bluuebunny/crossref_metadata_2025 huggingface dataset:
Low temperature tunneling magnetoresistance on (La,Sr)MnO3∕Co junctions with organic spacer layers
Authors: Vinzelberg H. , Schumann J. , Elefant D. , Gangineni R. B. , Thomas J. , Büchner B.
Published: May 2008

This paper concerns with giant magnetoresistance (MR) effects in organic spin valves, which are realized as layered (La,Sr)MnO3 (LSMO)-based junctions with tris-(8, hydroxyquinoline) aluminum (Alq3)-spacer and ferromagnetic top layers. The experimental work was focused on the understanding of the transport behavior in this type of magnetic switching elements. The device preparation was carried out in an ultrahigh vacuum chamber equipped with a mask changer by evaporation and sputtering on SrTiO3 substrates with LSMO stripes deposited by pulsed laser technique. The field and temperature dependences of the MR of the prepared elements are studied. Spin-valve effects at 4.2K have been observed in a broad resistance interval from 50Ω to MΩ range, however, without systematic dependence on spacer layer thickness and device area. In some samples, the MR changes sign as a function of the bias voltage. The observed similarity in the bias voltages dependences of the MR in comparison with conventional magnetic tunnel junctions with oxide barriers suggests a description of the found effects within the classical tunneling concept. This assumption is also confirmed by a similar switching behavior observed on ferromagnetically contacted carbon nanotube devices. The proposed model implies the realization of the transport via local Co chains embedded in the Alq3 layer and spin dependent tunneling over barriers at the interface Co grains∕Alq3∕LSMO. The existence of conducting Co chains within the organics is supported by transmission electron microscopic∕electron energy loss spectroscopic studies on cross-sectional samples from analogous layer stacks.
Wide-view and single cell gap transflective liquid crystal display using slit-induced multidomain structures
Authors: Lu Ruibo , Ge Zhibing , Wu Shin-Tson
Published: May 2008

A wide-view transflective liquid crystal display (TR-LCD) using a single cell gap multidomain vertical alignment (MVA) cell is proposed. Unlike a conventional MVA which uses physical protrusions to form multidomain structures, our TR-LCD uses slit-induced longitudinal and fringe electric fields to generate multidomains. As a result, wide-view, high contrast ratio, and high transmittance are obtained. By varying the slit density in the transmissive and reflective regions, the optical path-length disparity between these regions can be balanced. Potential application of this TR-LCD for mobile displays is emphasized.
Temperature dependence of the interface moments in Co2MnSi thin films
Authors: Telling N. D. , Keatley P. S. , Shelford L. R. , Arenholz E. , van der Laan G. , Hicken R. J. , Sakuraba Y. , Tsunegi S. , Oogane M. , Ando Y. , Takanashi K. , Miyazaki T.
Published: May 2008

X-ray magnetic circular dichroism (XMCD) is utilized to explore the temperature dependence of the interface moments in Co2MnSi (CMS) thin films capped with aluminum. By increasing the thickness of the capping layer, we demonstrate enhanced interface sensitivity of the measurements. L21-ordered CMS films show no significant temperature dependence of either the Co or Mn interface moments. However, disordered CMS films show a decreased moment at low temperature possibly caused by increased Mn–Mn antiferromagnetic coupling. It is suggested that for ordered L21 CMS films the temperature dependence of the tunneling magnetoresistance is not related to changes in the interface moments.
Twisting of nanowires induced by anisotropic surface stresses
Authors: Wang Jian-Shan , Feng Xi-Qiao , Wang Gang-Feng , Yu Shou-Wen
Published: May 2008

Many natural and synthetic quasi-one-dimensional materials are of helical or twisting shape and understanding the physical mechanisms underlying the asymmetric shape is of both theoretical and technological significances. In this letter, we pointed out that anisotropic surface stresses present as a possible reason for the formation of some micro-/nanohelices. Using Gurtin’s theory of surface elasticity, we quantitatively investigated the twisting deformation of nanowires due to anisotropic surface stresses. The present model can also elucidate the formation of some other helical materials at micro- and nanoscales, e.g., twisting lamellae in polymer spherulites, spiraled bacteria, and flagella.
Room temperature soft ferromagnetism in the nanocrystalline form of YCo2, A well-known bulk Pauli paramagnet
Authors: Jammalamadaka S. Narayana , Sampathkumaran E. V. , Narayana Murthy V. Satya , Markandeyulu G.
Published: May 2008

The Laves phase compound YCo2 is a well-known exchange-enhanced Pauli paramagnet. We report here that, in the nanocrystalline form, this compound interestingly is an itinerant ferromagnet at room temperature with a low coercive field. The magnitude of the saturation moment (about 1μB per formula unit) is large enough to infer that the ferromagnetism is not a surface phenomenon in these nanocrystallites. Since these ferromagnetic nanocrystallites are easy to synthesize with a stable form in air, one can explore applications, particularly where the hysteresis is a disadvantage.
Taxonomic revision of Gompholobium (Leguminosae: Mirbelieae)
Authors: Chappill Jennifer A. , Wilkins Carolyn F. , Crisp Michael D.
Published: May 2008

A taxonomic revision is presented of the Australasian legume genus Gompholobium Sm. The group includes 44 species, the following six of them newly described here: Gompholobium gairdnerianum Chappill, G. glutinosum Chappill, G. karijini Chappill, G. pungens Chappill, G. roseum Chappill and G. wonganense Chappill. Gompholobium asperulum (S.Moore) Crisp is recognised here as a nomenclatural synonym of G. shuttleworthii Meisn. The taxon that has been known under the former name is renamed as Gompholobium cinereum Chappill. Gompholobium venustum R.Br. var. laeve Benth. is recognised as a distinct species, G. cyaninum Chappill, the new epithet recognising the unique blue standard and wings of this species. Gompholobium aristatum var. muticum Benth., G. aristatum var. laxum Benth. and G. virgatum var. aspalathoides (A.Cunn. ex Benth.) Benth. are all raised to specific status. Gompholobium simplicifolium (F.Muell. & Tate) Crisp is excluded.
A rationally engineered misacylating aminoacyl-tRNA synthetase
Authors: Bullock Timothy L. , Rodríguez-Hernández Annia , Corigliano Eleonora M. , Perona John J.
Published: May 2008

Information transfer from nucleic acid to protein is mediated by aminoacyl-tRNA synthetases, which catalyze the specific pairings of amino acids with transfer RNAs. Despite copious sequence and structural information on the 22 tRNA synthetase families, little is known of the enzyme signatures that specify amino acid selectivities. Here, we show that transplanting a conserved arginine residue from glutamyl-tRNA synthetase (GluRS) to glutaminyl-tRNA synthetase (GlnRS) improves the
K
M
of GlnRS for noncognate glutamate. Two crystal structures of this C229R GlnRS mutant reveal that a conserved twin-arginine GluRS amino acid identity signature cannot be incorporated into GlnRS without disrupting surrounding protein structural elements that interact with the tRNA. Consistent with these findings, we show that cumulative replacement of other primary binding site residues in GlnRS, with those of GluRS, only slightly improves the ability of the GlnRS active site to accommodate glutamate. However, introduction of 22 amino acid replacements and one deletion, including substitution of the entire primary binding site and two surface loops adjacent to the region disrupted in C229R, improves the capacity of
Escherichia coli
GlnRS to synthesize misacylated Glu-tRNA
Gln
by 16,000-fold. This hybrid enzyme recapitulates the function of misacylating GluRS enzymes found in organisms that synthesize Gln-tRNA
Gln
by an alternative pathway. These findings implicate the RNA component of the contemporary GlnRS–tRNA
Gln
complex in mediating amino acid specificity. This role for tRNA may persist as a relic of primordial cells in which the evolution of the genetic code was driven by RNA-catalyzed amino acid–RNA pairing.
Microtubule Plus-End Conformations and Dynamics in the Periphery of Interphase Mouse Fibroblasts
Authors: Zovko Sandra , Abrahams Jan Pieter , Koster Abraham J. , Galjart Niels , Mommaas A. Mieke
Published: May 2008

The plus ends of microtubules (MTs) alternate between phases of growth, pause, and shrinkage, a process called “dynamic instability.” Cryo-EM of in vitro–assembled MTs indicates that the dynamic state of the plus end corresponds with a particular MT plus-end conformation. Frayed (“ram's horn like”), blunt, and sheet conformations are associated with shrinking, pausing, and elongating plus ends, respectively. A number of new conformations have recently been found in situ but their dynamic states remained to be confirmed. Here, we investigated the dynamics of MT plus ends in the peripheral area of interphase mouse fibroblasts (3T3s) using electron microscopical and tomographical analysis of cryo-fixed, freeze-substituted, and flat-embedded sections. We identified nine morphologically distinct plus-end conformations. The frequency of these conformations correlates with their proximity to the cell border, indicating that the dynamic status of a plus end is influenced by features present in the periphery. Shifting dynamic instability toward depolymerization with nocodazole enabled us to address the dynamic status of these conformations. We suggest a new transition path from growth to shrinkage via the so-called sheet-frayed and flared ends, and we present a kinetic model that describes the chronology of events taking place in nocodazole-induced MT depolymerization.
A distance metric for a class of tree-sibling phylogenetic networks
Authors: Cardona Gabriel , Llabrés Mercè , Rosselló Francesc , Valiente Gabriel
Published: May 2008

Motivation: The presence of reticulate evolutionary events in phylogenies turn phylogenetic trees into phylogenetic networks. These events imply in particular that there may exist multiple evolutionary paths from a non-extant species to an extant one, and this multiplicity makes the comparison of phylogenetic networks much more difficult than the comparison of phylogenetic trees. In fact, all attempts to define a sound distance measure on the class of all phylogenetic networks have failed so far. Thus, the only practical solutions have been either the use of rough estimates of similarity (based on comparison of the trees embedded in the networks), or narrowing the class of phylogenetic networks to a certain class where such a distance is known and can be efficiently computed. The first approach has the problem that one may identify two networks as equivalent, when they are not; the second one has the drawback that there may not exist algorithms to reconstruct such networks from biological sequences.

Results: We present in this article a distance measure on the class of semi-binary tree-sibling time consistent phylogenetic networks, which generalize tree-child time consistent phylogenetic networks, and thus also galled-trees. The practical interest of this distance measure is 2-fold: it can be computed in polynomial time by means of simple algorithms, and there also exist polynomial-time algorithms for reconstructing networks of this class from DNA sequence data.

Availability: The Perl package Bio::PhyloNetwork, included in the BioPerl bundle, implements many algorithms on phylogenetic networks, including the computation of the distance presented in this article.

Contact:  gabriel.cardona@uib.es

Supplementary information: Some counterexamples, proofs of the results not included in this article, and some computational experiments are available at Bioinformatics online.
Characterization of clinical Clostridium difficile isolates by PCR ribotyping and detection of toxin genes in Austria, 2006–2007
Authors: Indra A. , Schmid D. , Huhulescu S. , Hell M. , Gattringer R. , Hasenberger P. , Fiedler A. , Wewalka G. , Allerberger F.
Published: May 2008

In order to assess the lethality of Clostridium difficile-associated disease (CDAD) and the PCR ribotypes prevalent in Austria, the Austrian Agency for Health and Food Safety requested isolates of C. difficile from patients in a structured but arbitrary sampling scheme. In the allocated period from February 2006 to January 2007, local hospital laboratories within each of the nine provinces were asked to submit C. difficile isolates from at least ten cases of CDAD. Confirmation of species identification, toxin detection, susceptibility testing against four antimicrobial agents and typing using a PCR ribotyping method were performed at the reference laboratory. In total, 149 isolates of putative C. difficile were submitted, from which 142 were included for study. Antimicrobial susceptibility patterns revealed resistance to clindamycin in 57 % and high-level resistance to moxifloxacin in 38 % of isolates tested. CDAD manifested as diarrhoea (including eight cases of bloody diarrhoea) in 126 cases (88.7 %), as pseudomembranous colitis in 15 cases (10.6 %) and as toxic megacolon in one case. Twelve of the 142 patients died within 30 days of specimen collection (8.45 % lethality). A lethal outcome occurred in 2/15 cases (13.3 %) when pseudomembranous colitis was present and in 10/126 cases (7.9 %) in the absence of pseudomembranous colitis or toxic megacolon. Among the 142 isolates from 25 health-care facilities, 41 PCR ribotype patterns were found. The most frequent ribotypes were AI-5 (including six lethal cases out of 26 patients), 014 (two out of 24) and 053 (one out of 24). The typing patterns demonstrated the occurrence of clusters in hospitals.
Nestedness, niche metrics and temporal dynamics of a metacommunity in a dynamic natural model system
Authors: Azeria Ermias T. , Kolasa Jurek
Published: May 2008

Prediction of extinction and colonization rates for whole species assemblages emerges as an urgent task for ecology. We hypothesized that nestedness of species assemblage reflects differential ability of species to occupy sites and of sites to support species. If correct, a nested ordering of species and sites should condense long‐term dynamics of metacommunities. To test this we characterized the differential ability of species to use habitat (niche position and niche breadth) using eight surveys of invertebrate communities inhabiting 49 tropical rock pools. We examined temporal consistency of the nested rank of species and pools, and related them to species and pool characteristics to infer temporal dynamics of species composition. Invertebrate assemblages in the rock‐pools were significantly nested and species ranks were generally preserved over time. By contrast, pool ranks were usually conserved between adjacent years only but their similarity declined with time separating surveys. The nested species‐by‐pool matrix of the first survey served as a benchmark to assess individual species and local community changed in subsequent years. As hypothesized, benchmark cells with high state occupancy probability had low extinction rates in subsequent years. Moreover, species high in the nested matrix (also with high regional occupancy probability) were better survivors and colonizers relative to species that ranked low. The year‐to‐year dynamics were similar. Species with non‐marginal niche position retained high ranks in the matrix. Yet, niche position predicted only colonization rate of species. Niche breadth and species’ nested ranking, extinction risk, or ability to colonize a pool showed no relationship. Counter to the expectation, pool ranks did not predict species extinction and colonization rates. Apparently, even in dynamic systems, regional nested pattern remains consistent and the underlying extinction and colonization dynamics appear to be largely determined by the hierarchical order among species and much less by that among sites.
Invasibility of experimental grassland communities: the role of earthworms, plant functional group identity and seed size
Authors: Eisenhauer Nico , Scheu Stefan
Published: May 2008

Invasions of natural communities by non‐indigenous species threaten native biodiversity and are currently rated as one of the most important global‐scale environmental problems. The mechanisms that make communities resistant to invasions and drive the establishment success of seedlings are essential both for management and for understanding community assembly and structure. Especially in grasslands, anecic earthworms are known to function as ecosystem engineers, however, their direct effects on plant community composition and on the invasibility of plant communities via plant seed burial, ingestion and digestion are poorly understood.

In a greenhouse experiment we investigated the impact ofLumbricus terrestris, plant functional group identity and seed size of plant invader species and plant functional group of the established plant community on the number and biomass of plant invaders. We set up 120 microcosms comprising four plant community treatments, two earthworm treatments and three plant invader treatments containing three seed size classes.

Earthworm performance was influenced by an interaction between plant functional group identity of the established plant community and that of invader species. The established plant community and invader seed size affected the number of invader plants significantly, while invader biomass was only affected by the established community. Since earthworm effects on the number and biomass of invader plants varied with seed size and plant functional group identity they probably play a key role in seedling establishment and plant community composition.

Seeds and germinating seedlings in earthworm burrows may significantly contribute to earthworm nutrition, but this deserves further attention.Lumbricus terrestrislikely behaves like a ‘farmer’ by collecting plant seeds which cannot directly be swallowed or digested. Presumably, these seeds are left in middens and become eatable after partial microbial decay. Increased earthworm numbers in more diverse plant communities likely contribute to the positive relationship between plant species diversity and resistance against invaders.
Asking the right questions in the right way: the need for a shift in research on psychological treatments for addiction
Authors: Orford Jim
Published: May 2008

Aim  To identify possible reasons for the disappointingly negative results of methodologically rigorous controlled trials of psychological treatments in the addictions field.

Method  A selective overview of the literature on addictive behaviour change.

Findings  Eight failings of existing research are described: failing to account for the outcome equivalence paradox; neglecting relationships in favour of techniques; failing to integrate treatment research and research on unaided change; imposing an inappropriate time‐scale on the change process; failing to take a systems or social network view; ignoring therapists' tacit theories; not including the patient's view; and displaying an ignorance of modern developments in the philosophy of science.

Conclusion  Treatment research has been asking the wrong questions in the wrong way. Three necessary shifts in ways of conducting research are proposed: (i) the field should stop studying named techniques and focus instead on change processes; (ii) change processes should be studied within the broader, longer‐acting systems of which treatment is part; and (iii) science in the field should be brought up to date by acknowledging a variety of sources of useful knowledge.
Do acamprosate or naltrexone have an effect on daily drinking by reducing craving for alcohol?
Authors: Richardson Kylie , Baillie Andrew , Reid Sophie , Morley Kirsten , Teesson Maree , Sannibale Claudia , Weltman Martin , Haber Paul
Published: May 2008

Aim  To explore the effect of acamprosate and naltrexone on craving and alcohol consumption in the treatment of alcohol dependence.

Design  A randomized, double‐blind, single‐dummy, placebo‐controlled trial.

Setting  Three treatment centres in Sydney, Australia.

Participants  A total of 169 alcohol‐dependent subjects were given naltrexone (50 mg/day), acamprosate (1998 mg/day) or placebo for 12 weeks, in conjunction with manualized medication compliance therapy.

Intervention  During the course of the trial, participants kept a daily diary which included the number of standard drinks they consumed and their peak craving for alcohol that day rated on a 0–10 scale.

Measurements  Subjective ratings of daily craving and daily drinking for the first 6 weeks of treatment.

Findings  Mixed/hierarchical linear models were employed on an intention‐to‐treat basis. Analyses revealed that craving was a significant predictor of daily drinking and baseline levels of depression were the best predictor of daily craving. There was no significant improvement in model fit when treatment group was added both in models of daily craving and daily drinking. Daily alcohol consumption was best predicted by a model incorporating baseline dependence and depression scores, and daily craving, entered as a time‐varying covariate. However, there was a significant craving × time × treatment interaction (t = −3.365, df = 4413.712, P < 0.001), suggesting that at higher levels of craving drinking was reduced at a significantly greater rate with naltrexone compared to acamprosate.

Conclusions  Naltrexone had a greater effect on drinking when craving was high. These results support the role of naltrexone in reducing craving when that craving is highly salient. The role of acamprosate in reducing craving was not supported by these findings.
What did you drink yesterday? Public health relevance of a recent recall method used in the 2004 Australian National Drug Strategy Household Survey
Authors: Stockwell Tim , Zhao Jinhui , Chikritzhs Tanya , Greenfield Tom K.
Published: May 2008

Aim To (i) compare the Yesterday method with other methods of assessing alcohol use applied in the 2004 Australian National Drug Strategy Household Survey (NDSHS) in terms of extent of under‐reporting of actual consumption assessed from sales data; and (ii) illustrate applications of the Yesterday method as a means of variously measuring the size of an Australian ‘standard drink’, the extent of risky/high‐risk alcohol use, unrecorded alcohol consumption and beverage‐specific patterns of risk in the general population.

Setting The homes of respondents who were eligible and willing to participate.

Participants A total of 24 109 Australians aged 12 years and over.

Design The 2004 NDSHS assessed drug use, experiences and attitudes using a ‘drop and collect’ self‐completion questionnaire with random sampling and geographic (State and Territory) and demographic (age and gender) stratification.

Measures Self‐completion questionnaire using quantity–frequency (QF) and graduated‐frequency (GF) methods plus two questions about consumption ‘yesterday’: one in standard drinks, another with empirically based estimates of drink size and strength.

Results The Yesterday method yielded an estimate of 12.8 g as the amount of ethanol in a typical Australian standard drink (versus the official 10 g). Estimated coverage of the 2003–04 age 12+ years per‐capita alcohol consumption in Australia (9.33 ml of ethanol) was 69.17% for GF and 64.63% for the QF when assuming a 12.8 g standard drink. Highest coverage of 80.71% was achieved by the detailed Yesterday method. The detailed Yesterday method found that 60.1% of Australian alcohol consumption was above low‐risk guidelines; 81.5% for 12–17‐year‐olds, 84.8% for 18–24‐year‐olds and 88.8% for Indigenous respondents. Spirit‐based drinks and regular strength beer were most likely to be drunk in this way, low‐ and mid‐strength beer least likely.

Conclusions Compared to more widely used methods, the Yesterday method minimizes under‐reporting of overall consumption and provides unique data of public health significance. It also provides an empirical basis for taxing alcoholic beverages in accordance with their contributions to harm and can be used to complement individual‐level measures such as QF and GF.
Use of an anti‐CD16 antibody for in vivo depletion of natural killer cells in rhesus macaques
Authors: Choi Elisa I. , Wang Rijian , Peterson Lauren , Letvin Norman L. , Reimann Keith A.
Published: May 2008

Non‐human primates serve as key animal models for a variety of viral infections. To evaluate the contribution of natural killer (NK) cells to the immune‐mediated control of these viruses in macaque monkeys, we have described a method for depleting NK cells in vivo by administration of anti‐human CD16 mouse monoclonal antibody. Using a fluorometric NK‐cell cytotoxicity assay, we show that most NK‐cell cytotoxicity in rhesus monkey peripheral blood mononuclear cells resides in the CD16+ and/or CD159A+ subset of lymphocytes. The anti‐human CD16 antibody, 3G8, binds to subsets of rhesus monkey lymphocytes and monocytes but not to neutrophils. Intravenous administration of 10–50 mg/kg of 3G8 to normal rhesus monkeys resulted in anti‐CD16 antibody persistence in the plasma for 1–3 weeks. This treatment also depleted 80–90% of CD3– CD159A+ lymphocytes, putative NK cells, from blood for at least 1 week and was associated with the loss of NK‐cell cytotoxicity when evaluated by in vitro assays. Using this method, transient depletion of NK cells from two rhesus monkeys chronically infected with simian immunodeficiency virus failed to cause changes in virus replication. These studies describe a non‐human primate model for in vivo NK‐cell depletion and suggest a limited role for cytotoxic CD16+ NK cells in controlling AIDS virus replication during chronic infection.
Effect of SIVmac infection on plasmacytoid and CD1c+ myeloid dendritic cells in cynomolgus macaques
Authors: Malleret Benoît , Karlsson Ingrid , Manéglier Benjamin , Brochard Patricia , Delache Benoît , Andrieu Thibault , Muller‐Trutwin Michaela , Beaumont Tim , McCune Joseph M. , Banchereau Jacques , Le Grand Roger , Vaslin Bruno
Published: May 2008

Dendritic cells (DCs) are known to be essential for the induction and regulation of immune responses. Non‐human primates are essential in biomedical research and contribute to our understanding of the involvement of DCs in human infectious diseases. However, no direct single‐platform method for quantifying DC precursors has yet been optimized in macaques to give accurate absolute blood counts of these rare‐event cell populations in the blood. We adapted a rapid whole‐blood assay for the absolute quantification of DCs in cynomolgous macaques by four‐colour flow cytometry, using a single‐platform assay compatible with human blood. Cynomolgus macaque plasmacytoid DCs (pDCs) and CD1c+ myeloid DCs (CD1c+ mDCs) were quantified in the blood of 34 healthy macaques and the results obtained were compared with those for blood samples from 11 healthy humans. In addition, circulating absolute numbers of pDCs were quantified in cynomolgus macaques chronically infected with SIVmac. During infection, pDC counts decreased whereas circulating CD1c+ mDC counts increased. Information regarding absolute pDC and mDC counts in non‐human primates may improve our understanding of the role of these cells in SIV/HIV infection and in other infectious diseases.
Population genetic structure of Chilo suppressalis (Walker) (Lepidoptera: Crambidae): strong subdivision in China inferred from microsatellite markers and mtDNA gene sequences
Authors: MENG XIANG‐FENG , SHI MIN , CHEN XUE‐XIN
Published: May 2008

Chilo suppressalis (Walker) displays significant geographical differences in ecological preference that may be congruent with patterns of molecular variation. To test this, we collected and analysed 381 individuals of this species from cultivated rice at 18 localities in China during the rice‐growing season of 2005–2006. We used four microsatellite DNA markers and four mitochondrial DNA gene fragments. We found that this species is highly differentiated, coupled with an estimated population expansion date of at least 60 000 bp. Phylogenetic analyses, Bayesian clustering, and phylogeographical analyses of statistical parsimony haplotype network consistently divided the populations into three clades: a central China (CC) clade, a northern plus northeastern China (NN) clade and a southwestern China (SW) clade. Analysis of molecular variance indicated a high level of geographical differentiation at different hierarchical levels [FST for microsatellite markers, COI, COII, 16S and ND1 is 0.06004 (P < 0.0001), 0.27607 (P < 0.0001), 0.22949 (P < 0.0001), 0.19485 (P < 0.0001) and 0.29285 (P < 0.0001), respectively]. Isolation by distance appeared among the samples from within China (r = 0.404, P = 0.0002); Nem values estimated using a coalescent‐based method were small (< 2 migrants per generation), suggesting that the observed levels of differentiation are a result of migration–drift equilibrium. Our results imply that the genetic differentiation of this borer, which is approximately in accordance with its observed number of generations per year in different Chinese geographical regions, is probably attributed to climatic and/or geological events (e.g. the last glacial maximum) and subsequently strengthened by the domestication of rice.
Inferring the evolutionary history ofDrosophila americanaandDrosophila novamexicanausing a multilocus approach and the influence of chromosomal rearrangements in single gene analyses
Authors: MORALES‐HOJAS RAMIRO , VIEIRA CRISTINA P , VIEIRA JORGE
Published: May 2008

The evolutionary history of closely related organisms can prove sometimes difficult to infer. Hybridization and incomplete lineage sorting are the main concerns; however, genome rearrangements can also influence the outcome of analyses based on nuclear sequences. In the present study, DNA sequences from 12 nuclear genes, for which the approximate chromosomal locations are known, have been used to estimate the evolutionary history of two forms ofDrosophila americana(Drosophila americana americanaandDrosophila americana texana) andDrosophila novamexicana(virilisgroup of species). The phylogenetic analysis of the combined data set resulted in a phylogeny showing reciprocal monophyly forD. novamexicanaandD. americana. Single gene analyses, however, resulted in incongruent phylogenies influenced by chromosomal rearrangements. Genetic differentiation estimates indicated a significant differentiation between the two species for all genes. WithinD. americana, however, there is no evidence for differentiation between the chromosomal forms except at genes located near theX/4fusion andXcinversion breakpoint. Thus, the specific status ofD. americanaandD. novamexicanais confirmed, but there is no overall evidence for genetic differentiation betweenD. a. americanaandD. a. texana, not supporting a subspecific status. Based on levels of allele and nucleotide diversity found in the strains used, it is proposed thatD. americanahas had a stable, large population during the recent past whileD. novamexicanahas speciated from a peripheral southwestern population having had an ancestral small effective population size. The influence of chromosomal rearrangements in single gene analyses is also examined.
Effects of choke disease in the grassBrachypodium phoenicoides
Authors: Zabalgogeazcoa I. , Ciudad A. García , Leuchtmann A. , Vázquez de Aldana B. R. , Criado B. García
Published: May 2008

Using phenotypic and molecular characters, as well as mating compatibility tests, the fungus causing choke disease inBrachypodium phoenicoideswas identified asEpichloë typhina. A three year field experiment conducted with infected and uninfected plants of a single clone ofB. phoenicoidesshowed no significant differences in biomass production during their vegetative growth stage, but the content of calcium, magnesium and manganese was significantly greater, and that of sodium was significantly lower in infected plants compared to uninfected plants. Infected plants produced up to twice as many reproductive tillers as healthy plants, but their reproductive tissue biomass was significantly smaller than that of healthy plants, because tiller development was arrested by choke forming stromata.
Cannabis and psychiatric disorders: it is not only addiction
Authors: Leweke F. Markus , Koethe Dagmar
Published: May 2008

Since the discovery of the endocannabinoid system, a growing body of psychiatric research has emerged focusing on the role of this system in major psychiatric disorders like schizophrenia (SCZ), bipolar disorder (BD), major depression and anxiety disorder. Continuing in the line of earlier epidemiological studies, recent replication studies indicate that frequent cannabis use doubles the risk for psychotic symptoms and SCZ. Further points of clinical research interest are alterations of endocannabinoids and their relation to symptoms as well as postmortem analyses of cannabinoid CB1 receptor densities in SCZ. A possible neurobiological mechanism for the deleterious influence of cannabis use in SCZ has been suggested, involving the disruption of endogenous cannabinoid signaling and functioning. Even though the number of studies is still limited for affective and anxiety disorders, previous results suggest these diseases to be exciting objectives of cannabinoid‐associated research. Therefore, it became apparent that cannabis use is not only frequent in patients suffering from BD, but that it also induces manic symptoms in this group. In addition, prior antipsychotic treatment decreased the numerical density of CB1 immunoreactive glial cells in bipolar patients. Although the data on the influence of cannabis use on the development of major depression is controversial, cannabinoid compounds could display a new class of medication, as suggested by the antidepressive effects of the fatty acid amino hydrolase inhibitor URB597 in animal models. With numerous open questions and controversial results, further research is required to specify and extend the findings in this area, which provides a promising target for novel pharmacotherapeutic interventions.
Genetic (co)variances and breeding value estimation of Gompertz growth curve parameters in Finnish Yorkshire boars, gilts and barrows
Authors: Koivula M. , Sevón‐Aimonen M.‐L. , Strandén I. , Matilainen K. , Serenius T. , Stalder K.J. , Mäntysaari E.A.
Published: May 2008

This paper’s objectives were to estimate the genetic (co)variance components of the Gompertz growth curve parameters and to evaluate the relationship of estimated breeding values (EBV) based on average daily gain (ADG) and Gompertz growth curves. Finnish Yorkshire central test station performance data was obtained from the Faba Breeding (Vantaa, Finland). The final data set included 121 488 weight records from 10 111 pigs. Heritability estimates for the Gompertz growth parameters mature weight (α), logarithm of mature weight to birth weight ratio (β) and maturation rate (κ) were 0.44, 0.55 and 0.31, respectively. Genotypic and phenotypic correlations between the growth curve parameters were high and mainly negative. The only positive relationship was found between α and β. Pearson and Spearman rank correlation coefficients between EBV for ADG and daily gain calculated from Gompertz growth curves were 0.79. The Spearman rank correlation between the sire EBV for ADG and Gompertz growth curve parameter‐based ADG for all sires with at least 15 progeny was 0.86. Growth curves differ significantly between individuals and this information could be utilized for selection purposes when improving growth rate in pigs.
A male linkage map constructed for QTL mapping in Spanish Churra sheep
Authors: Gutiérrez‐Gil B. , Arranz J.J. , El‐Zarei M.F. , Álvarez L. , Pedrosa S. , San Primitivo F. , Bayón Y.
Published: May 2008

A male ovine linkage map has been constructed on the basis of 11 half‐sib families of a commercial population of Spanish Churra sheep as part of a genome scan for quantitative trait loci mapping. A total of 1421 daughters and their sires were genotyped for 182 microsatellite markers evenly distributed along the ovine autosomes. A total of 259 192 genotypes were obtained, generating an average of 669 informative meioses per marker. An autosomal genome length of 3262 cM was estimated for the Churra population with a mean marker interval of 17.86 cM. Our map represents an approximate 90% coverage of the autosomal ovine genome and constitutes a useful tool for the genetic dissection of complex traits in this breed. General agreement was found between the Churra map and other published maps for sheep, despite certain length discrepancies.
Mixed Infection of Two Begomoviruses in Malvastrum coromandelianum in Fujian, China
Authors: Yang C. , Jia S. , Liu Z. , Cui G. , Xie L. , Wu Z.
Published: May 2008

Virus isolates were obtained from three Malvastrum coromandelianum plants showing vein thickening symptoms in Fujian Province, China. A fragment of approximately 500 bp was amplified from all the samples by PCR using the special degenerate primer pair PA/PB for begomoviruses. Sequence differences among the partial DNA‐A fragments revealed that all three samples contained two virus isolates. Isolate I and isolate II share the highest nucleotide sequence identity (98–99%), respectively, with Malvastrum leaf curl Guangdong virus (MLCuGdV) and Ageratum yellow vein virus (AYVV). The complete nucleotide sequences of Fs1 and Fs2 isolates representing each virus were determined to be 2741 and 2756 nucleotides, respectively. Alignment and phylogenetic analysis showed that the complete DNA‐A sequences of Fs1 and Fs2 were most closely to those of MLCuGdV (AM503104) and AYVV (AB100305), with 90.4% and 93.3% nucleotide sequence identity, respectively. Fs1 and Fs2 are considered therefore to be isolates of MLCuGdV and AYVV, respectively. This is the first report of AYVV in M. coromandelianum.
Pathogenic Variability of Isolates of Pseudocercospora griseola, the Cause of Common Bean Angular Leaf Spot, and its Implications for Resistance Breeding
Authors: E Silva Kaesel Jackson Damasceno , De Souza Elaine Aparecida , Sartorato Aloisio , De Souza Freire Cassius nonato
Published: May 2008

The pathogenic variability was evaluated of 48 Pseudocercospora griseola isolates collected in the State of Minas Gerais, Brazil. Isolates were inoculated to a set of 12 international differential cultivars in a greenhouse. Ten pathotypes (55‐15, 63‐7, 63‐15, 63‐23, 63‐25, 63‐27, 63‐31, 63‐47, 63‐55 and 63‐63) were identified, showing the great pathogenic variability of this fungus in Minas Gerais State. Pathotypes 55‐15, 63‐15, 63‐25 and 63‐27 had not previously been reported in the State. Of the 48 isolates, all except pathotype 55‐1547 induced a compatible reaction with all cultivars from the Andean group. Isolates were highly pathogenic in both Andean and Mesoamerican cultivars, thus being classified as Mesoamerican pathotypes. Pathotype 63‐63 was the most widespread, and overcame the resistance genes present in all differential cultivars.
Black tea and health
Authors: Ruxton C. H. S.
Published: May 2008

Summary Tea is the second most consumed beverage in the world after water. Health benefits have been associated with tea drinking, including a lower risk of coronary heart disease (CHD) and cancer, and protection against dental caries and bone loss. It is likely that these benefits relate to the high polyphenol content of tea and how these polyphenols are metabolised and used by the body. In contrast, concern has arisen about the impact of tea on hydration and iron status, and the role of tea as a source of caffeine. This article updates an earlier systematic review by including more recent published evidence on the potential role of black tea in human health. While it is clear fromin vitroand animal research that tea polyphenols act as antioxidants and have a beneficial effect on many biochemical processes in the body via a range of complex mechanisms, findings from epidemiological studies and the few available human intervention studies have been contradictory. Reasons for this are explored, including the influence of lifestyle factors other than tea consumption on cancer or CHD risk. The clearest consistent evidence points to an association between tea consumption, in excess of three cups per day, and a reduced risk of myocardial infarction. More human research is needed to draw conclusions about cancer and other markers of CHD. There was no consistent evidence pointing to a detrimental effect of tea drinking on hydration, bone health or iron status. The caffeine content of tea was modest compared with other sources and was unlikely to have an adverse effect on health within an intake range of 1 to 8 cups of tea per day.
Doubly labelled water for the measurement of total energy expenditure in man – progress and applications in the last decade
Authors: Bluck L. J. C.
Published: May 2008

Summary  The doubly labelled water method for the measurement of total energy expenditure is a methodology that is still maturing. Over the last 10 years, the number of publications describing its exploitation in man has remained roughly constant, at a rate of about 50 per annum. During this time, the laboratory techniques used have become more refined, particularly in the measurement of deuterium enrichment. This article details the methodological advances which have been made and presents a brief review of some recent applications.
Trade Unions, Union Learning Representatives and Employer‐Provided Training in Britain
Authors: Hoque Kim , Bacon Nicolas
Published: May 2008

This article provides an empirical assessment of the relationship between trade union recognition, union density, union learning representatives (ULRs) and employer‐provided training in British workplaces using linked employer–employee data from the 2004 Workplace Employment Relations Survey. The results suggest that the relationship between union recognition and training is, at best, weak. We find no consistent relationship between union density and training or between the presence of ULRs and training. We do, however, find some evidence of greater equality in the distribution of training in ULR workplaces than in other workplaces.
A DIAGNOSTIC TEST FOR NONLINEAR SERIAL DEPENDENCE IN TIME SERIES FITTING ERRORS
Authors: Ashley Richard A. , Patterson Douglas M. , Hinich Melvin J.
Published: May 2008

Abstract.Time series analysts have begun to consider the applicability of nonlinear models. In order for nonlinear models to be accepted by practitioners, practicai tests must be avilable to test for the presence of nonlinearity in both raw time series and in the residuals from fitted models. A diagnostic test, based on the bispectrum, for the presence of nonlinear serial dependence in these time series is investigated here using artificial data. Detection of such nonlinear dependence is taken to indicate that nonlinear modelling methods are necessary. The theory behind the test is reviewed and simulations driven by pseudorandom numbers are presented for a variety of models and sample sizes. The simulations indicate that the test has substantial power for many models. In addition, theoretical and empirical results are presented which show that the bispectral diagnostic test is equally powerful for both the source series and for the fitting errors from a line& model. Thus, while the test is suitable for use as a diagnostic test on the fitting errors of linear time series models, prior linear modeling of the time series is not required.
ON ESTIMATING THRESHOLDS IN AUTOREGRESSIVE MODELS
Authors: Chan K. S. , Tong H.
Published: May 2008

Abstract.The problem of estimating the threshold parameter, i.e., the change point, of a threshold autoregressive model is studied. By introducing smoothness into the model, sampling properties of the conditional least‐squares estimate may be obtained. Artificial and real data are used for illustrations.
COMPARISON OF SOME NON‐LINEAR AUTOREGRESSIVE PROCESSES
Authors: Högnäs Göran
Published: May 2008

Abstract. We investigate autoregressive processes {Xn} ({Y“}) satisfying Xn+1=Λ(Xn) + Zn+1(Yn+1=μ(Yn) + Zn+1), n = 0, 1, 2, …, where Λ and μ are odd increasing functions and the Zn‘s are i.i.d. with unimodal symmetric distribution. The process {|Xn|} is then stochastically monotone on [0, ∞). If |Λ| ≤ |μ| then |Xn is stochastically dominated by |Yn| for n = 1, 2, …. Some related asymptotic properties, e.g., stationary distributions, are also discussed.
STATE TRANSITION SPECIFICATION IN STATE‐SPACE MODELS
Authors: de Jong Piet
Published: May 2008

Abstract.This note investigates an approach to state transition specification in statespace models. The approach generalizes the procedure whereby first or higher order differences in the state are modelled as white noise.
Expressive Perception as Projective Imagining
Authors: NOORDHOF PAUL
Published: May 2008

Abstract: I argue that our experience of expressive properties (such as the joyfulness or sadness of a piece of music) essentially involvesthe sensuous imagination (through simulation) of an emotion‐guided process which would result in the production of the properties which constitute the realisation of the expressive properties experienced. I compare this proposal with arousal theories, Wollheim’s Freudian account, and other more closely related theories appealing to imagination such as Kendall Walton’s. I explain why the proposal is most naturally developed in terms of simulation and briefly comment upon the impact of work on cross‐cultural perception of facial expression, modularity and autism for the proposal.
The Challenges of Pursuing Cluster Policy in the Congested State
Authors: BURFITT ALEX , MACNEILL STEWART
Published: May 2008

In recent years cluster policy has become a central component of regional economic development strategy across many European economies. However, concerns are now emerging over the content and quality of some of these initiatives. Given the prevalence of the approach, these apprehensions are non‐trivial and have significant implications with regard to the value and contribution of regional economic development. Here we examine the extent to which weaknesses in the theoretical and methodological underpinnings of the cluster approach may have acted in combination with pressures generated by the ‘congested state’ to produce a number of difficulties. The essay explores the nature, challenges and weaknesses of cluster policy in the context of the demands created by multi‐level and multi‐actor governance frameworks. We conclude that, irrespective of whether cluster policy is the appropriate choice as an economic development tool in any particular regional or economic circumstance, its selection always necessitates prior consideration of the institutional capacity needed to meet the governance challenges that it creates.

Resumé

La ‘politique des clusters’ est récemment devenue une composante essentielle de la stratégie de développement économique régional dans de nombreux pays d’Europe. Toutefois, des questions se posent actuellement quant à la teneur et à la qualité de certaines de ces initiatives. L’approche étant souvent adoptée, ces appréhensions, dignes d’intérêt, ont d’importantes répercussions sur la valeur et la contribution du développement économique régional. Cette étude examine dans quelle mesure les faiblesses des bases théoriques et méthodologiques de l’approche des ‘clusters’, combinées aux pressions imposées par un « Etat congestionné », peuvent avoir généré plusieurs difficultés. Sont explorés la nature, les défis et les faiblesses de la politique des clusters dans le cadre des exigences suscitées par un environnement de gouvernance à plusieurs niveaux impliquant plusieurs acteurs. En conclusion, que la politique des clusters soit ou non l’option à choisir en tant qu’outil d’expansion économique dans une situation régionale ou économique donnée, son choix exige toujours une étude préalable de la capacité institutionnelle nécessaire pour résoudre les problèmes de gouvernance qu’il crée.