bluuebunny/crossref_metadata_2025 huggingface dataset:
Modulating activity in the motor cortex affects performance for the two hands differently depending upon which hemisphere is stimulated
Authors: Vines Bradley W. , Nair Dinesh , Schlaug Gottfried
Published: October 2008

We modulated neural excitability in the human motor cortex to investigate behavioral effects for both hands. In a previous study, we showed that decreasing excitability in the dominant motor cortex led to a decline in performance for the contralateral hand and an improvement for the ipsilateral hand; increasing excitability produced the opposite effects. Research suggests that the ipsilateral effects were mediated by interhemispheric inhibition. Physiological evidence points to an asymmetry in interhemispheric inhibition between the primary motor cortices, with stronger inhibitory projections coming from the dominant motor cortex. In the present study, we examined whether there is a hemispheric asymmetry in the effects on performance when modulating excitability in the motor cortex. Anodal and cathodal transcranial direct current stimulation were applied to the motor cortex of 17 participants, targeting the non‐dominant hemisphere on one day and the dominant hemisphere on another day, along with one sham session. Participants performed a finger‐sequence coordination task with each hand before and after stimulation. The dependent variable was calculated as the percentage of change in the number of correct keystrokes. We found that the effects of transcranial direct current stimulation depended upon which hemisphere was stimulated; modulating excitability in the dominant motor cortex significantly affected performance for the contralateral and ipsilateral hands, whereas modulating excitability in the non‐dominant motor cortex only had a significant impact for the contralateral hand. These results provide evidence for a hemispheric asymmetry in the ipsilateral effects of modulating excitability in the motor cortex and may be important for clinical research on motor recovery.
Progressive loss of PAX6, TBR2, NEUROD and TBR1 mRNA gradients correlates with translocation of EMX2 to the cortical plate during human cortical development
Authors: Bayatti Nadhim , Sarma Subrot , Shaw Christopher , Eyre Janet A. , Vouyiouklis Demetrius A. , Lindsay Susan , Clowry Gavin J.
Published: October 2008

The transcription factors Emx2 and Pax6 are expressed in the proliferating zones of the developing rodent neocortex, and gradients of expression interact in specifying caudal and rostral identities. Pax6 is also involved in corticoneurogenesis, being expressed by radial glial progenitors that give rise to cells that also sequentially express Tbr2, NeuroD and Tbr1, genes temporally downstream of Pax6. In this study, using in situ hybridization, we analysed the expression of EMX2, PAX6, TBR2, NEUROD and TBR1 mRNA in the developing human cortex between 8 and 12 postconceptional weeks (PCW). EMX2 mRNA was expressed in the ventricular (VZ) and subventricular zones (SVZ), but also in the cortical plate, unlike in the rodent. However, gradients of expression were similar to that of the rodent at all ages studied. PAX6 mRNA expression was limited to the VZ and SVZ. At 8 PCW, PAX6 was highly expressed rostrally but less so caudally, as has been seen in the rodent, however this gradient disappeared early in corticogenesis, by 9 PCW. There was less restricted compartment‐specific expression of TBR2, NEUROD and TBR1 mRNA than in the rodent, where the gradients of expression were similar to that of PAX6 prior to 9 PCW. The gradient disappeared for TBR2 by 10 PCW, and for NEUROD and TBR1 by 12 PCW. These data support recent reports that EMX2 but not PAX6 is more directly involved in arealization, highlighting that analysis of human development allows better spatio‐temporal resolution than studies in rodents.
Pavlovian fear conditioning as a behavioral assay for hippocampus and amygdala function: cautions and caveats
Authors: Maren Stephen
Published: October 2008

Pavlovian fear conditioning has become an important model for investigating the neural substrates of learning and memory in rats, mice and humans. The hippocampus and amygdala are widely believed to be essential for fear conditioning to contexts and discrete cues, respectively. Indeed, this parsing of function within the fear circuit has been used to leverage fear conditioning as a behavioral assay of hippocampal and amygdala function, particularly in transgenic mouse models. Recent work, however, blurs the anatomical segregation of cue and context conditioning and challenges the necessity for the hippocampus and amygdala in fear learning. Moreover, nonassociative factors may influence the performance of fear responses under a variety of conditions. Caution must therefore be exercised when using fear conditioning as a behavioral assay for hippocampal‐ and amygdala‐dependent learning.
Coastal Synechococcus metagenome reveals major roles for horizontal gene transfer and plasmids in population diversity
Authors: Palenik B. , Ren Q. , Tai V. , Paulsen I. T.
Published: October 2008

The extent to which cultured strains represent the genetic diversity of a population of microorganisms is poorly understood. Because they do not require culturing, metagenomic approaches have the potential to reveal the genetic diversity of the microbes actually present in an environment. From coastal California seawater, a complex and diverse environment, the marine cyanobacteria of the genus Synechococcus were enriched by flow cytometry‐based sorting and the population metagenome was analysed with 454 sequencing technology. The sequence data were compared with model Synechococcus genomes, including those of two coastal strains, one isolated from the same and one from a very similar environment. The natural population metagenome had high sequence identity to most genes from the coastal model strains but diverged greatly from these genomes in multiple regions of atypical trinucleotide content that encoded diverse functions. These results can be explained by extensive horizontal gene transfer presumably with large differences in horizontally transferred genetic material between different strains. Some assembled contigs showed the presence of novel open reading frames not found in the model genomes, but these could not yet be unambiguously assigned to a Synechococcus clade. At least three distinct mobile DNA elements (plasmids) not found in model strain genomes were detected in the assembled contigs, suggesting for the first time their likely importance in marine cyanobacterial populations and possible role in horizontal gene transfer.
Distribution of the uncultured protist MAST‐4 in the Indian Ocean, Drake Passage and Mediterranean Sea assessed by real‐time quantitative PCR
Authors: Rodríguez‐Martínez Raquel , Labrenz Matthias , Del Campo Javier , Forn Irene , Jürgens Klaus , Massana Ramon
Published: October 2008

Molecular surveys of marine picoeukaryotes have revealed a large number of sequences unrelated to cultured organisms, such as those forming the marine stramenopile (MAST)‐4 clade. Recent FISH (fluorescent in situ hybridization) data have shown that MAST‐4 cells are uncultured heterotrophic flagellates of 2–3 μm in size that have a global distribution in non‐polar marine waters. However, FISH is time‐consuming and hard to apply to the many samples generated during oceanographic cruises, so we developed a real‐time quantitative polymerase chain reaction (Q‐PCR) protocol to determine rapidly the abundance of this group using environmental DNA. We designed a primer set targeting the 18S rRNA genes (rDNA) of MAST‐4 and optimized and calibrated the Q‐PCR protocol using a plasmid with the target sequence as insert. The Q‐PCR was then applied to quantify MAST‐4 rDNA molecules along three marine transects, longitudinal in the Indian Ocean, latitudinal in the Drake Passage and coastal–offshore in the Mediterranean Sea, and to a temporal study in a Mediterranean Sea coastal station. MAST‐4 was detected in all samples processed (averaged abundances between 500 and 1000 rDNA molecules ml−1) except in mesopelagic and Antarctic samples, where it was virtually absent. In general, it was more abundant in the coast than offshore and in the deep chlorophyll maximum than at surface. A comparison of Q‐PCR and FISH signals in well‐controlled microbial incubations indicated that MAST‐4 cells have around 30 copies of the rDNA operon. This Q‐PCR assay quickly yielded quantitative data of uncultured MAST‐4 cells and confirmed their wide distribution and putative ecological importance.
Linking microbial oxidation of arsenic with detection and phylogenetic analysis of arsenite oxidase genes in diverse geothermal environments
Authors: Hamamura N. , Macur R. E. , Korf S. , Ackerman G. , Taylor W. P. , Kozubal M. , Reysenbach A.‐L. , Inskeep W. P.
Published: October 2008

The identification and characterization of genes involved in the microbial oxidation of arsenite will contribute to our understanding of factors controlling As cycling in natural systems. Towards this goal, we recently characterized the widespread occurrence of aerobic arsenite oxidase genes (aroA‐like) from pure‐culture bacterial isolates, soils, sediments and geothermal mats, but were unable to detect these genes in all geothermal systems where we have observed microbial arsenite oxidation. Consequently, the objectives of the current study were to measure arsenite‐oxidation rates in geochemically diverse thermal habitats in Yellowstone National Park (YNP) ranging in pH from 2.6 to 8, and to identify corresponding 16S rRNA and aroA genotypes associated with these arsenite‐oxidizing environments. Geochemical analyses, including measurement of arsenite‐oxidation rates within geothermal outflow channels, were combined with 16S rRNA gene and aroA functional gene analysis using newly designed primers to capture previously undescribed aroA‐like arsenite oxidase gene diversity. The majority of bacterial 16S rRNA gene sequences found in acidic (pH 2.6–3.6) Fe‐oxyhydroxide microbial mats were closely related to Hydrogenobaculum spp. (members of the bacterial order Aquificales), while the predominant sequences from near‐neutral (pH 6.2–8) springs were affiliated with other Aquificales including Sulfurihydrogenibium spp., Thermocrinis spp. and Hydrogenobacter spp., as well as members of the Deinococci, Thermodesulfobacteria and β‐Proteobacteria. Modified primers designed around previously characterized and newly identified aroA‐like genes successfully amplified new lineages of aroA‐like genes associated with members of the Aquificales across all geothermal systems examined. The expression of Aquificales aroA‐like genes was also confirmed in situ, and the resultant cDNA sequences were consistent with aroA genotypes identified in the same environments. The aroA sequences identified in the current study expand the phylogenetic distribution of known Mo‐pterin arsenite oxidase genes, and suggest the importance of three prominent genera of the order Aquificales in arsenite oxidation across geochemically distinct geothermal habitats ranging in pH from 2.6 to 8.
COLONIALISM AND LONG‐RUN GROWTH IN AUSTRALIA: AN EXAMINATION OF INSTITUTIONAL CHANGE IN VICTORIA'S WATER SECTOR DURING THE NINETEENTH CENTURY
Authors: Harris Edwyna
Published: October 2008

Institutional change in water rights in the nineteenth century Australian colony of Victoria raised institutional efficiency, which contributed to long‐run economic growth. High‐quality human capital and the extension of voting rights (franchise) were crucial for efficient institutional change in the water sector. Quality human capital (literacy) appeared to increase the rural population's awareness of the economic impact of the existing structure of water rights that may have constrained growth in the agricultural sector and reduced investment incentives. Extension of the franchise allowed the rural population to exert political pressure for enactment of change in water rights, which resulted in efficiency‐enhancing policies and efficient institutions. The findings show these two factors were more important than Victoria's British colonial heritage in determining whether growth‐enhancing institutional change took place.
THE ECONOMIC CONSEQUENCES OF HARVESTER
Authors: Isaac Joe
Published: October 2008

A century has elapsed since the ‘New Protection’ policy of the newly established Commonwealth government of Australia gave birth to the ‘basic wage’ principle following the ‘Harvester’ judgement. This paper re‐examines, with special reference to economic considerations – unemployment, the tariff, and the wage structure – the controversy surrounding the initial formulation of this principle and the evolution of its application under the federal wage fixing tribunals and the legislation under which they operated. It concludes that even the vestigial remains of the concept underlying Harvester have progressively disappeared from Australian wage fixing principles.
Regulation of an Open Access Essential Facility
Authors: GAUTIER AXEL , MITRA MANIPUSHPAK
Published: October 2008

A vertically integrated firm owns an essential input and operates on the downstream market. There is a potential entrant in the downstream market. Both firms use the same essential input. The regulator's objectives are (i) to ensure financing of the essential input and (ii) to generate competition in the downstream market. The regulatory mechanism grants non‐discriminatory access of the essential facility to the entrant provided it pays a two‐part tariff to the incumbent. The optimal mechanism generates inefficient entry. The inefficient entry captures the trade‐off between market efficiency and infrastructure financing resulting from incomplete information and non‐discriminatory access.
Moral Hazard and Background Risk in Competitive Insurance Markets
Authors: LIGON JAMES A. , THISTLE PAUL D.
Published: October 2008

We examine the effect of background risk on competitive insurance markets with moral hazard. If policy‐holders have non‐negative prudence, then background risk does not decrease effort and, when effort increases, expands the set of feasible policies. However, the effect of background risk on equilibrium is indeterminate. We analyse the choice between stock and mutual insurance; mutual insurance is equivalent to a fair policy plus background risk. Our results imply that competitive insurance markets with moral hazard should be dominated by stock insurers.
Spinoza on the Problem of Akrasia
Authors: Marshall Eugene
Published: October 2008

Abstract: Two common ways of explaining akrasia will be presented, one which focuses on strength of desire and the other which focuses on action issuing from practical judgment. Though each is intuitive in a certain way, they both fail as explanations of the most interesting cases of akrasia. Spinoza's own thoughts on bondage and the affects follow, from which a Spinozist explanation of akrasia is constructed. This account is based in Spinoza's mechanistic psychology of cognitive affects. Because Spinoza's account explains action asissuing from modes of mind that are both cognitive and affective, it captures the intuitions that motivate the two traditional views while avoiding the pitfalls that result from their one‐sided approaches. This project will allow us a fuller understanding of Spinozist moral psychology. In addition to this historical value, the Spinozist theory may offer a satisfactory explanation of certain hard cases of akrasia while avoiding the problems be set by other theories. For this reason, the Spinozist account could also be seen as a useful contribution to our philosophical understanding of the phenomenon of akrasia.
Hemicrania Continua: Who Responds to Indomethacin?
Authors: Marmura MJ , Silberstein SD , Gupta M
Published: October 2008

Hemicrania continua (HC) is a primary headache disorder characterized by a continuous, moderate to severe, unilateral headache and defined by its absolute responsiveness to indomethacin. However, some patients with the clinical phenotype of HC do not respond to indomethacin. We reviewed the records of 192 patients with the putative diagnosis of HC and divided them into groups based on their headaches' response to indomethacin. They were compared for age, gender, presence or absence of specific autonomic symptoms, medication overuse, rapidity of headache onset, and whether or not the headaches met criteria for migraine when severe. Forty-three patients had an absolute response and 122 patients did not respond to adequate doses of indomethacin. The two groups did not differ significantly in terms of age, sex, presence of rapid-onset headache, or medication overuse. Autonomic symptoms, based on a questionnaire, did not predict response. Eighteen patients could not complete a trial of indomethacin due to adverse events. Nine patients could not be included in the HC group despite improvement with indomethacin: one patient probably had primary cough headache, another paroxysmal hemicrania; three patients improved but it was uncertain if they were absolutely pain free, and four patients dramatically improved but still had a baseline headache. We found no statistically significant differences between patients who did and did not respond to indomethacin. All patients with continuous, unilateral headache should receive an adequate trial of indomethacin. Most patients with unilateral headache suggestive of HC did not respond to indomethacin.
Representation of People with Intellectual Disabilities in a British Newspaper in 1983 and 2001
Authors: Wilkinson Penny , McGill Peter
Published: October 2008

Background  Media representation of people with intellectual disabilities may contribute to general perceptions held about them and reflect changes in policy and service provision.

Materials and Methods  Articles from The Guardian newspaper in 2001 were analysed and compared to a previous analysis of material published in 1983.

Results  There was much more coverage of people with autism or Down syndrome than expected from their actual frequency in the British population of people with intellectual disabilities. Newspaper reports continued to be about children more often than expected when about autism or Down syndrome, but not when about people with other intellectual disabilities. Medically related representations were less than in the past but juxtaposition with other client groups continued. More ‘people‐first’ terminology was now used except in respect of people with autism. Articles systematically under‐represented complexity and severity of need.

Conclusions  Policy and service changes may have contributed to the decline of medically‐ and child‐related representations within non‐specific intellectual disabilities. The continued over‐representation of children in articles about autism and Down syndrome, and the generally increased reference to people with those syndromes, suggests growing differentiation within the population of people with intellectual disabilities. The focus on people with less severe or complex disabilities echoes criticisms of Valuing People.
Antipsychotic Medication and People with Intellectual Disabilities: Their Knowledge and Experiences
Authors: Crossley Rachel , Withers Paul
Published: October 2008

Background  Antipsychotics are the most frequently prescribed psychotropic medication for people with intellectual disabilities. Many people are prescribed this medication for ‘challenging behaviours’ without having had a formal diagnosis of a psychiatric disorder. Antipsychotics have been reported to have severe side‐effect profiles, which can hamper quality of life.

Materials and Methods  Grounded theory qualitative methodology was employed to organize and analyse data from interviews conducted with eight adults with intellectual disabilities about their experiences of antipsychotic medication.

Results  Respondents had little knowledge about their medication, beyond knowing their regime. Despite participants experiencing side effects, they were accepting of these effects. A ‘model of compliance’ was generated from the analysis.

Conclusions  The prescription and administration of medication is another area where people with intellectual disabilities experience lack of control and disempowerment. ‘Services’ need to do more to include and inform people with intellectual disabilities about their medication.
Identifying Rarer Genetic Variants for Common Complex Diseases: Diseased Versus Neutral Discovery Panels
Authors: Curtin K. , Iles M. M. , Camp N. J.
Published: October 2008

The power of genetic association studies to identify disease susceptibility alleles fundamentally relies on the variants studied. The standard approach is to determine a set of tagging‐SNPs (tSNPs) that capture the majority of genomic variation in regions of interest by exploiting local correlation structures. Typically, tSNPs are selected from neutral discovery panels ‐ collections of individuals comprehensively genotyped across a region. We investigated the implications of discovery panel design on tSNP performance in association studies using realistically‐simulated sequence data. We found that discovery panels of 24 sequenced ‘neutral’ individuals (similar to NIEHS or HapMap ENCODE data) were sufficient to select well‐powered tSNPs to identify common susceptibility alleles. For less common alleles (0.01–0.05 frequency) we found neutral panels of this size inadequate, particularly if low‐frequency variants were removed prior to tSNP selection; superior tSNPs were found using panels of diseased individuals. Only large neutral panels (200 individuals) matched diseased panel performance in selecting well‐powered tSNPs to detect both common and rarer alleles. The 1000 Genomes Project initiative may provide larger neutral panels necessary to identify rarer susceptibility alleles in association studies. In the interim, our results suggest investigators can boost power to detect such alleles by sequencing diseased individuals for tSNP selection.
Evolutionary history of the critically endangered Cozumel dwarf carnivores inferred from mitochondrial DNA analyses
Authors: McFadden K. W. , Gompper M. E. , Valenzuela D. G. , Morales J. C.
Published: October 2008

The pygmy raccoon Procyon pygmaeus and dwarf coati Nasua nelsoni, both endemic to Cozumel Island, Mexico, are two of the most endangered carnivores in the world, and their persistence requires active management. However, the taxonomic status of these populations remains unclear. Therefore we investigated mitochondrial DNA variation using the control region to examine the genetic uniqueness and evolutionary history of these taxa. Using strict phylogenetic criteria, species‐level uniqueness of the Cozumel taxa was difficult to discern based solely on haplotype groupings and identification of unique alleles. However, population genetic approaches indicate significant population differentiation between Cozumel and mainland populations and we suggest that these taxa should be treated as distinct management units from their mainland conspecifics. Coalescent analysis indicated that the pygmy raccoon diverged from the mainland about 3050–200 111 years before present (ybp) and the Cozumel coati 1263–82 896 ybp; dates that can be further constrained by incorporating known‐age subfossil specimens from Cozumel as well as the geological history of the island. Thus, although it is likely that the island taxa colonized Cozumel before the Mayan peoples populated the island, we are unable to definitively reject the hypothesis that colonization by these taxa was not human facilitated.
Chordate phylogeny and evolution: a not so simple three‐taxon problem
Authors: Stach T.
Published: October 2008

Traditional concepts of chordate phylogeny have recently been in turmoil: in a large‐scale molecular study, the traditional hypothesis that cephalochordates are sister taxon to craniates was replaced by the hypothesis of a sister group relationship between tunicates and craniates. It was claimed that the morphological evidence that supported traditional phylogeny was weak and that morphological characters at least equally strong could be mustered in support of the ‘new phylogeny.’ In the present review, it is shown that the uncritical use of published codings of morphological characters in recent phylogenetic analyses is responsible for this perception. To ameliorate this situation, the main focus of the present publication is a review of the morphological evidence that has been deemed relevant in chordate phylogeny. Characters are presented in enough detail to allow readers to make self‐reliant informed decisions on character coding. I then analyze these characters cladistically, and it is demonstrated that support of the traditional hypothesis is substantial. I briefly evaluate molecular systematic studies and criticize ‘evo‐devo’ studies for lack of cladistic rigor in the evolutionary interpretations of their data by (1) failing to formally code their characters (2) failing to subject their data to the congruence test with other characters, the crucial test in phylogenetic analyses. Finally, a short and by necessity eclectic discussion of suggested evolutionary scenarios is presented.
Boys will be boys: social affinity among males drives social segregation in western grey kangaroos
Authors: MacFarlane A. M. , Coulson G.
Published: October 2008

In many sexually dimorphic and polygynous species, individuals exhibit social segregation by grouping with others of their own sex. Several proximate mechanisms have been proposed to explain social segregation: female avoidance of males, male avoidance of females, avoidance of harassment, male social affinity, female social affinity and activity budget asynchrony. Some of these have been tested in ungulate species, but few previous studies have been able to rigorously test, or distinguish between, these mechanisms because they have failed to examine the fission/fusion dynamics of groups. We tested these proximate mechanisms simultaneously in western grey kangaroos Macropus fuliginosus, by examining whether females, small males or large males instigated segregation by leaving mixed‐sex groups or joining individuals of their own sex or size class. Females, small males and large males left mixed‐sex groups as if leaving were independent of sex–size class. In contrast, large males joined male‐only groups more frequently than expected. These results suggest that the need for males to maintain contact with other males can contribute to the cohesion of male‐only groups and promote segregation. As male–male competition occurs in many polygynous species that sexually segregate, a comparable mechanism might be operating in other taxa, and should be examined further.
Pregnancy outcomes following hospitalisation for a fall in Washington State from 1987 to 2004*
Authors: Schiff MA
Published: October 2008

Objective  To evaluate the risk of adverse maternal and perinatal outcomes among pregnant women hospitalised following falls.

Design  A population‐based retrospective cohort study.

Setting  Washington State, USA.

Population  Pregnant women with a fetal death or live birth certificate linked to the hospitalisation discharge data from 1987 to 2004.

Methods  Pregnant women who experienced a fall (n = 693) were identified by the presence of an International Classification of Disease—9th Edition external causation code of E880 through E888 and were compared with a randomly chosen group of pregnant women (n = 2079) not experiencing a fall hospitalisation during pregnancy. Poisson regression analysis was used to estimate adjusted relative risks (RR) and 95% CI for associations between falls and pregnancy outcomes.

Main outcome measures  Preterm labour and delivery, placental abruption, fetal distress, and fetal hypoxia.

Results  This study found an incidence rate of 48.9 pregnant fall hospitalisations per 100 000 deliveries. The majority of the fall hospitalisations occurred in the third trimester (79.3%), with 11.3% in the second trimester and 9.4% in the first trimester. The majority of injuries due to falls were fractures (47.4%), especially of the lower extremity, followed by contusions (18.0%) and sprains (17.3%). Falls were associated with an increased risk of preterm labour (RR 4.4, 95% CI 3.4–5.7), placental abruption (RR 8.0, 95% CI 4.3–15.0), fetal distress (RR 2.1, 95% CI 1.6–2.8), and fetal hypoxia (RR 2.9, 95% CI 1.3–6.5).

Conclusion  In light of the increased risk of adverse maternal and perinatal outcomes associated with major falls resulting in hospitalisation, careful maternal and fetal monitoring following a major fall is warranted.
Does miscarriage in an initial pregnancy lead to adverse obstetric and perinatal outcomes in the next continuing pregnancy?
Authors: Bhattacharya S , Townend J , Shetty A , Campbell D , Bhattacharya S
Published: October 2008

Objective  To explore pregnancy outcomes in women following an initial miscarriage.

Design  Retrospective Cohort Study.

Setting  Aberdeen Maternity Hospital, Aberdeen, Scotland.

Population  All women living in the Grampian region of Scotland with a pregnancy recorded in the Aberdeen Maternity and Neonatal Databank between 1986 and 2000.

Main outcome measures  (A) Maternal outcomes: Pre‐eclampsia, antepartum haemorrhage, threatened miscarriage, malpresenation, induced labour, instrumental delivery, Caesarean delivery, postpartum haemorrhage and manual removal of placenta. (B) Perinatal outcomes: preterm delivery, low birth weight, stillbirth, neonatal death, Apgar score at 5 minutes.

Methods  Retrospective cohort study comparing women with a first pregnancy miscarriage with (a) women with one previous successful pregnancy and (b) primigravid women. Data were extracted on perinatal outcomes in all women from the Aberdeen Maternity and Neonatal Databank between 1986 and 2000.

Results  We identified 1561 women who had a first miscarriage (1404 in the first trimester and 157 in the second trimester), 10 549 who had had a previous live birth (group A) and 21 118 primigravidae (group B). The miscarriage group faced a higher risk of pre‐eclampsia (adj OR 3.3, 99% CI 2.6–4.6), threatened miscarriage (adj OR 1.7, 99% CI 1.5–2.0), induced labour (adj OR 2.2, 99% CI 1.9–2.5), instrumental delivery (adj OR 5.9, 99% CI 5.0–6.9), preterm delivery (adj OR 2.1, 99% CI 1.6–2.8) and low birthweight (adj OR 1.6, 99% CI 1.3–2.1) than group A. They were more likely to have threatened miscarriage (adj OR 1.5, 99% CI 1.4–1.7), induced labour (adj OR 1.3, 99% CI 1.2–1.5), postpartum haemorrhage (adj OR 1.4, 99% CI 1.2–1.6) and preterm delivery (adj OR 1.5, 99% CI 1.2–1.8) than group B.

Conclusion  An initial miscarriage is associated with a higher risk of obstetric complications.
Non‐invasive quantification of brain glycogen absolute concentration
Authors: Morgenthaler Florence D. , Van Heeswijk Ruud B. , Xin Lijing , Laus Sabrina , Frenkel Hanne , Lei Hongxia , Gruetter Rolf
Published: October 2008

The only currently available method to measure brain glycogen in vivo is 13C NMR spectroscopy. Incorporation of 13C‐labeled glucose (Glc) is necessary to allow glycogen measurement, but might be affected by turnover changes. Our aim was to measure glycogen absolute concentration in the rat brain by eliminating label turnover as variable. The approach is based on establishing an increased, constant 13C isotopic enrichment (IE). 13C‐Glc infusion is then performed at the IE of brain glycogen. As glycogen IE cannot be assessed in vivo, we validated that it can be inferred from that of N‐acetyl‐aspartate IE in vivo: After [1‐13C]‐Glc ingestion, glycogen IE was 2.2 ± 0.1 fold that of N‐acetyl‐aspartate (n = 11, R2 = 0.77). After subsequent Glc infusion, glycogen IE equaled brain Glc IE (n = 6, paired t‐test, p = 0.37), implying isotopic steady‐state achievement and complete turnover of the glycogen molecule. Glycogen concentration measured in vivo by 13C NMR (mean ± SD: 5.8 ± 0.7 μmol/g) was in excellent agreement with that in vitro (6.4 ± 0.6 μmol/g, n = 5). When insulin was administered, the stability of glycogen concentration was analogous to previous biochemical measurements implying that glycogen turnover is activated by insulin. We conclude that the entire glycogen molecule is turned over and that insulin activates glycogen turnover.
Mandatory IFRS Reporting around the World: Early Evidence on the Economic Consequences
Authors: DASKE HOLGER , HAIL LUZI , LEUZ CHRISTIAN , VERDI RODRIGO
Published: October 2008

This paper examines the economic consequences of mandatory International Financial Reporting Standards (IFRS) reporting around the world. We analyze the effects on market liquidity, cost of capital, and Tobin's q in 26 countries using a large sample of firms that are mandated to adopt IFRS. We find that, on average, market liquidity increases around the time of the introduction of IFRS. We also document a decrease in firms' cost of capital and an increase in equity valuations, but only if we account for the possibility that the effects occur prior to the official adoption date. Partitioning our sample, we find that the capital‐market benefits occur only in countries where firms have incentives to be transparent and where legal enforcement is strong, underscoring the central importance of firms' reporting incentives and countries' enforcement regimes for the quality of financial reporting. Comparing mandatory and voluntary adopters, we find that the capital market effects are most pronounced for firms that voluntarily switch to IFRS, both in the year when they switch and again later, when IFRS become mandatory. While the former result is likely due to self‐selection, the latter result cautions us to attribute the capital‐market effects for mandatory adopters solely or even primarily to the IFRS mandate. Many adopting countries make concurrent efforts to improve enforcement and governance regimes, which likely play into our findings. Consistent with this interpretation, the estimated liquidity improvements are smaller in magnitude when we analyze them on a monthly basis, which is more likely to isolate IFRS reporting effects.
On the Value Relevance of Asymmetric Financial Reporting Policies
Authors: SUIJS JEROEN
Published: October 2008

This paper considers an overlapping generations model where investors trade in a firm's stock. Investment risk is partly determined by the volatility of the stock price at which current investors can sell their shares to the next generation of investors. It is shown that asymmetric reporting of good and bad news is value relevant as it affects the allocation of risk among future generations of shareholders.
Cerebral Venous Thrombosis in Spontaneous Intracranial Hypotension
Authors: Schievink Wouter I. , Maya Menahem Marcel
Published: October 2008

Background and Objective.— The occurrence of cerebral venous thrombosis has been reported among patients with spontaneous intracranial hypotension, but a causal relationship has not been clearly established. We reviewed our experience with spontaneous intracranial hypotension and cerebral venous thrombosis and we reviewed the relevant literature to evaluate the relationship between these 2 entities.

Methods.— We reviewed the medical records and imaging studies of a consecutive group of patients with spontaneous intracranial hypotension evaluated at a tertiary care center between 1/1/2001 and 12/31/2007. The main search strategy was a systemic review of journal articles in MEDLINE (1966 to January 2008).

Results.— Among 141 patients with spontaneous intracranial hypotension, 3 (2.1%) were also diagnosed with cerebral venous thrombosis. Among these 3 patients and the 17 reported in the literature there were 11 men and 9 women with a mean age of 39.5 years. Radiographic or clinical evidence for spontaneous intracranial hypotension preceding cerebral venous thrombosis was found in most patients, while there was no evidence for cerebral venous thrombosis preceding spontaneous intracranial hypotension in any patient. Eight (40%) of the 20 patients were found to have a change in their headache pattern believed to be due to the development of cerebral venous thrombosis. Complications of cerebral venous thrombosis, eg, cerebral venous infarction, occurred in 8 patients (40%).

Conclusions.— Spontaneous intracranial hypotension is a risk factor for cerebral venous thrombosis, but cerebral venous thrombosis is found in only about 2% of patients with spontaneous intracranial hypotension. A change in headache pattern is not a reliable predictor of the development of cerebral venous thrombosis in patients with spontaneous intracranial hypotension.
Nerve Stimulator‐Guided Occipital Nerve Blockade for Postdural Puncture Headache
Authors: Naja Zoher , Al‐Tannir Mohamad , El‐Rajab Mariam , Ziade Fouad , Baraka Anis
Published: October 2008

Postdural puncture headache (PDPH) is one of the most common complications of spinal anesthesia, where adequate hydration with bed rest in the horizontal position is the initial recommendation. Epidural blood patch is to date the most effective treatment, but it is an invasive procedure that may result in serious complications. The aim of the current study was to conduct a prospective, randomized, single‐blinded comparison between bilateral occipital blockade and conventional expectant therapy in adults suffering from PDPH. A primary hypothesis was that occipital blockade would result in better pain management and quicker return to normal activity. Fifty adult patients diagnosed with PDPH were randomly divided into two equal groups of 25 each. All patients in the block group received greater and lesser occipital nerve blocks, whereas the control group received adequate hydration, complete bed rest, and analgesics. Forty‐seven patients entered into the final analysis as three patients withdrew from study. Complete pain relief was achieved in 68.4% of block patients after 1 to 2 blocks, with 31.6% ultimately receiving up to 4 blocks. Visual analog scales were significantly lower in the block group (P < 0.01), and the block group consumed significantly less analgesics in the follow‐up period (P < 0.05) compared with control group. Block patients had significantly shorter hospital stays and sick leave periods (P < 0.001). The studied method is superior to expectant conservative therapy in the treatment of patients suffering from PDPH.
A Multinomial‐Dirichlet Model for Analysis of Competing Hypotheses
Authors: Duncan Kristin A. , Wilson Jonathan L.
Published: October 2008

Analysis of competing hypothesis, a method for evaluating explanations of observed evidence, is used in numerous fields, including counterterrorism, psychology, and intelligence analysis. We propose a Bayesian extension of the methodology, posing the problem in terms of a multinomial‐Dirichlet hierarchical model. The yet‐to‐be observed true hypothesis is regarded as a multinomial random variable and the evaluation of the evidence is treated as a structured elicitation of a prior distribution on the probabilities of the hypotheses. This model provides the user with measures of uncertainty for the probabilities of the hypotheses. We discuss inference, such as point and interval estimates of hypothesis probabilities, ratios of hypothesis probabilities, and Bayes factors. A simple example involving the stadium relocation of the San Diego Chargers is used to illustrate the method. We also present several extensions of the model that enable it to handle special types of evidence, including evidence that is irrelevant to one or more hypotheses, evidence against hypotheses, and evidence that is subject to deception.
Combined Assessment of Myocardial Perfusion and Diastolic Function Enhances Risk Stratification in Patients with Anterior Wall Myocardial Infarction
Authors: Khumri Taiyeb M. , Walker Brandy L. , Magalski Anthony , Morris Becky A. , Coggins Tina R. , Kusnetzky Lisa L. , House John A. , Main Michael L.
Published: October 2008

Objective: Evaluate the utility of a combined risk stratification scheme including diastolic dysfunction and “no‐reflow,” to identify high‐risk patients following acute myocardial infarction (AMI). Background: Recent studies have demonstrated that the “no‐reflow” phenomenon (defined by myocardial contrast echocardiography) and severe diastolic dysfunction (identified by Doppler echocardiography) identify patients at high risk for mortality following AMI. Methods: We evaluated 111 patients with recent anterior acute myocardial infarction from July 2000 to June 2004. Diastolic function and myocardial perfusion was evaluated by echocardiography. Patients were placed into 1 of 3 groups based on diastolic function and myocardial perfusion: Group 1 (normal perfusion and normal diastolic function), Group 2 (abnormal perfusion or abnormal diastolic function), and Group 3 (abnormal perfusion and abnormal diastolic function). We compared the long term all‐cause mortality within these groups. Results: Patients in each group were similar with respect to myocardial infarction size as defined by biomarkers, extent and severity of coronary artery disease, and medical and interventional therapy. Mortality was much higher in Group 3 (26.9%) compared to Group 1 (0%) and Group 2 (15.2%) (p = 0.048). Conclusion: Combined assessment of diastolic function and myocardial perfusion enhances risk stratification post myocardial infarction.
In Vitro Two‐Dimensional Echocardiographic Imaging of a Stented Porcine Bioprosthetic Valve: The Bent Strut Artifact
Authors: Bach David S.
Published: October 2008

Background: Echocardiographic imaging of a stented valve bioprosthesis can reveal apparent inward deflection of one or more struts. It could be assumed that this finding is related to actual strut distortion as opposed to an artifact of off‐axis imaging. Objective: To determine whether normal (nondistorted) bioprosthetic struts can appear by artifact to be bent inward on two‐dimensional echocardiographic imaging. Methods: A production‐quality porcine bioprosthetic aortic valve was imaged in vitro using standard two‐dimensional echocardiographic techniques. Apparent strut distortion on echocardiographic imaging was investigated relative to prosthesis orientation to the transducer. Results: The appearance of inward strut distortion was produced when two of three struts were simultaneously imaged, including imaging in an off‐axis long axis orientation and from above or below the prosthesis. Conclusion: Apparent inward distortion of bioprosthetic struts can be simulated in vitro using a normal, nondistorted valve, and is common if two struts are simultaneously imaged. A finding of inward distortion of strut tips on in vivo imaging should be used with caution, since the finding may not be representative of actual strut anatomy.
Death Caused by Splenic Artery Aneurysm Rupture during Dobutamine–Atropine Stress Echocardiography: Case Report and Literature Review
Authors: Klaas James P. , Diller Christina L. , Harmon James V. , Skarda David E.
Published: October 2008

A 55‐year‐old man developed hypertension and acute epigastric pain during dobutamine–atropine stress echocardiography (DASE). Evaluation—including a helical computed tomography (CT) scan of the abdomen and pelvis, as well as surgical exploration—revealed a ruptured splenic artery aneurysm. The patient died, despite multiple surgical interventions and a massive blood product transfusion. Impressively, no deaths from DASE have been previously reported. Additionally, no adverse sequelae during DASE have been reported in patients with an unruptured abdominal aortic aneurysm ≥4 cm in diameter or with an unruptured intracranial aneurysm. We report the first case, to our knowledge, of death caused by splenic artery aneurysm rupture during DASE. Splenic artery aneurysm rupture during DASE, though rare, can lead to death.
Two‐Stage Sintering of Nanosize Pure Zirconia
Authors: Tartaj Jesus , Tartaj Pedro
Published: October 2008

We report a two‐stage pressureless heating schedule for the preparation of crack‐free and dense pure zirconia (ZrO2) monoliths with grain sizes close to the nanoscale. The use of nanosize ZrO2 powders prepared by a modified microemulsion synthetic route was essential for the success of this two‐stage sintering approach. Green compacts made from these powders present a narrow pore size distribution and a low‐agglomeration state. Temperatures for the two‐stage heating schedule were selected after analyzing the thermal evolution of green compacts by shrinkage, density, and high‐temperature X‐ray diffraction studies. During the first stage of the thermal processing, the green body was heated at 960°C–10 h to obtain a compact with a high density and near‐nanosize grains. In the second stage, the compact was heated at 1150°C–2 h to obtain fully dense compacts. Microcracks were prevented because 1150°C is below the reversible but disruptive monoclinic–tetragonal phase transformation.
Sintering Diamond/Cemented Carbides by the Pulse Plasma Sintering Method
Authors: Michalski Andrzej , Rosiński Marcin
Published: October 2008

Under the conditions of thermodynamic instability, we produced dense sintered composites built of diamond particles (30 vol%) and a cemented carbide matrix. The composites were consolidated by high‐current electric pulses at a temperature of about 1100°C and load of 75 MPa for 5 min. The diamond particles are strongly bound with the cemented carbide matrix, by a transition layer composed of a solid solution of carbon and tungsten in cobalt. No graphite precipitates were found in the sintered composites, as examined by microstructure observations, examinations of the phase composition, and an analysis of the Raman scattering spectra. The hardness of the diamond/cemented carbide was 23 GPa.
The Beauty Premium: Physical Attractiveness and Gender in Dictator Games
Authors: Rosenblat Tanya S.
Published: October 2008

Are beautiful people better negotiators? In this article, I present evidence from a simple bargaining game in which players listened to prerecorded speeches and viewed the pictures of other players. I found that physically attractive players received a greater share of the surplus when their partners could both listen to their speeches and view their pictures. This effect was strongest when the listening partner was female. These results suggest new directions for experimental and empirical research on the role of nonresumé characteristics on labor market outcomes, and also has implications for those practitioners involved in negotiations characterized by extreme power imbalances between the parties.
To Flirt or Not to Flirt? Sexual Power at the Bargaining Table
Authors: Kray Laura J. , Locke Connson C.
Published: October 2008

We begin by exploring the lay belief that women can use flirtation to their advantage in professional contexts and contrast it with trained negotiators’ negative views on flirtation. We then examine the impact of flirtation on negotiators’ impression formation. We explore whether a flirtatious style aids women in the trade‐off they often face between perceived likability and perceived competence. We discover both an upside and a downside to flirting at the bargaining table. Although flirtation appears to be positively related to women's likability, negotiators who flirted were judged to be less authentic than those who refrained from exercising their sexual power.