bluuebunny/crossref_metadata_2025_split huggingface dataset:
Magnetic susceptibility of an antiferromagnetic system with disorder‐driven quantum critical behavior
Authors: Demishev Sergey 
Published: February 2010

AbstractBased on a simple model, which suggests the relation between paramagnetic temperature in the high‐temperature Curie–Weiss law and the low‐temperature power asymptotic of magnetic susceptibility, and taking recently discovered quantum critical (QC) system Tm1−xYbxB12 as an example, we provide arguments that the study of the link between low‐temperature and high‐temperature magnetic properties of the QC system may be helpful for determination of applicability of the disorder‐driven QC scenario for an experimental system.
Quantum phase transition between antiferromagnetic and charge order in the Hubbard–Holstein model
Authors: Bauer Johannes , Hewson Alex C. 
Published: February 2010

AbstractWe explore the quantum phase transitions between two ordered states in the infinite dimensional Hubbard–Holstein model at half filling. Our study is based on the dynamical mean field theory (DMFT) combined with the numerical renormalization group (NRG), which allows us to handle both strong electron–electron and strong electron–phonon interactions. The transition line is characterized by an effective electron–electron interaction. Depending on this effective interaction and the phonon frequency ω0 one finds either a continuous transition or discontinuous transition. Here, the analysis focuses on the behavior of the system when the electron–electron repulsion U and the phonon‐mediated attraction λ are equal. We first discuss the adiabatic and antiadiabatic limiting cases. For finite ω0 we study the differences between the antiferromagnetic (AFM) and charge order, and find that when present the AFM state has a lower energy on the line.
Quantum phase transitions in NbFe2 and Ca3Ru2O7
Authors: Duncan W. J. , Welzel O. P. , Moroni‐Klementowicz D. , Albrecht C. , Niklowitz P. G. , Grüner D. , Brando M. , Neubauer A. , Pfleiderer C. , Kikugawa N. , Mackenzie A. P. , Grosche F. M. 
Published: February 2010

AbstractWe examine the low temperature states of two transition metal compounds: (i) NbFe2 is poised on the threshold of ferromagnetism and can be pushed into a spin‐aligned state at low temperature by modifying the composition slightly. Stoichiometric NbFe2 has been reported as a rare example of low‐temperature spin density wave order in a d‐metal system. We have used pressure, field and composition tuning to examine the phase diagram of NbFe2. Near the quantum critical point, we find distinct non‐Fermi liquid forms of the resistivity and heat capacity, whereas we observe strong, hysteretic magnetoresistance effects deep in the ordered phase. (ii) Ca3Ru2O7 undergoes first a magnetic transition (TN = 56 K) and then a structural transition (TS = 48 K) on cooling. Most of the Fermi surface is gapped out at low temperature, leading to a very low carrier density and small Fermi surface pockets. Pressure suppresses both TN and TS and, for p > 3.5 GPa, induces a third low temperature state, which is robust up to at least 7.5 GPa.
Plasmas for texturing, cleaning, and deposition: towards a one pump down process for heterojunction solar cells
Authors: Moreno Mario , Daineka Dmitri , Roca i Cabarrocas Pere 
Published: February 2010

AbstractLow temperature plasma deposition of a‐Si:H thin films has emerged as a promising alternative for high efficiency hetero junction (HJ) solar cells. In this work we study plasma processes for texturing and cleaning c‐Si wafers pursuing a low cost dry fabrication process of HJ solar cells. We have studied two independent plasma processes: i) Texturing of c‐Si wafers using SF6 ‐ O2 plasmas in a RIE system, in order to reduce the surface reflectance and therefore improve the light trapping. The effects of the RF power and gas ratio on the c‐Si surface texture have been studied in detail. Highly textured surfaces, with very low reflectance values (around 6% in the range of 300 – 1000 nm) have been achieved. ii) Etching of the native oxide and passivation of the c‐Si surface by plasma, in a standard RF PECVD system. We used SiF4 plasma with optimized conditions for an efficient native oxide removal, and without breaking the vacuum, 40 nm of a‐Si:H were deposited in order to passivate the c‐Si surface. High effective lifetime values were obtained (τeff ≈ 1.5 ms), providing high implicit open circuit voltages (Voc ≈ 0.713 V) and low surface recombination velocities (Seff < 9 cm s‐1). (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrical properties of thin‐films wide‐band gap semiconductor TiO2 prepared by CVD
Authors: Bessergenev V. , Gomes H. L. 
Published: February 2010

AbstractHigh dielectric constant TiO2 thin films are promising for gate insulator in 100‐nm microelectronic technology. In this study rutile and anatase phase TiO2 thin films were prepared by Chemical Vapour Deposition (CVD) method. Bulk and surface chemical composition of thin films were characterized by high‐resolution Laser Ionization Mass Spectrometry (LIMS) and by X‐ray Photoemission Spectroscopy (XPS). Crystal structure was studied by (XRD). Silicon based Metal‐Insulator semiconductor (MIS) capacitors formed on the high‐k dielectric TiO2were fabricated and characterized using small signal impedance studies as function of frequency and current vs voltage measurements. As it was shown from I–V characteristics, the Shockley equation adequately describes the conductivity mechanism in low field region. By analysis of I–V characteristics it was also found that there is change in carrier conduction mechanism from Shockley regime to the nonlinear Frenkel–Poole mechanism. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Development of LASER fired contacts on silicon heterojunction solar cells for the application to rear contact structures
Authors: Muñoz D. , Desrues T. , Ribeyron P.‐J. , Orpella A. , Martin I. , Voz C. , Alcubilla R. 
Published: February 2010

AbstractIn this work, we present our progress in contacting both doped and undoped a‐Si:H layers using a LASER tool and show some applications for three different HJ solar cell designs: standard (p‐type), rear emitter (n‐type) and back contact (n‐type). First, we have fabricated 25 cm2 standard and rear emitter double heterojunction (DHJ) solar cells on planar 1‐5 Ω.cm n‐type FZ c‐Si wafers using intrinsic instead of the p‐doped a‐Si:H layers. The influence of the different parameters of the LASER firing (pitch, number of pulses and energy) has been deeply studied to find optimized conditions. Solar cells have been obtained systematically with reasonable efficiencies although we have observed that the Voc is limiting the efficiency. Finally, we have also performed the Laser Fired Contacts (LFC) on lowly‐doped (p) a‐Si:H layers to compare the results obtained. We have observed that the LFC of the rear emitter contact enhances both short circuit current and fill factor while keeping the same Voc (646 mV). This leads to a 0.8% absolute increase of the cell efficiency. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
a‐SiC:H films deposited by PECVD for MEMS applications
Authors: Pelegrini Marcus V. , Rehder Gustavo P. , Pereyra Inés 
Published: February 2010

AbstractIn this work, we report on the deposition of stoichiometric a‐SiC:H with high Young's modulus and hardness for MEMS applications. A series of samples was deposited using different r.f. power densities in a PECVD system in order to explore the limits of the silane starving plasma condition and investigate the change of the deposition rate. Further, the density of the material was measured by a floatation method for the different deposition conditions. The residual stress was measured in the as‐deposited films and reduced by post‐deposition annealing. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Convection in an African Easterly Wave over West Africa and the eastern Atlantic: A model case study of Helene (2006)
Authors: Schwendike Juliane , Jones Sarah C. 
Published: February 2010

AbstractConvective systems embedded in an African Easterly Wave (AEW) over West Africa and the eastern Atlantic in September 2006 are investigated. The study is based on COSMO model runs with a horizontal resolution of 2.8 km. The developing, mature and decaying phases of a mesoscale convective system over land are identified. Over the ocean, the convection consists of the development and decay of short‐lived systems. There are significant differences between the structure of convection over land and water. Over land, the updraught, heating and vertical vorticity are tilted in the vertical. Over water, the convective cores are upright and collocated with positive relative vorticity. The atmosphere is drier at mid‐levels over land, and stronger shear, downdraughts and a distinct cold pool occur. The influence of the convective systems on their environment is assessed with potential temperature and relative vorticity budgets for regions encompassing the convective systems. During the convective system's life cycle, the relative vorticity increased at the height of the African Easterly Jet over land due to the eddy‐flux term, whereas the relative vorticity maximum over the ocean moved downwards with time due to stretching. High values of low‐level relative vorticity were seen over the ocean before the AEW trough crossed the West African coast. The low‐level circulation that developed as a positive low‐level vorticity anomaly associated with the westward extension of the Saharan heat low moved over the Atlantic and southwestwards. In addition, positive vorticity associated with the low‐level monsoon flow contributed to this circulation. The cyclogenesis of Hurricane Helene was initiated when the mid‐level vorticity anomaly of the AEW moved over the low‐level circulation, initiating convection and enhancing the low‐level vorticity through vortex stretching. Copyright © 2010 Royal Meteorological Society
On the choice of the residual norm function in the interpretation of ARXPS data by regularized fitting
Authors: Paynter R. W. , Rondeau M. 
Published: February 2010

AbstractAngle‐resolved X‐ray photoelectron spectroscopy (ARXPS) data taken on a polystyrene film exposed to a nitrogen plasma are interpreted by the fitting of regularized depth profiles. Three ways of measuring the goodness of fit are compared—the χ2 statistic with variances drawn from the raw spectra, the χ2 statistic with variances drawn from the concentration figures obtained from the data analysis, and a simple sum of the squared differences (ssd) that does not require variances to be calculated. It is shown that for these data, the depth profiles obtained using an objective method for the choice of the regularization parameter are essentially identical irrespective of whether or how the variances are introduced into the calculation. Copyright © 2010 John Wiley & Sons, Ltd.
Annealing effect on the structural and magnetic properties of nickel ferrite thin films
Authors: Dixit G. , Singh J. P. , Srivastava R. C. , Agrawal H. M. , Choudhary R. J. , Gupta A. 
Published: February 2010

AbstractNickel ferrite is a soft magnetic material with inverse spinel structure. Soft ferrite films are used in microwave devices, integrated planar circuits, etc., because of their high resistivity. In this work, thin films of nickel ferrite were deposited on Si (100) substrate by using pulsed laser deposition (PLD) technique. The thickness of the film was measured by surface profilometer and also by X‐ray reflectivity (XRR). The films were annealed at three different temperatures to observe the effect on the structural and magnetic properties of the film. The films were characterised by X‐ray diffraction (XRD), Raman spectroscopy and vibrating sample magnetometer (VSM) to study the structural and magnetic properties. Copyright © 2010 John Wiley & Sons, Ltd.
Intercellular nanotubes: insights from imaging studies and beyond
Authors: Hurtig Johan , Chiu Daniel T. , Önfelt Björn 
Published: February 2010

AbstractCell‐cell communication is critical to the development, maintenance, and function of multicellular organisms. Classical mechanisms for intercellular communication include secretion of molecules into the extracellular space and transport of small molecules through gap junctions. Recent reports suggest that cells also can communicate over long distances via a network of transient intercellular nanotubes. Such nanotubes have been shown to mediate intercellular transfer of organelles as well as membrane components and cytoplasmic molecules. Moreover, intercellular nanotubes have been observed in vivo and have been shown to enhance the transmission of pathogens such as human immunodeficiency virus (HIV)‐1 and prions in vitro. These studies indicate that intercellular nanotubes may play a role both in normal physiology and in disease. WIREs Nanomed Nanobiotechnol 2010 2 260–276This article is categorized under:

Nanotechnology Approaches to Biology > Cells at the Nanoscale
Nanotechnology Approaches to Biology > Nanoscale Systems in Biology
The effects of early and late bone marrow transplantation in siblings with alpha‐mannosidosis. Is early haematopoietic cell transplantation the preferred treatment option?
Authors: Broomfield A. A. , Chakrapani A. , Wraith J. E. 
Published: February 2010

AbstractThis article documents both the neurological and physical outcomes of the first published set of siblings undergoing transplantation at differing ages for α‐mannosidosis. The older brother, the index case, was diagnosed at the age of 3 years and underwent transplantation at 13 years for the treatment of increasing somatic problems and recurrent infections. The younger brother had undergone transplantation pre‐symptomatically at 6 months of age. Their clinical, radiological and developmental outcomes are documented and compared with the previous published cases, with the case for early transplantation being weighted against other potential therapies.
Molecular differentiation of fourReptalusspecies (Hemiptera: Cixiidae)
Authors: Bertin S. , Picciau L. , Ács Z. , Alma A. , Bosco D. 
Published: February 2010

AbstractThe cixiid speciesReptalus quinquecostatus,R. cuspidatus,R. panzeriandR. melanochaetusare widely distributed in Europe and are receiving growing attention because of their potential role as phytoplasma vectors. Identifying theReptalusspecies is restricted to a few specialist entomologists and relies on the morphology of the male genitalia, hampering the identification of juveniles and females. This study provides the tools for species discrimination by integrating the morphological description, which is primarily for the genus identification, with new molecular assays, based on both ribosomal and mitochondrial DNA. PCR-RFLP assays carried out on the mitochondrial cytochrome oxidase I gene (COI) withAluI provided species-specific profiles for the fourReptalusspecies. Amplification of a ribosomal internal transcribed spacer (ITS2) region produced species-specific fragments of different sizes forR. quinquecostatus,R. melanochaetus,R. cuspidatusandR. panzeri. The digestion of the ITS2 PCR product withTaqI allowed the discrimination of these latter two species. This molecular identification key ensures reliable results and can be successfully applied not only to adults, but also to the nymphs feeding on the roots. The identification of the nymphs (i) extends the collection period of these monovoltine species to the whole year (adults are present for a short summer period) and (ii) allows the unambiguous identification of their actual host plants because nymphs are steady on the root system while adults tend to disperse onto other plants. Fast and reliable identification of theReptalusspecies provides useful help in monitoring activities and, therefore, in designing rational control strategies to protect crops from phytoplasma infection.
On the specific identity of specimens ofPhytoseiulus longipesEvans (Mesostigmata: Phytoseiidae) showing different feeding behaviours: morphological and molecular analyses
Authors: Tixier M.-S. , Ferrero M. , Okassa M. , Guichou S. , Kreiter S. 
Published: February 2010

AbstractThis paper focuses on the differentiation of specimens, identified asPhytoseiulus longipes, collected in four countries: Argentina, Brazil, Chile and South Africa. Two of these populations are known to feed and develop onTetranychus evansi, whereas the two others do not. As morphologically similar specimens can sometimes belong to different species and because differences in predatory behaviours exist among the four populations considered, we tested for the presence of cryptic species. Morphological and molecular experiments (12S rDNA) were carried out. The four studied populations ofP. longipescould be morphologically differentiated thanks to a combination of characters. However, these morphological differences are very small. The two populations that feed and develop onT. evansi(from Argentina and Brazil) are morphologically closer to each other than to the two other populations. Genetic distances among the four populations ofP. longipeswere very low, suggesting that despite their different feeding habits, all specimens belong to the same species. However, the populations associated withT. evansishowed some genetic differentiation from those that do not use this pest. This is the first time that this type of differentiation has been reported for the family Phytoseiidae. These results are of primary importance to ensure the success of biological control programs and to develop strains adapted to both crops and prey species.
Central carbon metabolism ofLeishmaniaparasites
Authors: SAUNDERS ELEANOR C. , DE SOUZA DAVID P. , NADERER THOMAS , SERNEE MARIJKE F. , RALTON JULIE E. , DOYLE MARIA A. , MACRAE JAMES I. , CHAMBERS JENNY L. , HENG JOANNE , NAHID AMSHA , LIKIC VLADIMIR A. , MCCONVILLE MALCOLM J. 
Published: February 2010

SUMMARYLeishmaniaspp. are sandfly-transmitted protozoa parasites that cause a spectrum of diseases in humans. Many enzymes involved inLeishmaniacentral carbon metabolism differ from their equivalents in the mammalian host and are potential drug targets. In this review we summarize recent advances in our understanding ofLeishmaniacentral carbon metabolism, focusing on pathways of carbon utilization that are required for growth and pathogenesis in the mammalian host. WhileLeishmaniacentral carbon metabolism shares many features in common with other pathogenic trypanosomatids, significant differences are also apparent.Leishmaniaparasites are also unusual in constitutively expressing most core metabolic pathways throughout their life cycle, a feature that may allow these parasites to exploit a range of different carbon sources (primarily sugars and amino acids) rapidly in both the insect vector and vertebrate host. Indeed, recent gene deletion studies suggest that mammal-infective stages are dependent on multiple carbon sourcesin vivo. The application of metabolomic approaches, outlined here, are likely to be important in defining aspects of central carbon metabolism that are essential at different stages of mammalian host infection.
ON TAIL INDEX ESTIMATION FOR DEPENDENT, HETEROGENEOUS DATA
Authors: Hill Jonathan B. 
Published: February 2010

In this paper we analyze the asymptotic properties of the popular distribution tail index estimator by Hill (1975) for dependent, heterogeneous processes. We develop new extremal dependence measures that characterize a massive array of linear, nonlinear, and conditional volatility processes with long or short memory. We prove that the Hill estimator is weakly and uniformly weakly consistent for processes with extremes that form mixingale sequences and asymptotically normal for processes with extremes that are near epoch dependent (NED) on some arbitrary mixing functional. The extremal persistence assumptions in this paper are known to hold for mixing,Lp-NED, and some non-Lp-NED processes, including ARFIMA, FIGARCH, explosive GARCH, nonlinear ARMA-GARCH, and bilinear processes, and nonlinear distributed lags like random coefficient and regime-switching autoregressions.Finally, we deliver a simple nonparametric estimator of the asymptotic variance of the Hill estimator and prove consistency for processes with NED extremes.
Pregnancy-associated listeriosis
Authors: JACKSON K. A. , IWAMOTO M. , SWERDLOW D. 
Published: February 2010

SUMMARYInfection by Listeria monocytogenes in pregnant women may result in fetal loss or invasive disease in the newborn. We examined listeriosis cases reported through the U.S. Listeria Initiative during 2004–2007. Cases were classified as pregnancy-associated if illness occurred in a pregnant woman or an infant aged <28 days. Of 758 reported Listeria cases, 128 (16·9%) were pregnancy-associated. Maternal infection resulted in four neonatal deaths and 26 (20·3%) fetal losses. Invasive illnesses in newborns (n=85) were meningitis (32·9%) and sepsis (36·5%). Pregnant women with Listeria were more likely to report Hispanic ethnicity (52·8% vs. 25·6%, respectively; OR 3·3 95% CI 2·2–4·8) than mothers giving live birth in the USA during 2005 and were more likely to report consumption of Mexican-style cheese (OR 2·6, 95% CI 1·6–4·2) than were non-pregnant patients with Listeria infection. Pregnant woman comprised a considerable proportion of reported listeriosis cases. Further declines in pregnancy-associated listeriosis will require education about avoiding high-risk foods, and continued regulatory and industry efforts to decrease Listeria in foods.
Modelling seasonality and viral mutation to predict the course of an influenza pandemic
Authors: SHI P. , KESKINOCAK P. , SWANN J. L. , LEE B. Y. 
Published: February 2010

SUMMARYAs the 2009 H1N1 influenza pandemic (H1N1) has shown, public health decision-makers may have to predict the subsequent course and severity of a pandemic. We developed an agent-based simulation model and used data from the state of Georgia to explore the influence of viral mutation and seasonal effects on the course of an influenza pandemic. We showed that when a pandemic begins in April certain conditions can lead to a second wave in autumn (e.g. the degree of seasonality exceeding 0·30, or the daily rate of immunity loss exceeding 1% per day). Moreover, certain combinations of seasonality and mutation variables reproduced three-wave epidemic curves. Our results may offer insights to public health officials on how to predict the subsequent course of an epidemic or pandemic based on early and emerging viral and epidemic characteristics and what data may be important to gather.