Educación Musical Escolar en las Américas: Condiciones, Prácticas, y Políticas desde una Perspectiva Socio-Ecológica

La educación musical formal está presente en un gran número de escuelas primarias y secundarias a lo largo de las Américas, aunque tanto las políticas educativas, planes de estudios y su implementación varían según regiones, estados e instituciones educativas. El conocimiento de las condiciones actuales de la educación musical en un hemisferio, cada vez más interconectado e interdependiente, podría ofrecer ideas para resolver desafíos de acceso, igualdad, y equidad hacia una educación artística de calidad. Este artículo ha sido escrito para proporcionar una sintaxis general, no exhaustiva, de la investigación sobre programas y políticas de música escolar a lo largo de las Américas. Más específicamente, dentro de un marco socioeconómico, hemos tratado de determinar de qué manera factores externos afectan las prácticas docentes así como el impacto de los docentes de aula en estas fuerzas. Se espera que esta examinación ofrezca ideas a quienes elaboran y promueven políticas educativas en artes, para asegurar que los estudiantes tengan igualdad de oportunidades y acceso a una educación musical escolar de calidad

Distribution of phytoplankton pigments in nine European estuaries and implications for an estuarine typology

Phytoplankton pigments were studied by LiquidChromatography (HPLC) in nine West Europeanestuaries. Three estuaries, i.e. the Rhine,Scheldt and the Gironde were sampled four timesto cover the different seasons, whereas theother six estuaries were sampled once. Pigmentdistributions in estuaries reflect bothriverine inputs as well as autochthonousblooms. Fucoxanthin was the most commonaccessory photosynthetic pigment showing thatDiatoms were the most common group in thestudied estuaries and were particularlydominant during autumn and winter. In the veryturbid Gironde estuary, degradation processeswere predominant between salinities 1 and 20,while Diatoms, Dinoflagellates and Cryptophytesbloomed above 20 salinity during spring andsummer. This contrasted with the highlyeutrophic but less turbid Scheldt, wherephytoplanktonic blooms occurred at lowsalinities close to the city of Antwerp. In theScheldt, we observed both a tenfold fluctuationof phytoplankton biomass and a fluctuatingpigment diversity index. In contrast,chlorophyll a was always low in theGironde, but we observed large variations ofpigment diversity among samplings duringdifferent seasons. Distribution of pheopigmentsshowed that the maximum turbidity zone (MTZ)was a highly reactive region for heterotrophicphytoplankton degradation. The Scheldt and theThames were the most anthropogenic influencedestuaries contrasting with the Gironde estuarythat has a less urbanised watershed. Anestuarine typology is proposed based on threeclusters emerging from a correspondenceanalysis of pigment variables and variablescharacterising the anthropogenic impact andphysical forcing

Energy Deposition around Swift Carbon-Ion Tracks in Liquid Water

Energetic carbon ions are promising projectiles used for cancer radiotherapy. A thorough knowledge of how the energy of these ions is deposited in biological media (mainly composed of liquid water) is required. This can be attained by means of detailed computer simulations, both macroscopically (relevant for appropriately delivering the dose) and at the nanoscale (important for determining the inflicted radiobiological damage). The energy lost per unit path length (i.e., the so-called stopping power) of carbon ions is here theoretically calculated within the dielectric formalism from the excitation spectrum of liquid water obtained from two complementary approaches (one relying on an optical-data model and the other exclusively on ab initio calculations). In addition, the energy carried at the nanometre scale by the generated secondary electrons around the ion's path is simulated by means of a detailed Monte Carlo code. For this purpose, we use the ion and electron cross sections calculated by means of state-of-the art approaches suited to take into account the condensed-phase nature of the liquid water target. As a result of these simulations, the radial dose around the ion's path is obtained, as well as the distributions of clustered events in nanometric volumes similar to the dimensions of DNA convolutions, contributing to the biological damage for carbon ions in a wide energy range, covering from the plateau to the maximum of the Bragg peak

Planarians as a model to assess in vivo the role of matrix metalloproteinase genes during homeostasis and regeneration

Matrix metalloproteinases (MMPs) are major executors of extracellular matrix remodeling and, consequently, play key roles in the response of cells to their microenvironment. The experimentally accessible stem cell population and the robust regenerative capabilities of planarians offer an ideal model to study how modulation of the proteolytic system in the extracellular environment affects cell behavior in vivo. Genome-wide identification of Schmidtea mediterranea MMPs reveals that planarians possess four mmp-like genes. Two of them (mmp1 and mmp2) are strongly expressed in a subset of secretory cells and encode putative matrilysins. The other genes (mt-mmpA and mt-mmpB) are widely expressed in postmitotic cells and appear structurally related to membrane-type MMPs. These genes are conserved in the planarian Dugesia japonica. Here we explore the role of the planarian mmp genes by RNA interference (RNAi) during tissue homeostasis and regeneration. Our analyses identify essential functions for two of them. Following inhibition of mmp1 planarians display dramatic disruption of tissues architecture and significant decrease in cell death. These results suggest that mmp1 controls tissue turnover, modulating survival of postmitotic cells. Unexpectedly, the ability to regenerate is unaffected by mmp1(RNAi). Silencing of mt-mmpA alters tissue integrity and delays blastema growth, without affecting proliferation of stem cells. Our data support the possibility that the activity of this protease modulates cell migration and regulates anoikis, with a consequent pivotal role in tissue homeostasis and regeneration. Our data provide evidence of the involvement of specific MMPs in tissue homeostasis and regeneration and demonstrate that the behavior of planarian stem cells is critically dependent on the microenvironment surrounding these cells. Studying MMPs function in the planarian model provides evidence on how individual proteases work in vivo in adult tissues. These results have high potential to generate significant information for development of regenerative and anti cancer therapies

Energy loss of H+ and H2+ beams in carbon nanotubes: a joint experimental and simulation study

Carbon nanotube properties can be modified by ion irradiation; therefore it is important to know the manner in which ions deposit energy (how much and where) in the nanotubes. In this work, we have studied, experimentally and with a simulation code, the irradiation of multi-walled carbon nanotubes (MWCNT), supported on a holey amorphous carbon (a-C) substrate, with low energy (2–10 keV/u) H+ and H2+ molecular beams, impinging perpendicularly to the MWCNT axis. The energy distribution of protons traversing the nanotubes (either from the H+ beam or dissociated from the H2+ beam) was measured by the transmission technique in the forward direction. Two well-differentiated peaks appear in the experimental energy-loss distribution of the fragments dissociated from the molecular H2+ beam, in correspondence to the ones detected with the proton beam. One is the low-energy loss peak (LELP), which has a symmetric width; the other is the high-energy loss peak (HELP), which shows an asymmetric broadening towards larger energy loss than the corresponding proton energy distribution. A semi-classical simulation, accounting for the main interaction processes (both elastic and inelastic), of the proton trajectories through the nanotube and the supporting substrate has been done, in order to elucidate the origin of these structures in the energy spectra. Regarding the H+ energy spectrum, the LELP corresponds to projectiles that travel in quasi-channelling motion through the most outer walls of the nanotubes and then pass through the substrate holes, whereas the HELP results mostly from projectiles traversing only the a-C substrate, with the asymmetry broadening being due to a minor contribution of those protons that cross the a-C substrate after exiting the nanotube. The broadening of the peaks corresponding to dissociated fragments, with respect to that of the isolated protons, is the result of vicinage effects between the fragments, when travelling in quasi-channelling conditions through the outer layers of the nanotube, and Coulomb explosion just after exiting the target. The excellent agreement between the measured and the simulated energy spectra of the H+ beam validates our simulation code in order to predict the energy deposited by ion beams in carbon nanotubes.This work has been financially supported by Fondecyt 1100759, Fondecyt 1121203 and USM-DGIP 11.11.11, Anillo ACT1108, Proyecto Basal FB0821 - CONICYT, the Spanish Ministerio de Economía y Competitividad and European Regional Development Fund (Projects FIS2014-58849-P and PGC2018-096788-B-I00), and Fundación Séneca (Project No. 19907/GERM/15)

21 de setiembre: día de la ciencia y la técnica

Con motivo del 3O aniversario de la instauración del 21 de setiembre como día de la Ciencia y la Técnica en la Provincia de Buenos Aires, la CIC le ha solicitado a un grupo selecto de científicos, su opinión sobre aspectos esenciales del quehacer científico y tecnológico. El presente texto contiene los siguientes trabajos: - Consideraciones acerca de la investigacion técnico-científica sobre materiales, por Eduardo R. Abril. - Ciencia y tecnología de alimentos, por Pedro Cattáneo - Ciencia y tecnología en química orgánica por Venancio Deulofeu. - Ciencia y tecnología - recursos humanos por Ernesto E. Galloni. - Discurso de apertura de la reunion sobre ciencia y tecnologia realizada en Mar del Plata del 6 al 8 de julio de 1978 por Luis F. Leloir. - Incidencia de la investigación en el desarrollo de la metalurgia por Roberto F. Recoder. - Importancia de la investigación matemática en la sociedad contemporánea por Luis A. Santaló. - La investigación en fisicoquímica y su proyección en el desarrollo científico y tecnológico por Hans J. Schumacher

The CMS Event Builder

The data acquisition system of the CMS experiment at the Large Hadron Collider will employ an event builder which will combine data from about 500 data sources into full events at an aggregate throughput of 100 GByte/s. Several architectures and switch technologies have been evaluated for the DAQ Technical Design Report by measurements with test benches and by simulation. This paper describes studies of an EVB test-bench based on 64 PCs acting as data sources and data consumers and employing both Gigabit Ethernet and Myrinet technologies as the interconnect. In the case of Ethernet, protocols based on Layer-2 frames and on TCP/IP are evaluated. Results from ongoing studies, including measurements on throughput and scaling are presented. The architecture of the baseline CMS event builder will be outlined. The event builder is organised into two stages with intelligent buffers in between. The first stage contains 64 switches performing a first level of data concentration by building super-fragments from fragments of 8 data sources. The second stage combines the 64 super-fragments into full events. This architecture allows installation of the second stage of the event builder in steps, with the overall throughput scaling linearly with the number of switches in the second stage. Possible implementations of the components of the event builder are discussed and the expected performance of the full event builder is outlined.Comment: Conference CHEP0