bluuebunny/crossref_metadata_2025 huggingface dataset:
Indications of nitrogen-limited methane uptake in tropical forest soils
Authors: Veldkamp E. , Koehler B. , Corre M. D.
Published: August 2013

Abstract. It is estimated that tropical forest soils contribute 6.2 Tg yr−1 (28%) to global methane (CH4) uptake, which is large enough to alter CH4 accumulation in the atmosphere if significant changes would occur to this sink. Elevated deposition of inorganic nitrogen (N) to temperate forest ecosystems has been shown to reduce CH4 uptake in forest soils, but almost no information exists from tropical forest soils even though projections show that N deposition will increase substantially in tropical regions. Here we report the results from two long-term, ecosystem-scale experiments in which we assessed the impact of chronic N addition on soil CH4 fluxes from two old-growth forests in Panama: (1) a lowland, moist (2.7 m yr−1 rainfall) forest on clayey Cambisol and Nitisol soils with controls and N-addition plots for 9–12 yr, and (2) a montane, wet (5.5 m yr−1 rainfall) forest on a sandy loam Andosol soil with controls and N-addition plots for 1–4 yr. We measured soil CH4 fluxes for 4 yr (2006–2009) in four replicate plots (40 m × 40 m each) per treatment using vented static chambers (four chambers per plot). CH4 fluxes from the lowland control plots and the montane control plots did not differ from their respective N-addition plots. In the lowland forest, chronic N addition did not lead to inhibition of CH4 uptake; instead, a negative correlation of CH4 fluxes with nitrate (NO3–) concentrations in the mineral soil suggests that increased NO3– levels in N-addition plots had stimulated CH4 consumption and/or reduced CH4 production. In the montane forest, chronic N addition also showed negative correlation of CH4 fluxes with ammonium concentrations in the organic layer, which suggests that CH4 consumption was N limited. We propose the following reasons why such N-stimulated CH4 consumption did not lead to statistically significant CH4 uptake: (1) for the lowland forest, this was caused by limitation of CH4 diffusion from the atmosphere into the clayey soils, particularly during the wet season, as indicated by the strong positive correlations between CH4 fluxes and water-filled pore space (WFPS); (2) for the montane forest, this was caused by the high WFPS in the mineral soil throughout the year, which may not only limit CH4 diffusion from the atmosphere into the soil but also favour CH4 production; and (3) both forest soils showed large spatial and temporal variations of CH4 fluxes. We conclude that in these extremely different tropical forest ecosystems there were indications of N limitation on CH4 uptake. Based on these findings, it is unlikely that elevated N deposition on tropical forest soils will lead to a rapid reduction of CH4 uptake.
Removal and transformation of pharmaceuticals in wastewater treatment plants and constructed wetlands
Authors: Lee E. , Lee S. , Park J. , Kim Y. , Cho J.
Published: August 2013

Abstract. Since trace organic compounds such as pharmaceuticals in surface water have been a relevant threat to drinking water supplies, in this study removal of pharmaceuticals and transformation of pharmaceuticals into metabolites were investigated in the main source of micropollutants such as WWTPs and engineered constructed wetlands. Pharmaceuticals were effectively removed by different WWTP processes and wetlands. Pharmaceutical metabolites with relatively low log D value were resulted in the low removal efficiencies compared to parent compounds with relatively high log D value, indicating the stability of metabolites. And the constructed wetlands fed with wastewater effluent were encouraged to prevent direct release of micropollutants into surface waters. Among various pharmaceuticals, different transformation pattern of ibuprofen was observed with significant formation of 1-hydroxy-ibuprofen during biological treatment in WWTP, indicating preferential biotransformation of ibuprofen. Lastly, transformation of pharmaceuticals depending on their structural position was investigated in terms of electron density, and, the electron rich C1 = C2 bond of carbamazepine was revealed as an initial transformation position.
An interaction network perspective on the relation between patterns of sea surface temperature variability and global mean surface temperature
Authors: Tantet A. , Dijkstra H. A.
Published: August 2013

Abstract. On interannual-to-multidecadal time scales variability in sea surface temperature appears to be organized in large-scale spatiotemporal patterns. In this paper, we investigate these patterns by studying the community structure of interaction networks constructed from sea surface temperature observations. Much of the community structure as well as the first neighbour maps can be interpreted using known dominant patterns of variability, such as the El Niño/Southern Oscillation and the Atlantic Multidecadal Oscillation and teleconnections. The community detection method allows to overcome some shortcomings of Empirical Orthogonal Function analysis or composite analysis and hence provides additional information with respect to these classical analysis tools. The community analysis provides also new insight into the relationship between patterns of sea surface temperature and the global mean surface temperature (GMST). On the decadal-to-multidecadal time scale, we show that only two communities (Indian Ocean and North Atlantic) determine most of the GMST variability.
PEATBOG: a biogeochemical model for analyzing coupled carbon and nitrogen dynamics in northern peatlands
Authors: Wu Y. , Blodau C.
Published: August 2013

Abstract. Elevated nitrogen deposition and climate change alter the vegetation communities and carbon (C) and nitrogen (N) cycling in peatlands. To address this issue we developed a new process-oriented biogeochemical model (PEATBOG) for analyzing coupled carbon and nitrogen dynamics in northern peatlands. The model consists of four submodels, which simulate: (1) daily water table depth and depth profiles of soil moisture, temperature and oxygen levels; (2) competition among three plants functional types (PFTs), production and litter production of plants; (3) decomposition of peat; and (4) production, consumption, diffusion and export of dissolved C and N species in soil water. The model is novel in the integration of the C and N cycles, the explicit spatial resolution belowground, the consistent conceptualization of movement of water and solutes, the incorporation of stoichiometric controls on elemental fluxes and a consistent conceptualization of C and N reactivity in vegetation and soil organic matter. The model was evaluated for the Mer Bleue Bog, near Ottawa, Ontario, with regards to simulation of soil moisture and temperature and the most important processes in the C and N cycles. Model sensitivity was tested for nitrogen input, precipitation, and temperature, and the choices of the most uncertain parameters were justified. A simulation of nitrogen deposition over 40 yr demonstrates the advantages of the PEATBOG model in tracking biogeochemical effects and vegetation change in the ecosystem.
Aircraft routing with minimal climate impact: the REACT4C climate cost function modelling approach (V1.0)
Authors: Grewe V. , Frömming C. , Matthes S. , Brinkop S. , Ponater M. , Dietmüller S. , Jöckel P. , Garny H. , Tsati E. , Søvde O. A. , Fuglestvedt J. , Berntsen T. K. , Shine K. P. , Irvine E. A. , Champougny T. , Hullah P.
Published: August 2013

Abstract. In addition to CO2, the climate impact of aviation is strongly influenced by non-CO2 emissions, such as nitrogen oxides, influencing ozone and methane, and water vapour, forming contrails. Because these non-CO2 emission effects are characterised by a short lifetime, their climate impact largely depends on emission location and time, i.e. emissions in certain locations (or times) can lead to a greater climate impact (even on the global average) than the same emission in other locations (or times). Avoiding these climate sensitive regions might thus be beneficial to climate. Here, we describe a modelling chain for investigating this climate impact mitigation option. It forms a multi-step modelling approach, starting with the simulation of the fate of emissions released at a certain location and time (time-region). This is performed with the chemistry–climate model EMAC, extended by the two submodels AIRTRAC 1.0 and CONTRAIL 1.0, which describe the contribution of emissions to the composition of the atmosphere and the contrail formation. Numerous time-regions are efficiently calculated by applying a Lagrangian scheme. EMAC also includes the calculation of radiative impacts, which are, in a second step, the input to climate metric formulas describing the climate impact of the time-region emission. The result of the modelling chain comprises a four dimensional dataset in space and time, which we call climate cost functions, and which describe at each grid point and each point in time, the climate impact of an emission. In a third step, these climate cost functions are used in a traffic simulator (SAAM), coupled to an emission tool (AEM) to optimise aircraft trajectories for the North Atlantic region. Here, we describe the details of this new modelling approach and show some example results. A number of sensitivity analyses are performed to motivate the settings of individual parameters. A stepwise sanity check of the results of the modelling chain is undertaken to demonstrate the plausibility of the climate cost functions.
"Last mile" challenges to in situ volcanic data transmission
Authors: Fonseca J. F. B. D. , Faria B. V. E. , Trindade J. , Cruz G. , Chambel A. , Silva F. M. , Pereira R. L. , Vazão T.
Published: August 2013

Abstract. Scientists play a key role in volcanic risk mitigation, but rely heavily on fast access to data acquired in the vicinity of an active volcano. Hazardous volcanoes are often located in remote areas were telecommunications infrastructure is fragile. Besides being exposed directly to the volcanic hazard, the infrastructure in such remote areas can suffer also from "last mile" limitations derived from lack of market demand for data transmission services. In this paper, we report on the findings of FP7 MIAVITA project in the topic of volcanic data transmission. We draw on the contribution of partners from emergent or developing countries to identify the main bottlenecks and fragilities. We present also the results of an experiment conducted in Fogo island, Cape Verde, to test the availability of VSAT services adequate for volcanic monitoring. We warn against the false sense of security resulting from increasingly ubiquitous connectivity, and point out the lack of reliability of many consumer-type services, particularly during emergencies when such services are likely to crash due to excess of demand from the public. Finally, we propose guidelines and recommend best practices for the design of volcanic monitoring networks in what concerns data transmission. In particular, we advise that the data transmission equipment close to the exposed area should be owned, operated and maintained by the volcanic monitoring institution. We exemplify with the setup of the Fogo telemetric interface, which uses low-power licence-free radio modems to reach a robust point of entry into the public network at a suitable distance from the volcano.
Snowdrift modelling for the Vestfonna ice cap, north-eastern Svalbard
Authors: Sauter T. , Möller M. , Finkelnburg R. , Grabiec M. , Scherer D. , Schneider C.
Published: August 2013

Abstract. The redistribution of snow by drifting and blowing snow frequently leads to an inhomogeneous snow mass distribution on larger ice caps. Together with the thermodynamic impact of drifting snow sublimation on the lower atmospheric boundary layer, these processes affect the glacier surface mass balance. This study provides a first quantification of snowdrift and sublimation of blowing and drifting snow on the Vestfonna ice cap (Svalbard) by using the specifically designed snow2blow snowdrift model. The model is forced by atmospheric fields from the Polar Weather Research and Forecasting model and resolves processes on a spatial resolution of 250 m. The model is applied to the Vestfonna ice cap for the accumulation period 2008/2009. Comparison with radio-echo soundings and snow-pit measurements show that important local-scale processes are resolved by the model and the overall snow accumulation pattern is reproduced. The findings indicate that there is a significant redistribution of snow mass from the interior of the ice cap to the surrounding areas and ice slopes. Drifting snow sublimation of suspended snow is found to be stronger during spring. It is concluded that the redistribution process is strong enough to have a significant impact on glacier mass balance.
DISCOVERY AND DEVELOPMENT OF A NEW SYNTHETIC RUBBER: HIGH TRANS SBR
Authors: Livigni Russell A.
Published: August 2013

The discovery and development of high trans styrene–butadiene rubber (SBR) is presented. High trans SBR is prepared using a novel polymerization initiator of a specific combination of a barium salt and organometallic compound in a hydrocarbon solvent. The trans-1,4 content of the polybutadiene repeat units is sufficiently high, at a low vinyl content, to result in a crystallizing rubber. As a result, high trans SBR has high green strength similar to natural rubber (NR). The barium-based initiating system allows the formation of copolymers between butadiene and styrene, in which the distribution of styrene repeat units is considerably more random than that obtained with an organolithium initiator alone. By a judicious selection of the two initiator composition and the styrene content in the copolymer, high trans SBR also exhibits good building tack, again similar to NR. The properties of high green strength and good building tack for high trans SBR are unique among common synthetic rubbers. As such, high trans SBR is an excellent candidate for use as a tire carcass rubber in radial ply tire construction. High trans SBR is also valuable in tire tread compositions, providing good abrasion resistance.
Visual Impairment and Spectacle Use in Schoolchildren in Rural and Urban Regions in Beijing
Authors: Guo Yin , Liu Li Juan , Xu Liang , Lv Yan Yun , Tang Ping , Feng Yi , Meng Meng , Jonas Jost B.
Published: August 2013

Purpose:

To determine prevalence and associations of visual impairment and frequency of spectacle use among grade 1 and grade 4 students in Beijing.

Methods:

This school-based, cross-sectional study included 382 grade 1 children (age 6.3 ± 0.5 years) and 299 grade 4 children (age 9.4 ± 0.7 years) who underwent a comprehensive eye examination including visual acuity, noncycloplegic refractometry, and ocular biometry.

Results:

Presenting visual acuity (mean 0.04 ± 0.17 logMAR) was associated with younger age (p = 0.002), hyperopic refractive error (p<0.001), and male sex (p = 0.03). Presenting visual impairment (presenting visual acuity ≤20/40 in the better eye) was found in 44 children (prevalence 6.64 ± 1.0% [95% confidence interval (CI) 4.74, 8.54]). Mean best-corrected visual acuity (right eyes –0.02 ± 0.04 logMAR) was associated with more hyperopic refractive error (p = 0.03) and rural region of habitation (p<0.001). The prevalence of best-corrected visual impairment (best-corrected visual acuity ≤20/40 in the better eye) was 2/652 (0.30 ± 0.21% [95% CI 0.00, 0.72]). Undercorrection of refractive error was present in 53 children (7.99 ± 1.05%) and was associated with older age (p = 0.003; B 0.53; OR 1.71 [95% CI 1.20, 2.42]), myopic refractive error (p = 0.001; B –0.72; OR 0.49 [95% CI 0.35, 0.68]), and longer axial length (p = 0.002; B 0.74; OR 2.10 [95% CI 1.32, 3.32]). Spectacle use was reported for 54 children (8.14 ± 1.06%). Mean refractive error of the worse eyes of these children was –2.09 ± 2.88 D (range –7.38 to +7.25 D).

Conclusions:

Factors associated with presenting visual impairment were older age, myopic refractive error, and higher maternal education level. Despite a prevalence of myopia of 33% in young schoolchildren in Greater Beijing, prevalence of best-corrected visual impairment (0.30% ± 0.21%), presenting visual impairment (6.64% ± 1.0%), and undercorrection of refractive error (7.99% ± 1.05%) were relatively low.
Monthly Intravitreal Bevacizumab for Macular Edema after Iodine-125 Plaque Radiotherapy of Uveal Melanoma
Authors: Mashayekhi Arman , Rojanaporn Duangnate , Al-Dahmash Saad , Shields Carol L. , Shields Jerry A.
Published: August 2013

Purpose:

To examine the efficacy of monthly injections of intravitreal bevacizumab (IVB) for macular edema after iodine-125 plaque radiotherapy of uveal melanoma.

Methods:

We studied 36 patients with macular edema after plaque radiotherapy of uveal melanoma in this noncomparative, interventional case series. All eyes were treated with 4 monthly injections of IVB. Central macular thickness (CMT) and best-corrected visual acuity (BCVA) were measured before each injection and 4-6 months after the first injection. The main outcome measures were change in CMT and BCVA.

Results:

At 4-6 months following the first IVB, 20 eyes (56%) had decreased CMT, 11 eyes (31%) had stable CMT, and 5 eyes (14%) had increased CMT. The mean change in CMT and the mean percent change in CMT at 4-6 months compared to baseline were –91 μm (–20%) in all eyes, –174 μm (–37%) in the group with decreased macular thickness, –14 μm (–3%) in the group with stable macular thickness, and +69 μm (+17%) in the group with increased macular thickness. At 4-6 months, 15 eyes (42%) had increased BCVA, 16 eyes (44%) had stable BCVA, and 5 eyes (14%) had decreased BCVA. An increase in CMT was seen between the fourth monthly IVB injection and the final evaluation at 4-6 months after the first injection in all 3 groups of our study.

Conclusions:

At 4-6 months following the first injection, 4 monthly injections of IVB in eyes with macular edema after plaque radiotherapy of uveal melanoma decreased macular edema in 56% and improved BCVA in 42% of the treated eyes.
Magnetoencephalography: Fundamentals and Established and Emerging Clinical Applications in Radiology
Authors: Braeutigam Sven
Published: August 2013

Magnetoencephalography is a noninvasive, fast, and patient friendly technique for recording brain activity. It is increasingly available and is regarded as one of the most modern imaging tools available to radiologists. The dominant clinical use of this technology currently centers on two, partly overlapping areas, namely, localizing the regions from which epileptic seizures originate, and identifying regions of normal brain function in patients preparing to undergo brain surgery. As a consequence, many radiologists may not yet be familiar with this technique. This review provides an introduction to magnetoencephalography, discusses relevant analytical techniques, and presents recent developments in established and emerging clinical applications such as pervasive developmental disorders. Although the role of magnetoencephalography in diagnosis, prognosis, and patient treatment is still limited, it is argued that this technology is exquisitely capable of contributing indispensable information about brain dynamics not easily obtained with other modalities. This, it is believed, will make this technology an important clinical tool for a wide range of disorders in the future.
Characterization of anIn VitroModel of Extracorporeal Circulation: A New Tool for Investigating the Pathophysiological and Therapeutic Strategies in Whole Blood
Authors: Matata Bashir M. , Elahi Maqsood M.
Published: August 2013

A clinically relevant extracorporeal circulation model would be a valuable tool for investigating the pathophysiological and therapeutic strategies in whole blood. Previous models were limited by issues such as large circuit area; the inability to achieve full bypass; and donor blood requirement for prime. Here we established a miniature circuit to overcome these limitations consisting of a peristaltic pump, a test cell, a blood reservoir, and an oxygenator connected via polyvinylchloride and porous platinum silicon tubing. A heparinised (10 U/mL) saline solution at pH 7.4 was used to prime the circuit and the test cell was incubated in a water bath to maintain the temperature at 37°C. Blood flow through the circuit was at 5 mL/minute rate. Haemodynamics, haemoglobin concentration, and blood gases were analysed and the circuit performance was optimised according to the levels of haemolysis at three circulation time intervals: before the start, 30 minutes, and 60 minutes. No statistically significant haemodynamics and blood gases differences were observed. We have established a miniature extracorporeal circuit consisting of asanguineous prime for CPB model that maintains clinically acceptable results regarding hemodynamic parameters, blood gases, and haemodilution. This surrogate model would be important for further use in clinically pertinent research.
Market Design with Centralized Wind Power Management: Handling Low-predictability in Intraday Markets
Authors: Henriot Arthur
Published: August 2013

This paper evaluates the benefits for an agent managing the wind power production within a given power system to trade in the intraday electricity markets, in a context of massive penetration of intermittent renewables. Using a simple analytical model we find out that there are situations when it will be costly for this agent to adjust its positions in intraday markets. A first key factor is of course the technical flexibility of the power system: if highly flexible units provide energy at very low prices in real-time there is no point in participating into intraday markets. Besides, we identify the way wind production forecast errors evolve constitutes another essential, although less obvious, key-factor. Both the value of the standard error and the correlation between forecasts errors at different gate closures will determine the strategy of the wind power manager. Policy implications of our results are the following: low liquidity in intraday markets will be unavoidable for given sets of technical parameters, it will also be inefficient in some cases to set discrete auctions in intraday markets, and compelling players to adjust their position in intraday markets will then generate additional costs.
Kompetence k učení a možnosti jejího rozvíjení a hodnocení: vymezení pojmu a přehled současných přístupů
Authors: Lokajíčková V.
Published: August 2013

Přehledová studie zpřístupňuje poznatky o kompetenci k učení a možnostech jejího rozvíjení ve výuce. Studie je rozvržena do dvou částí. První část se zabývá vymezením kompetence k učení v návaznosti na koncept (klíčových) kompetencí. S oporou o vybrané autory je kompetence k učení strukturována do dílčích dimenzí – (sub)dimenzí a je tak upozorněno na problém jejího pojetí jako multidimenzionálního konstruktu. Dále je poukázáno na zařazení jednotlivých dimenzí a (sub)dimenzí u vybraných autorů, což přináší další komplikace spojené s tímto konstruktem. U autorů jsou identifikovány tři přístupy k vymezení kompetence k učení prostřednictvím: (1) kvalit – charakteristik, (2) komponent – složek a (3) propojením kvalit a komponent (kombinovaný přístup). V druhé části studie jsou představeny čtyři domácí přístupy umožňující rozvíjet kompetenci k učení ve výuce. První dva představené přístupy (Výzkumného ústavu pedagogického) nahlíží na kompetenci k učení prostřednictvím „širší“ perspektivy (makroměřítko). Další dva přístupy (Chvála a Kasíkové a Institutu výzkumu školního vzdělávání) nahlíží na kompetenci k učení více zaostřeně (mikroměřítko) a umožňují i její hodnocení.
Current Management of Obesity in an Infertile Female-Recent Advances and Future Prospective Drugs
Authors: Kulvinder Kochar Kaur  , Gautam Allahbadia  , Mandeep Singh
Published: August 2013

With obesity having grown to epidemic proportions, nearly half of women of reproductive age are overweight and obese and this is a major public health problem. Due to unfavourable ovarian stimulation protocols, higher gonadotropin consumption and poor results most insurance companies are reluctant to sponsor treatment for such patients .Since diet and exercise are inadequate treatments and bariatric surgery maybe too extreme, treatment in the model of other chronic diseases by combination therapies has prompted the development of novel combination therapies like Qysmia (topiramate/phentermine)/Contrave (Bupropion SR/Naltrexone SR) which simultaneously target multiple physiological pathways that regulate energy homeostasis to overwhelm endogenous compensatory mechanisms as opposed touse of monotherapies to maintain weight loss. The only concern is the slight risk of teratogenicity with topiramate hence it is better to use contraception while using topiramate/bupropionSR/naltrexoneSR. In obese diabetics the GLP-1 receptor agonists like exenatide/liraglutide remain the drugs of choice incombination with insulin, while combination of lixisenatide and insulinglargine are in the pipeline for the future.
Evaluation of Ovulation Inhibition Properties of a Phytoestrogen Isolated from Momordica charantia Linn. Seeds
Authors: Patil Sharanabasappa A.
Published: August 2013

Background and objectives: Momordica charantia Linn. has been used as a dietary / medicinal supplement for health care. The plant has a long history in worldwide people for the usage of vaginal discharge, to promote menstruation and to induce abortions. However, the mechanism of action for its ovulation inhibition effects is not clearly known. Therefore, the present study was carried out to evaluate the ovulation inhibition properties of phytoestrogenic molecule isolated from M. charantia seeds in albino rats as an experimental model.
Methods: Ovulation inhibition properties of fractions of ethanol extract and phenolphthalein a phytoestrogenic molecule isolated from seeds of Momordica charantia Linn. were evaluated in fertile female albino rats. In the first batch of animals having groups I, II, III, IV were treated with 15 and 25mg/100g oral doses of Fraction I and Fraction II and group V served as control. In the second batch of animals having groups I, II, III was treated with 10, 15 & 20mg/100g isolated phenolphthalein and group IV served as control.
Results: At autopsy on day 31st, decrease in ovarian weight and histological studies shows highly significant decrease in number of developing follicles, Graafian follicles, corpora lutea and significant increased in number of atreatic follicles is observed in Fraction I and phenolphthalein treatment. There are no appreciable changes are observed in the above parameters when both the doses of Fraction II administration.
Interpretation and Conclusions: The study results suggested that M. charantia seed fractions and phenolphthalein possess ovulation inhibition properties in experimental animals. Interestingly, in recent years, the popularity of different kinds of pharmaceutical preparations containing phytoestrogens has constantly increasing. Therefore, studies of the influence of the above mentioned plant components on female reproduction have become more and more important. This leads to discovery of newer phytoconstituents with better activities and provide source of new biomolecules for biologists to work on. The studies explore the utilization of medicinal plants for effective management of contraception. It gives a larger platform for the medicinal plant growers by providing scientific support and data to the traditional invalidated herbal drugs. Taking account of all these facts, the present study was undertaken in albino rats.
Diagnostic Testing of Primary Vitreo-Retinal Lymphoma
Authors: A. Bajwa  , C. Stephen Foster
Published: August 2013

Primary Vitreo-Retinal Lymphoma (PVRL) or Primary Intra-Ocular Lymphoma (PIOL) is a rare malignancy often seen as a context of primary central nervous system lymphoma (PCNSL). This article reviews the diagnostic approach of PVRL. The techniques for diagnosing PVRL from ocular biopsy specimens includes cytologic analysis, immuno-cytochemistry, flow-cytometry, polymerase chain reaction (PCR) to detect V-J Ig gene re-arrangements, and analysis of IL6, IL10 in aqueous or vitreous fluid. Currently, cytology in combination with immunohistochemistry is considered the gold standard for the diagnosis of PVRL. But ancillary tests including IgH, TCR gene rearrangements and cytokine analysis are reliable biomarkers for B and T cell PVRL. Genetic testing with t(14:18) detection may show promising results in future.
Le profil et le cheminement scolaire des jeunes québécois issus de l’immigration au secondaire : un portrait statistique
Authors: Mc Andrew Marie , Ledent Jacques , Murdoch Jake , Ait-Said Rachid , Balde Alhassane
Published: August 2013

Cet article présente un portrait du cheminement scolaire des élèves québécois issus de l’immigration qui ont commencé leur secondaire dans le secteur francophone en 1998 ou 1999. Les résultats de ce groupe-cible, constitué des élèves nés à l’étranger ou dont au moins un parent est né à l’étranger, sont comparés à ceux d’un groupe-contrôle d’élèves dont les deux parents sont nés au Canada. Dans un premier temps, nous dressons un profil du groupe-cible, de ses sous-groupes ainsi que du groupe-contrôle à partir de 11 variables regroupées en trois grandes catégories : les données sociodémographiques, les variables liées au processus de scolarisation et les caractéristiques des écoles fréquentées. Dans un second temps, le cheminement scolaire est analysé grâce à 5 indicateurs : le retard scolaire accumulé deux ans après l’entrée en secondaire, le taux d’obtention d’un diplôme secondaire selon divers horizons temporels, le taux cumulatif d’obtention d’un diplôme secondaire dans les réseaux public et privé, le secteur d’obtention du diplôme et l’estimation des taux de décrochage net.
La reconstruction des dynamiques démographiques locales en Algérie (1987-2008) par des techniques d’estimation indirecte
Authors: Kouaouci Ali , Rabah Saadi
Published: August 2013

L’Algérie a connu une décennie noire, de 1991 à 2000, marquée par la violence politique, qui aurait causé environ 200 000 morts, a fait reculer les mariages et les naissances et a occasionné de grands mouvements de population. La violence a considérablement diminué depuis les années 2000 et le présent document tente d’évaluer la façon dont la fécondité, la mortalité et la migration ont pu changer au cours de la période de violence et après le retour d’une paix relative. Se peut-il que les techniques indirectes utilisées au niveau régional clarifient la question ? L’Algérie a effectué trois recensements généraux de la population et de l’habitat (1987, 1998 et 2008) en adoptant la même division en 48 wilayates (provinces). Nous allons utiliser ces 3 recensements, ainsi que les données d’état civil et l’enquête MICS de 2006. La technique indirecte ADJASFR a été très utile et a fourni des estimations de l’indice synthétique de fécondité très proches de l’indice direct tiré du recensement de 1998. La migration forcée explique, en partie, les changements observés dans la fécondité et la mortalité.
De l’interprétation des indicateurs linguistiques du recensement canadien
Authors: Bélanger Alain , Sabourin Patrick
Published: August 2013

Au Canada, les comportements et les caractéristiques linguistiques des individus sont documentés au moyen d’une grande diversité de questions d’enquête et de recensement. Paradoxalement, cette abondance unique au monde soulève des questionnements méthodologiques importants. En effet, quel indicateur privilégier pour effectuer un suivi de la situation linguistique ? Est-il légitime de s’intéresser à l’évolution de la langue parlée à la maison, qui relève de sphère privée ? Comment comparer entre eux les divers indicateurs linguistiques ? Dans cette note de recherche, les auteurs tentent de montrer que chacun des indicateurs linguistiques dépeint une facette particulière de la question linguistique. La langue étant un phénomène social complexe et multifactoriel, aucun indicateur unique ne saurait décrire à lui seul l’évolution de la situation linguistique. Une méthode permettant de comparer les indicateurs de langue maternelle, de langue d’usage privé (langue parlée à la maison) et de langue d’usage public (langue de travail) est également proposée. Les résultats montrent que l’immigration a un impact négatif sur le poids du français et que, contrairement à ce qui a été affirmé de nombreuses fois par le passé, c’est la langue d’usage public, et non la langue d’usage privé, qui est la plus affectée.
Perspectives de pères d’un enfant alimenté autrement dans une société valorisant l’allaitement maternel1
Authors: de Montigny Francine , Lacharité Carl , Devault Annie , St-Arneault Kate , Girard Marie-Ève , Vachon Éric , Gervais Christine
Published: August 2013

L’allaitement maternel est promu par les organismes de santé publique tant québécois qu’internationaux, qui le considèrent comme le meilleur mode d’alimentation pour l’enfant. Cependant, un peu plus d’un couple québécois sur quatre choisit une autre option d’alimentation. Cette étude vise à décrire et à comprendre l’expérience des pères dont l’enfant n’a pas été allaité ou a été sevré de façon précoce. Vingt-huit pères décrivent trois trajectoires de décision et les effets de l’alimentation artificielle sur leur rôle, la vie familiale et le soutien professionnel reçu. Les pères ressentent en effet une pression sociale d’alimenter l’enfant au sein, notamment de la part des professionnels de la santé.
Dépister la violence conjugale en médiation familiale
Authors: Riendeau Louise
Published: August 2013

Le dépistage de la violence conjugale chez les couples qui font appel à la médiation familiale constitue une étape essentielle pour assurer la sécurité des victimes. De 2009 à 2011, un projet pilote a permis de former 330 médiatrices et médiateurs afin qu’ils puissent identifier les signes de violence conjugale et adopter une pratique sécuritaire. Si le projet de formation a permis des avancées sur le plan de la connaissance et del’utilisation des outils de dépistage, plusieurs continuent tout de même le processus de médiation, malgré la présence de violence. L’expérience démontre que si la formation est à poursuivre, un cadre législatif et normatif doit appuyer ces efforts.
Redox Reactions in Prussian Blue Analogue Films with Fast Na+ Intercalation
Authors: Takachi Masamitsu , Matsuda Tomoyuki , Moritomo Yutaka
Published: August 2013

Electronic state of cobalt and manganese Prussian blue analogues were systematically investigated against Na+ intercalation by means of the infrared and X-ray absorption spectroscopies. The spectroscopies revealed that 3.8 and 3.4 V plateaus in the discharge curve of Na
x
Co[Fe(CN)6]0.902.9H2O (denoted as NCF90) are ascribed to the reduction processes of Fe3+ and Co3+, respectively. On the other hand, 3.6 and 3.2 V plateaus of Na
x
Mn[Fe(CN)6]0.833.5H2O (NMF83) are ascribed to the reduction processes of Mn3+ and Fe3+, respectively. We found that the film electrodes with a thickness of 1.1 µm exhibit fast Na+ intercalations: the discharge capacity at 60 C of the NCF90 (NFM83) film was 90% (45%) of the open-circuit-voltage (OCV) value. Thus, Prussian blue analogue films are promising cathode candidates for sodium-ion secondary batteries.
Observation of Leader Development in Rod–Rod Air Gaps under Negative Switching Impulse
Authors: Xie Yaoheng , He Hengxin , He Junjia
Published: August 2013

The leader development in rod–rod gap under negative switching impulse was investigated by using two high-speed cameras. The clearer and more particular colorized physical morphology of the streamer-leader system than the traditional image converter cameras were recorded. On the basis of high time resolution images, the leader development parameters such as negative leader step length, final jump length and positive upward leader velocity and so on for rod–rod configuration are reported in the paper.
Measurement of Ionization Energies of Nitrogen in 4H-SiC by Traveling-Wave Method
Authors: Takase Tsuyoshi , Sakaino Masamichi , Sun Yong , Miyasato Tatsuro
Published: August 2013

The impurity bands and corresponding ionization energies of nitrogen atoms in a 4H-SiC crystal with a concentration of 1×1019 cm-3 are measured by a nondestructive and noncontact traveling-wave method. When a SiC sample was placed near the surface of a surface acoustic wave device, its conductivity can be obtained by measuring the attenuation of the piezo-potential traveling-wave grazing along the surface of the sample. Temperature-dependent conductivities corresponding to a freeze-out process of free carriers excited from nitrogen atoms were observed, and the corresponding ionization energies of the nitrogen atoms were estimated by the Arrhenius plot method. The ionization energies in the impurity bands originating from splits of the doping atoms at cubic and hexagonal sites in the carbon sublattice are 72.89 and 47.89 meV, respectively, at room temperature. The ionization energies are in good agreement with the results reported in other theoretical and experimental studies. We also found that the skin depth of the traveling wave in the sample is below 1 mm and that the mobility of the carriers is strongly affected by both ionized dopants and charged surface defects in the depletion region near the surface of the sample. The effects of the sample and traveling wave such as the polarization effects of the crystal and the frequency effects of the traveling wave are discussed.
Improved High-Frequency Performance of Microstrip-Line-Type Liquid Crystal Phase Shifter
Authors: Nose Toshiaki , Chien Liang-Chy , Catanescu Otilia , Golvin Andrii , Ito Yusuke , Sasamori Takayuki , Isota Yoji , Ito Ryouta , Honma Michinori
Published: August 2013

A novel microstrip-line (MSL)-type liquid crystal (LC) phase shifter is designed to retain both the ease of fabrication with a coplanar waveguide (CPW)-type LC phase shifter and the excellent phase-shifting properties of the MSL-type one. The converting circuit, which is a key component of the device, is optimized so as to improve the operating frequency. Then, the phase-shifting properties and loss phenomena are investigated by using various LC materials. The operational frequency is extremely improved by employing a novel large birefringence LC material and the optimized design.
Effect of the Surface Affinity of Liquid Crystals and Monomers on the Orientation of Polymer-Dispersed Liquid Crystal
Authors: Lee Ji-Hoon , Yoon Tae-Hoon
Published: August 2013

We investigated the effect of the surface affinity of liquid crystals and reactive monomers on liquid crystal orientation. Liquid crystals and monomers having different contact angles with the vertical alignment polyimide were mixed and photo-polymerized using a UV light. Liquid crystals with smaller contact angles and reactive monomers with greater contact angles promoted a uniform vertical orientation of liquid crystals with a vertical polymer morphology. On the other hand, liquid crystals with greater contact angles and monomers with smaller contact angles resulted in a deformed liquid crystal orientation with an elliptical polymer structure.
Just Roll with It? Rolling Volumes vs. Discrete Issues in Open Access Library and Information Science Journals
Authors: Cirasella Jill , Bowdoin Sally
Published: August 2013

INTRODUCTION Articles in open access (OA) journals can be published on a rolling basis, as they become ready, or in complete, discrete issues. This study examines the prevalence of and reasons for rolling volumes vs. discrete issues among scholarly OA library and information science (LIS) journals based in the United States. METHODS A survey was distributed to journal editors, asking them about their publication model and their reasons for and satisfaction with that model. RESULTS Of the 21 responding journals, 12 publish in discrete issues, eight publish in rolling volumes, and one publishes in rolling volumes with an occasional special issue. Almost all editors, regardless of model, cited ease of workflow as a justification for their chosen publication model, suggesting that there is no single best workflow for all journals. However, while all rolling-volume editors reported being satisfied with their model, satisfaction was less universal among discrete-issue editors. DISCUSSION The unexpectedly high number of rolling-volume journals suggests that LIS journal editors are making forward-looking choices about publication models even though the topic has not been much addressed in the library literature. Further research is warranted; possibilities include expanding the study’s geographic scope, broadening the study to other disciplines, and investigating publication model trends across the entire scholarly OA universe. CONCLUSION Both because satisfaction is high among editors of rolling-volume journals and because readers and authors appreciate quick publication times, the rolling-volume model will likely become even more prevalent in coming years.
Comparative Study of Nano‐ZSM‐5 Catalysts Synthesized in OH− and F− Media
Authors: Qin Zhengxing , Lakiss Louwanda , Tosheva Lubomira , Gilson Jean‐Pierre , Vicente Aurélie , Fernandez Christian , Valtchev Valentin
Published: August 2013

This study reports the seeded synthesis of MFI‐type (ZSM‐5) zeolite in fluoride medium at pH = 8.5. Crystal growth kinetics of the resulting zeolite (ZSM‐5‐F) as a function of seed content and crystallization temperature is studied. The crystallization time is reduced to 1.5 h and crystals with sizes below 200 nm and a Si/Al ratio of 23.6 are obtained. A zeolite with similar characteristics but synthesized in a hydroxyl medium (ZSM‐5‐OH) is used to evaluate ZSM‐5s synthesized in different crystallization media. Their physicochemical properties are compared and particular attention is paid to the nature, number, and distribution of silanol sites. The two zeolites exhibit similar number of Brφnsted acid sites; however the material synthesized in a hydroxyl medium contains a substantially larger number of surface and internal silanols that impact significantly its catalytic performance in methanol to hydrocarbon transformation. While the two materials exhibit similar selectivity in methanol transformations, the catalyst synthesized in fluoride medium shows superior activity and resistance to deactivation. The results suggest that seeded synthesis in a fluoride medium can be used for the preparation of superior zeolite catalysts.
Biomimetic Bidirectional Switchable Adhesive Inspired by the Gecko
Authors: Jin Kejia , Cremaldi Joseph C. , Erickson Jeffrey S. , Tian Yu , Israelachvili Jacob N. , Pesika Noshir S.
Published: August 2013

The gecko adhesive system has attracted significant attention since the discovery that van der Waals interactions, which are always present between surfaces, are predominantly responsible for their adhesion. The unique anisotropic frictional–adhesive capabilities of the gecko adhesive system originate from complex hierarchical structures and just as importantly, the anisotropic articulation of the structures. Here, by cleverly engineering asymmetric polymeric microstructures, a reusable switchable gecko‐like adhesive can be fabricated yielding steady high adhesion ( ≈ 1.25 N/cm2) and friction ( ≈ 2.8 N/cm2) forces when actuated for “gripping”, yet release easily with minimal adhesion ( ≈ 0.34 N/cm2) and friction (≈ 0.38 N/cm2) forces during detachment or “releasing”, over multiple attachment/detachment cycles, with a relatively small normal preload of 0.16 N/cm2 to initiate the adhesion. These adhesives can also be used to reversibly suspend weights from vertical (e.g., walls), and horizontal (e.g., ceilings) surfaces by simultaneously and judiciously activating anisotropic friction and adhesion forces. This design opens the way for new gecko‐like adhesive surfaces and articulation mechanisms that do not rely on intensive nanofabrication in order to recover the anisotropic tribological property of gecko adhesive pads, albeit with lower adhesive forces compared to geckos.
Selective Synthesis of Six‐Membered and Five‐Membered Spiro Compounds by Controlling the Molar Ratio of Ternary Gallium/Indium/Copper (Ga/In/Cu) Catalysts
Authors: Pang Tao , Sun Yu , Xue Wei‐Jian , Zhu Yan‐Ping , Yu Guang‐Ao , Wu An‐Xin
Published: August 2013

Selective syntheses of six‐membered and five‐membered spiro‐naphthalenones from the same starting substrates by controlling the molar ratio of ternary gallium/indium/copper (Ga/In/Cu) catalysts have been demonstrated. The method may have potential applications in natural product synthesis.

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Olefin‐Assisted Iron‐Catalyzed Alkylation of Aryl Chlorides
Authors: Gülak Samet , Gieshoff Tim N. , Jacobi von Wangelin Axel
Published: August 2013

A selective and operationally simple iron‐catalyzed cross‐coupling of aryl chlorides with alkylmagnesium halides has been developed. The reaction tolerates various functional groups and exhibits high chemoselectivity even in the presence of aryl bromides. Mechanistic studies indicate the essential role of the olefin substituent for substrate activation. Competing polymerization and reduction are effectively suppressed.

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Copper‐Catalyzed Intermolecular Oxidative Cyclization of Halo‐ alkynes: Synthesis of 2‐Halo‐substituted Imidazo[1,2‐a]pyridines, Imidazo[1,2‐a]pyrazines and Imidazo[1,2‐a]pyrimidines
Authors: Gao Yang , Yin Meizhou , Wu Wanqing , Huang Huawen , Jiang Huanfeng
Published: August 2013

An efficient copper‐catalyzed method for the synthesis of 2‐haloimidazopyridines with aminopyridines and haloalkynes using molecular oxygen as oxidant in a one‐pot manner has been developed. In this process, the reaction appears to be very general and suitable for the construction of a variety of 2‐halo‐substituted imidazopyridines, imidazopyrazines and imidazopyrimidines. The intermolecular oxidative diamination of haloalkynes was achieved for the first time. Importantly, the mild reaction conditions and the efficient conversion of the alkyl‐substituted haloalkynes are great improvements over the existing methods. Moreover, the resultant 2‐haloimidazo[1,2‐a]pyridines could be efficiently converted to other functionalized imidazopyridine products via substitution, coupling reactions and other transformations, which further indicates potential applications of this method in synthetic and pharmaceutical chemistry.

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Copper‐Catalyzed Aerobic Oxidative Carbocyclization– Ketonization Cascade: Selective Synthesis of Quinolinones
Authors: Xie Peng , Wang Zhi‐Qiang , Deng Guo‐Bo , Song Ren‐Jie , Xia Jia‐Dong , Hu Ming , Li Jin‐Heng
Published: August 2013

A new thematic extension method is described for the carbocyclization of α‐C(sp3)H bonds of amides with alkynes followed by ketonization of the alkynes that utilizes the inexpensive copper(II) acetoacetonate [Cu(acac)2] as catalyst under an oxygen atmosphere to synthesize quinolinones. It is noteworthy that the oxygen atom of the newly formed carbonyl group is from atmospheric molecular oxygen.

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Chemo‐, Regio‐ and Stereoselective Tricyclohexylphosphine‐Catalyzed [3+2] Cycloaddition of Enynes with [60]Fullerene Initiated by 1,4‐Michael Addition: Synthesis of Cyclopenteno[60]fullerenes and their Electrochemical Properties
Authors: Tseng Po‐Yen , Chuang Shih‐Ching
Published: August 2013

Herein we demonstrate a tricyclohexylphosphine‐catalyzed cycloaddition of (E)‐ or (Z)‐alkyl 5‐substituted phenylpent‐2‐en‐4‐ynoates with [60]fullerene to give cyclopentenofullerenes in good to excellent yields, through initial chemo‐ and regioselective 1,4‐addition of phosphines at the β‐carbon of the enyne substrates. The nucleophilic addition pattern of P(cHx)3 is found to be different from that of Gilman or Grignard reagents toward the studied enynes. The resulting cyclopentenofullerenes, characterized with spectrometric methods and single crystal X‐ray diffraction analysis, exhibit comparable or higher LUMO energy levels than a typical n‐type material, [6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM).

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