106 research outputs found
Resistance of Leishmania (Viannia) Panamensis to Meglumine Antimoniate or Miltefosine Modulates Neutrophil Effector Functions.
Leishmania (Viannia) panamensis (L. (V.) p.) is the main causative agent of cutaneous leishmaniasis in Colombia and is usually treated with either meglumine antimoniate (MA) or miltefosine (MIL). In recent years, there has been increasing evidence of the emergence of drug-resistance against these compounds. Neutrophils are known to play an important role in immunity against Leishmania. These cells are rapidly recruited upon infection and are also present in chronic lesions. However, their involvement in the outcome of infection with drug-resistant Leishmania has not been examined. In this study, human and murine neutrophils were infected in vitro with MA or MIL drug-resistant L. (V.) p. lines derived from a parental L. (V.) p. drug-susceptible strain. Neutrophil effector functions were assessed analyzing the production of reactive oxygen species (ROS), the formation of neutrophil extracellular trap (NET) and the expression of cell surface activation markers. Parasite killing by neutrophils was assessed using L. (V.) p. transfected with a luciferase reporter. We show here that MA and MIL-resistant L. (V.) p. lines elicited significantly increased NET formation and MA-resistant L. (V.) p. induced significantly increased ROS production in both murine and human neutrophils, compared to infections with the parental MIL and MA susceptible strain. Furthermore, neutrophils exposed to drug-resistant lines showed increased activation, as revealed by decreased expression of CD62L and increased expression of CD66b in human neutrophils yet presented higher survival within neutrophils than the drug-susceptible strain. These results provide evidence that parasite drug-susceptibility may influences neutrophil activation and function as well as parasite survival within neutrophils. Further investigaton of the inter-relationship of drug susceptibility and neutrophil effector function should contribute to better understanding of the factors involved in susceptibility to anti-Leishmania drugs
Criticality in the randomness-induced second-order phase transition of the triangular Ising antiferromagnet with nearest- and next-nearest-neighbor interactions
Using a Wang-Landau entropic sampling scheme, we investigate the effects of
quenched bond randomness on a particular case of a triangular Ising model with
nearest- () and next-nearest-neighbor () antiferromagnetic
interactions. We consider the case , for which the pure
model is known to have a columnar ground state where rows of nearest-neighbor
spins up and down alternate and undergoes a weak first-order phase transition
from the ordered to the paramagnetic state. With the introduction of quenched
bond randomness we observe the effects signaling the expected conversion of the
first-order phase transition to a second-order phase transition and using the
Lee-Kosterlitz method, we quantitatively verify this conversion. The emerging,
under random bonds, continuous transition shows a strongly saturating specific
heat behavior, corresponding to a negative exponent , and belongs to a
new distinctive universality class with , ,
and . Thus, our results for the critical exponents support
an extensive but weak universality and the emerged continuous transition has
the same magnetic critical exponent (but a different thermal critical exponent)
as a wide variety of two-dimensional (2d) systems without and with quenched
disorder.Comment: 17 pages, 6 figures, accepted for publication in Physica
Transfer Matrices and Partition-Function Zeros for Antiferromagnetic Potts Models. V. Further Results for the Square-Lattice Chromatic Polynomial
We derive some new structural results for the transfer matrix of
square-lattice Potts models with free and cylindrical boundary conditions. In
particular, we obtain explicit closed-form expressions for the dominant (at
large |q|) diagonal entry in the transfer matrix, for arbitrary widths m, as
the solution of a special one-dimensional polymer model. We also obtain the
large-q expansion of the bulk and surface (resp. corner) free energies for the
zero-temperature antiferromagnet (= chromatic polynomial) through order q^{-47}
(resp. q^{-46}). Finally, we compute chromatic roots for strips of widths 9 <=
m <= 12 with free boundary conditions and locate roughly the limiting curves.Comment: 111 pages (LaTeX2e). Includes tex file, three sty files, and 19
Postscript figures. Also included are Mathematica files data_CYL.m and
data_FREE.m. Many changes from version 1: new material on series expansions
and their analysis, and several proofs of previously conjectured results.
Final version to be published in J. Stat. Phy
Critical aspects of the random-field Ising model
We investigate the critical behavior of the three-dimensional random-field Ising model
(RFIM) with a Gaussian field distribution at zero temperature. By implementing a
computational approach that maps the ground-state of the RFIM to the maximum-flow
optimization problem of a network, we simulate large ensembles of disorder realizations of
the model for a broad range of values of the disorder strength h and
system sizes  = L3, with L â€Â 156. Our averaging procedure
outcomes previous studies of the model, increasing the sampling of ground states by a
factor of 103. Using well-established finite-size scaling schemes, the
fourth-orderâs Binder cumulant, and the sample-to-sample fluctuations of various
thermodynamic quantities, we provide high-accuracy estimates for the critical field
hc, as well as the critical exponents Μ,
ÎČ/Îœ, and ÎłÌ
/Μ of the correlation length, order parameter, and
disconnected susceptibility, respectively. Moreover, using properly defined noise to
signal ratios, we depict the variation of the self-averaging property of the model, by
crossing the phase boundary into the ordered phase. Finally, we discuss the controversial
issue of the specific heat based on a scaling analysis of the bond energy, providing
evidence that its critical exponent α â 0â
Anisotropy studies around the galactic centre at EeV energies with the Auger Observatory
Data from the Pierre Auger Observatory are analyzed to search for
anisotropies near the direction of the Galactic Centre at EeV energies. The
exposure of the surface array in this part of the sky is already significantly
larger than that of the fore-runner experiments. Our results do not support
previous findings of localized excesses in the AGASA and SUGAR data. We set an
upper bound on a point-like flux of cosmic rays arriving from the Galactic
Centre which excludes several scenarios predicting sources of EeV neutrons from
Sagittarius . Also the events detected simultaneously by the surface and
fluorescence detectors (the `hybrid' data set), which have better pointing
accuracy but are less numerous than those of the surface array alone, do not
show any significant localized excess from this direction.Comment: Matches published versio
Early life risk factors and their cumulative effects as predictors of overweight in Spanish children
Objectives: To explore early life risk factors of overweight/obesity at age 6 years and their cumulative effects on overweight/obesity at ages 2, 4 and 6 years.
Methods: Altogether 1031 Spanish children were evaluated at birth and during a 6-year follow-up. Early life risk factors included: parental overweight/obesity, parental origin/ethnicity, maternal smoking during pregnancy, gestational weight gain, gestational age, birth weight, caesarean section, breastfeeding practices and rapid infant weight gain collected via hospital records. Cumulative effects were assessed by adding up those early risk factors that significantly increased the risk of overweight/obesity. We conducted binary logistic regression models.
Results: Rapid infant weight gain (OR 2.29, 99% CI 1.54â3.42), maternal overweight/obesity (OR 1.93, 99% CI 1.27â2.92), paternal overweight/obesity (OR 2.17, 99% CI 1.44â3.28), Latin American/Roma origin (OR 3.20, 99% CI 1.60â6.39) and smoking during pregnancy (OR 1.61, 99% CI 1.01â2.59) remained significant after adjusting for confounders. A higher number of early life risk factors accumulated was associated with overweight/obesity at age 6 years but not at age 2 and 4 years.
Conclusions: Rapid infant weight gain, parental overweight/obesity, maternal smoking and origin/ethnicity predict childhood overweight/obesity and present cumulative effects. Monitoring children with rapid weight gain and supporting a healthy parental weight are important for childhood obesity prevention
Transfer matrices and partition-function zeros for antiferromagnetic Potts models. VI. Square lattice with special boundary conditions
We study, using transfer-matrix methods, the partition-function zeros of the
square-lattice q-state Potts antiferromagnet at zero temperature (=
square-lattice chromatic polynomial) for the special boundary conditions that
are obtained from an m x n grid with free boundary conditions by adjoining one
new vertex adjacent to all the sites in the leftmost column and a second new
vertex adjacent to all the sites in the rightmost column. We provide numerical
evidence that the partition-function zeros are becoming dense everywhere in the
complex q-plane outside the limiting curve B_\infty(sq) for this model with
ordinary (e.g. free or cylindrical) boundary conditions. Despite this, the
infinite-volume free energy is perfectly analytic in this region.Comment: 114 pages (LaTeX2e). Includes tex file, three sty files, and 23
Postscript figures. Also included are Mathematica files data_Eq.m,
data_Neq.m,and data_Diff.m. Many changes from version 1, including several
proofs of previously conjectured results. Final version to be published in J.
Stat. Phy
Diatreta Cups, Light in Roman Dining Spaces
Cage cups or Diatreta are ancient Roman glass vessels produced by creating a thick blown blank of glass that, once cooled down, is taken to a glass cutter or diatretarii. The latter would cut and carve away most of the glass leaving a transparent vessel inside and an open-work decoration separated through thin posts of glass. The work is very delicate and exclusive, produced within limited space in time with no record of similar vessels until the late 1800 (Donald B. Harden & Toynbee 1959, p.181). Many of these glass objects have good-will inscriptions or decorations that express the importance of drinking. As for their provenance, most âwhen found in context- have been found in pagan burials. Nevertheless some fragments have been found in Christian environments or with Christian motifs like the SzekszĂĄrd cup. The location of these finds is mostly in the Rhine area ânorthern Empire, when Milan was one of its capitals (Aquaro 2004)- but the actual extent of finds expand throughout the 4th century extent of the Roman Empire. Considering their typological analysis there are basically two types, beaker and bowl. Beakers are considered drinking vessels as they either display a legend or a mythological reference to drink or wine. Whereas a general consensus agrees that open bowl-form cups were hanging lamps (Whitehouse 1988, p.28) since the 1986 find of a diatreta bowl with copper alloy hanging attachments. It is clear these were luxury objects to be used in special occasions and spaces. The aim of this paper is to understand the space were socialisation and drinking took place and the importance of luxurious objects to adorn, display and use. The paper will also put forward the idea that the beaker shaped diatreta vessels, usually considered for drinking, could have been lamps that encouraged drinking and good will to the guests. This paper is structured to first consider an introduction to late luxury Roman glass and then analysing the typological shape of all, or most of the diatreta currently known; secondly, through assessment by the means of comparison, analyse the writings or decorations the vessels were endowed with. Thirdly, by describing and understanding the people and the space were these vessels would have been used, emphasise the beauty of illuminating such spaces with these vessels. According to Herodotus in his historical investigation â5th century-, dress habits and food regime are elements of extreme importance to understand a people (Caporusso et al. 2011, p.12). This idea is not only valid for Herodotusâ time but it is something anthropology uses time and again to explain different aspects in peopleâs way of life. Through food and its environment, the dining space, this paper will aim to put the cage cups into a social context in order to give emphasis to the hypothesis of light versus wine
Consenso colombiano de atenciĂłn, diagnĂłstico y manejo de la infecciĂłn por SARS-COV-2/COVID-19 en establecimientos de atenciĂłn de la salud Recomendaciones basadas en consenso de expertos e informadas en la evidencia
The âAsociaciĂłn Colombiana de InfectologĂaâ (ACIN) and the âInstituto de EvaluaciĂłn de Nuevas TecnologĂas de la Saludâ (IETS) created a task force to develop recommendations for Covid 19 health care diagnosis, management and treatment informed, and based, on evidence. Theses reccomendations are addressed to the health personnel on the Colombian context of health services. © 2020 Asociacion Colombiana de Infectologia. All rights reserved
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