bluuebunny/crossref_metadata_2025 huggingface dataset:
Energetically consistent scale‐adaptive stochastic and deterministic energy backscatter schemes for an atmospheric model
Authors: Dwivedi Suneet , Franzke Christian L. E. , Lunkeit Frank
Published: July 2019

Current climate models still suffer from many biases which are partly due to excessive subgrid‐scale dissipation. Here we systematically develop energetically consistent stochastic energy backscatter (SEB) and deterministic energy backscatter (DEB) parametrization schemes. We implement our schemes in a simplified spectral atmospheric General Circulation Model (GCM). It is shown that the SEB scheme performs better than the DEB scheme at low horizontal resolutions (T21 and T31), whereas the performance of both schemes becomes comparable as the resolution increases to T42 when comparing with our reference simulation at T127 resolution. The energy backscatter parametrization schemes improve eddy variability in low‐resolution models and correctly capture the dominant mode of zonal‐mean zonal wind variability. The autocorrelation time‐scale of low‐resolution models is also found to be more consistent with the reference simulation when applying the SEB and DEB parametrizations. Our schemes are scale‐adaptive and computationally efficient.
Markov chain‐based cost‐optimal control charts for health care data
Authors: Dobi Balázs , Zempléni András
Published: July 2019

Control charts have traditionally been used in industrial statistics but are constantly seeing new areas of application, especially in the age of Industry 4.0. This paper introduces a new method, which is suitable for applications in the health care sector, especially for monitoring the health characteristic of a patient. We adopt a Markov chain‐based approach and develop a method in which not only the shift size (ie, the degradation of the patient's health) can be random, but the effect of the repair (ie, treatment) and time between samplings (ie, visits) too. This means that we do not use many often‐present assumptions that are usually not applicable for medical treatments. The average cost of the protocol, which is determined by the time between samplings and the control limit, can be estimated using the stationary distribution of the Markov chain.

Furthermore, we incorporate the standard deviation of the cost into the optimisation procedure, which is often very important from a process control viewpoint. The sensitivity of the optimal parameters and the resulting average cost and cost standard deviation on different parameter values is investigated. We demonstrate the usefulness of the approach for real‐life data of patients treated in Hungary, namely the monitoring of cholesterol level of patients with cardiovascular event risk. The results showed that the optimal parameters from our approach can be somewhat different from the original medical parameters.
Observer‐based finite‐time output‐feedback controller for DC‐DC buck converters with unknown load variations
Authors: Cheng Yingying , Jin Qingchun , Du Haibo , Xu Yeyuan , Zhu Wenwu , Jiang Congrang
Published: July 2019

The output voltage regulation problem of a DC‐DC buck converter is investigated in this paper via an observer‐based finite‐time output‐feedback control approach. Considering the effects of unknown load variations and the case without current sensor, by using the technique of adding a power integrator and the idea of nonseparation principle, a finite‐time voltage regulation control algorithm via dynamic output feedback is designed. The main feature of the designed observer and controller does not need any load's information. Theoretically, it is proven that the output voltage can reach the desired voltage in a finite time under the proposed controller. The effectiveness of the proposed control method is illustrated by numerical simulations and experimental results.
Gaussian mixture models as automated particle classifiers for fast neutron detectors
Authors: Blair Brenton , Chen Cliff , Glenn Andrew , Kaplan Alan , Ruz Jaime , Simms Lance , Wurtz Ron
Published: July 2019

Pulse shape discrimination (PSD) is the task of classifying electronic pulse shapes for different particle types such as gamma rays and fast neutrons interacting in scintillators and read out by photo sensitive detectors. This field has been limited in its adoption of techniques found in the statistical learning community. Methods initially employed in the 1960s for analog electronic circuitry persist in the current PSD literature describing operations performed on digitized pulses, which are amenable to statistical rigor. Despite vast amounts of data collected at low energy levels, traditional PSD methods are unable to discriminate particles below a certain threshold. In this work, Gaussian mixture models (GMMs) are used as a clustering technique for fast neutron detection in the absence of labeled data. GMMs yield improvements spanning the energy spectrum in a desirably efficient, unsupervised fashion. An extension, the Dirichlet Process GMM, provides further flexibility and classification improvement.
A dynamic CSFICA and feature‐based collision detection method in multichannel space‐based AIS
Authors: Zhang Peixin , Wang Jianxin , Tian Da , Ren Peng
Published: July 2019

To detect message collisions in multichannel spaced‐based automatic identification system (AIS), a dynamic complex symmetric fast independent component analysis (CSFICA) and feature‐based collision detection method is proposed in this paper. A fast and stable blind source separation algorithm, dynamic CSFICA, is utilized to separate signals dynamically and improve the signal‐to‐interference ratio (SIR) in each channel. A frequency and phase offset insensitive feature detection algorithm is used to calculate the test statistics in each channel. The false alarm is suppressed by applying the arithmetic to geometric mean (AGM) method, and test statistics of channels with sufficient signal quality are extracted to detect the preamble. Simulation results show that the proposed algorithm outperforms the reference feature detection algorithm under collision conditions and is insensitive to the SIR. The proposed algorithm is more resistant to false alarm caused by signal (FAS) than the differential correlation (DC) algorithm.
Organizational design choices of high‐tech startups: How middle management drives innovation performance
Authors: Grimpe Christoph , Murmann Martin , Sofka Wolfgang
Published: July 2019

Research Summary

Innovative products and services are the inspiration for many startups. However, founders find that the management of existing operations competes with the attention that they can devote to innovation. We investigate whether and how establishing a middle management level frees up attention for innovation when firms are newly started. We argue that middle management is positively related to introducing product innovations and that the effect is stronger when founders have larger stocks of pre‐existing knowledge and when the startup's industry provides more innovation opportunities. These hypotheses are supported by an analysis of 2,431 German high‐tech startups founded between 2005 and 2012.

Managerial Summary

Most high‐tech entrepreneurs acknowledge that an overload of managerial tasks keeps them from advancing innovation in their startups. However, they are often times reluctant to introduce middle management because of a fear that the resulting bureaucratization will stifle innovation. Our study shows that these fears are not justified. Instead, we find for 2,431 high‐tech startups in Germany that startups with middle managers are significantly more innovative than those without. While middle managers might be a roadblock for innovation in large firms, startups benefit from having them. Founders are the central decision makers in startups and can easily be overburdened with management tasks. Middle managers can alleviate parts of this workload and allow founders to focus on creating innovative products and services.
First‐principles study of the atomic structures, electronic properties, and surface stability of BaTiO3 (001) and (011) surfaces
Authors: Zhong Mi , Zeng Wei , Liu Fu‐Sheng , Tang Bin , Liu Qi‐Jun
Published: July 2019

The atomic structures, electronic properties, and surface stability of (001) and (011) surfaces of BaTiO3 are studied by first‐principles calculations. Four differently terminated BaTiO3 surfaces are considered in this study, including (001)‐BaO, (001)‐TiO2, (011)‐BaTiO, and (011)‐O2 terminations. The relaxations and rumplings are calculated and discussed, finding that the first layer relaxes inwards, while the second layer relaxes outwards for (001) and (110) surfaces. The data obtained for electronic properties show that O2p states in (001)‐BaO/(001)‐TiO2 termination shift to the lower/higher energy region, leading to a wide/narrow band gap. And the new produced surface states are observed in (011) surface terminations, which is mainly attributed to the supplied electrons from outermost surface atoms, even O atoms are oxidized. Furthermore, the (001) surface of BaTiO3 is found to be more stable than the (011) surface according to the predicted surface energy which is 0.86 and 2.92 J/m2 for (001) and (011) surfaces, respectively. Of which, BaO termination is predicted to be more likely to cleavage from the (001) direction than the TiO2 termination is.
A new perspective on loss to follow‐up in failure time and life history studies
Authors: Lawless Jerald F. , Cook Richard J.
Published: July 2019

A framework is proposed for the joint modeling of life history and loss to follow‐up (LTF) processes in cohort studies. This framework provides a basis for discussing independence conditions for LTF and censoring and examining the implications of dependent LTF. We consider failure time and more general life history processes. The joint models are based on multistate processes with expanded state spaces encompassing both the life history and LTF processes. Tracing studies are discussed as a means of investigating the presence of dependent censoring and providing valid estimates of transition intensities and state occupancy probabilities. Simulation studies and an illustration based on a cohort of individuals with systemic lupus erythematosus demonstrate the usefulness and properties of the proposed methods.
Self‐Assembled Metalloporphyrins–Magnesium Phosphate Hybrid Spheres as Efficient Catalysts for Cycloaddition of Carbon Dioxide
Authors: Gan Tao , Zhang Hao , Liu Yifei , He Qian , Zhang Ying , He Xiaohui , Ji Hongbing
Published: July 2019

Due to the unique microstructure and superior catalytic properties, organic‐inorganic hybrid materials attract extensive attention. Herein, we report a facile coprecipitation method for the fabrication of metalloporphyrin–metal phosphate salt hybrid spheres, and the cycloaddition of carbon dioxide with epoxides is employed as probe reaction to evaluate the catalytic performance of our as‐synthesized catalysts. The hybrid spheres composed of meso‐tetra‐(4‐N‐pyridyl) zinc porphyrin (ZnTPyP)–magnesium phosphate exhibited superior catalytic performance, and the conversion was much higher than that of individual ZnTPyP and magnesium phosphate, probably because of the acid‐base synergistic effect. Meanwhile, the spheres showed excellent stability during the circulation experiments as well as compatibility with a wide scope of substrates. This work provides a valuable approach for the preparation of novel and efficient heterogeneous catalytic composites.
Citrate Stabilized Au‐FexOy Nanocomposites for Variable Exchange Bias, Catalytic Properties and Reversible Interaction with Doxorubicin
Authors: Lone Shahbaz Ahmad , Sanyal Prabuddha , Das Pintu , Sadhu Kalyan K.
Published: July 2019

Exchange bias effect in Au‐FexOy nanocomposites, prepared with regulated Au:Fe content, has been controlled using the variable iron content and the composition of FexOy. A green synthetic route has been adapted at room temperature in aqueous medium for such Au−Fe oxide nanocomposites. Diversity in FexOy compositions has been achieved through Au(III) reduction by Fe powder to obtain Au‐FexOy nanocomposites in presence of gold nanoparticles as seed and threshold amount of sodium citrate as stabilizing agent. The exchange bias effect in selective Au‐FexOy nanocomposites (5Fe, 6Fe, 7Fe and 9Fe) arises from the ferromagnetic‐antiferromagnetic (FM‐AFM) interaction between Fe3O4 and α‐Fe2O3 present in the samples. A theoretical model is used to explain the variation of the exchange bias, coercivity and magnetization for the different samples at various temperatures. These Au‐FexOy nanocomposites have been compared in terms of their catalytic activities for nitroarene reductions and reversible surface interaction with cancer drug doxorubicin.
A systematic literature review of software effort prediction using machine learning methods
Authors: Ali Asad , Gravino Carmine
Published: July 2019

Machine learning (ML) techniques have been widely investigated for building prediction models, able to estimate software development effort as well as to improve the accuracy of other estimation techniques. The objective of this paper is to systematically review the recent studies which used and discussed the software effort estimation models built using ML techniques. The performed literature review is based on the empirical studies published in the time period of January 1991 to December 2017, by employing widely used guidelines. The review has selected a total of 75 primary studies after the careful filtering of inclusion/exclusion and quality assessment criteria. The performed analysis reveals that artificial neural network (ANN) as ML model, NASA as dataset, and mean magnitude of relative error (MMRE) as accuracy measure are widely used in the selected studies. ANN and support vector machine (SVM) are the two techniques which have outperformed other ML techniques in more studies. Regression techniques are the mostly used among the non‐ML techniques, which outperformed other ML techniques in about 19 studies. Moreover, SVM and regression techniques in combination are characterized by better predictions when compared with other ML and non‐ML techniques.
Highly Transparent Organic Solar Cells with All‐Near‐Infrared Photoactive Materials
Authors: Xie Yuanpeng , Xia Ruoxi , Li Tengfei , Ye Linglong , Zhan Xiaowei , Yip Hin‐Lap , Sun Yanming
Published: July 2019

Transparent organic photovoltaics are identified as important components for building‐integrated photovoltaics and smart window technologies. In this work, highly transparent organic solar cells (T‐OSCs) based on all‐near‐infrared (NIR) harvesting materials (optical bandgap, < 1.4 eV) are first fabricated. Both donor and acceptor materials used in T‐OSCs exhibit great transparency in the visible region. After combining MoO3/Ag or MoO3/Ag/MoO3 transparent electrode, T‐OSCs show excellent visible light transmittance (VLT) of 52–61.5% with power conversion efficiencies of 3.5–4.2%. As far as it is known, this all‐NIR active layer represents the most visible transparent donor–acceptor combination in OSCs. In addition to high VLT, T‐OSCs have great aesthetic value, good color‐rendering index (CRI > 90), and high light energy utilization properties. This work highlights great potential of NIR photoactive materials for T‐OSCs.
Sequential Processing: Crystallization of Ultrasmooth FA1–xMAxPbI3 Perovskite Layers for Highly Efficient and Stable Planar Solar Cells
Authors: Wu Ya-Han , Ding Yong , Liu Xiao-Yan , Pan Xu , Wu Ji-Huai , Dai Song-Yuan
Published: July 2019

Planar perovskite solar cells (PSCs) are promising photovoltaic devices accompanied with the obvious advantages of easy fabrication and scalability. To achieve highly efficient and stable PSCs, the morphology control of perovskite crystallization is crucial. Herein, a novel method toward obtaining high‐quality FA1–xMAxPbI3 films by spin coating methylammonium chloride (MACl) and chlorobenzene (CB) in different sequential processes on the top of substrates is proposed. Controlling the nucleation process is beneficial for the formation of a homogeneous nucleus at the nucleation stage, leading to highly ordered seed crystals and an ultrasmooth perovskite film. As determined by photoluminescence and time‐resolved photoluminescence spectroscopy, the defects and the associated charge recombination are notably reduced by the high crystalline quality of perovskite film. Finally, a champion power conversion efficiency (PCE) of 18.57% is achieved and 91% of the initial PCE is retained after 500 h. The devices are stored in an ambient condition with 20% relative humidity (RH) at 30 °C in the dark.
Decoupling and analysis of the deformation of flanged reinforced concrete shear walls
Authors: Wang Bin , Shi Qing‐Xuan , Cai Wen‐Zhe
Published: July 2019

Compared with rectangular walls, a relatively large proportion of shear deformations are expected for flanged walls due to their larger flexural capacity. As few well‐documented experimental data are available to assess the attributes of the various deformation components of flanged walls, the feasibility of using established models to predict the deformation capacity of flanged walls is debatable. This study presents experimental results for three large‐scale T‐shaped reinforced concrete walls under cyclic loading to examine the relative contributions of flexural, shear, and sliding deformations to lateral displacement. By using a high‐precision and noninterference measurement method based on particle image velocimetry, the deformation components were decoupled to investigate the variation in each deformation component with the total deformation corresponding to the damage evolution process. For flexure‐dominant T‐shaped walls, the ratio of shear‐to‐total deformations in the plastic hinge region slowly increases over the entire plastic range, whereas the ratio of shear‐to‐total top displacements remains approximately constant. When predicting the deformation capacity of flanged walls, shear deformations but not the contribution of sliding deformations should be considered. Based on the proportional relationship between shear strain and curvature, a simple model for estimating the shear deformations of flexure‐dominant flanged walls is proposed.
“In Search of Peace”: Refugee Experiences in Children's Literature
Authors: A. Ward Natalia , N. Warren Amber
Published: July 2019

The authors closely analyzed 45 children's books featuring characters with refugee backgrounds that had been published since 2013. With the concept of culturally sustaining pedagogy underpinning the review, analysis revealed that these texts are rich and detailed, providing a starting point for discussing the global refugee crisis with students, but they occasionally fall short in providing complex, multidimensional representations of characters’ lives and experiences. A majority of the texts analyzed focus on the journey in search of a safe place to live, whereas very few focus on the complexity of making a life in a new place. The findings highlight the importance of identifying texts that provide complexity, dimension, and specificity in depicting experiences of refugee‐background characters across settings. Opening classrooms to texts about the diversity of refugee experiences invites teachers and their students to critically explore the important global issues of migration, equity, and ways of being human.
Reduced coronary flow velocity reserve in women with previous pre‐eclampsia: link to increased cardiovascular disease risk
Authors: Clemmensen T. S. , Christensen M. , Løgstrup B. B. , Kronborg C. J. S. , Knudsen U. B.
Published: July 2019

Objectives

To evaluate differences in coronary microvascular function approximately 12 years after delivery between women who had had early‐ (EO‐PE) or late‐ (LO‐PE) onset pre‐eclampsia and those who had had a normotensive pregnancy, and to assess the relationship between microvascular function and myocardial deformation at follow‐up in these women.

Methods

This was a case–control study of 88 women who had delivered at the Department of Gynecology and Obstetrics, Randers Regional Hospital, Randers, Denmark, between 1998 and 2008. Coronary flow velocity reserve (CFVR) was assessed by Doppler echocardiography approximately 12 years after delivery. Women were grouped according to whether the pregnancy had been complicated by EO‐PE (n = 29) or LO‐PE (n = 20), or had been normotensive (controls) (n = 39). Study groups were matched for maternal age and time since delivery. CFVR at follow‐up was compared between the study groups. Regression analysis was used to assess the association between gestational age at onset of PE and CFVR. The association between left ventricular global longitudinal strain (LV‐GLS) and CFVR at follow‐up was also evaluated.

Results

Resting coronary flow velocity assessed 12 years after delivery was comparable between the study groups (P = 0.55), whereas peak hyperemic flow velocity was significantly lower in the EO‐PE group than in the LO‐PE group (P < 0.01) and controls (P < 0.0001). As such, mean CFVR at follow‐up was significantly lower in the EO‐PE group than in the LO‐PE group (P < 0.01) and controls (P < 0.0001). CFVR was < 2.5 in 48% of women in the EO‐PE group, 25% of those in the LO‐PE group and 8% of controls (P < 0.01). There was a significant positive association between gestational age at diagnosis of PE and CFVR at 12‐year follow‐up (β1 = 1.8 (95% CI, 0.8–2.9); P < 0.01). This relationship remained significant after adjustment for cardiovascular risk factors, namely mean arterial blood pressure, glycated hemoglobin level, body mass index, low‐density lipoprotein cholesterol level and smoking status (P < 0.05). There was a significant association between LV‐GLS and CFVR in women who had had PE (β1 = –1.5 (95% CI, –2.2 to –0.9); R2 = 0.33, P < 0.0001).

Conclusions

Low gestational age at onset of PE, both as a continuous variable and when categorized as early onset, was associated with decreased CFVR 12 years after delivery. Nearly 50% of women who had had EO‐PE had CFVR < 2.5 at follow‐up. Reduced CFVR in women who had had PE was associated with subclinical myocardial dysfunction in terms of reduced LV‐GLS. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.
Spatial variability in the isotopic composition of water in small catchments and its effect on hydrograph separation
Authors: Penna Daniele , van Meerveld H. J. (Ilja)
Published: July 2019

Hydrograph separation is a widely applied technique that uses the stable isotopes of water (2H and 18O) or other tracers to quantify the contribution of different water sources to streamflow. For its successful application it is critical to adequately characterize these sources (end‐members). In most small catchment studies, water samples are collected from end‐members at one or a few locations that are assumed to be representative for the entire catchment. We tested this assumption by reviewing 148 papers that used the stable isotopes of water to investigate hydrological processes in catchments up to 10 km2. We assessed the typical spatial variability in the isotopic composition of different hydrological compartments when they were sampled at five or more locations across a catchment. The median reported spatial variability was largest for snowmelt and soil water, followed by throughfall and shallow groundwater. To determine how this spatial variability might affect isotope‐based hydrograph separation results, we used three‐component hydrograph separation for two real rainfall‐runoff events and a synthetic rainfall‐runoff event and adjusted the isotopic composition of the end‐members (throughfall, soil water, and shallow groundwater) by the median observed spatial variability. The estimated maximum contributions of the three components differed by up to 26% from the reference scenario. This suggests that caution is needed when interpreting hydrograph separation results if they are based on samples taken at one or only a few locations. Above all, these results show that the assumption of negligible spatial variability may not be valid for small catchments.

This article is categorized under:

Science of Water > Hydrological Processes

Science of Water > Methods
Significant effect of compositional grading on SAGD performance in a fractured carbonate heavy oil reservoir
Authors: Ghalenavi Hossein , Norouzi-Apourvari Saeid , Schaffie Mahin , Ranjbar Mohammad
Published: July 2019

In reservoir simulation, the fluid composition is usually assumed uniform for the whole reservoir, while in many reservoirs, oil and gas composition changes with depth. This phenomenon which is known as compositional grading could be significant in heavy and super heavy oil reservoirs. In these reservoirs, biodegradation and asphaltene precipitation are considered as the main reasons behind this phenomenon. Compositional grading in heavy oil reservoirs could affect fluid viscosity and vaporizing–condensing mechanism in steam-assisted gravity drainage (SAGD) operations. In this paper, through a simulation study, one of the Iranian heavy oil reservoirs which have a significant compositional grading was selected to investigate the effect of compositional grading on the performance of simulated SAGD method. The reservoir is a fractured carbonate reservoir, and its compositional grading is maintained because of the lack of convection inside the reservoir. To verify the importance of compositional grading, the performance results of the SAGD method for compositional grading case were compared with that of uniform composition case. The result showed that ignoring compositional grading would lead to underestimation of ultimate recovery in the fractured model. The study of SAGD process in a non-fractured reservoir model showed that considering compositional grading has an insignificant effect on SAGD performance.
Analysis and optimization of multiple factors influencing fracturing induced stress field
Authors: Guan Bing , Li Shibin , Liu Jiran , Zhang Ligang , Chen Shuangqing
Published: July 2019

The induced stress field caused by hydraulic fracturing plays a key role in controlling the formation characteristics of fractures and is the essential prerequisite for optimal design of fracturing parameters. In order to determine the disturbance range of induced stress field on fracture morphology, the multiple factors analysis and optimization are an important inspect. Setting the induced stress control range (ISCR) as the evaluation objective, it can be defined as the combined response of the peak value of induced stress difference and stress steering distance, taking them as double evaluation indexes. Six uncertain fracture parameters with a reasonable range are used to fit the response of evaluation indexes. Through the finite element numerical simulation method, the induced stress field around the fractures can be calculated and the evaluation indexes are described quantitatively. Applying the multi-factor orthogonal test method, combined the matrix analysis model with the fuzzy comprehensive evaluation model, these fracture parameters are evaluated and optimized. The results show that the influence factors on the ISCR in the descending order are determined as follows: fracture height, fracture net pressure, Poisson’s ratio, maximum and minimum horizontal stress ratio, fracture spacing and its number. According to the multi-factors sensitivity analysis results, the selected levels of different factors are optimized and the combination of parameters optimization is screened out. It provides a theoretical basis to control the reservoir stress field for the optimization of the field fracturing treatment.
Focus on Prenatal Detection of Micrognathia
Authors: Antonakopoulos Nikolaos , Bhide Amar
Published: July 2019

Fetal micrognathia involves abnormal or arrested development of the fetal mandible. Till recently, the prenatal diagnosis was subjective, based on the evaluation of the fetal profile and assessment of the relationship between the maxilla and the mandible. Recently objective sonographic methods have been utilized for diagnosing micrognathia such as the inferior facial angle, the jaw index, the frontal nasomental angle, the mandible width/maxilla width ratio and the mandibular length. Another useful sonographic sign, the mandibular gap in the retronasal triangle view, increases the accuracy of the diagnosis early in the first trimester. 3D sonographic views can add to the diagnosis and prenatal MRI is a useful adjunct to ultrasound in cases of limited acoustic window, maternal obesity, oligohydramnios and anterior spine position. The identification of micrognathia should prompt karyotyping and sonographic investigation for other abnormalities. The outcome of fetuses with this seemingly isolated finding is more guarded than one would intuitively believe, and the parents should be counseled accordingly. Postnatal complications including mild to severe upper airway obstruction leading to respiratory distress, feeding difficulties and mild to severe long-term developmental delay are common. One should be careful in pronouncing a fetus having ‘micrognathia’, especially on subjective evaluation, as this term implies that the fetus is abnormal with presence of significant pathology. There is no ‘gold standard’ for a definitive diagnosis of micrognathia on post-natal evaluation. Using a combination of objective sonographic markers as well as follow-up ultrasound assessments can significantly reduce the risk of a false diagnosis. Follow-up scans should be arranged, and neonatal service should be alerted in cases of ongoing pregnancies.
Prenatal Diagnosis of Atretic Occipital Cephalocele: A Case Report
Authors: Kunt İşgüder Çiğdem , Koşar Can Özlem , Kanat Pektaş Mine , GÖkçe Erkan
Published: July 2019

Atretic cephaloceles refer to the congenital herniation of meningeal and vestigial tissues such as arachnoid, glial or neural rests. These small, skin covered subscalp lesions usually appear within a few centimetres of the lambda and nearly half of them have a parietal situation, the remaining half have occipital, parieto-occipital, frontal, asterion, and sincipital locations. Atretic cephaloceles can be isolated or associated with congenital syndromes, agenesis of corpus callosum, grey matter heterotopias, ventriculomegaly, mental retardation, developmental delay, epilepsy, spasticity, speech difficulty, strabismus, optic nerve atrophy, microphthalmia, enophthalmos, cleft palate, hypertelorism, congenital cardiac and vascular defects, renal agenesis, hearing problems, congenital lobar emphysema, and muscular anomalies. This case report describes a newborn which has been diagnosed with atretic occipital cephalocele prenatally and also bilateral cochlear hypoplasia postnatally.
Attributable costs and length of stay of hospital-acquired Clostridioides difficile: A population-based matched cohort study in Alberta, Canada
Authors: Leal Jenine R. , Conly John , Weaver Robert , Wick James , Henderson Elizabeth A. , Manns Braden , Ronksley Paul
Published: July 2019

Objective:

To determine the attributable cost and length of stay of hospital-acquired Clostridioides difficile infection (HA-CDI) from the healthcare payer perspective using linked clinical, administrative, and microcosting data.

Design:

A retrospective, population-based, propensity-score–matched cohort study.

Setting:

Acute-care facilities in Alberta, Canada.

Patients:

Admitted adult (≥18 years) patients with incident HA-CDI and without CDI between April 1, 2012, and March 31, 2016.

Methods:

Incident cases of HA-CDI were identified using a clinical surveillance definition. Cases were matched to noncases of CDI (those without a positive C. difficile test or without clinical CDI) on propensity score and exposure time. The outcomes were attributable costs and length of stay of the hospitalization where the CDI was identified. Costs were expressed in 2018 Canadian dollars.

Results:

Of the 2,916 HA-CDI cases at facilities with microcosting data available, 98.4% were matched to 13,024 noncases of CDI. The total adjusted cost among HA-CDI cases was 27% greater than noncases of CDI (ratio, 1.27; 95% confidence interval [CI], 1.21–1.33). The mean attributable cost was $18,386 (CAD 2018; USD $14,190; 95% CI, $14,312–$22,460; USD $11,046-$17,334). The adjusted length of stay among HA-CDI cases was 13% greater than for noncases of CDI (ratio, 1.13; 95% CI, 1.07–1.19), which corresponds to an extra 5.6 days (95% CI, 3.10–8.06) in length of hospital stay per HA-CDI case.

Conclusions:

In this population-based, propensity score matched analysis using microcosting data, HA-CDI was associated with substantial attributable cost.
SEPARATING THE FAN THEOREM AND ITS WEAKENINGS II
Authors: LUBARSKY ROBERT S.
Published: July 2019

Varieties of the Fan Theorem have recently been developed in reverse constructive mathematics, corresponding to different continuity principles. They form a natural implicational hierarchy. Earlier work showed all of these implications to be strict. Here we reprove one of the strictness results, using very different arguments. The technique used is a mixture of realizability, forcing in the guise of Heyting-valued models, and Kripke models.
A Timely Intervention: Tracking the Changing Meanings of Political Concepts with Word Vectors
Authors: Rodman Emma
Published: July 2019

Word vectorization is an emerging text-as-data method that shows great promise for automating the analysis of semantics—here, the cultural meanings of words—in large volumes of text. Yet successes with this method have largely been confined to massive corpora where the meanings of words are presumed to be fixed. In political science applications, however, many corpora are comparatively small and many interesting questions hinge on the recognition that meaning changes over time. Together, these two facts raise vexing methodological challenges. Can word vectors trace the changing cultural meanings of words in typical small corpora use cases? I test four time-sensitive implementations of word vectors (word2vec) against a gold standard developed from a modest data set of 161 years of newspaper coverage. I find that one implementation method clearly outperforms the others in matching human assessments of how public dialogues around equality in America have changed over time. In addition, I suggest best practices for usingword2vecto study small corpora for time series questions, including bootstrap resampling of documents and pretraining of vectors. I close by showing thatword2vecallows granular analysis of the changing meaning of words, an advance over other common text-as-data methods for semantic research questions.
The causal interpretation of estimated associations in regression models
Authors: Keele Luke , Stevenson Randolph T. , Elwert Felix
Published: July 2019

A common causal identification strategy in political science is selection on observables. This strategy assumes one observes a set of covariates that is, after statistical adjustment, sufficient to make treatment status as-if random. Under adjustment methods such as matching or inverse probability weighting, coefficients for control variables are treated as nuisance parameters and are not directly estimated. This is in direct contrast to regression approaches where estimated parameters are obtained for all covariates. Analysts often find it tempting to give a causal interpretation to all the parameters in such regression models—indeed, such interpretations are often central to the proposed research design. In this paper, we ask when we can justify interpreting two or more coefficients in a regression model as causal parameters. We demonstrate that analysts must appeal to causal identification assumptions to give estimates causal interpretations. Under selection on observables, this task is complicated by the fact that more than one causal effect might be identified. We show how causal graphs provide a framework for clearly delineating which effects are presumed to be identified and thus merit a causal interpretation, and which are not. We conclude with a set of recommendations for how researchers should interpret estimates from regression models when causal inference is the goal.
Effectiveness of school–home intervention for adolescent obesity prevention: parallel school randomised study
Authors: Sgambato Michele R. , Cunha Diana B. , Souza Bárbara S. N. , Henriques Viviana T. , Rodrigues Renata R. M. , Rêgo Ana L. V. , Pereira Rosangela A. , Yokoo Edna M. , Sichieri Rosely
Published: July 2019

Many school-based interventions for obesity prevention have been proposed with positive changes in behaviour, but with unsatisfactory results on weight change. The objective was to verify the effectiveness of a combined school- and home-based obesity prevention programme on excessive weight gain in adolescents. Teachers delivered the school-based primary prevention programme to fifth- and sixth-graders (nine schools, forty-eight control classes, forty-nine intervention classes), which included encouraging healthy eating habits and physical activity. A subgroup of overweight or obese adolescents also received a home-based secondary prevention programme delivered by community health professionals. Schools were randomised to intervention or control group. Intent-to-treat analysis used mixed models for repeated continuous measures and considered the cluster effect. The main outcomes were changes in BMI and percentage body fat (%body fat) after one school-year of intervention and follow-up. Against our hypothesis, BMI increased more in the intervention group than in the control group (Δ = 0·3 kg/m2; P = 0·05) with a greater decrease in %body fat among boys (Δ = –0·6 %; P = 0·03) in the control group. The intervention group increased physical activity by 12·5 min per week compared with the control group. Female adolescents in the intervention group ate healthier items more frequently than in the control group. The subgroup that received both the school and home interventions had an increase in %body fat than in the control group (Δ = 0·89 %; P = 0·01). In the present study, a behavioural change led to a small increase in physical activity and healthy eating habits but also to an overall increase in food intake.
Linguistic interdependence of receptive vocabulary skills in emergent bilingual preschool children: Exploring a factor-dependent approach
Authors: Sierens Sven , Slembrouck Stef , Van Gorp Koen , Agirdag Orhan , Van Avermaet Piet
Published: July 2019

This study investigates the extent to which internal and contextual factors moderate the linguistic interdependence between receptive vocabulary skills in emergent bilingual children. Such factors are frequently related to first (L1) and second language (L2) skills, but few studies have examined their concurrent influence on the cross-language relationship, or have linked the results to the two main explanatory models for interdependence: common underlying proficiency or individual differences. Using a cross-sectional correlational design, concept comprehension was bilingually assessed in 154 children of Turkish background (aged 4 to 6), attending Flemish preschool. Regression analyses revealed that Turkish L1 vocabulary size significantly predicted Dutch L2 vocabulary size, which is in line with interdependence theories. Age, preschool grade, and L2 use at home positively predicted L2 vocabulary. Newly arrived immigrant status and maternal education (partly) predicted L2 vocabulary negatively, the latter especially in 3rd preschool grade. Concerning moderation, indications were found for weakening interdependence for high L2 use at home (3rd preschool grade) and newly arrived immigrant status. Overall, our findings implicate that interdependence in emergent bilinguals’ vocabulary depends on the examined factors to a limited degree only. Finally, our data point to the individual differences model, rather than the common underlying proficiency model of linguistic interdependence.
Computation of the safe working zones of Planar and Spatial Parallel Manipulators
Authors: Karnam Murali K. , Baskar Aravind , Srivatsan Rangaprasad A. , Bandyopadhyay Sandipan
Published: July 2019

This paper presents the computation of the safe working zone (SWZ) of a parallel manipulator having three degrees of freedom. The SWZ is defined as a continuous subset of the workspace, wherein the manipulator does not suffer any singularity, and is also free from the issues of link interference and physical limits on its joints. The proposed theory is illustrated via application to two parallel manipulators: a planar 3-R̲RR manipulator and a spatial manipulator, namely, MaPaMan-I. It is also shown how the analyses can be applied to any parallel manipulator having three degrees of freedom, planar or spatial.
On starting to teach using CI
Authors: Ramahlo Michelle
Published: July 2019

According to Second Language Acquisition (SLA) theory, developed by Stephen Krashen, the way humans acquire languages is through receiving input, usually aural, that is understandable; this is termed ‘Comprehensible Input’ (CI). Think, for example, of a parent talking to their child: when they ask the child, ‘Do you want milk?’, the milk is visible, tangible. The child understands that they are being offered milk. Parents don't just say this once, they offer it hundreds, even thousands of times. According to this hypothesis, the input (the parent talking) is comprehensible (the child understands it); the brain is trained to automatically make meaning.
TPRS, PQA & circling
Authors: Bracey John
Published: July 2019

Latin is no longer the exclusive dominion of the elite. The Latin language is now accessible to all types of students as a result of the shift towards the use of Comprehensible Input in the Latin classroom. Part of making Latin accessible to the many involves divorcing oneself from limiting beliefs about what constitutes content in the Latin classroom. Enter Blaine Ray and Teaching Proficiency through Reading and Storytelling (TPRS).
Free Voluntary Reading and Comprehensible Input
Authors: Patrick Miriam
Published: July 2019

Three and a half years into my journey of using Comprehensible Input and leaving the textbook behind, I started doing research on Free Voluntary Reading. As a child, I had greatly enjoyed reading and it was something my students had a hard time grasping. Similarly, my own brother nearly stopped reading all together when his school adopted the Accelerated Reader program, which assigns points for reading and testing on books. His love for reading was later reignited when, as a family, we started reading the Harry Potter series. I want my own students to have a similar experience and enjoy reading.
Graffiti on the walls: an action research plan on how making authentic opportunities for student composition helps Latin 1 comprehension
Authors: Holke Jacob
Published: July 2019

With the changes made in the new US Standards for Classical Language Learning, pedagogy needs to develop to better meet the updated standards for student learning. One of the major changes is that reading Latin is no longer the sole pursuit of a high school Latin class (Standards, 2017; Natoli, 2018). The new standards recognise that students learn in diverse ways and that students need to learn about and interact with the cultures they are studying.
Caledonia resurgens: reflections on the campaign to revive Classics in Scotland
Authors: Imrie Alex
Published: July 2019

In late 2017, the Classical Association of Scotland, in association with Classics for All, hired a co-ordinator to commence a programme of outreach and public engagement activities across the country. In this article, the national outreach co-ordinator reflects on the progress made to date, the difficulties faced, and hopes and plans for the future.
Variation in Prevalence of Rare Heritable Traits — A Simulation Study — Illustrated by Neurofibromatosis Type 1
Authors: Stark Alan E.
Published: July 2019

The epidemiology of heritable traits whose prevalence is determined by a balance between mutation and selection is often explored through deterministic models. Here, the properties are explored by simulation of a model population followed through a sequence of closely spaced time points. Mutation and birth and death occur randomly. The condition neurofibromatosis type 1 (NF1) is used as a point of reference. Critical parameters, such as mutation rates and selection forces, are not known precisely for NF1 so speculative values based on published data from Finland and other studies are proposed.
Differential response of horseweed (Conyza canadensis) to halauxifen-methyl, 2,4-D, and dicamba
Authors: McCauley Cara L. , Young Bryan G.
Published: July 2019

Halauxifen-methyl is an auxin herbicide for broadleaf weed control in preplant applications to corn and soybean. Our objective for this research was to characterize the phytotoxicity of halauxifen-methyl on horseweed, relative to 2,4-D and dicamba, in terms of weed height, the response to an auxin synergist, and root activity. The 50% reduction in plant growth (GR50) value for halauxifen-methyl on rosette-sized plants was 0.05 g ae ha−1, 100 times less than the labeled use rate of 5 g ae ha−1, compared with 36 and 31 g ha−1 for 2,4-D and dicamba, respectively. In a whole-plant bioassay, 240 g ae ha−1 of 2,4-D was calculated as the GR50 value on horseweed 20-cm tall, whereas applications of only 53 and 0.40 g ae ha−1 were necessary for dicamba and halauxifen-methyl, respectively, to achieve the same response. As weed size decreased, there was a concomitant reduction in the estimated herbicide dose for the GR50 with similar differences observed between halauxifen-methyl and the other two auxin herbicides. The addition of diflufenzopyr, an auxin synergist, to 2,4-D and dicamba resulted in a synergistic response on horseweed. However, the addition of diflufenzopyr to halauxifen-methyl resulted in an additive or antagonistic effect, depending on rate of diflufenzopyr, demonstrating a distinctive physiological pathway for halauxifen-methyl compared with 2,4-D and dicamba. In the agar-based bioassays, GR50 values for horseweed root length for 2,4-D and dicamba were 0.16 and 0.19 µM, respectively, whereas only 0.004 µM halauxifen-methyl was required for a comparable root response. These results indicate that horseweed exhibits a high level of sensitivity to halauxifen-methyl and suggest the activity of halauxifen-methyl is different from that of 2,4-D and dicamba. These differences in herbicide activity may reflect differential absorption, translocation, metabolism, or targeting of auxin receptors found in horseweed.