Reconnection-Driven Magnetohydrodynamic Turbulence in a Simulated Coronal-Hole Jet

Extreme-ultraviolet and X-ray jets occur frequently in magnetically open coronal holes on the Sun, especially at high solar latitudes. Some of these jets are observed by white-light coronagraphs as they propagate through the outer corona toward the inner heliosphere, and it has been proposed that they give rise to microstreams and torsional Alfven waves detected in situ in the solar wind. To predict and understand the signatures of coronal-hole jets, we have performed a detailed statistical analysis of such a jet simulated with an adaptively refined magnetohydrodynamics model. The results confirm the generation and persistence of three-dimensional, reconnection-driven magnetic turbulence in the simulation. We calculate the spatial correlations of magnetic fluctuations within the jet and find that they agree best with the Meuller - Biskamp scaling model including intermittent current sheets of various sizes coupled via hydrodynamic turbulent cascade. The anisotropy of the magnetic fluctuations and the spatial orientation of the current sheets are consistent with an ensemble of nonlinear Alfven waves. These properties also reflect the overall collimated jet structure imposed by the geometry of the reconnecting magnetic field. A comparison with Ulysses observations shows that turbulence in the jet wake is in quantitative agreement with that in the fast solar wind

Surfactant status and respiratory outcome in premature infants receiving late surfactant treatment.

BACKGROUND:Many premature infants with respiratory failure are deficient in surfactant, but the relationship to occurrence of bronchopulmonary dysplasia (BPD) is uncertain. METHODS:Tracheal aspirates were collected from 209 treated and control infants enrolled at 7-14 days in the Trial of Late Surfactant. The content of phospholipid, surfactant protein B, and total protein were determined in large aggregate (active) surfactant. RESULTS:At 24 h, surfactant treatment transiently increased surfactant protein B content (70%, p < 0.01), but did not affect recovered airway surfactant or total protein/phospholipid. The level of recovered surfactant during dosing was directly associated with content of surfactant protein B (r = 0.50, p < 0.00001) and inversely related to total protein (r = 0.39, p < 0.0001). For all infants, occurrence of BPD was associated with lower levels of recovered large aggregate surfactant, higher protein content, and lower SP-B levels. Tracheal aspirates with lower amounts of recovered surfactant had an increased proportion of small vesicle (inactive) surfactant. CONCLUSIONS:We conclude that many intubated premature infants are deficient in active surfactant, in part due to increased intra-alveolar metabolism, low SP-B content, and protein inhibition, and that the severity of this deficit is predictive of BPD. Late surfactant treatment at the frequency used did not provide a sustained increase in airway surfactant

The time-averaged paleomagnetic field

We review indications of persistent deviations from the geocentric axial dipole model of the time-averaged geomagnetic field and present a zonal harmonic model derived from 185 deep-sea sediment piston cores taken from low to middle latitudes (to approximately ±45°). Analysis of the paleomagnetic inclination recorded in these cores for the Brunhes (normal polarity; 0-73 Ma) and Matuyama (reverse polarity; 0.73-2.47 Ma) chrons, after plate motion correction, gives well-constrained estimates of the dominant long-term nondipole contributions (the axial quadrupole and axial octupole) and shows no significant deviation from axial symmetry. The amplitude of the axial quadrupole is found to vary with polarity (2.6% of the geocentric axial dipole for normal; 4.6% for reverse), while the axial octupole does not show appreciable change (-2.9% for normal; -2.1% for reverse). These estimates of the quadrupole contribution agree well with prior determinations for the Plio-Pleistocene (0-5 Ma); however, the octupole contribution we find is opposite in sign to previous estimates. We suggest that a negative octupole is representative of the actual time-averaged paleomagnetic field, while prior positive octupole estimates probably reflect spurious inclination shallowing. The lack of polarity asymmetry in the octupole suggests that this nondipole component may be more closely linked to the main dipole field than is the quadrupole and so supports models of the geodynamo in which dipole and quadrupole families do not interact

The association of AGTR2 polymorphisms with preeclampsia and uterine artery bilateral notching is modulated by maternal BMI

On behalf of the SCOPE consortiumIntroductionThis study aimed to determine the association of AGTR1 and AGTR2 polymorphisms with preeclampsia and whether these are affected by environmental factors and fetal sex.MethodsOverall 3234 healthy nulliparous women, their partners and babies were recruited prospectively to the SCOPE study in Adelaide and Auckland. Data analyses were confined to 2121 Caucasian parent-infant trios, among whom 123 had preeclamptic pregnancies. 1185 uncomplicated pregnancies served as controls. DNA was extracted from buffy coats and genotyped by utilizing the Sequenom MassARRAY system. Doppler sonography on the uterine arteries was performed at 20 weeks' gestation.ResultsFour polymorphisms in AGTR1 and AGTR2 genes, including AGTR1 A1166C, AGTR2 C4599A, AGTR2 A1675G and AGTR2 T1134C, were selected and significant associations were predominately observed for AGTR2 C4599A. When the cohort was stratified by maternal BMI, in women with BMI ≥ 25 kg/m(2), the AGTR2 C4599A AA genotype in mothers and neonates was associated with an increased risk for preeclampsia compared with the CC genotype [adjusted OR 2.1 (95% CI 1.0-4.2) and adjusted OR 3.0 (95% CI 1.4-6.4), respectively]. In the same subset of women, paternal AGTR2 C4599A A allele was associated with an increased risk for preeclampsia and uterine artery bilateral notching at 20 weeks' gestation compared with the C allele [adjusted OR 1.9 (95% CI 1.1-3.3) and adjusted OR 2.1 (95% CI 1.3-3.4), respectively].ConclusionAGTR2 C4599A in mothers, fathers and babies was associated with preeclampsia and this association was only apparent in pregnancies in which the women had a BMI ≥ 25 kg/m(2), suggesting a gene-environment interaction.A. Zhou, G.A. Dekker, E.R. Lumbers, S.Y. Lee, S.D. Thompson, L.M.E. McCowan, C.T. Robert

Deep-tow magnetic anomaly study of the Pacific Jurassic Quiet Zone and implications for the geomagnetic polarity reversal timescale and geomagnetic field behavior

Author Posting. © American Geophysical Union, 2008. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 113 (2008): B07110, doi:10.1029/2007JB005527.The Jurassic Quiet Zone (JQZ) is a region of low-amplitude magnetic anomalies whose distinctive character may be related to geomagnetic field behavior. We collected deep-tow magnetic profiles in Pigafetta Basin (western Pacific) where previous deep-tow data partially covered the JQZ sequence. Our goals were to extend the survey through the JQZ, examine anomaly correlations, and refine a preliminary geomagnetic polarity timescale (GPTS) model. We collected a series of closely spaced profiles over anomaly M34 and Ocean Drilling Program Hole 801C to examine anomaly correlation in detail, one profile in between previous profiles, and two long profiles extending the survey deeper into the JQZ. Anomaly features can be readily correlated except in a region of low-amplitude, short-wavelength anomalies in the middle of the survey area (“low-amplitude zone” or LAZ). The small multiprofile surveys demonstrate anomaly linearity, implying that surrounding anomalies are also linear and likely result from crustal recording of geomagnetic field changes. We constructed a GPTS model assuming that most anomalies result from polarity reversals. The polarity timescale is similar to the polarity sequences from previous studies, but its global significance is uncertain because of problems correlating anomalies in the LAZ and the ambiguous nature of the small JQZ anomalies. Overall anomaly amplitude decreases with age into the LAZ and then increases again, implying low geomagnetic field strength, perhaps related to a rapidly reversing field. Other factors that may contribute to the LAZ are interference of anomalies over narrow, crustal polarity zones and poorly understood local tectonic complexities.This research was supported by the National Science Foundation grants OCE-0099161 and OCE-0099237. Tominaga was partly supported by funds from the Jane and R. Ken Williams ’45 Chair in Ocean Drilling Science, Education, and Technology

Common Variants at 10 Genomic Loci Influence Hemoglobin A(1C) Levels via Glycemic and Nonglycemic Pathways

OBJECTIVE Glycated hemoglobin (HbA1c), used to monitor and diagnose diabetes, is influenced by average glycemia over a 2- to 3-month period. Genetic factors affecting expression, turnover, and abnormal glycation of hemoglobin could also be associated with increased levels of HbA1c. We aimed to identify such genetic factors and investigate the extent to which they influence diabetes classification based on HbA1c levels. RESEARCH DESIGN AND METHODS We studied associations with HbA1c in up to 46,368 nondiabetic adults of European descent from 23 genome-wide association studies (GWAS) and 8 cohorts with de novo genotyped single nucleotide polymorphisms (SNPs). We combined studies using inverse-variance meta-analysis and tested mediation by glycemia using conditional analyses. We estimated the global effect of HbA1c loci using a multilocus risk score, and used net reclassification to estimate genetic effects on diabetes screening. RESULTS Ten loci reached genome-wide significant association with HbA1c, including six new loci near FN3K (lead SNP/P value, rs1046896/P = 1.6 × 10−26), HFE (rs1800562/P = 2.6 × 10−20), TMPRSS6 (rs855791/P = 2.7 × 10−14), ANK1 (rs4737009/P = 6.1 × 10−12), SPTA1 (rs2779116/P = 2.8 × 10−9) and ATP11A/TUBGCP3 (rs7998202/P = 5.2 × 10−9), and four known HbA1c loci: HK1 (rs16926246/P = 3.1 × 10−54), MTNR1B (rs1387153/P = 4.0 × 10−11), GCK (rs1799884/P = 1.5 × 10−20) and G6PC2/ABCB11 (rs552976/P = 8.2 × 10−18). We show that associations with HbA1c are partly a function of hyperglycemia associated with 3 of the 10 loci (GCK, G6PC2 and MTNR1B). The seven nonglycemic loci accounted for a 0.19 (% HbA1c) difference between the extreme 10% tails of the risk score, and would reclassify ∼2% of a general white population screened for diabetes with HbA1c. CONCLUSIONS GWAS identified 10 genetic loci reproducibly associated with HbA1c. Six are novel and seven map to loci where rarer variants cause hereditary anemias and iron storage disorders. Common variants at these loci likely influence HbA1c levels via erythrocyte biology, and confer a small but detectable reclassification of diabetes diagnosis by HbA1c

Protocol for a randomised controlled trial examining the impact of a web-based personally controlled health management system on the uptake of influenza vaccination rates

<p>Abstract</p> <p>Background</p> <p>Online social networking and personally controlled health management systems (PCHMS) offer a new opportunity for developing innovative interventions to prevent diseases of public health concern (e.g., influenza) but there are few comparative studies about patterns of use and impact of these systems.</p> <p>Methods/Design</p> <p>A 2010 CONSORT-compliant randomised controlled trial with a two-group parallel design will assess the efficacy of a web-based PCHMS called <it>Healthy.me </it>in facilitating the uptake of influenza vaccine amongst university students and staff. Eligible participants are randomised either to obtain access to <it>Healthy.me </it>or a 6-month waitlist. Participants complete pre-study, post-study and monthly surveys about their health and utilisation of health services. A post-study clinical audit will be conducted to validate self-reports about influenza vaccination and visits to the university health service due to influenza-like illness (ILI) amongst a subset of participants. 600 participants older than 18 years with monthly access to the Internet and email will be recruited. Participants who (i) discontinue the online registration process; (ii) report obtaining an influenza vaccination in 2010 before the commencement of the study; or (iii) report being influenced by other participants to undertake influenza vaccination will be excluded from analysis. The primary outcome measure is the number of participants obtaining influenza vaccination during the study. Secondary outcome measures include: number of participants (i) experiencing ILI symptoms, (ii) absent from or experiencing impairment in work or study due to ILI symptoms, (iii) using health services or medications due to ILI symptoms; (iv) expressing positive or negative attitudes or experiences towards influenza vaccination, via their reasons of receiving (or not receiving) influenza vaccine; and (v) their patterns of usage of <it>Healthy.me </it>(e.g., frequency and timing of hits, duration of access, uptake of specific functions).</p> <p>Discussion</p> <p>This study will provide new insights about the utility of online social networking and PCHMS for public health and health promotion. It will help to assess whether a web-based PCHMS, with connectivity to a health service provider, containing information and self-management tools, can improve the uptake of preventive health services amongst university students and staff.</p> <p>Trial registration</p> <p><a href="http://www.anzctr.org.au/ACTRN12610000386033.aspx">ACTRN12610000386033</a> (Australian New Zealand Clinical Trials Registry)</p

Fire models and methods to map fuel types: The role of remote sensing.

Understanding fire is essential to improving forest management strategies. More specifically, an accurate knowledge of the spatial distribution of fuels is critical when analyzing, modelling and predicting fire behaviour. First, we review the main concepts and terminology associated with forest fuels and a number of fuel type classifications. Second, we summarize the main techniques employed to map fuel types starting with the most traditional approaches, such as field work, aerial photo interpretation or ecological modelling. We pay special attention to more contemporary techniques, which involve the use of remote sensing systems. In general, remote sensing systems are low-priced, can be regularly updated and are less time-consuming than traditional methods, but they are still facing important limitations. Recent work has shown that the integration of different sources of information andmethods in a complementary way helps to overcome most of these limitations. Further research is encouraged to develop novel and enhanced remote sensing techniques