bluuebunny/crossref_metadata_2025 huggingface dataset:
The shape of patterns to come: from initial formation to long‐term evolution
Authors: Murray A. Brad , Goldstein Evan B. , Coco Giovanni
Published: October 2013

Many studies focus on the emergence and development of rhythmic landscape patterns. In this contribution we explore the different behaviors found as patterns evolve; the trajectories that patterns exhibit as they transit from infinitesimal‐amplitude perturbation to a statistically steady state (or in some cases to continued statistical evolution). The variety of behaviors observed, either through field and laboratory experiments or numerical modeling, can be reduced to four classes: (a) simple stabilization where predictions based on the initial growth of small perturbations corresponds with the characteristics of patterns observed in nature; (b) significant pattern coarsening en route to saturated wavelength, where non‐linear interactions between finite‐amplitude pattern elements change the geometric properties of a pattern as it approaches steady‐state; (c) perpetual coarsening where the wavelength associated with the emerging pattern continues to grow over time and is only limited by physical boundaries or external constrains; (d) slow evolution toward a different attractor, a novel behavior observed in numerical modeling that involves profound temporal changes in pattern characteristics. Within these classes we also observe generalizable non‐linear behaviors: dependence on initial conditions, the emergence of pattern‐scale variables such as pattern defects, and the presence of multiple stable states. Predicting the shape of patterns to come remains a challenge – one that we suggest requires a range of modeling approaches to address both initial instabilities and the emergent properties of evolving patterns, which involve disparate forms of non‐linear interactions. Consideration of generic system behaviors at the pattern scale could enhance future pattern formation studies, facilitating appropriate pairings of analysis approaches and pattern‐evolution modes. Copyright © 2013 John Wiley & Sons, Ltd.
Modeling the effects of pulsed versus chronic sand inputs on salmonid spawning habitat in a low‐gradient gravel‐bed river
Authors: Maturana Oscar , Tonina Daniele , McKean James A. , Buffington John M. , Luce Charles H. , Caamaño Diego
Published: October 2013

It is widely recognized that high supplies of fine sediment, largely sand, can negatively impact the aquatic habitat quality of gravel‐bed rivers, but effects of the style of input (chronic vs. pulsed) have not been examined quantitatively. We hypothesize that a continuous (i.e. chronic) supply of sand will be more detrimental to the quality of aquatic habitat than an instantaneous sand pulse equal to the integrated volume of the chronic supply. We investigate this issue by applying a two‐dimensional numerical model to a 1 km long reach of prime salmonid spawning habitat in central Idaho. Results show that in both supply scenarios, sand moves through the study reach as bed load, and that both the movement and depth of sand on the streambed mirrors the hydrograph of this snowmelt‐dominated river. Predictions indicate greater and more persistent mortality of salmonid embryos under chronic supplies than pulse inputs, supporting our hypothesis. However, predicted mortality varies both with salmonid species and location of spawning. We found that the greatest impacts occur closer to the location of the sand input under both supply scenarios. Results also suggest that reach‐scale morphology may modulate the impact of sand loads, and that under conditions of high sand loading climate‐related increases in flow magnitude could increase embryo mortality through sand deposition, rather than streambed scour. Copyright © 2013 John Wiley & Sons, Ltd.
Terrestrial laser scanning of rock slope instabilities
Authors: Abellán Antonio , Oppikofer Thierry , Jaboyedoff Michel , Rosser Nicholas J. , Lim Michael , Lato Matthew J.
Published: October 2013

This manuscript presents a review on the application of a remote sensing technique (terrestrial laser scanning, TLS) to a well‐known topic (rock slope characterization and monitoring). Although the number of publications on the use of TLS in rock slope studies has rapidly increased in the last 5–10 years, little effort has been made to review the key developments, establish a code of best practice and unify future research approaches. The acquisition of dense 3D terrain information with high accuracy, high data acquisition speed and increasingly efficient post‐processing workflows is helping to better quantify key parameters of rock slope instabilities across spatial and temporal scales ranging from cubic decimetres to millions of cubic metres and from hours to years, respectively. Key insights into the use of TLS in rock slope investigations include: (a) the capability of remotely obtaining the orientation of slope discontinuities, which constitutes a great step forward in rock mechanics; (b) the possibility to monitor rock slopes which allows not only the accurate quantification of rockfall rates across wide areas but also the spatio‐temporal modelling of rock slope deformation with an unprecedented level of detail. Studying rock slopes using TLS presents a series of key challenges, from accounting for the fractal character of rock surface to detecting the precursory deformation that may help in the future prediction of rock failures. Further investigation on the development of new algorithms for point cloud filtering, segmentation, feature extraction, deformation tracking and change detection will significantly improve our understanding on how rock slopes behave and evolve. Perspectives include the use of new 3D sensing devices and the adaptation of techniques and methods recently developed in other disciplines as robotics and 3D computer‐vision to rock slope instabilities research. Copyright © 2013 John Wiley & Sons, Ltd.
Biotransformation pathways of fluorotelomer-based polyfluoroalkyl substances: A review
Authors: Butt Craig M. , Muir Derek C.G. , Mabury Scott A.
Published: October 2013

The study reviews the current state of knowledge regarding the biotransformation of fluorotelomer-based compounds, with a focus on compounds that ultimately degrade to form perfluoroalkyl carboxylates (PFCAs). Most metabolism studies have been performed with either microbial systems or rats and mice, and comparatively few studies have used fish models. Furthermore, biotransformation studies thus far have predominately used the 8:2 fluorotelomer alcohol (FTOH) as the substrate. However, there have been an increasing number of studies investigating 6:2 FTOH biotransformation as a result of industry's transition to shorter-chain fluorotelomer chemistry. Studies with the 8:2 FTOH metabolism universally show the formation of perfluorooctanoate (PFOA) and, to a smaller fraction, perfluorononanoate (PFNA) and lower-chain-length PFCAs. In general, the overall yield of PFOA is low, presumably because of the multiple branches in the biotransformation pathways, including conjugation reactions in animal systems. There have been a few studies of non-FTOH biotransformation, which include polyfluoroalkyl phosphates (PAPs), 8:2 fluorotelomer acrylate (8:2 FTAC), and fluorotelomer carboxylates (FTCAs, FTUCAs). The PAPs compounds and 8:2 FTAC were shown to be direct precursors to FTOHs and thus follow similar degradation pathways. Environ Toxicol Chem 2014;33:243–267. © 2013 SETAC
Effect of gold nanoparticles and ciprofloxacin on microbial catabolism: a community-based approach
Authors: Weber Kela P. , Petersen Elijah J. , Bissegger Sonja , Koch Iris , Zhang Jun , Reimer Kenneth J. , Rehmann Lars , Slawson Robin M. , Legge Raymond L. , O'Carroll Denis M.
Published: October 2013

The effect of gold nanoparticles (AuNPs) and ciprofloxacin on the catabolism of microbial communities was assessed. This was accomplished through an ex situ methodology designed to give a priori knowledge on the potential for nanoparticles, or other emerging contaminants, to affect the catabolic capabilities of microbial communities in the environment. Microbial communities from a variety of sources were incubated with 31 prespecified carbon sources and either National Institute of Standards and Technology reference material 10-nm AuNPs or ciprofloxacin on 96-well microtiter plates. From the ciprofloxacin study, dose−response curves were generated and exemplified how this method can be used to assess the effect of a toxicant on overall catabolic capabilities of microbial communities. With 10-nm AuNPs at concentrations ranging from 0.01 µg/mL to 0.5 µg/mL, rhizosphere communities from Typha roots were only slightly catabolically inhibited at a single concentration (0.05 µg/mL); no effects were seen on wetland water communities, and a minor positive (i.e., enhanced catabolic capabilities) effect was observed for loamy soil communities. This positive effect might have been because of a thin layer of citrate found on these AuNPs that initiated cometabolism with some of the carbon sources studied. Under the conditions considered, the possible adverse effects of AuNPs on the catabolic capabilities of microbial communities appears to be minimal. Environ Toxicol Chem 2013;33:44–51. © 2013 SETAC
Avoidance and reproduction tests with the predatory mite Hypoaspis aculeifer: Effects of different chemical substances
Authors: Owojori Olugbenga J. , Waszak Karolina , Roembke Joerg
Published: October 2013

Few toxicity data exist in the literature on the toxicity of chemicals to the predatory mite Hypoaspis aculeifer, but no information is available on its avoidance response. To assess the relevance of the avoidance behavior of H. aculeifer and the relative sensitivity of the mite in comparison with other invertebrates, avoidance and reproduction tests were conducted with 7 chemicals using standardized guidelines. The chemicals (deltamethrin, chloropyrifos, dimethoate, Cu, NaCl, phenanthrene, and boric acid) were selected so as to cover varying chemical classes. For all 3 pesticides tested, avoidance response showed lower sensitivity than reproduction and survival (avoidance median effective concentration [EC50] > reproduction EC50/median lethal concentration [LC50] values). However, for Cu, NaCl, and phenanthrene, the avoidance response showed similar sensitivity as reproduction (avoidance EC50 ≤ reproduction EC50 values), whereas for boric acid, similar sensitivity as survival (avoidance EC50 ≤ LC50 values). Although the mite H. aculeifer appears less sensitive to some of the chemicals tested than most other soil invertebrates, its status as the only predator among organisms for which standardized tests are available affirms its inclusion in routine ecotoxicity assessment. The results of the avoidance test with H. aculeifer suggest its potential usefulness as a rapid screening test for risk assessment purposes. Environ Toxicol Chem 2014;33:230–237. © 2013 SETAC
Design and implementation of distributed load balancing and fast handoff for wireless mesh networks
Authors: Athanasiou George , Tassiulas Leandros
Published: October 2013

The association/handoff procedures are very important towards achieving a balanced operation in 802.11‐based wireless mesh networks. In this paper, we design and implement a cooperative association/handoff scheme, where stations share useful information, and handoff is executed in a seamless manner. Furthermore, we introduce a cross‐layer load balancing mechanism that takes into account uplink and downlink channel conditions, routing performance and congestion control. The proposed heuristic algorithms are inspired by the rapidly designed cooperative protocols and control the communication load of each mesh access point in a distributed manner. We evaluate the performance of our mechanisms through OPNET (www.opnet.com) simulations and testbed experiments. Copyright © 2013 John Wiley & Sons, Ltd.
Reconciling privacy and efficient utility management in smart cities
Authors: Rebollo‐Monedero David , Bartoli Andrea , Hernández‐Serrano Juan , Forné Jordi , Soriano Miguel
Published: October 2013

A key aspect in the design of smart cities is, undoubtedly, a plan for the efficient management of utilities, enabled by technologies such as those entailing smart metering of the residential consumption of electricity, water or gas. While one cannot object to the appealing advantages of smart metering, the privacy risks posed by the submission of frequent, data‐rich measurements cannot simply remain overlooked. The objective of this paper is to provide a general perspective on the contrasting issues of privacy and efficient utility management, by surveying the main requirements and tools, and by establishing exploitable connections. Copyright © 2013 John Wiley & Sons, Ltd.
A simplified model on vertical density profile and shrinkage ratio of virgin and charred medium density fibreboard
Authors: Li Kai Yuan , Cheng Xudong , Zhang Heping
Published: October 2013

This work is part of a wider scope of research on developing comprehensive pyrolysis model for medium density fibreboard (MDF) in fires. A simplified model is developed to predict the vertical density profile of virgin MDF. The model shows that vertical density profile can be reproduced using a second order conic curve. Several sets of experimental data are used to validate the model with promising results that are presented. Further investigation shows that the density difference between surface and core densities tends to maintain constant within a range of 300 to 450 kg/m3. Moreover, the model can predict the mean density with an error less than 30 kg/m3. Typical MDF panels were experimentally charred using thermogravimetric analysis and cone calorimetry to investigate the shrinkage and density of char. The actual char density is measured as 330 kg/m3 with a uniform density distribution along the char layer thickness. A model is developed to predict the shrinkage ratios. The restraining effect caused by surface deformation will lead to different vertical and horizontal shrinkage ratios. The volume reductions at vertical and horizontal directions are experimentally measured as 40% and 20% for the two tested MDF panels, which is comparable with the model predictions. Copyright © 2013 John Wiley & Sons, Ltd.
Accuracy and stability analysis of a second‐order time‐accurate loosely coupled partitioned algorithm for transient conjugate heat transfer problems
Authors: Kazemi‐Kamyab V. , van Zuijlen A. H. , Bijl H.
Published: October 2013

In this paper, a second‐order time‐accurate loosely coupled partitioned algorithm is presented for solving transient thermal coupling of solids and fluids, also referred to by conjugate heat transfer. The Crank–Nicolson scheme is used for time integration. The accuracy and stability of the loosely coupled solution algorithm are analyzed analytically. Based on the accuracy analysis, the design order of the time integration scheme is preserved by following a predictor (implicit)–corrector (explicit) approach. Hence, the need to perform an additional implicit solve (a subiteration) at each time step is avoided. The analytical stability analysis shows that by using the Crank–Nicolson scheme for time integration, the partitioned algorithm is unstable for large Fourier numbers, unlike the monolithic approach. Accordingly, using the stability analysis, a stability criterion is obtained for the Crank–Nicolson scheme that imposes restriction on Δt given the material properties and mesh spacings of the coupled domains. As the ratio of the thermal effusivities of the coupled domains reaches unity, the stability of the algorithm reduces. To demonstrate the applicability of the algorithm, a numerical example is considered (an unsteady conjugate natural convection in an enclosure). Copyright © 2013 John Wiley & Sons, Ltd.
Unconditionally stable numerical simulations of a new generalized reduced resistive magnetohydrodynamics model
Authors: Malapaka Shiva Kumar , Després Bruno , Sart Rémy
Published: October 2013

Reduced‐resistive magnetohydrodynamics (MHD) models are used in understanding different phenomenon in various domains, for example, astrophysics to model magnetotail or for solar arcades [Finn Bozkaya JM, Guzdar PN. Loss of equilibrium and reconnection in tearing of two dimensional equilibrias. Physics of Fluids B 1993; 5:2870–2876], modeling plasma confinements in reverse field pinch [Strauss HR. The dynamo effect in fusion plasmas. Physics of Fluids 1985; 28:2786–2792] and tokamaks [Strauss HR. Reduced MHD in nearly potential magnetic fields. Journal of Plasma Physics 1997; 57(1):83–87; Freidberg J. Plasma Physics and Fusion Energy. Cambridge University Press: Cambridge, 2008]. In this context, recently, a new generalized reduced‐resistive MHD model, which can make use of an arbitrary density profile was proposed [Després B, Sart R. Reduced resistive MHD in Tokamaks with general density. ESAIM: Mathematical Modelling and Numerical Analysis 2012; 46(5):1081–1106. EDP Sciences, SMAI, 2012 online 2011]. We in this work show that this proposed theoretical model can be realized numerically as well, and that it is very robust if the equation set is written in a very particular form using the properties of FEM. To illustrate these points, we pick the current hole configuration [Fujita T, Oikawa T, Suzuki T, Ide S, Sakamoto Y, Koide Y, Hatae T, Naito O, Isayama A, Hayashi N, Shirai H. Plasma equilibrium and confinement in a tokamak with nearly zero central current density in JT‐60U. Physical Review Letters 2001; 87(11):245001; Hawkes NC, Stratton BC, Tala T, Challis CD, Conway G, DeAngelis R, Giroud C, Hobirk J, Joffrin E, Lomas P, Lotte P, Mailloux J, Mazon D, Rachlew E, Reyes‐Cortes S, Solano E, Zastrow K‐D. Observation of zero current density in the core of JET discharges with lower hybrid heating and current drive. Physical Review Letters 2001; 87(11):115001], which was modeled using reduced‐resistive MHD and remodel it using different combinations of current sources and density profiles. Our model can be implemented with reasonable computational resources at the price of solving a well‐posed global linear system and it is unconditionally stable. These features are also demonstrated as a part of our numerical experiments. Copyright © 2013 John Wiley & Sons, Ltd.
The inhibitory effect of a fermented papaya preparation on growth, hydrophobicity, and acid production of Streptococcus mutans, Streptococcus mitis, and Lactobacillus acidophilus: its implications in oral health improvement of diabetics
Authors: Somanah Jhoti , Bourdon Emmanuel , Bahorun Theeshan , Aruoma Okezie I.
Published: October 2013

Fermented papaya preparation (FPP) is a “natural health product.” The high incidence of dental caries, gingivitis, periodontitis, and oral microbial infection cases among patients with diabetes mellitus continues to prevail. The potential role of FPP against common oral microbiota (Streptococcus mutans, Streptococcus mitis, and Lactobacillus acidophilus) isolated from the human oral cavity was investigated using in vitro simulation models of dental plaque and caries. FPP showed an inhibitory effect against the growth (at 0.05 mg/mL: S. mutans: −6.9%; S. mitis: −4.47%, P < 0.05), acid production (at 0.05 mg/mL: S. mutans: +6.38%; L. acidophilus: +2.25%), and hydrophobicity (at 50 mg/mL: S. mutans: 1.01%, P < 0.01; S. mitis: 7.66%, P < 0.05) of tested microbiota. The results of this study suggest that low doses of FPP may be a suitable complement to good oral hygiene practice for the effective prevention of dental caries, plaque, and gingivitis. The functional application of FPP as a constituent of a balanced diet and active lifestyle can make a positive contribution to the oral health status and well‐being of patients with diabetes.
Long‐Term Stability Studies of Anode‐Supported Microtubular Solid Oxide Fuel Cells
Authors: Laguna‐Bercero M. Á. , Férriz A. , Larrea Á. , Correas L. , Orera V. M.
Published: October 2013

A long‐term stability study of an anode‐supported NiO/YSZ‐YSZ‐LSM/YSZ microtubular cell was performed, under low fuel utilization conditions, using pure humidified hydrogen as fuel at the anode side and air at the cathode side. A first galvanometric test was performed at 766 °C and 200 mA cm–2, measuring a power output at 0.5 V of ∼250 mW cm–2. During the test, some electrical contact breakdowns at the anode current collector caused sudden current shutdowns and start‐up events. In spite of this, the cell performance remains unchanged. After a period of 325 h, the cell temperature and the current density was raised to 873°C and 500 mA cm–2, and the cell power output at 0.5 V was ∼600 mW cm–2. Several partial reoxidation events due to disturbance in fuel supply occurred, but no apparent degradation was observed. On the contrary, a small increase in the cell output power of about 4%/1,000 h after 654 h under current load was obtained. The excellent cell aging behavior is discussed in connection to cell configuration. Finally, the experiment concluded when the cell suffered irreversible damage due to an accidental interruption of fuel supply, causing a full reoxidation of the anode support and cracking of the thin YSZ electrolyte.
High resolution integrative analysis reveals widespread genetic and epigenetic changes after chronic in‐vitro acid and bile exposure in barrett's epithelium cells
Authors: Bajpai Manisha , Kessel Rachel , Bhagat Tushar , Nischal Sangeeta , Yu Yiting , Verma Amit , Das Kiron M.
Published: October 2013

Barrett's epithelium (BE) is a premalignant condition resulting from chronic gastroesophageal reflux that may progress to esophageal adenocarcinoma (EAC). Early intervention holds promise in preventing BE progression. However, identification of high‐risk BE patients remains challenging due to inadequate biomarkers for early diagnosis. We investigated the effect of prolonged chronic acid and bile exposure on transcriptome, methylome, and mutatome of cells in an in‐vitro BE carcinogenesis (BEC) model. Twenty weeks acid and bile exposed cells from the BEC model (BEC20w) were compared with their naïve predecessors HiSeq Illumina based RNA sequencing was performed on RNA from both the cells for gene expression and mutational analysis. HELP Tagging Assay was performed for DNA methylation analysis. Ingenuity pathway, Gene Ontology, and KEGG PATHWAY analyses were then performed on datasets. Widespread aberrant genetic and epigenetic changes were observed in the BEC20w cells. Combinatorial analyses revealed 433 from a total of 863 downregulated genes had accompanying hypermethylation of promoters. Simultaneously, 690 genes from a total of 1,492 were upregulated with accompanying promoter hypomethylation. In addition, 763 mutations were identified on 637 genes. Ingenuity pathway analysis, Gene Ontology, and KEGG PATHWAY analyses associated the genetic and epigenetic changes in BEC20w cells with cellular and biological functions. Integration of high resolution comparative analyses of naïve BAR‐T and BEC20w cells revealed striking genetic and epigenetic changes induced by chronic acid and bile exposure that may disrupt normal cellular functions and promote carcinogenesis. This novel study reveals several potential targets for future biomarkers and therapeutic development. © 2013 Wiley Periodicals, Inc.
A comparison of water chemistry from a CO2‐enhanced oil recovery project with reactive transport modeling of CO2 injection into a carbonate reservoir
Authors: Shevalier Maurice , Nightingale Michael , Dalkhaa Chantsalmaa , Mayer Bernhard
Published: October 2013

A long‐term geochemical monitoring program was conducted at a CO2‐enhanced oil recovery site in central Alberta (Canada) to examine geological storage of CO2. The program included geochemical monitoring of reservoir brines, a mineralogical study, and using TOUGHREACT to compare model and field observations. CO2 was injected into a highly permeable carbonate reservoir at 78 tonnes/day for 2.5 years. Fluid and gas samples were obtained for geochemical characterization before, during, and 1.4 years after injection from a production well ∼915 m from the injection well at a depth of ∼936 m. Downhole water compositions were calculated using SOLMINEQ88 and compared to predictions from TOUGHREACT. Following CO2 breakthrough after ∼23 months, downhole pH decreased, HCO3−; and calcium concentrations increased, while magnesium concentrations changed marginally, indicating solubility and ionic trapping were occurring simultaneously. Trends in analyzed and modeled species were similar, but concentration levels were different. Calibrating the model to achieve better correlation between results was attempted but proved unsuccessful. The variances were likely caused by differences between ideal and reservoir mineral's kinetic parameters, surface area, thermodynamic parameters and sampling technique. Five‐hundred‐year simulations showed the CO2 plume migrating vertically due to capillary forces with no significant change in gas saturation below the caprock over the post‐injection period. The majority of CO2 remained trapped as a supercritical phase as the reservoir is composed of only carbonate minerals. The low reactivity of the reservoir is positive, in that the reservoir is not negatively impacted by dissolution and negative in that no mineral trapping occurs. © 2013 Society of Chemical Industry and John Wiley & Sons, Ltd
Catalytic hydrolysis of trifluoromethane over alumina
Authors: Han Wenfeng , Chen Yuliang , Jin Bibo , Liu Huazhang , Yu Hai
Published: October 2013

Catalytic hydrolysis over alumina was carried out at temperatures between 350 °C and 520 °C and gas hourly space velocity (GHSV) of 6000 h−1. The effects of water vapor concentration, alumina phase, and Zn promoter as well as the reaction mechanism were investigated in detail. The results show that the presence of small amounts of water vapor (0.8%) significantly improves the activity of γ‐Al2O3, while higher water vapor concentration (>2.8%) does not further enhance the decomposition of CHF3. Compared with γ‐Al2O3 and AlOOH, α‐Al2O3 is inactive for the targeted reaction although it is stable under conditions studied (with the presence of HF product). Zn is an efficient promoter for the improvement of activity and stability of alumina catalyst. More attention is paid to the reaction and deactivation mechanism. Based on the experimental results and thermodynamic analysis, a reaction mechanism is proposed which explains the effect of water vapor and deactivation of catalyst reasonably.
Regional CO2 sequestration capacity assessment for the coastal and offshore Texas Miocene interval
Authors: Wallace Kerstan J , Meckel Timothy A , Carr David L. , Treviño Ramón H , Yang Changbing
Published: October 2013

Estimating regional geologic storage capacity potential for carbon dioxide will play an important role in determining the feasibility of widespread carbon capture and storage (CCS) programs in the United States and worldwide. The sandstone reservoirs of the Miocene Age located off the Texas coast in the northern Gulf of Mexico are a promising target for CCS due to favorable geologic properties (high porosity/permeability, effective traps and seals, etc.) and proximity to high carbon dioxide emission sources. The common method for regional storage capacity estimation involves the calculation of a pore volume which is modified by some discount or efficiency factor. Though efficiency factors have a large effect on calculated capacity, little work has been done to validate the use and effectiveness of these terms. In this paper we aim to provide an estimate for the storage potential of the coastal and offshore Texas Miocene interval using a common calculation methodology and to begin expanding on this calculation by developing and incorporating an additional sand picking refinement step. This step allows for an initial investigation into the accuracy and utility of typical efficiency factors and regional storage calculations. We find that in our study area, capacity that is calculated using the actual net sand thickness, or ‘net capacity’, is ∼25% less than capacity that is calculated using the total interval thickness, or ‘gross capacity’, though, ideally, the two should be equal. Discrepancies between the two calculations emphasize the large uncertainty inherent in efficiency factors and highlight the need for further investigation.
Value of EQ‐5D in Mexican city older population with and without dementia (SADEM study)
Authors: Sanchez‐Arenas Rosalinda , Vargas‐Alarcon Gilberto , Sanchez‐Garcia Sergio , Garcia‐Peña Carmen , Gutierrez‐Gutierrez Lidia , Grijalva Israel , Garcia‐Dominguez Angelica , Juárez‐Cedillo Teresa
Published: October 2013

Background

The EuroQoL‐5D (EQ‐5D) is a brief, multi‐attribute, preference‐based health status measurement. The objective of this study was to assess the validity and reliability of EQ‐5D in older adults with and without dementia in Mexico City.

Methods

The Study on Aging and Dementia in Mexico (SADEM) was a survey of 3101, Mexican adults (60 + years old). An in‐home face‐to‐face interview was administered. EQ‐5D using ranking to rate states on a 100‐point visual analogue scale; Daily Living Activities (ADL), Instrumental Activities of Daily Living (IADL), Mini Mental State Examination (MMSE), Short Form of the quality of life survey (SF‐36), and Charlson comorbility index were used for comparison. The validity and reliability of EQ‐5D were tested. We identified states of health for direct valuation; state 11111 (“no problems”) had to be included because it was essential to the reseating (onto a 0–1 scale) of the visual analogue scale data. We included all plausible combinations of levels across each of the five EQ‐5D dimensions and evaluated any significant interaction effects and factorial designs, based on balanced complete blocks.

Results

The EQ‐5D was applied to 3101 older people, of whom 109 (3.4%) had dementia. The general reliability of EQ‐5D for cases was 0.80 and for controls 0.76, for each dimension. We had a total of 103 combinations for controls and 45 for cases. The percentage for the state of health “no problems” (11111) for controls was 30.4%, and had the highest percentage of cases (8.8%).

Conclusion

The resulting valuations form the basis for clinical use and facilitate the interpretation and evaluation of health care. Copyright © 2013 John Wiley & Sons, Ltd.
Systematic review and meta‐analysis to estimate potential recruitment to dementia intervention studies
Authors: Cooper Claudia , Ketley Daniel , Livingston Gill
Published: October 2013

Objective

We investigated the proportion of people with dementia who are eligible for and willing to participate in intervention studies.

Methods

We systematically reviewed 12 studies fitting predetermined criteria, reporting eligibility or participation rates for dementia intervention trials or intervention studies that sought to increase recruitment. We assessed the study validity using a checklist, reported trial eligibility and participation rates and meta‐analysed these where appropriate.

Results

In higher quality studies, 26% [95% confidence interval 19–35%] of people with Alzheimer's disease (AD) attending memory clinics or receiving antidementia medication were eligible for industry drug trials, and 43% of eligible people agreed to participate in one study, suggesting 11% of these populations would take part in drug trials if approached. There was replicated, higher quality evidence that younger people, men and those with more education were more likely to be eligible for AD drug trials. No randomised controlled trials have investigated how to increase recruitment to dementia intervention studies.

Conclusion

One in 10 people with AD or taking donepezil would, according to best available evidence, take part in industry drug trials if approached. We found no data regarding non‐pharmacological intervention or pragmatic drug trial recruitment, but eligibility and participation rates for these studies are probably higher. If international studies are extrapolated to the UK, they suggest the national target of recruiting 10% of people with dementia diagnoses to research may be achieved through a nationwide policy of asking all people with dementia and their carers for consent to be approached for research participation. Copyright © 2013 John Wiley & Sons, Ltd.
Shape evolution and finite deformation pattern in analog experiments of lithosphere necking
Authors: Nestola Yago , Storti Fabrizio , Bedogni Enrico , Cavozzi Cristian
Published: October 2013

Lithosphere necking evolution determines the 3‐D architecture of crustal and upper mantle thinning and related basins, and the heat flow distribution in rifted regions. Despite a large number of studies, lithosphere necking evolution is still a matter of debate. We present the result from lithospheric‐scale analog models designed for investigating the necking shape during extension and the vertical distribution of finite deformation in the mechanical lithosphere. In our experiments, lithosphere necking is asymmetric and, in particular, the 3‐D distribution of thinning is cylindrical in the crust and very heterogeneous in the mantle. Overall, the evolution of rifting and necking progresses from delocalized to localized deformation.
Spatial and temporal patterns of simulated slow slip events on the Cascadia megathrust
Authors: Colella Harmony V. , Dieterich James H. , Richards‐Dinger Keith
Published: October 2013

In recent years, it has been discovered that sections of the subduction interface slip aseismically in slow slip events, during which stress is intermittently transferred to the section of the subduction zone that generates large or great earthquakes. Within the Cascadia subduction zone, the magnitude and frequency of SSEs and accompanying tectonic tremor exhibit complex patterns that vary systematically with depth. However, the loading mechanisms and interactions that precede great subduction earthquakes are poorly understood. Here we present results from physics‐based simulations that reproduce the continuum of SSE characteristics reported for the Cascadia subduction zone. The simulations provide a basis for understanding the interactions that control both the observed complex patterns of SSEs and stress transfer to the seismogenic section that produce great earthquakes.
The multiple spots of the Ganymede auroral footprint
Authors: Bonfond B. , Hess S. , Bagenal F. , Gérard J.‐C. , Grodent D. , Radioti A. , Gustin J. , Clarke J. T.
Published: October 2013

The interaction between the moons and the magnetosphere of giant planets sometimes gives rise to auroral signatures in the planetary ionosphere, called the satellite footprints. So far, footprints have been detected for Io, Europa, Ganymede, and Enceladus. These footprints are usually seen as single spots. However, the Io footprint, the brightest one, displays a much more complex morphology made of at least three different spots and an extended tail. Here we present Hubble Space Telescope FUV images showing evidence for a second spot in the Ganymede footprint. The spots separation distance changes as Ganymede moves latitudinally in the plasma sheet, as is seen for the Io footprint. This indicates that the processes identified at Io are universal. Moreover, for similar Ganymede System III longitudes, the distance may also vary significantly with time, indicating changes in the plasma sheet density. We identified a rapid evolution of this distance ∼8 days after the detection of a volcanic outburst at Io, suggesting that such auroral observations could be used to estimate the plasma density variations at Ganymede.
Wavy magnetodisk in Saturn's outer magnetosphere
Authors: Carbary J. F.
Published: October 2013

A simple wavy magnetodisk model can explain periodicities in energetic charged particles observed in Saturn's outer magnetosphere (>20 RS). The model's free parameters are the tilt of magnetodisk in inner magnetosphere (~1.8°), speed of outgoing spiral wave (~8 RS/h), critical radius (~10 RS), and period of rotation (10.64 h). The fidelity of the model is not judged by a least squares fit to the actual data, but rather by the model's accuracy in reproducing the Lomb periodogram of the periodicities. The model accurately simulates the main spectral feature near ~10.7 h plus a secondary (“dual”) period near ~10.95 h. The ability of the wavy magnetodisk with one period to produce the observed dual periodicity in the observations suggests that models having “dual” periods need not be invoked to explain some of the periodicities in Saturn's outer magnetosphere.
Critical role for mesoscale eddy diffusion in supplying oxygen to hypoxic ocean waters
Authors: Gnanadesikan Anand , Bianchi Daniele , Pradal Marie‐Aude
Published: October 2013

Estimates of the oceanic lateral eddy diffusion coefficient Aredi vary by more than an order of magnitude, ranging from less than a few hundred m2/s to thousands of m2/s. This uncertainty has first‐order implications for the intensity of oceanic hypoxia, which is poorly simulated by the current generation of Earth System Models. Using satellite‐based estimate of oxygen consumption in hypoxic waters to estimate the required diffusion coefficient for these waters gives a value of order 1000 m2/s. Varying Aredi across a suite of Earth System Models yields a broadly consistent result given a thermocline diapycnal diffusion coefficient of 1 × 10−5 m2/s.
Comprehensive model of short‐ and long‐term slow slip events in the Shikoku region of Japan, incorporating a realistic plate configuration
Authors: Matsuzawa Takanori , Shibazaki Bunichiro , Obara Kazushige , Hirose Hitoshi
Published: October 2013

We numerically simulate slow slip events (SSEs) in the Shikoku region of Japan, incorporating the configuration of the subducting plate. We adopt a rate‐ and state‐dependent friction law with cutoff velocities, assuming a frictional parameter distribution based on observed long‐term SSEs and nonvolcanic tremors that reflects the slip of short‐term SSEs. Our model reproduces recurrences of long‐ and short‐term SSEs and segments of short‐term SSEs. In our simulation, short‐term SSEs' transition from episodic to continuous slip is reproduced. This feature is consistent with tremor activity recently reported in both Shikoku and Cascadia. In addition to the long‐term SSEs in the Bungo Channel, our model also reproduces newly found long‐term SSEs in central Shikoku and predicts that these SSEs recur during the interseismic period between megathrust earthquakes. Our model comprehensively reproduces various SSEs and their characteristics as reported in the Shikoku region.
Can we distinguish canonical El Niño from Modoki?
Authors: Karnauskas Kristopher B.
Published: October 2013

Following the recent discovery of the “Modoki” El Niño, a proliferation of studies and debates has ensued concerning whether Modoki is dynamically distinct from “Canonical” El Niño, how Modoki impacts and teleconnections differ, and whether Modoki events have been increasing in frequency or amplitude. Three decades of reliable, high temporal‐resolution observations of coupled ocean‐atmosphere variability in the equatorial Pacific reveal a rich diversity of El Niños. Although central and eastern Pacific sea surface temperature (SST) anomalies appear mechanistically separable in terms of local and remote forcing, their frequent overlap precludes robust classifications. All observed El Niños appear to be a mixture of locally (central Pacific) and remotely forced (eastern Pacific) SST anomalies. Submonthly resolution appears essential for this insight and for the proper dynamical diagnosis of El Niño evolution; thus, the use of long‐term monthly reconstructions for classification and trend analysis is strongly cautioned against.
Reduced functional connectivity within the limbic cortico‐striato‐thalamo‐cortical loop in unmedicated adults with obsessive‐compulsive disorder
Authors: Posner Jonathan , Marsh Rachel , Maia Tiago V. , Peterson Bradley S. , Gruber Allison , Simpson H. Blair
Published: October 2013

Cortico‐striato‐thalamo‐cortical (CSTC) loops project from the cortex to the striatum, then from the striatum to the thalamus via the globus pallidus, and finally from the thalamus back to the cortex again. These loops have been implicated in Obsessive‐Compulsive Disorder (OCD) with particular focus on the limbic CSTC loop, which encompasses the orbitofrontal and anterior cingulate cortices, as well as the ventral striatum. Resting state functional‐connectivity MRI (rs‐fcMRI) studies, which examine temporal correlations in neural activity across brain regions at rest, have examined CSTC loop connectivity in patients with OCD and suggest hyperconnectivity within these loops in medicated adults with OCD. We used rs‐fcMRI to examine functional connectivity within CSTC loops in unmedicated adults with OCD (n = 23) versus healthy controls (HCs) (n = 20). Contrary to prior rs‐fcMRI studies in OCD patients on medications that report hyperconnectivity in the limbic CSTC loop, we found that compared with HCs, unmedicated OCD participants had reduced connectivity within the limbic CSTC loop. Exploratory analyses revealed that reduced connectivity within the limbic CSTC loop correlated with OCD symptom severity in the OCD group. Our finding of limbic loop hypoconnectivity in unmedicted OCD patients highlights the potential confounding effects of antidepressants on connectivity measures and the value of future examinations of the effects of pharmacological and/or behavioral treatments on limbic CSTC loop connectivity. Hum Brain Mapp 35:2852–2860, 2014. © 2013 Wiley Periodicals, Inc.
Optically Active S‐Esters of Dithiophosphoric Acid on the Basis of (1S)‐endo‐(–)‐Borneol
Authors: Nizamov Ilyas S. , Gabdullina Gulnara T. , Nurmukhametov Almaz R. , Nizamov Ilnar D. , Cherkasov Rafael A.
Published: October 2013

The ammonium salt of optically active dithiophosphoric acid obtained by the reaction of tetraphosphorus decasulfide with (1S)‐endo‐(–)‐borneol reacts with benzoyl chloride, methyl chloroacetate and epichlorohydrin to form novel dithiophosphate S‐esters.
INTER‐PROVIDER COMPARISON OF PATIENT‐REPORTED OUTCOMES: DEVELOPING AN ADJUSTMENT TO ACCOUNT FOR DIFFERENCES IN PATIENT CASE MIX
Authors: Nuttall David , Parkin David , Devlin Nancy
Published: October 2013

This paper describes the development of a methodology for the case‐mix adjustment of patient‐reported outcome measures (PROMs) data permitting the comparison of outcomes between providers on a like‐for‐like basis. Statistical models that take account of provider‐specific effects form the basis of the proposed case‐mix adjustment methodology. Indirect standardisation provides a transparent means of case mix adjusting the PROMs data, which are updated on a monthly basis. Recently published PROMs data for patients undergoing unilateral knee replacement are used to estimate empirical models and to demonstrate the application of the proposed case‐mix adjustment methodology in practice. The results are illustrative and are used to highlight a number of theoretical and empirical issues that warrant further exploration. For example, because of differences between PROMs instruments, case‐mix adjustment methodologies may require instrument‐specific approaches. A number of key assumptions are made in estimating the empirical models, which could be open to challenge. The covariates of post‐operative health status could be expanded, and alternative econometric methods could be employed. © 2013 Crown copyright.
IS THE MEDICAL LOSS RATIO A GOOD TARGET MEASURE FOR REGULATION IN THE INDIVIDUAL MARKET FOR HEALTH INSURANCE?
Authors: Karaca‐Mandic Pinar , Abraham Jean M. , Simon Kosali
Published: October 2013

Effective January 1, 2011, individual market health insurers must meet a minimum medical loss ratio (MLR) of 80%. This law aims to encourage ‘productive’ forms of competition by increasing the proportion of premium dollars spent on clinical benefits. To date, very little is known about the performance of firms in the individual health insurance market, including how MLRs are related to insurer and market characteristics. The MLR comprises one component of the price–cost margin, a traditional gauge of market power; the other component is percent of premiums spent on administrative expenses. We use data from the National Association of Insurance Commissioners (2001–2009) to evaluate whether the MLR is a good target measure for regulation by comparing the two components of the price–cost margin between markets that are more competitive versus those that are not, accounting for firm and market characteristics. We find that insurers with monopoly power have lower MLRs. Moreover, we find no evidence suggesting that insurers' administrative expenses are lower in more concentrated insurance markets. Thus, our results are largely consistent with the interpretation that the MLR could serve as a target measure of market power in regulating the individual market for health insurance but with notable limited ability to capture product and firm heterogeneity. Copyright © 2013 John Wiley & Sons, Ltd.
MEASURING OVERFITTING IN NONLINEAR MODELS: A NEW METHOD AND AN APPLICATION TO HEALTH EXPENDITURES
Authors: Bilger Marcel , Manning Willard G.
Published: October 2013

When fitting an econometric model, it is well known that we pick up part of the idiosyncratic characteristics of the data along with the systematic relationship between dependent and explanatory variables. This phenomenon is known as overfitting and generally occurs when a model is excessively complex relative to the amount of data available. Overfitting is a major threat to regression analysis in terms of both inference and prediction.

We start by showing that the Copas measure becomes confounded by shrinkage or expansion arising from in‐sample bias when applied to the untransformed scale of nonlinear models, which is typically the scale of interest when assessing behaviors or analyzing policies. We then propose a new measure of overfitting that is both expressed on the scale of interest and immune to this problem. We also show how to measure the respective contributions of in‐sample bias and overfitting to the overall predictive bias when applying an estimated model to new data.

We finally illustrate the properties of our new measure through both a simulation study and a real‐data illustration based on inpatient healthcare expenditure data, which shows that the distinctions can be important. Copyright © 2013 John Wiley & Sons, Ltd.
Verification bias in diagnostic accuracy studies for fine‐ and core needle biopsy of salivary gland lesions in otolaryngology journals: A systematic review and analysis
Authors: Schmidt Robert L. , Jedrzkiewicz Jolanta D. , Allred Rebecca J. , Matsuoka Shotaro , Witt Benjamin L.
Published: October 2013

Background

Diagnostic test accuracy (DTA) studies for needle biopsy are frequently published in otolaryngology journals, but this body of literature has not been assessed for verification bias.

Methods

We conducted a systematic review of DTA studies on needle biopsy of salivary gland lesions appearing in otolaryngology journals. Studies were assessed by 2 reviewers for verification bias.

Results

We identified 95 DTA studies for needle biopsy of salivary gland lesions. Eighty‐one studies (84%) had verification bias. Five of the biased studies provided sufficient data to estimate the extent of bias. Verification bias was associated with an overestimate of sensitivity and an underestimate of specificity. Studies on core needle biopsy (CNB) had a lower rate of verification bias than fine‐needle aspiration (FNA) studies.

Conclusion

Verification bias is common in DTA studies of needle biopsy for salivary gland lesions published in ear, nose, and throat (ENT) journals. Such studies overestimated sensitivity and underestimated specificity. © 2014 Wiley Periodicals, Inc. Head Neck 36: 1654–1661, 2014