731 research outputs found
Comparison of parasite loads in serum and blood samples from patients in acute and chronic phases of Chagas disease
Molecular methods have been developed for the detection and quantification of Trypanosoma cruzi DNA in blood samples from patients with Chagas disease. However, aspects of sample processing necessary for quantitative real-time PCR (qPCR), such as the addition of guanidine hydrochloride to whole blood samples, may limit timely access to molecular diagnosis. We analysed 169 samples from serum and guanidine-EDTA blood (GEB) obtained from patients in acute and chronic phases of Chagas disease. We applied qPCR targeted to the satellite DNA region. Finally, we compared the parasite loads and cycle of threshold values of the qPCR. The results confirmed the usefulness of serum samples for the detection and quantification of parasite DNA in patients with Chagas disease, especially in the acute phase. However, the parasite loads detected in serum samples from patients in the chronic phase were lower than those detected in GEB samples. The epidemiological implications of the findings are herein discussed. © Cambridge University Press 2018
Early Effects Of Estrogen On The Rat Ventral Prostate.
Complex interactions between androgen and estrogen (E2) regulate prostatic development and physiology. We analyzed the early effects of a high single dose of E2 (25 mg/kg body weight) and castration (separately or combined) on the adult 90-day-old male Wistar rat ventral prostate. Androgen levels, prostate weight, and the variation in the relative and absolute volume of tissue compartments and apoptotic indices were determined for 7 days. Castration and exogenous E2 markedly reduced ventral prostate weight (about 50% of the control), with a significant reduction in the epithelial compartment and increased stroma. The final volume of the epithelium was identical at day 7 for all treatments (58.5% of the control). However, E2 had an immediate effect, causing a reduction in epithelial volume as early as day 1. An increase in smooth muscle cell volume resulted from the concentration of these cells around the regressing epithelium. The treatments resulted in differential kinetics in epithelial cell apoptosis. Castration led to a peak in apoptosis at day 3, with 5% of the epithelial cells presenting signs of apoptosis, whereas E2 caused an immediate increase (observed on day 1) and a sustained (up to day 7) effect. E2 administration to castrated rats significantly increased the level of apoptosis by day 3, reaching 9% of the epithelial cells. The divergent kinetics between treatments resulted in the same levels of epithelial regression after 7 days (approximately 30% of control). These results show that E2 has an immediate and possibly direct effect on the prostate, and anticipates epithelial cell death before reducing testosterone to levels as low as those of castrated rats. In addition, E2 and androgen deprivation apparently cause epithelial cell death by distinct and independent pathways.38487-9
TEORÍA DE LA MENTE EN TAREAS DE FALSA CREENCIA Y PRODUCCIÓN NARRATIVA EN PREESCOLARES: INVESTIGACIONES CONTEMPORÁNEAS/ THEORY OF MIND IN FALSE BELIEF TASKS AND NARRATIVE PRODUCTION IN PRESCHOOLERS: CONTEMPORARY RESEARCH/ TEORIA DA MENTE EM TAREFAS DE FALSA CRENÇA E PRODUÇÃO NARRATIVA EM PRÉ-ESCOLARES: INVESTIGAÇÕES CONTEMPORÂNEAS
Este artículo presenta una reflexión sobre el desarrollo de la producción narrativa y el de la teoría de la mente en la etapa preescolar. En cada campo se plantean sus bases conceptuales, reportes y evidencias investigativas. Se muestra que en la producción narrativa los niños adquieren de manera relativamente tardía en su primera infancia las primeras habilidades que les permiten organizar una narración para contarla a otros. Se señala, además, que el desarrollo de la teoría de la mente está relacionado con el del lenguaje, aunque se cuenta con menos estudios sobre su relación con la producción narrativa. Se identifica la necesidad de un marco integrador de las explicaciones de las variantes conceptuales y metodológicas planteadas en esta reflexión
El lenguaje político: transformaciones y teorías
El artículo analiza la transformación que se produce en el lenguaje político a partir de las traducciones al latín de las obras éticas y políticas de Aristóteles en el siglo XIII. Se destaca el papel central de Tomás de Aquino, que inaugura la tradición tomista dentro de la cual se elabora un paradigma político que tiene el reino como núcleo. Dentro de este paradigma el rey no es caracterizado desde el punto de vista del poder, sino como “vicario de la multitud”. Esta tradición política es alternativa al republicanismo de algunos pensadores políticos italianos y a la razón de estado que acabará triunfando en la modernidad. El artículo habla de un humanismo tomista alternativo a los otros humanismos del renacimiento.This article analyses the transformation of political language initiated with the Latin translations of Aristotle’s ethical and political works in the 13th century. This transformation gives rise to a political paradigm that gravitates around the notion of a kingdom. In this paradigm, in which Aquinas plays a central role, the king is not characterised any longer by his wielding power, but by his being a “people’s vicar”. This political tradition contrasts both with the republicanism of some Italian politicians of the time, and with the Modern understanding of a nation-state. This article deals with Thomistic humanism as a rival to other humanistic views of the Renaissance
Primes and composites in the determinant Hosoya triangle
In this paper, we look at numbers of the form
. These numbers are the entries of a
triangular array called the \emph{determinant Hosoya triangle} which we denote
by . We discuss the divisibility properties of the above numbers
and their primality. We give a small sieve of primes to illustrate the density
of prime numbers in . Since the Fibonacci and Lucas numbers
appear as entries in , our research is an extension of the
classical questions concerning whether there are infinitely many Fibonacci or
Lucas primes. We prove that has arbitrarily large neighbourhoods
of composite entries. Finally we present an abundance of data indicating a very
high density of primes in .Comment: two figure
Horizontal gene transfer to a defensive symbiont with a reduced genome in a multipartite beetle microbiome
Symbiotic mutualisms of bacteria and animals are ubiquitous in nature, running a continuum from facultative to obligate from the perspectives of both partners. The loss of functions required for living independently but not within a host gives rise to reduced genomes in many symbionts. Although the phenomenon of genome reduction can be explained by existing evolutionary models, the initiation of the process is not well understood. Here, we describe the microbiome associated with the eggs of the beetle Lagria villosa, consisting of multiple bacterial symbionts related to Burkholderia gladioli, including a reduced-genome symbiont thought to be the exclusive producer of the defensive compound lagriamide. We show that the putative lagriamide-producing symbiont is the only member of the microbiome undergoing genome reduction and that it has already lost the majority of its primary metabolism and DNA repair pathways. The key step preceding genome reduction in the symbiont was likely the horizontal acquisition of the putative lagriamide lga biosynthetic gene cluster. Unexpectedly, we uncovered evidence of additional horizontal transfers to the symbiont's genome while genome reduction was occurring and despite a current lack of genes needed for homologous recombination. These gene gains may have given the genome-reduced symbiont a selective advantage in the microbiome, especially given the maintenance of the large lga gene cluster despite ongoing genome reduction. IMPORTANCE Associations between microorganisms and an animal, plant, or fungal host can result in increased dependence over time. This process is due partly to the bacterium not needing to produce nutrients that the host provides, leading to loss of genes that it would need to live independently and to a consequent reduction in genome size. It is often thought that genome reduction is aided by genetic isolation-bacteria that live in monocultures in special host organs, or inside host cells, have less access to other bacterial species from which they can obtain genes. Here, we describe exposure of a genome-reduced beetle symbiont to a community of related bacteria with nonreduced genomes. We show that the symbiont has acquired genes from other bacteria despite going through genome reduction, suggesting that isolation has not yet played a major role in this case of genome reduction, with horizontal gene gains still offering a potential route for adaptation
On the sensitivity reach of LQ production with preferential couplings to third generation fermions at the LHC
Leptoquarks (LQs) are hypothetical particles that appear in various
extensions of the Standard Model (SM) that can explain observed differences
between SM theory predictions and experimental results. The production of these
particles has been widely studied at various experiments, most recently at the
Large Hadron Collider (LHC), and stringent bounds have been placed on their
masses and couplings, assuming the simplest beyond-SM (BSM) hypotheses.
However, the limits are significantly weaker for LQ models with family
non-universal couplings containing enhanced couplings to third-generation
fermions. We present a new study on the production of a LQ at the LHC, with
preferential couplings to third-generation fermions, considering proton-proton
collisions at and
. Such a hypothesis is well motivated theoretically and it can
explain the recent anomalies in the precision measurements of
-meson decay rates, specifically the ratios. Under a
simplified model where the LQ masses and couplings are free parameters, we
focus on cases where the LQ decays to a lepton and a quark,
and study how the results are affected by different assumptions about chiral
currents and interference effects with other BSM processes with the same final
states, such as diagrams with a heavy vector boson, . The
analysis is performed using machine learning techniques, resulting in an
increased discovery reach at the LHC and allowing us to probe the entirety of
the new physics phase space which addresses the -meson anomalies,
for LQ masses up to 2.25 .Comment: 26 pages, 13 figure
Antibiotic-producing symbionts dynamically transition between plant pathogenicity and insect-defensive mutualism
Pathogenic and mutualistic bacteria associated with eukaryotic hosts often lack distinctive genomic features, suggesting regular transitions between these lifestyles. Here we present evidence supporting a dynamic transition from plant pathogenicity to insect-defensive mutualism in symbiotic Burkholderia gladioli bacteria. In a group of herbivorous beetles, these symbionts protect the vulnerable egg stage against detrimental microbes. The production of a blend of antibiotics by B. gladioli, including toxoflavin, caryoynencin and two new antimicrobial compounds, the macrolide lagriene and the isothiocyanate sinapigladioside, likely mediate this defensive role. In addition to vertical transmission, these insect symbionts can be exchanged via the host plant and retain the ability to initiate systemic plant infection at the expense of the plant’s fitness. Our findings provide a paradigm for the transition between pathogenic and mutualistic lifestyles and shed light on the evolution and chemical ecology of this defensive mutualism
Microsolvation of NO3 -: Structural exploration and bonding analysis
Exploration of the potential energy surfaces (PESs) of various microsolvated species associated with the microsolvation of the nitrate anion using density functional theory methods uncovers a rich and complex structural diversity previously unnoticed in the scientific literature for the [NO3(H2O)n]−, n = 1–6 clusters. Two types of interactions are at play in stabilizing the clusters: traditional water to water and charge assisted nitrate to water hydrogen bonds (HBs). The formal negative charge on oxygen atoms in nitrate strengthens hydrogen bonding among water molecules. There is outstanding agreement between available experimental data (sequential hydration enthalpies, IR spectra, and vertical detachment energies) and the corresponding expectation values obtained from our structures. Each PES is heavily populated in the vicinities of the corresponding global minimum with multiple structures contributing to the experimental properties. The last two statements, in conjunction with results from other works (see for example Phys. Chem. Chem. Phys. 2014, 16, 19241) place a warning on the generalized and naive practice of assigning experimental observations to individual structures
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