bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of the exchange-correlation functionals for the physical description of spin transition phenomena by density functional theory methods: All the same?
Authors: Zein Samir , Borshch Serguei A. , Fleurat-Lessard Paul , Casida Mark E. , Chermette Henry
Published: January 2007

This study aims to assess present day density functionals in the description of spin crossover iron(II) complexes. Two recently synthesized spin crossover complexes were considered. Theoretical calculations were made using 53 of the most popular exchange-correlation density functionals with triple zeta plus polarization quality basis sets. The present work shows that even though different density functionals can lead to different energy gaps between spin states, most of them are very similar for these two compounds when a comparison between energy gaps is sought. The present work shows that even though different exchange correlations can lead to different energy gaps between spin states, the difference between these gaps calculated at different geometries and that calculated at a given reference geometry is surprisingly independent of the choice of functional. The reasons for the similarities and the differences among exchange and correlation functional combinations are discussed.
Performance of density functionals for first row transition metal systems
Authors: Jensen Kasper P. , Roos Björn O. , Ryde Ulf
Published: January 2007

This article investigates the performance of five commonly used density functionals, B3LYP, BP86, PBE0, PBE, and BLYP, for studying diatomic molecules consisting of a first row transition metal bonded to H, F, Cl, Br, N, C, O, or S. Results have been compared with experiment wherever possible. Open-shell configurations are found more often in the order PBE0>B3LYP>PBE∼BP86>BLYP. However, on average, 58 of 63 spins are correctly predicted by any functional, with only small differences. BP86 and PBE are slightly better for obtaining geometries, with errors of only 0.020Å. Hybrid functionals tend to overestimate bond lengths by a few picometers and underestimate bond strengths by favoring open shells. Nonhybrid functionals usually overestimate bond energies. All functionals exhibit similar errors in bond energies, between 42 and 53kJ∕mol. Late transition metals are found to be better modeled by hybrid functionals, whereas nonhybrid functionals tend to have less of a preference. There are systematic errors in predicting certain properties that could be remedied. BLYP performs the best for ionization potentials studied here, PBE0 the worst. In other cases, errors are similar. Finally, there is a clear tendency for hybrid functionals to give larger dipole moments than nonhybrid functionals. These observations may be helpful in choosing and improving existing functionals for tasks involving transition metals, and for designing new, improved functionals.
Transmission measurement at 10.6μm of Te2As3Se5 rib waveguides on As2S3 substrate
Authors: Vigreux-Bercovici C. , Bonhomme E. , Pradel A. , Broquin J.-E. , Labadie L. , Kern P.
Published: January 2007

The feasibility of chalcogenide rib waveguides working at λ=10.6μm has been demonstrated. The waveguides comprised a several micron thick Te2As3Se5 film deposited by thermal evaporation on a polished As2S3 glass substrate and further etched by physical etching in Ar or CF4∕O2 atmosphere. Output images at 10.6μm and some propagation losses roughly estimated at 10dB∕cm proved that the obtained structures behaved as channel waveguides with a good lateral confinement of the light. The work opens the doors to the realization of components able to work in the mid- and thermal infrared up to 20μm and even more.
In
Ga
N
∕
Ga
N
nanostripe grown on pattern sapphire by metal organic chemical vapor deposition
Authors: Ko T. S. , Wang T. C. , Gao R. C. , Lee Y. J. , Lu T. C. , Kuo H. C. , Wang S. C. , Chen H. G.
Published: January 2007

The authors have used metal organic chemical vapor deposition to grow InGaN∕GaN multiple quantum well (MQW) nanostripes on trapezoidally patterned c-plane sapphire substrates. Transmission electron microscopy (TEM) images clearly revealed that the MQWs grew not only on the top faces of the trapezoids but also on both lateral side facets along the [0001] direction defined by the selected area electron diffraction pattern. Meanwhile, dislocations that stretched from the interfaces between the GaN and the substrates did not pass through the MQWs in the TEM observation. Microphotoluminescence measurements verified that the luminescence efficiency from a single nanostripe was enhanced by up to fivefold relative to those of regular thin film MQW structures. Observation of the cathodoluminescence identified the areas of light emission and confirmed that enhanced emission occurred from the nanostripes.
Oligonucleotide microarray identification ofBacillus anthracisstrains using support vector machines
Authors: Doran M. , Raicu D. S. , Furst J. D. , Settimi R. , Schipma M. , Chandler D. P.
Published: January 2007

The capability of a custom microarray to discriminate between closely related DNA samples is demonstrated using a set of Bacillus anthracis strains. The microarray was developed as a universal fingerprint device consisting of 390 genome-independent 9mer probes. The genomes of B.anthracis strains are monomorphic and therefore, typically difficult to distinguish using conventional molecular biology tools or microarray data clustering techniques. Using support vector machines (SVMs) as a supervised learning technique, we show that a low-density fingerprint microarray contains enough information to discriminate between B.anthracis strains with 90% sensitivity using a reference library constructed from six replicate arrays and three replicates for new isolates.

Contact:  doran_michael@msn.com
The carboxyl-terminal part of the putative Berne virus polymerase is expressed by ribosomal frameshifting and contains sequence motifs which indicate that toro- and coronaviruses are evolutionary related
Authors: Snijder Eric J. , Boon Johan A.den , Bredenbeek Peter J. , Horzinek Marian C. , Rijnbrand Rene , Spaan Willy J.M.
Published: January 2007

Sequence analysis of the 3′ part (8 kb) of the polymerase gene of the torovirus prototype Berne virus (BEV) revealed that this area contains at least two open reading frames (provisionally designated ORF1a and ORF1b) which overlap by 12 nucleotides. The complete sequence of ORF1b (6873 nucleotides) was determined. Like the coronaviruses, BEV was shown to express its ORF1 b by ribosomal frameshifting during translation of the genomic RN A. The predicted tertiary RNA structure (a pseudoknot) in the toro- and coronaviral frameshift-directing region is similar. Analysis of the amino acid sequence of the predicted BEV ORF1b translation product revealed homology with the ORF1b product of coronaviruses. Four conserved domains were identified: the putative polymerase domain, an area containing conserved cysteine and histidine residues, a putative helicase motif, and a domain which seems to be unique for toroand coronaviruses. The data on the 3′ part of the polymerase gene of BEV supplement previously observed similarities between toro- and coronaviruses at the level of genome organization and expression. The two virus families are more closely related to each other than to other families of positive-stranded RNA viruses.
The selfish geneat 30: the origin and career of a book and its title
Authors: de Chadarevian Soraya
Published: January 2007

The 30th anniversary of Richard Dawkins'sThe selfish genecoincides with the opening for historical scholarship of the production files of the book's first edition at the archives of Oxford University Press. Using the information collected in the files, the essay reconstructs the Press history of the book, the author's and his enthusiastic editor's pre-publication expectations, and the early reception and subsequent career of the book, which made an impact on the scientific debate on behaviour and evolution as well as on the popular market. It also reflects on the changing notions of popularization and the place ofThe selfish genein those debates.
Occurrence of the Japanese seahorse Hippocampus mohnikei Bleeker 1854 from the Palk Bay coast of south‐eastern India
Authors: Thangaraj M. , Lipton A. P.
Published: January 2007

The occurrence of the Japanese seahorse, Hippocampus mohnikei is reported for the first time from the Palk Bay coast of south‐eastern India.
Movement of a South American perch Percichthys trucha in a mountain Patagonian lake during spawning and prespawning periods
Authors: Buria L. , Walde S. J. , Battini M. , Macchi P. J. , Alonso M. , Ruzzante D. E. , Cussac V. E.
Published: January 2007

Movement of the South American perch Percichthys trucha (Perciformes: Percichthyidae) was studied in a set of interconnected mountain lakes in northern Patagonia. Fish were tracked using attached acoustic tags and a fixed hydrophone array over two seasons, corresponding to the spawning (1999) and prespawning periods (2000). Percichthys trucha was found to move throughout the lake system, and to use a small, shallow, connected lake as a principal spawning area. In addition, detailed behavioural information was obtained for the spawning period. Most fish spent the initial 2 weeks descending from the littoral zone to depths of 5–8 m, presumably while feeding. Fish changed depth slowly, spending several days at each depth, and moving throughout the lake. A few days prior to the full moon, there was a change in behaviour thought to be associated with spawning, where the fish moved toward the vegetated littoral areas. Marked daily behaviour also began at this time, with movement to particular near‐shore locations at dusk, and return to slightly greater depths offshore at or before dawn. Study of the behaviour of P. trucha during the breeding season has highlighted the conservation significance of the main locations within the lake system.
Movement and home range in relation to dominance; a telemetry study on brown troutSalmo trutta
Authors: Höjesjö J. , ØKland F. , Sundström L. F. , Pettersson J. , Johnsson J. I.
Published: January 2007

By combining behavioural observations on adult resident brown troutSalmo truttain the laboratory with radio telemetry studies in a natural stream, information on movement and space use in relation to social status was obtained. Dominant individuals moved longer distances and also tended to have larger home ranges than subordinates during the summer. In general, home ranges were larger during daytime than at night. Fish were not strictly territorial since the average overlap in interquartile range was 36% during the summer. During the spawning period, the brown trout moved to specific spawning areas resulting in an increased overlap (89%) in space use. Subordinate individuals now tended to increase both home range and interquartile range and were also less frequently observed in spawning areas relative to dominants.
Variation of male reproductive apparatus in relation to fertilization modalities in the catfish families Auchenipteridae and Callichthyidae (Teleostei: Siluriformes)
Authors: Mazzoldi C. , Lorenzi V. , Rasotto M. B.
Published: January 2007

To investigate the relationship between fertilization modalities and the morphology of male reproductive apparatus, two species of Auchenipteridae, Auchenipterus nuchalis and Tatia intermedia, and six species of Callichthyidae, Callichthys callichthys, Corydoras aeneus, Corydoras bondi, Corydoras ehrhardti, Corydoras potaroensis and Hoplosternum littorale were studied. The species analysed show either internal or external fertilization, the latter including the so called ‘sperm drinking’ type of mating. An anal fin modified as an intromittent organ, a pair of seminal vesicles, and the release of sperm in the form of discrete bundles (spermatozeugmata) characterize the male reproductive apparatus of the internal fertilizer A. nuchalis. Seminal vesicles are present also in C. aeneus, C. bondi, C. ehrhardti, C. potaroensis and H. littorale, species performing ‘sperm drinking’ spawning. In contrast, regardless of the family, species showing the more classic type of external fertilization lack specialized accessory organs. Where occurring, the major function of seminal vesicles is the secretion of mucins. The role of these mucosubstances, in relation to spermatozeugmata formation, in internal fertilizers, or the protection of sperm passing through the female gut, in the ‘sperm‐drinking’ species, is discussed. Variation, between families, in the shape of testis and accessory structures, as well as in the type of spermatogenesis was found. Neither the reproductive modalities nor the phylogenetic relationships, however, appear to fully account for these differences.
Lactate down‐regulates cellular poly(ADP‐ribose) formation in cultured human skin fibroblasts
Authors: Wagner S. , Hussain M. Z. , Beckert S. , Ghani Q. P. , Weinreich J. , Hunt T. K. , Becker H. D. , Königsrainer A.
Published: January 2007

Background  Polyadenosine diphosphate‐ribose (poly(ADP‐ribose)) is a nuclear polymer which is derived from nicotinamide adenine dinucleotide (NAD+) catalysed by poly(ADP‐ribose) polymerase 1 (PARP‐1). Aside from the well known role of poly(ADP‐ribosyl)ation (pADPR) in DNA repair, pADPR is also involved in other cellular processes such as apoptosis and gene expression. However, the factors that regulate the level of pADPR are not fully elucidated. In view of the fact that healing wounds contain high concentrations of lactate (10–15 mm) and exogenous lactate reduce the NAD+ pool in cultured fibroblasts, we propose that high lactate lowers the level of nuclear pADPR.

Materials and methods  Neonatal human dermal fibroblasts (NHDF) were plated to subconfluence and allowed to adhere. Cells were treated with 15 mm l‐lactate and pADPR production was assessed by immunofluorescence analysis using 10H antibody. Difference in pADPR production was determined by calculation of positively stained cells compared to total cell numbers. Inhibition of PARP activity was tested by treatment with 100 µm 3‐aminobenzamide (3‐AB). Specificity of the lactate effect on pADPR synthesis was verified by using the analogue d‐lactate. The contents of nicotinamide adenine dinucleotide (NAD+) and its reduced form (NADH) in lactated and non‐lactated cell cultures were quantified by the enzymatic cyclic assay.

Results  We found that exogenous l‐lactate (15 mm) can significantly depress pADPR content in cultured fibroblasts. PARP‐1 activity was inhibited by 3‐AB and analogue d‐lactate showed no effect on pADPR synthesis. NAD+/NADH ratio was significantly lowered in lactated compared to non‐lactated cell culture.

Conclusions  Exogenous l‐lactate (15 mm) can depress pADPR content in cultured fibroblasts. In view of the fact that healing wounds contain such high concentrations of lactate, we propose that down regulation of pADPR is associated with elevated tissue repair via pADPR dependent gene expression. This observation is important in understanding the stimulation of lactate‐mediated protein expression during wound healing.
Hankel transform filters for dipole antenna radiation in a conductive medium
Authors: Kong F.N.
Published: January 2007

We discuss the Hankel transforms related to a particular application, i.e. the dipole antenna radiation in conductive media, such as the antenna radiation in sea‐bed electromagnetic applications. In this application, the electromagnetic wavefields decay very rapidly with distance. A good filter means that it can be used to evaluate weak fields.

Exponential sampling transforms a Hankel transform into a convolution equation, which must be solved to obtain the filter coefficients. Here, we use a direct matrix inversion method to solve the convolution equation in the sample domain, instead of the Fourier transform method and the Wiener–Hopf method, previously used to solve the convolution equation. This direct method is conceptually simple and is suitable for our optimization process: by using the Sommerfeld identity, we search for the optimum sampling interval, which corresponds to the minimum wavefield, evaluated for a given length filter.

The performances of the new filters obtained are compared with some well‐known filters. We find that our filters perform better for our application; that is, for the same length filters, our filters are able to calculate weaker fields.

For users working in similar applications, three sets of filters with lengths 61, 121, 241 are available from the author.
Migration methods for imaging different‐order multiples
Authors: Jiang Zhiyong , Sheng Jianming , Yu Jianhua , Schuster Gerard T. , Hornby Brian E.
Published: January 2007

Multiples contain valuable information about the subsurface, and if properly migrated can provide a wider illumination of the subsurface compared to imaging with VSP primary reflections. In this paper we review three different methods for migrating multiples. The first method is model‐based, and it is more sensitive to velocity errors than primary migration; the second method uses a semi‐natural Green's function for migrating multiples, where part of the traveltimes are computed from the velocity model, and part of the traveltimes (i.e., natural traveltimes) are picked from the data to construct the imaging condition for multiples; the third method uses cross‐correlation of traces. The last two methods are preferred in the sense that they are significantly less sensitive to velocity errors and statics because they use “natural data” to construct part of the migration imaging conditions. Compared with the interferometric (i.e., crosscorrelation) imaging method the semi‐natural Green's function method is more computationally efficient and is sometimes less prone to migration artifacts.

Numerical tests with 2‐D and 3‐D VSP data show that a wider subsurface coverage, higher‐fold and more balanced illumination of the subsurface can be achieved with multiple migration compared with migration of primary reflections only. However, there can be strong interference from multiples with different orders or primaries when multiples of high order are migrated. One possible solution is to filter primaries and different orders of multiples before migration, and another possible solution is least squares migration of all events. A limitation of multiple migration is encountered for subsalt imaging. Here, the multiples must pass through the salt body more than twice, which amplifies the distortion of the image.
Oral pharmacokinetic and pharmacodynamic effects of FTY720 in cats
Authors: DOWNES S. , CHEN Y.‐J. , KYLES A. , GREGORY C.
Published: January 2007

The aim of the study was to determine pharmacokinetic and pharmacodynamic profiles of FTY720 in cats and identify any toxic side effects. Six adult cats were used for the experimental study. Single oral dosages were tested at 0.05, 0.3 and 1.0 mg/kg. Whole blood drug concentration, total white blood cell and differential counts were monitored. Flow cytometry evaluated the effects on lymphocyte subsets. A toxicity study consisted of cats receiving a dose of 0.15 mg/kg daily for 30 days. Daily observation, physical examination and bloodwork were evaluated to assess for toxicity. All single doses resulted in ≥80% reduction in circulating lymphocytes within 12 h after administration, with the duration of lymphopenia being dose dependent. CD4+ and CD5+ T cells were specifically depleted. Peripheral neutrophils declined by approximately 70% at all dosages tested. No other toxic side effects were observed. Results of this study suggest that FTY720 is effective at inducing a peripheral lymphopenia in cats without any toxic side effects. Currently, cats appear to be the only species in which FTY720 induces a neutropenia. This study provides the foundation for future clinical transplantation trials using FTY720 in cats. By using combination therapy of FTY720 and low dose cyclosporine, the incidence of serious side effects may be reduced while still preventing allograft rejection.
Pharmacokinetics of erythromycin in nonlactating and lactating goats after intravenous and intramuscular administration
Authors: AMBROS L. , MONTOYA L. , KREIL V. , WAXMAN S. , ALBARELLOS G. , REBUELTO M. , HALLU R. , SAN ANDRES M. I.
Published: January 2007

The objectives of this work were to compare the pharmacokinetics of erythromycin administered by the intramuscular (i.m.) and intravenous (i.v.) routes between nonlactating and lactating goats and to determine the passage of the drug from blood into milk. Six nonpregnant, nonlactating and six lactating goats received erythromycin by the i.m. (15 mg/kg) and the i.v. (10 mg/kg) routes of administration. Milk and blood samples were collected at predetermined times. Erythromycin concentrations were determined by microbiological assay. Results are reported as mean ± SD. Comparison of the pharmacokinetic profiles between nonlactating and lactating animals after i.v. administration indicated that significant differences were found in the mean body clearance (8.38 ± 1.45 vs. 3.77 ± 0.83 mL/kg·h respectively), mean residence time (0.96 ± 0.20 vs. 3.18 ± 1.32 h respectively), area under curve from 0 to 12 h (AUC0−12) (1.22 ± 0.22 vs. 2.76 ± 0.58 μg·h/mL respectively) and elimination half‐life (1.41 ± 1.20 vs. 3.32 ± 1.34 h); however, onlyAUC0−12showed significant differences after the i.m. administration. Passage of erythromycin in milk was high (peak milk concentration/peak serum concentration, 2.06 ± 0.36 andAUC0−12milk/AUC0−12serum,6.9 ± 1.05 and 2.37 ± 0.61 after i.v. and i.m. administrations respectively). We, therefore, conclude that lactation affects erythromycin pharmacokinetics in goats.
Pharmacokinetics of altrenogest in horses
Authors: MACHNIK M. , HEGGER I. , KIETZMANN M. , THEVIS M. , GUDDAT S. , SCHÄNZER W.
Published: January 2007

The Federation Equestre Internationale has permitted the use of altrenogest in mares for the control of oestrus. However, altrenogest is also suspicious to misuse in competition horses for its potential anabolic effects and suppression of typical male behaviour, and thus is a controlled drug. To investigate the pharmacokinetics of altrenogest in horses we conducted an elimination study. Five oral doses of 44 μg/kg altrenogest were administered to 10 horses at a dose interval of 24 h. Following administration blood and urine samples were collected at appropriate intervals. Altrenogest concentrations were measured by liquid chromatography‐tandem mass spectrometry. The plasma levels of altrenogest reached maximal concentrations of 23–75 ng/mL. Baseline values were achieved within 3 days after the final administration. Urine peak concentrations of total altrenogest ranged from 823 to 3895 ng/mL. Twelve days after the final administration concentrations were below the limit of detection (ca 2 ng/mL).
Residues of veterinary drugs at injection sites
Authors: REEVES P. T.
Published: January 2007

Residues of veterinary drugs have potential implications for human food safety and international trade in animal‐derived food commodities. A particular concern is the slow depletion of residues of some injectable formulations from the site of administration. Licensing authorities have adopted different approaches to the human food safety assessment of injection site residues. European agencies apply the maximum residue limit (MRL) for muscle to muscle at the injection site and specify a withdrawal period sufficient to ensure the ingestion of a 300 g portion of muscle, if comprised entirely of injection site tissue, does not exceed the acceptable daily intake. The agencies in Australia, Canada and the USA also exclude injection site residues from the MRL‐setting process. These agencies evaluate the risk to consumers posed by potential acute manifestations resulting from the infrequent ingestion of injection site residues based on acute dietary exposure considerations. While all of these approaches protect the safety of consumers, the adoption of different approaches has potential implications for residue surveillance programs in the international trade in meat. In particular, when an exporting country establishes standards for residues at injection sites based on acute dietary exposure considerations and the importing country assesses these residues against the MRL for muscle, the unnecessary condemnation of meat and disruption to market access may result. The latter may represent a potential economical impost to the exporting country. An internationally harmonized approach to the risk analysis of residues of veterinary drugs at injection sites, which protects the safety of consumers and facilitates the international trade in meat, is needed.
Fow2, a Zn(II)2Cys6‐type transcription regulator, controls plant infection of the vascular wilt fungus Fusarium oxysporum
Authors: Imazaki Iori , Kurahashi Makoto , Iida Yuichiro , Tsuge Takashi
Published: January 2007

The filamentous fungus Fusarium oxysporum is a soil‐borne parasite that causes vascular wilts in a wide variety of crops by directly penetrating roots and colonizing the vascular tissue. In previous work, we generated the non‐pathogenic mutant B137 of the melon wilt pathogen F. oxysporum f. sp. melonis by using restriction enzyme‐mediated integration (REMI) mutagenesis. Molecular characterization of B137 revealed that this mutant has a single‐copy plasmid insertion in a gene, designated FOW2, which encodes a putative transcription regulator belonging to the Zn(II)2Cys6 family. The REMI mutant B137 and other FOW2‐targeted mutants completely lost pathogenicity, but were not impaired in vegetative growth and conidiation in cultures. Microscopic observation of infection behaviours of green fluorescent protein (GFP)‐marked wild‐type and mutant strains revealed that the mutants were defective in their abilities to invade roots and colonize plant tissues. FOW2 is conserved in F. oxysporum pathogens that infect different plants. The FOW2‐targeted mutants of the tomato wilt pathogen F. oxysporum f. sp. lycopersici also lost pathogenicity. Nuclear localization of Fow2 was verified using strains expressing Fow2‐GFP and GFP‐Fow2 fusion proteins. These data strongly suggest that FOW2 encodes a transcription regulator controlling the plant infection capability of F. oxysporum pathogens.
Substantive Symbols: The Attitudinal Dimension of Black Political Incorporation in Local Government
Authors: Marschall Melissa J. , Ruhil Anirudh V. S.
Published: January 2007

Traditional studies of minority incorporation focus on the redistribution of public resources that purportedly follows black gains in representation. The present study departs from this approach by focusing on the attitudinal effects of black leadership. Two research questions guide this study: To what extent do blacks' assessments of neighborhood services and conditions stem from black representation in local executive and legislative offices? Are these attitudinal effects rooted in policy and service delivery outcomes? Employing survey data from 3,000 blacks embedded in 52 cities and 53 school districts, this study reveals that blacks report higher levels of satisfaction with their neighborhood conditions, police services, and public schools when represented by blacks in city hall and on school boards and that these evaluations are most positive when improvements in local services are conspicuous. Overall, these findings extend conventional conceptualizations of substantive benefits and challenge more pessimistic accounts regarding the effects of black representation in local politics.
American Patriotism, National Identity, and Political Involvement
Authors: Huddy Leonie , Khatib Nadia
Published: January 2007

Researchers disagree over the definition, measurement, and expected political consequences of American patriotism, a situation that is fueled by the absence of a strong theoretical research foundation. We develop and evaluate a new measure of national attachment that is grounded in social identity theory (Tajfel and Turner 1979), drawing on data from three distinct sources: two studies of undergraduate students and the 1996 General Social Survey (GSS). Confirmatory factor analyses provide clear evidence that national identity is distinct from other measures of national attachment including symbolic, constructive, and uncritical patriotism, and nationalism. National identity has a number of other good measurement properties when compared to existing measures: it receives equal endorsement from conservatives and liberals (unlike most other measures which exhibit an ideological bias), develops with time spent in the United States among immigrants, and most importantly is the only measure of national attachment to predict political interest and voter turnout in both student and adult samples, consistent with the predictions of social identity theory. In that sense, the national identity measure outperforms all other measures of national attachment and provides unambiguous evidence that a strong American identity promotes civic involvement.
Competing Principals, Political Institutions, and Party Unity in Legislative Voting
Authors: Carey John M.
Published: January 2007

Almost all legislators are subordinate to party leadership within their assemblies. Institutional factors shape whether, and to what degree, legislators are also subject to pressure from other principals whose demands may conflict with those of party leaders. This article presents a set of hypotheses on the nature of competing pressures driven by formal political institutions and tests the hypotheses against a new dataset of legislative votes from across 19 different countries. Voting unity is lower where legislators are elected under rules that provide for intraparty competition than where party lists are closed, marginally lower in federal than unitary systems, and the effects on party unity of being in government differ in parliamentary versus presidential systems. In the former, governing parties are more unified than the opposition, win more, and suffer fewer losses due to disunity. In systems with elected presidents, governing parties experience no such boosts in floor unity, and their legislative losses are more apt to result from cross‐voting.
Learning about Democracy in Africa: Awareness, Performance, and Experience
Authors: Mattes Robert , Bratton Michael
Published: January 2007

Conventional views of African politics imply that Africans' political opinions are based either on enduring cultural values or their positions in the social structure. In contrast, we argue that Africans form attitudes to democracy based upon what they learn about what it is and does. This learning hypothesis is tested against competing cultural, institutional, and structural theories to explain citizens' demand for democracy (legitimation) and their perceived supply of democracy (institutionalization) with data from 12 Afrobarometer attitude surveys conducted between 1999 and 2001. A multilevel model that specifies and estimates the impacts of both individual‐ and national‐level factors provides evidence of learning from three different sources. First, people learn about the content of democracy through cognitive awareness of public affairs. Second, people learn about the consequences of democracy through direct experience of the performance of governments and (to a lesser extent) the economy. Finally, people draw lessons about democracy from national political legacies.
Daytime variability of baroreflex function in patients with obstructive sleep apnoea: implications for hypertension
Authors: Cooper V. L. , Elliott M. W. , Pearson S. B. , Taylor C. M. , Mohammed M. M. J. , Hainsworth R.
Published: January 2007

Obstructive events during sleep in patients with obstructive sleep apnoea (OSA) cause large alterations in blood pressure, and this may lead to changes in baroreflex function with implications for long‐term blood pressure control. This study examined the daytime variations in the responses to carotid baroreceptor stimulation in OSA patients. We determined the cardiac and vascular responses every 3 h between 09.00 and 21.00 h in 20 patients with OSA, using graded suctions and pressures applied to a neck collar. These responses were plotted against estimated carotid sinus pressures and, from these plots, baroreflex sensitivities and operating points were taken as the maximal slopes and the corresponding carotid sinus pressures, respectively. We found that at 09.00 h, sensitivity for the control of vascular resistance was at its lowest (−1.2 ± 0.2% mmHg−1, compared with −1.9 ± 0.3% mmHg−1 at 12.00 h, P < 0.02) and operating point for control of mean arterial pressure was at its highest (101.1 ± 5.8 mmHg, compared with 94.1 ± 5.8 mmHg at 12.00 h, P < 0.05). This is in contrast to previous data from normal subjects, in whom sensitivity was highest and operating point lowest at 09.00 h. We suggest that the higher baroreflex sensitivity and lower operating point seen in the mornings in normal subjects may provide a protective mechanism against hypertension and that this protection is absent in patients with OSA. It is possible that the reduced reflex sensitivity and increased operating point in the mornings may actually promote hypertension.
C‐type natriuretic peptide activates a non‐selective cation current in acutely isolated rat cardiac fibroblasts via natriuretic peptide C receptor‐mediated signalling
Authors: Rose R. A. , Hatano N. , Ohya S. , Imaizumi Y. , Giles W. R.
Published: January 2007

In the heart, fibroblasts play an essential role in the deposition of the extracellular matrix and they also secrete a number of hormonal factors. Although natriuretic peptides, including C‐type natriuretic peptide (CNP) and brain natriuretic peptide, have antifibrotic effects on cardiac fibroblasts, the effects of CNP on fibroblast electrophysiology have not been examined. In this study, acutely isolated ventricular fibroblasts from the adult rat were used to measure the effects of CNP (2 × 10−8m) under whole‐cell voltage‐clamp conditions. CNP, as well as the natriuretic peptide C receptor (NPR‐C) agonist cANF (2 × 10−8m), significantly increased an outwardly rectifying non‐selective cation current (NSCC). This current has a reversal potential near 0 mV. Activation of this NSCC by cANF was abolished by pre‐treating fibroblasts with pertussis toxin, indicating the involvement of Giproteins. The cANF‐activated NSCC was inhibited by the compounds Gd3+, SKF 96365 and 2‐aminoethoxydiphenyl borate. Quantitative RT‐PCR analysis of mRNA from rat ventricular fibroblasts revealed the expression of several transient receptor potential (TRP) channel transcripts. Additional electrophysiological analysis showed that U73122, a phospholipase C antagonist, inhibited the cANF‐activated NSCC. Furthermore, the effects of CNP and cANF were mimicked by the diacylglycerol analogue 1‐oleoyl‐2‐acetyl‐sn‐glycerol (OAG), independently of protein kinase C activity. These are defining characteristics of specific TRPC channels. More detailed molecular analysis confirmed the expression of full‐length TRPC2, TRPC3 and TRPC5 transcripts. These data indicate that CNP, acting via the NPR‐C receptor, activates a NSCC that is at least partially carried by TRPC channels in cardiac fibroblasts.
Thin‐filament regulation of force redevelopment kinetics in rabbit skeletal muscle fibres
Authors: Moreno‐Gonzalez Alicia , Gillis Todd E. , Rivera Anthony J. , Chase P. Bryant , Martyn Donald A. , Regnier Michael
Published: January 2007

Thin‐filament regulation of isometric force redevelopment (ktr) was examined in rabbit psoas fibres by substituting native TnC with either cardiac TnC (cTnC), a site I‐inactive skeletal TnC mutant (xsTnC), or mixtures of native purified skeletal TnC (sTnC) and a site I‐ and II‐inactive skeletal TnC mutant (xxsTnC). Reconstituted maximal Ca2+‐activated force (rFmax) decreased as the fraction of sTnC in sTnC: xxsTnC mixtures was reduced, but maximal ktr was unaffected until rFmax was <0.2 of pre‐extracted Fmax. In contrast, reconstitution with cTnC or xsTnC reduced maximal ktr to 0.48 and 0.44 of control (P < 0.01), respectively, with corresponding rFmax of 0.68 ± 0.03 and 0.25 ± 0.02 Fmax. The ktr–pCa relation of fibres containing sTnC: xxsTnC mixtures (rFmax > 0.2 Fmax) was little effected, though ktr was slightly elevated at low Ca2+ activation. The magnitude of the Ca2+‐dependent increase in ktr was greatly reduced following cTnC or xsTnC reconstitution because ktr at low levels of Ca2+ was elevated and maximal ktr was reduced. Solution Ca2+ dissociation rates (koff) from whole Tn complexes containing sTnC (26 ± 0.1 s−1), cTnC (38 ± 0.9 s−1) and xsTnC (50 ± 1.2 s−1) correlated with ktr at low Ca2+ levels and were inversely related to rFmax. At low Ca2+ activation, ktr was similarly elevated in cTnC‐reconstituted fibres with ATP or when cross‐bridge cycling rate was increased with 2‐deoxy‐ATP. Our results and model simulations indicate little or no requirement for cooperative interactions between thin‐filament regulatory units in modulating ktr at any [Ca2+] and suggest Ca2+ activation properties of individual troponin complexes may influence the apparent rate constant of cross‐bridge detachment.
Prenatal corticosterone exposure results in altered AT1/AT2, nephron deficit and hypertension in the rat offspring
Authors: Singh Reetu R. , Cullen‐McEwen Luise A. , Kett Michelle M. , Boon Wee‐Ming , Dowling John , Bertram John F. , Moritz Karen M.
Published: January 2007

Maternal treatment with the synthetic glucocorticoid, dexamethasone has been reported to result in a nephron deficit and development of hypertension in the offspring of rats. However, it is not known whether elevated maternal corticosterone (CORT), the natural glucocorticoid, has similar effects on blood pressure and nephron endowment. The present study investigated the effects of CORT (0.8 mg kg−1 day−1) administration on embryonic day 14 (E14) and E15 of pregnancy on: (1) nephron number at postnatal day 30 (PN30); (2) blood pressure at PN120; and (3) receptors of the renal renin–angiotensin system (RRAS) (AT1Ra, AT1Rb and AT2Ra) during both embryonic (E16, E20) and adolescent (PN30) life. Plasma CORT concentrations were approximately doubled 30 min after injection. Unbiased stereological analysis revealed that maternal CORT treatment resulted in a nephron deficit of 21 and 19% in male and female offspring, respectively. Mean arterial pressures were significantly elevated in offspring of both sexes from the CORT group. Real‐time PCR revealed that CORT treatment increased expression of AT1Ra and AT2R at E16, and at PN30. Expression of AT1Rb was downregulated in embryonic life but upregulated at PN30. We believe that these results are the first to demonstrate that maternal CORT treatment results in a nephron deficit and development of hypertension in the rat offspring. Changes in the RRAS may be contributing to these phenotypes. Critically, this study suggests that increased but physiological levels of the natural glucocorticoid can programme similar changes to those seen with pharmacological doses of the synthetic glucocorticoid. This may have important implications for women experiencing significant stress during pregnancy.
Cross-Species Identification of Mendel's
I
Locus
Authors: Armstead Ian , Donnison Iain , Aubry Sylvain , Harper John , Hörtensteiner Stefan , James Caron , Mani Jan , Moffet Matt , Ougham Helen , Roberts Luned , Thomas Ann , Weeden Norman , Thomas Howard , King Ian
Published: January 2007

A key gene involved in plant senescence, mutations of which partially disable chlorophyll catabolism and confer stay-green leaf and cotyledon phenotypes, has been identified in
Pisum sativum
,
Arabidopsis thaliana
, and
Festuca pratensis
by using classical and molecular genetics and comparative genomics. A stay-green locus in
F. pratensis
is syntenically equivalent to a similar stay-green locus on rice chromosome 9. Functional testing in
Arabidopsis
of a homolog of the rice candidate gene revealed (i) senescence-associated gene expression and (ii) a stay-green phenotype after RNA interference silencing. Genetic mapping in pea demonstrated cosegregation with the yellow/green cotyledon polymorphism (
I/i
) first reported by Gregor Mendel in 1866.
Live-Cell Imaging of Enzyme-Substrate Interaction Reveals Spatial Regulation of PTP1B
Authors: Yudushkin Ivan A. , Schleifenbaum Andreas , Kinkhabwala Ali , Neel Benjamin G. , Schultz Carsten , Bastiaens Philippe I. H.
Published: January 2007

Endoplasmic reticulum–localized protein-tyrosine phosphatase PTP1B terminates growth factor signal transduction by dephosphorylation of receptor tyrosine kinases (RTKs). But how PTP1B allows for RTK signaling in the cytoplasm is unclear. In order to test whether PTP1B activity is spatially regulated, we developed a method based on Förster resonant energy transfer for imaging enzyme-substrate (ES) intermediates in live cells. We observed the establishment of a steady-state ES gradient across the cell. This gradient exhibited robustness to cell-to-cell variability, growth factor activation, and RTK localization, which demonstrated spatial regulation of PTP1B activity. Such regulation may be important for generating distinct cellular environments that permit RTK signal transduction and that mediate its eventual termination.
An X Chromosome Gene,
WTX
, Is Commonly Inactivated in Wilms Tumor
Authors: Rivera Miguel N. , Kim Woo Jae , Wells Julie , Driscoll David R. , Brannigan Brian W. , Han Moonjoo , Kim James C. , Feinberg Andrew P. , Gerald William L. , Vargas Sara O. , Chin Lynda , Iafrate A. John , Bell Daphne W. , Haber Daniel A.
Published: January 2007

Wilms tumor is a pediatric kidney cancer associated with inactivation of the
WT1
tumor-suppressor gene in 5 to 10% of cases. Using a high-resolution screen for DNA copy-number alterations in Wilms tumor, we identified somatic deletions targeting a previously uncharacterized gene on the X chromosome. This gene, which we call
WTX
, is inactivated in approximately one-third of Wilms tumors (15 of 51 tumors). Tumors with mutations in
WTX
lack
WT1
mutations, and both genes share a restricted temporal and spatial expression pattern in normal renal precursors. In contrast to biallelic inactivation of autosomal tumor-suppressor genes,
WTX
is inactivated by a monoallelic “single-hit” event targeting the single X chromosome in tumors from males and the active X chromosome in tumors from females.
Responsibilities and obligations of using human research specimens transported across national boundaries
Authors: Muula A S , Mfutso-Bengo J M
Published: January 2007

Research collaboration beyond national jurisdiction is one aspect of the globalisation of health research. It has potential to complement researchers in terms of research skills, equipment and lack of adequate numbers of potential research subjects. Collaboration at an equal level of partnership though desirable, may not be practicable. Sometimes, human research specimens must be transported from one country to other. Where this occurs, there should be clear understanding between the collaborating research institutions regarding issues of access and control of the specimens as well as the duration of storage of specimens. The researchers have the duty to inform the research participants about specimen storage and transport across national boundaries. While obtaining informed consent from study subjects if specimens are to be stored beyond the life of the present study could be the ideal, there still remains significant challenges in a multi-cultural world.
Truth telling, autonomy and the role of metaphor
Authors: Kirklin D
Published: January 2007

This paper examines the potential role of metaphors in helping healthcare professionals to communicate honestly with patients and in helping patients gain a richer and more nuanced understanding of what is being explained. One of the ways in which doctors and nurses may intentionally, or unintentionally, avoid telling the truth to patients is either by using metaphors that obscure the truth or by failing to deploy appropriately powerful and revealing metaphors in their discussions. This failure to tell the truth may partly account for the observation by clinicians that patients sometimes make decisions that, from the perspective of their clinician, and given all that the clinician knows, seem unwise. For example, patients with advanced cancer may choose to undergo further, aggressive, treatment despite the fact that they are likely to accrue little or no benefit as a result. While acknowledging that the immediate task of telling patients the truth can be difficult for all those concerned, I argue that the long-term consequences of denying patients autonomy at the end of life can be harmful to patients and can leave doctors and nurses distressed and confused.
Should the precautionary principle guide our actions or our beliefs?
Authors: Peterson M
Published: January 2007

Two interpretations of the precautionary principle are considered. According to the normative (action-guiding) interpretation, the precautionary principle should be characterised in terms of what it urges doctors and other decision makers to do. According to the epistemic (belief-guiding) interpretation, the precautionary principle should be characterised in terms of what it urges us to believe. This paper recommends against the use of the precautionary principle as a decision rule in medical decision making, based on an impossibility theorem presented in Peterson (2005). However, the main point of the paper is an argument to the effect that decision theoretical problems associated with the precautionary principle can be overcome by paying greater attention to its epistemic dimension. Three epistemic principles inherent in a precautionary approach to medical risk analysis are characterised and defended.
THE LATTICE OF PRERADICALS OVER LOCAL UNISERIAL RINGS
Authors: FERNANDEZ-ALONSO ROGELIO , GAVITO SILVIA
Published: January 2007

In this paper we describe the lattice of preradicals over any local uniserial ring (equivalently, any local artinian principal ideal ring). This lattice is isomorphic to a lattice of binary sequences of length n, where n is the length of the composition series for the ring, as a left and as a right module. We prove some of its properties: it is finite having cardinality 2n, it is distributive, self-dual and it is graded having rank [Formula: see text]. We also describe the correspondent posets of irreducible, join-irreducible, prime and coprime elements.
IL-1β modulation of H,K-ATPase α-subunit gene transcription inHelicobacter pyloriinfection
Authors: Saha Arindam , Hammond Charles E. , Gooz Monika , Smolka Adam J.
Published: January 2007

Helicobacter pylori infection of the human gastric body induces hypochlorhydria by perturbing acid secretion. H. pylori inhibits parietal cell H,K-ATPase α-subunit (HKα) gene and protein expression, providing a mechanistic basis for clinical hypochlorhydria. Given that H. pylori infection increases gastric mucosal IL-1β, an acid secretory inhibitor, we investigated the role of IL-1β in H. pylori-mediated inhibition of HKα transcription. Human gastric adenocarcinoma (AGS) cells were transfected with promoter-reporter constructs containing human HKα 5′-flanking sequence deletions. IL-1β (10 ng/ml) had no effect on the transcriptional activity of six progressively shorter deletion constructs of the HKα promoter (HKα2179–HKα340) and significantly stimulated the activity of HKα206, HKα177, HKα165, and HKα102 deletion constructs (80%, 100%, 46%, and 35%, respectively). H. pylori inhibited the transcriptional activity of HKα2179, HKα206, HKα177, and HKα165; IL-1β relieved the H. pylori inhibition of HKα2179 and HKα206 activity but not HKα177 and HKα165 activity. AGS cell pretreatment with a MEK1/2 inhibitor prevented the IL-1β-mediated stimulation, but p38 and JNK pathway inhibitors did not. IL-1β mRNA levels in AGS cells were low and unaffected by H. pylori, and ELISAs of H. pylori-conditioned AGS culture media showed no measurable IL-1β secretion. These data indicate that an IL-1β-dependent cis-response element lies downstream of −206 nt in the HKα promoter and that IL-1β-mediated upregulation of HKα transcription is affected by an ERK1/2 kinase signal pathway. We conclude that an IL-1β-responsive HKα cis element positively regulates HKα gene transcription in shortened deletion constructs and that H. pylori-induced inhibition of HKα transcription is not mediated by IL-1β.