bluuebunny/crossref_metadata_2025 huggingface dataset:
Managing declining yields from ageing tea plantations
Authors: Kibblewhite Mark G , Prakash Sudhir , Hazarika Mridul , Burgess Paul J , Sakrabani Ruben
Published: December 2013

Strong growth in the demand for tea requires further increases in the productivity of plantations. Declining or stagnant yields are commonly observed in older plantations. Possible controlling factors for yield decline are reviewed including ageing of plants, chronic disease and sub‐optimal soil conditions such as excess soil acidity and low soil organic matter. Management options for addressing these factors are evaluated, including replanting. A systematic approach to decision‐making about replanting is presented. Practice for replanting is reviewed and it is concluded that evidence to support a general case for replanting is limited, unless based on the introduction of more productive clones and/or better plant spacing. © 2013 Society of Chemical Industry
The role of the implantable Doppler probe in free flap surgery
Authors: Wax Mark K.
Published: December 2013

Objectives/Hypothesis

Free tissue transfer has success rates greater than 95%. Approximately 10% will require reexploration for vascular compromise. Return to the operating room within 48 hours yields the highest rate of successful salvage. Our aim was to determine whether an implantable Doppler used for intraoperative/postoperative monitoring would 1) alter the pattern of detecting flap failure and 2) alter the overall incidence of flap survival.

Study Design

Prospective analysis.

Methods

Generic and study specific data was collected. Note was made at the end of the case if revision of the vascular anastomosis was performed. Data was collected for flap outcomes in the postoperative period.

Results

A total of 1,236 free tissues transfers from 2001 through 2011 were analyzed. Ninety‐four were outside the head and neck or the Doppler was not used/inadvertently discontinued. A total of 1,142 flaps make up the study cohort. One hundred thirty‐four (11.7%) intraoperative flow problems were detected, all successfully revised. Of these, 15 (11%) required postoperative revision and five (33%) were successfully salvaged, with an overall survival 93%. A total of 1,008 flaps did not require intraoperative revision, 62 required reexploration (6.1%), and 38 (61%) were salvaged. The overall survival was 97.6%. There were eight false positive (no intervention) and 10 false negatives. Sensitivity was 87% with specificity 99%.

Conclusion

Intraoperative Doppler's increase the detection of immediate/incipient vascular problems. Patients requiring revision in the operating room require revision more often in the postoperative period (P = .03) and are less likely to have successful salvage and a lower flap survival rate (P = .05).

Level of Evidence

N/A. Laryngoscope, 124:S1–S12, 2014
The hot corrosion behavior of plasma sprayed zirconia coatings stabilized with yttria, ceria, and titania in sodium sulfate and vanadium oxide
Authors: Habibi M. H. , Guo S. M.
Published: December 2013

This paper compares the hot corrosion performance of yttria‐stabilized zirconia (Zirconia‐3‐4Yttria, YSZ), ceria stabilized zirconia (Zirconia‐24Ceria‐2.5Yttria, CSZ), and titania stabilized zirconia (Zirconia‐18Titania‐10Yttria, TiSZ) coatings in the presence of molten mixture of sodium sulfate + vanadium oxide at 1050 °C. These coatings were prepared by air plasma spray (APS). Characterizations using X‐ray diffraction (XRD) and scanning electron microscope (SEM) indicate that in the case of YSZ, the reaction between sodium vanadate (NaVO3) and yttrium oxide (Y2O3) produces yttrium vanadate (YVO4) and leads to the transformation of tetragonal zirconia to monoclinic zirconia. For the CSZ coatings, by the formation of cerium vanadate (CeVO4), the amount of yttrium vanadate formed on the CSZ coating is significantly reduced, thus the amount of monoclinic phase in the TBC coating is substantially reduced. For TiSZ coating, although some minor reactions happened and some titanium vanadate (TiVO4) ribbons formed on the surface of coating, tetragonal zirconia was stable after hot corrosion test and no monoclinic zirconia was formed. Comparing to YSZ and CSZ under a temperature of 1050 °C, TiSZ coating is found to be more stable, both thermally and chemically, and exhibits a better hot corrosion resistance.
Electrochemical corrosion studies of ultrafine‐grained aluminium alloy EN AW‐6063
Authors: Krüger L. , Schwarz F. , Mandel M. , Hockauf M.
Published: December 2013

The electrochemical corrosion behaviour of ultrafine‐grained EN AW‐6063 processed by equal‐channel angular pressing (ECAP) was investigated in a 0.01 M sodium chloride solution for different numbers of ECAP‐passes. Some of the ECAPed samples were additionally heat treated and show better corrosion resistance in their potentiodynamic polarisation behaviour than the samples without the heat treatment. Investigations of the surface topology indicate more uniform corrosion when compared to the initial state without ECAP and heat treatment. The results of the microscopic observations confirm that the corrosion behaviour is improved by increasing the number of ECAP‐passes and by additional heat treatment.
Microcapillary polarization measurements of friction stir spot welds made in AZ31B magnesium alloy
Authors: Savguira Y. , North T. H. , Thorpe S. J.
Published: December 2013

Microcapillary polarization procedures were optimized to examine the corrosion characteristics of the various microstructural zones developed during friction stir spot welds made in AZ31 magnesium alloy. Tungsten carbide tracing confirmed the location and shape of the stir zone in the weldment. The stir zone was determined to be the noble region while the base metal and the thermo‐mechanically affected zone were found to be active. The thermo‐mechanically affected zone was found to be most susceptible to localized corrosion attack due to its proximity to the noble stir zone, and the subsequent formation of a macrogalvanic cell. Corrosion rates of individual weld regions were measured.
Type II hot corrosion: Behavior of CMSX‐4 and IN738LC as a function of corrosion environment
Authors: Sumner J. , Encinas‐Oropesa A. , Simms N. J. , Nicholls J. R.
Published: December 2013

CMSX‐4 and IN738LC, industrial gas turbine (IGT) aerofoil alloys with low (6.5 wt%) and high (16 wt%) chromium contents respectively, were exposed to type II hot corrosion conditions (700 °C, SOX in air, alkali sulphate/chloride deposits) for up to 1000 h. By comparing detailed pre‐ and post‐exposure dimensional metrology from the samples, the fraction of each sample's surface undergoing the incubation stage (lower levels of sample damage due to the presence of a protective scale) or the propagation stage (higher levels of sample damage due to the direct attack of the base alloy) of type II hot corrosion damage was determined. Corrosion pit development under type II conditions may be described as an extreme event. As such, the transition from incubation to propagation may be modelled using Weibull statistics, which were found to give a good fit to the spread of incubation lifetimes in the exposed IN738LC samples. Much shorter incubation lifetimes were found for the lower chromium content alloy (CMSX‐4). Propagation rates for CMSX‐4 were found not to be constant over time. Instead, when exposed to the higher deposition fluxes, the propagation rates fell after long exposure times as the resultant deposit/corrosion product inhibited the transportation of reactive species. This improved, quantitative understanding of the transition from incubation to propagation damage under type II hot corrosion conditions will assist in the development of quantitative hot corrosion damage models, enhancing IGT component lifetime prediction.
Multifunctional Electrospun Nanofibers Prepared from Poly((N‐isopropylacrylamide)‐co‐(N‐hydroxymethylacrylamide)) and Their Blends with 1,2‐Diaminoanthraquinone for NO Gas Detection
Authors: Chen Liang‐Nien , Chiu Yu‐Cheng , Hung Jr‐Jian , Kuo Chi‐Ching , Chen Wen‐Chang
Published: December 2013

Multifunctional electrospun (ES) nanofibers are successfully prepared from blends of poly((N‐isopropylacrylamide)‐co‐(N‐hydroxymethylacrylamide)) (poly(NIPAAm‐co‐NMA)) with NO(g)‐responsive 1,2‐diaminoanthraquinone (DAQ). Different compositions of poly(NIPAAm‐co‐NMA) are synthesized by free radical polymerization. The NMA content significantly affects the stability of the ES nanofibers in water and the NO(g) detection due to a change of the hydrophilic/hydrophobic characteristics. In addition, the fibers exhibit a significant volume (or hydrophilic/hydrophobic) change during the heating and cooling cycle between 25 and 50 °C, attributed to the lower critical solution temperature (LCST) characteristic of the thermoresponsive NIPAAm moiety. On the other hand, a distinct on/off switching of the optical absorption spectra and high color contrast on detecting the NO(g) are observed using the ES nanofibers of poly(NIPAAm‐co‐NMA)/DAQ blends. The high surface/volume of ES fibers enhance the sensitivity and responsive speed, compared with that of drop‐cast film. The above studies suggest that the prepared multifunctional ES nanofibers have potential applications in environmentally sensing devices.

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Flocculation Efficiency of Novel Amphiphilic Starch Derivatives: A Comparative Study
Authors: Bratskaya Svetlana Y. , Genest Sabine , Petzold‐Welcke Katrin , Heinze Thomas , Schwarz Simona
Published: December 2013

Flocculation properties of amphiphilic starch derivatives of varying degrees of substitution (DS) of benzyl‐ and 2‐hydroxypropyl‐trimethylammonium moieties have been investigated in dispersions of kaolin, calcium carbonate, and silica. Moderate hydrophobic substitution leads to a decrease of efficient flocculant dose and increase of flocculation window width. Samples with high DS of hydrophobic moieties are effective only at significantly higher doses but in a broader concentration range compared to solely cationic ones of the same DS. Joint analysis of adsorption isotherms and flocculation test data has revealed that the surface coverage required to induce phase separation ranges between 10–25% and is minimal for amphiphiles, whose floc sizes are moreover less dependent on the flocculant dose.
Elaboration of Thermoresponsive Supramolecular Diblock Copolymers in Water from Complementary CBPQT4+ and TTF End‐Functionalized Polymers
Authors: Sambe Léna , Stoffelbach François , Poltorak Katarzyna , Lyskawa Joël , Malfait Aurélie , Bria Marc , Cooke Graeme , Woisel Patrice
Published: December 2013

A well‐defined poly(N‐isopropyl acrylamide) 1 incorporating at one termini a cyclobis(paraquat‐p‐phenylene) (CBPQT4+) recognition unit is prepared via a RAFT polymerization followed by a copper‐catalyzed azide‐alkyne cycloaddition (CuAAC). 1H NMR (1D, DOSY), UV–vis and ITC experiments reveal that polymer 1 is able of forming effective host–guest complexes with tetrathiafulvalene (TTF) end‐functionalized polymers in water, thereby leading to the formation of non‐covalently‐linked double‐hydrophilic block copolymers. The effect of the temperature on both the LCST phase transition of 1 and its complexes and on CBPQT4+/TTF host–guest interactions is investigated.

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Current trends in mass spectrometry of peptides and proteins: Application to veterinary and sports‐doping control
Authors: van den Broek Irene , Blokland Marco , Nessen Merel A. , Sterk Saskia
Published: December 2013

Detection of misuse of peptides and proteins as growth promoters is a major issue for sport and food regulatory agencies. The limitations of current analytical detection strategies for this class of compounds, in combination with their efficacy in growth‐promoting effects, make peptide and protein drugs highly susceptible to abuse by either athletes or farmers who seek for products to illicitly enhance muscle growth. Mass spectrometry (MS) for qualitative analysis of peptides and proteins is well‐established, particularly due to tremendous efforts in the proteomics community. Similarly, due to advancements in targeted proteomic strategies and the rapid growth of protein‐based biopharmaceuticals, MS for quantitative analysis of peptides and proteins is becoming more widely accepted. These continuous advances in MS instrumentation and MS‐based methodologies offer enormous opportunities for detection and confirmation of peptides and proteins. Therefore, MS seems to be the method of choice to improve the qualitative and quantitative analysis of peptide and proteins with growth‐promoting properties. This review aims to address the opportunities of MS for peptide and protein analysis in veterinary control and sports‐doping control with a particular focus on detection of illicit growth promotion. An overview of potential peptide and protein targets, including their amino acid sequence characteristics and current MS‐based detection strategies is, therefore, provided. Furthermore, improvements of current and new detection strategies with state‐of‐the‐art MS instrumentation are discussed for qualitative and quantitative approaches. © 2015 Wiley Periodicals, Inc. Mass Spec Rev 34: 571–594, 2015.
Referral and diagnostic trends in pediatric electromyography in the molecular era
Authors: Karakis Ioannis , Liew Wendy , Darras Basil T. , Jones H. Royden , Kang Peter B.
Published: December 2013

Introduction: Major advances in genetic analysis and neuroimaging have modified the traditional diagnostic approach for neuromuscular disorders. The purpose of this study was to investigate the role of electromyography (EMG) in the molecular era. Methods: We retrospectively surveyed reports of all EMG studies performed at Boston Children's Hospital from 2001 through 2011. Data were collected on study numbers, patient ages, referring provider subspecialty, study indication, electrophysiological diagnosis, and study utility. Results: A total of 2100 studies were performed. The volume increased from ∽160 to ∽250 studies/year. There was a trend toward studying older children. Neurologists, including neuromuscular specialists, constituted the major referral pool, whereas referrals from orthopedics increased steadily. Polyneuropathies followed by mononeuropathies were the most common indications and diagnoses. Fifty‐seven percent of studies were normal. EMG provided meaningful information in 94% of cases. Conclusion: EMG continues to play a cardinal role in the diagnosis of pediatric neuromuscular disorders, although its practice paradigm is evolving. Muscle Nerve 50:244–249, 2014
Development of the distinct lattice spring model for large deformation analyses
Authors: Zhao G.‐F.
Published: December 2013

This study develops the distinct lattice spring model (DLSM) for geometrically nonlinear large deformation problems. The formulation of a spring bond deformation under a large deformation is derived under the Lagrange framework using polar decomposition. The results reveal that the DLSM's stiffness matrix under small deformations is the tangent stiffness matrix of the DLSM under large deformations. The formulation of the spring bond internal force under a given configuration is also presented and can be used to calculate the unbalanced force. Using these formulations, three nonlinear solving methods (the Euler method, modified Euler method, and Newton method) are developed for the DLSM with which to tackle large deformation problems. To investigate the performance of the developed model, three numerical examples involving large deformations are presented, the results of which are also in good agreement with the analytical and finite element method solutions. Copyright © 2013 John Wiley & Sons, Ltd.
Managing Organizational Social Capital through Value Configurations
Authors: Schnurbein Georg von
Published: December 2013

Nonprofits are said to serve as places for the reproduction of social capital. However, little is known about how to manage social capital in a nonprofit. This article presents a theory‐based perspective on how to plan, execute, and measure social capital production in a nonprofit organization. By using the concept of value configurations as a method to analyze and describe the creation of organizational social capital, bonding and bridging social capital can be managed in alternative ways. In a value shop framework, the participants are more homogeneous, and growth is heavily based on referrals and reputation as well as the quality of the members. Organizations managed as value shops will foster bonding social capital. In contrast, a value network framework incorporates more likely heterogeneous, multilevel participants that add legitimacy to the network. Organizations in this framework will strengthen the evolution of bridging social capital.
Retrospective evaluation of antithrombin III supplementation in neonates and infants receiving enoxaparin for treatment of thrombosis
Authors: Corder Amy , Held Kristin , Oschman Alexandra
Published: December 2013

Background

Thromboembolic events are occurring at increasing rates in neonates and infants. At Children's Mercy Hospitals and Clinics, antithrombin III (AT3) concentrates are often used in combination with enoxaparin to supplement physiologically low AT3 levels. Theoretically, AT3 enhances the anticoagulant activity of enoxaparin and results in decreased time to therapeutic anti‐Xa levels. No data exist on use of AT3 for this indication.

Procedure

This retrospective study compared time to therapeutic anti‐Xa levels in patients <1 year of age receiving enoxaparin with AT3 (Group 1) and without AT3 (Group 2) for treatment of thrombosis. Primary objective was to compare time to therapeutic anti‐Xa levels (0.5–1 U/ml) between groups. Secondary objectives included comparison of the initial and therapeutic dose of enoxaparin, enoxaparin dose changes, AT3 supplementation, and level monitoring. Bleeding events and cost were also evaluated. Statistical tests included Schuirmann's two one‐sided tests for equivalence and general linear models/logistic regression for independent effects of age, critical illness, and timing of AT3.

Results

Mean time to therapeutic anti‐Xa levels were not equivalent between Groups 1 and 2 (80.7 vs. 65.2 hours; P = 0.28). Initial enoxaparin dose and number of dose changes were equivalent. Group 1 required higher doses of enoxaparin to achieve therapeutic anti‐Xa levels. Age, critical illness, and timing of AT3 had no effect on time to therapeutic anti‐Xa levels. Bleeding events were not equivalent between Groups 1 and 2 (14.3% vs. 3.9%; P = 0.55).

Conclusion

Supplementation with AT3 did not decrease time to therapeutic anti‐Xa levels, added significant cost, and was associated with increased bleeding events. Pediatr Blood Cancer 2014;61:1063–1067. © 2013 Wiley Periodicals, Inc.
Uptake, Biological Fate, and Toxicity of Metal Oxide Nanoparticles
Authors: Llop Jordi , Estrela‐Lopis Irina , Ziolo Ronald F. , González Africa , Fleddermann Jana , Dorn Marco , Vallejo Vanessa Gomez , Simon‐Vazquez Rosana , Donath Edwin , Mao Zwengei , Gao Changyou , Moya Sergio E.
Published: December 2013

Studies of the uptake, biological fate, and toxicity of several metal oxide nanoparticles (NPs), such as Al2O3, TiO2, CeO2‐x, and ZnO NPs undertaken in the European Project “Health Impact of Engineered Metal and Metal Oxide Nanoparticles: Response, Bioimaging and Distribution at Cellular and Body Level” are reviewed here. Metal oxide NPs are radiolabeled by direct proton bombardment of commercially available NPs or enriched during synthesis with 18O to generate 18F after‐proton bombardment. Size, degree of aggregation, and zeta potential of the metal oxide NPs are studied in the presence of proteins and cell media. NP uptake and intracellular fate are followed by ion beam microscopy (IBM), transmission electron microscopy, confocal Raman microscopy and confocal laser scanning microscopy. IBM allows for the quantification of the intracellular dose of NPs. Cell viability studies and the immune response are studied “in vitro” in primary alveoli, and immortalized cell lines. Biodistribution studies in rodents are performed with positron emission tomography following different exposure routes: intravenous, oral, topical, and inhalation using radiolabelled NPs. Activity per organ is quantified for the different uptake routes and with the time.
Optimizing the electrical power output of a thermogenerator with the Gerstenmaier/Wachutka approach
Authors: Seifert Wolfgang , Pluschke Volker , Zabrocki Knud
Published: December 2013

Gerstenmaier and Wachutka have published in PRE 86, 056703 (2012) a new approach (in this paper denoted as G/W approach) to optimizing the material grading in thermoelectric (TE) converters by means of a generalized Lagrange multiplier method. This powerful method allows considering all relevant performance maximization problems within both the “x‐domain” and the “T‐domain”; in the latter case the compatibility approach has been recovered by independent proof. Here, we adapt the G/W approach to optimizing spatial TE material profiles in order to get maximum electrical power output of a graded thermogenerator with fixed length. The new findings are compared with results previously published. This particularly applies the comparison of the optimal Seebeck coefficients for maximum efficiency and maximum power output.
Thermodynamic modelling of crystalline unary phases
Authors: Palumbo M. , Burton B. , Costa e Silva A. , Fultz B. , Grabowski B. , Grimvall G. , Hallstedt B. , Hellman O. , Lindahl B. , Schneider A. , Turchi P. E. A. , Xiong W.
Published: December 2013

Progress in materials science through thermodynamic modelling may rest crucially on access to a database, such as that developed by Scientific Group Thermodata Europe (SGTE) around 1990. It gives the Gibbs energy of the elements in the form of series as a function of temperature, i.e. essentially a curve fitting to experimental data. In the light of progress in theoretical understanding and first‐principles calculation methods, the possibility for an improved database description of the thermodynamics of the elements has become evident. It is the purpose of this paper to provide a framework for such work. Lattice vibrations, which usually give the major contribution to , are treated in some detail with a discussion of neutron scattering studies of anharmonicity in aluminium, first‐principles calculations including ab initio molecular dynamics (AIMD), and the strength and weakness of analytic model representations of data. Similarly, electronic contributions to are treated on the basis of the density of states for metals, with emphasis on effects at high T. Further, we consider below 300 K, which is not covered by SGTE. Other parts in the paper discuss metastable and dynamically unstable lattices, in the region of superheated solids and the requirement on a database in the calculation of phase diagrams.
Optically Controlled Pore Formation in Self‐Sealing Giant Porphyrin Vesicles
Authors: Huynh Elizabeth , Lovell Jonathan F. , Fobel Ryan , Zheng Gang
Published: December 2013

Efforts to develop self‐contained microreactors and artificial cells have been limited by difficulty in generating membranes that can be robustly and repeatedly manipulated to load and release cargo from phospholipid compartments. Here we describe a purely optical method to form pores in a membrane generated from porphyrin‐phospholipid conjugates electro‐assembled into microscale giant porphyrin vesicles and manipulated using confocal microscopy. The pores in the membrane resealed within a minute allowing for repeated pore formation with precise spatial and temporal control and optical gating to allow selective diffusion of biomolecules across the membrane. Temporal control of pore formation was illustrated by performing sequential DNA hybridization reactions. A biotin‐avidin based strategy was developed to selectively attach enzymes to the interior of the vesicle, demonstrating spatial control and the potential of giant porphyrin vesicles as versatile microreactors.
Surface Coating‐Dependent Cytotoxicity and Degradation of Graphene Derivatives: Towards the Design of Non‐Toxic, Degradable Nano‐Graphene
Authors: Li Yingjie , Feng Liangzhu , Shi Xiaoze , Wang Xiaojing , Yang Yinlong , Yang Kai , Liu Teng , Yang Guangbao , Liu Zhuang
Published: December 2013

With the increasing interests of using graphene and its derivatives in the area of biomedicine, the systematic evaluation of their potential risks and impacts to biological systems is becoming critically important. In this work, we carefully study how surface coatings affect the cytotoxicity and extracellular biodegradation behaviors of graphene oxide (GO) and its derivatives. Although naked GO could induce significant toxicity to macrophages, coating those two‐dimensional nanomaterials with biocompatible macromolecules such as polyethylene glycol (PEG) or bovine serum albumin (BSA) could greatly attenuate their toxicity, as independently evidenced by several different assay approaches. On the other hand, although GO can be gradually degraded through enzyme induced oxidization by horseradish peroxidase (HRP), both PEG and BSA coated GO or reduced GO (RGO) are rather resistant to HRP‐induced biodegradation. In order to obtain biocompatible functionalized GO that can still undergo enzymatic degradation, we conjugate PEG to GO via a cleavable disulfide bond, obtaining GO‐SS‐PEG with negligible toxicity and considerable degradability, promising for further biomedical applications.
Influence of the 20‐week anomaly scan on prenatal diagnosis and management of fetal facial clefts
Authors: Ensing S. , Kleinrouweler C. E. , Maas S. M. , Bilardo C. M. , Van der Horst C. M. A. M. , Pajkrt E.
Published: December 2013

Objective

To investigate trends in prenatal diagnosis and termination of pregnancy rates in cases of fetal cleft lip with or without cleft palate (CL±P), before and after the introduction in The Netherlands of the 20‐week anomaly scan in 2007, and to assess the accuracy of this scan for the diagnosis of facial clefts.

Methods

This was a retrospective cohort study of consecutive cases of CL±P diagnosed in 2001–2010 in the referral region of the Academic Medical Centre. Cases diagnosed prenatally were identified from the hospital's database. These data, grouped according to the periods before and after the introduction of the routine 20‐week anomaly scan, were compared with data of all cases managed by the multidisciplinary cleft team, which services the same region, to identify cases of CL±P that were not seen prenatally.

Results

We identified 123 cases of CL±P diagnosed prenatally, of which 76% (93/123) were diagnosed before 24 weeks. In one case, the CL±P was not confirmed after birth. There were 46 cases with associated structural anomalies and 76 isolated cases. The median gestational age at diagnosis decreased by 2 weeks after 2007 (P = 0.02). The proportion of isolated clefts detected prenatally increased significantly after 2007 (P < 0.0001), whereas the proportion of associated clefts remained stable over the years (P = 0.426). The overall detection rate of CL±P increased from 43% before 2007 to 86% after 2007 (P < 0.0001), without an increase in terminations of pregnancy.

Conclusion

Introduction of the routine fetal anomaly scan has decreased the gestational age at diagnosis of CL±P and has increased the proportion diagnosed prenatally, without a significant change in the number of terminations of pregnancy. Copyright © 2013 ISUOG. Published by John Wiley & Sons Ltd
Time to stop investing in carbon capture and storage and reduce government subsidies of fossil‐fuels
Authors: Stephens Jennie C.
Published: December 2013

Government investment in carbon capture and storage (CCS) is a large and expensive fossil‐fuel subsidy with a low probability of eventual societal benefit. Within the tight resource constrained environments that almost all governments are currently operating in, it is irresponsible to sustain this type of subsidy. CCS has been promoted as a ‘bridging’ technology to provide CO2 reductions until non‐fossil‐fuel energy is ramped up. But the past decade of substantial government investment and slow progress suggests that the challenges are many, and it will take longer to build the CCS bridge than to shift away from fossil‐fuels. Optimism about the potential of CCS is based primarily on research on technical feasibility, but very little attention has been paid to the societal costs of governments perpetuating fossil‐fuels or to the sociopolitical requirements of long‐term regulation of CO2 stored underground. Deep systemic change is needed to alter the disastrous global fossil‐fuel trajectory. Government investment in CCS and other fossil‐fuel technologies must end so that the distraction and complacency of the false sense of security such investments provide are removed. Instead of continuing to invest billions in CCS, governments should invest more aggressively in technologies, policies, and initiatives that will accelerate a smooth transition to non‐fossil‐fuel‐based energy systems. We need to divest from perpetuating a fossil‐fuel infrastructure, and invest instead in social and technical changes that will help us prepare to be more resilient in an increasingly unstable and unpredictable future. WIREs Clim Change 2014, 5:169–173. doi: 10.1002/wcc.266

This article is categorized under:

Climate Economics > Economics of Mitigation

The Carbon Economy and Climate Mitigation > Decarbonizing Energy and/or Reducing Demand
Financial modeling with heavy‐tailed stable distributions
Authors: Nolan John P.
Published: December 2013

The aim of this article was to give an accessible introduction to stable distributions for financial modeling. There is a real need to use better models for financial returns because the normal (or bell curve/Gaussian) model does not capture the large fluctuations seen in real assets. Stable laws are a class of heavy‐tailed probability distributions that can model large fluctuations and allow more general dependence structures. WIREs Comput Stat 2014, 6:45–55. doi: 10.1002/wics.1286

This article is categorized under:

Applications of Computational Statistics > Computational Finance

Statistical and Graphical Methods of Data Analysis > Multivariate Analysis

Statistical and Graphical Methods of Data Analysis > Robust Methods
The nature of friction: A critical assessment
Authors: Hsu Stephen , Ying Charles , Zhao Fei
Published: December 2013

Friction is an essential part of human experience. We need traction to walk, stand, work, and drive. At the same time, we need energy to overcome the resistance to motion, hence, too much friction costs excess energy to perform work, introducing inefficiencies. In the 21st century, we are facing the dual challenges of energy shortage and global warming from burning fossil fuels. Therefore, the ability to control friction has become a top priority in our world today. Yet our understanding of the fundamental nature of friction is still lacking.

Friction has always been a subject of curiosity. Intensive study of the origin of friction began in the 16th century, after the pioneering work by Leonardo da Vinci. Yet progress in understanding the nature of friction has been slow, hampered by the lack of instrument to measure friction precisely. Ingenious experiments performed by Amontons, Coulomb, and others have yielded important insights to build the foundation of our understanding. Beginning in the late 1800s and early 1900s, the advent of steam engines, locomotives, followed by the automobiles airplanes, and space exploration demands a clear understanding of friction and the ability to control it for the machinery to last. Significant progress on how to apply and control friction in engineering friction was made through trial and error. At the beginning of the 21st century, a new dimension of nanoscale friction came into the picture in conjunction with the arrival of nanotechnology. Our understanding of atomic and molecular friction has been expanding rapidly. However, integration of the new found knowledge of nanofriction into engineering practices has been elusive. Why? What is the scaling relationship between atomic friction and macro-friction? Is it possible to predict friction at the macro-level from nanoscale results? Why nanofriction values often do not agree with the macrofriction values given the same materials pair? Could it be there is a length scale dependent characteristic friction value?

In engineering practice, progress since the 1980s has been slow. Most of the effort has been focused on lubrication research such as elastohydrodynamic theories and solid lubricants. Friction mechanisms and failures have received relative little attention while nanofriction received much of the attention.

Today, energy efficiency and renewable energy generation demand our immediate attention while we seek reduction in carbon emission. The ability to control friction becomes an essential step in seeking sustainable technologies. Friction, after all, is an indicator of energy efficiency. If we can reduce the unnecessary parasitic energy losses and increase our current energy efficiency, it will give us time to develop alternative energy sources. This paper examines our current understanding of friction, filling some voids with experimental data, and attempts to integrate the various pieces to identify the gaps of our knowledge, hopefully to spark new avenues of investigations into this important area.
Effects of undernourishment, recurrent seizures and enriched environment during early life in hippocampal morphology
Authors: Alvarez Paula Steffen , Simão Fabrício , Hemb Marta , Xavier Léder Leal , Nunes Magda Lahorgue
Published: December 2013

It has been recently shown that enriched environment led to a significant benefit in learning and retention of visual–spatial memory, being able to reverse the cognitive impairment generated by undernourishment and recurrent seizures. We investigated the hippocampal morphological effects of recurrent seizures and undernourishment early in life in Wistar rats and the possible benefits produced by the enriched environment in these conditions. The morphological parameters stereologically evaluated were hippocampal volume, thickness of pyramidal stratum of the CA1 subfield and neuronal and glial densities in the same subfield. Male Wistar rats were divided into eight groups including nourished, nourished + enriched environment, nourished + recurrent seizures, nourished + recurrent seizures + enriched environment, undernourished, undernourished + enriched environment, undernourished + recurrent seizures and undernourished + recurrent seizures + enriched environment. Undernourishment model consisted in nutritional deprivation regimen from post‐natal day 2 (P2) to P15. From P8 to P10, recurrent seizures group were induced by flurothyl three times per day. Enriched environment groups were exposed between P21 and P51. Our main findings were: (1) animals submitted to the enriched environment showed an increased hippocampal volume; (2) enriched environment promotes increases in the thickness of the pyramidal layer in hippocampal CA1 subfield in animals nourished and undernourished with recurrent seizures; (3) undernourishment during early development decreased neuronal density in CA1 and CA3 subfields. Our findings show that these three conditions induces important changes in hippocampal morphology, the most deleterious changes are induced by undernourishment and recurrent seizures, while more beneficial morphological changes are produced by enriched environment.
Intrathecal Baclofen Therapy After Liver Transplant in a Patient With Crigler‐Najjar Syndrome
Authors: Pratini Napala R. , Neufeld Jacob A.
Published: December 2013

Crigler‐Najjar syndrome (CNS) is described as severe infantile, nonhemolytic, unconjugated hyperbilirubinemia and is divided into type I and type II according to the patient's response to phenobarbital treatment. Patients with type I CNS usually require a liver transplant. These patients often have spasticity and dystonia, both of which can be treated with intrathecal baclofen therapy. We present the case of a patient with CNS type I who underwent a liver transplant followed years later by intrathecal baclofen therapy. To our knowledge, this article provides the first report of a patient with CNS being treated for dystonia with an intrathecal baclofen pump. Despite his complicated history, this patient has remained medically stable after both interventions.
Luria and His Lasting Influence on Test Batteries in Neuropsychological and Intelligence Assessment
Authors: Bornschlegl Mona , Petermann Franz
Published: December 2013

Luria still influences contemporary test batteries in neuropsychological and intelligence assessment. Characteristic of his exam are: process-orientation, qualitative approach, adaptive administration, and hypothesis testing. Luria covers a broad range of functional areas (14 areas with 89 tasks total). This review analyses seven contemporary test batteries related to Luria. For adults these are in neuropsychology: LNI, KBNA, K-SNAP, and in Intelligence assessment: KAIT. For children these are in neuropsychology: NEPSY-II, and in Intelligence assessment: CAS, KABC-II. These test batteries cover significantly less functional areas (3 to 11) and have fewer Subtests (4 to 32). Analogies to Luria’s exam can be found in test administration, mostly adaptive testing. With special subjects (children, elderly) this helps preventing resistance and fatigue during testing. (119 words)
Fault diagnostic algorithm for three‐level neutral point clamped AC motor drives, based on the average current Park's vector
Authors: Mendes Andre M. Santos , Abadi Mohsen Bandar , Cruz Sérgio Manuel A.
Published: December 2013

This study presents a new fault diagnostic technique for a semiconductor open‐circuit fault in a neutral‐point clamped inverter, based on the average current Park's vector approach. This method relies on the measurement of two motor line currents and is able to perform a complete diagnosis in less than half of the inverter output current period. The implementation of this diagnostic technique requires no additional current or voltage sensors besides the ones already used by the control algorithm of the converter. The diagnostic method uses the modulus and angle of the normalised average current Park's vector to detect the fault and identify the faulty insulated gate bipolar transistor (IGBT) pair, respectively. Simultaneously, the normalised average values corresponding to the positive and negative parts of the motor supply currents waveforms are used to identify the inner faulty IGBTs with even and odd numbers, respectively. The diagnostic method is also robust to transient conditions imposed by load and speed variations. The performance and effectiveness of the proposed diagnostic technique are validated both by the simulation and experimental results.
Response of HTS tapes to a parallel ac magnetic field in the vicinity of the superconducting transition
Authors: Fisher L. M. , Voloshin I. F. , Yampol'skii V. A.
Published: December 2013

We have studied the temperature dependence of the ac magnetic susceptibility χ(T)=χ′(T)+iχ″(T) of YBCO tapes in a parallel magnetic field in both the Meissner and vortex states. For the vortex state, we have observed two maximums in the χ″(T) dependence. The position and the magnitude of one of these maxima are described well by the nonlocal critical state model. The second maximum and corresponding kink in the function χ′(T) observed close to the temperature Tc of the superconducting transition are unexpected. The origin of this maximum cannot be explained within the usual notions of the high-temperature superconductivity. We suppose that it is related to some magnetic restructuring in the superconducting layer just above Tc. Our results put a question on the correctness of the interpretation of some previous microwave experiments.
On the determination of the quasiparticle scattering rate in unconventional superconductors by microwave surface impedance
Authors: Cherpak N. T. , Barannik A. A. , Prozorov R. , Tanatar M. , Velichko A. V.
Published: December 2013

As found from numerous microwave experiments on the unconventional Fe-based superconductors, the temperature dependence of the quasiparticle scattering rate τ−1 cannot be accurately described within the framework of standard Drude module in the popular approximation of ωτ ≪ 1, where ω is the signal frequency. To account for the discrepancy, we have extended the classical Drude model for the case of arbitrary values of ωτ, and obtained the expression for τ−1 as a function of experimentally measurable quantities, namely the real and imaginary parts of the microwave surface impedance. We then show the temperature dependence of τ−1 in superconducting Ba(Fe1-xCox)2As2 single crystal pnictide derived from the Ka-band surface impedance measurements within the framework of the modified expression. The measurements indicate the extent to which assumption of ωτ ≪ 1 gives results different from those obtained without this restriction, i.e., incorrect results.
Spin-neurons: A possible path to energy-efficient neuromorphic computers
Authors: Sharad Mrigank , Fan Deliang , Roy Kaushik
Published: December 2013

Recent years have witnessed growing interest in the field of brain-inspired computing based on neural-network architectures. In order to translate the related algorithmic models into powerful, yet energy-efficient cognitive-computing hardware, computing-devices beyond CMOS may need to be explored. The suitability of such devices to this field of computing would strongly depend upon how closely their physical characteristics match with the essential computing primitives employed in such models. In this work, we discuss the rationale of applying emerging spin-torque devices for bio-inspired computing. Recent spin-torque experiments have shown the path to low-current, low-voltage, and high-speed magnetization switching in nano-scale magnetic devices. Such magneto-metallic, current-mode spin-torque switches can mimic the analog summing and “thresholding” operation of an artificial neuron with high energy-efficiency. Comparison with CMOS-based analog circuit-model of a neuron shows that “spin-neurons” (spin based circuit model of neurons) can achieve more than two orders of magnitude lower energy and beyond three orders of magnitude reduction in energy-delay product. The application of spin-neurons can therefore be an attractive option for neuromorphic computers of future.
Localized rotating convection with no-slip boundary conditions
Authors: Beaume Cédric , Kao Hsien-Ching , Knobloch Edgar , Bergeon Alain
Published: December 2013

Localized patches of stationary convection embedded in a background conduction state are called convectons. Multiple states of this type have recently been found in two-dimensional Boussinesq convection in a horizontal fluid layer with stress-free boundary conditions at top and bottom, and rotating about the vertical. The convectons differ in their lengths and in the strength of the self-generated shear within which they are embedded, and exhibit slanted snaking. We use homotopic continuation of the boundary conditions to show that similar structures exist in the presence of no-slip boundary conditions at the top and bottom of the layer and show that such structures exhibit standard snaking. The homotopic continuation allows us to study the transformation from slanted snaking characteristic of systems with a conserved quantity, here the zonal momentum, to standard snaking characteristic of systems with no conserved quantity.
Dynamics of the resistive state of a narrow superconducting channel in the ac voltage driven regime
Authors: Yerin Yu. S. , Fenchenko V. N.
Published: December 2013

Within the framework of the time-dependent Ginzburg–Landau equations, the dynamics of the order parameter in narrow superconducting channels of different lengths is investigated in the ac voltage-driven regime. The resistive state of the system at low frequencies of the applied voltage is characterized by the formation of time-periodic groups of oscillating phase-slip centers (PSCs). Increasing the frequency reduces the lifetime of these periodic groups. Depending on the length of the channel, the ac voltage either tends to restore the state with a single central PSC in periodic groups or minimizes the number of forming PSCs and induces their ordering in the system. For relatively short channels, a further increase in frequency leads to the suppression of the order parameter without PCS formation. For the systems with the channel length exceeding the specified limit, the formation of PSC starts after a certain time delay which increases rapidly with frequency. The current-voltage characteristics of a relatively short channel at different applied voltage frequencies are calculated. It is found that the current-voltage characteristics exhibit a stepped structure, where the height of the first step is determined by the quadruple value of the Josephson frequency.
High-frequency ESR spectra of the type Ib synthetic diamond and nanodiamond at low temperatures
Authors: Khatsko E. , Kobets M. , Dergachev K. , Kulbickas A. , Rasteniene L. , Vaisnoras R.
Published: December 2013

The ESR absorption spectra on paramagnetic centers in the type Ib bulk diamond and nanodiamond powder were studied before and after irradiation with high energy electrons (2 MeV) for a wide range of frequencies (70–120 GHz) and temperatures (4.2–90 K). The absorption lines related to the nickel-ion growth catalyst Ni1+ and single nitrogen paramagnetic center N0 were observed in the ESR spectrum of bulk diamond. In the nanodiamond, the absorption lines of the paramagnetic centers with dangling bonds on the surface of the nanodiamond crystallites (surface defects) and the sidelines related to the hyperfine interaction were observed in the ESR spectra.