2,828 research outputs found

    Linking host morphology and symbiont performance in octocorals

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    Octocorals represent an important group in reef communities throughout the tropical seas and, like scleractinian corals, they can be found in symbiosis with the dinoflagellate Symbiodinium. However, while there is extensive research on this symbiosis and its benefits in scleractinians, research on octocorals has focused so far mainly on the host without addressing their symbiosis. Here, we characterized and compared the photophysiological features of nine Caribbean octocoral species with different colony morphologies (sea fan, plumes, whips and rods) and related key morphological features with their respective symbiont photobiology. Colony features (branch shape and thickness), as well as micromorphological features (polyp size, density), were found to be significantly correlated with symbiont performance. Sea fans and plumes, with thinner branches and smaller polyps, favor higher metabolic rates, compared to sea rods with thicker branches and larger polyps. Daily integrated photosynthesis to respiration ratios > 1 indicated that the autotrophic contribution to organisms’ energy demands was important in all species, but especially in sea whips. This information represents an important step towards a better understanding of octocoral physiology and its relationship to host morphology, and might also explain to some extent species distribution and susceptibility to environmental stress

    Salmonella Pathogenesis and Processing of Secreted Effectors by Caspase-3

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    The enteric pathogen Salmonella enterica serovar Typhimurium causes food poisoning resulting in gastroenteritis. The S. Typhimurium effector Salmonella invasion protein A (SipA) promotes gastroenteritis by functional motifs that trigger either mechanisms of inflammation or bacterial entry. During infection of intestinal epithelial cells, SipA was found to be responsible for the early activation of caspase-3, an enzyme that is required for SipA cleavage at a specific recognition motif that divided the protein into its two functional domains and activated SipA in a manner necessary for pathogenicity. Other caspase-3 cleavage sites identified in S. Typhimurium appeared to be restricted to secreted effector proteins, which indicates that this may be a general strategy used by this pathogen for processing of its secreted effectors

    Ep-CAM (MOC-31) expression in tooth germ and ameloblastoma

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    Ep-CAM, a transmembrane glycoprotein expressed in most epithelium in normal conditions, has diverse roles in these tissues, including in cell adhesion, proliferation, differentiation, cell cycle regulation, migration and intracellular signaling. It is also over-expressed in most malignant neoplasia, participating in the initiation, progression, and metastatic dissemination of the tumor. The expression and roles of this protein in oral neoplasia, particularly in odontogenic tumors, remain unestablished. The objective of this study consisted in analyzing the expression of this protein in ameloblastoma and tooth germ

    High serum alkaline phosphatase levels, a study in 181 Thai adult hospitalized patients

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    BACKGROUND: Alkaline phosphatase (ALP) is an important enzyme mainly derived from the liver, bones and in lesser amounts from intestines, placenta, kidneys and leukocytes. An increase in ALP levels in the serum is frequently associated with a variety of diseases. This study was done in order to determine the diseases associated with a high ALP level among Thai adult hospitalized patients. METHOD: A review was made of medical records of inpatients with high ALP level above 1000 IU/L in King Chulalongkorn Memorial Hospital, Thailand from January 1999 to December 1999. Excluded were cases of (a) patients who have bone involvements with malignancies, (b) pediatric patients younger than 15 years old and c) HIV-seropositive patients. RESULTS: A total of 181 hospitalized patients with eligible medical records were identified (96 males and 85 females, mean age 49.4 ± 16.1 years). Their ALP levels ranging from 1,001 to 3,067 IU/L, these patients were divided into four groups. CONCLUSION: High serum ALP levels in hospitalized patients were commonly found in three major groups having obstructive biliary diseases, infiltrative liver disease and sepsis. The study results were in accordance with previous reports in developed countries. Nonetheless, cholangiocarcionoma and some tropical diseases unique to our setting were also detected in these cases. where there was a marked elevation of serum ALP

    Subthreshold dynamics of the neural membrane potential driven by stochastic synaptic input

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    In the cerebral cortex, neurons are subject to a continuous bombardment of synaptic inputs originating from the network's background activity. This leads to ongoing, mostly subthreshold membrane dynamics that depends on the statistics of the background activity and of the synapses made on a neuron. Subthreshold membrane polarization is, in turn, a potent modulator of neural responses. The present paper analyzes the subthreshold dynamics of the neural membrane potential driven by synaptic inputs of stationary statistics. Synaptic inputs are considered in linear interaction. The analysis identifies regimes of input statistics which give rise to stationary, fluctuating, oscillatory, and unstable dynamics. In particular, I show that (i) mere noise inputs can drive the membrane potential into sustained, quasiperiodic oscillations (noise-driven oscillations), in the absence of a stimulus-derived, intraneural, or network pacemaker; (ii) adding hyperpolarizing to depolarizing synaptic input can increase neural activity (hyperpolarization-induced activity), in the absence of hyperpolarization-activated currents

    The GAPS Programme with HARPS-N at TNG XV. A substellar companion around a K giant star identified with quasi-simultaneous HARPS-N and GIANO measurements

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    Context. Identification of planetary companions of giant stars is made difficult because of the astrophysical noise, that may produce radial velocity (RV) variations similar to those induced by a companion. On the other hand any stellar signal is wavelength dependent, while signals due to a companion are achromatic. Aims. Our goal is to determine the origin of the Doppler periodic variations observed in the thick disk K giant star TYC 4282-605-1 by HARPS-N at the Telescopio Nazionale Galileo (TNG) and verify if they can be due to the presence of a substellar companion. Methods. Several methods have been used to exclude the stellar origin of the observed signal including detailed analysis of activity indicators and bisector and the analysis of the photometric light curve. Finally we have conducted an observational campaign to monitor the near infrared (NIR) RV with GIANO at the TNG in order to verify whether the NIR amplitude variations are comparable with those observed in the visible. Results. Both optical and NIR RVs show consistent variations with a period at 101 days and similar amplitude, pointing to the presence of a companion orbiting the target. The main orbital properties obtained for our giant star with a derived mass of M=0.97+-0.03M_sun are M_Psini=10.78+-0.12MJ;P=101.54+-0.05days;e=0.28+-0.01 and a=0.422+-0.009AU. The chemical analysis shows a significant enrichment in the abundance of Nai, Mgi, Ali and S i while the rest of analyzed elements are consistent with the solar value demonstrating that the chemical composition corresponds with an old K giant (age = 10.1 Gyr) belonging to local thick disk. Conclusions. We conclude that the substellar companion hypothesis for this K giant is the best explanation for the observed periodic RV variation. This study also shows the high potential of multi-wavelength RV observations for the validation of planet candidates.Comment: Accepted in Journal reference A&A 14/06/201

    Comparación del efecto osmodeshidratante de distintos solutos en pulpa de membrillo.

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    La deshidratación osmótica (DO) consiste en la inmersión de un alimento en una solución hipertónica de actividad de agua (aw) inferior a la del mismo (Genina, 2002), lo que establece un flujo de agua desde el alimento a la solución y un flujo de soluto en sentido contrario. El objetivo del presente trabajo fue investigar los diferentes efectos de los solutos, glucosa, sacarosa y jarabe de maíz de alta fructosa (JMAF) en la deshidratación osmótica de membrillo (Cydonia Vulgaris).Para ello se analizó comparativamente la evolución de la concentración de sólidos solubles de la fruta, el peso de la fruta y la concentración de la solución osmótica con respecto a tiempo y temperatura del proceso y cambio en la concentración de la solución osmótica. Se planteó un Diseño Multifactorial Categórico con 864 ensayos.El análisis de varianza indica que el tiempo y la Concentración de Solución Osmótica tienen efecto significativo en las repuestas en un 95% de nivel de confianza para los tres solutos ensayados, no así para la temperatura con valor p >0.05 para todas las respuestas. Se obtuvo mejor resultado en la DO utilizando Glucosa. Se ha observado que la pérdida de peso de la fruta fue mayor en la tratada con Glucosa teniendo un valor medio de 6,27 %, superior en pérdida de peso a la solución osmótica (SO) de Sacarosa y JMAF, además la fruta tratada con glucosa tuvo un mayor aumento en la concentración de la fruta llegando a 19.71°Brix (valor medio) indicando mayor pérdida de peso que con sacarosa y JMAF.Osmotic effect comparison of different solutes in quince pulp.AbstractOsmotic dehydration (OD) is the immersion of a food in a solution of water activity (aw) less than yours, which establishes a flow of water from the food to the solution and solute flow in the opposite direction. The aim of this study was to investigate the various effects of solutes, glucose, sucrose syrup, high fructose corn (HFCS) in the osmotic dehydration in Quince (Cydonia vulgaris). To this end we analyzed comparatively the evolution of the composition, mass and volume of the samples during the process and the kinetics involved in it. Multifactorial design was used a categorical with 864 runs.The variance analysis indicates that the time and osmotic solution concentration (CSO) have significant effect on all responses by 95% confidence level for the three solutes tested, but not for the temperature with p-value> 0.05 for all the answers.Best result was obtained in osmotic dehydration using as SO Glucose, Sucrose and HFCS that. It has been observed that the loss of fruit weight was higher in glucose treated having an average value of 6,26 percent, higher weight loss osmotic solution (SO). Sucrose and HFCS, as well as glucose-treated fruit had a greater increase concentration of 19,709 ° Brix (average) indicating greater loss of weigth.Key words: Quince; Dehydration; Solute; Osmosi

    The GAPS programme at TNG XXII. The GIARPS view of the extended helium atmosphere of HD189733 b accounting for stellar activity

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    Exoplanets orbiting very close to their host star are strongly irradiated. This can lead the upper atmospheric layers to expand and evaporate into space. The metastable helium (HeI) triplet at 1083.3nm has recently been shown to be a powerful diagnostic to probe extended and escaping exoplanetary atmosphere. We perform high-resolution transmission spectroscopy of the transiting hot Jupiter HD189733b with the GIARPS (GIANO-B + HARPS-N) observing mode of the Telescopio Nazionale Galileo, taking advantage of the simultaneous optical+near infrared spectral coverage to detect HeI in the planet's extended atmosphere and to gauge the impact of stellar magnetic activity on the planetary absorption signal. Observations were performed during five transit events of HD189733b. By comparison of the in- and out-of-transit GIANO-B observations we compute high-resolution transmission spectra, on which we perform equivalent width measurements and light-curves analyses to gauge the excess in-transit absorption in the HeI triplet. We detect an absorption signal during all five transits. The mean in-transit absorption depth amounts to 0.75+/-0.03%. We detect night-to-night variations in the HeI absorption signal likely due to the transit events occurring in presence of stellar surface inhomogeneities. We evaluate the impact of stellar-activity pseudo-signals on the true planetary absorption using a comparative analysis of the HeI and the Hα\alpha lines. We interpret the time-series of the HeI absorption lines in the three nights not affected by stellar contamination -exhibiting a mean in-transit absorption depth of 0.77+/-0.04%- using a 3-d atmospheric code. Our simulations suggest that the helium layers only fill part of the Roche lobe. Observations can be explained with a thermosphere heated to \sim12000 K, expanding up to \sim1.2 planetary radii, and losing \sim1 g/s of metastable helium.Comment: 17 pages, 17 figures, accepted for publication in A&

    Effects Of Length, Complexity, And Grammatical Correctness On Stuttering In Spanish-Speaking Preschool Children

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    Purpose: To explore the effects of utterance length, syntactic complexity, and grammatical correctness on stuttering in the spontaneous speech of young, monolingual Spanish-speaking children. Method: Spontaneous speech samples of 11 monolingual Spanish-speaking children who stuttered, ages 35 to 70 months, were examined. Mean number of syllables, total number of clauses, utterance complexity (i.e., containing no clauses, simple clauses, or subordinate and/or conjoined clauses), and grammatical correctness (i.e., the presence or absence of morphological and syntactical errors) in stuttered and fluent utterances were compared. Results: Findings revealed that stuttered utterances in Spanish tended to be longer and more often grammatically incorrect, and contain more clauses, including more subordinate and/or conjoined clauses. However, when controlling for the interrelatedness of syllable number and clause number and complexity, only utterance length and grammatical incorrectness were significant predictors of stuttering in the spontaneous speech of these Spanish-speaking children. Use of complex utterances did not appear to contribute to the prediction of stuttering when controlling for utterance length. Conclusions: Results from the present study were consistent with many earlier reports of English-speaking children. Both length and grammatical factors appear to affect stuttering in Spanish-speaking children. Grammatical errors, however, served as the greatest predictor of stuttering.Communication Sciences and Disorder
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