bluuebunny/crossref_metadata_2025 huggingface dataset:
Multiple soliton solutions for the integrable couplings of the KdV and the KP equations
Authors: Wazwaz Abdul-Majid
Published: February 2013

In this work, we study the nonlinear integrable couplings of the KdV and the Kadomtsev-Petviashvili (KP) equations. The simplified Hirota’s method will be used for this study. We show that these couplings possess multiple soliton solutions the same as the multiple soliton solutions of the KdV and the KP equations, but differ only in the coefficients of the transformation used. This difference exhibits soliton solutions for some equations and anti-soliton solutions for others.
A Photovoltaic Power System Using a High Step-up Converter for DC Load Applications
Authors: Tseng Sheng-Yu , Wang Hung-Yuan
Published: February 2013

This paper presents a power system using a high step-up converter for dc load applications. The high step-up converter adopts a boost converter with interleaved mode and a coupled inductor to raise its powering ability and increase its step-up voltage ratio, respectively. In order to increase conversion efficiency, an active clamp circuit is introduced into the proposed one to provide soft-switching features to reduce switching losses. Moreover, switches in the converter and active clamp circuit are integrated with a synchronous switching technique to reduce circuit complexity and component counts, resulting in a lower cost and smaller volume. A perturb and observe method is adopted to extract the maximum power from photovoltaic (PV) arrays. Furthermore, a microchip associated with PWM IC is used to implement maximum power point tracking operation, voltage regulation and power management. Finally, a prototype PV power system with 400 V/6 A has been implemented for verifying the feasibility of the proposed PV power system. It is shown to be suitable for PV energy conversion applications when the duty ratios of switches in the dc/dc converter are less than 0.5.
Effect of Nanoencapsulated Vitamin B1 Derivative on Inhibition of Both Mycelial Growth and Spore Germination of Fusarium oxysporum f. sp. raphani
Authors: Cho Jeong , Seo Yong , Yim Tae , Lee Hyeon
Published: February 2013

Nanoencapsulation of thiamine dilauryl sulfate (TDS), a vitamin B1 derivative, was proved to effectively inhibit the spore germination of Fusarium oxysporum f. sp. raphani (F. oxysporum), as well as mycelial growth. The average diameter of nanoparticles was measured as 136 nm by being encapsulated with an edible encapsulant, lecithin, whose encapsulation efficiency was about 55% in containing 200 ppm of TDS concentration: the 100 ppm TDS nanoparticle solution showed a mycelial growth inhibition rate of 59%. These results were about similar or even better than the cases of treating 100 ppm of dazomet, a positive antifungal control (64%). Moreover, kinetic analysis of inhibiting spore germination were estimated as 6.6% reduction of spore germination rates after 24 h treatment, which were 3.3% similar to the case of treating 100 ppm of a positive control (dazomet) for the same treatment time. It was also found that TDS itself could work as an antifungal agent by inhibiting both mycelial growth and spore germination, even though its efficacy was lower than those of nanoparticles. Nanoparticles especially played a more efficient role in limiting the spore germination, due to their easy penetration into hard cell membranes and long resident time on the surface of the spore shell walls. In this work, it was first demonstrated that the nanoparticle of TDS not a harmful chemical can control the growth of F. oxysporum by using a lower dosage than commercial herbicides, as well as the inhibiting mechanism of the TDS. However, field trials of the TDS nanoparticles encapsulated with lecithin should be further studied to be effectively used for field applications.
Brazilin Inhibits Growth and Induces Apoptosis in Human Glioblastoma Cells
Authors: Lee Dae-Young , Lee Mi-Kyoung , Kim Geum-Soog , Noh Hyung-Jun , Lee Min-Ho
Published: February 2013

Brazilin, isolated from the methanol extract of the heart wood of Caesalpinia sappan, sensitizes cancer cells to apoptosis. Glioblastoma multiforme (GBM), which accounts for most cases of central nervous system malignancy, has a very poor prognosis and lacks effective therapeutic interventions. We, therefore, investigated the effects of different concentrations of and different periods of exposure to brazilin on cell proliferation and apoptosis in the glioma U87 cell line. Cell proliferation was investigated by MTT assays and growth curve analysis, apoptosis was assessed by FACS analysis and western blot studies. Brazilin showed dose-dependent inhibition of cell proliferation and induction of apoptosis in glioma cells. It also increased the ratio of cleaved poly-(ADP)-ribose polymerase and decreased the expression of caspase-3 and caspase-7.
Virtual and Remote Robotic Laboratory Using EJS, MATLAB and LabVIEW
Authors: Chaos Dictino , Chacón Jesús , Lopez-Orozco Jose , Dormido Sebastián
Published: February 2013

This paper describes the design and implementation of a virtual and remote laboratory based on Easy Java Simulations (EJS) and LabVIEW. The main application of this laboratory is to improve the study of sensors in Mobile Robotics, dealing with the problems that arise on the real world experiments. This laboratory allows the user to work from their homes, tele-operating a real robot that takes measurements from its sensors in order to obtain a map of its environment. In addition, the application allows interacting with a robot simulation (virtual laboratory) or with a real robot (remote laboratory), with the same simple and intuitive graphical user interface in EJS. Thus, students can develop signal processing and control algorithms for the robot in simulation and then deploy them on the real robot for testing purposes. Practical examples of application of the laboratory on the inter-University Master of Systems Engineering and Automatic Control are presented.
On the Effects of the Lateral Strains on the Fiber Bragg Grating Response
Authors: Lai Marco , Karalekas Dimitris , Botsis John
Published: February 2013

In this paper, a combined experimental-numerical based work was undertaken to investigate the Bragg wavelength shift response of an embedded FBG sensor when subjected to different conditions of multi-axial loading (deformation). The following cases are examined: (a) when an isotropic host material with no constrains on planes normal to the embedded sensor’s axis is biaxially loaded, (b) when the same isotropic host material is subjected to hydrostatic pressure and (c) when the hydrostatically loaded host material is an anisotropic one, as in the case of a composite material, where the optical fiber is embedded along the reinforcing fibers. The comparison of the experimental results and the finite element simulations shows that, when the axial strain on the FBG sensor is the dominant component, the standard wavelength-shift strain relation can be used even if large lateral strains apply on the sensor. However when this is not the case, large errors may be introduced in the conversion of the wavelength to axial strains on the fiber. This situation arises when the FBG is placed parallel to high modulus reinforcing fibers of a polymer composite.
Design and Implementation of Students’ Information System for Tertiary Institutions Using Neural Networks
Authors: Afolayan Obiniyi Ayodele , Absalom Ezugwu El-Shamir
Published: February 2013

This paper identifies the causes associated with delays in processing and releasing results in tertiary institutions. An enhanced computer program for result computation integrated with a database for storage of processed results simplifies a university grading system and overcomes the short-comings of existing packages. The system takes interdepartmental collaboration and alliances into consideration, over a network that speeds up collection of processed results from designated departments through an improved centralized database system. An empirical evaluation of the system shows that it expedites processing of results and transcripts at various levels and management of and access to student results on-line. The technological approach for the implementation of the proposed system is based on open source solutions. Apache is used as Web server extended with PHP for server side processing. In recognition of the confidentiality of data contained in the system, communication networks are protected with open-ssl library for data encryption and role-based authentication. This system increases efficient service delivery and benefits both administration and students.
The Application of Machine Learning Technique for Malaria Diagnosis
Authors: Ugwu C. , Onyejegbu N. L , Obagbuwa I. C
Published: February 2013

Healthcare delivery in African nations has long been a worldwide issue, which is why the United Nations and World Health Organization seek for ways to alleviate this problem and thereby reduce the number of lives that are lost every year due to poor health facilities and inadequate health care administration. Healthcare delivery concerns are most predominant in Nigeria and it became imperatively clear that the system of medical diagnosis must be automated. This paper explores the potential of machine learning technique (decision tree) in development of a malaria diagnostic system. The decision tree algorithm was used in the development of the knowledge base. Microsoft Access and Java programming language were used for database and user interfaces, respectively. During the diagnosis, symptoms are provided by the patient in the diagnostic system and a match is found in the knowledge base.
An Empirical Investigation of Environmental Kuznets Curve in Nigeria
Authors: Ayadi Folorunso Sunday
Published: February 2013

The possibility of the existence of environmental Kuznet curve (EKC) has been debated extensively in the literature. The reality of EKC is that, by pursuing growth in income, environmental objectives can be simultaneously accomplished without initiating extra intervention tools. Various studies have been conducted on the existence of EKC without any consensus. Therefore, in this paper, the author analyzes whether or not EKC exists and its shape. In this study, the author uses an explanatory variable to in the model, which is population density, showing the level of resilience of the environment to pollution. However, this research found that at the lower stage of income, environmental degradation declined with income growth, rises as income grew further, then declined. However, income did not contribute significantly toward the explanation of environmental degradation like population density. This research found no synergies between addressing poverty and environmental problems in Nigeria. Therefore, complementary environmental policies must be put in place when addressing poverty. Lastly, there are different shapes of the relationship between income growth and various measures of pollution and environmental degradation, and developing countries must recognize that no one size fits all in this relationship.
Intellectual Capital Disclosure in Sustainability Reports
Authors: Bronzetti Giovanni , Mazzotta Romilda , Sicoli Graziella , Baldini Maria Assunta
Published: February 2013

The purpose of this chapter is to analyze the level and the quality of voluntary disclosures of Intellectual Capital (IC) in the sustainability reports on a sample of Italian listed companies. The authors conducted an analysis of twelve sustainability reports for two years (2009-2010). These are related to six firms selected among the most capitalized 37 Italian listed companies. To investigate the “level of disclosure,” the authors identified the presence of IC information, while to evaluate the “IC quality,” they constructed a voluntary disclosure index based on content analysis. IC information disclosure is more likely present in sustainability reports of firms with a higher levels of application of the Global Reporting Initiative framework. The results confirm that the sustainability report can adequately represent the intellectual capital, especially in order to understand its role in the firm and the interaction with other variables present in the firm.
Understanding the Role of Instructional Video in Higher Education Settings
Authors: Sugar William
Published: February 2013

An instructional designer, Susan Flanagan, who was recently hired (approximately three months ago) at Mount Lee Community College, helped the Social Sciences Division faculty members in creating online modules and classes for future semesters. As might be expected, several instructors were reluctant and resistant to teaching their respective courses online. Based on instructional design analyses, Susan identified that “lack of interaction” was the main concern of the resistant Social Sciences faculty members. Based on her findings, Susan convinced 80% of the Social Sciences faculty to incorporate one-minute video introductions into their respective online courses. As a result, Susan is now tasked with making a recommendation to an upcoming joint committee meeting of the Academic Core Standards committee and the Board of Trustees on instructional design best practices for a variety of video technologies.
The Inflammatory Twitch as a General Strategy for Controlling the Host Response
Authors: Pothen Joshua J. , Poynter Matthew E. , Bates Jason H. T.
Published: February 2013

Allergic inflammation is a general host-defense mechanism for dealing with perceived foreign invaders. Although most effort has been directed toward understanding how this response gets turned on, how it gets turned off again when no longer needed is just as important to an organism’s survival. We postulate that the control of the allergic inflammatory response is achieved via frequency modulation whereby a sequence of self-resolving events is repetitively invoked only so long as Ag is present. This leads to the notion of a unitary inflammatory event that we argue has formal similarity to the skeletal muscle twitch, albeit manifest over a much longer time scale. To test the plausibility of this hypothesis, we created an agent-based computational model of the allergic inflammatory response in the lungs. Continual stimulation of the model results in cycles of tissue damage and repair interspersed with periods of nonresponsiveness indicative of a refractory period. These findings are consistent with the inflammatory twitch hypothesis and the notion that the allergic inflammatory response is controlled via frequency modulation. We speculate that chronic inflammatory diseases may represent a failure of the inflammatory twitch to resolve toward baseline.
Pauci ex tanto numero: reducing redundancy in multi-model ensembles
Authors: Solazzo E. , Riccio A. , Kioutsioukis I. , Galmarini S.
Published: February 2013

Abstract. We explicitly address the fundamental issue of member diversity in multi-model ensembles. To date no attempts in this direction are documented within the air quality (AQ) community, although the extensive use of ensembles in this field. Common biases and redundancy are the two issues directly deriving from lack of independence, undermining the significance of a multi-model ensemble, and are the subject of this study. Shared biases among models will determine a biased ensemble, making therefore essential the errors of the ensemble members to be independent so that bias can cancel out. Redundancy derives from having too large a portion of common variance among the members of the ensemble, producing overconfidence in the predictions and underestimation of the uncertainty. The two issues of common biases and redundancy are analysed in detail using the AQMEII ensemble of AQ model results for four air pollutants in two European regions. We show that models share large portions of bias and variance, extending well beyond those induced by common inputs. We make use of several techniques to further show that subsets of models can explain the same amount of variance as the full ensemble with the advantage of being poorly correlated. Selecting the members for generating skilful, non-redundant ensembles from such subsets proved, however, non-trivial. We propose and discuss various methods of member selection and rate the ensemble performance they produce. In most cases, the full ensemble is outscored by the reduced ones. We conclude that, although independence of outputs may not always guarantee enhancement of scores (but this depends upon the skill being investigated) we discourage selecting the members of the ensemble simply on the basis of scores, that is, independence and skills need to be considered disjointly.
An unknown oxidative metabolism substantially contributes to soil CO2 emissions
Authors: Maire V. , Alvarez G. , Colombet J. , Comby A. , Despinasse R. , Dubreucq E. , Joly M. , Lehours A.-C. , Perrier V. , Shahzad T. , Fontaine S.
Published: February 2013

Abstract. The respiratory release of CO2 from soils is a major determinant of the global carbon cycle. It is traditionally considered that this respiration is an intracellular metabolism consisting of complex biochemical reactions carried out by numerous enzymes and co-factors. Here we show that the endoenzymes released from dead organisms are stabilised in soils and have access to suitable substrates and co-factors to permit function. These enzymes reconstitute an extracellular oxidative metabolism (EXOMET) that may substantially contribute to soil respiration (16 to 48% of CO2 released from soils in the present study). EXOMET and respiration from living organisms should be considered separately when studying effects of environmental factors on the C cycle because EXOMET shows specific properties such as resistance to high temperature and toxic compounds.
Influence of basin connectivity on sediment source, transport, and storage within the Mkabela Basin, South Africa
Authors: Miller J. R. , Mackin G. , Lechler P. , Lord M. , Lorentz S.
Published: February 2013

Abstract. The management of sediment and other non-point source (NPS) pollution has proven difficult, and requires a sound understanding of particle movement through the drainage system. The primary objective of this investigation was to obtain an understanding of NPS sediment source(s), transport, and storage within the Mkabela Basin, a representative agricultural catchment within the KwaZulu–Natal Midlands of eastern South Africa, by combining geomorphic, hydrologic and geochemical fingerprinting analyses. The Mkabela Basin can be subdivided into three distinct subcatchments that differ in their ability to transport and store sediment along the axial valley. Headwater (upper catchment) areas are characterized by extensive wetlands that act as significant sediment sinks. Mid-catchment areas, characterized by higher relief and valley gradients, exhibit few wetlands, but rather are dominated by a combination of alluvial and bedrock channels that are conducive to sediment transport. The lower catchment exhibits a low-gradient alluvial channel that is boarded by extensive riparian wetlands that accumulate large quantities of sediment (and NPS pollutants). Fingerprinting studies suggest that silt- and clay-rich layers found within wetland and reservoir deposits of the upper and upper-mid subcatchments are derived from the erosion of fine-grained, valley bottom soils frequently utilized as vegetable fields. Coarser-grained deposits within these wetlands and reservoirs result from the erosion of sandier hillslope soils extensively utilized for sugar cane, during relatively high magnitude runoff events that are capable of transporting sand-sized sediment off the slopes. Thus, the source of sediment to the axial valley varies as a function of sediment size and runoff magnitude. Sediment export from upper to lower catchment areas was limited until the early 1990s, in part because the upper catchment wetlands were hydrologically disconnected from lower parts of the watershed during low to moderate flood events. The construction of a drainage ditch through a previously unchanneled wetland altered the hydrologic connectivity of the catchment, allowing sediment to be transported from the headwaters to the lower basin where much of it was deposited within riparian wetlands. The axial drainage system is now geomorphically and hydrologically connected during events capable of overflowing dams located throughout the study basin. The study indicates that increased valley connectivity partly negated the positive benefits of controlling sediment/nutrient exports from the catchment by means of upland based, best management practices.
Studies with Enamines: Route to Aminoazolopyrimidines and Arylazoazolopyrimidines
Authors: Salaheldin Abdellatif M. , Khairou Khalid S.
Published: February 2013

An easy preparation of enaminonitrile derivatives and their transformation into new substituted azolopyrimidines is described. The one-step transformation was carried out under microwave irradiation and by classical heating methods. The use of microwave irradiation led to high conversion and shorter reaction times.
New Crystalline Forms of Piroxicam
Authors: Mishnev Anatoly , Kiselovs Glebs
Published: February 2013

Four new crystalline forms of piroxicam have been obtained and studied by single-crystal X-ray structure analysis. These comprise an addition salt with hydrochloric acid, acetic and isobutyric acids solvates, as well as piroxicam and furosemide cocrystal acetone solvate. All these new structures contribute to the variety of already known piroxicam crystalline forms. The analysis of conformations and tautomeric forms of piroxicam molecules in different crystal forms is presented.
A Novel 2D Mn(II) Coordination Polymer Based on the New Flexible 3-Carboxy-1-(4'-(2''-carboxy)biphenylmethyl)-2-oxidopyridinium and the Pyrazino[2,3-f][1,10]phenanthroline Ligands
Authors: Qiao Qian , Yu Xiao-Min , Wang Yuan-Rui , Li Zhen-Yu
Published: February 2013

A novel 2D coordination polymer, [Mn(pyphen)(L)] (1) (L=3-carboxy-1-(4'-(2''- carboxy)biphenylmethyl)-2-oxidopyridinium and pyphen=pyrazino[2,3- f ][1,10]phenanthroline), has been synthesized under hydrothermal conditions, and characterized by elemental analysis, IR, UV/Vis spectra and its optical band gap. Crystal data for 1: C34H21MnN5O5, monoclinic, space group P21/c, a=12.484(4), b=13.473(5), c=16.479(3) Å, b =99.618(6)° , V =2732.8(14) Å3, Z =4. In 1, each L ligand coordinates to three Mn(II) atoms through its two carboxylate groups and one phenolate unit. In this way, L2- ligands link neighboring Mn(II) atoms to generate a layer structure.
Corporate Social Responsibility and Horizontal Differentiation in Imperfect Competitive Markets with Global Warming Effects
Authors: Barboza Gustavo , Trejos Sandra
Published: February 2013

Abstract: This study develops a model of corporate social responsibility (CSR) behavior that is compatible with both the mutual goals of profit maximization and the reduction of global warming effects. The theory developed in this paper indicates that, under perfect competitive and unregulated markets, firms must take an innovative entrepreneurship approach to reduce global warming externalities, and, consequently, respond to the demands of stakeholders to behave in a CSR fashion. In this setting, managers and firms find incentives to pursue strategies leading to horizontal differentiation when a segment of the market has strong revealed consumption preferences for environmentally friendly products, and when consumers derive a consumption disutility from products creating global warming effects. To achieve these goals, firms using a safe technology also incur certification/labeling costs in order to gain market power. That is, this study demonstrates that, in unregulated competitive markets, efforts to clearly identify sources of global warming effects require innovative entrepreneurship thinking above and beyond government regulatory efforts. Thus, firms behaving in a CSR fashion may achieve monopolistic power, and therefore positive profits. In sum, our model demonstrates that CSR is compatible with the triple bottom line of economic, social and environmental performance.
Développer la créativité par la conception d’un objet à réaliser. Mise en place d’un dispositif de Learning Study dans la formation des enseignants
Authors: Leuba Denis , Didier John , Perrin Nicolas , Puozzo Isabelle , Vanini de Carlo Katja
Published: February 2013

Cet article décrit, dans un premier temps, en quoi l’épistémologie de la discipline des activités créatrices et manuelles en Suisse francophone ne permet pas de développer la créativité. Dans un deuxième temps, il propose un modèle théorique innovant qui permet d’appréhender le processus de production d’un objet artisanal – tel qu’il peut être suivi par un élève dans le cadre de l’enseignement des activités créatrices et manuelles – comme une occasion de développer la créativité. Cette dernière est alors définie comme la capacité de réaliser une production qui soit à la fois nouvelle et adaptée au contexte dans lequel elle se manifeste. Les opérations cognitives induites par l’activité de conception de l’objet et de l’anticipation de sa socialisation entraînent l’élève à gérer une démarche créative contextualisée par un problème. Dans un troisième temps, cet article présente la façon dont une équipe de formateurs a eu recours à un dispositif de Learning Study pour favoriser l’appropriation de ce modèle par les enseignants. Différents obstacles didactiques sont alors identifiés, ce qui permet d’interroger en retour le modèle théorique.
Neptuno Alegórico: emblemático arco en la obra de sor Juana
Authors: Ruiz Facundo
Published: February 2013

ABSTRACT: Frequently but unevenly valued, sor Juana Inés de la Cruz’s (1648-1695) Neptuno alegórico [Allegorical Neptune] has received increased attention in recent years, as though —by virtue of its nature as «ephemeral art»— «that» art (emblematic) had become increasingly more meaningful than the fugacious situation from which it emerged. An exceptional text, the design of the triumphal archway that welcomed the new viceroy Tomás Antonio de la Cerda and his wife María Luisa Manrique de Lara in 1680, reveals not only the importance that sor Juana had already attained, to a great extent, as a writer, but also, and more emphatically, it shows the relevance of her public figure and, in a programatic sense, demonstrates a certain matrix for her literature. Therefore, this study seeks to analyze the Neptuno alegórico in depth in order to reveal the three passages manifested in it: the one that converts the author into a (problematically) public figure; the one that displays in such an erudite and artistic manner a certain way of conceiving and practicing literary writing in the public sphere; and, finally, the one that places «that» literature (by Sor Juana) on a «gilded» map of Hispano-American literature. KEY WORDS: sor Juana, Neptuno alegórico, Ttriumphal Arch, Ephemeral Art, Baroque  RESUMEN: Histórica pero desigualmente valorado, el Neptuno Alegórico de sor Juana Inés de la Cruz (México, 1648-1695) ha recibido en los últimos años una atención creciente, como si —en su carácter de «arte efímero»— tuviera cada vez más sentido «ese» arte (emblemático) que la fugacidad (coyuntural) que lo motivó. Texto singular, el diseño del arco triunfal que recibió en 1680 al nuevo virrey Tomás Antonio de la Cerda y a su esposa, María Luisa Manrique de Lara, pone en evidencia no sólo la importancia de la escritora que ya era —en buena medida— sor Juana sino, más enfáticamente, la relevancia de su figura pública y, de forma programática, cierta matriz para su literatura. En este sentido, el presente trabajo se propone analizar detenidamente dicho texto a fin de concebir el pasaje triple allí manifiesto: el que convierte a esa escritora en una figura (problemáticamente) pública; el que exhibe tan erudita como artísticamente cierta forma de hacer y pensar la escritura literaria en el espacio público; y, finalmente, el que coloca «esa» literatura (sorjuanina) en un «áureo» mapa literario hispanoamericano. PALABRAS CLAVES: sor Juana, Neptuno alegórico, arco triunfal, arte efímero, barroco
«O engenho e a arte» de Camões nos emblemas das Festas que se fizeram pelo casamento del Rey D. Affonso VI
Authors: Gonçalves Medeiros Araújo Filipa Marisa
Published: February 2013

ABSTRACT: This study aims to offer an interpretation of the possible meanings of the emblematic images and verses of Camões present in the triumphal arches erected for the royal wedding of Afonso VI and Maria Francisca de Sabóia (1666), through the analysis of the epithalamic album entitled Festas que se fizerão pelo Cazamento del Rey D. Affonso VI. Its texts and symbolic watercolors are of great artistic and cultural interest, because they derive their inspiration from the emblem books of the period in order to disseminate political messages that can be read in multiple ways. KEY WORDS: Emblematics, Ephemeral Art, Marriage, Baroque Courts, Camões   RESUMEN: Este estudio pretende realizar una aproximación a los posibles significados de las imágenes emblemáticas y los versos camonianos presentes en los arcos del triunfo de las fiestas del matrimonio de Afonso VI de Portugal con Maria Francisca de Sabóia (1666), mediante el análisis del álbum epitalámico titulado Festas que se fizerão pelo Cazamento del Rey D. Affonso VI. Sus textos y acuarelas simbólicas son de gran interés artístico y cultural, pues se inspiran en las composiciones de los libros de emblemas del periodo para difundir mensajes políticos de doble lectura. PALABRAS CLAVES: emblemática, arte efímero, matrimonio, cortes barrocas, Camões
Women principals in South Africa: gender, mothering and leadership
Authors: Lumby Jacky , Azaola Marta Cristina
Published: February 2013

This paper draws on qualitative data from a mixed‐method study that analysed women's access to the principal role and their leadership experiences. The paper draws on a subset of interviews with 54 female head teachers in the Gauteng and North West provinces of South Africa. Since a mothering style of leadership was self‐reported by over half of the participants in our study, this paper aims to explore the diverse ways in which motherhood was constructed and the outcomes of these constructions on women.
A one-loop study of matching conditions for static-light flavor currents
Authors:   The ALPHA collaboration, Hesse Dirk , Sommer Rainer
Published: February 2013

Abstract

Heavy Quark Effective Theory (HQET) computations of semi-leptonic decays, e.g. B → πlν, require the knowledge of the parameters in the effective theory for all components of the heavy-light flavor currents. So far non-perturbative matching conditions have been employed only for the time component of the axial current. Here we perform a check of matching conditions for the time component of the vector current and the spatial component of the axial vector current up to one-loop order of perturbation theory and to lowest order of the 1/m-expansion. We find that the proposed observables have small higher order terms in the 1/m-series and are thus excellent candidates for a non-perturbative matching procedure.
Multi-Wavelength Studies of the GX 339-4 2010 outburst
Authors: Bel Marion Cadolle , Corbel S. , Veledina A. , Rodriguez J. , D'Avanzo P. , Tomsick J. , Russell D. M. , Lewis F.
Published: February 2013

The microquasar GX 339-4 experienced an outburst in 2010. We focus on observations that are quasi-simultaneous with those made by INTEGRAL and RXTE in March–April 2010 with radio, NIR, optical and UV data. X-ray transients are extreme systems, often harboring a black hole, known to emit throughout the whole electromagnetic spectrum in outburst. We studied the source evolution and correlated changes in all wavelengths. The bolometric flux increased from 0.8 to 2.9 × 10−8 erg cm−2 s−1 while the relative contribution of the hot medium decreased. The radio, NIR and optical emission from jets was detected and observed to fade as the source softened; reprocessing in the disc was strong at the end.
Feeding and Small-scale Feedback in Low-Luminosity AGNs
Authors: Shcherbakov Roman V. , Baganoff Frederick K. , Wong Ka-Wah , Irwin Jimmy
Published: February 2013

The unmatched X-ray resolution of Chandra allows probing the gas flow near quiescent supermassive black holes (BHs). The radius of BH gravitational influence on gas, called the Bondi radius, is resolved in Sgr A* and NGC 3115. Shallow accretion flow density profiles n ∝ r−β with β=0.7–1.0 were found for Sgr A* and NGC 3115 with the help of Chandra. We construct self-consistent models with gas feeding and dynamics from near the Bondi radius to the event horizon to explain the observations. Gas is mainly supplied to the region by hot colliding stellar winds. Small-scale feedback such as conduction effectively flattens the density profile from steep β=1.5 in a Bondi flow. We further constrain density and temperature profiles using the observed radio/sub-mm radiation emitted near the event horizon. We discuss the present state of our numerical model and its qualitative features, such as the role of the galactic gravitational potential and the random motion of wind-emitting stars.
The criteria for dynamical mass transfer of the main-sequence donor stars
Authors: Ge H. , Webbink R. F. , Chen X. , Han Z.
Published: February 2013

Mass transfer is very common in binary evolution and it dominates the evolutionary fate of binaries. Two crucial problems i.e. dynamical mass transfer and common envelope evolution, are not well understood yet. Here we focus on the first problem, and systematically show the critical mass ratio for dynamical mass transfer when the donor stars are still on the main sequence (MS).
Problems of Clustering of Radiogalaxies
Authors: Godłowski Włodzimierz , Pollo Agnieszka , Golbiak Jacek
Published: February 2013

We present the preliminary analysis of clustering of a sample of 1157 radio-identified galaxies from Machalski & Condon (1999). We found that for separations 2–15 h−1 Mpc their redshift space autocorrelation function ξ(s) can be approximated by the power law with the correlation length ~3.75h−1 Mpc and slope γ ~ 1.8. The correlation length for radiogalaxies is found to be lower and the slope steeper than the corresponding parameters of the control sample of optically observed galaxies. Analysis the projected correlation function Ξ(r) displays possible differences in the clustering properties between active galactic nuclei (AGN) and starburst (SB) galaxies.
The emission lines radiated from accretion disk in cataclysmic variables
Authors: He L. , Zhao Y. H. , Lv G. L.
Published: February 2013

During the quiescent phases, the spectra of cataclysmic variables are studied. We model the fluxes by means of the photoionization code CLOUDY, and in the model it is assumed that the geometry of disks is cylindrical. Using this method, we input a series of reasonable parameters and get a spectral library.
The lifetime of contact binaries
Authors: Jiang D. K. , Han Z. W. , Yang L. H. , Li L. F.
Published: February 2013

The lifetime of contact binaries is an important parameter for studying the evolution of contact binaries. By reproducing the relative frequency of occurrence for contact binaries, we found that the lifetime of contact binaries decreases with increasing mass of the primaries. The lifetime of contact binaries is about 4%–10% of the main sequence lifetime of the primaries, and is about 0.006–0.65 Gyr. This suggests that the lifetime of contact binaries strongly depends on the mass of the primaries.
Optical Afterglows as Probes for the Central Engine and Fireball of Gamma-Ray Bursts
Authors: Li Liang , Liang En-Wei , Gao He , Zhang Bing
Published: February 2013

Well-sampled optical lightcurves of 146 gamma-ray bursts (GRBs) are compiled from literature. We identify possible emission components based on our empirical fits and present statistical analysis for these components. We find that the flares are related to prompt emission, suggesting that they could have the same origin in different episodes. The shallow decay segment is not correlated with prompt gamma-rays. It likely signals a long-lasting injected wind from GRB central engines. Early after onset peak is closely related with prompt emission. The ambient medium density profile is likely n ∝ r−1. No correlation between the late re-brightening bump and prompt gamma-rays or the onset bump is found. They may be from another jet component.
AGN-host galaxy connection: multiwavelength study
Authors: Pović M. , Sánchez-Portal M. , García A. M. Pérez , Bongiovanni A. , Cepa J. ,   OTELO team
Published: February 2013

The connection between active galactic nuclei (AGN) and their hosts showed to be important for understanding the formation and evolution of active galaxies. Using X–ray and deep optical data, we study how morphology and colours are related to X–ray properties at redshifts z≤2.0 for a sample of > 300 X–ray detected AGN in the Subaru/XMM-Newton Deep Survey (SXDS; Furusawa et al. 2008) and Groth-Westphal Strip (GWS; Pović et al. 2009) fields. We performed our morphological classification using the galSVM code (Huertas-Company et al. 2008), which is a new method that is particularly suited when dealing with high-redshift sources. To separate objects between X–ray unobscured and obscured, we used X–ray hardness ratio HR(0.5-2 keV/2-4.5 keV). Colour-magnitude diagrams were studied in relationship to redshift, morphology, X–ray obscuration, and X–ray-to-optical flux ratio. Around 50% of X–ray detected AGN at z≤2.0 analysed in this work reside in spheroidal and bulge-dominated galaxies, while at least 18% have disk-dominated hosts. This suggests that different mechanisms may be responsible for triggering the nuclear activity. When analysing populations of X–ray detected AGN in both colour-magnitude (CMD) and colour-stellar mass diagrams (Figure 1), the highest number of sources is found to reside in the green valley at redshifts ≈ 0.5–1.5. For the first time we studied CMD of these AGN in relation to morphology and X–ray obscuration, finding that they can reside in both early- and late-type hosts, where both morphological types cover similar ranges of X–ray obscuration (Figure 1). Our findings appear to confirm some previous suggestions that X–ray selected AGN residing in the green valley represent a transitional population (e.g. Nandra et al. 2007, Silverman et al. 2008, Treister et al. 2009), quenching star formation by means of different AGN feedback mechanisms and evolving to red-sequence galaxies. More details on analysis and results presented here can be found in Pović et al. 2012.
Direct production of mouse disease models by embryo microinjection of TALENs and oligodeoxynucleotides
Authors: Wefers Benedikt , Meyer Melanie , Ortiz Oskar , Hrabé de Angelis Martin , Hansen Jens , Wurst Wolfgang , Kühn Ralf
Published: February 2013

The study of genetic disease mechanisms relies mostly on targeted mouse mutants that are derived from engineered embryonic stem (ES) cells. Nevertheless, the establishment of mutant ES cells is laborious and time-consuming, restricting the study of the increasing number of human disease mutations discovered by high-throughput genomic analysis. Here, we present an advanced approach for the production of mouse disease models by microinjection of transcription activator-like effector nucleases (TALENs) and synthetic oligodeoxynucleotides into one-cell embryos. Within 2 d of embryo injection, we created and correctedchocolatemissense mutations in the small GTPase RAB38; a regulator of intracellular vesicle trafficking and phenotypic model of Hermansky-Pudlak syndrome. Because ES cell cultures and targeting vectors are not required, this technology enables instant germline modifications, making heterozygous mutants available within 18 wk. The key features of direct mutagenesis by TALENs and oligodeoxynucleotides, minimal effort and high speed, catalyze the generation of future in vivo models for the study of human disease mechanisms and interventions.
Host Range of Fusarium Dieback and Its Ambrosia Beetle (Coleoptera: Scolytinae) Vector in Southern California
Authors: Eskalen Akif , Stouthamer Richard , Lynch Shannon Colleen , Rugman-Jones Paul F. , Twizeyimana Mathias , Gonzalez Alex , Thibault Tim
Published: February 2013

The polyphagous shot hole borer (PSHB) is an invasive ambrosia beetle that forms a symbiosis with a new, as-yet-undescribed Fusarium sp., together causing Fusarium dieback on avocado and other host plants in California and Israel. In California, PSHB was first reported on black locust in 2003 but there were no records of fungal damage until 2012, when a Fusarium sp. was recovered from the tissues of several backyard avocado trees infested with PSHB in Los Angeles County. The aim of this study was to determine the plant host range of the beetle–fungus complex in two heavily infested botanical gardens in Los Angeles County. Of the 335 tree species observed, 207 (62%), representing 58 plant families, showed signs and symptoms consistent with attack by PSHB. The Fusarium sp. was recovered from 54% of the plant species attacked by PSHB, indicated by the presence of the Fusarium sp. at least at the site of the entry hole. Trees attacked by PSHB included 11 species of California natives, 13 agriculturally important species, and many common street trees. Survey results also revealed 19 tree species that function as reproductive hosts for PSHB. Additionally, approximately a quarter of all tree individuals planted along the streets of southern California belong to a species classified as a reproductive host. These data suggest the beetle–disease complex potentially may establish in a variety of plant communities locally and worldwide.
Method to obtain hybrid rapid tools with elementary component assembly
Authors: Rivette M. , Mognol P. , Hascoet J.Y.
Published: February 2013

Purpose

The purpose of this paper is to propose a method to obtain hybrid rapid tools with elementary component assembly.

Design/methodology/approach

The authors' method proposes a functional representational model, starting with the product features, analyzed from three points of view: a feasibility analysis; a manufacturing analysis; and an assembly and synthesis analysis. This method, based on CAD STEP AP‐224 data, makes it possible to obtain an exhaustive list of solutions for the module. The work is illustrated with an industrial example. To construct the Assembly Identity Card (AIC) and test the various parameters that influence the quality of the injected parts, a hybrid injection mold has been produced. The methodology associated with the use of this AIC uses a “representation graph”, which makes it possible to propose a set of valid solutions for assembling the various tooling modules. This method is validated by industrial example.

Findings

The product part is decomposed into a multi‐component prototype (MCP), instead of being made as a single part, which optimizes the manufacturing process and enables greater reactivity during the development of the product.

Research limitations/implications

The final goal is to propose a software assistant used in association with CAD system during the design of hybrid rapid tooling. An important work concerning the features recognition must be implemented. The assembly of the different parts of the hybrid rapid tooling must be considered and optimized.

Practical implications

This method allows the selection of the best process technologies from manufacturing tools.

Originality/value

The analysis of manufacturing hybrid rapid tooling has not been studied previously.
An analysis view on password patterns of Chinese internet users
Authors: Yang Cheng , Hung Jui‐long , Lin Zhangxi
Published: February 2013

Purpose

In December 2011, the National Computer Network Emergency Response Technical Team/Coordination Center of China reported the most serious user data leak in history which involved 26 databases with 278 million user accounts and passwords. After acquiring the user data from this massive information leak, this study has two major research purposes: the paper aims to reveal similarities and differences of password construction among four companies; and investigate how culture factors shape user password construction in China.

Design/methodology/approach

This article analyzed real‐life passwords collected from four companies by comparing the following attributes: password length, password constitution, top 20 frequent passwords, character frequency distributions, string similarity, and password reuse.

Findings

Major findings include that: general users in China have a weaker sense of security than those in Western countries, which reflected in the password lengths, the character combinations and the content structures; password constitution preferences are different between users in Western countries and in China, where passwords are more similar to the Pinyin context and Chinese number homonym; and password reuse is very common in China. General users tend to reuse the same passwords and IT professionals tend to engage in Seed Password reuse.

Research limitations/implications

Due to the rapid growth of Internet users and e‐commerce markets in China, many online service providers may not pay enough attention to security issues, but focus instead on market expansion. Employees in these companies may not be well trained in information security, resulting in carelessness when handling security issues.

Originality/value

This is the first study which attempts to consider culture influences in password construction by analyzing real‐life datasets.
Nutrition products for preterm infants: Do they meet requirements? Discoveries from the infant enteral feeding tender
Authors: Gilroy Melissa , Page Denise
Published: February 2013

Aim

The objectives of the present study were to determine if products marketed for preterm and term infants in 2009 met the recommendations for these groups, and to review macronutrient, micronutrient and product specifications through the development of a novel and robust approach to the clinical nutrition component of the infant feeding tender.

Methods

Tender applicants were requested to provide information in a standardised format to allow product comparison. In total, 28 macronutrients and micronutrients for each formulation were tabulated and compared at standard feeding volumes with reasonable nutrient intakes for preterm infants and nutrient reference values for term infants. In addition, other product specifications were considered with current evidence. A weighing system was developed; meeting essential clinical nutrient requirements contributed a possible 80% and other product specifications, including desirable clinical requirements, contributed a possible 20% of the total score.

Results

Nutrition products marketed for preterm infants varied in their ability to meet the reasonable nutrient intakes at usual intake volumes. All products tendered for the term infant category met the nutrient reference values at usual intake volumes.

Conclusion

It cannot be assumed that products marketed for particular patient groups, such as preterm and term infants, meet the recommendations for that group. A review of enteral products addressing more than macronutrients and product specifications should be applied by all hospitals undergoing a feeding tender process for any patient group.