bluuebunny/crossref_metadata_2025 huggingface dataset:
Perspectivas da participação do público através de ONGs para a gestão ambiental na América Latina
Authors: Schütz Gabriel Eduardo , Freitas Carlos Machado de , Hacon Sandra
Published: July 2012

Este artigo analisa algumas perspectivas e limitações das organizações não-governamentais (ONGs) como instância de participação popular para a gestão ambiental local e regional na América Latina. Em primeiro lugar, é analisado o fundamento ético do trabalho voluntário independente nas democracias regionais e sua relação com a formulação de políticas públicas - principalmente nas áreas de saúde e meio ambiente - no processo de globalização da economia mundial. Este estudo também apresentada uma análise qualitativa de dados demográficos, socioeconômicos e ambientais que correlacionam a referência espacial das ONGs com as paradoxais realidades sociopolíticas e socioeconômicas do continente americano. Tenta-se mostrar que setores governamentais e do empresariado vêm estimulando a substituição da solidariedade compulsória das políticas sociais compensatórias pela filantropia e o trabalho voluntário, e que essa tendência é coerente com a reestruturação do capitalismo mundial. Os dados demonstram que, em geral, as ONGs não aparecem e prosperam na pobreza, mas nas áreas de concentração de poder político-econômico associado ao desenvolvimento humano. É discutida a diferença conceitual entre sociedade civil e terceiro setor, comumente identificados como sinônimos. Finalmente, são apresentadas conclusões que podem servir de estímulo para que gestores e o público em geral reflitam sobre o projeto político e econômico que está por trás do incentivo ao trabalho voluntário em áreas de responsabilidade do Estado, como são as áreas de saúde pública e gestão ambiental.
Importância dos arquivos empresariais para a pesquisa histórica em administração no Brasil
Authors: Coraiola Diego Maganhotto
Published: July 2012

Nos últimos anos, verificam-se crescente consciência e preocupação dos pesquisadores da área de Estudos Organizacionais com relação à importância da História e do desenvolvimento de pesquisas históricas para a compreensão dos objetos de estudo da disciplina. No entanto, qualquer pesquisa que se dedique a resgatar traços de situações, eventos e acontecimentos passados estará, necessariamente, restrita às reminiscências desse período. Dessa forma, qualquer clamor pela descoberta do passado precisa estar acompanhado de outro, que demanda também a preservação e disponibilização dos vestígios e fontes que lhe proporcionem acesso. Defende-se, como argumento central deste trabalho, a necessidade de discussão e avaliação da atual situação dos arquivos empresariais brasileiros, a fim de promover o desenvolvimento de ações e projetos de melhoria voltados à preservação e disponibilização de arquivos empresariais para a pesquisa na área de Estudos Organizacionais. Assim, o interesse no fortalecimento dos programas de preservação e dos empreendimentos dedicados aos arquivos empresariais brasileiros demanda que sejam equacionadas as possibilidades de contribuição de agentes públicos e privados. Estes integrariam seus esforços na construção de projetos e programas dedicados a recuperar documentos e registros sobre a história das organizações brasileiras, reunir e organizar adequadamente esses registros em coleções e arquivos bem estruturados, além de disponibilizar os acervos das diversas instituições dedicadas aos arquivos empresariais para a realização de pesquisas. Essa é uma etapa necessária e fundamental para garantir a disponibilidade de matéria-prima para pesquisas dedicadas a desvendar a história das empresas e do desenvolvimento da Administração no Brasil.
Modification of the ferrite phase in cements by manganese substitution
Authors: Puertas F. , Glasser F. P.
Published: July 2012

Synopsis

The effect of manganese substitution into the crystal structure of the ferrite phase, Ca2 (Fe2-x Alx)O5, has been studied by X-ray diffraction, analytical electron microscopy and differential thermal analysis. The introduction of manganese into Ca2Fe2O5 and Ca4Fe2Al2O10 produces a distortion of the crystal structure marked by an expansion of the b axis but without changes in crystallographic symmetry. The limits of solid solution of manganese in both phases were determined. The presence of manganese in the Ca2Fe2O5phase suppresses its ferromagnetic character.
The microstructure of tricalcium silicate/pulverized-fuel ash blended cement pastes
Authors: Rodger S. A. , Groves G. W.
Published: July 2012

Synopsis

The microstructure and composition of the reaction products in a C3S/pfa blended cement paste have been studied by analytical electron microscopy of thin sections. The presence of pfa does not significantly affect the morphology of the hydration products of C3S but the C/S ratio of the C-S-H is reduced in all areas. The reaction products of the pfa after one year are partial shells of hydrogarnet formed within the reacted zones of the pfa particles, radially fibrillar C-S-H within reacted zones and shells of dense C-S-H, the first forming immediately outside the pfa particle surface and later shells forming within the reacted zone by rhythmic precipitation. These two forms of C-S-H have similar C/S ratios, averaging between 1·4 and 1·5. Silica and alumino-silicate glass particles have similar reactivities.
The suitability of solvent exchange techniques for studying the pore structure of hardened cement paste
Authors: Thomas M. D. A.
Published: July 2012

An examination was made of the interaction between three organic solvents (methanol, propan-2-ol and ethanol) and samples of calcium hydroxide and of hardened cement paste. The techniques used were thermogravimetric analysis, X-ray diffraction, infra-red spectroscopy and mercury intrusion porosimetry. Although there was evidence of a reaction between the solvents (particularly methanol) and cement paste during thermal analysis, there was no indication of a reaction at room temperature. The pore size distribution of vacuum-dried cement samples was unaffected by methanol soaking, and it is concluded that solvent exchange techniques are suitable for the preparation of samples for pore structure determinations.
Influence of sulphonated melamine formaldehyde superplasticizer on cement hydration and microstructure
Authors: Yilmaz V. T. , Glasser F. P.
Published: July 2012

This Paper assesses the role of sulphonated melamine formaldehyde (SMF) in cement. It is shown that the data given in the literature are frequently in error due to inappropriate analytical procedures. Initial rapid sorption of SMF occurs, probably on an ettringite precursor. This is followed by partial desorption of SMF, but eventually the alkaline nature of the cement pore fluid precipitates a chemically altered derivative for which some analytical data are given. The retarding effect of SMF is pronounced at 20°C but diminishes or disappears with increasing temperature up to 55°C. In comparable paste specimens SMF reduces the mean size of Ca(OH)2 crystallites and alters their morphology, but promotes the growth of larger ettringite crystals.
Properties of organo-mineral cements
Authors: Nägele E. , Schneider U.
Published: July 2012

Alkali silicates react with isocyanates to form hard and brittle materials. The mechanical properties of these organo-mineral cements depend on the types of sodium silicate and isocyanates that are combined, and on the accelerating and modifying agents that may be added. The flexural strength of the pure hardened cements can reach 10 M Pa, and the compressive strength 30 M Pa. The setting times vary from a few seconds to several weeks. The hardened cement seems to be an intimate mixture of at least two phases: an organic phase consisting of a polyisocyanate resin, and an inorganic phase consisting mainly of an amorphous silica gel and various carbonates of alkali and earth alkali metals. Thus, the hardening process takes place simultaneously in the two phases. The isocyanates react to a polymeric material, liberating CO2. This in turn acts as a catalyst for the setting of the alkali silicates, yielding an SiO2 gel and various carbonate phases as reaction products. Five different carbonates have so far been identified. The paper summarizes results obtained to date in a current research programme sponsored by the German Research Foundation for pure organo-mineral cements and some mortars made therefrom.
Effect of the states of chromium ion on the colour characteristics of doped β-C2S
Authors: Xiuji Feng , Peiyu Yan
Published: July 2012

The state of chromium ions in β-C2S was studied according to crystalfield theory by optical spectroscopy and electron paramagnetic resonance. The energy levels of chromium ions were calculated. These ions exist in the form of Cr4+ and Cr5+, co-ordinated in distorted octahedra. The coloured β-C2S hydrate fades because the level of tight absorption decreases due to the valence change of chromium ions as chromium is leaked.
The effect of in situ polymerization on the chloride diffusion and microstructure of polymer-Portland cement pastes and mortars
Authors: Bentur A. , Diab H. , Ben-Dor L. , Heitner-Wirguin C.
Published: July 2012

A polymer-cement system was produced by in situ polymerization of vinyl sulphonate in Portland cement pastes and mortars. The effects of the polymer on strength, chloride diffusion and microstructure were studied. The presence of polymer was found to be extremely effective in reducing chloride diffusion, but was accompanied by a reduction in strength. The addition of silica fume in combination with the polymer was found to be effective in mitigating the reduction in strength, while providing additional benefits with regard to chloride diffusion. The beneficial effect of the silica fume wasfound to be associated with its influence on the polymer phase, which became more coherent and more compatible with the matrix.
Interstitial material in oilwell cements: evidence from X-ray microanalysis
Authors: Bergstrom T. B. , Hall C. , Scrivener K. L.
Published: July 2012

New X-ray microanalysis data are reported on the composition of the interstitial material in a set of eight oilwell cement clinkers and one ordinary Portland cement clinker used as a comparison. Results on the OPC clinker support the aluminate and aluminoferrite phase compositions proposed by Taylor. In the oilwell cements, the interstitial composition varies considerably from point to point. For clinkers with bulk MgO < 1·5% approximately, the compositions scatter along the line joining the Taylor ferrites. In clinkers with MgO > 1·5% the compositions deviate from the Taylor line towards lower Fe contents. The results are evidence for non-uniform aluminoferrite solid solution or fine-grained (submicron) mixtures of aluminoferrites. There was no evidence of discrete tricalcium aluminate in regions large enough for reliable microanalysis. The degree of Mg substitution in the interstitial material follows the bulk MgO concentration. The Taylor aluminoferrite phase compositions can be generalized to allow for Mg, Si and Ti substitution. The generalized alumina ratio of the interstitial material and the degree of substitution vary considerably from clinker to clinker.
Relative importance of deleterious reactions in concrete: formation of AAR products and secondary ettringi te
Authors: Shayan A. , Quick G. W.
Published: July 2012

Aggregates, varying in alkali reactivity, were used for making mortar bars and concrete prisms, employing the same Portland cement. Measurement of length changes of the specimens was carried out under various storage conditions and for different lengths of time. Scanning electron microscopy of the specimens and energy-dispersive X-ray analysis of the products formed in them has shown that alkali-aggregate reaction (AAR) products develop first and much faster than ‘secondary’ ettringite (mat-form, filling cracks) associated with some deteriorated steam-cured concrete elements. The expansion and cracking due to AAR was more rapid and extensive at higher temperature (80°C) than at lower temperature (40°C). Mat-forms of ettringite developed only after prolonged storage of the specimens in a fogroom, and the amount was larger in the specimens initially treated at 80°C, mainly because more AAR expansion and cracking occurred at the higher temperature, but also because the higher initial temperature caused larger formation of secondary ettringite. It is concluded that AAR products were primarily responsible for the expansion and cracking that occurred in the specimens containing reactive aggregates. The formation of ettringite was not involved in this deterioration, but it may have had a secondary role at later ages. The deterioration of some steam-cured concrete railway sleepers may be explained based on these results.
Pozzolanic activation of metakaolin
Authors: De Silva P. S. , Glasser F. P.
Published: July 2012

Metakaolin may be calcined without grinding and suitably activated by Ca(OH)2, Na2SO4, CaSO4 (beta anhydrite) and/or NaOH. The best strengths, 50 MPa from mortar cubes at 18 months, were obtained using Ca(OH)2 and CaSO4 activators. The handling and set properties are similar to those of Portland cement; aluminous C-S-H gel is the best binder. All compositions contain K+ derived from mineral impurities in kaolin, thus the performance and activation of kaolins may depend partly on their alkali content. The microstructures of the cured products are described, and the importance of good space filling by the hydrates is emphasized. Since the precursor minerals are widely distributed, kaolin deserves more investigation as the principal component of low-energy binder systems.
TEM study of the composition of the interstitial phase in an oil-well cement clinker
Authors: Richardson I. G. , Hall C. , Groves G. W.
Published: July 2012

The interstitial phase of an oil-well cement production clinker was examined by analytical transmission electron microscopy. The predominant interstitial component was a ferrite of varying composition, the Fe: Al ratio varying from a low value to 2, and values most commonly in the range O·7-2. A substantial variation in composition sometimes took place over quite short distances. Displacement faults were found in the ferrite, and these appeared to be associated with relatively iron-rich regions of the ferrite. Small regions of C2S, MgO and non-cubic C3A were also found in the interstitial phase of the clinker.
Investigation of solid and aqueous chemistry of lO-year-old Portland cement pastes; with and without silica modifier
Authors: Atkins M. , Lachowski E. E. , Glasser F. P.
Published: July 2012

Mature cement specimens, cured in controlled conditions, provide a valuable source of data which can be used to verify or develop models, based on thermodynamic equilibrium. Four 10-year-old cement pastes were subject to detailed examination of their chemistry: OPC, OPC + 15% microsilica, HAPC (high alkali Portland cement), and HAPC + 15% microsilica. The solid phases were analysed by analytical electron microscopy (AEM), thermogravimetry and X-ray diffraction. The aqueous phase was characterizedfor its content of Na, K, Ca, Mg, Si, Al and SO4. AEM showed considerable variation in the Ca/Si ratio of C-S-H within paste samples, indicating persistent compositional disequilibrium. Ca/Si ratios were noticeably lower in the silica-modified pastes, although the mean values were not statistically different; 1·54 ± 0·21 in OPC, compared to 1·36 ± 0·19 in OPC + 15 % microsilica. The presence of microsilica also favours the formation of AFt at the expense of AFm, some of this AFt being relatively Si-rich. Soluble alkali is considerably reduced in the silica-modified pastes owing to the increased amounts of low ratio C-S-H from pozzolanic reaction. Thermodynamic modelling of the aqueous phase shows, in general, good agreement between observed and predicted solubilities. Two areas of weakness were identified: solid solution phenomena may significantly alter the solubility properties of host phases; there is also a lack of a robust thermodynamic model for C-S-H in cement pastes.
Effect of phosphate additions on the hydration of Portland cement
Authors: Ma Weiping , Brown P. W.
Published: July 2012

New cementitious compositions have been sought by reactions involving ordinary Portland cement and sodium and calcium phosphates. The phosphate-modified cements produce more heat and exhibit much faster hydration rates than does OPC. The phosphate-containing products formed at room temperature are X-ray amorphous, but scanning electron microscopy shows that the hydration of OPC modified by different phosphates can result in morphologically distinct hydration products. Hydrothermal treatment at 160°C of OPC modified by CaHPO4 leads to phase transformations of a poorly crystalline phosphate containing product phase into crystalline hydroxyapatite. Generally, the presence of sodium and calcium phosphates resulted in improved flexural strengths; an exception was when (NaPO3)n·Na2O was used. The effects of different factors on the mechanical properties in the OPC-phosphate system are discussed. These factors include the effects of different sodium and calcium phosphates, processing by warm pressing, w/c ratio, and curing conditions.
Autogenous relative humidity change in silica fume-modified cement paste
Authors: Jensen O. M. , Hansen P. F.
Published: July 2012

Even during sealed curing, the relative humidity (RH) within a hardening cement paste may decrease. This self-created change in the RH (autogenous RH-change) may be so forcible that the cement paste cracks if the attached deformation is restrained. This Paper focuses on the influence of silica fume (SF) addition on autogenous RHchange in hardening cement paste. Continuous measurement of autogenous RH-change for more than 1½ years has shown it to be markedly increased by SF addition.
Characterization of Australian and New Zealand fly ashes for concrete manufacture
Authors: Jo Y. M. , Guang D. , Raper J. A.
Published: July 2012

The disposal of fly ash produced by modern thermal power stations is an enormous environmental problem, which can be alleviated to a small degree by using the fly ash as a cement additive in the manufacture of concrete. In order to assist the assessment of the feasibility of such utilization, chemical and physical properties of nine different Australian and New Zealand fly ashes were determined with the purpose of relating them to the pozzolanic properties of the ashes. It was found that, while the ashes produced from bituminous and subbituminous coal were generally (apart from the Tarong ash) acceptable as a pozzolanic source, two of three tested ashes produced from brown coal did not meet the required standards. Some ashes, in particular the Loy Yang ash, were found with some additional treatment to be potential pozzolanic additives.
Distribution of pore sizes in white cement paste from proton NMR spin-lattice relaxation
Authors: Best G. , Cross A. , Pintar M. M. , Blinc R.
Published: July 2012

The distribution of pore sizes in hardening white synthetic cement paste, after 100 h of hydration, is modelled using proton spin relaxation data. The results are consistent with a trimodal pore size power law distribution. Two different distribution functions obtained by small angle neutron scattering were employed: one obeys a power law r-a with a = 4·5 for the pores with diameters of 20-120 nm, and one obeys a power law with a = 3·8 for pores having diameters of 120-2600 nm. The third pore group obeys the same power law (a = 3·8) for pores with diameters of 2·6-14 μm.
Long-time monitoring of the microstructural change in hardening cement paste by SANS
Authors: Häussler F. , Hempel M. , Baumbach H.
Published: July 2012

Hydrating cement. paste is an essential part of concrete because its structure largely determines the physical properties of concrete (e.g. its strength and durability). Small-angle neutron scattering (SANS) investigations were used to obtain a non-destructive description of statistically representative microstructures (nanometre and micrometre scale). The results obtained illustrate the possibilities of using SANS to monitor the time-dependent microstructural changes that occur during the hydration process. All samples were made from ordinary Portland cement (OPC) with a water/cement ratio of 0·38. By controlling the volume ratio of D2O in the hydration water (Cdw), a variation in contrast is achieved. In the special case of Cdw = 0·38 the scattering length densities of the hydration products are nearly homogeneous and the contrast between them is drastically reduced. In order to study the influence of the hydration conditions, the sample thickness, temperature, the size fraction of the cement clinker and Cdw were varied. The hydration products and inner surfaces formed by the separated microstructural objects were found to show a fractal behaviour. The fractal dimension obtained from the scatt~ring curves reflects the microstructural changes that occur during the hydration process within the size range of a few nanometres up to a few micrometres, depending on the chosen hydration parameters. In this size range the SANS effect is dominated by the hydration products.
Zinc oxide in cement clinkering: part 1. Systems CaO—ZnO—Al2O3 and CaO—ZnO—Fe2O3
Authors: Bolio-Arceo H. , Glasser F. P.
Published: July 2012

The systems CaO—ZnO—Al2O3 and (C—Z—A) and CaO—ZnO—Fe2O3 (C—Z—F) have been studied and their phase relationships established. Two hitherto unreported phases, Ca3ZnAl4O10 (C3ZA2) and Ca6Zn3A14O15 (C6Z3A2) were characterized in the system C—Z—A: their X ray diffraction patterns were obtained and indexed. No new phases were discovered in the system C—Z—F Phase coexistence has been established in both systems. C6Z3A2 is of particular interest to clinkering because it coexists with alite, belite and a c~lnker liqUid phase: This. is confirmed both by laboratory experiment and its identification in white and grey clinkers, made from industrial raw meals doped with 1·0 and 2·0 wt% of zinc oxide.
Immittance response of cementitious binders during early hydration
Authors: Starrs G. , McCarter W. J.
Published: July 2012

The current work focuses on the application of a.c. impedance spectroscopy techniques to cemenfltlOus systems while still in the liquid state (i.e. during the dormant period). A variety of formats of data presentation are presented and exploited to understand the origins of polarization processes within these systems. The theoretical treatment also allows simulation of the experimental data to provide an interpretation of the bulk impedance response. Data are obtained over the frequency range 1 Hz to 20 MHz, but interpretation and analysis is focused, in the main, on the range 1 kHz to 1 MHz.
The permittivity and conductivity of concretes at ground-penetrating radar frequencies
Authors: Shaw M. R.
Published: July 2012

A full understanding of the behaviour of ground-penetrating radar pulses as they propagate through concrete structures requires knowledge of the variation of the permittivity and conductivity of the concrete across the frequency spectrum of the radar pulse. Variations in concrete composition and the fractional water content can effect these electrical properties. This paper describes a large-diameter transmission line that can accommodate removable concrete specimens and the various methods that have been used to analyse frequency domain reflection and transmission measurements on the transmission line up to a maximum frequency of 1 GHz. The effects of fractional water content, ordinary Portland cement strength, cement replacement and lightweight aggregates are considered. The effects of high water contents on radar pulse shapes are illustrated to demonstrate the effects of frequency-dependent electrical properties.
Discretized conductivity measurements to study wetting and drying of cover zone concrete
Authors: McCarter W. J. , Chrisp T. M. , Ezirim H. C.
Published: July 2012

In situ electrical measurements are used in conjunction with surface-applied, volumetric gain methods to study cover zone concrete under a wetting and drying regime. Ordinary Portland cement (OPC) concretes and OPC with partial replacement with ground granulated blast-furnace slag were used in the experimental programme with samples exposed to water and chloride solution. Monitoring the variation of electrical properties at discrete points within the surface 50 mm, during absorption and after drying, provides information on water and ionic penetration into the cover zone; drying response, and evidence of continuing hydrationlchloride-binding effects.
Ion transport in cement paste during electrochemical chloride removal
Authors: Tritthart J.
Published: July 2012

To clarify open questions regarding the mechanism of electrochemical chloride removal (ECR), changes in the concentration of chloride (Cl-), hydroxide (OH-), sodium (Na+) and potassium (K+) occurring during the flow of electric current in the pore solution and of Cl-, Na+ and K+ in the solids of different zones in cement paste samples were measured. The electrochemical reaction that occurred at the electrodes resulted in a marked increase in the OH- concentration of the pore solution in the zone of the sample close to the cathode, whereas a steep decrease was observed in the zone of the sample facing the anode. These changes had different effects on the transport of chloride. In the zone towards the cathode, the rising OH- concentration caused more and more of the total current to be transported by the OH- ions as the migration progressed in time (chloride removal became much less efficient here), while in the peripheral zone towards the anode more and more current was transported by the Cl- ions (chloride removal became more efficient here). This resulted in a change of chloride concentration in the pore solution and the solids, which was in disagreement with the direction of migration of these ions. According to the direction of migration, the Cl- concentration should have decreased most slowly in the peripheral zone towards the anode, because the Cl- ions leaving the sample at this point can be replaced by others that have moved in from the zone of the sample closer to the cathode. In the case of the alkali ions sodium and potassium, the changes in concentration were in agreement with the direction of migration.
Notice of retraction
Authors: Urednistvo U
Published: July 2012

(retraction) Based on the decision of the Editorial Board of the journal ?Serbian Archives
of Medicine? made at the meeting of the members of the Editorial Board June
7th, 2012, the following article is retracted from the ?Serbian Archives of
Medicine?, because it is an exact translation from English to Serbian
language of an original paper by other authors published in a foreign
journal (?blatant plagiarism?): Sindrom sistemskog zapaljenjskog odgovora
kod hirurskih bolesnika sa sepsom Dragan J. Milic, Miljko A. Pejic, Sasa S.
Zivic, Aleksandar D. Karanikolic, Slobodan Jovanovic, Milan Radojkovic
Srpski arhiv za celokupno lekarstvo, 2004, vol. 132, br. 5-6, str. 182-186
DOI: 10.2298/SARH0406182M

 Link to the retracted article 10.2298/SARH0406182M
Nanogratings in fused silica: Formation, control, and applications
Authors: Richter Sören , Heinrich Matthias , Döring Sven , Tünnermann Andreas , Nolte Stefan , Peschel Ulf
Published: July 2012

The authors investigated the formation of periodic subwavelength structures, so-called nanogratings, in the volume of fused silica. These self-organized structures emerge upon irradiation with ultrashort laser pulses, undergoing three distinct stages of growth from randomly distributed nanostructures to extended domains with uniform periodicity. The experiments revealed that the cumulative action of subsequent laser pulses is mediated by dangling-bond type defects. On shorter time scales, transient self trapped excitons may significantly enhance the formation process. Nanogratings exhibit an extremely large temperature stability up to 1150 °C. In combination with the possibility to precisely tune their form birefringence, nanogratings provide a powerful tool to realize, thermally stable complex phase elements.
Profile of visual impairment in children attending low vision clinic of Nepal Eye Hospital
Authors: Sapkota Kishore , Rajkarnikar Sagar , Shrestha Bina , Panthi Shyam , Pokharel Archana
Published: July 2012

Introduction: Visual impairment (VI) in children accounts for great challenge in the life of children that leads to greater medical, psychological, social and economic problems since the child has to live up with handicap for many years to come. Identifying the main causes of visual degradation and their pattern will help in preventive measures, early diagnosis, treatment and rehabilitation of vulnerable population. The aim of this study was to find out the pattern of visual impairment in children attending low vision clinic of Nepal Eye Hospital. Methods: A retrospective cross--sectional review of hospital records of all VI children att ending the low vision clinic from 1st May 2010 to 31st April 2011 with age less than 16 years was done. Results: Overall, 65 children were included in this study with mean age 11.58±3.83 years. Among them 55.4% were male. More than one third (34%) of the total children were in the category of blindness. More than two thirds (72.30%) patients had refractive error. Majority of the patients (66.15%) had multiple causes of visual impairment. Major causes of visual impairment were nystagmus (58.46%), high refractive error (26.15%) and amblyopia (24.61%). Low vision devices were prescribed for only 18.46% of the total patients. Telescope was the most frequently prescribed low vision optical device. Conclusion: Nystagmus, high refractive error and amblyopia were the main causes of VI. Most of the cases had multiple causes. Low vision devices were prescribed for very few of the visual impaired patients and telescope was the most frequently prescribed among them. DOI: http://dx.doi.org/10.3126/mjsbh.v10i2.6458Medical Journal of Shree Birendra Hospital July-Dec 2011 10(2) 18-21
Could Early Antiretroviral Therapy Entail More Risks than Benefits in Sub-Saharan African HIV-Infected Adults? A Model-Based Analysis
Authors: Anglaret Xavier , Scott Callie A , Walensky Rochelle P , Ouattara Eric , Losina Elena , Moh Raoul , Becker Jessica E , Uhler Lauren , Danel Christine , Messou Eugene , Eholié Serge , Freedberg Kenneth A
Published: July 2012

Background

Initiation of antiretroviral therapy (ART) in all HIV-infected adults, regardless of CD4+ T-cell count, is a proposed strategy for reducing HIV transmission. We investigated the conditions under which starting ART early could entail more risks than benefits for patients with high CD4+ T-cell counts.

Methods

We used a simulation model to compare ART initiation upon entry to care (‘immediate ART') to initiation at CD4+ T-cell count ≤350 cells/μl (‘WHO 2010 ART') in African adults with CD4+ T-cell counts >500 cells/μl. We varied inputs to determine the combination of parameters (population characteristics, conditions of care, treatment outcomes) that would result in higher 15-year mortality with immediate ART.

Results

The 15-year mortality was 56.7% for WHO 2010 ART and 51.8% for immediate ART. In one-way sensitivity analysis, lower 15-year mortality was consistently achieved with immediate ART unless the rate of fatal ART toxicity was >1.0/100 person-years, the rate of withdrawal from care was >1.2-fold higher or the rate of ART failure due to poor adherence was >4.3-fold higher on immediate than on WHO 2010 ART. In multi-way sensitivity analysis, immediate ART led to higher mortality when moderate rates of fatal ART toxicity (0.25/100 person-years) were combined with rates of withdrawal from care >1.1-fold higher and rates of treatment failure >2.1-fold higher on immediate than on WHO 2010 ART.

Conclusions

In sub-Saharan Africa, ART initiation at entry into care would improve long-term survival of patients with high CD4+ T-cell counts, unless it is associated with increased withdrawal from care and decreased adherence. In early ART trials, a focus on retention and adherence will be crucial.
Retrouver la croissance
Authors: Daniel Jean-Marc
Published: July 2012

Résumé Les commentaires sur l’actualité économique souffrent d’approximations techniques, d’une difficulté à hiérarchiser les problèmes et d’un manque de recul historique. Pour Jean-Marc Daniel, il convient de regarder la situation française sur la base d’une analyse cyclique de l’économie. Il convient alors de stimuler la productivité par la concurrence, l’innovation et d’exclure l’inflation, la dévaluation, le néo-mercantilisme et le protectionnisme.
Le renouveau de la philanthropie
Authors: Vaccaro Antoine
Published: July 2012

Résumé La philanthropie, pratique désuète de riches soucieux d’apaiser leur conscience ou impérieuse nécessité quand on ne peut plus compter sur l’État-providence ? En tout cas, les choses changent : collectes de dons en hausse, arsenal législatif et fiscal adapté aux entreprises, formes nouvelles de fondations, passerelles entre le monde de la générosité et celui de l’économie sociale et solidaire. Cela concourt à redéfinir les contours d’une pratique multiforme pour rendre le monde un peu plus vivable.
Correlation between knowledge of HIV, attitudes and perceptions of HIV and a willingness to test for HIV at a regional hospital in KwaZulu-Natal, South Africa
Authors: Orisakwe Emeka E. , Ross Andrew J. , Ocholla Peter O.
Published: July 2012

Background: With millions of South Africans infected with human immunodeficiency virus (HIV) and less than 10% of the population aware of their HIV status, HIV counselling and testing (HCT) is the first step in any attempt to reduce the number of new infections. For those who test negative, HCT personalises the risks and reinforces preventative messages whilst for those who are positive, it is the gateway to accessing counselling and care. The Health Belief Model postulates that knowledge and attitude influence behaviour. The aim of this study was to determine whether knowledge of HIV and the attitude of patients referred for HCT correlated with a willingness to test for HIV.Methods: One hundred and seventy two patients referred for HCT were randomly selected over a three month period. Data were collected by a research assistant using the modified standardised World Health Organization (WHO)–Global AIDS Project (GAP) questionnaire.Results: Ninety per cent of the participants demonstrated sound knowledge of HIV, acquired immune deficiency syndrome (AIDS) and HCT. Despite the 90% of the participants with sound knowledge only 71.5% of the participants tested for HIV. There was no statistically significant difference in knowledge between those who tested and those who did not test for HIV. Twenty five per cent of those who refused to test stated that they had already made up their mind not to test for HIV before the counselling session.Conclusions: Despite excellent knowledge of HIV, a significant number of patients referred for HCT do not test for HIV.
Implementing the Transition to Sustainable Development
Authors: Lambin Eric
Published: July 2012

From 1890 to 1990, the world population increased four times over while consumption of industrial products grew 40 times, energy consumption 16, water consumption 9 and the total size of the economy 14 times. Thanks to his creativity, man has the power to innovate and adapt his technologies, socio-political institutions and attitude towards respect for Nature in order to alleviate pressure on the environment. Markets in general do not take into account the value of many goods and services which are provided by Nature (such as the pollination of plants by insects, the regulation of floods by vegetation cover, the decomposition, by bacteria, of waste and toxic waste released into the water and soil, or the aesthetic value of the landscape) The successful transition to sustainable development requires the combination of sound information on the state of the environment, motivation turned into action and capacity to do so.
Anormalidades electroencefalográficas en pacientes pediátricos hondureños con desnutrición proteico-energética: un estudio de casos y controles
Authors: Solano Miguel , Medina Marco Tulio , Hernández Rebecca , Lara José
Published: July 2012

Se tienen como objetivos determinar y caracterizar los hallazgos electroencefalográficos en pacientes pediátricos con desnutrición proteico energética, utilizando un estudio de casos y controles. Se diseñó un estudio analítico-descriptivo con un grupo de pacientes y un grupo de controles sanos. Se realizó en el período comprendido de Febrero 2007 hasta Junio 2008.Se recolectaron los pacientes en una escuela localizada en un población marginal de Comayagüela. Se captaron 40 pacientes con desnutrición e igual número de controles sanos. Se realizó una evaluación antropométrica, neurológica y laboratorial. Se efectuaron registros de EEG digital en ambos grupos, siendo evaluados en forma ciega por dos médicos neurofisiólogos clínicos. Un 42% de los pacientes con desnutrición protéico- energética mostraron actividades electroencefalográficas anormales (P=0.0000045): a) Actividad epileptiforme focal en un 20%, b) Actividad lenta focal en un 15%, c) Actividad epileptiforme generalizada en un 12.5%, d) Actividad lenta generalizada en un 10%. Los grupos etarios más afectados fueron los que comprendían las edades entre 6- 9 años. Se encontraron frecuentes alteraciones en el trazado electroencefalográfico de los pacientes con desnutrición protéico-energética; alcanzando un 42% en comparación al grupo de controles sanos. DOI: http://dx.doi.org/10.5377/rct.v0i8.698 Revista Ciencia y Tecnología, No. 8, junio 2011 pp.21-38
Efecto gradiente del calentamiento global
Authors: Vivas César Mauricio Urbizo
Published: July 2012

Este artículo presenta al lector un estudio sobre el calentamiento global bajo el enfoque de la termodinámica. Al aplicar las leyes de este enfoque se describe el mecanismo termodinámico del cambio climático. A partir de criterios físicoquímicos, se descubre el calor residual o de desecho como otro posible factor causante del aumento de la temperatura global. Lo anterior se ha denominado "Efecto Gradiente de Calor en la Atmósfera". Además, se explica la razón del por qué algunos gases contribuyen al calentamiento global. También se analiza la influencia que tienen las energías alternativas en este fenómeno. DOI: http://dx.doi.org/10.5377/rct.v0i8.700 Revista Ciencia y Tecnología, No. 8, junio 2011 pp.62-73
Prevalencia de anemia en escolares de primer grado de 8 escuelas públicas de Tegucigalpa M.D.C., Honduras. Año 2009-2010
Authors: Rivera Rebeca , Rivera María Félix , Rivera Ivette C , Lanza Carmen
Published: July 2012

El objetivo de este trabajo es determinar la prevalencia de anemia en escolares de primer grado en 8 escuelas públicas de Tegucigalpa MDC. Ésta es una investigación de tipo descriptivo transversal. Se inició en el año 2009 y finalizó en 2010. El universo fueron todos los escolares matriculados en primer grado de escuelas 8 públicas de Tegucigalpa MDC. La muestra consistió en 450 escolares; un muestreo por conglomerados distribuidos en 8 escuelas del perímetro de Tegucigalpa. Cada escolar fue identificado por su nombre, edad, sexo y el nombre de la escuela. Como criterios de anemia se consideraron parámetros de la Organización Mundial de la Salud (OMS): Hemoglobina (Hb) < 11.5 g/dl, hematocrito < 34% en el grupo etario de 5 a 11 años. Para la evaluación de la gravedad de anemia se tomó como criterio los parámetros del Grupo Consultivo Internacional sobre Anemia Nutricional: “anemia leve” valores de 10 a 11.9 g/dl de Hb, “anemia moderada” entre 9.9 y 7.0 g/dl y “anemia severa” menor de 7.0g/dl de Hb. Fueron encuestados 453 escolares con una media de edad de 6.66 años (SD= 1.01 años), razón de M:F = 1.1:1.0 en cuanto a sexo. La prevalencia de anemia fue de 8.7% (Hb menor de 11.5 g/dl) con un IC(95%) = 5.6% a 10.8%. Se encontró que el 17.2 % de los escolares tenían hemoglobina entre 11.5 g/dl y 11.9 g/dl, con categoría de anemia leve a excepción de una escolar que tenía niveles de hemoglobina de 8.8 g/dl considerada como anemia moderada. Ningún escolar padecía de anemia severa. La anemia en los niños incide directamente en el rendimiento escolar y en la calidad de vida, por lo que es una problemática de primera importancia que puede ser prevenible e intervenida. Las autoras enfatizan la importancia de determinar la etiología multifactorial de las anemias para desarrollar programas de control efectivos. DOI: http://dx.doi.org/10.5377/rct.v0i8.701 Revista Ciencia y Tecnología, No. 8, junio 2011 pp.74-81
El tejido discursivo de una subjetividad Notas sobre la identidad
Authors: Barahona Miguel
Published: July 2012

El objetivo de este escrito es presentar la identidad, ciudadanía y globalización desde una perspectiva del esencialismo teórico, desarrollándolo dentro de una totalidad emancipada. La identidad demanda conocer las particularidades desde la representación de la nación, la cultura, el género y la etnicidad, entre otras; por lo que se ha conformado una propuesta reivindicativa dentro de las coordenadas y visiones particulares de diferentes autores. En tal sentido, a medida que se desarrollen los temas, se acercará al límite de la crítica donde el terreno de la argumentación se esgrime desde el sentido de la reinterpretación misma que se aproxima a una evidencia y a una redefinición de la misma producción identitaria. DOI: http://dx.doi.org/10.5377/rct.v0i8.702 Revista Ciencia y Tecnología, No. 8, junio 2011 pp.82-92
Neoliberalismo y conflictos socioambientales en Honduras: Cuatro casos de estudio: agua, bosque, explotación minera y agricultura
Authors: Martínez Luis Manuel
Published: July 2012

Con la implementación en Honduras del neoliberalismo desde la década de los noventa, los conflictos clasistas tendieron a invisibilizarse; tomando diversas formas atomizadas de lucha en las que otros actores sociales antes no involucrados se incorporaron para la defensa de espacios que previamente no eran reconocidos como espacios de conflicto o si lo era pasaban desapercibidos. El presente trabajo pretende analizar, a partir de cuatro de los principales conflictos socioambientales suscitados en las últimas dos décadas en Honduras, cómo los actores sociales involucrados construyen espacios de interacción que pretenden generar cambios sociales en la protección del bosque, el agua, explotación minera y agricultura Para comprender de manera más exacta esta situación, es pertinente recordar que dos de los pilares del neoliberalismo radican en la liberalización del comercio y de las inversiones, así como la privatización (Friedman, 1992). Por ende, el deterioro de un Estado medianamente fuerte, durante las décadas precedidas, tributó en la adjudicación de valores de cambio; elementos que antes eran de acceso universal como el agua y los bosques. Al agregar el factor privatización, el Estado se desprende totalmente de estos recursos y los sede a actores de las nuevas élites económicas que se unen a las tradicionales y transnacionales que poseen tierras y minas conformándose una élite político- económica. De hecho, estos contextos de conflictividad generaron revueltas espontáneas que progresivamente tomaron formas organizativas particulares en cada uno de los casos. Así surgen iniciativas como el MAO, CAVS, MUCA y el CNRP. A la luz de la teoría de los nuevos movimientos sociales, este trabajo pretende aportar insumos metodológicos para el análisis ecléctico y más holístico de estas nuevas formas de organización social que pretenden desarrollar cambios; partiendo de experiencias locales y problemas particulares. Así bajo este mismo enfoque teórico se pretenden identificar los límites y alcances de estas formas de acción colectiva. DOI: http://dx.doi.org/10.5377/rct.v0i8.703 Revista Ciencia y Tecnología, No. 8, junio 2011 pp.93-106
Plant Species Diversity and Composition of Plant Communities in Buffer Zones with Variable Management Regimes
Authors: Tarmi Sanna , Hyvönen Terho
Published: July 2012

Field boundaries with permanent vegetation cover are a key habitat for farmland biodiversity. Buffer zones are wide field boundaries established to prevent nutrient leaching and erosion into waterways and serve as habitats for farmland wildlife. Our main hypothesis was that several years of grazing or cutting management results in greater plant species richness and heterogeneity in buffer zones in comparison with sites managed for only a few years. We also hypothesized that litter cover and soil phosphorus (P) level would decrease after several years of management, in comparison sites with relatively few years of management. Through this study we aimed to gain a better understanding of how to increase biodiversity in buffer zones. The study included 15 buffer zones within a single landscape. Mean species richness was significantly higher in the group of sites grazed over several years (21 species) in contrast to extensively cut sites (14.8 species) and/or grazed sites (18 species). Species heterogeneity did not respond to different management regimes. Management, slope aspect and litter were significant explanatory factors for species composition. The amount of soil phosphorus measured at three different depths was significantly lower in the buffer zones managed by cutting or grazing for a few years in contrast to those that were grazed for several years. Management that positively affected species diversity did not result in the expected decrease in soil phosphorus. Therefore, we propose that the greater species richness at grazed sites results mainly from disturbances caused by grazing.
L'engagement académique de l'étudiant comme facteur de réussite à l'université Étude exploratoire menée dans deux facultés contrastées
Authors: Pirot Laurence , De Ketele Jean-Marie
Published: July 2012

Cet article explore l'impact de l'engagement scolaire sur la réussite d'étudiants universitaires de première année inscrits dans les filières de psychologie et de polytechnique. Une revue critique de la documentation scientifique conduit les auteurs à postuler que le niveau de réussite est davantage déterminé par ses aspects qualitatifs que quantitatifs. L'analyse de données recueillies par interview et questionnaire auprès de 38 sujets révèle des indicateurs significatifs d'engagement, des liens entre ces indicateurs et la réussite; elle permet d'observer les effets intermédiaires de l'orientation d'étude, du capital socioculturel et du vécu de l'étudiant. Pour les deux filières, l'approche d'apprentissage guidée par un souci de compréhension globaliste semble la plus associée à un haut niveau de réussite. La gestion du temps et certains comportements stratégiques d'organisation déterminent aussi la bonne adaptation aux exigences universitaires.
L'(in)satisfaction au travail des professeurs du second degré du Sénégal
Authors: Ndoye Abdou Karim
Published: July 2012

Le présent article porte sur la satisfaction au travail des enseignants d'un pays de l'Afrique subsaharienne. Plus précisément, l'auteur étudie l'insatisfaction au travail des professeurs de l'enseignement moyen et secondaire du Sénégal (Afrique de l'Ouest). Il reprend, en l'approfondissant, une investigation menée dans ce pays sur la satisfaction au travail des enseignants. Pour ce faire, il expose d'abord, sous forme d'un graphique, la fréquence des notes attribuées par les «enquêtés» à chacun des facteurs de leur condition enseignante pour lesquels ils ressentent de la satisfaction ou de l'(in)satisfaction. Ces facteurs seront présentés en partant de ceux qui ont les plus faibles scores de satisfaction générale vers ceux qui ont les plus forts.