On central tendency and dispersion measures for intervals and hypercubes

The uncertainty or the variability of the data may be treated by considering, rather than a single value for each data, the interval of values in which it may fall. This paper studies the derivation of basic description statistics for interval-valued datasets. We propose a geometrical approach in the determination of summary statistics (central tendency and dispersion measures) for interval-valued variables

Computing Inferences for Large-Scale Continuous-Time Markov Chains by Combining Lumping with Imprecision

If the state space of a homogeneous continuous-time Markov chain is too large, making inferences - here limited to determining marginal or limit expectations - becomes computationally infeasible. Fortunately, the state space of such a chain is usually too detailed for the inferences we are interested in, in the sense that a less detailed - smaller - state space suffices to unambiguously formalise the inference. However, in general this so-called lumped state space inhibits computing exact inferences because the corresponding dynamics are unknown and/or intractable to obtain. We address this issue by considering an imprecise continuous-time Markov chain. In this way, we are able to provide guaranteed lower and upper bounds for the inferences of interest, without suffering from the curse of dimensionality.Comment: 9th International Conference on Soft Methods in Probability and Statistics (SMPS 2018

The European COST Action EUBrewNet: towards consistency in quality control, quality assurance and coordinated operations of the Brewer Instrument

Presentación realizada en: 10th meeting of the Ozone Research Managers (ORM) como parte de "Vienna Convention for the Protection of the Ozone Layer", celebrado en Ginebra (Suiza) del 28 al 30 de marzo de 2017

The Nuclear Yukawa Model on a Lattice

We present the results of the quantum field theory approach to nuclear Yukawa model obtained by standard lattice techniques. We have considered the simplest case of two identical fermions interacting via a scalar meson exchange. Calculations have been performed using Wilson fermions in the quenched approximation. We found the existence of a critical coupling constant above which the model cannot be numerically solved. The range of the accessible coupling constants is below the threshold value for producing two-body bound states. Two-body scattering lengths have been obtained and compared to the non relativistic results.Comment: 15 page

Aberrant DNA Methylation Reprogramming During Induced Pluripotent Stem Cell Generation is Dependent on the Choice of Reprogramming Factors

The conversion of somatic cells into pluripotent stem cells via overexpression of reprogramming factors involves epigenetic remodeling. DNA methylation at a significant proportion of CpG sites in induced pluripotent stem cells (iPSCs) differs from that of embryonic stem cells (ESCs). Whether different sets of reprogramming factors influence the type and extent of aberrant DNA methylation in iPSCs differently remains unknown. In order to help resolve this critical question, we generated human iPSCs from a common fibroblast cell source using either the Yamanaka factors (OCT4, SOX2, KLF4 and cMYC) or the Thomson factors (OCT4, SOX2, NANOG and LIN28), and determined their genome-wide DNA methylation profiles. In addition to shared DNA methylation aberrations present in all our iPSCs, we identified Yamanaka-iPSC (Y-iPSC)-specific and Thomson-iPSC (T-iPSC)-specific recurrent aberrations. Strikingly, not only were the genomic locations of the aberrations different but also their types: reprogramming with Yamanaka factors mainly resulted in failure to demethylate CpGs, whereas reprogramming with Thomson factors mainly resulted in failure to methylate CpGs. Differences in the level of transcripts encoding DNMT3b and TET3 between Y-iPSCs and T-iPSCs may contribute partially to the distinct types of aberrations. Finally, de novo aberrantly methylated genes in Y-iPSCs were enriched for NANOG targets that are also aberrantly methylated in some cancers. Our study thus reveals that the choice of reprogramming factors influences the amount, location, and class of DNA methylation aberrations in iPSCs. These findings may provide clues into how to produce human iPSCs with fewer DNA methylation abnormalities

Mortandad masiva de Mesodesma mactroides (Bivalvia: Mactracea) en el Partido de la costa, Buenos Aires, Argentina, en septiembre 2004

Massive mortality of Mesodesma mactroides (Bivalvia: Mactracea) in Partido de la Costa, Buenos Aires, Argentina in September 2004 Yellow clam Mesodesma mactroides has been decreased by several events of massive mortality along its distribution in Brazil, Uruguay and Argentina. This study evaluates and compares concentrations of As, Cd, Cr, Cu, Ni, Pb and Zn, in the tissues of clams collected during an event of massive mortality, in September 2004 and one year after. Quantification of heavy metals was realized by acid digestion and later determination by spectrometry. Values of Cd, Cu and Pb (11 ± 2, 42 ± 4 and 7 ± 1 mg/kg dry weight, respectively) in clam tissues during mortality event were higher than the ones registered one year later. Value of Cd in clams during the mortality (~1.5 mg/kg wet weight) was superior to the maximum limit of tolerance for the human consumption. Absence of Cd in sediments and seawater, suggests that the clams suffered a process of punctual and acute pollution. Mortality could have been the result of a set of factors that affected the subtidal population of yellow clam: climatic adverse conditions can "extracted" from the bottom and dragged to the beach the specimens, whose physiology was altered by an isolated event of pollution with heavy metals.La almeja amarilla Mesodesma mactroides ha sido diezmada por varios eventos de mortandad masiva a lo largo de su distribución en Brasil, Uruguay y Argentina. Este estudio evalúa y compara la concentración de As, Cd, Cr, Cu, Ni, Pb y Zn, en los tejidos de las almejas colectadas durante un evento de mortandad en Septiembre 2004 y un año después. La cuantificación de los metales se realizó por digestión ácida y posterior determinación por espectrometría. Los valores de Cd, Cu y Pb (11 ± 2, 42 ± 4 y 7 ± 1 mg/kg Peso Seco, respectivamente) en tejido de almeja fueron superiores a los registrados un año después. El valor de Cd en almejas durante la mortandad (~1.5 mg/kg Peso Fresco) es superior al límite máximo de tolerancia para el consumo humano. La ausencia de Cd en sedimentos y agua, sugiere que las almejas sufrieron un proceso de contaminación puntual y aguda. La mortandad pudo haber sido la resultante de un conjunto de factores que afectaron a la población submareal de almeja amarilla: condiciones climáticas adversas pueden haber "arrancado" del fondo submareal y arrastrado a la playa a los especimenes, cuya fisiología estaba alterada por un evento aislado de contaminación con metales pesados

The High Frequency Instrument of Planck: Requirements and Design

The Planck satellite is a project of the European Space Agency based on a wide international collaboration, including United States and Canadian laboratories. It is dedicated to the measurement of the anisotropy of the Cosmic Microwave Background (CMB) with unprecedented sensitivity and angular resolution. The detectors of its High frequency Instrument (HFI) are bolometers cooled down to 100 mK. Their sensitivity will be limited by the photon noise of the CMB itself at low frequencies, and of the instrument background at high frequencies. The requirements on the measurement chain are directly related to the strategy of observation used for the satellite. Due to the scanning on the sky, time features of the measurement chain are directly transformed into angular features in the sky maps. This impacts the bolometer design as well as other elements: For example, the cooling system must present outstanding temperature stability, and the amplification chain must show, down to very low frequencies, a flat noise spectrum

Polarization of the WMAP Point Sources

The detection of polarized sources in the WMAP 5-year data is a very difficult task. The maps are dominated by instrumental noise and only a handful of sources show up as clear peaks in the Q and U maps. Optimal linear filters applied at the position of known bright sources detect with a high level of significance a polarized flux P from many more sources, but estimates of P are liable to biases. Using a new technique, named the "filtered fusion technique", we have detected in polarization, with a significance level greater than 99.99% in at least one WMAP channel, 22 objects, 5 of which, however, do not have a plausible low radio frequency counterpart and are therefore doubtful. Estimated polarized fluxes P < 400 mJy at 23 GHz were found to be severely affected by the Eddington bias. The corresponding polarized flux limit for Planck/LFI at 30 GHz, obtained via realistic simulations, is 300 mJy. We have also obtained statistical estimates of, or upper limits to the mean polarization degrees of bright WMAP sources at 23, 33, 41, and 61 GHz, finding that they are of a few percent.Comment: 10 pages, 6 figures. Accepted for publication in Ap

Mapping the CMB Sky: The BOOMERANG experiment

We describe the BOOMERanG experiment, a stratospheric balloon telescope intended to measure the Cosmic Microwave Background anisotropy at angular scales between a few degrees and ten arcminutes. The experiment has been optimized for a long duration (7 to 14 days) flight circumnavigating Antarctica at the end of 1998. A test flight was performed on Aug.30, 1997 in Texas. The level of performance achieved in the test flight was satisfactory and compatible with the requirements for the long duration flight.Comment: 11 pages, 6 figure