310 research outputs found

    Comparing teacher and student perspectives regarding the use of L1 in EFL chilean high school classrooms

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    Tesis (Profesor de Inglés para la Enseñanza Básica y Media y al grado académico de Licenciado en Educación)In the Chilean context, English teachers are commanded to perform one hundred percent English classes, but unfortunately, this is not accomplished in every context; hence, this study decided to explore and compare teachers’ and students’ perspectives regarding the use of L1 in the EFL Chilean high school classroom. A quantitative instrument was applied to a total population of 510 being both teachers and students from different districts of Santiago. The results obtained in this study portrayed that both teachers and students agreed on the L1 usage under different situations, these ranging from grammar explanation lessons to managing discipline

    O grande arco de Teach For America: A análise textual da obra de Wendy Kopp usando a teoria racial crítica

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    We read and analyzed 165,000 words and uncover a series of counter-stories buried within a textual corpus, authored by Teach For America (TFA) founder Wendy Kopp (Kopp, 1989, 2001; Kopp Farr, 2011), that offers insight into the forms of racism endemic to Teach For America. All three counter-stories align with a critical race theory (CRT) framework.  Specifically, we answer the following questions:  What evidence of institutional and epistemological racism is exposed by a CRT textual analysis of TFA’s founding document and later works by Wendy Kopp?  To what extent has TFA appropriated the language of culturally relevant pedagogy, while advancing an uninterrogated neoliberal ideology? And, to what extent does TFA’s contribution to a “culture of achievement” (Kopp Farr, 2011) constitute an actual “poverty of culture” (Ladson-Billings, 2006a) that enacts real harms on communities of color? Leímos y analizamos 165.000 palabras escritas por Wendy Kopp (Kopp, 1989, 2001; Kopp y Farr, 2011) la fundadora de Teach For America (TFA) y descubrimos una serie de contra-historias enterradas dentro de un corpus textual, que ofrecen información sobre formas de racismo endémicas en Teach For America. Tres contra-relatos se alinean con el marco de la teoría crítica de la raza (CRT). Específicamente, respondemos a las siguientes preguntas: ¿Qué evidencia de racismo institucional y epistemológico se exponen por un análisis textual CRT del documento fundacional de TFA y obras de Wendy Kopp? ¿Hasta qué punto TFA se ha apropiado del lenguaje de la pedagogía culturalmente relevante, mientras se avanza una ideología neoliberal sin interrogarla? Y, ¿en qué medida la contribución de TFA a una "cultura del logro" (Kopp y Farr, 2011) constituyen un "empobrecimiento cultural" (Ladson-Billings, 2006a), que permite daños reales en comunidades de color?Lemos e analisamos 165.000 palavras escritas por Wendy Kopp (Kopp, 1989, 2001; Kopp e Farr, 2011) a fundadora do Teach For America (TFA) e descobrimos uma série de contra-narrativas enterradas dentro de um corpus, que oferece informações sobre as formas de racismo endêmico em Teach For America. Três contra-narrativas se alinham com o marco conceitual da teoria racial crítica (CRT). Especificamente, respondemos às seguintes perguntas: Que evidência do racismo institucional e epistemológico é exposta por uma análise textual usando CRT do documento de fundação do TFA e obras posteriores de Wendy Kopp? Até que ponto TFA se apropriou da linguagem da pedagogia culturalmente relevante, promovendo ao mesmo tempo uma ideologia neoliberal? E, em que medida a contribuição de TFA a uma "cultura do logro" (Kopp e Farr, 2011) constitue um "empobrecimento cultural" (Ladson-Billings, 2006a), que resulta em danos reais nas comunidades de cor

    On the use of sniffers for spectrum occupancy measurements of Bluetooth low energy primary channels

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    The methods usually employed to measure channel occupancy show limitations in the context of Bluetooth Low Energy (BLE) advertisements. We propose and analyze the use of BLE sniffers as light and portable low-cost spectrum occupancy meters to be used in scenarios where real time signal analyzers are not adequate. For the measurement technique to be successful, several low-level effects must be considered. The paper argues about on-air time, receiving blind times due to processing and intra system interference, buffer saturation and frequency anchoring. Hence, a compensation procedure based on collision rate estimation is proposed. Results with the refined method show that occupancies of 40% can be measured with an overestimation error whose percentile 95% is 5 percentage points. This is reduced to 1.9 points when the occupancy is 15%. The sniffers perform in real time and are shown to correctly track short term load variations. The strategy has been successfully used to characterize occupancy in highly variable and loaded scenarios such as subway platforms and a shopping mall. Values up to 25% have been observed, which implies a relevant packet error rate. Hence, the tool can be used to make agile audits and configure the parameters that control communication redundancy in new or existing networks.The work by UPC has been funded by MCIN/ AEI /10.13039/501100011033 and by ERDF A way of making Europe, with the grant RTI2018-099880-B-C32 and PID2021-125799OA-I00. The work by I3A-UZ has been funded by MCIN/ AEI /10.13039/501100011033 and by ERDF A way of making Europe, with the grants RTI2018-095684-B-I00 and RTI2018-099063-B-I00, and by the Government of Aragon (Reference Group T31 20R).Peer ReviewedPostprint (published version

    zoolog R package: Zooarchaeological analysis with log-ratios

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    Log Size Indexes (LSI) allow the increase of the number of data and have been used in a number of zooarchaeological studies since 1950. However, some standards to calculate the log ratios remain unpublished, the calculation of the indexes can be tedious, and it is further hindered by the diversity of data recording practices. The R package ‘zoolog’ enables calculation of thousands of log-ratios in seconds, with the advantage that the users can choose between different public references, which increases the repeatability and comparability of the results, allowing the smooth integration of references and databases with heterogeneous nomenclatures. Alternatively, the users may use their own references. This paper presents the main functionalities and procedures enabled by the package ‘zoolog’, together with some examples of use. A real dataset and several examples with R code are provided with the aim of facilitating osteometrical analyses in zooarchaeology.This work was developed as part of the ERC-Starting Grant ZooMWest (Grant agreement 716298)

    A low-cost tracking system for running race applications based on bluetooth low energy technology

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    Timing points used in running races and other competition events are generally based on radio-frequency identification (RFID) technology. Athletes’ times are calculated via passive RFID tags and reader kits. Specifically, the reader infrastructure needed is complex and requires the deployment of a mat or ramps which hide the receiver antennae under them. Moreover, with the employed tags, it is not possible to transmit additional and dynamic information such as pulse or oximetry monitoring, alarms, etc. In this paper we present a system based on two low complex schemes allowed in Bluetooth Low Energy (BLE): the non-connectable undirected advertisement process and a modified version of scannable undirected advertisement process using the new capabilities present in Bluetooth 5. After fully describing the system architecture, which allows full real-time position monitoring of the runners using mobile phones on the organizer side and BLE sensors on the participants’ side, we derive the mobility patterns of runners and capacity requirements, which are determinant for evaluating the performance of the proposed system. They have been obtained from the analysis of the real data measured in the last Barcelona Marathon. By means of simulations, we demonstrate that, even under disadvantageous conditions (50% error ratio), both schemes perform reliably and are able to detect the 100% of the participants in all the cases. The cell coverage of the system needs to be adjusted when non-connectable process is considered. Nevertheless, through simulation and experimental, we show that the proposed scheme based on the new events available in Bluetooth 5 is clearly the best implementation alternative for all the cases, no matter the coverage area and the runner speed. The proposal widely exceeds the detection requirements of the real scenario, surpassing the measured peaks of 20 sensors per second incoming in the coverage area, moving at speeds that range from 1.5 m/s to 6.25 m/s. The designed real test-bed shows that the scheme is able to detect 72 sensors below 600 ms, fulfilling comfortably the requirements determined for the intended application. The main disadvantage of this system would be that the sensors are active, but we have proved that its consumption can be so low (9.5 µA) that, with a typical button cell, the sensor battery life would be over 10,000 h of use.Peer ReviewedPostprint (published version

    Bluetooth Low Energy sensor networks for railway applications

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    ©2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.This paper analyzes the viability of Bluetooth Low Energy (BLE) as the enabling technology in railway scenarios to allow sensor data transmission from ground to train. This proposal is based on using the broadcasting capabilities introduced by the Bluetooth specifications since v4.0. The last version, v5.0, extends the range the speed and the broadcast capacity. However, due to its recent publication it is hard to find real devices with it implemented in the market. The proposed schema has been validated by means of experimental measurements using v4.2.Peer ReviewedPostprint (author's final draft

    Dissecting the microglial response in transgenic models of amyloidogenesis and tauopathy

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    Amyloid-beta (Abeta) peptide deposits and hyperphosphorylated tau protein (phospho-tau) accumulate in Alzheimer’s disease (AD) brains. These abnormal protein aggregates leads to glial activation, synaptic dysfunction, neuronal loss and cognitive decline. While microglial response has mostly been analyzed in relation to Abeta accumulation, little is still known about inflammatory processes associated with tau pathology. Microglial reactivity and defective glial responses have been involved in these proteinopathies. Our aim is to clarify the effects of Abeta and tau separately, in order to improve the comprehension of their differential contribution to neuroinflammation and neurodegeneration. We compared the progression of these processes in an amyloidogenic AD model (APPSL/PS1M146L) and two different models of tauopathy (ThyTau22 and hP301S) from 2 to 18 months of age. Accumulation of aggregated proteins was assessed using specific anti- Abeta and phospho-tau antibodies. Inflammatory response was studied using a battery of microglial markers (Iba1, CD45, CD68, Trem2 and Gal-3). In the hippocampus of these models, Tau and Abeta pathologies initiated as early as 2 months of age and increased progressively with aging. Neuritic plaques induced a strong microglial activation associated to plaques in APP/PS1 mice. Interestingly, inflammatory markers and microglial reactivity were barely increased in the hippocampus of ThyTau mice in contrast to not only APP/PS1, but also to P301S mice, which displayed a prominent microglial response. Deciphering the specific effects of Abeta, tau and their different toxic species, would indeed enable the development of novel therapeutic strategies and drugs targeting neuroinflammatory pathways related to these proteinopathies.Universidad de Málaga. Campus de excelencia Andalucía-Tech. Supported by PI18/01557 (AG) and PI18/01556 (JV) grants from ISCiii of Spain co-financed by FEDER funds from European Union, and by grant PPIT.UMA.B1.2017/26 (RS-V)

    Proposal and evaluation of BLE discovery process based on new features of bluetooth 5.0

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    The device discovery process is one of the most crucial aspects in real deployments of sensor networks. Recently, several works have analyzed the topic of Bluetooth Low Energy (BLE) device discovery through analytical or simulation models limited to version 4.x. Non-connectable and non-scannable undirected advertising has been shown to be a reliable alternative for discovering a high number of devices in a relatively short time period. However, new features of Bluetooth 5.0 allow us to define a variant on the device discovery process, based on BLE scannable undirected advertising events, which results in higher discovering capacities and also lower power consumption. In order to characterize this new device discovery process, we experimentally model the real device behavior of BLE scannable undirected advertising events. Non-detection packet probability, discovery probability, and discovery latency for a varying number of devices and parameters are compared by simulations and experimental measurements. We demonstrate that our proposal outperforms previous works, diminishing the discovery time and increasing the potential user device density. A mathematical model is also developed in order to easily obtain a measure of the potential capacity in high density scenarios.Peer ReviewedPostprint (published version

    Cancro resinoso del pino: ¿una amenaza potencial para las plantaciones de Pinus radiata en Chile?

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    Fusarium circinatum is the fungus that causes the disease “canker” (pitch canker), which affects many species of conifers. This review describes the state of the art of F. circinatum worldwide and the current situation in Chile, covering the history of the pathogen and the disease. In Chile, the pathogen was detected in Pinus radiata hedges in late 2001, being present today in 39 of 196 nurseries, located between the regions of O’Higgins and Los Ríos. After 14 years of the detection of F. circinatum, the pathogen has not attacked commercial plantations of P. radiata. Measures for integrated disease management, where genetic resistance constitutes the main strategy in a scenario in which pitch canker could appear in commercial plantations of P. radiata in Chile.Fusarium circinatum es el hongo causante de la enfermedad “cancro resinoso” (pitch canker), que afecta numerosas especies de coníferas. En esta revisión se describe el estado del arte de F. circinatum a nivel mundial y su situación actual en Chile, abarcando antecedentes del patógeno y de la enfermedad. En Chile, el patógeno fue detectado en setos de Pinus radiata a fines de 2001, encontrándose hoy presente en 39 viveros de un total de 196, ubicados entre las regiones de O’Higgins y de Los Ríos. Después de 14 años de la detección de F. circinatum en Chile, el patógeno no ha presentado diseminación en las plantaciones comerciales de P. radiata. Se destacan las medidas para el manejo integrado de la enfermedad, donde la resistencia genética sería la principal estrategia ante un escenario en que el cancro resinoso se presente en las plantaciones comerciales de P. radiata en Chile
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