bluuebunny/crossref_metadata_2025 huggingface dataset:
On axisymmetric intrusive gravity currents: the approach to self-similarity solutions of the shallow-water equations in a linearly stratified ambient
Authors: Zemach Tamar , Ungarish Marius
Published: June 2007

The axisymmetric intrusion of a fixed volume of fluid, which is released from rest and then propagates radially at the neutral buoyancy level in a deep linearly stratified ambient fluid, is investigated. Attention is focused on the development of self-similar propagation. The shallow-water equations representing the high-Reynolds-number motion are used. For the long-time motion, an analytical similarity solution indicates propagation with
t
1/3
, but the shape is peculiar: the intrusion propagates like a ring with a fixed ratio of inner to outer radii; the inner domain contains clear ambient fluid. To verify the similarity analytical prediction, a long-time finite-difference solution with realistic initial conditions was performed. To avoid accumulation of numerical errors, the problem was reformulated in terms of new variables. It is shown that the numerical solution has a ‘tail-ring’ shape. The ‘tail’ decays like
t
−2
and the ‘ring’ tends to the analytical similarity prediction. The initial geometry of the lock does not influence this result. Comparison with the non-stratified case is also presented. It was found that for the non-stratified case, there is a stage of propagation in which the intrusion has a similar ‘tail-ring’ form; however, this stage is only a transient to a self-similar shape which is different from that obtained for the stratified ambient.
Spatial structure inhibits the rate of invasion of beneficial mutations in asexual populations
Authors: Habets Michelle G.J.L , Czárán Tamás , Hoekstra Rolf F , de Visser J. Arjan G.M
Published: June 2007

Populations in spatially structured environments may be divided into a number of (semi-) isolated subpopulations due to limited offspring dispersal. Limited dispersal and, as a consequence, local competition could slow down the invasion of fitter mutants, allowing the short-term coexistence of ancestral genotypes and mutants. We determined the rate of invasion of beneficial mutants ofEscherichia coli, dispersed to different degrees in a spatially structured environment during 40 generations, experimentally and theoretically. Simulations as well as experimental data show a decrease in the rate of invasion with increasingly constrained dispersal. When a beneficial mutant invades from a single spot, competition with the ancestral genotype takes placeonlyalong the edges of the growing colony patch. As the colony grows, the fitness of the mutant will decrease due to a decrease in the mutant's fraction that effectively competes with the surrounding ancestor. Despite its inherently higher competitive ability, increased intragenotype competition prevents the beneficial mutant from rapidly taking over, causing short-term coexistence of superior and inferior genotypes.
30 years of finite-gap integration theory
Authors: Matveev Vladimir B
Published: June 2007

The method of finite-gap integration was created to solve the periodic KdV initial problem. Its development during last 30 years, combining the spectral theory of differential and difference operators with periodic coefficients, the algebraic geometry of compact Riemann surfaces and their Jacobians, the Riemann theta functions and inverse problems, had a strong impact on the evolution of modern mathematics and theoretical physics. This article explains some of the principal historical points in the creation of this method during the period 1973–1976, and briefly comments on its evolution during the last 30 years.
Phylogenetic relationships of Pseudis and Lysapsus (Anura, Hylidae, Hylinae) inferred from mitochondrial and nuclear gene sequences
Authors: Aguiar O. , Bacci M. , Lima A. P. , Rossa‐Feres D. C. , Haddad C. F. B. , Recco‐Pimentel S. M.
Published: June 2007

The previous uncertain placement of Lysapsus and Pseudis within the neobatrachians was recently resolved by molecular and morphological studies, which supported them as members of the Hylinae subfamily. Their inter‐ and intrageneric relationships, however, have long been under debate and no studies shed light on these questions. Aiming to elucidate such questions, this paper used 3.2 kb comprising the mitochondrial genes 12S, tRNA valine, 16S and cytochrome b, and the nuclear exon 1 coding for rhodopsin, to all representatives of both genera (except to two subspecies of Pseudis paradoxa). The results identified three major clades: the clade 1 was composed by Lysapsus species and subspecies; clade 2 included the subspecies of the Pseudis paradoxa (Pseudis paradoxa paradoxa, P. paradoxa platensis and P. paradoxa occidentalis), P. fusca, P. bolbodactyla and P. tocantins, and clade 3 was composed by Pseudis southern Brazil species (Pseudis cardosoi and P. minuta). As closely related taxa we found Pseudis minuta + P. cardosoi; P. tocantins + P. fusca, and the subspecies within each genus. Evidence that Pseudis is not monophyletic with respect to Lysapsus was found and we suggest Lysapsus to be a junior synonym of Pseudis. Based on pair‐wise comparison among gene sequences, we also suggest that the subspecies of Pseudis paradoxa and Lysapsus limellum must be considered as full species.

© The Willi Hennig Society 2007.
Parallel evolution of lichen growth forms in the family Roccellaceae (Arthoniales, Ascomycota)
Authors: Tehler Anders , Irestedt Martin
Published: June 2007

The phylogenetic relationships within the family Roccellaceae (lichen fungi) were investigated. Seventy‐two nucleotide sequences of the nuclear large subunit ribosomal RNA gene (LSU) and the second largest RNA polymerase subunit (RPB2) were newly obtained from 48 taxa. The family Roccellaceae was highly supported as monophyletic. The fruticose growth habit has evolved or been lost multiple times in the family and several times even within genera. In Roccellina with 31 species it has evolved three times and in Pentagenella with three species it has been lost once. The genera Roccella and Roccellina were found paraphyletic as two Roccella species nested with Roccellina. The non‐fruticose genus Roccellina was emended to include these two fruticose species as well as the monotypic, fruticose genus Roccellaria. As a result of the phylogenetic analyses six new nomenclatural combinations were made: Pentagenella corallina (Follm. and Peine) Tehler, Pentagenella ligulata (Peine and Follm.) Tehler, Roccellina cumingiana (Gay) Tehler, Roccellina hypomecha (Ach.) Tehler, Roccellina mollis (Hampe) Tehler, Roccellina portentosa (Mont. ex Gay) Tehler. Roccella is mainly distributed on the northern hemisphere while Roccellina is mainly distributed on the southern hemisphere. The Roccella species present on the Galapagos Islands are related to those in California and the northern hemisphere not, as was generally believed, to those in Chile and the southern hemisphere. The present data set may indicate that Bayesian analysis can give misleading topologies and overestimated posterior support values when insufficiently sampled taxa are included in an otherwise well sampled data set.

© The Willi Hennig Society 2007.
One‐carbon metabolism‐related gene polymorphisms and risk of head and neck squamous cell carcinoma: Case–control study
Authors: Suzuki Takeshi , Matsuo Keitaro , Hasegawa Yasuhisa , Hiraki Akio , Wakai Kenji , Hirose Kaoru , Saito Toshiko , Sato Shigeki , Ueda Ryuzo , Tajima Kazuo
Published: June 2007

Low consumption of vegetables and fruits, which leads to insufficient folate intake, is associated with increased risk of several types of cancer, including head and neck squamous cell carcinoma (HNSCC). Functional polymorphisms in genes encoding one‐carbon metabolism enzymes, such as methylenetetrahydrofolate reductase (MTHFR C677T and A1298C), methionine synthase (MTR A2756G), methionine synthase reductase (MTRR A66G) and thymidylate synthase (TS), influence folate metabolism and thus might impact on HNSCC risk. We conducted a case‐control study with 237 HNSCC cases newly and histologically diagnosed and 711 age‐ and sex‐matched non‐cancer controls to clarify associations with these five polymorphisms. Gene–environment interactions between polymorphisms and smoking and drinking habit and folate consumption were also evaluated by logistic regression analysis. Dietary folate intake was inversely associated with HNSCC risk. None of the polymorphisms showed any significant impact on HNSCC risk by genotype alone, but we found interactions between drinking habit and MTHFR C667T (P = 0.04), MTR A2756G (P = 0.04) and MTRR A66G (P = 0.03) polymorphisms. The results suggest that there may be interactions between one‐carbon metabolism‐related polymorphisms and alcohol drinking for HNSCC risk. (Cancer Sci 2007; 98: 1439–1446)
COMPARISON OF THE EFFECTS OF VITAMIN E AND/OR QUERCETIN IN ATTENUATING CHRONIC CYCLOSPORINE A‐INDUCED NEPHROTOXICITY IN MALE RATS
Authors: Zal Fatemeh , Mostafavi‐Pour Zohreh , Vessal Mahmood
Published: June 2007

The aim of the present study was to investigate the effects of vitamin E and/or quercetin (Q) on renal function, oxygen radical concentrations in the kidney and some anti‐oxidant enzyme activities in rats treated with cyclosporine A (CsA).

Groups of rats (270 ± 15 g), on standard rat chow and water, received all their treatments by gavage for either 4 or 8 weeks. Control groups received either olive oil (0.5 mL) or 25% ethanol (0.5 mL) + olive oil (0.5 mL) per day as vehicle. All experimental groups received 25 mg CsA/kg per day in 0.5 mL olive oil. The vitamin E group received 100 mg vitamin E/kg per day in olive oil in addition to CsA treatment. The quercetin group received 15 mg of Q/kg per day in 0.5 mL of 25% ethanol in addition to CsA treatment. The vitamin E + quercetin group received the two anti‐oxidants at the concentrations given in addition to CsA treatment.

Quercetin, at a concentration less than one‐quarter of vitamin E, was more efficient in lowering blood urea nitrogen, serum creatinine and kidney malondialdehyde in CsA‐treated rats. However, neither of the two anti‐oxidants was able to normalize these analytes to control values after either 4 or 8 weeks treatment.

Quercetin (50 µmol/kg per day) elevated all renal anti‐oxidant enzyme activities to values observed in the negative controls. However, vitamin E (232 µmol/kg per day) only normalized glutathione peroxidase activity at the end of either 4 or 8 weeks treatment. Combination treatment with the two anti‐oxidants abolished all the ill‐effects of CsA.

Combination treatment with the two anti‐oxidants of renal transplant patients receiving CsA may be beneficial in ameliorating the chronic nephrotoxic effects of the important immunosuppressive drug CsA.
EFFECT OF ANGIOTENSIN AT1 RECEPTOR ANTAGONIST ON d‐GALACTOSAMINE‐INDUCED ACUTE LIVER INJURY
Authors: Chan Herman , Leung Po‐Sing , Tam Michael S‐C
Published: June 2007

Acute liver injury is a severe disease in which metabolic homeostasis is affected. The presence of liver cell death triggers a cascade of inflammatory responses leading to various degrees of liver damage. The pathophysiology of liver injury is complex, involving an interplay between parenchymal and non‐parenchymal cells.

There is increasing evidence for a role of the local renin–angiotensin system (RAS) in liver cell death, inflammatory response and liver regeneration. It has been shown that the local RAS plays an important regulatory role in a variety of tissues. In experimental hepatic fibrogenesis, the angiotensin AT1 receptor (AT1R) blocker losartan has been shown to be able to attenuate transforming growth factor‐b1 activity and collagen gene expression.

In the present study, using a d‐galactosamine (GalN)‐induced liver failure rat, AT1R were localized around the centrilobular region, which was not evident in normal liver. Blood tests showed an elevation of total bilirubin and alanine aminotransferase. Furthermore, there was an increase in tissue‐specific inhibitor of metalloproteinase (TIMP)‐1 protein in the liver. Losartan treatment was able to reduce all these parameters. Levels of TIMP‐1 protein were reduced by 1.5‐ and 1.56‐fold on Days 1 and 3, respectively (both P < 0.05), in the losartan‐treated group relative to the GalN‐treated group. The survival rate of the losartan‐treated group was significantly higher than that of the GalN‐treated group (5 day survival 85 vs 42.5%, respectively; P < 0.05).

In conclusion, the AT1R blocker losartan suppresses GalN‐induced liver injury. This may indicate that AT1R blockers may have therapeutic potential in the treatment of acute liver injury.
REGULATION OF NOGO‐B EXPRESSION IN THE LESION OF AORTIC ANEURYSMS
Authors: Pan Jing‐Wei , Wei Meng , Yang Peng‐Yuan , Zheng Xing , Li Jing‐bo , Lu Zhi‐gang , Zhao Xian‐Xian , Wu Hong , Kang Hui , Rui Yao‐cheng
Published: June 2007

Our previous study showed that Nogo‐B was highly expressed in endothelial cells and downregulated in endothelial cells following induction by lysophatidycholine, which contirubted to atherosclerotic lesions. However, the role of Nogo‐B in the development of aortic aneurysms remains unclear.

In the present study, segments of thoracic aortic aneurysms (TAA) and adjacent normal thoracic aortic tissues (NTA) without aneurysmal changes were obtained from 31 patients undergoing graft surgery. The mRNA and protein expression levels of Nogo‐B were measured with semiquantitative reverse transcription–polymerase chain reaction, western blotting and immunohistochemistry.

The results demonstrate that Nogo‐B mRNA expression levels in TAA lesions decreased to 45% compared with levels in NTA lesions and that protein levels in TAA decreased to 35%. Tissue Nogo immunohistochemical staining in aortic specimens suggested the involvement of Nogo in neovascularization and smooth muscle cell proliferation. The weaker brown staining of endothelial cells in TAA lesions suggested the lower expression of Nogo‐B in TAA lesions.

These results demonstrate that Nogo‐B mRNA and protein expression are downregulated in TAA lesions. It is concluded that the reduction of Nogo‐B protein expression in TAA lesions is closely correlated to the formation of aneurysm and that Nogo‐B may play a protective role in the pathological process of aneurysms.
RALOXIFENE, TAMOXIFEN AND VASCULAR TONE
Authors: Leung Fung Ping , Tsang Suk Ying , Wong Chi Ming , Yung Lai Ming , Chan Yau Chi , Leung Hok Sum , Yao Xiaoqiang , Huang Yu
Published: June 2007

Oestrogen deficiency causes progressive reduction in endothelial function. Despite the benefits of hormone‐replacement therapy (HRT) evident in earlier epidemiological studies, recent randomized trials of HRT for the prevention of heart disease found no overall benefit. Instead, HRT users had higher incidences of stroke and heart attack. Most women discontinue HRT because of its many side‐effects and/or the increased risk of breast and uterine cancer. This has contributed to the development of selective oestrogen receptor modulators (SERMs), such as tamoxifen and raloxifene, as alternative oestrogenic agents.

A SERM is a molecule that binds with high affinity to oestrogen receptors but has tissue‐specific effects distinct from oestrogen, acting as an oestrogen agonist in some tissues and as an antagonist in others. Clinical and animal studies suggest multiple cardiovascular effects of SERMs. For example, raloxifene lowers serum levels of cholesterol and homocysteine, attenuates oxidation of low‐density lipoprotein, inhibits endothelial–leucocyte interaction, improves endothelial function and reduces vascular smooth muscle tone.

Available evidence suggests that raloxifene and tamoxifen are capable of acting directly on both endothelial cells and the underlying vascular smooth muscle cells and cause a multitude of favourable modifications of the vascular wall, which jointly contribute to improved local blood flow. The outcome of the Raloxifene Use for the Heart (RUTH) trial will determine whether raloxifene, currently approved for the treatment of post‐menopausal osteoporosis, could substitute for HRT in alleviating cardiovascular symptoms in post‐menopausal women.
Invertebrate pests of canola and their management in Australia: a review
Authors: Gu Hainan , Fitt Gary P , Baker Geoff H
Published: June 2007

Abstract In Australia, canola is subject to attack by at least 30 species of invertebrate pests, although the composition of this pest complex can vary between regions. Mites (e.g. the redlegged earth miteHalotydeus destructorand the blue oat mitesPenthaleusspp.), lucerne flea (Sminthurus viridis) and false wireworms (e.g. the grey false wirewormIsopteron punctatissimusand the bronzed field beetleAdelium brevicorne) are the major pests threatening the seedling establishment, whereas aphids (the cabbage aphidBrevicoryne brassicae, the turnip aphidLipaphis erysimiand the green peach aphidMyzus persicae), the native budworm (Helicoverpa punctigera), the diamondback moth (Plutella xylostella) and the Rutherglen bug (Nysius vinitor) can cause irregular and unpredictable damage to the flowering and podding plants. Current tactics of pest management for canola rely largely on the use of synthetic pesticides, but this single‐technology approach is likely to incur negative effects on natural enemies and the risk of pest resistance. Thus, the sustainable production of canola requires integrated pest management (IPM) strategies, in which cultural control, crop resistance and biological control are used as important components, with chemical inputs applied only when absolutely needed to restrict pests from reaching economically damaging densities. Such IPM strategies should be built around a fundamental understanding of pest ecology at both regional and local farm levels and the integration of renewable technologies. Therefore, future research efforts need to be focused on the canola‐cropping system, with a particular emphasis on the impact of pest species, natural enemies of the pests, varietal resistance to pests and the spatial ecology of pest species.
Taxonomy and biology of two new species of gall midge (Diptera: Cecidomyiidae) infesting Sarcocornia quinqueflora (Chenopodiaceae) in Australian salt marshes
Authors: Veenstra‐Quah Anneke A , Milne Josephine , Kolesik Peter
Published: June 2007

Abstract  Two new species of gall midge associated with two distinct galls on the succulent creeping shrub Sarcocornia quinqueflora are described from salt marshes in south‐eastern Australia. The infestations caused by the new species hinder the growth of S. quinqueflora, the seeds of which are the major food of the critically endangered orange‐bellied parrot Neophema chrysogaster. Asphondylia floriformis sp. n. Veenstra‐Quah & Kolesik transforms leaf segments into flower‐like galls, whereas Asphondylia sarcocorniae sp. n. Veenstra‐Quah & Kolesik produces simple swellings on branches. Both galls have fungal mycelium growing in the apoplast of the gall tissue and lining the inner surface of the larval chamber where it is presumably grazed by the larva. Descriptions of the larvae, pupae, males, females and the geographical distribution of the two gall midges in south‐eastern Australia are given.
Ammonia‐oxidizing bacterial community composition in estuarine and oceanic environments assessed using a functional gene microarray
Authors: Ward Bess B. , Eveillard Damien , Kirshtein Julie D. , Nelson Joshua D. , Voytek Mary A. , Jackson George A.
Published: June 2007

The relationship between environmental factors and functional gene diversity of ammonia‐oxidizing bacteria (AOB) was investigated across a transect from the freshwater portions of the Chesapeake Bay and Choptank River out into the Sargasso Sea. Oligonucleotide probes (70‐bp) designed to represent the diversity of ammonia monooxygenase (amoA) genes from Chesapeake Bay clone libraries and cultivated AOB were used to construct a glass slide microarray. Hybridization patterns among the probes in 14 samples along the transect showed clear variations in amoA community composition. Probes representing uncultivated members of the Nitrosospira‐like AOB dominated the probe signal, especially in the more marine samples. Of the cultivated species, only Nitrosospira briensis was detected at appreciable levels. Discrimination analysis of hybridization signals detected two guilds. Guild 1 was dominated by the marine Nitrosospira‐like probe signal, and Guild 2′s largest contribution was from upper bay (freshwater) sediment probes. Principal components analysis showed that Guild 1 was positively correlated with salinity, temperature and chlorophyll a concentration, while Guild 2 was positively correlated with concentrations of oxygen, dissolved organic carbon, and particulate nitrogen and carbon, suggesting that different amoA sequences represent organisms that occupy different ecological niches within the estuarine/marine environment. The trend from most diversity of AOB in the upper estuary towards dominance of a single type in the polyhaline region of the Bay is consistent with the declining importance of AOB with increasing salinity, and with the idea that AO‐Archaea are the more important ammonia oxidizers in the ocean.
Dynamics of the hydrocarbon‐degrading Cycloclasticus bacteria during mesocosm‐simulated oil spills
Authors: Teira Eva , Lekunberri Itziar , Gasol Josep M. , Nieto‐Cid Mar , Álvarez‐Salgado Xosé Antón , Figueiras Francisco G.
Published: June 2007

We used catalysed reported deposition – fluorescence in situ hybridization (CARD‐FISH) to analyse changes in the abundance of the bacterial groups Alphaproteobacteria, Gammaproteobacteria and Bacteroidetes, and of hydrocarbon‐degrading Cycloclasticus bacteria in mesocosms that had received polycyclic aromatic hydrocarbons (PAHs) additions. The effects of PAHs were assessed under four contrasting hydrographic conditions in the coastal upwelling system of the Rías Baixas: winter mixing, spring bloom, summer stratification and autumn upwelling. We used realistic additions of water soluble PAHs (approximately 20–30 μg l−1 equivalent of chrysene), but during the winter period we also investigated the effect of higher PAHs concentrations (10–80 μg l−1 chrysene) on the bacterial community using microcosms. The most significant change observed was a significant reduction (68 ± 5%) in the relative abundance of Alphaproteobacteria. The magnitude of the response of Cycloclasticus bacteria (positive with probe CYPU829) to PAHs additions varied depending on the initial environmental conditions, and on the initial concentration of added PAHs. Our results clearly show that bacteria of the Cycloclasticus group play a major role in low molecular weight PAHs biodegradation in this planktonic ecosystem. Their response was stronger in colder waters, when their background abundance was also higher. During the warm periods, the response of Cycloclasticus was limited, possibly due to both, a lower bioavailability of PAHs caused by abiotic factors (solar radiation, temperature), and by inorganic nutrient limitation of bacterial growth.
PROPERTIES OF OPTION PRICES IN MODELS WITH JUMPS
Authors: Ekström Erik , Tysk Johan
Published: June 2007

We study convexity and monotonicity properties of option prices in a model with jumps using the fact that these prices satisfy certain parabolic integro–differential equations. Conditions are provided under which preservation of convexity holds, i.e., under which the value, calculated under a chosen martingale measure, of an option with a convex contract function is convex as a function of the underlying stock price. The preservation of convexity is then used to derive monotonicity properties of the option value with respect to the different parameters of the model, such as the volatility, the jump size, and the jump intensity.
THE GERMAN SERVICE GAP OR: RE‐ORGANISING THE MANUFACTURING––SERVICES PUZZLE
Authors: Preissl Brigitte
Published: June 2007

Two phenomena make the distinction between services and manufacturing obsolete: the tertiarization of manufacturing and the introduction of information technologies in service industries. Competitiveness of manufacturing firms increasingly depends on the quality of service inputs and on packages of goods and services. Information and communication technologies introduce ‘industrial’ processes of production in service industries. Hence, it does not make sense any more to use categories such as ‘services’ or ‘manufacturing’. Instead, it would be more meaningful to group economic activities according to input configurations. This paper will discuss these issues in the context of the supposed German ‘service gap’.
THE STATISTICAL MEASUREMENT OF SERVICES: RECENT ACHIEVEMENTS AND REMAINING CHALLENGES
Authors: Cave William , Giovannini Enrico
Published: June 2007

Services are increasingly important in the output of modern economies and are increasingly traded internationally. These patterns are observed in the generality of both ‘developed’ and ‘developing’ economies. This paper discusses the policy needs to understand the impact of services on the performance of modern economies, some measurement problems, and actions undertaken by international organisations to address these issues. It concludes that development work on services prices and volumes is fundamental to measurement of growth, and there is a need to engage more countries in the development of their service statistics with improved co‐ordination of technical assistance.
Histological Classif ication of Gastritis and Helicobacter pylori Infection: An Agreement at Last?
Authors: Dixon Michael F. , Genta Robert M. , Yardley John H. , Correa Pelayo , For The International Workshop on the Histopathology of Gast
Published: June 2007

An international workshop has assessed and revised the Sydney System for the reporting of gastritis. Much of the original approach was retained including division into acute, chronic and special forms, and grading of chronic inflammation, polymorph activity, atrophy, intestinal metaplasia and H. pylori density into mild, moderate and marked categories. Visual analog scales have been introduced as a simple guide to grading. The four biopsy sites have been changed to optimize detection of H. pylori, and supplemented by a fifth biopsy from the incisura angularis, the site which is most likely to yield premalignant changes. Chronic gastritis is classified into non‐atrophic and atrophic forms with the latter divided into autoimmune (diffuse corpus atrophy) and multifocal. Histological reporting of gastritis should take into account the topographical pattern (antral or corpuspredominant), and the final diagnostic term should ideally combine morphology and etiology to maximize the clinical value of gastric biopsy diagnosis.
Urea Breath Tests for the Detection of Helicobacter pylori Infection
Authors: Bazzoli Franco , Zagari Maurizio , Fossi Stefania , Pozzato Paolo , Ricciardiello Luigi , Mwangemi Constance , Roda Aldo , Roda Enrico
Published: June 2007

Background.

Helicobacter pylori is recognized as an important human pathogen. The urea breath test, using either 13C or 14C, provides a noninvasive diagnostic method for the detection of active H. pylori infection.

Methods.

We review the data regarding the utility of the urea breath test in the diagnosis and follow‐up of patients with suspected H. pylori infection.

Results.

Following its ingestion, labeled urea is hydrolyzed by H. pylori urease, producing ammonia and labeled CO2, which is absorbed and can be detected in expired breath. The urea breath test provides a semiquantitative assessment of the load of H. pylori and overcomes the problem of the sampling error due to the patchy distribution of the infection. 13C‐urea breath test has an advantage over the 14C version, because the 13C isotope is a nonradioactive natural isotope; therefore, a user’s license is unnecessary, making simple the handling and mailing of samples. The 13C‐urea breath test is preferred in children and expectant mothers.

Conclusion.

The high sensitivity, and specificity of the 13C‐urea breath test are such that it can be considered a clinical gold standard against which other diagnostic methods can be validated. This test can be used as the sole method for evaluating the effectiveness of treatment of H. pylori infection.
Widespread Eradication of Helicobacter pylori: A Debate
Authors: Stanghellini Vincenzo , Cogliandro Laura , Cogliandro Rosanna , Giorgio Roberto De , Corinaldesi Roberto
Published: June 2007

Background.

Helicobacter pylori eradication is recommended currently only in peptic ulcer patients. The accumulating evidence of a possible pathogenetic role of the germ in other pathological conditions, such as mucosa‐associated lymphoid tissue lymphomas and (possibly) also functional dyspepsia and gastric cancer, creates increasing pressure in favor of an expansion of such indication. However, at present, cultural and practical considerations should discourage widespread screening and eradication programs.

Methods.

The basis for our study is a critical review of the literature.

Results.

The lack of a sound pathophysiological basis linking H. pylori infection to both dyspeptic symptom perception and gastric cancer risk sharply contrasts with the numerical and clinical relevance of these pathological conditions. Screening tests are not sufficiently cheap, easy, and reliable to be applicable on a large scale. Also, eradication therapies may provide suboptimal therapeutic effects and excessive side effects if applied by physicians who are not prepared culturally.

Conclusions.

Improvement of pathophysiological, diagnostic, and therapeutic knowledge must be achieved before eradication programs can be proposed on a large scale.
Identifying Persons at Risk for Gastric Cancer?
Authors: Miehlke Stephan , Bayerdörffer Ekkehard , Meining Alexander , Stolte Manfred , Thinsp; Peter Malfertheiner
Published: June 2007

Background.

Although considerable evidence suggests thatHelicobacter pyloriinfection plays a crucial role in the pathogenesis of gastric carcinoma, a striking difference exists between the number of infected individuals and the proportion of those developing gastric carcinoma. The purpose of this article is to review the available evidence supporting the existence of identifiable risk factors for the development of gastric carcinoma.

Methods.

We performed a critical review of the pertinent literature, which forms the basis for this study.

Results.

In terms of treatment strategies for prevention of gastric carcinoma, cure ofH. pyloriinfection in all infected patients seems unfeasible, mainly for economic reasons. However, the final and definite step to prove that infection withH. pyloriis a preneoplastic condition for the development of gastric cancer would be the observation that cure of the infection leads to a significant reduction in gastric cancer incidence rates in comparison with an untreated population. Therefore, in 1997 a multicenter preventive interventional study on gastric carcinoma will be started in Germany. The target group in this study includes patients with a specific pattern ofH. pylorigastritis who will be summarized by a “gastric cancer risk index.”

Conclusions.

It is hoped that long‐term follow‐up of these patients will reveal whether preventive treatment ofH. pyloriinfection is capable of reducing the risk for development of gastric cancer.
A Study of Fruit–Frugivore Interactions in Two Species of Durian (Durio, Bombacaceae) in Sabah, Malaysia
Authors: Nakashima Yoshihiro , Lagan Peter , Kitayama Kanehiro
Published: June 2007

We determined the fruit predators and seed dispersers of two species of durian (Durio, Bombacaceae), D. graveolens and D. zibethinus, which have contrasting aril color and timing of dehiscence by observing fruiting trees in Deramakot forest reserve. In our observations in the wild, both species were extensively predated by orangutans before fruits matured. Durio graveolens was dispersed by black hornbills and D. zibethinus was dispersed by long‐tailed macaques.
Characterizing Hydraulic Conductivity with the Direct‐Push Permeameter
Authors: Butler James J. , Dietrich Peter , Wittig Volker , Christy Tom
Published: June 2007

The direct‐push permeameter (DPP) is a promising approach for obtaining high‐resolution information about vertical variations in hydraulic conductivity (K) in shallow unconsolidated settings. This small‐diameter tool, which consists of a short screened section with a pair of transducers inset in the tool near the screen, is pushed into the subsurface to a depth at which a K estimate is desired. A short hydraulic test is then performed by injecting water through the screen at a constant rate (less than 4 L/min) while pressure changes are monitored at the transducer locations. Hydraulic conductivity is calculated using the injection rate and the pressure changes in simple expressions based on Darcy’s Law. In units of moderate or higher hydraulic conductivity (more than 1 m/d), testing at a single level can be completed within 10 to 15 min. Two major advantages of the method are its speed and the insensitivity of the K estimates to the zone of compaction created by tool advancement. The potential of the approach has been assessed at two extensively studied sites in the United States and Germany over a K range commonly faced in practical field investigations (0.02 to 500 m/d). The results of this assessment demonstrate that the DPP can provide high‐resolution K estimates that are in good agreement with estimates obtained through other means.
Use of the Transtheoretical Model to Predict Stages of Smoking Cessation in Korean Adolescents
Authors: Ham Ok Kyung , Lee Young Ja
Published: June 2007

Background:  Smoking is popular among Korean male high school adolescents, with the prevalence of 20.7% differing markedly with the type of school, being 16.3% and 27.6% in academic and vocational technical high schools, respectively. The purpose of this study was to identify significant variables that predict stages of smoking cessation among Korean high school students using the transtheoretical model (TTM), in order to provide an empirical basis for developing smoking cessation programs.

Methods:  Cross‐sectional data were collected in April and May 2004 from 300 male students at 3 vocational technical high schools in Korean metropolitan areas. The survey variables comprised decisional balance, self‐efficacy, stages and processes of change, nicotine dependence, and use of smoking cessation aids.

Results:  Current and former smokers comprised 26.3% and 22.7% of the cohort, respectively, of which 71.4% had experienced smoking cessation at least once and 55.1% utilized smoking cessation aids to help stop smoking. Nicotine‐free tobacco and nicotine gum were the most common smoking cessation aids. Decisional balance, use of behavioral processes, and higher self‐efficacy were significant in explaining stages of smoking cessation after controlling for nicotine dependence.

Conclusions:  The study results suggest that smoking cessation programs developed based on the TTM may help adolescents to progress through stages, with it being important to include information regarding the use of smoking cessation aids.
IR Laser and Heat‐induced Changes in Annulus Fibrosus Collagen Structure
Authors: Ignatieva Natalia Yu. , Zakharkina Olga L. , Andreeva Irina V. , Sobol Emil N. , Kamensky Vladislav A. , Myakov Alexey V. , Averkiev Sergey V. , Lunin Valery V.
Published: June 2007

The purpose of this study was to characterize essential changes in the structure of annulus fibrosus (AF) after hydrothermal and infrared (IR) laser treatment and to correlate these results with alterations in tissue state. Polarization‐sensitive optical coherence tomography imaging was used to measure collagen birefringence in AF. Differential scanning calorimetry was used as a complementary technique, providing detailed information on thermodynamic processes in the tissue. Birefringence, peak of the denaturation endotherm, and the enthalpy of denaturation (ΔHm) were determined before and after hydrothermal heat treatment (85°C for 15 min) and non‐ablative Er:glass fiber laser exposures on AF in the whole disk (vertebrae‐disk–vertebrae complex). Our data have demonstrated quantitative differences between results of laser and hydrothermal heating. Birefringence did not disappear and ΔHm did not change after treatment in the water bath, but loss of birefringence and a decrease in the enthalpy did occur after laser exposure. These results could be explained by the photomechanical effect of laser irradiation. We suggest that thermo‐mechanical stress played a dominant role in the disruption of the collagen network of AF under non‐homogeneous laser heating.
SURFACE ENERGIES IN NONCONVEX DISCRETE SYSTEMS
Authors: BRAIDES ANDREA , CICALESE MARCO
Published: June 2007

We analyze the variational limit of one-dimensional next-to-nearest neighbours (NNN) discrete systems as the lattice size tends to zero when the energy densities are of multiwell or Lennard–Jones type. Properly scaling the energies, we study several phenomena as the formation of boundary layers and phase transitions. We also study the presence of local patterns and of anti-phase transitions in the asymptotic behaviour of the ground states of NNN model subject to Dirichlet boundary conditions. We use this information to prove a localization of fracture result in the case of Lennard–Jones type potentials.
GLOBAL WEAK SOLUTIONS FOR A VLASOV–FOKKER–PLANCK/NAVIER–STOKES SYSTEM OF EQUATIONS
Authors: MELLET A. , VASSEUR A.
Published: June 2007

We establish the existence of a weak solutions for a coupled system of kinetic and fluid equations. More precisely, we consider a Vlasov–Fokker–Planck equation coupled to compressible Navier–Stokes equation via a drag force. The fluid is assumed to be barotropic with γ-pressure law (γ > 3/2). The existence of weak solutions is proved in a bounded domain of ℝ3 with homogeneous Dirichlet conditions on the fluid velocity field and Dirichlet or reflection boundary conditions on the kinetic distribution function.
COMPARISON BETWEEN DISCRETE AND PACKET WAVELET TRANSFORM ANALYSES IN THE STUDY OF HEARTBEAT CARDIAC SOUNDS
Authors: DEBBAL S. M. , BEREKSI-REGUIG F.
Published: June 2007

This work investigates the study of heartbeat cardiac sounds through time–frequency analysis by using the wavelet transform method. Heart sounds can be utilized more efficiently by medical doctors when they are displayed visually rather through a conventional stethoscope. Heart sounds provide clinicians with valuable diagnostic and prognostic information. Although heart sound analysis by auscultation is convenient as a clinical tool, heart sound signals are so complex and nonstationary that they are very difficult to analyze in the time or frequency domain. We have studied the extraction of features from heart sounds in the time–frequency (TF) domain for the recognition of heart sounds through TF analysis. The application of wavelet transform (WT) for heart sounds is thus described. The performances of discrete wavelet transform (DWT) and wavelet packet transform (WP) are discussed in this paper. After these transformations, we can compare normal and abnormal heart sounds to verify the clinical usefulness of our extraction methods for the recognition of heart sounds.
FROM PEIERLS BRACKETS TO A GENERALIZED MOYAL BRACKET FOR TYPE-I GAUGE THEORIES
Authors: ESPOSITO GIAMPIERO , STORNAIOLO COSIMO
Published: June 2007

In the space-of-histories approach to gauge fields and their quantization, the Maxwell, Yang–Mills and gravitational field are well known to share the property of being type-I theories, i.e. Lie brackets of the vector fields which leave the action functional invariant are linear combinations of such vector fields, with coefficients of linear combination given by structure constants. The corresponding gauge-field operator in the functional integral for the in-out amplitude is an invertible second-order differential operator. For such an operator, we consider advanced and retarded Green functions giving rise to a Peierls bracket among group-invariant functionals. Our Peierls bracket is a Poisson bracket on the space of all group-invariant functionals in two cases only: either the gauge-fixing is arbitrary but the gauge fields lie on the dynamical sub-space; or the gauge-fixing is a linear functional of gauge fields, which are generic points of the space of histories. In both cases, the resulting Peierls bracket is proved to be gauge-invariant by exploiting the manifestly covariant formalism. Moreover, on quantization, a gauge-invariant Moyal bracket is defined that reduces to iħ times the Peierls bracket to lowest order in ħ.
MORE ON THE ISOMORPHISM SU(2) ⊗ SU(2) ≅ SO(4)
Authors: FUJII KAZUYUKI , OIKE HIROSHI , SUZUKI TATSUO
Published: June 2007

In this paper, we revisit the isomorphism SU(2) ⊗ SU(2) ≅ SO(4) to apply to some subjects in Quantum Computation and Mathematical Physics.

The unitary matrix Q by Makhlin giving the isomorphism as an adjoint action is studied and generalized from a different point of view. Some problems are also presented.

In particular, the homogeneous manifold SU(2n)/SO(2n) which characterizes entanglements in the case of n = 2 is studied, and a clear-cut calculation of the universal Yang–Mills action in (hep-th/0602204) is given for the abelian case.
THE INFLUENCE OF INTERNATIONAL TRADE ON THE ENVIRONMENT
Authors: RAMRATTAN LALL , SZENBERG MICHAEL
Published: June 2007

This paper builds an econometric model that attempts to explain the effect of global trade on the environment from data provided by the Global Trade Analysis Project (GTAP) at Purdue University. We estimated stable parameters for econometric models to forecast the impact of doubling carbon dioxide (2 × CO2) levels in the atmosphere. Robustness is checked against the Specific Factor Model in trade theory. The overall and zonal predictions for the lower and higher latitudes and the Northern and Southern Hemispheres are compared with the norms. The estimates of the model are also used as inputs into several computable general equilibrium (CGE) models to explore regional welfare impacts by climate change scenarios. The model's prediction comes within range of the norms and therefore, should be an important addition to the stock of pedagogic tools explaining the relationship between trade and the environment.
Increased Aβ Production Leads to Intracellular Accumulation of Aβ in Flotillin-1-Positive Endosomes
Authors: Rajendran Lawrence , Knobloch Marlen , Geiger Kathrin D. , Dienel Stephanie , Nitsch Roger , Simons Kai , Konietzko Uwe
Published: June 2007

Extracellular accumulation of Aβ in β-amyloid plaques is thought to be associated with the neurodegeneration observed in Alzheimer’s disease (AD) patients, although a lack of correlation with cognitive decline raised doubts on this hypothesis. In different transgenic mouse models Aβ accumulates inside the cells and mice develop behavioral deficits well before visible extracellular β-amyloid accumulation. Here we show that intracellular Aβ accumulates in flotillin-1 positive endocytic vesicles. We also demonstrate that flotillin-1 is not only associated with intracellular Aβ in transgenic mice but also with extracellular β-amyloid plaques in AD patient brain sections.
Caenorhabditis elegans as a Model System for Parkinson’s Disease
Authors: Schmidt Enrico , Seifert Mark , Baumeister Ralf
Published: June 2007

Parkinson’s disease (PD) is one of the most common age-related neurodegenerative diseases that is characterized by selective loss of dopaminergic neurons. Despite recent findings from mammalian model systems, molecular mechanisms of the pathophysiology are poorly understood. Given the high conservation of molecular pathways from invertebrates to mammalians, combined with technical advantages, such as high-throughput approaches, Caenorhabditis elegans represents a powerful system for the identification of factors involved in neurodegeneration. In this review we describe that C. elegans can be used to advance our understanding of the genetic mechanisms implicated in these disorders.
New Insights on Saccus vasculosus Evolution: A Developmental and Immunohistochemical Study in Elasmobranchs
Authors: Sueiro Catalina , Carrera Iván , Ferreiro Susana , Molist Pilar , Adrio Fátima , Anadón Ramón , Rodríguez-Moldes Isabel
Published: June 2007

The saccus vasculosus (SV) is a circumventricular organ of the hypothalamus of many jawed fishes whose functions have not yet been clarified. It is a vascularized neuroepithelium that consists of coronet cells, cerebrospinal fluid-contacting (CSF-c) neurons and supporting cells. To assess the organization, development and evolution of the SV, the expression of glial fibrillary acidic protein (GFAP) and the neuronal markers γ-aminobutyric acid (GABA), glutamic acid decarboxylase (GAD; the GABA synthesizing enzyme), neuropeptide Y (NPY), neurophysin II (NPH), tyrosine hydroxylase (TH; the rate-limiting catecholamine-synthesizing enzyme) and serotonin (5-HT), were investigated by immunohistochemistry in developing and adult sharks. Coronet cells showed GFAP immunoreactivity from embryos at stage 31 to adults, indicating a glial nature. GABAergic CSF-c neurons were evidenced just when the primordium of the SV becomes detectable (at stage 29). Double immunolabeling revealed colocalization of NPY and GAD in these cells. Some CSF-c cells showed TH immunoreactivity in postembryonic stages. Saccofugal GABAergic fibers formed a defined SV tract from the stage 30 and scattered neurosecretory (NPH-immunoreactive) and monoaminergic (5-HT- and TH-immunoreactive) saccopetal fibers were first detected at stages 31 and 32, respectively. The early differentiation of GABAergic neurons and the presence of a conspicuous GABAergic saccofugal system are shared by elasmobranch and teleosts (trout), suggesting that GABA plays a key function in the SV circuitry. Monoaminergic structures have not been reported in the SV of bony fishes, and were probably acquired secondarily in sharks. The existence of saccopetal monoaminergic and neurosecretory fibers reveals reciprocal connections between the SV and hypothalamic structures which have not been previously detected in teleosts.
Implications of Neocytolysis for Optimal Management of Anaemia in Chronic Kidney Disease
Authors: Alfrey Clarence P. , Fishbane Steven
Published: June 2007

Erythropoietin is the major hormone regulator of erythrocyte production promoting the survival, as well as the differentiation and maturation, of erythroid progenitor cells. In addition to these well-characterized effects, it appears that an erythropoietin-responsive non-erythroid mechanism also mediates the selective destruction of young circulating erythrocytes (neocytes) when red cell mass becomes excessive – a process termed ‘neocytolysis’. Endothelial cells appear to respond to a rapid decrease in circulating levels of erythropoietin by secreting cytokines (including TGF-α), which signal reticuloendothelial phagocytes to destroy neocytes. The result is a more rapid decrease in red cell mass than can be explained by natural erythrocyte senescence alone. The current pharmacologic approach to treatment of anaemia in chronic kidney disease may cause neocytolysis and could keep therapy from reaching its full potential. Understanding neocytolysis and its relationship to fluctuating serum erythropoietin levels might help to better understand optimal treatment with erythropoietic agents.