitality in two beef breeds
This experiment evaluated the effects of subnutrition during early gestation on hematology in cows (Bos Taurus) and on hematological, metabolic, endocrine, and vitality parameters in their calves. Parda de Montaña and Pirenaica dams were inseminated and assigned to either a control (CONTROL, 100% requirements) or a nutrient‐restricted group (SUBNUT, 65%) during the first third of gestation. Dam blood samples were collected on days 20 and 253 of gestation, and calf samples were obtained during the first days of life. Pirenaica dams presented higher red series parameters than Parda de Montaña dams, both in the first and the last months of gestation. During early pregnancy, granulocyte numbers and mean corpuscular hemoglobin were lower in Pirenaica‐SUBNUT than in Pirenaica‐CONTROL cows. Calves from the SUBNUT cows did not show a physiological reduction in red series values in early life, suggesting later maturation of the hematopoietic system. Poor maternal nutrition affected calf endocrine parameters. Newborns from dystocic parturitions showed lower NEFA concentrations and weaker vitality responses. In conclusion, maternal nutrition had short‐term effects on cow hematology, Pirenaica cows showing a higher susceptibility to undernutrition; and a long‐term effect on their offspring endocrinology, SUBNUT newborns showing lower levels of IGF‐1 and higher levels of cortisol.This work was supported by the Spanish Ministry of Economy and Business and the European Union Regional Development Funds (INIA RTA 2013‐00059‐C02 and INIA RZP 2015‐001) and the Government of Aragon under the Grant Research Group Funds (A14_17R). A. Noya received a PhD grant from INIA‐Government of Aragon
Applying MAPP Algorithm for Cooperative Path Finding in Urban Environments
The paper considers the problem of planning a set of non-conflict
trajectories for the coalition of intelligent agents (mobile robots). Two
divergent approaches, e.g. centralized and decentralized, are surveyed and
analyzed. Decentralized planner - MAPP is described and applied to the task of
finding trajectories for dozens UAVs performing nap-of-the-earth flight in
urban environments. Results of the experimental studies provide an opportunity
to claim that MAPP is a highly efficient planner for solving considered types
of tasks
Einstein-Maxwell gravitational instantons and five dimensional solitonic strings
We study various aspects of four dimensional Einstein-Maxwell multicentred
gravitational instantons. These are half-BPS Riemannian backgrounds of minimal
N=2 supergravity, asymptotic to R^4, R^3 x S^1 or AdS_2 x S^2. Unlike for the
Gibbons-Hawking solutions, the topology is not restricted by boundary
conditions. We discuss the classical metric on the instanton moduli space. One
class of these solutions may be lifted to causal and regular multi `solitonic
strings', without horizons, of 4+1 dimensional N=2 supergravity, carrying null
momentum.Comment: 1+30 page
High- production as signals for Double Parton scattering at hadron colliders
We present an analysis of the \psi\psi production from double parton (DP)
sacttering and single parton (SP) scattering in the large p_T region via
color-octet gluon fragmentation. We find that at the Tevatron the DP \psi\psi
production is at the edge of the detectability at present, and at the LHC the
DP cross section will dominate over the SP cross section in the lower p_T(min)
region (i.e., p_T(min)<7GeV). We also conclude that the color-octet mechanism
is of crucial importance to the double j/psi production at high energy hadron
colliders.Comment: Revtex, 12 pages, 3 Postscript figure
Silicon-based three-dimensional microstructures for radiation dosimetry in hadrontherapy
In this work, we propose a solid-state-detector for use in radiation microdosimetry. This device improves the performance of existing dosimeters using customized 3D-cylindrical microstructures etched inside silicon. The microdosimeter consists of an array of micro-sensors that have 3D-cylindrical electrodes of 15 μm diameter and a depth of 5 μm within a silicon membrane, resulting in a well-defined micrometric radiation sensitive volume. These microdetectors have been characterized using an 241Am source to assess their performance as radiation detectors in a high-LET environment. This letter demonstrates the capability of this microdetector to be used to measure dose and LET in hadrontherapy centers for treatment plan verification as part of their patient-specific quality control program
- …