1,527 research outputs found

    Metal Halide Perovskites for Solar-to-Chemical Fuel Conversion

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    This review article presents and discusses the recent progress made in the stabilization, protection, improvement, and design of halide perovskite‐based photocatalysts, photoelectrodes, and devices for solar‐to‐chemical fuel conversion. With the target of water splitting, hydrogen iodide splitting, and CO2 reduction reactions, the strategies established for halide perovskites used in photocatalytic particle‐suspension systems, photoelectrode thin‐film systems, and photovoltaic‐(photo)electrocatalysis tandem systems are organized and introduced. Moreover, recent achievements in discovering new and stable halide perovskite materials, developing protective and functional shells and layers, designing proper reaction solution systems, and tandem device configurations are emphasized and discussed. Perspectives on the future design of halide perovskite materials and devices for solar‐to‐chemical fuel conversion are provided. This review may serve as a guide for researchers interested in utilizing halide perovskite materials for solar‐to‐chemical fuel conversion

    Report of the Executive Council's Working Group on the Establishment of a CGIAR Science Council

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    This paper was prepared for the Executive Council by the Working Goup on the Establishment of a CGIAR Science Council. It is a detailed proposal on how the CGIAR Technical Advisory Committee could be transformed into a Science Council. The report calls for the creation of a small independent Science Council that would enjoy a wider mandate in scope than TAC's current mandate. The report contains eleven recommendations.This document was discussed at the business meeting during AGM02

    Understanding social interpersonal interaction via synchronization templates of facial events

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    Automatic facial expression analysis in inter-personal communication is challenging. Not only because conversation partners' facial expressions mutually influence each other, but also because no correct interpretation of facial expressions is possible without taking social context into account. In this paper, we propose a probabilistic framework to model interactional synchronization between conversation partners based on their facial expressions. Interactional synchronization manifests temporal dynamics of conversation partners' mutual influence. In particular, the model allows us to discover a set of common and unique facial synchronization templates directly from natural interpersonal interaction without recourse to any predefined labeling schemes. The facial synchronization templates represent periodical facial event coordinations shared by multiple conversation pairs in a specific social context. We test our model on two different dyadic conversations of negotiation and job-interview. Based on the discovered facial event coordination, we are able to predict their conversation outcomes with higher accuracy than HMMs and GMMs

    A transfer learning-based feature reduction method to improve classification accuracy

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    The need for efficient data use grows in machine learning algorithm for dataset with larger feature sets. Feature selection is the process of selecting minimum set of features that fully represent the learning problem. Transfer learning can motivate in scenario where we train model with the common problem and use it to identify important features needed to build model for target problem. In this thesis, we propose transfer learning algorithm combined with or without suggested features from experts, to learn from the source dataset and recognize important feature sets needed to train models in target dataset. Also, we compared this algorithm with classical machine learning algorithm with or without using the suggested features recommended by the experts. In series of experiment, it shows that our method is adequate to find the minimum feature sets which also outperformed then using only the suggested features by the experts. Furthermore, it also shows that the subsequent reduce in number of features in transfer learning method have better or almost same performance then using all the features of the dataset. We performed our experiments using heart disease, readmission dataset and BMI dataset

    Toward an African-American critical pedagogy for liberation

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    This dissertation, as a qualitative study, focuses on critical pedagogy and dialogic teaching as seen through the lenses of dominant reconstructionist theorists. Perceived as essential for African-American education, critical pedagogy and dialogic teaching serve as analytical structures for defining education deficiencies and for proposing major pedagogical transformations, so that schools, colleges, and universities can more effectively fulfill the needs of students and American minorities. Such a mission entails an ideological examination of African-American insights on how American schools have failed this minority through the propagation of White hegemony and an investigation of pedagogical impediments facing African-Americans in traditional American schools. Likewise, it centers around analyses of critical educational theories, followed by the creation of an African-American critical pedagogy to enlighten and consider all people and their need for freedom, integrity, and equality. Because an African-American pedagogy seeks to liberate African- Americans from political and socio-economic oppression, it means taking risks to create a more just and equitable society and demands acknowledgement of education as a political, social, cultural, and moral enterprise, laying a pathway for chang

    Hypervalent Iodonium Alkynyl Triflate Generated Phenylcyanocarbene and Its Reactivity with Aromatic Systems

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    Phenylcyanocarbene was generated by the reaction of azide with a hypervalent iodonium alkynyl triflate and reacted in situ with 21 different carbocyclic and heterocyclic aromatic compounds. These reactions led to more complex products that frequently underwent subsequent rearrangements. The reactivity was further explored in a mechanistic study to ascertain the chemoselectivity and stereospecificity

    Palladium-Catalyzed Chemoselective Protodecarboxylation of Polyenoic Acids

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    Conditions for the first palladium-catalyzed chemoselective protodecarboxylation of polyenoic acids to give the desired polyenes in good yields are presented. The reactions proceed under mild conditions using either a Pd(0) or Pd(II) catalyst and tolerate a variety of aryl and aliphatic substitutions. Unique aspects of the reaction include the requirement of phosphines, water, and a polyene adjacent to the carboxylic acid

    Decarboxylative and dehydrative coupling of dienoic acids and pentadienyl alcohols to form 1,3,6,8-tetraenes

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    Dienoic acids and pentadienyl alcohols are coupled in a decarboxylative and dehydrative manner at ambient temperature using Pd(0) catalysis to generate 1,3,6,8-tetraenes. Contrary to related decarboxylative coupling reactions, an anion-stabilizing group is not required adjacent to the carboxyl group. Of mechanistic importance, it appears that both the diene of the acid and the diene of the alcohol are required for this reaction. To further understand this reaction, substitutions at every unique position of both coupling partners was examined and two potential mechanisms are presented

    Manufacturing employment adjustment: assessing the effect of trade exposure in Canada

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    Using data from the 10 Canadian provinces, we assess the effect of manufacturing sector exposure to trade on employment adjustment based on static, partial and general models of adjustment. From the results across these adjustment models, real exports and real imports have positive and negative effects on manufacturing employment, respectively. This is quite consistent with the popular assertion that exports create jobs and imports displace them. However, based on the net effects analysis, there was not enough evidence to predict that trade exposure is responsible for the declining trend in manufacturing sector employment over the last two decades. When we look at trade intensity effect by country of origin, employment adjustment has different impacts, with import intensities from the U.S. and China showing positive effect, while the effect of E.U. import intensity is negative

    Adult and paediatric mortality patterns in a referral hospital in Liberia 1 year after the end of the war

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    The aim of this study was to describe and analyse hospital mortality patterns after the Liberian war. Data were collected retrospectively from January to July 2005 in a referral hospital in Monrovia, Liberia. The overall fatality rate was 17.2% (438/2543) of medical admissions. One-third of deaths occurred in the first 24h. The adult fatality rate was 23.3% (241/1034). Non-infectious diseases accounted for 56% of the adult deaths. The main causes of death were meningitis (16%), stroke (14%) and heart failure (10%). Associated fatality rates were 48%, 54% and 31% respectively. The paediatric fatality rate was 13.1% (197/1509). Infectious diseases caused 66% of paediatric deaths. In infants <1 month old, the fatality rate was 18% and main causes of death were neonatal sepsis (47%), respiratory distress (24%) and prematurity (18%). The main causes of death in infants > or =1 month old were respiratory infections (27%), malaria (23%) and severe malnutrition (16%). Associated fatality rates were 12%, 10% and 19%. Fatality rates were similar to those found in other sub-Saharan countries without a previous conflict. Early deaths could decrease through recognition and early referral of severe cases from health centres to the hospital and through assessment and priority treatment of these patients at arrival
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