bluuebunny/crossref_metadata_2025 huggingface dataset:
Selection Methodology for Passive, Active, and Hybrid Inflow Control Completions
Authors: Lauritzen Jon Eric , Shahreyar Noman , Jacob Suresh
Published: May 2011

Well completions with downhole inflow control technologies are used to defer and control water or gas breakthrough thereby maximizing recovery. Active and passive inflow control devices dominate this technology. The paper presents the performance of these technologies in different well conditions and provides recommendations on their selection.

Passive inflow control devices (ICDs), combined with compartmentalization of the wellbore, balance inflow along the wellbore by creating a desired pressure regulation and prevent high-permeability sections from dominating the inflow. ICDs delay water and gas breakthrough and extend well life.

Active inflow-control completions consist of well equipment with multiple downhole packers and valves that segment the wellbore into multiple sections. The valves can be operated during the life of the well to regulate or shut off inflow from the section(s) that experience water or gas breakthrough while producing the remaining sections. The active valves may range from conventional sliding side doors to intelligent completions with remotely operated downhole valves and sensors.

Hybrid Completions integrate active control features with passive device systems within a single wellbore to leverage the value for both technologies to enhance well performance.

Simple static wellbore analysis and advanced transient analysis coupling of reservoir simulators to wellbore models was performed to review the performance of different completion technologies. The simulations cover different completion options from a base design of screens in barefoot completions to more advanced passive, active, and Hybrid Completions. Different reservoir and well conditions were simulated to analyze the performance of the completion systems. The proposed methodology will help in selecting a fit-for-purpose completion design for the life of the well ensuring that the performance objectives will not only be achieved, but also that the completion type selected has not been " over-designed?? for its intended purpose.

INTRODUCTION

The completion design for a horizontal well begins with an inflow control requirement at the sandface. Typical reasons for inflow control are significant permeability contrasts, presence of lost circulation or fracture zones, high frictional losses, and thin oil columns bounded by water and gas zones with high coning tendency and/or significant viscosity/mobility variations along the zones. In newer, undeveloped reservoirs, the inflow control is selected by analytical, semi-analytical assessments or based on parametric sensitivity-based modeling. Alternatively, in developed fields, inflow control requirements are more accurately determined by field experience, from the historical performance of adjacent wells. Several papersi (Al-Khelaiwi et.al, 2010 and Birchenko et.al 2009) have presented methodologies for selecting inflow control technologies based on factors like bore hole size, production rates, number of zones etc.
DP Vessel Side Shell Mounted Disconnectable System for Deep Water Development
Authors: Latimar Ian , Robbie Brian , Al-Sharif Majid M.
Published: May 2011

It was determined at early stages of development plan of the Phoenix Field in 2200 fsw water depth in GOM that permanent mooring system capable of maintaining the ship shape Floating Offshore Installation (FOI) on station under hurricane conditions would have cost far in excess of the allocated budget. It was therefore decided to adopt Dynamic Positioning as means for keeping the vessel at location and the use of a Disconnectable Transfer System (DTS) to tie production to the vessel and allow it to leave to a protected area at a certain threshold storm condition. Another factor which was considered to be an advantage by having a DTS is the fact that it allows the vessel to easily leave location and sail away to operate at a different location or to a shipyard for dry dock if required.

In order to minimize impact on ongoing vessel conversion; a side shell mounted DTS was selected as way forward. A portion of the vessel portside side shell at selected location was reinforced to handle anticipated loads from the external moonpool structure. A support structure was attached to the reinforced side shell. A moonpool was welded to the support structure with an inspection platform welded on top of it. This structural frame work provided the base to install a Swivel Stack, Hydraulic Power units, Pull-in Winches, Turntable and a Quick Connect Dis-Connect (QCDC) system. A buoy supporting all risers, umbilicals, mooring lines and clump weight; is parked in the moonpool at the connected state. When the buoy is disconnected, it is maintained at a submerged depth in the sea via a clump weight attached to the buoy. The depth is sufficient to minimize and/or eliminate impact due environmental conditions or external causes.

This paper will present the distinctive aspects of the DTS components facilities and structural design. It will also provide an overview of the key issues involved in designing, building and integrating a disconnectable system.

Introduction

The purpose of a DTS is to enable the Helix Producer 1 (HP1) FOI to disconnect from the field in severe weather conditions allowing the vessel to seek shelter. In addition it supports the transfer of fluids, power and controls between stationary and rotating sections of the FOI unit. This transfer must occur continuously and in a safe, leak-free manner where the swivels are one of the most critical elements onboard the vessel. The swivels will allow the produced and exported gas and oil together with electrical and hydraulic utilities to be transferred safely from the rotating FOI to the geo-stationary equipment under any defined environmental conditions in the field. The DTS includes a QCDC package to disconnect the vessel in severe weather. An active drive on the DTS keeps the buoy geostationary as the FOI weathervanes. Exported oil, gas, produced fluids and utilities transferred from the seabed through flexible risers & and the umbilical to the FOI.
Measurement from sun-synchronous orbit of a reaction rate controlling the diurnal NOx cycle in the stratosphere
Authors: Walker J. C. , Dudhia A.
Published: May 2011

Abstract. A reaction rate associated with the nighttime formation of an important diurnally varying species, N2O5, is determined from MIPAS-ENVISAT. During the day, photolysis of N2O5 in the stratosphere contributes to nitrogen-catalysed ozone destruction. However, at night concentrations of N2O5 increase, temporarily sequestering reactive NOx NO and NO2 in a natural cycle which regulates the majority of stratospheric ozone. In this paper, the reaction rate controlling the formation of N2O5 is determined from this instrument for the first time. The observed reaction rate is compared to the currently accepted rate determined from laboratory measurements. Good agreement is obtained between the observed and accepted experimental reaction rates within the error bars.
Cirrus cloud-temperature interactions in the tropical tropopause layer: a case study
Authors: Taylor J. R. , Randel W. , Jensen E. J.
Published: May 2011

Abstract. Thin cirrus clouds in the Tropical Tropopause Layer (TTL) have important ramifications for radiative transfer, stratospheric humidity, and vertical transport. A horizontally extensive and vertically thin cirrus cloud in the TTL was detected by the Cloud Aerosol LIDAR and Infrared Pathfinder Satellite Observations (CALIPSO) on 27–29 January, 2009 in the Tropical Eastern Pacific region, distant from any regions of deep convection. These observations indicate that the cloud is close to 3000 km in length along the CALIPSO orbit track. Measurements over this three day period indicate that the cloud event extended over a region from approximately 15° S to 10° N and 90° W to 150° W and may be one of the most extensive cirrus events ever observed. Coincident temperature observations from the Constellation of Observing Satellites for Meteorology, Ionosphere, and Climate (COSMIC) suggest that the cloud formed in-situ as a result of a cold anomaly arising from a midlatitude intrusion. The event appears to last for up to 2 days and the temperature observations do not show any indication of the expected infrared heating. It is hypothesized that the cloud could be maintained by either nucleation of numerous small ice crystals that do not sediment or by multiple localized ice nucleation events driven by temperature variability at scales smaller than the overall cloud field, producing small ice-crystal sizes which have sufficiently long residence times (≈53 h) to maintain the cloud. It is possible that the residence times are augmented by vertical motion which could also act to offset the expected infrared heating. Further observations of similar events will be required in order to conclusively explain this curious cloud.
Development of a high spectral resolution surface albedo product for the ARM Southern Great Plains central facility
Authors: McFarlane S. A. , Gaustad K. L. , Mlawer E. J. , Long C. N. , Delamere J.
Published: May 2011

Abstract. We present a method for identifying dominant surface type and estimating high spectral resolution surface albedo at the Atmospheric Radiation Measurement (ARM) facility at the Southern Great Plains (SGP) site in Oklahoma for use in radiative transfer calculations. Given a set of 6-channel narrowband visible and near-infrared irradiance measurements from upward and downward looking multi-filter radiometers (MFRs), four different surface types (snow-covered, green vegetation, partial vegetation, non-vegetated) can be identified. A normalized difference vegetation index (NDVI) is used to distinguish between vegetated and non-vegetated surfaces, and a scaled NDVI index is used to estimate the percentage of green vegetation in partially vegetated surfaces. Based on libraries of spectral albedo measurements, a piecewise continuous function is developed to estimate the high spectral resolution surface albedo for each surface type given the MFR albedo values as input. For partially vegetated surfaces, the albedo is estimated as a linear combination of the green vegetation and non-vegetated surface albedo values. The estimated albedo values are evaluated through comparison to high spectral resolution albedo measurements taken during several Intensive Observational Periods (IOPs) and through comparison of the integrated spectral albedo values to observed broadband albedo measurements. The estimated spectral albedo values agree well with observations for the visible wavelengths constrained by the MFR measurements, but have larger biases and variability at longer wavelengths. Additional MFR channels at 1100 nm and/or 1600 nm would help constrain the high resolution spectral albedo in the near infrared region.
Statistical analysis of monochromatic whistler waves near the Moon detected by Kaguya
Authors: Tsugawa Y. , Terada N. , Katoh Y. , Ono T. , Tsunakawa H. , Takahashi F. , Shibuya H. , Shimizu H. , Matsushima M.
Published: May 2011

Abstract. Observations are presented of monochromatic whistler waves near the Moon detected by the Lunar Magnetometer (LMAG) on board Kaguya. The waves were observed as narrowband magnetic fluctuations with frequencies close to 1 Hz, and were mostly left-hand polarized in the spacecraft frame. We performed a statistical analysis of the waves to identify the distributions of their intensity and occurrence. The results indicate that the waves were generated by the solar wind interaction with lunar crustal magnetic anomalies. The conditions for observation of the waves strongly depend on the solar zenith angle (SZA), and a high occurrence rate is recognized in the region of SZA between 40° to 90° with remarkable north-south and dawn-dusk asymmetries. We suggest that ion beams reflected by the lunar magnetic anomalies are a possible source of the waves.
The role of endophytic methane-oxidizing bacteria in submerged Sphagnum in determining methane emissions of Northeastern Siberian tundra
Authors: Parmentier F. J. W. , van Huissteden J. , Kip N. , Op den Camp H. J. M. , Jetten M. S. M. , Maximov T. C. , Dolman A. J.
Published: May 2011

Abstract. The role of the microbial processes governing methane emissions from tundra ecosystems is receiving increasing attention. Recently, cooperation between methanotrophic bacteria and submerged Sphagnum was shown to reduce methane emissions but also to supply CO2 for photosynthesis for the plant. Although this process was shown to be important in the laboratory, the differences that exist in methane emissions from inundated vegetation types with or without Sphagnum in the field have not been linked to these bacteria before. In this study, chamber flux measurements, an incubation study and a process model were used to investigate the drivers and controls on the relative difference in methane emissions between a submerged Sphagnum/sedge vegetation type and an inundated sedge vegetation type without Sphagnum. It was found that methane emissions in the Sphagnum-dominated vegetation type were 50 % lower than in the vegetation type without Sphagnum. A model sensitivity analysis showed that these differences could not sufficiently be explained by differences in methane production and plant transport. The model, combined with an incubation study, indicated that methane oxidation by endophytic bacteria, living in cooperation with submerged Sphagnum, plays a significant role in methane cycling at this site. This result is important for spatial upscaling as oxidation by these bacteria is likely involved in 15 % of the net methane emissions at this tundra site. Our findings support the notion that methane-oxidizing bacteria are an important factor in understanding the processes behind methane emissions in tundra.
Late Pliocene age control and composite depths at ODP Site 982, revisited
Authors: Khélifi N. , Sarnthein M. , Naafs B. D. A.
Published: May 2011

Abstract. Ocean Drilling Program (ODP) Site 982 provided a key sediment section at Rockall Plateau for reconstructing northeast Atlantic paleoceanography and monitoring benthic δ18O stratigraphy over the Late Pliocene to Quaternary onset of major Northern Hemisphere Glaciation. A renewed hole-specific inspection of magnetostratigraphic events and the addition of epibenthic δ18O records for short Pliocene sections in holes 982A, B, and C, crossing core breaks in the δ18O record published for Hole 982B, now imply a major revision of composite core depths. After tuning to the orbitally tuned reference record LR04 the new composite δ18O record results in a hiatus, where the Kaena magnetic event might been lost, and in a significant age reduction for all proxy records by 130 to 20 ka over the time span 3.2–2.7 million yr ago (Ma). Our study demonstrates the significance of reliable composite-depth scales and δ18O stratigraphies in ODP sediment records for ocean-wide correlations in paleoceanography and makes Late Pliocene trends found at Site 982 much better comparable to those published from elsewhere in the North Atlantic.
N‐Doped Polypyrrole‐Based Porous Carbons for CO2 Capture
Authors: Sevilla Marta , Valle‐Vigón Patricia , Fuertes Antonio B.
Published: May 2011

Highly porous N‐doped carbons have been successfully prepared by using KOH as activating agent and polypyrrole (PPy) as carbon precursor. These materials were investigated as sorbents for CO2 capture. The activation process was carried out under severe (KOH/PPy = 4) or mild (KOH/PPy = 2) activation conditions at different temperatures in the 600–800 °C range. Mildly activated carbons have two important characteristics: i) they contain a large number of nitrogen functional groups (up to 10.1 wt% N) identified as pyridonic‐N with a small proportion of pyridinic‐N groups, and ii) they exhibit, in relation to the carbons prepared with KOH/PPy = 4, narrower micropore sizes. The combination of both of these properties explains the large CO2 adsorption capacities of mildly activated carbon. In particular, a very high CO2 adsorption uptake of 6.2 mmol·g−1 (0 °C) was achieved for porous carbons prepared with KOH/PPy = 2 and 600 °C (1700 m2·g−1, pore size ≈ 1 nm and 10.1 wt% N). Furthermore, we observed that these porous carbons exhibit high CO2 adsorption rates, a good selectivity for CO2‐N2 separation and it can be easily regenerated.
Distributed computing approaches for large‐scale probit‐based stochastic user equilibrium problems
Authors: Liu Zhiyuan , Meng Qiang
Published: May 2011

Applications of probit‐based stochastic user equilibrium (SUE) principle on large‐scale networks have been largely limited because of the overwhelming computational burden in solving its stochastic network loading problem. A two‐stage Monte Carlo simulation method is recognized to have satisfactory accuracy level when solving this stochastic network loading. This paper thus works on the acceleration of the Monte Carlo simulation method via using distributed computing system. Three distributed computing approaches are then adopted on the workload partition of the Monte Carlo simulation method. Wherein, the first approach allocates each processor in the distributed computing system to solve each trial of the simulation in parallel and in turns, and the second approach assigns all the processors to solve the shortest‐path problems in one trial of the Monte Carlo simulation concurrently. The third approach is a combination of the first two, wherein both different trials of the Monte Carlo simulation as well as the shortest path problems in one trial are solved simultaneously. Performances of the three approaches are comprehensively tested by the Sioux‐Falls network and then a randomly generated network example. It shows that computational time for the probit‐based SUE problem can be largely reduced by any of these three approaches, and the first approach is found out to be superior to the other two. The first approach is then selected to calculate the probit‐based SUE problem on a large‐scale network example. Copyright © 2011 John Wiley & Sons, Ltd.
Mechanistic Insights on the Ruthenium‐Catalyzed Hydrogenation of Amides – C–N vs. C–O Cleavage
Authors: Cantillo David
Published: May 2011

Ruthenium‐catalyzed amide hydrogenation was thoroughly explored by means of DFT calculations. All the plausible pathways, including those involving the amide or imine tautomer, were assessed. The classical C–O cleavage and the recently reported C–N cleavage were compared by employing a bipyridyl‐based RuII pincer complex as catalyst in the calculations. The study reveals that C–O cleavage can be achieved directly over the amide substrate or its imine tautomer, since the computed pathways show analogous energy barriers. In addition, the mechanism for the novel C–N cleavage was elucidated by modeling all the reasonable intermediates and transition structures. The computed energy barrier is lower than that for C–O cleavage by more than 10 kcal mol–1, thus explaining the observed selectivity. The key role of the aromatization/dearomatization processes during the transformation is also disclosed.
Acute administration of toluene affects memory retention in novel object recognition test and memory function‐related gene expression in mice
Authors: Win‐Shwe Tin‐Tin , Fujimaki Hidekazu
Published: May 2011

The present study was designed to investigate the acute effect of a single administration of toluene (300 mg kg−1, i.p.) on memory retention in the hippocampus‐dependent novel object recognition test and N‐methyl‐D‐aspartate (NMDA) receptor subunit expression in the hippocampus of C3H/HeN female mice using real‐time RT‐PCR. We performed a novel object recognition test including a habituation phase, training phase and test phase in each mouse. Twenty‐four hours after the training phase, to determine the effect of acute toluene administration on memory retention, half of the mice (n = 10) were injected with toluene 60 min before the test phase. Toluene‐injected mice did not prefer novel objects and showed poor discrimination between novel and familiar objects and decreased expression of NMDA receptor subunit NR2B mRNA in the hippocampus. This is the first study to show that acute toluene injection impairs hippocampus‐dependent nonspatial memory retention accompanied by selective modulation of NMDA receptor subunit expression. Copyright © 2011 John Wiley & Sons, Ltd.
PIK3CA mutation is an early event in the development of endometriosis‐associated ovarian clear cell adenocarcinoma
Authors: Yamamoto Sohei , Tsuda Hitoshi , Takano Masashi , Iwaya Keichi , Tamai Seiichi , Matsubara Osamu
Published: May 2011

Clear cell adenocarcinoma (CCA), a highly lethal histological subtype of ovarian carcinoma, is a type of human cancer with a high frequency of activating mutations in the PIK3CA gene. In this study, we aimed to determine how these mutations contribute to tumour development of CCAs. Exons 9 and 20 of the PIK3CA gene were analysed by direct genomic DNA sequencing of 23 CCAs with synchronous putative precursor lesions (ie endometriosis adjacent to carcinoma, with or without cytological atypia) and their mutational statuses were compared. Somatic mutations of the PIK3CA gene were detected in 10/23 (43%) carcinomas and in all cases the type of mutation was H1047R in the kinase domain. The identical H1047R mutation was also detected in the coexisting endometriotic epithelium, adjacent to the CCAs, in nine of ten (90%) cases. Moreover, in six of the nine lesions, the H1047R mutation was identified even in the endometrioses lacking cytological atypia. These findings provide evidence that mutations of the PIK3CA gene occur in the putative precursor lesions of CCA, strongly suggesting that they are very early events in tumourigenesis, probably initiating the malignant transformation of endometriosis. A specific kinase inhibitor to mutated PIK3CA may potentially be an effective therapeutic reagent against these carcinomas. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
A robust numerical method for the potential vorticity based control variable transform in variational data assimilation
Authors: Buckeridge S. , Cullen M.J.P. , Scheichl R. , Wlasak M.
Published: May 2011

The potential vorticity based control variable transformation for variational data assimilation, proposed in Cullen (2003), is a promising alternative to the currently more common vorticity based transformation. It leads to a better decorrelation of the control variables, but it involves solving a highly ill‐conditioned elliptic partial differential equation (PDE), with a constraint. This PDE has so far been impossible to solve to any reasonable accuracy for realistic grid resolutions in finite difference formulations. Following on from the work in Buckeridge and Scheichl (2010) we propose a numerical method for it based on a Krylov subspace method with a multigrid preconditioner. The problem of interest includes a constraint in the form of two‐dimensional elliptic solves embedded within the main three‐dimensional problem. Thus the discretised problem cannot be formulated as a simple linear equation system with a sparse system matrix (as usual in elliptic PDEs). Therefore, in order to precondition the system we apply the multigrid method in Buckeridge and Scheichl (2010) to a simplified form of the three‐dimensional operator (without the embedded two‐dimensional problems) leading to an asymptotically optimal convergence of the preconditioned Krylov subspace method. The solvers used at the Met Office typically take over 100 iterations to converge to a residual tolerance of 0.1 and fail to converge to a tolerance of 10−2. The method proposed in this paper, in contrast, can converge to a tolerance of 10−2 within 15 iterations on all typical grid resolutions used at the Met Office, and is convergent to a tolerance of 10−6. In addition, the method demonstrates almost optimal parallel scalability. Copyright © 2011 Royal Meteorological Society and British Crown Copyright, the Met Office
Highly‐Ordered, 3D Petal‐Like Array for Surface‐Enhanced Raman Scattering
Authors: Qian Chuang , Ni Chao , Yu Wenxuan , Wu Wengang , Mao Haiyang , Wang Yifei , Xu Jun
Published: May 2011

Despite the great potential of the application of surface‐enhanced Raman scattering (SERS), the difficulty in fabricating suitable SERS substrates is still a problem. Based on the self‐assembly of silica nanoparticles, a simple method is here proposed to fabricate a highly‐ordered, 3D, petal‐like arrayed structure (3D PLAS) that serves as a promising SERS substrate for both its high reproducibility and enormous SERS enhancement. Such a novel structure is easily achieved by anisotropically etching a self‐assembly bilayer of silica nanoparticles, followed by metal deposition. The SERS performance of the 3D PLAS and its relationship with the main parameters, including the etching time, the diameter of silica nanoparticles, and the deposited metal film, are characterized using 632.8 nm incident light. With Rhodamine 6G as a probe molecule, the spatially averaged SERS enhancement factor is on the order of 5 × 107 and the local enhancement factor is much higher, both of which can be improved further by optimizing the parameters.
Influence of a High Magnetic Field on the Solubility of Ferrite and the Amount of Pearlite
Authors: Song J. Y. , Zhao X. , Zhang Y. D. , Esling C. , Zuo L.
Published: May 2011

Through microstructural analysis of a high purity Fe‐0.027%C alloy after continuously cooling transformation under a magnetic field, it is found that the amount of pearlite of the alloy decreases with the increase of the strength of the magnetic field. Under a 12 Tesla magnetic field, no pearlite appears. The result indicates that the carbon solubility limit of ferrite is enlarged by the magnetic field.
Accuracy of point-of-care ultrasound for identifying fractures in patients with orthopaedic trauma presenting to emergency department of the All India Institute of Medical Sciences, level 1 trauma centre
Authors: Sinha Tej Prakash , Kumar Sudeep , Bhoi Sanjeev , Goswami Ankur , Bhasin Amit , Ramchandani Radhakrishna , Rodha Mahaveer Singh , Gulati Vinay
Published: May 2011

Background

Radiography is the standard observation tool for examining orthopaedic injuries. Point-of-care ultrasonography may thus be a faster, non-invasive alternative to effectively identify bone fractures in the emergency department (ED) setting. The study compares the diagnostic utilities of BUS and radiography for identifying long bone fractures.

Methods

Prospective observation study with convenience sampling was conducted in ED in patients above 5 years, with post-traumatic upper and lower limb injuries requiring standard radiological examination after informed consent. The BUS examinations were done by emergency physician (EP) who had a brief training session to detect fractures. For every subject, radiographs were taken and reviewed for the presence of fracture by blinded orthopaedic specialist. Statistical analysis was done by SPSS.

Results

One hundred and thirty-three patients were enrolled in the study. Only 42 had fracture, out of which 36 were picked up by BUS. The overall sensitivity of the BUS in detecting fracture was 85.7% with a confidence interval (CI) of 0.70–0.94 and specificity of 100% with a CI (0.95–1.00).The positive predictive value (PPV) of USG was 100% with a CI (0.86–1.00) and negative predictive value (NPV) of 93.8% with a CI (0.86–0.97). There were six additional fractures which were recognised on X-ray and were not picked up by ultrasound.

Conclusion

Point-of-care ultrasonography can be utilised by emergency physicians after brief training to accurately identify long bone fractures. It may gain a more prominent role in pregnant and paediatric population as well as in mass casualty scenarios.
Continuity of packing measure functions of self-similar iterated function systems
Authors: QIU HUA
Published: May 2011

In this paper, we focus on the packing measures of self-similar sets. Let K be a self-similar set whose Hausdorff dimension and packing dimension equal s. We state that if K satisfies the strong open set condition with an open set 𝒪, then for each open ball B(x,r)⊂𝒪 centred in K, where 𝒫s denotes the s-dimensional packing measure. We use this inequality to obtain some precise density theorems for the packing measures of self-similar sets. These theorems can be used to compute the exact value of the s-dimensional packing measure 𝒫s (K) of K. Moreover, by using the above results, we show the continuity of the packing measure function of the attractors on the space of self-similar iterated function systems satisfying the strong separation condition. This result gives a complete answer to a question posed by Olsen in [15].
Intergenerational relationships within families of HIV-infected adults under antiretroviral treatment in Northern Thailand
Authors: LELIÈVRE ÉVA , LE CŒUR SOPHIE
Published: May 2011

Thailand has been severely affected by AIDS/HIV. The epidemic has undermined the health of the population of working age, placing stress on intergenerational relations and threatening the social fabric. Older people in families affected by the disease, although not the main victims, have experienced major changes in relationships with their adult children and grandchildren. However, the availability of antiretrovirals has transformed HIV infection from a lethal to a chronic disease. Intergenerational relationships are analysed with data from a quantitative survey of HIV-infected adults currently receiving antiretroviral treatment in Northern Thailand. The introduction of antiretroviral treatment has eased the pressure on families. Where HIV-infected adults are more dependent on their older parents, it is because they are single and childless or single parents. While ageing parents remain a source of support for their adult children, the introduction of antiretroviral treatment has radically changed the prospects for HIV-infected adults and their regained health allows them to work, take care of their family and fulfil their filial duties as expected in Thai society. If Thailand's original aim in introducing health policies in this area was to curtail the HIV epidemic, its positive impact on intergenerational relations is an additional benefit.
Accuracy and correlates of visual and verbal instruments assessing maternal perceptions of children's weight status: the Healthy Growth Study
Authors: Moschonis George , Iatridi Vasiliki , Mavrogianni Christina , Siatitsa Paraskevi-Eirini , Kyriakou Aikaterini E , Dede Vasiliki , Skouli Georgia , Sakellaropoulou Afroditi , Manios Yannis
Published: May 2011

Objective

To examine the accuracy of maternal ability to classify their children's weight status correctly using a verbal and a visual classification instrument and to detect significant correlates of maternal misperceptions.

Design

Cross-sectional study.

Setting

Primary schools in four counties from north, west, central and south Greece.

Subjects

A representative sample of 1858 primary-school children aged 9–13 years was examined. Two different instruments to assess maternal perceptions of their children's weight status, i.e. a verbal and a visual one, were used.

Results

Verbal and visual maternal underestimation rates of children's weight status were 15·0 % and 41·3 %, respectively. The frequency of underestimation was much higher among overweight and obese children for both instruments. The highest underestimation rates of 87·9 % and 82·1 % in overweight and obese boys, respectively, were obtained with the visual instrument. Multiple logistic regression modelling revealed that the likelihood of both verbal and visual maternal underestimation of their children's weight status was significantly higher for overweight mothers and for those with a lower educational level. Furthermore, children's male gender and a nanny or someone other than the mother as the child's primary caregiver were found to increase the odds of visual and verbal maternal underestimation of children's weight status, respectively.

Conclusions

The present study showed that the verbal instrument used to assess maternal perceptions of their children's weight status was more accurate compared with the visual one. However, both instruments showed that a considerable number of overweight and obese boys had their weight status underestimated by their mothers. Educating mothers to classify their children's weight status correctly might be a key factor for the implementation of successful childhood obesity prevention initiatives.
The dilemma of healthy eating and environmental sustainability: the case of fish
Authors: Clonan Angie , Holdsworth Michelle , Swift Judy A , Leibovici Didier , Wilson Paul
Published: May 2011

Objective

Despite widespread concern over exploitation of the European Union's fish stocks, dietary guidelines in the UK continue to recommend two portions of fish per week. The present study sought to investigate whether health and/or sustainability are motivating factors when purchasing and consuming fish and whether there are sociodemographic trends.

Design

A structured, self-completion postal questionnaire exploring consumers’ attitudes towards purchasing fish, their dietary intake, stated purchasing behaviour and sociodemographic information.

Setting

Nottinghamshire, UK.

Subjects

Adults from 842 households randomly selected from the electoral register.

Results

Over half of the participants (57·0 %) were aware of the health benefits of fish consumption and reported health as a primary motivator for purchasing fish; however, only 26·8 % actively sought to purchase fish from a sustainable source (e.g. Marine Stewardship Council (MSC) certified fish). Only 30·6 % of participants met current dietary recommendations for fish intake. Older respondents (>60 years of age) were more likely to report purchasing fish for health reasons and to buy MSC fish. Participants were significantly less likely to report MSC purchases if they agreed with the statement ‘I am confused about which type of fish I should be eating to protect fish stocks’ (P< 0·001).

Conclusions

The number of consumers purchasing fish for health reasons was more than those seeking sustainably sourced fish; yet, they still failed to meet the recommended intake set by the Food Standards Agency. Dietary advice to the public to increase consumption of fish conflicts with the prevailing pressure on fish stocks. Clear advice should be communicated enabling consumers to meet nutritional needs while protecting fish stocks.
Collection of mutants for functional genomics in the legume Medicago truncatula
Authors: Calderini O. , Carelli M. , Panara F. , Biazzi E. , Scotti C. , Tava A. , Porceddu A. , Arcioni S.
Published: May 2011

We have established mutant collections of the model species Medicago truncatula according to current protocols. In particular, we used a transposon (Tnt1) tagging method and an ethyl methanesulfonate (EMS) mutagenesis approach (TILLING). The collections were subjected to both forward and reverse genetics screenings, and several mutants were isolated that affect plant traits (e.g. shoot, root developments, flower morphology, etc.) and also biosynthetic pathways of secondary compounds (saponins and tannins). Genes responsible for some of the mutations were cloned and further characterized.
A study of conceptual model uncertainty in large‐scale CO2 storage simulation
Authors: Li Shuiquan , Zhang Ye , Zhang Xu
Published: May 2011

In this study, multiscale permeability upscaling is combined with a sensitivity study of model boundary condition to identify an optimal heterogeneity resolution in developing a reservoir model to represent a deep saline aquifer in CO2 storage simulation. A three‐dimensional, fully heterogeneous reservoir model is built for a deep saline aquifer in western Wyoming, where each grid cell is identified by multiple material tags. On the basis of these tags, permeability upscaling is conducted to create three increasingly simpler site models, a facies model, a layered model, and a formation model. Accuracy of upscaling is evaluated first, before CO2 simulation is conducted in all models. Since at the injection site, uncertainty exists in the nature of the reservoir compartment, end‐member boundary conditions are evaluated, whereby brine production is introduced to control formation fluid pressure. The effect of conceptual model uncertainty on model prediction is then assessed for each boundary condition. Results suggest that for the spatial and temporal scales considered, without brine production, optimal complexity of the upscaled model depends on the prediction metric of interest; the facies model is the most accurate for capturing plume shape, fluid pressure, and CO2 mass profiles, while the formation model is adequate for pressure prediction. The layered model is not accurate for predicting most of the performance metrics. Moreover, boundary condition impacts fluid pressure and the amount of CO2 that can be injected. For the boundary conditions tested, brine production can modulate fluid pressure, affect the direction of mobile gas flow, and influence the accuracy of the upscaled models. In particular, the importance of detailed geologic resolution is weakened when viscous force is strengthened in relation to gravity force. When brine production is active, variability of the predictions by the upscaled models becomes smaller and the predictions are more accurate, suggesting a subtle but important interplay between heterogeneity resolution, fluid driving forces, and model predictions.
Effect of a metallic core on transient geomagnetic induction
Authors: Velímský J. , Finlay C. C.
Published: May 2011

Magnetic fields due to the magnetospheric ring current, together with their induced counterparts, must be correctly taken into account when modeling the geomagnetic field using modern observatory and satellite measurements. It is common practice to parameterize the induced field using a response function depending on a spherically symmetric electrical conductivity model of the solid Earth. Here we show that Earth's metallic core should be included in such conductivity models, which has not previously been the case. Abrupt changes in the amplitude of the ring current during geomagnetic storms excite a wide range of frequencies, some of which can induce electrical currents in the core. These currents decay very slowly because of the high conductivity of the core; the resulting induced field will therefore not be of zero mean even when averaged over many years. We present the results of time domain numerical simulations of induction that demonstrate the influence of a conducting core in an idealized experiment based on a synthetic geomagnetic storm. Moving to a more realistic scenario we show that taking 50 years of Dst(t) index as an input, an induced field Ist(t) with a mean value (when averaged over 10 years) of up to −1.5 nT is obtained. We conclude that transient induction in the metallic core caused by magnetospheric field variations must be included in accurate portrayals of the near‐Earth magnetic environment.
Some Serrin-type regularity criteria for weak solutions to the Navier-Stokes equations
Authors: Zhang Zujin , Yao Zheng-an , Lu Ming , Ni Lidiao
Published: May 2011

We consider the regularity criteria for a weak solution \documentclass[12pt]{minimal}\begin{document}$\bm {u}=(u_1,u_2,u_3)$\end{document}u=(u1,u2,u3) to the Navier-Stokes equations in \documentclass[12pt]{minimal}\begin{document}$\mathbb {R}^3$\end{document}R3. Denoting by \documentclass[12pt]{minimal}\begin{document}$\bm {\omega }=(\omega _1,\omega _2,\omega _3)=\mbox{curl }\bm {u}$\end{document}ω=(ω1,ω2,ω3)=curlu the vorticity, we then prove that \documentclass[12pt]{minimal}\begin{document}$\bm {u}$\end{document}u is smooth, provided u3, ω3; or ∂3u3, ω3 are in some Serrin-type integrability classes.
Coercivity change in an FePt thin layer in a Hall device by voltage application
Authors: Seki Takeshi , Kohda Makoto , Nitta Junsaku , Takanashi Koki
Published: May 2011

The coercivity (Hc) of a perpendicularly magnetized FePt layer was modulated by applying the voltage (Vapp) to a Hall device through MgO and Al–O insulating layers. A change in ∼40 Oe in Hc was observed by changing Vapp from −13 to 13 V. From the quantitative analysis of the voltage effect on Hc, the change in the anisotropy energy by voltage application was evaluated to be 18.6 fJ/V m, which was of the same order as the theoretical prediction. The role of the MgO layer for the voltage effect was also discussed.
Platelet gene therapy improves hemostatic function for integrin αIIbβ3-deficient dogs
Authors: Fang Juan , Jensen Eric S. , Boudreaux Mary K. , Du Lily M. , Hawkins Troy B. , Koukouritaki Sevasti B. , Cornetta Kenneth , Wilcox David A.
Published: May 2011

Activated blood platelets mediate the primary response to vascular injury. Although molecular abnormalities of platelet proteins occur infrequently, taken collectively, an inherited platelet defect accounts for a bleeding diathesis in ≈1:20,000 individuals. One rare example of a platelet disorder, Glanzmann thrombasthenia (GT), is characterized by life-long morbidity and mortality due to molecular abnormalities in a major platelet adhesion receptor, integrin αIIbβ3. Transfusion therapy is frequently inadequate because patients often generate antibodies to αIIbβ3, leading to immune-mediated destruction of healthy platelets. In the most severe cases allogeneic bone marrow transplantation has been used, yet because of the risk of the procedure it has been limited to few patients. Thus, hematopoietic stem cell gene transfer was explored as a strategy to improve platelet function within a canine model for GT. Bleeding complications necessitated the use of a mild pretransplant conditioning regimen; therefore, in vivo drug selection was used to improve engraftment of autologously transplanted cells. Approximately 5,000 αIIbβ3 receptors formed on 10% of platelets. These modest levels allowed platelets to adhere to αIIbβ3’s major ligand (fibrinogen), form aggregates, and mediate retraction of a fibrin clot. Remarkably, improved hemostatic function was evident, with ≤135-fold reduced blood loss, and improved buccal bleeding times decreased to 4 min for up to 5 y after transplant. One of four transplanted dogs developed a significant antibody response to αIIbβ3 that was attenuated effectively with transient immune suppression. These results indicate that gene therapy could become a practical approach for treating inherited platelet defects.
Reactive nanostructured membranes for water purification
Authors: Lewis Scott R. , Datta Saurav , Gui Minghui , Coker Eric L. , Huggins Frank E. , Daunert Sylvia , Bachas Leonidas , Bhattacharyya Dibakar
Published: May 2011

Many current treatments for the reclamation of contaminated water sources are chemical-intensive, energy-intensive, and/or require posttreatment due to unwanted by-product formation. We demonstrate that through the integration of nanostructured materials, enzymatic catalysis, and iron-catalyzed free radical reactions within pore-functionalized synthetic membrane platforms, we are able to conduct environmentally important oxidative reactions for toxic organic degradation and detoxification from water without the addition of expensive or harmful chemicals. In contrast to conventional, passive membrane technologies, our approach utilizes two independently controlled, nanostructured membranes in a stacked configuration for the generation of the necessary oxidants. These include biocatalytic and organic/inorganic (polymer/iron) nanocomposite membranes. The bioactive (top) membrane contains an electrostatically immobilized enzyme for the catalytic production of one of the main reactants, hydrogen peroxide (H
2
O
2
), from glucose. The bottom membrane contains either immobilized iron ions or ferrihydrite/iron oxide nanoparticles for the decomposition of hydrogen peroxide to form powerful free radical oxidants. By permeating (at low pressure) a solution containing a model organic contaminant, such as trichlorophenol, with glucose in oxygen-saturated water through the membrane stack, significant contaminant degradation was realized. To illustrate the effectiveness of this membrane platform in real-world applications, membrane-immobilized ferrihydrite/iron oxide nanoparticles were reacted with hydrogen peroxide to form free radicals for the degradation of a chlorinated organic contaminant in actual groundwater. Although we establish the development of these nanostructured materials for environmental applications, the practical and methodological advances demonstrated here permit the extension of their use to applications including disinfection and/or virus inactivation.
Community interactions govern host-switching with implications for host–parasite coevolutionary history
Authors: Harbison Christopher W. , Clayton Dale H.
Published: May 2011

Reciprocal selective effects between coevolving species are often influenced by interactions with the broader ecological community. Community-level interactions may also influence macroevolutionary patterns of coevolution, such as cospeciation, but this hypothesis has received little attention. We studied two groups of ecologically similar feather lice (Phthiraptera: Ischnocera) that differ in their patterns of association with a single group of hosts. The two groups, “body lice” and “wing lice,” are both parasites of pigeons and doves (Columbiformes). Body lice are more host-specific and show greater population genetic structure than wing lice. The macroevolutionary history of body lice also parallels that of their columbiform hosts more closely than does the evolutionary history of wing lice. The closer association of body lice with hosts, compared with wing lice, can be explained if body lice are less capable of switching hosts than wing lice. Wing lice sometimes disperse phoretically on parasitic flies (Diptera: Hippoboscidae), but body lice seldom engage in this behavior. We tested the hypothesis that wing lice switch host species more often than body lice, and that the difference is governed by phoresis. Our results show that, where flies are present, wing lice switch to novel host species in sufficient numbers to establish viable populations on the new host. Body lice do not switch hosts, even where flies are present. Thus, differences in the coevolutionary history of wing and body lice can be explained by differences in host-switching, mediated by a member of the broader parasite community.