The evaluation of surface diffusion coefficients of gold and platinum atoms at electrochemical interfaces from combined STM-SEM imaging and electrochemical techniques

A simple method is presented for measuring the surface diffusion coefficients of Au and Pt atoms at electrodispersed electrodes of the same metals in contact with 0.5M H2SO4. The technique is based upon the time dependence of the surface roughness factor of electrodispersed metal overlayers. The method requires a model for the surface roughness of the metal structure. The model is deduced from microscopic measurements by a STM integrated into a conventional SEM microscope. This allows the relationship between the roughness factor and the area of the surface structure to be obtained. For Au and Pt in contact with an electrolyte solution, the values of our diffusion coefficients are higher than those reported in vacuum at the same temperature.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA)Facultad de Ciencias Exacta

Samarium iodide-promoted asymmetric Reformatsky reaction of 3-(2-Haloacyl)-2-oxazolidinones with enals

3-(2-Haloacyl)-2-oxazolidinones were shown to react with enals in an asymmetric SmI2-promoted Reformatsky reaction to give stereochemically well-defined 3-hydroxy-4-alkenyl- and 3-hydroxy-2-methyl-4-alkenyl imides. Chirality transfer of the Evans (S)-oxazolidinone unit via a Zimmerman-Traxler-like transition state resulted in Reformatsky products with a relative syn-configuration. The absolute configuration of compounds obtained is opposite to the corresponding products obtained via aldol addition of boron enolates to enals using the same Evans oxazolidinones

Activation of High and Low Affinity Dopamine Receptors Generates a Closed Loop that Maintains a Conductance Ratio and its Activity Correlate

Neuromodulators alter network output and have the potential to destabilize a circuit. The mechanisms maintaining stability in the face of neuromodulation are not well described. Using the pyloric network in the crustacean stomatogastric nervous system, we show that dopamine (DA) does not simply alter circuit output, but activates a closed loop in which DA-induced alterations in circuit output consequently drive a change in an ionic conductance to preserve a conductance ratio and its activity correlate. DA acted at low affinity type 1 receptors (D1Rs) to induce an immediate modulatory decrease in the transient potassium current (I A ) of a pyloric neuron. This, in turn, advanced the activity phase of that component neuron, which disrupted its network function and thereby destabilized the circuit. DA simultaneously acted at high affinity D1Rs on the same neuron to confer activity-dependence upon the hyperpolarization activated current (I h ) such that the DA- induced changes in activity subsequently reduced I h . This DA-enabled, activity-dependent, intrinsic plasticity exactly compensated for the modulatory decrease in I A to restore the I A :I h ratio and neuronal activity phase, thereby closing an open loop created by the modulator. Activation of closed loops to preserve conductance ratios may represent a fundamental operating principle neuromodulatory systems use to ensure stability in their target networks

Scanning tunneling microscopy of electrochemically activated platinum surfaces : A direct ex-situ determination of the electrode nanotopography

A direct scanning tunneling microscopy ex-situ determination on the nanometer scale of the topography of electrochemically highly activated platinum electrodes is presented. A correlation between catalytic activity and surface microtopography becomes evident. This result gives support to a structural model for the activated electrode surface. In the model, a volume with a pebble-like structure allows electrocatalytic processes to occur practically free of diffusion relaxation contributions under usual voltammetric conditions.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

CLA-producing adjunct cultures improve the nutritional value of sheep cheese fat

[EN]The influence of the autochthonous CLA-producing Lactobacillus plantarum TAUL 1588 and Lactobacillus casei subsp. casei SS 1644 strains and the ripening time on the fatty acid (FA) content and sensory characteristics of sheep cheese were investigated. Three cheese types with different cultures and the control cheese were produced in duplicate and ripened for 8 months. 86 individual FA were determined by gas chromatography. Ripening time (2, 90, 180 and 240 days) did not have a significant effect (P >.05) on the FA content. However, the presence of both Lactobacillus CLA-producing strains led to a decrease of the saturated FA content and to 1.30, 1.19 and 1.27 times higher levels of vaccenic acid, CLA and omega-3, respectively, when compared to the control cheese. This combination allowed obtaining sheep milk cheeses with a healthier FA content, without appreciable changes on sensory characteristics. This work could be a promising approach to increase the bioactive fatty acid content of cheeses.SIThe authors are grateful to the University of León (León, Spain) for granting a PhD fellowship to Erica Renes Bañuelos. Pilar Gómez-Cortés was subsidized with a Juan de la Cierva research contract from the Ministerio de Economía y Competitividad. The authors also wish to acknowledge the Consortium for Ovine Promotion (Villalpando, Zamora, Castilla-León, Spain). The authors thank to F.J. Zorita for his technical assistance

ChaLearn LAP 2016: First Round Challenge on First Impressions - Dataset and Results

This paper summarizes the ChaLearn Looking at People 2016 First Impressions challenge data and results obtained by the teams in the first round of the competition. The goal of the competition was to automatically evaluate five “apparent” personality traits (the so-called “Big Five”) from videos of subjects speaking in front of a camera, by using human judgment. In this edition of the ChaLearn challenge, a novel data set consisting of 10,000 shorts clips from YouTube videos has been made publicly available. The ground truth for personality traits was obtained from workers of Amazon Mechanical Turk (AMT). To alleviate calibration problems between workers, we used pairwise comparisons between videos, and variable levels were reconstructed by fitting a Bradley-Terry-Luce model with maximum likelihood. The CodaLab open source platform was used for submission of predictions and scoring. The competition attracted, over a period of 2 months, 84 participants who are grouped in several teams. Nine teams entered the final phase. Despite the difficulty of the task, the teams made great advances in this round of the challenge

Effect of forage type in the ovine diet on the nutritional profile of sheep milk cheese fat

[EN] The high nutritional value of sheep milk can be advantageous in the manufacture of cheese, and fat plays an important role in sheep cheese properties. The aim of this study was to investigate the effect of feeding common hay or silage diets used in commercial farms on the nutritional value of sheep cheese fat. We also monitored the effect of cheese ripening period on the fatty acid profile. Cheeses were produced from milk of sheep fed hay and silage diets from 8 farms, on 4 separate occasions (February, May, August, and November) over a 1-yr period. Eighty-four individual fatty acids were determined and identified by gas chromatography. Ripening time (100 and 180 d) significantly reduced moisture, acidity, and water activity of cheeses but did not affect the fatty acid content. However, hay feeding, compared with silage feeding, led to cheeses with 1.5- and 1.3-fold higher contents of vaccenic acid and conjugated linoleic acid, without detrimental changes in saturated and n-3 (omega-3) fatty acid composition. Hay forages could be a low-cost alternative for producing cheese with a fatty acid profile suitable for human health, which is an aspect of great interest to the food industrySIThis work was supported by the Ministerio de Economía y Competitividad (Project AGL2016-75159- C2-2-R; Madrid, Spain) and the Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (Project TA2014-00069-CO2-02; Madrid, Spain). The authors also acknowledge Entrepinares S.A.U. Company (Valladolid, Spain) for the help in the cheese-making trial

The one-loop and Sommerfeld electroweak corrections to the Wino dark matter annihilation

We compute the present-day Wino dark matter annihilation cross-section including the one-loop radiative corrections together with the fully treated electroweak Sommerfeld effect. We discuss what is the consistent way of incorporating these two corrections simultaneously and why simply using the running coupling constants values at the Wino mass scale is not correct. The results show that up to a few TeV scale the full one-loop computation makes the cross-section smaller up to about 30% with respect to the Sommerfeld enhanced tree level result and are considerably larger than the tree or one-loop level without the Sommerfeld effect.Comment: 25 pages, 13 figures; clarifications on the range of validity of the results, in particular for the annihilation into neutral gauge bosons; attached tabulated results for the cross-section