bluuebunny/crossref_metadata_2025_split huggingface dataset:
EVALUATING SHALLOW‐WATER BATHYMETRY FROM THROUGH‐WATER TERRESTRIAL LASER SCANNING UNDER A RANGE OF HYDRAULIC AND PHYSICAL WATER QUALITY CONDITIONS
Authors: Smith M.W. , Vericat D. 
Published: July 2013

ABSTRACTThe fine‐scale structure of the water–sediment boundary in fluvial environments is dynamic and complex, influencing near‐bed flows, sediment transport and instream ecology. However, accurate high‐resolution surveying of marginally or partially inundated areas of river channels is problematic. Previous work has shown that terrestrial laser scanning (TLS) through relatively shallow‐water columns using standard green‐wavelength equipment introduces errors of <5 mm in a static, clear water column. This paper presents seven laboratory and field tests of through‐water TLS under variable flow velocities, depths, suspended sediment concentrations, water colour levels and scan ranges. Flow velocity decreased point accuracy only for supercritical flows, whereas point density decreased as a function of both water depth and suspended sediment concentration. A similar point return threshold was observed for water colour variations with no grains in suspension. Conversely, point precision and accuracy were a function of suspended sediment concentration alone (a threshold of 0.11 g L−1 was observed). Field tests showed larger errors (<10 mm) and lower point precisions. A clear‐water depth‐penetration limit of 0.68 m was identified. Fluvial bathymetry acquired from through‐water TLS is presented for a gravel/boulder bed reach. Despite observed limits, these experiments demonstrate that our approach provides centimetre‐resolution bathymetry and sub‐aerial survey in an integrated dataset without the need for the following: (i) additional financial resources; (ii) concurrent depth measurements; or (iii) extra field effort for bathymetry acquisition, thereby enabling regular surveys to characterize the fine‐scale structure of channel beds and to constrain the geomorphic effect of individual flood events. Copyright © 2013 John Wiley & Sons, Ltd.
Smartphone security: understanding smartphone users' trust in information security management
Authors: Jang Yu‐Teng , Chang Shuchih Ernest , Tsai Yi‐Jey 
Published: July 2013

ABSTRACTOwing to the rapid advancement of technologies, today's mobile phones (e.g., smartphones) can not only fulfill users' basic requirements for communication purposes but also serve as powerful pervasive devices with various valuable functions for users. With wide and close Internet accessibility, smartphones nowadays inevitably suffer security threats and information security management (ISM) issues like common computers do. In this research, information security related trust issues are investigated through a user‐based empirical study. Our research project aims to study the relationships between smartphone users' computer literacy, network literacy, knowledge on mobile phone viruses, and trust in ISM principles (i.e., confidentiality, integrity, and availability). The study results indicate that smartphone users' network literacy positively influence their knowledge on mobile phone viruses, whereas users' computer literacy is not significantly associated with their knowledge on mobile phone viruses. Moreover, smartphone users' knowledge on mobile phone viruses would significantly affect their trusts in three ISM principles. The validated research model and corresponding findings can be referenced by business executives and ISM decision makers in electronic commerce (e‐commerce) for making favorable tactics to catch the revolutionary benefits offered by effective ISM policies in the ubiquitous computing environment. Copyright © 2013 John Wiley & Sons, Ltd.
Multifunctional Upconversion Mesoporous Silica Nanostructures for Dual Modal Imaging and In Vivo Drug Delivery
Authors: Li Chunxia , Yang Dongmei , Ma Ping'an , Chen Yinyin , Wu Yuan , Hou Zhiyou , Dai Yunlu , Zhao Jihong , Sui Changping , Lin Jun 
Published: July 2013

AbstractIncorporating the agents for magnetic resonance imaging (MRI), optical imaging, and therapy in one nanostructured matrix to construct multifunctional nanomedical platform has attracted great attention for simultaneous diagnostic and therapeutic applications. In this work, a facile methodology is developed to construct a multifunctional anticancer drug nanocarrier by combining the special advantages of upconversion nanoparticles and mesoporous silica. β‐NaYF4:Yb3+, Er3+@β‐NaGdF4:Yb3+ is chosen as it can provide the dual modality of upconversion luminescence and MRI. Then mesoporous silica is directly coated onto the upconversion nanoparticles to form discrete, monodisperse, highly uniform, and core–shell structured nanospheres (labeled as UCNPs@mSiO2), which are subsequently functionalized with hydrophilic polymer poly(ethylene glycol) (PEG) to improve the colloidal stability and biocompatibility. The obtained multifunctional nanocomposites can be used as an anticancer drug delivery carrier and applied for imaging. The anticancer drug doxorubicin (DOX) is absorbed into UCNPs@mSiO2‐PEG nanospheres and released in a pH‐sensitive pattern. In vitro cell cytotoxicity tests on cancer cells verify that the DOX‐loaded UCNPs@mSiO2‐PEG has comparable cytotoxicity with free DOX at the same concentration of DOX. In addition, the T1‐weighted MRI that measures in aqueous solutions reveals that the contrast brightening increases with the concentration of Gd3+ component. Upconversion luminescence images of UCNPs@mSiO2‐PEG uptaken by cells show green emission under 980 nm infrared laser excitation. Finally, the nanocomposites show low systematic toxicity and high in vivo antitumor therapy efficacy. These findings highlight the fascinating features of upconversion‐mesoporous nanocomposites as multimodality imaging contrast agents and nanocarrier for drug molecules.
Brief report: miR-290–295 regulate embryonic stem cell differentiation propensities by repressing pax6
Authors: Kaspi Haggai , Chapnik Elik , Levy Maayan , Beck Gilad , Hornstein Eran , Soen Yoav 
Published: July 2013

Abstract
microRNAs of the miR-290–295 family are selectively expressed at high levels in mouse embryonic stem cells (mESCs) and have established roles in regulating self-renewal. However, the potential influence of these microRNAs on cell fate acquisition during differentiation has been overlooked. Here, we show that miR-290–295 regulate the propensity of mESCs to acquire specific fates. We generated a new miR-290–295-null mESC model, which exhibits increased propensity to generate ectoderm, at the expense of endoderm and mesoderm lineages. We further found that in wild-type cells, miR-290–295 repress Pax6 and ectoderm differentiation; accordingly, Pax6 knockdown partially rescues the mESCs differentiation impairment that is caused by loss of miR-290–295. Thus, in addition to regulating self-renewal, the large reservoir of miR-290–295 in undifferentiated mESCs fine-tunes the expression of master transcriptional factors, such as Pax6, thereby regulating the equilibrium of fate acquisition by mESC descendants.
Tuning of β-catenin activity is required to stabilize self-renewal of rat embryonic stem cells
Authors: Meek Stephen , Wei Jun , Sutherland Linda , Nilges Benedikt , Buehr Mia , Tomlinson Simon R. , Thomson Alison J. , Burdon Tom 
Published: July 2013

Abstract
Stabilization of β-catenin, through inhibition of glycogen synthase kinase 3 (GSK3) activity, in conjunction with inhibition of mitogen-activated protein kinase kinase 1/2 (MEK) promotes self-renewal of naïve-type mouse embryonic stem cells (ESC). In developmentally more advanced, primed-type, epiblast stem cells, however, β-catenin activity induces differentiation. We investigated the response of rat ESCs to β-catenin signaling and found that when maintained on feeder-support cells in the presence of a MEK inhibitor alone (1i culture), the derivation efficiency, growth, karyotypic stability, transcriptional profile, and differentiation potential of rat ESC cultures was similar to that of cell lines established using both MEK and GSK3 inhibitors (2i culture). Equivalent mouse ESCs, by comparison, differentiated in identical 1i conditions, consistent with insufficient β-catenin activity. This interspecies difference in reliance on GSK3 inhibition corresponded with higher overall levels of β-catenin activity in rat ESCs. Indeed, rat ESCs displayed widespread expression of the mesendoderm-associated β-catenin targets, Brachyury and Cdx2 in 2i medium, and overt differentiation upon further increases in β-catenin activity. In contrast, mouse ESCs were resistant to differentiation at similarly elevated doses of GSK3 inhibitor. Interestingly, without feeder support, moderate levels of GSK3 inhibition were necessary to support effective growth of rat ESC, confirming the conserved role for β-catenin in ESC self-renewal. This work identifies β-catenin signaling as a molecular rheostat in rat ESC, regulating self-renewal in a dose-dependent manner, and highlights the potential importance of controlling flux in this signaling pathway to achieve effective stabilization of naïve pluripotency.
Patterning pluripotency in embryonic stem cells
Authors: Zhang Yue Shelby , Sevilla Ana , Wan Leo Q. , Lemischka Ihor R. , Vunjak-Novakovic Gordana 
Published: July 2013

Abstract
Developmental gradients of morphogens and the formation of boundaries guide the choices between self-renewal and differentiation in stem cells. Still, surprisingly little is known about gene expression signatures of differentiating stem cells at the boundaries between regions. We thus combined inducible gene expression with a microfluidic technology to pattern gene expression in murine embryonic stem cells. Regional depletion of the Nanog transcriptional regulator was achieved through the exposure of cells to microfluidic gradients of morphogens. In this way, we established pluripotency-differentiation boundaries between Nanog expressing cells (pluripotency zone) and Nanog suppressed cells (early differentiation zone) within the same cell population, with a gradient of Nanog expression across the individual cell colonies, to serve as a mimic of the developmental process. Using this system, we identified strong interactions between Nanog and its target genes by constructing a network with Nanog as the root and the measured levels of gene expression in each region. Gene expression patterns at the pluripotency-differentiation boundaries recreated in vitro were similar to those in the developing blastocyst. This approach to the study of cellular commitment at the boundaries between gene expression domains, a phenomenon critical for understanding of early development, has potential to benefit fundamental research of stem cells and their application in regenerative medicine.
Space weather radiation effects on geostationary satellite solid‐state power amplifiers
Authors: Lohmeyer W.Q. , Cahoy K. 
Published: July 2013

AbstractIn order to understand and mitigate the effects of space weather on the performance of geostationary (GEO) communications satellites, we analyze 16 years of archived telemetry data from Inmarsat, the UK‐based telecommunications company. We compare 665,112 operational hours of housekeeping telemetry from two generations of satellites, designated as Fleet A and Fleet B. Each generation experienced 13 solid‐state power amplifier (SSPA) anomalies for a total of 26 anomalies from 1996 to 2012. We compare telemetry from the Inmarsat anomalies with space weather observations, including data from the OMNI2 database, Geostationary Operational Environmental Satellites, the Advanced Composition Explorer Satellite, and Los Alamos National Laboratory (LANL) GEO observations; the evolution of the sunspot number; and the Kp index. Most SSPA anomalies for Fleet A occur as solar activity declines; Fleet B has not yet experienced a full solar cycle. For both fleets, the average value of Kp remained < 2 over time periods of 2 days, 3 days, and 2 weeks around the time of anomaly, which suggests that the anomalies occurred at times of relatively quiet geomagnetic activity and that they were probably not solely caused by surface charging. From 1996 to 2009, the average of the 1.8–3.5 MeV electron flux was 1.98 #/(cm2 s st keV). Five of the 26 anomalies, unfortunately, do not have corresponding science observations (specifically, electron flux data in the LANL data set), so part of this study focuses on the 21 anomalies when science observations were available. Six out of 21 anomalies experienced a high‐energy electron flux greater than 1.5 standard deviations above the mean of the log10 of the flux between 7 and 14 days prior to the anomaly. By contrast, a Monte Carlo simulation finds that on average, only 2.8 out of 21 (13%) of randomly assigned “anomalies” occur between 7 and 14 days after an electron flux greater than 1.5 standard deviations above the mean. Our observations suggest that internal charging from either past elevated radiation belt fluxes or some conditions related to relativistic electron enhancements (either causally or accidentally) is most likely responsible for the SSPA anomalies. We next consider the timing of these anomalies with respect to the local time (LT) and season. Anomalies occur at all LT sectors with 46% (Fleet A) and 38.5% (Fleet B) in the midnight to dawn sector and 54% (Fleet A) and 46% (Fleet B) in the local noon to dusk sector. From the local time distribution, surface charging does not appear to be the sole causative agent of the anomalies. Understanding the connection between the space weather conditions and anomalies on subsystems and specific components on identical and similar geostationary communications satellites for periods of time longer than a solar cycle will help guide design improvements and provide insight on their operation during space weather events.
Property‐Model Methodology: A Model‐Based Systems Engineering Approach UsingVHDL‐AMS
Authors: Micouin Patrice 
Published: July 2013

ABSTRACTThe purpose of this paper is to contribute to the definition of a Model Based Systems Engineering (MBSE) approach which would meet the objective laid out byINCOSEin its Systems Engineering Vision 2020. After briefly presenting the tools used and summarizing a state‐of‐the‐art system design process, we show how it is possible to define property‐based requirements (PBRs) as features of specification models and to apply the design process to this specification model in order to develop design models. Then, we show how it is possible to perform a simulation‐based verification process of design models in order to detect and remove design errors, to substitute the initial requirements of the system with derived requirements gradually assigned to the subentities of the system, to perform a simulation‐based validation process of specification models in order to detect and remove specification errors. Additionally, we show how we define safetyPBRsto prevent the consequences of failure conditions and verify mitigation means, such as redundancy or dissimilarity, introduced in design models to meet these safetyPBRs. Thus, we consider that our proposals improveMBSEcurrent practices making them safer for the development of present and future systems.
A novel decoding scheme based on recalculation for double binary convolutional turbo code
Authors: Zhan Ming , Wu Jun , Zhou Liang 
Published: July 2013

AbstractTo decrease the storage complexity of a double binary convolutional turbo code (DB‐CTC) decoder, a novel decoding scheme is proposed in this paper. Different from the conventional decoding scheme, only a part of the state metrics is stored in the last‐in first‐out (LIFO) state metrics cache (SMC). Based on an improved maximum a posteriori probability (MAP) algorithm, we present a method to recalculate the unstored state metrics at the corresponding decoding time slot, and discuss in detail the procedures of the recalculation are discussed. Because of the compare–select–recalculate processing operations, compared to the classical decoding scheme, the proposed decoding scheme reduces the storage complexity of SMC and the amount of memory accesses by approximately 40% while limiting involved computational cost. Moreover, simulation results show that the proposed scheme achieves good decoding performance, which is close to that of the well‐known Log‐MAP algorithm. © 2013 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Different response to acetic acid stress in Saccharomyces cerevisiae wild‐type and l‐ascorbic acid‐producing strains
Authors: Martani Francesca , Fossati Tiziana , Posteri Riccardo , Signori Lorenzo , Porro Danilo , Branduardi Paola 
Published: July 2013

AbstractBiotechnological processes are of increasing significance for industrial production of fine and bulk chemicals, including biofuels. Unfortunately, under operative conditions microorganisms meet multiple stresses, such as non‐optimal pH, temperature, oxygenation and osmotic stress. Moreover, they have to face inhibitory compounds released during the pretreatment of lignocellulosic biomasses, which constitute the preferential substrate for second‐generation processes. Inhibitors include furan derivatives, phenolic compounds and weak organic acids, among which acetic acid is one of the most abundant and detrimental for cells. They impair cellular metabolism and growth, reducing the productivity of the process: therefore, the development of robust cell factories with improved production rates and resistance is of crucial importance. Here we show that a yeast strain engineered to endogenously produce vitamin C exhibits an increased tolerance compared to the parental strain when exposed to acetic acid at moderately toxic concentrations, measured as viability on plates. Starting from this evidence, we investigated more deeply: (a) the nature and levels of reactive oxygen species (ROS); (b) the activation of enzymes that act directly as detoxifiers of reactive oxygen species, such as superoxide dismutase (SOD) and catalase, in parental and engineered strains during acetic acid stress. The data indicate that the engineered strain can better recover from stress by limiting ROS accumulation, independently from SOD activation. The engineered yeast can be proposed as a model for further investigating direct and indirect mechanism(s) by which an antioxidant can rescue cells from organic acid damage; moreover, these studies will possibly provide additional targets for further strain improvements. Copyright © 2013 John Wiley & Sons, Ltd.
Retention of factual knowledge after practical training for intrapartum emergencies
Authors: Crofts Joanna F. , Fox Robert , Draycott Timothy J. , Winter Catherine , Hunt Linda P. , Akande Valentine A. 
Published: July 2013

AbstractObjectiveTo determine knowledge retention 1 year after training for intrapartum emergencies.MethodsTraining was undertaken in 6 hospitals and the Bristol Medical Simulation Centre, UK, between November 2004 and March 2005. Participants (22 junior and 23 senior doctors, 47 junior and 48 senior midwives) were randomly recruited from participating hospitals and underwent practical training at their local hospital or simulation center with or without additional teamwork training. The primary outcome was change in factual knowledge over time, as assessed by a 185‐question multiple‐choice questionnaire before and after training.ResultsMean scores at 6 (97.6 ± 23.0; n = 107) and 12 (98.2 ± 21.6; n = 98) months remained higher than those before training (79.6 ± 21.9, n = 140; both P < 0.001), but were slightly lower than those immediately after training (101.0 ± 21.3, n = 133; P < 0.001 and P = 0.007, respectively). The type of training had no effect on retention of knowledge.ConclusionTraining was associated with sustained retention of factual knowledge of obstetric emergencies care for at least 1 year. The decay in knowledge was small compared with the original gain in knowledge. Neither training location nor inclusion of teamwork training affected knowledge retention. Annual training seemed to be satisfactory for all staff groups.
Mitochondrial DNA deletions in Alzheimer's brains: A review
Authors: Phillips Nicole R. , Simpkins James W. , Roby Rhonda K. 
Published: July 2013

AbstractMitochondrial dysfunction and increased oxidative stress have been associated with normal aging and are possibly implicated in the etiology of late‐onset Alzheimer's disease (AD). DNA deletions, as well as other alterations, can result from oxidative damage to nucleic acids. Many studies during the past two decades have investigated the incidence of mitochondrial DNA deletions in postmortem brain tissues of late‐onset AD patients compared with age‐matched normal control subjects. Published studies are not entirely concordant, but their differences might shed light on the heterogeneity of AD itself. Our understanding of the role that mitochondrial DNA deletions play in disease progression may provide valuable information that could someday lead to a treatment.
EXOGENOUS AND ENDOGENOUS RISK FACTORS MANAGEMENT TO PREDICT SURRENDER BEHAVIOURS
Authors: Milhaud Xavier 
Published: July 2013

AbstractInsurers have been concerned about surrenders for a long time especially in saving business, where huge sums are at stake. The emergence of the European directive Solvency II, which promotes the development of internal risk models (among which a complete unit is dedicated to surrender risk management), strengthens the necessity to deeply study and understand this risk. In this paper, we investigate the topics of segmenting and modelling surrenders in order to better take into account the main risk factors impacting policyholders' decisions. We find that several complex aspects must be specifically dealt with to predict surrenders, in particular the heterogeneity of behaviour as well as the context faced by the insured. Combining them, we develop a new methodology that seems to provide good results on given business lines, and that moreover can be adapted for other products with little effort.
Serum lipid peroxidation markers are correlated with those in brain samples in different stress models
Authors: Celikbilek Asuman , Gocmen Ayse Yesim , Tanik Nermin , Yaras Nazmi , Yargicoglu Piraye , Gumuslu Saadet 
Published: July 2013

ObjectiveStress can stimulate increased production of oxygen radicals. We investigated the correlations between serum levels of lipid peroxidation markers and those in brain samples in different stress models.MethodsAnimals (n= 96) were divided equally into eight groups: a control group and groups treated with vitamin E (Vit E); exposed to immobilisation stress; exposed to immobilisation stress and treated with Vit E; exposed to cold stress; exposed to cold stress and treated with Vit E; exposed to both immobilisation and cold stress; and a final group exposed to both immobilisation and cold stress and treated with Vit E. Thiobarbituric acid-reactive substance (TBARS) in brain samples and levels of TBARS, corticosterone, conjugated dienes (CD), lipids, and paraoxonase-1 (PON1) activity in serum were analysed.ResultsSerum corticosterone (p< 0.001), CD (p< 0.05), lipid (p< 0.05) levels, and brain TBARS (p< 0.05) levels were significantly higher in all stress groups than in controls, and the elevated levels were reversed in the Vit E-treated stress groups (p< 0.05). Serum PON1 activity was not different among the groups (p> 0.05). Serum TBARS levels increased significantly in all stress groups (p< 0.05), but this elevation was only reversed in the group exposed to both immobilisation and cold stress and treated with Vit E (p< 0.001).ConclusionThese results suggest that serum levels of lipid peroxidation markers can be determined readily and may be useful as indicators to evaluate the effects of oxidative stress in the brain.