7,716 research outputs found

    Optical observations of very low ionization HII regions in the large Magellanic cloud

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    Several very low ionization isolated HII regions were detected on a prism-objective plate of the Large Magellanic Cloud. Most of the objects show a very weak (OIII) lambda 5007 emission line and, on the other hand the (OII) lambda 6584 doublets are very intense. This kind of objects seem to be ideal in order to determine accurate N and O abundance, avoiding the use of large ionization correction factors in the N abundance determination. Spectrophotometric observations of these regions were carried out with the 4 m telescope and the 2-D Frutti spectrograph at Cerro Tololo, and with the 1.52 m and the Image Dissector Scanner (IDS) at La Silla, ESO. The wavelength range lambda lambda 3700 to 7000 A was covered. Calibrated fluxes of the emission lines detected were measured, and from these data preliminary results of physical conditions of the gas as well as some ionic abundances were derived. Comparisons of the observations with ionization structure models show that the effective temperatures of the ionizing stars are less than 35,000 K. Possible abundances gradients across the large megallanic cloud are discussed

    Nesting Success of Kemp’s Ridley Sea Turtles, Lepidochelys kempi, at Rancho Nuevo, Tamaulipas, Mexico, 1982–2004

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    The Kemp’s ridley sea turtle, Lepidochelys kempi, was on the edge of extinction owing to a combination of intense egg harvesting and incidental capture in commercial fishing trawls. Results from a cooperative conservation strategy initiated in 1978 between Mexico and the United States to protect and restore the Kemp’s ridley turtle at the main nesting beach at Rancho Nuevo, Tamaulipas, Mexico are assessed. This strategy appears to be working as there are signs that the species is starting to make a recovery. Recovery indicators include: 1) increased numbers of nesting turtles, 2) increased numbers of 100+ turtle nesting aggregations (arribadas), 3) an expanding nesting season now extending from March to August, and 4) significant nighttime nesting since 2003. The population low point at Rancho Nuevo was in 1985 (706 nests) and the population began to significantly increase in 1997 (1,514 nests), growing to over 4,000 nests in 2004. The size and numbers of arribadas have increased each year since 1983 but have yet to exceed the 1,000+ mark; most arribadas are still 200–800+ turtles

    On the variability of HD 170699 - a possible COROT target

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    We present the analysis of the variability of HD 170699, a COROT star showing the characteristics of a non evolutionary Delta Scuti star with high rotational velocity. There is a clear period of 10.45 c/d with 5.29 mmag amplitude in the y filter. From the data, it can be seen that the star shows multi-periodicity and it is necessary to add more frequencies to adjust the observationsComment: To appear in RevMexAA(SC) in Proceedings of XII Reunion Regional Latinoamericana de la UAI held in Isla Margarita, Venezuela, October 22-26, 200

    Late presentation of human T-lymphotropic virus type 1 infection in Spain reflects suboptimal testing strategies

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    Diagnosis; Myelopathy; Sexually transmitted infectionsDiagnóstico; Mielopatía; Infecciones de transmisión sexualDiagnòstic; Mielopatia; Infeccions de transmissió sexualObjectives Although only 10% of persons infected with human T-lymphotropic virus type 1 (HTLV-1) may develop virus-associated illnesses over their lifetime, missing the earlier diagnosis of asymptomatic carriers frequently leads to late presentation. Methods A nationwide HTLV-1 register was created in Spain in 1989. We examined the main demographics and clinical features at the time of the first diagnosis for more than three decades. Results A total of 428 individuals infected with HTLV-1 had been reported in Spain until the end of 2021. Up to 96 (22%) individuals presented clinically with HTLV-1-associated conditions, including subacute myelopathy (57%), T-cell lymphoma (34%), or Strongyloides stercoralis infestation (8%). Since 2008, HTLV-1 diagnosis has been made at blood banks (44%) or clinics (56%). Native Spaniards and Sub-Saharan Africans are overrepresented among patients presenting with HTLV-1-associated illnesses suggesting that poor epidemiological and/or clinical suspicion, which led to the late presentation are more frequent in them than carriers from Latin America (LATAM) (31.7% vs 20.4%, respectively; P = 0.015). Conclusion HTLV-1 infection in Spain is frequently diagnosed in patients presenting with characteristic illnesses. Although screening in blood banks mostly identifies asymptomatic carriers from LATAM, a disproportionately high number of Spaniards and Africans are diagnosed too late at the time of clinical manifestations. Expanding testing to all pregnant women and clinics for sexually transmitted infections could help to unveil HTLV-1 asymptomatic carriers.This work was supported in part by grants from FIS-ISCIII PI-21/1717 and Fundación Mutua Madrileña AP-174112020

    Stereo Vision Matching using Characteristics Vectors

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    Stereo vision is a usual method to obtain depth information from images. The problems encountered when applying the majority of well established algorithms to provide this information are due to the high computational load required. This occurs in both the block matching and graphical cues (such as edges) matching. In this article we address this issue by performing an image analysis which considers each pixel only once, thus enhancing the efficiency of the image processing. Additionally, when matching is carried out over statistical descriptors of the image regions, commonly referred to as characteristic vectors, whose number of these vectors is, by definition, lower than the possible block matching possibilities, the algorithm achieves an improved level of performance. In this paper we present a new algorithm which has been specifically designed to solve the commonly observed problems which arise from other well know techniques. This algorithm was designed using a previous work carried out by the authors in this area to determine the descriptors extraction processes. The complete analysis has been carried out over gray scale images. The results obtained from both real and synthetic images are presented in terms of matching quality and time consumption and compared to other published results. Finally, a discussion is provided on additional features related to the matching process

    A Brief Review on the Regulatory Roles of MicroRNAs in Cystic Diseases and Their Use as Potential Biomarkers

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    miRNAs are small endogenous conserved non-coding RNA molecules that regulate post-transcriptional gene expression through mRNA degradation or translational inhibition, modulating nearly 60% of human genes. Cystic diseases are characterized by the presence of abnormal fluid-filled sacs in the body, and though most cysts are benign, they can grow inside tumors and turn malignant. Recent evidence has revealed that the aberrant expression of a number of miRNAs present in extracellular fluids, including plasma or serum, urine, saliva, follicular fluid, and semen, contribute to different cystic pathologies. This review aims to describe the role of different miRNAs in three worldwide relevant cystic diseases: polycystic ovarian syndrome (PCOS), polycystic kidney disease (PKD), and pancreatic cyst tumors (PCTs), as well as their potential use as novel biomarkers.publishedVersio

    Mechanochromic Luminescent Tetrathiazolylthiophenes: Evaluating the Role of Intermolecular Interactions through Pressure and Temperature-Dependent Raman Spectroscopy

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    The Raman spectrum of the mechanochromic luminescent tetrathiazolylthiophene has been investigated as a function of pressure and temperature. This study verifies the sensitivity of the Raman spectroscopy as a technique to characterize and understand the structural effects causing any mechanochromic changes. Continuous and evident Raman shifts and changes in intensities of the strongest lines in the spectra occur while increasing pressure or lowering temperature. These spectral changes are related to the modulation of intermolecular C–H···N hydrogen bonding previously identified for this system. The Raman bands involved are assigned to collective normal modes associated to the CC bond stretching of the rings and reveal that the modulation of local hydrogen bonding interaction has indeed an effect that has an impact on the whole conjugated structure of the molecule. Pressure-dependent Raman spectra have been also computed by means of periodic density functional theory calculations of the crystal, giving an accurate prediction of the experimental trends

    ANGPTL-4 is associated with obesity and lipid profile in children and adolescents

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    Angiopoietin-like protein 4 (ANGPTL-4) regulates lipidic metabolism and a_ects energy homeostasis. However, its function in children with obesity remains unknown. We investigated plasma ANGPTL-4 levels in children and its relationship with body mass index (BMI) and di_erent lipidic parameters such as free fatty acids (FFA). Plasma ANGPTL-4 levels were analyzed in two di_erent cohorts. In the first cohort (n = 150, age 3-17 years), which included children with normal weight or obesity, we performed a cross-sectional study. In the second cohort, which included only children with obesity (n = 20, age 5-18 years) followed up for two years after an intervention for weight loss, in which we performed a longitudinal study measuring ANGPTL-4 before and after BMI-loss. In the cross-sectional study, circulating ANGPTL-4 levels were lower in children with obesity than in those with normal weight. Moreover, ANGPTL-4 presented a negative correlation with BMI, waist circumference, weight, insulin, homeostasis model assessment of insulin resistance index (HOMA index), triglycerides, and leptin, and a positive correlation with FFA and vitamin-D. In the longitudinal study, the percent change in plasma ANGPTL-4 was correlated with the percent change in FFA, total-cholesterol and high-density lipoprotein cholesterol. This study reveals a significant association of ANGPTL-4 with pediatric obesity and plasma lipid profile
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