bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transmission positron images and microscopes
Authors: Doyama Masao , Kogure Yoshiaki , Inoue Miyoshi , Kurihara Toshikazu , Matsuya Miyuki , Tsuno Katsushige , Yoshiie Toshimasa , Fujinami Masanori 
Published: August 2007

AbstractThe specifications of a transmission positron microscope constructing at KEK are presented. The microscope will be constructed by March 2009. Transmission positron images using imaging plates are shown. This method is quite useful and convenient to obtain positron images. Transmission images by electrons and positrons are compared. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Positron annihilation study of neutron irradiated pure Fe and Fe‐Cu binary alloys
Authors: Lambrecht M. , Jardin M. , Almazouzi A. 
Published: August 2007

AbstractThe hardening and embrittlement of Reactor Pressure Vessel (RPV) steels is of great concern in the actual nuclear power plant life assessment. This embrittlement is caused by irradiation‐induced damage, like vacancies, interstitials, solutes and their clusters. Fe‐Cu binary alloys are often used to mimic the behaviour of such steels. Their study allows identifying some of the defects responsible of the hardening, especially when compared to pure iron or C‐micro‐alloyed iron. Owing to their self‐seeking and selective trapping, positrons are used to determine the nature of these defects. Recently, at SCK·CEN, a new Positron Annihilation Spectroscopy (PAS) setup has been built, calibrated and optimized to measure the Coincidence Doppler Broadening (CDB) and Lifetime (LT) of neutron irradiated materials. This set‐up has been used to measure the CDB and LT of n‐irradiated pure Fe and Fe–Cu alloys. It is found that the clustering of Cu take place at the very early stages of irradiation using the CDB while LT measurement are showing much more vacancy clustering for low Cu alloys than in the higher ones. Increasing the neutron dose up to 1.3 × 1020 n/m2, allows the follow up of the kinetic of Cu and V‐clustering especially in Fe‐Cu alloys. It is found that both copper and carbon decrease the size of vacancy‐cluster, when added to iron. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Positron and positronium annihilation patterns in zeolites and bulk ceramics
Authors: Kajcsos Zs. , Kosanović C. , Liszkay L. , Major P. , Lohonyai L. , Zalán P. , Lázár K. , Bosnar S. , Subotić B. , Bosnar D. , Havancsák K. , Gordo P.M. , Tomašić N. 
Published: August 2007

AbstractPositron lifetime (LT) measurements have revealed that in porous media the annihilation pattern is probably dominated by a near‐saturation level trapping both for the positron and the positronium as well, which masks the contribution from the “free annihilation”, i.e., annihilation from delocalised positrons. In this work we compare positron lifetime spectra of crystalline zeolites with bulk ceramic materials fabricated by sintering from the same constituents as the zeolites and analyse common features and differences between them. For the dense ceramic samples the contribution from long‐living components to the annihilation pattern is substantially lower than that for the zeolites. The results are analysed with the aim to extract new knowledge for the zeolites and for the sensitivity limits for free volume studies in ceramics. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Positron annihilation induced Auger electron spectroscopy of Cu and Si
Authors: Mayer J. , Schreckenbach K. , Hugenschmidt C. 
Published: August 2007

AbstractPAES‐measurements on polycrystalline Cu, Si(100) and Cu coated Si(100) were performed at the intense positron source NEPOMUC in Munich. First results with considerably reduced electron background are presented. The surface sensitivity of PAES is shown and compared with conventional EAES. In addition, the measurement time could be reduced to three hours in order to observe the Cu M2,3VV‐Auger transition. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A novel time‐of‐flight spectrometer for PAES
Authors: Legl Stefan , Hugenschmidt Christoph 
Published: August 2007

AbstractPositron annihilation induced Auger electron spectroscopy (PAES) uses the annihilation of a positron with an electron of the inner shell of atoms whereas X‐rays or high‐energy electrons initiate the ionisation in conventional AES. Advantages of PAES are the extremely high surface sensitivity and the higher signal to noise ratio. In order to benefit from PAES one has to use a low‐energy positron beam of high intensity, which is available at NEPOMUC at the new Munich research reactor FRM‐II. The energy of the Auger electrons is mostly analysed by hemispherical energy analysers. Due to their small solid angle (typically ≥0.1%) and the necessity to scan over certain energy ranges in ≥1eV steps one still needs several hours using an intense positron source like NEPOMUC (at the FRM‐II) or even weeks at the lab‐beam based on a beta‐emitter to obtain an Auger spectrum. For this reason, a novel time‐of‐flight spectrometer (TOF‐PAES) was developed, which efficiently collects the Auger electrons emitted in a solid angle of 2π around the sample, and hence reduces the measurement time to less than one hour. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Defect characterization of CdTe thin films using a slow positron beam
Authors: Neretina S. , Grebennikov D. , Hughes R. A. , Weber M. , Lynn K. G. , Simpson P. J. , Preston J. S. , Mascher P. 
Published: August 2007

AbstractCadmium Telluride (CdTe) is the most well established II–VI compound largely due to its use as a photonic material. Existing applications, as well as those under consideration, are demanding increasingly stringent control of the material properties. The deposition of high quality thin films is of the utmost importance to such applications. In this regard, we present a report detailing the role of lattice mismatch in determining the film quality. Thin films were deposited on a wide variety of substrate materials using the pulsed laser deposition technique. Common to all substrates was the strong tendency towards the preferential alignment of CdTe's (111) planes parallel to the substrate's surface. X‐ray diffraction analysis, however, revealed that the crystalline quality varied dramatically depending upon the substrate used with the best results yielding a single crystal film. This tendency also manifested itself in the surface morphology with higher structural perfection yielding smoother surfaces. Slow positron beam techniques revealed a strong correlation between the defect concentration and the degree of structural perfection. Simulations of the data using the POSTRAP 5 program were used to calculate the defect concentration in relative (atom‐1) and absolute units and to determine the diffusion lengths of the positrons in the film. All of these characterization techniques point towards lattice mismatch as being the dominant mechanism in determining the quality of CdTe films. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Testing ETE model, temperature dependences of PALS data
Authors: Jasińska B. , Zaleski R. , Śniegocka M. , Reisfeld R. , Zigansky E. 
Published: August 2007

AbstractThree porous glasses produced by sol‐gel method were investigated using Positron annihilation lifetime spectroscopy (PALS) method. The theoretical curves calculated from the pick‐off annihilation model for cylindrical and spherical free volumes were compared to the results of PALS measurements done in the temperature range from 100 to 500 K. The o‐Ps mean lifetime values in the pores found in the experiment change with temperature in the glasses containing pores of R < 1.5 nm in the range up to 40 ns, while the model predicts these changes less then 10 ns. The meaningful discrepancy between experimental data and model predictions was found at low temperatures. The discrepancy diminishes with increasing pore sizes. In the glass containing the largest pores, R ∼ 2 nm, experimental values of o‐Ps lifetime agree well with model predictions. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spatially resolved defect studies on fatigued carbon steel
Authors: Eich P. , Haaks M. , Sindelar R. , Maier K. 
Published: August 2007

AbstractSeveral samples of the common ferritic tool steel AISI 1045 were fatigued in cyclic load tests. The local distribution of the Von‐Mieses stress σVM was simulated using the finite elements method (FEM). In the regions of interest, where σVM reaches maximum values, the defect distribution was measured spatially resolved by Doppler‐spectroscopy (DBAR) employing the Bonn Positron Microprobe (BPM). The lateral distribution of the S‐parameter, which could be described by a simple model derived from linear fracture mechanics, corresponds well with the simulated Von‐Mieses stress. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Positron lifetime calculations for stacking fault tetrahedra in copper
Authors: Van Petegem S. , Kuriplach J. , Derlet P. M. , Van Swygenhoven H. 
Published: August 2007

AbstractWe investigate the positron response of simulated stacking fault tetrahedra in Cu. We find that in both the regular and truncated stacking fault tetrahedra positron lifetimes are about 10‐15 ps larger than the bulk lifetime. This is an indication that the vacancy‐like defects observed in neutron irradiated Cu by positron annihilation lifetime measurements do not arise during the formation of the stacking fault tetrahedra but rather during the interaction of the stacking fault tetrahedra with other defects. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Zero field spin splitting in CdSe quantum dots
Authors: Supp D. , Slobodskyy T. , Slobodskyy A. , Gould C. , Schmidt G. , Molenkamp L. W. 
Published: August 2007

AbstractWe report the fabrication and characterization of self assembled CdSe quantum dots embedded in a dilute magnetic (Zn,Mn,Be)Se barrier. Transport experiments indicate a finite spin splitting at zero magnetic field although the materials are intrinsically paramagnetic. The result can be explained by the formation of a single magnetic polaron by ferromagnetic interaction between the surrounding Mn ions mediated by the carriers inside the dot. The effect prevails up to relatively high temperatures which we ascribe to a feedback mechanism induced by the tunneling current, previously predicted theoretically. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ion species dependence of the implantation‐induced defects in ZnO studied by a slow positron beam
Authors: Chen Z. Q. , Maekawa M. , Kawasuso A. , Naramoto H. 
Published: August 2007

AbstractIn this work, we implanted B+, O+, Al+, and P+ ions into ZnO with energy of 50‐380 keV and total doses of 4 × 1015 cm–2 for each ion. The implantation‐induced defects and their thermal recovery were studied using a slow positron beam. Vacancy clusters are produced in all the implanted samples. It is found that the thermal recovery of these vacancies induced by different ions shows much difference. In case of B+ and Al+‐implantation, the vacancy clusters agglomerate to much larger size and might evolve to microvoids during annealing. However, for O+ and P+ ions, which are heavier than B+ and Al+, the vacancies show a much weaker agglomeration process. The mechanism of such difference is discussed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The magic gold cluster Au20
Authors: Kryachko E. S. , Remacle F. 
Published: August 2007

AbstractThe 20‐nanogold cluster Au20 exhibits a large variety of two‐ and three‐dimensional isomeric forms. Among them is the ground‐state isomer Au20(Td) representing the stable cluster with a unique tetrahedral shape, with all atoms on the surface, and large HOMO‐LUMO gap which even slightly exceeds that of the buckyball fullerene C60. The anionic cluster Au(Td) that holds its parent tetrahedral symmetry features a high catalytic activity. The list of the properties of the 20‐nanogold clusters surveyed in the present work ranges from the energetic order of stability of its isomers to the optical absorption and excitation spectra of the Au20(Td) cluster. We also report the structures and properties of its doubly charged clusters Au and Au and computationally confirm that Au is indeed stable. The zero‐point‐energy‐corrected adiabatic second electron affinity of Au20(Td) amounts to 0.43–0.53 eV that is consistent with the experimental data. In addition, we provide computational evidence of the existence of the novel, hollow cage isomer of Au20 and analyze its key properties. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Mortality in Perforated Peptic Ulcer Patients After Selective Management of Stratified Poor Risk Cases
Authors: Rahman M. Mizanur , Islam M. Saiful , Flora Sabrina , Akhter S. Fariduddin , Hossain Shahid , Karim Fazlul 
Published: August 2007

AbstractIntroductionPerforated peptic ulcer disease continues to inflict high morbidity and mortality. Although patients can be stratified according to their surgical risk, optimal management has yet to be described. In this study we demonstrate a treatment option that improves the mortality among critically ill, poor risk patients with perforated peptic ulcer disease.MethodsIn our study, two series were retrospectively reviewed: group A patients (n = 522) were treated in a single surgical unit at the Dhaka Medical College Hospital, Dhaka, Bangladesh during the 1980s. Among them, 124 patients were stratified as poor risk based on age, delayed presentation, peritoneal contamination, and coexisting medical problems. These criteria were the basis for selecting a group of poor risk patients (n = 84) for minimal surgical intervention (percutaneous peritoneal drainage) out of a larger group of patients, group B (n = 785) treated at Khulna Medical College Hospital during the 1990s.ResultsIn group A, 479 patients underwent conventional operative management with an operative mortality of 8.97%. Among the 43 deaths, 24 patients were >60 years of age (55.8%), 12 patients had delayed presentation (27.9%), and 7 patients were in shock or had multiple coexisting medical problems (16.2%). In group B, 626 underwent conventional operative management, with 26 deaths at a mortality rate of 4.15%. Altogether, 84 patients were stratified as poor risk and were managed with minimal surgical intervention (percutaneous peritoneal drainage) followed by conservative treatment. Three of these patients died with an operative mortality of 3.5%.ConclusionsMinimal surgical intervention (percutaneous peritoneal drainage) can significantly lower the mortality rate among a selected group of critically ill, poor risk patients with perforated peptic ulcer disease.
RIGIDITY THEOREMS FOR HYPERSURFACES WITH CONSTANT SCALAR CURVATURE IN A UNIT SPHERE
Authors: WEI GUOXIN , SUH YOUNG JIN 
Published: August 2007

AbstractIn this paper, we give a characterization of Clifford tori $S^1(\sqrt{\textstyle\frac{nr+2-n}{nr}})\times S^{n-1}(\sqrt{\frac{n-2}{nr}})$ and $S^m(a)\times S^{n-m}(\sqrt{1-a^2}) (2 \le m \le n - 2, 0 \lt a^2 \lt 1)$ in a unit sphere Sn+1 (1). Our results extend the results due to Cheng and Yau [4], and Wang and Xia [11].
ESTIMATES FOR MARCINKIEWICZ INTEGRALS IN BMO AND CAMPANATO SPACES
Authors: HU GUOEN , MENG YAN , YANG DACHUN 
Published: August 2007

AbstractIn this paper, the authors consider the behavior on BMO($\mathbb R^n$) and Campanato spaces for the higher-dimensional Marcinkiewicz integral operator which is defined by
where Ω is homogeneous of degree zero, has mean value zero and is integrable on the unit sphere. Under certain weak regularity condition on Ω, the authors prove that if f belongs to BMO($\mathbb R^n$) or to a certain Campanato space, then [μΩ(f)]2 is either infinite everywhere or finite almost everywhere, and in the latter case, some kind of boundedness is also obtained. The corresponding Lusin area integral is also considered.
p-ADIC ORDER BOUNDED GROUP VALUATIONS ON ABELIAN GROUPS
Authors: KOCH ALAN , MALAGON AUDREY 
Published: August 2007

AbstractFor a fixed integereand primepwe construct thep-adic order bounded group valuations for a given abelian groupG. These valuations give Hopf orders inside the group ringKGwhereKis an extension of$\mathbb{Q} _{p}$with ramification indexe. The orders are given explicitly whenGis ap-group of orderporp2. An example is given whenGis not abelian.
AN INTERTWINING OPERATOR FOR THE GROUP B2
Authors: DUNKL CHARLES F. 
Published: August 2007

AbstractThere is a commutative algebra of differential-difference operators, acting on polynomials on $\mathbb{R}^{2}$, associated with the reflection group B2. This paper presents an integral transform which intertwines this algebra, allowing one free parameter, with the algebra of partial derivatives. The method of proof depends on properties of a certain class of balanced terminating hypergeometric series of 4F3-type. These properties are in the form of recurrence and contiguity relations and are proved herein.
Patterns of gene expression in schistosomes: localization by whole mountin situhybridization
Authors: DILLON G. P. , ILLES J. C. , ISAACS H. V. , WILSON R. A. 
Published: August 2007

SUMMARYAs a consequence of comprehensive transcriptome analysis followed by sequencing and draft assembly of the genome, the emphasis of schistosome research is shifting from the identification of genes to the characterization of their functions and interactions. Developmental biologists have long used whole mountin situhybridization (WISH) to determine gene expression patterns, as a vital tool for formulating and testing hypotheses about function. This paper describes the application of WISH to the study of gene expression in larval and adult schistosomes. Fixed worms were permeablized by proteinase K treatment for hybridization with digoxygenin-labelled RNA probes, with binding being detected by alkaline phosphatase-coupled anti-digoxygenin antibodies, and BM Purple substrate. Discrete staining patterns for the transcripts of the molecules Sm29, cathepsin L, antigen 10.3 and chorion were observed in the tegument cell bodies, gut epithelium, oesophageal gland and vitelline lobules, respectively, of adult worms. Transcripts of the molecules SGTP4, GP18-22 and cathepsin L were localized to tegument cell bodies and embryonic gut, respectively, of lung schistosomula. We also showed that Fast Red TR fluorescent substrate can refine the pattern of localization permitting use of confocal microscopy. We believe that method of WISH will find broad application, in synergy with other emerging post-genomic techniques, such as RNA interference, to studies focused at increasing our molecular understanding of schistosomes.
Part I. Analysis of data gaps pertaining to Salmonella enterica serotype Typhi infections in low and medium
human development index countries, 1984–2005
Authors: CRUMP J. A. , RAM P. K. , GUPTA S. K. , MILLER M. A. , MINTZ E. D. 
Published: August 2007

SUMMARYThere are only 10 contemporary, population-based studies of typhoid fever that
evaluate disease incidence using blood culture for confirmation of cases.
Reported incidence ranged from 13 to 976/100 000 persons per year.
These studies are likely to have been done preferentially in high- incidence
sites which makes generalization of data difficult. Only five of these studies
reported mortality. Of these the median (range) mortality
was 0%
(0–1·8%). Since study
conditions usually involved enhanced clinical management of patients and the
studies were not designed to evaluate mortality as an outcome, their usefulness
for generalizing case-fatality rates is uncertain. No contemporary
population-based studies reported rates of complications. Hospital-based typhoid
fever studies reported median (range) complication rates
of 2·8%
(0·6–4·9%) for
intestinal perforation and case-fatality rates of 2·0%
(0–14·8%). Rates of
complications other than intestinal perforation were not reported in
contemporary hospital-based studies. Hospital-based studies capture information
on the most severe illnesses among persons who have access to health-care
services limiting their generalizability. Only two studies have informed the
current understanding of typhoid fever age distribution curves. Extrapolation
from population-based studies suggests that most typhoid fever occurs among
young children in Asia. To reduce gaps in the current understanding of typhoid
fever incidence, complications, and case-fatality rate, large population-based
studies using blood culture confirmation of cases are needed in representative
sites, especially in low and medium human development index countries outside
Asia.
Eclipsing Binary Stars from Space
Authors: Bruntt Hans , Southworth John 
Published: August 2007

AbstractWe have begun a programme to obtain high-precision photometry of bright detached eclipsing binary (dEB) stars with the Wide-field InfraRed Explorer (WIRE) satellite (Bruntt & Buzasi 2006). Due to the small aperture of WIRE, only stars brighter than V = 6 can be observed. We are collecting data for about a dozen dEB targets and here we present preliminary results for three of them. We have chosen dEBs with primary components of B and early A type. One of our aims is to combine the information from the light curve analyses of the eclipses with asteroseismic information from analysis of the pulsation of the primary component.
Double Star Speckle Interferometry with the 3.5-m Telescope at Calar Alto (Almería, Spain)
Authors: Docobo J.A. , Tamazian V.S. , Andrade M. , Ling J.F. , Balega Y.Y. , Lahulla J.F. , Maximov A. , González–Romay J.R. 
Published: August 2007

AbstractThe first results of speckle interferometry carried out with the 3.5-m telescope of the C.A.H.A. (Almería, Spain) during a run in July, 2005 are presented. Forty nine stars with separations between 0″058 and 2″1 were observed under good seeing conditions. On the basis of these observations three improved orbits are presented. The Time Allocation Committee's report with a high scientific qualification to our proposal is included. It confirms the relevance of binary and multiple star research in modern astronomy and the great significance of large telescopes in this kind of studies as well.
CCD Astrometry and Photometry of Visual Double Stars: Northern Hipparcos Wide Pairs Measured in the Years 2003-2005
Authors: Sinachopoulos D. , Gavras P. , Medupe Th. , Ducourant Ch. , Dionatos O. 
Published: August 2007

AbstractThe relative positions of Hipparcos visual double star components are currently known with a precision around fifty mas. Modern CCD astrometric observations of these objects achieve an accuracy of their angular separation between ten and twenty mas per observation. New CCD measurements have been obtained at Kryonerion Observatory in the north hemisphere. They provide current relative positions of visual double stars which are at least twice as accurate as the ones provided by Hipparcos. The new measurements will permit us to extract the physical pairs from the sample, and the double stars, which have components of common origin. Final statistics of these systems will improve our understanding of stellar formation and evolution rates of wide binaries in the solar neighborhood.
Starspot Activity of V711 Tau from November to December 2005
Authors: Gu Sheng-hong , Cameron Andrew Collier , Barnes J.R. , Yang Jia-yan 
Published: August 2007

AbstractTwo new high-resolution spectroscopic datasets of the active binary V711 Tau are analyzed here. Using the Least-Squares Deconvolution method, we have derived the time series profiles of V711 Tau with high signal-to-noise ratio, which have been used to reconstruct the starspot patterns for its two components by means of the Doppler imaging code DoTS. The results show that the high latitude spots are main features for the primary, the low latitude spots are clear for the secondary in both of two observing runs, and the starspot pattern changes obviously during one month. The lifetime of intermediate-low latitude spots is shorter than the high latitude spots for the primary, the low latitude spots of the secondary seem to have a longer lifetime.