bluuebunny/crossref_metadata_2025 huggingface dataset:
Outcomes of pregnancies affected by hemoglobin H disease
Authors: Tongsong Theera , Srisupundit Kasemsri , Luewan Suchaya
Published: November 2008

Objective

To determine the outcomes of pregnancies affected by hemoglobin H (HbH) disease.

Methods

A retrospective cohort study was conducted with 120 women with singleton pregnancies complicated by HbH disease only. The controls‐to‐cases ratio was 2:1.

Results

Maternal outcomes were similar in the 2 groups. The incidences of fetal growth restriction (relative risk [RR], 2.4; 95% confidence interval [CI], 1.60–3.50), preterm birth (RR, 1.4; 95% CI, 1.03–1.96), and low birth weight (RR, 1.9; 95% CI, 1.46–2.56) were significantly higher in the study than in the control group. The perinatal mortality rate was slightly higher in the study group.

Conclusion

In spite of attempts to keep hemoglobin levels sufficiently high (> 7.0 g/dL), pregnancies with HbH disease were significantly associated with increased risks of fetal growth restriction, preterm birth, and low birth weight.
The association between dietary vitamin K intake and serum undercarboxylated osteocalcin is modulated by vitamin K epoxide reductase genotype
Authors: Nimptsch Katharina , Nieters Alexandra , Hailer Susanne , Wolfram Günther , Linseisen Jakob
Published: November 2008

Vitamin K acts as a cofactor during the γ-carboxylation of vitamin K-dependent proteins. Undercarboxylated osteocalcin (ucOC) is a suggested biomarker of vitamin K status. The +2255 polymorphism of the vitamin K epoxide reductase gene (VKORC1) was shown to be associated with the recycling rate of the active form of vitamin K. We investigated the association between dietary vitamin K intake and serum ucOC and hypothesized that this association might vary byVKORC1genotype. ucOC and total intact osteocalcin (iOC) concentrations were quantified using specific ELISA tests in serum samples of 548 male and female participants (aged 18–81 years) of the Bavarian Food Consumption Survey II. ucOC was expressed relative to iOC (ucOC/iOC ratio). Dietary intake of vitamin K (phylloquinone and menaquinones) was estimated from three 24 h dietary recalls using previously published food composition data. The association between dietary vitamin K intake and ucOC/iOC ratio was analysed using linear and non-linear regression models. Median intakes of phylloquinone/menaquinones were 83·4/37·6 μg/d in men and 79·6/29·8 μg/d in women, respectively. As expected, vitamin K intake was significantly inversely associated with the ucOC/iOC ratio. The ucOC/iOC ratio differed significantly across variants of the +2255 polymorphism in theVKORC1gene. Stratification byVKORC1+2255 genotype revealed that only in carriers of the GG genotype (39 % of all participants) did the ucOC/iOC ratio significantly decrease with increasing intake of vitamin K. Thus, the results show that the inverse association between dietary vitamin K intake and serum ucOC depends on a functionally relevant allelic variant of theVKORC1gene.
Brisk walking offsets the increase in postprandial TAG concentrations found when changing to a diet with increased carbohydrate
Authors: Burns Stephen F. , Hardman Adrianne E. , Stensel David J.
Published: November 2008

We tested the hypothesis that 30 min of brisk walking daily would offset the increase in plasma TAG concentrations associated with substituting dietary fat for carbohydrate. Fourteen subjects (six males) aged 57 (sd5) years underwent three 4 d trials in a counterbalanced order: (i) 4 d on a typical UK diet (40 % energy from fat, 45 % carbohydrate and 15 % protein); (ii) 4 d on an isoenergetic diet but substituting fat for carbohydrate in line with the present recommendations (30 % fat, 55 % carbohydrate and 15 % protein); (iii) 4 d on the same recommended diet with 30 min of brisk walking each day. The food provided for the first 3 d of each trial was isoenergetic with each volunteer's previously determined daily energy intake. On day 4, the subjects consumed breakfast, lunch and an early evening meal, equivalent in total to 90 % of their daily energy intake. Blood samples were collected and substrate utilisation and energy expenditure were determined in the fasted state and for 9 h postprandially. Substrate utilisation differed significantly among trials (P = 0·003); RER was higher on the recommended diet trial than during either of the other two trials (P = 0·012 and 0·021 for the UK diet and recommended diet with walking, respectively). The rise in plasma TAG concentrations over the day was steeper on the recommended diet trial than on the other two trials (trial × time interaction,P = 0·040). The increase in postprandial TAG concentrations associated with substituting dietary fat for carbohydrate was offset by 30 min of brisk walking daily.
Diagnosis of alveolar echinococcosis using immunoblotting with plural low molecular weight antigens
Authors: Yamano K. , Goto A. , Miyoshi M. , Furuya K. , Sawada Y. , Sato N.
Published: November 2008

Alveolar echinococcosis (AE) is endemic to Hokkaido, Japan. For the past 20 years, detection of AE among inhabitants has involved serological screening using an enzyme-linked immunosorbent assay (ELISA) followed by Western blotting (WB). Between the years 1987 and 2000, antigens targeted on 66, 55 and 30–35 kDa bands were routinely used in the WB step of AE diagnosis. However, since 2001 diagnosis has been dependent on three smaller molecular weight antigens (26–28, 18 and 7–8 kDa). Due to its higher sensitivity, this improved WB approach has been used as a confirmation step in the screening process and also for the testing of suspected AE cases in hospital outpatients. Using the improved WB technique, a total of 1745 serum samples were examined in 2001–2006 with 81 patients detected and registered with AE. Interestingly, sera from 76 of the 81 diagnosed AE patients (93.8%) demonstrated reactivity with all three antigens. However, sera from the remaining five patients (6.2%) demonstrated no reactivity with the 18 kDa antigen, even though they exhibited clearly detectable levels of reactivity with the 26–28 and 7–8 kDa bands. These results suggest that medical practitioners need to pay particular attention to the specific reactions to some different diagnostic antigens to minimize the risk of misdiagnosing AE patients. In turn, these results may also provide important diagnostic information for cystic echinococcosis (CE).
FETAL PAIN
Authors: VAN SCHELTEMA PHEBE N ADAMA , BAKKER SEM , VANDENBUSSCHE FPHA , OEPKES D
Published: November 2008

The concept of fetal pain is becoming more and more relevant since the possibilities for invasive intrauterine treatment are increasing. However, there is much debate as to whether the fetus is mature enough to be able to perceive pain. But what is ‘pain’? One cannot determine whether a fetus feels pain unless one has a conception of what pain is. There is a difference in opinion about what pain reallyisand that is also the difficulty in studies on fetal pain: we cannot simply ask the fetus whether or not it feels pain. We can only give indirect evidence of possible harmful effects of stressful stimuli on the developing fetus. In this review we will first explore the meaning of ‘pain’. We will then discuss fetal anatomic, neurophysiologic and behavioural development and the responses which are thought to be required to experience pain. Finally, we discuss some ethical considerations and suggestions on fetal anaesthesia.
A good-quality breakfast is associated with better mental health in adolescence
Authors: O’Sullivan Therese A , Robinson Monique , Kendall Garth E , Miller Margaret , Jacoby Peter , Silburn Sven R , Oddy Wendy H
Published: November 2008

Objective

Breakfast consumption has been associated with better mental health in adulthood, but the relationship between breakfast and mental health in adolescence is less well known. The aims of the present study were to evaluate breakfast quality in a cohort of adolescents and to investigate associations with mental health.

Design

Cross-sectional population-based study. Breakfast quality was assessed by intake of core food groups at breakfast, as determined from 3 d food diaries. Mental health was assessed using the Child Behaviour Checklist (CBCL), with higher scores representing poorer behaviour.

Setting

The Western Australian Pregnancy Cohort (Raine) Study, Perth, Western Australia.

Subjects

Eight hundred and thirty-six males and females aged between 13 and 15 years.

Results

Mean mental health score as assessed by the CBCL was 45·24 (sd11·29). A high-quality breakfast consisting of at least three food groups was consumed by 11 % of adolescents, while 7 % of adolescents did not consume any items from core food groups on average over the 3 d period. The two most common core food groups consumed at breakfast in this population were dairy products followed by breads and cereals. For every additional food group eaten at breakfast, the associated total mental health score decreased by 1·66 (95 % CI −2·74, −0·59) after adjustment for potential confounding factors, representing an improvement in mental health score.

Conclusion

These findings support the concept that breakfast quality is an important component in the complex interaction between lifestyle factors and mental health in early adolescence.
A multilevel analysis of diet and socio-economic status in Scotland: investigating the ‘Glasgow effect’
Authors: Gray Linsay , Leyland Alastair H
Published: November 2008

Objective

To investigate differences between dietary habits in Glasgow and those in the rest of Scotland and the role that socio-economic factors have in explaining these.

Design

Data on age, sex, area deprivation, social class, educational qualifications, economic activity, health board region, postcode sector area and informants’ usual intake of foods covering sugary foods, snacks, fibre, starch, meat, fish, spreading fats, dairy products, salt, dietary supplements, fruit and vegetables were available from the 1995, 1998 and 2003 Scottish Health Surveys. Multilevel logistic regression was used to model the relationship between diet and living in Greater Glasgow compared with elsewhere in Scotland, unadjusted and adjusted for age, survey year and socio-economic factors, accounting for the clustering within postcode sector area.

Setting

Scotland.

Subjects

Subjects comprised 11 075 male and 14 052 female respondents.

Results

Lower consumption of high-fibre bread and potatoes/pasta/rice (among men and women), of cakes (men) and of cereals, meat, skimmed/semi-skimmed milk and green vegetables (women) in Glasgow was explained by socio-economic factors, as was higher consumption of non-diet soft drinks among women; lower consumption of ice cream, bread, cereals, meat and green vegetables (men) and high butter and salt consumption (women) in Greater Glasgow were not.

Conclusion

Associations between unhealthy eating and deprivation accounted for much of the tendency of people in Glasgow to have poor diets. Policies are needed to encourage improvements in diet in Glasgow and more effort is required to reduce social inequalities in eating habits. Glasgow’s poor diet will remain unless problems associated with poverty are tackled.
The Gender Gap in Self-Perceived Understanding of Politics in Canada and the United States
Authors: Gidengil Elisabeth , Giles Janine , Thomas Melanee
Published: November 2008

Despite the gains women have made since the advent of second-wave feminism, women remain less confident than men of their ability to understand politics. This gender gap has remained unchanged for decades, yet it has attracted surprisingly little scholarly attention in recent years. This article uses data from the 2000 American and 2004 Canadian election studies to assess whether differences in women's and men's socioeconomic resources help to explain the gender gap. We also examine whether there are differences in the ways that socioeconomic resources affect women's and men's self-perceived ability to understand politics. We focus particular attention on the effects of parenthood on women's confidence in their understanding of politics. Finally, we consider the role of feminism and gender role conceptions.
Gender Backlash in American Politics?
Authors: Sanbonmatsu Kira
Published: November 2008

In this essay, I start to sketch a research agenda about an electoral backlash against women's descriptive representation. Few scholars have considered the possibility of such a backlash. By “backlash,” I mean resistance to attempts to change the status quo. As Jane Mansbridge and Shauna Shames argue in this issue, when actors disadvantaged by the status quo work to enact change, they may be met by a reaction by those seeking to maintain existing power arrangements. In the following pages, I introduce the idea of a backlash against women's representation, propose several preliminary hypotheses about a backlash, and discuss ways of testing them.
Gender Politics and Gender Backlash in Zimbabwe
Authors: Ranchod-Nilsson Sita
Published: November 2008

In sub-Saharan Africa, the history of women's involvement in liberation struggles and the realignment of gender relations following independence have long been characterized as a kind of gender backlash. Whether national independence from colonial or settler rule was achieved in connection with nationalist movements or armed struggles, the scenarios of gender relations are remarkably similar. Particular groups of women are mobilized during the struggle for national liberation, their issues become part of the liberation movements' agendas, but following the achievement of independence, these same women are rapidly demobilized and the issues they raised during the national liberation struggle get marginalized amid competing and “more urgent” state priorities. Scholars have illuminated the historical and cultural specificities of this pattern in particular cases (Geiger 1997; Kruks, Rapp, and Young 1989; Seidman 1984 and 1999; Tétreault 1992; Urdang 1989). While this pattern fits with colloquial understandings of backlash, identifying the pattern does little to shed light on how state power gets infused with gender meaning in postindependence politics or how these power dynamics evolve.
TransCom model simulations of hourly atmospheric CO2: Analysis of synoptic‐scale variations for the period 2002–2003
Authors: Patra P. K. , Law R. M. , Peters W. , Rödenbeck C. , Takigawa M. , Aulagnier C. , Baker I. , Bergmann D. J. , Bousquet P. , Brandt J. , Bruhwiler L. , Cameron‐Smith P. J. , Christensen J. H. , Delage F. , Denning A. S. , Fan S. , Geels C. , Houweling S. , Imasu R. , Karstens U. , Kawa S. R. , Kleist J. , Krol M. C. , Lin S.‐J. , Lokupitiya R. , Maki T. , Maksyutov S. , Niwa Y. , Onishi R. , Parazoo N. , Pieterse G. , Rivier L. , Satoh M. , Serrar S. , Taguchi S. , Vautard R. , Vermeulen A. T. , Zhu Z.
Published: November 2008

The ability to reliably estimate CO2 fluxes from current in situ atmospheric CO2 measurements and future satellite CO2 measurements is dependent on transport model performance at synoptic and shorter timescales. The TransCom continuous experiment was designed to evaluate the performance of forward transport model simulations at hourly, daily, and synoptic timescales, and we focus on the latter two in this paper. Twenty‐five transport models or model variants submitted hourly time series of nine predetermined tracers (seven for CO2) at 280 locations. We extracted synoptic‐scale variability from daily averaged CO2 time series using a digital filter and analyzed the results by comparing them to atmospheric measurements at 35 locations. The correlations between modeled and observed synoptic CO2 variabilities were almost always largest with zero time lag and statistically significant for most models and most locations. Generally, the model results using diurnally varying land fluxes were closer to the observations compared to those obtained using monthly mean or daily average fluxes, and winter was often better simulated than summer. Model results at higher spatial resolution compared better with observations, mostly because these models were able to sample closer to the measurement site location. The amplitude and correlation of model‐data variability is strongly model and season dependent. Overall similarity in modeled synoptic CO2 variability suggests that the first‐order transport mechanisms are fairly well parameterized in the models, and no clear distinction was found between the meteorological analyses in capturing the synoptic‐scale dynamics.
Application of polarization and angular dependent artificial ground planes in compact planar high‐gain antenna design
Authors: Foroozesh A. , Shafai L. , Ng Mou Kehn M.
Published: November 2008

An artificial surface demonstrating angular and polarization dependency to the polarization of the applied field is introduced. This artificial surface consists of a periodic strip grating on a grounded dielectric slab. A method based on Floquet's modal expansion is presented to solve the scattering problem of such surfaces. A code based on method of moments (MoM) is also developed to analyze and design these artificial surfaces. The obtained results using these methods are compared against each other. The extracted reflection parameters are then employed to characterize the surface impedance of the artificial surface for different incident angles and both TE and TM polarizations. This artificial surface is used as the ground plane of cavity resonance antennas. Next, a highly reflective frequency selective surface (FSS) is designed to show high reflectivity at two different frequencies. This FSS is to be used as the superstrate layer of the cavity resonance antenna. The impedance surface of the artificial ground plane and the equivalent admittance of the designed FSS are employed in the transverse equivalent network (TEN) model to obtain radiation properties of such antennas. Finally, compact high‐gain dual‐band dual‐orthogonally polarized antennas are designed based on the aforementioned analyses.
Aerosol optical depth variability over Arabian Sea during drought and normal years of Indian monsoon
Authors: Rahul P. R. C. , Salvekar P. S. , Devara P. C. S.
Published: November 2008

We investigated MODIS (MODerate Resolution Imaging Spectroradiometer) derived Aerosol Optical Depth AOD (at 550 nm) and its variability in the mid monsoon month of July, over the Arabian Sea (45°E–75°E; 10°N–27°N), for the years 2001–2004, encompassing 2 normal (2001, 2003) and 2 drought years (2002 and 2004). Over the Arabian Sea, positive AOD anomalies (+0.2 to +0.7) during the normal years and negative AOD anomalies (−0.2 to −0.6) during drought years were observed. Variability in the concurrent Outgoing Long wave Radiation (OLR) anomalies from NCEP/NCAR reanalysis, rainfall anomalies from Tropical Rainfall Measuring Mission (TRMM) and NCEP surface winds had been used to examine the observed AOD variability. It is found that the wind direction was responsible for the negative/positive AOD anomalies corroborating to the negative/positive rainfall anomalies and positive/negative OLR anomalies during the drought years and vise a versa for the normal years.
Insight into modification of North China Craton from seismological study in the Shandong Province
Authors: Zheng T. Y. , Zhao L. , Xu W. W. , Zhu R. X.
Published: November 2008

The study region is located in the southeast edge of the North China Craton (NCC), which is an Archean craton that underwent removal and modification of the lithospheric mantle during the Late Mesozoic–Cenozoic. Teleseismic data from the NCISP‐1 experiment were used to image the velocity structures in lithosphere and to investigate the upper mantle anisotropy. Seismological results revealed that the present lithosphere consists of two parts with different structural features throughout, including crustal fabric, lithospheric velocity stratification, and anisotropic patterns. The formation of the contrasting structure is attributable to one of two possibilities: the trans‐lithospheric Tanlu fault zone (TLFZ) operated as an asthenospheric upwelling channel and facilitated the NCC reactivation, or the TLFZ separates the study region into two lithospheric blocks, with the ancient lithospheric materials remaining within the rejuvenated lithospheric mantle. These two possibilities suggest that thermal/chemical erosion may have played critical roles in the NCC reactivation.
Lightning‐induced lower‐hybrid turbulence and trapped Extremely Low Frequency (ELF) electromagnetic waves observed in deep equatorial plasma density depletions during intense magnetic storms
Authors: Malingre M. , Berthelier J.‐J. , Pfaff R. , Jasperse J. , Parrot M.
Published: November 2008

During the early phase of the intense magnetic storm of 7–11 November 2004, the DEMETER satellite encountered large‐scale equatorial plasma density depletions with density decreases of two or three orders of magnitude. Wave measurements carried out inside these depletions show the occurrence of broadband and localized lower‐hybrid turbulence triggered by whistlers propagating from thunderstorm lightning occurring below the orbit path. High‐sample‐rate waveforms reveal that this lower‐hybrid turbulence can evolve into localized large‐amplitude quasi‐monochromatic wave packets similar to lower‐hybrid structures that were, up to now, only observed in the auroral regions, usually on high‐latitude magnetic field lines associated with discrete aurora. These equatorial structures have typical amplitudes of up to 20 mV/m and durations of ∼20–30 ms. Simultaneous thermal ion measurements show that these bursts are often correlated with small‐scale density depletions of 5–10%. Although the lower‐hybrid structures are less intense than those observed in the auroral zone and although their energy source is different, our observations lend support to the idea that the formation of lower‐hybrid structures is an universal mechanism operating in inhomogeneous magnetized space plasmas in the presence of VLF whistler mode turbulence. Besides the lower‐hybrid turbulence, another interesting feature is the occurrence of strong narrowband electromagnetic ELF emissions with amplitudes of a few millivolts per meter at frequencies below the proton gyrofrequency. They are continuously observed throughout the entire depletion. These emissions occur not only within the depletions but also, although less intense, outside of them over a large latitudinal range. They are tentatively identified as magnetospheric line radiations (MLRs) commonly observed during magnetically disturbed periods. Similar events were observed on 15 May 2005 and on 24 August 2005 during two other intense magnetic storms.
Episodic slow slip events and rate‐and‐state friction
Authors: Rubin Allan M.
Published: November 2008

There are several ways of generating episodic slow slip events in models of rate‐and‐state friction. Here I explore the possibility that they arise on velocity‐weakening faults whose length is “tuned” in some sense. Unlike spring‐block sliders, which have a unique critical stiffness for instability, elastically deformable faults have multiple length scales (stiffnesses) relevant to nucleation. Slow slip events occur when the fault is large enough to initiate an event but too small for that event to reach dynamic instability. The available window of lengths depends upon the effective fracture energy of the growing nucleation zone. For the “aging” evolution law this fracture energy increases rapidly with slip speed, and the range of permissible lengths increases nearly as b/(b − a), where a and b are the coefficients of the velocity and state dependence of the frictional strength. This range becomes very large for faults that are near velocity‐neutral (a ∼ b). However, existing lab data firmly favor the “slip” law as a predictor of nucleation style, and for this law the effective fracture energy increases much less rapidly with slip speed. The range of fault lengths capable of hosting slow slip events in this case seems too small to explain why they are common to so many subduction zones. Slow slip can be stabilized over an exceedingly large range of fault lengths if the fracture energy increases with slip speed much more rapidly than for the aging law. An appealing mechanism is inelastic dilation of the fault zone coupled with pore pressure reduction and diffusive recovery.
A model for flash weakening by asperity melting during high‐speed earthquake slip
Authors: Rempel A. W. , Weaver S. L.
Published: November 2008

Recent results from laboratory experiments on a broad range of mineral systems exhibit dramatic drops in the effective friction coefficient μ once the slip rate exceeds a critical level Vw, which is typically O(0.1) m/s. This “flash weakening” has been attributed to the effects of localized heating at highly stressed microscopic asperities. We extend previous phenomenological treatments to assess whether melting at asperity contacts can explain the observed changes in strength. Using physical parameters obtained from the literature on the phase behavior and mechanical properties of quartz, albite, dolomite, gabbro, Westerly granite, and serpentinite, the predictions of our simplified model are in reasonable agreement with available experimental data. We derive approximate analytical expressions that suggest that strength changes are insensitive to the melt viscosity under conditions that likely include those during earthquake slip along major fault systems. Instead, the primary controls on μ are the ratio of slip rate V to Vw and the Stefan number S, which is defined as the ratio of the latent heat of fusion to the sensible heat required to raise the temperature from ambient levels. The phase behavior during the short lifetimes and at the high confining pressures of asperity contacts is a significant source of uncertainty in the parameter choices, as are the presence and availability of water. Nevertheless, our results are encouraging for further efforts to incorporate the microphysics of fault zone processes into earthquake simulations.
Climatology of drizzle in marine boundary layer clouds based on 1 year of data from CloudSat and Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO)
Authors: Leon David C. , Wang Zhien , Liu Dong
Published: November 2008

A survey of the frequency and characteristics of precipitation from low clouds over the oceans based on data from CloudSat and CALIPSO from July 2006 through June 2007 is presented. The low‐cloud fraction, drizzle occurrence, and estimated cloud base precipitation rate are examined globally and for eight subtropical and midlatitude stratocumulus (Sc) regions. This analysis is restricted clouds below 4 km. Drizzle detection and characterization is further restricted to clouds with tops above 1 km altitude. The maximum radar reflectivity within an individual CloudSat profile (Zmax) is used to classify the profile as precipitating or nonprecipitating. The distribution of Zmax for all profiles is bimodal with peaks around −23 and −12 dBZ interpreted as originating from populations of nondrizzling and drizzling clouds, respectively. Profiles where Zmax exceeds −18 dBZ are classified as drizzling. Drizzle is detected for 19–34% of cloudy profiles in the subtropical Sc regions and 37–44% of profiles from the midlatitude Sc regions. The cloud base precipitation rate is estimated using the relation: Rcb = 2 · Zmax0.7. The lower quartile/median/upper quartile precipitation rates are 0.25/0.6/2.0 mm d−1 for the subtropical Sc regions and 0.28/0.7/2.3 mm d−1 for midlatitude regions. A consistent nighttime increase in low‐cloud fraction and drizzle occurrence is observed for the subtropical Sc regions. For clouds with reff > 17 μm the drizzle occurrence can be treated as a function of LWP alone and exceeds 50% (75%) for a LWP of 50 (110) g m−2. For reff < 17 the drizzle occurrence is strongly dependent on both LWP and reff.
Factors controlling temporal and spatial distribution of total mercury and methylmercury in hyporheic sediments of the Allequash Creek wetland, northern Wisconsin
Authors: Creswell Joel E. , Kerr Sara C. , Meyer Matthew H. , Babiarz Christopher L. , Shafer Martin M. , Armstrong David E. , Roden Eric E.
Published: November 2008

Hyporheic pore water samples were collected from two sites within the Allequash Creek wetland, in Vilas County, northern Wisconsin, from August 2003 to October 2004. Samples were collected simultaneously at the surface and at 2, 5, 7, 10, and 15 cm below the sediment‐water interface. Concentration ranges were 3.7 to 58 pM for inorganic mercury, <0.5 to 16 pM for methylmercury, 3.02 to 152 μM and 0.38 to 96.6 μM for oxidized and reduced iron, respectively, 1.28 to 48.2 μM and< 0.05 to 9.76 μM for oxidized and reduced sulfur, respectively, and 109 to 689 μM for dissolved organic carbon. These concentrations are typical of anoxic environments such as wetlands and lake sediments. These data were used to gain a better understanding of the processes controlling spatial and temporal variability of inorganic mercury and methylmercury. Findings show that conditions conducive to mercury methylation exist in the hyporheic zone, especially in late summer, when accumulation of reduced iron and sulfide are indicative of microbial iron and sulfate reduction. Methylmercury concentrations also peak in late summer, with the highest concentrations appearing 2 to 10 cm below the sediment‐water interface. While there is a general covariance of total mercury and methylmercury over the depth profile, poor correlation was observed over time, highlighting the dynamic nature of hyporheic zone conditions and suggesting changes in mercury speciation and partitioning.
Evaluation of river discharges monitored by a fixed side‐looking Doppler profiler
Authors: Le Coz J. , Pierrefeu G. , Paquier A.
Published: November 2008

Fixed side‐looking Doppler current profilers (H‐ADCP) recently emerged as an innovating technique for the continuous monitoring of river discharges. The discharge can be computed from the flow velocities measured by the H‐ADCP along a horizontal profile across the section. This paper reports a field assessment of the quality of velocities and discharges provided by a 3‐narrow‐beam Teledyne RD Instruments, Inc. (RDI) 300 kHz H‐ADCP installed at the Saint‐Georges gauging station (Saône river in Lyon, France). Reference velocity and discharge values were established from 18 conventional ADCP river gauging campaigns over an extended discharge range (100–1800 m3/s). The comparison with ADCP data revealed that H‐ADCP velocity measurements were reliable (deviations <5%) in a near‐field range only (60 m out of a 95 m total section width). In the far field (beyond 60 m), H‐ADCP velocity measurements showed negative bias of up to −50% 90 m from the instrument. For section‐averaged velocities lower than 0.4 m/s approximately, H‐ADCP velocity measurements were found to be significantly underestimated over the whole cross section. The performances of several strategies (index velocity method and velocity profile method) for computing discharge were tested, compared, and discussed. For the velocity profile method, several profile laws and far‐field extrapolation methods were implemented. Both methods gave acceptable discharge values (deviations <5% typically) excepted at low‐flow conditions. The reasons why H‐ADCP velocities were unacceptably biased low in the far field and for low flow conditions require further investigation in order to define correcting measures.
Efficient regioselective synthesis of 3′‐O‐crotonylfloxuridine catalysed byPseudomonas cepacialipase
Authors: Zhao Zhilei , Zong Minhua , Li Ning
Published: November 2008

Pseudomonas cepacialipase‐catalysed preferential acylation of the secondary hydroxy group of FUdR (floxuridine) with vinyl crotonate was carried out in spite of the presence of the primary hydroxy group, and 3′‐O‐crotonylfloxuridine was prepared successfully for the first time. The isomerization of the double bond of crotonate, which occurs in conventional organic synthesis, could be effectively avoided during the enzymatic acylation. The effects of some key factors such as reaction medium, initialaw(water activity), molar ratio of vinyl crotonate to FUdR, FUdR concentration and reaction temperature on the reaction were examined. Under the optimized reaction conditions, the initial reaction rate, substrate conversion and 3′‐regioselectivity of the reaction were as high as 24 mM/h, 98% and 85% respectively.
To Get Hold of the Wrong End of the Stick: Reasons for Poor Idiom Understanding in Children With Reading Comprehension Difficulties
Authors: Cain Kate , Towse Andrea S.
Published: November 2008

Purpose

The aim was to identify the source of idiom understanding difficulties in children with specific reading comprehension failure.

Method

Two groups (
n
s = 15) of 9- to 10-year-olds participated. One group had age-appropriate word reading and reading comprehension; the other group had age-appropriate word reading but poor reading comprehension. Each child completed an independent assessment of semantic analysis skills and 2 multiple-choice assessments of idiom comprehension. In 1 assessment, idiomatic phrases were embedded in supportive story contexts; in the other assessment, they were presented out of context. Performance on transparent idioms (which are amenable to interpretation by semantic analysis) and opaque idioms (which can only be interpreted by inference from context if the meaning is not known) was compared.

Results

The groups demonstrated comparable semantic analysis skills and understanding of transparent idioms. Children with poor comprehension were impaired in the use of supportive context to aid their understanding of the opaque idioms.

Conclusions

The study identifies poor inference from context as a source of the idiom understanding difficulties in children with poor reading comprehension; there was no evidence that poor semantic analysis skills contributed to their difficulties. Children with poor comprehension should be supported in the use of context to understand unfamiliar figurative language.
Synthesis and photoluminescence characteristics of color-tunable BaY2ZnO5:Eu3+ phosphors
Authors: Liang Chih-Hao , Chang Yee-Cheng , Chang Yee-Shin
Published: November 2008

Color-tunable phosphors of BaY2−xEuxZnO5 (x=0.001–0.9) were synthesized using a vibrating milled solid state reaction. The results indicate that the emission spectra of BaY2−xEuxZnO5 samples excited at 395 nm exhibit a series of shaped peaks assigned to the D50→F7J (J=0,1,2,3,4) transitions. Luminescence from the higher excited states, such as D51, D52, and D53, were also observed even though the Eu3+ concentration was up to x=0.2. The chromaticity coordinate of BaY2−xEuxZnO5 phosphors varies with the Eu3+-doped concentrations from blue, white, to red, and which may be potentially applicable as a white light emitting phosphor for ultraviolet light emitting diodes.
A survey of factors contributing to accurate theoretical predictions of atomization energies and molecular structures
Authors: Feller David , Peterson Kirk A. , Dixon David A.
Published: November 2008

High level electronic structure predictions of thermochemical properties and molecular structure are capable of accuracy rivaling the very best experimental measurements as a result of rapid advances in hardware, software, and methodology. Despite the progress, real world limitations require practical approaches designed for handling general chemical systems that rely on composite strategies in which a single, intractable calculation is replaced by a series of smaller calculations. As typically implemented, these approaches produce a final, or “best,” estimate that is constructed from one major component, fine-tuned by multiple corrections that are assumed to be additive. Though individually much smaller than the original, unmanageable computational problem, these corrections are nonetheless extremely costly. This study presents a survey of the widely varying magnitude of the most important components contributing to the atomization energies and structures of 106 small molecules. It combines large Gaussian basis sets and coupled cluster theory up to quadruple excitations for all systems. In selected cases, the effects of quintuple excitations and/or full configuration interaction were also considered. The availability of reliable experimental data for most of the molecules permits an expanded statistical analysis of the accuracy of the approach. In cases where reliable experimental information is currently unavailable, the present results are expected to provide some of the most accurate benchmark values available.
Elliptic aspects of statistical mechanics on spheres
Authors: Dowker J. S. , Kirsten Klaus
Published: November 2008

Our earlier results on the temperature inversion properties and the ellipticization of the finite temperature internal energy on odd spheres are extended to orbifold factors of odd spheres and then to other thermodynamic quantities, in particular, to the specific heat. The behavior under modular transformations is facilitated by the introduction of a modular covariant derivative and it is shown that the specific heat on any odd sphere can be expressed in terms of just three functions. It is also shown that the free energy on the circle can be written elliptically.
Ionization and fragmentation of isomeric van der Waals complexes embedded in helium nanodroplets
Authors: Lewis William K. , Lindsay C. Michael , Miller Roger E.
Published: November 2008

The ionization and charge transfer processes, which occur when a doped helium droplet undergoes electron impact, are studied for droplets doped with van der Waals complexes with various structures and electrostatic moments. The mass spectra of the two isomers of hydrogen cyanide complexed with either cyanoacetylene or acetylene in helium droplets were obtained using optically selected mass spectrometry, and show that the structure of the complex has a large effect on the fragmentation pattern. The resulting fragmentation pattern is consistent with an ionization process in which charge steering strongly influences the site of initial ionization. The observed dissociation products may also be subject to caging by the helium matrix.
Relaxations in Ba2BiSbO6 double complex perovskite ceramics
Authors: Castro Manoel Carvalho , Paschoal Carlos William de Araujo , Snyder Frank C. , Lufaso Michael W.
Published: November 2008

The electric properties of the complex double perovskite Ba2BiSbO6 have been investigated using impedance spectroscopy in the frequency range from 1 Hz up to 1 MHz and in the temperature range from room temperature up to 560 K. There are two contributions to the electrical properties due to the grain and grain boundary. The oxygen vacancies play an important role in the conductivity and strongly increase the dielectric constant at high temperatures. The analysis of the frequency dependence of the conductivity clearly shows the structural phase transition of this compound near 515 K.
Acoustic solitary waves in dusty and/or multi-ion plasmas with cold, adiabatic, and hot constituents
Authors: Verheest Frank , Hellberg Manfred A. , Kourakis Ioannis
Published: November 2008

Large nonlinear acoustic waves are discussed in a four-component plasma, made up of two superhot isothermal species, and two species with lower thermal velocities, being, respectively, adiabatic and cold. First a model is considered in which the isothermal species are electrons and ions, while the cooler species are positive and/or negative dust. Using a Sagdeev pseudopotential formalism, large dust-acoustic structures have been studied in a systematic way, to delimit the compositional parameter space in which they can be found, without restrictions on the charges and masses of the dust species and their charge signs. Solitary waves can only occur for nonlinear structure velocities smaller than the adiabatic dust thermal velocity, leading to a novel dust-acoustic-like mode based on the interplay between the two dust species. If the cold and adiabatic dust are oppositely charged, only solitary waves exist, having the polarity of the cold dust, their parameter range being limited by infinite compression of the cold dust. However, when the charges of the cold and adiabatic species have the same sign, solitary structures are limited for increasing Mach numbers successively by infinite cold dust compression, by encountering the adiabatic dust sonic point, and by the occurrence of double layers. The latter have, for smaller Mach numbers, the same polarity as the charged dust, but switch at the high Mach number end to the opposite polarity. Typical Sagdeev pseudopotentials and solitary wave profiles have been presented. Finally, the analysis has nowhere used the assumption that the dust would be much more massive than the ions and hence, one or both dust species can easily be replaced by positive and/or negative ions and the conclusions will apply to that plasma model equally well. This would cover a number of different scenarios, such as, for example, very hot electrons and ions, together with a mix of adiabatic ions and dust (of either polarity) or a very hot electron-positron mix, together with a two-ion mix or together with adiabatic ions and cold dust (both of either charge sign), to name but some of the possible plasma compositions.
Electrical transport and thermoelectric properties of double filled compounds Ca0.1CexCo4Sb12 at low temperatures
Authors: Li D. , Yang K. , Hng H. H. , Qin X. Y. , Ma J.
Published: November 2008

The electrical transport and thermoelectric properties of CoSb3 and double filled compounds Ca0.1CexCo4Sb12 (x=0.05, 0.1, and 0.15) were investigated in the temperature range from 5 to 300 K. The results indicated that double filling of Ca and Ce has a strong influence on the temperature dependence of the electrical resistivity. For samples CoSb3 and Ca0.1Ce0.05Co4Sb12, the relationship of ln ρ∝1/T existed only in the temperature regimes of 100–200 and 160–300 K, respectively, while Mott’s law ln ρ∝T−1/4 was obeyed at lower temperatures below 100 and 160 K for CoSb3 and Ca0.1Ce0.05Co4Sb12, respectively. The results suggested a localization of charge carriers. Moreover, a transition from the semiconducting state (i.e., dρ/dT<0) (x=0.05) to the metallic state (i.e., dρ/dT>0) (0.050.5) was observed to be smaller than that of CoSb3. However, the increase in carrier concentration did not affect the absolute Seebeck coefficient values. In fact, a large absolute Seebeck coefficient was maintained, which was likely due to the large effective mass arising from the filler atoms. Moreover, the low-temperature lattice thermal conductivity of Ca0.1CexCo4Sb12 was observed to decrease monotonously with increasing Ce content, which was attributed to the rattling motion of the Ca and Ce atoms in the Sb cages. As a result, the figure of merit, ZT, of heavily filled compounds Ca0.1CexCo4Sb12 (x=0.1 and 0.15) improved over the whole temperature range investigated. In particular, ZT of Ca0.1Ce0.15Co4Sb12 was tenfold larger than that of CoSb3 at 300 K. The current results showed that double filling Ca and Ce is an efficient way in improving the thermoelectric properties.
Imaging of charge trapping in distorted carbon nanotubes by x-ray excited scanning probe microscopy
Authors: Ishii Masashi , Hamilton Bruce , Poolton Nigel
Published: November 2008

We have observed the distribution of electron trapping centers on distorted carbon nanotubes (CNTs) by a unique x-ray analysis technique that has both elemental and spatial selectivities. This technique involves the use of scanning probe microscopy (SPM) under synchrotron radiation excitation of the inner shell of carbon. The probe detects the Coulomb force that results from the relaxation of an electron bound to a defect site into the core hole state created by x-ray photon absorption. This results in a change in charge state of the defect. At the spatial resolution provided by the SPM technique, we observed the electron trapping centers distributed on the compressed and torsionally distorted CNTs. This direct association of mechanical distortion with defect sites indicates a potential risk of deterioration of electric properties during the fabrication and processing of CNT networks.
A model for debris clouds produced by impact of hypervelocity projectiles on multiplate structures
Authors: Zhang Qingming , Long Renrong , Huang Fenglei , Chen Li , Fu Yuesheng
Published: November 2008

Hypervelocity impact of spherical and cylindrical projectiles on multipate shields at velocities between 4 and 6km∕s was investigated experimentally. A model was developed to describe the motion of the debris clouds generated. Good agreement was obtained between the experimental and simulation results. The model is capable of predicting damage induced by the impact and can be applied to the optimization and design of multiplate shields.
Geometric optimization of an active magnetic regenerative refrigerator via second-law analysis
Authors: Li Peng , Gong Maoqiong , Wu Jianfeng
Published: November 2008

Previous analyses [Z. Yan and J. Chen, J. Appl. Phys. 72, 1 (1992); J. Chen and Z. Yan, ibid., 84, 1791 (1998); Lin et al., Physica B 344, 147 (2004); Yang et al., ibid., 364, 33 (2005); Xia et al., ibid., 381, 246 (2006).] of irreversibilities in magnetic refrigerators overlooked several important losses that could be dominant in a real active magnetic regenerative refrigerator (AMRR). No quantitative expressions have been provided yet to estimate the corresponding entropy generations in real AMRRs. The important geometric parameters of AMRRs, such as the aspect ratio of the active magnetic regenerator and the refrigerant diameter, are still arbitrarily chosen. Expressions for calculating different types of entropy generations in the AMRR were derived and used to optimize the aspect ratio and the refrigerant diameter. An optimal coefficient of performance (15.54) was achieved at an aspect ratio of 6.39 and a refrigerant diameter of 1.1mm for our current system. Further study showed that the dissipative sources (e.g., the fluid friction and the unbalanced magnetic forces) in AMRRs, which were overlooked by previous investigations, could significantly contribute to entropy generations.
Very high-κ ZrO2 with La2O3 (LaGeOx) passivating interfacial layers on germanium substrates
Authors: Mavrou G. , Tsipas P. , Sotiropoulos A. , Galata S. , Panayiotatos Y. , Dimoulas A. , Marchiori C. , Fompeyrine J.
Published: November 2008

Thin La2O3 (LaGeOx) passivating layers combined with ZrO2 caps form a chemically stable bilayer gate stack on Ge with good electrical properties. The most important observation is that a higher-κ tetragonal zirconia phase coexists with the most commonly observed monoclinic, increasing the κ value of the oxide to about 32, thus benefiting the measured stack equivalent oxide thickness. This indicates that the ZrO2/La2O3 combination could be a promising candidate gate stack for Ge metal-oxide-semiconductor devices in terms of scalability.
Structure based statistical theory of intermittency
Authors: Kim Eun-jin , Anderson Johan
Published: November 2008

A general statistical theory of the intermittency in turbulence based on short-lived coherent structures (instantons) is presented. The probability density functions (PDFs) of the flux R are shown to have an exponential scaling P(R)∝exp(−cRs) in the tails, with the exponent s=(n+1)∕m. Here, n and m are the order of the highest nonlinear interaction term and moments for which the PDFs are computed, respectively; c is constant depending on spatial profile of the coherent structure. The results can have important implications for understanding the universality often observed in simulations and experiments.