Identidad y práctica profesionales del educador y la educadora de calle en México

El presente artículo tiene como objetivo analizar algunos de los factores que en la actualidad impiden la construcción de la identidad y práctica profesionales de los educadores y educadoras de calle que laboran en las organizaciones de la sociedad civil en México. El texto se desarrolla en base a la experiencia del autor y de la autora como educadores de calle, así como en datos cualitativos recolectados a través de una entrevista colectiva semiestructurada llevada a cabo con un grupo de educadores y educadoras de calle, y en reflexiones realizadas en diferentes espacios de trabajo. El análisis del discurso tanto de los educadores y educadoras como de las instituciones, permite entender el papel desempeñado hoy en día por los principales actores involucrados con el tema de los niños, niñas y jóvenes que viven en la calle. Este artículo representa uno de los primeros esfuerzos de reflexión sobre el ejercicio profesional de los educadores y las educadoras de calle en México. En este sentido, los planteamientos realizados buscan ser una contribución a la reformulación de la práctica educativa que se dirige a las poblaciones infantiles y juveniles que viven en exclusión social.-I. Introducción. -II. Recolección de datos. -III. Reconocimiento profesional y social. -IV. Perfil profesional. -V. Prácticas de intervención. -VI. Trabajo aislado. -VII. Reflexión sobre la práctica educativa. -VIII. El educador o educadora de calle: ¿actor social o agente institucional? -IX. Conclusiones finales. Lista de referencias

Regulation of NR4A by nutritional status, gender, postnatal development and hormonal deficiency

The NR4A is a subfamily of the orphan nuclear receptors (NR) superfamily constituted by three well characterized members: Nur77 (NR4A1), Nurr1 (NR4A2) and Nor 1 (NR4A3). They are implicated in numerous biological processes as DNA repair, arteriosclerosis, cell apoptosis, carcinogenesis and metabolism. Several studies have demonstrated the role of this subfamily on glucose metabolism, insulin sensitivity and energy balance. These studies have focused mainly in liver and skeletal muscle. However, its potential role in white adipose tissue (WAT), one of the most important tissues involved in the regulation of energy homeostasis, is not well-studied. The aim of this work was to elucidate the regulation of NR4A in WAT under different physiological and pathophysiological settings involved in energy balance such as fasting, postnatal development, gender, hormonal deficiency and pregnancy. We compared NR4A mRNA expression of Nur77, Nurr1 and Nor 1 and found a clear regulation by nutritional status, since the expression of the 3 isoforms is increased after fasting in a leptin-independent manner and sex steroid hormones also modulate NR4A expression in males and females. Our findings indicate that NR4A are regulated by different physiological and pathophysiological settings known to be associated with marked alterations in glucose metabolism and energy status.This work has been supported by grants from Fondo Investigaciones Sanitarias (ST: PI12/02842), Ministerio de Economia y Competitividad (RN: RYC-2008-02219 and BFU2012-35255; MMM: BFU2010-17116), Xunta de Galicia (ML: 10PXIB208164PR and 2012-CP070; RN: EM 2012/039 and 2012-CP069), Centro de Investigación Biomédica en Red (CIBER) de Fisiopatología de la Obesidad y Nutrición. CIBERobn is an initiative of the Instituto de Salud Carlos III (ISCIII) of Spain which is supported by FEDER funds. The research leading to these results has also received funding from the European Community's Seventh Framework Programme under the following grant: ML and RN: FP7/2007-2013: n° 245009: NeuroFASTS

The replication origin of a repABC plasmid

<p>Abstract</p> <p>Background</p> <p><it>repABC </it>operons are present on large, low copy-number plasmids and on some secondary chromosomes in at least 19 α-proteobacterial genera, and are responsible for the replication and segregation properties of these replicons. These operons consist, with some variations, of three genes: <it>repA</it>, <it>repB</it>, and <it>repC</it>. RepA and RepB are involved in plasmid partitioning and in the negative regulation of their own transcription, and RepC is the limiting factor for replication. An antisense RNA encoded between the <it>repB-repC </it>genes modulates <it>repC </it>expression.</p> <p>Results</p> <p>To identify the minimal region of the <it>Rhizobium etli </it>p42d plasmid that is capable of autonomous replication, we amplified different regions of the <it>repABC </it>operon using PCR and cloned the regions into a suicide vector. The resulting vectors were then introduced into <it>R. etli </it>strains that did or did not contain p42d. The minimal replicon consisted of a <it>repC </it>open reading frame under the control of a constitutive promoter with a Shine-Dalgarno sequence that we designed. A sequence analysis of <it>repC </it>revealed the presence of a large A+T-rich region but no iterons or DnaA boxes. Silent mutations that modified the A+T content of this region eliminated the replication capability of the plasmid. The minimal replicon could not be introduced into <it>R. etli </it>strain containing p42d, but similar constructs that carried <it>repC </it>from <it>Sinorhizobium meliloti </it>pSymA or the linear chromosome of <it>Agrobacterium tumefaciens </it>replicated in the presence or absence of p42d, indicating that RepC is an incompatibility factor. A hybrid gene construct expressing a RepC protein with the first 362 amino acid residues from p42d RepC and the last 39 amino acid residues of RepC from SymA was able to replicate in the presence of p42d.</p> <p>Conclusions</p> <p>RepC is the only element encoded in the <it>repABC </it>operon of the <it>R. etli </it>p42d plasmid that is necessary and sufficient for plasmid replication and is probably the initiator protein. The <it>oriV </it>of this plasmid resides within the <it>repC </it>gene and is located close to or inside of a large A+T region. RepC can act as an incompatibility factor, and the last 39 amino acid residues of the carboxy-terminal region of this protein are involved in promoting this phenotype.</p

Synthesis of paramagnetic tetranuclear rhodium and iridium complexes with the 2,6-pyridinedithiolate ligand. Redox-induced degradation to diamagnetic triiridium compounds

The tetranuclear complexes [M4(μ-PyS2)2(diolefin)4] [PyS2 = 2,6-pyridinedithiolate; M = Rh, diolefin = cod (1,5-cyclooctadiene) (1), tfbb (tetrafluorobenzo[5,6]bicyclo[2.2.2]octa-2,5,7-triene) (2); M = Ir, diolefin = cod (3), tfbb (4)] exhibit two one-electron oxidations at a platinum disk electrode in dichloromethane at potentials accessible by chemical reagents. The rhodium tetranuclear complexes were selectively oxidized to the monocationic complexes [Rh4(μ-PyS2)2(diolefin)4] + (1+, 2+) by mild one-electron oxidants such as [Cp2Fe]+ or [N(C6H4Br-4)3]+ and isolated as the PF6 -, BF4 -, and ClO4 - salts. Silver salts behave as noninnocent one-electron oxidants for the reactions with the rhodium complexes 1 and 2 since they give sparingly soluble coordination polymers. The complex [Ir4(μ-PyS2)2(cod)4] + (3+) was obtained as the tetrafluoroborate salt by reaction of 3 with 1 molar equiv of AgBF4, but the related complex 4+ could not be isolated from the chemical oxidation of [Ir4(μ-PyS2)2(tfbb)4] (4) with AgBF4. Oxidation of 3 and 4 with 2 molar equiv of common silver salts resulted in the fragmentation of the complexes to give the diamagnetic triiridium cations [Ir3(μ-PyS2)2(diolefin)3] +. The molecular structure of [Ir3(μ-PyS2)2(cod)3]BF 4, determined by X-ray diffraction methods, showed the three metal atoms within an angular arrangement. Both 2,6-pyridinedithiolate tridentate ligands bridge two metal-metal bonded d7 centers in pseudo octahedral environments and one d8 square-planar iridium center. An interpretation of the EPR spectra of the 63-electron mixed-valence paramagnetic tetranuclear complexes suggests that the unpaired electron is delocalized over two of the metal atoms in the complexes 1+-3+.The generous financial support from Dirección General de Enseñanza Superior e Investigación (DGES) (Projects PB98-641 and PB94-1186), and a fellowship (M. A. Casado) are gratefully acknowledged.Peer Reviewe

A New Optical Density Granulometry-Based Descriptor for the Classification of Prostate Histological Images Using Shallow and Deep Gaussian Processes

[EN] Background and objective Prostate cancer is one of the most common male tumors. The increasing use of whole slide digital scanners has led to an enormous interest in the application of machine learning techniques to histopathological image classification. Here we introduce a novel family of morphological descriptors which, extracted in the appropriate image space and combined with shallow and deep Gaussian process based classifiers, improves early prostate cancer diagnosis. Method We decompose the acquired RGB image in its RGB and optical density hematoxylin and eosin components. Then, we define two novel granulometry-based descriptors which work in both, RGB and optical density, spaces but perform better when used on the latter. In this space they clearly encapsulate knowledge used by pathologists to identify cancer lesions. The obtained features become the inputs to shallow and deep Gaussian process classifiers which achieve an accurate prediction of cancer. Results We have used a real and unique dataset. The dataset is composed of 60 Whole Slide Images. For a five fold cross validation, shallow and deep Gaussian Processes obtain area under ROC curve values higher than 0.98. They outperform current state of the art patch based shallow classifiers and are very competitive to the best performing deep learning method. Models were also compared on 17 Whole Slide test Images using the FROC curve. With the cost of one false positive, the best performing method, the one layer Gaussian process, identifies 83.87% (sensitivity) of all annotated cancer in the Whole Slide Image. This result corroborates the quality of the extracted features, no more than a layer is needed to achieve excellent generalization results. Conclusion Two new descriptors to extract morphological features from histological images have been proposed. They collect very relevant information for cancer detection. From these descriptors, shallow and deep Gaussian Processes are capable of extracting the complex structure of prostate histological images. The new space/descriptor/classifier paradigm outperforms state-of-art shallow classifiers. Furthermore, despite being much simpler, it is competitive to state-of-art CNN architectures both on the proposed SICAPv1 database and on an external databaseThis work was supported by the Ministerio de Economia y Competitividad through project DPI2016-77869. The Titan V used for this research was donated by the NVIDIA CorporationEsteban, AE.; López-Pérez, M.; Colomer, A.; Sales, MA.; Molina, R.; Naranjo Ornedo, V. (2019). A New Optical Density Granulometry-Based Descriptor for the Classification of Prostate Histological Images Using Shallow and Deep Gaussian Processes. Computer Methods and Programs in Biomedicine. 178:303-317. https://doi.org/10.1016/j.cmpb.2019.07.003S30331717

IAA : Información y actualidad astronómica (44)

Sumario : La importancia de los cometas.-- Gamow, Alpher y el ylem.-- DECONSTRUCCIÓN Y otros ENSAYOS. El universo molecular.-- EL “MOBY DICK” DE... Alberto Molino (IAG).-- CIENCIA EN HISTORIAS...Tras la estela de Plateau.-- ACTUALIDAD.-- SALA LIMPIA.-- CIENCIA: PILARES E INCERTIDUMBRES. Explosiones de rayos gamma.N

IAA : Información y actualidad astronómica (36)

Sumario : Púlsares: faros para navegantes cósmicos.-- Espectroscopía: leyendo entre líneas (II).-- Un universo acelerado.-- CIENCIA EN HISTORIAS. Margaret Burbidge.-- DECONSTRUCCIÓN Y otros ENSAYOS. Hola, soy Nikola.-- EL “MOBY DICK” DE... Cristina Rodríguez López (IAA-CSIC).-- ACTUALIDAD.-- ENTRE BASTIDORES.-- SALA LIMPIA.-- CIENCIA: PILARES E INCERTIDUMBRES. La Vía Láctea.-- AGENDA/RECOMENDADOS.--N

Wavelength-switchable L-band fiber laser assisted by random reflectors

A wavelength-switchable L-band erbium-doped fiber laser (EDFL) assisted by an artificially controlled backscattering (ACB) fiber reflector is here presented. This random reflector was inscribed by femtosecond (fs) laser direct writing on the axial axis of a multimode fiber with 50 um core and 125 um cladding with a length of 17 mm. This microstructure was placed inside a surgical syringe to be positioned in the center of a high-precision rotation mount to accurately control its angle of rotation. Only by rotating this mount, three different output spectra were obtained: a single wavelength lasing centered at 1574.75 nm, a dual wavelength lasing centered at 1574.75 nm and 1575.75 nm, and a single wavelength lasing centered at 1575.5 nm. All of them showed an optical signal-to-noise ratio (OSNR) of around 60 dB when pumped at 300 mW.This work was financed by the program “José Castillejo para estancias de movilidad en el extranjero de jóvenes doctores”, funded by the Ministerio de Universidades of Spain (reference CAS21/00351); the Spanish AEI projects PID2019-107270RB, funded by MCIN/AEI/10.13039/501100011033 and FEDER “A way to make Europe”, and projects PDC2021-121172 and TED2021-130378B funded by MCIN/ AEI/10.13039/501100011033 and European Union “Next generation EU”/PTR. Finally, the work was also founded by the Ministerio de Educación, Cultura y Deporte of Spain (PhD grant FPU2018/02797)

C and L band fiber lasers enhanced by ultrafast laser inscribed artificial backscatter reflectors

This letter presents an experimental comparison between two linear-cavity erbium-doped fiber lasers (EDFL) assisted by two different artificial backscatter fiber-based reflectors. Both reflectors were inscribed by femtosecond laser direct writing, one of them within a single-mode fiber (SMF) and the other one within a multi-mode fiber (MMF). Although the erbium-doped fiber amplifier (EDFA) used in both structures was the same and both reflectors were manufactured under the same parameters, the reflection spectrum of each was clearly different due to their different physical properties. The first linear-cavity EDFL, consisting of an SMF-based reflector with 9µm core and 125µm cladding, resulted in a single laser emission line located in the C-band and centered at 1564.4 nm, exhibiting an optical signal-to-noise ratio (OSNR) of 52dB when pumped at 100mW. On the other hand, a single laser emission line with a similar OSNR but in L-band (centered at 1574.5nm) was obtained when using an MMF-based reflector with 50µm core and 125µm cladding.Ministerio de Educación, Cultura y Deporte (PhD grant FPU2018/02797); European Commission (Next generation EU/PTR); FEDER (A way to make Europe); MCIN/AEI/10.13039/501100011033 (PDC2021-121172-C21, PID2019-107270RB)