1,366 research outputs found

    Synthesis of hybrid automata with affine dynamics from time-series data

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    Formal design of embedded and cyber-physical systems relies on mathematical modeling. In this paper, we consider the model class of hybrid automata whose dynamics are defined by affine differential equations. Given a set of time-series data, we present an algorithmic approach to synthesize a hybrid automaton exhibiting behavior that is close to the data, up to a specified precision, and changes in synchrony with the data. A fundamental problem in our synthesis algorithm is to check membership of a time series in a hybrid automaton. Our solution integrates reachability and optimization techniques for affine dynamical systems to obtain both a sufficient and a necessary condition for membership, combined in a refinement framework. The algorithm processes one time series at a time and hence can be interrupted, provide an intermediate result, and be resumed. We report experimental results demonstrating the applicability of our synthesis approach

    Forming Early-type Galaxies in Groups Prior to Cluster Assembly

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    We study a unique proto-cluster of galaxies, the supergroup SG1120-1202. We quantify the degree to which morphological transformation of cluster galaxies occurs prior to cluster assembly in order to explain the observed early-type fractions in galaxy clusters at z=0. SG1120-1202 at z~0.37 is comprised of four gravitationally bound groups that are expected to coalesce into a single cluster by z=0. Using HST ACS observations, we compare the morphological fractions of the supergroup galaxies to those found in a range of environments. We find that the morphological fractions of early-type galaxies (~60 %) and the ratio of S0 to elliptical galaxies (0.5) in SG1120-1202 are very similar to clusters at comparable redshift, consistent with pre-processing in the group environment playing the dominant role in establishing the observed early-type fraction in galaxy clusters.Comment: 5 pages, 2 figures, 2 tables. Accepted for publication in ApJ Letter

    Aristonectes quiriquinensis, sp. nov., a new highly derived elasmosaurid from the upper Maastrichtian of central Chile

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    This paper describes a new species of elasmosaurid plesiosaur, Aristonectes quiriquinensis, sp. nov., based on a partial skeleton recovered from upper Maastrichtian beds of the Quiriquina Formation of central Chile. The material described here consists of two skeletons, one collected near the village of Cocholgue, and a second juvenile specimen from Quiriquina Island. Prior to these finds, Aristonectes was viewed as a monospecific genus, including only the enigmatic Aristonectes parvidens, the holotype of which consists of an incomplete skull and incomplete postcranium. Other material referred to the genus includes an incomplete juvenile skull and other postcranial material from the upper Maastrichtian of Antarctica, as well as a partial skull from the Quiriquina Formation of central Chile. The relationships of Aristonectes have been controversial, with competing theories assigning the genus to Cryptoclididae, Elasmosauridae, and Aristonectidae; however, there is a developing consensus that Aristonectes is a derived elasmosaurid, and this paper gives strong evidence for this view. Comparison of the specimen here studied with the holotype of A. parvidens demonstrates that A. quiriquinensis is a distinct species. The completeness of the adult skeleton allows the first confident size estimates for adult Aristonectes. It is a large plesiosaurian with a relatively large skull with numerous homodont teeth, a moderately long and laterally compressed neck, and relatively narrow trunk, with slender and elongate forelimbs. The two specimens are restricted to the upper Maastrichtian of central Chile, posing questions concerning the austral circumpolar distribution of different elasmosaurids towards the end of the Cretaceous.Fil: Otero, Rodrigo A.. Universidad de Chile; ChileFil: Soto Acuña, Sergio. Museo Nacional de Historia Natural de Santiago; Chile. Universidad de Chile; ChileFil: O'Keefe, Frank Robin. Marshall University; Estados UnidosFil: O'gorman, Jose Patricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleontología Vertebrados; ArgentinaFil: Stinnesbeck, Wolfgang. Heidelberg University; AlemaniaFil: Suárez, Mario E.. Museo Nacional de Historia Natural de Santiago; Chile. Universidad de Chile; ChileFil: Rubilar-Rogers, David. Museo Nacional de Historia Natural de Santiago; Chile. Universidad de Chile; ChileFil: Salazar, Christian. Museo Nacional de Historia Natural de Santiago; Chile. Universidad de Chile; ChileFil: Quinzio Sinn, Luis Arturo. Universidad de Concepción; Chil

    Expression of MICA, MICB and NKG2D in human leukemic myelomonocytic and cervical cancer cells

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    <p>Abstract</p> <p>Background</p> <p>Cancer cells are known to secrete the stress molecules MICA and MICB that activate cytotoxicity by lymphocytes and NK cells through their NKG2D receptor as a mechanism of immunological defense. This work was undertaken to evaluate if cancer cells can also express this receptor as a possible mechanisms of depletion of MIC molecules and thus interfere with their immune recognition.</p> <p>Methods</p> <p>Myelomonocytic leukemic (TPH-1 and U-937) and cervical cancer (CALO and INBL) cell lines were evaluated by Western Blot, ELISA, flow cytometry and immunocytochemistry to evaluate their capacity to express and secrete MICA and MICB and to be induced to proliferate by these molecules as well as to express their receptor NKG2D. Statistical analysis was performed by two-way ANOVA for time course analysis and Student's t-test for comparison between groups. Values were considered significantly different if p < 0.05.</p> <p>Results</p> <p>THP-1 and U-937 produce and secrete the stress MICA and MICB as shown by Western Blot of lysed cells and by ELISA of their conditioned media. By Western Blot and flow cytometry we found that these cells also express the receptor NKG2D. When THP-1 and U-937 were cultured with recombinant MICA and MICB they exhibited a dose dependent induction for their proliferation. CALO and INBL also produce MICA and MICB and were induced to proliferate by these stress molecules. By Western Blot, flow cytometry and immunocytochemistry we also found that these cells express NKG2D.</p> <p>Conclusions</p> <p>Our novel results that tumor cells can simultaneously secrete MIC molecules and express their receptor, and to be induced for proliferation by these stress molecules, and that tumor epithelial cells can also express the NKG2D receptor that was thought to be exclusive of NK and cytotoxic lymphocytes is discussed as a possible mechanism of immunological escape and of tumor growth induction.</p

    Desarrollo de un modelo de perfil de copa para Pinus cooperi Blanco en la UMAFOR 1008, Durango, México

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    A crown profile model for Pinus cooperi Blanco in UMAFOR 1008 (El Salto, Pueblo Nuevo, Durango) was developed from data corresponding to 92 sampled trees. Trees with well-formed crowns were selected from stands varying in age, density and site quality. Diameter at breast height, total height, crown width, crown length, and crown profile were measured in each tree. To predict the crown profile, basic geometric shapes and several mathematic models were evaluated. The model developed by Hann (1999) best described the experimental data of the total crown, light crown, and shaded crown, accounting for over 92 % of the observed variability.Se desarrolló un modelo de perfil de copa para Pinus cooperi Blanco a partir de 92 árboles en la UMAFOR 1008 (Región El Salto, Pueblo Nuevo, Durango). Se seleccionaron individuos con una copa bien conformada y de diferente edad, densidad y calidad de estación. En cada uno de los individuos se midieron las variables diámetro normal, altura total, diámetro, longitud y perfil de copa. Tanto formas geométricas sencillas como algunos modelos matemáticos se analizaron para predecir el perfil de la copa. El mejor modelo para describir el perfil de copa de P. cooperi fue el de Hann (1999), ya que tuvo mejor ajuste para la copa entera, copa de luz y copa de sombra, explicando más de 92 % de la variabilidad de los datos.S

    Relationship between the isometric force of the dominant hand and the Body Mass Index of university students

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    INTRODUCTION: Strength is the neuromuscular capacity to overcome or counter resistances through muscular activity and is closely linked to all the motor actions that the human being develops, and to his body mass index. OBJECTIVE: To determine the level of correlation between body mass index (BMI) and the isometric strength of the dominant hand of university students. METHOD: The strength was evaluated with a TAKEI SCIENTIFIC INSTRUMENT 5401 dynamometer to 70 university students using a random sampling method using a descriptive transactional design. We obtained data that were processed with a bivariate correlation obtaining the Pearson coefficient. We used SPSS ver. 15. RESULTS: The studied age was 23 ± 1.9 years, with a length of 165.6 cm. ± 7.72 for women and 173.7 cm. ± 7.95 men, as well as a weight in women of 64.1 ± 14.82 kg and men 82.3 ± 14.72 kg, which results in a BMI for women of 25.01 ± 4.405 m2/kg and 25.06 with ± 4.398 m2/kg for men. On the other hand, the female isometry strength was 3.08. ± 0.613 Kg and for men was 3.68 ± 0.839 Kg. In females, there was not correlation between the BMI and isometric strength (Sig = .192). Contrary, in males, there was a significant and negative correlation grade between the BMI and isometric strength (r = -0,452; Sig. = 0.035). CONCLUSIONS: In this study, it was observed that as BMI increases, strength does not grow. Therefore, other variables should be evaluated to understand what is related to the overweight or obesity of students

    Blanco DECam Bulge Survey (BDBS) IV: Metallicity Distributions and Bulge Structure from 2.6 Million Red Clump Stars

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    We present photometric metallicity measurements for a sample of 2.6 million bulge red clump stars extracted from the Blanco DECam Bulge Survey (BDBS). Similar to previous studies, we find that the bulge exhibits a strong vertical metallicity gradient, and that at least two peaks in the metallicity distribution functions appear at b < -5. We can discern a metal-poor ([Fe/H] ~ -0.3) and metal-rich ([Fe/H] ~ +0.2) abundance distribution that each show clear systematic trends with latitude, and may be best understood by changes in the bulge's star formation/enrichment processes. Both groups exhibit asymmetric tails, and as a result we argue that the proximity of a star to either peak in [Fe/H] space is not necessarily an affirmation of group membership. The metal-poor peak shifts to lower [Fe/H] values at larger distances from the plane while the metal-rich tail truncates. Close to the plane, the metal-rich tail appears broader along the minor axis than in off-axis fields. We also posit that the bulge has two metal-poor populations -- one that belongs to the metal-poor tail of the low latitude and predominantly metal-rich group, and another belonging to the metal-poor group that dominates in the outer bulge. We detect the X-shape structure in fields with |Z| > 0.7 kpc and for stars with [Fe/H] > -0.5. Stars with [Fe/H] < -0.5 may form a spheroidal or "thick bar" distribution while those with [Fe/H] > -0.1 are strongly concentrated near the plane.Comment: 26 pages, 22 figures, accepted for publication in MNRAS; the full data table is very long so only a stub table has been provided here; the full electronic table will be provided through MNRAS upon publication, but early access to the full table will be granted upon request to the author

    The Milky Way Bulge extra-tidal star survey: BH 261 (AL 3)

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    The Milky Way Bulge extra-tidal star survey (MWBest) is a spectroscopic survey with the goal of identifying stripped globular cluster stars from inner Galaxy clusters. In this way, an indication of the fraction of metal-poor bulge stars that originated from globular clusters can be determined. We observed and analyzed stars in and around BH 261, an understudied globular cluster in the bulge. From seven giants within the tidal radius of the cluster, we measured an average heliocentric radial velocity of = -61 +- 2.6 km/s with a radial velocity dispersion of \sigma = 6.1 +- 1.9 km/s. The large velocity dispersion may have arisen from tidal heating in the cluster's orbit about the Galactic center, or because BH 261 has a high dynamical mass as well as a high mass-to-light ratio. From spectra of five giants, we measure an average metallicity of = -1.1 +- 0.2 dex. We also spectroscopically confirm an RR Lyrae star in BH 261, which yields a distance to the cluster of 7.1 +- 0.4~kpc. Stars with 3D velocities and metallicities consistent with BH 261 reaching to ~0.5 degrees from the cluster are identified. A handful of these stars are also consistent with the spatial distribution of that potential debris from models focussing on the most recent disruption of the cluster.Comment: accepted for publication in The Astronomical Journa

    The karst site of Las Palomas (Guadalteba County, Málaga, Spain): A preliminary study of its MiddleeLate Pleistocene archaeopaleontological record

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    Cleaning works in the cave of Las Palomas in Teba (Málaga, Spain), developed by the Guadalteba Consortium, have provided a number of lithic tools and knapping products that may be ascribed to the Mode III technotypological tradition as well as remains of a number of large mammal species typical of MiddleeLate Pleistocene times. Topographic measurements help to place this ancient cave within a karst landform. This discovery opens up new perspectives in the research on the Neanderthal groups that inhabited the valleys of Guadalteba and Turón rivers in the middle basin of the Guadalhorce River, and thus in the southern region of the Iberian Peninsula
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