Composite polymer membranes for laserinduced fluorescence thermometry

We demonstrate a modified version of laser-induced fluorescence thermometry (LIFT) for mapping temperature gradients in the vicinity of small photothermal devices. Our approach is based on temperature sensitive fluorescent membranes fabricated with rhodamine B and polydimethylsiloxane (PDMS). Relevant membrane features for LIFT, such as temperature sensitivity, thermal quenching and photobleaching are presented for a range of 25 °C to 90 °C, and their performance is evaluated upon obtaining the temperature gradients produced in the proximity of optical fiber micro-heaters. Our results show that temperature measurements in regions as small as 750 μm x 650 μm, with a temperature resolution of 1 °C, can be readily obtained

El piearcts en querétaro - tercera etapa

Se reporta el avance de la tercera etapa del PIEARCTS en Querétaro, México: análisis estadístico e interpretación de datos de las once instituciones en donde se aplicó el COCTS a un total de 1374 sujetos. Se establece un horizonte de interpretación que integra los datos cuantitativos con la reflexión cualitativa, la cual está amparada en el contexto socio-histórico de cada institución y en la caracterización de cada grupo muestral. Los datos se analizan de acuerdo con el tipo de institución: tecnológica o humanística; nivel educativo: licenciatura, bachillerato, técnico o normal y con los grupos encuestados: estudiantes o profesores, considerando los datos sociodemográficos incluidos en la encuesta. Se calculan los índices de plausibilidad, adecuación, ingenuidad y cultura científica para cada reactivo y para cada sujeto. Con ellos se hacen comparaciones entre grupos

Influence of radiative forcing factors on ground–air temperature coupling during the last millennium: implications for borehole climatology

Past climate variations may be uncovered via reconstruction methods that use proxy data as predictors. Among them, borehole reconstruction is a well-established technique to recover the long-term past surface air temperature (SAT) evolution. It is based on the assumption that SAT changes are strongly coupled to ground surface temperature (GST) changes and transferred to the subsurface by thermal conduction. We evaluate the SAT–GST coupling during the last millennium (LM) using simulations from the Community Earth System Model LM Ensemble (CESM-LME). The validity of such a premise is explored by analyzing the structure of the SAT–GST covariance during the LM and also by investigating the evolution of the long-term SAT–GST relationship. The multiple and single-forcing simulations in the CESM-LME are used to analyze the SAT–GST relationship within different regions and spatial scales and to derive the influence of the different forcing factors on producing feedback mechanisms that alter the energy balance at the surface. The results indicate that SAT–GST coupling is strong at global and above multi-decadal timescales in CESM-LME, although a relatively small variation in the long-term SAT–GST relationship is also represented. However, at a global scale such variation does not significantly impact the SAT–GST coupling, at local to regional scales this relationship experiences considerable long-term changes mostly after the end of the 19th century. Land use land cover changes are the main driver for locally and regionally decoupling SAT and GST, as they modify the land surface properties such as albedo, surface roughness and hydrology, which in turn modifies the energy fluxes at the surface. Snow cover feedbacks due to the influence of other external forcing are also important for corrupting the long-term SAT–GST coupling. Our findings suggest that such local and regional SAT–GST decoupling processes may represent a source of bias for SAT reconstructions from borehole measurement, since the thermal signature imprinted in the subsurface over the affected regions is not fully representative of the long-term SAT variations.Ministerio de Industria, Comercio y Competitividad (FPI grant no. BES-2015-075019)Versión del editor3,50

Top quark tensor couplings

We compute the real and imaginary parts of the one-loop electroweak contributions to the left and right tensorial anomalous couplings of the $tbW$ vertex in the Standard Model (SM). For both tensorial couplings we find that the real part of the electroweak SM correction is close to 10$$ of the leading contribution given by the QCD gluon exchange. We also find that the electroweak real and imaginary parts for the anomalous right coupling are almost of the same order of magnitude. The one loop SM prediction for the real part of the left coupling is close to the 3$\sigma$ discovery limit derived from $b\rightarrow s \gamma$. Besides, taking into account that the predictions of new physics interactions are also at the level of a few percents when compared with the one loop QCD gluon exchange, these electroweak corrections should be taken into account in order to disentangle new physics effects from the standard ones. These anomalous tensorial couplings of the top quark will be investigated at the LHC in the near future where sensitivity to these contributions may be achieved.Comment: 16 pages, 2 figure

tempo and mode of allopatric divergence in the weakly electric fish Sternopygus dariensis in the Isthmus of Panama

Spatial isolation is one of the main drivers of allopatric speciation, but the extent to which spatiallysegregated populations accumulate genetic differences relevant to speciation is not always clear. We used data from ultraconserved elements (UCEs) and whole mitochondrial genomes (i.e., mitogenomes) to explore genetic variation among allopatric populations of the weakly electric fish Sternopygus dariensis across the Isthmus of Panama. We found strong genetic divergence between eastern and western populations of S. dariensis. Over 77% of the UCE loci examined were differentially fixed between populations, and these loci appear to be distributed across the species’ genome. Population divergence occurred within the last 1.1 million years, perhaps due to global glaciation oscillations during the Pleistocene. Our results are consistent with a pattern of genetic differentiation under strict geographic isolation, and suggest the presence of incipient allopatric species within S. dariensis. Genetic divergence in S. dariensis likely occurred in situ, long after the closure of the Isthmus of Panama. Our study highlights the contribution of spatial isolation and vicariance to promoting rapid diversification in Neotropical freshwater fishes. The study of spatially-segregated populations within the Isthmus of Panama could reveal how genetic differences accumulate as allopatric speciation proceeds.Spatial isolation is one of the main drivers of allopatric speciation, but the extent to which spatiallysegregated populations accumulate genetic differences relevant to speciation is not always clear. We used data from ultraconserved elements (UCEs) and whole mitochondrial genomes (i.e., mitogenomes) to explore genetic variation among allopatric populations of the weakly electric fish Sternopygus dariensis across the Isthmus of Panama. We found strong genetic divergence between eastern and western populations of S. dariensis. Over 77% of the UCE loci examined were differentially fixed between populations, and these loci appear to be distributed across the species’ genome. Population divergence occurred within the last 1.1 million years, perhaps due to global glaciation oscillations during the Pleistocene. Our results are consistent with a pattern of genetic differentiation under strict geographic isolation, and suggest the presence of incipient allopatric species within S. dariensis. Genetic divergence in S. dariensis likely occurred in situ, long after the closure of the Isthmus of Panama. Our study highlights the contribution of spatial isolation and vicariance to promoting rapid diversification in Neotropical freshwater fishes. The study of spatially-segregated populations within the Isthmus of Panama could reveal how genetic differences accumulate as allopatric speciation proceeds

Renewable oxygenated additives in biofuels : high pressure densities of mixtures dibutyl-ether + heptane at high temperature and pressure

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.The increasing worldwide use of bio-fuels constitutes one of the measures considered to reduce greenhouse gas emissions. Bio-fuels also have an important part to play in promoting the security of energy supply, and promoting technological development and innovation. Di-butyl ether (DBE) is used as blending agent in reformulated gasoline and has been included in recent international regulations on the promotion of the use of energy from renewable sources for transport. The DBE is a non-polluting, high octane number blending agent. DBE could be also used as cetane enhancer in bio-diesel fuel, and can be obtained as an added valued additive to second generation bio-fuels. Second generation bio-fuels could be obtained from ligno-cellulosic biomass and waste materials. Ether + alkane mixtures are of interest as model mixtures for gasoline in which the ether act as renewable, high octane number blending agent. From this point of view the study of the binary mixtures dibutyl ether + heptane, are very interesting. Heptane has been chosen as a representative of the linear alkanes that contain real gasoline. Density of the binary mixtures DBE + heptane and its pure compounds have been measured under pressure and reported in this work using a vibrating tube densitometer. Accurate PVT properties of pure ethers and its mixtures are required to develop and test equations of state, because equations of state are critical to design storage and transport systems in the fuel industry. Moreover, high temperature and pressure data serve to validate equations of state which are reliable for the increasingly use of industrial and engine processes under hard conditions. Experimental densities (826 points) for the compressed liquid phase of the binary systems DBE + heptane have been measured at 298.15, 313.15, 333.15, 353.15, 373.15 and 393.15 K and at pressures up to 140 MPa, with an absolute uncertainty of 0.7 kg·m-3. For each composition, the experimental values were correlated using a Tait-type equation. Results show non-linear behaviour of the mixture.dc201

In Vivo Confirmation of the Role of Statins in Reducing Nitric Oxide and C-Reactive Protein Levels in Peripheral Arterial Disease

AbstractObjectivesInflammatory and other processes mediating impairment of endothelial function, where there are increased levels of C-reactive protein (CRP) and plasma nitrites, have a part to play in the early stages of peripheral arterial disease (PAD). Our objective was to analyse the effect of statins on the plasma nitrite and CRP levels in PAD.Material and methodsA prospective study of 30 patients with PAD Fontaine stage II, with no prior treatment with statins, determined high sensitivity (hs)-CRP and lipid profile in the patients. Plasma nitrite levels were determined by colourimetric assay based on the Griess reaction, at baseline and after 1 month of treatment with atorvastatin 40mgday−1.ResultsA significant reduction in plasma nitrite levels was detected after the treatment with statins (11.88±7.8μM vs. 5.7±1.8μM, p=0.0001). There was also a significant reduction in hs-CRP levels (13.58±24.00 vs. 3.93±3.19, p=0.02).When the patients were stratified according to claudication stage, a significant reduction in nitrite levels was obtained, both in patients with PAD Fontaine stage IIA (9.5±3.3μM vs. 5.3±1.7μM, p=0.0001) and in stage IIB (16.6±11.6μM vs. 6.7±1.8μM, p=0.032).ConclusionsTreatment with statins lowers plasma nitrite and CRP levels in patients with PAD. Our data support the effects of statins in vivo that have been demonstrated on the endothelium ex vivo, suggesting a beneficial effect by acting on the initial processes that trigger the disease, reducing oxidative stress (increase in the bioavailability of nitric oxide as peroxynitrite levels decrease) and curtailing the inflammatory processes which perpetuate the disease

Evaluation of the contribution of D9S1120 to anthropological studies in Native American populations

The D9S1120 locus exhibits a population-specific allele of 9 repeats (9RA) in all Native American and two Siberian populations currently studied, but it is absent in other worldwide populations. Although this feature has been used in anthropological genetic studies, its impact on the evaluation of the structure and genetic relations among Native American populations has been scarcely assessed. Consequently, the aim of this study was to evaluate the anthropological impact of D9S1120 when it was added to STR population datasets in Mexican Native American groups. We analyzed D9S1120 by PCR and capillary electrophoresis (CE) in 1117 unrelated individuals from 13 native groups from the north and west of Mexico. Additional worldwide populations previously studied with D9S1120 and/or 15 autosomal STRs (Identifier kit) were included for interpopulation analyses. We report statistical results of forensic importance for D9S1120. On average, the modal alleles were the Native American-specific allele 9RA (0.3254) and 16 (0.3362). Genetic distances between Native American and worldwide populations were estimated. When D9S1120 was included in the 15 STR population dataset, we observed improvements for admixture estimation in Mestizo populations and for representing congruent genetic relationships in dendrograms. Analysis of molecular variance (AMOVA) based on D9S1120 confirms that most of the genetic variability in the Mexican population is attributable to their Native American backgrounds, and allows the detection of significant intercontinental differentiation attributed to the exclusive presence of 9RA in America. Our findings demonstrate the contribution of D9S1120 to a better understanding of the genetic relationships and structure among Mexican Native groups.CONACYT (Consejo Nacional de Ciencia y Tecnología) (México)Depto. de Biodiversidad, Ecología y EvoluciónFac. de Ciencias BiológicasTRUEinpres