bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparing Numerical Accuracy of Icosahedral A-Grid and C-Grid Schemes in Solving the Shallow-Water Model
Authors: Yu Yonggang G. , Wang Ning , Middlecoff Jacques , Peixoto Pedro S. , Govett Mark W.
Published: August 2020

A single software framework is introduced to evaluate numerical accuracy of the A-grid (NICAM) versus C-grid (MPAS) shallow-water model solvers on icosahedral grids. The C-grid staggering scheme excels in numerical noise control and total energy conservation, which results in exceptional stability for long time integration. Its weakness lies in the lack of model error reduction with increasing resolution in specific test cases (especially the root-mean-square error). The A-grid method conserves well potential enstrophy and shows a linear reduction of error with increasing resolution. The gridpoint noise manifests itself clearly on A-grid, but much less on C-grid. We show that the Coriolis force term on C-grid has a larger error than on A-grid. To treat the Coriolis term and kinetic energy gradient on an equal footing on C-grid, we propose combining these two quantities into a single tendency term and computing its value by a linear combination operation. This modification alone reduces numerical errors but still fails to converge the maximum error with resolution. The method of Peixoto can solve the maximum-error nonconvergence problem on C-grid but degrades the numerical stability. For the steady-state thin-layer test (0.01 m in depth), the A-grid method is less susceptible than C-grid methods, which are presumably disrupted by the Hollingsworth instability. The effect of horizontal diffusion on model accuracy and energy conservation is shown in detail. Programming experience shows that software implementation and optimization can strongly influence computational performance for models, although memory requirement and computational load of the two schemes are comparable.
Eastward-Propagating Disturbances in the Tropical Pacific
Authors: Huaman Lidia , Schumacher Courtney , Kiladis George N.
Published: August 2020

Within the tropical Pacific intertropical convergence zone (ITCZ), organized cloud systems that evolve over synoptic time scales frequently propagate eastward and contribute significantly to the clouds and precipitation in that region. This study analyzes eastward-propagating disturbances (EPDs) in the tropical Pacific during boreal winter (DJF) and spring (MAM) and their connection to Northern Hemisphere (NH) extratropical Rossby wave activity using cloud and precipitation fields from satellite and dynamical fields from reanalysis. During DJF, EPDs are located north of the ITCZ (around 15°N), propagate eastward at 10 m s−1 within the central Pacific, and exhibit high cloudiness associated with upper-level divergence on the east side of NH Rossby waves propagating into the tropics. During MAM, EPDs initiate in the west Pacific and propagate along the ITCZ axis (around 7°N) into the east Pacific at 15 m s−1 where NH Rossby waves induce upper-level divergence, enhancing their convective activity. The MAM EPDs are decidedly associated with Kelvin wave characteristics, while the DJF EPDs are not. The shallow meridional circulation (SMC) in the east Pacific is also studied in the context of EPDs. During DJF, EPDs do not impact the SMC, but the deep meridional circulation in the northern part of the ITCZ strengthens. During MAM, the shallow convection ahead of the EPDs enhances the SMC in the southern part of the ITCZ. These results distinguish between two types of EPDs during DJF and MAM that have different physical characteristics, forcing mechanisms, and regional impacts.
Rapid-Scan and Polarimetric Radar Observations of the Dissipation of a Violent Tornado on 9 May 2016 near Sulphur, Oklahoma
Authors: McKeown Katherine E. , French Michael M. , Tuftedal Kristofer S. , Kingfield Darrel M. , Bluestein Howard B. , Reif Dylan W. , Wienhoff Zachary B.
Published: August 2020

Rapid-scan polarimetric data analysis of the dissipation of a likely violent supercell tornado that struck near Sulphur, Oklahoma, on 9 May 2016 is presented. The Rapid X-band Polarimetric Radar was used to obtain data of the tornado at the end of its mature phase and during its entire dissipation phase. The analysis is presented in two parts: dissipation characteristics of the tornadic vortex signature (TVS) associated with the tornado and storm-scale polarimetric features that may be related to processes contributing to tornado dissipation. The TVS exhibited near-surface radial velocities exceeding 100 m s−1 multiple times at the end of its mature phase, and then underwent a two-phased dissipation. Initially, decreases in near-surface intensity occurred rapidly over a ~5-min period followed by a slower decline in intensity that lasted an additional ~12 min. The dissipation of the TVS in time and height in the lowest 2 km above radar level and oscillatory storm-relative motion of the TVS also are discussed. Using polarimetric data, a well-defined low reflectivity ribbon is investigated for its vertical development, evolution, and relationship to the large tornadic debris signature (TDS) collocated with the TVS. The progression of the TDS during dissipation also is discussed with a focus on the presence of several bands of reduced copolar correlation coefficient that extend away from the main TDS and the eventual erosion of the TDS as the tornado dissipated. Finally, TVS and polarimetric data are combined to argue for the importance of a possible internal rear-flank downdraft momentum surge in contributing to the initial rapid dissipation of the tornado.
Convection Initiation and Growth at the Coast of South China. Part II: Effects of the Terrain, Coastline, and Cold Pools
Authors: Du Yu , Chen Guixing , Han Bin , Bai Lanqiang , Li Minghua
Published: August 2020

Through conducting dynamic and thermodynamic diagnoses as well as a series of numerical sensitivity simulations, we investigated the effects of the terrain, coastline, and cold pools on convection initiation (CI) and its subsequent upscale convective growth (UCG) during a case of heavy rainfall along the coast of South China. CI occurred at the vertex of the coastal concave mountain geometry as a combined result of coastal convergence, orographic lifting, and mesoscale ascent driven by the terminus of a marine boundary layer jet (MBLJ). In numerical simulations with the coastline or terrain of South China removed, the coastal CI does not occur or becomes weaker as the MBLJ extends farther north, suggesting that the coastline and terrain play a role in CI. In addition, local small-scale terrain can modulate the detailed location and timing of CI and UCG. When the coastal concave terrain and coastline near the CI are artificially removed or filled by additional mountains, the orographic lifting and the local convergence along the coast correspondingly change, which strongly affects the CI and UCG. From a thermodynamic perspective, the coastal concave terrain plays the role of a local moisture “catcher,” which promotes low-level moistening by blocking water vapor coming from an upstream moist tongue over the ocean. Furthermore, new convection is continuously generated by the lifting of low-level moist southerlies at the leading edges of cold pools that tend to move southeastward because of the blocking coastal mountains. Sensitivity experiments suggest that the MCS becomes weaker and moves more slowly when cold pools are weakened through a reduction of rain-evaporation cooling.
Two Ensemble Approaches for Forecasting Sulfur Dioxide Concentrations from Kīlauea Volcano
Authors: Holland Lacey , Businger Steven , Elias Tamar , Cherubini Tiziana
Published: August 2020

Kīlauea volcano, located on the island of Hawaii, is one of the most active volcanoes in the world. It was in a state of nearly continuous eruption from 1983 to 2018 with copious emissions of sulfur dioxide (SO2) that affected public health, agriculture, and infrastructure over large portions of the island. Since 2010, the University of Hawaiʻi at Mānoa provides publicly available vog forecasts that began in 2010 to aid in the mitigation of volcanic smog (or “vog”) as a hazard. In September 2017, the forecast system began to produce operational ensemble forecasts. The months that preceded Kīlauea’s historic lower east rift zone eruption of 2018 provide an opportunity to evaluate the newly implemented air quality ensemble prediction system and compare it another approach to the generation of ensemble members. One of the two approaches generates perturbations in the wind field while the other perturbs the sulfur dioxide (SO2) emission rate from the volcano. This comparison has implications for the limits of forecast predictability under the particularly dynamic conditions at Kīlauea volcano. We show that for ensemble forecasts of SO2 generated under these conditions, the uncertainty associated with the SO2 emission rate approaches that of the uncertainty in the wind field. However, the inclusion of a fluctuating SO2 emission rate has the potential to improve the prediction of the changes in air quality downwind of the volcano with suitable postprocessing.
A Climatological Analysis of Ambient Deep-Tropospheric Vertical Wind Shear Impacts upon Tornadoes in Tropical Cyclones
Authors: Schenkel Benjamin A. , Edwards Roger , Coniglio Michael
Published: August 2020

The cyclone-relative location and variability in the number of tornadoes among tropical cyclones (TCs) are not completely understood. A key understudied factor that may improve our understanding is ambient (i.e., synoptic-scale) deep-tropospheric (i.e., 850–200-hPa) vertical wind shear (VWS), which impacts both the symmetry and strength of deep convection in TCs. This study conducts a climatological analysis of VWS impacts upon tornadoes in TCs from 1995 to 2018, using observed TC and tornado data together with radiosondes. TC tornadoes were classified by objectively defined VWS categories, derived from reanalyses, to quantify the sensitivity of tornado frequency, location, and their environments to VWS. The analysis shows that stronger VWS is associated with enhanced rates of tornado production—especially more damaging ones. Tornadoes also become localized to the downshear half of the TC as VWS strengthens, with tornado location in strongly sheared TCs transitioning from the downshear-left quadrant in the TC inner core to the downshear-right quadrant in the TC outer region. Analysis of radiosondes shows that the downshear-right quadrant in strongly sheared TCs is most frequently associated with sufficiently strong near-surface speed shear and veering aloft, and lower-tropospheric thermodynamic instability for tornadoes. These supportive kinematic environments may be due to the constructive superposition of the ambient and TC winds, and the VWS-induced downshear enhancement of the TC circulation among other factors. Together, this work provides a basis for improving forecasts of TC tornado frequency and location.
A Bayesian Representation of the Storm Approach Probability Based on Operational Track Forecast Errors
Authors: Kang Namyoung
Published: August 2020

This study provides a statistical review on the forecast errors of tropical storm tracks and suggests a Bayesian procedure for updating the uncertainty about the error. The forecast track errors are assumed to form an axisymmetric bivariate normal distribution on a two-dimensional surface. The parameters are a mean vector and a covariance matrix, which imply the accuracy and precision of the operational forecast. A Bayesian method improves quantifying the varying parameters in the bivariate normal distribution. A normal-inverse-Wishart distribution is employed to determine the posterior distribution (i.e., the weights on the parameters). Based on the posterior distribution, the predictive probability density of track forecast errors is obtained as the marginal distribution. Here, “storm approach” is defined for any location within a specified radius of a tropical storm. Consequently, the storm approach probability for each location is derived through partial integration of the marginal distribution within the forecast storm radius. The storm approach probability is considered a realistic and effective representation of storm warning for communicating the threat to local residents since the location-specific interpretation is available on a par with the official track forecast.
The Overall Poor Specificity of MRCP in the Preoperative Evaluation of the Jaundiced Patient Will Increase the Incidence of Nontherapeutic ERCP
Authors: O’Neill Andrew M. , Anderson Keith , Baker Lorinda K. , Schurr Michael J.
Published: August 2020

Laparoscopic cholecystectomy remains one of the most common surgical operations. Common bile duct stones (CBDS) are estimated to be present in 10%-20% of individuals with symptomatic gallstones. Preoperative magnetic resonance cholangiopancreatography (MRCP) and intraoperative cholangiography (IOC) remain the most common methods of evaluation, with subsequent endoscopic retrograde cholangiopancreatography (ERCP) for stone extraction if positive for CBDS. We examined our experience with preoperative MRCP versus IOC for the management of the jaundiced patient with cholelithiasis. This is a retrospective single-institution study that examined all laparoscopic cholecystectomies performed over a 15-month period between 2017 and 2018. Outpatient elective cases were excluded from the analysis. Charts were reviewed for demographics, operative details, and whether an MRCP, IOC, or ERCP was performed. Data were evaluated using a 2-sample t-test. A total of 460 patients underwent laparoscopic cholecystectomy over a 15-month period. Of those, 147 underwent either an MRCP or an IOC for clinical suspicion for CBDS. ERCP after MRCP was nontherapeutic in 11/32 (34%) compared with 2/12 (17%) of patients following IOC. The sensitivity and specificity of MRCP were 91% and 80%, respectively, with a positive predictive value of 66% and a negative predictive value of 96%. The sensitivity and specificity of IOC were 83% and 97%, respectively, with a positive predictive value of 83% and a negative predictive value of 97%. MRCP and IOC have unique advantages and disadvantages. MRCP has greater sensitivity, but poor specificity, resulting in unnecessary ERCPs with associated morbidity and increased costs to the patient.
Robotic Versus Laparoscopic Approach to Hiatal Hernia Repair: Results After 7 Years of Robotic Experience
Authors: O’Connor Sean C. , Mallard Matthew , Desai Shivani S. , Couto Francisco , Gottlieb Matthew , Ewing Alex , Cobb William S. , Carbonell Alfredo M. , Warren Jeremy A.
Published: August 2020

Introduction

Robotic hiatal hernia repair offers potential advantages over traditional laparoscopy, most notably enhanced visualization, improved ergonomics, and articulating instruments. The clinical outcomes, however, have not been adequately evaluated. We report outcomes of laparoscopic and robotic hiatal hernia repairs.

Methods

A retrospective observational cohort study was performed of all hiatal hernia repairs performed from 2006 through 2019. Operative, demographic, and outcomes data were compared between laparoscopic and robotic groups. Discrete variables were analyzed with Chi-square of Fisher’s exact test. Continuous variables were analyzed with Student’s t test (mean) or Wilcoxon rank sum (medians). All analyses were performed using R statistical software.

Results

Laparoscopic repair was performed in 278 patients and robotic repair in 114. More recurrent hernias were repaired robotically (24.5% vs 12.9%, P = .08). Operative times were no different between groups (175 vs 179 minutes; P = .681). Robotic repair resulted in significantly shorter length of stay (LOS; 2.3 vs 3.3 days; P = .003). Rate of readmission was no different, and there were no differences in acute complications. For patients with at least 1 year of follow-up, recurrence rates were lower after robotic repair (13.3% vs 32.8%; P = .008); however, mean follow-up is significantly longer after laparoscopic repair (23.7 ± 28.4 vs 15.1 ± 14.9 months; P < .001).

Discussion

Robotic hiatal hernia repair offers technical advantages over laparoscopic repair with similar clinical outcomes.
How Does the Stock Market Value Female Directors? International Evidence
Authors: Loy Thomas R. , Rupertus Hendrik
Published: August 2020

We analyze investors’ perception and long-term effects of board gender diversity on firms’ stock market performance in an international setting. Our results, controlling for the endogenous nature of board compositions, indicate that female board representation neither improves nor reduces firms’ long-term stock performance. Hence, we argue that it is imperative to go beyond the conventional thinking in terms of the business case for gender diversity and broaden the perspective also to incorporate societal and ethical aspects in the strive to board gender equality. Even more so, as our results show that it does not entail reduced shareholder value, which the literature on mandatory gender quotas commonly seems to suggest.
World Christianity as ‘Human Universal Making’ Activity: The Contribution of African Christian Potential
Authors: Kaunda Chammah J.
Published: August 2020

The study engages Alain Badiou’s philosophical concept of ‘immanent exception’ to establish the special potential embedded in African Christianity for engendering human universal (Umuntu). It argues that African Christian experiences inform their interpretations of Jesus Christ as the answer to all human existential concerns. This approach forces them to ‘exceed’ in the locations and spaces of their imaginations of suffering by embracing ambivalent localizations (through a constant oscillation between local and un-local) in search to transcend, not escape, in thought and practice their negative realities. Thus, they transcend unitary Christian boundaries and integrates critical elements of African spiritual systems to build human universal within the paradigmatic universal humanity of Jesus. The study underlines that grasping African Christianity through immanent exception could contribute to empowering not only African Christians, but also world Christians to seek new ways of becoming human universal for global struggle against death dealing forces such as COVID-19. The study concludes by calling for the need to engage how World Christianity in its particularities is shaping life today and how local churches are participating in constructing what it means to be part of God’s mission to build a human universal in active search for global justice.
Biological Plausibility of Arm Postures Influences the Controllability of Robotic Arm Teleoperation
Authors: Mick Sébastien , Badets Arnaud , Oudeyer Pierre-Yves , Cattaert Daniel , De Rugy Aymar
Published: August 2020

Objective

We investigated how participants controlling a humanoid robotic arm’s 3D endpoint position by moving their own hand are influenced by the robot’s postures. We hypothesized that control would be facilitated (impeded) by biologically plausible (implausible) postures of the robot.

Background

Kinematic redundancy, whereby different arm postures achieve the same goal, is such that a robotic arm or prosthesis could theoretically be controlled with less signals than constitutive joints. However, congruency between a robot’s motion and our own is known to interfere with movement production. Hence, we expect the human-likeness of a robotic arm’s postures during endpoint teleoperation to influence controllability.

Method

Twenty-two able-bodied participants performed a target-reaching task with a robotic arm whose endpoint’s 3D position was controlled by moving their own hand. They completed a two-condition experiment corresponding to the robot displaying either biologically plausible or implausible postures.

Results

Upon initial practice in the experiment’s first part, endpoint trajectories were faster and shorter when the robot displayed human-like postures. However, these effects did not persist in the second part, where performance with implausible postures appeared to have benefited from initial practice with plausible ones.

Conclusion

Humanoid robotic arm endpoint control is impaired by biologically implausible joint coordinations during initial familiarization but not afterwards, suggesting that the human-likeness of a robot’s postures is more critical for control in this initial period.

Application

These findings provide insight for the design of robotic arm teleoperation and prosthesis control schemes, in order to favor better familiarization and control from their users.
Investigation of nano-hybridization effects on low velocity impact behaviors of basalt fiber reinforced composites
Authors: Demirci İbrahim , Avcı Ahmet , Demirci Mehmet Turan
Published: August 2020

In general the nanoparticles increase the mechanical and impact behaviors of fiber reinforced polymer based composites. However, the effects of the hybridization of nanoparticles and their reasons over the nano scale fracture mechanisms have not been adequately studied for fiber reinforced composites. In this study, the low velocity impact responses and the mechanical behaviors were investigated for 4%wt. SiO2 nanoparticles filled BFR/Epoxy nanocomposites, 0.5%wt. MWCNTs filled BFR/Epoxy nanocomposites, 4%wt. SiO2 nanoparticles and 0.5%wt. MWCNTs nano-hybrid filled BFR/Epoxy nanocomposites and unfilled BFR/Epoxy composites. The tensile and low velocity impact tests at 10 J and 20 J of energy levels were applied to nanoparticles, nano-hybrid and unfilled BFR/Epoxy composites in order to define the effects of nanoparticles and nano-hybrid particles on the impact and mechanical features according to in accordance with ASTM D3039/D3039M-14 and ASTM D7136/7136M standards. It was observed that SiO2 nanoparticles addition to BFR/Epoxy for both 10 J and 20 J showed the highest tensile strength, maximum force, rebound energy and the lowest displacements and absorbed energy. SiO2+MWCNTs nano-hybrid addition to BFR/Epoxy improved higher low velocity impact responses and tensile strength than MWCNTs addition. The specimens of unfilled BFR/Epoxy composites showed the lowest tensile strength and maximum force and the highest maximum force, displacements and absorbed energy. Microscope and SEM analyses demonstrated that minimum failures like fiber breakages, delamination and debonding were observed by filling SiO2 nanoparticles provided the nano scale fracture mechanisms. In addition MWCNTs hybridization with SiO2 nanoparticles minimizes negative effects of MWCNTs micro size length and improved the impact and mechanical behaviors.
Seawater effects on interlaminar fracture toughness of glass fiber/epoxy laminates modified with multiwall carbon nanotubes
Authors: Rodríguez-González Julio A , Rubio-González Carlos
Published: August 2020

In this work, the effect of seawater ageing on mode I and mode II interlaminar fracture toughness ([Formula: see text] and [Formula: see text]) of prepreg-based woven glass fiber/epoxy laminates with and without multiwall carbon nanotubes (MWCNTs) has been investigated. The first part of the investigation reports the moisture absorption behavior of multiscale composite laminates exposed to seawater ageing for ∼3912 h at 70 °C. Then, the results of mode I and mode II fracture tests are presented and a comparison of [Formula: see text] and [Formula: see text] for each type of material group and condition is made. Experimental results showed the significant effect of seawater ageing on [Formula: see text] of multiscale composite laminates due to matrix plasticization and fiber bridging. The improvement in [Formula: see text] of the wet glass fiber/epoxy laminate was about 50% higher than that of the neat laminate (without MWCNTs) under dry condition. It was also found that the presence of MWCNTs into composite laminates promotes a moderate increase (8%) in their [Formula: see text] as a result of the additional toughening mechanisms induced by CNTs during the delamination process. Scanning electron microscopy analysis conducted on fracture surface of specimens reveals the transition from brittle (smooth surface) to ductile (rough surface) in the morphology of composite laminates due to the influence of seawater ageing on the polymeric matrix and fiber/matrix interface.
Fiber cement boards modified with styrene-acrylic copolymer: An approach to address dimensional stability and cellulose fiber preservation
Authors: Cruz EO , Radler MJ , Perello M , Savastano Jr H
Published: August 2020

The performance of polymers such as acrylics, styrene-acrylics, styrene-butadiene, ethylene vinyl acetate, type added in cementitious composites are well reported in the literature to boost properties in the fresh mortar stage as workability, anti-bleeding, and hard stage as deformation, adhesion strength, crack bridging, cohesion, durability and reduced water uptake. Polymer treatment was performed in fiber cement boards by adding 5% w/w (dry basis) of styrene-acrylic copolymer aiming to investigate the impact on the mechanical and physical properties at initial curing period (28 days) and after the 200 soak and drying ageing cycles. Dimensional stability at 28 days and the cellulose fiber/cement interface transition zone were assessed by scanning electron microscopy combined with dispersive energy X-ray spectroscopy (EDS). These experiments confirmed that the water absorption value in polymer modified cement boards was reduced by 50% after the ageing cycles when compared to the unmodified boards. Additionally, improvements on board’s rigidity with reduction of modulus of elasticity (MOE) values up to 40% and 15% reduction of board shrinkage was noticed, enhancing boards dimensional stability and preventing fibers from the mineralization process by keeping the cellulose fiber adhered on the cementitious matrix, providing a dense and cohesive fiber-cement interface transition zone after the ageing cycles. This achievement can open important fields of application for the reinforcement of flat panels.
Trends in Location of Death in Patients With Aortic Aneurysm and Dissection
Authors: DeCicco Danielle , Dimachkie Ziad O. , Khan Muhammad Z. , Khan Muhammad S. , Khan Muhammad U. , Khan Safi U.
Published: August 2020

Aortic dissections and aneurysms (ADA) are associated with significant morbidity and mortality, and location of death for these patients is important in determining impact on end of life care. We analyzed the Centers for Disease Control and Prevention Wide-ranging Online Data for Epidemiologic Research database. Black and Hispanic backgrounds had decreased odds of dying at home from ADA. Married or educated individuals tended to die at home at a higher rate than unmarried individuals. Overall, we have shown place of death in individuals with ADA is different among individuals of different demographics.
Renin-angiotensin system antagonists are associated with lower mortality in hypertensive patients with COVID-19
Authors: Megaly Michael , Glogoza Mattew
Published: August 2020

The use of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin-receptor blockers (ARBs) in patients with Coronavirus 2019 (COVID-19) has been controversial. We performed a meta-analysis of all published studies that reported the outcomes of ACEIs/ARBs in patients with COVID-19. We included four observational studies (3,267 patients). The use of ACEIs/ARBs was associated with a similar risk of all-cause death (OR: 0.75, 95% CI [0.36, 1.57], p = 0.45). Sensitivity analysis including only hypertensive patients demonstrated a lower risk of death with ACEIs/ARBs use (OR: 0.57, 95% CI [0.32-0.98], p = 0.04). In conclusion, hypertensive patients with COVID-19 treated with ACEIs/ARBS have a lower mortality but further research is needed.
Religious discrimination in young Muslim assimilation in Spain: Contributions to Portes and Rumbaut’s segmented assimilation theory
Authors: Collet-Sabé Jordi
Published: August 2020

This article aims to consider the role of religion in the integration process of children born to immigrants in host societies (second generation) in Spain using the theory of segmented assimilation of Portes and Rumbaut and Portes, Aparicio and Haller. It is based on an exploratory qualitative research project conducted in a medium-sized city in Catalonia that examined the integration of young people of different origins and the role religion played in this process. To do so, we proffer a religious discrimination hypothesis: a scenario in which Islam, but not other religions, can become a significant barrier to positive assimilation. According to the results, this ‘religious stigma’ scenario occurs in the majority of the young Muslims who were interviewed and across many aspects of their lives.
Zoning and affordability: A reply to Rodríguez-Pose and Storper
Authors: Manville Michael , Lens Michael , Monkkonen Paavo
Published: August 2020

Would increasing allowable housing densities in expensive cities generate more housing construction and make housing more affordable? In a provocative article, Andrés Rodríguez-Pose and Michael Storper survey the evidence and answer no. Restrictions on housing density, they contend, do not substantially influence housing production or price. They further argue that allowing more density in growing metropolitan areas would only improve housing outcomes for the affluent, and most likely harm the poor. We take issue with both of these contentions. While uncertainties remain in the study of housing prices and land use regulation, neither theory nor evidence warrant dispensing with zoning reform, or concluding that it could only be regressive. Viewed in full, the evidence suggests that increasing allowable housing densities is an important part of housing affordability in expensive regions.
Response to oxygen therapy using oxygen concentrators run off solar power in children with respiratory distress in remote primary health facilities in Papua New Guinea
Authors: Pulsan Francis , Duke Trevor
Published: August 2020

Oxygen therapy reduces mortality and morbidity from hypoxaemia in children. There are no published studies assessing individual patient responses to oxygen when delivered by oxygen concentrators in primary healthcare facilities.

Ours was a prospective observational study in remote health facilities over three years. A data recording form was used for children who required oxygen. Oxygen saturation (SpO2) was recorded before administration of oxygen, at 30 min and then daily. We assessed the primary diagnosis and the outcome.

The common primary diagnoses needing oxygen were pneumonia: moderate (39%) and severe (37%). The median SpO2 before administration of oxygen in 913 patients was 80% (interquartile range [IQR] 66%–88%), and by five days, for the 121 patients who were recorded, SpO2 was 97% (IQR 93%–98%). Of the 745 patients with a recorded outcome, 99% had an uneventful recovery.

We conclude that oxygen concentrators are effective in treating children in rural health facilities in Papua New Guinea.
Large deformation of TPU re-entrant auxetic structures designed by TO approach
Authors: Taherkhani Bahman , Anaraki Ali Pourkamali , Kadkhodapour Javad , Rezaei Saeed , Tu Haoyun
Published: August 2020

Auxetic materials are a family of rationally designed artificial structures that have unique effective properties gained from the distribution of the internal architecture rather than of the chemical composition. This article used the modified solid isotropic material with penalization method for topology optimization of 2D re-entrant auxetic structures with different Poisson’s ratios and volume fractions. The obtained structures were verified by the finite-element method (FEM) using the commercial FEM software and also validated by the experimental approach. A good agreement was achieved between the experimental and numerical results. Then, the cell geometry effect on Poisson’s ratio under large tension was investigated. Our study revealed that the location and stiffness of rotation joints are two new parameters affecting Poisson’s ratio value. Poisson’s ratio will decrease by decreasing the stiffness of rotation joints and positioning the rotation joints closer to the middle of the structure. So, from the investigation of the optimizer performance, it was achieved that re-entrant auxetic structures with different Poisson’s ratios could be easily designed by changing just the location of rotation joints. This will be applicable in many applications like sensor field.
From Strategic Leaders to Societal Leaders: On the Expanding Social Role of Executives and Boards
Authors: Krause Ryan , Miller Toyah L.
Published: August 2020

Scholarship on strategic leadership and governance has long operated under the assumption that strategic leaders’ influence and purview are predominantly constrained by organizational boundaries. Recent events and social movements have called this limited view of strategic leadership into question, however. In this editorial commentary, we explore the emerging trend of strategic leaders becoming—in both their own and stakeholders’ perceptions—societal leaders advancing social change inside and outside their organizations. We examine the research implications of taking a broader view of these leaders’ responsibility, one that reflects evolving social expectations.
Perspective on Adversity in Toxicology Evaluations
Authors: Engelhardt Jeffery A. , Dorato Michael A.
Published: August 2020

Determining adversity of effects in toxicology studies continues to pose a dilemma to practicing toxicologists and pathologists. How this determination is made may follow either a focused or broad approach to assessing the study data. The choice of which approach is best is dependent on a variety of factors. Therefore, we present a philosophical perspective on the determination of adversity across toxicology studies that may be applied in inhalation studies and those conducted by other routes of exposure.
Comparative Study of Endoscopic and Microscopic Type I Tympanoplasty in Terms of Delayed Facial Palsy
Authors: Li Kuan‐Hui , Chan Leong‐Perng , Chen Chin‐Kuo , Kuo Shin‐Huei , Wang Ling‐Feng , Chang Ning‐Chia , Wang Hsun‐Mo , Ho Kuen‐Yao , Chien Chen‐Yu
Published: August 2020

Objective

Delayed facial palsy is a complication of otologic surgery. Tympanoplasty is commonly employed in chronic otitis media. We compared the incidence and characteristics of delayed facial palsy and hearing restoration between endoscopic and microscopic tympanoplasty for the treatment of simple chronic otitis media.

Study Design

Retrospective cohort study.

Setting

Tertiary medical center.

Subjects and Methods

We retrospectively analyzed 468 patients who underwent type I tympanoplasty from January 2009 to April 2017. Patients were divided into transcanal endoscopic ear surgery and microscopic ear surgery groups. Their epidemiological profiles were reviewed and the outcomes of tympanoplasty were analyzed. Blood sample tests for herpes simplex virus and varicella‐zoster virus immunoglobulin M and immunoglobulin G were arranged in patients with delayed facial palsy.

Results

Transcanal endoscopic ear surgery exhibited similar benefits to microscopic ear surgery in graft‐taking rate and hearing restoration but had a shorter operation time (P <. 01). Eight patients (1.71%) developed delayed facial palsy, but no statistically significant difference was observed between the 2 surgical approaches. All patients tested negative for varicella‐zoster virus and herpes simplex virus immunoglobulin M and positive for immunoglobulin G of the same viruses; however, the titer did not exhibit a 4‐fold increase, implying that patients did not have active viral infections.

Conclusion

Transcanal endoscopic ear surgery is an ideal alternative for simple tympanoplasty. The incidence of delayed facial palsy was not significantly different between the 2 approaches. Because of the favorable prognosis and the absence of direct serological evidence supporting viral reactivation, treatment with antivirals may not be required.
Nonopioid, Multimodal Analgesia as First‐line Therapy After Otolaryngology Operations: Primer on Nonsteroidal Anti‐inflammatory Drugs (NSAIDs)
Authors: Cramer John D. , Barnett Michael L. , Anne Samantha , Bateman Brian T. , Rosenfeld Richard M. , Tunkel David E. , Brenner Michael J.
Published: August 2020

Objective

To offer pragmatic, evidence‐informed advice on nonsteroidal anti‐inflammatory drugs (NSAIDs) as first‐line therapy after surgery. This companion to the American Academy of Otolaryngology–Head & Neck Surgery (AAO‐HNS) clinical practice guideline (CPG), “Opioid Prescribing for Analgesia After Common Otolaryngology Operations,” presents data on potency, bleeding risk, and adverse effects for ibuprofen, naproxen, ketorolac, meloxicam, and celecoxib.

Data Sources

National Guidelines Clearinghouse, CMA Infobase, National Library of Guidelines, NICE, SIGN, New Zealand Guidelines Group, Australian National Health and Medical, Research Council, TRIP database, PubMed, Guidelines International Network, Cochrane Library, EMBASE, CINAHL, BIOSIS Previews, ISI Web of Science, AHRQ, and HSTAT.

Review Methods

AAO‐HNS opioid CPG literature search strategy, supplemented by PubMed/MEDLINE searches on NSAIDs, emphasizing systematic reviews and randomized controlled trials.

Conclusion

NSAIDs provide highly effective analgesia for postoperative pain, particularly when combined with acetaminophen. Inconsistent use of nonopioid regimens arises from common misconceptions that NSAIDs are less potent analgesics than opioids and have an unacceptable risk of bleeding. To the contrary, multimodal analgesia (combining 500 mg acetaminophen and 200 mg ibuprofen) is significantly more effective analgesia than opioid regimens (15 mg oxycodone with acetaminophen). Furthermore, selective cyclooxygenase‐2 inhibition reliably circumvents antiplatelet effects.

Implications for Practice

The combination of NSAIDs and acetaminophen provides more effective postoperative pain control with greater safety than opioid‐based regimens. The AAO‐HNS opioid prescribing CPG therefore prioritizes multimodal, nonopioid analgesia as first‐line therapy, recommending that opioids be reserved for severe or refractory pain. This state‐of‐the‐art review provides strategies for safely incorporating NSAIDs into acute postoperative pain regimens.
Effect of Tai Chi on post-stroke non-motor disorders: a systematic review and meta-analysis of randomized controlled trials
Authors: Lyu Diyang , Wang Jichen , Yang Fan , Zhang Yong , Zhang Weijiao , Liu Hongwei , Lyu Xuanxin , Fang Boyan
Published: August 2020

Objective:

To evaluate the state of evidence for the beneficial and harmful effects of Tai Chi on non-motor disorders in post-stroke patients.

Design:

Systematic review and meta-analysis of published studies.

Subjects:

Stroke survivors who received conventional rehabilitation therapy or Tai Chi training.

Data sources:

We searched seven electronic literature databases and one clinical registry platform to collect data from randomized controlled trials published up to July 26, 2020.

Results:

A total of 11 randomized controlled trials with 723 stroke survivors met the inclusion criteria, of which six were included in the meta-analysis. Among the 11 studies, one was assessed as “low”, eight were assessed as “moderate”, and only two were assessed as “high” for the assessment of methodologic quality. Compared to patients who received conventional rehabilitation therapy, those who received Tai Chi training showed greater improvement in scores of depression (standardized mean difference (SMD) [95% confidence interval (CI)] = 0.36 [0.10, 0.61], Grading of Recommendations Assessment, Development, and Evaluation [GRADE]: very low). There were no differences in the improvements in post-stroke global mental disorders (mean difference (MD [95% CI] = 6.15 [−3.05, 15.36], GRADE: moderate) or sleep disorders (MD [95% CI] = 0.33 [−1.51, 1.81], GRADE: low) between Tai Chi and control groups.

Conclusion:

Tai Chi may alleviate post-stroke depression in stroke survivors but has no clear effects on post-stroke cognitive and sleep disorders.
Reduced parenchymal cerebral blood flow is associated with greater progression of brain atrophy: The SMART-MR study
Authors: Ghaznawi Rashid , Zwartbol Maarten HT , Zuithoff Nicolaas PA , Bresser Jeroen de , Hendrikse Jeroen , Geerlings Mirjam I ,   on behalf of the UCC-SMART Study Group
Published: August 2020

Global cerebral hypoperfusion may be involved in the aetiology of brain atrophy; however, long-term longitudinal studies on this relationship are lacking. We examined whether reduced cerebral blood flow was associated with greater progression of brain atrophy. Data of 1165 patients (61 ± 10 years) from the SMART-MR study, a prospective cohort study of patients with arterial disease, were used of whom 689 participated after 4 years and 297 again after 12 years. Attrition was substantial. Total brain volume and total cerebral blood flow were obtained from magnetic resonance imaging scans and expressed as brain parenchymal fraction (BPF) and parenchymal cerebral blood flow (pCBF). Mean decrease in BPF per year was 0.22% total intracranial volume (95% CI: –0.23 to –0.21). Mean decrease in pCBF per year was 0.24 ml/min per 100 ml brain volume (95% CI: –0.29 to –0.20). Using linear mixed models, lower pCBF at baseline was associated with a greater decrease in BPF over time ( p =  0.01). Lower baseline BPF, however, was not associated with a greater decrease in pCBF ( p =  0.43). These findings indicate that reduced cerebral blood flow is associated with greater progression of brain atrophy and provide further support for a role of cerebral blood flow in the process of neurodegeneration.
Increases in Emotional Eating During Early Adolescence and Associations With Appearance Teasing by Parents and Peers, Rejection, Victimization, Depression, and Social Anxiety
Authors: Webb Haley J. , Kerin Jessica L. , Zimmer-Gembeck Melanie J.
Published: August 2020

Emotional eating, defined as eating in response to affect, may increase during early adolescence, a time of heightened emotionality and increased prevalence of emotional disorders. We investigated change in emotional eating, while also testing the influence of social–emotional risk factors. Study participants ( N = 379, mean age [ Mage] = 12.0 years; 56% girls) completed measures of emotional eating twice over 1 year and reported on social adversity within peer and parent contexts (i.e., appearance teasing by peers and parents, and peer rejection) and depression and social anxiety symptoms. Relational victimization and peer rejection, measured via classmate-reports, were also examined as correlates of emotional eating. Emotional eating increased, on average, for Grade 6 and 7 students, marginally increased in Grade 5 students, and increased in boys and girls. In a multivariate prospective model, appearance teasing by parents and social anxiety symptoms were prospectively associated with a higher level of emotional eating 1 year later.
Quantified small bowel motility in patients with ulcerative colitis and gastrointestinal symptoms: a pilot study
Authors: Tufvesson Hanna , Dreja Julia , Ekberg Olle , Leander Peter , Månsson Sven , Ohlsson Bodil
Published: August 2020

Background

Gastrointestinal (GI) symptoms are common in patients with ulcerative colitis (UC), even when the disease is in remission, possibly due to abnormalities in GI motility. Small bowel motility can be assessed globally and in specific intestinal regions during magnetic resonance enterography (MRE) using a displacement mapping technique.

Purpose

To investigate whether small bowel motility in MRE differs between patients with UC and controls, and if altered motility correlates with GI symptoms.

Material and Methods

In 2016–2018, patients who were admitted for MRE, regardless of clinical indication, were consecutively invited to the study. Healthy volunteers were recruited. The participants completed a questionnaire regarding GI symptoms and relevant clinical data were reviewed in the medical records. The dynamic imaging series obtained during MRE were sent for motility mapping and a motility index (MI) was calculated in jejunum, ileum and terminal ileum in all participants.

Results

In total, 224 patients and healthy volunteers were enrolled in the study. Fifteen were diagnosed with UC and 22 were considered healthy controls. In UC, the prevalence of GI symptoms was higher than in controls ( P < 0.001), both in remission and in active disease. There was no correlation between GI symptoms and small bowel motility in UC. Jejunal motility was lower in UC than in controls ( P = 0.049).

Conclusion

Jejunal motility is decreased in UC compared with healthy controls, but there is no relationship between small bowel motility and GI symptoms in UC.
A case of a vaginal Brenner tumor without a gland mimicking a borderline tumor: unusual morphology and diagnostic pitfalls
Authors: Zhang Qin , Tian Can , Wang Kun , Xin Qi , Shen Yan , Zhang Chuan-shan , Ma Zhe
Published: August 2020

Brenner tumor is a rare neoplasm of the vagina. This tumor is diagnosed according to the criteria of ovarian tumors. We report here a 64-year-old postmenopausal woman with a 2.0-cm sessile vaginal polyp for 9 years. Microscopic examination showed unusual features of no gland appearing in the tumor, but the other two characteristic components of transitional islands and dense fibrous stroma were observed. The tumor was diagnosed as a vaginal Brenner tumor on the basis of the definition proposed by the World Health Organization classification of female reproductive organ tumors. In our case, part of the epithelial nests of the Brenner tumor showed basaloid cell differentiation with peripheral palisading, and irregular papillary hyperplasia was observed around the epithelial nests similar to a borderline tumor. However, no mitotic activity or nuclear atypia was present in either the epithelial or stromal components. The presence of epithelial nests requires attention in the medical history of the patient. Our patient did not have a history of primary urothelial carcinoma. Our patient’s benign vaginal Brenner tumor with different morphological characteristics supports the current notion that Walthard nests might act as possible precursor lesions.
Extramedullary melanotic schwannoma recurrence in the cervical vertebral arch: a case report and review of the literature
Authors: Hou Zongbin , Shi Teng , Li Guangrun , Tian Lin , Li Xinna , Liu Xiaoyang
Published: August 2020

Melanotic schwannoma (MS), a slowly growing nerve sheath tumor, is not a purely benign tumor. MS accounts for less than 1% of all nerve sheath tumors. We herein describe a rare case of MS and present a literature review focusing on the treatment of this disease. Twelve years before presentation at our hospital, a 41-year-old woman was examined because of an 8-month history of neck pain and 6-month history of upper extremity numbness and weakness. She underwent surgery to remove a tumor, and the pathological examination confirmed a diagnosis of MS. Twelve years later, at 53 years of age, the patient presented to our hospital with a 2-year history of neck pain and upper extremity numbness and weakness. Posterior cervical tumor resection was performed along with posterior cervical laminectomy, decompression and intraspinal space-occupying internal fixation, and radiotherapy. MS recurrence was confirmed. No tumor recurrence or metastasis was found after 7 months of follow-up. Recurrence of MS is rare, and its diagnosis depends on pathological features. Radical excision is the primary treatment for MS. Incomplete resection of MS is a risk factor for postoperative recurrence and metastasis. Furthermore, postoperative adjuvant radiotherapy should be performed to prevent recurrence and metastasis of MS.