7,140 research outputs found
Gapless Hamiltonians for the toric code using the PEPS formalism
We study Hamiltonians which have Kitaev's toric code as a ground state, and
show how to construct a Hamiltonian which shares the ground space of the toric
code, but which has gapless excitations with a continuous spectrum in the
thermodynamic limit. Our construction is based on the framework of Projected
Entangled Pair States (PEPS), and can be applied to a large class of
two-dimensional systems to obtain gapless "uncle Hamiltonians".Comment: 8 pages, 2 figure
Nesting Of Montezuma Quail In Mexico
Although Mexico has the greatest diversity of quail of any New World country, basic information on the ecology and life history of Mexican quails remains unknown. Our objective was to describe nest characteristics of the Montezuma quail (Cyrtonyx montezumae montezumae) in central Mexico. We searched for Montezuma quail nests within 8 counties in the state of México, Mexico during May–September 2003. We conducted nest searches along 66 transects (3–5 km × 40 m) distributed across 17 study sites. We recorded vegetation community, elevation, and nesting substrate for each nest. We measured nest characteristics: height, depth, nest entrance diameter, and orientation. If eggs were found, we recorded clutch size and egg mass, texture, color, and shape. We observed 324 quail and located 6 nests along a 254-km route. Nests were located at elevations ranging from 2,568–2,692 m above sea level. Mean (± standard deviation) nest height and depth were 122.2 ± 7.7 mm and 195 ± 61.8 mm, respectively. Nest entrance orientation for 5 of 6 nests was toward a southerly direction. Mean nest egg mass was 9.9 ± 0.1 g. Our study provides basic and descriptive information on a poorly known quail species in Mexico
The aquatic ecosystem, a good environment for the horizontal transfer of antimicrobial resistance and virulence-associated factors among extended spectrum beta-lactamases producing E. coli
One of the main public health problems nowadays is the increase of antimicrobial resistance,
both in the hospital environment and outside it (animal environment, food and aquatic ecosystems,
among others). It is necessary to investigate the virulence-associated factors and the ability of
horizontal gene transfer among bacteria for a better understanding of the pathogenicity and the
mechanisms of dissemination of resistant bacteria. Therefore, the objective of this work was to
detect several virulence factors genes (fimA, papC, papG III, cnf1, hlyA and aer) and to determine the
conjugative capacity in a wide collection of extended-spectrum β-lactamases-producing E. coli isolated
from different sources (human, food, farms, rivers, and wastewater treatment plants). Regarding
virulence genes, fimA, papC, and aer were distributed throughout all the studied environments, papG
III was mostly related to clinical strains and wastewater is a route of dissemination for cnf1 and hlyA.
Strains isolated from aquatic environments showed an average conjugation frequencies of 1.15 × 10−1
± 5 × 10−1
, being significantly higher than those observed in strains isolated from farms and food
(p < 0.05), with frequencies of 1.53 × 10−4 ± 2.85 × 10−4 and 9.61 × 10−4 ± 1.96 × 10−3
, respectively. The
reported data suggest the importance that the aquatic environment (especially WWTPs) acquires for
the exchange of genes and the dispersion of resistance. Therefore, specific surveillance programs of
AMR indicators in wastewaters from animal or human origin are needed, in order to apply sanitation
measures to reduce the burden of resistant bacteria arriving to risky environments as WWTPs
The aquatic ecosystem, a good environment for the horizontal transfer of antimicrobial resistance and virulence-associated factors among extended spectrum ß-lactamases producing E. coli
One of the main public health problems nowadays is the increase of antimicrobial resistance,
both in the hospital environment and outside it (animal environment, food and aquatic ecosystems,
among others). It is necessary to investigate the virulence-associated factors and the ability of
horizontal gene transfer among bacteria for a better understanding of the pathogenicity and the
mechanisms of dissemination of resistant bacteria. Therefore, the objective of this work was to
detect several virulence factors genes (fimA, papC, papG III, cnf1, hlyA and aer) and to determine the
conjugative capacity in a wide collection of extended-spectrum β-lactamases-producing E. coli isolated
from different sources (human, food, farms, rivers, and wastewater treatment plants). Regarding
virulence genes, fimA, papC, and aer were distributed throughout all the studied environments, papG
III was mostly related to clinical strains and wastewater is a route of dissemination for cnf1 and hlyA.
Strains isolated from aquatic environments showed an average conjugation frequencies of 1.15 × 10−1
± 5 × 10−1
, being significantly higher than those observed in strains isolated from farms and food
(p < 0.05), with frequencies of 1.53 × 10−4 ± 2.85 × 10−4 and 9.61 × 10−4 ± 1.96 × 10−3
, respectively. The
reported data suggest the importance that the aquatic environment (especially WWTPs) acquires for
the exchange of genes and the dispersion of resistance. Therefore, specific surveillance programs of
AMR indicators in wastewaters from animal or human origin are needed, in order to apply sanitation
measures to reduce the burden of resistant bacteria arriving to risky environments as WWTPs
Predicting performance in team games: The automatic coach
This is an electronic version of the paper presented at the 3rd International Conference on Agents and Artificial Intelligence, held in Rome on 2011A wide range of modern videogames involves a number of players collaborating to obtain a common goal.
The way the players are teamed up is usually based on a measure of performance that makes players with a
similar level of performance play together. We propose a novel technique based on clustering over observed
behaviour in the game that seeks to exploit the particular way of playing of every player to find other players
with a gameplay such that in combination will constitute a good team, in a similar way to a human coach.
This paper describes the preliminary results using these techniques for the characterization of player and team
behaviours. Experiments are performed in the domain of Soccerbots.This work has been partly supported by: Spanish
Ministry of Science and Education under grant
TIN2009-13692-C03-03, TIN2010-19872 and Spanish
Ministry of Industry under grant TSI, 020110-
2009-205
Law, Knowledge and Action in Suárez
This paper explores some presuppositions in Francisco Suárez’s theory of law. I intend to show that his doctrine of law can be understood more deeply attending to the role the intellect and the will play in its genesis, i.e. I intend to construct a view of the grounding of the law in the moral psychology of Francisco Suárez. The interaction between the intellect and the will make way for the recognition of the goodness of beings and the openness of human nature to formulate different practical courses of action and to self-determine itself towards those concrete forms of goodness. A comparison with the animal-sensitive circuit of action will be offered as a contrast
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