bluuebunny/crossref_metadata_2025 huggingface dataset:
Counter-Ion Effect on the Thermodynamics of Cr(III) Exchange by Macroporous Amberlyst-15
Authors: Shah Khizar Hussain , Mustafa Syed , Waseem Muhammad , Hamayun Muhammad , Syed Murtaza , Shah Faheem , Khan Abdur Rahman , Rehman Wajid
Published: May 2017

In the present study, we have investigated the counter-ion effect on the thermodynamics of Cr(III) sorption by macroporous resin Amberlyst-15. The exchange reaction was studied as a function of concentration of Cr(III) and nature of counter-ions at different temperatures. It was observed that nature of counter-ions have a profound effect on the exchange of Cr(III) ions. The selectivity of Amberlyst-15 towards metal ion sorption follows the order univalent>divalent> trivalent forms. This trend can be associated to the electrostatic interaction of ions with the functional sites of the resin. The equilibrium pH values (pHeq) were observed to decrease with Cr3+/H+ exchange whereas an increase in pHeq was detected during the exchange of Cr3+/Li+, Cr3+/Na+, Cr3+/Ca2+ and Cr3+/Al3+. Different adsorption models such as Dubinin–Radushkevich (D–R) and Langmuir were employed to analyze the sorption data. The maximum exchange capacities (X

m
) and binding energy constants (K

b
) values were determined by using the Langmuir model. The values of both ΔHo and ΔSo were found positive inferring that the exchange process is endothermic accompanied by the dehydration of Cr(III) ions. The thermodynamic parameters revealed that the mechanism of Cr(III) sorption for all the counter ions is entropy driven ion exchange.
Spectroscopic Properties of Yb3+-Doped Silicate Glasses
Authors: Linganna Kadathala , Ju Seongmin , Kim Bokhyeon , Han Won-Taek , Venkatramu Vemula , Jayasankar Chalicheemalapalli Kulala
Published: May 2017

Yb3+-doped silicate glasses (SiO2–Nb2O5–K2O–ZnF2) were prepared by a conventional melt quenching technique and their spectroscopic properties were investigated. The emission cross-section was found to be 0.53×10−20 cm2 at 1006 nm from the reciprocity method described by McCumber from the measured absorption spectrum of 1.0 mol% Yb2O3-doped glass. The lifetime (τ
exp) and figure of merit (σem
×τ
exp) for the 2F5/2→2F7/2 transition of 1.0 mol% Yb2O3 -doped silicate glass, were evaluated to be 0.50 ms and 0.26 cm2 ms, respectively. The other spectroscopic parameters, β
min, I
sat and I
min were found to be 0.17, 29.00 kW/cm2 and 4.90 kW/cm2, respectively. The results indicate that the present Yb3+-doped silicate glasses could be useful as laser gain media at 1006 nm.
Real-life GH dosing patterns in children with GHD, TS or born SGA: a report from the NordiNet® International Outcome Study
Authors: Blankenstein Oliver , Snajderova Marta , Blair Jo , Pournara Effie , Pedersen Birgitte Tønnes , Petit Isabelle Oliver
Published: May 2017

Objective

To describe real-life dosing patterns in children with growth hormone deficiency (GHD), born small for gestational age (SGA) or with Turner syndrome (TS) receiving growth hormone (GH) and enrolled in the NordiNet International Outcome Study (IOS; Nbib960128) between 2006 and 2016.

Design

This non-interventional, multicentre study included paediatric patients diagnosed with GHD (isolated (IGHD) or multiple pituitary hormone deficiency (MPHD)), born SGA or with TS and treated according to everyday clinical practice from the Czech Republic (IGHD/MPHD/SGA/TS: n = 425/61/316/119), France (n = 1404/188/970/206), Germany (n = 2603/351/1387/411) and the UK (n = 259/60/87/35).

Methods

GH dosing was compared descriptively across countries and indications. Proportions of patients by GH dose group (low/medium/high) or GH dose change (decrease/increase/no change) during years 1 and 2 were also evaluated across countries and indications.

Results

In the Czech Republic, GH dosing was generally within recommended levels. In France, average GH doses were higher for patients with IGHD, MPHD and SGA than in other countries. GH doses in TS tended to be at the lower end of the recommended label range, especially in Germany and the UK; the majority of patients were in the low-dose group. A significant inverse association between baseline height standard deviation score and GH dose was shown (P < 0.05); shorter patients received higher doses. Changes in GH dose, particularly increases, were more common in the second (40%) than in the first year (25%).

Conclusions

GH dosing varies considerably across countries and indications. In particular, almost half of girls with TS received GH doses below practice guidelines and label recommendations.
A Novel Histone Crosstalk Pathway Important for Regulation of UV-Induced DNA Damage Repair in Saccharomyces cerevisiae
Authors: Boudoures Anna L , Pfeil Jacob J , Steenkiste Elizabeth M , Hoffman Rachel A , Bailey Elizabeth A , Wilkes Sara E , Higdon Sarah K , Thompson Jeffrey S
Published: May 2017

Histone post-translational modifications play vital roles in a variety of nuclear processes, including DNA repair. It has been previously shown that histone H3K79 methylation is important for the cellular response to DNA damage caused by ultraviolet (UV) radiation, with evidence that specific methylation states play distinct roles in UV repair. Here, we report that H3K79 methylation is reduced in response to UV exposure in Saccharomyces cerevisiae. This reduction is specific to the dimethylated state, as trimethylation levels are minimally altered by UV exposure. Inhibition of this reduction has a deleterious effect on UV-induced sister chromatid exchange, suggesting that H3K79 dimethylation levels play a regulatory role in UV repair. Further evidence implicates an additional role for H3K79 dimethylation levels in error-free translesion synthesis, but not in UV-induced G1/S checkpoint activation or double-stranded break repair. Additionally, we find that H3K79 dimethylation levels are influenced by acetylatable lysines on the histone H4 N-terminal tail, which are hyperacetylated in response to UV exposure. Preclusion of H4 acetylation prevents UV-induced reduction of H3K79 dimethylation, and similarly has a negative effect on UV-induced sister chromatid exchange. These results point to the existence of a novel histone crosstalk pathway that is important for the regulation of UV-induced DNA damage repair.
Orthogonal Estimates of Variances for Additive, Dominance, and Epistatic Effects in Populations
Authors: Vitezica Zulma G , Legarra Andrés , Toro Miguel A , Varona Luis
Published: May 2017

Genomic prediction methods based on multiple markers have potential to include nonadditive effects in prediction and analysis of complex traits. However, most developments assume a Hardy–Weinberg equilibrium (HWE). Statistical approaches for genomic selection that account for dominance and epistasis in a general context, without assuming HWE (e.g., crosses or homozygous lines), are therefore needed. Our method expands the natural and orthogonal interactions (NOIA) approach, which builds incidence matrices based on genotypic (not allelic) frequencies, to include genome-wide epistasis for an arbitrary number of interacting loci in a genomic evaluation context. This results in an orthogonal partition of the variances, which is not warranted otherwise. We also present the partition of variance as a function of genotypic values and frequencies following Cockerham’s orthogonal contrast approach. Then we prove for the first time that, even not in HWE, the multiple-loci NOIA method is equivalent to construct epistatic genomic relationship matrices for higher-order interactions using Hadamard products of additive and dominant genomic orthogonal relationships. A standardization based on the trace of the relationship matrices is, however, needed. We illustrate these results with two simulated F1 (not in HWE) populations, either in linkage equilibrium (LE), or in linkage disequilibrium (LD) and divergent selection, and pure biological dominant pairwise epistasis. In the LE case, correct and orthogonal estimates of variances were obtained using NOIA genomic relationships but not if relationships were constructed assuming HWE. For the LD simulation, differences were smaller, due to the smaller deviation of the F1 from HWE. Wrongly assuming HWE to build genomic relationships and estimate variance components yields biased estimates, inflates the total genetic variance, and the estimates are not empirically orthogonal. The NOIA method to build genomic relationships, coupled with the use of Hadamard products for epistatic terms, allows the obtaining of correct estimates in populations either in HWE or not in HWE, and extends to any order of epistatic interactions.
Valorizando los efectos de las emigraciones y las remesas: Una comunidad costarricense ante la (re)estructuración de jerarquías de género y clase
Authors: Rodríguez Leila
Published: May 2017

Este artículo se basa en una investigación descriptiva sobre la percepción que tienen los residentes de un pueblo rural en Costa Rica sobre el efecto de la emigración internacional en su comunidad. En particular, examina la economía moral –las valoraciones morales de miembros actuales de la comunidad ante los cambios socioeconómicos que las emigraciones conllevan. Basado en entrevistas cualitativas con no-migrantes y migrantes de retorno, los resultados demuestran que el patrón migratorio con mayor aceptación por parte de la comunidad es el temporal, de corto plazo, y que genere remesas que sean invertidas en actividades productivas en la comunidad. Se concluye que la economía moral desarrollada reproduce el guion idealizado de una comunidad rural igualitaria (re)producida por la familia tradicional.
Minería, resistencia y represión en Honduras: entre la ley y la impunidad
Authors: Middeldorp Nick
Published: May 2017

Esta artículo, basado en una investigación etnográfica de 6 meses entre mayo y noviembre del 2013, analiza la conflictividad social causada por la expansión de la frontera minera en Honduras: el movimiento antiminero logra movilizar a las comunidades rurales para declarar sus municipios libre de minería; mientras tanto, la industria minera puede circunvenir el derecho legal a la consulta a través de la criminalización de protesta y el uso de violencia. Este artículo plantea serias preocupaciones sobre esta tendencia e indica que los movimientos sociales son capaces de adaptarse y desarrollar resistencias exitosas en ambientes políticamente y jurídicamente complejos.
Estéticas en plural. La moda popular en Bogotá
Authors: Salazar Edward
Published: May 2017

Este artículo presenta los resultados y las reflexiones de la investigación sobre la moda, la estética y la indumentaria en los sectores populares en Bogotá durante el 2011 y el 2012, realizada por medio de técnicas cualitativas como el análisis de la imagen, la observación etnográfica y la entrevista. El propósito es analizar las distancias y acercamientos que existen entre la moda popular y la moda hegemónica para dar cuenta de la necesidad de hablar de las modas, pues existen diferentes visiones estéticas que un concepto singular no recoge. La moda popular toma, reinterpreta y problematiza la cultura material de la indumentaria producida por la moda hegemónica, a la vez que produce sus propios referentes que deben ser considerados como moda por cumplir con las premisas fundamentales del concepto, develando la preconcepción de clase que existe sobre este tema.
Épicas barriales: lo público-político vivo
Authors: Gravano Ariel
Published: May 2017

El objetivo del trabajo apunta a responder el interrogante por los sentidos políticos de las narrativas barriales que se definen como épicas, en contextos de luchas por el espacio urbano y por consumos colectivos. Se abarcan casos en una región metropolitana (ciudad de Buenos Aires) y una ciudad media (del centro de la provincia de Buenos Aires), en un lapso que va desde la década del sesenta del siglo XX hasta el presente. La base metodológica etnográfica del enfoque se proyecta en casos de construcción de identidades barriales y procesos de movilización y participación. A partir de la teoría de los movimientos sociales y de lo urbano estructural-significacional, se aborda la relación entre la concepción de lo público y la ciudadanía desde la crítica al clásico prisma idealista-burgués y a las asunciones del vecinalismo culturalista. El análisis interpretativo se posiciona en una dialéctica de lo público -desde el concepto de Carlos Marx y en debate con la clásica posición idealista- hacia lo que definimos como lo político vivo.
Theoretical Aspects of Doping of Photovoltaic Materials
Authors: Katayama-Yoshida H.
Published: May 2017

The low-resistive p- and n-type transparent conductors are necessary for the efficient photovoltaic (PV) solar cells. We review a new valence control method of co-doping with doping Ga- (or In-, or Alsubstitutional impurity, and Li-interstitial impurity) donor and N-acceptor at the same time for the fabrication of a low-resistive p-type ZnO based upon the ab initio calculation. We compare our materials design to fabricate a low resistive p -type ZnO with the recent successful co-doping experiments. The Delafossite structure of CuAlO2 has great potentiality far p-type transparent conducting oxide to apply the high efficient photovoltaic solar-cells combined with n-type transparent conducting oxides such as ITO (indium tin oxides), SnO2 or ZnO. We have calculated the electronic structure, impurity levels, and formation energy of Cu-vacancy, Al-vacancy, Be, Mg, Ca acceptors at the Al-site, and Be, Mg, Ca donors at the Cu-site. Calculated acceptor energy levels are as follows; Cu-vacancy (-300meV from the VBM [valence band maximum]), Al-vacancy (671 meV from the VBM), Be-acceptor (85 meV from the VBM), Mg-acceptor (200 meV from the VBM), and Ca-acceptor (960 meV from the VBM). We find that the Mg impurity at the Cu-site is more stable than the Al-site. Therefore, Mg impurity acts as donor at the Cu-site in the CuAlO2. This is the reason why Mg doping reduces the p-type conductivity in CuAlO2. We propose the following valence control method for the fabrication of p-type CuAlO2; we should dope the high concentration of Cu-vacancy in order to form the impurity band with reducing the Cu vapor pressure during the PLD or MBE crystal growth method, or we dope the Mg or Be acceptors at the Al-site with reducing the Al vapor pressure and increasing the Cu vapor pressure during the thermal non-equilibrium crystal growth method such as MBE or MOCVD. We compare our materials design with the available experimental data. Finally, we propose the co-doping by 2PS(Se)+InCu+VCu for the fabrication of p-type CuInS2 or CuInSe2 based upon ab initio electronic structure calculation.
The Dynamics of Cadmium Telluride Etching
Authors: Dobson K. D. , Paulson P. D. , McCandless B. E. , Birkmire R. W.
Published: May 2017

CdTe etching was investigated using variable angle spectroscopic ellipsometry and glancing angle x-ray diffraction. Treatment with HNO3:H3PO4 (NP) based etches was shown to form amorphous-Te surface films which spontaneously crystallize following etching. Br2/methanol (BM) etching forms very thin amorphous-Te films. NP-etched surfaces are stable in ambient air for ∼1 hr before beginning to oxidize, while BM etched films oxidize immediately following treatment. CdTe grain boundary etching by NP was minimized using more acidic etches. Device analysis suggests that a higher Te content produces more stable back contacts by attenuating Cu diffusion. Mechanistic details of NP etching are discussed.
14% CdS/CdTe Thin Film Cells with ZnO:Al TCO
Authors: Gupta Akhlesh , Compaan Alvin D.
Published: May 2017

An Al-doped ZnO front contact was successfully used for the first time for the fabrication of high efficiency CdS/CdTe thin-film solar cells. The ZnO:Al films were deposited on aluminosilicate glass by RF sputtering from a ZnO:Al2O3 target. The ZnO:Al film has ∼95% average transmission in the visible spectrum with ∼3 ohm/square sheet resistance. The CdS and CdTe thin films were also deposited by RF sputtering and devices were completed with a vapor CdCl2 treatment and evaporated Cu/Au back contacts. The highest processing temperature was 387°C, reached during the vapor CdCl2 treatment. The devices were tested at NREL with efficiency of 14.0% which is a record for an all-sputtered CdS/CdTe solar cell. The ZnO-based cell had JSC of 23.6 mA/cm2 compared to 20.7 mA/cm2 for our recent NREL-tested 12.6% cell on a commercial soda-lime-glass/SnO2:F substrate. Other parameters of the 14% ZnO based cell are: FF = 73.25% and VOC = 814 mV. The improved performance is almost entirely due to higher current because of better optical and electrical properties of ZnO:Al TCO. We report also on relative stability between devices on SnO2:F and ZnO:Al TCO, under one-sun light soak at VOC.
Low Temperature Deposition of Zinc Oxide Films
Authors: Lee H. W. , Wang Y. G. , Lau S. P. , Tay B. K.
Published: May 2017

A detailed study of zinc oxide (ZnO) films prepared by filtered cathodic vacuum arc (FCVA) technique was carried out. To deposit the films, a pure zinc target was used and O2 was fed into the chamber. The electrical properties of both undoped and Al-doped ZnO films were studied. For preparing the Al-doped films, a Zn-Al alloy target with 5 wt % Al was used. The resistivity, Hall mobility and carrier concentration of the samples were measured. The lowest resistivity that can be achieved with undoped ZnO films was 3.4×10-3 Ωcm, and that for Al-doped films was 8×10-4 Ωcm. The carrier concentration was found to increase with Al doping.
Preparation and Characterization of Cu-Ga-Se Films of Ordered Vacancy Compound
Authors: Nishiwaki S. , Siebentritt S. , Lux-Steiner M. Ch.
Published: May 2017

Cu-Ga-Se films with an orderd vacancy compound (OVC) structure were prepared at substrate temperature about 500 °C by thermal co-deposition. With a preparation under extremely Se excess condition, films of the OVC were synthesized within the compositional ratio of 0.73 ≤ [Ga]/([Cu]+[Ga]) ≤ 0.86 along Cu2Se-Ga2Se3 pseudo binary system. The growth on soda-lime glass substrates improves the crystallinity compared to that on alkali-free glass. An increase in the optical bandgaps of OVC films from 1.85 eV to 1.94 eV was observed with an increase in the Ga content of the films. The deposition of Cu and Se onto Ga2Se3 films resulted in a vertically inhomogeneous film: the bottom layer with the OVC structure and the top layer with the chalcopyrite structure. A solar cell using the CuGa5.0Se8.1 film within a ZnO/CdS/CuGa-Se/Mo/soda-lime glass substrate structure showed an open circuit voltage of 947 mV, an efficiency of 2.2 %, a short circuit current density of 4.5 mA/cm2, and a fill factor of 0.52 (Air Mass 1.5, 0.5 cm2, total area).
Evolution of Electronic Properties of Cu(In, Ga)Se2 (CIGS)-Based Solar Cells During a 3-stage Growth Process
Authors: AbuShama Jehad A. , Johnston S. , Ahrenkiel R. , Crandall R. , Young D. , Noufi R.
Published: May 2017

We investigated the electronic properties of ZnO/CdS/CIGS/Mo/SLG polycrystalline thin-film solar cells with compositions ranging from Cu-rich to In(Ga)-rich by deep-level transient spectroscopy (DLTS) and capacitance-voltage (C-V) measurements. This compositional change represents the evolution of the film during growth by the 3-stage process. Two sets (four samples each) of CIGS thin films were prepared with Ga/(In+Ga) ratios of ∼0.3 (low Ga) and ∼0.6 (high Ga). The Cu/(In+Ga) ratio ranges from 1.24 (Cu-rich) to 0.88 (In(Ga)-rich). The films were treated with NaCN to remove the Cu2-xSe phase where needed. Key results include: (1) For lowGa devices, DLTS data show that acceptor-like traps dominate in samples where CIGS grains do not go through the Cu-rich to In(Ga)-rich transition, whereas donor-like traps dominate in In(Ga)-rich samples. Therefore, we see a clear transformation of defects from acceptor-like to donor-like traps. The activation energies of these traps range from 0.12 to 0.63 eV. We also observed that NaCN treatment eliminates a deep minority trap in the In(Ga)-rich devices, (2) For high-Ga devices, only majority-carrier traps were detected. These traps again range from shallow to deep, (3) The carrier concentration around the junction and the density of traps decrease as the CIGS becomes more In(Ga)-rich.
Formation Energies of Point Defects in Copper Indium Diselenide Using ab initio Methods
Authors: Domain C. , Raulot J.M. , Laribi S. , Taunier S. , Guillemoles J.F.
Published: May 2017

The opto-electronic properties of CuInSe2 and related compounds depend on their defect chemistry in a way that is far from being understood and in which ab initio calculations could help by providing new insights as shown previously. Ab initio calculations of energy and electronic structure of various intrinsic (including defect pairs) and extrinsic (including potential dopants such as Zn) point defects have been performed in the chalcopyrite semiconductors CuInSe2, some of them being computed for the first time by advanced ab initio techniques. The method used is based on the density functional theory within the framework of pseudo-potentials and plane waves basis set. The results are discussed in view of the existing data, models and calculations.
Modification of Cu(In, Ga)Se2 Surface by Treatment in Cadmium Solutions
Authors: Nguyen Q. , Bilger G. , Rau U. , Schock H.W.
Published: May 2017

This article investigates chemical modifications of Cu(In, Ga)Se2 thin film by treatment in cadmium solutions with varying [NH3] concentration. Secondary ions mass spectroscopy and Xray photoelectron-spectroscopy analysis show that Cd-diffusion into the Cu(In, Ga)Se2 film is intimately tied to the reduction-oxidation of the Cu(In, Ga)Se2 surface, which is controlled by the [NH3] concentration. Reaction products, like Se and metal hydroxides of the redox process as wellas thediffusedCdinCu(In, Ga)Se2 film, result in degradation of solar cell performance.
Measurement of Built-in Electrical Potential in Cu(In, Ga)Se2 Solar Cells
Authors: Jiang C.-S. , Hasoon F.S. , Moutinho H.R. , Al-Thani H.A. , Romero M.J. , Al-Jassim M.M.
Published: May 2017

The built-in electrical potential on cross sections of Cu(In, Ga)Se2 (CIGS) solar cells was measured quantitatively and resolved spatially using scanning Kelvin probe microscopy. In the conditions of open and short circuits, no significant potential variation on the p-n junction was probed due to the surface Fermi-level pinning. With an external reverse-bias voltage applied to the device, we were able to probe the potential on the junction; the potential profiles demonstrate that the p-n junction is a buried homojunction, located 30-80 nm from the CIGS/CdS interface in the CIGS film. The potential measurement over the CdS and ZnO layers, which is consistent with the band diagram calculations, indicates that the CdS and ZnO layers are inactive for the collection of photoexcited carriers.
Nucleation of Cu(In, Ga)Se2 on Molybdenum Substrates
Authors: Schlenker T. , Orgassa K. , Schock H. W. , Werner J. H.
Published: May 2017

We investigate growth mechanisms of Cu(In, Ga)Se2 on Mo films on glass, as the typical back contact for Cu(In, Ga)Se2 solar cells. A thermal evaporation process deposits Cu(In, Ga)Se2of nominal 3 nm thickness at different rates R and substrate temperatures TSub. An ultrahigh resolution scanning electron microscope serves to investigate the nucleation behavior. The deposited Cu(In, Ga)Se2 forms three-dimensional isolated nuclei, known as Volmer-Weber growth mode. Deposition rate R and substrate temperature TSub control the areal density n of the Cu(In, Ga)Se2 nuclei. We observe a power law dependence between the island density n and the deposition rate R, and an exponential dependence of the island density n on substrate temperature TSub. The theory of homogeneous nucleation explains the Cu(In, Ga)Se2 cluster formation on polycrystalline Mo and the dependence of the island density on the growth conditions.
Photoconductive CdS: how does it Affect CdTe/CdS Solar Cell Performance?
Authors: Hegedus S. , Ryan D. , Dobson K. , McCandless B. , Desai D.
Published: May 2017

Photoconductive CdS (PC-CdS) in CdS/CdTe solar cells from five different sources is investigated using spectral sensitization of apparent quantum efficiency (AQE) and J-V analysis. Red bias light significantly enhances the blue AQE, commonly leading to AQE>1 below 550 nm, and blue bias light enhances the red AQE, but to a much smaller extent. These enhancements are more pronounced with increasing forward bias, after stress and in devices with intentionally Cu-doped CdS. This behavior is observed to some degree in all devices with CdS, but is absent in cells without CdS. These effects are consistent with blue light, either ac monochromatic or dc bias, increasing the CdS conductivity. This causes an increase in the field and depletion width in the CdTe to maintain balanced space charge, leading to increased collection of carriers from the CdTe. The CdS conductivity modulation can also change the AQE due to a change in equivalent circuit resistance. Analysis of J-V data measured with white, blue, red or no light indicates little dependence of series resistance or diode quality factor on the illumination spectrum. Thus, the PC-CdS resistance has little effect on the solar cell J-V performance, but does influence AQE.
How to deal with the unmotivated medical student in small group sessions?
Authors: Hensen Nienke M.J. , ten Cate Olle
Published: May 2017

This article was migrated. The article was marked as recommended. Introduction: To increase the motivation of students at small group seminar education sessions, teachers and institutions often revert to rewarding the prepared students and/or punishing those who did not prepare. How effective is that? We sought to find theoretical claims or disclaims for this policy from Self-Determination Theory, which is an important contemporary theory about motivation. SDT distinguishes intrinsic and extrinsic motivation and provides evidence for the use of rewards and punishments. Aim: The primary aim was to explore the effects of extrinsic rewards and negative incentives on the intrinsic motivation in the literature. A secondary goal was to provide practical tips for teachers to improve the motivation of medical students. Results: Verbal rewards can increase the intrinsic motivation. Unexpected tangible and task-non-contingent tangible rewards appear to have no detrimental effect on the intrinsic motivation. All other expected tangible rewards and negative incentives, like threats and deadlines, have been found to undermine the intrinsic motivation. Autonomous self-regulated learning (intrinsic motivation, identified regulation and/or integrated regulation) is associated with high quality learning and well-being. Autonomous self-regulated learning is therefore the desired drive for learning and can be supported by a teacher via satisfying the needs for autonomy, competence and relatedness. Conclusion: Extrinsic rewards and negative incentives should be avoided as they both undermine the intrinsic motivation. Autonomous self-regulated learning leads to more effective learning. Several practical tips that support one of the three basic psychological needs are discussed. Most are relatively easy to apply and stimulate autonomous self-regulated learning.
The permeability of natural fibre drains, capturing their micro-features
Authors: Nguyen Thanh Trung , Indraratna Buddhima
Published: May 2017

Natural fibres such as jute and coir are emerging as distinct alternatives to synthetic geomaterials, and in recent years they have been used increasingly for drainage and filtration in field applications. However, these naturally occurring materials are extremely variable in micro-characteristics such as the size, uniformity and shape of their fibres, while there is a lack of studies addressing how these differences can affect the hydraulic behaviour of fibrous media. This paper offers a laboratory study of the influence of micro-features on the hydraulic conductivity of fibre drain. Non-twisted and twisted fibre drains made from jute and coir were subjected to hydraulic conductivity testing and micro-analyses. Experimental results show a considerable contribution of the size characteristics of fibre to the hydraulic behaviour of the drain. A less-rounded shape of fibre and a larger twisting angle of the drain can increase the fluid–fibre contact area and the corresponding tortuosity of flow, which significantly reduces the drain permeability. The way in which the Kozeny–Carmen analytical approach can be adopted to predict the permeability of a fibre drain is discussed based on the experimental results, considering various micro-factors including the size of fibre, uniformity and the associated porosity.
Polycystic Kidney Disease without an Apparent Family History
Authors: Iliuta Ioan-Andrei , Kalatharan Vinusha , Wang Kairong , Cornec-Le Gall Emilie , Conklin John , Pourafkari Marina , Ting Ryan , Chen Chen , Borgo Alessia C. , He Ning , Song Xuewen , Heyer Christina M. , Senum Sarah R. , Hwang Young-Hwan , Paterson Andrew D. , Harris Peter C. , Khalili Korosh , Pei York
Published: May 2017

The absence of a positive family history (PFH) in 10%–25% of patients poses a diagnostic challenge for autosomal dominant polycystic kidney disease (ADPKD). In the Toronto Genetic Epidemiology Study of Polycystic Kidney Disease, 210 affected probands underwent renal function testing, abdominal imaging, and comprehensive PKD1 and PKD2 mutation screening. From this cohort, we reviewed all patients with and without an apparent family history, examined their parental medical records, and performed renal imaging in all available parents of unknown disease status. Subsequent reclassification of 209 analyzed patients revealed 72.2% (151 of 209) with a PFH, 15.3% (32 of 209) with de novo disease, 10.5% (22 of 209) with an indeterminate family history, and 1.9% (four of 209) with PFH in retrospect. Among the patients with de novo cases, we found two families with germline mosaicism and one family with somatic mosaicism. Additionally, analysis of renal imaging revealed that 16.3% (34 of 209) of patients displayed atypical PKD, most of which followed one of three patterns: asymmetric or focal PKD with PFH and an identified PKD1 or PKD2 mutation (15 of 34), asymmetric and de novo PKD with proven or suspected somatic mosaicism (seven of 34), or focal PKD without any identifiable PKD1 or PKD2 mutation (eight of 34). In conclusion, PKD without an apparent family history may be due to de novo disease, missing parental medical records, germline or somatic mosaicism, or mild disease from hypomorphic PKD1 and PKD2 mutations. Furthermore, mutations of a newly identified gene for ADPKD, GANAB, and somatic mosaicism need to be considered in the mutation-negative patients with focal disease.
Qualidade de vida das pessoas que vivem com o HIV/aids: estudo transversal
Authors: Hipolito Rodrigo Leite , De Oliveira Denize Cristina
Published: May 2017

Objetivo:  analisar  a  qualidade  de  vida  (QV)  e  suas  representações em  momentos  distintos  de  diagnóstico.  Método:  estudo  descritivo, transversal,  com amostra estratificada pelo tempo de diagnóstico composta por 100 pessoas soropositivas de  serviço  especializado  em  município  da  baixada  litorânea  fluminense.  Utilizaram-se formulários  sociodemográfico  e  de  saúde,  seguido  pelo  WHOQOL-HIV Bref  e  entrevista semiestruturada.  Empregou-se  análise  estatística  descritiva  e  inferencial.  A  análise lexical  foi  operacionalizada  pelo  software  Alceste.  Resultados:  a  percepção  da  QV  foi intermediária  em todos  os  domínios,  bem  como  os  conteúdos  da  representação  da  QV apontaram para a hipótese de representação não autônoma em relação à representação social da aids. Conclusão: constatou-se um perfil representacional da qualidade de vida tendente  para  aspectos  positivos  e  de  ressignificação,  apoiados  nas  novas  simbologias atribuídas  ao  objeto  aids.  É  necessário  considerar  a  satisfação  com a  saúde  e  o  maior tempo  de  diagnóstico  no  domínio  físico  como  aspectos  pertinentes  ao cuidado  de enfermagem.
Analysis of causes and clinical pattern of infertility in couples coming to a tertiary care centre in Bihar, India
Authors: Singh Kalpana , Kumari Rekha , Ranjan Alok , Bharti Geetam
Published: May 2017

Background: Infertility is one of the major health problems and a socially destabilizing condition for couples often causing marital disharmony. Infertility is defined as the failure to achieve a clinical pregnancy after 12 months or more of regular unprotected sexual intercourse. Worldwide, its prevalence is approximately 8-12%.There are numerous factors such as anatomical, physiological and genetic factors that cause infertility. Many environmental and acquired factors also lead to inability to conceive. Objective of the present study was to determine the causes and clinical pattern of infertility in infertile couples.Methods: It was a hospital based observational study carried out on 750 women in reproductive age group attending out-patient clinic of Reproductive Biology Department of Indira Gandhi Institute of Medical Sciences (IGIMS) at Patna during April 2013 to March 2017. All the cases of primary and secondary infertility diagnosed after full examinations and laboratory tests were included and cases lacking of full examinations and laboratory tests were excluded. All the data of infertile couples were recorded in a semi-structured Case Information Performa.Results: Out of 750 women 454 women had all the data and they participated in the study Nearly 68% women had primary infertility and rest had secondary infertility. Male factor was responsible in 37.39%, female factor in 20.48%, unexplained in 22.46% while a combination of both factor was seen in 8.37% cases in our study .135 women had irregular menstrual cycles in which 64(47%) had oligomenohhrea. 79% women had normal ultrasonography and nearly 11% of women had evidence of PCOD. 24% women had hypothyroidism (TSH more than 4.5 IU/L) and 59(13%) were found to have high level of prolactin i.e. >25 ng/ml. Nearly 8% of women had high level of FSH i.e. more than 10 IU/L which is an indicator of ovarian resistance. In nearly 16% women one fallopian tube was found blocked and 8% had both tubes blocked in hysterosalpingography. Husband semen analysis was done to assess male factor. Nearly 14% of their male partners suffered from azoospermia and 23% had at least one abnormal parameter in semen analysis.Conclusions: Etiological pattern of infertility varies in different parts of World. Male and female factors both are responsible for infertility. So, both the partners should be counselled and investigated properly.
Awareness of PCOS (polycystic ovarian syndrome) in adolescent and young girls
Authors: Upadhye Jayshree J. , Shembekar Chaitanya A.
Published: May 2017

Background: Polycystic ovarian syndrome (PCOS) is an endocrine disorder which affects the adolescent girls It affects 5% to 10% of women in their reproductive age. Awareness and accurate diagnosis is the first step in managing PCOS as it improves quality of life of the patient. The study was conducted to assess the knowledge on PCOS among the medical students.Methods: Survey of 200 girls was done to assess the knowledge on the polycystic ovarian syndrome among the medical students of different colleges studying in 1st, 2nd, and 3rd year. The data was collected from the students by using structured questionnaire.Results: In present study, 51% girls had normal BMI, 19.5% were overweight, 16.5% were obese while 13% were underweight. 33.5% females had acne, 16% had irregularity of menses, 5% had hirsutism while 2% had infertility. In present study, 33% adolescent and young girls had information about PCOS from teacher, 19% got information from friend, 11.5% got information from a doctor, 3.5% got information from newspaper while 5% got information from internet. 28% adolescent and young girls were unaware of PCOS.Conclusions: Thorough knowledge of the disorder and counseling for adolescents should be included in the curriculum which will provide awareness towards the disorder and lifestyle modification. Accurate diagnosis at a younger age may be a key.
Biological attributes and feeding potential of three dominant predators of Lipaphis erysimi (Kaltenbach)
Authors: Manpoong N. S. , Firake D. M. , Behere G. T. , Rajesh T.
Published: May 2017

Basic biological attributes and feeding potential of three major predators viz., the seven spotted lady bird beetle Coccinella septempunctata Linnaeus and two syrphids Episyrphus viridaureus (Wiedemann) and Betasyrphus isaaci (Bhatia), of mustard aphid, Lipaphis erysimi were studied under laboratory conditions. The predators were multiplied on mustard aphids reared on mustard plants. C. septempunctata, E. viridaureus and B. isaaci completed their life cycle in 68.5± 6.5 days, 47±2 and 41±2, respectively. Coccinella septumpunctata completed the larval growth with four larval instars, while both the syrphids terminated the larval growth with three instars. Final instars of all the three predators were found to have highest predatory potential than the younger instars. C. septumpunctata was found to be the most dominant predator of mustard aphid with average lifetime consumption of 4312±537.74 aphids, followed by E. viridaureus (416.67±6.76 aphids) and B. isaaci (338±7.89 aphids). All the three predators have the potential to reduce the mustard aphids; however, C. septumpunctata has a maximum predatory potential with a longer life, which makes this species as an excellent bioagent of L. erysimi and further research on their utilization on a large scale should be undertaken.
Beyond Petroleum: A look at the impact of electric cars in the three main cities of Ecuador
Authors:   Pontificia Universidad Católica de Ecuador, Maks Davis Michael
Published: May 2017

El propósito de este trabajo es estudiar el impacto del cambio de vehículos privados en las tres principales ciudades de Ecuador, y evaluar si la demanda de electricidad creada podría ser satisfecha por energías renovables ubicadas dentro de los límites de la ciudad. El trabajo estudia las tres principales ciudades del Ecuador: Quito, Guayaquil y Cuenca. Se encontró que en teoría y en el caso extremo, si hubiese un cambio repentino donde todos los autos y VUDs de Quito serían reemplazados por vehículos eléctricos, se crearía una demanda de electricidad que podría satisfacerse a través la energía solar fotovoltaica dentro los límites de la ciudad. Esto estaría en línea con la teoría del metabolismo urbano. Sin embargo, no sería factible, hacer esto a través de la energía eólica. En general, se reconoció que en la realidad habría una transición más lenta hacia el uso de vehículos eléctricos, que resolvería parcialmente la demanda de combustibles fósiles del sector de transporte, con poco impacto en la problemática de congestión y la demanda de espacio. Como tal, los sistemas de transporte colectivo y de transporte multimodal tienen un importante papel que desempeñar en este contexto para la siguiente etapa de la investigación.
Implicaciones de asumir constante la tasa libre de riesgo y la volatilidad en el modelo binomial para valoración de opciones
Authors: Castellanos Orejuela José Mauricio
Published: May 2017

El método utilizado por la ciencia financiera se ha centrado en la valoración (dar/establecer un precio) bajo el principio de no arbitraje, lo cual lleva al resultado conocido como Ley de Único Precio; siendo así como se establecen los resultados de modelos como el de Black-Scholes y el de Cox-Ross-Rubinstein, el cual es una excelente aproximación al modelo continuo, en donde se pueden analizar de forma simplificada los complejos conceptos inmersos en el modelo Black-Scholes. Sin embargo, la aplicación de algunos de los supuestos que hacen parte de este, que a través del modelo CRR se pueden analizar de forma simplificada, permiten que en la práctica se pueda arbitrar en los mercados de opciones europeas.
Degradação ambiental agropecuária e seus determinantes em Minas Gerais
Authors: Campos Samuel Alex Coelho , Gomes Marília Fernandes Maciel , Coelho Alexandre Bragança
Published: May 2017

O presente estudo determinou a importância da produção e das práticas adotadas pelos estabelecimentos agropecuários sobre a degradação ambiental nos municípios mineiros, em 2006. Para tal foi utilizado o Índice Geral de Degradação (IGD) e a regressão quantílica. As estimativas demonstram a importância das práticas agropecuárias, atividades agropecuárias e mecanização sobre a degradação. Pela análise, destacam-se: (i) o valor ótimo de utilização da rotação de culturas, do plantio em nível e da renovação de pastagens para o controle da degradação; (ii) a importância da reserva legal para o controle da degradação proveniente da agropecuária; e (iii) a importância da intensidade da produção agropecuária para a degradação. Ações de maior eficácia e eficiência para redução da degradação agropecuária podem ser propostas por meio dessas considerações.
Variations saisonnières de l’excrétion des oeufs de strongles par les chevaux en zone subhumide d’Algérie
Authors: Bentounsi B. , Maatallah F.
Published: May 2017

L’évolution saisonnière de l’excrétion strongylienne, chez des chevaux non vermifugés, au pré, dans la région côtière d’El Tarf, a été suivie par coproscopie et coproculture. L’excrétion des oeufs de strongles, essentiellement estivale et atteignant un pic unique en septembre, a clairement ressemblé aux cinétiques observées en Angleterre et en France. Dans les coprocultures, Strongylus vulgaris a dominé. S. vulgaris et S. edentatus ont été présents tout au long de l’année. Les larves 3 de S. equinus ont été très nombreuses en avril, suggérant un retour saisonnier des stades 5 dans le tube digestif. Les larves d’Oesophagodontus et de Triodontophorus ont été aussi assez constantes dans les coprocultures. L’excrétion des oeufs de Trichostrongylus axei a été saisonnière par son absence hivernale. Les oeufs de Cyathostominae ont été constamment excrétés, mais avec un net minimum entre mai et octobre.
Cysticercose bovine en Gambie
Authors: Unger F. , Münstermann S. , Carayol D. , Marcotty Tanguy , Geerts S.
Published: May 2017

Des recherches ont été menées dans les abattoirs d’Abuko et de Banjul ainsi que sur 391 bovins répartis sur 16 exploitations dans la région de Central River en Gambie. En utilisant des méthodes conventionnelles d’inspection de viande, 12 (0,75 p. 100) bovins sur 1 595 bovins abattus ont été trouvés infectés avec des cysticerques de Taenia saginata. Des recherches dans des fermes ont montré une séroprévalence des troupeaux de 21,3 p. 100 (CI95: 13,6; 29,0) en utilisant un test Elisa de détection d’antigène. Bien que les rapports officiels n’aient pas mentionné ces dix dernières années l’existence de la cysticercose bovine en Gambie, les résultats de cette étude mettent clairement en évidence la présence de cette zoonose dans le pays. La divergence entre les résultats des deux techniques est due à la faible sensibilité de l’inspection de viande classique et à la haute sensibilité de l’Elisa pour la détection d’antigène en circulation.
Prévalence sérologique de la peste des petits ruminants dans la province du Soum au nord du Burkina Faso
Authors: Sow A. , Ouattara L. , Compaoré Z. , Doulkom B. R. , Pare M. , Poda G. , Nyambré J.
Published: May 2017

Une enquête sérologique sur la peste des petits ruminants a été réalisée sur un échantillon de 2 114 sérums de petits ruminants provenant de 42 élevages des neuf départements de la province du Soum, située au nord du Burkina Faso. Sur l’ensemble des sérums analysés par c-Elisa, la prévalence sérologique de la PPR a été de 28,90 p. 100. L’étude a montré que cette prévalence variait d’un département à l’autre. Elle a été plus élevée chez les animaux âgés de plus de trois ans que chez les sujets plus jeunes (p = 0,042), chez les ovins (33,09 p. 100) que chez les caprins (23,01 p. 100) et chez les femelles que chez les mâles (p = 0,000). La circulation du virus de la PPR dans la province du Soum ayant été avérée, il apparaît nécessaire d’entreprendre des mesures vaccinales de lutte contre cette maladie.
Variabilité spatiale des captures de Culicoides dans des fermes de la zone de Bala au nord du Pays de Galles
Authors: Guis Hélène , Labuschagne Karien , Sugden David , McIntire K. M. , Vilar Maria J. , Baylis M.
Published: May 2017

The aim of this study was to investigate the spatial variability of Culicoides catches at a local scale using environmental data and farm characteristics. A thrice-replicated random sampling design was set up on a 1x1 km grid in a 6x6 km study site in Bala, North Wales in July 2008 over a period of 12 days using Onderstepoort black light traps to catch Culicoides. Overall, 132 catches were made on 35 farms, 32 of which were sampled three times and three of which were sampled daily. A total of 357,229 Culicoides encompassing 19 species (mean catch = 2706 per trap and per night; maximum catch = 65,763) were caught. The species of the Obsoletus complex accounted for 62% of the catches. Environmental factors (such as land cover, land use, soil type, altitude and weather) and farm characteristics (animals, insecticide use, dung management, proximity to water and to potential breeding sites, and openness of the landscape) will be used to model the abundance of Culicoides species. The influ­ence of Culicoides abundance in neighbouring farms will also be assessed and accounted for. This will help better understand spa­tial distribution and variability of Culicoides densities at a local scale and provide elements for discussion on how to approach mapping and modelling of vector abundance at coarser scales.
Foyers récents de peste équine africaine en Afrique du Sud
Authors: Venter Gert J. , Labuschagne Karien , Hermanides I. , Majatladi D. , Boikanyo S. , Wright I.
Published: May 2017

Based on diagnostic samples received at the Agricultural Research Council – Onderstepoort Veterinary Institute (ARC-OVI), a reference centre for African horse sickness (AHS) and bluetongue (BT) for the World Organisation for Animal Health (OIE), the traditional picture on the presence and occurrence of AHS seems to have changed dramatically in South Africa. Outbreaks of AHS virus (AHSV) have increased in this country over the last three to eight years. Outbreaks tend to occur earlier in the season than normally expected. Unpredicted outbreaks of AHS during the past five years in the declared AHS-free area in the South-Western Cape has led to the temporary closure of the quarantine station in Cape Town and the ban on horse exports from South Africa with significant losses to the horse industry as a whole. In January and February 2006, outbreaks of AHSV serotype 9 have also occurred in the George/Knysna area in the Western Cape. Outbreaks in this area occurred over a relatively long period and continued into the colder months of the year. This seems to indicate that AHSV has overwintered in this frost-free area, and that it could have occurred in cycling hosts (donkeys and zebras) and/or in adult Culicoides species. Since 2001, AHS has occurred annually in the Eastern Cape, South Africa, with at least four serotypes in circulation today. In an outbreak in April 2008 in Port Elisabeth, Eastern Cape, C. bolitinos was the dominant species in the coastal areas, whereas C. imicola was the dominant one in the inland area. In the outbreak in February and March 2008 in Robertson and in Kimberley, Northern Cape, C. imicola was the dominant species. Pools of midges have been tested for virus detection during each outbreak. From the outbreak in Robertson, 13 pools were posi­tive for equine encephalosis virus (EEV) and two for BTV. From the outbreak in Kimberley, EEV was isolated from one pool of C. tuttifrutti. The role of C. tuttifrutti as a vector is still poorly understood.