bluuebunny/crossref_metadata_2025 huggingface dataset:
Evidence that rehydrated, lyophilized red blood cells are sufficiently deformable for normal microcirculation transit
Authors: Fischer Thomas H. , Robbins Mary E. , Bode Arthur P. , Nichols Timothy C. , Bellinger Dwight E. , Schoenfisch Mark H.
Published: November 2004

A method was developed for the preparation of rehydratable lyophilized red blood cells (RL RBCs) that hold promise as cell‐based oxygen carriers for transfusion medicine. The maintenance of normal cellular deformability is essential for the successful development of cell‐based oxygen delivery systems. Improper deformability of RBCs can lead to hemolysis if too fragile or microvascular occlusion if too rigid. We developed an aldehyde stabilization method that is based on the use of paraformaldehyde polymers that complement the function of spectrin as a structural unit with conformational flexibility. Three types of in vitro deformability studies (filter transit, pipette aspiration, and atomic force microscopy) and in vivo intravital microscopy were performed to characterize the deformability of RL RBCs. When considered with safety data from previously reported studies in dogs, the results of these studies indicate that paraformaldehyde‐modified RL RBCs have visco‐elastic deformability properties that are in the nonpathological range. Microsc. Res. Tech. 65:62–71, 2004. © 2004 Wiley‐Liss, Inc.
Terminal nerve and vision
Authors: Behrens U. , Wagner H.‐J.
Published: November 2004

The vertebrate retina receives efferent input from different parts of the central nervous system. Efferent fibers are thought to influence retinal information processing but their functional role is not well understood. One of the best‐described retinopetal fiber systems in teleost retinae belongs to the terminal nerve complex. Gonadotropin‐releasing hormone (GnRH) and molluscan cardioexcitatory tetrapeptide (FMRFamide)‐containing fibers from the ganglion of the terminal nerve form a dense fiber plexus in the retina at the border of the inner nuclear and inner plexiform layer. Peptide‐containing fibers surround and contact perikarya of dopaminergic interplexiform cells in teleost retina. In vitro experiments demonstrated that exogenously supplied GnRH mediates dopaminergic effects on the membrane potential and on the morphology of dendritic tips (spinules) of cone horizontal cells. These effects can be specifically blocked by GnRH‐antagonists, indicating that the release of dopamine and dopamine‐dependent effects on light adaptation of retinal neurons are affected by the terminal nerve complex. Recent data have shown that olfactory information has an impact on retinal physiology, but its precise role is not clear. The efferent fiber of the terminal nerve complex is one of the first retinopetal fiber systems for which the sources of the fibers, their cellular targets, and several physiological, morphological, and behavioral effects are known. The terminal nerve complex is therefore a model system for the analysis of local information processing which is influenced by a distinct fiber projection. Microsc. Res. Tech. 65:25–32, 2004. © 2004 Wiley‐Liss, Inc.
Automatic segmentation of diatom images for classification
Authors: Jalba Andrei C. , Wilkinson Michael H.F. , Roerdink Jos B.T.M.
Published: November 2004

A general framework for automatic segmentation of diatom images is presented. This segmentation is a critical first step in contour‐based methods for automatic identification of diatoms by computerized image analysis. We review existing results, adapt popular segmentation methods to this difficult problem, and finally develop a method that substantially improves existing results. This method is based on the watershed segmentation from mathematical morphology, and belongs to the class of hybrid segmentation techniques. The novelty of the method is the use of connected operators for the computation and selection of markers, a critical ingredient in the watershed method to avoid over‐segmentation. All methods considered were used to extract binary contours from a large database of diatom images, and the quality of the contours was evaluated both visually and based on identification performance. Microsc. Res. Tech. 65:72–85, 2004. © 2004 Wiley‐Liss, Inc.
Cover Picture: Macromol. Rapid Commun. 23/2004
Authors: Furuhashi Yukiko , Nakayama Atsushi , Monno Teruo , Kawahara Yutaka , Yamane Hideki , Kimura Yoshiharu , Iwata Tadahisa
Published: November 2004

Cover: The picture on the cover shows a lozenge‐shaped lamellar crystal of poly‐(p‐dioxanone) (PPDX) crystallized isothermally from 1,4‐butanediol dilute solution. The lozenge‐shaped lamellar crystal shows a well‐resolved electron diffraction pattern as an inset. The fiber X‐ray diffraction pattern indicates that PPDX crystallizes in a 21 helix conformation. PPDX is currently of interest for medical devices and pharmaceutical applications not only because of its biodegradability and bioabsorbability, but also because of its processability.

Further details can be found in the Communication by Y. Furuhashi, A. Nakayama, T. Monno, Y. Kawahara, H. Yamane,* Y. Kimura, and T. Iwata on page 1943.
Transcriptional activation of the membrane‐bound progesterone receptor (mPR) by dioxin, in endocrine‐responsive tissues
Authors: Selmin Ornella , Thorne Patricia A. , Blachere Francoise M. , Johnson Paula D. , Romagnolo Donato F.
Published: November 2004

We originally identified the membrane‐bound progesterone receptor (mPR) using a screening for genes differentially expressed in liver of rats exposed to dioxin. Recent findings have suggested a role for the mPR in sperm cells, ovary, and brain; however, its mechanisms of action are largely unknown. In this study, we examined the expression pattern of the mPR in liver of rats exposed to dioxin and identified possible mechanisms of its regulation. We observed that mPR expression was induced by dioxin, but was also dependent on the hormonal responsiveness of the tissue. In particular, in male, but not female liver, dioxin induced the expression of the mPR. However, in control, untreated female liver the level of mPR transcript was higher than in control males. Moreover, in breast cancer cells MCF‐7 dioxin induced mPR expression. Promoter studies using the luciferase assay indicated that a fragment of ∼350 bp of the mPR promoter was able to induce luciferase activity in the presence of dioxin, suggesting that the presumptive XREs sites contained in this mPR promoter region are responsive to dioxin. Analysis of mPR protein level confirmed the results observed at the RNA level, both in rat liver and MCF‐7 cells. Taken together, these observations suggest the existence of a novel cross‐talk between steroid and aromatic hydrocarbon receptors (AhR), and underline the importance of the mPR as a mediator of physiologic effects of the sex hormones. Mol. Reprod. Dev. 70: 166–174, 2005. © 2005 Wiley‐Liss, Inc.
Chromatin organization and basic nuclear proteins in the male germ cells of Rana tigerina
Authors: Manochantr Sirikul , Sretarugsa Prapee , Chavadej jittipan , Sobhon Prasert
Published: November 2004

The process of chromatin condensation during spermiogenesis in Rana tigerina is similar to the heterochromatization in somatic cells, where 30 nm fibers are coalesced together into a dense mass in spermatozoa without changing their initial size and nucleosomal organization. This conclusion was supported by the finding that the full set of core histones (H2A, H2B, H3, H4) are still present in sperm chromatin, but histone H1 is replaced by its variant, H1V. Rabbit anti‐sera were raised against histone H3, H1, H1V, and H5 (H1 variant in chick erythrocyte). Anti‐histone H1 antiserum cross‐reacted with histone H1V, which implied the presence of a common epitope. Anti‐histone H1V and H5 also showed cross‐reaction with each other but not with histone H1, which implied the presence of a common epitope not shared by histone H1. Immunocytochemical studies, using the above antibodies as probes, showed that histones H3 is present in all steps of spermatogenic and spermiogenic cells, and somatic cells including red blood cells, Sertoli cells, and Leydig cells, while histone H1 is present in all of the cells mentioned except in spermatozoa where it is replaced by histone H1V. Histone H1V appears in the early spermatids starting from spermatid 1 (St1), and it persists throughout the course of spermatid differentiation into spermatozoa. Histone H1V is also found in chromosomes of metaphase spermatocyte and red blood cells. Thus histone H1V may cause the final and complete condensation of chromatin in Rana spermatozoa, a process which is similar to the heterochromatization occurring in somatic cells such as metaphase chromosome and chick erythrocyte nucleus. Mol. Reprod. Dev. 70: 184–197, 2005. © 2005 Wiley‐Liss, Inc.
Participation of the nonreducing terminal β‐galactosyl residues of the neutral N‐linked carbohydrate chains of porcine zona pellucida glycoproteins in sperm–egg binding
Authors: Yonezawa N. , Amari S. , Takahashi K. , Ikeda K. , Imai F.L. , Kanai S. , Kikuchi K. , Nakano M.
Published: November 2004

The zona pellucida (ZP) surrounding the mammalian oocyte is composed of three glycoprotein components (ZPA, ZPB, and ZPC). Mammalian sperm bind to carbohydrate chains of a ZP glycoprotein in the initial phase of fertilization. Sperm‐ligand carbohydrate chains have been characterized in mouse, cow, and pig. In pigs, triantennary/tetraantennary neutral complex‐type chains from ZPB/ZPC mixture possess stronger sperm‐binding activity than those of biantennary chains (Kudo et al., 1998: Eur J Biochem 252:492–499). Most of these oligosaccharides have β‐galactosyl residues at the nonreducing ends. This study used two in vitro competition assays to investigate the participation of the nonreducing terminal β‐galactosyl residues of the ligand active chains in porcine sperm binding. The removal of the nonreducing terminal β‐galactosyl residues from either the ligand active carbohydrate chains or endo‐β‐galactosidase‐digested glycoproteins significantly reduced their inhibition of sperm–egg binding, indicating that the β‐galactosyl residues at the nonreducing ends are involved in porcine sperm–egg binding. A correlation between the sperm‐binding activity and in vitro fertilization rate is also presented. Mol. Reprod. Dev. 70: 222–227, 2005. © 2005 Wiley‐Liss, Inc.
A network flow algorithm to minimize beam‐on time for unconstrained multileaf collimator problems in cancer radiation therapy
Authors: Ahuja Ravindra K. , Hamacher Horst W.
Published: November 2004

In this article, we study the modulation of intensity matrices arising in cancer radiation therapy using multileaf collimators. This problem can be formulated by decomposing a given m × n integer matrix into a positive linear combination of (0, 1) matrices with the strict consecutive 1's property in rows. We consider a special case in which no technical constraints have to be taken into account. In this situation, the rows of the intensity matrix are independent of each other and the problem is equivalent to decomposing m intensity rows—independent of each other—into positive linear combinations of (0, 1) rows with the consecutive 1's property. We demonstrate that this problem can be transformed into a minimum cost flow problem in a directed network that has the following special structures: (1) the network is acyclic; (2) it is a complete graph (that is, there is an arc (i, j) whenever i < j); (3) each arc cost is 1; and (4) each arc is uncapacitated (that is, it has infinite capacity). We show that using this special structure, the minimum cost flow problem can be solved in O(n) time. Because we need to solve m such problems, the total running time of our algorithm is O(nm), which is an optimal algorithm to decompose a given m × n integer matrix into a positive linear combination of (0, 1) matrices. © 2004 Wiley Periodicals, Inc. NETWORKS, Vol. 45(1), 36–41 2005
Polypropylene reactor mixture obtained with homogeneous and supported catalysts
Authors: Bastos Queli Cruz , Marques Maria De Fátima Vieira
Published: November 2004

Propylene polymerizations were performed with homogeneous ϕ2C(Flu)(Cp)ZrCl2 and SiMe2(Ind)2ZrCl2 catalyst mixtures and with mixtures supported on the zeolite acid mordenite. The polymerizations were performed in toluene and hexane/triisobutylaluminum at different temperatures and Al(MAO)/Zr concentration ratios. The effects of these variables on the catalyst activity were investigated with statistical experimental planning. The average molecular weights, molecular weight distributions, melting temperatures, and crystallinities of the obtained polymers were examined. The results showed lower activities for the homogeneous catalyst mixture than for the isolated systems. On the other hand, high activities were obtained for the syndiospecific heterogeneous system, but very low values were obtained for the supported isospecific metallocene, although both catalysts were prepared under the same conditions. The supported binary system showed intermediary catalyst activity in comparison with the syndiospecific and isospecific supported catalysts. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 263–272, 2005
Sizing of throttling device for gas/liquid two‐phase flow part 1: Safety valves
Authors: Diener Ralf , Schmidt Jürgen
Published: November 2004

The calculation of the mass flow rate through throttling devices is difficult when handling two‐phase flow, especially when boiling liquids flow into these fittings. Safety valves are typically oversized by a significant extent, if sizing methods like the ω‐method (originally developed by J. Leung), are used in case of low‐quality inlet flow. Within this method the boiling delay of the liquid and the influence of the boiling delay on the mass flow rate are not considered. In this paper the HNE‐DS model is proposed, where the compressibility coefficient ω is extended by adding a boiling delay coefficient. It includes the degree of thermodynamic nonequilibrium at the start of the nucleation of small mass fractions of vapor upstream of the fitting.

In Part 1 the sizing of safety valves is described. Additionally, the derivation of the HNE‐DS method is given in detail. Part 2 considers the mass flow rate through short nozzles, orifices, and control valves. The HNE‐DS model can be used for all those fittings. A comparison with experimental results on safety valves with steam/water and air/water flow has emphasized the excellent accuracy of the new model. © 2004 American Institute of Chemical Engineers Process Saf Prog, 2004
Naturkatastrophen und Klimaänderung — und ihre Folgen für die Versicherungswirtschaft
Authors: Berz Gerhard
Published: November 2004

Die Schadenbelastungen aus Naturkatastrophen haben gerade in den letzten Jahren — und gerade für die Versicherungswirtschaft — dramatische Ausmaße angenommen. Der Vergleich der letzten 10 Jahre mit den 60er Jahren zeigt: Die volkswirtschaftlichen Schäden sind auf das Siebenfache, die versicherten sogar auf das fast Vierzehnfache hochgeschnellt (vgl. Abb. 1). Wobei sich diese Angaben auf so genannte „große”︁ Naturkatastrophen beziehen. In Anlehnung an Definitionen der Vereinten Nationen werden Naturkatastrophen als „groß”︁ bezeichnet, wenn die Selbsthilfefähigkeit der betroffenen Regionen deutlich überschritten wird und überregionale oder internationale Hilfe erforderlich ist.
SEM and RBS characterization of a cobalt‐based conversion coating process on AA2024‐T3 and AA7075‐T6
Authors: Hughes A. E. , Gorman J. , Harvey T. G. , McCulloch D. , Toh S. K.
Published: November 2004

Samples of aluminium alloys AA2024‐T3 and AA7075‐T6 were treated with a chromate‐based deoxidizer, then conversion coated with a commercial cobalt‐based solution and finally sealed with a commercial vanadate‐based product. The alloy specimens were examined using scanning electron microscopy, transmission electron microscopy and Rutherford backscattering spectroscopy. The thickness of the cobalt‐based conversion coating increased rapidly up to 5 min of immersion but more slowly for longer times. Sealing resulted in penetration of vanadium through the oxide and a small increase in thickness due to the deposition of a thin sealing coating within the pores and on the external surface of the cobalt‐containing coating. Copyright © 2004 John Wiley & Sons, Ltd.
Characterization of cathodic film formed during reduction of chromic acid: role of sulphuric acid concentration
Authors: Van Parys Heidi , Maes Tom , Le Pen Christophe , Franquet Alexis , Hubin Annick
Published: November 2004

The surface composition of chromium, electrodeposited from a chromic acid solution with different amounts of sulphuric acid, has been investigated by means of Auger Electron Spectroscopy (AES) and X‐ray Photoelectron Spectroscopy (XPS). The quantity of sulphuric acid is a critical parameter in order to form metallic chromium instead of a non‐reducible chromium (III) oxide layer. The intermediate cathodic film formed on the electrode before the metallic chromium deposition has been investigated and XPS measurements have shown that a chromium oxide film is formed whatever the sulphuric acid concentration. However, in the presence of sufficient amounts of sulphate, this oxide is dissolved or the layer is broken down, giving rise to a free steel surface where the reduction of chromate ions into metallic chromium can take place. Copyright © 2004 John Wiley & Sons, Ltd.
Quantitative analysis of angle‐resolved XPS spectra recorded in parallel data acquisition mode
Authors: Vinodh M. S. , Jeurgens L. P. H.
Published: November 2004

The effects of anisotropy of the photoionization cross‐section and elastic scattering of photoelectrons in solids are investigated for angle‐resolved XPS spectra (ARXPS) recorded from α–Al2O3 substrate in parallel data acquisition mode. It is shown that for quantitative analysis of ARXPS spectra recorded in parallel data acquisition mode it is essential to account for the anisotropies of the photoionization cross‐sections of the detected photoelectrons for the concerned elements in the solid due to variation of the angle between the incident x‐rays and the detected photoelectrons. Neglecting the effect of elastic scattering only leads to minor errors in quantitative analysis of the ARXPS spectra. By adopting experimentally determined values for the relative sensitivity factors of the concerned photoelectrons in the solid as a function of the detection angle, cumbersome corrections for the effects of anisotropy of the photoionization cross‐section and elastic scattering can be avoided. Copyright © 2004 John Wiley & Sons, Ltd.
Adjusting for partially missing baseline measurements in randomized trials
Authors: White Ian R. , Thompson Simon G.
Published: November 2004

Adjustment for baseline variables in a randomized trial can increase power to detect a treatment effect. However, when baseline data are partly missing, analysis of complete cases is inefficient. We consider various possible improvements in the case of normally distributed baseline and outcome variables. Joint modelling of baseline and outcome is the most efficient method. Mean imputation is an excellent alternative, subject to three conditions. Firstly, if baseline and outcome are correlated more than about 0.6 then weighting should be used to allow for the greater information from complete cases. Secondly, imputation should be carried out in a deterministic way, using other baseline variables if possible, but not using randomized arm or outcome. Thirdly, if baselines are not missing completely at random, then a dummy variable for missingness should be included as a covariate (the missing indicator method). The methods are illustrated in a randomized trial in community psychiatry. Copyright © 2004 John Wiley & Sons, Ltd.
Estimating the growth rates of primary lung tumours from samples with missing measurements
Authors: Gorlova Olga , Peng Bo , Yankelevitz David , Henschke Claudia , Kimmel Marek
Published: November 2004

A method to estimate the population variability in tumour growth rate using incomplete data was developed. We assume exponential growth and lognormal distribution for the parameter of the growth curve. Estimates of growth rate obtained based on the cases with two measurements, one of which is obtained retrospectively, are biased towards lower growth rate. For the data sets where two measurements are available for some tumours and only one measurement for others (which means that no tumour was seen in retrospect for those cases), several approaches were developed that can eliminate or substantially reduce the bias. The relative error of the best estimates, as assessed by simulation, rarely exceeds 20 per cent. We found that the results of application of our estimation procedures to chest X‐ray screening data agree well with the expectations. Copyright © 2004 John Wiley & Sons, Ltd.
Impact of hourly wind power variations on the system operation in the Nordic countries
Authors: Holttinen Hannele
Published: November 2004

The variations of wind power production will increase the flexibility needed in the system when significant amounts of load are covered by wind power. When studying the incremental effects that varying wind power production imposes on the power system, it is important to study the system as a whole: only the net imbalances have to be balanced by the system. Large geographical spreading of wind power will reduce variability, increase predictability and decrease the occasions with near zero or peak output. The goal of this work was to estimate the increase in hourly load‐following reserve requirements based on real wind power production and synchronous hourly load data in the four Nordic countries. The result is an increasing effect on reserve requirements with increasing wind power penetration. At a 10% penetration level (wind power production of gross demand) this is estimated as 1·5%–4% of installed wind capacity, taking into account that load variations are more predictable than wind power variations. Copyright © 2004 John Wiley & Sons, Ltd.
JOHN LILBURNE AND THE CITIZENSHIP OF ‘FREE-BORN ENGLISHMEN’
Authors: FOXLEY RACHEL
Published: November 2004

John Lilburne's extensive writings were a major part of the pamphlet output of the Leveller movement. The apparent traditionalism of his language has obscured the extent to which he developed a radical line of thought. For Lilburne, all Englishmen are ‘free-born’; his radicalism lies in his assertion that this free status is to be seen as political status. The phrase ‘free-born Englishman’ comes to be a signifier of a uniform and inclusive citizenship, and the word ‘subject’ drops out of Lilburne's vocabulary. He reinterprets the language of the English legal tradition – following the lead of Sir Edward Coke – to make a collection of ‘liberties’, ‘franchises’, and ‘privileges’ into a uniform set of citizen entitlements. His writing suggests varying and sometimes incompatible grounds for this citizen status: historical arguments, and arguments depending on different notions of positive law, are employed alongside appeals to divine or natural law. However, Lilburne's attachment to the English legal tradition persists, and is an effective vehicle for the politicized vision of the English nation which he wants to convey.
An Agenda for Transnational Labor History
Authors: Hanagan Michael P.
Published: November 2004

Transnational labor history is attracting considerable interest today. Is it just another recondite buzzword or does transnational labor history offer a serious long-term program for discussion and research? This article defends the integrity of transnational labor history as a field, discusses the contributions it can make, and outlines some of the questions that it can most profitably address.
Cultures in Contact
Authors: Gabaccia Donna , Moch Leslie Page , Borges Marcelo J. , Iacovetta Franca , Hsu Madeline Y. , Manning Patrick , Lucassen Leo , Hoerder Dirk
Published: November 2004

In 2002, Dirk Hoerder published his magnum opus, Cultures in Contact: World Migrations in the Second Millennium (Durham, NC, 2002). In this book, Hoerder describes and analyses, with an unusual breadth of scope, the origins, causes, and extent of human migration around the globe from the eleventh century onward to the present day, paying particular attention to the impact migrations have had in the receiving countries and the cultural interactions they have triggered. At the 28th Annual Meeting of the American Social Science History Association, organized in November 2003 in Baltimore, Dirk Hoerder's book was the winner of the Allan Sharlin Memorial Award for the best book in social science history.

In this review symposium, seven migration scholars from differing national and cultural backgrounds give their comments on Hoerder's book, with a concluding response by Dirk Hoerder.
Dissipation of anomalous pressures in the subsurface
Authors: Muggeridge Ann , Abacioglu Yafes , England William , Smalley Craig
Published: November 2004

Zones of anomalous pressure, higher and lower than hydrostatic pressure, have been observed in many sedimentary basins around the world. These normally consist of groups of pressure compartments: volumes of higher‐permeability rock surrounded on all sides by lower‐permeability barriers. Knowledge of the timescales over which these abnormal pressures are maintained and the mechanisms by which they dissipate is critical for understanding how fluids, such as oil and gas, move in the subsurface. Existing analytic solutions investigate pressure dissipation through low‐permeability barriers on top of or underneath an isolated pressure compartment. There are no analytic solutions describing pressure dissipation through lateral barriers, such as faults, or investigating the impact of groups of pressure compartments on the rate of pressure dissipation. This paper presents simple analytic models to investigate pressure dissipation through barriers, such as faults, forming the sides of pressure compartments. The timescales are compared with a solution for pressure dissipation through barriers on top of and underneath the compartment. It also investigates analytically the rate of pressure dissipation from groups of pressure compartments. Lateral seal permeabilities of 10−19 m2 may delay pressure equilibration for millions of years provided the compartment has a sufficiently high fluid storage capacity. Factors contributing toward a high fluid storage capacity include a high fluid compressibility (as is the case in hydrocarbon reservoirs) and a high porosity. The grouping of abnormally pressured compartments into “megacompartment complexes” may delay pressure dissipation for hundreds of millions of years.
Observations of marine stratocumulus in SE Pacific during the PACS 2003 cruise
Authors: Kollias Pavlos , Fairall Christopher W. , Zuidema Paquita , Tomlinson Jason , Wick Gary A.
Published: November 2004

In November 2003, the NOAA Environmental Technology Laboratory (ETL) conducted measurements of Marine Boundary Layer (MBL) stratocumulus clouds, thermodynamic structure, surface fluxes and meteorology in the southeastern Pacific stratocumulus region. The observations were part of a field program to replace the WHOI Ocean Reference Station buoy at 20 S Latitude 85 W Longitude. During the cruise the MBL structure was characterized by a strong capping inversion, periods with well mixed conditions and marine stratus, clear sky periods and periods with moderate vertical gradients of potential temperature and mixing ratio that overlap with periods of small cloud fractional coverage, decoupled layers and low cloud base shallow cumuli clouds. The lifting condensation level (LCL) showed strong variability consistent with the variability of the MBL. Clouds with thickness more that 250 m had drizzle below the cloud base especially during nighttime. Large periods of clear skies were observed at the buoy location, especially just after the solar flux maximum. The aerosol size distribution measurements generally exhibited a bimodal structure. However, abrupt changes in the aerosol size distribution were also recorded, corresponding either with the presence of drizzle (and a depletion of the accumulation mode) or the presence of clear skies (and an increase in the Aitken mode). The stratocumulus observed during the 5‐day station at the buoy location revealed a far more complex picture from the one captured during the East Pacific Investigation of Climate (EPIC) cruise to this same location in 2001.
The effect of a global dust storm on simulations of the Martian water cycle
Authors: Böttger H. M. , Lewis S. R. , Read P. L. , Forget F.
Published: November 2004

Recent Mars Global Surveyor Thermal Emission Spectrometer (TES) observations have shown the effects of a global dust storm on the water cycle on Mars. Simulations using a Mars General Circulation Model were conducted to assess the influence of an arbitrary global dust storm on the modelled water cycle. Further, the effects of an adsorbing regolith during the dust storm were examined. Both with an active and a passive regolith the water cycle is substantially affected during the course of the dust storm, but returns to ambient conditions soon after the storm has abated. Differences between the simulations do exist, especially in the southern hemisphere during summer. When comparing the simulations with observations both the active and passive regolith simulations fail to fully replicate the general trends observed by TES. However, the actions of an adsorbing regolith appear to result in a water cycle more closely resembling the observations.
Modified sidereal filtering: Implications for high‐rate GPS positioning
Authors: Choi Kyuhong , Bilich Andria , Larson Kristine M. , Axelrad Penina
Published: November 2004

High‐rate (1‐Hz) Global Positioning System (GPS) data are beginning to be used for a variety of geophysical monitoring purposes, including seismology. Improving the precision of high‐rate GPS position estimates will increase the value of these 1‐Hz GPS monitoring systems. One technique that has been used to improve high‐rate GPS positioning takes advantage of the ground track repeat period of the satellites. This study investigates the GPS orbital repeat period and determines that it varies for each satellite and differs significantly from the generally assumed sidereal period. Orbit repeat periods are calculated and used to filter 1‐Hz GPS position estimates. Using the calculated orbit repeat period significantly reduces low frequency (0.001–0.04 Hz) errors in 1‐Hz GPS position estimates.
Weather systems occurring over Fort Simpson, Northwest Territories, Canada, during three seasons of 1998–1999: 1. Cloud features
Authors: Hudak D. , Currie B. , Stewart R. , Rodriguez P. , Burford J. , Bussières N. , Kochtubajda B.
Published: November 2004

An investigation of high‐latitude continental cloud systems was carried out in the interior of the Northwest Territories of Canada during three multiweek periods during the fall, winter, and spring of 1998–1999 as part of the Canadian Global Energy and Water Cycle Experiment (GEWEX) Enhanced Study. Radar data supplemented by satellite, upper air, and surface observations were used to determine the seasonal behavior of cloud macroscopic properties and compare these with similar observations elsewhere. Unique features included the prevalence of multilayered systems, the cold temperatures of low clouds, and a significant diurnal trend in cloud properties in the winter. A synoptic classification was developed and shown to be an important factor in explaining the variability of cloud properties. A consistent picture emerges of the upslope component and wind shear aloft contributing to the cloud structure in five synoptic classes. Vertically resolved cloud properties highlighted the importance of the ice process in these cloud systems. The cloud system reflectivity and temperature dependencies further supported the synoptic characterizations and highlighted the significance of using seasonally based relationships in automated cloud identification algorithms. The implication of the cloud system variability for radiation measurements was also shown. The radar reflectivity data, degraded to match CloudSat resolution and sensitivity, showed that cloud detection was reliable but that there was a positive bias with cloud thickness. Negative biases in cloud top retrievals based on advanced very high resolution radiometer data were also identified. The Global Environmental Multiscale model illustrated some degree of bias in the occurrence and vertical distribution of these cloud systems. Winter situations in general and midclouds situations in particular were the most poorly handled in both the satellite applications and the model simulations.
Weather systems occurring over Fort Simpson, Northwest Territories, Canada, during three seasons of 1998–1999: 2. Precipitation features
Authors: Stewart Ronald E. , Burford Jason E. , Hudak David R. , Currie Brian , Kochtubajda Bohdan , Rodriguez Peter , Liu Jinliang
Published: November 2004

Precipitation events were examined at Fort Simpson, Northwest Territories, Canada, during the autumn and winter of 1998 and during the spring of 1999 with a variety of observational tools, including a polarimetric radar. This location is characterized by a relatively small amount of precipitation (annual average of 450 mm), with approximately half being in the form of snow. During the observational periods, precipitation was produced within multilayered cloud systems with heights ranging up to 10 km, and instances of light snow were associated with either low (<2.5 km) or high (up to 10 km) clouds. Precipitation over the observational periods was typically produced in banded structures, was sometimes reduced because of subcloud evaporation or sublimation, and in the winter was often in the form of individual crystals. A state‐of‐the‐art weather forecasting model was often poor at simulating some of the critical features of the precipitation events, such as cloud top height and precipitation amount. In addition, it was shown that with the sensitive CloudSat radar, ∼17% of overpasses will be associated with the occurrence of detectable precipitation at Fort Simpson, but with the less sensitive Global Precipitation Measurement (GPM) radar, much of the precipitation will be undetected.
Carbon Balance in Leaves of Young Poplar Trees
Authors: Mayrhofer S. , Heizmann U. , Magel E. , Eiblmeier M. , Müller A. , Rennenberg H. , Hampp R. , Schnitzler J.‐P. , Kreuzwieser J.
Published: November 2004

Abstract: In the present study, important components of carbon metabolism of mature leaves of young poplar trees (Populus×canescens) were determined. Carbohydrate concentrations in leaves and xylem sap were quantified at five different times during the day and compared with photosynthetic gas exchange measurements (net assimilation, transpiration and rates of isoprene emission). Continuously measured xylem sap flow rates, with a time resolution of 15 min, were used to calculate diurnal balances of carbon metabolism of whole mature poplar leaves on different days. Loss of photosynthetically fixed carbon by isoprene emission and dark respiration amounted to 1 % and 20 %. The most abundant soluble carbohydrates in leaves and xylem sap were glucose, fructose and sucrose, with amounts of approx. 2 to 12 mmol m‐2 leaf area in leaves and about 0.2 to 15 mM in xylem sap. Clear diurnal patterns of carbohydrate concentration in xylem sap and leaves, however, were not observed. Calculations of the carbon transport rates in the xylem to the leaves were based on carbohydrate concentrations in xylem sap and xylem sap flow rates. This carbon delivery amounted to about 3 μmol C m‐2 s‐1 during the day and approx. 1 μmol C m‐2 s‐1 at night. The data demonstrated that between 9 and 28 % of total carbon delivered to poplar leaves during 24 h resulted from xylem transport and, hence, provide a strong indication for a significant rate of carbon cycling within young trees.
Blue Light Delays Commitment to Cell Division in Chlamydomonas reinhardtii
Authors: Oldenhof H. , Zachleder V. , van den Ende H.
Published: November 2004

Abstract: In this study, we describe the effect of red and blue light on the timing of commitment to cell division in Chlamydomonas reinhardtii. The time point and cell size after which cells can complete their cell cycle with one division round were determined for cultures that were exposed to various red and blue light periods. We show that the commitment point of cells grown in blue light is shifted to a later time point and a larger cell size, when compared with cells grown in red light. This shift was reduced when cultures were exposed to shorter blue light periods. Furthermore, this shift occurred only when exposure to blue light started before the cells attained a particular size. We conclude that the critical cell size for cell division, which is the cell size at which commitment to cell division is attained, is dependent on spectral composition.
Harmonic analysis of linear fields on the nilgeometric cosmological model
Authors: Tanimoto Masayuki
Published: November 2004

To analyze linear field equations on a locally homogeneous space–time by means of separation of variables, it is necessary to set up appropriate harmonics according to its symmetry group. In this paper, the harmonics are presented for a spatially compactified Bianchi II cosmological model—the nilgeometric model. Based on the group structure of the Bianchi II group (also known as the Heisenberg group) and the compactified spatial topology, the irreducible differential regular representations and the multiplicity of each irreducible representation, as well as the explicit form of the harmonics are all completely determined. They are also extended to vector harmonics. It is demonstrated that the Klein–Gordon and Maxwell equations actually reduce to systems of ODEs, with an asymptotic solution for a special case.
Crystal bases and generalized Lascoux–Leclerc–Thibon (LLT) algorithm for the quantum affine algebra Uq(Cn(1))
Authors: Kim Jeong-Ah , Shin Dong-Uy
Published: November 2004

In this paper, we give a realization of crystal bases of the fundamental representations over Uq(Cn(1)) in terms of Young diagrams k introduced by Premat. Further, we give a generalized Lascoux–Leclerc–Thibon algorithm for computing the global bases.
On the form factor for the unitary group
Authors: Esposti Mirko Degli , Knauf Andreas
Published: November 2004

We study the combinatorics of the contributions to the form factor of the group U(N) in the large N limit. This relates to questions about semiclassical contributions to the form factor of quantum systems described by the unitary ensemble.
Some considerations for a method that simultaneously measures the temperature and emissivity of a metal in a high temperature furnace
Authors: Iuchi Tohru , Furukawa Tohru
Published: November 2004

This article describes some considerations for designing a practical radiation thermometry system for a glossy metal moving through a high temperature furnace, such as a continuous annealing furnace. In order to accomplish this task, two problems must be solved. The emissivity compensation of an object must be calculated and the furnace’s background radiation noise must be eliminated. The authors have proposed a method that uses the radiance’s polarized directional properties to simultaneously measure the emissivity and temperature to solve the first problem and a technique using a pseudo-blackbody installed in the furnace to solve the second problem. During heating, there is a one-to-one correspondence between the emissivity and the ratio of p- and s-polarized radiances for metals. This characteristic has successfully led to the development of a method for simultaneously measuring the emissivity and temperature of metals regardless of a potential large change in emissivity. Introducing a pseudo-blackbody radiator into a furnace removes the background radiation noise. Moreover, the blackbody radiator supplies a constant reference radiance. This reference plays an important role in maintaining the principle of emissivity-compensated radiation thermometry inside the furnace. Experimental results have simultaneously measured the emissivity and temperature of stainless steel at 1300 K with errors of 12% and 0.96%, respectively. These values were attained even though the s-polarized emissivities change from 0.25 to 0.75 at a wavelength of 0.9 μm. These errors can be achieved by designing the apparatus to have a solid angle, the aperture of the pseudo-blackbody subtended by a measuring point of the specimen, of more than 0.02π steradians. The accuracy of this method is heavily dependent upon the specimen’s surface roughness. The maximum surface roughness that allows for the successful utilization of this method is Ra=0.12 μm.
Multichannel optical diagnostic system for field-reversed configuration plasmas
Authors: Takahashi Tsutomu , Gota Hiroshi , Fujino Toshiyuki , Okada Masanori , Asai Tomohiko , Fujimoto Kayoko , Ohkuma Yasunori , Nogi Yasuyuki
Published: November 2004

A constructed diagnostic system consisting of a 60-channel set of optical detectors with flexible viewing configurations is realized to investigate three-dimensional magnetohydrodynamic (MHD) motions and the internal structure of a field-reversed configuration (FRC) plasma. The system can detect radiation from the plasma in the wavelength range of 420–820 nm. Optical filters are used to select the wavelength ranges required in the experiment. The sensitivities of all the optical detectors are calibrated using radiation from the FRC plasma at a quiescent phase. Radiation profiles measured by orthogonal viewing configuration of the detectors are shown at three toroidal cross sections. From these profiles, the time evolution of the three-dimensional MHD motion of the plasma is depicted. The radiation profile measured by a one-dimensional viewing configuration yields not only an electron density profile inside the separatrix but also the width of an edge-layer plasma. A bright halo around the edge-layer plasma is observed using a Balmer-α line filter. The orthogonal viewing configuration can also be used to analyze the internal structure of the FRC. The deviated position of the major axis is estimated from the comparison between the measured radiation profiles and the nonconcentric density profile based on the rigid rotor profile model.
Heat Shock Protein‐27 Is Upregulated in the Temporal Cortex of Patients with Epilepsy
Authors: Bidmon Hans‐J , Görg Boris , Palomero‐Gallagher Nicola , Behne Friedrich , Lahl Rainer , Pannek Hans W. , Speckmann Erwin‐J , Zilles Karl
Published: November 2004

Summary:  Purpose: Heat shock protein‐27 (HSP‐27) belongs to the group of small heat shock proteins that become induced in response to various pathologic conditions. HSP‐27 has been shown to protect cells and subcellular structures, particularly mitochondria, and serves as a carrier for estradiol. It is a reliable marker for tissues affected by oxidative stress. Oxidative stress and related cellular defence mechanisms are currently thought to play a major role during experimentally induced epileptic neuropathology. We addressed the question whether HSP‐27 becomes induced in the neocortex resected from patients with pharmacoresistant epilepsy.

Methods: Human epileptic temporal neocortex was obtained during neurosurgery, and control tissue was obtained at autopsy from subjects without known neurologic diseases. The tissues were either frozen for Western blot analysis or fixed in Zamboni's fixative for the topographic detection of HSP‐27 at the cellular level by means of immunohistochemistry.

Results: HSP‐27 was highly expressed in all epilepsy specimens and in the cortex of a patient who died in the final stage of multiple sclerosis (positive control), whereas only low amounts of HSP‐27 were detectable in control brains. In epilepsy patients, HSP‐27 was present in astrocytes and in the walls of blood vessels. The intracortical distribution patterns varied strongly among the epilepsy specimens.

Conclusions: These results demonstrate that HSP‐27 becomes induced in response to epileptic pathology. Although the functional aspects of HSP‐27 induction during human epilepsy have yet to be elucidated, it can be concluded that HSP‐27 is a marker for cortical regions in which a stress response has been caused by seizures.
Progestins in the Hippocampus of Female Rats Have Antiseizure Effects in a Pentylenetetrazole Seizure Model
Authors: Rhodes Madeline E. , Frye Cheryl A.
Published: November 2004

Summary:  Purpose: Progestins can have profound effects on seizure processes. However, the effects and mechanisms of progestins to modulate seizures have not been systematically investigated. The present studies were designed to characterize the effects of progestins to modulate pentylenetetrazole (PTZ)‐induced seizures in female rats.

Methods: In Experiment 1, ictal activity and plasma and hippocampal progesterone (P) and 5α‐pregnan‐3α‐ol‐20‐one (3α,5α‐THP) levels of proestrous rats were compared with those of diestrous and ovariectomized (ovx) rats. Experiments 2 and 3 examined effects of ovx and replacement with vehicle, P, or 3α,5α‐THP, systemically (Experiment 2) or to the hippocampus (Experiment 3) on seizures and plasma and hippocampal P and 3α,5α‐THP concentrations.

Results: Proestrous rats had reduced ictal activity and increased levels of P and 3α,5α‐THP in plasma and hippocampus compared with diestrous or ovx rats (Experiment 1). Rats administered systemic P or 3α,5α‐THP had significantly reduced ictal activity and increased plasma and hippocampal P and 3α,5α‐THP levels compared with vehicle‐administered rats (Experiment 2). Administration of P or 3α,5α‐THP to the hippocampus of ovx rats significantly reduced seizure activity and increased hippocampal, but not plasma, levels of P and 3α,5α‐THP compared with vehicle administration (Experiment 3).

Conclusions: Together, these data suggest that P can have antiseizure effects, and these effects may be due in part to actions of its metabolite, 3α,5α‐THP, in the hippocampus.