696 research outputs found
Observation of a tricritical wedge filling transition in the 3D Ising model
In this Letter we present evidences of the occurrence of a tricritical
filling transition for an Ising model in a linear wedge. We perform Monte Carlo
simulations in a double wedge where antisymmetric fields act at the top and
bottom wedges, decorated with specific field acting only along the wegde axes.
A finite-size scaling analysis of these simulations shows a novel critical
phenomenon, which is distinct from the critical filling. We adapt to
tricritical filling the phenomenological theory which successfully was applied
to the finite-size analysis of the critical filling in this geometry, observing
good agreement between the simulations and the theoretical predictions for
tricritical filling.Comment: 5 pages, 3 figure
Phenological and molecular studies on the introduced seaweed Dictyota cyanoloma (Dictyotales, Phaeophyceae) along the Mediterranean coast of the Iberian Peninsula
Dictyota cyanoloma, a distinctive brown algal species characterized by a blue-iridescent margin, was recently reported as an introduced species in the Mediterranean Sea but little is known about its distribution dynamics, morphological plasticity and genetic structure. In this integrative study, we evaluate its past and present occurrence along the Mediterranean Iberian coast, assess the species' phenology in Palamos (Girona, Spain) and analyze the haplotype diversity by sequencing 49 individuals from nine sampling sites for different chloroplast and mitochondrial DNA regions. Although D. cyanoloma currently occurs along all the Mediterranean Iberian coasts (in 19 of 36 localities sampled, mostly in marinas and harbour environments), we were not able to find any herbarium material of this species (at BCN-Phyc and MA) predating the year 1987. In Palamos, D. cyanoloma is present all through the year, with a maximum development in winter and a minimum in summer. Fertile specimens are absent during summer (July and August). Sporophytes are dominant from January to June and gametophytes were found only in February, March and June. Information about the antheridia, which has never been described before, is provided. Two chloroplast and three mitochondrial haplotypes were observed, indicating that multiple introductions of D. cyanoloma occurred in the study area. Additionally, the genetic structure suggests that spread did not occur through simple advancing wave fronts but by several longdistance dispersal events. Further studies employing microsatellite markers could potentially offer a better resolution to unravel expansion and colonisation dynamics of D. cyanoloma in the Mediterranean Sea
Computer simulations of nematic drops: Coupling between drop shape and nematic order
We perform Monte Carlo computer simulations of nematic drops in equilibrium with their vapor
using a Gay-Berne interaction between the rod-like molecules. To generate the drops, we initially
perform NPT simulations close to the nematic-vapor coexistence region, allow the system to equilibrate
and subsequently induce a sudden volume expansion, followed with NVT simulations. The
resultant drops coexist with their vapor and are generally not spherical but elongated, have the rodlike
particles tangentially aligned at the surface and an overall nematic orientation along the main
axis of the drop. We find that the drop eccentricity increases with increasing molecular elongation,
κ. For small κ the nematic texture in the drop is bipolar with two surface defects, or boojums, maximizing
their distance along this same axis. For sufficiently high κ, the shape of the drop becomes
singular in the vicinity of the defects, and there is a crossover to an almost homogeneous texture; this
reflects a transition from a spheroidal to a spindle-like dro
La Termogènesi als calorÃmetres per conducció: caracterÃstiques dinà miques i possibilitats deconvolutives
Es descriuen les caracterÃstiques generals dels dispositius calorimètrics, les possibilitats de tractament
mitjançant models i els mètodes per aproximar-se a la termogènesi o dissipació instantà nia al si de la cèl•lula laboratori.
La descripció dinà mica es fa dins de l'espai freqüencial,
que permet introduir de manera natural diferents lÃmits
de freqüència segons les caracterÃstiques dels dispositius
i del procés que vol estudiar-se.
Per al tractament global dels calorÃmetres s'utilitza
una escala relativa de temps i de freqüència. Això permet
tractar sistemà ticament les condicions imposades per les
tècniques deconvolutives, l'aparellatge experimental i els
propis fenòmens fÃsics.General features of flow or conduction calorimeters are
briefly described together with several methods to obtain the thermogenesis or instantaneous power dissipated inside the laboratory cell. The possibi l ities of solvable models are also discussed. The dynamic behaviour of the calorimeter is readily described in frequency space, thus allowing the intrcduction of several frequential limits depending on the characteristics both of the device and of the phenomenon under study. A systematic treatment of conduction calorimeters may be attained if relative scales, i n time (t/τ1) and frequency
(θ τ1), are considered. Now, the efficiency of a given deconvolutive technique and the limits imposed by the experimental device itself or by the physical phenomena studied are easily evaluated
Lipidomics Reveals Reduced Inflammatory Lipid Species and Storage Lipids after Switching from EFV/FTC/TDF to RPV/FTC/TDF: A Randomized Open-Label Trial
HIV and antiretroviral therapy affect lipid metabolism. Lipidomics quantifies several individual species that are overlooked using conventional biochemical analyses, outperforming traditional risk equations. We aimed to compare the plasma lipidomic profile of HIV patients taking efavirenz (EFV) or rilpivirine (RPV). Patients >/= 18 years old on EFV co-formulated with emtricitabine and tenofovir disoproxil fumarate (FTC/TDF) with HIV-RNA /=6 months were randomized to continue EFV/FTC/TDF (n = 14) or switch to RPV/FTC/TDF (n =15). Lipidomic analyses conducted by mass spectrometry (MS) were performed at baseline and after 12 and 24 weeks. OWLiver((R)) Care and OWLiver((R)) tests were performed to estimate the presence of fatty liver disease (NAFLD). No significant differences (83% male, median age 44 years, 6 years receiving EFV/FTC/TDF, CD4(+) count 740 cells/mm(3), TC 207 [57 HDL-C/133 LDL-C] mg/dL, TG 117 mg/dL) were observed between the groups at baseline. Significant reductions in plasma lipids and lipoproteins but increased circulating bilirubin concentrations were observed in patients who switched to RPV/FTC/TDF. Patients on RPV/FTC/TDF showed a decrease in the global amount of storage lipids (-0.137 log2 [fold-change] EFV vs. 0.059 log2 [fold-change] RPV) but an increase in lysophosphatidylcholines (LPCs) and total steroids. Compared with EFV, RPV increased metabolites with anti-inflammatory properties and reduced the repository of specific lipotoxic lipids
Recommended from our members
Physical weathering of carbonate host-rock by precipitation of soluble salts in caves: A case study in El Orón-Arco Cave (Region of Murcia, SE Spain)
The dissolution of carbonate host-rock by freshwater in phreatic or vadose conditions is the most common mechanism for the formation of caves; however, circulation of saline solutions through carbonate materials and precipitation of soluble salts may also play an important role. We studied the stable isotope composition (δ18O and δ34S of sulfate, δ18O and δD of structurally-bound gypsum hydration water and 87Sr/86Sr) and salinity of fluid inclusions in gypsum speleothems found in El Orón-Arco Cave (Cartagena, SE Spain). We suggest that physical weathering of carbonate host-rock was driven by precipitation of soluble sea-salts (mostly gypsum and halite), and this process controlled the recent geomorphological evolution of the cave. The Triassic carbonate host-rock shows clear evidence for salt weathering, including gypsum/halite infillings in cracks of the bedrock, mechanical spalling of the carbonate, and detachment of rock fragments that lead to the formation cave voids and in-situ accumulations of piles of unsorted rubble. Sulfur and oxygen isotopes of gypsum sulfate (3.0‰ < δ18O < 11.6‰ and 16.7‰ < δ34S < 20.7‰) are generally lower than modern seawater sulfate and suggest contributions from a 34S-depleted source (i.e. oxidation of pyrite). The δ18O and δD of gypsum hydration water are relatively low compared to expected values for the evaporation of pure seawater to gypsum saturation, suggesting that gypsum precipitation involved a secondary calcium-sulfate source or recycling of gypsum from previous stages, along with mixing of seawater and meteoric water seepage to the cave. The 87Sr/86Sr in gypsum shows intermediate values between modern seawater and Triassic carbonate values because of interaction between the solution and the bedrock. The salinities of the speleothem-forming solutions are relatively high (13.2 ± 3.2 wt% eq. NaCl) compared to gypsum formed from evaporated brackish solutions (i.e. ~4–8 wt% eq. NaCl) and indicate dissolution of earlier evaporites before secondary gypsum precipitation. This cave-forming mechanism, which is related to saline water circulation and precipitation of evaporitic minerals, may be common in other coastal caves
Random mating and reproductive compatibility among Argentinean and southern Brazilian populations of Anastrepha fraterculus (Diptera: Tephritidae)
As a prerequisite for area-wide application of the sterile insect technique in an area encompassing northern Argentina and southern Brazil, prezygotic and postzygotic reproductive compatibility among three geographically distant populations in the area was tested. In field cages, sexually mature adults of each population were found to be sexually compatible, mating duration was not affected by fly origin and there was no clear evidence of spatial partition of mating location. In the laboratory, homotypic and heterotypic crosses for all possible combinations displayed similar levels of fertility and yielded F1 adults without distortion of the sex ratio. Finally, F1 hybrid and parental adults produced equally viable F2 eggs. Put together, our results and those from earlier studies suggest that a large area, ranging from Buenos Aires to the surroundings of São Paulo, could be managed using a single A. fraterculus mass-reared strain. At the northern margin of this area, two A. fraterculus morphotypes appear to coexist in sympatry. We delineate future research to further delimit the distribution of the aff1 morphotype (Argentina-southern Brazil) and to gain insight into evolutionary patterns producing divergence and radiation of tropical fruit fly species.Fil: Rull, J.. Instituto de EcologÃa; MéxicoFil: Abraham, Solana. Consejo Nacional de Investigaciones CientÃficas y Técnicas; Argentina. Universidad Nacional de Tucumán. Facultad de AgronomÃa y Zootecnia. Cátedra Terapéutica Vegetal; ArgentinaFil: Kovaleski, A.. Estação Experimental de Vacaria. Embrapa Uva e Vinho; Brasil. International Atomic Energy Agency; AustriaFil: Segura, Diego Fernando. Instituto Nacional de TecnologÃa Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de AgrobiotecnologÃa y BiologÃa Molecular. Grupo Vinculado Instituto de Genética "Ewald A. Favret" al Iabimo | Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de AgrobiotecnologÃa y BiologÃa Molecular. Grupo Vinculado Instituto de Genética "Ewald A. Favret" al Iabimo; ArgentinaFil: Islam, A.. International Atomic Energy Agency; AustriaFil: Wornoayporn, V.. International Atomic Energy Agency; AustriaFil: Dammalage, T.. International Atomic Energy Agency; AustriaFil: Tomas, U. Santo. International Atomic Energy Agency; AustriaFil: Vera, MarÃa Teresa. Consejo Nacional de Investigaciones CientÃficas y Técnicas; Argentina. Universidad Nacional de Tucumán. Facultad de AgronomÃa y Zootecnia. Cátedra Terapéutica Vegetal; Argentin
An ontology-based framework for describing discoverable data services
Data-services are applications in charge of retrieving certain data when they are called. They are found in different communities such as the Internet Of Things, Cloud Computing, Big Data, etc. So, there is a real need to discover how can an application that requires some data automatically find a data-service which is providing it. To our knowledge, the problem of automatically discovering these data-services is still open. To make a step forward in this direction, we propose an ontology-based framework to address this problem. In our framework, input and output values of the request are mapped into concepts of the domain ontology. Then, data-services specify how to obtain the output from the input by stating the relationship between the mapped concepts of the ontology.Peer ReviewedPostprint (author's final draft
- …