Resonant tunneling through a small quantum dot coupled to superconducting leads

We address the problem of non-linear transport through discrete electronic levels in a small quantum dot coupled to superconducting electrodes. In our approach the low temperature I-V characteristics can be calculated including all multiple quasi-particle and Andreev processes. The limit of very weak coupling to the leads and large charging energies is briefly analyzed comparing the calculated lineshapes of the I-V curves with recent experimental results. When the coupling to the leads increases and Coulomb blockade effects can be neglected, the combination of multiple Andreev processes and resonant transmission gives rise to a rich subgap structure which largely differs from the one found in the more studied S-N-S systems. We show how multiple processes can be included within a simple sequential tunneling picture qualitatively explaining the subgap structure. We suggest an experimental set-up where the predicted effects could be observed.Comment: 11 pages, 4 postscript figures, to be published in Phys. Rev. B (rapid communications

Association between time to reperfusion and outcome is primarily driven by the time from imaging to reperfusion

Background and Purpose A progressive decline in the odds of favorable outcome as time to reperfusion increases is well known. However, the impact of specific workflow intervals is not clear.; Methods We studied the mechanical thrombectomy group (n=103) of the prospective, randomized REVASCAT (Randomized Trial of Revascularization With Solitaire FR Device Versus Best Medical Therapy in the Treatment of Acute Stroke due to Anterior Circulation Large Vessel Occlusion Presenting Within Eight Hours of Symptom Onset) trial. We defined 3 workflow metrics: time from symptom onset to reperfusion (OTR), time from symptom onset to computed tomography, and time from computed tomography (CT) to reperfusion. Clinical characteristics, core laboratory-evaluated Alberta Stroke Program Early CT Scores (ASPECTS) and 90-day outcome data were analyzed. The effect of time on favorable outcome (modified Rankin scale, 0-2) was described via adjusted odds ratios (ORs) for every 30-minute delay.; Results Median admission National Institutes of Health Stroke Scale was 17.0 (14.0-20.0), reperfusion rate was 66%, and rate of favorable outcome was 43.7%. Mean (SD) workflow times were as follows: OTR: 342 (107) minute, onset to CT: 204 (93) minute, and CT to reperfusion: 138 (56) minute. Longer OTR time was associated with a reduced likelihood of good outcome (OR for 30-minute delay, 0.74; 95% confidence interval [CI], 0.59-0.93). The onset to CT time did not show a significant association with clinical outcome (OR, 0.87; 95% CI, 0.67-1.12), whereas the CT to reperfusion interval showed a negative association with favorable outcome (OR, 0.72; 95% CI, 0.54-0.95). A similar subgroup analysis according to admission ASPECTS showed this relationship for OTR time in ASPECTS<8 patients (OR, 0.56; 95% CI, 0.35-0.9) but not in ASPECTS8 (OR, 0.99; 95% CI, 0.68-1.44).; Conclusions Time to reperfusion is negatively associated with favorable outcome, being CT to reperfusion, as opposed to onset to CT, the main determinant of this association. In addition, OTR was strongly associated to outcome in patients with low ASPECTS scores but not in patients with high ASPECTS scores.; Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT01692379.Peer ReviewedPostprint (author's final draft

Host specificity and risk assessment of Archanara geminipuncta and Archanara neurica, two potential biocontrol agents for invasive Phragmites australis in North America

Invasive Phragmites australis is widespread in North America and despite decades of management and large annual expenditures (\u3e5 million US$) using physical and chemical means, local populations and the species range are expanding. Allowing continued expansion does not only threaten native wetland biota but also an endemic North American subspecies Phragmites australis americanus. We used extensive multi-pronged investigations in Europe and North America to evaluate host specificity and impact of two European stem mining noctuid moths, Archanara geminipuncta and A. neurica. Both moth species are specific to the genus Phragmites and both show a very strong, but not absolute, preference for invasive P. australis over endemic P. australis americanus. No-choice tests or tests in small cages provided inconsistent results, but both moths showed consistently high preferences for introduced P. australis. Open field multiple-choice oviposition tests affirmed this; moths laid 6.5% of their eggs on native P. australis americanus. The native subspecies is further safeguarded by increased mortality of eggs and larvae when laid on, or developing in P. australis americanus. Phragmites populations in the southern US, particularly along the Gulf of Mexico, occur outside the climate range of these two temperate moth species. We consider potential threats to P. australis americanus demography due to A. geminipuncta and A. neurica attack to be far smaller than allowing expansion of invasive P. australis to continue. We therefore recommend release of these two biocontrol agents in North America

El desarrollo del pensamiento espacial de los estudiantes de arquitectura a través de una clase de dibujo libre

Trabajo de investigación que busca describir la forma en que los alumnos de Arquitectura adquieren la habilidad para dibujar como parte del desarrollo de su pensamiento espacial y cuáles son las acciones de la práctica docente que contribuyen a que los alumnos descubran las características del objeto observado y utilicen el pensamiento espacial. Conocer acerca del desarrollo espacial de los jóvenes universitarios podría aportar elementos valiosos que los docentes del área y asignaturas como Dibujo técnico, Geometría descriptiva y Perspectiva podrían retomar y potenciar en la enseñanza

The use of cosmic muons in detecting heterogeneities in large volumes

The muon intensity attenuation method to detect heterogeneities in large matter volumes is analyzed. Approximate analytical expressions to estimate the collection time and the signal to noise ratio, are proposed and validated by Monte Carlo simulations. Important parameters, including point spread function and coordinate reconstruction uncertainty are also estimated using Monte Carlo simulations.Comment: 8 pages, 11 figures, submetted to NIM

In-solution Y-chromosome capture-enrichment on ancient DNA libraries.

As most ancient biological samples have low levels of endogenous DNA, it is advantageous to enrich for specific genomic regions prior to sequencing. One approach-in-solution capture-enrichment-retrieves sequences of interest and reduces the fraction of microbial DNA. In this work, we implement a capture-enrichment approach targeting informative regions of the Y chromosome in six human archaeological remains excavated in the Caribbean and dated between 200 and 3000 years BP. We compare the recovery rate of Y-chromosome capture (YCC) alone, whole-genome capture followed by YCC (WGC + YCC) versus non-enriched (pre-capture) libraries. The six samples show different levels of initial endogenous content, with very low (&lt; 0.05%, 4 samples) or low (0.1-1.54%, 2 samples) percentages of sequenced reads mapping to the human genome. We recover 12-9549 times more targeted unique Y-chromosome sequences after capture, where 0.0-6.2% (WGC + YCC) and 0.0-23.5% (YCC) of the sequence reads were on-target, compared to 0.0-0.00003% pre-capture. In samples with endogenous DNA content greater than 0.1%, we found that WGC followed by YCC (WGC + YCC) yields lower enrichment due to the loss of complexity in consecutive capture experiments, whereas in samples with lower endogenous content, the libraries' initial low complexity leads to minor proportions of Y-chromosome reads. Finally, increasing recovery of informative sites enabled us to assign Y-chromosome haplogroups to some of the archeological remains and gain insights about their paternal lineages and origins. We present to our knowledge the first in-solution capture-enrichment method targeting the human Y-chromosome in aDNA sequencing libraries. YCC and WGC + YCC enrichments lead to an increase in the amount of Y-DNA sequences, as compared to libraries not enriched for the Y-chromosome. Our probe design effectively recovers regions of the Y-chromosome bearing phylogenetically informative sites, allowing us to identify paternal lineages with less sequencing than needed for pre-capture libraries. Finally, we recommend considering the endogenous content in the experimental design and avoiding consecutive rounds of capture, as clonality increases considerably with each round

The O-mannosylation and production of recombinant APA (45/47 KDa) protein from Mycobacterium tuberculosis in Streptomyces lividans is affected by culture conditions in shake flasks

<p>Abstract</p> <p>Background</p> <p>The Ala-Pro-rich <it>O</it>-glycoprotein known as the 45/47 kDa or APA antigen from <it>Mycobacterium tuberculosis </it>is an immunodominant adhesin restricted to mycobacterium genus and has been proposed as an alternative candidate to generate a new vaccine against tuberculosis or for diagnosis kits. In this work, the recombinant <it>O</it>-glycoprotein APA was produced by the non-pathogenic filamentous bacteria <it>Streptomyces lividans</it>, evaluating three different culture conditions. This strain is known for its ability to produce heterologous proteins in a shorter time compared to <it>M. tuberculosis</it>.</p> <p>Results</p> <p>Three different shake flask geometries were used to provide different shear and oxygenation conditions; and the impact of those conditions on the morphology of <it>S. lividans </it>and the production of rAPA was characterized and evaluated. Small unbranched free filaments and mycelial clumps were found in baffled and coiled shake flasks, but one order of magnitude larger pellets were found in conventional shake flasks. The production of rAPA is around 3 times higher in small mycelia than in larger pellets, most probably due to difficulties in mass transfer inside pellets. Moreover, there are four putative sites of <it>O</it>-mannosylation in native APA, one of which is located at the carboxy-terminal region. The carbohydrate composition of this site was determined for rAPA by mass spectrometry analysis, and was found to contain different glycoforms depending on culture conditions. Up to two mannoses residues were found in cultures carried out in conventional shake flasks, and up to five mannoses residues were determined in coiled and baffled shake flasks.</p> <p>Conclusions</p> <p>The shear and/or oxygenation parameters determine the bacterial morphology, the productivity, and the <it>O</it>-mannosylation of rAPA in <it>S. lividans</it>. As demonstrated here, culture conditions have to be carefully controlled in order to obtain recombinant <it>O</it>-glycosylated proteins with similar "quality" in bacteria, particularly, if the protein activity depends on the glycosylation pattern. Furthermore, it will be an interesting exercise to determine the effect of shear and oxygen in shake flasks, to obtain evidences that may be useful in scaling-up these processes to bioreactors. Another approach will be using lab-scale bioreactors under well-controlled conditions, and study the impact of those on rAPA productivity and quality.</p

Reconocimiento de Personas en Ambiente con Emisiones de Humo Usando Sensor Laser y Redes Neuronales Convolucionales desde Nube de Puntos 3D. Parte 1.

Cuando ocurren incendios en Plantas industriales, los materiales siniestrados y el humo dificultan la identificación del personal. Los Drones con sensores laser y redes CNN posibilitan el reconocimiento de personas en tales ambientes. El objetivo del proyecto es el estudio de un sistema neuronal convolucional para el reconocimiento de personas en un ambiente con emisiones de humo (parte1) y para su implementación usa un sensor laser, una tarjeta controladora y un dron (parte2). El método empleado consideró la realización de un reconocimiento de personas usando una red CNN previamente entrenada con nube de puntos 3D. La prueba se realizó con Alexnet e imágenes de personas. Los resultados (parte1) muestran que una matriz de confusión del 97.5 % ha sido alcanzada. Basado en el estudio, se concluye que el sistema neuronal de reconocimiento de personas usando CNN en ambientes siniestrados presenta un comportamiento muy aceptable para su aplicabilidad.Palabras clave: reconocimiento de personas, redes neuronales convolucionales, programación en entorno Matlab, sensor laser y dron

Recognition of People in Environment with Smoke Emissions Using Laser Sensor and Convolutional Neural Networks from 3D Pointed Cloud.

Cuando ocurren incendios en Plantas industriales, los materiales siniestrados y el humo dificultan la identificación del personal. Los Drones con sensores laser y redes CNN posibilitan el reconocimiento de personas en tales ambientes.  El objetivo del proyecto es el estudio de un sistema neuronal convolucional para el reconocimiento de personas en un ambiente con emisiones de humo (parte1) y para su implementación usa un sensor laser, una tarjeta controladora y un dron (parte2). El método empleado consideró la realización de un reconocimiento de personas usando una red CNN previamente entrenada con nube de puntos 3D. La prueba se realizó con Alexnet e imágenes de personas. Los resultados (parte1) muestran que una matriz de confusión del 97.5 % ha sido alcanzada. Basado en el estudio, se concluye que el sistema neuronal de reconocimiento de personas usando CNN en ambientes siniestrados presenta un comportamiento muy aceptable para su aplicabilidad. Palabras clave: reconocimiento de personas, redes neuronales convolucionales, programación en entorno Matlab, sensor laser y dron