Identidad latinoamericana de jóvenes activistas en espacios políticos internacionales

El presente estudio analiza la construcción de identidad latinoamericana en los espacios creados por las instituciones internacionales. Mediante el análisis cualitativo de los discursos de los jóvenes participantes se demuestra que la construcción de la identidad latinoamericana, dentro del marco institucional, se sustenta en discursos dialécticos entre lo local-nacional, lo regional y lo internacional reflejando el esquema estructural organizativo de la política internacional. El Estado-nación sigue teniendo un rol relevante dentro de la estructura organizativa de los espacios internacionales y por ende decisivo para la construccion de la identidad latinoamericana de los jóvenes en estos espacios

Study of an overmoded structure for megawatt Ka-band extended interaction klystron

For most applications in the millimeter wave band, corresponding to Ka and higher-frequency bands, relatively high atmospheric absorption necessitates the use of high-power sources. Here, a new approach for projecting an oversized beam tunnel in an overmoded structure by concentrating the axial field is demonstrated to meet the high-frequency and high-power demands of compact devices. Due to the enhanced intense beam loading capability of the interaction circuit, a six-cavity Ka-band extended interaction klystron with a four-coupling-hole disk-loaded structure is designed that can stably obtain high output power. An analysis of optimization tradeoffs from introducing high order modes for allowing the application of more powerful beams to improving high order mode field distribution for enhancing the electron-wave coupling and suppressing mode competition is reported. 3D particle-in-cell simulations show attainable output powers of 1.11 MW at 32.94 GHz with a saturated gain of 57 dB by injecting a 3.3 mm diameter electron beam with a current of 24 A.</p

Altered resting-state network connectivity in stroke patients with and without apraxia of speech

Motor speech disorders, including apraxia of speech (AOS), account for over 50% of the communication disorders following stroke. Given its prevalence and impact, and the need to understand its neural mechanisms, we used resting state functional MRI to examine functional connectivity within a network of regions previously hypothesized as being associated with AOS (bilateral anterior insula (aINS), inferior frontal gyrus (IFG), and ventral premotor cortex (PM)) in a group of 32 left hemisphere stroke patients and 18 healthy, age-matched controls. Two expert clinicians rated severity of AOS, dysarthria and nonverbal oral apraxia of the patients. Fifteen individuals were categorized as AOS and 17 were AOS-absent. Comparison of connectivity in patients with and without AOS demonstrated that AOS patients had reduced connectivity between bilateral PM, and this reduction correlated with the severity of AOS impairment. In addition, AOS patients had negative connectivity between the left PM and right aINS and this effect decreased with increasing severity of non-verbal oral apraxia. These results highlight left PM involvement in AOS, begin to differentiate its neural mechanisms from those of other motor impairments following stroke, and help inform us of the neural mechanisms driving differences in speech motor planning and programming impairment following stroke

Deformed "Commutative" Chern - Simons System

Noncommutative Chern - Simons' system is non-perturbatively investigated at a full deformed level. A deformed "commutative" phase space is found by a non-canonical change between two sets of deformed variables of noncommutative space. It is explored that in the "commutative" phase space all calculations are similar to the case in commutative space. Spectra of the energy and angular momentum of the Chern - Simons' system are obtained at the full deformed level. The noncommutative-commutative correspondence is clearly showed. Formalism for the general dynamical system is briefly presented. Some subtle points are clarified.Comment: 15 page

Birth Weight for Gestational Age Norms for a Large Cohort of Infants Born to HIV-Negative Women in Botswana Compared with Norms for U.S.-Born Black Infants

Background: Standard values for birth weight by gestational age are not available for sub-Saharan Africa, but are needed to evaluate incidence and risk factors for intrauterine growth retardation in settings where HIV, antiretrovirals, and other in utero exposures may impact birth outcomes. Methods: Birth weight data were collected from six hospitals in Botswana. Infants born to HIV-negative women between 26-44 weeks gestation were analyzed to construct birth weight for gestational age charts. These data were compared with published norms for black infants in the United States. Results: During a 29 month period from 2007-2010, birth records were reviewed in real-time from 6 hospitals and clinics in Botswana. Of these, 11,753 live infants born to HIV-negative women were included in the analysis. The median gestational age at birth was 39 weeks (1st quartile 38, 3rd quartile 40 weeks), and the median birth weight was 3100 grams (1st quartile 2800, 3rd quartile 3400 grams). We constructed estimated percentile curves for birth weight by gestational age which demonstrate increasing slope during the third trimester and leveling off beyond 40 weeks. Compared with black infants in the United States, Botswana-born infants had lower median birth weight for gestational age from weeks 37 through 42 (p < .02). Conclusions: We present birth weight for gestational age norms for Botswana, which are lower at term than norms for black infants in the United States. These findings suggest the importance of regional birth weight norms to identify and define risk factors for higher risk births. These data serve as a reference for Botswana, may apply to southern Africa, and may help to identify infants at risk for perinatal complications and inform comparisons among infants exposed to HIV and antiretrovirals in utero

Laser-sculpted hybrid photonic magnetometer with nanoscale magnetostrictive interaction

We present a new photonic magnetic sensor that can yield information on the spatial angle of rotation of the sensor within a given static magnetic field that based upon an optical fiber platform that has a wavelength-encoded output and a demonstrated sensitivity of 543 pm/mT. This optical fiber magnetic field sensor combines a conventional, UV-laser inscribed long period grating (LPG) with a magnetostrictive material Terfenol-D that coats and fills 50-μm micro-slots running adjacent and parallel to the fiber central axis. The micro-slots are produced using a femtosecond laser and selective chemical etching. A detection limit for a static magnetic field strength of ±50μT is realized in low strength DC magnetic field (below 0.4 mT), this performance approaches the Earth’s magnetic field strength and thus, once optimized, has potential for navigation applications. Our method addresses the major drawback of conventional sensors, namely their inadequate sensitivity to low strength, static magnetic fields and their inability to provide information about the orientation and magnitude

Deciphering neo-sex and B chromosome evolution by the draft genome of Drosophila albomicans

<p>Abstract</p> <p>Background</p> <p><it>Drosophila albomicans </it>is a unique model organism for studying both sex chromosome and B chromosome evolution. A pair of its autosomes comprising roughly 40% of the whole genome has fused to the ancient X and Y chromosomes only about 0.12 million years ago, thereby creating the youngest and most gene-rich neo-sex system reported to date. This species also possesses recently derived B chromosomes that show non-Mendelian inheritance and significantly influence fertility.</p> <p>Methods</p> <p>We sequenced male flies with B chromosomes at 124.5-fold genome coverage using next-generation sequencing. To characterize neo-Y specific changes and B chromosome sequences, we also sequenced inbred female flies derived from the same strain but without B's at 28.5-fold.</p> <p>Results</p> <p>We assembled a female genome and placed 53% of the sequence and 85% of the annotated proteins into specific chromosomes, by comparison with the 12 <it>Drosophila genomes</it>. Despite its very recent origin, the non-recombining neo-Y chromosome shows various signs of degeneration, including a significant enrichment of non-functional genes compared to the neo-X, and an excess of tandem duplications relative to other chromosomes. We also characterized a B-chromosome linked scaffold that contains an actively transcribed unit and shows sequence similarity to the subcentromeric regions of both the ancient X and the neo-X chromosome.</p> <p>Conclusions</p> <p>Our results provide novel insights into the very early stages of sex chromosome evolution and B chromosome origination, and suggest an unprecedented connection between the births of these two systems in <it>D. albomicans</it>.</p