bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of Matrix Pencil Algorithm to Mobile Robot Localization Using Hybrid DOA/TOA Estimation
Authors: Trinh Lan Anh , Duc Thang Nguyen , Kim Donghan , Lee Sungyoung , Chang Seongju
Published: December 2012

Localization plays an important role in robotics for the tasks of monitoring, tracking and controlling a robot. Much effort has been made to address robot localization problems in recent years. However, despite many proposed solutions and thorough consideration, in terms of developing a low-cost and fast processing method for multiple-source signals, the robot localization problem is still a challenge. In this paper, we propose a solution for robot localization with regards to these concerns. In order to locate the position of a robot, both the coordinate and the orientation of a robot are necessary. We develop a localization method using the Matrix Pencil (MP) algorithm for hybrid detection of direction of arrival (DOA) and time of arrival (TOA). TOA of the signal is estimated for computing the distance between the mobile robot and a base station (BS). Based on the distance and the estimated DOA, we can estimate the mobile robot's position. The characteristics of the algorithm are examined through analysing simulated experiments and the results demonstrate the advantages of our method over previous works in dealing with the above challenges. The method is constructed based on the low-cost infrastructure of radio frequency devices; the DOA/TOA estimation is performed with just single value decomposition for fast processing. Finally, the MP algorithm combined with tracking using a Kalman filter allows our proposed method to locate the positions of multiple source signals.
Concise Review: Acute Graft-Versus-Host Disease: Immunobiology, Prevention, and Treatment
Authors: Sung Anthony D. , Chao Nelson J.
Published: December 2012

Graft-versus-host disease (GVHD) is a major complication of allogeneic hematopoietic stem cell transplant (AHSCT) associated with significant morbidity and mortality. This review focuses on the pathophysiology, clinical features, prevention, and treatment of acute GVHD. Specifically, we explain how new discoveries in immunology have expanded our understanding of GVHD, in which tissue damage from chemotherapy or radiation results in cytokine release, which activates T cells, resulting in proliferation and differentiation, trafficking to target organs, and tissue destruction and inflammation. Insights into the mechanisms of this disease relate directly to the development of preventive strategies and therapies, such as immunosuppression, T-cell depletion, calcineurin inhibitors, CCR5 antagonists, gut decontamination, extracorporeal photopheresis, and more. We also discuss how GVHD affects the gut, liver, and skin, as well as diagnosis, grading, and scoring. We end by examining future directions of treatment, including new immunomodulators and biomarkers. Understanding the immunobiology of GVHD and developing effective preventions and treatments are critical to the continuing success of AHSCT.
The Molecular Genetics and Cellular Mechanisms Underlying Pulmonary Arterial Hypertension
Authors: Machado Rajiv D.
Published: December 2012

Pulmonary arterial hypertension (PAH) is an incurable disorder clinically characterised by a sustained elevation of mean arterial pressure in the absence of systemic involvement. As the adult circulation is a low pressure, low resistance system, PAH represents a reversal to a foetal state. The small pulmonary arteries of patients exhibit luminal occlusion resultant from the uncontrolled growth of endothelial and smooth muscle cells. This vascular remodelling is comprised of hallmark defects, most notably the plexiform lesion. PAH may be familial in nature but the majority of patients present with spontaneous disease or PAH associated with other complications. In this paper, the molecular genetic basis of the disorder is discussed in detail ranging from the original identification of the major genetic contributant to PAH and moving on to current next-generation technologies that have led to the rapid identification of additional genetic risk factors. The impact of identified mutations on the cell is examined, particularly, the determination of pathways disrupted in disease and critical to pulmonary vascular maintenance. Finally, the application of research in this area to the design and development of novel treatment options for patients is addressed along with the future directions PAH research is progressing towards.
The Aftermath of the Global Financial Crisis and Union Strategies in the Australian Public Service
Authors: Roles Cameron , O’Donnell Michael , Fairbrother Peter
Published: December 2012

The Australian Labor government’s recognition of collective bargaining under its Fair Work Act 2009, and its efficiency drive from late 2011 across the Australian Public Service (APS), presented the Community and Public Sector Union (CPSU) with an opportunity to explore means of union renewal following a decade of conservative governments focused on union exclusion. An expanding budget deficit in 2011 placed considerable financial constraints on Australian government revenue. The Labor government increased the annual “efficiency dividend”, or across the board cuts in funding, from 1.5 per cent in May 2011 to 4 per cent in November 2011 as it attempted to achieve a budget surplus. This placed considerable pressure on agency management to remain within tight constraints on wage increases and to find budget savings, resulting in growing job losses from 2011. There was also considerable central oversight over bargaining outcomes throughout this bargaining round, with the Australian Public Service Commission (APSC) involved at all stages of the agreement-making process, to the frustration of many agencies and the CPSU. Nevertheless, throughout the 2011-12 bargaining round, the CPSU worked with its members to develop creative forms of industrial action, such as one minute stoppages in the Defence department. The union also mobilized an overwhelming majority of APS employees to vote “no” in response to initial offers put by agency managements. In addition, the CPSU focused on winning bargaining concessions in politically sensitive government agencies and then flowing these concessions to other agencies. Typical of this approach were the agreements reached in the Immigration department and Customs agency. Union recruitment activities over 2011 resulted in a substantial rise in membership and enhanced communications with members through workplace meetings, telephone and internet communications, and emails. Such union initiatives highlight the potential for enhanced union capacities and mobilization during a time of growing austerity.
Concilier vie familiale et vie professionnelle en France : les disparités d’horaires de travail
Authors: Bustreel Anne , Cornuau Frédérique , Pernod-Lemattre Martine
Published: December 2012

La France se caractérise aujourd’hui par une forte proportion de salariés ayant des contraintes familiales et par un nombre élevé d’entreprises qui flexibilisent la durée et les horaires de travail : comment la diffusion de ces nouvelles contraintes temporelles affectent-elles les femmes, et plus particulièrement les mères ? Une typologie des conditions temporelles d’emploi des salariés français intégrant la durée du travail, la souplesse horaire dont bénéficie le salarié et la « localisation » de son temps de travail, construite à partir de l’enquête « Familles et employeurs » (Ined-Insee, 2004-2005), fait apparaître une surreprésentation des femmes dans les emplois les plus souples, mais aussi les plus contraignants temporellement, alors que l’effet de la présence d’enfant semble assez mineur.

Trois hypothèses sont testées pour expliquer les conditions temporelles d’emploi : la préférence des salariés pour des horaires de travail commodes, les caractéristiques productives des emplois et le rapport de force salarié-employeur. Les résultats montrent que le fait d’avoir de jeunes enfants n’est pas corrélé aux conditions temporelles d’emploi. Être une femme accroît la probabilité d’avoir des horaires hyper-souples (plutôt que standards contraints) et diminue la probabilité d’avoir des horaires longs souples et non standards contraints. L’hypothèse d’une sélection en fonction des préférences n’est pas confirmée par l’analyse alors que les exigences productives des emplois et des employeurs ainsi que le pouvoir de négociation des salariés exercent des effets significatifs et expliquent la surreprésentation des femmes dans les horaires fragmentés contraints.
Exploring the Relationship Between Anxiety and Insistence on Sameness in Autism Spectrum Disorders
Authors: Gotham Katherine , Bishop Somer L. , Hus Vanessa , Huerta Marisela , Lund Sabata , Buja Andreas , Krieger Abba , Lord Catherine
Published: December 2012

Elevated anxiety symptoms are one of the most common forms of psychopathology to co‐occur with autism spectrum disorders (ASDs). The purpose of this study was to explore the association between anxiety and ASD symptoms, particularly the degree to which the relationship is explained by insistence on sameness (IS) behaviors and/or cognitive ability. The sample included 1429 individuals aged 5:8–18:0 years who participated in the Simons Simplex Collection, a genetic consortium study of ASD. Child Behavior Checklist Anxiety Problems T‐scores and Autism Diagnostic Interview‐Revised “IS“ item raw totals were treated as both categorical and continuous measures of anxiety and IS, respectively. Chronological age, verbal intelligence quotient (IQ), and a variety of ASD phenotype‐related and other behavioral variables were assessed for potential association with anxiety and IS. Anxiety and IS continuous variables were minimally, although significantly, associated with each other and with chronological age and verbal IQ. Neither anxiety nor IS was associated with other core autism diagnostic scores. Anxiety was associated with a variety of other psychiatric and behavioral symptoms in ASD, including irritability, attention problems, and aggression, while IS was not. Anxiety and IS appear to function as distinct constructs, each with a wide range of expression in children with ASD across age and IQ levels. Thus, both variables could be of use in ASD behavioral research or in dimensional approaches to genetic exploration. Unlike IS, however, anxiety is related to non‐ASD‐specific behavioral symptoms. Autism Res 2012, ●●: ●●–●●. © 2012 International Society for Autism Research, Wiley Periodicals, Inc.
Assessing ongoing sources of dissolved-phase polychlorinated biphenyls in a contaminated stream
Authors: Dang Viet D. , Walters David M. , Lee Cindy M.
Published: December 2012

Few studies assess the potential of ongoing sources of “fresh” polychlorinated biphenyls (PCBs) to aquatic systems when direct discharge to the environment has been eliminated. In the present study, the authors used single-layered, low-density polyethylene samplers (PEs) to measure total PCB concentrations, congener profiles, and enantiomeric fractions (EFs) in a contaminated stream and to provide multiple lines of evidence for assessing ongoing inputs of PCB. Concentrations were well above background levels that have been monitored for years. Concentrations significantly increased with distance, the farthest downstream PE concentrations being almost five times greater than those at 79 m downstream of a historical point source. The PCBs in the PEs at 79 m downstream of the contamination source were dominated by low KOW congeners, similar to those in the mixture of Aroclors 1016 and 1254 (4:1 v/v) historically released from the former capacitor manufacturer. The only two chiral congeners detected in the PEs downstream were PCBs 91 and 95. The EF values were nonracemic for PCB 91, while the values were either racemic or near racemic for PCB 95. Increased PCB concentrations with distance and a congener composition of predominantly low-weight congeners in the PEs at 79 m downstream of the plant site suggested an ongoing PCB source from the plant site. Chiral signatures suggested aerobic biotransformation of dissolved PCBs but did not shed any light on possible ongoing PCB inputs. Environ. Toxicol. Chem. 2013;32:535–540. © 2012 SETAC
High lipophilicity and high daily dose of oral medications are associated with significant risk for drug-induced liver injury
Authors: Chen Minjun , Borlak Jürgen , Tong Weida
Published: December 2012

Drug-induced liver injury (DILI) is a leading cause of drug failure in clinical trials and a major reason for drug withdrawals from the market. Although there is evidence that dosages of ≥100 mg/day are associated with increased risk for hepatotoxicity, many drugs are safe at such dosages. There is an unmet need to predict risk for DILI more reliably, and lipophilicity might be a contributing factor. We analyzed the combined factors of daily dose and lipophilicity for 164 US Food and Drug Administration–approved oral medications and observed high risk for hepatotoxicity (odds ratio [OR], 14.05; P < 0.001) for drugs given at dosages ≥100 mg/day and octanol-water partition coefficient (logP) ≥3. This defined the “rule-of-two.” Similar results were obtained for an independent set of 179 oral medications with 85% of the rule-of-two positives being associated with hepatotoxicity (OR, 3.89; P < 0.01). Using the World Health Organization's Anatomical Therapeutic Chemical classification system, the rule-of-two performed best in predicting DILI in seven therapeutic categories. Among 15 rule-of-two positives, 14 were withdrawn from hepatotoxic drugs, and one was over-the-counter medication labeled for liver injury. We additionally examined drug pairs that have similar chemical structures and act on the same molecular target but differ in their potential for DILI. Again, the rule-of-two predicted hepatotoxicity reliably. Finally, the rule-of-two was applied to clinical case studies to identify hepatotoxic drugs in complex comedication regimes to further demonstrate its use. Conclusion: Apart from dose, lipophilicity contributes significantly to risk for hepatotoxicity. Applying the rule-of-two is an appropriate means of estimating risk for DILI compared with dose alone. (HEPATOLOGY 2013)
A Finite Element Study about CAM-Out Failure of the Recess-Screwdriver Interfaces for the Cold-Welded Periarticular Fixation
Authors: Chien C.-Y. , Chuang W.-H. , Tsai W.-C. , Lin S.-C. , Luh Y.-P. , Chen Y.-J.
Published: December 2012

In clinical practice, cam-out failure at the recess-screwdriver interfaces may occur when tightening or removing a bone screw. For titanium-based periarticular fixation, the literature reports have revealed that cold welding at the plate-screw interfaces makes the screw recess especially prone to cam-out failure during screw removal. In this study, the effects of the four recess shapes (cross, hexagon, star, and crest), three torque value (0.8, 1.0, and 1.2N-m), and the three interfacial misfits (0.00, 0.05, and 0.10mm) on the cam-out failure were numerically evaluated. The free-rotation angle, torque-recess angle, slippage-resisting length, and interfacial stress distribution were defined and chosen as comparison indices for the twelve recess-misfit variations. The results revealed that the interfacial slippage, torque transfer, and stress distribution are highly related to both recess shape and interfacial misfit. The stresses of all recesses and screwdrivers consistently initiate at the contact sites. However, the recess profile significantly affects the stress propagation. The stress patterns of the recess and screwdriver are quite different between the cross-star and hexagon-crest groups. The cross-star group is superior to the hexagon-crest group in terms of the torque-recess angle and slippage-resisting length over. This makes the recess of the cross-star group less stressed than its counterpart. However, the volumes of the cross and the star screwdriver are more highly stressed than the hexagon due to the irregular shape and the thinner flange, respectively. The greater torque and misfit increase the performance difference between the four recess designs. In conclusion, the geometry of the cross and star groups provide the better performance of the screw recess in terms of torque-transferring efficiency and slippage-resisting ability. If the screwdriver material is properly strengthened and the stress-concentrating corners are modified, the cross and star groups would be the optimal designs that protects and extends the lifetime of both recess and reused screwdriver.
Improving Combustion Intensity and Modulating Flame Behaviors Using Helical-Grooved Cones
Authors: Yen S. C. , Shih C. L.
Published: December 2012

Four helical-grooved cones were installed behind an unconfined combustion nozzle to increase the bluff-body effect and turbulence intensity (T.I.). The cone configurations included a smooth cone and the other three cones cut with 1, 2 and 3 helical v-grooves. Experimental results showed that the helical v-grooves transformed the axial momentum (or the axial velocity) to the angular momentum (or the angular velocity). TheT.I.was enhanced by increasing the tangential component of fuel-jet momentum. The direct photography and thermocouple were utilized to observe the flame structures and to delineate the characteristic flame modes, flame length, temperature distribution, and combustion intensity. The flame modes were classified as jet flame, flickering flame, bubble flame, recirculation flame, lifted flame and ring flame. The flame length decreases as the groove number increases. The increasedT.I.and groove number (or bluff-body effect) improve the fuel-air mixing. The total combustion intensity increases with annular-air jet and with the groove number.
The scaling of collisionless magnetic reconnection in an electron–positron plasma with non-scalar pressure
Authors: HOSSEINPOUR M. , MOHAMMADI M. A. , BIABANI S.
Published: December 2012

Collisionless magnetic reconnection via tearing instability in non-relativistic electron–positron (pair) plasma with an anisotropic pressure is investigated. The equilibrium magnetic field is considered to be sheared force-free, and a set of linearized collisionless Magnetohydrodynamics equations describes the evolution of reconnection dynamics. A linear analytical analysis, based on scaling, demonstrates that in such a pair plasma, breaking the frozen in flow constraint for field lines can be mainly provided by the non-gyrotropic pressure of electrons and positrons (rather than the particle bulk inertia) when the current sheet width is smaller than the particle Larmor radius (Δx < rL). This condition is satisfied when β > d2 (d = c/ωp is the particle skin-depth with the electron/positron frequency ωp and β = 8πP(0)/B02 ⪡ 1). Meanwhile, on top of the Lorentz force and in the absence of the reconnection facilitating mechanism of the Hall effect, non-scalar pressure force can accelerate bulk plasma into the diffusion region at the scale lengths of the order of dx. Therefore, the respective regime of tearing instability proceeds much faster compared with the case of an isotropic pressure with a new dimensionless growth rate of (γτA) ~ d.
Australian interests, bifocalism, bipartisanship, and the Antarctic Treaty System
Authors: Haward Marcus , Cooper Nicholas
Published: December 2012

This article explores the character of domestic political support for the Australian Antarctic Territory and Australia's involvement in the Antarctic Treaty System, using the linked frames of bifocalism and bipartisanship. After first unpacking these concepts it explores how they have shaped the extent and form of Australia's Antarctic endeavours from the 1930s to the present day. It is argued that the analysis shows that bipartisan commitment to Australian interests in Antarctica is framed through bifocalism: first, Australian national interests are closely linked to maintenance of the Antarctic Treaty and Antarctic Treaty System, and second, presentation of these national interests is not inimical to commitments to the Antarctic Treaty and Antarctic Treaty System.
Ultrashort-pulse MeV positron beam generation from intense Compton-scattering γ-ray source driven by laser wakefield acceleration
Authors: Luo W. , Zhuo H.B. , Ma Y.Y. , Yang X.H. , Zhao N. , Yu M.Y.
Published: December 2012

Intense Compton-scattering γ-ray radiation driven by laser wakefield acceleration (LWFA) and generation of ultrashort positron beams are investigated by Monte Carlo simulation. Using an LWFA driven GeV electron bunch and a 45 femtosecond, 90 mJ/pulse, and 10 Hz Ti:Sapphire laser for driving the Compton scattering, fs γ-ray pulses were generated. The latter have a flux of ≥108/s, peak brightness of ≥1020 photons/(s mm2 mrad2 0.1% bandwidth), and photon energy of 5.9 to 23.2 MeV. The γ-ray pulses then impinge on a thin high-Z target. More than 107 positrons/s in the form of sub-100 fs pulses at several MeV can be produced. Such ultrashort positron pulses can be useful as the pump-probe type positron annihilation spectroscopy as well as in other applications.
Quantum attacks on pseudorandom generators
Authors: GUEDES ELLOÁ B. , DE ASSIS F. M. , LULA BERNARDO
Published: December 2012

There are advantages in the use of quantum computing in the elaboration of attacks on certain pseudorandom generators when compared with analogous attacks using classical computing. This paper presents a polynomial time quantum attack on the Blum–Micali generator, which is considered secure against threats from classical computers. The proposed attack uses a Grover inspired procedure together with the quantum discrete logarithm, and is able to recover previous and future outputs of the generator under attack, thereby completely compromising its unpredictability. The attack can also be adapted to other generators, such as Blum–Micali generators with multiple hard-core predicates and generators from the Blum–Micali construction, and also to scenarios where the requirements on the bits are relaxed. Such attacks represent a threat to the security of the pseudorandom generators adopted in many real-world cryptosystems.
A Pilot Double Blind Randomized Placebo Controlled Trial of a Prototype Computer-Based Cognitive Behavioural Therapy Program for Adolescents with Symptoms of Depression
Authors: Stasiak Karolina , Hatcher Simon , Frampton Christopher , Merry Sally N.
Published: December 2012

Background:Depressive disorder is common in adolescents and largely untreated. Computers offer a way of increasing access to care. Computerized therapy is effective for depressed adults but to date little has been done for depressed adolescents.Aims:The objective of this study was to examine the feasibility, acceptability, and effects of The Journey, a computerized cognitive behavioural therapy (cCBT) program for depressed adolescents.Method:Thirty-four adolescents (mean age 15.2 years,SD= 1.5) referred by school counsellors were randomly assigned to either cCBT or a computer-administered attention placebo program with psychoeducational content (CPE). Participants completed the intervention at school. Data were collected at baseline, post-intervention and at a 1-month follow-up. The primary outcome measure was the Child Depression Rating Scale Revised (CDRS-R); secondary outcome measures were: RADS-2; Pediatric Quality of Life Inventory; Adolescent Coping Scale (short form); response and remission rates on CDRS-R. Completion rates and self-reported satisfaction ratings were used to assess feasibility and acceptabililty of the intervention.Results:Ninety-four percent of cCBT and 82% of CPE participants completed the intervention. Eighty-nine percent liked The Journey a lot or thought it was “okay” and 89% of them would recommend it for use with others as is or after some improvement. Adolescents treated with cCBT showed greater symptom improvement on CDRS-R than those treated with CPE program (mean change on cCBT = 17.6, CI = 14.13–21.00; CPE = 6.06, CI = 2.01–10.02;p< .001).Conclusions:It is feasible, acceptable and efficacious to deliver computerized CBT to depressed adolescents in a school setting. Generalizability is limited by the size of the study.
Religion and Support for Democracy in Bosnia-Herzegovina
Authors: Valenta Marko , Strabac Zan
Published: December 2012

This article examines the relationship between religiosity and support for democracy in Bosnia-Herzegovina. Using data from the last World Values Survey, we examine levels of religiosity among Bosniaks, Serbs, and Croats, and their support for democracy. The influence of religiosity on support for democracy is also explored. The results indicate that religiosity has a negative influence on support for democracy, and it is particularly true for individuals who do not support the separation of the religious from the political sphere and who exhibit lower support for democracy. The article also examines different levels of religiosity among the three groups, controlling for a wide range of variables. We conclude that there is basically no difference in support for democracy between Croats and Bosniaks, while Serbs exhibit somewhat lesser support for democracy than members of the other two ethnic groups. Serbs also seem to be somewhat less religious than Bosniaks and Croats. Opposition to separation of the religious from the political sphere is a major source of lack of support for democracy among Croats and Bosniaks, but not among Serbs.
16‐year simulation of Arctic black carbon: Transport, source contribution, and sensitivity analysis on deposition
Authors: Sharma S. , Ishizawa M. , Chan D. , Lavoué D. , Andrews E. , Eleftheriadis K. , Maksyutov S.
Published: December 2012

Arctic regional climate is influenced by the radiative impact of aerosol black carbon (BC) both in the atmosphere and deposited on the snow and ice covered surfaces. The NIES (National Institute for Environmental Studies) global atmospheric transport model was used, with BC emissions from mid‐latitude fossil fuel and biomass burning source regions, to simulate BC concentrations with 16 year period. The model‐simulated BC agreed well with the BC observations, including the trends and seasonality, at three Arctic sites: Alert (Nunavut, Canada), Barrow (Alaska, USA), and Zepplin, Ny‐Ålesund (Svalbard, Norway). The equivalent black carbon (EBC, absorption inferred BC) observations at the three Arctic locations showed an overall decline of 40% from 1990 to 2009; with most change occurring during early 1990s. Model simulations confirmed declining influence on near surface BC contribution by 70% , and atmospheric BC burden by one half from the Former Soviet Union (FSU) BC source region over 16 years. In contrast, the BC contribution from the East Asia (EA) region has little influence at the surface but atmospheric Arctic BC burden increased by 3 folds. Modelled dry deposition is dominant in the Arctic during wintertime, while wet deposition prevails at all latitudes during summer. Sensitivity analyses on the dry and wet deposition schemes indicate that parameterizations need to be refined to improve on the model performance. There are limitations in the model due to simplified parameterizations and remaining model uncertainties, which requires further exploration of source region contributions, especially from growing EA source region to Arctic BC levels in the future is warranted.
Microbial hitchhikers on intercontinental dust: catching a lift in Chad
Authors: Favet Jocelyne , Lapanje Ales , Giongo Adriana , Kennedy Suzanne , Aung Yin-Yin , Cattaneo Arlette , Davis-Richardson Austin G , Brown Christopher T , Kort Renate , Brumsack Hans-Jürgen , Schnetger Bernhard , Chappell Adrian , Kroijenga Jaap , Beck Andreas , Schwibbert Karin , Mohamed Ahmed H , Kirchner Timothy , de Quadros Patricia Dorr , Triplett Eric W , Broughton William J , Gorbushina Anna A
Published: December 2012

Ancient mariners knew that dust whipped up from deserts by strong winds travelled long distances, including over oceans. Satellite remote sensing revealed major dust sources across the Sahara. Indeed, the Bodélé Depression in the Republic of Chad has been called the dustiest place on earth. We analysed desert sand from various locations in Chad and dust that had blown to the Cape Verde Islands. High throughput sequencing techniques combined with classical microbiological methods showed that the samples contained a large variety of microbes well adapted to the harsh desert conditions. The most abundant bacterial groupings in four different phyla included: (a) Firmicutes—Bacillaceae, (b) Actinobacteria—Geodermatophilaceae, Nocardiodaceae and Solirubrobacteraceae, (c) Proteobacteria—Oxalobacteraceae, Rhizobiales and Sphingomonadaceae, and (d) Bacteroidetes—Cytophagaceae. Ascomycota was the overwhelmingly dominant fungal group followed by Basidiomycota and traces of Chytridiomycota, Microsporidia and Glomeromycota. Two freshwater algae (Trebouxiophyceae) were isolated. Most predominant taxa are widely distributed land inhabitants that are common in soil and on the surfaces of plants. Examples include Bradyrhizobium spp. that nodulate and fix nitrogen in Acacia species, the predominant trees of the Sahara as well as Herbaspirillum (Oxalobacteraceae), a group of chemoorganotrophic free-living soil inhabitants that fix nitrogen in association with Gramineae roots. Few pathogenic strains were found, suggesting that African dust is not a large threat to public health.
Hydroacoustical emitter based on zero-order antisymmetric Lamb wave in a piezoelecrtric plate
Authors: Kuznetsova Iren E. , Zaitsev Boris D. , Borodina Irina A. , Teplykh Andrey A. , Kolesov Vladimir V. , Sknarya Anatolii V. , Petrova Nadezhda G. , Nosov Aleksander V.
Published: December 2012

A piezoelectric plate supporting the propagation of antisymmetric zero-order (A0) Lamb wave is proposed to be used as a hydroacoustical waveguide emitter that transmits a bulk acoustic wave into a liquid. The emitter's directional pattern has been theoretically and experimentally examined for a frequency band of 89–107 kHz. An angular acoustic beam scanning was revealed to be realized by varying the A0 wave frequency. It is shown that, unlike complicated emitting systems of phased array type, this nonmechanical scanning could be realized in a simple device. The obtained results are in a good agreement with the theoretical ones.
Size dependent polarization reversal at nanoscale metal-ferroelectric interfaces
Authors: Kraya R. A. , Kraya L. Y.
Published: December 2012

Ferroelectric oxides possess a unique set of physical properties that have not been maximally exploited due to a lack of understanding of the origins of the switching behavior. Currently, controversy exists over whether switching in ferroelectric oxides is due to polarization or defect mediated switching. Here, we use ultra-high vacuum scanning tunneling microscopy and atomic force microscopy to investigate the process of polarization reversal and to assess the effect of the electronic structure and conductance on the switching behavior of single crystal BaTiO3 (001). Measurements of the local density of states revealed the surface switching behavior was initially due to polarization and that a transition occurred to defected mediated switching after repeated switching cycles. Atomic force microscopy investigations of the size effects at nanoscale Au-BaTiO3 (001) interfaces revealed asymmetric polarization reversal at large interfaces with a convergence to symmetric behavior as the size scale decreased, in agreement with the tunneling-based scanning tunneling microscopy technique.
CdS nanofilms: Effect of film thickness on morphology and optical band gap
Authors: Kumar Suresh , Kumar Santosh , Sharma Pankaj , Sharma Vineet , Katyal S. C.
Published: December 2012

CdS nanofilms of varying thickness (t) deposited by chemical bath deposition technique have been studied for structural changes using x-ray diffractometer (XRD) and transmission electron microscope (TEM). XRD analysis shows polycrystalline nature in deposited films with preferred orientation along (002) reflection plane also confirmed by selected area diffraction pattern of TEM. Uniform and smooth surface morphology observed using field emission scanning electron microscope. The surface topography has been studied using atomic force microscope. The optical constants have been calculated from the analysis of %T and %R spectra in the wavelength range 300 nm-900 nm. CdS nanofilms show a direct transition with red shift. The optical band gap decreases while the refractive index increases with increase in thickness of nanofilms.
Partial focusing by a bulk metamaterial formed by a periodically loaded wire medium with impedance insertions
Authors: Kaipa Chandra S. R. , Yakovlev Alexander B.
Published: December 2012

In this paper, a uniaxial wire medium periodically loaded with metallic patches and lumped impedance insertions is proposed for partial focusing of electromagnetic radiation due to a magnetic line source. The analysis is based on the nonlocal homogenization model for a bi-layer mushroom structure with generalized additional boundary conditions for loaded vias, and it is extended to a multilayered configuration with the transfer matrix approach. The proposed structure exhibits a high transmission and is nearly insensitive to the losses. The analytical results are validated against full-wave numerical simulations.
A model of the generation and transport of ozone in high-tension nozzle driven corona inside a novel diode
Authors: Vijayan T. , Patil Jagadish G.
Published: December 2012

The genesis and transport of ozone (O3) are investigated in a novel plasma diode and described in this paper. The innovative cathode (K) of this axial symmetric diode which operated at the high voltage (ϕ0), has a large number of sharpened nozzles located on different radial planes of its central tubular-mast and is encircled by the anode (A). The nozzles played the dual role of oxygen (O2) injection as well as creation of high electric field (E) in the A-K gap, enabled the formation of a cold corona. Electrons in the corona under the influence of E moved towards anode, collided with O2 and created the O radicals. O in turn joined the free O2 and formed O3. The evolution of O3 here is modeled in various O2 pressure (P), electron density (ne), and temperature (T) in terms of the major reaction modes involving e, O, O2, and O3. Typical steady state O3 density attained so in P ∼ bar, ne ∼ 1015 m−3 and T ∼ 300 K is over 1025 m−3 and that of O lower ∼1020 m−3. Both the O and O3 densities increased with an enhanced ne of avalanche multiplications in corona. O3 increased also with a higher P but the temporal O reversed in trend midway and reduced with P towards the steady state. A sharp decline in diode resistance with smaller A-K gap induced finite discharge current and led to the undesired heating of corona. It is shown that the O3 density reduced with the temperature rise but O density reduced with the T rise up to 500 K and then rose modestly with the further T increase.
Water formation through O2 + D pathway on cold silicate and amorphous water ice surfaces of interstellar interest
Authors: Chaabouni H. , Minissale M. , Manicò G. , Congiu E. , Noble J. A. , Baouche S. , Accolla M. , Lemaire J. L. , Pirronello V. , Dulieu F.
Published: December 2012

The formation of the first monolayer of water molecules on bare dust grains is of primary importance to understand the growth of the icy mantles that cover dust in the interstellar medium. In this work, we explore experimentally the formation of water molecules from O2 + D reaction on bare silicate surfaces that simulates the grains present in the diffuse interstellar clouds at visual extinctions (AV < 3 mag). For comparison, we also study the formation of water molecules on surfaces covered with amorphous water ice representing the dense clouds (AV ⩾ 3 mag). Our studies focus on the formation of water molecules in the sub-monolayer and monolayer regimes using reflection absorption infrared spectroscopy and temperature-programmed desorption techniques. We provide the fractions of the products, such as D2O and D2O2 molecules formed on three astrophysically relevant surfaces held at 10 K (amorphous olivine-type silicate, porous amorphous water ice, and nonporous amorphous water ice). Our results showed that the formation of D2O molecules occurs with an efficiency of about 55%–60% on nonporous amorphous water ice and about 18% on bare silicate grains surfaces. We explain the low efficiency of D2O water formation on the silicate surfaces by the desorption upon formation of certain products once the reaction occurs between O2 and D atoms on the surface. A kinetic model taking into account the chemical desorption of newly formed water supports our conclusions.
Electron-recoil ion and recoil ion-projectile coincidence techniques applied to obtain absolute partial collision cross sections
Authors: Wolff W. , de Souza Ihani J. , Tavares André C. , de Oliveira G. F. S. , Luna H.
Published: December 2012

We present in detail an alternative experimental set-up and data analysis, based on the electron-recoil ion and recoil ion-projectile coincidence techniques, that enable the measurement of partial pure ionization and partial charge exchange cross sections for an effusive gas jet set-up, where the absolute target density and recoil ion efficiency cannot be measured directly. The method is applied to the ionization of helium atoms due to collision with partially stripped C3 + projectiles. In order to check the method, the results are compared to data available in the literature where the target density and recoil ion detection efficiency were measured directly. The pure ionization channel is compared to the electron capture channel.
Magnetic emittance suppression using a bucking coil for a dc photocathode electron gun
Authors: Nagai Ryoji , Hajima Ryoichi , Nishimori Nobuyuki
Published: December 2012

Magnetic emittance suppression was demonstrated using a bucking coil for a dc photocathode electron gun. The magnetic emittance is derived from a leakage magnetic field on the cathode surface originating from a solenoid lens, and is important for realizing a high brightness dc photocathode electron gun. In order to solve this problem, a bucking coil integrated solenoid lens has been developed. The solenoid lens consists of a main coil, a bucking coil, and a pure iron yoke. The bucking coil and the main coil are integrated in the same yoke in order to prevent distortion of the magnetic field due to misalignment of the two coils. The emittance was measured and calculated as a function of the exciting current of the bucking coil and as a function of the electron beam size on the cathode.
Is rectal gonorrhoea a lead indicator of HIV transmission among men who have sex with men in Victoria, Australia?
Authors: Wilkinson Anna L. , Lim Megan S. C. , Stoové Mark , Fairley Christopher K. , Chen Marcus , El-Hayek Carol , Denham Ian , Hellard Margaret
Published: December 2012

Objectives
To examine whether rectal gonorrhoea (RG; Neisseria gonorrhoeae) can be used as a lead indicator of trends in HIV diagnosis in men who have sex with men (MSM). Methods: Data from a metropolitan sexual health centre in Victoria, Australia, on RG and HIV tests in HIV-negative MSM from January 2006 to December 2011 were examined. Results: Allowing RG a 12-month lead over HIV showed no concordance in proportion positive (r = 0.27; P-value = 0.28). Conclusions: The data do not support use of RG trends as a lead indicator of trends in HIV among MSM.
Proximity and Investment: Evidence from Plant-Level Data
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Authors: Giroud Xavier
Published: December 2012

Proximity to plants makes it easier for headquarters to monitor and acquire information about plants. In this article, I estimate the effects of headquarters’ proximity to plants on plant-level investment and productivity. Using the introduction of new airline routes as a source of exogenous variation in proximity, I find that new airline routes that reduce the travel time between headquarters and plants lead to an increase in plant-level investment of 8% to 9% and an increase in plants’ total factor productivity of 1.3% to 1.4%. The results are robust when I control for local and firm-level shocks that could potentially drive the introduction of new airline routes, when I consider only new airline routes that are the outcome of a merger between two airlines or the opening of a new hub, and when I consider only indirect flights where either the last leg of the flight (involving the plant’s home airport) or the first leg of the flight (involving headquarters’ home airport) remains unchanged. Moreover, the results are stronger in the earlier years of the sample period and for firms whose headquarters is more time-constrained. In addition, they also hold at the extensive margin, that is, when I consider plant openings and closures.
Phosphorylation of eIF2α is responsible for the failure of the picornavirus internal ribosome entry site to direct translation from Sindbis virus replicons
Authors: Sanz Miguel Angel , Redondo Natalia , García-Moreno Manuel , Carrasco Luis
Published: December 2012

Translation directed by the poliovirus (PV) or encephalomyocarditis virus (EMCV) internal ribosome entry site (IRES) is very inefficient when expressed from Sindbis virus (SV) replicons. This inhibition can be rescued by co-expression of PV 2A protease (2Apro). Inhibition correlates with the extensive phosphorylation of eukaryotic initiation factor (eIF) 2α induced by SV replication. Confirmation that PV or EMCV IRES-driven translation can function when eIF2α is not phosphorylated was obtained in dsRNA-activated protein kinase knockout mouse embryonic fibroblasts (PKR−/− MEFs), where SV replication cannot induce eIF2α phosphorylation, and in variant S51A MEFs that express an unphosphorylatable eIF2α. In these cells, PV or EMCV IRES-dependent translation operated more efficiently than in wild-type MEFs. However, this translation was potently blocked when eIF2α was phosphorylated by the addition of thapsigargin to PKR−/− MEFs. In addition, when wild-type eIF2α was expressed in S51A MEFs or PKR was expressed in PKR−/− MEFs, PV IRES-dependent translation decreased. In both cases, the decrease in PV IRES-dependent translation correlated with the phosphorylation of eIF2α. Notably, PV 2Apro expression rescued PV IRES-driven translation in thapsigargin-treated PKR−/− MEFs. Taken together, these results demonstrated that PV IRES-driven translation can take place from SV replicons if eIF2α remains unphosphorylated. Remarkably, PV IRES-dependent translation was fully functional in this system when PV 2Apro was present, even if eIF2α was phosphorylated.
Early secretory pathway localization and lack of processing for hepatitis E virus replication protein pORF1
Authors: Perttilä Julia , Spuul Pirjo , Ahola Tero
Published: December 2012

Hepatitis E virus (HEV) is a positive-strand RNA virus and a major causative agent of acute sporadic and epidemic hepatitis. HEV replication protein is encoded by ORF1 and contains the predicted domains of methyltransferase (MT), protease, macro domain, helicase (HEL) and polymerase (POL). In this study, the full-length protein pORF1 (1693 aa) and six truncated variants were expressed byin vitrotranslation and in human HeLa and hepatic Huh-7 cells by using several vector systems. The proteins were visualized by three specific antisera directed against the MT, HEL and POL domains.In vitrotranslation of full-length pORF1 yielded smaller quantities of two fragments. However, these fragments were not observed after pORF1 expression and pulse–chase studies in human cells, and their production was not dependent on the predicted protease domain in pORF1. The weight of evidence supports the proposition that pORF1 is not subjected to specific proteolytic processing, which is unusual among animal positive-strand RNA viruses but common for plant viruses. pORF1 was membrane associated in cells and localized to a perinuclear region, where it partially overlapped with localization of the endoplasmic reticulum (ER) marker BAP31 and was closely interspersed with staining of the ER–Golgi intermediate compartment marker protein ERGIC-53. Co-localization with BAP31 was enhanced by treatment with brefeldin A. Therefore, HEV may utilize modified early secretory pathway membranes for replication.
A compact device for loading diamond anvil cells with low-boiling pressure-transmitting media
Authors: Zakharov Boris A. , Achkasov Andrey F.
Published: December 2012

A new compact laboratory device for loading diamond anvil cells with low-boiling pressure-transmitting media is described. This device allows, in particular, the easy loading of diamond anvil cells with pentane–isopentane (1:1) mixture at environmental temperatures up to 303 K and relative humidity at least up to 75–80%. The relatively simple design, the easy availability of materials used for the device and the application of liquid nitrogen as cooling agent allow the manufacture of such a device in a short time at almost any laboratory.
Fast acquisition of extensive X-ray diffraction patterns of a gas–liquid interface in grazing-incidence geometry
Authors: Konovalov Oleg V. , Vorobiev Alexei A.
Published: December 2012

The development of third-generation synchrotron sources has inspired qualitative and quantitative breakthroughs in structural studies of monomolecular organic layers. To study such systems formed at the gas–liquid interface, grazing-incidence diffraction (GID) has proved to be the most powerful technique. Until quite recently, in most cases, GID was performedviaa scanning approach with use of a collimating system in front of the detector to eliminate the effect of parallax and to achieve the required angular resolution. Owing to the long counting time required, this kind of measurement often introduces significant radiation damage to a sample and considerably restricts time-resolved studies, preventing the pursuit of emerging scientific areas such as the investigation of fast kinetic structural changes in two-dimensional systems. This problem can apparently become a real obstacle for the application of the scanning GID technique at fourth-generation synchrotron sources because of the extremely high X-ray fluxes involved. This article discusses the possibility of significantly reducing the measuring time and avoiding the beam parallax problem by using a high-brilliance submillimetre beam and a large-area two-dimensional detector (e.g.PILATUS) in a single-shot GID measurement on large-area sample surfaces. Both theoretical considerations of the problem and experimental GID results from monomolecular layers of behenic acid at the gas–water interface are presented, with a detailed description of the experimental conditions. The possibility of a diffraction imaging study of the texture of Langmuir monomolecular layers is demonstrated.
An Investigation of Die Wear Behavior During Aluminum Alloy 7075 Tube Extrusion
Authors: Zhang Cunsheng , Zhao Guoqun , Li Tingting , Guan Yanjin , Chen Hao , Li Peng
Published: December 2012

During hot extrusion process, die wear shortens markedly the service life of extrusion dies under the high-pressure, high-temperature conditions. In this paper, based on modified Archard's wear model, a user-defined subroutine for calculating die wear depth was developed and implanted into DEFORM-3D. On the basis of the numerical model, the die wear behavior during aluminum alloy 7075 tube extrusion has been investigated. The numerical results show that process variables have multiple effects on die wear behavior. With the increasing ram speed, wear depth of die bearing rises and then tends to decline gradually. From the ram speed of 15 mm/s, die wear depth begins to increase again. Wear depth rises suddenly with the increase of friction coefficient, then gradually reduces. When friction coefficient is greater than 0.8, wear depth tends to be a constant. A maximum wear depth occurs at 430 °C of billet temperature, and a minimum wear depth occurs at certain die temperature in the range of 400–425 °C. In addition, the required extrusion force has strong dependence on process variables. The extrusion force rises clearly with the increase of ram speed and friction coefficient and with the decrease of initial temperatures of billet and die.