bluuebunny/crossref_metadata_2025 huggingface dataset:
Haptic Devices
Authors: Bianchi Matteo
Published: November 2016

Haptics, that is, the science of touch, represents a vibrating, multidisciplinary research topic that crosses the boundaries between neuroscience, psychophysics, robotics, and engineering. While in the neuroscientific community the main focus of haptics is the study of neural and perceptual mechanisms of human tactual sensing, from a technological point of view it aims at suitably replicating such mechanisms through artificial systems (namely, haptic interfaces) for human–machine interaction. In this article, we review the main aspects of human touch perception, and how they can be applied to the design of haptic devices to render different types of touch‐related information. We describe the principal components of the mechatronic architecture of haptic systems, their main application areas, and issues related to their control and stability. Finally, we briefly review wearable haptic systems and discuss the role of affective touch, that is, the emotional component of touch, for the design of new interfaces for human–robot communication.
Spatial Modulation for Multiple‐Antenna Communication
Authors: Renzo M. Di , Haas H. , Ghrayeb A. , Hanzo L. , Sugiura S.
Published: November 2016

The key challenge of future mobile communication networks is to strike an attractive compromise between the wireless network's area spectral efficiency and the energy efficiency. This necessitates new approaches to wireless system design, embracing a rich body of existing knowledge –especially in the field of multiple‐input–multiple‐output (MIMO) techniques. Hence, in this article, we describe spatial modulation (SM) that constitutes a promising new concept of wireless system design conceived for reducing the number of high‐cost RF front ends compared to other MIMO implementations. The concept of SM has recently established itself as a beneficial transmission paradigm, subsuming numerous members of the MIMO system family. Research activities on SM have reached sufficient maturity to motivate its comparison against state‐of‐the‐art MIMO systems, as well as to inspire its application in emerging wireless communication systems. Furthermore, it has received sufficient research attention to motivate its implementation in testbeds and it holds the promise of stimulating further vigorous inter‐disciplinary research in the years to come, especially in the emerging market of the Internet of Things (IoT).
Neuromorphic Systems
Authors: Bartolozzi C. , Benosman R. , Boahen K. , Cauwenberghs G. , Delbrück Tobi , Indiveri Giacomo , Liu Shih‐Chii , Furber S. , Imam N. , Linares‐Barranco Bernabé , Serrano‐Gotarredona Teresa , Meier K. , Posch C. , Valle M.
Published: November 2016

This article reviews a wide spectrum of state‐of‐the‐art neuromorphic systems, ranging from its principles, sensory elements, and processing aspects to large‐scale example systems and commercial outlook. It does not aim to provide a full coverage of present knowledge, but simply provide a comprehensive summary with many pointers to further readings.
Memetic Algorithms: A Contemporary Introduction
Authors: Cotta Carlos , Gallardo Jose E. , Mathieson Luke , Moscato Pablo
Published: November 2016

Memetic algorithms (MAs) constitute a search and optimization paradigm based on the orchestrated interplay between global and local search components, and have the exploitation of specific problem knowledge as one of their central tenets. MAs can take different forms although a classical incarnation involves the integration of independent search processes within a population‐based optimization approach. We discuss this basic structure as well as several of the issues arising in the design process. This paves the way for providing a glimpse of some algorithmic extensions of this basic scheme. After providing an overview of the numerous practical applications of MAs, we close this article with some current perspectives of these techniques.
Pillar[
n
]arenes: Synthesis, Structure, and Applications
Authors: Ogoshi Tomoki , Kakuta Takahiro , Yamagishi Tada‐aki
Published: November 2016

Pillar[
n
]arenes are macrocyclic compounds composed of 1,4‐dialkoxybenzene units lined in the para‐position. Pillar[
n
]arenes are host molecules of interest not only to supramolecular chemists but also for those working in other fields of chemistry. Compared to other host molecules, their main advantages are facile synthesis, characteristic pillar‐shaped structure, versatile functionality, and unique host–guest properties. In this article, we review these fundamental properties of pillar[
n
]arenes. Their applications such as mechanically interlocked molecules, artificial channels, supramolecular gel materials, porous materials for gas and organic vapor adsorption, surface modification, and supramolecular catalysts are also described.
Cytosolic iron–sulfur cluster transfer—a proposed kinetic pathway for reconstitution of glutaredoxin 3
Authors: Wachnowsky Christine , Fidai Insiya , Cowan James A.
Published: November 2016

Iron–sulfur (Fe–S) clusters are ubiquitously conserved and play essential cellular roles. The mechanism of Fe–S cluster biogenesis involves multiple proteins in a complex pathway. Cluster biosynthesis primarily occurs in the mitochondria, but key Fe–S proteins also exist in the cytosol. One such protein, glutaredoxin 3 (Grx3), is involved in iron regulation, sensing, and mediating [2Fe‐2S] cluster delivery to cytosolic protein targets, but the cluster donor for cytosolic Grx3 has not been elucidated. Herein, we delineate the kinetic transfer of [2Fe‐2S] clusters into Grx3 from potential cytosolic carrier/scaffold proteins, IscU and Nfu, to evaluate a possible model for Grx3 reconstitution in vivo.
Selenoprotein P neutralizes lipopolysaccharide and participates in hepatic cell endoplasmic reticulum stress response
Authors: Zhao Yongzhong , Banerjee Shuvojit , Huang Ping , Wang Xinning , Gladson Candece L. , Heston Warren D. , Foster Charles B.
Published: November 2016

Low serum selenium or selenoprotein P (SePP) levels have been repetitively observed in severe sepsis. The role of SePP in sepsis is incompletely characterized. To test the hypothesis that lipopolysaccharide (LPS) interacts with SePP, we investigated the interaction between LPS and the histidine‐rich (His‐rich) regions of SePP. We demonstrate that both purified SePP and synthetic peptides corresponding to the His‐rich motifs neutralized LPS. In addition, we used a hepatocyte model to study the fate of SePP in response to LPS or endoplasmic reticulum (ER) stress. Our findings indicate that ER stress increases the cellular level of SePP and promotes its nuclear localization.
An allosteric site enables fine‐tuning of cathepsin K by diverse effectors
Authors: Novinec Marko , Rebernik Mateja , Lenarčič Brigita
Published: November 2016

The cysteine peptidase cathepsin K is a potent collagenolytic enzyme and a promising target for the treatment of osteoporosis. Here, we characterize its allosteric fine‐tuning via a recently identified allosteric site. We show that compound NSC94914 binds this site and acts as a specific partial inhibitor of the collagenolytic activity of cathepsin K. We link the functional differences between NSC94914 and known effectors (compound NSC11345 and glycosaminoglycans) to their different modes of interaction with the site. We characterize the allosteric site by site‐directed mutagenesis and show that it is involved in specific regulation of the collagenolytic activity of cathepsin K.
Global atmospheric response to emissions from a proposed reusable space launch system
Authors: Larson Erik J. L. , Portmann Robert W. , Rosenlof Karen H. , Fahey David W. , Daniel John S. , Ross Martin N.
Published: November 2016

Modern reusable launch vehicle technology may allow high flight rate space transportation at low cost. Emissions associated with a hydrogen fueled reusable rocket system are modeled based on the launch requirements of developing a space‐based solar power system that generates present‐day global electric energy demand. Flight rates from 104 to 106 per year are simulated and sustained to a quasisteady state. For the assumed rocket engine, H2O and NOX are the primary emission products; this also includes NOX produced during reentry heating. For a base case of 105 flights per year, global stratospheric and mesospheric water vapor increase by approximately 10 and 100%, respectively. As a result, high‐latitude cloudiness increases in the lower stratosphere and near the mesopause by as much as 20%. Increased water vapor also results in global effective radiative forcing of about 0.03 W/m2. NOX produced during reentry exceeds meteoritic production by more than an order of magnitude, and along with in situ stratospheric emissions, results in a 0.5% loss of the globally averaged ozone column, with column losses in the polar regions exceeding 2%.
Estimating the duration of geologic intervals from a small number of age determinations: A challenge common to petrology and paleobiology
Authors: Glazner Allen F. , Sadler Peter M.
Published: November 2016

The duration of a geologic interval, such as the time over which a given volume of magma accumulated to form a pluton, or the lifespan of a large igneous province, is commonly determined from a relatively small number of geochronologic determinations (e.g., 4–10) within that interval. Such sample sets can underestimate the true length of the interval by a significant amount. For example, the average interval determined from a sample of size
 = 5, drawn from a uniform random distribution, will underestimate the true interval by 50%. Even for
 = 10, the average sample only captures ∼80% of the interval. If the underlying distribution is known then a correction factor can be determined from theory or Monte Carlo analysis; for a uniform random distribution, this factor is
. Systematic undersampling of interval lengths can have a large effect on calculated magma fluxes in plutonic systems. The problem is analogous to determining the duration of an extinct species from its fossil occurrences. Confidence interval statistics developed for species origination and extinction times are applicable to the onset and cessation of magmatic events.
Cenozoic epeirogeny of the Indian peninsula
Authors: Richards F. D. , Hoggard M. J. , White N. J.
Published: November 2016

Peninsular India is a cratonic region with asymmetric relief manifest by eastward tilting from the 1.5 km high Western Ghats escarpment toward the floodplains of eastward‐draining rivers. Oceanic residual depth measurements on either side of India show that this west‐east asymmetry is broader scale, occurring over distances of > 2000 km. Admittance analysis of free‐air gravity and topography shows that the elastic thickness is 10 ± 3 km, suggesting that regional uplift is not solely caused by flexural loading. To investigate how Indian physiography is generated, we have jointly inverted 530 river profiles to determine rock uplift rate as a function of space and time. Key erosional parameters are calibrated using independent geologic constraints (e.g., emergent marine deposits, elevated paleosurfaces, uplifted lignite deposits). Our results suggest that regional tilt grew at rates of up to 0.1 mm a−1 between 25 Ma and the present day. Neogene uplift initiated in the south and propagated northward along the western margin. This calculated history is corroborated by low‐temperature thermochronologic observations, by sedimentary flux of clastic deposits into the Krishna‐Godavari delta, and by sequence stratigraphic architecture along adjacent rifted margins. Onset of regional uplift predates intensification of the Indian monsoon at 8 Ma, suggesting that rock uplift rather than climatic change is responsible for modern‐day relief. A positive correlation between residual depth measurements and shear wave velocities beneath the lithosphere suggests that regional uplift is generated and maintained by temperature anomalies of ±100 °C within a 200 ± 25 km thick asthenospheric channel.
Trace element and Sr isotope records of multi‐episode carbonatite metasomatism on the eastern margin of the North China Craton
Authors: Deng Lixu , Liu Yongsheng , Zong Keqing , Zhu Lüyun , Xu Rong , Hu Zhaochu , Gao Shan
Published: November 2016

Lherzolite xenoliths entrained in the Changle Cenozoic basalts were analyzed to infer mantle process beneath the eastern block of the North China Craton. These xenoliths were classified into two types. Clinopyroxenes (Cpx) in the type‐1 xenoliths are strongly enriched in large ion lithophile elements and light rare earth elements (LREE) but depleted in high field‐strength elements and heavy rare earth elements, and show high Ca/Al, Zr/Hf, and (La/Yb)N ratios but low Ti/Eu ratios. These features indicate that they were crystallized from a carbonatitic melt. Cpx in the type‐2 xenoliths are mostly characterized by a chemical zonation, that is, LREE and Sr contents and (La/Yb)N and Eu/Ti ratios gradually increase from the cores to the rims. Some fresh cores preserve the original signatures of the depleted mantle. These observations indicate partial modification of pre‐existing Cpx by carbonatite metasomatism. Two episodes of metasomatism were identified based on Sr isotopic compositions of Cpx and carbonate inclusions within olivines. Both the carbonate inclusions and Cpx cores in the type‐2 xenoliths have relatively high 87Sr/86Sr ratios (>0.7033), suggesting metasomatism due to CO2‐rich silicate melt derived from the recycled oceanic crust. However, low 87Sr/86Sr ratios of Cpx rims in the type‐2 xenoliths suggest a late stage of metasomatism by a low‐87Sr/86Sr carbonatitic melt (<0.7024), which might have been caused by upwelling of the asthenosphere mantle. Such multiple metasomatism could have played an important role in changing the chemical composition of mantle from refractory and depleted to fertile and enriched.
Wetland shoreline recession in the Mississippi River Delta from petroleum oiling and cyclonic storms
Authors: Rangoonwala Amina , Jones Cathleen E. , Ramsey Elijah
Published: November 2016

We evaluate the relative impact of petroleum spill and storm surge on near‐shore wetland loss by quantifying the lateral movement of coastal shores in upper Barataria Bay, Louisiana (USA), between June 2009 and October 2012, a study period that extends from the year prior to the Deepwater Horizon spill to 2.5 years following the spill. We document a distinctly different pattern of shoreline loss in the 2 years following the spill, both from that observed in the year prior to the spill, during which there was no major cyclonic storm, and from change related to Hurricane Isaac, which made landfall in August 2012. Shoreline erosion following oiling was far more spatially extensive and included loss in areas protected from wave‐induced erosion. We conclude that petroleum exposure can substantially increase shoreline recession particularly in areas protected from storm‐induced degradation and disproportionally alters small oil‐exposed barrier islands relative to natural erosion.
Geophysical imaging of shallow degassing in a Yellowstone hydrothermal system
Authors: Pasquet S. , Holbrook W. S. , Carr B. J. , Sims K. W. W.
Published: November 2016

The Yellowstone Plateau Volcanic Field, which hosts over 10,000 thermal features, is the world's largest active continental hydrothermal system, yet very little is known about the shallow “plumbing” system connecting hydrothermal reservoirs to surface features. Here we present the results of geophysical investigations of shallow hydrothermal degassing in Yellowstone. We measured electrical resistivity, compressional‐wave velocity from refraction data, and shear wave velocity from surface‐wave analysis to image shallow hydrothermal degassing to depths of 15–30 m. We find that resistivity helps identify fluid pathways and that Poisson's ratio shows good sensitivity to saturation variations, highlighting gas‐saturated areas and the local water table. Porosity and saturation predicted from rock physics modeling provide critical insight to estimate the fluid phase separation depth and understand the structure of hydrothermal systems. Finally, our results show that Poisson's ratio can effectively discriminate gas‐ from water‐saturated zones in hydrothermal systems.
ENSO modulation of tropical Indian Ocean subseasonal variability
Authors: Jung Eunsil , Kirtman Ben P.
Published: November 2016

In this study, we use 30 years of retrospective climate model forecasts and observational estimates to show that El Niño/Southern Oscillation (ENSO) affects the amplitude of subseasonal variability of sea surface temperature (SST) in the southwest Indian Ocean, an important Tropical Intraseasonal Oscillation (TISO) onset region. The analysis shows that deeper background mixed‐layer depths and warmer upper ocean conditions during El Niño reduce the amplitude of the subseasonal SST variability over Seychelles‐Chagos Thermocline Ridge (SCTR), which may reduce SST‐wind coupling and the amplitude of TISO variability. The opposite holds for La Niña where the shallower mixed‐layer depth enhances SST variability over SCTR, which may increase SST‐wind coupling and the amplitude of TISO variability.
Aridity over a semiarid zone in northern China and responses to the East Asian summer monsoon
Authors: Zhang Hongli , Zhang Qiang , Yue Ping , Zhang Liang , Liu Qian , Qiao Shaobo , Yan Pengcheng
Published: November 2016

In this study, the variability of the aridity over a semiarid zone in Northern China from 1961 to 2013 and its association with the northernmost margin of the East Asian summer monsoon (EASM) and its intensity were investigated using composite analysis, correlative analysis, and unrotated and rotated empirical orthogonal function analyses. The results indicate that a nonsignificant drying trend (0.03/10 years) occurs over the entire eastern semiarid zone, accompanied by a southward retreat in the northernmost margin of the EASM (0.24°/10 years), and that drying (0.11/10 years) and southward retreat (0.28°/10 years) are most obvious on the Loess Plateau. The response of the annual variation of aridity to changes in the northernmost margin of the EASM is also compared with its responses to changes in the intensity of the EASM; the results indicate that it is more related to the former, especially over the Loess Plateau. Furthermore, an abnormal aridity event is likely to occur over the Loess Plateau in a year when the EASM margin advances to its northernmost latitude abnormally ahead of time and retreats abnormally ahead of time compared to the mean state.
A critical evaluation of modeled solar irradiance over California for hydrologic and land surface modeling
Authors: Lapo Karl E. , Hinkelman Laura M. , Sumargo Edwin , Hughes Mimi , Lundquist Jessica D.
Published: November 2016

Studies of land surface processes in complex terrain often require estimates of meteorological variables, i.e., the incoming solar irradiance (Qsi), to force land surface models. However, estimates of Qsi are rarely evaluated within mountainous environments. We evaluated four methods of estimating Qsi: the CERES Synoptic Radiative Fluxes and Clouds (SYN) product, MTCLIM, a regional reanalysis product derived from a long‐term Weather Research and Forecast simulation, and Mountain Microclimate Simulation Model (MTCLIM). These products are evaluated over the Central Valley and Sierra Nevada mountains in California, a region with meteorology strongly impacted by complex topography. We used a spatially dense network of Qsi observations (n = 70) to characterize the spatial characteristics of Qsi uncertainty. Observation sites were grouped into five subregions, and Qsi estimates were evaluated against observations in each subregion. Large monthly biases (up to 80 W m−2) outside the observational uncertainty were found for all estimates in all subregions examined, typically reaching a maximum in the spring. We found that MTCLIM and SYN generally perform the best across all subregions. Differences between Qsi estimates were largest over the Sierra Nevada, with seasonal differences exceeding 50 W m−2. Disagreements in Qsi were especially pronounced when averaging over high‐elevation basins, with monthly differences up to 80 W m−2. Biases in estimated Qsi predominantly occurred with darker than normal conditions associated with precipitation (a proxy for cloud cover), while the presence of aerosols and water vapor was unable to explain the biases. Users of Qsi estimates in regions of complex topography, especially those estimating Qsi to force land surface models, need to be aware of this source of uncertainty.
A global model of tropospheric chlorine chemistry: Organic versus inorganic sources and impact on methane oxidation
Authors: Hossaini Ryan , Chipperfield Martyn P. , Saiz‐Lopez Alfonso , Fernandez Rafael , Monks Sarah , Feng Wuhu , Brauer Peter , von Glasow Roland
Published: November 2016

Chlorine atoms (Cl) are highly reactive toward hydrocarbons in the Earth's troposphere, including the greenhouse gas methane (CH4). However, the regional and global CH4 sink from Cl is poorly quantified as tropospheric Cl concentrations ([Cl]) are uncertain by ~2 orders of magnitude. Here we describe the addition of a detailed tropospheric chlorine scheme to the TOMCAT chemical transport model. The model includes several sources of tropospheric inorganic chlorine (Cly), including (i) the oxidation of chlorocarbons of natural (CH3Cl, CHBr2Cl, CH2BrCl, and CHBrCl2) and anthropogenic (CH2Cl2, CHCl3, C2Cl4, C2HCl3, and CH2ClCH2Cl) origin and (ii) sea‐salt aerosol dechlorination. Simulations were performed to quantify tropospheric [Cl], with a focus on the marine boundary layer, and quantify the global significance of Cl atom CH4 oxidation. In agreement with observations, simulated surface levels of hydrogen chloride (HCl), the most abundant Cly reservoir, reach several parts per billion (ppb) over polluted coastal/continental regions, with sub‐ppb levels typical in more remote regions. Modeled annual mean surface [Cl] exhibits large spatial variability with the largest levels, typically in the range of 1–5 × 104 atoms cm−3, in the polluted northern hemisphere. Chlorocarbon oxidation provides a tropospheric Cly source of up to ~4320 Gg Cl/yr, sustaining a background surface [Cl] of <0.1 to 0.5 × 103 atoms cm−3 over large areas. Globally, we estimate a tropospheric methane sink of ~12–13 Tg CH4/yr due the CH4 + Cl reaction (~2.5% of total CH4 oxidation). Larger regional effects are predicted, with Cl accounting for ~10 to >20% of total boundary layer CH4 oxidation in some locations.
The uptake of HO2 on meteoric smoke analogues
Authors: James Alexander D. , Moon Daniel R. , Feng Wuhu , Lakey Pascale S. J. , Frankland Victoria L. , Heard Dwayne E. , Plane John M. C.
Published: November 2016

The kinetics of heterogeneous HO2 uptake onto meteoric smoke particles (MSPs) has been studied in the laboratory using analogues of MSP aerosol entrained into a flow tube. The uptake coefficient, γ, was determined on synthetic amorphous olivine (MgFeSiO4) to be (6.9 ± 1.2) × 10−2 at a relative humidity (RH) of 10%. On forsterite (Mg2SiO4), γ = (4.3 ± 0.4) × 10−3 at RH = 11.6% and (7.3 ± 0.4) × 10−2 at RH = 9.9% on fayalite (Fe2SiO4). These results indicate that Fe plays a more important mechanistic role than Mg in the removal of HO2 from the gas phase. Electronic structure calculations show that Fe atoms exposed at the particle surface provide a catalytic site where HO2 is converted to H2O2 via an Eley‐Rideal mechanism, but this does not occur on exposed surface Mg atoms. The impact of this heterogeneous process in the middle atmosphere was then investigated using a whole atmosphere chemistry‐climate model which incorporates a microphysical treatment of MSPs. Using a global MSP production rate from meteoric ablation of 44 t/day, heterogeneous uptake (with γ = 0.2) on MSPs significantly alters the HOx budget in the nighttime polar vortex. This impact is highly latitude dependent and thus could not be confirmed using currently available satellite measurements of HO2, which are largely unavailable at latitudes greater than 70°.
Estimation of three‐phase relative permeability by simulating fluid dynamics directly on rock‐microstructure images
Authors: Jiang F. , Tsuji T.
Published: November 2016

Given the world's growing demand for energy, a combination of geological CO2 sequestration and enhanced oil recovery (EOR) technologies is currently regarded as a promising solution, as it would provide a means of reducing carbon emissions into the atmosphere while also leading to the economic benefit of simultaneously recovering oil. The optimization of injection strategies to maximize CO2 storage and increase the oil recovery factors requires complicated pore‐scale flow information within a reservoir system consisting of coexisting oil, water, and CO2 phases. In this study, an immiscible three‐phase lattice‐Boltzmann (LB) model was developed to investigate the complicated flow state with interaction between water, oil, and CO2 systems in porous media. The two main mechanisms of oil remobilization, namely, double‐drainage and film flow, can be captured by our model. The estimation of three‐phase relative permeability is proposed using the digital rock physics (DRP) simulations. The results indicate that the relative permeability of CO2 as calculated using our steady state method is not sensitive to the initial oil fraction if the oil distribution is originally uniform. Baker's (1988) empirical model was tested and found to be able to provide a good prediction of the three‐phase relative permeability data. Our numerical method provides a new tool for accurately predicting three‐phase relative permeability data directly based on micro‐CT rock images.
Plant Responses to Freezing
Authors: Fujikawa Seizo
Published: November 2016

During the course of evolution, plants have developed complex mechanisms to survive under a freezing condition. The ability of temperate plants to endure freezing differs depending on the season and depending on the region they inhabit in relation to the environmental temperatures. The prerequisite for survival of plants under a freezing condition is avoidance of lethal intracellular freezing in living cells. Depending on the function in living cells, such avoidance mechanisms change due to the difference in responses of cell walls as well as the plasma membrane to extracellular ice. Owing to these differences, living plant cells adapt to freezing by extracellular freezing and deep supercooling and also by extraorgan freezing, in which cells adapt by an intermediate form between extracellular freezing and deep supercooling.

Key Concepts

The first step of freezing resistance is the blocking of cell walls and plasma membranes against inoculation of extracellular ice.

Living cells in most temperate plant tissues respond to freezing by extracellular freezing, in which cell walls inhibit ice penetration but allow dehydration.

Interbilayer events, which are caused by the close approach of membranes by mechanical stress of freezing, are the main cause of injury by extracellular freezing.

Many cold acclimation‐induced changes are related to inhibition of or reduction in the incidence of interbilayer events.

Adaptation by deep supercooling occurs in cells with rigid and thick walls, which do not allow penetration of ice or dehydration.

Supercooling capacity is changed by intracellular contents, especially by the interaction of antiice nucleation polyphenols with ice nucleators.

Dormant buds of many woody plants respond to freezing by extraorgan freezing, in which formation of extracellular ice is excluded in tissues with freezing‐susceptible cells.
Communications, Radar, and Wireless Sensor Networks, Detection in
Authors: Varshney Pramod K. , Viswanathan Ramanarayanan
Published: November 2016

Detection of signals in noise arises in a number of engineering applications. Here, we restrict our attention to three applications within electrical engineering, namely, communications, radar signal processing, and wireless sensor networks. We first formulate signal detection problems in a general framework and then discuss them in the context of the three applications. Because of space limitations, the topics have been selected to provide a broader exposure to this field. Many references have been provided for additional insights.
Operations Research, Simulation
Authors: Sharkey Phoebe D.
Published: November 2016

Simulation models have been indispensable tools for decision makers in many different public and private environments. Simulation models are created in order to provide valuable insight to decision makers by replicating real‐life decision scenarios and exploring more complete information about the relative uncertainties and their impacts in those environments. This article discusses the methodology of developing a simulation model that involves the abstraction of a real‐life system into a symbolic model format. The multiple stages required in a Monte Carlo simulation study include the (i) problem statement definition; (ii) information gathering and data preparation; (iii) model conceptualization; (iv) model implementation; (v) analysis and interpretation; (vi) verification and validation; and (vii) implementation and documentation. Once a model has been verified and validated as accurately representing the real‐world environment, many “What if” questions about the system can be posed. Illustrative examples are presented.
Dynamic Allocation Index
Authors: Gittins John C.
Published: November 2016

Given a constant stream of some resource and a set of projects each of which generates a stochastic reward stream when the resource stream is allocated to it, the question arises of how to adaptively allocate the resource stream between the projects so as to maximize the overall payoff. The dynamic allocation (or Gittins) index for a project is a function defined on the state space of the project for which under exponential discounting the overall payoff is maximized by a policy of allocating the resource stream at each decision time to the project for which the index value is currently the largest. This article discusses the uses and calculation of these indices and the optimality of index‐based policies.
Spatial Analysis in Ecology
Authors: Fortin Marie‐Josée , Dale Mark R.T. , Ver Hoef Jay M.
Published: November 2016

The first step in understanding ecological processes is to identify their spatial patterns. Ecological data are usually characterized by spatial structures and as such, they are said to be spatially autocorrelated.
Spatial autocorrelation
refers to the pattern where the values of a quantitative variable are more similar at nearby locations than expected by chance alone. Most ecological data exhibit some degree of spatial autocorrelation that is modulated by the spatial sampling design used to record the data and the method used to analyze them. Furthermore, ecological data can be the end result of several processes operating at different spatial scales. In such cases, ecological data are a composite of large‐scale trends at the macroscale, gradients and patchiness at mesoscale, and random patterns at local and microscales. Hence, to estimate the magnitude and the extent of spatial autocorrelation, various spatial statistics can be used. Here, we review the spatial statistics most commonly used by ecologists.
Mixed‐Mode Surveys
Authors: Klausch Thomas , Schouten Barry
Published: November 2016

Surveys can be conducted with a variety of survey modes. Over the past decade, and following the emergence of the Web, many surveys have moved to designs in which multiple modes are combined, the so‐called mixed‐mode surveys. The contemporary modes are telephone, face‐to‐face, mail/paper, and online through various devices (desktop/laptop, tablet, and smartphone). Survey modes affect all errors known to reduce the accuracy of survey statistics. An extensive literature has been developed around mode comparisons and multimode survey design and estimation. In the article, the impact of the choice of modes on survey error is discussed and methodology is presented to reduce method effects that result from the choice of modes.
Informative Cluster Size
Authors: Williamson John M.
Published: November 2016

Correlated outcomes are collected in many areas of research and occur for a variety of reasons. Valid inference is reliant upon properly accounting for the correlation among outcomes within subjects. Analysis should also consider informative cluster size, which occurs when cluster size is related to the outcome of interest and is common in studies with periodontal, surgical outcome, and reproductive toxicology data, among others. Such methods of analysis are increasingly available.
Project Management in the Oil & Gas Industry – ABayesian Approach
Authors: Caron Franco , Ruggeri Fabrizio
Published: November 2016

A reliable “estimate at completion” from the early stage of project execution is essential in order to enable efficient and proactive project management. Thenonrepetitiveanduncertainnature of projects and the involvement ofmultiple stakeholdersrequire the use and integration of multiple informative sources in order to provide accurate forecasts. Moreover, in the Oil & Gas industry, projects are characterized by a high level of complexity and financial impact.

The article aims at multiple objectives such as introducing the need for the identification and utilization of all the available knowledge in order to improve the forecasting process; developing a Bayesian approach in order to integrate the diverse knowledge sources; exploring the integration of data records and experts' judgment related to the ongoing project; exploring the integration of data records related to projects completed in the past and to the ongoing project; and finally developing a Bayesian model capable of using three different knowledge sources, data records and experts' judgments related to the ongoing project and data records related to similar projects completed in the past.

The model has been tested in a set of large and complex projects in the Oil & Gas industry, in order to forecast the final duration and the final cost. The results show a higher forecasting accuracy of the Bayesian model compared to the traditional earned value management (EVM) methodology.
Optimal Dynamic Treatment Regimes
Authors: Davidian Marie , Tsiatis Anastasios A. , Laber Eric B.
Published: November 2016

A dynamic treatment regime is a set of sequential decision rules, each corresponding to a key decision point in a disease or disorder process that dictates the next treatment for a patient based on accrued information on the patient. An optimal dynamic treatment regime is a regime that leads to the most favorable outcome on average if used to select treatment for the entire patient population. This entry reviews a statistical framework in which an optimal dynamic treatment regime can be defined precisely and methods by which it can be estimated from data under appropriate assumptions.
Noninferiority Margin and Other Methodological Issues in Designing Noninferiority Trials: A Review
Authors: Gupta Sandeep Kumar
Published: November 2016

Noninferiority clinical trials help in detecting a new treatment that have roughly the same effectiveness, yet may offer different advantages. Thus, noninferiority trials can be used in a situation when a new treatment has almost the same effectiveness as its comparator but may offer other advantages over the existing drug such as a novel method of administration or a better safety profile. Some argue that noninferiority trials only benefit pharmaceutical companies as they permit medicines without any added effectiveness to get marketing authorization. There are many basic differences between noninferiority and superiority trials. Noninferiority clinical trials aim to prove that the test product is not unreasonably inferior, or “noninferior” than the comparator by more than a prestipulated margin. From a methodological perspective, compared to superiority trials, noninferiority trials have methodological issues in design and analysis that can influence proper inference and also noninferiority trials are a source of great dispute. One of the pivotal but arduous steps in planning noninferiority trial is itemizing a noninferiority margin: a prelude below which it can be accepted that the experimental drug is not worse than its comparator.
Degenerative Ataxias: challenges in clinical research
Authors: Subramony Sub H.
Published: November 2016

The degenerative ataxias are a very heterogeneous group of disorders that include numerous genetic diseases as well as apparently “sporadic” entities. There has been an explosion of discoveries related to genetic defects and related pathomechanisms that has brought us to the threshold of meaningful therapies in some but not all of these diseases. There also continues to be lack of knowledge of the causation of disease in a sizeable proportion of these patients. The overall rarity of ataxias as a whole and certainly of the individual genetic entities together with slow and variable progression and variable prognosis in juxtaposition with a rapid development of possible therapies in the horizon such as gene replacement and gene knock‐down strategies places the ataxias in a unique position distinct from other similar neurodegenerative diseases. The pace of laboratory research seems not matched by the pace of clinical research and clinical trial readiness. This review summarizes the author's views on the various challenges in translational research in ataxias and hopes to stimulate further thought and discussions on how to bring real help to these patients.
Experimental and Theoretical Assessment of Ni‐Based Binary Compounds for the Hydrogen Evolution Reaction
Authors: Ledendecker Marc , Schlott Hannah , Antonietti Markus , Meyer Bernd , Shalom Menny
Published: November 2016

Metallic binary compounds have emerged in recent years as highly active and stable electrocatalysts toward the hydrogen evolution reaction. In this work, the origin of their high activity from a theoretical and experimental point of view is elucidated. Here, different metallic ceramics as Ni3S2, Ni3N, or Ni5P4 are grown directly on Ni support in order to avoid any contaminations. The correlation of theoretical calculations with detailed material characterization and electrochemical testing paves the way to a deeper understanding of possible active adsorption sites for each material and the observed catalytic activity. It is shown that heteroatoms as P, S, and N actively take part in the reaction and do not act as simple spectator. Due to the anisotropic nature of the materials, a variety of adsorption sites with highly coverage‐dependent properties exists, leading to a general shift in hydrogen adsorption free energies ΔGH close to zero. Extending the knowledge gained about the here described materials, a new catalyst is prepared by modifying a high surface Ni foam, for which current densities up to 100 mA cm−2 at around 0.15 V (for Ni3N) are obtained.
Hydrodynamic drift ratchet scalability
Authors: Herringer James W. , Lester Daniel R. , Dorrington Graham E. , Rosengarten Gary , Mitchell James G.
Published: November 2016

The hydrodynamic drift ratchet provides a novel means to continuously separate particles at the microscale, based on particle size. Separation arises from a combination of diffusion and particle‐wall hydrodynamic interactions. As there are currently no verified experiments, our aim is to determine numerically how these systems scale so that appropriate experiments can be designed. Using nondimensional variables, we derive the correct scaling parameters governing drift ratchets by simulating individual particle motion using a model that treats the particle dynamics at pore walls as elastic reflections. While our model does not quantitatively resolve the detailed hydrodynamic interactions, we show that it does recover the correct scaling behavior for these interactions. Our simulations demonstrate that the drift velocity relative to the characteristic pore size is independent of pore size if all the relevant nondimensional groups remain constant. Dynamic similarity can be used to facilitate the appropriate design and testing protocols for experiments. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2358–2366, 2017
A novel preparation method of polyaluminum chloride/polyacrylamide composite coagulant: Composition and characteristic
Authors: Wang Xiaoping , Tang Xiaomin , Feng Ping , Li Xinyu , Zhao Chuanliang , Chen Wei , Zheng Huaili
Published: November 2016

Inorganic/organic composite coagulants have drawn a wide attention through the years owing to its superior coagulation behaviors. In this study, polyaluminum chloride (PAC)/polyacrylamide (PAM) composite coagulant was synthesized by ultraviolet (UV) irradiation by using PAC and acrylamide (AM) as raw materials, urea as a solubilizer, and 2,2′‐Azobis[2‐(2‐imidazolin‐2‐yl)propane]dihydrochloride (VA‐044) as an initiator. The effect of total monomer mass fraction, solubilizer dosage and initiator dosage on the viscosity and molecular weight of PAC/PAM composite coagulant was discussed. The results suggest that the composite coagulant with high polymerization degree, intrinsic viscosity of 1483 mL/g and molecular weight of 7.38 million, could be obtained when the total monomer mass fraction of 40%, urea dosage of 1.5% and initiator dosage of 0.6% are chosen in the preparation. It is a potential preparation method of composite coagulant with short preparation time and high preparation efficiency. Fourier transform infrared spectrum and 1H nuclear magnetic resonance spectroscopy represent that the coagulant for polyaluminum chloride and polypropylene are copolymer. Thermal gravimetric analysis describes the high thermal stability of composite coagulant. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44500.
Bounded‐Input Control of the Quadrotor Unmanned Aerial Vehicle: A Vision‐Based Approach
Authors: Asl Hamed Jabbari , Yoon Jungwon
Published: November 2016

In this paper, a bounded‐input controller is designed for the quadrotor vertical take‐off and landing unmanned aerial vehicle (UAV). Visual information is used to localize the aircraft with respect to its environment and an image‐based visual servo scheme is developed to navigate the motion of it. The visual features are selected from perspective image moments and projected on a rotated image plane, which simplifies the controller design. The flow of the features is used as the linear velocity information, and the controller assumes angular velocity and attitude information available for feedback. To design the controller, the dynamics of the quadrotor are decoupled into two parts: translational dynamics and rotational dynamics. First visual data are used to design a bounded‐input controller for the translational dynamics, and then a saturated controller is designed for the rotational dynamics. The boundedness of the controller increases the chance of keeping the visual features in the field of view of the camera. Furthermore, the controllers also cope with the unknown depth of the image, and the external disturbances. The complete stability analysis of the overall system is presented to show that all states are bounded and the error signals converge to zero asymptotically. Simulation examples are provided in both nominal and perturbed conditions which show the effectiveness of the proposed theoretical results.
An efficient orange–red‐emitting LiNa3P2O7:Sm3+ pyrophosphate: Structural and optical analysis for solid‐state lighting
Authors: Dillip G.R. , Munirathnam K. , Raju B. Deva Prasad , Sushma N. John , Joo S.W.
Published: November 2016

A trivalent rare‐earth ion (Sm3+)‐doped LiNa3P2O7 (LNPO) phosphor was synthesized using a conventional high‐temperature solid‐state reaction route. A predominant orthorhombic phase of LNPO was observed in all X‐ray diffraction patterns. The surface states of the LNPO:Sm phosphor were confirmed by X‐ray photoelectron spectroscopy. Under 401 nm excitation, the Sm‐doped LNPO phosphors showed sharp emission peaks at 563, 600 and 647 nm that are related to the f–f transition of Sm3+ ions. The optimum concentration of Sm3+ (9 mol%) produced Commission Internationale de l'Eclairage chromaticity coordinates, color rendering index and correlated color temperature of (0.564, 0.434), 42 and 1843 K, respectively.
Substrate specificity of an actively assembling amyloid catalyst
Authors: Heier Jason L. , Mikolajczak Dorian J. , Böttcher Christoph , Koksch Beate
Published: November 2016

In the presence of Zn2+, the catalytic, amyloid‐forming peptide Ac‐IHIHIQI‐NH2, was found to exhibit enhanced selectivity for hydrophobic p‐nitrophenyl ester substrates while in the process of self‐assembly. As opposed to the substrate p‐nitrophenyl acetate, which was more effectively hydrolyzed with Ac‐IHIHIQI‐NH2 in its fully fibrillar state, the hydrophobic substrate Z‐L‐Phe‐ONp was converted with a second‐order rate constant more than 11‐times greater when the catalyst was actively assembling. Under such conditions, Z‐L‐Phe‐ONp hydrolysis proceeded at a greater velocity than the more hydrophilic and otherwise more labile ester Boc‐L‐Asn‐ONp. When assembling, the catalyst also showed increased selectivity for the L‐enantiomer of Z‐Phe‐ONp. These findings suggest the occurrence of increased interactions of hydrophobic moieties of the substrate with exposed hydrophobic surfaces of the assembling peptides and present valuable features for future de novo design consideration.
Development of a targeted method for quantification of gypenoside XLIX in rat plasma, using SPE and LC–MS/MS
Authors: Guo Song , Sui Chengxu , Ma Ying
Published: November 2016

A sensitive, selective and rapid liquid chromatography–tandem mass spectrometry (LC–MS/MS) method was developed for the quantification of gypenoside XLIX, a naturally occurring gypenoside of Gynostemma pentaphyllum in rat plasma and then validated according to the US Food and Drug Administration's Guidance for Industry: Bioanalytical Method Validation. Plasma samples were prepared by a simple solid‐phase extraction. Separation was performed on a Waters XBridgeTM BEH C18 chromatography column (4.6 × 50 mm, 2.5 μm) using a mobile phase of acetonitrile and water (62.5:37.5, v/v). Gypenoside XLIX and the internal standard gypenoside A were detected in the negative ion mode using selection reaction monitoring of the transitions at m/z 1045.6 → 913.5 and 897.5 → 765.4, respectively. The calibration curve was linear (R2 > 0.990) over a concentration range of 10–7500 ng/mL with the lower quantification limit of 10 ng/mL. Intra‐ and inter‐day precision was within 8.6% and accuracy was ≤10.2%. Stability results proved that gypenoside XLIX and the IS remained stable throughout the analytical procedure. The validated LC–MS/MS method was then applied to analyze the pharmacokinetics of gypenoside XLIX after intravenous administration to rats (1.0, 2.0 and 4.0 mg/kg).