bluuebunny/crossref_metadata_2025 huggingface dataset:
Dimensions of reengineering environment infrastructures
Authors: Ducasse S. , Tichelaar S.
Published: October 2003

Over the last decade many research groups and commercial companies have been developing reengineering environments. However, many design decisions such as support for multiple models, incremental loading of information, tool integration, entity grouping, and their impacts on the underlying meta‐model and resulting environment have remained implicit. Based on the experience accumulated while developing the Moose reengineering environment and on a survey of reengineering environments, we present a design space defined by a set of criteria that makes explicit the different options and especially their dependencies and trade‐offs. Using this design space, developers of future environments should have a better understanding of the problems they face and the impact of design choices. Copyright © 2003 John Wiley & Sons, Ltd.
Disorders of the parathyroid glands
Authors: Barber Penney J.
Published: October 2003

The three calcitropic hormones, parathyroid hormone (PTH), 1,25-dihydroxycholecalciferol and calcitonin are together responsible for calcium homeostasis in the mammal. Feline PTH is an 84 amino acid, single chain polypeptide with a molecular weight of 9449, which is secreted by the parathyroid glands. The principle secretagogue for PTH is a low plasma ionised calcium concentration, although both 1,25-dihydroxycholecalciferol and phosphate have significant roles in regulating PTH secretion. The ability to accurately measure circulating PTH in the cat has simplified the evaluation of disorders of calcium metabolism in this species. In primary parathyroid disorders the lesion is located within the parathyroid gland, with parathyroid secretion being inappropriate to the prevailing mineral balance. By contrast, in secondary conditions a pathological state out with the parathyroid gland alters mineral homeostasis and the parathyroid gland responds in an appropriate manner. The measurement of circulating PTH may then be used to determine if PTH secretion is appropriate to the prevailing calcium concentrations to differentiate primary from secondary disorders. Although primary hyper and hypoparathyroidism are generally considered rare endocrine conditions of the cat, the ability to measure PTH has led to their increasing recognition.
Church–state conflict in Moldova: the Bessarabian Metropolitanate
Authors: Turcescu Lucian , Stan Lavinia
Published: October 2003

The article’s main focus is the relationship between the re-established Bessarabian Orthodox Metropolitanate and the government of the post-Soviet Republic of Moldova. The article demonstrates that the Moldovan government refused recognition to the nascent church until 2002 primarily for two reasons: first and foremost, the Moscow Patriarchate opposed the idea of another Orthodox Christian church in Moldova outside of its jurisdiction; second, the government feared that the newly independent Republic of Moldova would fall under the influence of neighboring Romania, whose Orthodox Church offered patronage to the Bessarabian Metropolitanate. After a historical overview of the Orthodox Church in the Republic of Moldova, the article first presents and analyzes the history of the conflict between the Bessarabian Metropolitanate and the post-Soviet Moldovan government, and second, the European Court of Human Rights verdict ordering the government to recognize the Metropolitanate, before verdict’s implementation, and reactions to it. All these are done with an eye on intra-national relations among Moldova, Romania, and Russia, as well as those between the Romanian Orthodox Church and the Russian Orthodox Church in connection with this conflict.
Purification and phosphorylation of the effector protein NopL from Rhizobium sp. NGR234
Authors: Bartsev Alexander V. , Boukli Nawal M. , Deakin William J. , Staehelin Christian , Broughton William J.
Published: October 2003

Bacterial pathogens use type III secretion systems (TTSSs) to deliver virulence factors into eukaryotic cells. These effectors perturb host‐defence responses, especially signal transduction pathways. A functional TTSS was identified in the symbiotic, nitrogen‐fixing bacterium Rhizobium sp. NGR234. NopL (formerly y4xL) of NGR234 is a putative symbiotic effector that modulates nodulation in legumes. To test whether NopL could interact with plant proteins, in vitro phosphorylation experiments were performed using recombinant nopL protein purified from Escherichia coli as well as protein extracts from Lotus japonicus and tobacco plants. NopL serves as a substrate for plant protein kinases as well as purified protein kinase A. Phosphorylation of NopL was inhibited by the Ser/Thr kinase inhibitor K252a as well as by PD98059, a mitogen‐activated protein (MAP) kinase kinase inhibitor. It thus seems likely that, after delivery into the plant cell, NopL modulates MAP kinase pathways.
Synthetic peptides as models for intrinsic membrane proteins
Authors: Killian J.Antoinette
Published: October 2003

There are many ways in which lipids can modulate the activity of membrane proteins. Simply a change in hydrophobic thickness of the lipid bilayer, for example, already can have various consequences for membrane protein organization and hence for activity. By using synthetic transmembrane peptides, it could be established that these consequences include peptide oligomerization, tilt of transmembrane segments, and reorientation of side chains, depending on the specific properties of the peptides and lipids used. The results illustrate the potential of the use of synthetic model peptides to establish general principles that govern interactions between membrane proteins and surrounding lipids.
PKCδ inhibits PKCα‐mediated activation of phospholipase D1 in a manner independent of its protein kinase activity
Authors: Oka Masahiro , Okada Taro , Nakamura Shun-ichi , Ohba Motoi , Kuroki Toshio , Kikkawa Ushio , Nagai Hiroshi , Ichihashi Masamitsu , Nishigori Chikako
Published: October 2003

The regulation of phospholipase D1 (PLD1) by protein kinase C (PKC) isoforms was analyzed in human melanoma cell lines. 12‐O‐Tetradecanoylphorbol‐13‐acetate (TPA)‐induced PLD1 activation was suppressed by the introduction of PKCδ as well as its kinase‐negative mutant in MeWo cells, which contain PKCα but lack PKCβ. PLD activity was not affected by PKCδ in G361 cells, which have PKCβ but are deficient in PKCα. In MeWo cells introduced by PKCα and PLD1, the association of these proteins was observed, which was enhanced by the TPA treatment. In cells overexpressing PKCδ in addition to PKCα and PLD1, TPA treatment increased the association of PKCδ and PLD1, while it attenuated the association of PKCα and PLD1. These results indicate that PKCδ inhibits TPA‐induced PLD1 activation mediated by PKCα through the association with PLD1.
α‐Conotoxins EpI and AuIB switch subtype selectivity and activity in native versus recombinant nicotinic acetylcholine receptors
Authors: Nicke Annette , Samochocki Marek , Loughnan Marion L , Bansal Paramjit S , Maelicke Alfred , Lewis Richard J
Published: October 2003

The Xenopus laevis oocyte expression system was used to determine the activities of α‐conotoxins EpI and the ribbon isomer of AuIB, on defined nicotinic acetylcholine receptors (nAChRs). In contrast to previous findings on intracardiac ganglion neurones, α‐EpI showed no significant activity on oocyte‐expressed α3β4 and α3β2 nAChRs but blocked the α7 nAChR with an IC50 value of 30 nM. A similar IC50 value (103 nM) was obtained on the α7/5HT3 chimeric receptor stably expressed in mammalian cells. Ribbon AuIB maintained its selectivity on oocyte‐expressed α3β4 receptors but unlike in native cells, where it was 10‐fold more potent than native α‐AuIB, had 25‐fold lower activity. These results indicate that as yet unidentified factors influence α‐conotoxin pharmacology at native versus oocyte‐expressed nAChRs.
Comparative genome analysis of Campylobacter jejuni using whole genome DNA microarrays
Authors: Pearson B.M. , Pin C. , Wright J. , I’Anson K. , Humphrey T. , Wells J.M.
Published: October 2003

Whole genome DNA microarrays were constructed and used to investigate genomic diversity in 18 Campylobacter jejuni strains from diverse sources. New algorithms were developed that dynamically determine the boundary between the conserved and variable genes. Seven hypervariable plasticity regions (PR) were identified in the genome (PR1 to PR7) containing 136 genes (50%) of the variable gene pool. When comparisons were made with the sequenced strain NCTC11168, the number of absent or divergent genes ranged from 2.6% (40 genes) to 10.2% (163) and in total 16.3% (269) of the genes were variable. PR1 contains genes important in the utilisation of alternative electron acceptors for respiration and may confer a selective advantage to strains in restricted oxygen environments. PR2, 3 and 7 contain many outer membrane and periplasmic proteins and hypothetical proteins of unknown function that might be linked to phenotypic variation and adaptation to different ecological niches. PR4, 5 and 6 contain genes involved in the production and modification of antigenic surface structures.
Why do mammalian mitochondria possess a mismatch repair activity?
Authors: Mason P.A. , Lightowlers R.N.
Published: October 2003

All nucleated mammalian cells contain mitochondrial DNA, a small (approximately 15–17 kb) circular genome found in the matrix. This molecule is present in multiple copies, with numbers routinely exceeding 1000 per cell. Many pathogenic mutations of this genome have been reported, with the vast majority being highly recessive. A mismatch repair activity has been recently described in mitochondria that shows no strand bias for correcting point mutations. What could be the physiological function of such an activity? Mammalian mtDNA is remarkable in being a patchwork of many short repeat sequences. With reference to several recent publications, we hypothesise that the function of this activity is to preserve the mitochondrial genome by repairing short loop out sequences that would otherwise be lost as mitochondrial DNA polymerase gamma replicates the mitochondrial genome.
Photoconversion of matrix targeted GFP enables analysis of continuity and intermixing of the mitochondrial lumen
Authors: Jakobs Stefan , Schauss Astrid C. , Hell Stefan W.
Published: October 2003

We establish photoconversion of green fluorescent protein (GFP) as an optical ‘highlighter’ to investigate the continuity of the mitochondrial matrix in living budding yeast (Saccharomyces cerevisiae). Photoconversion of GFP resulting in a marked shift of the absorption and emission spectra to longer wavelengths is elicited, under low oxygen conditions, by irradiation with blue light. Photoconversion induced a several 100‐fold increase in red fluorescence of matrix targeted GFP without affecting cell viability. The color changing facilitates simple and effective regional optical marking in a conventional fluorescence microscope. We found the mitochondrial compartment of S. cerevisiae to generally consist of one luminally continuous large part and occasionally some additional smaller fragments. Separated fragments fuse within a few minutes to the large part, resulting in a rapid intermixing of the entire mitochondrial matrix compartment. In Δfis1 and Δdnm1 mutants restricted in outer membrane fission, the mitochondria are still luminally continuous, suggesting a tight coupling of inner and outer membrane fissions. Matrix constrictions frequently occurring in wild type cells as well as in Δfis1 and Δdnm1 mutants do not interfere with luminal continuity.
Factors affecting the performance of the acoustic ground discrimination system RoxAnn™
Authors: Wilding Thomas A , Sayer Martin D.J , Provost Paul G
Published: October 2003

The resolution, temporal variability and survey vessel speed dependence of the acoustic ground discrimination system RoxAnn™ was assessed over a 1 km2 area in Loch Linnhe on the west coast of Scotland. The resolution of the system was relatively poor and of the sediment parameters quantified (stone cover and sediment texture), only stone cover was consistently and significantly related to the RoxAnn™ output. The output showed considerable variability over the same ground when sampled within the same day and between days and months. The effect of survey vessel speed on the output was also significant but highly variable during all surveys. The apparent magnitude and unpredictable nature of the variation in the RoxAnn™ output have implications for the use of such systems in habitat mapping, particularly when surveying biological communities where there are only small differences in the physical properties of the seabed and also where monitoring temporal change. These aspects are discussed.
Specific sites in the Beta Interaction Domain of a schistosome Ca2+ channel β subunit are key to its role in sensitivity to the anti-schistosomal drug praziquantel
Authors: KOHN A. B. , ROBERTS-MISTERLY J. M. , ANDERSON P. A. V. , KHAN N. , GREENBERG R. M.
Published: October 2003

Praziquantel, the drug of choice against schistosomiasis, disrupts calcium (Ca2+) homeostasis in schistosomes via an unknown mechanism. Voltage-gated Ca2+ channels are heteromultimeric transmembrane protein complexes that contribute to impulse propagation and also regulate intracellular Ca2+ levels. β subunits modulate the properties of the pore-forming α1 subunit of high voltage-activated Ca2+ channels. Unlike other Ca2+ channel β subunits, which have current stimulatory effects, a β subunit subtype found in S. mansoni (SmβA) and S. japonicum (Sjβ) dramatically reduces current levels when co-expressed with Ca2+ channel α1 subunits in Xenopus oocytes. It also confers praziquantel sensitivity to the mammalian Cav2.3 α1 subunit. The Beta Interaction Domains (BIDs) of SmβA and Sjβ lack 2 conserved serines that each constitute a consensus site for protein kinase C (PKC) phosphorylation. Here, we use site-directed mutagenesis of schistosome β subunits to show that these unique functional properties are correlated with the absence of these consensus PKC sites in the BID. Furthermore, a second schistosome β subunit subtype contains both serines in the BID, enhances currents through α1 subunits, and does not confer praziquantel sensitivity. Thus, phosphorylation sites in the BID may play important roles in defining the modulatory properties and pharmacological sensitivities of schistosome Ca2+ channel β subunits.
Observations on the musculature and isolated muscle fibres of the liver fluke,Fasciola hepatica
Authors: KUMAR D. , McGEOWN J. G. , REYNOSO-DUCOING O. , AMBROSIO J. R. , FAIRWEATHER I.
Published: October 2003

The liver fluke,Fasciola hepaticarelies on a well-developed muscular system, not only for attachment, but for many aspects of its biology. Despite this, little is known about the system beyond the gross organization of the main somatic muscle layers. In the present study, a range of techniques have been applied toF. hepaticain order to understand more about various aspects of muscle organization, biochemistry (in terms of muscle proteins) and identity of isolated muscle fibres. Scanning electron microscopy has provided a direct visualizationin situof the somatic muscle layers and the organization of the muscle fibres within the ventral sucker. The muscle bundles contributing to the main somatic muscle layers are made up of up to 10 individual muscle fibres. Phalloidin staining for actin, in conjunction with confocal microscopy, confirmed the presence of 2 main somatic muscle layers (outer circular, inner longitudinal), beneath which lies a third layer of oblique muscle fibres. The use of propidium iodide in combination with phalloidin staining for actin demonstrated that the cell bodies associated with the 2 main somatic muscle layers are situated beneath the longitudinal muscle layer and are connected to their respective muscle fibres by short cytoplasmic processes. Myosin immunoreactivity was demonstrated in the somatic muscle layers and in the muscle layers surrounding various organ systems within the fluke. Double labelling for actin and myosin confirmed the co-localization of the 2 muscle proteins in the muscle fibres of the ventral sucker. Muscle fibres from the somatic muscle layers and the ventral sucker have been isolated and images obtained with phase-contrast microscopy and scanning electron microscopy. The muscle fibres contain actin and myosin, but lack a nucleus, the connection with the cell body having been broken during the isolation procedure.
TaqMan minor groove binder real-time PCR analysis of β-tubulin codon 200 polymorphism in small strongyles (Cyathostomin) indicates that the TAC allele is only moderately selected in benzimidazole-resistant populations
Authors: SAMSON-HIMMELSTJERNA G. VON , BUSCHBAUM S. , WIRTHERLE N. , PAPE M. , SCHNIEDER T.
Published: October 2003

TaqMan minor groove binder probes were evaluated as to their suitability for the real-time allelic discrimination of the β-tubulin codon 200 TTC/TAC single nucleotide polymorphism in cyathostomin species. Amplification of titrated cloned full-length β-tubulin cDNA revealed that the TaqMan minor groove binder PCR is capable of specifically detecting as few as 10 copies. Testing of DNA from single adult and larval stages of several different species of cyathostomin allowed reproducible genotyping of individual worms. Using the real-time PCR approach, the throughput of samples was considerably increased compared with conventional post-PCR readout procedure. Only 7·8% homozygous TAC L3 were found among 102 L3 which were genotyped from phenotypically BZ-resistant small strongyle populations. The percentages of the homozygous TTC and heterozygous TTC/TAC were 41·3% and 50·9%, respectively. This resulted in a total TAC-allele percentage of only 33·3%. These findings correspond to data obtained by genotyping of an experimentally selected BZ-resistant cyathostomin population. It is concluded that the β-tubulin codon 200 polymorphism is not the sole mechanism involved in the process of BZ resistance in cyathostomins.
Rodent malaria parasites suffer from the presence of conspecific clones in three-clonePlasmodium chabaudiinfections
Authors: DE ROODE J. C. , READ A. F. , CHAN B. H. K. , MACKINNON M. J.
Published: October 2003

We studied infection dynamics ofPlasmodium chabaudiin mice infected with 3 genetically distinct clones – 1 less virulent than the other 2 – either on their own or in mixtures. During the acute phase of infection, total numbers of asexual parasites in mixed-clone infections were equal to those produced by the 3 clones alone, suggesting strong in-host competition among clones. During the chronic phase of the infection, mixed-clone infections produced more asexual parasites than single-clone infections, suggesting lower levels of competition than during the acute phase, and indicating that a genetically diverse infection is harder to control by the host immune system. Transmission potential over the whole course of infection was lower from mixed-clone infections than from the average of the 3 single-clone infections. These results suggest that in-host competition reduces both growth rate and probability of transmission for individual parasite clones.
Togetherness amongPlasmodium falciparumgametocytes: interpretation through simulation and consequences for malaria transmission
Authors: GAILLARD F.-O. , BOUDIN C. , CHAU N. P. , ROBERT V. , PICHON G.
Published: October 2003

Previous experimental gametocyte infections ofAnopheles arabiensison 3 volunteers naturally infected withPlasmodium falciparumwere conducted in Senegal. They showed that gametocyte counts in the mosquitoes are, like macroparasite intakes, heterogeneous (overdispersed). They followed a negative binomial distribution, the overdispersion coefficient seeming constant (k=3·1). To try to explain this heterogeneity, we used an individual-based model (IBM), simulating the behaviour of gametocytes in the human blood circulation and their ingestion by mosquitoes. The hypothesis was that there exists a clustering of the gametocytes in the capillaries. From a series of simulations, in the case of clustering the following results were obtained: (i) the distribution of the gametocytes ingested by the mosquitoes followed a negative binomial, (ii) thekcoefficient significantly increased with the density of circulating gametocytes. To validate this model result, 2 more experiments were conducted in Cameroon. Pooled experiments showed a distinct density dependency of thek-values. The simulation results and the experimental results were thus in agreement and suggested that an aggregation process at the microscopic level might produce the density-dependent overdispersion at the macroscopic level. Simulations also suggested that the clustering of gametocytes might facilitate fertilization of gametes.
Erosional feedbacks and the oscillation of ice masses
Authors: Tomkin Jonathan H.
Published: October 2003

An analytical solution to the development of a glacier or ice sheet in a region where the underlying rock rises steadily shows that the ice mass oscillates in size, independefntly of changes in the climate, in response to a feedback in which ice thickness is linked to topography by ice‐induced erosion. The rate of vertical movement of the underlying rock uplift and the parameters governing ice erosion, ablation, and precipitation determine the period of oscillation. Two‐dimensional numerical simulations show that the tectonic uplift rate is the most important control on the period of oscillation and that the feedback period is likely to be between 10 and 100 kyr. An examination of sediment data from the Deep Sea Drilling Project shows evidence of ice mass oscillations in the Chugach‐St. Elias Mountains and in the Himalayas with periods consistent with those produced by the proposed mechanism. Localized changes in glacial extent may not therefore always be the consequence of climate change, and care must be taken in interpreting evidence of glacial advance and retreat.
Can the mantle entrain D″?
Authors: Namiki Atsuko
Published: October 2003

A series of laboratory experiments for mixing between the more viscous upper layer and the less viscous lower layer has been performed to study how the less viscous D″ mixes with the overlying more viscous mantle. Experimental results show that the style of entrainment when the more viscous layer overlies the less viscous layer is different from the opposite case. In the latter case the interface between the two layers moves upward, indicating that the more viscous lower layer asymmetrically entrains the less viscous upper layer. However, in the former case, an interfacial layer develops between the two layers and the interface does not move, indicating that the volumetric ratio of the two layers remains unchanged. It has been suggested that the compositional difference between mid‐ocean ridge basalts (MORB) and ocean island basalts (OIB) originates from the entrainment of D″ by the mantle plumes. The experimental results suggest that the mantle plume entrains only the interfacial layer, thus modifying the composition of OIB. The volume of D″ would remain unchanged since D″ is formed.
A global three‐dimensional model analysis of the atmospheric budgets of HCN and CH3CN: Constraints from aircraft and ground measurements
Authors: Li Qinbin , Jacob Daniel J. , Yantosca Robert M. , Heald Colette L. , Singh Hanwant B. , Koike Makoto , Zhao Yongjing , Sachse Glen W. , Streets David G.
Published: October 2003

We construct global atmospheric budgets of HCN and CH3CN through a three‐dimensional (3‐D) model simulation of the HCN‐CH3CN‐CO system constrained and evaluated with aircraft observations from the Transport and Chemical Evolution Over the Pacific (TRACE‐P) mission over the NW Pacific in February–April 2001. Observed background vertical gradients of HCN and CH3CN imply a dominant ocean sink for both gases, with deposition velocity of 0.13 cm s−1for both and saturation ratios of 0.79 for HCN and 0.88 for CH3CN. Observations for both gases in the free troposphere imply a dominant source from biomass burning. Enhancement of HCN observed in Chinese urban plumes is attributed tentatively to residential coal burning. Biomass burning and residential coal burning emission ratios relative to CO of 0.27% and 1.6%, respectively, for HCN, and of 0.20% and 0.25%, respectively, for CH3CN, are consistent with observations in biomass burning and Chinese urban plumes. They provide the best model simulation of the ensemble of TRACE‐P observations including vertical profiles and HCN‐CH3CN‐CO correlations. They also allow successful simulation of the long‐term observations of HCN columns at sites in the Northern Hemisphere, and of the CH3CN vertical distribution observed over the northern Indian Ocean. Global biomass burning and Asian residential coal burning sources in the model are 0.63 and 0.2 Tg N yr−1, respectively, for HCN and 0.47 and 0.03 Tg N yr−1, respectively, for CH3CN. Ocean uptake is the dominant sink for both gases, with oxidation by OH representing an additional minor sink. The resulting tropospheric lifetimes are 5.3 months for HCN and 5.8 months for CH3CN. The model predicts very low HCN and CH3CN concentrations at high southern latitudes, reflecting the assumption of a uniform saturation ratio for ocean uptake; observations in that region are needed. In the free troposphere, the dominance of biomass burning sources (70–85% for HCN and 90–95% for CH3CN) implies that both gases can be used as biomass burning tracers. In the boundary layer, CH3CN appears to be a better biomass burning tracer. More work is needed to identify the origin of the Chinese urban source of HCN.
Mantled and exhumed terrains in Terra Meridiani, Mars
Authors: Arvidson R. E. , Seelos F. P. , Deal K. S. , Koeppen W. C. , Snider N. O. , Kieniewicz J. M. , Hynek B. M. , Mellon M. T. , Garvin J. B.
Published: October 2003

Hematite‐bearing deposits in the Terra Meridiani region of Mars constitute the top stratum of a partially eroded layered complex that covers dissected Noachian‐aged cratered terrain. The hematite unit consists of dark plains and dunes covering a bright substrate. This substrate is fully exposed beyond the borders of the hematite‐bearing deposit and consists of polygonal ground separated by ridges or valleys, together with layered deposits that have been eroded into a variety of landforms. The complex is partially covered by a regional‐scale aeolian mantle that thickens toward the north. The hematite‐bearing stratum exhibits low albedoes, pulse widths, and intermediate thermal inertias, whereas the underlying unit exhibits high values of these parameters. Both units have spectral emissivity signatures similar to those for the low albedo cratered terrain to the south, with the addition of hematite for the top stratum. The complex is interpreted to consist of extensive plains‐forming lava flows and tephra deposits emplaced during an extensional regime and at least partially buried by an aeolian mantle. Aeolian stripping of the mantle exposed much of the complex and differentially eroded the deposits to produce the landforms existent today. Exploration of the hematite‐bearing deposits by the 2003 Mars Exploration Rover, “Opportunity,” will allow testing of the hypotheses presented since this stratum has been locally reworked into dunes that only partially cover the underlying brighter portion of the complex. In particular, the rover‐based measurements will allow us to test the extent to which the unusual remote‐sensing properties of the units indicate aqueous alteration.
Validation of a watershed model without calibration
Authors: Vogel Richard M. , Sankarasubramanian A.
Published: October 2003

Traditional approaches for the validation of watershed models focus on the “goodness of fit” between model predictions and observations. It is possible for a watershed model to exhibit a “good” fit, yet not accurately represent hydrologic processes; hence “goodness of fit” can be misleading. Instead, we introduce an approach which evaluates the ability of a model to represent the observed covariance structure of the input (climate) and output (streamflow) without ever calibrating the model. An advantage of this approach is that it is not confounded by model error introduced during the calibration process. We illustrate that once a watershed model is calibrated, the unavoidable model error can cloud our ability to validate (or invalidate) the model. We emphasize that model hypothesis testing (validation) should be performed prior to, and independent of, parameter estimation (calibration), contrary to traditional practice in which watershed models are usually validated after calibrating the model. Our approach is tested using two different watershed models at a number of different watersheds in the United States.
East Anatolian high plateau as a mantle‐supported, north‐south shortened domal structure
Authors: Şengör A. M. C. , Özeren Sinan , Genç Tugrul , Zor Ekrem
Published: October 2003

The East Anatolian High Plateau is a region of average ∼2 km elevation a.s.l. exhibiting active diffuse N‐S shortening and widespread Pliocene to recent volcanicity. Its elevation was hitherto thought to result from a presumed crustal thickness of ±55 km. Seismic data collected by a new network of 29 seismograph stations have shown, however, that its crustal thickness is only some 45 km. Combined with observations on Pn and Sn phases, this shows that most of the East Anatolian High Plateau is devoid of mantle lithosphere. Areas of no mantle lithosphere are inferred to coincide broadly with the extent of the East Anatolian Accretionary Complex, a subduction‐accretion prism of late Cretaceous to earliest Oligocene age. The absence of mantle lithosphere is ascribed to breakoff of northward subducted slab beneath the prism and the widespread vulcanicity to melting its lower levels because of direct contact with hot astenosphere. The East Anatolian High Plateau is thus supported not by thick crust, but by hot mantle.
Break‐up of the largest Arctic ice shelf and associated loss of an epishelf lake
Authors: Mueller Derek R. , Vincent Warwick F. , Jeffries Martin O.
Published: October 2003

Field observations and RADARSAT imagery of the Ward Hunt Ice Shelf (lat. 83°N, long. 74°W), Nunavut, Canada, show that it broke in two over the period 2000 to 2002, with additional fissuring and further ice island calving. The fracturing caused the drainage of an ice‐dammed epishelf lake (Disraeli Fiord), a rare ecosystem type. Reductions in the freshwater volume of Disraeli Fiord occurred from 1967 to the present and accompanied a significant rise in mean annual air temperature over the same period in this far northern region. The recent collapse of ice shelves in West Antarctica has been interpreted as evidence of accelerated climate change in that region. Similarly, the inferred thinning and observed fragmentation of the ice shelf, plus the drainage of the epishelf lake, are additional evidence for climate change in the High Arctic.
A ∼1.7‐year quasi‐periodicity in cosmic ray intensity variation observed in the outer heliosphere
Authors: Kato C. , Munakata K. , Yasue S. , Inoue K. , McDonald F. B.
Published: October 2003

The wavelet transform technique has been applied to investigate the periodicities longer than a year in cosmic ray intensity variations observed at the Voyager spacecraft and at the Earth. We found significant ∼1.7‐ and ∼1.3‐year periodic components in the cosmic ray intensity variation in the outer heliosphere during the 1980s (solar cycle 21) and the 1990s (solar cycle 22), respectively. This property is consistent with the result of the wavelet analysis of the cosmic ray intensity variations observed at several Neutron Monitors (NMs) and also with previous reports about these periodicities using several plasma parameters, such as the solar wind speed and geomagnetic indices, for example. As comparing with the interplanetary magnetic field (IMF) and solar flare indices, causal relation between energy release from the Sun and the ∼1.7‐year quasi‐periodicity is suggested.
Toward aerosol/cloud condensation nuclei (CCN) closure during CRYSTAL‐FACE
Authors: VanReken Timothy M. , Rissman Tracey A. , Roberts Gregory C. , Varutbangkul Varuntida , Jonsson Haflidi H. , Flagan Richard C. , Seinfeld John H.
Published: October 2003

During July 2002, measurements of cloud condensation nuclei were made in the vicinity of southwest Florida as part of the Cirrus Regional Study of Tropical Anvils and Cirrus Layers‐Florida Area Cirrus Experiment (CRYSTAL‐FACE) field campaign. These observations, at supersaturations of 0.2 and 0.85%, are presented here. The performance of each of the two CCN counters was validated through laboratory calibration and an in situ intercomparison. The measurements indicate that the aerosol sampled during the campaign was predominantly marine in character: the median concentrations were 233 cm−3 (at S = 0.2%) and 371 cm−3 (at S = 0.85%). Three flights during the experiment differed from this general trend; the aerosol sampled during the two flights on 18 July was more continental in character, and the observations on 28 July indicate high spatial variability and periods of very high aerosol concentrations. This study also includes a simplified aerosol/CCN closure analysis. Aerosol size distributions were measured simultaneously with the CCN observations, and these data are used to predict a CCN concentration using Köhler theory. For the purpose of this analysis, an idealized composition of pure ammonium sulfate was assumed. The analysis indicates that in this case, there was good general agreement between the predicted and observed CCN concentrations: at S = 0.2%, Npredicted/Nobserved = 1.047 (R2 = 0.911); at S = 0.85%, Npredicted/Nobserved = 1.201 (R2 = 0.835). The impacts of the compositional assumption and of including in‐cloud data in the analysis are addressed. The effect of removing the data from the 28 July flight is also examined; doing so improves the result of the closure analysis at S = 0.85%. When omitting that atypical flight, Npredicted/Nobserved = 1.085 (R2 = 0.770) at S = 0.85%.
An integrated approach to mixing sensitivities in tropospheric chemistry: A basis for the parameterization of subgrid‐scale emissions for chemistry transport models
Authors: Esler J. G.
Published: October 2003

The net effect on the global atmosphere of a continuous isolated chemical source is considered under idealized conditions. A general framework is described that allows Mi, the steady state global perturbation to the ith species due to the source, to be calculated. This is achieved by exploiting the fact that once the emissions are sufficiently dilute, far from the source, they decay with the timescales of the chemical eigenstates of the background atmosphere. Both Mi and the level of excitation of the longer‐lived eigenstates are shown to depend on the details of the mixing of emissions near the source. If the details of the dilution of the emissions plume are known, it is also shown that “equivalent emissions” can be calculated. Equivalent emissions are designed so that when diluted instantaneously into the background atmosphere they result in the same global perturbation to each species as the original slowly diluted plume. The framework is then applied to test the sensitivity to mixing of a simple O3‐NOx‐CO‐HOx tropospheric chemistry system. Mi is calculated for a NO‐CO source of constant strength as the mixing scenario undergone by the emissions is varied. The global increase in O3 due to the source is found to increase with the rate at which emissions are mixed, whereas the global increase in CO is reduced. The equivalent emissions for each plume dilution mechanism are then calculated. In a simple plume box model it is shown that the equilibrium state obtained when the model is forced by emissions that are first diluted in entraining plumes can be reproduced in a standard box model (i.e., with instantaneous mixing of emissions) by the corresponding equivalent emissions. It is argued that the concept of equivalent emissions can be exploited straightforwardly to derive a parameterization of unresolved subgrid plumes in order to reduce systematic error in global models.
Implications of coral reef buildup for the controls on atmospheric CO2since the Last Glacial Maximum
Authors: Ridgwell Andy J. , Watson Andrew J. , Maslin Mark A. , Kaplan Jed O.
Published: October 2003

We examine the effect on atmospheric CO2of the occurrence of increased shallow water carbonate deposition and regrowth of the terrestrial biosphere following the last glacial. We find that contrary to recent speculations that changes in terrestrial carbon storage were primarily responsible for the observed ∼20 ppmv late Holocene CO2rise, a more likely explanation is coral reef buildup and other forms of shallow water carbonate deposition during this time. The importance of a responsive terrestrial carbon reservoir may instead be as a negative feedback restricting the rate of CO2rise possible in the early stages of the deglacial transition. This separation in time of the primary impacts of regrowth of the terrestrial biosphere and increased shallow water carbonate deposition explains the occurrence of an early Holocene carbonate preservation event observed in deep‐sea sediments. We demonstrate that their combined influence is also consistent with available proxy estimates of deep ocean carbonate ion concentration changes over the last 21 kyr. Accounting for the processes that act on the carbonate chemistry of the ocean as a whole then allows us to place strong constraints on the nature of the remaining processes that must be operating at the deglacial transition. By subtracting the net CO2effect of coral reef buildup and terrestrial biosphere regrowth from recent high‐resolution ice core data, we highlight two periods, from 17.0 to 13.8 kyr and 12.3 to 11.2 kyr BP characterized by sustained rapid rates of CO2increase (>12 ppmv kyr−1). Because these periods are coincident with Southern Hemisphere “deglaciation,” we argue that changes in the biogeochemical properties of the Southern Ocean surface are the most likely cause.
Expression of TGF‐alpha in neuroendocrine tumours of the distal colon and rectum
Authors: BACK WALTER , ROHR GERHARD , BLEYL UWE
Published: October 2003

Aim. Transforming growth factor alpha (TGF‐alpha) has been localized in neuroendocrine L‐cells of the colon and rectum in previous studies. We examined whether neuroendocrine tumours with L‐cell differentiation express TGF‐alpha. Experimental design. Immunohistochemistry was performed for proglucagon‐ and pro‐pancreatic polypeptide derivatives, as well as for TGF‐alpha, and epidermal growth factor receptor (EGFR) using paraffin sections from 16 neuroendocrine tumours of the colon and rectum. Also, in situ hybridization for TGF‐alpha and proglucagon was carried out. Main results. A strong expression of TGF‐alpha at the protein level can be shown for neuroendocrine tumours of the hindgut. In one third of our cases we found a strong hybridization signal and in two thirds a moderate signal for TGF‐alpha. The immunohistological phenotype concerning gut hormones is highly heterogeneous. Glucagon‐like peptide 2 (GLP2) in our series was the most sensitive immunohistological hormone marker. Major conclusions. The immunophenotype of colorectal neuroendocrine tumours regarding hormone markers is heterogeneous. The expression of TGF‐alpha corresponds to the immunohistological profile of normal L‐cells. TGF‐alpha, especially in the neuroendocrine L‐cells, most probably acts as a multifunctional trophic factor responsible for cellular integrity and survival, and not as an oncogenic growth factor.
Nanobacteria promote crystallization of psammoma bodies in ovarian cancer
Authors: SEDIVY ROLAND , BATTISTUTTI WALTER B.
Published: October 2003

Serous papillary adenocarcinomas of the ovary are often associated with microcalcifications, namely psammoma bodies. Archebacteria such as nanobacteria are, for example, involved in kidney stone formation. Nanobacteria deserve close scrutiny as their cytotoxicity and ability to cross the placenta present a potential clinical risk. In this study we investigated whether nanobacteria are associated with psammoma bodies in ovarian cancer. We identified in all seven carcinomas with multiple psammoma body nanobacterial antigens in histological specimens and in the ascitic fluid. Control cases of adenocarcinomas without such calcifications did not present nanobacterial antigens. This finding indicates that apart from non‐malignant conditions, nanobacteria could also be found in cancer. Hence, nanobacterial infection may be of clinical importance as these bacteria are related to microcalifications in ovarian cancer.
Cholera toxin protects against action by Clostridium difficile toxin A
Authors: LÖNNROTH IVAR , LANGE STEFAN , JENNISCHE EVA , JOHANSSON EWA , JONSON INGELA , TORRES JAVIER
Published: October 2003

The protein antisecretory factor (AF) inhibits intestinal fluid secretion induced by the cholera toxin (CT) and Clostridium difficile toxin A (CDA). The present work investigated whether CT‐induced AF protects against the enterotoxin action by CDA. Rats were pretreated perorally with CT or buffer as control, whereafter CDA‐induced fluid secretion and cytotoxicity was tested in vivo in ligated intestinal loops; the mucosal level of AF was estimated using the Western blot technique. Rats given repeated peroral doses of CT became tolerant to CDA, the inhibition of fluid secretion and of cytotoxicity being 79% in eight out of nine animals. The repeated CT‐treatment also induced long‐lasting rise of AF in the mucosal epithelium. Recombinant AF given either perorally or intravenously inhibited both fluid secretion and cytotoxicity by CDA; similar results were obtained with a truncated 16‐mer AF peptide. In conclusion: peroral CT‐treatment induced tolerance to CDA in rat small intestine. The tolerance was probably mediated by AF induced via action of cholera toxin on the enteric nervous and immune system.
A mouse model for acute otitis media
Authors: MELHUS ÅSA , RYAN ALLEN F.
Published: October 2003

To induce acute otitis media in the mouse and to describe the clinical and bacteriological course of the infection, middle ears of BALB/c, Swiss‐Webster and C57BL/6 mice were inoculated with Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis. Systemic and local changes were monitored by clinical observations, otomicroscopy, and analysis of bacterial samples from blood and middle ears. Agglutination of mouse erythrocytes by M. catarrhalis was also tested. Depending on bacterial strain, bacterial dose, and mouse strain three responses were identified: acute otitis media, otitis media with serous effusion, or no reaction. BALB/c mice were the most susceptible animals. On day 3, 76% of the BALB/c mice had developed middle ear infection, 50% had a positive middle ear culture, 56% were bacteremic, and 10% had succumbed to a disseminated infection. The local infections lasted approximately a week. Animals which survived recovered without permanent deterioration or otomicroscopically discernible changes. In no case did M. catarrhalis induce a culture‐positive middle ear infection, possibly due to an inability to agglutinate the mouse erythrocytes. The mouse model can become a useful tool in studies of pneumococcal and H. influenzae‐induced otitis media, but the bacterial dose has to be carefully titrated and adjusted to the chosen mouse strain.
Travel schedules to the high arctic: barnacle geese trade‐off the timing of migration with accumulation of fat deposits
Authors: Prop Jouke , Black Jeffrey M. , Shimmings Paul
Published: October 2003

On their way from the wintering area to the breeding grounds in Spitsbergen, barnacle geese Branta leucopsis stage on islands off the coast of Norway. The aim of this study was to describe when the geese migrate in relation to the body stores deposited and explore questions related to the concept of optimal migration schedules and on the possible mechanisms involved. We estimated fat stores by repeated assessments of the abdominal profile index of individually marked females throughout staging. Reproductive success was derived from observations of the same individuals later in the annual cycle. Females arriving late, or with low fat stores at arrival, achieved higher fat deposition rates, probably by spending more time foraging. But they were unable to match final fat scores of birds that arrived earlier or with larger fat stores. Reproductive success was correlated with the timing of migration and individuals departing at intermediate dates achieved highest success. The exact date of peak reproductive success depended on the size of fat stores accumulated, such that low‐quality birds (depositing less fat) benefited most from an early departure to the breeding grounds. Observations in the breeding colonies showed that these birds did not initiate a nest earlier but they spent a longer time in Spitsbergen before settling. The length of stay in Norway was close to the prediction derived from an optimisation model relating spring events to eventual breeding success. Poorest performing birds stayed longer than expected, perhaps depositing more fat to avoid the risk of starvation. Two possible mechanisms of the timing of migration were contrasted and it seemed that the geese departed for migration as soon as they were unable to accumulate any more fat stores.
Spring migration routes and timing of Greenland white‐fronted geese – results from satellite telemetry
Authors: Fox Anthony D . , Glahder Christian M . , Walsh Alyn J .
Published: October 2003

Greenland white‐fronted geese accumulate body mass throughout late winter in preparation for migration after mid‐April to spring staging areas in Iceland. This analysis presents field assessment of abdominal fat deposits (API) from large samples of marked birds which showed increasing rates of fuel deposition throughout January–April. Historical records show that geese rarely depart en masse before 17 April, a pattern followed by all but one of the tagged birds. Timed positions obtained from 12 geese fitted with satellite transmitters in 1997, 1998 and 1999 suggested that all geese departed winter quarters on tailwinds between 16 and 19 April. Tracked geese flew directly to staging areas in Iceland, although one staged for 10 days in Northern Ireland in 1997 and another may have stopped briefly in western Scotland. Average migration duration of all tagged birds departing Ireland (including the 1997 bird that stopped over within Ireland) was 25 hours (range 13–77). Four geese apparently overshot and returned to Iceland during strong E to ESE winds. APIs in Iceland showed more rapid and linear increases in stores during the mean 19‐day (range 13–22) staging period there than on the winter quarters. Geese continued their migration to Greenland when APIs attained or exceeded levels at departure from Ireland and all departed on assisting tailwinds between 1 and 11 May. Tracked birds continued the journey to West Greenland in between 24 and 261 (mean 82) hours, although one bird turned back during the traverse of the Greenland Ice Cap and summered on the east coast. Seven of the birds staged for 1–20 hours at, or near, the East Greenland coast and several made slow progress crossing the inland ice, all in the direction of their ultimate destination (i.e. not necessarily taking the lowest or shortest crossing routes). It is suggested that the energy‐savings of departing on tailwinds may favour geese to wait for such conditions once threshold fat storage levels have been reached, but more research is needed to confirm this.