bluuebunny/crossref_metadata_2025 huggingface dataset:
Periodic solutions and stability for a weakly damped nonlinear Mathieu equation
Authors: El-Bassiouny A F , Abdel-Khalik A
Published: December 2009

Periodic solutions are investigated for a weakly damped nonlinear Mathieu equation. The multiple scales perturbation technique is used to determine a third-order solution for a nonlinear Mathieu equation. We derive a first reduced differential amplitude–phase system having periodic components. These equations are used to determine the fixed points. The stability of stationary solutions of this reduced system is analyzed. Numerical solutions are presented, which illustrate the behavior of the steady-state response amplitude as a function of the detuning parameter. Stability analysis is carried out for each case. The effects of these (quadratic and cubic ) nonlinearities on these oscillations are specifically investigated. With this study, it has been verified that the qualitative effects of these nonlinearities are different.
Cross-field dust acoustic instability in a dusty negative ion plasma
Authors: Rosenberg M
Published: December 2009

A cross-field dust acoustic instability in a dusty negative ion plasma in a magnetic field is studied using kinetic theory. The instability is driven by the E×B drifts of the ions. It is assumed that the negative ions are much heavier than the positive ions, and that the dust is negatively charged. The case where the positive ions and electrons are magnetized, the negative ions are marginally unmagnetized, and the dust is unmagnetized is considered. The focus is on a situation where Doppler resonances near harmonics of the positive ion gyrofrequency can affect the spectrum of unstable dust acoustic waves. Application to possible laboratory experimental parameters is discussed.
Role of trapped electrons on the propagation of localized dust ion-acoustic waves
Authors: Alinejad H
Published: December 2009

The nonlinear propagation of arbitrary amplitude of dust ion-acoustic (DIA) waves in an unmagnetized dusty plasma composed of a cold ion fluid, stationary dust grains and hot electrons obeying a trapped distribution, is investigated. The trapped particles are included in this model as a result of the nonlinear resonant interaction of the localized electrostatic wave potential with electrons during its evolution. The properties of large amplitude solitary waves are studied by deriving an energy integral equation involving the Sagdeev potential, whereas those of small but finite amplitude DIA solitary waves are investigated by means of the reductive perturbation method. The new parametric regimes for the existence of solitary structures are found, and the effects of trapped electrons along with static dust particles on these profiles are discussed.
GWAF: an R package for genome-wide association analyses with family data
Authors: Chen Ming-Huei , Yang Qiong
Published: December 2009

Summary: GWAF, Genome-Wide Association analyses with Family, is an R package designed for GWAF. It implements association tests between a batch of genotyped or imputed single nucleotide polymorphisms (SNPs) and a binary or continuous trait with user specified genetic model, and generates informative results from the analyses. In addition, GWAF provides functions to visualize results. We evaluated GWAF using a simulated continuous trait and a binary trait dichotomized from the simulated continuous trait with real genotype data from the Framingham Heart Study's SNP Health Association Resource project.

Availability:  http://cran.r-project.org/web/packages/GWAF/

Contact:  qyang@bu.edu

Supplementary information:  Supplementary data are available at Bioinformatics online.
High-throughput sequencing of retrotransposon integration provides a saturated profile of target activity in Schizosaccharomyces pombe
Authors: Guo Yabin , Levin Henry L.
Published: December 2009

The biological impact of transposons on the physiology of the host depends greatly on the frequency and position of integration. Previous studies of Tf1, a long terminal repeat retrotransposon in Schizosaccharomyces pombe, showed that integration occurs at the promoters of RNA polymerase II (Pol II) transcribed genes. To determine whether specific promoters are preferred targets of integration, we sequenced large numbers of insertions using high-throughput pyrosequencing. In four independent experiments we identified a total of 73,125 independent integration events. These data provided strong support for the conclusion that Pol II promoters are the targets of Tf1 integration. The size and number of the integration experiments resulted in reproducible measures of integration for each intergenic region and ORF in the S. pombe genome. The reproducibility of the integration activity from experiment to experiment demonstrates that we have saturated the full set of insertion sites that are actively targeted by Tf1. We found Tf1 integration was highly biased in favor of a specific set of Pol II promoters. The overwhelming majority (76%) of the insertions were distributed in intergenic sequences that contained 31% of the promoters of S. pombe. Interestingly, there was no correlation between the amount of integration at these promoters and their level of transcription. Instead, we found Tf1 had a strong preference for promoters that are induced by conditions of stress. This targeting of stress response genes coupled with the ability of Tf1 to regulate the expression of adjacent genes suggests Tf1 may improve the survival of S. pombe when cells are exposed to environmental stress.
ArabidopsisTic62 and Ferredoxin-NADP(H) Oxidoreductase Form Light-Regulated Complexes That Are Integrated into the Chloroplast Redox Poise
Authors: Benz J.P. , Stengel A. , Lintala M. , Lee Y.-H. , Weber A. , Philippar K. , Gügel I.L. , Kaieda S. , Ikegami T. , Mulo P. , Soll J. , Bölter B.
Published: December 2009

Translocation of nuclear-encoded preproteins across the inner envelope of chloroplasts is catalyzed by the Tic translocon, consisting of Tic110, Tic40, Tic62, Tic55, Tic32, Tic20, and Tic22. Tic62 was proposed to act as a redox sensor of the complex because of its redox-dependent shuttling between envelope and stroma and its specific interaction with the photosynthetic protein ferredoxin-NADP(H) oxidoreductase (FNR). However, the nature of this close relationship so far remained enigmatic. A putative additional localization of Tic62 at the thylakoids mandated further studies examining how this feature might be involved in the respective redox sensing pathway and the interaction with its partner protein. Therefore, both the association with FNR and the physiological role of the third, thylakoid-bound pool of Tic62 were investigated in detail. Coexpression analysis indicates that Tic62 has similar expression patterns as genes involved in photosynthetic functions and protein turnover. At the thylakoids, Tic62 and FNR form high molecular weight complexes that are not involved in photosynthetic electron transfer but are dynamically regulated by light signals and the stromal pH. Structural analyses reveal that Tic62 binds to FNR in a novel binding mode for flavoproteins, with a major contribution from hydrophobic interactions. Moreover, in absence of Tic62, membrane binding and stability of FNR are drastically reduced. We conclude that Tic62 represents a major FNR interaction partner not only at the envelope and in the stroma, but also at the thylakoids of Arabidopsis thaliana and perhaps all flowering plants. Association with Tic62 stabilizes FNR and is involved in its dynamic and light-dependent membrane tethering.
Two Types of Meiotic Crossovers Coexist in Maize
Authors: Falque Matthieu , Anderson Lorinda K. , Stack Stephen M. , Gauthier Franck , Martin Olivier C.
Published: December 2009

We apply modeling approaches to investigate the distribution of late recombination nodules in maize (Zea mays). Such nodules indicate crossover positions along the synaptonemal complex. High-quality nodule data were analyzed using two different interference models: the “statistical” gamma model and the “mechanical” beam film model. For each chromosome, we exclude at a 98% significance level the hypothesis that a single pathway underlies the formation of all crossovers, pointing to the coexistence of two types of crossing-over in maize, as was previously demonstrated in other organisms. We estimate the proportion of crossovers coming from the noninterfering pathway to range from 6 to 23% depending on the chromosome, with a cell average of ∼15%. The mean number of noninterfering crossovers per chromosome is significantly correlated with the length of the synaptonemal complex. We also quantify the intensity of interference. Finally, we develop inference tools that allow one to tackle, without much loss of power, complex crossover interference models such as the beam film. The lack of a likelihood function in such models had prevented their use for parameter estimation. This advance will allow more realistic mechanisms of crossover formation to be modeled in the future.
PIN Auxin Efflux Carrier Polarity Is Regulated by PINOID Kinase-Mediated Recruitment into GNOM-Independent Trafficking inArabidopsis
Authors: Kleine-Vehn Jürgen , Huang Fang , Naramoto Satoshi , Zhang Jing , Michniewicz Marta , Offringa Remko , Friml Jiří
Published: December 2009

The phytohormone auxin plays a major role in embryonic and postembryonic plant development. The temporal and spatial distribution of auxin largely depends on the subcellular polar localization of members of the PIN-FORMED (PIN) auxin efflux carrier family. The Ser/Thr protein kinase PINOID (PID) catalyzes PIN phosphorylation and crucially contributes to the regulation of apical-basal PIN polarity. The GTP exchange factor on ADP-ribosylation factors (ARF-GEF), GNOM preferentially mediates PIN recycling at the basal side of the cell. Interference with GNOM activity leads to dynamic PIN transcytosis between different sides of the cell. Our genetic, pharmacological, and cell biological approaches illustrate that PID and GNOM influence PIN polarity and plant development in an antagonistic manner and that the PID-dependent PIN phosphorylation results in GNOM-independent polar PIN targeting. The data suggest that PID and the protein phosphatase 2A not only regulate the static PIN polarity, but also act antagonistically on the rate of GNOM-dependent polar PIN transcytosis. We propose a model that includes PID-dependent PIN phosphorylation at the plasma membrane and the subsequent sorting of PIN proteins to a GNOM-independent pathway for polarity alterations during developmental processes, such as lateral root formation and leaf vasculature development.
Cell Type–Specific Chromatin Decondensation of a Metabolic Gene Cluster in Oats
Authors: Wegel Eva , Koumproglou Rachil , Shaw Peter , Osbourn Anne
Published: December 2009

Transcription-related chromatin decondensation has been studied in mammals for clusters of structurally and/or functionally related genes that are coordinately regulated (e.g., the homeobox locus in mice and the major histocompatability complex locus in humans). Plant genes have generally been considered to be randomly distributed throughout the genome, although several examples of metabolic gene clusters for synthesis of plant defense compounds have recently been discovered. Clustering provides for genetic linkage of genes that together confer a selective advantage and may also facilitate coordinate regulation of gene expression by enabling localized changes in chromatin structure. Here, we use cytological methods to investigate components of a metabolic gene cluster for synthesis of developmentally regulated defense compounds (avenacins) in diploid oat (Avena strigosa). Our experiments reveal that expression of the avenacin gene cluster is associated with cell type–specific chromatin decondensation, providing new insights into regulation of gene clusters in plants. Importantly, chromatin decondensation could be visualized not only at the large-scale level but down to the single gene level. We further show that the avenacin and sterol pathways are likely to be inversely regulated at the level of transcription.
Movement and Remodeling of the Endoplasmic Reticulum in Nondividing Cells of Tobacco Leaves
Authors: Sparkes I. , Runions J. , Hawes C. , Griffing L.
Published: December 2009

Using a novel analytical tool, this study investigates the relative roles of actin, microtubules, myosin, and Golgi bodies on form and movement of the endoplasmic reticulum (ER) in tobacco (Nicotiana tabacum) leaf epidermal cells. Expression of a subset of truncated class XI myosins, which interfere with the activity of native class XI myosins, and drug-induced actin depolymerization produce a more persistent network of ER tubules and larger persistent cisternae. The treatments differentially affect two persistent size classes of cortical ER cisternae, those >0.3 μm2 and those smaller, called punctae. The punctae are not Golgi, and ER remodeling occurs in the absence of Golgi bodies. The treatments diminish the mobile fraction of ER membrane proteins but not the diffusive flow of mobile membrane proteins. The results support a model whereby ER network remodeling is coupled to the directionality but not the magnitude of membrane surface flow, and the punctae are network nodes that act as foci of actin polymerization, regulating network remodeling through exploratory tubule growth and myosin-mediated shrinkage.
The application of mass‐spectrometry‐based protein biomarker discovery to theragnostics
Authors: Street Jonathan M. , Dear James W.
Published: December 2009

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

• The techniques used in protein biomarker discovery have been described in specialist journals.

WHAT THIS STUDY ADDS

• This review aims to provide a useful toolkit for the researcher (especially the less experienced) that suggests answers to common questions and demystifies some of the technology.

Over the last decade rapid developments in mass spectrometry have allowed the identification of multiple proteins in complex biological samples. This proteomic approach has been applied to biomarker discovery in the context of clinical pharmacology (the combination of biomarker and drug now being termed ‘theragnostics’). In this review we provide a roadmap for early protein biomarker discovery studies, focusing on some key questions that regularly confront researchers.
Pharmacokinetic and pharmacodynamic analysis of enteric‐coated mycophenolate sodium: limited sampling strategies and clinical outcome in renal transplant patients
Authors: Sommerer Claudia , Müller‐Krebs Sandra , Schaier Matthias , Glander Petra , Budde Klemens , Schwenger Vedat , Mikus Gerd , Zeier Martin
Published: December 2009

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

• Therapeutic drug monitoring of mycophenolate mofetil is a promising tool for reducing acute rejection episodes after renal transplantation.

• Limited sampling algorithms of mycophenolic acid in mycophenolate mofetil‐treated renal transplant patients have been established.

• Recently published study results indicate that the intensity of early drug exposure might determine the risk of acute rejection episodes.

WHAT THIS STUDY ADDS

• This study provides pharmacokinetic and pharmacodynamic data of mycophenolic acid in enteric‐coated mycophenolate sodium‐treated renal transplant patients.

• Limited sampling algorithms are evaluated and a practical sampling strategy with five sampling time points within the first 4 h after oral drug intake is provided in renal transplant patients with combined immunosuppression consisting of enteric‐coated mycophenolate sodium and ciclosporin A.

• The association between pharmacokinetic and pharmacodynamic parameters and the risk of adverse events are evaluated.

• Both pharmacokinetic and pharmacodynamic parameters contribute to optimized individual immunosuppression.

AIMS Pharmacokinetic (PK) and pharmacodynamic (PD) monitoring strategies and clinical outcome were evaluated in enteric‐coated mycophenolate sodium (EC‐MPS)‐treated renal allograft recipients.

METHODS PK [mycophenolic acid (MPA)] and PD [inosine monophosphate dehydrogenase (IMPDH) activity] data were analysed in 66 EC‐MPS and ciclosporin A (CsA)‐treated renal allograft recipients. Adverse events were considered in a follow‐up period of 12 weeks.

RESULTS Analyses confirmed a limited sampling strategy (LSS) consisting of PK and PD data at predose, 1, 2, 3 and 4 h after oral intake as an appropriate sampling method (MPA r2= 0.812; IMPDH r2= 0.833). MPA AUC0–12 of patients with early biopsy‐proven acute rejection was significantly lower compared with patients without a rejection (median MPA AUC0–12 28 µg*h ml−1 (7–45) vs. 40 µg*h ml−1 (16–130), P < 0.01), MPA AUC0–12 of patients with recurrent infections was significantly higher compared with patients without infections (median MPA AUC0–12 65 µg*h ml−1 (range 37–130) vs. 37 µg*h ml−1 (range 7–120), P < 0.005). Low 12‐h IMPDH enzyme activity curve (AEC0–12) was associated with an increased frequency of gastrointestinal side‐effects (median IMPDH AEC0–12 43 nmol*h mg−1 protein h−1[range 12–67) vs. 75 nmol*h mg−1 protein h−1 (range 15–371), P < 0.01].

CONCLUSIONS Despite highly variable absorption data, an appropriate LSS might be estimated by MPA AUC0–4 and IMPDH AEC0–4 in renal transplant patients treated with EC‐MPS and CsA. Regarding adverse events, the suggested MPA‐target AUC0–12 from 30 to 60 µg*h ml−1 seems to be appropriate in renal allograft recipients.
DNER modulates adipogenesis of human adipose tissue‐derived mesenchymal stem cells via regulation of cell proliferation
Authors: Park J.‐R. , Jung J.‐W. , Seo M.‐S. , Kang S.‐K. , Lee Y.‐S. , Kang K.‐S.
Published: December 2009

Objectives:  In recent years, obesity has become a global epidemic, highlighting the necessity for basic research into mechanisms underlying growth of adipose tissue and differentiation of stem cells into adipocytes, in humans. For better understanding of cell signalling in adipogenesis, the role of DNER (delta/Notch‐like EGF‐related receptor) in adipogenic differentiation of human adipose tissue‐derived mesenchymal stem cells (hAMSC) was investigated.

Materials and methods:  To assess the role of DNER in hAMSC adipogenesis, hAMSCs were transfected with DNER small interfering RNA (siDNER). Real‐time quantitative reverse transcriptase polymerase chain reactions to assess expression levels of adipogenesis‐related genes regulated by siDNER, cell cycle and immunoblot analyses were performed.

Results:  First, it was determined that DNER mRNA was profoundly expressed in hAMSCs and reduced during adipogenic differentiation. Knockdown of DNER altered cell morphology, inhibited proliferation and increased frequency and efficiency of adipogenesis in hAMSC. Expression of CCAAT/enhancer‐binding protein δ increased and proportion of cells in S phase decreased by knockdown of DNER, using specific siRNA. Moreover, adipocyte‐specific genes including peroxisome proliferator‐activated receptor gamma, fatty acid binding protein 4 and perilipin were up‐regulated in siDNER compared to the siControl group during adipogenesis in hAMSC.

Conclusions:  These results indicate that DNER knockdown in hAMSC accelerated onset of adipogenic differentiation by bypassing mitotic clonal expansion during the early stages of adipogenesis.
Alpha‐lipoic acid improves vascular endothelial function in patients with type 2 diabetes: a placebo‐controlled randomized trial
Authors: Heinisch B. B. , Francesconi M. , Mittermayer F. , Schaller G. , Gouya G. , Wolzt M. , Pleiner J.
Published: December 2009

Eur J Clin Invest 2010; 40 (2): 148–154

Objective  The aim of this study was to investigate the effect of alpha‐lipoic acid (ALA) treatment on endothelium‐dependent and ‐independent vasodilatation, assessed by forearm blood flow (FBF), in patients with type 2 diabetes mellitus.

Research design and methods  A total of 30 subjects with type 2 diabetes were included in this randomized, controlled, double‐blinded, parallel group study. FBF responses to intra‐arterial acetylcholine (ACh) and glycerol trinitrate (GTN) were measured before and after 21 days of intravenous treatment with 600 mg alpha‐lipoic acid or placebo.

Results  FBF responses were comparable at baseline. After treatment, FBF reactivity to ACh and GTN was unchanged in subjects receiving placebo. By contrast, ALA treatment increased endothelium‐dependent vasodilatation to ACh (P < 0·05) but not to GTN compared with baseline.

Conclusions  Intravenous ALA treatment improves endothelium‐dependent vasodilatation in patients with type 2 diabetes, in the absence of effects on forearm vasomotor function. If this salutary action translates into vascular risk reduction remains to be established.
Elevated serum dehydroepiandrosterone sulphate level correlates with increased risk for metabolic syndrome in the elderly men
Authors: Chen Y. C. , Chang H. H. , Wen C. J. , Lin W. Y. , Chen C. Y. , Hong B. S. , Huang K. C.
Published: December 2009

Eur J Clin Invest 2010; 40 (3): 220–225

Background  The previous studies regarding the association between endogenous dehydroepiandrosterone (DHEA) sulphate level and metabolic syndrome are inconsistent. This study aimed to investigate such relationship in elderly Taiwanese men.

Materials and methods  Five hundred and eighty‐five elderly Taiwanese men (mean age 68·7 ± 8·3 years) were enrolled as the baseline cohort population in 2000. In addition to a questionnaire, body mass index (BMI), blood pressure, fasting blood glucose, lipids, albumin and serum DHEA‐S levels were measured for each participant. Metabolic syndrome was based on the definition by the America Heart Association/National Heart Lung Blood Institute.

Results  The prevalence of metabolic syndrome was 33·3%. Using multivariate logistic regression analyses with adjustments for age, smoking, alcohol, physical activities, albumin and BMI, there was a positive relationship between serum DHEA‐S level and metabolic syndrome. The highest DHEA‐S quartile group had increased risk for metabolic syndrome (odds ratio = 2·68, 95% confidence interval: 1·44–5·01, P < 0·01) compared with the lowest quartile group. The mean serum DHEA‐S level increased with increasing number of metabolic syndrome components.

Conclusions  The prevalence of metabolic syndrome increases with elevated DHEA‐S levels among elderly Taiwanese men. Thus, elevated serum DHEA‐S level should be treated as an important risk factor for metabolic syndrome in elderly men.
Favourable habitats for Coffea inter‐specific hybridization in central New Caledonia: combined genetic and spatial analyses
Authors: Gomez Céline , Batti Ahmed , Le Pierrès Daniel , Campa Claudine , Hamon Serge , De Kochko Alexandre , Hamon Perla , Huynh Frédéric , Despinoy Marc , Poncet Valérie
Published: December 2009

1. Human disturbance of natural habitats has increasingly promoted hybridization between previously isolated species. Coffee trees (Coffea canephora, C. liberica and C. arabica) have been introduced into New Caledonia for cultivation since the 1850s. Many plantations have since been abandoned, leaving the cultivars to evolve in natural conditions. This historical situation and the local environmental conditions have led to gene flow between sympatric species and the creation of hybrid zones which can be considered as a natural laboratory for studying gene flow dynamics. Our objectives were to assess the nature of these hybridizations and to model the distribution of habitats favourable for these hybrid zones at a regional scale.

2. We analysed a tri‐specific model population with 26 microsatellite markers using a multilocus analysis approach. We applied Bayesian methods to characterize the species identity of founder individuals and identify inter‐specific hybrids. A high level of genetic diversity and inter‐specific hybridization was observed in the population. To evaluate the presence of other favourable environments in the local area, a geographic information system was used to spatially differentiate the phenomenon and optimize future hybrid collecting missions. We constructed a predictive distribution model based on observation and environmental expertise (climatic parameters, physical parameters and landcover) at four reference sites of the hybrid zone.

3. At all four sites the Coffea species were found to be involved in inter‐specific hybridization, with one population, in particular, revealing high genetic diversity. According to the environmental expertise, 40% of the studied region appeared to be favourable for this phenomenon and the model was validated with a prediction accuracy of 79%.

4. Synthesis and applications. The use of microsatellite markers was efficient for assessing the nature and extent of coffee tree hybridization events. The environmental expertise and model allowed comparisons between New Caledonia and Africa ecological niches. This methodology may be recommended for better management of de novo in situ coffee genetic resources and applied to other plants to provide insight into the impact of adaptation to new environment. Combining environmental and species biological parameters would help in analysing modifications in plant reproductive behaviour induced by global climate change.
Physical activity and sleep among pregnant women
Authors: Borodulin Katja , Evenson Kelly R. , Monda Keri , Wen Fang , Herring Amy H. , Dole Nancy
Published: December 2009

Borodulin K, Evenson KR, Monda K, Wen F, Herring AH, Dole N. Physical activity and sleep among pregnant women. Paediatric and Perinatal Epidemiology 2010; 24: 45–52.

Sleep disturbances are common among pregnant women and safe treatments to improve sleep are needed. Generally, physical activity improves sleep, but studies are lacking on the associations of physical activity with sleep among pregnant women. Our aim was to investigate the cross‐sectional association of various modes of physical activity and activity clusters with sleep quality and duration among 1259 pregnant women. Participants were recruited into the Pregnancy, Infection, and Nutrition Study from prenatal clinics at the University of North Carolina Hospitals. Women self‐reported sleep quality and duration and physical activity in the past week. We used cluster analysis to create seven physical activity profiles and multivariable logistic regression analysis, with adjustments for age, race/ethnicity, education, marital status, parity, self‐rated general health, anxiety and depressive symptoms.

Women with higher levels of occupational physical activity were more likely to report either short or normal sleep duration than longer duration. Women with higher levels of indoor household physical activity were less likely to report normal sleep duration than shorter duration. Women in the recreational‐indoor household activity cluster were less likely than women in the inactivity cluster to report normal sleep duration as compared with longer duration. Our data suggest weak associations of physical activity with sleep duration and quality in late pregnancy. Physical activity is recommended to pregnant women for health benefits, yet more research is needed to understand if physical activity should be recommended for improving sleep.
Impact of the Jamaican birth cohort study on maternal, child and adolescent health policy and practice
Authors: McCaw‐Binns A , Ashley D , Samms‐Vaughan M
Published: December 2009

McCaw‐Binns A, Ashley D, Samms‐Vaughan M. Impact of the Jamaican birth cohort study on maternal, child and adolescent health policy and practice. Paediatric and Perinatal Epidemiology 2010; 24: 3–11.

The Jamaica Perinatal Morbidity and Mortality Survey (JPMMS) was a national study designed to identify modifiable risk factors associated with poor maternal and perinatal outcome. Needing to better understand factors that promote or retard child development, behaviour and academic achievement, we conducted follow‐up studies of the birth cohort. The paper describes the policy developments from the JPMMS and two follow‐up rounds. The initial study (1986–87) documented 94% of all births and their outcomes on the island over 2 months (n = 10 508), and perinatal (n = 2175) and maternal deaths (n = 62) for a further 10 months. A subset of the birth cohort, identified by their date of birth through school records, was seen at ages 11–12 (n = 1715) and 15–16 years (n = 1563).

Findings from the initial survey led to, inter alia, clinic‐based screening for syphilis, referral high‐risk clinics run by visiting obstetricians, and the redesign and construction of new labour wards at referral hospitals. The follow‐up studies documented inadequate academic achievement among boys and children attending public schools, and associations between under‐ and over‐nutrition, excessive television viewing (>20 h/week), inadequate parental supervision and behavioural problems. These contributed to the development of a television programming code for children, a National Parenting Policy, policies aimed at improving inter‐sectoral services to children from birth to 5 years (Early Childhood Commission) and behavioural interventions of the Violence Prevention Alliance (an inter‐sectoral NGO) and the Healthy Lifestyles project (Ministry of Health). Indigenous maternal and child health research provided a local evidence base that informed public policy. Collaboration, good communication, being vigilant to opportunities to influence policy, and patience has contributed to our success.
Reliability of variables on the North Carolina birth certificate: a comparison with directly queried values from a cohort study
Authors: Vinikoor Lisa C. , Messer Lynne C. , Laraia Barbara A. , Kaufman Jay S.
Published: December 2009

Vinikoor LC, Messer LC, Laraia BA, Kaufman JS. Reliability of variables on the North Carolina birth certificate: a comparison with directly queried values from a cohort study. Paediatric and Perinatal Epidemiology 2010; 24: 102–112.

Birth records are an important source of data for examining population‐level birth outcomes, but questions about the reliability of these vital records exist. We sought to assess the reliability of birth certificate data by comparing them with data from a large prospective cohort. Pregnancy, Infection, and Nutrition cohort study participants were matched with their birth certificates to assess agreement for maternal demographics, health behaviours, previous pregnancies and major pregnancy events. Agreement among categorical variables was assessed using percentage agreement and kappa statistics; for continuous variables, Spearman's correlations and concordance correlation coefficients were used.

The majority of variables had high agreement between the two data sources, especially for maternal demographic and birth outcome variables. Variables measuring anaemia, gestational diabetes and alcohol consumption showed the lowest correlations. Number of cigarettes smoked and number of previous pregnancies differed by education categories. For most variables, birth records appear to be a good source of reliable information. With the exception of a few variables that differed by education, most variables did not differ by stratum of race or education. Our research further supports the use of birth certificates as a reliable source of population‐level data.
Effects of calcium supplementation on fetal growth in mothers with deficient calcium intake: a randomised controlled trial
Authors: Abalos Edgardo , Merialdi Mario , Wojdyla Daniel , Carroli Guillermo , Campodónico Liana , Yao Shih‐Ern , Gonzalez Rogelio , Deter Russell , Villar José , Van Look Paul
Published: December 2009

Abalos E, Merialdi M, Wojdyla D, Carroli G, Campodónico L, Yao S‐E, Gonzalez R, Deter R, Villar J, Van Look P. Effects of calcium supplementation on fetal growth in mothers with deficient calcium intake: a randomised controlled trial. Paediatric and Perinatal Epidemiology 2010; 24: 53–62.

Calcium supplementation in mothers with low calcium intake has been of interest recently because of its association with optimal fetal growth and improved pre‐eclampsia‐related outcomes. While the effects of calcium supplementation have demonstrated benefits in prolonging gestation and subsequently improving birthweight, no specific studies have identified the longitudinal effects of supplementation on fetal growth in utero. Data were analysed in the context of the World Health Organization trial of calcium supplementation in calcium‐deficient women. Five hundred and ten healthy, primiparous pregnant Argentinean women were randomised (at <20 weeks gestation) to either placebo (n = 230) or calcium supplements (1500 mg calcium/day in 3 divided doses; n = 231). Growth parameters in utero were assessed with serial ultrasound scans. Birthweight, length, head, abdominal and thigh circumferences were recorded at delivery.

No differences were found in fetal biometric measurements recorded at 20, 24, 28, 32 and 36 weeks gestation between fetuses of women who were supplemented with calcium and those who were not. Similarly, neonatal characteristics and anthropometric measurements recorded at delivery were comparable in both groups. We conclude that calcium supplementation of 1500 mg calcium/day in pregnant women with low calcium intake does not appear to impact on fetal somatic or skeletal growth.
Very preterm birth: who has access to antenatal corticosteroid therapy?
Authors: Burguet Antoine , Ferdynus Cyril , Thiriez Gérard , Bouthet Marie‐France , Kayemba‐Kays Simon , Sanyas Paul , Menget Alain , Mulin Blandine , Riethmuller Didier , Maillet Robert , Brousse Claire , Magnin Guillaume , Boisselier Philippe , Sagot Paul , Pierre Fabrice , Gouyon Béatrice , Gouyon Jean‐Bernard
Published: December 2009

Burguet A, Ferdynus C, Thiriez G, Bouthet M‐F, Kayemba‐Kays S, Sanyas P, Menget A, Mulin B, Riethmuller D, Maillet R, Brousse C, Magnin G, Boisselier P, Sagot P, Pierre F, Gouyon B, Gouyon J‐B. Very preterm birth: who has access to antenatal corticosteroid therapy? Paediatric and Perinatal Epidemiology 2010; 24: 63–74.

We describe the administration of antenatal corticosteroid therapy (ACT) for liveborn very preterm neonates in a population‐based study. A total of 790 very preterm neonates (between 24 and 31 full weeks of gestation) were included in this regionally defined population of very preterm neonates in France. The main outcome measure was non‐access to ACT. Data were analysed using logistic and polytomous models to control for neonatal and sociodemographic characteristics, mechanisms of very preterm birth and neonatal network organisation.

As compared with level III, births in levels I‐II maternity units were closely related to non‐access to ACT (60.1% vs. 8.8%), but not to pregnancy follow‐up (19.7% vs. 17.8%). Only 6.3% of very preterm neonates that benefited from antepartum referral did nor receive ACT. Births associated with rupture of membranes and gestational hypertension were significantly more often transferred to level‐III units (73.8% and 68.3% respectively) than those due to maternal bleeding and spontaneous labour (57.0% and 50.7% respectively), and the neonates had a lower probability of not receiving ACT (8.5%, 11.5%, 23.0%, 31.2% respectively). Very preterm neonates referred in utero to a level‐III unit came from a more favourable socio‐economic environment. Non‐access to ACT was more often observed in neonates born to 14‐ to 24‐year‐old mothers, smokers, of low socio‐economic status, and preterm birth resulting from maternal bleeding or spontaneous labour.

These data from a French regional study show that access to ACT is not only explained by practitioners' support of recommendations. In our population‐based study, ACT access was related to socio‐economic factors and to the mechanisms of very preterm birth. Improving the rate of access to ACT should take these organisational, medical and socio‐economic dimensions into account.
Violent delinquency in a Brazilian birth cohort: the roles of breast feeding, early poverty and demographic factors
Authors: Caicedo Beatriz , Gonçalves Helen , González David A. , Victora Cesar G.
Published: December 2009

Caicedo B, Gonçalves H, González DA, Victora CG. Violent delinquency in a Brazilian birth cohort: the roles of breast feeding, early poverty and demographic factors. Paediatric and Perinatal Epidemiology 2010; 24: 12–23.

We investigated the association between breast feeding, economic factors and conviction for violent delinquency by age 25 years among subjects of the 1982 Birth Cohort from Pelotas, Southern Brazil. Information on breast‐feeding pattern and duration was collected in childhood, during the 1983, 1984 and 1986 follow‐ups. Information on socio‐economic and family characteristics was also obtained between 1982 and 1996. Of the 5914 livebirths enrolled in the cohort, 5228 had obtained an identification document within the state of Rio Grande do Sul, and could thus be identified in judiciary databases. The outcome studied was conviction due to a violent act between ages 12 and 25 years. A total of 106 young people had been convicted at least once (3.0% of men and 1.0% of women). Subjects born to black or mixed mothers and coming from low‐income families were at higher risk of having been convicted. Neither crude nor adjusted analyses showed any association between breast feeding and conviction for violent delinquency. Violent delinquency apparently depends more on social factors than on individual factors such as breast feeding.
Serum level of immunoglobulin E during pregnancy – does offspring sex matter?
Authors: Løken Mari Overn , Jeansson Stig , Jenum Pål A. , Eskild Anne
Published: December 2009

Løken MO, Jeansson S, Jenum PA, Eskild A. Serum level of immunoglobulin E during pregnancy – does offspring sex matter? Paediatric and Perinatal Epidemiology 2010; 24: 75–78.

We assessed maternal serum levels of total immunoglobulin E (IgE) in the first, second and third trimester and changes in total IgE levels from first to third trimester in relation to offspring sex. Within a cohort of 29 948 pregnant women, 392 women without a history of pre‐eclampsia and with a liveborn child were randomly selected. Information on offspring sex was obtained through linkage to the Medical Birth Registry of Norway. Blood samples from each trimester were analysed for total IgE concentration. Differences in mean levels according to offspring sex were estimated and changes in total IgE levels from first to third trimester were assessed.

In all three trimesters there was a tendency of women carrying a male fetus to have a higher mean total IgE level, but significant statistical differences were not reached. The total IgE concentration decreased during pregnancy, but the decrement was less in women carrying a male fetus compared with those who carried a female fetus.
Species‐specific activation time‐lags can explain habitat restrictions in hydrophilic lichens
Authors: LIDÉN MARLENE , JONSSON ČABRAJIĆ ANNA V. , OTTOSSON‐LÖFVENIUS MIKAELL , PALMQVIST KRISTIN , LUNDMARK TOMAS
Published: December 2009

Photosystem II (PSII) activation after hydration with water or humid air was measured in four hydrophilic and a generalist lichen to test the hypothesis that slow activation might explain habitat restriction in the former group. For the hydrophilic species, activation was after 4 h nearly completed in Lobaria amplissima and Platismatia norvegica, while only c. 50% for Bryoria bicolor and Usnea longissima. The generalist Platismatia glauca was activated instantaneously. The effect of this on lichen field performance was investigated using a dynamic model separating the two water sources rain and humid air. Model simulations were made using the species‐specific characteristics and climate data from 12 stream microhabitats. For U. longissima, slow PSII activation could reduce realized photosynthesis by a factor of five. Bryoria bicolor was almost as severely affected, while P. norvegica displayed moderate reductions. Lobaria amplissima displayed longer realized activity periods even in unfavourable microclimates, possibly because of a higher water loss resistance. Both close proximity to streams and presence of turbulent water had a positive impact on realized activity among the slowly activated species, coinciding with observed distribution patterns of hydrophilic species. The results presented here may thus partly explain observed habitat restrictions of rare hydrophilic lichens.
Do photosynthetic limitations of evergreen Quercus ilex leaves change with long‐term increased drought severity?
Authors: LIMOUSIN JEAN‐MARC , MISSON LAURENT , LAVOIR ANNE‐VIOLETTE , MARTIN NICOLAS K. , RAMBAL SERGE
Published: December 2009

Seasonal drought can severely impact leaf photosynthetic capacity. This is particularly important for Mediterranean forests, where precipitation is expected to decrease as a consequence of climate change. Impacts of increased drought on the photosynthetic capacity of the evergreen Quercus ilex were studied for two years in a mature forest submitted to long‐term throughfall exclusion. Gas exchange and chlorophyll fluorescence were measured on two successive leaf cohorts in a control and a dry plot. Exclusion significantly reduced leaf water potential in the dry treatment. In both treatments, light‐saturated net assimilation rate (Amax), stomatal conductance (gs), maximum carboxylation rate (Vcmax), maximum rate of electron transport (Jmax), mesophyll conductance to CO2 (gm) and nitrogen investment in photosynthesis decreased markedly with soil water limitation during summer. The relationships between leaf photosynthetic parameters and leaf water potential remained identical in the two treatments. Leaf and canopy acclimation to progressive, long‐term drought occurred through changes in leaf area index, leaf mass per area and leaf chemical composition, but not through modifications of physiological parameters.
Genotypic diversity in Fusarium pseudograminearum populations in Australian wheat fields
Authors: Scott J. B. , Chakraborty S.
Published: December 2009

Despite being closely related to Fusarium graminearum, which has been extensively characterized in many countries around the world, the population biology of Fusarium pseudograminearum, the main causal agent of crown rot of wheat in Australia and many other wheat‐growing regions, has been comparatively poorly studied to date. A simple sequence repeat analysis of 163 F. pseudograminearum isolates from three field sites in NSW, Australia identified 128 distinct multilocus genotypes. Observed genetic diversity within fields was high, whilst genetic variation between fields was low. Across all fields genetic linkage disequilibrium was detected, but of the three individual fields, only one also displayed linkage disequilibrium. These results indicate that the isolates obtained were part of the same, highly diverse, population. However, this population may not be freely interbreeding. Whilst isolation incidence of F. pseudograminearum was found to be spatially aggregated within fields, spatial aggregation of genotypes within fields was weak. The study suggests that processes influencing population dynamics may operate at a scale larger than the narrow geographical scale covered in the fields sampled.
Interactions of four pathotypes of Diplocarpon rosae with species and hybrids of Rosa
Authors: Allum J. F. , Bringloe D. H. , Roberts A. V.
Published: December 2009

The interactions of four pathotypes of Diplocarpon rosae with 34 species and hybrids of Rosa were compared in an ongoing search for criteria of potential relevance to rose breeding. There were greater similarities in the resistance‐susceptibility interactions of these roses to the pathotypes DA1, CW1 and ZM1, than to a fourth pathotype, DA2. Among the species roses, only those of the section Cinnamomeae were susceptible to DA2 and this susceptibility was transmitted in several cases to hybrid progeny. CW1 had the greatest pathogenicity of the four pathotypes. In a cross between R. rugosa cv. Scabrosa, which was resistant and R. rugosa f. alba, which was susceptible to all pathotypes, the progeny were tested for resistance to pathotypes DA1, CW1 and ZM1. Each of the 20 progeny was susceptible to all three pathotypes. This shows that, unlike the well characterized Rdr1 gene for resistance to D. rosae, the resistance of R. rugosa cv. Scabrosa is not determined by a dominant major gene. The diploid hybrid, R. rugosa cv. Martin Frobisher × cv. Mistress Quickly, was resistant to all four pathotypes, but an induced tetraploid of this hybrid was susceptible to all pathotypes. The relevance of these findings to the breeding of roses for resistance to black spot disease is discussed.
Behavioural differences between male and female carpenter bees in nectar robbing and its effect on reproductive success in Glechoma longituba (Lamiaceae)
Authors: Zhang Y.‐W. , Zhao J.‐M. , Yang C.‐F. , Gituru W. R.
Published: December 2009

Male and female nectar robbers may show significantly different behaviour on host plants and thus have different impacts on reproductive fitness of the plants. A 4‐year study in natural populations of Glechoma longituba has shown that male carpenter bees (Xylocopa sinensis) are responsible for most of the nectar robbing from these flowers, while female bees account for little nectar robbing, demonstrating distinct behavioural differentiation between male and female bees in visiting flowers. The smaller male bee spends less time visiting a single flower than the larger female bee, consequently, the male bee is capable of visiting more flowers per unit time and has a higher foraging efficiency. Moreover, the robbing behaviour of female carpenter bees is more destructive and affects flower structures (ovules and nectaries) and floral life‐span more than that of the male bee. According to the energy trade‐off hypothesis, the net energy gain for male bees during nectar robbing greatly surpasses energy payout (17.72 versus 2.43 J), while the female bee net energy gain is barely adequate to meet energy payout per unit time (3.78 versus 2.39 J). The differences in net energy gain for male and female bees per unit time in nectar robbing are the likely cause of observed behavioural differences between the sexes. The differences in food resource preference between male and female bees constitute an optimal resource allocation pattern that enables the visitors to utilise floral resources more efficiently.
Salinity tolerance of Populus
Authors: Chen S. , Polle A.
Published: December 2009

The genus Populus has a wide distribution in different climatic zones. Besides its economic and ecological relevance, Populus also serves as a model for elucidating physiological and molecular mechanisms of stress tolerance in tree species. In this review, adaptation strategies of poplars to excess soil salinity are addressed at different scales, from the cellular to the whole‐plant level. Striking differences in salt tolerance exist among different poplar species and ecotypes, with Populus euphratica being outstanding in this respect. Key mechanisms identified in this species to mediate salt tolerance are compartmentalisation of Cl− in the vacuoles of the root cortex cells, diminished xylem loading of NaCl, activation of Na+ extrusion into the soil solution under stress, together with simultaneously avoiding excessive K+ loss by regulation of depolarisation‐activated cation channels. This leads to improved maintenance of the K+/Na+ balance, a crucial precondition for survival under salt stress. Leaf cells of this species are able to compartmentalise Na+ preferentially in the apoplast, whereas in susceptible poplar species, as well as in crop plants, vacuolar Na+ deposition precedes apoplastic transport. ABA, Ca2+and ROS are involved in stress sensing, with higher or faster activation of defences in tolerant than in susceptible poplar species. P. euphratica develops leaf succulence after prolonged salt exposure as a plastic morphological adaptation that leads to salt dilution. Transgenic approaches to improve salt tolerance by transformation of candidate genes have had limited success, since salt tolerance is a multigenic trait. In future attempts towards increased salt resistance, barriers between different poplar sections must be overcome and application of novel biotechnological tools, such as gene stacking, are recommended.