bluuebunny/crossref_metadata_2025 huggingface dataset:
Biosynthetic studies of the DSP toxin skeleton
Authors: Daranas Antonio H. , Fernández José J. , Norte Manuel , Gavín José A. , Suárez‐Gómez Blanca , Souto María L.
Published: March 2004

Marine toxins have drawn wide interest because their economical impact and disastrous effect upon the
shellfish industry and public health in many parts of the world. One of the most interesting group of substances of
marine toxins, from structural and pharmacological points of view are polyether compounds, which generally present a
great diversity in size and potent biological activities. The subject of this work was about to biosynthesis of okadaic
acid skeleton as leader as DSP toxins. Its biosynthesis attracts considerable attention since the carbon skeleton has
been shown to be synthesised via an unusual route. In this paper we report on stable isotope incorporation experiments
on DSP toxin in artificial cultures of dinoflagellate. The comparison of the degrees of incorporation in these samples
measured by different methods led to contradictory results. This implies that further experimental data is needed in
order to propose a logical biogenetic scheme. © 2004 The Japan Chemical Journal Forum and Wiley Periodicals, Inc.
Chem Rec 4: 1–9; 2004: Published online in Wiley InterScience
(www.interscience.wiley.com
) DOI 10.1002/tcr.10072
Towards the biaxial nematic phase through molecular design
Authors: Bruce Duncan W.
Published: March 2004

In this article, the search for the elusive biaxial nematic phase (NB) in liquid crystals
is considered. The structure of the phase is described along with theoretical and computational work which suggests
how it might be realised. An overview of the work of the Exeter group in this area is then given showing the different
approaches adopted and illustrating how one of these has led to a new type of amphiphilicity based on shape. © 2004
The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 4: 10–22; 2004: Published online in Wiley
InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.10073
Femtosecond laser‐induced microstructures in glasses and applications in micro‐optics
Authors: QIU JIANRONG
Published: March 2004

Femtosecond laser has been widely used in microscopic modifications to materials due to its ultra‐short laser pulse
and ultrahigh light intensity. When a transparent material e.g. glass is irradiated by a tightly focused femtosecond laser, the photo‐induced
reaction is expected to occur only near the focused part of the laser beam inside the glass due to the multiphoton processes. We observed
various induced structures e.g. color center defects, refractive index change, micro‐void and micro‐crack, in glasses after
the femtosecond laser irradiation. In this paper, we review the femtosecond laser induced phenomena and discuss the mechanisms of the observed
phenomena. We also introduce the fabrication of various micro‐optical components, e.g. optical waveguide, micro‐grating,
micro‐lens, fiber attenuator, 3‐dimensional optical memory by using the femtosecond laser‐induced structures. The
femtosecond laser will open new possibilities in the fabrication of micro‐optical components with various optical functions.
© 2004 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 4: 50–58; 2004: Published online in Wiley
InterScience (www.interscience.wiley.com
) DOI 10.1002/tcr.20006
Prospective evaluation of blood flow in the myometrium and uterine arteries in the puerperium
Authors: Van Schoubroeck D. , Van Den Bosch T. , Scharpe K. , Lu C. , Van Huffel S. , Timmerman D.
Published: March 2004

Objective

Heavy bleeding in the late postpartum has, in some cases, been attributed to subinvolution of the placental bed and enhanced myometrial vascularity (EMV) as seen on color Doppler imaging. The aim of this study was to investigate the incidence and spontaneous evolution of areas of enhanced vascularization over the whole thickness of the myometrium in asymptomatic women after uncomplicated term pregnancy.

Methods

This was a prospective descriptive study involving 93 consecutive women who were examined on day 3 (mean 2.6 ± 1.5) and at 6 weeks (mean 6.5 ± 1.3) after delivery following an uncomplicated term pregnancy. EMV was defined as the presence of marked flow over the full thickness of the myometrium reaching the uterine cavity. Doppler flow examination within the area of EMV and of both uterine arteries was performed.

Results

The mean patient age was 29.1 years and average parity was 1.7. The mean gestational age at delivery was 39.1 weeks. Areas of EMV were visualized in 50.5% of patients on day 3 vs. 3.9% at 6 weeks. None of the patients required therapy for bleeding problems. The mean pulsatility index and peak systolic velocity in the area of EMV on day 3 were 0.45 ± 0.30 and 0.37 ± 0.20 m/s, respectively. A consistent increase in vascular resistance and decrease in blood flow velocity was observed in both uterine arteries between day 3 and week 6.

Conclusions

Most areas of EMV reflect intermediate stages in the involution of the placental bed and do not cause abnormal postpartum bleeding. EVM is common in the puerperium, disappears spontaneously in the vast majority of cases, and does not warrant treatment if asymptomatic. Further research is needed to predict the rare cases in which subinvolution of the placental bed leads to heavy bleeding in the late postpartum. Copyright © 2004 ISUOG. Published by John Wiley & Sons, Ltd.
Disciplined, efficient, generalised folds for nested datatypes
Authors: Martin Clare , Gibbons Jeremy , Bayley Ian
Published: March 2004

Nested (or non-uniform, or non-regular) datatypes have recursive definitions in which the type parameter changes. Their folds are restricted in power due to type constraints. Bird and Paterson introduced
generalised folds
for extra power, but at the cost of a loss of efficiency: folds may take more than linear time to evaluate. Hinze introduced
efficient generalised folds
to counter this inefficiency, but did so in a pragmatic way: he did not provide categorical or equivalent underpinnings, so did not get the associated universal properties for manipulating folds. We combine the efficiency of Hinze’s construction with the powerful reasoning tools of Bird and Paterson’s.
Surgical Treatment of Barrett’s Esophagus: 1980‐2003
Authors: Csendes Attila
Published: March 2004

Barrett’s esophagus is a complication of long‐standing gastroesophageal reflux and can be a premalignant condition. The goals of surgical treatment, which were well summarized by DeMeester, have been increased and more detailed by us. They consist of (1) controlling symptoms of gastroesophageal reflux disease; (2) abolishing acid and duodenal reflux into the esophagus; (3) preventing or eliminating the development of complications; (4) preventing extension of or an increase in the length of intestinal metaplasia; (5) inducing regression of intestinal metaplasia to the cardiac mucosa; and (6) preventing progression to dysplasia, thereby inducing regression of low‐grade dysplasia and avoiding the appearance of an adenocarcinoma. We have reviewed 25 articles in the English‐language literature published from 1980 to 2003 dealing specifically with the surgical treatment of Barrett’s esophagus. In most of these papers too few patients were included, the follow‐up was less than 60 months, and the clinical success deteriorated with time. Acid reflux persists after surgery in nearly 35% of Barrett’s esophagus patients; and at 10 years after surgery duodenal reflux is present in 95%. Peptic ulcer, stricture, and erosive esophagitis are present in 15% to 30% late after surgery, and in 16% there is progression of the intestinal metaplasia. There is the appearance of low‐grade dysplasia in 6.0% and adenocarcinoma in 3.4%, and there is regression of low‐grade dysplasia in 45.0%. These results challenge the arguments supporting antireflux surgery for patients with Barrett’s esophagus: The clinical results are not optimal, no long‐lasting effect has been demonstrated, and it does not prevent the appearance of dysplasia or adenocarcinoma. An excellent alternative is acid suppression and a duodenal diversion procedure, which has had 91% clinical success for more than 5 years. This regimen has almost eliminated acid and duodenal reflux, and there has been no progression to dysplasia or adenocarcinoma. Moreover, in 60% of the patients with low‐grade dysplasia, regression to nondysplastic mucosa has occurred.
Problems and Prospects of Managing Thoracic Aortic Aneurysm at the Nnamdi Azikiwe University Teaching Hospital, Nnewi, Nigeria
Authors: Chianakwana Gabriel U. , Odike Maxy A.C. , Nwofor Alexander M.E.
Published: March 2004

The objective of this report is to highlight the problems encountered in managing thoracic aortic aneurysm in a third‐generation teaching hospital serving a purely rural community in the heartland of Anambra State, in the southeastern part of Nigeria. This report also proffers solutions aimed at assisting in providing better care for patients afflicted with this condition. From time to time, patients present with vascular diseases, including aneurysm, but the condition is only occasionally suspected and sparingly investigated. This is a report of two cases within the setting of the Nnamdi Azikiwe University Teaching Hospital (NAUTH), Nnewi Nigeria. After the death of these two patients, one of whom was a member of the staff of the hospital, post mortem examinations revealed that they had died of ruptured thoracic aortic aneurysm. Their medical records were retrieved from the Medical Records Department and reviewed with the aim of analyzing their clinical features and management in the light of the unexpected post‐mortem examination results. The survey of the patient records revealed that the diagnosis of thoracic aortic aneurysm was not suspected in either patient even though both had symptoms pointing to this condition. The staff member was a 55‐year old man and the other patient was a 31‐year old woman in her 30thweek of pregnancy. We conclude by drawing the attention of medical practitioners in our community to the fact that thoracic aortic aneurysms are probably more common than we thought. Only a high index of suspicion will lead to clinical diagnosis and treatment.
Aging and Wound Healing
Authors: Gosain Ankush , DiPietro Luisa A.
Published: March 2004

Impaired wound healing in the elderly presents a major clinical and economic problem. With the aging population growing in both number and percentage, the importance of understanding the mechanisms underlying age‐related impairments in healing is increased. Normal skin exhibits characteristic changes with age that have implications for wound healing. Additionally, the process of wound healing is altered in aged individuals. Although historically healing in the aged was considered defective, there is now consensus that healing in the elderly is delayed but the final result is qualitatively similar to that in young subjects.
Redox Processes Underlying the Vascular Repair Reaction
Authors: Leite Paulo F. , Liberman Marcel , Sandoli de Brito Fábio , Laurindo Francisco R.M.
Published: March 2004

Accumulating evidence indicates that vascular dysfunction in atherosclerosis, hypertension, and diabetes is either caused by or accompanied by oxidative stress in the vessel wall. In particular, the role of redox processes as mediators of vascular repair and contributors to post‐angioplasty restenosis is increasingly evident. Yet the pathophysiology of such complex phenomena is still unclear. After vascular injury, activation of enzymes such as NADPH oxidase leads to a marked increase in superoxide generation, proportional to the degree of injury, which rapidly subsides. Such early superoxide production is significantly greater after stent deployment, as compared to balloon injury. Recent data suggest the persistence of low levels of oxidant stress during the vascular repair reaction in neointimal and medial layers. Despite the compensatory increase in expression of iNOS and nNOS, nitric oxide bioavailability is reduced because of increased reaction rates with superoxide, yielding as by‐products reactive nitrogen/oxygen species that induce protein nitration. Concurrently, the activity of vascular superoxide dismutases exhibits a sustained decrease following injury. This decreased activity appears to be a key contributor to vasoconstrictive remodeling and a major determinant of the occurrence of nitrative/oxidative stress. Replenishment of superoxide dismutase (SOD), as well as treatment with vitamins C and E or the lipid‐lowering drug probucol and its analogs, led to decrease in constrictive remodeling and improved vessel caliber. Better understanding of the redox pathophysiology of vascular repair should help clarify the pathogenesis of many other vascular conditions and may provide novel therapeutic strategies to prevent vascular lumen loss.
Occurrence of the Indian genusHemibos(Bovini, Bovidae, Mammalia) at the Early–Middle Pleistocene transition in Italy
Authors: Martı́nez-Navarro Bienvenido , Palombo Maria Rita
Published: March 2004

The morphology of the horn-core structure and section shape of theBos galerianustype specimen, as well as the general anatomy of the frontal and occipital areas of the skull, suggest that the skull is better attributed to the Indian genusHemibos. This finding contributes to our understanding of faunal dispersal patterns into Europe at the Early–Middle Pleistocene transition.
Discourses of Exclusion: Reconceptualising Participation Amongst Young People
Authors: FERGUSSON ROSS
Published: March 2004

This paper considers how varying discourses of social exclusion have informed policies regarding young people's participation in education, training and employment. Drawing on a cohort study of over 800 16–18 olds, the research suggests that the binary categories of exclusion/inclusion, and marginalisation/participation grow less and less adequate as parameters for understanding changing patterns of post-16 participation and non-participation. It is argued that a range of statutory, structural, financial and social pressures to normalise participation produce forms of inclusion that are ephemeral and that carry very different meanings from those implied in discourses of exclusion. The paper gives a brief overview of the changing context in which participation needs to be understood, then presents evidence and analysis of young people's trajectories after 16. Some interpretations are offered of a wide range of meanings of participation, which suggest that old notions of transition to independence are unsustainable for a substantial minority of young people, and that patterns of participation are increasingly complex, have multiple significances, and carry the potential to mask inequalities and new forms of exclusion. These readings have major implications for how we conceptualise social exclusion, and for policy developments associated with it.
Child Protection and Risk-Management: The Death of Victoria Climbie
Authors: JOHNSON SHEENA , PETRIE STEPHANIE
Published: March 2004

This paper looks at the concepts of ‘risk’ and ‘safety culture’ within a Social Work context, specifically in relation to child protection. Discussion is made of the systemic and organisational issues that are apparent in many inquiries into child death from abuse, and the authors argue that these issues need to be given a higher profile to ensure avoidable tragedies do not occur as a result of organisational failure. The concept of ‘safety culture’ is described as a tool of best practice used by some organisations in the commercial sector to ensure their risk, for example communication failure, in relation to organisational issues is both understood and controlled. The parallels between an organisational breakdown resulting in a disaster and those relating to the breakdown of childcare services are outlined in relation to two high profile examples, the Challenger Space Shuttle disaster and the tragic death of Victoria Climbie respectively. The authors discuss how the lessons learnt from such disasters and the ways in which high risk commercial organisations give organisational issues such high priority can, and should be, successfully transferred into other sectors, namely Social Work and Child Protection services.
Social Policy Digest Online
Authors: Bennett Fran , Jones Ken
Published: March 2004

The Social Policy Digest went online in the summer of 2003. This means that the Digest, which used to be printed as part of the Journal of Social Policy, is now only available via the web.
The presence of written English on the streets of Rome
Authors: GRIFFIN JEFFREY L.
Published: March 2004

ENGLISH is a juggernaut whose sweep across the globe is marked not only by the ever-swelling ranks of those who speak it as a second language, but also by its intrusion into other languages and cultures. While far from omnipresent, English is seen and heard in enough contexts in non-English-speaking countries that social scientists must carefully explore its role alongside indigenous languages. This study, which focused on the city of Rome, examines one dimension of English as an invader – its presence on street signs, on store fronts, in shop windows, outside commercial and public buildings, in billboards and other street advertisements, and in graffiti. It takes a more expansive and comprehensive approach than previous studies in examining the use of English in a foreign locale, in order to get a better sense of how widespread it is on the streets of a non-English-speaking country and in what contexts it appears.
Do you put your eggs or your ex in your exit?
Authors: BULLEY MICHAEL
Published: March 2004

THIS ARTICLE is about the pronunciation of intervocalic x in English. I started thinking about it when I realized that in French (a language I am having to improve in, as I now live in France) the x in exercice is pronounced ‘gz’, whereas in the English equivalent it is ‘ks’. In fact, in all French words beginning ‘ex + vowel’ the x is voiced (‘gz’). There are other similar contrasts with English – exécuter, exigence, exosphère. While it might be instructive to compare the pronunciation of intervocalic x among several, or many, connected, or unconnected, languages, that sounds like a long work and I think it is possible to make some sense sticking only to English, with just an occasional glance elsewhere.
Social Policy and Social Capital: A Clear Case of Putting Merit before Method?
Authors: Roche Martin
Published: March 2004

The recent emergence of the term social capital into the vocabulary of policy makers in the UK is indicative of the community-led model which is currently being championed by New Labour. However, before the practical value (if any) of this particular ‘new’ idea can be realised, ways of measuring social capital which would make it ‘fit for purpose’ in the local policy setting need to be developed. The findings of one project, which set about measuring social capital in four West Midlands boroughs, provides the basis for a preliminary assessment of what a social capital-oriented tool may actually contribute to the development and implementation of policies at the local level.
The Human Rights Act 1998: A Bridge between Citizenship and Justice?
Authors: Johnson Nigel
Published: March 2004

This article discusses the implications of the Human Rights Act 1998 (HRA). It suggests that the HRA is designed to promote a classic liberal conception of political citizenship, which protects the individual from the exercise of arbitrary state power, and not to extend the role of the state as a welfare provider. It goes on to argue that the government has limited the effectiveness of the HRA by claiming that they are building a culture of rights and responsibilities whilst treating human rights as an issue for the courts rather than an issue for government and public authorities generally. The article concludes by discussing extending the HRA to include economic, social and cultural rights.
Work and Retirement Transitions: Changing Sociological and Social Policy Contexts
Authors: Phillipson Chris
Published: March 2004

The main argument of this paper is that retirement will retain its importance over the next few decades, despite pressure from governments to encourage workers to delay leaving paid employment. Retirement may prove especially difficult to reverse among the ‘baby boom’ cohorts where an expectation of withdrawing from work at earlier ages has become entrenched. The article examines the policy context influencing current debates. It then reviews data on retirement attitudes and trends in the employment of older workers. The paper concludes by arguing for a ‘broadening’ in the social institution of retirement, with the development of new types of social engagement in formal as well as informal spheres of activity.
Useful Sources
Authors: Platman Kerry
Published: March 2004

Web sites about age and employment issues have multiplied in recent years. This section focuses on web sites designed and administered by Government and independently funded bodies based in Europe, the United States and the United Kingdom.
Responding well to the challenge of an ageing and shrinking workforce. European Union policies in support of Member State efforts to Retain, Reinforce & Re-integrate Older Workers in employment
Authors: von Nordheim Fritz
Published: March 2004

In response to the ageing and shrinking of the working-age population, the European Union has agreed ambitious goals for raising the employment rate and the exit age of older workers. This article traces the development of EU policy approaches and presents EU-15 figures on the state of affairs. Progress so far has been modest, but EU policies are expected to facilitate the emergence of better regimes of age management within Member States. In turn, this will help Europe move towards its employment targets for the working population aged 55 to 64 years.
Shallow anisotropy in the Mediterranean mantle from surface waves
Authors: Marone F. , van der Lee S. , Giardini D.
Published: March 2004

We present new evidence for the existence of the Love‐Rayleigh discrepancy in the Mediterranean region and constrain the average polarization anisotropic structure of the Mediterranean mantle. We analysed regional Rayleigh and Love waveforms recorded at 3‐component broadband seismic stations. None of the 3‐component seismograms could be fit with a single 1D isotropic and smooth velocity model. However, satisfactory fits for individual Rayleigh and Love waveforms could often be obtained using realistic 1D velocity models. We used these 1D path‐average velocity structures to derive 3D S‐velocity models for the Mediterranean region. Our results show that Love waves require higher velocities (about 200 m/s) compared to Rayleigh waves between 30 and 120 km depth. We relate the observed anisotropy to lattice‐preferred orientation of crystallographic axes of elastically anisotropic minerals such as olivine.
Evaluation of cloud thermodynamic phase parametrizations in the LMDZ GCM by using POLDER satellite data
Authors: Doutriaux‐Boucher M. , Quaas J.
Published: March 2004

Realistic simulations of clouds are of uppermost importance for climate modelling using general circulation models. Satellite data are well suited to evaluate model parametrizations. In this study we use the Laboratoire de Météorologie Dynamique general circulation model (LMDZ). We evaluate the current LMDZ cloud phase parametrization, in which the repartition of condensed cloud water between liquid and ice is a function of the local temperature. Three parameters are used to derive a relation between liquid cloud water content and temperature, two of which are not physically based. We use the POLDER‐1 satellite data to infer more realistic parameters by establishing statistical relationships between cloud top thermodynamical phase and cloud top temperature, consistently in both satellite data and model results. We then perform a multitude of short model integrations and derive a best estimate for the lowest local temperature where liquid water can exist in a cloud (Tice = −32°C in our parametrization). The other parameter which describes the shape of the transition between ice and liquid water is also estimated. A longer simulation has then been performed with the new parameters, resulting in an improvement in the representation of the shortwave cloud radiative forcing.
Arctic Oscillation modulation of the Northern Hemisphere spring tropospheric ozone
Authors: Lamarque Jean‐François , Hess Peter G.
Published: March 2004

This study identifies the Arctic Oscillation (AO) signature on the interannual variability of tropospheric ozone, with an emphasis on spring ozone over the North American and European continents. The analysis is first performed on ozonesonde data. It is shown that the variability in AO explains up to 50% of the tropospheric ozone variability in the lower troposphere over North America during the spring months. Chemistry‐transport model simulations in which the meteorology varies from year to year, but the emissions and net stratospheric production of ozone remain the same show similar results. The model results indicate the role of the AO in modulating stratosphere‐troposphere exchange and in regulating the transport of ozone and its precursors from North America, Europe and Asia.
Strain accumulation across the Coast Ranges at the latitude of San Francisco, 1994–2000
Authors: Savage J. C. , Gan W. , Prescott W. H. , Svarc J. L.
Published: March 2004

A 66‐monument geodetic array spanning the Coast Ranges near San Francisco has been surveyed more than eight times by GPS between late 1993 and early 2001. The measured horizontal velocities of the monuments are well represented by uniform, right‐lateral, simple shear parallel to N29°W. (The local strike of the San Andreas Fault is ∼N34°W.) The observed areal dilatation rate of 6.9 ± 10.0 nstrain yr−1 (quoted uncertainty is one standard deviation and extension is reckoned positive) is not significantly different from zero, which implies that the observed strain accumulation could be released by strike‐slip faulting alone. Our results are consistent with the slip rates assigned by the Working Group on California Earthquake Probabilities [2003] to the principal faults (San Gregorio, San Andreas, Hayward‐Rodgers Creek, Calaveras‐Concord‐Green Valley, and Greenville Faults) cutting across the GPS array. The vector sum of those slip rates is 39.8 ± 2.6 mm yr−1 N29.8°W ± 2.8°, whereas the motion across the GPS array (breadth 120 km) inferred from the uniform strain rate approximation is 38.7 ± 1.2 mm yr−1 N29.0°W ± 0.9° right‐lateral shear and 0.4 ± 0.9 mm yr−1 N61°E ± 0.9° extension. We interpret the near coincidence of these rates and the absence of significant accumulation of areal dilatation to imply that right‐lateral slip on the principal faults can release the accumulating strain; major strain release on reverse faults subparallel to the San Andreas Fault within the Coast Ranges is not required.
Error analysis of continuous GPS position time series
Authors: Williams Simon D. P. , Bock Yehuda , Fang Peng , Jamason Paul , Nikolaidis Rosanne M. , Prawirodirdjo Linette , Miller Meghan , Johnson Daniel J.
Published: March 2004

A total of 954 continuous GPS position time series from 414 individual sites in nine different GPS solutions were analyzed for noise content using maximum likelihood estimation (MLE). The lengths of the series varied from around 16 months to over 10 years. MLE was used to analyze the data in two ways. In the first analysis the noise was assumed to be white noise only, a combination of white noise plus flicker noise, or a combination of white noise plus random walk noise. For the second analysis the spectral index and amplitude of the power law noise were estimated simultaneously with the white noise. In solutions where the sites were globally distributed, the noise can be best described by a combination of white noise plus flicker noise. Both noise components show latitude dependence in their amplitudes (higher at equatorial sites) together with a bias to larger values in the Southern Hemisphere. In the regional solutions, where a spatially correlated (common mode) signal has been removed, the noise is significantly lower. The spectral index of the power law in regional solutions is more varied than in the global solutions and probably reflects a mixture of local effects. A significant reduction in noise can be seen since the first continuous GPS networks began recording in the early 1990s. A comparison of the noise amplitudes to the different monument types in the Southern California Integrated GPS Network suggests that the deep drill braced monument is preferred for maximum stability.
Geodetic effects of the ocean response to atmospheric forcing in an ocean general circulation model
Authors: de Viron O. , Boy J.‐P. , Goosse H.
Published: March 2004

We have adapted the Coupled Large‐scale Ice‐Ocean (CLIO) model in order to include atmospheric pressure forcing in addition to the classical atmospheric forcing (heat and freshwater fluxes and wind stress). We have compared the modeled bottom pressure to in situ bottom pressure measurements and also to another ocean model. We have computed the induced effects on Earth orientation parameters (polar motion and nutations) and also on Earth time‐variable gravity field. We show that the response of the ocean to atmospheric pressure forcing has geodetic consequences well above the precision level and that the response of CLIO seems reasonable with respect to the few data sets we can compare with. We also show that the results obtained from the model improve the modeling of polar motion.
The formation of submarine gullies by turbidity currents
Authors: Izumi N.
Published: March 2004

A mathematical model of the formation of submarine gullies due to turbidity currents is presented in this study. A linear stability analysis is performed with the use of layer‐averaged momentum equations of turbidity currents, a dispersion equation of suspended sediment, and the Exner equation extended for the seabed subject to erosion and deposition due to turbidity currents. The analysis shows that the dominant gully spacing is of the order of 1500–8000 times the Richardson‐critical layer thickness of turbidity currents. Evaluating the Richardson‐critical layer thickness to be of the order of 0.1–1.0 m, the spacing of submarine gullies is of the order of 150–8000 m. According to observations, the spacing of submarine gullies ranges from a few hundred meters to a few kilometers. The theoretical results are found to be consistent with the observations.
Modeling of passive microwave responses in convective situations using output from mesoscale models: Comparison with TRMM/TMI satellite observations
Authors: Wiedner Martina , Prigent Catherine , Pardo Juan R. , Nuissier Olivier , Chaboureau Jean‐Pierre , Pinty Jean‐Pierre , Mascart Patrick
Published: March 2004

Passive microwave observations are sensitive to the whole hydrometeor column, in contrast to infrared and visible observations, which essentially sense cloud tops. Therefore passive microwave observations are a very promising tool to study the internal structure of precipitating clouds. A microwave radiative transfer model (Atmospheric Transmission at Microwaves (ATM)) has been developed to accurately simulate brightness temperature TB fields using output from nonhydrostatic mesoscale atmospheric model, Meso‐NH, simulations. The radiative transfer code takes the detailed description of the hydrometeor properties (as simulated by the Meso‐NH model) into account. The sensitivity of the predicted brightness temperature TB to the hydrometeor properties is carefully analyzed. Depending on the frequency, the passive microwave simulations show different sensitivities to the hydrometeor and surface properties: The low frequencies (10–30 GHz) sense essentially the surface properties and the liquid water column, whereas the higher frequencies (30–90 GHz) are most sensitive to the large icy hydrometeors (graupel and snow). TB simulations are generated for two real convective situations studied with Meso‐NH: Hurricane Bret on 22–23 August 1999 in the Gulf of Mexico and a South Atlantic Convergence Zone case off the Brazilian coast on 6–7 February 2001. The radiative transfer simulations are compared to the corresponding Tropical Rainfall Measuring Mission (TRMM) Microwave Instrument (TMI) observations on board TRMM, at 10.65, 19.35, 22.24, 37, and 85.5 GHz. To our knowledge, no direct comparisons between simulated TB and satellite observations had been conducted before for a systematic evaluation of the mesoscale cloud models. An overall good agreement is obtained for both situations, especially for the second one. At high frequencies the agreement is particularly remarkable, given the high sensitivity of these frequencies to the particle characteristics, especially in the ice phase. This result gives us strong confidence not only in the radiative transfer model but also in the bulk microphysical scheme of Meso‐NH.
A revised water vapor product for the Stratospheric Aerosol and Gas Experiment (SAGE) II version 6.2 data set
Authors: Thomason Larry W. , Burton Sharon P. , Iyer Nina , Zawodny Joseph M. , Anderson John
Published: March 2004

The Stratospheric Aerosol and Gas Experiment (SAGE) II water vapor retrieval process has been updated to reflect a new understanding of the instrument performance. Primarily, this is reflected in a shifted spectral response for the primary water channel near 935 nm for the period after January 1986. In addition, the water vapor and ozone spectroscopy, aerosol clearing process, and error estimation have been updated. The end result is that the measurement bias observed in version 6.1 and earlier versions has been effectively eliminated. The sensitivity to aerosol has been reduced, so that the recommended upper limit for usable water vapor is now 3 × 10−4 km−1 in 1020‐nm aerosol extinction. The comparable value for version 6.1 was ∼2 × 10−5 km−1, or 10 times more sensitive than in the new version. The impact of the channel drift on the retrieved water vapor relative to the simple model employed in this version will be difficult to separate from geophysical change, and therefore caution is recommended in evaluating trends derived from this data set.
Evaluating the use of the massive coral Diploastrea heliopora for paleoclimate reconstruction
Authors: Bagnato Stefan , Linsley Braddock K. , Howe Stephen S. , Wellington Gerard M. , Salinger Jim
Published: March 2004

To date, coral‐based paleoclimate research in the Pacific has primarily utilized core samples from the genus Porites and has been most successful reconstructing past variability on interannual timescales, particularly the El Niño Southern Oscillation (ENSO). The Indo‐Pacific coral genus Diploastrea, however, owing to its slower extension rate, denser structure, and longer lifespan, can potentially preserve geochemical proxy records 2–3 times longer than Porites cores of the same length. Before its potential can be realized, Diploastrea must first be calibrated and its climate signal assessed. We present oxygen isotope (δ18O) and Sr/Ca results from two Diploastrea cores collected in Fiji (16°49′S, 179°14′E) that allow for simultaneous evaluation of this coral's paleoclimatic utility and the reproducibility of each tracer at this site. Comparison to a Porites record from the same location allows for further evaluation of Diploastrea as a paleoclimatic archive. We demonstrate that Diploastrea's septal and columellar material yield similar δ18O‐SST relationships and that despite some sacrifice of the seasonal δ18O amplitude, bulk sampling of either region is satisfactory for resolving interannual and lower frequency modes of climatic variability. Therefore paleoclimate reconstructions employing either a septal or columellar sampling regime of this genus may be useful at filling in spatial and temporal sampling gaps which currently hinder the reconstruction of long‐term changes in major climate fields in the western Pacific.
Hydraulic geometry and the nonlinearity of the network instantaneous response
Authors: Paik Kyungrock , Kumar Praveen
Published: March 2004

We postulate that the spatial variability in flow velocity in a basin, arising from the systematic downstream variation of celerity, may explain the observed nonlinear rainfall‐runoff relationships. This is based on the argument that different rainfall excess rates will produce different velocity fields in a basin due to the nonlinear relation between velocity and flow. In particular, we show that if the mean velocity V varies with flow Q as V ∝ Qm, then the time to peak tp and the peak f(tp) of the network instantaneous response function (IRF) vary as tp ∝ ie−m and f(tp) ∝ ie+m, where ie is the rainfall excess rate.
Spacecraft and Ground Anomalies Related to the October‐November 2003 Solar Activity
Authors: Webb David F. , Allen Joe H.
Published: March 2004

During two weeks in late October and early November 2003, a series of large solar events led to high levels of energetic particles in geospace and produced overlapping large geomagnetic storms on 28‐30 October. These storms caused effects ranging from power grid failures to satellite shutdowns. A Japanese satellite was lost completely, the U. S. Federal Aviation Administration issued their first‐ever high radiation dosage alert for high‐altitude aircraft, and astronauts in the International Space Station had to retreat into their heavily shielded service module.
High Throughput Cryopreservation of 140 000 Physcomitrella patens Mutants
Authors: Schulte J. , Reski R.
Published: March 2004

Abstract: A high throughput protocol was established to preserve 140 000 mutants of a moss, Physcomitrella patens, a model plant for functional genomics studies, over liquid nitrogen. Regarding the reliable long‐term storage of diverse mutant phenotypes, as well as time and cost effectiveness, each working step was optimized: 1) plant preparation, 2) freezing regime, cryogenic conditions, 3) regrowth after thawing. A prerequisite for maximum regrowth was a 1‐week preculture of chopped plant material on a supplemented medium prior to freezing. Cryo vials as preculture vessels resulted in identical regrowth rates, compared to petri dishes. The cryo vial type had a significant influence on regrowth rates. A cooling rate of ‐ 1 °C/min down to ‐ 35 °C with a 10 min holding time before transferring plants to ‐ 152 °C was the most suitable freezing regime. This protocol allows a cryopreservation of 1100 plants during a 5‐day working week, practicable by one person. For more than 650 cryopreserved mutants a maximum regrowth rate of 100 % was obtained, independently of mutant phenotypes.
Molecular Phylogeography of the Moss Tortula muralis Hedw. (Pottiaceae) Based on Chloroplast rps4 Gene Sequence Data
Authors: Werner O. , Guerra J.
Published: March 2004

Abstract: Tortula muralis is a moss species of cosmopolitan distribution, for which we present chloroplast rps4 sequence data. The sequences provided a sufficiently high degree of divergence (h = 0.878, θ= 0.00989 ± 0.0000106, a total of 18 haplotypes for 49 accessions) for the degree of differentiation between regions from different continents to be investigated. In fact, 18.53 % of the variation found corresponded to differences between these regions, while 81.43 % was attributed to intra‐region differences. Only the Japanese area differed significantly from other regions. Some haplotypes are found on several continents, while others are restricted to certain areas. Six of the seven sequenced plants from Japan belong to a haplotype only found there. The phylogenetic analysis suggests that Tortula muralis might be paraphyletic, with Tortula vahliana nested within the Tortula muralis clade. At present, it is not clear whether gene flow between the different clades of Tortula muralis is a continuing process or whether Tortula muralis is an example of cryptic speciation.
Geographic Distribution and Recombination of Genomic Fragments on the Short Arm of Chromosome 2 ofArabidopsis thaliana
Authors: Schmuths H. , Hoffmann M. H. , Bachmann K.
Published: March 2004

Abstract:Range expansion from Pleistocene refugia and anthropogenic influences contribute to the present distribution pattern ofArabidopsis thaliana.We scored a genome‐wide set of CAPSs and found two markers with an east‐west geographic distribution across the Eurasian range of the species. Regions around the two SNPs were sequenced in 98 accessions, including newly collected plants from Middle Asia and Western Siberia. These regions correspond to a gene (∼ 1500 bp) and a non‐coding region (∼ 500 bp) 300 kbp apart on chromosome 2. Nucleotide diversities, π, of the two sequenced fragments were 0.0032 and 0.0130. The haplotypes of both sequences belonged to one of two groups: a rather uniform “Asian” and a more variable “European” haplotype group, on the basis of non‐disjunct clusters of SNPs. Recombination between “Asian” and “European” haplotypes occurs where they meet. Especially in the “European” haplotype, many rare SNP variants representing independent mutations are scattered among the shared haplotype‐specific SNPs. This agrees with previous suggestions of two large haplotype groups inA. thalianaand the post‐glacial colonization of central Europe from the east and the west. A clear correlation between climatic factors and the haplotype distribution may reflect the dispersal history rather than local climate adaptation. The pattern of SNP variation within the contiguous sequences explains why only a minority of SNPs selected across the genome show evidence of this geographic pattern.
Process Improvement (PI) Programs and Information Systems: A Cross-Case Analysis of Impact
Authors: Cunningham Joseph , Finnegan Patrick
Published: March 2004

While much research has examined the use of information technology within process improvement (PI) programs, there has been a paucity of research examining the impact of such programs on information systems (ISs). The purpose of this study is to investigate the impact of PI programs on ISs. The study involves case studies in four organizations that have implemented PI programs. The findings indicate that changes in ISs were not envisaged as being central to the PI programs. However, the implementation of the PI programs had a significant effect on the roles and responsibilities of those people impacted by the program. Information requirements changed as a consequence of these responsibility changes. ISs were found to make a significant contribution to meeting these new information requirements.
Bridging Broadband Internet Divides: Reconfiguring access to Enhance Communicative Power
Authors: Dutton William H , Gillett Sharon Eisner , McKnight Lee W , Peltu Malcolm
Published: March 2004

Government and industry initiatives to stimulate the diffusion of high-performance broadband telecommunications links have given a fresh impetus to debates over the social and economic implications of the growing use of the Internet and other information and communication technologies (ICTs). This paper analyses how outcomes tied to ICT innovation are shaped by choices about whether and how to use, or not use, the technology to reconfigure access to people, services, information and technologies in ways that significantly change the communicative power of individuals, communities, organisations, nations and regions. It explains why these outcomes are not predetermined by the technology, but unfold over time through the complex interplay among many actors, in many arenas. A framework is presented to assist in addressing the issue of digital divides and other areas of research, policy and practice affected by the design and use of broadband Internet and related ICTs.
On the influence of semirigid environments on proton transfer along molecular chains
Authors: Zoete Vincent , Meuwly Markus
Published: March 2004

The dynamics of proton transfer along ammonia chains (chemical composition NxH3x+1+, x=2, 4, and 6) in a constraining environment is investigated by ab initio molecular dynamics simulations. A carbon nanotube of defined length and diameter is used as an idealized constraining environment such that the ammonia chain is forced to maintain its quasilinear geometry. It is found that, although the energetics of proton transport shows considerable energetic barriers, proton translocation along the wire is possible at finite temperature for all chain lengths studied. The proton transport involves rotational reorientation of the proton-carrying ammonia molecule. High level ab initio calculations (MP2/aug-cc-pVTZ) yield barriers for internal rotation of 9.1 kcal/mol for NH4+–NH3 and 11.7 kcal/mol for OH3+–OH2, respectively. The infrared spectrum calculated from the dipole–dipole autocorrelation function shows distinct spectral features in the regions (2000–3000 cm−1) where the NHN proton transfer mode is expected to absorb. Assigning moderate opposite total charges between 0.002 and 0.2e to the carbon atoms at the end caps of the nanotube leads to a considerable speedup of the proton transfer.
Analytic second derivatives for general coupled-cluster and configuration-interaction models
Authors: Kállay Mihály , Gauss Jürgen
Published: March 2004

Analytic second derivatives of energy for general coupled-cluster (CC) and configuration-interaction (CI) methods have been implemented using string-based many-body algorithms. Wave functions truncated at an arbitrary excitation level are considered. The presented method is applied to the calculation of CC and CI harmonic frequencies and nuclear magnetic resonance chemical shifts up to the full CI level for some selected systems. The present benchmarks underline the importance of higher excitations in high-accuracy calculations.
Interaction of atomic hydrogen with single-walled carbon nanotubes: A density functional theory study
Authors: Barone Verónica , Heyd Jochen , Scuseria Gustavo E.
Published: March 2004

We have studied the interaction of atomic hydrogen with (5,5) and (10,0) single-walled carbon nanotubes (SWNT) using density functional theory. These calculations use Gaussian orbitals and periodic boundary conditions. We compare results from the local spin density approximation, generalized gradient approximation (GGA), and hybrid density functionals. We have first kept the SWNT geometric structure fixed while a single H atom approaches the tube on top of a carbon atom. In that case, a weakly bound state with binding energies from −0.8 to −0.4 eV was found. Full geometry relaxation leads to a strong SWNT deformation, weakening the nearest C–C bonds and increasing the binding energy by about 1 eV. Full hydrogen coverage of the (5,5) SWNT converts this metallic nanotube into an insulator with a band gap of 3.4 eV for the GGA functional and 4.8 eV for the hybrid functional. Hybrid functionals perform similar to pure density functional theory functionals for the calculation of binding energies while band gaps critically depend on the functional choice.
Intramolecular vibrational energy redistribution in the highly excited fluoroform molecule: A quantum mechanical study using the multiconfiguration time-dependent Hartree algorithm
Authors: Iung Christophe , Gatti Fabien , Meyer Hans-Dieter
Published: March 2004

The present paper is devoted to a detailed study of the intramolecular vibrational energy redistribution in fluoroform initiated by a local mode excitation of the CH stretch [nνCH (n=1,…,4)]. All nine internal degrees of freedom are explicitly taken into account and the full quantum mechanical simulation is performed by means of the multiconfiguration time-dependent Hartree algorithm. The existence of different time scales considerably complicates the dynamics. The mode-to-mode energy transfer is analyzed by calculating the evolution of the partial energies of all vibrational modes. This study emphasizes the crucial role played by the two-dimensional FCH bending modes which act as an energy reservoir. The fast energy flow into these bending modes significantly hinders an energy flow from the CH chromophore. Finally, our results are compared with those obtained previously with the wave operator sorting algorithm approach.