Quasars Clustering at z approx 3 on Scales less sim 10 h^{-1} Mpc

We test the hypothesis whether high redshift QSOs would preferentially appear in small groups or pairs, and if they are associated with massive, young clusters. We carried out a photometric search for \Ly emitters on scales $\lesssim 10 h^{-1}$ Mpc, in the fields of a sample of 47 $z\approx3$ known QSOs. Wide and narrow band filter color-magnitude diagrams were generated for each of the $6'.6\times6'.6$ fields. A total of 13 non resolved objects with a significant color excess were detected as QSO candidates at a redshift similar to that of the target. All the candidates are significantly fainter than the reference QSOs, with only 2 of them within 2 magnitudes of the central object. Follow-up spectroscopic observations have shown that 5, i.e., about 40% of the candidates, are QSOs at the same redshift of the target; 4 are QSOs at different z (two of them probably being a lensed pair at z = 1.47); 2 candidates are unresolved HII galaxies at z$\sim$0.3; one unclassified and one candidate turned out to be a CCD flaw. These data indicate that at least 10% of the QSOs at z$\sim$3 do have companions. We have also detected a number of resolved, rather bright \Ly Emitter Candidates. Most probably a large fraction of them might be bright galaxies with [OII] emission, at z$\approx$ 0.3. The fainter population of our candidates corresponds to the current expectations. Thus, there are no strong indication for the existence of an overdensity of \Ly galaxies brighter than m $\approx$ 25 around QSOs at $z\approx$ 3.Comment: 29 pages, 8 figures, tar gzip LaTex file, accepted to appear in Ap

Effects of epitaxial strain on the growth mechanism of YBa2Cu3O7-x thin films in [YBa2Cu3O7-x / PrBa2Cu3O7-x] superlattices

We report on the growth mechanism of YBa2Cu3O7-x (YBCO). Our study is based on the analysis of ultrathin, YBa2Cu3O7-x layers in c-axis oriented YBa2Cu3O7-x / PrBa2Cu3O7-x superlattices. We have found that the release of epitaxial strain in very thin YBCO layers triggers a change in the dimensionality of the growth mode. Ultrathin, epitaxially strained, YBCO layers with thickness below 3 unit cells grow in a block by block two dimensional mode coherent over large lateral distances. Meanwhile, when thickness increases, and the strain relaxes, layer growth turns into three dimensional, resulting in rougher layers and interfaces.Comment: 10 pages + 9 figures, accepted in Phys. Rev.

Riscos genéticos da produção de híbridos de peixes nativos.

A produção de peixes nativos e seus híbridos chama a atenção daqueles que observam o Brasil como alvo de investimentos agropecuários e futura potência da aquicultura mundial. Dada a competitividade e dinamismo, o mercado aquícola nacional tem motivado a produção de híbridos em maior escala nos últimos anos, buscando neles características favoráveis de ganho de peso, resistência ao frio, rusticidade e adaptação à alimentação artificial. Por outro lado, a mistura de animais híbridos sobre as linhagens puras e o seu escape inadvertido para os ambientes naturais certamente expõe a sustentabilidade da aquicultura. Sendo assim, este documento buscou reunir informações sobre a produção, impacto genético, riscos e desafios do cultivo de híbridos frente ao desafio de equilibrar a conservação da biodiversidade com a produção sustentável de alimentos.bitstream/item/131431/1/cnpasadoc3.pd

Towards Autopoietic Computing

A key challenge in modern computing is to develop systems that address complex, dynamic problems in a scalable and efficient way, because the increasing complexity of software makes designing and maintaining efficient and flexible systems increasingly difficult. Biological systems are thought to possess robust, scalable processing paradigms that can automatically manage complex, dynamic problem spaces, possessing several properties that may be useful in computer systems. The biological properties of self-organisation, self-replication, self-management, and scalability are addressed in an interesting way by autopoiesis, a descriptive theory of the cell founded on the concept of a system's circular organisation to define its boundary with its environment. In this paper, therefore, we review the main concepts of autopoiesis and then discuss how they could be related to fundamental concepts and theories of computation. The paper is conceptual in nature and the emphasis is on the review of other people's work in this area as part of a longer-term strategy to develop a formal theory of autopoietic computing.Comment: 10 Pages, 3 figure

Broodstock management: cryopreservation parameters to select native tropical fish.

Genetic management of broodstock aims to produce fingerlings of superior quality from the adoption of practices and technological processes that assist in the control of the breeders. For this effective control, the fish farmer must avoid matings that would yield inbreeding and select the best breeders by the sperm quality

Análise fatorial aplicada em sistemas agroflorestais e sistemas de produção tradicionais. Tomé-Açu, Pará, 2001 a 2003.

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Correlation entropy of synaptic input-output dynamics

The responses of synapses in the neocortex show highly stochastic and nonlinear behavior. The microscopic dynamics underlying this behavior, and its computational consequences during natural patterns of synaptic input, are not explained by conventional macroscopic models of deterministic ensemble mean dynamics. Here, we introduce the correlation entropy of the synaptic input-output map as a measure of synaptic reliability which explicitly includes the microscopic dynamics. Applying this to experimental data, we find that cortical synapses show a low-dimensional chaos driven by the natural input pattern.Comment: 7 pages, 6 Figures (7 figure files

Extracting Hα\alpha flux from photometric data in the J-PLUS survey

We present the main steps that will be taken to extract H$\alpha$ emission flux from Javalambre Photometric Local Universe Survey (J-PLUS) photometric data. For galaxies with $z\lesssim0.015$, the H$\alpha$+[NII] emission is covered by the J-PLUS narrow-band filter $F660$. We explore three different methods to extract the H$\alpha$ + [NII] flux from J-PLUS photometric data: a combination of a broad-band and a narrow-band filter ($r'$ and $F660$), two broad-band and a narrow-band one ($r'$, $i'$ and $F660$), and a SED-fitting based method using 8 photometric points. To test these methodologies, we simulated J-PLUS data from a sample of 7511 SDSS spectra with measured H$\alpha$ flux. Based on the same sample, we derive two empirical relations to correct the derived H$\alpha$+[NII] flux from dust extinction and [NII] contamination. We find that the only unbiased method is the SED fitting based one. The combination of two filters underestimates the measurements of the H$\alpha$ + [NII] flux by a 28%, while the three filters method by a 9%. We study the error budget of the SED-fitting based method and find that, in addition to the photometric error, our measurements have a systematic uncertainty of a 4.3%. Several sources contribute to this uncertainty: differences between our measurement procedure and the one used to derive the spectroscopic values, the use of simple stellar populations as templates, and the intrinsic errors of the spectra, which were not taken into account. Apart from that, the empirical corrections for dust extinction and [NII] contamination add an extra uncertainty of 14%. Given the J-PLUS photometric system, the best methodology to extract H$\alpha$ + [NII] flux is the SED-fitting based one. Using this method, we are able to recover reliable H$\alpha$ fluxes for thousands of nearby galaxies in a robust and homogeneous way.Comment: 11 pages, 14 figures. Minor changes to match the published versio

Green spaces in a tertiary care children`s hospital benefits, taxonomic survey, and perspective

El contacto del ser humano con espacios verdes naturales tiene un efecto físico, mental y social beneficioso. Con el primer objetivo de conocer las especies vegetales de los jardines del Hospital de Pediatría Garrahan (Ciudad de Buenos Aires), se realizó un relevamiento taxonómico entre diciembre de 2013 y noviembre de 2016. Otro objetivo fue revisar el estado del conocimiento sobre cómo los espacios verdes naturales influían en la salud de los pacientes internados. Existen sesenta y nueve especies de plantas que abarcan cuarenta y siete familias botánicas; de ellas, solo el ocho por ciento son nativas. Se sugiere incrementar las especies autóctonas y coordinar aspectos relacionados con su preservación. Este relevamiento, como parte de un plan que incluirá la divulgación del conocimiento, comprensión y concientización sobre espacios verdes y salud, y la cuantificación de esos efectos concretos en este Hospital, profundizará y fomentará la interacción de los pacientes, los familiares y los profesionales con los espacios verdes naturalesHumans coming in contact with natural green spaces experience beneficial physical, mental, and social effects. For the primary purpose of describing plant species found in the gardens of Hospital de Pediatría “Prof. Dr. Juan P. Garrahan” (Autonomous City of Buenos Aires), a taxonomic survey was carried out between December 2013 and November 2016. A secondary objective was to review the extent of knowledge on how natural green spaces affect the health of hospitalized patients. There are 69 plant species from 47 botanical families; of these, only 8% are native. The recommendation is to increase the number of native species and coordinate those aspects related to their preservation. This survey, which is part of a plan that will include the dissemination of knowledge, understanding and awareness of green spaces and health, and the quantification of such specific effects in this hospital, will deepen and promote the interaction of patients, families, and health care providers with natural green spaces.Inst. de Recursos BiológicosFil: Caceres Guido, P. Hospital de Pediatría. S.A.M.I.C. “Prof. Dr. Juan P.Garrahan”. Grupo de Medicina Integradora; ArgentinaFil: Varela, Beatriz G. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Cátedra de Farmacobotánica; ArgentinaFil: Bach, Hernán Gerónimo. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Cátedra de Farmacobotánica; Argentina. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos; ArgentinaFil: Balbarrey, Ziomara. Hospital de Pediatría. S.A.M.I.C. “Prof. Dr. Juan P.Garrahan”. Grupo de Medicina Integradora; ArgentinaFil: Wagner, Marcelo L. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Cátedra de Farmacobotánica; Argentin