bluuebunny/crossref_metadata_2025 huggingface dataset:
Malaria in pregnancy in rural Gabon: a cross-sectional survey on the impact of seasonality in high-risk groups
Authors: Jäckle Mario J , Blumentrath Christian G , Zoleko Rella M , Akerey-Diop Daisy , Mackanga Jean-Rodolphe , Adegnika Ayôla A , Lell Bertrand , Matsiegui Pierre-Blaise , Kremsner Peter G , Mombo-Ngoma Ghyslain , Ramharter Michael
Published: November 2013

Background

Malaria remains one of the most important infectious diseases in pregnancy in sub-Saharan Africa. Whereas seasonal malaria chemoprevention is advocated as public health intervention for children in certain areas of highly seasonal malaria transmission, the impact of seasonality on malaria in pregnancy has not yet been investigated for stable, hyper-endemic transmission settings of Equatorial Africa. The aim of this study was to investigate the influence of seasonality on the prevalence of malaria in pregnancy in Gabon.

Methods

The study was conducted at a rural district hospital in Gabon between January 2008 and December 2011. At first antenatal care visits demographic data, parity, age, and gestational age of pregnant women were documented and thick blood smears were performed for the diagnosis of malaria. Seasonality and established risk factors were evaluated in univariate and multivariate analysis for their association with Plasmodium falciparum infection.

Results

1,661 pregnant women were enrolled in this study. Participants presenting during high transmission seasons were at significantly higher risk for P. falciparum infection compared to low transmission seasons (adjusted odds ratio [AOR] 1.91, 95% confidence interval [CI] 1.39-2.63, p < 0.001). Established risk factors including parity (AOR 0.45, CI 0.30-0.69, p < 0.001 for multipara versus paucipara) and age (AOR, CI and p-value for women aged 13–17, 18–22, 23–27 and ≥28 years, respectively: AOR 0.59, CI 0.40-0.88; AOR 0.57, CI 0.34-0.97; AOR 0.51, CI 0.29-0.91) were significant risk factors for P. falciparum infection. High-risk groups including nulli- and primipara and younger women aged 13–17 years showed a disproportionately increased risk for malaria in high transmission seasons from 17% to 64% prevalence in low and high transmission periods, respectively.

Conclusion

Seasonal variations lead to important differences in the risk for P. falciparum infection in pregnancy in the setting of central African regions with stable and hyper-endemic malaria transmission. The seasonal increase in malaria in pregnancy is most pronounced in high-risk groups constituted by young and pauciparous women. The evaluation of tailored seasonal prevention strategies for these high-risk populations may, therefore, be warranted.
Evaluation of health related quality of life in children with immune thrombocytopenia with the PedsQL™ 4.0 Generic Core Scales: a study on behalf of the pays de Loire pediatric hematology network
Authors: Strullu Marion , Rakotonjanahary Josué , Tarral Eliane , Savagner Christophe , Thomas Caroline , Méchinaud Françoise , Reguerre Yves , Poignant Sylvaine , Boutet Arnaud , Bassil Joachim , Médinger Dominique , Quemener Emmanuel , Young Nancy L , Rachieru Petronela , Klaassen Robert J , Pellier Isabelle
Published: November 2013

Background

Immune thrombocytopenia (ITP) is a childhood disorder that is often life-altering for children and their parents. Health related quality of life (HRQL) has never been chronologically monitored in children with ITP. We initiated a prospective study to assess HRQL from diagnosis to six months and define factors that influence this outcome in children with ITP.

Methods

73 children with acute ITP aged from 2 to 18 years were prospectively enrolled in the study. According to the presence of bleeding, they were or were not given a 4-day course of corticosteroid treatment. The PedsQL™ 4.0 Generic Core Scale was completed by children and parents upon their inclusion in the study and 6 months after diagnosis.

Results

Over the six month period, quality of life improved in terms of their global, physical and psychosocial well-being for 54.5%, 35.6% and 36.2% of patients respectively. This improvement is clinically relevant compared to scores at diagnosis, corresponding at least to a minimal clinically important difference (MCID). Factors such as sex, age, platelet count, bleeding scores, bone marrow aspiration and persistence of ITP at 6 months were not significantly associated with HRQL scores. However, preceding viral infection was identified to have an impact on HRQL.

Conclusions

This first longitudinal study assessing HRQL in children with ITP reveals a global improvement in PedSQL™ 4.0. However, these results should be considered with caution since our data also confirm that self-report HRQL scores are not influenced by any analyzed biologic or clinical parameters. Others tools, such as Kids’ ITP Tools, would probably be required to assess the HRQL of this population.

Trial registration

Trial registration clinical trials.gov Identifier: NCT00331357.
Effect of MWCNT size, carboxylation, and purification on in vitro and in vivo toxicity, inflammation and lung pathology
Authors: Hamilton Raymond F , Wu Zheqiong , Mitra Somenath , Shaw Pamela K , Holian Andrij
Published: November 2013

Background

Several properties of multi-walled carbon nanotubes (MWCNT) have the potential to affect their bioactivity. This study examined the in vitro and in vivo outcomes of the influence of diameter, length, purification and carboxylation (in vitro testing only) of MWCNT.

Methods

Three original ‘as received’ MWCNT that varied in size (diameter and length) were purified and functionalized by carboxylation. The resulting MWCNT were characterized and examined for cytotoxicity and inflammasome activation in vitro using THP-1 cells and primary alveolar macrophages from C57BL/6 mice. Oropharyngeal aspiration administration was used to deliver original MWCNT and in vivo bioactivity and lung retention was examined at 1 and 7 days.

Results

Studies with THP-1 macrophages demonstrated that increased length or diameter corresponded with increased bioactivity as measured by inflammasome activation. Purification had little effect on the original MWCNT, and functionalization completely eliminated bioactivity. Similar results were obtained using alveolar macrophages isolated from C57BL/6 mice. The in vivo studies demonstrated that all three original MWCNT caused similar neutrophil influx at one day, but increasing length or diameter resulted in the lavaged cells to release more inflammatory cytokines (IL-6, TNF-α, and IL-1β) ex vivo. Seven-day histology revealed that, consistent with the in vitro results, increasing width or length of MWCNT caused more severe pathology with the longest MWCNT causing the most severe inflammation. In addition, the same two larger MWCNT were retained more in the lung at 7 days.

Conclusions

Taken together, the results indicated that in vitro and in vivo bioactivity of MWCNT increased with diameter and length. Purification had no significant modifying effect from the original MWCNT. Functionalization by carboxylation completely eliminated the bioactive potential of the MWCNT regardless of size in in vitro testing.
Paediatric injuries at Bugando Medical Centre in Northwestern Tanzania: a prospective review of 150 cases
Authors: Simon Raymond , Gilyoma Japhet M , Dass Ramesh M , Mchembe Mabula D , Chalya Phillipo L
Published: November 2013

Background

Injuries continue to be the leading cause of death and disability for children. The is a paucity of published data on paediatric injuries in our local environment. This study describes the etiological spectrum, injury characteristics and treatment outcome of paediatric injuries in our local setting and provides baseline data for establishment of prevention strategies as well as treatment guidelines.

Methods

This was a descriptive cross-sectional study involving paediatric injury patients admitted to Bugando Medical Centre from August 2011 to April 2012. Statistical data analysis was done using SPSS version 17.0 and STATA version 12.0.

Results

A total of 150 patients were studied. The age of patients ranged from 1 month to 10 years with a median age of 5 years. The male to female ratio was 2.3:1. Road traffic accident was the most common cause of injury (39.3%) and motorcycle (71.2%) was responsible for the majority of road traffic accidents. Only 11 (7.3%) patients received pre-hospital care. The head /neck (32.7%) and musculoskeletal (28.0%) were the most frequent body region injured. Open wounds (51.4%), foreign bodies (31.3%) and fractures (17.3%) were the most common type of injuries sustained. The majority of patients 84 (56.0%) were treated surgically. Complication rate was 3.9%. The mean duration of hospitalization was 9.7 ± 13.1 days. Mortality rate was 12.7%. Age of the patient (< 5 years), late presentation and presence of complications were the main predictors of length of hospital stay (P < 0.001), whereas burn injuries, severe head injuries and severity of injury (Paediatric trauma score = 0–5) significantly predicted mortality (P < 0.0001).

Conclusion

Paediatric injuries resulting from road traffic accidents (RTAs) remain a major public health problem in this part of Tanzania. Urgent preventive measures targeting at reducing the occurrence of RTAs is necessary to reduce the incidence of paediatric injuries in this region.
Comparison of gene expression profiles in the blood, hippocampus and prefrontal cortex of rats
Authors: Witt Stephanie H , Sommer Wolfgang H , Hansson Anita C , Sticht Carsten , Rietschel Marcella , Witt Christian C
Published: November 2013

Background

The comparability of gene expression between blood and brain tissues is a central issue in neuropsychiatric research where the analysis of molecular mechanisms in the brain is of high importance for the understanding of the diseases and the discovery of biomarkers. However, the accessibility of brain tissue is limited. Therefore, knowledge about how easily accessible peripheral tissue, e. g. blood, is comparable to and reflects gene expression of brain regions will help to advance neuropsychiatric research.

Description

Gene expression in the blood, hippocampus (HC) and prefrontal cortex (PFC) of genetically identical rats was compared using a genome-wide Affymetrix gene expression microarray covering 29,215 expressed genes. A total of 56.8% of 15,717 expressed genes were co-expressed in blood and at least one brain tissue, while 55.3% of all genes were co-expressed in all three tissues simultaneously. The overlapping genes included a set of genes of relevance to neuropsychiatric diseases, in particular bipolar disorder, schizophrenia and alcohol addiction. These genes included CLOCK, COMT, FAAH, NPY, NR3C1, NRGN, PBRM1, TCF4, and SYNE.

Conclusions

This study provides baseline data on absolute gene expression and differences between gene expression in the blood, HC and PFC brain tissue of genetically identical rats. The present data represents a valuable resource for future studies as it might be used for first information on gene expression levels of genes of interest in blood and brain under baseline conditions. Limitations of our study comprise possible contamination of brain tissue with blood and the non-detection of genes with very low expression levels. Genes that are more highly expressed in the brain than in the blood are of particular interest since changes in their expression, e.g. due to disease status, or treatment, are likely to be detected in an experiment. In contrast, genes with higher expression in the blood than in the brain are less informative since their higher baseline levels could superimpose variation in brain.
The impact of body temperature abnormalities on the disease severity and outcome in patients with severe sepsis: an analysis from a multicenter, prospective survey of severe sepsis
Authors: Kushimoto Shigeki , Gando Satoshi , Saitoh Daizoh , Mayumi Toshihiko , Ogura Hiroshi , Fujishima Seitaro , Araki Tsunetoshi , Ikeda Hiroto , Kotani Joji , Miki Yasuo , Shiraishi Shin-ichiro , Suzuki Koichiro , Suzuki Yasushi , Takeyama Naoshi , Takuma Kiyotsugu , Tsuruta Ryosuke , Yamaguchi Yoshihiro , Yamashita Norio , Aikawa Naoki
Published: November 2013

Introduction

Abnormal body temperatures (Tb) are frequently seen in patients with severe sepsis. However, the relationship between Tb abnormalities and the severity of disease is not clear. This study investigated the impact of Tb on disease severity and outcomes in patients with severe sepsis.

Methods

We enrolled 624 patients with severe sepsis and grouped them into 6 categories according to their Tb at the time of enrollment. The temperature categories (≤35.5°C, 35.6–36.5°C, 36.6–37.5°C, 37.6–38.5°C, 38.6–39.5°C, ≥39.6°C) were based on the temperature data of the Acute Physiology and Chronic Health Evaluation II (APACHE II) scoring. We compared patient characteristics, physiological data, and mortality between groups.

Results

Patients with Tb of ≤36.5°C had significantly worse sequential organ failure assessment (SOFA) scores when compared with patients with Tb >37.5°C on the day of enrollment. Scores for APACHE II were also higher in patients with Tb ≤35.5°C when compared with patients with Tb >36.5°C. The 28-day and hospital mortality was significantly higher in patients with Tb ≤36.5°C. The difference in mortality rate was especially noticeable when patients with Tb ≤35.5°C were compared with patients who had Tb of >36.5°C. Although mortality did not relate to Tb ranges of ≥37.6°C as compared to reference range of 36.6–37.5°C, relative risk for 28-day mortality was significantly greater in patients with 35.6–36.5°C and ≤35.5°C (odds ratio; 2.032, 3.096, respectively). When patients were divided into groups based on the presence (≤36.5°C, n = 160) or absence (>36.5°C, n = 464) of hypothermia, disseminated intravascular coagulation (DIC) as well as SOFA and APACHE II scores were significantly higher in patients with hypothermia. Patients with hypothermia had significantly higher 28-day and hospital mortality rates than those without hypothermia (38.1% vs. 17.9% and 49.4% vs. 22.6%, respectively). The presence of hypothermia was an independent predictor of 28-day mortality, and the differences between patients with and without hypothermia were observed irrespective of the presence of septic shock.

Conclusions

In patients with severe sepsis, hypothermia (Tb ≤36.5°C) was associated with increased mortality and organ failure, irrespective of the presence of septic shock.

Trial registration

UMIN-CTR IDUMIN000008195
Reduction of Pm10 Emissions under Scenarios of Regulation and Availability of Natural Gas in the Bio Bio Region, Chile
Authors: Alegría Marcela , Mardones Cristian , Jiménez Jorge
Published: November 2013

The high level of industrial activity in the Bio Bio Region has led to local air pollution problems, due to the high emission levels of particulate matter. The feasibility of bringing liquefied natural gas to the region is under study. This paper compares a system of tradable emissions permits and command and control type regulation for industrial sources considering two alternatives for reducing PM10 emissions: Changing the fuel used to natural gas and incorporating air pollution control technologies. It was found that given certain fuel prices, the industries will likely change to natural gas without the need for regulation. Moreover, it was found the maximum price that could be paid whilst retaining the economic attractiveness of this alternative as a cost-effective option for emissions reductions.
Modern Environmentalism: A Longer Term Threat to Western Civilization
Authors: Carlin Alan
Published: November 2013

Modern environmentalists and particularly their academic supporters are attempting to change a number of economic and scientific ideas and principles fundamental to Western Civilization that have helped humans to achieve much of our dramatic progress in living standards in recent centuries, and, as a result, in environmental protection more recently. In the longer run this may well do more damage than even the wasted investments in inefficient and soon-to-be abandoned solar and wind farms. Even limited application of their ideology on energy would result in decreased consumer choice, economic growth, and living standards. Without an economic and scientific basis, modern environmentalism cannot rationally claim that its proposed climate policies would make the world better off. It is just another ideology trying to pretend that it has a scientific and economic basis; these pretensions lead to many of the problems discussed here. Objective scientific and economic analysis is needed of past and present policy proposals by modern environmentalists to correct errors and avoid future ones.
The Impact of a Multilateral Electricity Generation Tax on Competitiveness in Southern Africa: A Computable General Equilibrium Analysis Using the Global Trade Analysis Project
Authors: Seymore R. , van Heerden J. H. , Mabugu M.
Published: November 2013

The South African Government announced, in the 2008 Budget Review, the intention to tax the generation of electricity from non-renewable sources with 2c/kWh. The intention of the tax is to serve a dual purpose of managing the potential electricity shortages in South Africa and to protect the environment. The primary objective of this paper is to evaluate the impact of an electricity generation tax on the international competitiveness of South Africa. Specifically, different scenarios are assessed to establish whether the loss of competitiveness can be negated through an international, multilateral electricity generation tax. The paper firstly considers the beneficial impact of environmental taxation on the competitiveness of a country. We subsequently apply the Global Trade Analysis Project (GTAP) model to evaluate the impact of an electricity generation tax on the competitiveness of South Africa, given multilateral taxes on SACU, SADC and European Union economies. It is shown that an electricity generation tax will indeed affect the competitiveness of South Africa in a negative way. Furthermore, SACU and SADC wide implementation will marginally reinforce these negative effects. However, a multilateral electricity generation tax across SACU or SADC countries will result in emission reductions, but lower than in the case of a unilateral electricity generation tax. In contrast, the cost to the South African economy could be limited, if the European Union would follow suit and implement an electricity generation tax. One could therefore argue in favour of global rules for environmental taxes, since this will ensure minimum negative competitiveness effects on participating countries.
Measuring the Impact Sound Reduction at a Compact Measurement Setup — Design, Results and Uncertainties
Authors: Schmidt Jan-Henning , Wittstock Volker , Foret Rémy , Fichtel Christoph , Scheck Jochen
Published: November 2013

A method to measure the impact sound reduction at a compact measurement setup (COMET) is developed at the Physikalisch-Technische Bundesanstalt. This paper presents the setup and the test procedure with respect to a physical model of impact sound reduction for locally reacting floor coverings. The impact sound reductions of many floor coverings obtained at different test facilities according to ISO 10140 and obtained at different COMETs are compared. Under consideration of the standard uncertainties, an alternative procedure to calculate the impact sound reduction at the COMET is proposed which is different to the procedure in the current version of the standard describing the COMET (ISO/DIS 16251-1).
The Influence of the Wall Cavity on the Transmission Loss of Wall Systems — Experimental Trends
Authors: Cambridge Jason E. , Davy John L. , Pearse John
Published: November 2013

Numerous experimental investigations have been conducted into the sound transmission loss of double leaf wall systems. From these investigations, it has been observed that the properties of the wall panels, material placed within the wall cavity as well as the type of wall connections used, greatly influence the sound transmission through the wall system. In all of these cases the wall cavity greatly affects the extent of this influence and in some cases it can even nullify their effect when changes are made. In this paper the influence of the wall cavity based on experimental trends is investigated. The investigation revealed that a wide variety of conclusions were obtained by different researchers concerning the role of the cavity and the properties of any associated sound absorption material on the sound transmission loss through double leaf wall systems. Consequently recommendations about the ways in which sound transmission through cavity systems can be improved should always be qualified with regard to the specific frequency range of interest, type of sound absorption material, wall panel and stud characteristics.
Incorporating Residual Strains in the Flexural Rigidity of RC Members with Varying Degrees of Prestress and Cracking
Authors: Knight D. , Visintin P. , Oehlers D.J. , Jumaat M.Z.
Published: November 2013

The deformation of reinforced concrete columns and beams is controlled by the variation of the flexural rigidity (EI) both along the member and with applied loads and time. Currently, the moment-curvature (M/χ) approach is used to quantify EI. Prior to cracking, the M/χ approach provides a pure mechanics based solution for EI; that is, the only components of the model that have to be determined empirically are the material stress-strain relationships. However after cracking, the M/χ approach has to be semi-empirical, that is EI has to be determined empirically because the M/χ approach cannot simulate the mechanics of tension-stiffening. An alternative approach for quantifying EI using a moment-rotation (M/θ) approach is described in this paper. It is shown that the M/θ approach gives exactly the same results as the M/χ approach prior to cracking but after cracking has an advantage over the M/χ approach in that it can quantify the mechanics of tension-stiffening, that is allow for bond slip and its effect on crack spacing and crack widths. This paper deals with the mechanics of incorporating creep, shrinkage, prestress, relaxation and thermal gradients (broadly referred to as residual strains) on the flexural rigidity of RC beams and columns at all levels of loading prior to concrete softening.
Sensitivity Analysis of Nonlinear Behaviour of Infill-Frames under In-Plane and Out-Of-Plane Loading
Authors: Mohyeddin Alireza , Goldsworthy Helen M , Gad Emad F
Published: November 2013

This paper addresses the sensitivity of the in-plane and out-of-plane behaviour of reinforced-concrete (RC) frames with masonry infill panels to a select number of material related parameters. Instead of general conclusions, the intention is to facilitate a deeper insight into the behaviour of infill-frames at a micro level over a wide range of drift values. A script, which has recently been developed, is used to generate the finite element (FE) models of an infill-frame with desired geometric and mechanical properties. Also, the same three-dimensional FE model is used for both in-plane and out-of-plane analyses of infill-frames. The sensitivity analyses are conducted in three sequential parts: the analyses of a masonry bare wall under one-way bending, the analyses of an infill-frame under out-of-plane loading and the sensitivity analyses of an infill-frame under in-plane loading. A simple method is delineated to overcome convergence issues which are related to the highly nonlinear finite element models to be solved using the Newton-Raphson algorithm.
Seismic Response of a Concrete Filled Steel Tubular Arch Bridge to Spatially Varying Ground Motions Including Local Site Effect
Authors: Bi Kaiming , Hao Hong , Ren Wei-Xin
Published: November 2013

The construction of concrete filled steel tubular (CFST) arch bridge has become widespread all over the world and especially in China since 1990. This paper studies the nonlinear seismic response of a CFST arch bridge on a canyon site subjected to multi-component spatially varying ground motions. The three-dimensional (3D) finite element (FE) model of the CFST arch bridge is developed with consideration of the material and geometric nonlinearities of the arch ribs. The spatially varying ground motions with consideration of wave passage effect, coherency loss effect and local site effect are stochastically simulated based on the combined one-dimensional (1D) wave propagation theory and spectral representation method. The effects of multi-component earthquake excitations, spatial variations of ground motions and varying site conditions on the seismic response of the CFST arch bridge are analysed. Numerical results show that for a reliable seismic analysis of a CFST arch bridge, multi-component earthquake excitations with consideration of ground motion spatial variations and local soil conditions should be considered.
Experimental study of indirect tensile strength of calcareous coal gangue mixture
Authors: Zhang Yapeng , Meng Wenqing , Zhang Zhifei
Published: November 2013

The calcareous coal gangue, fly ash, lime powder and a small amount of cement mixture, which are selected from the Hanxing area, are mixed into a calcareous coal gangue mixture. An experimental study was done on the cleavage strength of this mixture. According to the method of uniform design, 8 groups of test matching scheme of calcareous coal gangue mixture were designed. The experiments were conducted on calcareous coal gangue mixtures in various matching proportions. The experimental results are analyzed by regression analysis model. The regression equation between the calcareous coal gangue mixture indirect tensile strength (cleavage strength) and the admixture dosage is established. By using the regression analysis model, the influence of the dosage of fly ash, calces, and cement on the calcareous coal gangue mixture's indirect tensile strength is analyzed.
Direct Numerical Simulation of Particles-Bubbles Collisions Kernel in Homogeneous Isotropic Turbulence
Authors: Fayed Hassan E. , Ragab Saad A.
Published: November 2013

Particles and bubbles suspended in homogeneous isotropic turbulence are tracked and their collisions frequency is determined as a function of particle Stokes number. The carrier phase velocity fluctuations are determined by Direct Numerical Simulations (DNS). The effects of the dispersed phases on the carrier phase are neglected. Particles and bubbles of sizes on the order of Kolmogorov length scale are treated as point masses. In addition to Stokes drag, the pressure gradient in the carrier phase and added-mass forces are also included. Equations of motion of dispersed phases are integrated simultaneously with the equations of the carrier phase using the same time stepping scheme. The collision model used here allows overlap of particles and bubbles. Simulations for three turbulence Reynolds numbers ReΛ = 57, 77, and 96 have been performed. Collisions kernel, radial relative velocity, and radial distribution function found by DNS are compared to theoretical models over a range of particle Stokes number. Comparisons are made with Zaichik et al. [22] model, which is applicable to heavy particles, and Zaichik et al. [23] model which is valid for an arbitrary Stokes number. Zaichik et al. [23] is essentially a model for the radial relative velocity, and for the purpose of computing the collision kernel, it assumes the radial distribution function to be one. In general, good agreement between DNS and Zaichik et al. models is obtained for radial relative velocity for both particle-particle and particle-bubble collisions. The DNS results show that around Stokes number of unity particles of the same group undergo expected preferential concentration while particles and bubbles are segregated. The segregation behavior of particles and bubbles leads to a radial distribution function that is less than one. Existing theoretical models do not account for effects of this segregation behavior of particles and bubbles on the radial distribution function.
An Investigation into Air-Sand-Water Three-Phase Flow through the Sandblasting Nozzle
Authors: Abbasalizadeh M. , Mirzaee I. , Shirvani A. , Mebrahtu H. , Shirvani H.
Published: November 2013

The numerical analysis of air-sand-water three-phase turbulent flow through converging-diverging nozzle is investigated for employing on sandblasting systems. For this purpose-dispersed flow of air-sand-water by various airs inlet pressures and different mass flow rates of sand particles and water droplets were considered. Two-way turbulence coupling between particles/droplets and airflow as well as interference between the incident streams of particles and rebounded from the wall were applied in the numerical model. In addition, the shock wave, which is produced in supersonic flow at diverging part of nozzle, was considered. In this study the Realizable k-ε and Discrete Phase models were utilized for simulating of multi-phase turbulent flow through the converging-diverging nozzle. As review of literature indicates there is not any experimental or analytical data on three-phase flow through the nozzle, consequently for validation of model, the same turbulent and multi-phase models were utilized on air-water two-phase flow. The obtained results were in good agreement with the experimental data. According to the results of three-phase flow simulation, the averaged exhaust momentum of sand particles had inverse proportion with water mass flow rate, and increasing of air inlet pressure had significant effect on mean exhaust velocity of sand particles.
Optimization of Particle Search Algorithm for CFD-DEM Simulations
Authors: Baryshev G. , Khawaja H. , Moatamedi M.
Published: November 2013

Discrete element method has numerous applications in particle physics. However, simulating particles as discrete entities can become costly for large systems. In time-driven DEM simulation most computation time is taken by contact search stage. We propose an efficient collision detection method which is based on sorting particles by their coordinates. Using multiple sorting criteria allows minimizing number of potential neighbours and defines fitness of this approach for simulation of massive systems in 3D. This method is compared to a common approach that consists of placing particles onto a grid of cells. Advantage of the new approach is independence of simulation parameters upon particle radius and domain size.
PROBLEMAS DE ESTIMACIÓN DE GRANDES CANTIDADES: MODELIZACIÓN E INFLUENCIA DEL CONTEXTO
Authors: Albarracín Lluís , Gorgorió Núria
Published: November 2013

En este artículo introducimos los problemas de estimación de grandes cantidades. Nos proponemos estudiar la presencia de procesos de modelización matemática y la influencia del contexto de estos problemas en las propuestas de resolución de alumnos de Educación Secundaria. A partir de un análisis cualitativo de diferentes dimensiones de las propuestas recogidas (respuesta orientada a la pregunta, estrategias, éxito en la resolución), estudiamos la existencia de relaciones entre las estrategias propuestas por los alumnos y los contextos planteados en las situaciones de los enunciados de los problemas, y la modelización de las situaciones planteadas. De los datos recogidos en nuestro estudio se deduce que el contexto puede influir en las propuestas de resolución que hacen los alumnos. Concluimos que este tipo de problemas pueden ser utilizados para introducir la modelización en las aulas.
AS MATEMÁTICAS MODERNAS: UM ENSAIO SOBRE OS MODOS DE PRODUÇÃO DE SIGNIFICADO AO(S) MOVIMENTO(S) NO ENSINO PRIMÁRIO BRASILEIRO
Authors: Souza Luzia Aparecida de , Marafioti Garnica Antonio Vicente
Published: November 2013

La intención principal de este artículo es discutir la producción de significados de lo que se conoce como Movimiento Matemática Moderna. A partir de fuentes como documentos escolares y entrevistas con antiguos profesores, principalmente, se intenta resaltar la pluralidad de perspectivas – complementarias y opuestas– que surgen cuando los profesores hacen referencia al Movimiento y cómo, a partir de este proceso de significación, aceptan, subvierten o adaptan, en sus prácticas de enseñanza, las directrices que les son impuestas. Para la recolección de testimonios orales, seguimos como metodología los presupuestos de la Historia Oral. La fundamentación teórica que todo el artículo sigue son las directrices de la Hermenéutica de Paul Ricoeur, la Hermenéutica de la profundidad de John Thompson y las indicaciones del análisis de narrativa de Bolívar.
Do Private Equity Returns Result from Wealth Transfers and Short-Termism? Evidence from a Comprehensive Sample of Large Buyouts
Authors: Harford Jarrad , Kolasinski Adam
Published: November 2013

We test whether the well-documented high returns of private equity sponsors result from wealth transfers from other financial claimants and counterparties and from a focus on short-term profits at the expense of long-term value. Debt investors who finance buyouts, as well as buyers of private equity portfolio companies, represent the two potential sources of wealth transfers. However, we find that, on average, public companies benefit when they buy financial sponsors' portfolio companies, experiencing positive abnormal returns upon the announcement of the acquisition and long-run posttransaction abnormal returns indistinguishable from zero. We further find that large portfolio company payouts to private equity on average have no relation to future portfolio company distress, suggesting that debt investors are not suffering systematic wealth losses either. However, we find some evidence of wealth transfers from both strategic buyers and debt investors in some special situations. Finally, we find that portfolio companies invest no differently than a matched sample of public control firms, even when they are not profitable, an observation inconsistent with short-termism.

This paper was accepted by Brad Barber, finance.
Note to Self: Note Taking and the Control of Information
Authors: Brabazon Tara
Published: November 2013

Many areas of teaching and learning have been transformed through digitisation. The mobility of content and the capacity to cut and paste text has saved time for students and teachers. However, the impact on note taking as a mode of information management is under-researched. This article explores the ideological role of the software programme PowerPoint for note taking in the current classroom, placing attention on how and why students are now photographing slides with smart phones. The consequences of this disintermediation in information management are assessed alongside the best use of PowerPoint to enable the development of visual literacy rather than the deskilling of teaching and learning.
Convergence of metrics under self-dual Weyl tensor and scalar curvature bounds
Authors: Xu Yiyan
Published: November 2013

We establish a C
1,α-compactness theorem for metrics
with bounded self-dual Weyl tensor and scalar curvature. The main ingredient is the C
1,α-harmonic radius estimate, where
a blow up analysis as in [Invent. Math. 102 (1990), 429–445] is used. Our result is
motivated by, and may be applied to, the Calabi flow on complex
surfaces.
Fetal behavioral states are stable over daytime – evidence by longitudinal and cross-sectional fetal biomagnetic recordings
Authors: Sonanini Alessandra , Stingl Krunoslav , Preissl Hubert , Brändle Johanna , Hoopmann Markus , Kagan Oliver , Wallwiener Diethelm , Abele Harald , Kiefer-Schmidt Isabelle
Published: November 2013

Aims: Fetal behavioral states can be distinguished by biomagnetic recordings. We performed a longitudinal and a cross-sectional study to address the question whether the distribution of fetal behavioral states changes during the daytime.

Methods: For the longitudinal study, 32 magnetocardiographic recordings were performed on a singleton pregnancy on a weekly basis. On each examination day, two recordings were performed at different times between 25 and 40 weeks of gestation. For the cross-sectional study, fetal magnetocardiograms (fMCG) were recorded in a group of 32 singleton pregnancies matched for gestational age and daytime to the longitudinal study. The recordings were separated into two gestational age groups (less and more than 32 weeks). Fetal behavioral states were extracted from actocardiograms generated from MCG.

Results: No significant differences in fetal behavioral state distribution were found between morning and afternoon recordings in either the longitudinal or the cross-sectional study.

Conclusion: This is the first magnetographic approach to show that daytime does not influence the distribution of fetal behavioral states in standardized recordings of 30 min length. This result implies that fetal magnetography recordings at normal daytimes can be combined without a bias and future recordings can be conducted independently of daytime as long as the varying behavioral states are generally taken into account during analysis.
N-Cadherin Sustains Motility and Polarity of Future Cortical Interneurons during Tangential Migration
Authors: Luccardini Camilla , Hennekinne Laetitia , Viou Lucie , Yanagida Mitsutoshi , Murakami Fujio , Kessaris Nicoletta , Ma Xufei , Adelstein Robert S. , Mège René-Marc , Métin Christine
Published: November 2013

In the developing brain, cortical GABAergic interneurons migrate long distances from the medial ganglionic eminence (MGE) in which they are generated, to the cortex in which they settle. MGE cells express the cell adhesion molecule N-cadherin, a homophilic cell–cell adhesion molecule that regulates numerous steps of brain development, from neuroepithelium morphogenesis to synapse formation. N-cadherin is also expressed in embryonic territories crossed by MGE cells during their migration. In this study, we demonstrate that N-cadherin is a key player in the long-distance migration of future cortical interneurons. Using N-cadherin-coated substrate, we show that N-cadherin-dependent adhesion promotes the migration of mouse MGE cellsin vitro. Conversely, mouse MGE cells electroporated with a construct interfering with cadherin function show reduced cell motility, leading process instability, and impaired polarization associated with abnormal myosin IIB dynamics.In vivo, the capability of electroporated MGE cells to invade the developing cortical plate is altered. Using genetic ablation ofN-cadherinin mouse embryos, we show thatN-cadherin-depleted MGEs are severely disorganized. MGE cells hardly exit the disorganized proliferative area.N-cadherinablation at the postmitotic stage, which does not affect MGE morphogenesis, alters MGE cell motility and directionality. The tangential migration to the cortex ofN-cadherinablated MGE cells is delayed, and their radial migration within the cortical plate is perturbed. Altogether, these results identify N-cadherin as a pivotal adhesion substrate that activates cell motility in future cortical interneurons and maintains cell polarity over their long-distance migration to the developing cortex.
Ventromedial Prefrontal Cortex Pyramidal Cells Have a Temporal Dynamic Role in Recall and Extinction of Cocaine-Associated Memory
Authors: Van den Oever Michel C. , Rotaru Diana C. , Heinsbroek Jasper A. , Gouwenberg Yvonne , Deisseroth Karl , Stuber Garret D. , Mansvelder Huibert D. , Smit August B.
Published: November 2013

In addicts, associative memories related to the rewarding effects of drugs of abuse can evoke powerful craving and drug seeking urges, but effective treatment to suppress these memories is not available. Detailed insight into the neural circuitry that mediates expression of drug-associated memory is therefore of crucial importance. Substantial evidence from rodent models of addictive behavior points to the involvement of the ventromedial prefrontal cortex (vmPFC) in conditioned drug seeking, but specific knowledge of the temporal role of vmPFC pyramidal cells is lacking. To this end, we used an optogenetics approach to probe the involvement of vmPFC pyramidal cells in expression of a recent and remote conditioned cocaine memory. In mice, we expressed Channelrhodopsin-2 (ChR2) or Halorhodopsin (eNpHR3.0) in pyramidal cells of the vmPFC and studied the effect of activation or inhibition of these cells during expression of a cocaine-contextual memory on days 1–2 (recent) and ∼3 weeks (remote) after conditioning. Whereas optical activation of pyramidal cells facilitated extinction of remote memory, without affecting recent memory, inhibition of pyramidal cells acutely impaired recall of recent cocaine memory, without affecting recall of remote memory. In addition, we found that silencing pyramidal cells blocked extinction learning at the remote memory time-point. We provide causal evidence of a critical time-dependent switch in the contribution of vmPFC pyramidal cells to recall and extinction of cocaine-associated memory, indicating that the circuitry that controls expression of cocaine memories reorganizes over time.
Cortical Reorganization after Long-Term Adaptation to Retinal Lesions in Humans
Authors: Chung Susana T. L.
Published: November 2013

Single-unit recordings demonstrated that the adult mammalian visual cortex is capable of reorganizing after induced retinal lesions. In humans, whether the adult cortex is capable of reorganizing has only been studied using functional magnetic resonance imaging, with equivocal results. Here, we exploited the phenomenon of visual crowding, a major limitation on object recognition, to show that, in humans with long-standing retinal (macular) lesions that afflict the fovea and thus use their peripheral vision exclusively, the signature properties of crowding are distinctly different from those of the normal periphery. Crowding refers to the inability to recognize objects when the object spacing is smaller than the critical spacing. Critical spacing depends only on the retinal location of the object, scales linearly with its distance from the fovea, and is approximately two times larger in the radial than the tangential direction with respect to the fovea, thus demonstrating the signature radial–tangential anisotropy of the crowding zone. Using retinal imaging combined with behavioral measurements, we mapped out the crowding zone at the precise peripheral retinal locations adopted by individuals with macular lesions as the new visual reference loci. At these loci, the critical spacings are substantially smaller along the radial direction than expected based on the normal periphery, resulting in a lower scaling of critical spacing with the eccentricity of the peripheral locus and a loss in the signature radial–tangential anisotropy of the crowding zone. These results imply a fundamental difference in the substrate of cortical processing in object recognition following long-term adaptation to macular lesions.
Glial Control of Endocannabinoid Heterosynaptic Modulation in Hypothalamic Magnocellular Neuroendocrine Cells
Authors: Di Shi , Popescu Ion R. , Tasker Jeffrey G.
Published: November 2013

Cannabinoid receptors are functionally operant at both glutamate and GABA synapses on hypothalamic magnocellular neuroendocrine cells; however, retrograde endocannabinoid actions are evoked at only glutamate synapses. We tested whether the functional targeting of evoked retrograde endocannabinoid actions to glutamate, and not GABA, synapses on magnocellular neurons is the result of the spatial restriction of extracellular endocannabinoids by astrocytes. Whole-cell GABA synaptic currents were recorded in magnocellular neurons in rat hypothalamic slices following manipulations to reduce glial buffering of extracellular signals. Depolarization- and glucocorticoid-evoked retrograde endocannabinoid suppression of synaptic GABA release was not detected under normal conditions, but occurred in both oxytocin and vasopressin neurons under conditions of attenuated glial coverage and depressed glial metabolic function, suggesting an emergent endocannabinoid modulation of GABA synapses with the loss of astrocyte function. Tonic endocannabinoid suppression of GABA release was insensitive to glial manipulation. Blocking cannabinoid transport mimicked, and increasing the extracellular viscosity reversed, the effect of suppressed glial buffering on the endocannabinoid modulation of GABA release. Evoked, but not tonic, endocannabinoid modulation of GABA synapses was mediated by 2-arachidonoylglycerol. Therefore, depolarization- and glucocorticoid-evoked 2-arachidonoylglycerol release from magnocellular neurons is spatially restricted to glutamate synapses by astrocytes, but spills over onto GABA synapses under conditions of reduced astrocyte buffering; tonic endocannabinoid modulation of GABA release, in contrast, is likely mediated by anandamide and is insensitive to astrocytic buffering. Astrocytes, therefore, provide dynamic control of stimulus-evoked 2-arachidonoylglycerol, but not tonic anandamide, regulation of GABA synaptic inputs to magnocellular neuroendocrine cells under different physiological conditions.
The σ-1 Receptor Interacts Directly with GluN1 But Not GluN2A in the GluN1/GluN2A NMDA Receptor
Authors: Balasuriya Dilshan , Stewart Andrew P. , Edwardson J. Michael
Published: November 2013

The σ-1 receptor (Sig1R) is widely expressed in the CNS, where it has a neuroprotective role in ischemia and stroke and an involvement in schizophrenia. The Sig1R interacts functionally with a variety of ion channels, including the NMDA receptor (NMDAR). Here, we used atomic force microscopy (AFM) imaging to investigate the interaction between the Sig1R and the NMDAR. The Sig1R bound directly to GluN1/GluN2A NMDAR heterotetramers. Furthermore, the mean angle between pairs of bound Sig1Rs was 72°. This result suggested that the Sig1R interacts with either GluN1 or GluN2A, but not both, and supports our recent demonstration that the NMDAR subunits adopt an adjacent (i.e., 1/1/2/2) arrangement. The Sig1R could be coisolated with GluN1 but not with GluN2A, indicating that GluN1 is its specific target within the NMDAR. Consistent with this conclusion, AFM imaging of coisolated Sig1R and GluN1 revealed GluN1 dimers decorated with Sig1Rs.In situproximity ligation assays demonstrated that the Sig1R interacts with GluN1 (but not with GluN2A) within intact cells and also that its C terminus is extracellular. We conclude that the Sig1R binds to the GluN1/GluN2A NMDAR specifically via the GluN1 subunit. This interaction likely accounts for at least some of the modulatory effects of Sig1R ligands on the NMDAR.