bluuebunny/crossref_metadata_2025 huggingface dataset:
La regla de la ‘prevalencia de las condiciones particulares sobre las condiciones generales’. Su proyección en el ámbito de la interpretación de los contratos, y en especial en el contrato de seguro
Authors: Jaramillo Jaramillo Carlos Ignacio
Published: March 2018

En el ámbito del Derecho de contratos, por excelencia, uno de los temas de mayor resonancia y también vigencia, es el atinente a la interpretación contractual, no sólo en lo que atañe a los llamados contratos de libre discusión o paritarios, sino también, y de modo sobresaliente, frente a los denominados contratos de contendido predispuesto, contratos por adhesión a condiciones generales, y contratos de consumo, entre otras manifestaciones de la contratación contemporánea. Por consiguiente, examinar las modernas reglas de interpretación de los contratos en el Derecho comparado y en el colombiano, resulta de la mayor utilidad, en concreto la arraigada ‘regla de la prevalencia de las condiciones particulares sobre las condiciones generales’, núcleo de la contratación en la actualidad, tanto desde una perspectiva general, como desde una perspectiva individual, en especial en la esfera reservada al contrato de seguro, en el que la pauta en comento, ciertamente, reviste singular importancia, hasta el punto de que buen aparte de su estructuración y desarrollo ulterior, en efecto, ha tenido lugar en sede de la dinámica y enriquecida relación aseguraticia.
Propeller Innovation Takes Off
Authors: O’Heir Jeff
Published: March 2018

This article demonstrates events that bring revolution in propeller design and innovation. Propeller design has changed in only small increments since 1903. Design changes incrementally in mainstream aviation, and major design innovations are rare. The mechanical and aerospace engineers who design propellers are innovating again. In propeller design, high power and low pitch are ideal for take-off, while higher pitch and lower power are ideal for high-altitude cruising. In order to meet these conflicting demands, a variable pitch mechanism is used to automatically control the blades’ pitch in flight. While new materials are important, engineers say faster, cheaper computers, along with the nearly limitless hardware and software resources in the cloud, have contributed the most to propeller design. Affordable technology is also allowing many small companies to compete against the big boys and take risks that were once far too expensive and risky to attempt.
At the Intersection
Authors: Lieuwen Timothy C. , Thole Karen A.
Published: March 2018

This article highlights the role that advanced manufacturing will play as industry makes large investments. Advanced manufacturing can play a pivotal role in improving performance and reducing costs. This manufacturing may enable higher turbine inlet temperatures, new materials and coatings, improved cooling, and better sealing and three-dimensional aerodynamics to reduce losses. It can also achieve increased performance and operability through the integration of sensors in turbine components. The certification processes for components also needs attention. Without clear policies, the tremendous opportunities for the aftermarket repair business may result in intellectual property battles where lines can easily be blurred given the digitization of parts. Redesigning turbine airfoils presents tremendous opportunities to route valuable cooling air to regions where it was not previously possible to cool in an effective manner. The gas turbine is poised to become the most important thermal energy and propulsion device in the 21st century. Advanced manufacture will significantly alter how gas turbines are made and perhaps how they operate.
The More You See
Authors: Thilmany Jean
Published: March 2018

This study discusses about the future of augmented reality (AR) and its capability to transform engineering design. AR lets designers visualize parts such as the motorcycle cladding, fuel-tank cover, and seal. AR’s possibilities have spurred major engineering software companies such as Bentley Systems, Siemens PLM, and Autodesk, and even the software behemoth Microsoft, to invest in AR for engineering, manufacturing, and plant design. Merging engineering software and AR could let engineers suspend 3D models in midair and tweak them in real time. In AR’s new era, wearable headsets are smaller, less bulky, and far more user friendly than older AR devices. They are also reliable, affordable, and do not tie their wearers by cord to a computer system. New AR applications have let auto mechanics gaze through headsets for visual guidance as they repaired car engines. It is predicted that AR will also be useful for the Internet of Things and the Industrial Internet of Things.
Power Prosthetics
Authors: Goudarzi Sara , Romer Thomas
Published: March 2018

This article presents an overview of the bionic limbs designed by Hugh Herr. They include the powered foot and ankle prostheses with multiple tendon-like actuators that stiffen and power gait. Each ankle holds three computers that perform various computations enabling one to walk at different speeds across different terrains. They were distinct in the prostheses world because these bionic limbs are powered, while all other foot ankle prostheses are energetically passive. In effect, Herr has to mimic the mechanism of a natural limb. The bionic limb is running spinal-like reflexes on a computer chip. A commercial product—called emPOWER—is being sold through Herr’s startup called BioneX Medical Technologies. In the lab, Herr and his colleagues are working on developing neural interfaces, essentially connecting the bionic limbs to muscles and nerves so a person can think and move the limbs and also feel the movement as a feedback into the nervous system.
Additive Advantage
Authors: Gibson Tom , Romer Thomas
Published: March 2018

This article describes the basic features of a 3D printed blade that can survive inside a turbine. This blade has been developed by Siemens. The team behind the blade included project manager, Jenny Nilsson, as well as engineers at Material Solutions, a company Siemens later bought. Team members developed better cooling designs to improve the gas turbine efficiency, designed the blade, and developed the whole manufacturing process to manufacture this type of component and geometry. Like all additive manufacturing, the team applied thin layers of material—one after the other—to build up a finished object. The main difference with Siemens’ blade process was that layers were made of high-temperature-resistant, polycrystalline nickel-based superalloy powder, which was then heated and melted by a laser. The durability of the printed blades was proved by installing them in a 13-MW SGT-400-type industrial gas turbine at a Siemens test center for industrial gas turbines in Lincoln, United Kingdom.
Power Suit
Authors: Gibson Tom
Published: March 2018

This article explores the research and development work of developing exoskeletons that would assist soldiers in carrying heavy loads across long distances. Much of the funding for soft exoskeletons has come through Defense Advanced Research Projects Agency (DARPA), which has the goal of helping soldiers walk long distances while carrying a heavy load. An exosuit that reduces the physical toll on soldiers can improve the Army’s war-fighting capability. The exosuits are robotic external skeletons made of soft, lightweight, and flexible material so that people can wear them like the Spandex athletic wear. Once these suits exit the lab, they could support soldiers as they walk or increase their endurance. Flexible powered suits could provide assistance during walking, hiking, running, and other sporting activities. Similar suits could be programmed to compensate for the limited strength and coordination of someone recovering from an injury or managing with a debilitating illness. The slimmer profile of the soft exosuits will enable them to be more seamlessly incorporated in work settings.
Rebel Heart
Authors: Sukel Kayt
Published: March 2018

This article discusses features and advantages of BiVACOR, an artificial heart machine. It also presents a brief overview of medical successes of Billy Cohn, a medical doctor. The BiVACOR heart is a rotary pump with a single moving part that consists of two impellers on a magnetically suspended rotor. Cohn along with his older brother built homemade gadgets, rocket engines, and a variety of incendiary devices in the garage. As Cohn progressed in his medical career, he never stopped tinkering. He was fast becoming one of the finest heart surgeons in the country, yet he spent his free time in his home workshop, prototyping medical devices to assist his operations. Cohn and O.H. ‘Bud’ Frazier, a cardiac surgeon who had performed more than 1000 heart transplants, led the work on AbioCor from the Texas Heart Institute in Houston and worked on a completely novel approach to artificial heart design—continuous flow. The heart, built by the two surgeons, is set out to build would replace those metaphorical flappy wings with fixed ones.
Damage Assessment in Composite Beam Using Infrared Thermography, Optical Sensors, and Terahertz Technique
Authors: Soman Rohan N. , Majewska Katarzyna , Mieloszyk Magdalena , Ostachowicz Wieslaw
Published: March 2018

Composite materials find wide range of applications due to their high strength-to-weight ratio. Due to this increasing dependence on composite materials, there is a need to study their mechanical behavior in case of damage. There are several extended nondestructive testing (ENDT) and structural health-monitoring (SHM) methods for the assessment of the mechanical properties each with their set of advantages and disadvantages. This paper presents a comparative study of three distinct damage detection methods (infrared thermography (IRT), neutral axis (NA) method based on optical strain sensor measurements, and terahertz spectroscopy) for the detection of delamination and temperature-induced damage in a simple glass fiber reinforced polymer (GFRP) beamlike structure. The terahertz spectroscopy is a specialized technique suitable for detecting deterioration inside the structure but has limited application for in-service performance monitoring. Similarly, the IRT technique in the active domain may be used for in situ monitoring but not in in-service assessment. Both methods allow the visualization of the internal structure and hence allow identification of the type and the extent of damage. Fiber optic sensors (especially fiber Bragg grating (FBG)) due to their small diameter and no need of calibration can be permanently integrated within the sample and applied for continuous dynamic strain measurements. The measured strain is treated as an input for neutral axis (NA) method, which as a damage-sensitive feature may be used for in-service monitoring but gives absolutely no information about the type and extent of damage. The results for damage detection based on proposed comparative studies give a complete description of the analyzed structure.
The Effect of Manufacturing Variations on Unsteady Interaction in a Transonic Turbine
Authors: Clark John P. , Beck Joseph A. , Kaszynski Alex A. , Still Angela , Ni Ron-Ho
Published: March 2018

This effort focuses on the comparison of unsteadiness due to as-measured turbine blades in a transonic turbine to that obtained with blueprint geometries via computational fluid dynamics (CFD). A Reynolds-averaged Navier–Stokes flow solver with the two-equation Wilcox turbulence model is used as the numerical analysis tool for comparison between the blueprint geometries and as-manufactured geometries obtained from a structured light optical measurement system. The nominal turbine CFD grid data defined for analysis of the blueprint blade were geometrically modified to reflect as-manufactured turbine blades using an established mesh metamorphosis algorithm. The approach uses a modified neural network to iteratively update the source mesh to the target mesh. In this case, the source is the interior CFD surface grid while the target is the surface blade geometry obtained from the optical scanner. Nodes interior to the CFD surface were updated using a modified iterative spring analogy to avoid grid corruption when matching as-manufactured part geometry. This approach avoids the tedious manual approach of regenerating the CFD grid and does not rely on geometry obtained from coordinate measurement machine (CMM) sections, but rather a point cloud representing the entirety of the turbine blade. Surface pressure traces and the discrete Fourier transforms (DFT) thereof from numerical predictions of as-measured geometries are then compared both to blueprint predictions and to experimental measurements. The importance of incorporating as-measured geometries in analyses to explain deviations between numerical predictions of blueprint geometries and experimental results is readily apparent. Further analysis of every casting produced in the creation of the test turbine yields variations that one can expect in both aero-performance and unsteady loading as a consequence of manufacturing tolerances. Finally, the use of measured airfoil geometries to reduce the unsteady load on a target blade in a region of interest is successfully demonstrated.
Recent Trends and Developments in Transition Metal Dichalcogenide Photoelectrodes for Solar-to-Hydrogen Conversion
Authors: Prabhakar Vattikuti S. V.
Published: March 2018

The design of efficient devices for the photoelectrochemical (PEC) water splitting for solar-to-hydrogen (STH) processes has gained much attention because of the fossil fuels crisis. In PEC water splitting, solar energy is converted to a chemical fuel for storage. From the viewpoint of economics and large-scale application, semiconductor photoelectrodes with high stability and efficiency are required. However, although numerous materials have been discovered, challenges remain for their commercialization. Among the enormous number of investigated materials, layered transition metal dichalcogenide (TMD)-based photoelectrodes show attractive performance in PEC devices owing to their suitable narrow bandgaps, high absorption capacity, and fast carrier transport properties. A comprehensive review of TMDs photoelectrodes for STH processes would help advance research in this expanding research area. This review covers the physicochemical features and latest progress in various layered-structure TMD-based photoelectrodes, especially MoS2, as well as various approaches to improve the PEC performance and stability by coupling with active carbon materials, including graphene, CNTs, and conductive carbon. Finally, we discuss the prospects and potential applications for STH processes. This review paper gives insights into the fundamental concepts and the role of active chemical species during the STH conversion processes and their influence in enhancing PEC water splitting performance.
Engine-Control Impact on Energy Balances for Two-Stroke Engines for 10–25 kg Remotely Piloted Aircraft
Authors: Ausserer Joseph K. , Polanka Marc D. , Litke Paul J. , Baranski Jacob A.
Published: March 2018

The rapid expansion of the market for remotely piloted aircraft (RPA) includes a particular interest in 10–25 kg vehicles for monitoring, surveillance, and reconnaissance. Power-plant options for these aircraft are often 10–100 cm3 internal combustion engines (ICEs). The present study builds on a previous study of loss pathways for small, two-stroke engines by quantifying the trade space among energy pathways, combustion stability, and engine controls. The same energy pathways are considered in both studies—brake power, heat transfer from the cylinder, short circuiting, sensible exhaust enthalpy, and incomplete combustion. The engine controls considered in the present study are speed, equivalence ratio, combustion phasing (ignition timing), cooling-air flow rate, and throttle. Several options are identified for improving commercial-off-the-shelf (COTS)-engine efficiency and performance for small, RPA. Shifting from typical operation at an equivalence ratio of 1.1–1.2 to lean operation at an equivalence ratio of 0.8–0.9 results in a 4% (absolute) increase in fuel-conversion efficiency at the expense of a 10% decrease in power. The stock, linear timing maps are excessively retarded below 3000 rpm, and replacing them with custom spark timing improves ease of engine start. Finally, in comparison with conventional-size engines, the fuel-conversion efficiency of the small, two-stroke ICEs improves at throttled conditions by as much as 4–6% (absolute) due primarily to decreased short-circuiting. When no additional short-circuiting mitigation techniques are employed, running a larger engine at partial throttle may lead to an overall weight savings on longer missions. A case study shows that at 6000 rpm, the 3W-55i engine at partial throttle will yield an overall weight saving compared to the 3W-28i engine at wide-open throttle (WOT) for missions exceeding 2.5 h (at a savings of ∼5 g/min).
Design, Modeling, and Integration of a Flexible Universal Spatial Robotic Tail
Authors: Rone William S. , Saab Wael , Ben-Tzvi Pinhas
Published: March 2018

This paper presents the novel design of a bioinspired robot capable of generating spatial loading relative to its base. By looking to nature at how animals utilize their tails, a bioinspired structure is developed that utilizes a redundant serial chain of rigid links to mimic the continuous deformation of a biological tail. Individual links are connected by universal joints to enable a spatial robot workspace capable of generating spatial loading comprised of pitch, yaw, and roll direction contributions. Two sets of three cables are used to create two actuated segments along the robot. A dynamic model of the robot is derived using prescribed cable displacement trajectories as inputs to determine the resulting joint angle trajectories and cable tensions. Sensors are integrated on-board the robot to calculate joint angles and joint velocities in real-time for use in feedback control. The loading capabilities of the robot are analyzed, and an experimental prototype is integrated and demonstrated.
On Improvement of the Frequency Bandwidth of Nonlinear Vibration Energy Harvesters Using a Mechanical Motion Rectifier
Authors: Tai Wei-Che , Liu Mingyi , Yuan Yue , Zuo Lei
Published: March 2018

This paper presents a broadband vibration energy harvester (VEH) which consists of a monostable Duffing oscillator connected to an electromagnetic generator via a mechanical motion rectifier. The mechanical motion rectifier converts the bidirectional vibratory motion of the oscillator induced by ambient environment vibrations into unidirectional rotation of the generator and causes the harvester to periodically switch between a large- and small-inertia system, resulting in nonlinearity in inertia. By means of analytical and numerical methods, this inertia nonlinearity is shown to have two advantages. First, it allows for more stiffness nonlinearity without inducing nonuniqueness of energy branches and enhances bandwidths of energy harvesting. The effect of mitigating nonuniqueness of energy branches occurs to steady-state and transient responses of the harvester and is experimentally verified by a prototype. The experimental results show a nearly 50% increase in the half power bandwidth via mechanical motion rectification (MMR). Second, it enlarges the basin of attraction of the high-energy branch when multiple energy branches are present. A numerical example shows that a more than 50% increase in the basin area can be achieved via MMR.
Seismic Performance Evaluation of Liquid Storage Tanks Using Nonlinear Static Procedures
Authors: Bakalis Konstantinos , Kazantzi Athanasia K. , Vamvatsikos Dimitrios , Fragiadakis Michalis
Published: March 2018

A simplified approach is presented for the seismic performance assessment of liquid storage tanks. The proposed methodology relies on a nonlinear static analysis, in conjunction with suitable “strength ratio-ductility-period” relationships, to derive the associated structural demand for the desired range of seismic intensities. In the absence of available relationships that are deemed fit to represent the nonlinear-elastic response of liquid storage tanks, several incremental dynamic analyses are performed for variable post-yield hardening ratios and periods in order to form a set of data that enables the fitting of the response. Following the identification of common modes of failure such as elephant's foot buckling (EFB), base plate plastic rotation, and sloshing wave damage, the aforementioned relationships are employed to derive the 16%, 50%, and 84% percentiles for each of the respective response parameters. Fragility curves are extracted for the considered failure modes, taking special care to appropriately quantify both the median and the dispersion of capacity and demand. A comparison with the corresponding results of incremental dynamic analysis (IDA) reveals that the pushover approach offers a reasonable agreement for the majority of failure modes and limit states considered.
Design and Characterization of a Trailer-Based Horizontal-Axis Wind Turbine Test Rig
Authors: Khorsand Iman , Dallas Cameron , Magni Alan , Crawford Curran
Published: March 2018

This paper presents a mobile testing rig developed for small wind turbine (SWT) experimental work to orchestrate, cost-effectively, turbine performance characterization in both controlled wind inflow speeds and turbulent ambient flows. It facilitates off-grid testing of up to a 1 kW wind turbine. It is a dual-purpose machine that can be towed behind a vehicle to conduct steady-state tests (track testing) or be parked to collect unsteady field data (field testing), all with the same rotor and instrumentation. Its mechanical design included computational fluid dynamics (CFD) analysis to gauge the potential impact of towing vehicle disturbance on the free stream available to the rotor. To provide a compelling platform for full rotor speed control, a reconfigurable control system coupled to an electric vehicle controller with regenerative braking technology has been modeled and implemented into its electrical design. Uncertainty analysis has also been rigorously conducted to project the error bounds pertaining to both precision and bias components of the testing results. The rig has been tested in a towed scenario and blade element momentum (BEM) simulations have been compared with the actual aggregate performance curves obtained experimentally. Future work involves testing in unsteady winds, for which the rig was ultimately designed in order to better understand unsteady rotor performance and adaptive design.
Expanded health systems for sustainable development
Authors: Dye Christopher
Published: March 2018

Advance transformative research for the 2030 agenda
Are wood pellets a green fuel?
Authors: Schlesinger William H.
Published: March 2018

A return to firewood is bad for forests and for the climate
Dynamics in Copy Numbers of Five Plasmids of a Dairy Lactococcus lactis Strain under Dairy-Related Conditions Including Near-Zero Growth Rates
Authors: van Mastrigt Oscar , Lommers Marcel M. A. N. , de Vries Yorick C. , Abee Tjakko , Smid Eddy J.
Published: March 2018

Lactic acid bacteria can carry multiple plasmids affecting their performance in dairy fermentations. The expression of plasmid-borne genes and the activity of the corresponding proteins are severely affected by changes in the numbers of plasmid copies. We studied the impact of growth rate on the dynamics of plasmid copy numbers at high growth rates in chemostat cultures and down to near-zero growth rates in retentostat cultures. Five plasmids of the dairy strain
Lactococcus lactis
FM03-V1 were selected, and these varied in size (3 to 39 kb), in replication mechanism (theta or rolling circle), and in putative (dairy-associated) functions. The copy numbers ranged from 1.5 to 40.5, and the copy number of theta-type replicating plasmids was negatively correlated to the plasmid size. Despite the extremely wide range of growth rates (0.0003 h
−1
to 0.6 h
−1
), the copy numbers of the five plasmids were stable and only slightly increased at near-zero growth rates, showing that the plasmid replication rate was strictly controlled. One low-copy-number plasmid, carrying a large exopolysaccharide gene cluster, was segregationally unstable during retentostat cultivations, reflected in a complete loss of the plasmid in one of the retentostat cultures. The copy number of the five plasmids was also hardly affected by varying the pH value, nutrient limitation, or the presence of citrate (maximum 2.2-fold), signifying the stability in copy number of the plasmids.

IMPORTANCE
Lactococcus lactis
is extensively used in starter cultures for dairy fermentations. Important traits for the growth and survival of
L. lactis
in dairy fermentations are encoded by genes located on plasmids, such as genes involved in lactose and citrate metabolism, protein degradation, oligopeptide uptake, and bacteriophage resistance. Because the number of plasmid copies could affect the expression of plasmid-borne genes, it is important to know the factors that influence the plasmid copy numbers. We monitored the plasmid copy numbers of
L. lactis
at near-zero growth rates, characteristic for cheese ripening. Moreover, we analyzed the effects of pH, nutrient limitation, and the presence of citrate. This showed that the plasmid copy numbers were stable, giving insight into plasmid copy number dynamics in dairy fermentations.
A Proposed New Strain of Avian Picornavirus in Broiler Chicken from Brazil
Authors: Castro Ceyla Maria Oeiras , Chagas Elaine Hellen Nunes , Bezerra Delana Andreza Melo , Ribeiro Aline Farias , da Silva Sandro Patroca , Cruz Ana Cecília Ribeiro , Júnior Edivaldo Costa Sousa , Silva René Ribeiro , Mascarenhas Joana D’Arc Pereira
Published: March 2018

A new strain of avian picornavirus was identified in fecal samples from broiler chickens in a commercial farm in the municipality of Benevides, Pará, Brazil. Genomic analysis showed it to have a nucleotide identity of 78.4% with the family
Picornaviridae
, genus
Avisivirus,
and species
Avisivirus A
, suggesting that this is a possible new strain within this species.
Complete and Assembled Genome Sequence of Salmonella enterica subsp. enterica Serotype Senftenberg N17-509, a Strain Lacking Salmonella Pathogen Island 1
Authors: Stevens Marc J. A. , Zurfluh Katrin , Althaus Denise , Corti Sabrina , Lehner Angelika , Stephan Roger
Published: March 2018

The genome of
Salmonella enterica
subsp.
enterica
serotype Senftenberg N17-509, a strain isolated from desiccated coconut, was sequenced using single-molecule real-time sequencing. It consists of a 5.1-Mbp chromosome and a 29-kb linear plasmid.
Divergent Pathogenic Properties of Circulating Coxsackievirus A6 Associated with Emerging Hand, Foot, and Mouth Disease
Authors: Wang Shao-Hua , Wang Ao , Liu Pan-Pan , Zhang Wen-Yan , Du Juan , Xu Shuang , Liu Guan-Chen , Zheng Bai-Song , Huan Chen , Zhao Ke , Yu Xiao-Fang
Published: March 2018

Coxsackievirus A6 (CV-A6) is an emerging pathogen associated with hand, foot, and mouth disease (HFMD). Its genetic characterization and pathogenic properties are largely unknown. Here, we report 39 circulating CV-A6 strains isolated in 2013 from HFMD patients in northeast China. Three major clusters of CV-A6 were identified and related to CV-A6, mostly from Shanghai, indicating that domestic CV-A6 strains were responsible for HFMD emerging in northeast China. Four full-length CV-A6 genomes representing each cluster were sequenced and analyzed further. Bootscanning tests indicated that all four CV-A6-Changchun strains were most likely recombinants between the CV-A6 prototype Gdula and prototype CV-A4 or CV-A4-related viruses, while the recombination pattern was related to, yet distinct from, the strains isolated from other regions of China. Furthermore, different CV-A6 strains showed different capabilities of viral replication, release, and pathogenesis in a mouse model. Further analyses indicated that viral protein 2C contributed to the diverse pathogenic abilities of CV-A6 by causing autophagy and inducing cell death. To our knowledge, this study is the first to report lethal and nonlethal strains of CV-A6 associated with HFMD. The 2C protein region may play a key role in the pathogenicity of CV-A6 strains.

IMPORTANCE
Hand, foot, and mouth disease (HFMD) is a major and persistent threat to infants and children. Besides the most common pathogens, such as enterovirus A71 (EV-A71) and coxsackievirus A16 (CV-A16), other enteroviruses are increasingly contributing to HFMD. The present study focused on the recently emerged CV-A6 strain. We found that CV-A6 strains isolated in Changchun City in northeast China were associated with domestic origins. These Changchun viruses were novel recombinants of the CV-A6 prototype Gdula and CV-A4. Our results imply that measures to control CV-A6 transmission are urgently needed. Further analyses revealed differing pathogenicities in strains isolated in a neonatal mouse model. One of the possible causes has been narrowed down to the viral protein 2C, using phylogenetic studies, viral sequences, and direct tests on cultured human cells. Thus, the viral 2C protein is a promising target for antiviral drugs to prevent CV-A6-induced tissue damage.
Association of dispositional optimism with Life’s Simple 7’s Cardiovascular Health Index: results from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) Sociocultural Ancillary Study (SCAS)
Authors: Hernandez Rosalba , González Hector M , Tarraf Wassim , Moskowitz Judith T , Carnethon Mercedes R , Gallo Linda C , Penedo Frank J , Isasi Carmen R , Ruiz John Manuel , Arguelles William , Buelna Christina , Davis Sonia , Gonzalez Franklyn , McCurley Jessica L , Wu Donghong , Daviglus Martha L
Published: March 2018

Objectives

Mounting evidence links positive psychological functioning to restorative health processes and favourable medical outcomes. However, very little is known about the relationship between optimism, an indicator of psychological functioning and the American Heart Association (AHA)-defined concept of cardiovascular health (CVH), particularly in Hispanics/Latinos of diverse backgrounds. To address limitations of existing literature, this study investigated the association between dispositional optimism and CVH in a heterogeneous sample of Hispanics/Latinos residing in the USA.

Design

Cross-sectional study.

Participants and setting

Data were analysed from 4919 adults ages 18–75 of the Hispanic Community Health Study/Study of Latinos parent study and the Sociocultural Ancillary Study.

Main outcome measures

Optimism was assessed using the 6-item Life Orientation Test-Revised (range from 6 to 30). AHA classification standards were used to derive an additive CVH score with operationalisation of indicators as Ideal, Intermediate and Poor. The overall CVH score included indicators of diet, body mass index, physical activity, cholesterol, blood pressure, fasting glucose and smoking status. Multivariate linear and logistic regressions were used to examine associations of optimism with CVH (Life’s Simple 7), after adjusting for sociodemographic factors and depressive symptoms.

Results

Each increase in the optimism total score was associated with a greater CVH score (β=0.03 per unit increase, 95% CI 0.01 to 0.05). When modelling tertiles of optimism, participants with moderate (β=0.24 to 95% CI 0.06 to 0.42) and high (β=0.12, 95% CI 0.01 to 0.24) levels of optimism displayed greater CVH scores when compared with their least optimistic peers.

Conclusion

This study offers preliminary evidence for an association between optimism and CVH in a large heterogeneous group of Hispanic/Latino adults. Our study adds scientific knowledge of psychological assets that may promote CVH and suggests a novel therapeutic target for consideration. Future studies are needed to explore causality and potential mechanism underlying the relationship between positive emotion and heart health.
Patients and hospital managers want laparoscopic simulation training to become mandatory before live operating: a multicentre qualitative study of stakeholder perceptions
Authors: Preshaw Jessica , Siassakos Dimitrios , James Mark , Draycott Timothy , Vyas Sanjay , Burden Christy
Published: March 2018

Background

Surgical procedures are complex and susceptible to human error. Individual surgical skill correlates with improved patient outcomes demonstrating that surgical proficiency is vitally important for patient safety. Evidence demonstrates that simulation training improves laparoscopic surgical skills; however, projects to implement and integrate laparoscopic simulation into core surgical curricula have had varied success. One barrier to successful implementation has been the lack of awareness and prioritisation of simulation initiatives by key stakeholders.

Objective

To determine the knowledge and perceptions of patients and hospital managers on laparoscopic surgery and simulation training in patient safety and healthcare.

Method

A qualitative study was conducted in the Southwest of England. 40 semistructured interviews were undertaken with patients attending general gynaecology clinics and general surgical and gynaecology hospital managers.

Results

Six key themes identified included: positive expectations of laparoscopic surgery; perceptions of problems and financial implications of laparoscopic surgery; lack of awareness of difficulties with surgical training; desire for laparoscopic simulation training and competency testing for patient benefit; conflicting priorities of laparoscopic simulation in healthcare; and drawbacks of surgical simulation training. Patients and managers were largely unaware of the risks of laparoscopic surgery and challenges for training. Managers highlighted conflicting financial priorities when purchasing educational equipment. Patients stated that they would have greater confidence in a surgeon who had undertaken mandatory surgical simulation training and perceived purchasing simulation equipment to be a high priority in the National Health Services. Most patients and hospital managers believed trainees should pass an examination on a simulator prior to live operating.

Conclusions

Competency-based mandatory laparoscopic simulation was strongly supported by the majority of stakeholders to augment the initial learning curve of surgeons.
Thin-shell wormholes in rainbow gravity
Authors: Amirabi Z. , Halilsoy M. , Mazharimousavi S. Habib
Published: March 2018

At the Planck scale of length [Formula: see text] m where the energy is comparable with the Planck energy, the quantum gravity corrections to the classical background spacetime results in gravity’s rainbow or rainbow gravity. In this modified theory of gravity, geometry depends on the energy of the test particle used to probe the spacetime, such that in the low energy limit, it yields the standard general relativity. In this work, we study the thin-shell wormholes in the spherically symmetric rainbow gravity. We find the corresponding properties in terms of the rainbow functions which are essential in the rainbow gravity and the stability of such thin-shell wormholes are investigated. Particularly, it will be shown that there are exact solutions in which high energy particles crossing the throat will encounter less amount of total exotic matter. This may be used as an advantage over general relativity to reduce the amount of exotic matter.
Studying the Global Bifurcation Involving Wada Boundary Metamorphosis by a Method of Generalized Cell Mapping with Sampling-Adaptive Interpolation
Authors: Liu Xiao-Ming , Jiang Jun , Hong Ling , Tang Dafeng
Published: March 2018

In this paper, a new method of Generalized Cell Mapping with Sampling-Adaptive Interpolation (GCMSAI) is presented in order to enhance the efficiency of the computation of one-step probability transition matrix of the Generalized Cell Mapping method (GCM). Integrations with one mapping step are replaced by sampling-adaptive interpolations of third order. An explicit formula of interpolation error is derived for a sampling-adaptive control to switch on integrations for the accuracy of computations with GCMSAI. By applying the proposed method to a two-dimensional forced damped pendulum system, global bifurcations are investigated with observations of boundary metamorphoses including full to partial and partial to partial as well as the birth of fully Wada boundary. Moreover GCMSAI requires a computational time of one thirtieth up to one fiftieth compared to that of the previous GCM.
Coexistence of Multiple Attractors in an Active Diode Pair Based Chua’s Circuit
Authors: Bao Bocheng , Wu Huagan , Xu Li , Chen Mo , Hu Wen
Published: March 2018

This paper focuses on the coexistence of multiple attractors in an active diode pair based Chua’s circuit with smooth nonlinearity. With dimensionless equations, dynamical properties, including boundness of system orbits and stability distributions of two nonzero equilibrium points, are investigated, and complex coexisting behaviors of multiple kinds of disconnected attractors of stable point attractors, limit cycles and chaotic attractors are numerically revealed. The results show that unlike the classical Chua’s circuit, the proposed circuit has two stable nonzero node-foci for the specified circuit parameters, thereby resulting in the emergence of multistability phenomenon. Based on two general impedance converters, the active diode pair based Chua’s circuit with an adjustable inductor and an adjustable capacitor is made in hardware, from which coexisting multiple attractors are conveniently captured.
Codimension-3 Bifurcation for Continuous Saddle Bimodal Linear Dynamical Systems
Authors: Ferrer Josep , Peña Marta , Susin Antoni
Published: March 2018

We continue the study of the structural stability and the bifurcations of planar continuous bimodal linear dynamical systems (that is, systems consisting of two linear dynamics acting on each side of a straight line, assuming continuity along the separating line). Here, we complete the study when one of the subsystems is a saddle, leading to a 3D bifurcation diagram where a large catalogue of bifurcations appears: four surfaces of codimension-1 bifurcations; two sequences of surfaces of additional codimension-1 bifurcations; two lines of codimension-2 bifurcations; and one codimension-3 bifurcation.
Constructing Chaotic Systems from a Class of Switching Systems
Authors: Zhang Yuping , Liu Xinzhi , Zhang Huaiyue , Jia Chunhua
Published: March 2018

This paper aims to develop an approach for constructing chaotic systems from a class of linear continuous-time switching systems. First, the Shilnikov criterion is analyzed and extended to the switching systems. Then some kinds of “swing planes” are provided via a heteroclinic loop design, which act as switching planes to chaotify the systems. Furthermore, a numerical example is presented to validate the proposed principle and implementation scheme. The theoretical analysis and numerical simulation have demonstrated the feasibility and effectiveness of the developed techniques.
FUNCTIONAL AND KINEMATIC ANALYSIS OF A WRIST RADIAL HEMIARTHROPLASTY DESIGN
Authors: Hooke Alexander W. , Wagner Eric , Pettersson Kurt , Fischer Per , Rizzo Marco
Published: March 2018

Purpose: A biomechanical functional assessment was performed on a newly designed wrist hemiarthroplasty implant with aimed to identifying differences between the native wrist and wrist following the hemiarthroplasty procedure with [Formula: see text] and without a proximal row carpectomy (Hemi). Methods: Six cadaveric wrists were mounted on a custom testing fixture and underwent a series of functional tests to investigate differences in range of motion, muscles moment arms, and axis of rotation between the intact and post-operative wrists. The tested movements included manually-driven flexion-extension, radial-ulnar deviation, dart throwers motion, and circumduction. Results: The only significant change in range of motion was a decrease in flexion between the intact [Formula: see text] and both the Hemi [Formula: see text] and [Formula: see text] [Formula: see text] conditions. Minor differences in the mean position and variability of the axis of rotation’s piercing point were identified. A statistically significant decrease in the flexion moment arm of the flexor carpi radialis was identified between the intact ([Formula: see text][Formula: see text]mm) and [Formula: see text] ([Formula: see text][Formula: see text]mm) conditions. Statistically significant decreases were also identified in the radial deviation moment arms of the extensor carpi radialis brevis’ between the intact ([Formula: see text][Formula: see text]mm) and [Formula: see text] ([Formula: see text][Formula: see text]mm) conditions and the flexor carpi radialis’ between the intact ([Formula: see text][Formula: see text]mm) and Hemi ([Formula: see text][Formula: see text]mm) conditions as well as in the ulnar deviation moment arm of the extensor carpi ulnaris between the intact ([Formula: see text][Formula: see text]mm) and Hemi ([Formula: see text][Formula: see text]mm) conditions. Conclusions: While some statistically significant functional changes were identified between the native and hemiarthroplasty wrist, the findings suggest that post-operative function is equally acceptable in hemiarthroplasty with and without resection of the proximal carpal row.
REVENUE RECYCLING AND COST EFFECTIVE GHG ABATEMENT: AN EXPLORATORY ANALYSIS USING A GLOBAL MULTI-SECTOR MULTI-REGION CGE MODEL
Authors: ZHU YUNFA , GHOSH MADANMOHAN , LUO DEMING , MACALUSO NICK , RATTRAY JACOB
Published: March 2018

Carbon pricing generates revenues which can be recycled back into the economy in different ways to help mitigate the economic cost of abatement. These include, lump-sum transfers to households; reducing existing distortionary taxes, such as income taxes on labor and capital; investment in technology funds leading to energy/emissions efficiency improvements; and/or infrastructure developments that help expedite the adoption of low or lower carbon-intensive technologies. In this paper, we undertake illustrative simulations to explore how different revenue recycling options influence the overall economic outcome in terms of broad macroeconomic indicators, such as Gross Domestic Product (GDP) or household welfare. Environment and Climate Change Canada’s (ECCC) multi-sector, multi-region Computable General Equilibrium (CGE) model (EC-MSMR) is used to simulate various revenue recycling options. These simulations are undertaken for the U.S. economy. The main findings of the paper are: (i) using carbon revenue for a general income tax reduction or investment subsidy is more advantageous than a lump-sum transfer to U.S. consumers in terms of welfare or GDP; and (ii) using carbon revenue for a sector-based subsidy such as renewable energy is more disadvantageous than a lump-sum transfer to consumers. In terms of accumulated welfare effects, our results indicate that the best carbon revenue recycling option is the investment subsidy or capital income tax reduction in the longer horizon; labor tax reductions yield the best outcome in the shorter horizons.
Eclogites from the Marun-Keu Complex, Polar Urals, Russia: a record of hot subduction and sub-isothermal exhumation
Authors: Liu Y. Y. , Perchuk A. L. , Philippot P.
Published: March 2018

Lenses and boudins of eclogitized and non-metamorphic gabbroic and ultramafic rocks occurring in quartzofeldspathic gneisses and migmatites of the Marun-Keu Complex, Polar Urals, are of central interest for the study of fluid-controlled processes in the subducting continental lithosphere. Petrology and mineral chemistry, combined with multi-equilibrium geothermobarometry and phase-equilibrium modelling, applied to mafic eclogitic rocks show a prograde evolution from
c.
685°C, 1.89 GPa and

a

H

2

O

= 0.6 to
c.
745°C, 2.13 GPa and

a

H

2

O

= 1 followed by near-isothermal decompression down to
c.
1.63 GPa. The absence of pre-eclogitic H
2
O-bearing mineral inclusions in garnet and omphacite suggests that the primary magmatic rocks have not been affected by prograde metamorphism during subduction due to the lack of fluid. We suggest that the Marun-Keu Complex represents a coherent crustal block that experienced the same
P
–
T
evolution but provides a metamorphic record of different
P
–
T
parameters because of an uneven introduction of aqueous-bearing fluids during subduction and exhumation. The tectonometamorphic history of the Marun-Keu Complex is best attributed to the relatively hot regime of the continental margin subduction beneath an island arc, whereas the blueschist-facies part of the complex towards the north could be related to the closure of the Uralian Ocean.
Mean-field limits for multi-hop random-access networks
Authors: Cecchi F. , Van de Ven P.M. , Shneer S.
Published: March 2018

Recent years have seen wireless networks increasing in scale, interconnecting a vast number of devices over large areas. Due to their size these networks rely on distributed algorithms for control, allowing each node to regulate its own activity. A popular such algorithm is Carrier-Sense Multi- Access (CSMA), which is at the core of the well-known 802.11 protocol. Performance analysis of CSMA-based networks has received significant attention in the research literature in recent years, but focused almost exclusively on saturated networks where nodes always have packets available.

However, one of the key features of emerging large-scale networks is their ability to transmit packets across large distances via multiple intermediate nodes (multi-hop). This gives rise to vastly more complex dynamics, and to phenomena not captured by saturated models. Consequently, performance analysis of multi-hop random-access networks remains elusive. Based on the observation that emerging multi-hop networks are typically dense and contain a large number of nodes, we consider the mean-field limit of multihop CSMA networks. We show that the equilibrium point of the resulting initial value problem provides a remarkably accurate approximation for the pre-limit stochastic network in stationarity, even for sparse networks with few nodes. Using these equilibrium points we investigate the performance of linear networks under different back-off rates, which govern how fast each node transmits. We find the back-off rates which provide the best end-to-end throughput and network robustness, and use these insights to determine the optimal back-off rates for general networks. We confirm numerically the resulting performance gains compared to the current practice of assigning all nodes the same back-off rate.
Analyzing Cascading Failures in Power Grids under the AC and DC Power Flow Models
Authors: Cetinay Hale , Soltan Saleh , Kuipers Fernando A. , Zussman Gil , Van Mieghem Piet
Published: March 2018

In this paper, we study cascading failures in power grids under the nonlinear AC and linearized DC power flow models. We numerically compare the evolution of cascades after single line failures under the two flow models in four test networks. The cascade simulations demonstrate that the assumptions underlying the DC model (e.g., ignoring power losses, reactive power flows, and voltage magnitude variations) can lead to inaccurate and overly optimistic cascade predictions. Particularly, in large networks the DC model tends to overestimate the yield (the ratio of the demand supplied at the end of the cascade to the initial demand). Hence, using the DC model for cascade prediction may result in a misrepresentation of the gravity of a cascade.