Miracle-dz/UniFAR-FTUs huggingface dataset:
Determinantes de la calidad docente: Programa de Asignación de Excelencia Pedagógica

Los docentes de establecimientos escolares constituyen desde siempre un factor clave del proceso educativo y de los resultados de aprendizaje de los estudiantes. En razon del rol constitucional que define al Estado como responsable de la provision de una educacion publica de calidad, es consustancial a su tarea atraer “buenos” profesores, retenerles y motivarles, via diversos mecanismos e incentivos, como tambien lo es, para el caso chileno, la generacion de mecanismos eficientes de evaluacion de su desempeno docente. En este marco se encuentra el Programa de Asignacion de Excelencia Pedagogica (AEP), el cual puede considerarse propiamente como un mecanismo de evaluacion e incentivo, pues intenta evaluar algunas dimensiones significativas de la calidad del docente, premiando los logros con un bono por encima de su salario regular. En razon de la importancia de la calidad docente en los establecimientos subvencionados por el Estado (municipales y particulares) para el desarrollo del pais y la sociedad, este trabajo tiene como objetivo determinar las caracteristicas de un docente que ha obtenido la acreditacion de calidad de la AEP, a traves de un modelo probit condicionado con datos de la Encuesta Longitudinal Docente (ELD), e igualmente estimar la probabilidad de participar. Se concluye que los factores que explican la probabilidad de ser acreditado son: experiencia, condicion socio-economica del hogar, nivel de estudios de la madre, estudios, pasantias y capacitaciones, calificacion de condiciones de salud, vocacion y calificacion del programa AEP, los cuales tienen efectos significativos pero reducidos
Breakthroughs in the Development of Semiconductor-Sensitized Solar Cells

Semiconductor sensitized solar cells have attracted growing interest in the past few years. Starting from quite low conversion efficiencies, these have grown very rapidly to values of around 4−5%. This Perspective analyzes the optimization of three aspects toward an increase in cell performance, (i) materials, including not only light-absorbing material but also electron and hole conductors and counter electrodes, (ii) control of recombination and band alignment by surface treatments, and (iii) development of absorbing nanocomposites with enhanced light-harvesting and -collecting properties. We argue that these key topics could promote major breakthroughs in the design and development of semiconductor-sensitized solar cells.
Essential Oil of Annona reticulata L. Leaves from Nigeria

Abstract Hydrodistilled oil obtained from the leaves of Annona reticulata L. grown in Nigeria was analyzed by capillary GC and GC/MS. Thirty-nine components were characterized. These consisted of 18 monoterpenes amounting to 29.0%, 20 sesquiterpenes totaling 52.9% and one aromatic esters making up 10.9%. The oil contained (E,E)-farnesyl acetate (19.0%), ar-turmerone (12.0%), benzyl benzoate (10.9%) and γ-terpinene (7.4%) as the major constituents.
Evaluation of Fuzzy Logic Subsets Effects on Maximum Power Point Tracking for Photovoltaic System

Photovoltaic system (PV) has nonlinear characteristics which are affected by changing the climate conditions and, in these characteristics, there is an operating point in which the maximum available power of PV is obtained. Fuzzy logic controller (FLC) is the artificial intelligent based maximum power point tracking (MPPT) method for obtaining the maximum power point (MPP). In this method, defining the logical rule and specific range of membership function has the significant effect on achieving the best and desirable results. This paper presents a detailed comparative survey of five general and main fuzzy logic subsets used for FLC technique in DC-DC boost converter. These rules and specific range of membership functions are implemented in the same system and the best fuzzy subset is obtained from the simulation results carried out in MATLAB. The proposed subset is able to track the maximum power point in minimum time with small oscillations and the highest system efficiency (95.7%). This investigation provides valuable results for all users who want to implement the reliable fuzzy logic subset for their works.
High Performance Cocktail Functional Monomer for Making Molecule Imprinting Polymer

In order to make a molecule imprinting polymer (MIP) with highly chiral selectivity against N-t-Boc - l -Trp, a new kind of “cocktail” functional monomer: acrylamide+2-vinylpyridine was investigated. The MIP showed impressive chiral selectivity ( α =3.23). With the increasing of water content in the mobile phase, ionic and hydrophobic interaction were found to be responsible for the chiral recognition process instead of the hydrogen bond. Tailing and peak asymmetry problems were overcome by using linear gradient elution. Physical properties such as thermal stability and pore structure for the MIP were also investigated.
Myoglobin-Clay Electrode for Nitric Oxide (NO) Detection in Solution

Sodium montmorillonite was prepared via a colloidal chemical approach and deposited onto glassy carbon electrodes (GCE). Myoglobin was immobilized on the clay membrane modified electrode by spontaneous adsorption. Characterization of the myoglobin/clay/glassy carbon electrode (Mb/clay/GCE) showed a quasi-reversible, electrochemical redox behavior of the adsorbed protein with a formal potential of −0.380±0.010 V (vs. Ag/AgCl). The heterogeneous electron transfer rate constant was found to be strongly influenced by the buffer concentration. The Mb/clay/GCE was stable for several days in solution. The interaction of the immobilized Mb with nitric oxide (NO) is characterized by coordination chemistry. The reaction was found to be reversible and could be applied for NO detection in the nanomolar concentration range by a voltammetric analysis. In addition a mixed protein electrode with co-immmobilized myoglobin (Mb) and cytochrome c (Cyt.c) was developed. By choice of the electrode potential both proteins can be addressed independently.
Low‐Temperature Studies. IV. The Phase Transitions of Ammonium Sulfate and Ammonium‐d4 Sulfate; the Nature of Hydrogen Bonding and the Reorientation of the NX4+ Ions

The temperature dependence of the infrared spectra of (NH4)2SO4 and (ND4)2SO4 between 17 and 298°K has been accurately determined. An analysis of the spectra of the high‐temperature and ferroelectric phases of (NH4)2SO4 supports the evidence of the neutron‐diffraction data of Schlemper and Hamilton that there is an increase in hydrogen bonding below 223°K. From the temperature variation of the peak heights of certain bands it is shown that graphs of this type can be used to determine the presence of any phase transitions accurately. Inflection points of these curves of (NH4)2SO4 at ∼ 160°K are correlated with the NMR linewidth transition at 163°K; it is the first time that such a correlation has been established. The temperature dependence of ND4+ stretching bands indicates the possible existence of three phases in (ND4)2SO4 (transition temperatures 225°K and ∼ 223°K). The torsional mode of the NH4+ ions has been identified; there is no evidence that the ion rotates “freely” at any temperature.
Dynamics of Excited Solvated Electrons in Aqueous Solution Monitored with Femtosecond-Time and Polarization Resolution

Transient pump−probe spectroscopy of equilibrated solvated electrons is carried out in aqueous NaCl solution (5.9 M) in the visible and near-infrared using pulses of 100−170 fs duration and polarization resolution. Excitation is performed by a pump pulse at 620 nm in the blue wing of the electronic absorption band. Transient bleaching occurs in a broad interval around the maximum of the e- absorption at 705 nm, accompanied by induced absorption at longer wavelengths. No hole-burning features are observed within our experimental time resolution suggesting a time constant τ1 < 80 fs for rapid solvent relaxation and/or population redistribution among the excited electronic states. The relaxation dynamics involves a first intermediate, a frequency-shifted excited-state p‘ with lifetime τ2 = 190 ± 40 fs. A further time constant τ3 = 1.2 ± 0.4 ps accounts for the recovery of the ground state. The latter process involves a second intermediate that is assigned as a modified ground-state s‘‘. Evidence for stimulat.
Enhanced stability of the second order optical properties of high-Tg fluorinated electro-optic copolymer

In this work the authors investigated the second order nonlinear optical properties of a group of Disperse Red 1 based electro-optic fluorinated copolymers, synthesized with two fluorinated monomers: the α-fluoroacrylate monomer bearing an adamantane side group and the α-fluoroacrylate monomer bearing the Disperse Red 1 chromophore. By means of nonlinear ellipsometry at λ=1550nm, the poling induced electro-optic tensor main component r33 was determined. The polymer’s thermostability was investigated by means of the temperature scanning and isothermal relaxation techniques, leading to the determination of the depolarization temperature Tdep=136°C, corresponding to an activation energy for the relaxation of the orientational distribution of the active chromophores EA=105kcal∕mol. The increased thermostability of the copolymer, given by the adamantane side group, is then compared with that of other two groups of fluorinated copolymers.
Interpretation of deuteron magnetic resonance spectroscopic studies of the hydration of macromolecules

Methods are given for the treatment of deuteron magnetic resonance data from macromolecular systems binding 2H2O, using results from lecithin dispersions to provide examples. Doublet splittings in such spectra measure the degree of anisotropy of water motion. By studying these splittings as a function of water content of the sample, the water content and characteristic splitting of each hydration “shell” may be found. Lecithin dispersions contain up to four kinds of water: bulk, trapped, loosely bound to the lipid, and tightly bound.Characteristic splittings in such systems are considerably less than those of ice and crystalline hydrates. Narrowing mechanisms are discussed, including water diffusion, motion of water-binding groups, and tumbling of water molecules in potential energy wells defined by the binding groups. The relative importance of each is found from the correlation times of each motion, using relaxation time measurements. In some cases the water spectrum gives information about motion of the binding group (e.g. “loosely bound” water for lecithin), while in others the splitting is related to the binding energy (> 0.3 kcal mol–1 for the water most tightly bound to lecithin). Relaxation data yield details of the orientation and anisotropic motions of this water.
Physicochemical and Advanced Oxidation Processes – A Comparison of Elimination Results of Antibiotic Compounds Following an MBR Treatment

The occurrence of pharmaceuticals in the environment has become a subject of concern in recent years. A vast number of these compounds have been detected in sewage treatment plants (STP) effluents, surface waters and, less frequently, in ground and drinking water all over the world. Adverse effects caused by pharmaceuticals include aquatic toxicity, resistance development in pathogenic bacteria, genotoxicity and endocrine disruption. Nowadays, it is widely accepted that the main source of pharmaceutical pollution in the aquatic environment are STPs effluents. Therefore, the discharge of pharmaceutical residues with the effluents of STPs should be minimized as far as possible. Degradation of persistent organic pollutants such as pharmaceuticals in water and wastewater can be achieved using advanced treatment technologies such as membrane bioreactors (MBRs) in combination with advanced oxidation processes (AOPS). This paper evaluates the treatment of three antibiotics of large consumption rates worldwide (roxithromycin, sulfamethoxazole and trimethoprim) by MBR followed by different AOP-steps. The identification and quantification of the precursor compounds and degradation products observable during the different treatment steps applied were performed with liquid chromatography coupled with high resolution mass spectrometry (LC-MS)
Influence of Coal as an Energy Source on Environmental Pollution

Abstract This article considers the influence of coal energy on environmental pollution. Coal is undoubtedly part of the greenhouse problem. The main emissions from coal combustion are sulfur dioxide (SO2), nitrogen oxides (NOx), particulates, carbon dioxide (CO2), and mercury (Hg). Since 1980, despite a 36% increase in electricity generation and more than a 50% increase in coal use, electric utility SO2 and NOx emissions have declined significantly. Globally, the largest source of anthropogenic greenhouse gas (GHG) emissions is CO2 from the combustion of fossil fuels—around 75% of total GHG emissions covered under the Kyoto Protocol. At the present time, coal is responsible for 30–40% of world CO2 emission from fossil fuels.
Electron-Stimulated Desorption of H + , H 2 + , OH + , and H + (H 2 O) n from Water-Covered Zirconia Surfaces

Electron beam induced production and desorption of H+, H2+, OH+, and H+(H2O)n has been studied from water-covered zirconia surfaces. The proton yield is strongly dependent upon the form of water present with large yields mainly from multilayers or clusters. The high proton kinetic energy distributions and the linear yield vs dose are indicative of proton formation and desorption by 2-hole and 2-hole, 1-electron final states. These localized states are produced either directly or via Auger decay pathways, and desorption occurs from the vacuum surface interface as a result of a Coulomb explosion. The proton yield increases from 80 to 150 K and then drops dramatically as the temperature exceeds 150 K. The increased yield is associated with structural and physical changes in the adsorbed water and longer excited-state lifetimes. The decreased yield is correlated with water desorption. Above 180 K, a small proton signal is observable which we associate with electron-stimulated dissociation of hydroxyl groups p.
Decay of dissolved substances by second-order reaction problem description and batch-reactor solutions

Abstract The mass transport (advection‐dispersion) equations allowing coupled second‐order reaction (i.e. ω1C1 + ω2C2 k12? Re) between two constituents are derived and result in a set of coupled nonlinear partial differential equations. Neglecting the spatial dependence simplifies the equations and produces coupled nonlinear ordinary differential equations for which several analytical solutions are provided. The solutions may be used to illustrate the effect of the second‐order reaction mechanism as well as providing a means for evaluating the reaction constant k12.
Improved Performance and Stability of Inverted Organic Solar Cells with Sol–Gel Processed, Amorphous Mixed Metal Oxide Electron Extraction Layers Comprising Alkaline Earth Metals

Stability of organic photovoltaic devices (OPVs) is a limiting factor for their commercialization and still remains a major challenge whilst power conversion efficiencies are now approaching minimum requirements. The inverted organic solar cell (iOSC) architecture shows promising potential for improving significantly the cell's working lifetime. However, when solution processed ZnO is used as electron extraction layer, an undesirable light‐soaking step is commonly required before the device reaches a non‐permanent maximum performance. This work investigates the use of Sr and Ba doped ZnO films, ZnSrO and ZnBaO, formed by sol‐gel deposition using molecular alkoxide precursor solutions, as electron extraction layers in a model iOSCs with poly [3‐hexylthiophene] (P3HT): [6, 6]‐phenyl C60 butyl acid methyl ester (PCBM) as the active layer. We show that using these ternary oxides the light‐soaking step can be circumvented by preventing a dipole forming between the oxide and the active organic layer as supported by electroabsorption spectroscopy measurements of the device built‐in field. It is suggested that Sr or Ba doping results in suppression/reduction of the oxygen adsorption at mobile oxygen vacancy sites on the metal oxide surface. Like in thin film transistor (TFT) applications, where materials like InGaZnO are rapidly becoming an important technology, the use of amorphous, mixed metal oxides allows improving the performance and stability of interfacial charge extraction layers for organic solar cells.
Bicontinuous, Thermoresponsive, L3‐Phase Silica Nanocomposites and Their Smart Drug‐Delivery Applications

The discovery that ordered nanoporous materials can be produced using a surfactant-templated approach has opened up a new era in the synthesis of ordered nanoscale materials. Many investigations have explored the preparation of nanoporous materials with novel chemical composition, the fundamental nature of the reaction processes and potential applications, such as catalysis and separation technology, which is expected to open up further application possibilities. Interest in the structure of the pore network is necessarily concomitant with the formation of different structures, including hexagonal, cubic, and lamellar structures. The liquid-crystal templating approach to these structures is based on a micellar or tubular structure. After templating, the inorganic precursor condenses to form a rigid cast of the underlying liquid crystal, and the organic phase can be removed to leave an inorganic solid composed of a periodic nanoporous structure with uniform diameter and distribution. Although the feasibility of choosing the pore size offers a wide range of possibilities for hosting different molecules, reports on the drug-delivery behavior of ordered nanoporous materials are not abundant and usually involve structural modification.
Temperature dependence of magnetic properties in Ni‐Mn‐Ga shape memory alloys

Due to exhibiting giant field-induce strain, the Ni2MnGa shape memory alloys are great interest for both scientific researches and industry applications. The non-stoichiometric Ni50Mn25+xGa25–x alloys with x varied from 1.5, 2.5 to 4 have been fabricated by arc-melting. Martensitic transformation temperature for structure transformation from tetragonal to cubic (TM) was observed from the magnetization, electrical resistivity and X-ray diffraction studies as functions of temperature below 400 K. We found that TM increases roughly from 280 K to 310K with increasing x from 1.5 to 4. However, the Curie transition (TC) is roughly at 380 K for all the samples, it is insensitive to the variation of Mn/Ga ratio. The electrical resistivity data exhibit a deep near TM and a slope change near TC. We have experimentally demonstrated that the shape memory effect can be occurred at room temperature with a proper concentration variation of Mn and Ga. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Calculated carbon-13 NMR relaxation parameters for a restricted internal diffusion model. Application to methionine relaxation in dihydrofolate reductase

/sup 13/C NMR relaxation parameters, T/sub 1/, T/sub 2/, and NOE, have been calculated based on a model assuming internal rotational diffusion subject to boundary conditions limiting the range of motion. Numerical results are presented as a function of diffusion coefficients D/sub 0/ and D/sub i/ and angle . beta. defined as in the free internal rotation calculation, as well as 2theta, the allowed range of motion. Relaxation times vary from values expected in the absence of internal motion to values slightly below those calculated using the free internal rotation model as the range is increased from 0 to 360/sup 0/. The discrepancy in the latter comparison arises from the boundary condition preventing diffusion from 180/sup +/ to 180/sup -/. Changes in T/sub 2/ are typically monotonic or nearly monotonic as a function of theta; however, changes in T/sub 1/ and NOE values are markedly nonmonotonic for D/sub 0/ approx. 180/sup 0/. Restriction of the motion allows a significantly better fit of data. 5 figures, 1 table. « less
Poly(phenylene) block copolymers bearing tri-sulfonated aromatic pendant groups for polymer electrolyte fuel cell applications

Novel poly(tri-sulfonated phenylene)-block-poly(arylene ether sulfone) copolymers (PTSP-b-PAESs) were synthesized by Ni(0)-catalyzed copolymerization of 2,5-dichloro-3′-sulfo-4′-((2,4-disulfo)phenoxy)-benzophenone and chlorobenzophenone-endcapped oligo(arylene ether sulfone). Their physical properties, morphology and polymer electrolyte fuel cell (PEFC) performance were investigated compared to those of poly(mono-sulfonated phenylene)-block-poly(arylene ether sulfone) and the corresponding random copolymers. They had a low ion exchange capacity (IEC) of 1.1–1.2 meq. g−1 and showed very low water uptake and in-plane dimensional change in water. They exhibited a more well-defined microphase-separated structure composed of hydrophilic and hydrophobic domains, where the hydrophilic domains were well-connected to each other to form the channels for proton conduction, than the mono-sulfonated one. This led to the relatively high proton conductivity under low relative humidities. The corresponding random copolymers exhibited a homogeneous morphology and much lower proton conductivity in spite of a high IEC of 2.0–2.1 meq. g−1. Even under the low humidification of 30% RH at 90 °C and 0.2 MPa, they exhibited high PEFC performance and durability; for example, a cell voltage of 0.69 V at a load current density of 0.5 A cm−2 and a maximum output of 0.73 W cm−2, which was comparable to that of the mono-sulfonated one with a much higher IEC of 1.8 meq. g−1 and much higher than those of the corresponding random copolymers. PTSP-b-PAESs have high potential as polymer electrolyte membranes for fuel cell applications.
Synthesis, Antibacterial and Antifungal Properties of Cyclohexane Tosyloxyimine Derivative

Due to increasing antimicrobial resistance, functionally substituted cyclohexane derivatives are being explored as potential antimicrobial agents. Reaction of diethyl 4 - hydroxy - 6 - (hyd - roxyimino) - 4 - methyl - 2 - phenylcyclohexane - 1,3 - dicarboxylate with 4 - toluene sulfonyl chloride in boiling acetone in the presence of equimolar triethylamine resulted in formation of diethyl - 4 - hydroxy - 4 - methyl - 2 - phenyl - 6 - ((tosyloxy)imino) cyclohexane - 1,3 - dicarboxylate. The structure of novel compound was characterized by 1 H and 13 C NMR spectra and elemental analysis was performed. Agar well diffusion assay was used to screen novel compound against Gram - positive bacteria, Gram - negative bacteria and fungi. Test compound showed better antimicrobial properties against Gram - negative bac teria as compared to Gram - positive bacteria and fungi. Acinetobacter baumannii BDU - 32 was found to be most sensitive bacteria while Candida pseudotropicalis BDU MA88 was found to be most sensitive yeast.
The Drinking Water Taste and Odor Wheel for the Millennium: Beyond Geosmin and 2-Methylisoborneol

The “Taste and Odor Wheel” developed over the last 15 years has been updated to include new compounds identified in the eight classes of odorants, four tastes, and one mouth feel/nose feel category. Over the last 10 years, other types of odors have been identified, in addition to chlorinous and ozonous odors of disinfectants, the earthy compound geosmin, and the musty compound 2-methylisoborneol (2-MIB). Sophisticated instrumental analysis, e.g., gas chromatography/mass spectrometry (GC/MS), and sensory analysis, e.g., flavor-profile analysis (FPA), have been successfully combined with sensory GC to identify various odorants.