bluuebunny/crossref_metadata_2025 huggingface dataset:
Model‐based evaluation of methods to determine C:N and N:P regeneration ratios from dissolved nutrients
Authors: Schneider Birgit , Karstensen Johannes , Oschlies Andreas , Schlitzer Reiner
Published: April 2005

Four indirect methods to determine carbon and nutrient regeneration ratios in the ocean are applied to results from a physical‐biogeochemical model with prescribed element ratios for organic matter (de‐)composition. The aim is to test whether these methods are suitable to reproduce Corg:N:P element ratios of organic matter remineralization, which in contrast to the real ocean are exactly known in the model framework. The model experiment is carried out using the classical C:N:P Redfield ratio of 106:16:1 for production and decomposition of organic material under preindustrial atmospheric pCO2. Two methods rely on predefined end member values, while the others do not. The first method is a simple linear regression of two parameters, neglecting mixing effects, and yields remineralization signals biased by isopycnal tracer gradients induced by contributions of different water masses. The second method is based on multiple linear regression of three parameters, includes mixing of three, but not‐prescribed end members. It can, in part, reproduce the prescribed remineralization ratios. However, considerable bias appears as a result of water mass mixing. The third method considers isopycnal mixing of three prescribed end member water masses by using temperature/salinity as conservative tracers on the two density surfaces σΘ = 26.8 and σΘ = 27.2. On the basis of a mixing triangle approach, the method is able to reproduce the regeneration rates best in the low latitudes, where the integrated signal of remineralization is high. The fourth method uses the full set of available parameters to derive mixing fractions and remineralization and is applied to the density range from σΘ = 26.8 to σΘ = 27.2, yielding the best reproduction of prescribed remineralization ratios. As expected, results from the last two methods are sensitive to the choice of end member concentrations. In general, best agreement between modeled and reconstructed ratios is found between 20°N and 20°S and deviations occur toward the outcrop regions, which we account to the low amount of remineralized material together with uncertainties in prescribed end member values. Our investigation shows how apparent variability of remineralization ratios can be generated through methodological shortcomings only.
Effect of scaling and regression on reconstructed temperature amplitude for the past millennium
Authors: Esper Jan , Frank David C. , Wilson Robert J. S. , Briffa Keith R.
Published: April 2005

Examination of large‐scale millennial‐long temperature reconstructions reveals a wide range of datasets and methods used for calibration. Proxy time series are commonly calibrated against overlapping instrumental records, representing different seasons, Northern Hemisphere latitudinal bands, and including or excluding sea surface temperature data. Methodological differences include, using scaling or regression, the calibration time period, and smoothing data before calibration. We find that these various approaches alone can result in differences in the reconstructed temperature amplitude of about 0.5°C. This magnitude is equivalent to the mean annual temperature change for the Northern Hemisphere reported in the last IPCC report for the 1000–1998 period. A more precise assessment of absolute reconstructed temperature amplitudes is necessary to help quantify the relative influences of forcing mechanisms in climate models.
Determination of primary electron spectra from incoherent scatter radar measurements of the auroral E region
Authors: Semeter Joshua , Kamalabadi Farzad
Published: April 2005

A technique is presented for inverting incoherent scatter radar (ISR) measurements of the auroral ionosphere to determine the incident electron energy spectrum. A linear model is constructed relating electron differential number flux to the volume production rate of ions, the latter derived from measured electron density profiles using a continuity equation. The forward model is inverted using the maximum entropy method (MEM). This implementation of ISR inversion was found to be remarkably robust to the principal sources of model and measurement uncertainty. The procedure was applied to high‐resolution measurements (1.2 s × 1 km) by the Sondrestrom ISR recorded during an auroral surge. Analysis of bulk plasma properties in the recovered spectra suggested that the relationship between the characteristic energy and the net number flux was highly nonlinear during the onset of the auroral surge, an observation that can now be evaluated statistically. This perspective on the temporal behavior of the auroral acceleration region cannot be accessed through spaceborne measurements; ISR inversion thus constitutes a critical tool for addressing time‐dependent coupling of the magnetosphere and ionosphere.
MJO‐related oceanic Kelvin waves and the ENSO cycle: A study with the NCEP Global Ocean Data Assimilation System
Authors: Seo Kyong‐Hwan , Xue Yan
Published: April 2005

The surface wind anomalies associated with the Madden‐Julian oscillation (MJO) appear to play a critical role during the onset and termination phases of ENSO. The characteristics of the MJO‐related oceanic Kelvin waves have not been systematically studied due to a lack of ocean reanalysis that resolves intraseasonal variability. This study uses the operational ocean reanalysis for the period 1982–2003 produced by the state‐of‐art global ocean data assimilation system at NCEP to explore the relationship between SST anomalies of ENSO and MJO‐related oceanic Kelvin waves. The first four extended empirical orthogonal functions of the depth of 20°C isotherm are used to represent the dominant oceanic Kelvin waves. The wave activity is measured by seasonal variance of oceanic Kelvin waves (SVKW) at 130°W. SVKW peaks are associated with the onset stage of warm ENSO events since they occur during the transition period and tend to produce positive tendency in NINO3.4 and heat content, and lead mature phases by 5–11 months. MJO‐related oceanic Kelvin wave activity is also shown to impact the growth and termination of warm events. The consistent relationships do not occur in cold events. A real time monitoring tool using SVKW index is proposed to support the official ENSO forecast at NCEP.
A population genetic study of the endangered plant species Limonium dufourii (Plumbaginaceae) based on amplified fragment length polymorphism (AFLP)
Authors: Palacios CARMEN , Kresovich STEPHEN , González‐Candelas FERNANDO
Published: April 2005

Limonium dufourii (Plumbaginaceae) is a triploid species with obligate apomictic reproduction and is endemic to the East Mediterranean coast of Spain, where it is present in only six populations, most of which have a very low number of individuals. Genetic variation and population structure in this species was studied using amplified fragment length polymorphisms (AFLPs) as markers, using the same individuals as in a previous study with random amplified polymorphic DNA (RAPD). Three different primers provided 252 bands of which 51 were polymorphic among the 152 individuals analysed. Those polymorphic bands were able to define 65 different phenotypes, of which all but two were present in only one population. The comparative analyses of data from AFLPs with those from RAPDs show a high degree of concordance. Additionally, and given the nature of these markers, we propose the estimation of nucleotide divergences from AFLP patterns. Relationships among the different AFLP patterns and the estimates of population genetic parameters obtained with this evolutionary distance are in good agreement with previous results. These analyses show that substantial genetic variability and differentiation exist within and among populations of L. dufourii. Their higher reproducibility and the possibility of obtaining estimates of nucleotide divergence make AFLPs a much better DNA fingerprinting technique.
Selection and evaluation of root nodule bacteria for Dorycnium spp.
Authors: Davies S. R. , Howieson J. G. , Yates R. J. , Lane P. A.
Published: April 2005

Dorycnium spp. are perennial legumes that have the ability to produce a source of forage in low fertility soils under low rainfall conditions. The inoculation of Dorycnium spp. is currently with the commercial Lotus corniculatus inoculant SU343, which until now had not been trialed against a range of alternative inoculants for Dorycnium spp. A glasshouse trial in sterile sand culture was conducted with 3 species of Dorycnium spp. along with 6 important pasture legumes to evaluate nitrogen-fixing performance, and host and rhizobia interactions. Several inoculants were selected from this trial to undergo evaluation under Tasmanian field conditions. The dry matter production of Dorycnium spp. in the glasshouse and field indicated that SU343 is a suitable inoculant for this genus. A Tasmanian isolate (WSM2338) was identified as a complimentary strain for the inoculation of Dorycnium spp., however, negative interactions with important pasture legumes require further investigation.
Performance of temperate and subtropical forage legumes when over-seeding native pastures in the basaltic region of Uruguay
Authors: Real D. , Labandera C. A. , Howieson J. G.
Published: April 2005

In 1997, an integrated plant breeding program was initiated at the National Agricultural Research Institute (INIA) Uruguay, to develop forage legumes and root nodule bacteria which were able to be productive in co-existence with the native (grass-dominant) vegetation when grazed by cattle and sheep. The program was conducted in parallel with rhizobial strain selection by the Rhizobium–Biological Nitrogen Fixation Unit of the Soil Microbiology Department of the Ministry of Livestock, Agriculture and Fisheries of Uruguay and the Centre for Rhizobium Studies (CRS), Murdoch University, Western Australia.
Between 1998 and 2000, 326 temperate and subtropical forage legume species originating from 38 ex-situ seed collections were evaluated in 3 plantings on: red lithosol, black lithosol and vertisol soils at Glencoe Research Station in Uruguay. Row–column field designs were used. Forage production at the end of the second year of evaluation was used as the key selection parameter for the introduced legumes because their success required persistence in the pasture either vegetatively or by natural reseeding. This study identified a set of promising legumes and strains of Rhizobium that are now available for further study and breeding in Uruguay as well as other countries with a similar climate. The methodology developed in this study may be applicable to forage selection programs in which competition between annual and perennial species is expected to influence outcomes.
Improving the survival of rhizobia on Desmanthus and Stylosanthes seed at high temperature
Authors: McInnes A. , Date R. A.
Published: April 2005

In response to observed inoculation failures in the tropical forage legumes Desmanthus spp. and Stylosanthes seabrana, research was initiated to improve the survival of rhizobia on seed at high temperature. We compared the survival of rhizobia in freeze-dried and conventional peat inoculants in the laboratory at 30–50°C and 5–8% relative humidity. Higher numbers of rhizobia [>106 colony forming units (cfu)/seed] were counted on seed inoculated with freeze-dried rhizobia compared with seed inoculated with peat (≤104) in all treatments at all sampling times (0, 2, 7, 14 and 21 days after inoculation). Increasing the incubation temperature to 70°C significantly (P<0.05) reduced the number of freeze-dried rhizobia surviving on seed, but rhizobia were detectable on Desmanthus seed 1, 2 and 7 days after inoculation and on Stylosanthes seed 1 and 2 days after inoculation. Freeze-dried rhizobia stored over silica gel in the laboratory for 325–349 days lost 3.5–4.5 log10 cfu/g. Freeze-dried rhizobia inoculated on seed and stored in a farm shed from April to July lost 0.6–0.8 log10 cfu/seed.month. Survival of rhizobia in peat and freeze-dried inoculants on seed over 1–4 weeks in a glasshouse without air conditioning (18–51°C) was poor (0–1.2 log10 cfu/seed at all sampling times), and was attributed to exposure to a combination of high temperature and ambient relative humidity. Laboratory studies confirmed that increasing relative humidity from 5–8 to 31–63% reduced the survival of rhizobia in freeze-dried inoculants on seed, particularly at 50°C. Further work is required to improve the survival of freeze-dried inoculants at a relative humidity greater than 5–8% and under long-term storage. Optimisation of this technology has the potential to increase inoculation success for all legumes sown at high temperature in Australia. Freeze-dried inoculant technology may also have an application in seed preinoculation.
The interactions of Rhizobium leguminosarum biovar trifolii in nodulation of annual and perennial Trifolium spp. from diverse centres of origin
Authors: Howieson J. G. , Yates R. J. , O'Hara G. W. , Ryder M. , Real D.
Published: April 2005

The release of effective inocula for new perennial clovers into cropping zones where subterranean clover is important might compromise N2 fixation by this valuable annual clover if symbiosis between the new inoculants and subterranean clover is not optimal. To assist our understanding of the interactions between clovers and their microsymbionts, rhizobial strains and clovers from South and equatorial Africa, North and South America, and the Euro–Mediterranean regions were tested. Glasshouse-based studies of the cross-inoculation characteristics of 38 strains of Rhizobium leguminosarum bv. trifolii associated with 38 genotypes of annual and perennial Trifolium spp. from these world centres of diversity were undertaken. Less than 7.5% of the perennial clover symbioses were effective whereas 40% of associations were effective for many of the annual clover species of Euro–Mediterranean origin. There was substantial specificity within the African clovers for effective nodulation. Rhizobial strains from the South American perennial T. polymorphum or from the African clovers were unable to nodulate subterranean clover effectively. Also, 7 of the 17 strains from these regions were unable to form nodules with the less promiscuous Mediterranean annual clovers, T. glanduliferum and T. isthmocarpum. Fifty-three of about 400 cross-inoculation treatments examined, which included annual and perennial clovers, were incapable of forming nodules, while only 65 formed effective nodules. There are 2 barriers to effective nodulation: a ‘geographic’ barrier representing the broad centres of clover diversity, across which few host-strain combinations were effective; and, within each region, a significant ‘phenological’ barrier between annual and perennial species. Clovers and their rhizobia from within the Euro–Mediterranean region of diversity were more able to cross the phenological barrier than genotypes from the other regions. It appears that only the relatively promiscuous clovers, whether annual or perennial, have been commercialised to date. The data indicate that, for perennial clovers, it will be a substantial challenge to develop inocula that do not adversely affect N2 fixation by subterranean clover and other annual clovers available commercially, especially if the perennial clovers were originally from Africa or America. Some future strategies for development of inoculants for clovers are proposed.
Embryo transfer in the dromedary camel (Camelus dromedarius) using asynchronous, meclofenamic acid-treated recipients
Authors: Skidmore Julian A. , Billah M.
Published: April 2005

A total of 40 (Day 7) embryos were recovered from the uteri of 10 superovulated camels. Recipient camels (n = 30) were prepared by injection with 20 μg of the gonadotrophin-releasing hormone analogue buserelin (i.v.) to induce ovulation and then treatment with 1 g meclofenamic acid (a prostaglandin synthetase inhibitor), orally, once on Day 7 and twice daily on Days 8 and 9 after ovulation and thereafter at a dose of 1 g day−1 until 8 days after embryo transfer. Embryos were transferred into recipients on Day 8 (n = 10), Day 10 (n = 10) or Day 12 (n = 10) after ovulation and another 10 embryos were transferred into untreated recipients on Day 8 after ovulation as controls. In addition, serum samples from all recipient camels were recovered daily throughout the period of meclofenamic acid administration and for a further 7 days after treatment had ceased and were assayed for progesterone concentrations. Results showed that whereas only one of 10 of the control group of recipients (10%) was diagnosed pregnant, a total of eight of 10 Day 8 (80%), six of 10 Day 10 (60%) and seven of 10 Day 12 (70%) recipients were diagnosed pregnant by ultrasonography 12 days after the embryo had been transferred. Subsequently, however, four pregnancies were lost when the conceptus was aged between 22 and 60 days, but this is not considered above the early fetal mortality rate expected in camels after natural mating or after transferring camel embryos to untreated recipients. Serum progesterone concentrations remained elevated, above 2 ng mL−1, throughout the period of meclofenamic acid administration in all recipient camels; thereafter, concentrations remained above 2 ng mL−1 in pregnant animals, whereas in non-pregnant camels concentrations had declined to baseline values (<1 ng mL−1) within 3 days of the end of the treatment period. In conclusion, treatment of recipient camels with meclofenamic acid reduced the need for tightly timed synchrony between donor and recipient because pregnancies were established in recipients that had ovulated as much as 5 days ahead of the donor.
Follicular expression of a human β-cell leukaemia/lymphoma-2 (Bcl-2) transgene does not decrease atresia or increase ovulation rate in swine
Authors: Guthrie H. D. , Wall R. J. , Pursel V. G. , Foster-Frey J. A. , Donovan D. M. , Dawson H. D. , Welch G. R. , Garrett W. G.
Published: April 2005

Transgenic (TG) gilts carrying a human Bcl-2 cDNA transgene driven by mouse inhibin-α subunit promoter were produced and evaluated to determine if ectopic expression of Bcl-2 in the ovaries would decrease the frequency of atresia in antral follicles and increase ovulation rate. Immunohistochemical analysis showed that the Bcl-2 transgene protein was expressed in granulosa and theca cells, in 86% of healthy and 54% of atretic follicles analysed in TG prepubertal and Day 50 pregnant gilts combined (n = 24). In contrast, Bcl-2 transgene protein was expressed in only 1.4% of healthy and 0% of atretic follicles in non-TG littermates (n = 13). Real-time reverse transcription–polymerase chain reaction analysis confirmed that human Bcl-2 was expressed in follicles of TG gilts. The atresia rate for the TG and non-TG groups did not differ (P > 0.05) for prepubertal (45 v. 59%) and Day 50 pregnant gilts (53 v. 52%) respectively. The mean ± s.e.m. ovulation rate did not differ (P > 0.5) between TG (15.9 ± 0.8, n = 12) and non-TG (16.4 ± 0.6, n = 7) Day 50 pregnant gilts. The molecular basis of the failure of ectopic Bcl-2 expression to increase the ratio of healthy to atretic follicles is unknown, but it is possible that the activity of the mitochondrial-dependent cell death pathway was not neutralized by ectopic expression of human Bcl-2 or that other cell death pathways compensated for the decreased mitochondrial-dependent cell death.
Meat and milk compositions of bovine clones
Authors: Tian X. Cindy , Kubota Chikara , Sakashita Kunihito , Izaike Yoshiaki , Okano Ryoichi , Tabara Norio , Curchoe Carol , Jacob Lavina , Zhang Yuqin , Smith Sadie , Bormann Charles , Xu Jie , Sato Masumi , Andrew Sheila , Yang Xiangzhong
Published: April 2005

The technology is now available for commercial cloning of farm animals for food production, but is the food safe for consumers? Here, we provide data on >100 parameters that compare the composition of meat and milk from beef and dairy cattle derived from cloning to those of genetic- and breed-matched control animals from conventional reproduction. The cloned animals and the comparators were managed under the same conditions and received the same diet. The composition of the meat and milk from the clones were largely not statistically different from those of matched comparators, and all parameters examined were within the normal industry standards or previously reported values. The data generated from our match-controlled experiments provide science-based information desired by regulatory agencies to address public concerns about the safety of meat and milk from somatic animal clones.
Dynein Light Chain 1 Regulates Dynamin-mediated F-Actin Assembly during Sperm Individualization inDrosophila
Authors: Ghosh-Roy Anindya , Desai Bela S. , Ray Krishanu
Published: April 2005

Toward the end of spermiogenesis, spermatid nuclei are compacted and the clonally related spermatids individualize to become mature and active sperm. Studies in Drosophila showed that caudal end-directed movement of a microfilament-rich structure, called investment cone, expels the cytoplasmic contents of individual spermatids. F-actin dynamics plays an important role in this process. Here we report that the dynein light chain 1 (DLC1) of Drosophila is involved in two separate cellular processes during sperm individualization. It is enriched around spermatid nuclei during postelongation stages and plays an important role in the dynein-dynactin–dependent rostral retention of the nuclei during this period. In addition, DDLC1 colocalizes with dynamin along investment cones and regulates F-actin assembly at this organelle by retaining dynamin along the cones. Interestingly, we found that this process does not require the other subunits of cytoplasmic dynein-dynactin complex. Altogether, these observations suggest that DLC1 could independently regulate multiple cellular functions and established a novel role of this protein in F-actin assembly in Drosophila.
Functional interaction of Oct transcription factors with the family of repeats in Epstein–Barr virus oriP
Authors: Almqvist J. , Zou J. , Linderson Y. , Borestrom C. , Altiok E. , Zetterberg H. , Rymo L. , Pettersson S. , Ernberg I.
Published: April 2005

The family of repeats (FR) is a major upstream enhancer of the Epstein–Barr virus (EBV) latent C promoter (Cp) that controls transcription of six different latent nuclear proteins following interaction with the EBV nuclear protein EBNA1. Here, it was shown that Cp could also be activated by octamer-binding factor (Oct) proteins. Physical binding to the FR by the cellular transcription factors Oct-1 and Oct-2 was demonstrated by using an electrophoretic mobility-shift assay. Furthermore, Oct-1 in combination with co-regulator Bob.1, or Oct-2 alone, could drive transcription of a heterologous thymidine kinase promoter linked to the FR in both B cells and epithelial cells. Cp controlled by the FR was also activated by binding of Oct-2 to the FR. This may have direct implications for B cell-specific regulation of Cp.
Correlation between interferon sensitivity of reovirus isolates and ability to discriminate between normal and Ras-transformed cells
Authors: Rudd Penny , Lemay Guy
Published: April 2005

Mammalian reoviruses exhibit a propensity to replicate in transformed cells. It is currently believed that the interferon-inducible RNA-dependent protein kinase (PKR), an intracellular host-cell resistance factor that is inhibited by an activatedRas-dependent pathway in transformed cells, is responsible for this discrimination. In the present study, reovirus isolates differing in their sensitivity to interferon were obtained by chemical mutagenesis, and examined for their replicative properties in parental andRas-transformed mouse NIH-3T3 cells. It was observed that most isolates can bypass resistance mechanisms of parental cells at high m.o.i., and that there is a correlation between the ability to discriminate between transformed and parental cells, and interferon sensitivity. Most interestingly, an interferon-hypersensitive mutant virus was more dependent onRasactivation than any other viral isolate. Altogether, this suggests that optimal reovirus isolates could be selected to attack tumour cells depending on the nature of the alterations in interferon-inducible pathways found in these cells.
Differential transcriptional activity of plant-pathogenic begomoviruses in their whitefly vector (Bemisia tabaci, Gennadius: Hemiptera Aleyrodidae)
Authors: Sinisterra Xiomara H. , McKenzie C. L. , Hunter Wayne B. , Powell Charles A. , Shatters Robert G.
Published: April 2005

Plant-pathogenic begomoviruses have a complex association with their whitefly vector and aspects concerning virus genetic activity (genome replication and gene transcription) within the insect remain highly controversial. Virus transcript abundance was assessed by quantifying selected gene transcripts of Tomato mottle virus (ToMoV, a New World bipartite begomovirus) and Tomato yellow leaf curl virus (TYLCV, an Old World monopartite begomovirus) in whiteflies (Bemisia tabaci biotype B) after feeding on virus-infected tomato plants and after subsequent transfer to cotton, a plant that is immune to the selected begomoviruses. Real-time RT-PCR was performed using specific primers for three ToMoV genes (AV1, BC1 and BV1) and three TYLCV genes (V1, V2 and C3). The ToMoV gene transcripts rapidly became undetectable in whiteflies following transfer from tomato to cotton, probably because degradation was not accompanied by new synthesis. On the other hand, TYLCV transcripts increased after transfer of whiteflies to cotton, indicating active TYLCV transcription. Interestingly, the difference observed in ToMoV and TYLCV transcripts in the vector parallel observations on the different biological effects of these viruses on whiteflies, i.e. TYLCV, but not ToMoV, reduces whitefly fitness.
Analysis of porcine reproductive and respiratory syndrome virus attachment and internalization: distinctive roles for heparan sulphate and sialoadhesin
Authors: Delputte P. L. , Costers S. , Nauwynck H. J.
Published: April 2005

Heparan sulphate and sialoadhesin were previously identified on porcine macrophages as receptors for porcine reproductive and respiratory syndrome virus (PRRSV). In this study, the exact role and cooperation of heparan sulphate and sialoadhesin during PRRSV attachment and internalization was analysed. It was observed that both heparan sulphate and sialoadhesin mediate PRRSV attachment and that only these two receptors are involved in attachment. Analysis of attachment kinetics of PRRSV to macrophages revealed that early attachment is mediated mainly via an interaction with heparan sulphate, followed by a gradual increase in interaction with sialoadhesin. By using wild-type CHO and CHO deficient in heparan sulphate expression, it was shown that heparan sulphate alone is sufficient to mediate PRRSV attachment, but not entry, and that heparan sulphate is not necessary for sialoadhesin to function as a PRRSV internalization receptor, but enhances the interaction of the virus with sialoadhesin.
Spodoptera frugiperda resistance to oral infection by Autographa californica multiple nucleopolyhedrovirus linked to aberrant occlusion-derived virus binding in the midgut
Authors: Haas-Stapleton Eric J. , Washburn Jan O. , Volkman Loy E.
Published: April 2005

Spodoptera frugiperda larvae are highly resistant to oral infection by Autographa californica multiple nucleopolyhedrovirus (AcMNPV) (LD50, ∼9200 occlusions), but extremely susceptible to budded virus within the haemocoel (LD50, <1 p.f.u.). The inability of AcMNPV occlusion-derived virus (ODV) to establish primary infections readily within midgut cells accounts for a major proportion of oral resistance. To determine whether inappropriate binding of AcMNPV ODV to S. frugiperda midgut cells contributes to lack of oral infectivity, the binding and fusion properties of AcMNPV ODV were compared with those of the ODV of a new isolate of Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV) obtained from a field-collected larva (oral LD50, 12 occlusions). By using a fluorescence-dequenching assay conducted in vivo, it was found that AcMNPV ODV bound to the midgut epithelia of S. frugiperda larvae at ∼15 % of the level of SfMNPV ODV, but that, once bound, the efficiencies of fusion for the two ODVs were similar: 60 % for AcMNPV and 53 % for SfMNPV. Whilst the difference in binding efficiencies was significant, it could not account entirely for the observed differences in infectivity. Competition experiments, however, revealed that, in S. frugiperda larvae, SfMNPV ODV bound to a midgut cell receptor that was not bound by AcMNPV ODV, indicating that ODV interaction with a specific receptor(s) was necessary for productive infection of midgut columnar epithelial cells. Fusion in the absence of this ligand–receptor interaction did not result in productive infections.
Effects of the PKC inhibitor PD 406976 on cell cycle progression, proliferation, PKC isozymes and apoptosis in glioma and SVG‐transformed glial cells
Authors: Russell C. , Acevedo‐Duncan M.
Published: April 2005

Abstract.  It is well established that protein kinase C (PKC) isozymes are involved in the proliferation of glioma cells. However, reports differ on which PKC isozymes are responsible for glioma proliferation. As a means to further elucidate this, the objectives of our research were to determine how inhibition of PKC‐α, PKC‐β and PKCµ with PD 406976 regulates the cell cycle, cell proliferation and PKC during glioma growth and development. To establish the cell cycle effects of PD 406976 on brain cells (SVG, U‐138MG and U‐373MG glioma cells), specimens were treated with either dimethylsulfoxide (DMSO; control) or PD 406976 (2 µm). Results from flow cytometry demonstrated that PD 406976 delayed the entry DNA synthesis phase in SVG cells and delayed the number of cells entering and exiting the DNA synthesis phase in both U‐138MG and U‐373MG cells, indicating that PD 406976 may inhibit G1/S and S phase progression. Assessment of cell viability demonstrated a cytostatic effect of PD 406976 on SVG, U‐138MG and U‐373MG glioma cell proliferation. The PD 406976‐induced decreased proliferation was sustained at 48–96 h. A PKC activity assay was quantified and demonstrated that exposure of SVG and U‐373MG glioma cells to PD 406976 suppressed PKC activity. Western blotting demonstrated reduced PKC‐β1, PKC‐γ and PKC‐τ protein content in cells treated with PD 406976. We determined that the growth inhibitory effect of PD 406976 was not as a result of apoptosis.
Anisotropy from full waveform inversion of multicomponent seismic data using a hybrid optimization method
Authors: Ji Ying , Singh Satish C.
Published: April 2005

Seismic waveforms contain valuable information about the media, but the waveform inversion is a non‐linear problem. We present a waveform inversion method that combines a local optimization method with a genetic algorithm to determine the anisotropic parameters of a horizontally stratified medium. Synthetic seismograms for a horizontally stratified anisotropic medium are calculated using the reflectivity technique. In the initial stage of the inversion, the global space‐sampling properties of the genetic algorithm are used to direct the search to the region close to the global solution. This solution is then further improved using a conjugate‐gradient method. The numerical experiments performed with noisy synthetic data show that our hybrid optimization method satisfactorily reconstructs the anisotropic parameters at a reasonable computing cost while the range of slowness is adequate. We found that (i) for small‐angle data neither single‐ nor multiple‐component data are sufficient to determine the anisotropic parameters uniquely; (ii) for medium‐angle data the multiple‐component data are sufficient to determine the anisotropic parameters exactly whereas the single‐component data are not sufficient; and (iii) for wide‐angle data, either single‐ or multiple‐component data are sufficient to determine the anisotropic parameters accurately.
Velocity–porosity relationships: Predictive velocity model for cemented sands composed of multiple mineral phases
Authors: Knackstedt Mark A. , Arns Christoph H. , Val Pinczewski W.
Published: April 2005

Computer simulations are used to calculate the elastic properties of model cemented sandstones composed of two or more mineral phases. Two idealized models are considered – a grain‐overlap clay/quartz mix and a pore‐lining clay/quartz mix. Unlike experimental data, the numerical data exhibit little noise yet cover a wide range of quartz/cement ratios and porosities. The results of the computations are in good agreement with experimental data for clay‐bearing consolidated sandstones.

The effective modulus of solid mineral mixtures is found to be relatively insensitive to microstructural detail. It is shown that the Hashin–Shtrikman average is a good estimate for the modulus of the solid mineral mixtures. The distribution of the cement phase is found to have little effect on the computed modulus–porosity relationships. Numerical data for dry and saturated states confirm that Gassmann's equations remain valid for porous materials composed of multiple solid constituents. As noted previously, the Krief relationship successfully describes the porosity dependence of the dry shear modulus, and a recent empirical relationship provides a good estimate for the dry‐rock Poisson's ratio.

From the numerical computations, a new empirical model, which requires only a knowledge of system mineralogy, is proposed for the modulus–porosity relationship of isotropic dry or fluid‐saturated porous materials composed of multiple solid constituents. Comparisons with experimental data for clean and shaly sandstones and computations for more complex, three‐mineral (quartz/dolomite/clay) systems show good agreement with the proposed model over a very wide range of porosities.
Temporary Liaisons: The Commitment of ‘Temps’ Towards Their Agencies*
Authors: Van Breugel Gerla , Van Olffen Woody , Olie René
Published: April 2005

abstract  The majority of research on organizational commitment has focused on commitment in traditional, ongoing and open‐ended relationships. The commitment of employees in non‐standard work arrangements such as temporary employment has been subject to much less theoretical and empirical investigation. In this study, we examine the affective and continuance commitment of temporary workers towards their agency and its determinants. We distinguish two groups of determinants: the process by which the temporary worker chose a particular agency and the support provided by the agency. The findings can be summarized as follows: (1) affective commitment among temps is generally higher than their continuance commitment; (2) having more alternative agencies to choose from (i.e., volition) does not enhance the commitment of temporary workers; (3) a public choice for a particular agency raises both types of commitment, whereas the perceived agency dependence created by the choice increases continuance, but not affective commitment; and (4) both types of commitment are positively influenced by agency supportiveness, reflected in the way the agency deals with problems, the career support it provides, and the way it keeps in close contact with its temporary workers. Finally, the results suggest that factors raising affective commitment may ‘spill over’ to increase continuance commitment.
Non-Stationary Spatiotemporal Analysis of Karst Water Levels
Authors: Dryden I. L. , Márkus L. , Taylor C. C. , Kovács J.
Published: April 2005

We consider non-stationary spatiotemporal modelling in an investigation into karst water levels in western Hungary. A strong feature of the data set is the extraction of large amounts of water from mines, which caused the water levels to reduce until about 1990 when the mining ceased, and then the levels increased quickly. We discuss some traditional hydrogeological models which might be considered to be appropriate for this situation, and various alternative stochastic models. In particular, a separable space–time covariance model is proposed which is then deformed in time to account for the non-stationary nature of the lagged correlations between sites. Suitable covariance functions are investigated and then the models are fitted by using weighted least squares and cross-validation. Forecasting and prediction are carried out by using spatiotemporal kriging. We assess the performance of the method with one-step-ahead forecasting and make comparisons with naïve estimators. We also consider spatiotemporal prediction at a set of new sites. The new model performs favourably compared with the deterministic model and the naïve estimators, and the deformation by time shifting is worthwhile.
The decline and fall of the European film industry: sunk costs, market size, and market structure, 1890–19271
Authors: BAKKER GERBEN
Published: April 2005

In the 1900s, the European film industry exported throughout the world, at times supplying half the US market. By 1920, however, European films had virtually disappeared from America, and had become marginal in Europe. Theory on sunk costs and market structure suggests that an escalation of sunk costs during a rapid US growth phase resulted in increased concentration; eight surviving companies dominated international film production and distribution forever after. European film companies, although overall profitable, could not take part, and after the war could not catch up. US, British, and French time series data for 1890–1930 support the theory.
Commercials, careers, and culture: travelling salesmen in Britain, 1890s–1930s*
Authors: FRENCH MICHAEL
Published: April 2005

Within the lower middle‐class, British commercial travellers established a strong fraternal culture before 1914. This article examines their interwar experiences in terms of income, careers, and associational culture. It demonstrates how internal labour markets operated, identifies the ways in which commercial travellers interpreted their role, and explores their social and political attitudes.
THE HISTORY OF WORDS BECOMES THE HISTORY OF THOUGHT
Authors: Kramer Lloyd
Published: April 2005

Action and Reaction: The Life and Adventures of a Couple. By Jean Starobinski.
ATHENS AND JERUSALEM: ROSENZWEIG, HEIDEGGER, AND THE SEARCH FOR AN ORIGIN
Authors: Bambach Charles
Published: April 2005

Rosenzweig and Heidegger: Between Judaism and German Philosophy. By Peter Eli Gordon.
Increased fetal RhD gene in the maternal circulation in early pregnancy is associated with an increased risk of pre‐eclampsia
Authors: Cotter Amanda M. , Martin Cara M. , O'Leary John J. , Daly Sean F.
Published: April 2005

Objective  To determine whether the fetal RhD gene is present in the maternal circulation in early pregnancy prior to the clinical manifestation of pre‐eclampsia.

Design  This is a nested case–control study.

Setting  Blood samples were obtained from patients attending for a first antenatal visit.

Sample  Cases were asymptomatic RhD negative women (n= 23) who subsequently developed pre‐eclampsia matched to RhD negative controls (n= 23) for parity and gestational age.

Methods  Real time PCR using TaqMan primers and probes directed against the RhD gene quantified fetal DNA in the maternal circulation.

Main outcome measures Quantity of RhD gene detected.

Results  As the copy number of RhD gene per millilitre of whole blood at 15 weeks of gestation increased, there was a significantly increased risk of developing pre‐eclampsia. There was a graded association between copy number of RhD gene in early pregnancy and severity of disease with controls having 6942, mild pre‐eclamptics 83,273 and severe pre‐eclamptics 285,793 copies/mL (logscale 3.6, 4.0 and 4.5, respectively).

Conclusion  Increased fetal RhD gene is present in the maternal circulation in early pregnancy in women who subsequently develop pre‐eclampsia and there appears to be a graded response between the quantity of fetal DNA and severity of pre‐eclampsia.
Antioxidants and preterm prelabour rupture of the membranes
Authors: Mathews Fiona , Neil Andrew
Published: April 2005

Objective  To investigate the relationships of dietary intakes and serum levels of antioxidant nutrients to the risk of prelabour rupture of the membranes preterm (PPROM).

Design  A prospective observational cohort study.

Setting  A district general hospital in the south of England.

Population  Eight hundred and twelve white nulliparous women with singleton pregnancies.

Methods  Serum antioxidant concentrations and dietary intakes were measured in the second trimester. Associations with the risk of PPROM were investigated.

Main outcome measure  Preterm prelabour rupture of the membranes.

Result  Serum concentrations of the antioxidant lutein, but no other nutrient, was associated with the risk of PPROM. Maternal smoke exposure (serum cotinine) also predicted PPROM. Women with high serum lutein concentrations (top third) in early pregnancy had four times greater risk than women in the lowest third (95% CI 1.3–11.9; P= 0.009) after adjusting for smoke exposure. Similar results were obtained using lutein levels from later pregnancy.

Conclusion  We found no evidence that antioxidant nutrients are protective against PPROM. Rather, high levels of lutein were associated with an increased risk.
Vergleich der Wirksamkeit verschiedener topischer Glukokortikoidcremes und ‐salben im Vasokonstriktionstest: Überlegenheit von Hydrocortisonbutyrat gegenüber Hydrocortison
Authors: Korting Hans Christian , Maslen Kirstin , Groß Gabi , Willers Christoph
Published: April 2005

Hintergrund: Topische Glukokortikoide sind Mittel der ersten Wahl zur Behandlung zahlreicher entzündlicher und hyperproliferativer Hauterkrankungen. Der Vasokonstriktionstest eignet sich zur Bestimmung der Wirkstärke von Kortikoiden.

Patienten und Methode: In die vorliegenden Studie wurden insgesamt 60 hautgesunde Probanden eingeschlossen. Drei Kortikoide und eine korrespondierende wirkstofffreie Grundlage wurden auf Basis von Creme‐ und Salben‐Zubereitungen in einer doppelblinden, randomisierten, intra‐individuellen klinischen Studie an hautgesunden Probanden mittels Vasokonstriktionstest untersucht. Es wurden die Wirkstärken von Hydrocortison, Hydrocortison‐17‐butyrat und Mometasonfuroat sowie Hydrocortison‐17‐butyrat und Placebo im Vergleich bestimmt.

Ergebnisse: Die Summenscores der klinischen Beurteilung betrugen für Hydrocortison 34 (Creme) und 18 (Salbe), für Hydrocortisonbutyrat 47 (Creme) und 55 (Salbe) und für Mometasonfuroat 57 (Creme) und 50 (Salbe). Der in der Chromametrie bestimmte Abblaßeffekt betrug für Hydrocortison 1,73 (Creme) und 1,48 (Salbe), für Hydrocortisonbutyrat 2,87 (Creme) und 3,26 (Salbe) und für Mometasonfuroat 2,98 (Creme) und 2,84 (Salbe).

Schlußfolgerungen: Bei der klinischen und chromametrischen Beurteilung der Vasokonstriktion wurde eine Wirksamkeit aller Verumzubereitungen gezeigt, wobei sich Hydrocortisonbutyrat als überlegen gegenüber Hydrocortison erwies.
COMPARISON OF ECHOCARDIOGRAPHY‐GUIDED AND FLUOROSCOPY‐GUIDED ENDOMYOCARDIAL BIOPSY TECHNIQUES
Authors: Nelson O. Lynne , Robbins Charles T.
Published: April 2005

The accuracy of bioptome placement for endomyocardial biopsy was evaluated using standard fluoroscopic guidance and compared simultaneously with two‐dimensional echocardiography in six healthy subadult grizzly bears (Ursus arctos horribilis). Despite perceived adequate positioning of the bioptome toward the septum when judged using fluoroscopy, only one out of the six placements were actually positioned in the right ventricular apex toward the septum when evaluated using two‐dimensional echocardiography. The bioptome was readily relocated to the right ventricular apex/septal location by echocardiography. The forceps were easily visualized at all times and the open cups were readily directed into the desired location for biopsy. Based on a subjective score for tissue quantity from 1 to 4 (poor to excellent), biopsies collected by echocardiographic‐guided technique had a mean score of 3.4, while biopsies collected by fluoroscopic‐guided technique had a mean score of 1.8. In summary, this study suggests that endomyocardial biopsy locations can be accurately positioned using two‐dimensional echocardiography with the advantages of less radiation, lower procedural costs, and direct visualization of the sampling site. Clear definition of endocardial surface as afforded by echocardiography may enhance tissue sample quality and lower potential complications from this procedure.
A URINARY BLADDER FIBROSARCOMA IN A YOUNG DOG
Authors: Olausson A. , Stieger S. M. , Loefgren S. , Gillingstam M.
Published: April 2005

A 14‐month‐old female dog, Gos d'Atura Catala was presented for a 7‐month‐history of reoccurring urinary tract infection. Using sonography, a focal multilobulated thickening of the urinary bladder wall was discovered. The solid mass was arising from the area of the ureteral papillae and bulging into the lumen of the bladder neck. The wall of the urethra was uniformly thickened. These findings were not considered typical for a generalized urinary tract infection but more indicative of local severe inflammation, neoplasia or hyperplasia in the area of the ureteral openings. The thickening of the urethra was suggestive of urethritis or neoplastic infiltration. Signs of metastasis were not detected on the thoracic radiographs or in the remainder of the abdominal ultrasound examination. A surgical excision of the multilobulated mass was performed and histologic examination was conducted. A fibrosarcoma in the lamina propria of the urinary bladder wall was diagnosed. Because of reoccurence of hematuria and unresponsiveness to therapy the dog was euthanized. Postmortem examination confirmed the diagnosis of fiborsarcoma in the urinary bladder. Additionally, neoplastic infiltration of the urethral wall and metastasis in the lungs and liver were detected histopathologically.
Late referral for assessment of renal failure
Authors: Kee Frank , Reaney Elizabeth A , Maxwell A Peter , Fogarty Damian G , Savage Gerard , Patterson C Christopher
Published: April 2005

It has been recommended that adult patients with a serum creatinine above 150 μmol/l should be referred to a nephrologist for specialist assessment. This study ascertained all patients in Northern Ireland with creatinine above this concentration in 2001 (n = 19 286 ) to see if this triggered referral within the subsequent year. After exclusion of those who were already known to a nephrologist and those who had acute renal failure, it was found that younger patients and diabetic patients were more likely to be referred. There was no difference in referral rates between male and female patients. However, only 6.5% of all non-diabetic subjects and 19% of diabetic patients were referred within 12 months after a first increased serum creatinine test.