bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cell‐specific localization of Na+ in roots of durum wheat and possible control points for salt exclusion
Authors: LÄUCHLI ANDRÉ , JAMES RICHARD A. , HUANG CHENG X. , McCULLY MARGARET , MUNNS RANA 
Published: August 2008

ABSTRACTSodium exclusion from leaves is an important mechanism for salt tolerance in durum wheat. To characterize possible control points for Na+ exclusion, quantitative cryo‐analytical scanning electron microscopy was used to determine cell‐specific ion profiles across roots of two durum wheat genotypes with contrasting rates of Na+ transport from root to shoot grown in 50 mm NaCl. The Na+ concentration in Line 149 (low transport genotype) declined across the cortex, being highest in the epidermal and sub‐epidermal cells (48 mm) and lowest in the inner cortical cells (22 mm). Na+ was high in the pericycle (85 mm) and low in the xylem parenchyma (34 mm). The Na+ profile in Tamaroi (high transport genotype) had a similar trend but with a high concentration (130 mm) in the xylem parenchyma. The K+ profiles were generally inverse to those of Na+. Chloride was only detected in the epidermis. These data suggest that the epidermal and cortical cells removed most of the Na+ and Cl‐ from the transpiration stream before it reached the endodermis, and that the endodermis is not the control point for salt uptake by the plant. The pericycle as well as the xylem parenchyma may be important in the control of net Na+ loading of the xylem.
Plastid genomes in a regenerating tobacco shoot derive from a small number of copies selected through a stochastic process
Authors: Lutz Kerry Ann , Maliga Pal 
Published: August 2008

SummaryThe plastid genome (ptDNA) of higher plants is highly polyploid, and the 1000–10 000 copies are compartmentalized with up to approximately 100 plastids per cell. The problem we address here is whether or not a newly arising genome can be established in a developing tobacco shoot, and be transmitted to the seed progeny. We tested this by generating two unequal ptDNA populations in a cultured tobacco cell. The parental tobacco plants in this study have an aurea (yellowish–golden) leaf color caused by the presence of a barau gene in the ptDNA. In addition, the ptDNA carries an aadA gene flanked with the phiC31 phage site‐specific recombinase (Int) attP/attB target sites. The genetically distinct ptDNA copies were obtained by Int, which either excised only the aadA marker gene (i.e. did not affect the aurea phenotype) or triggered the deletion of both the aadA and barau transgenes, and thereby restored the green color. The ptDNA determining green plastids represented only a small fraction of the population and was not seen in a transient excision assay, and yet three out of the 53 regenerated shoots carried green plastids in all developmental layers. The remaining 49 Int‐expressing plants had either exclusively aurea (24) or variegated (25) leaves with aurea and green sectors. The formation of homoplastomic green shoots with the minor green ptDNA in all developmental layers suggests that the ptDNA population in a regenerating shoot apical meristem derives from a small number of copies selected through a stochastic process.
Interaction of the K+‐channel KAT1 with the coat protein complex II coat component Sec24 depends on a di‐acidic endoplasmic reticulum export motif
Authors: Sieben Christian , Mikosch Melanie , Brandizzi Federica , Homann Ulrike 
Published: August 2008

SummaryThe correct functioning of ion channels depends not only on the control of their activity but also on the regulation of the number of channels in the membrane. For example, it has been proposed that the density of the plant K+‐channel KAT1 may be adjusted by controlling its export from its site of synthesis, the endoplasmic reticulum (ER). Efficient transport of the channel to the plasma membrane was found to depend on a di‐acidic ER export signal in the C‐terminus of the protein. Studies in yeast and mammals indicate that di‐acidic ER export motifs are essential for enrichment of proteins into ER‐derived coat protein complex II (COPII) vesicles and are recognized by Sec24 a component of the COPII coat. To investigate whether similar mechanisms also exist in plants we have analysed the interaction of KAT1 with Sec24 in vivo using fluorescence resonance energy transfer (FRET) measurements in Vicia faba guard cells. These measurements revealed a FRET signal between KAT1 and Sec24 fused to the cyan fluorescent protein and the yellow fluorescent protein, respectively, indicating an interaction between KAT1 and Sec24. The FRET signal only occurred in the perinuclear region of the ER and was dependent on the di‐acidic ER export motif of KAT1. Together, the results point to a highly conserved mechanism for ER export of KAT1 whereby the channel is recruited into COPII vesicles via binding of the di‐acidic motif to Sec24.
Impact of a new invasive ctenophore (Mnemiopsis leidyi) on the zooplankton community of the Southern Caspian sea
Authors: Roohi Abolghasem , Yasin Zulfigar , Kideys Ahmet E. , Hwai Aileen Tan Shau , Khanari Ali Ganjian , Eker‐Develi Elif 
Published: August 2008

AbstractThe invasive ctenophore Mnemiopsis leidyi (Agassiz), which was transported from the Black Sea into the Caspian Sea at the end of the 1990s, has negatively affected the ecosystem of the Caspian Sea. Zooplankton abundance, biomass and species composition were evaluated on the Iranian coast of the Caspian Sea during 2001–2006. A total of 18 merozooplankton (13 species composed of larvae of benthic animals) and holozooplankton (four Copepoda and one Cladocera) species were identified. The total number of zooplankton species found here was 50% less than in a previous investigation performed in the same region in 1996 before the introduction of Mnemiopsis leidyi into the Caspian Sea. Cladocera species seemed to be highly affected by the invasion of Mnemiopsis leidyi; only one species, Podon polyphemoides, remained in the study area, whereas 24 Cladocera species were found in the study carried out in 1996. Whereas among the Copepoda Eurytemora minor, Eurytemora grimmi, Calanipeda aquae dulcis and Acartia tonsa that were abundant before the Mnemiopsis leidyi invasion, only A. tonsa (copepodites and adults) dominated the inshore and offshore waters after the invasion. The maximum in zooplankton abundance (22,088 ± 24,840 ind·m−3) and biomass (64.1 ± 56.8 mg·m−3) were recorded in December 2001 and August 2004, respectively. The annual mean zooplankton abundance during 2001–2006 was in the range of 3361–8940 ind·m−3; this was two‐ to five‐fold less than the zooplankton abundance in 1996. During 2001–2006, the highest abundance and biomass of Mnemiopsis leidyi were observed during summer‐autumn months coincident with warm temperatures and generally when the abundance of other zooplankton organisms was low.
Dietary fibre and the gut microbiota
Authors: Scott K. P. , Duncan S. H. , Flint H. J. 
Published: August 2008

Summary The complex human colonic microbiota plays a key role in gut health, and both the composition and metabolism of the gut microbiota are strongly diet related. Controlled dietary intake studies in obese individuals demonstrated that consumption of low‐carbohydrate diets results in low faecal butyrate concentrations together with a low abundance of the major butyrate‐producing bacteria,Roseburiaspp. andEubacterium rectalegroup.Resistant dietary carbohydrates, including pre‐biotics, escape digestion in the upper gastrointestinal tract and are fermented to short‐chain fatty acids (SCFAs) by bacteria in the colon. The main SCFAs formed are acetate, propionate and butyrate. Model colonic fermentor systems employed to determine which bacterial groups utilise specific substrates indicated that the bacterial composition and production of SCFAs is substrate dependent. The bacterial colonisers of specific substrates were identified using 16S rRNA sequence analysis. Sequences recovered from bran were most closely related toRoseburiaspp.,E. rectaleandClostridium hathewayi, while on resistant starch, sequences were most closely related toRuminococcus bromiiandBifidobacterium adolescentis.Differing intakes of dietary carbohydrate also impact on other factors in the colon such as transit and pH. In continuous fermentor systems, a slightly acidic pH (5.5) representative of the proximal colon gave fourfold higher butyrate concentrations than at the higher pH of 6.5, which is more representative of the distal colon.Bacteroidetesdominated the fermentor at pH 6.5, while the major butyrate‐producing bacterial groups competed more effectively for carbohydrate substrates when the pH was mildly acidic (5.5). Inin vitrostudies in which pH values were even lower, pH 5.2, lactate and acetate accumulated. In contrast, lactate was not detected at pH 6.4 although stable isotope studies revealed that lactate was actively produced. Lactate accumulation at low pH appears to be as a result of the loss of lactate‐utilising bacteria includingEubacterium hallii.It is clear that the composition of the colonic microbiota and the balance of its metabolic products is strongly influenced by diet and, in particular, by the intake of resistant carbohydrates and dietary fibre.
Valuing executive stock options: performance hurdles, early exercise and stochastic volatility
Authors: Brown Philip , Szimayer Alex 
Published: August 2008

AbstractAccounting standards require companies to assess the fair value of any stock options granted to executives and employees. We develop a model for accurately valuing executive and employee stock options, focusing on performance hurdles, early exercise and uncertain volatility. We apply the model in two case studies and show that properly computed fair values can be significantly lower than traditional Black–Scholes values. We then explore the implications for pay‐for‐performance sensitivity and the design of effective share‐based incentive schemes. We find that performance hurdles can require a much greater fraction of total compensation to be a fixed salary, if pre‐existing incentive levels are to be maintained.
Co‐speech gesture as input in verb learning
Authors: Goodrich Whitney , Hudson Kam Carla L. 
Published: August 2008

AbstractPeople gesture a great deal when speaking, and research has shown that listeners can interpret the information contained in gesture. The current research examines whether learners can also use co‐speech gesture to inform language learning. Specifically, we examine whether listeners can use information contained in an iconic gesture to assign meaning to a novel verb form. Two experiments demonstrate that adults and 2‐, 3‐, and 4‐year‐old children can infer the meaning of novel intransitive verbs from gestures when no other source of information is present. The findings support the idea that gesture might be a source of input available to language learners.
Amerindian Amazons: women, exchange, and the origins of society
Authors: Steverlynck Astrid 
Published: August 2008

The Amerindian myths of Amazon‐like women, widespread in lowland South America, refer to the primordial exchange of particular ritual objects between men and women:ciba, greenstones, flutes, axes. This primordial exchange represents the socially creative moment that led to the establishment of society and provides a general model for social relationships. The ritual exchange or circulation of these objects in other spheres involving male‐male relationships turns ordinary exchanges into socially creative exchanges by ritually re‐creating the exchange described in the myths. The myths shift the focus from male‐male relationships to female‐male relationships as the basis of society and provide a commentary on the significance of exchange and social relationships in lowland South America.RésuméLargement répandus dans les plaines d'Amérique du Sud, les mythes amérindiens évoquant des femmes comparables aux Amazones font référence à l'échange primordial d'objets rituels particuliers entre hommes et femmes :ciba, pierres vertes, flûtes, haches . . . Ces échanges primordiaux représentent le moment socialement créatif qui a débouché sur l'établissement de la société, et donnent un modèle général des relations sociales. L'échange ou la circulation rituels de ces objets dans d'autres sphères impliquant une relation d'homme à homme transforme ces transactions ordinaires en processus socialement créatifs en recréant rituellement l'échange décrit par les mythes. Il déplace l'accent des relations femmes‐hommes aux relations hommes‐hommes comme base de la société, et apporte un éclairage sur la signification des échanges et des relations sociales dans les plaines d'Amérique du Sud.
Corporate Real Estate Sale and Leaseback Effect: Empirical Evidence from Europe
Authors: Grönlund Tomi , Louko Antti , Vaihekoski Mika 
Published: August 2008

Abstract Corporate real estate disposals have increased in Europe during the past few years. In this research paper, we study market reactions of publicly traded European companies' real estate sale and leaseback announcements during 1998–2004. This study is one of the first ones to study the sale and leaseback impact on corporate value with a pan‐European data. We find that the sale and leaseback announcements have on average positive impact to firm's value which is in line with the previous studies. However, we also find that the positive effect is mainly caused by the deals with high transaction value to company market value ratio. Smaller transactions do not create on average any abnormal returns. Our results support the hypothesis that the positive sale and leaseback announcement effect is a consequence of revealed hidden value of the company's assets. Thus, sale and leaseback can also be seen as a mechanism for revealing the hidden value of company's assets to the market.
Trust in Financial Markets
Authors: Mayer Colin 
Published: August 2008

Abstract This paper examines contemporaneous and historical evidence on the structure of ownership and control of corporate sectors in developed countries to draw lessons for development of financial markets. It records the critical role that equity markets played in the ownership and financing of corporations at the beginning of the 20th century. It notes that this occurred in the absence of formal systems of regulation and that equity markets functioned on the basis of informal relationships of trust. These were sustained through local stock markets in the UK, banks in Germany, and business coordinators and family firms in Japan. The paper explores the concept of trust that is required to promote the development of financial markets.
Efficient Association Study Design Via Power‐Optimized Tag SNP Selection
Authors: Han B. , Kang H. M. , Seo M. S. , Zaitlen N. , Eskin E. 
Published: August 2008

SummaryDiscovering statistical correlation between causal genetic variation and clinical traits through association studies is an important method for identifying the genetic basis of human diseases. Since fully resequencing a cohort is prohibitively costly, genetic association studies take advantage of local correlation structure (or linkage disequilibrium) between single nucleotide polymorphisms (SNPs) by selecting a subset of SNPs to be genotyped (tag SNPs). While many current association studies are performed using commercially available high‐throughput genotyping products that define a set of tag SNPs, choosing tag SNPs remains an important problem for both custom follow‐up studies as well as designing the high‐throughput genotyping products themselves. The most widely used tag SNP selection method optimizes the correlation between SNPs (r2). However, tag SNPs chosen based on an r2 criterion do not necessarily maximize the statistical power of an association study. We propose a study design framework that chooses SNPs to maximize power and efficiently measures the power through empirical simulation. Empirical results based on the HapMap data show that our method gains considerable power over a widely used r2‐based method, or equivalently reduces the number of tag SNPs required to attain the desired power of a study. Our power‐optimized 100k whole genome tag set provides equivalent power to the Affymetrix 500k chip for the CEU population. For the design of custom follow‐up studies, our method provides up to twice the power increase using the same number of tag SNPs as r2‐based methods. Our method is publicly available via web server at http://design.cs.ucla.edu.
Value‐based labels for fresh beef: an overview of French consumer behaviour in a BSE crises context
Authors: Sans Pierre , De Fontguyon Guy , Giraud Georges 
Published: August 2008

AbstractIn the last decade, the French beef industry has been through two major health scares related to bovine spongiform encephalopathy. This paper describes and discusses changes in beef supply in France from the consumer's perspective. The authors review the initiatives implemented in each crisis and show that the immediate effects (slump in consumption), however spectacular, were not the most lasting effects. By contrast, responses from the industry and the authorities brought about a far‐reaching change in practices by requiring new instruments to be used (traceability). Yet the information conveyed by this innovation cannot readily be appropriated by consumers who are not conversant with the characteristics of beef production systems.
Neural plasticity and addiction: integrin‐linked kinase and cocaine behavioral sensitization
Authors: Chen Qiang , Xiong Xueying , Lee Tong H. , Liu Yingmiao , Wetsel William C. , Zhang Xiuwu 
Published: August 2008

AbstractBehavioral sensitization of psychostimulants was accompanied by alterations in a variety of biochemical molecules in different brain regions. However, which change is actually related to drug‐produced sensitization lacks of accurate clarification. In this study, we investigated the role of integrin‐linked kinase (ILK) in both the induction and expression of cocaine sensitization. Conditional inhibition of ILK expression was established in the nucleus accumbens (NAc) core by microinjecting recombinant adeno‐associated virus‐carrying, tetracycline‐on‐regulated small interfering RNA which reversed the chronic cocaine‐induced psychomotor sensitization, as well as the changes in protein kinase B Ser473 phosphorylation, dendritic density, and dendritic spine numbers locally. Importantly, the reversed psychomotor sensitization did not recover after cessation of the silencing for 8 days. We also demonstrated that inhibition of ILK expression pre‐ and during‐chronic cocaine treatments blocked the induction of cocaine psychomotor sensitization and abolished the stimulant effect of cocaine on ILK expression. In contrast, inhibition of ILK expression in the NAc core has no significant effect on cocaine‐induced stereotypical behaviors. This concludes that ILK is involved in cocaine sensitization with the earlier induction and later expression functioning as a kinase to regulate protein kinase B Ser473 phosphorylation and a scaffolding protein to regulate the reorganization of the NAc spine morphology.
Eradicating Helicobacter pylori in Peptic Ulcer Disease Reduces Medical Costs in the Community
Authors: Sone Yasuhiro , Kumada Takashi , Toyoda Hidenori , Yokoyama Mitsuyoshi , Kato Mototsugu , Asaka Masahiro 
Published: August 2008

AbstractBackground:  Eradicating Helicobacter pylori markedly reduces ulcer recurrence in patients with peptic ulcer disease (PUD). Many decision analysis studies have concluded that eradicating H. pylori in PUD patients is more cost‐effective than maintaining antisecretory therapy. In 1995, we introduced an H. pylori eradication program into a large transportation company that experienced increased incidences of PUD among its employees along with increased medical costs, and we performed trend analysis of the actual medical costs of PUD in this cohort.Methods:  In this cohort, there were approximately 8500 employees. H. pylori‐positive PUD patients were identified at the annual health check up. The patients received eradication therapy with lansoprazole, amoxicillin, and clarithromycin. After eradication, the patients were followed up by a yearly health check up. The annual number of patients who received eradication was recorded, and the annual direct medical costs of PUD therapy were analyzed.Results:  A total of 440 H. pylori‐positive PUD patients received eradication therapy in a 7‐year period. Based on an intention‐to‐treat analysis, the eradication rate was 84.5% (372 of 440). The largest number of patients who received eradication therapy was found in 1995 (n = 115), and from 1995 to 2001 this number decreased yearly by 12.5 (95% confidence interval (CI): 5 to 20). Between 1989 and 1995, the annual medical costs arising of PUD therapy increased by ¥2.25 million (95% CI: 1.19 to 3.31) per year, being highest (¥22.75 million) in 1995. Between 1995 and 2001, the costs decreased by ¥3.88 million (95% CI: 3.16 to 4.59) per year. The cost in 2001 was 5.7% of the cost in 1995. The eradication program was terminated in 2001 because the prevalence of PUD diminished markedly, and the associated medical costs decreased as well.Conclusions:  H. pylori eradication could reduce the number of PUD patients and associated medical costs in the workplace setting.
The relationship between periodontal disease and preterm low birthweight: clinical and microbiological results
Authors: Vettore M. V. , Leão A. T. , Leal M. do C. , Feres M. , Sheiham A. 
Published: August 2008

Background and Objective:  Findings on the effect of periodontal disease on preterm low birthweight are inconclusive. The objective of this study was to compare periodontal clinical measures and the levels and proportions of 39 bacterial species in subgingival biofilm samples in puerperal women with preterm low birthweight and nonpreterm low birthweight.Material and Methods:  A case‐control study with 116 postpartum women over 30 years of age was conducted. Four case groups of subjects with preterm and/or low birthweight [preterm (n = 40), low birthweight (n = 35), preterm and/or low birthweight (n = 50) and preterm and low birthweight (n = 25)] were compared with normal nonpreterm low‐birthweight controls (n = 66). Periodontal clinical parameters of dental plaque, calculus, bleeding on probing, periodontal pocket depth and clinical attachment level were recorded. Covariates included socio‐demographic and anthropometric characteristics, smoking, alcohol consumption, obstetric history, prenatal care and diseases during pregnancy. Two subgingival biofilm samples per women were analyzed for 39 bacterial species using a checkerboard DNA–DNA hybridization technique.Results:  The mean periodontal pocket depth was significantly higher in nonpreterm low‐birthweight controls than in subjects in the preterm low birthweight, preterm and/or low birthweight, and preterm and low‐birthweight groups. Clinical attachment level measures were not different between all pairs of cases and control groups. Groups did not differ with respect to the mean proportions of different microbial complexes. The mean counts of Treponema socranskii were lower in all case groups compared with the control group.Conclusion:  Maternal periodontal microbiota and clinical characteristics of periodontal disease were not associated with having preterm low‐birthweight babies.