3,182 research outputs found
The Impact of Basic Education Reform on the Educational Participation of 16 to 17-year-old Youth in the Philippines
The study measures the impact on the school participation of 16 to 17-year-old learners in the Philippines of the implementation of the Senior High School program (SHS), which came into full effect in school year 2017–2018. The SHS program, which extended secondary education in the country from four to six years, was the most ambitious education reform action in the country in recent memory. The study found that the SHS program resulted in an increase in overall school participation rate of at least 13 percentage points among 16 to 17-year-olds. Perhaps more importantly, the increase in school participation rate was found to be highly progressive with those 16 to 17-year-olds in the two bottom income quintiles experiencing the highest increase in school participation rates by a wide margin. The study also found that both male and female students benefited from the program, although the gains appear to be higher for female students. Most of the gains in school participation were also found to occur outside Metro Manila
Theoretical Foundation of Copernicus: A Unified System for Trajectory Design and Optimization
The fundamental methods are described for the general spacecraft trajectory design and optimization software system called Copernicus. The methods rely on a unified framework that is used to model, design, and optimize spacecraft trajectories that may operate in complex gravitational force fields, use multiple propulsion systems, and involve multiple spacecraft. The trajectory model, with its associated equations of motion and maneuver models, are discussed
Using search queries for malaria surveillance, Thailand
Background: Internet search query trends have been shown to correlate with incidence trends for select infectious diseases and countries. Herein, the first use of Google search queries for malaria surveillance is investigated. The research focuses on Thailand where real-time malaria surveillance is crucial as malaria is re-emerging and developing resistance to pharmaceuticals in the region. Methods: Official Thai malaria case data was acquired from the World Health Organization (WHO) from 2005 to 2009. Using Google correlate, an openly available online tool, and by surveying Thai physicians, search queries potentially related to malaria prevalence were identified. Four linear regression models were built from different sub-sets of malaria-related queries to be used in future predictions. The models’ accuracies were evaluated by their ability to predict the malaria outbreak in 2009, their correlation with the entire available malaria case data, and by Akaike information criterion (AIC). Results: Each model captured the bulk of the variability in officially reported malaria incidence. Correlation in the validation set ranged from 0.75 to 0.92 and AIC values ranged from 808 to 586 for the models. While models using malaria-related and general health terms were successful, one model using only microscopy-related terms obtained equally high correlations to malaria case data trends. The model built strictly of queries provided by Thai physicians was the only one that consistently captured the well-documented second seasonal malaria peak in Thailand. Conclusions: Models built from Google search queries were able to adequately estimate malaria activity trends in Thailand, from 2005–2010, according to official malaria case counts reported by WHO. While presenting their own limitations, these search queries may be valid real-time indicators of malaria incidence in the population, as correlations were on par with those of related studies for other infectious diseases. Additionally, this methodology provides a cost-effective description of malaria prevalence that can act as a complement to traditional public health surveillance. This and future studies will continue to identify ways to leverage web-based data to improve public health
The southernmost evidence for an interglacial transgression (Sangamon?) in South America. First record of upraised Pleistocene marine deposits in Isla Navarino (Beagle Channel, Southern Chile)
Marine beach shell deposits recording a pre-Holocene marine transgression have been found at the southern shore of the Beagle Channel, Isla Navarino, Chile. These shelly deposits were dated by AMS at 41,700 14C years B.P., which clearly indicates a Pleistocene age. A sample of wood underlying the marine deposits yielded an infinite age (gt;46.1 14C ka B.P.). If the date on the shells is considered as a minimum, infinite age, together with the elevation of these marine units above present mean tide sea level (at least 10 m a.s.l.) they may be considered as deposited during the Last Interglacial, of Sangamon age (Marine Isotope Stage -MIS- 5e) or during a younger phase of MIS 5. The fossil content of this unit is similar to the fauna living in this region today, supporting also an Interglacial palaeoenvironment interpretation. If this interpretation and the dating proposal are correct, this is the first reported record of Sangamon deposits in the Beagle Channel and the southernmost Last Interglacial site (MIS 5) in South America
Bio-Inspired Design of Lightweight and Protective Structures
Biologically inspired designs have become evident and proved to be innovative and efficacious throughout the history. This paper introduces a bio-inspired design of protective structures that is lightweight and provides outstanding crashworthiness indicators. In the proposed approach, the protective function of the vehicle structure is matched to the protective capabilities of natural structures such as the fruit peel (e.g., pomelo), abdominal armors (e.g., mantis shrimp), bones (e.g., ribcage and woodpecker skull), as well as other natural protective structures with analogous protective functions include skin and cartilage as well as hooves, antlers, and horns, which are tough, resilient, lightweight, and functionally adapted to withstand repetitive high-energy impact loads. This paper illustrates a methodology to integrate designs inspired by nature, Topology optimization, and conventional modeling tools. Two designs are explained to support this methodology: Helmet design inspired by human bone cellular structure (trabecular structure) and vehicle body inspired by a water droplet, ribcage, and human bone. In the helmet design, a finite part of is optimized using topology optimization to generate the porous structure. In the vehicle body design, a water droplet framework, the bio-inspired simulation-based design algorithm used in this work generates innovative layouts. At the vehicle scale, the generated spaceframe has a structure similar to the one of a long bone. In essence, the aerodynamic water droplet shape is protected by the specialized ribcage. At the component scale, each spaceframe tubular component is filled with a functionally graded cellular structure. This internal cellular structure reminds the one of a bone. The spaceframe is attainable with few parts of greater complexity. Such complex, lightweight, multiscale structural layout can be manufactured using 3D printing technologies
Interface layer to improve polystyrene attachment on a quartz crystal resonator
Se describe el empleo de técnicas de formación de pelÃculas tendientes a mejorar el funcionamiento de un resonador
de cristal de cuarzo (QCR); dichas tecnologÃas fueron, por ejemplo, preparaciones de recubrimiento mediante
los métodos de spin y Langmuir-Blodgett (LB). La uniformidad y homogeneidad de la pelÃcula sobre el cristal de cuarzo
es fundamental para las aplicaciones que tiene un resonador como sensor quÃmico y biológico.
Se formaron pelÃculas de poliestireno (PS) y de cloruro de polivinilo (PVC) en solventes como ciclohexanona,
tetrahidrofurano (THF), dimetilformamida y cloroformo a diferentes concentraciones, usando el procedimiento de cubrimiento
por spin en soportes corrugados tipo wafer. La calidad de las pelÃculas fue determinada usando microscopÃa
óptica, elipsometrÃa y perfilometrÃa. Además, se prepararon pelÃculas en soportes corrugados y en QRC con superficie de oro por irrigación de la mencionada
sustancia en una subfase acuosa y transfiriéndola por impregnación de la superficie de subfase en el soporte.
Para la preparación de la pelÃcula LB se empleó ácido araquÃdico y partÃculas de PS. Las preparaciones de pelÃculas
de monocapa y multicapa de estas sustancias en soportes corrugados o en superficies de cuarzo doradas se controlaron
adicionalmente por espectrometrÃa IR.
El comportamiento resonante del QCR antes y después del recubrimiento de su superficie se midió con un analizador
de red. En combinación con una interfaz gráfica los datos se pudieron fácilmente grabar y observar.Technologies for thin film deposition have been used to improve the functionalization of quartz crystal resonators
(QCR); such technologies, for example, are spin coating and Langmuir-Blodgett (LB) film preparation. These experiments
are required because the film uniformity and homogeneity over the quartz crystal resonator are fundamental for
its applications as chemical and biological sensors.
Film deposition of polystyrene (PS) particles, as well as polyvinyl chloride (PVC), was performed in solvents
such as cyclohexanone, tetrahydrofuran (THF), dimethylformamide and chloroform at different concentrations using
the spin coating procedure on wafer targets. The film quality was determined by optical microscopy, ellipsometry, and
profilometry.
Additionally, films on wafers or QCR with gold surface have been prepared by spreading the mentioned substances
on an aqueous subphase and transferring it by dipping from the subphase surface onto the target.
For LB film preparation arachidic acid and PS particles have been used. Prepared mono- or multilayered films of
these substances on wafer or gold quartzes have been controlled additionally by IR-spectrometry.
The resonant behavior of QCR before and after surface coating has been measured with a network analyzer. In
combination with a graphical user interface the data could be easily recorded and visualized
Formal controller synthesis for wastewater systems with signal temporal logic constraints: the Barcelona case study
© . This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/We present an approach for formal controller synthesis of the Barcelona wastewater system. The goal of the controller is to minimize overflow in the system and to reduce environmental contamination (pollution). Due to the influence of sudden and unpredictable weather changes within the Mediterranean climate, we propose robust model predictive control strategy. This approach synthesizes control inputs (i.e., flows through network actuators) that make the system robust to uncertainties in the weather forecast; control inputs are updated in an online fashion to incorporate the newly available measurements from the system and the disturbances. We employ signal temporal logic as a formal mechanism to express the desired behavior of the system. The quantitative semantics of the logic is then used to encode the desired behavior in both the set of constraints and the objective function of the optimization problem. We propose a solution approach for the obtained worst-case optimization, which is based on transforming the nonlinear dynamics of the system into a mixed logical dynamical model. Then, we employ Monte Carlo sampling and dual reformulation to get a mixed integer linear or quadratic programming problem. The proposed approach is applied to a catchment of the Barcelona wastewater system to illustrate its effectiveness.Peer ReviewedPostprint (author's final draft
A gain-scheduled LPV control for oxygen stoichiometry regulation in PEM fuel cell systems
The article addresses the LPV control of a Polymer Electrolyte Membrane Fuel Cell (PEMFC). In order to optimize efficiency, PEMFCs require reliable control systems ensuring stability and performance, as well as robustness to model uncertainties
and external perturbations. On the other hand, PEMFCs present a highly nonlinear behavior that demands nonlinear and/or adaptive control strategies to achieve high performance in the entire operating range. Here, a linear parameter varying (LPV) gain scheduled control is proposed. The control is based on a piecewise affine LPV representation of the PEMFC, a model that can be available in practice. In order to deal with the saturation of the control action, an LPV anti-windup compensation is also proposed. The complete control strategy is applied to several experimental practical situations in a laboratory fuel cell system to evaluate its performance and the reliability of the proposed algorithms.The research of F.D. Bianchi was supported by the European Regional Development Funds (ERDF, FEDER Programa Competitivitat de Catalunya 2007-2013). The research of C. Kunusch has been supported by the Seventh Framework Programme of the European Community through the Marie Curie actions (GA: PCIG09-GA-2011-293876) and project Puma-Mind (GA: FCH-JU-2011-1-303419), as well as by the CICYT project DPI2011-25649 (MICINN-Spain). The research of C. Ocampo-Martinez has been supported by the project MACPERCON (Ref. 201250E027) of the CSIC. The research of R.S. Sánchez Peña has been supported by CONICET and
grant PICT2008-290 from the PRH Program of the Ministry of Science, Technology and Innovation of Argentina.Peer Reviewe
Solid-state cultures of Fusarium oxysporum transform aromatic components of olive-mill dry residue and reduce its phytotoxicity
The present study mainly investigated the ability of solid-state cultures of the non-pathogenic Fusarium oxysporum strain BAFC 738 to transform aromatic components to reduce the phytotoxicity in olive-mill dry residue (DOR), the waste from the two-phase manufacturing process. Lignin, hemicellulose, fats and water-soluble extractives contents of DOR colonized by the fungus for 20 weeks were reduced by 16%, 25%, 71% and 13%, respectively, while the cellulose content increased by 25%. In addition, the ethyl acetate-extractable phenolic fraction of the waste was reduced by 65%. However, mass-balance ultra-Wltration and size-exclusion chromatography experiments suggested that the apparent removal of that fraction, mainly including 2-(3,4-dihydroxyphenyl)ethyl alcohol and 2-(4-hydroxyphenyl) ethyl alcohol, was due to polymerization. Mn-peroxidase and Mn-independent peroxidase activities were found in F. oxysporum solid-state cultures, while laccase and aryl alcohol oxidase activities were not detected. Tests performed with seedlings of tomato (Lycopersicum esculentum L.), soybean (Glycine maximum Merr.), and alfalfa (Medicago sativa L.) grown on soils containing 6% (w/w) of bioconverted DOR (kg soil)¡1 showed that the waste’s phytotoxicity was removed by 20 weeks-old fungal cultures. By contrast, the same material exhibited a high residual toxicity towards lettuce (Lactuca sativa L.).L'articolo é disponibile sul sito dell'editore: http://www.sciencedirect.co
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