bluuebunny/crossref_metadata_2025 huggingface dataset:
Multiproxy late Holocene peat records from Ireland: towards a regional palaeoclimate curve
Authors: Blundell Antony , Charman Dan J. , Barber Keith
Published: August 2007

Two new peat‐based climate records from Ireland covering the late Holocene are presented. The sequences are dated by a strong chronological framework formed by AMS radiocarbon dates and SCPs. Three proxy indicators (testate amoebae, macrofossils and humification) have been determined allowing the limitations and strengths of each to be identified and utilised to provide a bog surface wetness (BSW) record for both sites. Age–depth models take into account the potential for accumulation rates to vary with bog vegetation. The records from each site have been used to derive a combined BSW record that displays changes to a wetter/cooler climate from ca. AD 30 (1920 BP), ca. AD 310 (1640 BP), ca. AD 805 (1145 BP), ca. AD 1040 (910 BP) and ca. AD 1300 (650 BP). Changes follow closely those identified in a northern Britain composite BSW record and largely correspond with lake‐level data in central France suggesting the main changes in water balance were coherent over a large region. Correspondence with increases in IRD and slower Iceland‐Scotland Overflow Water (ISOW) suggests that these changes were related to oceanic forcing influencing the track of dominant westerly air flow over Ireland. Copyright © 2007 John Wiley & Sons, Ltd.
Relative surface age‐dating of rock glacier systems near Hólar in Hjaltadalur, northern Iceland
Authors: Kellerer‐Pirklbauer Andreas , Wangensteen Bjørn , Farbrot Herman , Etzelmüller Bernd
Published: August 2007

Schmidt‐hammer rebound values and photogrammetric measurements of surface displacement were used to date two active polymorphic (high‐altitude) and two relict monomorphic (low‐altitude) rock glaciers near Hólar in Hjaltadalur, Tröllaskagi peninsula, northern Iceland (65° 40′ N, 19° 00′ W). Both low‐altitude rock glaciers are of Late Weichselian or Preboreal origin (ca. 10.3–9.2 k yr BP) with minor later reshaping until the early Neoglacial period (‘Vatnsdalur I’; ca. 5.2 k yr BP). Both high‐altitude rock glaciers consist of an upper lobe overriding a lower lobe corresponding to initiation during different cool phases. The initiation of the lower lobes can possibly be attributed to the ‘GH‐8.2 event’ (8.6–8.0 k cal. yr BP). They reached their terminal position at the end of the ‘Vatnsdalur I’ stage. The upper lobes of the high‐altitude rock glaciers were initiated sometimes between the ‘Vatnsdalur I’ but substantially before the ‘Vatnsdalur II’ (ca. 3.0–3.2 k yr BP) stages and underwent modification during each following Holocene glacier expansion episode, culminating the last time in the Little Ice Age. Thus, it is suggested that similar looking rock glaciers occurring elsewhere in the Tröllaskagi peninsula may have a similar complex history. Therefore, they may not be seen as rather simple landforms developed during the Little Ice Age. Copyright © 2007 John Wiley & Sons, Ltd.
A Study of Simple RAFT Transfer Agents for the Polymerization of (Meth‐)acrylates and Acrylamides
Authors: Seifert Denis , Kipping Martin , Adler Hans‐Jurgen P. , Kuckling Dirk
Published: August 2007

Summary: Within this work we aimed to study different RAFT agents for the potential use in coupled block copolymerization. Starting from S‐(thiobenzoyl)thioglycolic acid as a commercial available CTA it should easily be possible to modify the substituent due to the thiocarboxylic group. Different chain transfer agents CTA's were synthesized and RAFT polymerizations of methyl methacrylate, butyl acrylate, N,N‐dimethyl acrylamide, N,N‐diethyl acrylamide, and N‐isopropyl acrylamide were carried out and compared with each other.
A coupled damage–plasticity model for concrete based on thermodynamic principles: Part II: non‐local regularization and numerical implementation
Authors: Nguyen Giang D. , Houlsby Guy T.
Published: August 2007

Non‐local regularization is applied to a new coupled damage–plasticity model (Int. J. Numer. Anal. Meth. Geomech. 2007; DOI: 10.1002/nag.627), turning it into a non‐local model. This procedure resolves softening‐related problems encountered in local constitutive models when dealing with softening materials. The parameter identification of the new non‐local coupled damage–plasticity model is addressed, with all parameters being shown to be obtainable from the experimental data on concrete. Because of the appearance of non‐local spatial integrals in the constitutive equations, a new implementation scheme is developed for the integration of the non‐local incremental constitutive equations in nonlinear finite element analysis. The performance of the non‐local model is assessed against a range of two‐dimensional structural tests on concrete, illustrating the stability of the stress update procedure and the lack of mesh dependency of the model. Copyright © 2007 John Wiley & Sons, Ltd.
Introducing practice development in a Cheshire home
Authors: Harwood Karen , Baldwin Kathleen , Letts Jo , Earl Anthony
Published: August 2007

The opportunity taken in 2001 by St Cecilia's, a Leonard Cheshire Home for the physically disabled, to set up a working group under a programme for practice development has produced significant changes in routines and style of management, and has fostered several initiatives from all levels of the community. Staff at all levels, service users and volunteers (often without any health care background) have collaborated to introduce changes in delivery of care, quality of life, communication techniques, and education and training procedures. Accreditation has encouraged the personnel of the home to plan further measures that will respond to the needs and desires of their residents. Copyright © 2007 John Wiley & Sons, Ltd.
Numerical simulation of anisotropic elastic fields of a GaAs/GaAs twist boundary
Authors: Madani Salah , Outtas Toufik , Adami Lahbib
Published: August 2007

Self‐assembled nanostructures are particularly interesting for optoelectronic and photonic applications, especially on silicon and GaAs substrates. Nevertheless, their long‐range spatial distribution is random, their density is difficult to control, their size distribution can be large and their shapes can be different. By overcoming these drawbacks, it should be possible to improve the performances of existing devices or to fabricate new ones. This work studies the possibility to order on a long range self‐assembled nanostructures on a GaAs substrate, by means of the elastic fields induced at the surface by shallowly buried periodic dislocation networks. The needed strain and stress fields, generated by a square network of screw dislocations located between a finite layer of GaAs bonded onto a semi‐infinite GaAs substrate, are calculated using anisotropic elasticity. The results obtained are compared to those obtained using isotropic elasticity. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Vertically self‐aligned conical carbon nanofibers by pulsed discharge plasma chemical vapour deposition and its field electron emission
Authors: Somani Prakash R. , Somani Savita P. , Yoshida A. , Suzeki T. , Noda M. , Tanemura M. , Lau S. P. , Umeno M.
Published: August 2007

Vertically self‐aligned conical carbon nanofibers were deposited on silicon coated with thin film of cobalt (100 nm) using pulsed discharge plasma chemical vapor deposition at 400–450 °C. Possible mechanism of their growth is discussed. FE‐SEM observations indicate that they are self vertically well aligned, with an average diameter of about 200 nm at the bottom and with a tip of about 70 to 100 nm in diameter. HR‐TEM, visible Raman and XRD study reveals that the nanofibers have an amorphous structure and are made of diamond like carbon. Field electron emission study indicates a low turn‐on field of about 1.4 V/μm and threshold field of about 4.2 V/μm, suggesting their possible application as field electron emitters. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nanoparticles of SmBa2HfO5.5 through a single step auto‐igniting combustion technique and their characterization
Authors: Thomas J. K. , Padma Kumar H. , Solomon S. , George Chandy N. , Joy K. , Koshy J.
Published: August 2007

Samarium Barium Hafnium oxide (SmBa2HfO5.5), a complex perovskite ceramic, was synthesized as nano‐ particles for the first time using an auto‐igniting combustion technique. Phase‐purity and particulate properties of the as‐prepared powder were studied using X‐ray diffraction, differential thermal and thermo gravimetric analyses, Fourier‐transform of infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and electron diffraction techniques. The X‐ray diffraction and electron diffraction studies have shown that the as‐prepared powder was single phase, crystalline, and has a complex cubic perovskite structure (A2BB′O6) with a lattice constant a = 8.330 Å. The particle size calculated from FWHM is about 15 nm. The transmission electron microscopic investigation has shown that the particle size of the as‐prepared powder was in the range 20–30 nm with a mean grain size of 25 nm. The nano‐ particles of SmBa2HfO5.5 obtained by the present method could be sintered to 99% of its theoretical density at 1600 °C. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Polydiacetylene‐based selective NH3 gas sensor using Sc2O3/GaN structures
Authors: Lee G. S. , Lee C. , Choi H. , Ahn D. J. , Kim J. , Gila B. P. , Abernathy C. R. , Pearton S. J. , Ren F.
Published: August 2007

PDA(Polydiacetylene)‐supramolecules were successfully immobilized on the surface of Sc2O3/GaN/Sapphire structures for use as selective NH3 gas sensors. The Sc2O3 was epitaxially grown on GaN/Sapphire templates by molecular beam epitaxy (MBE) to replace the non‐uniform native Ga2O3. The GaN‐based PDA gas sensors showed excellent selectivity for ammonia detection after the end‐functional group was modified to respond to this specific gas species. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical planar waveguides in Nd:YLiF4 crystal fabricated by proton implantation
Authors: Tan Yang , Chen Feng , Wang Lei , Lu Qing‐Ming
Published: August 2007

An optical planar waveguide has been fabricated in Nd:YLiF4 crystal by means of proton implantation at an energy of 500 keV. The m ‐line arrangement was used to obtain the dark‐line spectra of the sample. The induced optical barrier with lower refractive indices inside the crystal confined the near‐surface region of the sample as waveguide structures. The waveguide remained fairly stable under thermal annealing treatment at 340 °C for 60 min in air. The nuclear damage created by the incident protons inside the crystal was considered to be the main cause of the barrier formation. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
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

The 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

The 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

Positron 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

PAES‐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

Positron 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

Cadmium 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

Three 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

Several 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

We 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

We 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

In 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

The 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

Introduction

Perforated 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.

Methods

In 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.

Results

In 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%.

Conclusions

Minimal 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

In 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

In 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

For 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

There 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

As 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.
Automatic Identification System (AIS): Data Reliability and Human Error Implications
Authors: Harati-Mokhtari Abbas , Wall Alan , Brooks Philip , Wang Jin
Published: August 2007

This paper examines the recent introduction of the AIS to the ship's bridge and its potential impact on the safety of marine navigation. Research has shown that 80 to 85% of all recorded maritime accidents are directly due to human error or associated with human error. Safety is an important element of marine navigation and many people at different levels are involved in its management. The safe and efficient performance of joint systems, is heavily dependent upon how functions are allocated between the human and the machine. This paper investigates different regulations, supervision for proper use, training, and management of AIS users. It uses previous research and three separate AIS studies to identify problems. The potential of the AIS to cause problems is analysed. The classic human factor “Swiss Cheese” Model of system failure has been modified for the AIS to investigate a possible accident trajectory. The paper then concludes with recommendations and suggestions for improvements and further work.
A Numerical Approach to GPS Satellite Perturbed Orbit Computation
Authors: Cojocaru Stelian
Published: August 2007

This paper proposes a numerical algorithm designed to integrate the GPS satellite perturbed orbit. The numerical solution is applied to integrate the differential equation of perturbed motion that frames the significant perturbing accelerations. Perturbing potentials are given and the corresponding accelerations in Cartesian coordinates are subsequently deduced. The C++ program that implements a fourth-order Runge-Kutta algorithm is described and comment is made on the perturbed orbit integration results. The paper offers a set of conclusions that will hopefully create a quantitative and qualitative image of GPS orbital perturbations and open a few ways ahead.
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

There 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

We 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.
Analytical Binary Modeling and its Role in Dynamics
Authors: Chatterjee Tapan K.
Published: August 2007

Binaries are critical tools that drive stellar systems; which play a major role in galactic dynamics. Internal evolution of globular clusters, e.g., due to evolution of binaries, can be modulated by external effects, like tidal shocks (e.g., Chernoff & Weinberg 1990). There are well-established relations between dynamical properties of globular clusters and their galactrocentric distance, R(g). A characteristic one is: D(1/2) ≈ [R(g)]1/2, where D(1/2) is the diameter containing half the mass / luminosity in projection (van den Bergh et al. 1991). This relation could be a result of tidal evaporation of clusters and feedback of forming protoclusters (Surdin, 1995). A similar limitation of globular cluster distributions is obtained in the half-mass density kinetic temperature plot and used in many cluster formation scenarios (Muray & Lin 1992). This relationship should have an explanation on the basis of dynamic evolution of the cluster population.
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

The 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

The 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.
Duplicity Among λ Boo Stars: the New Case of HD 204041
Authors: Gerbaldi M. , Faraggiana R.
Published: August 2007

The spectrum of the classical λ Boo star HD 204041 is revealed to be a composite one.
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

Two 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.
J-, H-, and K-band Spectra of Three SU UMa-Type Dwarf Novae
Authors: Ishioka Ryoko , Sekiguchi Kazuhiro , Maehara Hiroyuki
Published: August 2007

We present the results of J-, H-, and K-band spectroscopy on three SU UMa-type dwarf novae with orbital periods of 1.33 – 1.37 hr. We performed the SED fitting for the obtained spectra by assuming a power-law distribution for the accretion disk and using template spectra of late-type dwarfs for secondary star. ASAS 002511+1217.2 and EQ J183926+260409 are WZ Sge-type or WX Cet-type dwarf novae. We found strong water absorption features in their spectra, which are characteristic in late M- or L-type dwarfs. The SED fitting suggests that their secondary contributions to the overall SED are less than one third. We identified the secondary stars as M9 and L1 type dwarfs, which are rather less massive but still normal stars. The spectrum of SDSS J013701−091235 is dominated by the secondary component. Spectral features of this object are similar to those of an early M-type dwarf in spite of its short orbital period. The spectrum of SDSS 0137 strongly suggests that the evolutionary path of this object is different from that of ordinary CVs, and this object is a candidate of EI Psc-like systems.
Statistical Modeling and Analysis of Wide Binary Star Systems
Authors: Johnston K.B. , Oswalt T.D. , Valls-Gabaud D.
Published: August 2007

Post-main-sequence (MS) mass loss causes orbital separation amplification in fragile (i.e. common proper motion) binary star systems. Components typically have separations around ∼1000 AU. Such wide pairs experience negligible tidal interactions and mass transfer between companions; thus they evolve as two separate but coeval stars. In this paper we compute the rate of mass loss during the components' lifetimes and attempt to model how it will statistically distort a frequency distribution of fragile binary separations. Understanding this process provides a robust test of current theories of stellar evolution and sets constraints on the dynamics of the Galactic disk.
The Orbit of T Tauri South
Authors: Köhler Rainer , Ratzka Thorsten
Published: August 2007

We report on previously unpublished diffraction-limited NIR observations of the young binary star T Tauri South. Orbital elements have been estimated by a least–squares fit to the relative positions. Although the parameters are not well constrained by the observations, we can derive a minimum system mass of about 3 M⊙.

With the most recent astrometric measurements by Duchêneet al. (2006), hyperbolic (unbound) orbits can be excluded with high confidence. We conclude that T Tauri Sb isnotin the process of being ejected from the system.
Hunt for Binaries with Pulsating Components
Authors: Latković Olivera
Published: August 2007

In the frame of the collaboration of several Southern European observatories, we are examining a number of eclipsing binary systems in search for evidence of pulsating phenomena. We hope our candidate systems will be suitable for subsequent astroseismological studies. As a first step towards this end, we are analyzing spectroscopic observations of several such binary stars; these observations have been made at the National Astronomical Observatory Rozhen, Bulgaria, in the period from 2002 to 2005, and the reduction was done at the Astronomical Observatory of Belgrade, Serbia. The measurements of radial velocities and RV curve analysis are in preparation.
The Multiple System SZ Cam
Authors: Michalska Gabriela , Kubát Jiří , Korčáková Daniela , Kawka Adéla , Ceniga Michal , Kučerová Blanka , Votruba Viktor
Published: August 2007

The multiple stellar system SZ Cam is solved using the method of spectral disentrangling. Hα line profiles of three components are obtained and spectroscopic orbit elements are redetermined.
EUVE J0825-16.3 and EUVE J1501-43.6: Two dMe Double–Lined Spectroscopic Binaries
Authors: Montes D. , Crespo-Chacón I. , Gálvez M.C. , Fernández-Figueroa M.J.
Published: August 2007

High-resolution echelle spectroscopic observations taken with the FEROS spectrograph at the ESO 2.2-m telescope confirm the binary nature of the dMe stars EUVE J0825−16.3 and EUVE J1501−43.6, previously reported by Christian & Mathioudakis (2002). In these binary systems, emission of similar intensity from both components is detected in the Na i D1 & D2, He i D3, Ca II H&K, Ca II IRT and Balmer lines. We have determined precise radial velocities by cross-correlation with radial velocity standard stars, which have allowed us to obtain for the first time the orbital solution of these systems. Both binaries consist of two nearly equal M0V components with an orbital period shorter than 3.5 days. We have analyzed the behaviour of the chromospheric activity indicators (variability and possible flares). In addition, we have determined its rotational velocity and kinematics.
On the Evolutionary History of Progenitors of EHBs and Related Binary Systems from their Observed Properties
Authors: Pustynski V.V. , Pustylnik I.
Published: August 2007

It has been shown quite recently (Morales-Rueda et al. 2003) that dB stars, extreme horizontal branch (EHB) objects in high probability all belong to binary systems. We study in detail the mass and angular momentum loss from the giant progenitors of sdB stars in an attempt to clarify why binarity must be a crucial factor in producing EHB objects. Assuming that the progenitors of EHB objects belong to binaries with initial separations of a roughly a hundred solar radii and fill in their critical Roche lobes while close to the tip of red giant branch, we have found that considerable shrinkage of the orbit can be achieved due to a combined effect of angular momentum loss from the red giant and appreciable accretion on its low mass companion on the hydrodynamical timescale of the donor, resulting in formation of helium WD with masses roughly equal to a half solar mass and thus evading the common envelope stage. A simple approximative analytical formula for mass loss rate from Roche lobe filling giant donor has been proposed depending on mass, luminosity and radius of donor.
Hydrodynamic Simulations of Irradiated Secondary Stars in Dwarf Novae
Authors: Viallet M. , Hameury J.H.
Published: August 2007

We investigate the possibility of a mass transfer enhancement during outburst in dwarf novae. We present here the first two-dimensional hydrodynamic simulations of the surface flows in the secondary, driven by the strong inhomogenous heating of the atmosphere during an outburst. We also discuss the possibility that the direct heating of the L1 point by the disc rim contributes to the mass transfer enhancement.
BVRI Light Curves and Period Analysis of the Beta Lyrae System XX Leonis
Authors: Zasche P. , Svoboda P. , Wolf M.
Published: August 2007

The contact eclipsing binary system XX Leonis (p = 0.97 days, Sp A9) has been analysed using the PHOEBE programme, based on the Wilson–Devinney code. The BVRI light curves were obtained during spring 2006 using the 20-cm telescope and ST-7 CCD detector. The effective temperature of the primary component determined from the photometric analysis is T = (7342 ± 14) K, the inclination of the orbit is i = (84.83 ± 0.29)° and the photometric mass ratio q = (0.40 ± 0.01). The third-body hypothesis was also suggested; based on a period analysis using 57 minimum times this gave a period for the third body of p3 = (59.66 ± 0.05) yr, an amplitude of A = (0.036 ± 0.028) day and zero eccentricity, which yields as a minimum mass M3,min = (0.91 ± 0.01) M⊙.
The Remarkable Eclipsing Binary TW Draconis
Authors: Zejda M. , Mikulášek Z. , Wolf M. , Svoboda P.
Published: August 2007

We analyzed a new photometry of this well-known Algol-like eclipsing binary together with old photoelectric measurements with the aim of better understanding of its orbital period changes and short-time light variations modulating the mean light curve. The analysis has been done by the new method based on the combination of the principal component analysis and robust regression. New spectroscopic observations and radial-velocity curve are also presented.
TWAN: A way of networking third-world astronomers
Authors: Narlikar Jayant V.
Published: August 2007

This talk describes a proposal to set up a series of international institutions in different parts of the world to serve as nodes in a network that links astronomers from the developing nations worldwide. This network, along with its nodes is visualized as an economic way of upgrading the facilities for teaching, research and development of astronomy in the Third World countries. By way of illustration, the modus-operandi of the Inter-University Centre for Astronomy and Astrophysics in Pune, India is described. A network of this kind is suggested as a cost-efficient way of sharing limited resources.
Formal education in astronomy in Latin America
Authors: Levato Hugo
Published: August 2007

We review the present situation of the formal education in astronomy in the Latin American countries. We have concluded that we can divide the countries into three categories according with the different development of the astronomical careers in astronomy.
Astronomy in Colombia
Authors: Cepeda-Peña William E.
Published: August 2007

Astronomy in Colombia has been done since the beginning of the nineteenth century, when in 1803 one of the oldest (or maybe the oldest) astronomical observatories of America was built. This is a very beautiful, historical and ancient building. A small dome with a small telescope is also inside the university campus. The observatory marks since then the development of astronomy in Colombia as a professional science. At the present time a Master's programme and a Specialization programme are successfully carried out with a good number of smart young students. The observatory has a staff of eleven professors, all with a master's degree in sciences; two of them have a PhD and in a couple of years five staff members will have a PhD in physics. With some international collaboration, they will introduce in a few years a doctoral astronomical program. There are several research lines mainly in the fields of astrometry, Galactic and extragalactic astronomy, cosmology, astro-statistics and astrobiology. Three research groups have got recognition from the governmental institution that supports the research in sciences COLCIENCIAS. Several papers have been published in national and international journals. Besides the professional line in astronomy, the observatory sponsors several non-professional Colombian astronomical groups that work enthusiastically in the field of astronomy.