Generic ordering of structural transitions in quasi-one-dimensional Wigner crystals

We investigate the dependence of the structural phase transitions in an infinite quasi-one-dimensional system of repulsively interacting particles on the profile of the confining channel. Three different functional expressions for the confinement potential related to real experimental systems are used that can be tuned continuously from a parabolic to a hard-wall potential in order to find a thorough understanding of the ordering of the chain-like structure transitions. We resolve the longstanding issue why the most theories predicted a 1-2-4-3-4 sequence of chain configurations with increasing density, while some experiments found the 1-2-3-4 sequence.Comment: 7 pages, 5 figure

Modelos de control quimioterapéutico contra Fasciola hepatica en ganado bovino en pastoreo en clima cálido húmedo

2 páginas.-- Trabajo presentado al XIII Congreso Latinoamericano de Parasitología ( La Habana, Cuba, 11 al 23 de Noviembre, 1997).La fasciolosis en bovinos en el estado de Veracruz, México, tiene una alta prevalencia, por lo que se considera una necesidad generar información sobre modelos de control. Con el objetivo de evaluar 3 modelos de tratamientos fasciolicidas aplicados de manera estratégica en base a las condiciones climatológicas locales, se emplearon 3 grupos de 23 vacunos cada uno, hembras cruces de cebú con suizo pardo, homogéneos en las cantidades de huevos de 5 g de heces. Se utilizó el triclabendazol a dosis de 12 mg/kg. El grupo 1 fue tratado en enero, el 2 en enero y junio, y el 3 en enero, junio y octubre. Cada 45 días se les practicaron exámenes coprológicos cuantitativos (hpg) por la técnica de sedimentación durante un año. Los bovinos se encontraban localizados en una finca situada en el municipio de Nautla, Estado de Veracruz. Se encontró en el grupo 1 la prevalencia al inicio de 100%, en los siguientes 5 muestreos fue de 21.7 a 91.3 % y en el resto de 100%, mientras que el x de hpg al inicio fue de 13.23.14 se redujo en 5 muestreos de 0.560.26 a 12.12.02 mientras que en 4 se incrementó de 14.63.87 a 21.1 3.06 con diferencia (P0.01) entre el primer muestreo y los siguientes. En el grupo 2 la prevalencia al inicio fue de 100%, posteriormente se redujo en 8 muestreos de 8.6% a 95.6%, mientras que el último muestreo fue de 100%, el x de hpg al inicio fue de 15.043.62 se redujo en 8 muestreos de 0.170.13 a 14.102.13 mientras que el penúltimo muestreo fue de 15.733.07 con diferencia entre el primer muestreo hasta el 8, pero sin diferencia con el 9 y el 10 (P0.01). En el grupo 3 la prevalencia al inicio fue de 100% en los siguientes muestreos se redujo de 15.07% a 94.4%, mientras el x de hpg al inicio fue de 13.132.24 disminuyó en los subsecuentes muestreos 0.270.13 a 11.554.56 se encontró que hubo diferencia entre el primer muestreo con todos los subsecuentes (P0.01). Al comparar entre grupos mediante la prueba de Kruskall-Wallis se encontró que hay diferencia (P0.01) del muestreo 8 al 10.Peer reviewe

Stable Isotope Analysis of the Inca Mummy from Nevado de Chuscha (Salta, Argentina)

This paper presents the carbon (13C/12C), nitrogen (15N/14N), oxygen (18O/16O), hydrogen (2H/1H) and sulfur (34S/32S) stable isotope values measured in the hair of a female individual from north-western Argentina. The analysis of segments of this tissue allows for the recording of the diet and migratory changes with a short time resolution. The sample is from a mummified young female individual discovered in Chuscha mount, Salta province. It was found at more than 5000 masl, in a mountain sanctuary of the Inca expansion (capacochas). The paper discusses the paleodiet and mobility patterns of this individual in the period before her death, focusing on the isotopic variations in a limited time scale. The results indicate that the individual moved from a different region to the place where she was sacrificed. Furthermore, in the last year the individual was alive, a shift in the isotopic composition of the food consumed is detected: a variation in the importance of C4 over C3 resources is evident. The results are compared with the isotopic estimations for other children and young people recovered in archaeological contexts associated with capacochas to infer variability in the geographical trajectories covered during their last months of life.Fil: Killian Galván, Violeta Anahí. Universidad de Buenos Aires. Facultad de Filosofía y Letras. Instituto Interdisciplinario Tilcara; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Tessone, Augusto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geocronología y Geología Isotópica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geocronología y Geología Isotópica; ArgentinaFil: Valenzuela, Luciano Oscar. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Sociales. Departamento de Arqueología. Laboratorio de Ecología Evolutiva Humana (Sede Quequén); Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sharp, Z. D.. Universidad de Nuevo México.; Estados UnidosFil: Panarello, Hector Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geocronología y Geología Isotópica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geocronología y Geología Isotópica; Argentin

NAUTILUS-DTU10 MW Floating Offshore Wind Turbine at Gulf of Maine: Public numerical models of an actively ballasted semisubmersible

This study presents two numerical multiphysics models of the NAUTILUS-10 floating support structure mounting the DTU10 MW Reference Wind Turbine at Gulf of Maine site, and analyses its dynamics. With the site conditions and the FAST model of the onshore turbine as the starting point, the floating support structure: tower, floating substructure with its corresponding active ballast system and station keeping system, was designed by NAUTILUS. The numerical models were developed and the onshore DTU wind energy controller was tuned to avoid the resonance of the operating FOWT by TECNALIA, in the framework of H2020 LIFES50+ project. This concept and its subsystems are fully characterised throughout this paper and implemented in opensource code, FAST v8.16. Here, the mooring dynamics are solved using MoorDyn, and the hydrodynamic properties are computed using HydroDyn. Viscous effects, not captured by radiation-diffraction theory, are modelled using two different approaches: (1) through linear and quadratic additional hydrodynamic damping matrices and (2) by means of Morison elements. A set of simulations (such as, decay, wind only and broadband irregular waves tests) were carried out with system identification purposes and to analyse the differences between the two models presented. Then, a set of simulations in stochastic wind and waves were carried out to characterise the global response of the FOWT.European Union Horizon2020 programme under the agreement H2020-LCE-2014-1-640741, LIFES50+ projec

New stopping criteria for segmenting DNA sequences

We propose a solution on the stopping criterion in segmenting inhomogeneous DNA sequences with complex statistical patterns. This new stopping criterion is based on Bayesian Information Criterion (BIC) in the model selection framework. When this stopping criterion is applied to a left telomere sequence of yeast Saccharomyces cerevisiae and the complete genome sequence of bacterium Escherichia coli, borders of biologically meaningful units were identified (e.g. subtelomeric units, replication origin, and replication terminus), and a more reasonable number of domains was obtained. We also introduce a measure called segmentation strength which can be used to control the delineation of large domains. The relationship between the average domain size and the threshold of segmentation strength is determined for several genome sequences.Comment: 4 pages, 4 figures, Physical Review Letters, to appea

Heuristic Segmentation of a Nonstationary Time Series

Many phenomena, both natural and human-influenced, give rise to signals whose statistical properties change under time translation, i.e., are nonstationary. For some practical purposes, a nonstationary time series can be seen as a concatenation of stationary segments. Using a segmentation algorithm, it has been reported that for heart beat data and Internet traffic fluctuations--the distribution of durations of these stationary segments decays with a power law tail. A potential technical difficulty that has not been thoroughly investigated is that a nonstationary time series with a (scale-free) power law distribution of stationary segments is harder to segment than other nonstationary time series because of the wider range of possible segment sizes. Here, we investigate the validity of a heuristic segmentation algorithm recently proposed by Bernaola-Galvan et al. by systematically analyzing surrogate time series with different statistical properties. We find that if a given nonstationary time series has stationary periods whose size is distributed as a power law, the algorithm can split the time series into a set of stationary segments with the correct statistical properties. We also find that the estimated power law exponent of the distribution of stationary-segment sizes is affected by (i) the minimum segment size, and (ii) the ratio of the standard deviation of the mean values of the segments, and the standard deviation of the fluctuations within a segment. Furthermore, we determine that the performance of the algorithm is generally not affected by uncorrelated noise spikes or by weak long-range temporal correlations of the fluctuations within segments.Comment: 23 pages, 14 figure

Hydrodynamic identification of NAUTILUS FOWT platform from small scale tests

A small-scale tank test campaign of the NAUTILUS offshore wind floating semisub-mersible platform was held at the Ifremer Deep Water Basin within the framework of the MaRINET 2 project. The support structure consists in four stabilized columns on a square pontoon supporting a generic 8-MW wind turbine. The tests were carried out at 1:36 Froude scale in parked conditions, and the mooring system was modelled as a set of aerial mooring springs providing a nonlinear stiffness. The hydrodynamic characterization of the floater from experimental data was tackled by using traditional techniques in naval architecture), as well as approaches derived from operational modal analysis in the frequency domain, such as the Sub Space Identification—Covariance (SSI-COV) method. The validity of this approach and its potential application to the identification of such kind of structures is discussed against the results of a more traditional technique based on the fitting of decay tests

Toksičnost talija u humanoj populaciji

Thallium is a naturally occurring trace element, widely distributed in the earth’s crust, but at very low concentrations. It does not have a known biological use and does not appear to be an essential element for life. It has been considered one of the most toxic heavy metals. Occasionally, there are reports on thallium poisoning as results of suicide or murder attempt or accident. The main threat to humans is through occupational exposure, environmental contamination, and accumulation in food, mainly in vegetables grown on contaminated soil. Increasing use in emerging new technologies and demanding high-tech industry constantly raise concern about exposure risk to all living organisms. Thallium is considered a cumulative poison that can cause adverse health effects and degenerative changes in many organs. The effects are the most severe in the nervous system. The exact mechanism of thallium toxicity still remains unknown, although impaired glutathione metabolism, oxidative stress, and disruption of potassium-regulated homeostasis may play a role. The lack of data about mutagenic, carcinogenic, or teratogenic effects of thallium compounds in humans calls for further research.Talij je u prirodi široko rasprostranjen teški metal, prisutan u vrlo niskim koncentracijama pa ga stoga ubrajamo u elemente u tragovima. Budući da organizmima nije potreban ni u jednoj razvojnoj fazi, ne ubrajamo ga u grupu esencijalnih elemenata. Talij zbog njegovih svojstava ubrajamo među najtoksičnije teške metale. Povremeno se još uvijek pojavljuju slučajevi u kojima je talij upotrijebljen kao sredstvo za pokušaj ubojstva, odnosno samoubojstva, ali i slučajevi nenamjernog, slučajnog trovanja talijem. U današnje vrijeme potencijalna o asnost od trovanja talijem postoji zbog profesionalne izloženosti, izbijanja ekološke katastrofe ili zbog akumulacije u hranidbenim lancima, uglavnom zbog uzgoja hrane na onečišćenom tlu. Sve češća uporaba talija u visokotehnološkoj industriji kao odgovor na zahtjeve moderne tehnologije neprestano povećava rizik od izloženosti svih živih organizama štetnim utjecajima talija u okolišu. Talij ima izuzetno negativan učinak na različite organske sustave, a osobito na živčani sustav. Mehanizmi toksičnosti talija još uvijek nisu u potpunosti razjašnjeni, premda važnu ulogu imaju poremećaji metabolizma glutationa, oksidativni stres i narušavanje homeostaze posredovane ionima kalija. Nedostatak podataka o mutagenim, kancerogenim ili teratogenim učincima talija i njegovih spojeva u ljudi opravdava buduća istraživanja ovog vrlo toksičnog metala