bluuebunny/crossref_metadata_2025 huggingface dataset:
Fitting meta‐analytic structural equation models with complex datasets
Authors: Wilson Sandra Jo , Polanin Joshua R. , Lipsey Mark W.
Published: June 2016

A modification of the first stage of the standard procedure for two‐stage meta‐analytic structural equation modeling for use with large complex datasets is presented. This modification addresses two common problems that arise in such meta‐analyses: (a) primary studies that provide multiple measures of the same construct and (b) the correlation coefficients that exhibit substantial heterogeneity, some of which obscures the relationships between the constructs of interest or undermines the comparability of the correlations across the cells. One component of this approach is a three‐level random effects model capable of synthesizing a pooled correlation matrix with dependent correlation coefficients. Another component is a meta‐regression that can be used to generate covariate‐adjusted correlation coefficients that reduce the influence of selected unevenly distributed moderator variables. A non‐technical presentation of these techniques is given, along with an illustration of the procedures with a meta‐analytic dataset. Copyright © 2016 John Wiley & Sons, Ltd.
Random‐effects meta‐analysis for systematic reviews of phase I clinical trials: Rare events and missing data
Authors: Kim Mi‐Ok , Wang Xia , Liu Chunyan , Dorris Kathleen , Fouladi Maryam , Song Seongho
Published: June 2016

Phase I trials aim to establish appropriate clinical and statistical parameters to guide future clinical trials. With individual trials typically underpowered, systematic reviews and meta‐analysis are desired to assess the totality of evidence. A high percentage of zero or missing outcomes often complicate such efforts. We use a systematic review of pediatric phase I oncology trials as an example and illustrate the utility of advanced Bayesian analysis. Standard random‐effects methods rely on the exchangeability of individual trial effects, typically assuming that a common normal distribution sufficiently describes random variation among the trial level effects. Summary statistics of individual trial data may become undefined with zero counts, and this assumption may not be readily examined. We conduct Bayesian semi‐parametric analysis with a Dirichlet process prior and examine the assumption. The Bayesian semi‐parametric analysis is also useful for visually summarizing individual trial data. It provides alternative statistics that are computed free of distributional assumptions about the shape of the population of trial level effects. Outcomes are rarely entirely missing in clinical trials. We utilize available information and conduct Bayesian incomplete data analysis. The advanced Bayesian analyses, although illustrated with the specific example, are generally applicable. © 2016 The Authors. Research Synthesis Methods Published by John Wiley & Sons Ltd.
Intervention of pumpkin seed oil on metabolic disease revealed by metabonomics and transcript profile
Authors: Zhao Xiu‐Ju , Chen Yu‐Lian , Fu Bing , Zhang Wen , Liu Zhiguo , Zhuo Hexian
Published: June 2016

BACKGROUND

Understanding the metabolic and transcription basis of pumpkin seed oil (PSO) intervention on metabolic disease (MD) is essential to daily nutrition and health.

RESULTS

This study analyzed the liver metabolic variations of Wistar rats fed normal diet (CON), high‐fat diet (HFD) and high‐fat plus PSO diet (PSO) to establish the relationship between the liver metabolite composition/transcript profile and the effects of PSO on MD. By using proton nuclear magnetic resonance spectroscopy together with multivariate data analysis, it was found that, compared with CON rats, HFD rats showed clear dysfunctions of choline metabolism, glucose metabolism and nucleotide and amino acid metabolism. Using quantitative real‐time polymerase chain reaction (qPCR), it was found that, compared with HFD rats, PSO rats showed alleviated endoplasmic reticulum stress accompanied by lowered unfolded protein response.

CONCLUSION

These findings provide useful information to understand the metabolic alterations triggered by MD and to evaluate the effects of PSO intervention. © 2016 Society of Chemical Industry
Profiling and analysis of multiple compounds in rhubarb decoction after processing by wine steaming using UHPLC–Q‐TOF‐MS coupled with multiple statistical strategies
Authors: Zhu Tingting , Liu Xiao , Wang Xiaoli , Cao Gang , Qin Kunming , Pei Ke , Zhu Hui , Cai Hao , Niu Minjie , Cai Baochang
Published: June 2016

Rhubarb is one of the most popular traditional Chinese medicines and has been used for thousands of years in many Asian countries. Prepared rhubarb is obtained by steaming raw rhubarb with glutinous rice wine until it turned black in appearance both inside and outside. After processing, the therapeutic effects of prepared rhubarb change a lot. To find out the exact compound changes of the chemical profile in a decoction of rhubarb after processing and to clarify the material basis of the changed therapeutic effects, an ultra‐high performance liquid chromatography with quadrupole time‐of‐flight mass spectrometry method coupled with automated data analysis software and statistical strategy was developed. As a result, 63 peaks in raw rhubarb and 54 peaks in prepared rhubarb were detected, and a total of 45 chemical compounds were identified. The analysis data were subjected to a principle component analysis and a t‐test. Based on the results, 16 peaks were found to be the main contributors to the significant difference (p < 0.05) between raw and prepared rhubarb. Compared with raw rhubarb, the content of 15 components in prepared rhubarb was lower, while only rhein (1,8‐dihydroxy‐3‐carboxy anthraquinone) showed a higher intensity.
Tribological characteristics of bisphenol S bis(diphenyl phosphate) as a high‐performance antiwear additive in lubricating greases at elevated temperature
Authors: Zhu Lili , Wu Xinhu , Zhao Gaiqing , Wang Xiaobo
Published: June 2016

Bisphenol S bis(diphenyl phosphate) (BSDP) was synthesised and characterised, and its tribological behaviours as additives in polyurea grease and lithium complex grease were evaluated for steel/steel contact at 200 °C. The results indicated that BSDP could dramatically reduce the friction and wear of sliding pairs in the base grease of polyurea, and the tribological performances of BSDP in polyurea grease were significantly superior to the normally used molybdenum disulfide‐based additive package. Furthermore, BSDP in polyurea grease has better tribological behaviour than that in lithium complex grease at a constant load of 100 N. X‐ray photoelectron spectroscopy analysis indicated that boundary lubrication films composed of Fe(OH)O, Fe2O3, Fe3O4 and FePO4 compounds containing the P–O bonds and nitride compounds were formed on the worn surface, which resulted in excellent friction reduction and antiwear performance. Copyright © 2016 John Wiley & Sons, Ltd.
Reissner–Mindlin shell implementation and energy conserving isogeometric multi‐patch coupling
Authors: Sommerwerk K. , Woidt M. , Haupt M. C. , Horst P.
Published: June 2016

A shear‐flexible isogeometric Reissner–Mindlin shell formulation using non‐uniform rational B‐splines basis functions is introduced, which is used for the demonstration of a coupling approach for multiple non‐conforming patches. The six degrees of freedom formulation uses the exact surface normal vectors and curvature. The shell formulation is implemented in an isogeometric analysis framework for computation of structures composed of multiple geometric entities. To enable local model refinement as well as non‐matching domains coupling, a conservative multi‐patch approach using Lagrange multipliers for structured non‐uniform rational B‐splines patches is presented. Here, an additional border frame mesh is used to couple geometries during structural analyses. This frame interface approach avoids the problem of excessive constraints when multiple patches are coupled at one point. First, the shell formulation is verified with several reference cases. Then the influence of the frame interface discretization and frame penalty stiffness on the smoothness of the results is investigated. The effects of the perturbed Lagrangian method in combination with the frame interface approach is shown. In addition, results of models with T‐joint interface connections and perpendicular stiffener patches are presented. Copyright © 2016 John Wiley & Sons, Ltd.
Reinforcing effect of surface‐modified multiwalled carbon nanotubes on flexural response of E‐glass/epoxy isogrid‐stiffened composite panels
Authors: Khosravi Hamed , Eslami‐Farsani Reza
Published: June 2016

The lack of scientific information about the utilization of nanoparticles on grid‐stiffened composite (GSC) fabrication was the driving force for the selection of this study. In the present work, GSC panels reinforced with various amounts of surface modified multi‐walled carbon nanotubes (MWCNTs) (0–0.5 wt% at a step of 0.1 wt%) have been investigated in terms of their capability to improve the mechanical properties under three‐point flexural condition. Out of these specimens, the maximum value of improvement in the flexural stiffness, load bearing capacity, and specific energy absorption was related to the specimen with 0.4 wt% MWCNTs. It would be worth mentioning that in these structures, a considerable energy absorption was observed after the primary failure related to the load peak. The field‐emission scanning electron microscopy observations of the fracture surfaces of the nanocomposites clearly indicated that the enhancement in the flexural properties was due to the improvement in the interfacial adhesion between the E‐glass fibers and MWCNTs‐enhanced epoxy matrix. POLYM. COMPOS., 39:E677–E686, 2018. © 2016 Society of Plastics Engineers
The impact of pre‐diabetes diagnosis on behaviour change: an integrative literature review
Authors: Youngs W , Gillibrand WP , Phillips S
Published: June 2016

Type 2 diabetes is a growing global problem that not only affects individuals but also has an impact upon the economic health of countries. The number of people developing type 2 diabetes can be reduced by up to by 80%; this can be achieved by targeting those who are ‘at risk’. This reduction can be achieved by appropriate lifestyle changes to diet and physical activity. It is not known what the impact of being informed of a diagnosis of pre‐diabetes has on an individual's motivation to make appropriate lifestyle changes.

The aim of this study was to assess whether having the diagnosis of pre‐diabetes encourages or empowers people to make appropriate lifestyle changes to prevent progression to a diagnosis of type 2 diabetes.

Employing a systematic approach, an integrative literature review was undertaken using a standard retrieval and appraisal method. The studies demonstrated that pre‐diabetes was found to be a challenging concept by patients and nurses alike. Lack of knowledge and support, along with patients’ perceived barriers, had an impact upon the various motivation and self‐efficacy behaviours towards lifestyle changes.

The integrative review found that more education and support are required to motivate lifestyle change in the person with pre‐diabetes. This, however, does not need to be medicine led; use of peer and community based programmes could be not only cheaper, but also have the ability to provide potentially long‐term support for people, and would provide continued reduced risk. Intervention needs to ensure that it is provided at an appropriate level to account for cultural, social and gender needs. Innovative approaches need to be considered to reduce the number of people who are diagnosed with pre‐diabetes from progressing to type 2 diabetes and its associated potential complications. Copyright © 2016 John Wiley & Sons.
Intra‐ and inter‐supramolecular complexation of poly(butyl methacrylate)‐co‐2‐(1,2,3‐triazol‐4‐yl)pyridine copolymers induced by CoII, FeII, and EuIII ions monitored by molecular hydrodynamics methods
Authors: Pavlov Georges M. , Perevyazko Igor , Happ Bobby , Schubert Ulrich S.
Published: June 2016

Poly(butyl methacrylate) copolymers embedding bidentate 2‐(1,2,3‐triazol‐4‐yl)pyridine (trzpy) chelating units as comonomer in the side chains were synthesized by controlled radical addition‐fragmentation transfer (RAFT) polymerization. Intracomplexation and intercomplexation of the macromolecules of the poly(butyl methacrylate) copolymers containing 20 % mol of trzpy units induced by CoII, FeII, and EuIII ions were studied in the solutions by macromolecular hydrodynamics methods. The sedimentation velocity of extremely diluted copolymer solutions and the dynamic viscosity of moderately diluted solutions were studied in a wide range of the salts concentrations. Differences were observed with respect to the copolymer behavior in the presence of the Co2+, Fe2+, Eu3+ ions. These differences are namely due to the differences in the number of coordination bonds required for complex formation and not explicitly to the nature of the corresponding anions. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 2632–2639
Fast and slow lifetime degradation in boron‐doped Czochralski silicon described by a single defect
Authors: Hallam Brett , Abbott Malcolm , Nærland Tine , Wenham Stuart
Published: June 2016

A demonstration that boron–oxygen related degradation in boron‐doped Czochralski silicon could be caused by a single defect with two trap energy levels is presented. In this work, the same two‐level defect can describe the fast and slow lifetime decay with a capture cross‐section ratio of electrons and holes for the donor level of σn/σp = 19 ± 4. A model is proposed for the multi‐stage degradation involving a single defect, in which the product of the slow reaction is a reactant in the fast reaction. After thermal processing, a population of interstitial oxygen (Oi) exists in a certain state (the precursor state) that can rapidly form defects (fast degradation) and another population of Oi exists in a state that is required to undergo a slow transformation into the precursor state before defect formation can proceed (slow degradation). Kinetic modelling is able to adequately reproduce the multi‐stage degradation for experimental data. Dark annealing is also shown to impact the extent of ‘fast’ degradation. By decreasing the dark annealing time on pre‐degraded wafers, a more severe ‘fast’ degradation of the samples can be enabled during subsequent illumination, consistent with this theory. The paper then discusses possible candidates for the chemical species involved. (© 2016 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)
Fault Diagnosis Improvement Using Dynamic Fault Model in Optimal Sensor Placement: A Case Study of Steam Turbine
Authors: Salehpour‐Oskouei Farzin , Pourgol‐Mohammad Mohammad
Published: June 2016

Health data are collected dominantly through sensors mounted on different locations in the system. Optimization of sensor network has a significant influence on the reliability of system health prognostics process. In this research, the effect of sensors reliability is studied on their placement optimization. Sensors are considered in this study as components in system failure model. This study is aimed to use ‘Priority AND’ gate for evaluating the effect of time dependencies of sensors as well as components failure on the optimal sensor placement. Because of that, PAND gate is added to the fault tree between all sensors and their corresponding components to develop the failure model of each sensor placement scenario. For calculating the probability of top event, a Monte Carlo‐based algebraic approach is proposed. In algebraic approach, temporal operator ‘BEFORE’ is proposed for calculating the probability of ‘PAND’ gate. The result of using ‘BEFORE’ operator is an analytical solution for probability of each cut sequence. Because of the complexity of analytical solution in practical problems, a Monte Carlo simulation is utilized on the solution in this research. Then the probability of each cut sequence is calculated. Consequently, the probability of top event for each scenario is obtained. Finally, all scenarios are ranked based on top event probabilities. As a case study, optimization of sensor placement has been demonstrated on steam turbine and results are discussed. Copyright © 2016 John Wiley & Sons, Ltd.
Formation of Mn‐Co‐Ni‐O Nanoceramic Microspheres Using In Situ Ink‐Jet Printing: Sintering Process Effect on the Microstructure and Electrical Properties
Authors: Chen Long , Zhang Qinan , Yao Jincheng , Wang Junhua , Kong Wenwen , Jiang Chunping , Chang Aimin
Published: June 2016

Mn‐Co‐Ni‐O nanoceramic microspheres with high density, uniformity, and size tunability are successfully fabricated using in situ ink‐jet printing and two step sintering (TSS) techniques. The microspheres, synthesized by an effective and facile reverse microemulsion method, consist of uncalcined Mn‐Co‐Ni‐O nanocrystallines that show a well formed single tetragonal spinel phase and an average particle size distribution of ≈20 nm. The sintering behavior, microstructure, and electrical properties of the Mn‐Co‐Ni‐O nanoceramic microspheres are systematically investigated and characterized. The results indicate that the sintered Mn‐Co‐Ni‐O nanoceramic microspheres show high density and improved electrical properties. The highest R25, B25/50, Ea, and α25 values achieved at sintering temperature of 1150 °C are 4846.7 KΩ, 4320 K, 0.401 eV, and −5.24% K−1, respectively for these Mn‐Co‐Ni‐O nanoceramic microspheres. Furthermore, the formation mechanism of uncalcined Mn‐Co‐Ni‐O nanocrystallines and an analysis of the TSS procedure of the nanoceramic microspheres are discussed.
Sustainability design of concrete structures
Authors: Sakai Koji , Shibata Toshio , Kasuga Akio , Nakamura Hikaru
Published: June 2016

Concrete became the most used material on Earth over 200 years following the invention of modern cement. The design concept has undergone a transition from the allowable stress design method, limit state design method, and to the performance‐based design method, in response to the evolution of materials, sophistication of experimental facilities, and advancement of computation skills. From the issues on resources and energy depletion, global warming, and resilience etc., it is necessary to create a new design framework taking into consideration the required performance beyond the conventional concept, in order to construct infrastructure and buildings in a more rational way. In other words, one should construct a design system which sets the continued existence of the diverse and rich global environment as its most important criterion of value. In this paper, the authors review the design and technology system developed in the past and discusses it based on the above‐mentioned new viewpoint, while constructing and presenting a new design system for concrete structures, focusing mainly on the concept of sustainability which is regarded as the most important in achieving conservation of the Earth's rich resources as well as sound socioeconomic activities of humankind in the future, and discusses its feasibility.
Sympathetic inrush current in a transformer and a method for its identification
Authors: Qi Xuanwei , Yin Xianggen , Zhang Zhe
Published: June 2016

This paper studies the sympathetic interaction between transformers. The influencing factors of the sympathetic inrush current, including the system impedance, closing angle and the initial remnant flux of the added transformer, the system voltage, and the neutral grounding mode of the transformers, are analyzed in detail through dynamic simulation. Based on this, a method for identifying the sympathetic inrush current is proposed based on the essential curve feature of the magnetizing currents of the transformers during the sympathetic interaction, taking advantage of the information sharing between substations. The results from dynamic simulation and field‐recorded data show the validity of the proposed method. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Distributed opportunistic scheduling for MIMO underlay cognitive radio networks
Authors: El Tanab Manal , Hamouda Walaa , Fahmy Yasmine
Published: June 2016

Cognitive radio networks have emerged to improve the utilization of the scarce spectrum. In this paper, we propose a distributed resource allocation algorithm that allocates resources opportunistically to the secondary users in a multiple‐input multiple‐output environment. In order to reduce the complexity and cost, antenna selection schemes are employed to allow the secondary communication using a single radio frequency chain. The proposed algorithm is proved theoretically and using simulations, to give a performance very close to that of a centralized one with lower delay and overhead. Furthermore, we introduce two techniques for the proposed algorithm based on the allowable data rates referred to as limited and maximum rates. We derive closed‐form expression for the consumed power and tight upper bounds for the average throughput achieved by each technique. A comparison between the proposed techniques is also provided. Both simulations and analytical results show that the proposed algorithm achieves high throughput with low complexity. Moreover, the results show that the tightness of the bounds improves with the diversity order. Finally, the proposed techniques are compared with two suggested random schemes to investigate their effectiveness. Copyright © 2016 John Wiley & Sons, Ltd.
Calculations of magnetically induced current densities: theory and applications
Authors: Sundholm Dage , Fliegl Heike , Berger Raphael J.F.
Published: June 2016

A review of computational studies of magnetically induced current density susceptibilities in molecules and their relation to experiments is presented. The history of the investigation of magnetically induced current densities and ring currents in molecules is briefly covered. The theoretical development of relativistic and nonrelativistic computational approaches for computing current densities in closed‐shell and open‐shell molecules is discussed and different state of the art methods to interpret calculated current densities are reviewed. Numerical integration approaches to assess global, semilocal, and local aromatic properties of multiring molecules are presented and demonstrated on free‐base trans‐porphyrin. We show that numerical integration of the current density combined with guiding visualization techniques of the current flow is a powerful tool for studies of the aromatic character of complicated molecular structures such as annelated aromatic and antiaromatic rings. Representative applications are reported illustrating the importance of careful current density studies for organic and inorganic chemistry. The applications include calculations of current densities and current strengths for aromatic, antiaromatic, and nonaromatic molecules of different kind. Current densities in spherical, cylindrical, tetrahedral, toroidal, and Möbius‐twisted molecules are discussed. The aromatic character, current pathways, and current strengths of porphyrins are briefly highlighted. Aromatic properties of inorganic molecules are assessed based on current density calculations. Current strengths as a noninvasive tool to determine strengths of hydrogen bonds are discussed. WIREs Comput Mol Sci 2016, 6:639–678. doi: 10.1002/wcms.1270

This article is categorized under:

Structure and Mechanism > Molecular Structures

Electronic Structure Theory > Ab Initio Electronic Structure Methods

Electronic Structure Theory > Density Functional Theory
Synthesis of a Series of Anionic Surfactants Derived from NP and their Properties as Emulsifiers for Reducing Viscosity of Highly Viscous Oil via Formation of O/W Emulsions
Authors: Bao Lei , Wang Hanwei , Wu Yongbin , Li Xingmin , Qiao Weihong
Published: June 2016

A series of alkyl phenol polyoxyethylene glycidyl ether (NP‐n‐O) and alkyl phenol polyoxyethylene ether hydroxypropyl sulfonate (NP‐n‐S) surfactants was synthesized to explore emulsification viscosity reduction. The optimum sulfonation conditions were obtained through orthogonal experiments, the ratio of alkyl phenol polyoxyethylene glycidyl ether and sodium bisulfite 1:1.5, 100 °C, and 6 h. The effects of concentrations of the synthesized surfactants, pH values, emulsifying temperature (40 and 60 °C) and water content on emulsification viscosity reduction and the stability of the emulsion to Venezuela’s Orinoco heavy oil were investigated. The water diversion ratio of emulsion at the reservoir temperature (55 °C) in 30 days was taken as an index, the results show that under the conditions of a temperature of 40 °C, an oil/water ratio of 7:3 and a surfactant NP‐4‐S concentration of 0.5 %, emulsions can be formed with a viscosity reduction rate reaching up to 99.69 % and with a water diversion ratio in 30 days reaching 9.38 %; while at 60 °C and an oil/water ratio of 7:3, at an NP‐4‐S concentration of 1 %, the viscosity reduction rate can reach 99.55 % and water diversion ratio is merely 4.23 % in 30 days. The mixture of NP‐n‐S, xanthan gum and cocamidopropyl dimethylamine oxide (CAO‐30) at suitable concentration can greatly improve the emulsification viscosity reduction and emulsion stability, which gives an emulsion viscosity rate of over 98 %. Moreover, the emulsion can be stable for at least 30 days without water emerging.
Mental health, migration stressors and suicidal ideation among Latino immigrants in Spain and the United States
Authors: Fortuna L.R. , Álvarez K. , Ramos Ortiz Z. , Wang Y. , Mozo Alegría X. , Cook B.L. , Alegría M.
Published: June 2016

Background

Immigration stress appears to augment the risk for suicide behaviors for Latinos. Yet, specific risk factors that contribute to suicidal ideation (SI) among diverse Latino immigrant populations are not well established.

Methods

Data were collected in Boston, Madrid and Barcelona using a screening battery assessing mental health, substance abuse risk, trauma exposure, demographics, and sociocultural factors. Prevalence rates of lifetime and 30-day SI were compared across sites. Logistic regression modeling was used to identify sociodemographic, clinical, and sociocultural-contextual factors associated with 30-day SI.

Results

Five hundred and sixty-seven Latino patients from primary care, behavioral health and HIV clinics and community agencies participated. Rates of lifetime SI ranged from 29–35%; rates for 30-day SI were 21–23%. Rates of SI were not statistically different between sites. Factors associated with SI included exposure to discrimination, lower ethnic identity, elevated family conflict, and low sense of belonging (P< 0.01). In the adjusted model, higher scores on depression, posttraumatic stress disorder, and trauma exposure were significantly associated with 30-day SI (OR = 1.14, 1.04, and 7.76, respectively). Greater number of years living in the host country was significantly associated with increased odds of having SI (OR = 2.22) while having citizenship status was associated with lower odds (OR = 0.45).

Conclusion

Latinos suffering depression, trauma exposure, and immigration stressors are more likely to experience SI. Despite differences in country of origin, education, and other demographic factors between countries, rates of SI did not differ. Recommendations for prevention and clinical practice for addressing suicidal ideation risk among Latino immigrants are discussed.
CFD analysis of hover performance of rotors at full- and model-scale conditions
Authors: Barakos G.N. , Jimenez Garcia A.
Published: June 2016

Analysis of the performance of a 1/4.71 model-scale and full-scale Sikorsky S-76 main rotor in hover is presented using the multi-block computational fluid dynamics (CFD) solver of Glasgow University. For the model-scale blade, three different tip shapes were compared for a range of collective pitch and tip Mach numbers. It was found that the anhedral tip provided the highest Figure of Merit. Rigid and elastic full-scale S-76 rotor blades were investigated using a loosely coupled CFD/Computational Structural Dynamics (CSD) method. Results showed that aeroelastic effects were more significant for high thrust cases. Finally, an acoustic study was performed in the tip-path-plane of both rotors, showing good agreement in the thickness and loading noise with the theory. For the anhedral tip of the model-scale blade, a reduction of 5% of the noise level was predicted. The overall good agreement with the theory and experimental data demonstrated the capability of the present CFD method to predict rotor flows accurately.
ON THE INTERFACE BETWEEN OPTIMAL PERIODIC AND CONTINUOUS DIVIDEND STRATEGIES IN THE PRESENCE OF TRANSACTION COSTS
Authors: Avanzi Benjamin , Tu Vincent , Wong Bernard
Published: June 2016

In the classical optimal dividends problem, dividend decisions are allowed to be made at any point in time — according to acontinuousstrategy. Depending on the surplus process that is considered and whether dividend payouts are bounded or not, optimal strategies are generally of a band, barrier or threshold type. In reality, while surpluses change continuously, dividends are generally paid on a periodic basis. Because of this, the actuarial literature has recently considered strategies where dividends are only allowed to be distributed at (random) discrete times — according to aperiodicstrategy.

In this paper, we focus on the Brownian risk model. In this context, theoptimalcontinuous and periodic strategies have previously been shown (independently of one another) to be of barrier type. For the first time, we consider a model where both strategies are used. In such ahybridstrategy, decisions are allowed to be made either at any time (continuously), or periodically at a lower cost. This proves optimal in some cases. We also determine under which combination of parameters a pure continuous, pure periodic or hybrid (including both continuous and periodic dividend payments) barrier strategy is optimal. Interestingly, the hybrid strategy lies in-between periodic and continuous strategies, which provides some interesting insights. Results are illustrated.
Evaluation of a Healthcare-Associated Urinary Tract Infection Combination Antibiogram
Authors: Wick Jenna , Beaulac Kirthana , Doron Shira
Published: June 2016

We created a 2013 combination antibiogram of healthcare-associated urinary tract infection. The 2013 antibiogram–determined regimen was evaluated in a 2014 cohort who had received empirical therapy. The regimen was statistically more likely to represent adequate treatment than actual prescriptions. A customized antibiogram may guide empirical therapy for specific patients.

Infect Control Hosp Epidemiol 2016;37:1101–1104
Brain Ways: Meynert, Bachelard and the Material Imagination of the Inner Life
Authors: Phelps Scott
Published: June 2016

The Austrian psychiatrist Theodor Meynert’s anatomical theories of the brain and nerves are laden with metaphorical imagery, ranging from the colonies of empire to the tentacles of jellyfish. This paper analyses among Meynert’s earliest works a different set of less obvious metaphors, namely, the fibres, threads, branches and paths used to elaborate the brain’s interior. I argue that these metaphors of material, or what the philosopher Gaston Bachelard called ‘material images’, helped Meynert not only to imaginatively extend the tracts of fibrous tissue inside the brain but to insinuate their function as pathways co-extensive with the mind. Above all, with reference to Bachelard’s study of the material imagination, I argue that Meynert helped entrench the historical intuition that the mind, whatever it was, consisted of some interiority – one which came to be increasingly articulated through the fibrous confines of the brain.
How Face-to-Face Interviews and Cognitive Skill Affect Item Non-Response: A Randomized Experiment Assigning Mode of Interview
Authors: Gooch Andrew , Vavreck Lynn
Published: June 2016

Technology and the decreased cost of survey research have made it possible for researchers to collect data using new and varied modes of interview. These data are often analyzed as if they were generated using similar processes, but the modes of interview may produce differences in response simply due to the presence or absence of an interviewer. In this paper, we explore the differences in item non-response that result from different modes of interview and find that mode makes a difference. The data are from an experiment in which we randomly assigned an adult population to an in-person or self-completed surveyaftersubjects agreed to participate in a short poll. For nearly every topic and format of question, we find less item non-response in the self-complete mode. Furthermore, we find the difference across modes in non-response is exacerbated for respondents with low levels of cognitive abilities. Moving from high to low levels of cognitive ability, an otherwise average respondent can be up to six times more likely to say “don’t know” in a face-to-face interview than in a self-completed survey, depending on the type of question.
Provenance of volcaniclastic beach sand in a magmatic-arc setting: an example from Lipari island (Aeolian archipelago, Tyrrhenian Sea)
Authors: MORRONE CONSUELE , DE ROSA ROSANNA , LE PERA EMILIA , MARSAGLIA KATHLEEN M.
Published: June 2016

Lipari, an active volcanic island in the Aeolian magmatic arc, is an excellent area to determine the effects of multiple source lithology, climate, weathering, transport and depositional environment on epiclastic sand composition. Volcaniclastic sand samples from 12 modern beaches were petrographically characterized using the Gazzi–Dickinson method, and the proportions of source rocks in combination with topography in associated coastal drainage basins were quantified using GIS. Several types of bedrock in the 12 drainage basins that are the likely prominent sources for sand at each sampled beach were recognized, and divided into two categories of provenance lithotypes: lavas and pyroclastic rocks ranging in composition from basaltic andesitic, to andesitic, to rhyolitic. Volcanic lithic fragments from Lipari beach sand consist of colourless and black glassy volcanic fragments with lathwork, felsitic, vitric and microlitic textures. Moreover, high amounts of detrital less durable minerals, such as pyroxene, olivine and Fe oxides, illustrate how the analysed sands preserve the source rock(s) provenance signals. Applying the concept of Sand Generation Index we see that these lithotypes have different propensities to create detritus, in terms of both grain-size and composition. Clastic contribution from pyroclastic rock outcrops such as pumice is not found in the size ranges studied, suggesting that these pumiceous source rocks probably only produce gravel or very fine sand and silt. This finding has implications for the stratigraphic record because pumice clasts, ranging from medium to fine grain-size, could be underrepresented in older volcaniclastic deposits and overrepresented in other size fractions.
Differences between root traits of early- and late-successional trees influence below-ground competition and seedling establishment
Authors: Zangaro Waldemar , Lescano Luis Eduardo Azevedo Marques , Matsuura Enio Massao , Rondina Artur Berbel Lirio , Nogueira Marco Antonio
Published: June 2016

The competitive influence of the root system of the exotic grassUrochloa brizanthaand the widespread forbLeonotis nepetifoliaon the emergence, survival and early growth of the seedlings of eight tropical heliophilous herbaceous species, six early-successional woody species and five late-successional woody species from Brazil, grown in 3500-cm3pots and in greenhouse without light restriction were assessed. The density of fine-root systems produced by the forb and the grass in pots were 6.8 cm cm−3soil and 48.1 cm cm−3soil, respectively. Seedlings survival of the heliophilous herbaceous, early- and late-successional woody species were 86%, 70% and 100% in presence of the forb root system and 12%, 14% and 100% in competition with grass root system, respectively. The competitive pressure applied by the grass root system on seedling growth of the heliophilous herbaceous, early- and late-successional woody species were 2.4, 1.9 and 1.4 times greater than the forb root system. Total root length of the heliophilous herbaceous, early- and late-successional woody species grown without competitors were 13, 33 and 5 times greater than in competition with forb, and were 66, 54 and 6 times greater than in competition with grass root system, respectively. The averages of fine-root diameter of plants grown without competitors were 209 μm for the heliophilous herbaceous, 281 μm for early-successional trees and 382 μm for late-successional trees. The root system of the forb did not avoid seedling establishment of most plant species, but the grass root system hampered more the establishment of heliophilous herbaceous and early-successional woody species than the seedling establishment of late-successional woody species. The different density of root systems produced in soil by the forb and the grass, and the distinct root traits (e.g. root diameter and root tissue density) of the early- and late-successional plant species can explain the differences in the establishment of seedlings of plant species belonging to different groups of tropical succession when exposed to below-ground competition.
Interaction Forces Between Two Ships During Underway Replenishment
Authors: Miller Anna
Published: June 2016

Knowledge of forces and yaw moments which exist between a pair of vessels moving parallel to each other is crucial to the design of their automatic motion control system. Studies involving measurements of forces and moments occurring between a pair of ships were undertaken. The research was carried out on the basis of two real floating training ship models made at 1:24 scale in real conditions on the Silm Lake in Ilawa Kamionka. As a result, suction forces and yaw moments occurring between the pair of vessels calculated according to semi-empirical formula were verified. It was found that the process of overtaking and parallel motion (which is a quasi-stationary motion) could not be modelled in the same way. Nevertheless, the results confirmed the presence of forces and moments with values similar to those in the catch-up and parallel motion phases during the ships’ overtaking manoeuvre. Thanks to this confirmation, it was possible to use the results of the analytical calculation for the catch-up phase during design of the ships' parallel motion automatic control system.
Class Bias in Voter Turnout, Representation, and Income Inequality
Authors: Franko William W. , Kelly Nathan J. , Witko Christopher
Published: June 2016

The mass franchise led to more responsive government and a more equitable distribution of resources in the United States and other democracies. Recently in America, however, voter participation has been low and increasingly biased toward the wealthy. We investigate whether this electoral “class bias” shapes government ideology, the substance of economic policy, and distributional outcomes, thereby shedding light on both the old question of whether who votes matters and the newer question of how politics has contributed to growing income inequality. Because both lower and upper income groups try to use their resources to mobilize their supporters and demobilize their opponents, we argue that variation in class bias in turnout is a good indicator of the balance of power between upper and lower income groups. And because lower income voters favor more liberal governments and economic policies we expect that less class bias will be associated with these outcomes and a more equal income distribution. Our analysis of data from the U.S. states confirms that class bias matters for these outcomes.
The Policyscape and the Challenges of Contemporary Politics to Policy Maintenance
Authors: Mettler Suzanne
Published: June 2016

Contemporary political life takes place amid a “policyscape,” a landscape densely laden with policies created in the past that have themselves become established institutions, bearing consequences for governing operations, the policy agenda, and political behavior. Far from being static, policies often develop over time in ways that could not have been foreseen by their creators, due to dynamics they themselves generate, including design effects, unintended consequences, and lateral effects. Owing to such dynamics, existing policies require upkeep and maintenance if they are to continue to function well. The extent to which lawmakers engage effectively in such work varies, however, depending on the fit between the demands of the policyscape and the attributes of the historical political context. Bipartisan reform efforts occurred in many policy areas as recently as the early 1990s. More recently, partisan polarization and other developments have undermined such political capacity, leaving numerous policies untended for long periods and in many instances, even formal reauthorization long overdue. A cursory overview of policies associated with Americans’ top 20 policy priorities reveals that more than half are subject to deferred maintenance. The mismatch between the demands of the policyscape and the character of contemporary politics imperils effective democratic governance.
How Employers Recruit Their Workers into Politics—And Why Political Scientists Should Care
Authors: Hertel-Fernandez Alexander
Published: June 2016

In the wake of theCitizens UnitedSupreme Court decision, many American private-sector employers now have the legal right to recruit their workers into politics and to fire or discipline employees who refuse to participate. How many firms and workers are engaged in this kind of political recruitment and why? And how have the opportunities for the political recruitment of workers by their employers changed over time? Drawing on national surveys of top corporate managers and workers, as well as a review of the legal literature, I provide initial answers to these questions and illustrate the implications of employer political recruitment for a range of substantive and normative issues in American politics. My findings invite further research and discussion about this feature of the American workplace and its effects on politics and policy.
MTHFD1 controls DNA methylation in Arabidopsis
Authors: Groth Martin , Moissiard Guillaume , Wirtz Markus , Wang Haifeng , Garcia-Salinas Carolina , Ramos-Parra Perla A. , Bischof Sylvain , Feng Suhua , Cokus Shawn J. , John Amala , Smith Danielle C. , Zhai Jixian , Hale Christopher J. , Long Jeff A. , Hell Ruediger , Díaz de la Garza Rocío I. , Jacobsen Steven E.
Published: June 2016

DNA methylation is an epigenetic mechanism that has important functions in transcriptional silencing and is associated with repressive histone methylation (H3K9me). To further investigate silencing mechanisms, we screened a mutagenized Arabidopsis thaliana population for expression of SDCpro-GFP, redundantly controlled by DNA methyltransferases DRM2 and CMT3. Here, we identify the hypomorphic mutant mthfd1-1, carrying a mutation (R175Q) in the cytoplasmic bifunctional methylenetetrahydrofolate dehydrogenase/methenyltetrahydrofolate cyclohydrolase (MTHFD1). Decreased levels of oxidized tetrahydrofolates in mthfd1-1 and lethality of loss-of-function demonstrate the essential enzymatic role of MTHFD1 in Arabidopsis. Accumulation of homocysteine and S-adenosylhomocysteine, genome-wide DNA hypomethylation, loss of H3K9me and transposon derepression indicate that S-adenosylmethionine-dependent transmethylation is inhibited in mthfd1-1. Comparative analysis of DNA methylation revealed that the CMT3 and CMT2 pathways involving positive feedback with H3K9me are mostly affected. Our work highlights the sensitivity of epigenetic networks to one-carbon metabolism due to their common S-adenosylmethionine-dependent transmethylation and has implications for human MTHFD1-associated diseases.
Visualizing the formation of an RNA folding intermediate through a fast highly modular secondary structure switch
Authors: Xue Yi , Gracia Brant , Herschlag Daniel , Russell Rick , Al-Hashimi Hashim M.
Published: June 2016

Intermediates play important roles in RNA folding but can be difficult to characterize when short-lived or not significantly populated. By combining 15N relaxation dispersion NMR with chemical probing, we visualized a fast (kex=k1+k−1≈423 s−1) secondary structural switch directed towards a low-populated (∼3%) partially folded intermediate in tertiary folding of the P5abc subdomain of the ‘Tetrahymena’ group I intron ribozyme. The secondary structure switch changes the base-pairing register across the P5c hairpin, creating a native-like structure, and occurs at rates of more than two orders of magnitude faster than tertiary folding. The switch occurs robustly in the absence of tertiary interactions, Mg2+ or even when the hairpin is excised from the three-way junction. Fast, highly modular secondary structural switches may be quite common during RNA tertiary folding where they may help smoothen the folding landscape by allowing folding to proceed efficiently via additional pathways.
Efficient generation of monoclonal antibodies against peptide in the context of MHCII using magnetic enrichment
Authors: Spanier Justin A. , Frederick Daniel R. , Taylor Justin J. , Heffernan James R. , Kotov Dmitri I. , Martinov Tijana , Osum Kevin C. , Ruggiero Jenna L. , Rust Blake J. , Landry Samuel J. , Jenkins Marc K. , McLachlan James B. , Fife Brian T.
Published: June 2016

Monoclonal antibodies specific for foreign antigens, auto-antigens, allogeneic antigens and tumour neo-antigens in the context of major histocompatibility complex II (MHCII) are highly desirable as novel immunotherapeutics. However, there is no standard protocol for the efficient generation of monoclonal antibodies that recognize peptide in the context of MHCII, and only a limited number of such reagents exist. In this report, we describe an approach for the generation and screening of monoclonal antibodies specific for peptide bound to MHCII. This approach exploits the use of recombinant peptide:MHC monomers as immunogens, and subsequently relies on multimers to pre-screen and magnetically enrich the responding antigen-specific B cells before fusion and validation, thus saving significant time and reagents. Using this method, we have generated two antibodies enabling us to interrogate antigen presentation and T-cell activation. This methodology sets the standard to generate monoclonal antibodies against the peptide–MHCII complexes.
Vacuum Rabi splitting in a plasmonic cavity at the single quantum emitter limit
Authors: Santhosh Kotni , Bitton Ora , Chuntonov Lev , Haran Gilad
Published: June 2016

The strong interaction of individual quantum emitters with resonant cavities is of fundamental interest for understanding light–matter interactions. Plasmonic cavities hold the promise of attaining the strong coupling regime even under ambient conditions and within subdiffraction volumes. Recent experiments revealed strong coupling between individual plasmonic structures and multiple organic molecules; however, strong coupling at the limit of a single quantum emitter has not been reported so far. Here we demonstrate vacuum Rabi splitting, a manifestation of strong coupling, using silver bowtie plasmonic cavities loaded with semiconductor quantum dots (QDs). A transparency dip is observed in the scattering spectra of individual bowties with one to a few QDs, which are directly counted in their gaps. A coupling rate as high as 120 meV is registered even with a single QD, placing the bowtie-QD constructs close to the strong coupling regime. These observations are verified by polarization-dependent experiments and validated by electromagnetic calculations.