bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of generation current on the evaluation of the depletion width in heavily irradiated Si detectors
Authors: Gaubas E. , Čeponis T. , Vaitkus J.
Published: August 2011

The depletion width and full depletion condition are essential parameters in the search for radiation tolerant detector design and operational regimes. In this work, results of measurements of barrier capacitance by combining a transient technique for barrier evaluation by linearly increasing voltage (BELIV), with temperature dependent capacitance-voltage and current-voltage characteristics of neutron irradiated Si pin detectors are discussed. It is shown that the generation current, caused by a high density of radiation induced traps, distorts the capacitance measurements in heavily irradiated devices. There is no space charge sign inversion effect, however, and heavily irradiated detectors become fully depleted in equilibrium.
Higher order Darboux transformations in two dimensions, linearizable auxiliary equations, and invariant potentials
Authors: Schulze-Halberg Axel
Published: August 2011

We show that the two-dimensional Schrödinger equation admits Darboux transformations only for a particular class of potentials. It is demonstrated that for such potentials, the associated auxiliary equation can be linearized to Schrödinger form. Furthermore, since the aforehand mentioned class of potentials turns out to remain invariant under Darboux transformations, construction of multiple, higher order Darboux transformations (chains) becomes possible. We present second-order chains in explicit form and give an algorithmic scheme for the construction of higher order chains.
Solar radiation shielding material for windows TiN studied from first-principles theory
Authors: Xiao Lihua , Su Yuchang , Chen Hongyang , Liu Sainan , Jiang Min , Peng Ping , Liu Sidong
Published: August 2011

Using first-principles calculations in the framework of density functional theory, we studied the electronic structure and optical performance of TiN. It was found that the calculated structure parameter and optical performance are in better agreement with the latest relevant experimental data, and our theoretical studies showed that TiN is a perfect near infrared absorber with high visible light transmittance and could serve as references for future experimental study and its applications as solar radiation shielding material for windows.
NetDS: a Cytoscape plugin to analyze the robustness of dynamics and feedforward/feedback loop structures of biological networks
Authors: Le Duc-Hau , Kwon Yung-Keun
Published: August 2011

Summary: NetDS is a novel Cytoscape plugin that conveniently simulates dynamics related to robustness, and examines structural properties with respect to feedforward/feedback loops. It can evaluate how robustly a network sustains a stable state against mutations by employing a Boolean network model. In addition, the plugin can examine all feedforward/feedback loops appearing in a network and determine whether or not a pair of loops is coupled. Random networks can also be generated to evaluate whether or not an interesting finding in real biological networks is significantly random.

Availability: NetDS is freely available for non-commercial purposes at http://netds.sourceforge.net/.

Contact:  kwonyk@ulsan.ac.kr

Supplementary information:  Supplementary data are available at Bioinformatics online.
Effect of Crop Rotations on Rotylenchulus reniformis Population Structure
Authors: Leach Megan , Agudelo Paula , Lawton-Rauh Amy
Published: August 2011

Rotylenchulus reniformis is a highly variable nematode species and an economically important pest in many cotton fields across the south-eastern United States. Rotation with resistant or poor host crops is a method for management of reniform nematode. We studied the effect of six planting schemes covering four 120-day planting cycles on the predominant genotype of R. reniformis. Rotations used were: (i) cotton to corn; (ii) susceptible soybean to corn; (iii) resistant soybean to cotton; (iv) corn to cotton; (v) continuous susceptible soybean; (vi) continuous cotton. After each 120-day cycle, amplified fragment length polymorphisms (AFLPs) produced from four primer pairs were used to determine the effect of crop rotation on the predominant genotype of reniform nematode. A total of 279 polymorphic bands were scored using four primer combinations. Distinct changes in genotype composition were observed following rotations with resistant soybean or corn. Rotations involving soybean (susceptible and resistant) had the greatest effect on population structure. The characterization of field population variability of reniform nematode and of population responses to host plants used in rotations can help extend the durability of resistant varieties and can help identify effective rotation schemes.
The indentation of pressurized elastic shells: from polymeric capsules to yeast cells
Authors: Vella Dominic , Ajdari Amin , Vaziri Ashkan , Boudaoud Arezki
Published: August 2011

Pressurized elastic capsules arise at scales ranging from the 10 m diameter pressure vessels used to store propane at oil refineries to the microscopic polymeric capsules that may be used in drug delivery. Nature also makes extensive use of pressurized elastic capsules: plant cells, bacteria and fungi have stiff walls, which are subject to an internal turgor pressure. Here, we present theoretical, numerical and experimental investigations of the indentation of a linearly elastic shell subject to a constant internal pressure. We show that, unlike unpressurized shells, the relationship between force and displacement demonstrates two linear regimes. We determine analytical expressions for the effective stiffness in each of these regimes in terms of the material properties of the shell and the pressure difference. As a consequence, a single indentation experiment over a range of displacements may be used as a simple assay to determine both the internal pressure and elastic properties of capsules. Our results are relevant for determining the internal pressure in bacterial, fungal or plant cells. As an illustration of this, we apply our results to recent measurements of the stiffness of baker's yeast and infer from these experiments that the internal osmotic pressure of yeast cells may be regulated in response to changes in the osmotic pressure of the external medium.
Trapping of water waves by freely floating structures in a channel
Authors: Nazarov Sergey A. , Videman Juha H.
Published: August 2011

This article is concerned with the existence of rigid freely floating structures capable of supporting trapped modes (time-harmonic water waves of finite energy in an unbounded domain). Under the usual assumptions of linear water-wave theory, a condition guaranteeing the existence of trapped modes is derived, and structures satisfying this geometric condition are shown to exist in a three-dimensional water channel. The sufficient condition arises from the application of variational principles to a conveniently formulated linear spectral problem, the main effort being the construction of a reduction scheme that turns the quadnic operator pencil associated with the original coupled system into a linear self-adjoint spectral problem. An example of floating bodies supporting at least four trapped modes is given.
Trends in adolescent alcohol use: effects of age, sex and cohort on prevalence and heritability
Authors: Geels Lot M. , Bartels Meike , van Beijsterveldt Toos C. E. M. , Willemsen Gonneke , van der Aa Niels , Boomsma Dorret I. , Vink Jacqueline M.
Published: August 2011

Aims  To determine the effect of age, sex and cohort on the prevalence and genetic architecture of adolescent alcohol use (AAU).

Design  Survey study in participants registered with the Netherlands Twin Register.

Setting  Twins from the general population.

Participants  Two cohorts (data collected in 1993 and 2005–08) of twins aged 13–15, 16–17 and 18–21 years. In 1993 and 2005–08 a total of 3269 and 8207 twins, respectively, took part.

Measurements  Survey data on initiation and frequency of alcohol use and quantity of alcohol consumed.

Findings  The prevalence of alcohol initiation increased between 1993 and 2005–08 for both males and females. The largest difference was for girls observed at ages 13–15, where the prevalence increased from 59.5% to 72.4%. We also found increases in prevalence across cohorts for quantity of alcohol consumed and non‐significant increases for frequency of alcohol use. From age 16 onwards, boys drank more frequently and larger quantities than girls. Genetic model fitting revealed that the genetic architecture of AAU did not differ between birth cohorts, nor were there differences between boys and girls. Genetic factors explained between 21% and 55% of individual differences in alcohol measures throughout adolescence. Shared environment explained between 17% and 64% of variance in alcohol use, across different age groups and alcohol measures.

Conclusions  In the Netherlands, the prevalence of alcohol initiation, frequency and quantity has increased in adolescents over a 15‐year period, but there are no changes in the genetic architecture of adolescent alcohol use.
Ingredients for protist coexistence: competition, endosymbiosis and a pinch of biochemical interactions
Authors: Müller Johann P. , Hauzy Céline , Hulot Florence D.
Published: August 2011

1. The interaction between mutualism, facilitation or interference and exploitation competition is of major interest as it may govern species coexistence. However, the interplay of these mechanisms has received little attention. This issue dates back to Gause, who experimentally explored competition using protists as a model [Gause, G.F. (1935) Vérifications expérimentales de la théorie mathématique de la lutte pour la vie. Actualités Scientifiques et Industrielles, 277]. He showed the coexistence of Paramecium caudatum with a potentially allelopathic species, Paramecium bursaria.

2. Paramecium bursaria hosts the green algae Chlorella vulgaris. Therefore, P. bursaria may benefit from carbohydrates synthesised by the algae. Studying endosymbiosis with P. bursaria is possible as it can be freed of its endosymbiont. In addition, C. vulgaris is known to produce allelochemicals, and P. bursaria may benefit also from allelopathic compounds.

3. We designed an experiment to separate the effects of resource exploitation, endosymbiosis and allelopathy and to assess their relative importance for the coexistence of P. bursaria with a competitor that exploits the same resource, bacteria. The experiment was repeated with two competitors, Colpidium striatum or Tetrahymena pyriformis.

4. Results show that the presence of the endosymbiont enables the coexistence of competitors, while its loss leads to competitive exclusion. These results are in agreement with predictions based on resource equilibrium density of monocultures (R*) supporting the idea that P. bursaria’s endosymbiont is a resource provider for its host. When P. bursaria and T. pyriformis coexist, the density of the latter shows large variation that match the effects of culture medium of P. bursaria. Our experiment suggests these effects are because of biochemicals produced in P. bursaria culture.

5. Our results expose the hidden diversity of mechanisms that underlie competitive interactions. They thus support Gauses’s speculation (1935) that allelopathic effects might have been involved in his competition experiments. We discuss how a species engaged both in competition for a resource and in costly interference such as allelopathy may counterbalance these costs with a resource‐provider endosymbiont.
Liver transplantation for severe hepatitis in patients with common variable immunodeficiency
Authors: Murakawa Yasuhiro , Miyagawa‐Hayashino Aya , Ogura Yasuhiro , Egawa Hiroto , Okamoto Shinya , Soejima Yuji , Kurosawa Manabu , Sumiyoshi Shinji , Uemoto Shinji , Haga Hironori
Published: August 2011

Murakawa Y, Miyagawa‐Hayashino A, Ogura Y, Egawa H, Okamoto S, Soejima Y, Kurosawa M, Sumiyoshi S, Uemoto S, Haga H. Liver transplantation for severe hepatitis in patients with common variable immunodeficiency.  Pediatr Transplantation 2011. © 2011 John Wiley & Sons A/S.

Abstract:  CVID is a heterogeneous group of primary immunodeficiency diseases characterized by hypogammaglobulinemia, recurrent bacterial infections, and frequent autoimmune manifestations. The post‐transplant course of liver transplant recipients with CVID is rarely described. We report two patients with CVID complicated by severe enteropathy who underwent living donor liver transplantation for liver failure because of severe hepatitis. The post‐transplant course was complicated by recurrent acute rejection, leading to ductopenic rejection in one and recurrent hepatitis in the other. We reviewed the tissue samples histologically and immunohistochemically. Native livers showed submassive hepatocyte necrosis in one and cirrhotic liver with active hepatitis in the other, both with infiltration of CD8+ T cells accompanied by endothelialitis and bile duct damage; the intestine contained increased numbers of intraepithelial CD8+ T cells with apoptosis of epithelial cells. The liver allograft exhibited acute rejection, with prominent CD8+ T cells infiltrating the bile duct or endothelium. In the allograft following the diagnosis of post‐transplant recurrent hepatitis, CD8+ T cells comprised the majority of infiltrating cells in portal areas spilling over into hepatic parenchyma. Our cases suggest that T cells contribute to the pathogenesis of CVID in native organs as well as allografts and may constitute evidence of T‐cell deregulation in the pathogenesis of CVID.
Successful management of pregnancy and delivery in a woman with multiple coronary stenoses of unknown cause
Authors: Nakajima Yoshiyuki , Masaoka Naoki , Tashiro Hidefumi , Chiba Junko , Sakai Masato
Published: August 2011

We describe the case of a 30‐year‐old primiparous woman who had multiple coronary stenoses of unknown cause, and discuss causes and risks in pregnancy in a patient with coronary stenoses and the management and outcome.

At 13 years of age, the patient was diagnosed as having multiple coronary stenoses and percutaneous transluminal coronary angioplasty was performed. At the age of 30, coronary arteriography demonstrated multiple severe stenoses. Her previous physician had permitted her to become pregnant. At 32 weeks’ gestation, due to uncontrollable uterine contractions, magnesium sulfate was administered. At 37 weeks’ gestation, a cesarean section was performed because of breech presentation, and she delivered a healthy female infant. During cesarean section, oxytocin was given at a slower rate. There has been no recurrence of cardiac events during and after pregnancy. Multiple coronary stenoses during pregnancy need a multidisciplinary approach.
A single‐centre experience of chemoradiotherapy for rectal cancer: is there potential for nonoperative management?
Authors: Dalton R. S. J. , Velineni R. , Osborne M. E. , Thomas R. , Harries S. , Gee A. S. , Daniels I. R.
Published: August 2011

Aim  The aim of the study was to assess the outcome of patients who received chemoradiotherapy (CRT) for locally advanced rectal cancer, specifically those with complete clinical response (CCR) and who were then managed nonoperatively with a ‘Watch and Wait’ follow‐up protocol.

Method  A retrospective study was carried out of patients undergoing preoperative CRT for rectal cancer, conducted in a district general hospital managing rectal cancer through the multidisciplinary team process.

Results  Forty‐nine patients received preoperative CRT over a 5‐year period (2004–2009). Twelve (24%) were considered potentially to have had a complete response on MRI. Of these, six subsequently had clinical evidence of residual disease, leading to surgery (mean time to surgery, 24 weeks; range, 12–36 weeks). The remaining six had CCR, avoiding surgery (mean follow up, 26 months; range, 12–45 months), with all six patients disease free to date. A further six patients had complete pathological response (CPR) following surgery after comprehensive histopathological assessment of the specimen.

Conclusion  In this consecutive series of patients with locally advanced rectal cancer treated with CRT, 12% demonstrated a CCR and have been actively managed conservatively, thereby avoiding surgery. With further improvements in diagnostic assessment of response to CRT, this figure may rise.
Traumatic injury to the colon and rectum in Scotland: demographics and outcome
Authors: Brady R. R. , O’Neill S. , Berry O. , Kerssens J. J. , Yalamarthi S. , Parks R. W.
Published: August 2011

Aim  An analysis of a multi‐centred database of trauma patients was performed.

Method  The study used data from a prospective multi‐centre trauma database containing details of 52 887 trauma patients admitted to participating Scottish Hospitals over an 11‐year period.

Results  Three hundred and forty (0.64%) of 52 887 trauma patients (284 male) with colorectal injuries were identified; 43.9% of colorectal injuries occurred following blunt trauma and 56.1% following penetrating injury. Patients in the latter group were younger, had less haemodynamic compromise and were less likely to die than those with blunt trauma (P < 0.01). The overall mortality rate was 25.6% and after rectal injury it was 21.2% (P > 0.05). Female gender, increased age, road traffic accidents and those admitted as a result of a blunt traumatic injury were associated with increased mortality. Age > 65 years (P = 0.01), increasing injury severity score (ISS) at presentation (P < 0.001), haemodynamic compromise (P = 0.045) and decreased Glasgow Coma Score (GCS) (P < 0.001) had the strongest independent associations with mortality.

Conclusion  Colorectal injury after trauma has a high morbidity. Clinical features associated with death allow stratification of mortality risk.
Quality of care in rectal cancer surgery. Exploring influencing factors in the West of Scotland
Authors: Nicholson G. A. , Morrison D. S. , Finlay I. G. , Diament R. H. , Horgan P. G. , Molloy R. G.
Published: August 2011

Aim  To assess variability in the proportions of types of major resection for rectal cancer throughout the west of Scotland (WoS) and ascertain factors explaining the variability.

Method  Retrospective cohort study of a regional population clinical audit database. This was linked to cancer registrations and death certificates in order that outcome analyses could be derived. Univariate and multivariate binary logistic regression analyses were used to explore determinants of survival.

Results  A total of 1574 patients met the inclusion criteria. The age range was from 22 to 97 years. The mean age was 67, median age 68 and the standard deviation was 11.5. The majority of patients (61%) were male. Unlike previous series, male patients and those with poorer socioeconomic circumstances (SEC) were no more likely to receive an abdominoperineal excision (APE) procedure for rectal cancer.

Conclusion  Variation exists in the west of Scotland regarding surgical treatment for rectal cancer. We found no difference in the type of procedure offered according to sex, intent of operation or socioeconomic circumstances with reference to APE and anterior resection (AR) for rectal cancer. We conclude therefore that our region provides an equitable service on grounds of sex and SEC. This demonstrates that an equitable surgical service has been provided for those suffering from rectal cancer. Circumferential margin postitivity was four times more likely in an APE than an AR for rectal cancer. This is not explained by age, stage, sex, socioeconomic circumstances (SEC), volume of surgery, intent of operation, type of admission or year of incidence.
Estimating the social welfare effects of New Zealand apple imports
Authors: Cook David C. , Carrasco Luis R. , Paini Dean R. , Fraser Rob W.
Published: August 2011

International trade of agricultural products not only generates wealth but is also responsible for the introduction of invasive pests beyond their natural range. Comprehensive bioeconomic modelling frameworks are increasingly needed to assist in the resolution of import access disputes. However, frameworks that combine welfare analysis attributable to trade and invasive species spread management are lacking. This study provides a demonstration of how a comprehensive economic framework, which takes into account both the gains from trade and the costs of invasive species outbreaks, can inform decision‐makers when making quarantine decisions. We develop a partial equilibrium trade model considering international trade and combine it with a stratified dispersal model for the spread and management of potential outbreaks of an invasive species. An empirical estimation is made of the economic welfare consequences for Australia of allowing quarantine‐restricted trade in New Zealand apples to take place. The results suggest the returns to Australian society from importing New Zealand apples are likely to be negative. The price differential between the landed product with SPS measures in place and the autarkic price is insufficient to outweigh the increase in expected damage resulting from increased fire blight risk. As a consequence, this empirical analysis does not support the opening up of this trade.
‘Food with a purpose’– Home Economics teachers' construction of food and home
Authors: Höijer Karin , Hjälmeskog Karin , Fjellström Christina
Published: August 2011

Food and home are central issues in the Home Economics curriculum. The aim of the present paper was to explore how Home Economics teachers make sense of and manage being teachers in this particular subject and how they talk about food and home. This was achieved by conducting four focus groups with 25 participants, 23 women and two men, all with experience from working as Home Economics teachers. Participants were recruited from all over Sweden through emails. The data analysis was conducted in three steps and was guided by social constructionist theory. The main findings were the themes of Home Economics as food with a purpose, teachers with a public health commission, the fostering teacher, tangible cooking and the deficient home. The results show that Home Economics is constructed as a site for ‘proper knowledge’ about food in relation to a ‘deficient home’. Food in Home Economics was thus constructed as having a purpose.
Conceptualizing the household as an object of study
Authors: Niehof Anke
Published: August 2011

The use of the term household and the theoretical and empirical meanings attached to it have undergone changes through time. When Home Economics was established as an academic field of study, the household became its primary unit of analysis. In Northern societies, the concept of family gradually began to occupy the limelight, and functions and aspects formerly attributed to the household in studies on the domestic domain began to feature in family studies. Against the backdrop of the second feminist wave and the emergence of consumer society and urban lifestyles, the household was increasingly treated as a unit of consumption only.

Such a narrow conceptualization of the household not only limits its application to certain types of societies but also obstructs our view on the ways in which people provide for their food and care needs, cope with deprivation and adversity, and leaves the important role women play in these processes under‐exposed. These arguments are developed on the basis of an analysis of the results of 12 recent (2002–2010) Wageningen University PhD research projects in different Asian and African countries. The concepts of family and home emerge in the analysis as well, but are seen as partly overlapping with the concept of household and subsumed under it. On the basis of the results of the analysis and the literature, the paper formulates conclusions about the importance of the household as a unit of analysis and the relevance of a field of study that focuses on households and the domestic domain.
Teacher perceptions of the contribution of Home Economics to sustainable development education: a cross‐cultural view
Authors: Dewhurst Yvonne , Pendergast Donna
Published: August 2011

This paper reports on the contribution of Home Economics to sustainable development education as part of the school curriculum for students aged 11–18 years in a number of cultural contexts. A survey was used to collect data from Home Economics teachers in Australia, Canada, Malta and Scotland to better understand the similarities and differences of Home Economics curriculum in these contexts, as it contributes to sustainable development education. The data reveal that the teachers in the study considered sustainable development to be an important issue, and the formal Home Economics curricula made significant contributions to the education of this topic. It is noted, however, that the field of sustainable development education has neglected studies of Home Economics education and its teachers' perceptions about sustainable development education, and this is reinforced by a lack of research generated from the Home Economics field. The researchers argue that this is an inhibiting factor affecting the capacity of schools to achieve sustainable development goals.
Influence of distorted electric field distribution on microstructure formation in the electrohydrodynamic patterning process
Authors: Tian Hongmiao , Shao Jinyou , Ding Yucheng , Li Xin , Li Xiangming , Liu Hongzhong
Published: August 2011

Electrohydrodynamic (EHD) patterning is a process for electrically duplicating a micrometer- or submicrometer-scale pattern of a template onto a thin polymer film on a substrate by applying an electric potential between the template and substrate as an electrode pair. Simulations of the electrohydrodynamic patterning process that have been reported have been based on a linear and analytical formulation assuming an ideal template shape and process setup for mathematical simplification. However, the EHD process, involving coupling of electrostatic and hydrodynamic fields, tends to be strongly nonlinear in practice. Consequently, even a small deviation (represented by nonuniformity in the height of template microstructures or nonuniform gap between template and polymer film, for example) can lead to deviation of the duplicated pattern from the pattern expected under ideal process conditions. This article presents a numerical method for simulating this electrically induced microstructuring process based on nonlinear EHD theory and arbitrary Lagrangian-Eulerian (ALE) finite element formulation. The dynamic evolution of the microstructure obtained for nonuniform height of the template pattern and a nonuniform gap between the template and polymer film shows that a small deviation tends to lead to considerable distortion in the electrical field during growth of the polymer pattern, resulting in irregularity in the duplicated microstructures. The numerical analysis also demonstrates how the polymer structure irregularity can be alleviated by reduced electric potential and reduced average gap between the template and polymer surface.
4D analysis of influence of patient movement and anatomy alteration on the quality of 3D U/S‐based prostate HDR brachytherapy treatment delivery
Authors: Milickovic Natasa , Mavroidis Panayiotis , Tselis Nikolaos , Nikolova Iliyana , Katsilieri Zaira , Kefala Vasiliki , Zamboglou Nikolaos , Baltas Dimos
Published: August 2011

Purpose:

Modern HDR brachytherapy treatment for prostate cancer based on the 3D ultrasound (U/S) plays increasingly important role. The purpose of this study is to investigate possible patient movement and anatomy alteration between the clinical image set acquisition, made after the needle implantation, and the patient irradiation and their influence on the quality of treatment.

Methods:

The authors used 3D U/S image sets and the corresponding treatment plans based on a 4D‐treatment planning procedure: plans of 25 patients are obtained right after the needle implantation (clinical plan is based on this 3D image set) and just before and after the treatment delivery. The authors notice the slight decrease of treatment quality with increase of time gap between the clinical image set acquisition and the patient irradiation. 4D analysis of dose‐volume‐histograms (DVHs) for prostate: CTV1 = PTV, and urethra, rectum, and bladder as organs at risk (OARs) and conformity index (COIN) is presented, demonstrating the effect of prostate, OARs, and needles displacement.

Results:

The authors show that in the case that the patient body movement/anatomy alteration takes place, this results in modification of DVHs and radiobiological parameters, hence the plan quality. The observed average displacement of needles (1 mm) and of prostate (0.57 mm) is quite small as compared with the average displacement noted in several other reports [A. A. Martinezet al., Int. J. Radiat. Oncol., Biol., Phys. 49(1), 61–69 (2001); S. J. Damore et al., Int. J. Radiat. Oncol., Biol., Phys. 46(5), 1205–1211 (2000); P. J. Hoskin et al., Radiotherm. Oncol. 68(3), 285–288 (2003); E. Mullokandov et al., Int. J. Radiat. Oncol., Biol., Phys. 58(4), 1063–1071 (2004)] in the literature.

Conclusions:

Although the decrease of quality of dosimetric and radiobiological parameters occurs, this does not cause clinically unacceptable changes to the 3D dose distribution, according to our clinical protocol.
AN EFFICIENT PARALLEL SORTING COMPATIBLE WITH THE STANDARD QSORT
Authors: MAN DUHU , ITO YASUAKI , NAKANO KOJI
Published: August 2011

The main contribution of this paper is to present an efficient parallel sorting "psort" compatible with the standard qsort. Our parallel sorting "psort" is implemented such that its interface is compatible with "qsort" in C Standard Library. Therefore, any application program that uses standard "qsort" can be accelerated by simply replacing "qsort" call by our "psort". Also, "psort" uses standard "qsort" as a subroutine for local sequential sorting. So, if the performance of "qsort" is improved by anyone in the open source community, then that of our "psort" is also automatically improved.

To evaluate the performance of our "psort", we have implemented our parallel sorting in a Linux server with four Intel hexad-core processors (i.e. twenty four processor cores). The experimental results show that our "psort" is approximately 11 times faster than standard "qsort" using 24 processors.
RELIABLE COMMUNICATION ON EMULATED CHANNELS RESILIENT TO TRANSIENT FAULTS
Authors: YAMAUCHI YUKIKO , BEIN DOINA , MASUZAWA TOSHIMITSU
Published: August 2011

Topology embedding enables one to execute a protocol designed for a specific (virtual) topology on another (real) topology by embedding the virtual topology on the real topology. In this paper, we propose a self-stabilizing emulation technique that provides reliable communication on a virtual topology in the presence of transient faults in real topology. The proposed protocol improves the execution slowdown of previous two protocols [19, 20] and provides adaptive message delivery delay on the emulated channels, which is a new type of adaptability against transient faults.
FITNESS LANDSCAPES AND THE ANDREWS–CURTIS CONJECTURE
Authors: SWAN JERRY , OCHOA GABRIELA , KENDALL GRAHAM , EDJVET MARTIN
Published: August 2011

Attempts have been made to eliminate some potential counterexamples to the Andrews–Curtis conjecture using the combinatorial optimization methods of blind-search and the genetic algorithms meta-heuristic. Breadth-first search with secondary storage is currently the most successful method, which raises questions regarding the inferior performance of heuristic search. In order to understand the underlying reasons we obtain fitness landscape metrics for a number of balanced presentations and draw conclusions regarding the likely effectiveness of other meta-heuristics.
PSEUDO-RESONANCE INDUCED QUASI-PERIODIC BEHAVIOR IN STOCHASTIC THRESHOLD DYNAMICS
Authors: DITLEVSEN PETER D. , BRAUN HOLGER
Published: August 2011

Here we present a simple stochastic threshold model consisting of a deterministic slowly decaying term and a fast stochastic noise term. The process shows a pseudo-resonance, in the sense that for small and large intensities of the noise the signal is irregular and the distribution of threshold crossings is broad, while for a tuned intermediate value of noise intensity, the signal becomes quasi-periodic and the distribution of threshold crossings is narrow. The mechanism captured by the model might be relevant for explaining apparent quasi-periodicity of observed climatic variations where no internal or external periodicities can be identified.
PARTICLE FILTERS IN A MULTISCALE ENVIRONMENT: WITH APPLICATION TO THE LORENZ-96 ATMOSPHERIC MODEL
Authors: YEONG HOONG CHIEH , PARK JUN HYUN , NAMACHCHIVAYA N. SRI
Published: August 2011

The study of random dynamical systems involves understanding the evolution of state variables that contain uncertainties and that are usually hidden, or not directly observable. Therefore, state variables have to be estimated and updated based on system models using information from observational data, which themselves are noisy, in the sense that they contain uncertainties and disturbances due to imperfections in observational devices and disturbances in the environment within which data are being collected. The development of efficient data assimilation methods for integrating observational data in predicting the evolution of random state variables is thus an important aspect in the study of random dynamical systems. In this paper, we consider a particle filtering approach to nonlinear filtering in multiscale dynamical systems. Particle filtering methods [1–3] utilizes ensembles of particles to represent the conditional density of state variables using particle positions, distributed over a sample space. The distribution of an ensemble of particles is updated using observational data to obtain the best representation of the conditional density of the state variables of interest. On the other hand, homogenization theory [4, 5], allows us to estimate the coarse-grained (slow) dynamics of a multiscale system on a larger timescale without having to explicitly study the fast variable evolution on a small timescale. The results of filter convergence presented in [6] shows the convergence of the filter of the actual state variable to a homogenized solution to the original multiscale system, and thus we develop a particle filtering scheme for multiscale random dynamical systems that utilizes this convergence result. This particle filtering method is called the Homogenized Hybird Particle Filter, and it incorporates a multiscale computation scheme, the Heterogeneous Multiscale Method developed in [7], with the novel branching particle filter described in [8–10]. By incorporating a multiscale scheme based on homogenization of the original system, estimation of the coarse-grained dynamics using observational data is performed over a larger timescale, thus resulting in computational time and cost reduction in terms of the evolution of the state variables as well as functional evaluations for the filtering aspect. We describe the theory behind this combined scheme and its general algorithm, concluded with an application to the Lorenz-96 [11] atmospheric model that mimics midlatitude geophysical dynamics with microscopic convective processes.
IT'S ALL ABOUT THE DATA: CHALLENGES AND SOLUTIONS IN THE STUDY OF NASCENT ENTREPRENEURS
Authors: MARKOVA GERGANA , PERRY JOHN , FARMER STEVEN M.
Published: August 2011

Entrepreneurship research has been criticized for a lack of methodological rigor, although evidence suggests that from a methodological perspective, it is improving (Davidsson, 2006). In this paper, we systematically review the methods used in the study of nascent entrepreneurs to identify challenges associated with the data used in these studies. We also review the field's achievements — notably, the successful use of representative sampling of populations of nascent entrepreneurs — and we raise concerns about the predominant use of secondary data sets and the use of scales originally developed for large, established firms. Drawing on methodological advancements in other fields, we offer suggestions related to study design, data collection, sampling and measurement. Although some of the challenges we note are inherent to the nature of entrepreneurship, we hope our discussion can help researchers design better studies and better interpret their findings.
INSTITUTIONS AND ENTREPRENEURIAL INTENT: A CROSS-COUNTRY STUDY
Authors: ENGLE ROBERT L. , SCHLAEGEL CHRISTOPHER , DIMITRIADI NIKOLAY
Published: August 2011

This study examines a number of proposed relationships between formal and informal institutional factors that impact the entrepreneurial intent (EI) of 477 university business students in Germany, Russia and the United States, as well as similarities and differences in these relationships between countries. This is the first study, of which we are aware, to develop an instrument to measure the impact of formal institutional factors on EI based upon the World Bank's Doing Business Report. Overall, the results give only minor support for the influence of formal institutional factors on EI with the greater impact appearing to come from the informal institutions of need, social norms and parental experience. Theoretical and practical implications are discussed.
Genuine ARP (GARP)
Authors: Dangol Subash , Selvakumar S. , Brindha M.
Published: August 2011

Address Resolution Protocol (ARP) is used to map the network address (IP address) to a physical address (MAC address). Being a stateless protocol and lacking proper authentication mechanism in the ARP messages, ARP is vulnerable for cache poisoning attack. Attacker can perform Man-In-The-Middle (MITM) attack or Denial of Service (DoS) attack and can access sensitive information, modify the contents, or deny the host from getting services. Different techniques for the detection and prevention of ARP cache poisoning attack have been proposed. Detection techniques (such as ARPWatch and Intrusion Detection techniques) generate false positives. Some prevention technique makes change in the switch itself and some uses cryptographic techniques. Secure-ARP and Ticket based ARP (TARP) are cryptographic techniques but suffer from single point failure and ticket flooding attacks respectively. ARP is a stateless protocol and ARP messages lacks the address authentication mechanism. As an ARP reply is unicast, all host systems in the LAN are not aware of the attacker present in the LAN. In this paper, we have proposed a protocol known as "Genuine Address Resolution Protocol (GARP)". Two novel concepts, viz., broadcastbased reply, and the Certifier for proof of IP address ownership have been proposed in GARP. As a reply is broadcast, the host, whose IP the attacker is using for attack, is aware of the attacker and subsequently makes other hosts in the LAN also aware of the attacker. Thus, the protocol prevents possible attack from the same attacker in the future. Statefulness is achieved by two tables, viz., the pending table and the blacklist table. The pending table holds the reply till its genuineness is proved and the blacklist table holds the MAC of attacker. Furthermore, the Certificate Authority is responsible for monitoring the ARP activities, which intervenes with appropriate messages at appropriate instances. The Dynamic Host Configuration Protocol (DHCP) server could be loaded with the additional service of monitoring ARP activities. The protocol has been implemented on Linux operating system. GARP was tested for various possible cases of ARP cache poisoning attack. From the results, it could be inferred that the GARP provides security against ARP cache poisoning attacks.
Quality metrics for conceptual models for data warehouse focusing on dimension hierarchies
Authors: Gosain Anjana , Nagpal Sushama , Sabharwal Sangeeta
Published: August 2011

Multidimensional conceptual models have been accepted as the foundation for data warehouse designs. The quality of these models have significant effect on the quality of data warehouse and hence, in turn on the information quality. Few researchers have defined quality attributes for the conceptual models for data warehouse and have also proposed metrics to assess the quality attributes of these models objectively. The objective of this work is to propose candidate metrics to compute the structural complexity of multidimensional model. The main emphasis of this paper will be on the dimension hierarchies in multidimensional model. Though, these hierarchies play very significant role in analysing data at various granularity levels, their use enhances structural complexities of multidimensional model which can affect their understandability and modifiability and in turn maintainability.
An online cross view difference and behavior based kernel rootkit detector
Authors: Mahapatra Chandrabhanu , Selvakumar S.
Published: August 2011

Kernel level rootkits pose a serious threat today as they not only mask the presence of themselves but also mask the malware that comes attached with them. Rootkits achieve such stealthy behavior by manipulating the control flow of system calls by hooks and kernel objects, viz., driver and process list directly. Existing Antiviruses that rely on signature based techniques for detection of malwares are effective only against known rootkits. However, as hackers change coding style of rootkits, Antiviruses fail to detect them and rootkits and their malicious activities are hidden from the view of the administrator. Thus, all data on the compromised system becomes vulnerable to theft and all services running on it can be misused by the remote attacker without even the slightest chance of being discovered. Other rootkit detection techniques such as integrity checking, alternate trusted medium, and memory dumping require frequent offline analysis and fail to unload or block the rootkit.

This paper addresses, these challenges and proposes an online cross view difference and behavior based kernel rootkit detector to overcome them. Our proposed solution Kernel Rootkit Trojan Detector (KeRTD) is a host-based and cross view difference-based solution that enables online analysis and aids detection of rootkit immediately. A simple view difference of snapshot of Task manager in user mode and KeRTD Process and Driver List helps the detection of hidden rootkits and other hidden malwares. All rootkits follow a generic pattern of infection such as installing kernel hooks and modification of kernel objects, etc. This very generic behavior of rootkit is exploited in KeRTD to detect and restore the kernel hooks, thus blocking them from further infection. Every file and memory accesses are verified against Access Control List to avoid subversion of KeRTD and operating system kernel. This proposal has been implemented on windows operating system and tested for various methods of attack by kernel rootkits. The results confirm the detection of the kernel rootkits.
Bridging the data integration gap
Authors: Bennett Travis A. , Bayrak Coskun
Published: August 2011

The integration of multiple autonomous and heterogeneous data sources (both across the web and via a company intranet) has received much attention throughout the years, particularly due to its many applications in the fields of Artificial Intelligence and medical research data sharing. Data integration systems embody this work and have come very far in the past twenty years. The problem of designing such systems is characterized by a number of issues that are interesting from a theoretical point of view: answering queries using logical views, query containment and completeness, automatic integration of existing data sources via schema mapping tools, etc. In this work we discuss these issues, compare and contrast various proposed solutions (federated database systems and data warehouses), and finally propose a novel extension of the MVC (model, view, controller) web-based framework that allows for the rapid development and implementation of data integration systems solutions suitable for use on the web.
Introduction to Special Issue (Part 1)
Authors: Ladner Richard , VanDeGrift Tammy
Published: August 2011

This special issue includes the first set of articles addressing broadening participation in computing education. The articles span the stages of the pipeline, from introducing middle school children to computer science to retaining underrepresented groups at the university level. The preface presented here outlines the need for increasing the participation of underrepresented minorities, women, and people with disabilities in the development of technology. In addition, the preface summarizes the six articles included in this first (of two) issues on broadening participation.
The Role of Majority Groups in Diversity Programs
Authors: Rheingans Penny , Brodsky Anne , Scheibler Jill , Spence Anne
Published: August 2011

The underrepresentation of women in technical fields is a widely acknowledged national problem, limiting both the raw size of the talent pool and the diversity of experiences and perspectives of those who will design solutions to key problems facing society. Empowering women to succeed in these fields is clearly one important component of any solution. Because the population in those fields will likely continue to be overwhelmingly male for some time to come, men must also be a key component of the solution. Specifically, since the attitudes of the majority group are a strong determinant of climate, it is almost equally important to foster a population of men supportive of increasing the representation of women.

As at most universities and technical companies, women are a minority in all majors in the University of Maryland Baltimore County (UMBC) College of Engineering and Information Technology (COEIT). In most majors, they are a small minority. The UMBC Center for Women and Information Technology (CWIT) is dedicated to increasing the representation of women in engineering and information technology fields. At the heart of these efforts is the CWIT Scholar Program, a selective merit scholarship program for undergraduates majoring in engineering and IT who are committed to increasing the representation of women in those fields. In addition to financial support, the CWIT Scholar Program provides a supportive community, academic and professional development programming, networking opportunities, and a residential Living Learning Community. Almost from the beginning, some CWIT scholars have been men. 28 percent of current CWIT scholars are men.

Perhaps not surprisingly, female CWIT scholars have dramatically higher retention and completion rates than other women majoring in these fields. In this article, we look at a second effect of the CWIT Scholar Program, that of changing awareness and attitudes of the men who participate. We discuss programs and present results of a survey of attitudes regarding technical, academic, and gender issues in engineering and IT education. We disaggregate survey participants to show differences between the attitudes of women, scholar men, and men not participating in a diversity program.