bluuebunny/crossref_metadata_2025 huggingface dataset:
Empirical forecasts of tropical Atlantic sea surface temperature anomalies
Authors: De Elvira A. Ruiz , Beviá M. J. Ortiz , Narvaez W. Cabos
Published: September 2010

The interannual variability of the tropical Atlantic is characterized by warmings and coolings similar to the Pacific ones (El Niño), and by an interhemispheric signal of decadal variability. The magnitudes of the Gulf of Guinea warmings are less and, therefore, they do not significantly influence the earth's climate, as the El Niño/Southern Oscillation (ENSO) does. In the past, they have been studied because of their connections with the recurrent droughts in the Sahel region. Recently, a number of modelling studies have tried to establish their dependence on ENSO. The real existence of an interhemispheric decadal signal, and its predictability, is also a widely discussed topic. Forecast studies have recently appeared for both the north tropical Atlantic and the Gulf of Guinea regions, and are now operationally available from the National Oceanic and Atmospheric Administration.

In the present work we try first to understand the tropical Atlantic variability in terms of forcings external to the basin. These are identified from 48 years of monthly anomalies of sea surface temperature (SST) data obtained by combining the Comprehensive Ocean and Atmosphere Dataset (COADS) and the Integrated Global Ocean Services System (IGOSS) dataset, and then using the Bayesian theory of estimation. Besides the ENSO‐related scales, our analysis retains a decadal time scale in the data variability.

Next, a model is built to forecast the most important features of the equatorial Atlantic interannual variability. These features are monitored through two indices, the Gulf of Guinea and the north tropical Atlantic indices (‘the predictands’). Predictor fields are identified from our preliminary analysis, as those time series significantly correlated with the predictands. These correspond to grid points in the tropical Pacific (mainly the Niño3 region, (5°S–5°N, 150°W–90°W)) and tropical Indian oceans. Forecasts were issued for 28 years, at three‐monthly intervals. For the north tropical Atlantic index, we have a good forecast skill at leads greater than four months with predictors obtained from east equatorial Pacific time series. For the Gulf of Guinea index, a good forecast skill can be obtained only when we include time series of the equatorial Indian ocean, as well as the east equatorial Pacific, among the predictors. Any of the forecasts presented here show useful forecast skill that, at least, beats persistence at leads greater than four months
Introducing haptic capabilities to a bone‐mounted robot for intra‐operative surface scanning
Authors: Shapiro Yoel , Wolf Alon
Published: September 2010

Background

Bone‐mounted robots for orthopaedic surgery are small, cost‐effective and could reduce invasiveness. Preoperative planning requires imaging (e.g. X‐ray, CT, MRI) and a registration procedure, which introduces error. Accuracy might be improved by building an intraoperative anatomical model in the robot's own coordinate system, utilizing the rigid bone–robot connection.

Methods

Haptic capabilities were added to MBARS and user tests were conducted to help design the haptic control loop. The accuracy of a 3D physical scan was tested on a femur model.

Results

Indication for force scaling and mode switching was found. Average distance error of collected points from the surface scanned by the robot was 0.3 mm.

Conclusions

It is suggested that haptic control of bone‐mounted robots should be non‐linear and not necessarily transparent. Haptic surface acquisition can be used to generate an accurate intraoperative model of a joint surface. Copyright © 2010 John Wiley & Sons, Ltd.
Shadow of the contract: how contract structure shapes interfirm dispute resolution
Authors: Lumineau Fabrice , Malhotra Deepak
Published: September 2010

This paper investigates how contract structure influences interfirm dispute resolution processes and outcomes by examining a unique dataset consisting of over 150,000 pages of documents relating to 102 business disputes. We find that the level of contract detail affects the type of dispute resolution approach that is adopted when conflict arises, and that different approaches are associated with different costs for resolving the dispute. We also find that the effect of contract choice on dispute resolution approach is moderated by the degree of coordination required in the relationship, and that the effect of dispute approach on costs is moderated by the degree of power asymmetry between the parties. Thus, even after controlling for various attributes of the exchange relationship and the dispute, the choice of contracting structure has important strategic implications. Copyright © 2010 John Wiley & Sons, Ltd.
Porous Graphene as an Atmospheric Nanofilter
Authors: Blankenburg Stephan , Bieri Marco , Fasel Roman , Müllen Klaus , Pignedoli Carlo A. , Passerone Daniele
Published: September 2010

The fabrication of nanoscale membranes exhibiting high selectivity is an emerging field of research. The possibility to use bottom‐up approaches to fabricate a filter with porous graphene and analyze its functionality with first principle calculations is investigated. Here, the porous network is produced by self‐assembly of the hexaiodo‐substituted macrocycle cyclohexa‐m‐phenylene (CHP). The resulting porous network exhibits an extremely high selectivity in favor of H2 and He among other atmospheric gases, such as Ne, O2, N2, CO, CO2, NH3, and Ar. The presented membrane is superior to traditional filters using polymers or silica and could have great potential for further technological applications such as gas sensors or fuel cells.
Preparation and swelling properties of a pH‐sensitive superabsorbent hydrogel based on psyllium gum
Authors: An Jian‐Ke , Wang Wen‐Bo , Wang Ai‐Qin
Published: September 2010

A series of natural polymer‐based superabsorbent hydrogels were prepared by free radical graft copolymerization of partially neutralized acrylic acid (AA) onto psyllium gum (PSY) in aqueous solution, using ammonium persulfate (APS) as the initiator, and N,N′‐methylenebisacrylamide (MBA) as the crosslinker. Fourier transform infrared spectroscopy (FTIR) confirmed that AA monomers have been grafted onto PSY macromolecular chains. The swelling properties of the hydrogels in various saline and pH solutions were investigated, and the swelling kinetics and reswelling ability of the hydrogels were also evaluated systematically. The hydrogels showed excellent responsive properties and reversible On‐Off switching characteristics in various pH buffer solutions, which render the hydrogels available as a candidate for drug delivery system.
Diagnosis and morbidity of placenta accreta
Authors: Esakoff T. F. , Sparks T. N. , Kaimal A. J. , Kim L. H. , Feldstein V. A. , Goldstein R. B. , Cheng Y. W. , Caughey A. B.
Published: September 2010

Objective

To examine the diagnostic precision of ultrasound examination for placenta accreta in women with placenta previa and to compare the morbidity associated with accreta to that of previa alone.

Methods

This was a retrospective cohort study of all women with previa with/without accreta examined at the University of California, San Francisco (UCSF) between 2002 and 2008. The sensitivity, specificity, negative predictive value (NPV) and positive predictive value (PPV) of ultrasound examination for the diagnosis of accreta were calculated and compared with results from similar studies in the literature. Univariable analysis was used to compare clinical outcomes.

Results

The PPV of an ultrasound diagnosis of accreta was 68% and NPV was 98%. Ultrasound had a sensitivity of 89.5%. Compared with previa alone, accreta had an odds ratio (OR) of 89.6 (95% CI, 19.44–412.95) for estimated blood loss > 2 L, an OR of 29.6 (95% CI, 8.20–107.00) for transfusion and an OR of 8.52 (95% CI, 2.58–28.11) for length of hospital stay > 4 days.

Conclusion

Placenta accreta is associated with greater morbidity than is placenta previa alone. Ultrasound examination is a good diagnostic test for accreta in women with placenta previa. This is consistent with most other studies in the literature. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.
Animal cognition
Authors: Vallortigara Giorgio , Chiandetti Cinzia , Rugani Rosa , Sovrano Valeria Anna , Regolin Lucia
Published: September 2010

The main topics in the study of animal cognition are reviewed with special reference to direct links to human, and in particular developmental, cognitive sciences. The material is organized with regard to the general idea that biological organisms would be endowed with a small set of separable systems of core knowledge, a prominent hypothesis in the current developmental cognitive sciences. Core knowledge systems would serve to represent inanimate physical objects and their mechanical interactions (natural physics); numbers with their relationships of ordering, addition, and subtraction (natural mathematics); places in the spatial layout with their geometric relationships (natural geometry); and animate psychological objects (agents) with their goal‐directed actions (natural psychology). Some advanced forms of animal cognition, such as episodic‐like representations and planning for the future, are also discussed. WIREs Cogn Sci 2010 1 882–893

This article is categorized under:

Psychology > Comparative Psychology
Antenatal diagnosis of pompe disease by fetal echocardiography: impact on outcome after early initiation of enzyme replacement therapy
Authors: Hamdan Mohamed A. , El‐Zoabi Bushra A. , Begam Muzibunnisa A. , Mirghani Hisham M. , Almalik Mohamed H.
Published: September 2010

Hypertrophic cardiomyopathy (HCM) affects most infants with Pompe disease (PD), and may serve as a marker for its antenatal diagnosis (ANDx) by fetal echocardiography (FE). Fetuses diagnosed with HCM between 2006 and 2009 were included in this study. HCM, defined as Z‐score of mean left ventricular wall thickness (LVWT) and/or mass (LVM) above 2, was detected in 5/1,268 fetuses (0.39%) carried by 1,137 pregnant women referred for FE. Three fetuses (0.24%) had postnatal confirmation of PD. Their gestational age and fetal weight at diagnosis was (mean ± standard deviation) 31 ± 3.6 weeks and 1.9 ± 0.2 kg, respectively. Fetal Z‐score of LVM and LVWT was 3.8 ± 0.9 and 3.1 ± 0.6, respectively. Postnatally, acid α‐glucosidase (GAA) enzyme activity was nearly absent in all patients, 2 were homozygous for the mutation 1327‐2A>G in the GAA gene, and 1 was homozygous for 340insT. Enzyme replacement therapy (ERT) was initiated 4.9 ± 7.8 days after birth (range 2 h–14 days), and continued every 2 weeks. Two infants are alive at 4 and 31 months, and one died of aspiration pneumonia at 19 months. Cardiac hypertrophy resolved after 10–12 weeks of ERT in all patients, and none required any respiratory support. One patient had normal neurodevelopmental assessment at 25 months, and one had severe global delay at 15 months before death. ANDx of PD by FE is feasible based on fetal HCM. It promotes early initiation of ERT which may improve outcome in some patients. However, larger studies and longer follow‐ups are required.
A Tale of Two Cities: John Henry Newman and the Church of the Catacombs
Authors: MEYER WENDEL W.
Published: September 2010

John Henry Newman made two formative trips to Rome, the first as an Anglican priest in the early spring of 1833 when he spent five weeks in the Eternal City accompanied by his friend and colleague Hurrell Froude. The second trip was made shortly after he converted to Roman Catholicism in 1846. On both these journeys, Newman visited the Roman catacombs, which were certainly part of the standard tour of the day but which had become in the nineteenth century sites that were enveloped in considerable ecclesiastical and theological polemical debate. Looking at Newman's reactions to these sites, at these two very important junctures of his life and career, gives a very provocative and enlightening glimpse into the inner workings of his mind and heart. On a different but equally interesting historical plane, such an investigative lens highlights the significant number of people who were part of Newman's life during this period and who were devotionally drawn to these primitive burial sites.
Anselm: Platonism, language and truth in Proslogion
Authors: Baark Sigurd
Published: September 2010

When the Proslogion is read from within the context of Anselm's De Veritate it seems that Anselm's project is firmly based on theological premises. Anselm works with a two-fold conception of truth. Truth is first of all a quality inherent in the statement itself. It is the correctness (rectitudo) of the statement. Second, truth is the correspondence with the extra-linguistic reality. This second level of truth is accidental to the statement. What provides the link between extra-linguistic reality and the statement is the Word of God, which is the level of true reference, where original statements correspond to the original will of God in the creation. When Plato asks what true knowledge is in the Theatetus, the final answer seems to be that what is needed is a statement which carries its own truth as a certainty of Being and Unity within itself. However, no such statement is presented in the dialogue. The name of God in the Proslogion is such a statement which carries its own truth as a certainty of Being and Unity within itself, in that on the first level of truth (rectituto) it is impossible to deny. As the statement concerns the Being of God and cannot be denied it necessarily overflows into the second level of truth which is correspondence with extra-linguistic reality. Therefore, this article argues that Anselm develops a statement which fulfils the criterion of true knowledge presented in the Theatetus. He manages to do this from the position of faith, which includes a strict theological rationality.
The influence of John Chrysostom's hermeneutics on John Calvin's exegetical approach to Paul's Epistle to the Romans
Authors: Awad Najeeb George
Published: September 2010

In this article, I look at the possible impact of John Chrysostom's exegetical approach upon John Calvin's biblical interpretation. I detect the traces of Chrysostom's hermeneutical approach to Paul's Letter to the Romans in John Calvin's reading of the same epistle. Why Paul's literature? Because both Chrysostom and Calvin are very fond of Paul and his thinking and consider him the major voice in the Bible. Why the Epistle to the Romans specifically? Because they both believe that this epistle is valuable for the church at all times. According to them, it is the first door to the understanding of the Good News of God's salvation as proclaimed in the Bible. I make this comparison on the basis of the following foundational thesis. If the first Protestant reformers were reliant on the church's exegetical tradition, and if they believed in the affinity of their biblical reading to a long tradition of reading conducted before them, the impact of the church fathers' exegetical methodology on the reformers' biblical interpretation should be part and parcel of any scholarship we do on the Reformation's hermeneutics.
The marking of new information in children's narratives: a comparison of English, French, German and Mandarin Chinese*
Authors: Hickmann Maya , Hendriks Henriëtte , Roland Françoise , Liang James
Published: September 2010

This study examines children's uses of nominal determiners (‘local markings’) and utterance structure (‘global markings’) to introduce new referents. Two narratives were elicited from preschoolers, seven-year-olds, ten-year-olds, and adults in English (N= 80), French (N= 40), German (N= 40), and Chinese (N= 40). Given typological differences (e.g. richness of morphology), these languages rely differentially on local vs. global devices to mark newness: postverbal position is obligatory in Chinese (determiners optional), indefinite determiners in the other languages (position optional). Three findings recur across languages: obligatory newness markings emerge late (seven-year-olds); local markings emerge first, including Chinese optional ones; local and global markings are strongly related. Crosslinguistic differences also occur: English-speaking preschoolers use local markings least frequently; until adult age global markings are rare in English, not contrastive in German and not as frequent in Chinese as in French, despite obligatoriness. It is concluded that three factors determine acquisition: (1) universal discourse factors governing information flow; (2) cognitive factors resulting from the greater functional complexity of global markings; (3) language-specific factors related to how different systems map both grammatical and discourse functions onto forms.
Space profiling for parallel functional programs
Authors: SPOONHOWER DANIEL , BLELLOCH GUY E. , HARPER ROBERT , GIBBONS PHILLIP B.
Published: September 2010

We present a semantic space profiler for parallel functional programs. Building on previous work in sequential profiling, our tools help programmers to relate runtime resource use back to program source code. Unlike many profiling tools, our profiler is based on a cost semantics. This provides a means to reason about performance without requiring a detailed understanding of the compiler or runtime system. It also provides a specification for language implementers. This is critical in that it enables us to separate cleanly the performance of the application from that of the language implementation. Some aspects of the implementation can have significant effects on performance. Our cost semantics enables programmers to understand the impact of different scheduling policies while hiding many of the details of their implementations. We show applications where the choice of scheduling policy has asymptotic effects on space use. We explain these use patterns through a demonstration of our tools. We also validate our methodology by observing similar performance in our implementation of a parallel extension of Standard ML.
Changes in body composition relative to weight and maturity in large and small strains of Australian Merino rams
Authors: Butterfield R. M. , Zamora J. , James A. M. , Thompson J. M. , Williams Jean
Published: September 2010

Maturing patterns are established for 93 individual muscles, and nine anatomical groups of muscles, using half carcass dissection data from 39 rams of two strains of Merinos of different mature size (91 and 116 kg). The maturity coefficients of the individual muscles and muscle groups are tabulated. Seventy-eight of the 93 muscles, and eight of the nine anatomical muscle groups, had maturing patterns which were not significantly different for the strains of sheep. In general, the muscles of the limbs and muscles surrounding the spinal column were earlier-maturing than total muscle and the muscles in the cranial end of the trunk were late maturing. The muscles of the abdominal wall matured at the same rate as total muscle.

Differences in the distribution of muscle weight of the two strains of rams, when compared at the same total muscle weight, were reduced when compared at the same proportion' of mature total muscle weight. It was concluded, therefore, that apparent differences in the distribution of muscle weights, when breeds are compared at the same total muscle weight, may be due largely to differences in mature size.
Supporting Parents to Support Family Life: A Central Challenge for Family Minded Policy
Authors: Clarke Harriet
Published: September 2010

Disabled parents can experience difficulties when trying to access services to support their parenting role, and this is exacerbated wherever disability continues to be articulated as if it were impairment and associated with a need for ‘care’. Disabled parents and their families experiences of services demonstrate that, for a family approach to be positively developed within social policy, individuals should be kept in sharp focus by policy makers, practitioners and researchers. Failure to do so can result in the problematisation of parents who have support requirements, itself a barrier to the development of appropriate services for parents and families.
Lebensqualität von Kindern psychisch kranker Eltern
Authors: Wiegand-Grefe Silke , Jeske Jana , Bullinger Monika , Plaß Angela , Petermann Franz
Published: September 2010

Kinder psychisch kranker Eltern weisen im KINDL-R eine schlechtere Lebensqualität auf als eine Referenzstichprobe. Der Einfluss der Diagnosegruppe der elterlichen Erkrankung erweist sich als bedeutsam. Es gibt einige Zusammenhänge zu den unspezifischen elterlichen Erkrankungsvariablen: Je höher der Schweregrad der elterlichen Erkrankung, desto beeinträchtigter die familiäre Lebensqualität der Kinder. Wenn außerdem somatische Erkrankungen der Eltern vorliegen, ist die Lebensqualität stärker beeinträchtigt. Je länger die elterliche Erkrankung andauert und je länger die Kinder der Erkrankung ausgesetzt sind, desto positiver werden freundschaftliche Beziehungen der Kinder eingeschätzt. Schließlich ist die Lebensqualität der Kinder schlechter, wenn die subjektive elterliche Beeinträchtigung durch die Erkrankung höher ist und die Kinder bereits psychische Auffälligkeiten zeigen.
Magnetic reconnection with asymmetry in the outflow direction
Authors: Murphy N. A. , Sovinec C. R. , Cassak P. A.
Published: September 2010

Magnetic reconnection with asymmetry in the outflow direction occurs in the Earth's magnetotail, coronal mass ejections, flux cancellation events, astrophysical disks, spheromak merging experiments, and elsewhere in nature and the laboratory. A control volume analysis is performed for the case of steady antiparallel magnetic reconnection with asymmetric downstream pressure to derive scaling relations for the outflow velocity from each side of the current sheet and the reconnection rate. Simple relationships for outflow velocity are presented for the incompressible case and the case of symmetric downstream pressure but asymmetric downstream density. Asymmetry alone is not found to greatly affect the reconnection rate. The flow stagnation point and magnetic field null do not coincide in a steady state unless the pressure gradient is negligible at the flow stagnation point. The predictions of the model are compared with resistive MHD simulations of driven reconnection with asymmetry in the outflow direction.
Mixing layer dynamics in separated flow over an estuarine sill with variable stratification
Authors: Talke S. A. , Horner‐Devine A. R. , Chickadel C. C.
Published: September 2010

We investigate the generation of a mixing layer in the separated flow behind an estuarine sill (height H ∼ 4 m) in the Snohomish River, Washington as part of a larger investigation of coherent structures using remote and in situ sensing. During increasing ebb flows the depth d and stratification decrease and a region of sheared flow characterized by elevated production of turbulent kinetic energy develops. Profiles of velocity and acoustic backscatter exhibit coherent fluctuations of order 0.1 Hz and are used to define the boundaries of the mixing layer. Variations in the mixing layer width and its embedded coherent structures are caused by changes to both the normalized sill height H/d and to a bulk Richardson number Rih defined using the depth of flow over the sill. Entrainment ET and the mixing layer expansion angle increase as stratification and the bulk Richardson number decrease; this relationship is parameterized as ET = 0.07Rih−0.5 and is valid for approximately 0.1 < Rih < 2.8. Available comparisons with literature for inertially dominated conditions (Rih < 0.1) are consistent with our data and validate our approach, though lateral gradients may introduce an upwards bias of approximately 20%. As the ratio H/d increases over the ebb, the free surface boundary pushes the mixing layer trajectory downward, reduces its expansion angle, and produces asymmetry in the acoustic backscatter (coherent structures). Three‐dimensional divergence, as imaged by infrared video and transecting data, becomes more prominent for H/d > 0.8 due to blocking of flow by the sill.
Do global warming targets limit heatwave risk?
Authors: Clark Robin T. , Murphy James M. , Brown Simon J.
Published: September 2010

Climate change mitigation targets are often described in terms of annually averaged global mean temperature increases. However local interpretation of impacts resulting from these targets are required if the public is to have a sound appreciation of their consequences. Some of the largest impacts are likely to arise from changes in extreme events, for example heatwaves and floods. This article estimates future regional heat extreme changes consistent with specific global warming targets, using a new and presently unique ensemble of physically plausible climate simulations. We find that a subset of ensemble members giving globally averaged temperature increases of 2.0 ± 0.5°C shows a wide range of changes in regional temperature extremes. For example, changes in extreme single‐day hot events range between 2 and 6 °C for large parts of Europe, North America and Asia for this target. Plausible variations in the model representation of forest roughness length, vegetation root depth and boundary layer cloud make the largest individual contributions to the spread of changes found in different parts of the world. However, a wide range of processes contribute to the uncertainties in the regional changes, particularly through their direct or indirect influences on the simulation of soil moisture.
Arctic Oscillation responses to greenhouse warming and role of synoptic eddy feedback
Authors: Choi Da‐Hee , Kug Jong‐Seong , Kwon Won‐Tae , Jin Fei‐Fei , Baek Hee‐Jeong , Min Seung‐Ki
Published: September 2010

This study investigates possible changes in the leading mode over the Northern Hemisphere, representing the Arctic Oscillation (AO), in response to the projected increases in greenhouse gas concentrations. This is performed by comparing present‐day and future patterns simulated by a relatively high‐resolution atmospheric general circulation model. It is demonstrated that the dipole pattern associated with the AO distinctively shifts poleward in the future climate. The poleward shift is more pronounced over the Pacific region than over the Atlantic region. This change in the AO pattern is consistent with the change in the synoptic eddy feedback, estimated from the divergence of the eddy‐vorticity flux, indicating a close linkage between the AO change and the change in the synoptic eddy feedback. Further analysis of changes in eddy feedback strength suggests a possible hypothesis that the poleward shift of the jet stream and storm tracks can make synoptic eddy feedback more effective over the higher latitudes, which in turn enhances the poleward shift of the AO mode.
A genetic system to assess in vivo the functions of histones and histone modifications in higher eukaryotes
Authors: Günesdogan Ufuk , Jäckle Herbert , Herzig Alf
Published: September 2010

Despite the fundamental role of canonical histones in nucleosome structure, there is no experimental system for higher eukaryotes in which basic questions about histone function can be directly addressed. We developed a new genetic tool for Drosophila melanogaster in which the canonical histone complement can be replaced with multiple copies of experimentally modified histone transgenes. This new histone‐replacement system provides a well‐defined and direct cellular assay system for histone function with which to critically test models in chromatin biology dealing with chromatin assembly, variant histone functions and the biological significance of distinct histone modifications in a multicellular organism.
Functional domains of yeast hexokinase 2
Authors: Peláez Rafael , Herrero Pilar , Moreno Fernando
Published: September 2010

Hkx2 (hexokinase 2) from Saccharomyces cerevisiae was one of the first metabolic enzymes described as a multifunctional protein. Hxk2 has a double subcellular localization: it functions as a glycolytic enzyme in the cytoplasm and as a regulator of gene transcription of several Mig1-regulated genes in the nucleus. To get more insights into the structure–function relationships of the Hxk2 protein, we followed two different approaches. In the first, we deleted the last eight amino acids of Hxk2 and replaced Ser304 with phenylalanine to generate Hxk2wca. Analysis of this mutant demonstrated that these domains play an essential role in the catalytic activity of yeast Hxk2, but has no effect on the regulatory function of this protein. In the second, we analysed whether amino acids from Lys6 to Met15 of Hxk2 (Hxk2wrf) are essential for the regulatory role of Hxk2 and whether there is an effect on the hexose kinase activity of this protein. In the present paper, we report that the Hxk2wca mutant protein interacts with the Mig1 transcriptional repressor and the Snf1 protein kinase in the nucleus at the level of the SUC2–Mig1 repressor complex. We have demonstrated that Hxk2wca maintained full regulatory function because the glucose-repression signalling of the wild-type machinery is maintained. We also report that the Hxk2wrf mutant allele is incapable of glucose repression signalling because it does not interact with Mig1 at the level of the SUC2–Mig1 repressor complex. The two mutants, Hxk2wca and Hxk2wrf retain single functions, as a transcriptional factor or as an enzyme with hexose-phosphorylating activity, but have lost the original bifunctionality of Hxk2.
Chondroitin sulfate N-acetylgalactosaminyltransferase-1 is required for normal cartilage development
Authors: Watanabe Yumi , Takeuchi Kosei , Higa Onaga Susumu , Sato Michiko , Tsujita Mika , Abe Manabu , Natsume Rie , Li Minqi , Furuichi Tatsuya , Saeki Mika , Izumikawa Tomomi , Hasegawa Ayumi , Yokoyama Minesuke , Ikegawa Shiro , Sakimura Kenji , Amizuka Norio , Kitagawa Hiroshi , Igarashi Michihiro
Published: September 2010

CS (chondroitin sulfate) is a glycosaminoglycan species that is widely distributed in the extracellular matrix. To understand the physiological roles of enzymes involved in CS synthesis, we produced CSGalNAcT1 (CS N-acetylgalactosaminyltransferase 1)-null mice. CS production was reduced by approximately half in CSGalNAcT1-null mice, and the amount of short-chain CS was also reduced. Moreover, the cartilage of the null mice was significantly smaller than that of wild-type mice. Additionally, type-II collagen fibres in developing cartilage were abnormally aggregated and disarranged in the homozygous mutant mice. These results suggest that CSGalNAcT1 is required for normal CS production in developing cartilage.
Magnetic resonance imaging of myocardial injury and ventricular torsion after marathon running
Authors: Hanssen Henner , Keithahn Alexandra , Hertel Gernot , Drexel Verena , Stern Heiko , Schuster Tibor , Lorang Dan , Beer Ambros J. , Schmidt-Trucksäss Arno , Nickel Thomas , Weis Michael , Botnar Rene , Schwaiger Markus , Halle Martin
Published: September 2010

Recent reports provide indirect evidence of myocardial injury and ventricular dysfunction after prolonged exercise. However, existing data is conflicting and lacks direct verification of functional myocardial alterations by CMR [cardiac MR (magnetic resonance)]. The present study sought to examine structural myocardial damage and modification of LV (left ventricular) wall motion by CMR imaging directly after a marathon. Analysis of cTnT (cardiac troponin T) and NT-proBNP (N-terminal pro-brain natriuretic peptide) serum levels, echocardiography [pulsed-wave and TD (tissue Doppler)] and CMR were performed before and after amateur marathon races in 28 healthy males aged 41±5 years. CMR included LGE (late gadolinium enhancement) and myocardial tagging to assess myocardial injury and ventricular motion patterns. Echocardiography indicated alterations of diastolic filling [decrease in E/A (early transmitral diastolic filling velocity/late transmitral diastolic filling velocity) ratio and E′ (tissue Doppler early transmitral diastolic filling velocity)] postmarathon. All participants had a significant increase in NT-proBNP and/or cTnT levels. However, we found no evidence of LV LGE. MR tagging demonstrated unaltered radial shortening, circumferential and longitudinal strain. Myocardial rotation analysis, however, revealed an increase of maximal torsion by 18.3% (13.1±3.8 to 15.5±3.6 °; P=0.002) and maximal torsion velocity by 35% (6.8±1.6 to 9.2±2.5 °·s−1; P<0.001). Apical rotation velocity during diastolic filling was increased by 1.23±0.33 °·s−1 after marathon (P<0.001) in a multivariate analysis adjusted for heart rate, whereas peak untwist rate showed no relevant changes. Although marathon running leads to a transient increase of cardiac biomarkers, no detectable myocardial necrosis was observed as evidenced by LGE MRI (MR imaging). Endurance exercise induces an augmented systolic wringing motion of the myocardium and increased diastolic filling velocities. The stress of marathon running seems to be better described as a burden of myocardial overstimulation rather than cardiac injury.
Integrability of an inhomogeneous nonlinear Schrödinger equation in Bose–Einstein condensates and fiber optics
Authors: Brugarino Tommaso , Sciacca Michele
Published: September 2010

In this paper, we investigate the integrability of an inhomogeneous nonlinear Schrödinger equation, which has several applications in many branches of physics, as in Bose–Einstein condensates and fiber optics. The main issue deals with Painlevé property (PP) and Liouville integrability for a nonlinear Schrödinger-type equation. Solutions of the integrable equation are obtained by means of the Darboux transformation. Finally, some applications on fiber optics and Bose–Einstein condensates are proposed (including Bose–Einstein condensates in three-dimensional in cylindrical symmetry).
Terahertz emission from InAs induced by photo-Dember effect: Hydrodynamic analysis and Monte Carlo simulations
Authors: Reklaitis Antanas
Published: September 2010

Terahertz emission from InAs excited by the femtosecond optical pulse is investigated. The hydrodynamic model is developed for the simplified analysis of the terahertz emission induced by the photo-Dember effect. The hydrodynamic model predicts that the amplitude of the transient photocurrent is proportional to the difference between the squared velocities of photoexcited electrons and holes. The predictions of the hydrodynamic model are compared to the results of the rigorous ensemble Monte Carlo simulations. The dependences of the intensity of terahertz emission on the optical fluence, on the photon energy, and on the optical pulse duration are studied. At low intensities of the optical pulse, the emitted terahertz energy is proportional to the power ranging between 3/2 and 2 of the optical pulse intensity. The emitted terahertz energy saturates at high intensities of the optical pulse. The spectral dependence of the terahertz emission from InAs is investigated. It is found that the intensity of terahertz emission profoundly depends on the optical pulse duration.
Simulations of luminescent solar concentrators: Effects of polarization and fluorophore alignment
Authors: McDowall S. , Johnson B. L. , Patrick D. L.
Published: September 2010

We model the effects of dye molecule alignment on the collection efficiency of luminescent solar concentrators (LSCs). A Monte Carlo model for photon transport in LSC’s is derived and utilized, which incorporates the effects of fluorescent-dye-molecular alignment and the subsequent control over absorption, emission, and propagation properties. We focus on the effects of molecular alignment statistics on photon absorption and subsequent emission, including polarization and propagation direction imparted by dipole direction, to model device light-capture efficiency, defined as the ratio of the amount of light reaching particular slab edges to that incident on a face. We find that modest control of alignment, coupled with reasonable and attainable emission-absorption dipole angles, can produce very large collection efficiencies for a range of device parameters. We note that efficiencies for small values of dye molecule Stoke’s shift may be made as large as those for homogeneous (unaligned) systems with large Stoke’s shift.
Broadband electron spin resonance at 4–40 GHz and magnetic fields up to 10 T
Authors: Schlegel C. , Dressel M. , van Slageren J.
Published: September 2010

A broadband electron spin resonance spectrometer is described which operates at frequencies between 4 and 40 GHz and can be used in superconducting magnets. A tunable cylindrical cavity is connected to a vector network analyzer via coaxial cables, and the radiation is fed into the cavity by a coupling loop. No field modulation is employed. Resonance frequencies below 14 GHz are obtained by inserting dielectrics with different permittivities into the cavity. The setup allows for measurements with the microwave magnetic field either parallel or perpendicular to the external field.
Double-quantum two-dimensional electronic spectroscopy of a three-level system: Experiments and simulations
Authors: Nemeth Alexandra , Milota Franz , Mančal Tomáš , Pullerits Tönu , Sperling Jaroslaw , Hauer Jürgen , Kauffmann Harald F. , Christensson Niklas
Published: September 2010

Double-quantum coherence two-dimensional (2Q2D) electronic spectroscopy is utilized to probe the dynamic fluctuations of electronic states in a solvated molecule at approximately twice the energy of the ground state bleach transition. The 2Q2D spectrum gives insight into the energetic position and spectral fluctuations (system-bath interaction) of the probed excited states. Combining it with single-quantum two-dimensional (1Q2D) electronic spectroscopy enables one to determine the strength of the excited state absorption transition and the relative detuning of electronic states, as well as the dynamics of the single-quantum coherence. To investigate the correlation of spectral fluctuations in different electronically excited states, we have carried out experiments on a solvated dye (Rhodamine 6G) with 23 fs pulses centered at the maximum of the linear absorption spectrum. The 2Q2D spectrum reveals three peaks of alternating signs with the major negative peak located at higher frequencies along the emission axis compared to the single positive peak. The 1Q2D spectrum, on the other hand, shows a negative peak stemming from excited state absorption at lower frequencies along the emission axis. Analysis of the signal in the homogeneous limit fails to account for this observation as well as the number of peaks in the 2Q2D spectrum. Employing a three-level model in which all time correlations of the third-order response function are accounted for via second-order cumulant expansion gives good agreement with both the 1Q2D and 2Q2D data. Furthermore, the analysis shows that the fluctuations of the probed electronic states are highly correlated, reflecting the modulation by a common nuclear bath and similarities in the nature of the electronic transitions.
On the relation between the microscopic structure and the sound velocity anomaly in elemental melts of groups IV, V, and VI
Authors: Greenberg Yaron , Yahel Eyal , Caspi El’ad N. , Beuneu Brigitte , Dariel Moshe P. , Makov Guy
Published: September 2010

The sound velocity of some liquid elements of groups IV, V, and VI, as reported in the literature, displays anomalous features that set them apart from other liquid metals. In an effort to determine a possible common origin of these anomalies, extensive neutron diffraction measurements of liquid Bi and Sb were carried out over a wide temperature range. The structure factors of liquid Sb and Bi were determined as a function of temperature. The structure of the two molten metals was carefully analyzed with respect to peak locations, widths, and coordination numbers in their respective radial distribution function. The width of the peaks in the radial distribution functions was not found to increase and even decreased within a certain temperature range. This anomalous temperature dependence of the peak widths correlates with the anomalous temperature dependence of the sound velocity. This correlation may be accounted for by increased rigidity of the liquid structure with temperature. A phenomenological correlation between the peak width and the sound velocity is suggested for metallic melts and is found to agree with available data for normal and anomalous elemental liquids in groups IV–VI.
Photodeterioration of the silicon nanocrystal emission
Authors: Koshel D. , Barba D. , Martin F. , Ross G. G.
Published: September 2010

Photoluminescence (PL) of silicon nanocrystals (Si-nc) is investigated as a function of exposure time for several laser intensities. Both a strong decrease in luminescence and an energy shift are observed during the illumination period. Decay analysis of the PL emission intensity indicates two timescales: a short timescale (<0.5 min), associated with reversible sample heating effects and a longer timescale (>5 min), attributed to an irreversible sample damage caused by the laser excitation. Both sample heating and damage shift the PL emission toward the red. These longer timescale variations can significantly influence the precision of both PL and optical gain measurements performed at average pumping intensities as low as ∼1 W cm−2. The complex evolution of the Si-nc spectra after a long recovery period indicates that the permanent degradation of the PL signal results from the activation of several sample damaging mechanisms, whose possible origins are discussed.
First-principles study of native defects in TlBr: Carrier trapping, compensation, and polarization phemomenon
Authors: Du Mao-Hua
Published: September 2010

First-principles calculations are carried out to study the native defect properties in TlBr. Three important results emerge: (1) the native defects are benign in terms of electron trapping because the low-energy defects do not induce electron traps; (2) the dominant defects in nearly stoichiometric TlBr are Schottky defects that pin the Fermi level near the midgap, leading to high resistivity; and (3) the calculated low diffusion barriers for several native defects show that ionic conductivity can occur at room temperature. The important impacts of these material properties on the room-temperature radiation detection using TlBr are discussed.
A procedure to determine the optimum imaging parameters for atomic/molecular resolution frequency modulation atomic force microscopy
Authors: Hosokawa Yoshihiro , Kobayashi Kei , Oyabu Noriaki , Matsushige Kazumi , Yamada Hirofumi
Published: September 2010

We propose a general procedure to determine the optimum imaging parameters (spring constant and oscillation amplitude) to obtain the optimum resolution in frequency modulation atomic force microscopy. We calculated the effective signal-to-noise ratio for various spring constants and oscillation amplitudes, based on the measurement of frequency shift and energy dissipation versus tip-sample distance curves, to find the optimum. We applied this procedure for imaging a lead phthalocyanine (PbPc) thin film on a MoS2(0001) substrate, and found that the optimum parameters were about 5 N/m and 20 nm, respectively. An improved signal-to-noise ratio was attained in a preliminary experiment using parameters which were close to the calculated optimum.
EXP6 fluids at extreme conditions modeled by two-Yukawa potentials
Authors: Krejčí Jan , Nezbeda Ivo , Melnyk Roman , Trokhymchuk Andrij
Published: September 2010

A two-Yukawa representation of the EXP6 fluids at supercritical temperatures and high pressures has been developed and examined using molecular simulations. A uniquely defined mapping of the repulsive part of the EXP6 potential curve onto the two-Yukawa potential is used. Two ranges of temperatures, one encountered in geochemical applications (Tgeo range) and the other at conditions of detonations (Tdet range), are considered and it is shown that the local structures of both fluids are practically identical. Deviations between the EXP6 and two-Yukawa potential functions at intermediate separations lead to differences in the thermodynamic properties of the two fluids at lower temperatures of the Tgeo range; at higher temperatures and in the high Tdet temperature range both the structural and thermodynamic properties of the EXP6 and two-Yukawa fluids are practically identical.
Loss compensation in external cloaks using a thin layer of gain media
Authors: Wang Jin , Dong Hui Yuan , Jiang Wei Xiang , Cui Tie Jun
Published: September 2010

Transformation optical devices based on the concept of complementary medium have attracted much attention due to their novel properties. A recent paper [H. Chen and C. T. Chan, Opt. Lett. 34, 2649 (2009)] showed a class of complementary medium in bipolar coordinates, which can render the object invisible at a distance. The prescription requires lossless materials composed of negative index medium (NIM), and a certain loss will cut off the cloaking effect of the device. In this paper, we suggest compensation to the lossy NIM by introducing gain media into such a device. For the realization of the whole cloaking device, we present an optimized compensation method to upgrade the function by adding a very thin layer of gain media in the surrounding medium. Numerical simulations demonstrate a dramatic improvement in the cloaking performance when the NIM is lossy.
Effect of interfacial reactions between atomic-layer-deposited HfO2 films and n-GaAs (100) substrate using postnitridation with NH3 vapor
Authors: Kim C. Y. , Kang Y. S. , Lee S. Y. , Cho M.-H. , Chung K. B. , Kim H. , Na S. , Lee H. J. , Yun H. J.
Published: September 2010

Using a variety of various physical measurements, the effects of postnitridation annealing using NH3 vapor on the interface between atomic-layer-deposited HfO2 films and n-GaAs (100) substrates were investigated. After the nitridation treatment, from x-ray absorption spectroscopy and high resolution x-ray photoemission spectroscopy data indicate that the incorporation of Ga oxides into HfO2 films was significantly suppressed during the annealing treatment, primarily because of chemical reactions at the interface between Ga2O3 and NH3. Microstructural analyses further confirmed that the HfO2 film was fully crystallized and a thin GaOxNy layer had been formed at the HfO2/GaAs interface during the annealing process. Compared with the energy band alignments before and after the annealing process, the valence band offsets and energy band gaps were not changed substantially, because the interfacial nitride layer effectively blocked the diffusion of Ga oxide into the film.
Bi
1
−
x
Sr
x
CuSeO
oxyselenides as promising thermoelectric materials
Authors: Zhao L. D. , Berardan D. , Pei Y. L. , Byl C. , Pinsard-Gaudart L. , Dragoe N.
Published: September 2010

p -type BiCuSeO, a layered oxyselenide composed of conductive (Cu2Se2)2− layers alternately stacked with insulating (Bi2O2)2+ layers, shows an enhancement of the electrical conductivity after substituting Bi3+ by Sr2+, from 470 S m−1 (BiCuSeO) to 4.8×104 S m−1 (Bi0.85Sr0.15CuSeO) at 293 K. Coupled to high Seebeck coefficients, this leads to promising values of the thermoelectric power factor that exceeds 500 μW m−1 K−2 at 873 K. Moreover, the thermal conductivity of these layered compounds is lower than 1 W m−1 K−1 at 873 K. Maximum ZT values reach 0.76 at 873 K, making this family promising for thermoelectric applications in the medium temperature range.
Left handed material based on amorphous ferromagnetic microwires tunable by dc current
Authors: García-Miquel H. , Carbonell J. , Sánchez-Dehesa J.
Published: September 2010

Tuning of the transmission characteristics of amorphous ferromagnetic microwires through a dc current is demonstrated. These structures are studied in the frequency region where they present double negative behavior. It is found that their frequency response shifts with small dc currents circulating along the wires. It is observed that the dc current tends to compensate and even cancels the resonant peak associated to the static magnetic field applied along the wire axis. The phenomenon behind these findings is discussed in terms of the torque exerted by the field created by the current on the plane perpendicular to the wire axis.