bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhanced activity of a hydrogen sulphide‐releasing derivative of mesalamine (ATB‐429) in a mouse model of colitis
Authors: Fiorucci S , Orlandi S , Mencarelli A , Caliendo G , Santagada V , Distrutti E , Santucci L , Cirino G , Wallace J L
Published: March 2007

Background and Purpose:

Mesalamine is the first‐line therapy for colitis, but it lacks potency and is only effective for mild‐to‐moderate forms of this disease. Hydrogen sulphide has been shown to be a potent, endogenous anti‐inflammatory substance, modulating leukocyte‐endothelial adhesion and leukocyte migration. The purpose of this study was to determine if an H2S‐releasing derivative of mesalamine (ATB‐429) would exhibit increased potency and effectiveness in a mouse model of colitis.

Experimental Approach:

Colitis was induced in mice with trinitrobenzene sulphonic acid and the effects of ATB‐429 and mesalamine were compared in several treatment regimens. The severity of colitis was determined using several indices, including a disease activity score (comprised of scores for diarrhea, weight loss and fecal blood), colonic myeloperoxidase activity and macroscopic/microscopic scoring of tissue injury.

Key Results:

Irrespective of the treatment regiment, ATB‐429 was more effective than mesalamine in reducing the severity of colitis. ATB‐429 was particularly effective in reducing granulocyte infiltration into the colonic tissue (by ∼70%), as well as reducing the expression of mRNA for several key proinflammatory cytokines/chemokines (e.g., TNFα, IFNγ). Treatment with ADT‐OH, the H2S‐releasing moiety of ATB‐429, did not affect severity of colitis.

Conclusions and Implications:

ATB‐429 exhibits a marked increase in anti‐inflammatory activity and potency in a murine model of colitis, as compared to mesalamine. These results are consistent with recently described anti‐inflammatory effects of H2S. ATB‐429 may represent an attractive alternative to mesalamine for the treatment of inflammatory bowel disease.

British Journal of Pharmacology (2007) 150, 996–1002. doi:10.1038/sj.bjp.0707193
X-ray waveguide nanostructures: Design, fabrication, and characterization
Authors: Jarre A. , Seeger J. , Ollinger C. , Fuhse C. , David C. , Salditt T.
Published: March 2007

Two dimensionally confining x-ray channel waveguide structures are fabricated and used for the delivery of nanoscopic x-ray beams. The waveguides can be combined with a high gain Kirkpatrick-Baez-prefocusing mirror system yielding hard x-ray beams with a cross section down to 25nm (full width at half maximum). The incoming synchrotron x-ray beam is coupled in from the front side of the waveguide. Here we address the general design of the x-ray optical devices and their fabrication by e-beam lithography methods.
Determination of thermal and optical properties of ion implanted polyetheretherketone films by photothermal spectroscopies
Authors: de Albuquerque J. E. , Tavenner E. , Curry M. , Giedd R. E. , Meredith P.
Published: March 2007

Photothermal spectroscopies, photopyroelectric spectroscopy and photoacoustic spectroscopy (PAS), were used to study the thermal and optical properties of untreated and N+ ion implanted polyetheretherketone (PEEK) films. The photopyroelectric (PPE) intensity signal and its phase were independently measured as a function of wavelength and chopping frequency in the saturation part of the PPE spectrum. Equations for both the intensity and the phase of the PPE signal were used to fit the experimental results. From these fits we obtained the thermal diffusivity coefficient, the thermal conductivity, and the specific heat of the samples, as well as a value for the condensed phase optical gap. Additionally, using PAS we carried out a quantitative depth profile analysis of the optical properties of the ion implanted PEEK films. Since the thermal diffusion length varies inversely with the square root of chopping modulation frequency, at high chopping frequencies surface information is obtained. At low chopping frequencies information concerning the properties of the bulk is obtained. The overall objectives of this study are to understand and quantify how ion implantation affects the thermal and optical properties of the polymer, particularly within the implant region. We find that significant changes do occur, and our results have implications for the use of ion implantation to create plastic electronic and sensor devices.
Evaluation of interfacial-layer capacitance from fast polarization retention in ferroelectric thin films
Authors: Jiang A. Q. , Lin Y. Y. , Tang T. A.
Published: March 2007

We distinctly identify interfacial layers with damaged ferroelectricity within Pt∕Pb(Zr0.4Ti0.6)O3∕Pt∕Ti∕SiO2∕Si thin-film capacitors on the basis of fast polarization retention. The retention that deteriorates with the decrease of film thickness arises from the increase of depolarizing field across the ferroelectric layer. The depolarizing field backswitches partial domains into their previous orientations after the applied voltage. Numerical modeling through discharging of polarization charges within interfacial layers yields the interfacial capacitance density of 0.33±0.05F∕m2, independent of the electrode size and film thickness.
Oscillating behavior of high-pressure stability observed in the immiscible Co–Cu system by first-principles calculation
Authors: Kong Yi , Li Jiahao , Liu Baixin
Published: March 2007

Based on the density functional perturbation theory, the phonon spectra of the immiscible Co–Cu compound under different pressures are calculated. It is found that the CoCu3 compound can be stabilized under certain high pressure, further confirming the recently proposed concept of high-pressure alloying between immiscible elements [Dubrovinskaia et al., Phys. Rev. Lett. 95, 245502 (2005)]. Interestingly, alternately appearing imaginary phonons are observed under different pressures, suggesting that there exists an oscillation behavior of the stability of the CoCu3 compound under high pressure, which deepens the understanding of the concept of high-pressure alloying between immiscible elements.
Piezoelectric properties of (Li, Sb, Ta) modified (Na,K)NbO3 lead-free ceramics
Authors: Ming Bao-Quan , Wang Jin-Feng , Qi Peng , Zang Guo-Zhong
Published: March 2007

Lead-free alkaline niobate based (Na0.52K0.48−xLix)Nb1−x−ySbxTayO3 piezoceramics have been prepared by the conventional mixed oxide method without using other techniques. An experimental formula for producing a set of ceramics with high piezoelectric properties is obtained while cutting down the Ta content and maintaining a high Curie temperature. The highest piezoelectric constant d33 is 308pC∕N, with a dielectric loss tanδ of about 2.0% and a Curie temperature of 339°C. The samples also possess outstanding high-field piezoelectric strain effects. The high-field piezoelectric strain coefficient d33* is as high as 490pm∕V. (Li, Sb, Ta) modified (Na,K)NbO3 shifts the orthorhombic to tetragonal phase transition to near room temperature, which plays an important role in the improvement of the piezoelectric properties.
Differential magnetostrictive response in magnetically annealed Tb0.36Dy0.64(Fe0.85Co0.15)2 with ⟨110⟩ crystal orientation
Authors: Ma Tianyu , Yan Mi , Zhang Jingjing , Luo Wei , Jiang Chengbao , Xu Huibin
Published: March 2007

Magnetic heat treatment has been carried out on a giant magnetostrictive alloy Tb0.36Dy0.64(Fe0.85Co0.15)2 with ⟨110⟩ crystal orientation. A dramatic improvement in magnetostriction along and perpendicular to the crystal axis (defined as λ‖ and λ⊥, respectively) occurs when cooling the sample through the Curie temperature TC under 240kA∕m applied perpendicular to its axis. When the applied annealing field was parallel to the crystal axis, the magnetostrictive behavior becomes “anomalous;” negative λ‖ and positive λ⊥ are obtained in low fields, accompanied with relatively low values in high fields. A single-{111}-twin model has been suggested to explain such differential magnetostrictive response.
Small-scale drift-Alfven wave driven zonal flows in plasmas
Authors: Kaladze T. D. , Wu D. J. , Yang L.
Published: March 2007

The problem of generation of zonal flows by small-scale drift-Alfven waves is illuminated more completely. The growth rate of zonal-flow instabilities much greater than known by previous investigations is obtained. Dependence of the growth rate on the spectrum purity of the wave packet is also investigated. It is shown that the sufficient broadening of the wave packet gives resonant-type instability with the growth rate of the order of hydrodynamic one. The appropriate conditions for instabilities are determined.
Lithographic engineering of anisotropies in (Ga,Mn)As
Authors: Hümpfner S. , Pappert K. , Wenisch J. , Brunner K. , Gould C. , Schmidt G. , Molenkamp L. W. , Sawicki M. , Dietl T.
Published: March 2007

The focus of studies on ferromagnetic semiconductors is moving from material issues to device functionalities based on phenomena often associated with the anisotropy properties of these materials. This is driving a need for a method to locally control the anisotropy in order to allow the elaboration of devices. Here the authors present a method which provides patterning induced anisotropy that not only can be applied locally but also dominates over the intrinsic material anisotropy at all temperatures.
Influence of wall-charge accumulation on the gas dielectric barrier discharge in alternating current plasma display panel
Authors: Guo Bingang , Wei Wei , Shinoda Tsutae , Liu Chunliang
Published: March 2007

Influences of wall-charge accumulation on gas dielectric barrier discharge (DBD) breakdown threshold and sustaining voltage margin of alternating current plasma display panel (AC-PDP) were investigated. It is observed that wall-charge accumulation results in a remarkable increase of gas DBD breakdown threshold during sustaining discharge period. Sustaining voltage margin is reduced by the threshold increase. A larger margin can be obtained when the threshold is decreased by removing unfavorable influence of wall-charge accumulation. Compared with normal margin, improved margin has a larger value and a faster linear increase with increasing wall-charge voltage. That indicates a way to improve AC-PDP performances remarkably.
Study of the defect elimination mechanisms in aspect ratio trapping Ge growth
Authors: Bai J. , Park J.-S. , Cheng Z. , Curtin M. , Adekore B. , Carroll M. , Lochtefeld A. , Dudley M.
Published: March 2007

Recent research has demonstrated the effectiveness of the “aspect ratio trapping” technique for eliminating threading dislocations in Ge grown selectively in submicron trenches on Si substrates. In this letter, analysis of the mechanisms by which dislocation elimination is achieved has been carried out. Detailed transmission electron microscopy studies reveal that facets, when formed early in the growth process, play a dominant role in determining the configurations of threading dislocations in the films. These dislocations are shown to behave as “growth dislocations,” which are replicated during growth approximately along the facet normal and so are deflected out from the center of the selective epitaxial regions.
Integrated liquid core waveguides for nonlinear optics
Authors: Dumais Patrick , Callender Claire L. , Noad Julian P. , Ledderhof Christopher J.
Published: March 2007

A liquid core waveguide monolithically integrated with silica waveguides is demonstrated as a nonlinear optical device. Continuum generation is achieved using toluene as a core medium, with picosecond pulses at 1550nm wavelength. A 500nm wide spectrum is generated for an estimated peak input power of 60kW over a propagation length of 16mm.
Temperature dependence of pulse duration in a mode-locked quantum-dot laser
Authors: Cataluna M. A. , Viktorov E. A. , Mandel Paul , Sibbett W. , Livshits D. A. , Weimert J. , Kovsh A. R. , Rafailov E. U.
Published: March 2007

The authors demonstrate, experimentally and theoretically, that in a mode-locked two-section quantum-dot laser, the pulse duration decreases with temperature. The primary cause is the increase of carrier capture/escape rates with temperature that leads to faster absorption recovery.
Antibunching observed in cold, dense gases of fermionic atoms
Authors: Day Charles
Published: March 2007

A two-body correlation could help elucidate many-body phenomena, including the emergence of high-T c superconductivity.
Solar energy conversion
Authors: Crabtree George W. , Lewis Nathan S.
Published: March 2007

If solar energy is to become a practical alternative to fossil fuels, we must have efficient ways to convert photons into electricity, fuel, and heat. The need for better conversion technologies is a driving force behind many recent developments in biology, materials, and especially nanoscience.
The Use of Internal Models: Comparison of the New Basel Credit Proposals with Available Internal Models for Credit Risk
Authors: Crouhy Michel , Galai Dan , Mark Robert
Published: March 2007

This chapter presents the New Capital Adequacy Accord proposed by the Basel Committee on Banking Supervision (Basel II) to replace the current 1988 Capital Accord (Basel I) by a more risk-sensitive framework for the measurement of credit risk. Basel II offers a menu of approaches: the “standardized” approach and the “internal ratings based” (IRB) approach with two variants: the “foundation” and the “advanced” approaches. These approaches are reviewed and their shortcomings are discussed. The standardized approach presents similar flaws to Basel I. The regulatory capital attribution according to the IRB approach is compared with the economic capital allocation from the industry-sponsored credit portfolio models, including CreditMetrics, KMV, and CreditRisk+. This comparison shows that the capital attribution for investment grade facilities from the IRB approach, although much lower than for the standardized approach, is still too high compared with the allocation from internal models. For subinvestment grade portfolios, the opposite is true where the IRB approach allocates more capital than the standardized approach, but still much less than the internal models. It is also noted that when the various credit portfolio models are calibrated with consistent parameters, they produce capital attributions that are relatively close to one another. It is clear from these conclusions that regulatory arbitrage will prevail as banks will be incentivized, as under Basel I, to shed away their high-quality assets through loan sales and securitization, and keep on their balance sheet the more risky loans for which regulatory capital underestimates the actual economic risk.
Enforcement of Risk‐Based Capital Rules
Authors: Wellons Philip A.
Published: March 2007

This chapter examines the role of enforcement for capital adequacy regulation in US banking and securities markets. Very little is known about how enforcement works: What broken rules are being enforced? By whom? How serious are the violations? How effective is enforcement, which presumably should discourage others from breaking important capital rules? The data are from enforcement actions over the last 6 to 10 years by US regulators, who are unique in publishing them. Even though the capital adequacy rules differ for banks and securities firms, the approaches to enforcing them overlap enough to allow rough comparison. This chapter finds a very low number of formal enforcement actions. Most target the small firms or individuals, not the big firms. Formal actions are particularly rare against the largest banks and securities firms, those that pose the greatest threat to the financial system. All but one of the capital adequacy violations resulted from fraud, theft, or other forms of operational risk. Only one resulted from credit risk. The chapter examines possible explanations of the findings, such as the relatively strong economy during much of the period and the possibility that very effective supervision catches almost all firms before their capital falls too low. Evidence from case studies of failed banks suggests that supervisors need to do a better job relating a bank's apparently adequate capital to its risk exposure, and to force banks to implement proposals regulators make to remedy deficiencies. Perhaps the very limited enforcement against large firms reflects a regulatory bias in their favor rather than their underlying strength and adequate capital.
A comprehensive crop genome research project: the Superhybrid Rice Genome Project in China
Authors: Yu Jun , Ka-Shu Wong Gane , Liu Siqi , Wang Jian , Yang Huanming
Published: March 2007

In May 2000, the Beijing Institute of Genomics formally announced the launch of a comprehensive crop genome research project on rice genomics, the Chinese Superhybrid Rice Genome Project. SRGP is not simply a sequencing project targeted to a single rice (
Oryza sativa
L.) genome, but a full-swing research effort with an ultimate goal of providing inclusive basic genomic information and molecular tools not only to understand biology of the rice, both as an important crop species and a model organism of cereals, but also to focus on a popular superhybrid rice landrace,
LYP9
. We have completed the first phase of SRGP and provide the rice research community with a finished genome sequence of an
indica
variety,
93-11
(the paternal cultivar of
LYP9
), together with ample data on subspecific (between subspecies) polymorphisms, transcriptomes and proteomes, useful for within-species comparative studies. In the second phase, we have acquired the genome sequence of the maternal cultivar,
PA64S
, together with the detailed catalogues of genes uniquely expressed in the parental cultivars and the hybrid as well as allele-specific markers that distinguish parental alleles. Although SRGP in China is not an open-ended research programme, it has been designed to pave a way for future plant genomics research and application, such as to interrogate fundamentals of plant biology, including genome duplication, polyploidy and hybrid vigour, as well as to provide genetic tools for crop breeding and to carry along a social burden—leading a fight against the world's hunger. It began with genomics, the newly developed and industry-scale research field, and from the world's most populous country. In this review, we summarize our scientific goals and noteworthy discoveries that exploit new territories of systematic investigations on basic and applied biology of rice and other major cereal crops.
Outcome after admission to ITU following out‐of‐hospital cardiac arrest: are non‐survivors suitable for non‐heart‐beating organ donation?
Authors: Gratrix Andrew P. , Pittard Alison J. , Bodenham Andrew R.
Published: March 2007

We have reviewed retrospective data from two large UK teaching hospitals regarding outcome following out‐of‐hospital cardiac arrest and the suitability of non‐survivors for non‐heart‐beating organ donation. Patients were selected retrospectively from consecutive admissions from two intensive care units who had presented following out‐of‐hospital cardiac arrest, to a total of 50 patients in each centre. They had all been resuscitated to achieve a spontaneous cardiac output at the scene, in transit or after arrival in hospital, and required further intensive care support due to cardiovascular, respiratory, or neurological impairment. Eighty‐six patients (86%) died in the Intensive Care Unit and only 14 (14%) survived to discharge from the Unit. A further nine (9%) patients died in hospital before discharge home. Four patients (4%) were alive after 6 months and three (3%) were alive after 1 year. Fifty‐seven (57%) of patients had active withdrawal of treatment with only four (4%) being potentially suitable for organ procurement having not been excluded because of age, medical history or the length of time to die following withdrawal of treatment. Our results show that only a small increase in donor organs could be potentially achieved from this population. Further work is required to determine whether such patients should be considered as non‐heart‐beating donors.
Behavioural treatment of severe food refusal in five toddlers with developmental disabilities
Authors: De Moor J. , Didden R. , Korzilius H.
Published: March 2007

Background  Young children with developmental disabilities are at risk of food refusal. In case of severe food refusal, children are being fed by nasal or gastrostomy tube. Behavioural treatment may be effective in establishing oral food intake.

Methods  A behavioural treatment package was implemented in an outpatient setting for the treatment of severe food refusal in five toddlers with developmental disabilities. During the course of treatment, treatment principles were generalized to parents in the home setting.

Results  Treatment resulted in oral acceptance of a variety of food items in each child and was successfully generalized. Treatment effects were maintained during follow‐up between 3 and 12 months. Tube feeding was discontinued in each child and health status of each child improved.

Conclusions  Behavioural treatment may be highly effective in establishing oral food intake in children with developmental disabilities (in the absence of organic causes). As a side‐effect of this treatment, tube‐feeding may be discontinued and general heath status improved.
Nurses’ experiences of caring for families with relatives in intensive care units
Authors: Stayt Louise Caroline
Published: March 2007

Aim.  This paper reports an exploratory study of nurses’ experiences of caring for families who have relatives in adult intensive care units.

Background.  The admission of a critically ill patient into adult intensive care is universally accepted as a crisis for both patients and their families. Family members of critically ill people may experience emotional turmoil and therefore have many needs throughout the course of the relative’s illness. It has been identified that nurses are best placed to meet families’ needs. Whilst there is a substantial evidence base associated with family needs, little is known about nurses’ experiences of caring for these families.

Method.  Interviews, informed by Heideggerian philosophy, were conducted with a purposive sample of 12 Registered Nurses working in an adult intensive care unit. Interview transcripts were analysed using Colaizzi's framework. The data were collected in Autumn 2005.

Findings.  Participants’ experiences were categorized into the following themes: defining the nurse's role, role expectations and role conflict. Participants reported lack of confidence, doubts about their professional competence and conflicts between their professional and personal self. These experiences were linked to participants’ expectations and self‐imposed standards.

Conclusion.  Registered Nurses caring for families who have relatives in adult intensive care units face a fundamental conflict both between role expectations and patient care and between professional ideals and being a human. This not only highlights a disparity between nurses everyday family care practice and the underpinning theories but also may contribute to occupational stress.
Effects of herbicide spray drift and fertilizer overspread on selected species of woodland ground flora: comparison between short‐term and long‐term impact assessments and field surveys
Authors: GOVE B. , POWER S. A. , BUCKLEY G. P. , GHAZOUL J.
Published: March 2007

Although application of fertilizers and pesticides to farmland is known to impact non‐target organisms in adjacent semi‐natural habitats, little is known of the impact on woodland understorey communities, which have considerable conservation significance in the arable landscapes of the UK and elsewhere in Europe. This study investigated the impacts of agrichemicals on several plant species typically found in ancient semi‐natural communities.

Six species of woodland plants were exposed to the herbicide glyphosate at concentrations equivalent to those measured in spray drift trials (1–25% of the full application rate) in short‐term greenhouse and long‐term field experiments. Fertilizer was applied to half of the plants at a concentration likely to be seen in overspread situations (70 kg ha−1 year−1). The distribution of the same species was surveyed in woodland margins adjacent to fields with high, medium and low agrichemical inputs.

In both greenhouse and field experiments, herbicide treatments at drift concentrations caused increased mortality, reduced biomass and reduced fecundity in all species, although to differing degrees. The threshold of sensitivity to glyphosate was as low as 1% of the median field application rate for the most sensitive species. Fertilizer treatment affected resource partitioning in Carex remota and Galium odoratum and reduced the fecundity of G. odouratum.

In field surveys, the abundance of the most sensitive species was highest in woodland margins adjacent to fields with low agrichemical inputs and lowest beside high‐input farmland. These differences were seen at least 4 m into woodland margins but were not found at 10 m.

Synthesis and applications. There was considerable agreement between the short‐term greenhouse and long‐term field experiments, although long‐term impacts may have been underestimated in the former. Adverse impacts of pesticide drift have been demonstrated to affect a variety of plants of woodland margins bordering farmland. Differences in the distribution of species most sensitive to herbicide extend to at least 4 m into woodland margins. We recommend the adoption of no‐spray buffer zones of at least 5 m to protect the majority of woodland species from the impacts of agrichemicals applied to adjacent land.
Population dynamics and responses to management of plateau pikas Ochotona curzoniae
Authors: PECH ROGER P. , JIEBU  , ARTHUR ANTHONY D. , YANMING ZHANG , HUI LIN
Published: March 2007

Plateau pikas Ochotona curzoniae are considered a pest species on the Tibetan Plateau because they compete with livestock for forage and their burrowing could contribute to soil erosion. The effectiveness of pest control programmes in Tibet has not been measured, and it is not known whether changes in livestock management have exacerbated problems with plateau pikas or compromised their control. This study measured the impact of control programmes and livestock management for forage conservation on populations of plateau pikas in alpine meadow in Naqu District, central Tibet, during 2004 and 2005.

Current techniques for controlling plateau pikas in spring cause large reductions in abundance, but high density‐dependent rates of increase result in no differences between treated and untreated populations by the following autumn. Rates of increase from spring to autumn are not influenced by standing plant biomass or concurrent grazing by yaks Bos grunniens and Tibetan sheep Ovis aries.

In autumn there was significantly lower biomass outside fenced areas with year‐round livestock grazing compared with inside fenced areas with equivalent or higher numbers of plateau pikas but predominantly winter grazing by livestock. Inside fenced areas, control of plateau pikas in spring produced no detectable effect on standing plant biomass at the end of the following summer compared with uncontrolled populations of plateau pikas.

Regardless of their initial density, populations of plateau pikas declined rapidly over winter outside fenced areas where there was very low standing plant biomass in autumn. However, inside fenced areas with higher plant biomass in autumn, low‐density populations of plateau pikas declined more slowly than high‐density populations.

Synthesis and applications. Current control programmes have limited effect because populations of plateau pikas can recover in one breeding season. There was no apparent increase in forage production in areas where plateau pikas were controlled. However, plateau pikas appear to benefit from changes in grazing management, with low‐density populations declining less over winter inside fenced areas than elsewhere. It was not evident that control programmes are warranted or that they will improve the livelihoods of Tibetan herders.
Inhibition of Vasopressin V1b Receptor Translation By Upstream Open Reading Frames in the 5′‐Untranslated Region
Authors: Rabadan‐Diehl C. , Martínez A. , Volpi S. , Subburaju S. , Aguilera G.
Published: March 2007

The 5′‐UTR of the vasopressin V1b receptor (V1bR) mRNA contains small open reading frames (ORF) located upstream (u) of the main ORF encoding the V1bR. The ability of the three proximal uORFs to be translated into peptides and their influence on V1bR translation was examined using fusion constructs of uORFs and V5 epitope, or ATG/ATA uORF mutations in the V1bR cDNA. In vitro translation and western blot analysis after transfection of uORF1‐V5 or uORF2‐V5 into cells revealed that uORF1 can be translated. As predicted by computer analysis, in vitro translation using a rabbit reticulocyte/canine microsome system, immunohistochemistry and western blot in membranes of transfected cells with uORF1‐V5 revealed translocation of the uORF1 peptide into membrane fractions. In vitro translation of V1bR cDNA with mutations of the two uORFs proximal to the initiating methionine, uORFs 1 and 2 (Mut 1–2), or uORF2 (Mut 2) showed significantly increased translation of a 46 kDa band corresponding to the V1bR, compared with wild‐type (WT) V1bR, an effect that was attenuated by cotranslation of uORF1‐V5. Consistently, VP‐induced inositol phosphate formation was higher in Chinese hamster ovay cells transfected with Mut 1–2 than with WT V1bR. Immunohistochemical and western blot analysis, using an antibody against uORF1, revealed peptide immunoreactivity in rat pituitary but not in liver. Pituitary uORF immunoreactivity increased following glucocorticoid administration. The present study shows that uORFs in the 5′‐UTR of the V1bR mRNA inhibit V1bR translation, and suggests that translation of a 38‐amino acid membrane peptide encoded by uORF1 exerts tonic inhibition of V1bR translation.
An NB‐LRR protein required for HR signalling mediated by both extra‐ and intracellular resistance proteins
Authors: Gabriëls Suzan H.E.J. , Vossen Jack H. , Ekengren Sophia K. , Ooijen Gerben van , Abd‐El‐Haliem Ahmed M. , Berg Grardy C.M. van den , Rainey Daphne Y. , Martin Gregory B. , Takken Frank L.W. , Wit Pierre J.G.M. de , Joosten Matthieu H.A.J.
Published: March 2007

Tomato (Solanum lycopersicum) Cf resistance genes confer hypersensitive response (HR)‐associated resistance to strains of the pathogenic fungus Cladosporium fulvum that express the matching avirulence (Avr) gene. Previously, we identified an Avr4‐responsive tomato (ART) gene that is required for Cf‐4/Avr4‐induced HR in Nicotiana benthamiana as demonstrated by virus‐induced gene silencing (VIGS). The gene encodes a CC‐NB‐LRR type resistance (R) protein analogue that we have designated NRC1 (NB‐LRR protein required for HR‐associated cell death 1). Here we describe that knock‐down of NRC1 in tomato not only affects the Cf‐4/Avr4‐induced HR but also compromises Cf‐4‐mediated resistance to C. fulvum. In addition, VIGS using NRC1 in N. benthamiana revealed that this protein is also required for the HR induced by the R proteins Cf‐9, LeEix, Pto, Rx and Mi. Transient expression of NRC1D481V, which encodes a constitutively active NRC1 mutant protein, triggers an elicitor‐independent HR. Subsequently, we transiently expressed this auto‐activating protein in N. benthamiana silenced for genes known to be involved in HR signalling, thereby allowing NRC1 to be positioned in an HR signalling pathway. We found that NRC1 requires RAR1 and SGT1 to be functional, whereas it does not require NDR1 and EDS1. As the Cf‐4 protein requires EDS1 for its function, we hypothesize that NRC1 functions downstream of EDS1. We also found that NRC1 acts upstream of a MAP kinase pathway. We conclude that Cf‐mediated resistance signalling requires a downstream NB‐LRR protein that also functions in cell death signalling pathways triggered by other R proteins.
Regulation and functional analysis of ZmDREB2A in response to drought and heat stresses in Zea mays L
Authors: Qin Feng , Kakimoto Masayuki , Sakuma Yoh , Maruyama Kyonoshin , Osakabe Yuriko , Tran Lam‐Son Phan , Shinozaki Kazuo , Yamaguchi‐Shinozaki Kazuko
Published: March 2007

DREB1/CBFs and DREB2s are transcription factors that specifically interact with a cis‐acting element, DRE/CRT, which is involved in the expression of genes responsive to cold and drought stress in Arabidopsis thaliana. The function of DREB1/CBFs has been precisely analyzed and it has been found to activate the expression of many genes responsive to cold stress containing a DRE/CRT sequence in their promoters. However, the regulation and function of DREB2‐type transcription factors remained to be elucidated. In this research, we report the cloning of a DREB2 homolog from maize, ZmDREB2A, whose transcripts were accumulated by cold, dehydration, salt and heat stresses in maize seedlings. Unlike Arabidopsis DREB2A, ZmDREB2A produced two forms of transcripts, and quantitative real‐time PCR analyses demonstrated that only the functional transcription form of ZmDREB2A was significantly induced by stresses. Moreover, the ZmDREB2A protein exhibited considerably high transactivation activity compared with DREB2A in Arabidopsis protoplasts, suggesting that protein modification is not necessary for ZmDREB2A to be active. Constitutive or stress‐inducible expression of ZmDREB2A resulted in an improved drought stress tolerance in plants. Microarray analyses of transgenic plants overexpressing ZmDREB2A revealed that in addition to genes encoding late embryogenesis abundant (LEA) proteins, some genes related to heat shock and detoxification were also upregulated. Furthermore, overexpression of ZmDREB2A also enhanced thermotolerance in transgenic plants, implying that ZmDREB2A may play a dual functional role in mediating the expression of genes responsive to both water stress and heat stress.
Soya Bean (Glycine max L. Merr.) Genotype Response to Early‐season Flooding: II. Aboveground Growth and Biomass
Authors: Henshaw T. L. , Gilbert R. A. , Scholberg J. M. S. , Sinclair T. R.
Published: March 2007

Soya bean is often grown in regions prone to periodic flooding, thus selecting cultivars that maintain production under waterlogged conditions is desirable. An experiment involving flooded soya beans was planted in southern Florida to examine (1) stem and leaf growth; (2) morphological adaptations; and (3) the relationship between early‐season and late‐season flood tolerance in flooded soya beans. Eleven soya bean genotypes previously defined as tolerant or sensitive to flooding were subjected to three treatments at 21 days after sowing (DAS): (1) no flood, (2) 2‐week flood and (3) 4‐week flood. All plants were harvested 49 DAS. Flooded plants exhibited lower stem dry weights but greater partitioning to the stem. Non‐flood treatments had greater leaf dry weight, leaf area and partitioning to leaves than flooded plants. There were positive correlations of genotype stem dry weight and leaf dry weight to early‐season flood tolerance but stem partitioning was negatively correlated with early‐season flood tolerance. Genotypic rankings of early‐season flood tolerance in this study were not correlated with earlier studies basing flood tolerance on seed yield. Our study highlights the range of soya bean morphological adaptations in response to flood. However, our results indicate that early‐season screening may not be an accurate predictor of soya bean genotypic response to late‐season flood.
El Niño events, the lean versus fat scenario, and long‐term guild dynamics of vertebrate predators in a South American semiarid ecosystem
Authors: FARIAS ARIEL A. , JAKSIC FABIAN M.
Published: March 2007

Abstract  Predator assemblages are complex systems in which asynchrony in the dynamics of resources and consumers, and the idiosyncratic perception of environmental conditions by the predators may obscure the detection of expected patterns. We disentangle the specific effects of these variables on the guild structure of a vertebrate predatory assemblage in a semiarid ecosystem of western South America. Over 16 years, this system faced dramatic fluctuations in prey availability associated with four El Niño events. After controlling for other sources of variation, we tested if increased resource availability is associated with higher niche overlaps, as expected from the lean/fat scenario. We determined the existence of two trophic guilds of predators (specialized mammal‐eaters and omnivorous species with emphasis on arthropods) and found that they responded to increased productivity both at the guild and whole assemblage levels. However, the population response of arthropod prey (almost simultaneous) and of different small mammal prey (delayed by 1 or 2 years) to productivity imposed a degree of asynchrony in prey availability and in the response of predators. This resulted in the between‐guilds exchange of predator species depending on mammal prey scarcity or abundance. As a consequence, the observed pattern was an apparent lack of response at the assemblage level. Despite differences in the perception of prey levels by predators, we conclude that each one of them responded accordingly to theoretical predictions following a simple rule: if prey resources are not limiting, predators behave opportunistically converging over the most abundant resources, thus increasing niche overlap; if prey shortages occur, predators specialize on those prey resources that they gather most efficiently, thus lowering niche overlap; if resources become even scarcer, all predators converge again upon the few prey resources still available, thus increasing overlap – out of necessity.
INTERNATIONAL TRENDS IN WATER UTILITY REGIMES
Authors: Madhoo Yeti Nisha
Published: March 2007

ABSTRACT**:  This paper provides the taxonomy of country experiences in managing their water utilities. Institutions for water supply for various uses and their financial implications are analysed. Different episodes of governmental intervention in water supply and charging are examined. From the survey of different regimes and the existing literature, cost recovery and affordability emerge as the major building blocks for any reform of water utilities. Privatization of water services in terms of ownership change, public‐private arrangements and international involvement seems to be a mixed blessing and donor assistance to water projects raises issues in international inequality and does not increase cost recovery levels. Cost recovery is positively associated with economic development, institutional quality and performance of water utilities.
Maximum Likelihood Inference On A Mixed Conditionally and Marginally Specified Regression Model for Genetic Epidemiologic Studies with Two-Phase Sampling
Authors: Chatterjee Nilanjan , Chen Yi-Hau
Published: March 2007

Two-phase stratified sampling designs can reduce the cost of genetic epidemiologic studies by limiting expensive ascertainments of genetic and environmental exposure to an efficiently selected subsample (phase II) of the main study (phase I). Family history and some covariate information, which may be cheaply gathered for all subjects at phase I, can be used for sampling of informative subjects at phase II. We develop alternative maximum likelihood methods for analysis of data from such studies by using a novel regression model that permits the estimation of ‘marginal’ risk parameters that are associated with the genetic and environmental covariates of interest, while simultaneously characterizing the ‘conditional’ risk of the disease associated with family history after adjusting for the other covariates. The methods and appropriate asymptotic theories are developed with and without an assumption of gene–environment independence, allowing the distribution of the environmental factors to remain non-parametric. The performance of the alternative methods and of sampling strategies is studied by using simulated data involving rare and common genetic variants. An application of the methods proposed is illustrated by using a case–control study of colorectal adenoma embedded within the prostate, lung, colorectal and ovarian cancer screening trial.
On the Non-Negative Garrotte Estimator
Authors: Yuan Ming , Lin Yi
Published: March 2007

We study the non-negative garrotte estimator from three different aspects: consistency, computation and flexibility. We argue that the non-negative garrotte is a general procedure that can be used in combination with estimators other than the original least squares estimator as in its original form. In particular, we consider using the lasso, the elastic net and ridge regression along with ordinary least squares as the initial estimate in the non-negative garrotte. We prove that the non-negative garrotte has the nice property that, with probability tending to 1, the solution path contains an estimate that correctly identifies the set of important variables and is consistent for the coefficients of the important variables, whereas such a property may not be valid for the initial estimators. In general, we show that the non-negative garrotte can turn a consistent estimate into an estimate that is not only consistent in terms of estimation but also in terms of variable selection. We also show that the non-negative garrotte has a piecewise linear solution path. Using this fact, we propose an efficient algorithm for computing the whole solution path for the non-negative garrotte. Simulations and a real example demonstrate that the non-negative garrotte is very effective in improving on the initial estimator in terms of variable selection and estimation accuracy.
On Fast Computation of the Non-Parametric Maximum Likelihood Estimate of a Mixing Distribution
Authors: Wang Yong
Published: March 2007

A fast algorithm for computing the non-parametric maximum likelihood estimate of a mixing distribution is presented. At each iteration, the algorithm adds new important points to the support set as guided by the gradient function, updates all mixing proportions via a quadratically convergent method and discards redundant support points straightaway. With its convergence being theoretically established, numerical studies show that it is very fast and stable, compared with several other algorithms that are available in the literature.
Probabilistic Forecasts, Calibration and Sharpness
Authors: Gneiting Tilmann , Balabdaoui Fadoua , Raftery Adrian E.
Published: March 2007

Probabilistic forecasts of continuous variables take the form of predictive densities or predictive cumulative distribution functions. We propose a diagnostic approach to the evaluation of predictive performance that is based on the paradigm of maximizing the sharpness of the predictive distributions subject to calibration. Calibration refers to the statistical consistency between the distributional forecasts and the observations and is a joint property of the predictions and the events that materialize. Sharpness refers to the concentration of the predictive distributions and is a property of the forecasts only. A simple theoretical framework allows us to distinguish between probabilistic calibration, exceedance calibration and marginal calibration. We propose and study tools for checking calibration and sharpness, among them the probability integral transform histogram, marginal calibration plots, the sharpness diagram and proper scoring rules. The diagnostic approach is illustrated by an assessment and ranking of probabilistic forecasts of wind speed at the Stateline wind energy centre in the US Pacific Northwest. In combination with cross-validation or in the time series context, our proposal provides very general, nonparametric alternatives to the use of information criteria for model diagnostics and model selection.
Inference and Model Choice for Sequentially Ordered Hidden Markov Models
Authors: Chopin Nicolas
Published: March 2007

The system equation of a hidden Markov model is rewritten to label the components by order of appearance, and to make explicit the random behaviour of the number of components, mt. We argue that this reformulation is often a good way to achieve identifiability, as it facilitates the interpretation of the posterior density, and the estimation of the number of components that have appeared in a given sample. We develop a sequential Monte Carlo algorithm for estimating the reformulated model, which relies on particle filtering and Gibbs sampling. Our algorithm has a computational cost that is similar to that of a Markov chain Monte Carlo sampler and is much less likely to be affected by label switching, i.e. the possibility of becoming trapped in a local mode of the posterior density. The extension to transdimensional priors is also considered. The approach is illustrated by two real data examples.
Regulation of working time in SMEs of the information and communication technology sector in France
Authors: Dupré Michèle , Lallement Michel
Published: March 2007

This paper focuses on the impact of the French working‐time reduction law on small and medium enterprises (SMEs) in the information and communication technology sector. After a presentation of the main features of this sector, made up of a wide range of SMEs, the paper aims at describing how the actors have negotiated the application of the new legal framework at sector and company levels. The new working‐time regulation outlines the status of high‐skilled employees (cadres) as a very important conflict and negotiation subject.
Topological analysis of the complex formed between neurokinin A and the NK2 tachykinin receptor
Authors: Zoffmann Sannah , Bertrand Sonia , Do Quoc‐Tuan , Bertrand Daniel , Rognan Didier , Hibert Marcel , Galzi Jean‐Luc
Published: March 2007

Neurokinin A stimulates physiological responses in the peripheral and central nervous systems upon interacting primarily with the tachykinin NK2 receptor (NK2R). In this study, the structure of NKA bound to the NK2R is characterised by use of fluorescence resonance energy transfer. Four fluorescent NKA analogues with Texas red introduced at amino acid positions 1, 4, 7 and 10 were prepared. When bound to a NK2R carrying enhanced green fluorescent protein at the N‐terminus, all peptides reduce green fluorescent protein fluorescence from 10% to 50% due to energy transfer. The derived donor‐acceptor distances are 46, 55, 59 and 69 Å for the fluorophore linked to positions 1–10, respectively. The monotonic increase in distance clearly indicates that the peptide adopts an extended structure when bound to its receptor.

The present data are used, in combination with rhodopsin structure, fluorescence studies, photoaffinity labelling and site‐directed mutagenesis data to design a computer model of the NKA‐NK2R complex. We propose that the N‐terminus of NKA is exposed and accessible to the extracellular medium. Subsequent amino acids of the NKA peptide become progressively more buried residues up to approximately one‐third of the transmembrane‐spanning domain.