bluuebunny/crossref_metadata_2025 huggingface dataset:
Problem Solving with the TOPAS Macro Language: Corrections and Constraints in Simulated Annealing and Rietveld Refinement
Authors: Whitfield Pamela S. , Davidson Isobel J. , Mitchell Lyndon D. , Wilson Sasha , Mills Stuart J.
Published: June 2010

The TOPAS macro language can be a powerful tool for increasing the capabilities of X-ray powder diffraction analysis. New corrections and constraints can be implemented without altering the program's code, allowing for experimentation with new ideas and approaches. Examples are given, exposing the power and flexibility of the macro language to help solving problems with a few lines of code. The use of simulated annealing for structure solution of an organic material from data exhibiting preferential orientation is one example. Another one is about extraction of useful structural information in Rietveld refinement of natural hydrotalcite-group minerals, a problematic case that would normally be regarded as over-parameterized for the data available.
First Results from the VULCAN Diffractometer at the SNS
Authors: Wang X.L. , Holden Thomas , Stoica A.D. , An K. , Skorpenske H.D. , Jones A.B. , Rennich G.Q. , Iverson E.B.
Published: June 2010

On Friday June 26, 2009, the neutron beam shutter for the VULCAN diffractometer at the SNS was opened for the first time. Initial measurements to characterize the instrument performance are reported. It is shown that the measurement results are by and large in agreement with design calculations. New research opportunities with VULCAN are discussed.
Size and Strain Analysis of Deformation Microstructure in High-Nitrogen Austenitic Stainless Steels
Authors: Lee Tae Ho , Shin Eun Joo , Ha Heon Young , Oh Chang Seok , Kim Sung Joon
Published: June 2010

Deformation microstructure of Fe-18Cr-10Mn alloys with different nitrogen content (0.39 and 0.69N) were investigated using neutron diffraction. The deformation mode changed from strain-induced martensitic transformation (SIMT) to deformation twinning (DT), as nitrogen content was increased. The measured neutron profiles of tensile-strained bulk samples were fitted by modified Thomson-Cox-Hasting profile-shape function and the Lorentzian and Gaussian integral breadths were calculated based on Rietveld refinement. With the calculated integral breadths, the mean-squared (MS) strain could be evaluated using the size and strain analysis of double-Voigt approach. Based on the analysis of peak shift of individual reflections, the stacking fault probability (SFP) was determined. Although the calculated SFP and MS strain varied with the degree of deformation, the ratio of MS strain to SFP remained constant for each alloys regardless of tensile strain, but increased with nitrogen content. As a result, it was found that the SFE increased with increasing nitrogen content. The nitrogen-induced transition of deformation microstructure was accounted for by the change in SFE, as reported in other fcc materials.
The Deformation of Face-Centred-Cubic Metals Measured by Diffraction Peak Profile Analysis
Authors: Simm Thomas. H. , Withers Philip J. , Ungár Tamás , Fonseca J.
Published: June 2010

Uniaxial deformed fcc metal samples have been studied by diffraction peak profile analysis. A method that can explain changes in broadening of different peaks by use of a Taylor model has been investigated. It was found that the method qualitatively describes the changes in broadening in nickel and stainless steel samples. It is argued that the differences between predictions and measurements are a feature of how the different samples deform at the microstructural scale.
Stress Estimation of Titanium Casting Alloy by X-Ray Measurement Technique of Single Crystal
Authors: Masayuki Nishida , Takao Hanabusa , Shiro Ayumi , Matsue Tatsuya
Published: June 2010

Residual stresses in titanium casting alloy were estimated by X-ray stress measurement technique. There are two problems in the condition of X-ray stress measurement. Firstly, the titanium casting alloy has the large crystal grains. These coarse grains were generated under solidification processes and those sizes are approximately 2 millimeter in this study. These coarse crystal grains interfere with an accurate stress measurement due to the unstable diffraction profile [1]. This is because the existence of a sufficient number of isotropic crystal grains in the X-ray irradiation area are based on the X-ray diffraction theory. In this study, the stress measurement technique of single crystal materials was adopted for the solution of this fundamental problem [2, 3]. Because the coarse crystal grain was treated as a single crystal, the high intensity diffraction profiles were observed from a certain direction with investigations of crystal orientation. The problem with the coarse crystal grain in titanium casting alloy were cleaned up by the employment of the single crystal measurement technique. Secondly, the results from this study show that the position of crystal grain within the X-ray irradiation area greatly influenced the residual stress values. Therefore, in the present paper the erasing method of this position effect was tried and discussed [4]. Finally, the improvement of the accuracy of this method for the residual stress measurement in titanium casting alloy under the several bending stresses was confirmed. These results show that the erasing method in this study is an effective correction method.
Combined In Situ Neutron Diffraction and Acoustic Emission of Twin Nucleation & Twin Growth in Extruded ZM20 Mg Alloy
Authors: Muránsky Ondrej , Barnett Matthew R. , Carr David G. , Vogel Sven C. , Oliver E.C.
Published: June 2010

In the present work in situ neutron diffraction and acoustic emission were used concurrently to study deformation twinning in two ZM20 Mg alloys with significantly different grain sizes at room temperature. The combination of these techniques allows differentionation between the twin nucleation and the twin growth mechanisms. It is shown, that yielding and immediate post-yielding plasticity in compression is governed primarily by twin nucleation, whereas the plasticity at higher strains is governed by twin growth. The current results further suggest that yielding by twinning happens in a slightly different manner in the fine-grained as compared to the coarse-grained alloy.
Strain Measurement of Aged Duplex Stainless Steel Using SR White X-Rays
Authors: Kiriyama Koji , Shobu Takahisa , Shibano Junichi , Fujishiro Tomoyuki , Kaneko Hiroshi , Miura Setsuo
Published: June 2010

Duplex stainless steels (DSSs) have microstructures of α and γ-phases of iron and exhibit changing of their mechanical properties by aging above 300°C, so that strain behavior is expected to be complicated under stress loading. In order to estimate lattice strains and to determine their behavior, lattice strain measurements of aged DSSs have been performed using synchrotron radiation white X-rays. As a result, it was found that the lattice strain was not always correspond with applied macro strain, and the lattice strains of γ-phase showed no elongation in comparison with those of α-phase in the aged specimen. These results mean that complex strain distributions between (hkl) planes already exist in the early stage of elastic deformation, and suggest that fracturing of aged DSSs under tensile loading occurs preferentially on γ-phase rather than α-phase.
Non Destructive Characterization of Phase Distribution and Residual Strain/Stress Map of Two Ancient (Koto) Age Japanese Swords
Authors: Grazzi Francesco , Bartoli Laura , Civita Francesco , Paradowska Anna Maria , Scherillo Antonella , Zoppi Marco
Published: June 2010

Two Japanese long swords (katanas) belonging to the Koto Age (X-XVI century A.D.) were measured through time of flight neutron diffraction to analyze the phases, and the stress and strain distribution, in selected parts of the blades. The swords are representative of two different forging schools (Aoe and Kanesada) and one of the main aims of the measurements was to evidence possible similarities and differences.
Two independent experiments were carried out at the ISIS pulsed neutron source using the INES and ENGIN-X diffractometers. The former was employed to map the average phase distribution on two selected cross sections, of each blade, distinguishing among the ridge, the core, and the edge of the blades. In this way, we were able to quantify the coarse distribution of the carbon content and, moreover, we could evidence the presence of martensite. These data were then complemented measuring detailed stress and strain distribution maps on ENGIN-X. As far as the ridge and the core are concerned, the tang data were taken as a reference.
These measurements significantly improve the knowledge and understanding of the technology used to produce Japanese swords belonging to the Koto Age.
The Use of Diffraction to Study Fatigue Crack Tip Mechanics
Authors: Kelleher Joe F. , Lopez-Crespo Pablo , Yusof Feizal , Withers Philip J.
Published: June 2010

Simple experimental tests of fatigue life are often insufficient to characterise fatigue behaviour. Fatigue crack growth in polycrystalline metals is governed by a number of interacting mechanical effects at the crack tip, such as the deformation inside a plastic zone and contact between the crack faces over part of the loading cycle. Typically, results tend to be interpreted in terms of an empirical fatigue law such as the Paris equation, which in itself fails to generalise to different load ratios or multiaxial load cases. While extensions to this equation have been used, these are mostly empirical and do little to enhance understanding of the fatigue growth mechanisms. Recently, the use of diffraction to characterise crack tip stress effects has become increasingly popular. In this paper, we consider the opportunities and the difficulties associated with making such measurements by neutron and synchrotron diffraction. In particular we examine grain size effects, plane stress/plane strain issues, optimisation of the gauge geometry, measurement of the plastic zone and crack closure effects.
Tensile Deformation Behaviors of Metastable Austenitic Stainless Steels Studied by Neutron Diffraction
Authors: Tsuchida Noriyuki , Fukaura Kenzo , Tomota Yo , Moriai Atsushi , Suzuki Hiroshi
Published: June 2010

Tensile deformation behaviors of three austenitic stainless steels, JIS-SUS310S, 304 and 301L, were studied by static tensile tests and in situ neutron diffraction. In the mechanical properties obtained by the static tensile tests, the 304 and 301L steels showed better balance of tensile strength and uniform elongation than the 310S one because of TRIP effect. The angular dispersion neutron diffractions with a wavelength of 0.16 or 0.182 nm were performed during stepwise tensile testing by using a neutron diffractometer for residual stress analysis (RESA) at the Japan Atomic Energy Agency. The lattice plane strain, stress-induced martensite volume fraction, dislocation density and so on were estimated by the profile analysis as a function of applied stress. The change in lattice plane spacing for austenite indicated four deformation stages. In the comparison of lattice plane strain among the tested steels, a phase stress caused by the stress-induced martensite seems to overlap the intergranular stress of austenite phase. Judging from the results of profile analysis, the strain partitioning of austenite phase in metastable austenitic steels became larger with increasing of the volume fraction of stress-induced martensite during tensile deformation.
Applied Stress on Silicon Perfect Single Crystal for Controlling the Extinction Layer
Authors: Muslih M.Refai , Ridwan  , Kuntoro Iman , Minakawa Nobuaki
Published: June 2010

The extinct layer of Si(311) perfect single crystal has been investigated by neutron diffraction method with the residual stress diffractometer DN1-M installed at the experimental hall of Indonesian multipurpose reactor RSG-GAS, in Serpong, which provides micro beam and point detector arrangement. A Si(311) perfect single crystal with thickness of 5mm was used in this experiment. The crystal was finely polished at one side and roughly polished at the opposite one. It was measured that diffracted beam from the finely polished side shows very low intensity with narrow peak profile, while for the roughly polished surface, shows stronger and broaden peak. The diffraction layer of rough surface was determined to be 0.36mm, while the smooth one was 0.28mm. It was also found that in the direction of crystal thickness in between layers no diffraction peak was detected.
By these experiments it was confirmed that the applied stress on Si(311) perfect single crystal produced thicker diffraction layer. This technique is one that can be used in order to enhance the total diffracted neutron, which is desired to produce a good monochromator system.
Residual Stress Measurements in Large Scale Component Sections
Authors: Davies Catrin Mair , Wimpory Robert C. , Paradowska Anna Maria , Nikbin Kamran M.
Published: June 2010

Neutron diffractometer Engin-X at ISIS was used use in this study to investigate the residual stresses in a section of a multi-pass girth welded thick pipe, of nominal thickness 62 mm, which was made of a ferritic-martensitic steel denoted type P92. Measurements in such large component sections are rare, and have driven the neutron diffraction method to the edge of its capabilities. Significant stresses of over 150 MPa have been found in this pipe section, though post weld heat treatment has been performed. The influences of these welding residual stresses in components at operating temperatures are discussed in terms of their relaxation and high temperature fracture behaviour.
Residual Microstress of Austenitic Stainless Steel Due to Tensile Deformation
Authors: Suzuki Kenji , Shobu Takahisa
Published: June 2010

Material of the specimen was austenitic stainless steel (SUS316L). The specimens were given tensile plastic strains from 0% to 55%. The Vickers hardness of the specimen corresponded to the plastic strain. The residual macrostress was measured by Mn-Kα radiations. The residual macrostress of the annealed specimen had a small compression and changed into a tension after ten- sile plastic deformation. The specimen with 1% plastic strain showed the maximum tensile residual stress. To examine the dependency of the residual stress on the lattice plane, the residual microstress for each lattice plane was measured by hard synchrotron X-rays. The residual microstress was related with Young’s modulus which was calculated by Kro¨ ner model. A new method, 2θ-cos2 χ method, was proposed to solve the problem of coarse grains and it was excellent in comparison with the sin2 ψ method.
Structural and Optical Analysis of RE3+: LiNbO3 Ceramic Powders
Authors: Sreenivasulu A. , Buddhudu S.
Published: June 2010

Ferroelectric materials of LiNb0.95RE0.05O3 (RE3+=Eu3+, Sm3+, Dy3+ & Pr3+) have been prepared by a conventional solid state method. From the measurement of excitation and emission spectra of the prominent emission bands, emission performances of these optical materials have been investigated. In addition, structural analysis of these materials has also been carried out based on the data obtained from X-ray diffraction (XRD), Fourier Transform Infra-red (FTIR) spectroscopy, Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Analysis (EDAX). Lifetime measurements have also been carried out for the prominent emission transitions of these ceramic powders.
Titanium Dioxide Photocatalysts: Performance Related Properties
Authors: Bak Tadeusz , Nowotny Janusz , Nguyen Quang Vinh
Published: June 2010

The present work considers the performance-related properties of TiO2-based photosensitive semiconductors as photocatalysts for water purification and photoelectrodes for water splitting. These properties, including electronic structure, charge transport, surface properties, and near-tosurface properties, have an effect on light absorption and its conversion into chemical energy, and are closely related to defect disorder. Therefore, defect chemistry may be used as a framework for their modification in order to achieve enhanced performance. The present work considers the relationships between these specific performance-related properties and defect disorder.
Investigations of Photo-Excited TiO2 Based on Time Resolved Microwave Conductivity and Oxygen Isotopic Exchange
Authors: Pichat Pierre , Enriquez Rosario , Mietton Estelle
Published: June 2010

Charge recombination is the main drawback of heterogeneous photocatalysis; it considerably limits the applications. Consequently, it is of paramount importance to study this process. Time resolved microwave conductivity (TRMC) is an appropriate technique for that purpose since it allows measurements without electrical contacts. Here are presented and discussed results obtained by TRMC for TiO2 powders. They indicate the importance of the TiO2 particle diameter in determining the conductivity. The attraction of TiO2 photoproduced electrons to deposited Pt particles was also shown by TRMC, as well as the very rapid charge recombination in TiO2 homogeneously doped with 0.85 ion % of Cr3+ cations. TRMC measurements for TiO2 affixed on thin fiberglass tissues using SiO2 as a binder demonstrated that TRMC is also adapted to composite materials; the type of SiO2 had only a secondary influence on the conductivity. Additionally, the effects of alcohols were investigated by TRMC to illustrate the occurrence of interfacial charge transfer. On the other hand, oxygen isotope exchange (OIE) of gaseous 18O2 occurs over photo-excited Ti16O2. It is believed to be facilitated by surface irregularities which can thus be probed. OIE measurements in the presence of compounds whose photocatalytic oxidation primary step requires the incorporation of an O atom suggested that labile O atoms of TiO2 do not play the dominant role. Contrasted effects on OIE and photocatalytic removal of methanol in air showed (i) the influence of thermal treatment on TiO2 surface re-structuring (ii) the preferential adsorption and subsequent UV-induced reduction of Se salts at more labile surface O atoms.
Structure of the Near Stoichiometric Thermally Treated Co2NiGa Heusler Compounds
Authors: Prusik Krystian , Morawiec Henryk , Lelątko Józef , Drdzeń Andrzej , Dercz Grzegorz
Published: June 2010

Series of the near stoichiometric two phase (martensite + , parent + ) Co2NiGa alloys were studied. Different thermal treatments changing the microstructure were applied. After annealing for 20 h at 9000C large  precipitates were dispersed, they decorated mainly the grain boundaries. For the alloys quenched from the 11000C modulated structures were observed. Furthermore, during aging at the 3500C ' precipitation process occured in the matrix.
Studies of NiTi Shape Memory Alloy after Severe Plastic Deformation
Authors: Stróż Danuta , Dercz Grzegorz , Pawlicki Jacek , Palka J.
Published: June 2010

The results presented here concern the NiTi alloy subjected to plastic deformation by compression combined with reversion oscillating torsion. The compression rate was 0.05 mm/s and the torsion frequency and angle were 1Hz and ± 3o, respectively. The maximal strain obtained was c = 6.20. The structure of the deformed samples was studied with the use of X-ray phase analysis and TEM observations. It was found that the structure consists of a mixture of highly deformed B2 parent phase and B19’ martensite. The strain distribution after the applied plastic deformation was not uniform, the highest strain region was in the middle of the cylinder sample. In these regions small amount of the Ni2Ti phase was indentified. The TEM studies revealed some amorphous areas in the most strained region of the samples.
Structure Refinement of the Multi-Phase Mg-Al-Sr Alloy
Authors: Rzychoń Tomasz , Kiełbus Andrzej , Dercz Grzegorz
Published: June 2010

The AJ63 magnesium alloy contains 6 wt.% aluminum and 3 wt.% strontium. The typical microstructure of this alloy contains grains of solid solution of magnesium, lamellar precipitation of Al4Sr phase and massive-type phase. This phase was tentatively named Al3Mg13Sr and its crystal structure is not yet clearly determined. Paper presents the results of Rietveld fitting for AJ63 magnesium alloy and model of the crystal structure for Al3Mg13Sr compound.
The Structure and Mechanical Properties of Al-7%SiMg Alloy Treated with a Homogeneous Modifier
Authors: Lipiński Tomasz
Published: June 2010

Results of studies on the modification of Al-7%SiMg alloy with a homogeneous modifier obtained by fast cooling of homogeneous modifiers at V=200 K/s are presented in the paper. Homogeneous modifiers are additions designed for modification of the alloys from which they were obtained at 0, 7, 12 and 20% Si. The components were put into a crucible containing liquid Al-Si alloy and kept there for one minute. The effects of cooling rate and w/w concentration of the modifier in the melt on structure and tensile strength, percentage elongation, Brinell hardness, abrasive wear are illustrated graphically. The analysis of the process of hypo-eutectic Al-Si alloy modification with a homogeneous modifier obtained from treated alloy by fast cooling shows that this modifying addition affected structural,physical and mechanical properties of Al-7%SiMg alloy.
XRD Multi-Temperatures Study of N,N'-bis(2-Hydroxyethyl)Benzene-1,4-Dicarboxamide
Authors: Bednarek Gabriela , Nowak Maria , Kusz Joachim , Ossowski Jerzy
Published: June 2010

N,N’ – bis – (2– hydroxy – ethylene) – terephthalamide (BHETA) has been obtained by aminolysis of polyethylene terephthalate (PET) using excess of monoethanoloamine and it has been physicochemically characterized [1]. In this paper there are shown the results of the multi-temperature X-ray measurement which were performed to provide information about the stability of the structure. Detailed temperature analysis of the crystal structure allows us to determine properties of the compound which is very important product of recycling PET wastes in order to use it for further chemical reactions. The structure of the title compound was also modelled by density functional theory (DFT) calculations.
X Ray Topography Study of Deformed Crystal-Quasicrystal Composites of Al Cu Fe Alloy
Authors: Bogdanowicz Włodzimierz , Krawczyk Jacek
Published: June 2010

Crystal-quasicrystal columnar composites (CQ composites) of Al Cu Fe alloy subject to tensile strain at room temperature were studied by the reflective X ray topography. In those composites singlecrystalline β phase occurred as the matrix and rods consisting of quasicrystalline ψ phase and crystalline λ phase as the reinforcement. X-ray topograms of plate like composite specimens were obtained using reflexes of singlecrystalline matrix. It has been found that at strains ε up to 0.33% in a linear range of stress strain σ(ε) relationship the topograms remain unchanged. Instead, at ε higher than 0.33% significant contract changes have been observed in some areas of topograms. It has been determined that at ε higher than 0.33% the components of misorientation angle of those areas increase with increasing strain. Methods of powder phase analysis, metallographic examinations by means of optical microscopy methods and X-ray diffraction topography methods were used.
Surface Microstructure of NiCrBSi Coatings Deposited by Flame Spray and Evaluation of the Oxidation Resistance
Authors: Chaliampalias D. , Vourlias G. , Skolianos Stefanos , Polychroniadis Efstathios K. , Stergioudis F.
Published: June 2010

In the herein work coatings containing NiCrBSi alloy were deposited on low carbon steel by flame spray technique. The microstructure and morphology of the coatings were examined by electron microscopy and X-ray diffraction analysis. The as sprayed coatings are extremely rough with characteristic lamellic formations and porosity while a nanometer oxide film was formed on the top of the coating. High temperature oxidation tests revealed the high resistance of these coatings when exposed in such environment. This is mostly attributed to the existence of the temperature resistant oxide scale on the surface of the coupons.
The Characteristic of the Multilayer Thin Films by X-Ray Reflectometry Method
Authors: Bierska-Piech Bożena , Chocyk Dariusz , Prószyński Adam , Łągiewka Eugeniusz
Published: June 2010

The X-ray reflectometry (XR), as a non-destructive method, is a powerful tool
in obtaining information about parameters of thin films such as thickness, average density and interface roughness.
In this paper Cu/Au, Au/Cu and Cu/Ag multilayer thin films (where the total thickness is less then 1000Å) are presented. The multilayer films are obtained by thermal evaporation in a UHV system, on the silicon substrate. The experimental XR curves contained critical angle and classical Kiessig’s fringes. For these materials the density (), the thickness () and interface roughness () information for every layer separately were calculated.
The experimental reflectometry curves were analyzed using the WinGixa programme X’Pert software. The values of layer density show that they are reached in neighbor density and it is connected with the creation of the Cu-Au or Ag-Cu interlayer reached into Cu, Au or Ag, respectively. The analysis of roughness show that there are comparable to roughness of substrate only for 2-3 first layers. Further the roughness of Cu, Au, Ag layers are increasing. The comparison of results show that increasing of Ag an Au roughness is bigger than Cu.
Down's Syndrome with Alzheimer's Disease-Like Pathology: What Can It Teach Us about the Amyloid Cascade Hypothesis?
Authors: Bakkar Rania M. , Luo Guangju , Webb Thomas A. , Crutcher Keith A. , de Courten-Myers Gabrielle M.
Published: June 2010

Down's syndrome (DS, trisomy 21) represents a complex genetic abnormality that leads to pathology in later life that is similar to Alzheimer's disease (AD). We compared two cases of DS with APOE 3/3 genotypes, a similar age at death, and comparable amyloid-beta 42 peptide (A42) burdens in the brain but that differed markedly in the severity of AD-like pathology. One exhibited extensive neurofibrillary pathology whereas the other showed minimal features of this type. Comparable loads of A42 could relate to the cases' similar life-time accumulation of A due to trisomy 21-enhanced metabolism of amyloid precursor protein (APP). The cases' significant difference in AD-like pathology, however, suggests that parenchymal deposition of A42, even when extensive, may not inevitably trigger AD-like tau pathology (though it may be necessary). Thus, these observations of a natural experiment may contribute to understanding the nuances of the amyloid cascade hypothesis of AD pathogenesis.
Research Needed to Support Clinical Use of Biomarkers as Prognostic Indicators for Patients with Heart Failure
Authors: Rector Thomas S. , Anand Inder S.
Published: June 2010

Despite extensive research and numerous publications biomarkers have yet to fulfill their promise as prognostic indicators that can be widely used in the care of patients with heart failure. Specific clinical applications need to be identified for informative analyses of data that emphasize the most directly applicable measures of predictive performance.
Addison's Disease Revisited in Poland: Year 2008 versus Year 1990
Authors: Kasperlik-Zaluska Anna A. , Czarnocka Barbara , Jeske Wojciech , Papierska Lucyna
Published: June 2010

This study aimed at comparing two groups of patients with Addison's disease: A, including 180 patients described in 1991 and B, consisting of 138 patients registered since 1991. The incidence of coexisting autoimmune disorders was evaluated and etiological factors were analyzed. Immunological and imaging studies (computed tomography in group B) were performed. Adrenal autoantibodies were examined by an indirect immunofluorescence technique in group A, and by the assay measuring autoantibodies against steroid 21-hydroxylase in group B. Adrenal autoantibodies were revealed in 37% of patients examined by the immunofluorescence method and in 63% investigated by the modern technique. Tuberculosis was found in 52 patients in the group A and in two patients in the group B; metastatic infiltrations of the adrenals in CT were detected in 16 patients. Probable autoimmune Addison's disease was diagnosed in 125/180 patients (69%) in the group A and in 116/138 patients (84%) in the group B.
Allele Frequencies of 10 Autosomal STR Loci from Chakma and Tripura Tribal Populations in Bangladesh
Authors: Ferdous Ahmad , Ali Mohammad Eunus , Alam Shafiul , Hasan Mahamud , Hossain Tania , Akhteruzzaman Sharif
Published: June 2010

Allele frequencies of ten autosomal STR loci, D3S1358, vWA, D16S539, D2S1338, D8S1179, D21S11, D18S51, D19S433, TH01, and FGA were investigated in Chakma and Tripura tribal populations of Bangladesh. In both the populations, all loci were in Hardy-Weinberg equilibrium except for FGA locus in Chakma and D21S11 in Tripura. All the loci were highly polymorphic in Chakma population with an observed heterozygosity (Ho) of >0.7 and moderately polymorphic in Tripura population (Ho>0.6). However, both the population showed least polymorphism at TH01 locus (Ho<0.6). A comparison between Chakma and Tripura population data revealed statistically significant differences in allele frequency distribution for most of the loci. A similar comparison with the mainstream Bengali population using previously published data from this lab also showed significant difference in allele frequency with these two tribal populations.
Cervical intramedullary schwannoma: a case report and review of the literature
Authors: Nicácio Jardel Mendonça , Rodrigues José Carlos , Galles Marcos Henrique Lima , Faquini Igor Vilela , de Brito Pereira Clemente Augusto , Ganau Mario
Published: June 2010

Intramedullary schwannomas unrelated with neurofibromatosis are uncommon tumors, but if correctly diagnosed and properly treated they may have a good prognosis.

They have a wide range of clinical presentations, commonly presenting as a slowly progressive motor or sensory syndrome. We present a case report of a patient without neurofibromatosis with a surgically treated cervical intramedullary schwannoma.
 Challenging the ‘Four Corner Press’ as framework for invitational leadership in South African schools
Authors: Niemann Rita , Swanepoel Zendré , Marais Nalize
Published: June 2010

Orientation: Invitational leadership (IL) is consistent with current leadership trends and, because South African schools are in need of sound leadership, it is necessary to have a framework that can guide principals to act in accordance with the expectations of their educators.Research purpose: This study challenges the internationally accepted ‘Four Corner Press’ of Purkey and Novak (1984) as a framework for IL in the South African school context.Motivation for the study: IL appears to be a comprehensive model for successful school leadership. This necessitated an investigation to determine whether the ‘Four Corner Press’ reflects the expectations of teachers and, if so, whether it could serve as a valuable leadership tool.Research design, approach and method: A questionnaire containing 31 Likert-scale items, underpinned by the principles of IL, was disseminated to 600 educators conveniently drawn from the population of 88 828 teachers in Free State and Eastern Cape schools.Main findings: The data obtained from the survey enabled the researchers to perform a factor analysis, which revealed that South African educators’ expectations of leadership aligned with the ‘Four Corner Press’.Managerial implications: The ‘Four Corner Press’ can be used as a plausible framework for IL in South African schools, which has implications for the development and training of principals.Contribution/value-add: The ‘Four Corner Press’ can be regarded as a reliable prototype of IL expectations within the South African context, which contributes to extending the body of knowledge of education leadership in South Africa.
Observation operator for the assimilation of aerosol type resolving satellite measurements into a chemical transport model
Authors: Schroedter-Homscheidt M. , Elbern H. , Holzer-Popp T.
Published: June 2010

Abstract. Modelling of aerosol particles with chemical transport models is still based mainly on static emission databases while episodic emissions can not be treated sufficiently. To overcome this situation, a coupling of chemical mass concentration modelling with satellite-based measurements relying on physical and optical principles has been developed. This study deals with the observation operator for a component-wise assimilation of satellite measurements. It treats aerosol particles classified into water soluble, water insoluble, soot, sea salt and mineral dust containing aerosol particles in the atmospheric boundary layer as separately assimilated aerosol components. It builds on a mapping of aerosol classes used both in observation and model space taking their optical and chemical properties into account. Refractive indices for primary organic carbon particles, anthropogenic particles, and secondary organic species have been defined based on a literature review. Together with a treatment of different size distributions in observations and model state, this allows transforming the background from mass concentrations into aerosol optical depths. A two-dimensional, variational assimilation is applied for component-wise aerosol optical depths. Error covariance matrices are defined based on a validation against AERONET sun photometer measurements. Analysis fields are assessed threefold: (1) through validation against AERONET especially in Saharan dust outbreak situations, (2) through comparison with the British Black Smoke and Sulphur Dioxide Network for soot-containing particles, and (3) through comparison with measurements of the water soluble components SO4, NH4, and NO3 conducted by the EMEP (European Monitoring and Evaluation Programme) network. Separately, for the water soluble, the soot and the mineral dust aerosol components a bias reduction and subsequent a root mean square error reduction is observed in the analysis for a test period from July to November 2003. Additionally, examples of an improved analysis during wildfire and dust outbreak situations are shown.
Spatial features of rain frequency change induced by pollution and associated aerosols
Authors: Lin Yanfen , Min Qilong , Zhuang Guoshun , Wang Zuwu , Gong Wei , Li Rui
Published: June 2010

Abstract. A spatial-temporal analysis has been conducted using satellite observed distributions of rain frequency, NO2 concentration and aerosol, with focus on the spring season. As revealed by measurements from 1998–2009 over Shanghai, China, the suppression of rain is mainly attributed to the reduction of rain occurrence rather than changes in rain intensity. The overall features emerge from the region-by-region analyses that there is an inverse relationship between the rain frequency and the pollution and associated aerosols at continental scale in spring. The enhancement of pollution-produced CCN in addition to mineral dust from long-term transport suppresses the rain frequency, as favored by topography, wind, and other meteorological conditions.
The statistical properties of spread F observed at Hainan station during the declining period of the 23rd solar cycle
Authors: Wang G. J. , Shi J. K. , Wang X. , Shang S. P. , Zherebtsov G. , Pirog O. M.
Published: June 2010

Abstract. The temporal variations of the low latitude nighttime spread F (SF) observed by DPS-4 digisonde at low latitude Hainan station (geog. 19.5° N, 109.1° E, dip lat. 9.5° N) during the declining solar cycle 23 from March 2002 to February 2008 are studied. The spread F measured by the digisonde were classified into four types, i.e., frequency SF (FSF), range SF (RSF), mixed SF (MSF), and strong range SF (SSF). The statistical results show that MSF and SSF are the outstanding irregularities in Hainan, MSF mainly occurs during summer and low solar activity years, whereas SSF mainly occurs during equinoxes and high solar activity years. The SSF has a diurnal peak before midnight and usually appears during 20:00–02:00 LT, whereas MSF peaks nearly or after midnight and occurs during 22:00–06:00 LT. The time of maximum occurrence of SSF is later in summer than in equinoxes and this time delay can be caused by the later reversal time of the E×B drift in summer. The SunSpot Number (SSN) dependence of each type SF is different during different season. The FSF is independent of SSN during each season; RSF with SSN is positive relation during equinoxes and summer and is no relationship during the winter; MSF is significant dependence on SSN during the summer and winter, and does not relate to SSN during the equinoxes; SSF is clearly increasing with SSN during equinoxes and summer, while it is independent of SSN during the winter. The occurrence numbers of each type SF and total SF have the same trend, i.e., increasing as Kp increases from 0 to 1, and then decreasing as increasing Kp. The correlation with Kp is negative for RSF, MSF, SSF and total SF, but is vague for the FSF.
Density/area power-law models for separating multi-scale anomalies of ore and toxic elements in stream sediments in Gejiu mineral district, Yunnan Province, China
Authors: Cheng Q. , Xia Q. , Li W. , Zhang S. , Chen Z. , Zuo R. , Wang W.
Published: June 2010

Abstract. This contribution introduces a fractal filtering technique newly developed on the basis of a spectral energy density vs. area power-law model in the context of multifractal theory. It can be used to map anisotropic singularities of geochemical landscapes created from geochemical concentration values in various surface media such as soils, stream sediments, tills and water. A geochemical landscape can be converted into a Fourier domain in which the spectral energy density is plotted against the area (in wave number units), and the relationship between the spectrum energy density (S) and the area (A) enclosed by the above-threshold spectrum energy density can be fitted by power-law models. Mixed geochemical landscape patterns can be fitted with different S-A power-law models in the frequency domain. Fractal filters can be defined according to these different S-A models and used to decompose the geochemical patterns into components with different self-similarities. The fractal filtering method was applied to a geochemical dataset from 7349 stream sediment samples collected from Gejiu mineral district, which is famous for its word-class tin and copper production. Anomalies in three different scales were decomposed from total values of the trace elements As, Sn, Cu, Zn, Pb, and Cd. These anomalies generally correspond to various geological features and geological processes such as sedimentary rocks, intrusions, fault intersections and mineralization.
A shift in the spatial pattern of Iberian droughts during the 17th century
Authors: Domínguez-Castro F. , García-Herrera R. , Ribera P. , Barriendos M.
Published: June 2010

Abstract. In this paper, series of drought occurrence and drought extension in the Iberian Peninsula are constructed for the 1600–1750 period from seven rogation series. These rogation ceremony records come from Bilbao, Catalonia, Zamora, Zaragoza, Toledo, Murcia and Seville. They are distributed across the Peninsula and include the areas with the most characteristic Iberian climate types, influenced by the Atlantic and the Mediterranean conditions, described from modern data. A seasonal division of the series shows that spring is a critical season for rogation series in most of Iberia, being Bilbao the only site were the highest number of rogations is detected for a different season. The annual analysis of the series shows a dramatic difference between the period 1600–1652, when droughts are characterized by its local character; and the period 1653–1749, when they affect to broader regions or even to the whole Peninsula. The analysis of spring series confirms the existence of the two periods detected in the annual analysis. Finally, secondary documentary sources are used to further characterise the two most extended droughts in the period, 1664 and 1680, and to verify the extension of the areas affected by droughts recorded through rogation series.
The interaction of northern wind flow with the complex topography of Crete Island – Part 2: Numerical study
Authors: Koletsis I. , Lagouvardos K. , Kotroni V. , Bartzokas A.
Published: June 2010

Abstract. During the summer months, when northerly winds are blowing over the Aegean Sea the island of Crete modifies significantly the regional airflow as well as the pressure and temperature fields due to its complex topography. One of the major topographical elements of Crete Island is the major gap which is located between the two highest mountains Lefka Ori and Idi. On 24–25 August 2007 strong northerly winds, with gusts up to 25 m s−1, occurred at the exit of the major gap. In order to investigate the dynamics as well as the role of this elevated and sloping gap on the airflow modification, the event was simulated down to 1 km horizontal resolution using the non-hydrostatic model MM5. The model simulations show that the localized intensification of the flow downstream of the major gap is related to the channeling of the flow through the gap. The strongest winds are observed at the gap exit region, implying that the main cause of the strong winds is the pressure different between the gap entrance and exit, when the relatively cooler maritime air approached the island and dammed up the high mountains. Finally, sensitivity experiments with modified topography further supported the important role of the topography of the elevated gap, which reveals that the strong winds have aspects of both gap and downslope contributions over the gap exit.
Automated gas bubble imaging at sea floor – a new method of in situ gas flux quantification
Authors: Thomanek K. , Zielinski O. , Sahling H. , Bohrmann G.
Published: June 2010

Abstract. Photo-optical systems are common in marine sciences and have been extensively used in coastal and deep-sea research. However, due to technical limitations in the past photo images had to be processed manually or semi-automatically. Recent advances in technology have rapidly improved image recording, storage and processing capabilities which are used in a new concept of automated in situ gas quantification by photo-optical detection. The design for an in situ high-speed image acquisition and automated data processing system is reported ("Bubblemeter"). New strategies have been followed with regards to back-light illumination, bubble extraction, automated image processing and data management. This paper presents the design of the novel method, its validation procedures and calibration experiments. The system will be positioned and recovered from the sea floor using a remotely operated vehicle (ROV). It is able to measure bubble flux rates up to 10 L/min with a maximum error of 33% for worst case conditions. The Bubblemeter has been successfully deployed at a water depth of 1023 m at the Makran accretionary prism offshore Pakistan during a research expedition with R/V Meteor in November 2007.
Holoprosencephaly and genitourinary anomalies in fetal methotrexate syndrome
Authors: Corona‐Rivera J. Román , Rea‐Rosas Alejandro , Santana‐Ramírez Adrián , Acosta‐León Jorge , Hernández‐Rocha Juan , Miguel‐Jiménez Karla
Published: June 2010

Prenatal exposure to methotrexate (MTX) in the first trimester may lead to fetal death, and surviving children have increased risks for cranial dysostosis, dysmorphic facies, skeletal malformations, limb defects, growth retardation, and, in some cases, developmental delay, a pattern of defects recognized as fetal MTX syndrome (FMS). We report on a male infant who, in addition to severe FMS, showed previously undescribed central nervous system (CNS) and genitourinary anomalies that contributed to the further delineation. The propositus was born to a G2, 20‐year‐old mother with an irregular menstrual history. The unplanned pregnancy was complicated by oral MTX treatment (5 mg/day) for suspected systemic lupus erythematosus for 14 days at the 5th week post‐conception, as dated by the first trimester sonogram. In addition to the typical features of the FMS, our propositus exhibited congenital penile curvature, vesicoureteral reflux, hydronephrosis, and severe CNS anomalies including semilobar holoprosencephaly (HPE). A single previous report of lobar‐type HPE in an infant with FMS led us to confirm that the HPE observed in the propositus is a feature attributable to MTX teratogenicity, although the exact mechanisms of the HPE production need to be further elucidated. Also, this case serves to highlight the presence of genitourinary anomalies in patients with FMS, a fact that requires intentional searches in future patients in order to confirm this as being characteristic of the entity. © 2010 Wiley‐Liss, Inc.
Pattern of maternal circulating CRH in laboratory‐housed squirrel and owl monkeys
Authors: Power M.L. , Williams L.E. , Gibson S.V. , Schulkin J. , Helfers J. , Zorrilla E.P.
Published: June 2010

The anthropoid primate placenta appears to be unique in producing corticotropin‐releasing hormone (CRH). Placental CRH is involved in an endocrine circuit key to the production of estrogens during pregnancy. CRH induces cortisol production by the maternal and fetal adrenal glands, leading to further placental CRH production. CRH also stimulates the fetal adrenal glands to produce dehydroepiandrostendione sulfate (DHEAS), which the placenta converts into estrogens. There are at least two patterns of maternal circulating CRH across gestation among anthropoids. Monkeys examined to date (Papio and Callithrix) have an early‐to‐mid gestational peak of circulating CRH, followed by a steady decline to a plateau level, with a possible rise near parturition. In contrast, humans and great apes have an exponential rise in circulating CRH peaking at parturition. To further document and compare patterns of maternal circulating CRH in anthropoid primates, we collected monthly blood samples from 14 squirrel monkeys (Saimiri boliviensis) and ten owl monkeys (Aotus nancymaae) during pregnancy. CRH immunoreactivity was measured from extracted plasma by using solid‐phase radioimmunoassay. Both squirrel and owl monkeys displayed a mid‐gestational peak in circulating CRH: days 45–65 of the 152‐day gestation for squirrel monkeys (mean±SEM CRH=2,694±276 pg/ml) and days 60–80 of the 133‐day gestation for owl monkeys (9,871±974 pg/ml). In squirrel monkeys, circulating CRH declined to 36% of mean peak value by 2 weeks before parturition and then appeared to increase; the best model for circulating CRH over gestation in squirrel monkeys was a cubic function, similar to previous results for baboons and marmosets. In owl monkeys, circulating CRH appeared to reach plateau with no subsequent significant decline approaching parturition, although a cubic function was the best fit. This study provides additional evidence for a mid‐gestational peak of maternal circulating CRH in ancestral anthropoids that has been lost in the hominoid lineage. Am. J. Primatol. 72:1004–1012, 2010. © 2010 Wiley‐Liss, Inc.