bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biomechanical design analysis and experiments evaluation of a passive knee-assisting exoskeleton for weight-climbing
Authors: Li Bo , Yuan Bo , Tang Shuai , Mao Yuwen , Zhang Dongmei , Huang Changyun , Tan Bilian 
Published: August 2018

Purpose
This paper aims to investigate weight-climbing assistance strategy for the biomechanical design of passive knee-assisting exoskeleton (PKAExo) and evaluate a designed PKAExo which stores energy when the knee joint flexes and releases the energy to assist ascending when the knee joint extends.

Design/methodology/approach
The authors constructed theoretic modeling of human weight-climbing to analyze characteristics of knee angle and moment. They then conducted camera-based movement analysis, muscle strength and endurance tests and surface electromyography (sEMG) measures to verify the relationship of knee angle and moment with both stair height and load weight. Afterwards, the authors proposed an assistant strategy for passive knee assistance, then gave out designed PKAExo and conducted mechanical experiment to test the knee-assisting torque. Finally, the authors conducted comparison experiment based on measuring the sEMG signals of knee extensor to verify the assistance effect of the PKAExo for weight-climbing.

Findings
The knee extensor produces the maximum force during weight-climbing, and the muscle force provided by knee extensor has significant increasing rate along with the stair height. Thus, the assistance torque of PKAExo is designed to increase nonlinearly along with increasing knee angle. It stores energy when knee flexes and assists when knee extends. Both the mechanical experiment and comparison experiment have demonstrated that the PKAExo is able to provide nonlinear assistance torque for weight-climbing, thus decreasing the average maximum load of knee extensor by about 21 per cent, reducing muscle fatigue and enhancing wearer’s weight-climbing ability.

Originality/value
The authors construct theoretic maximum force model produced by knee extensor for weight-climbing in static situation and conduct a series of experiments to verify and revise the model, which is the fundamental reference for knee-assisting mechanism designed for weight-climbing. The authors have also provided and validated an assistant strategy and the mechanism based on the biomechanical analysis, which aims to translate wearer’s energy-providing mode form high load to mid-low load by storing energy when knee flexes and assisting when knee extends. The PKAExo decreases the maximum load of knee extensor, reduces muscle fatigue and helps people to easily climb with load.
Does “clean” pay off? Housing markets and their perception of heating technology
Authors: Hahn Jonas , Hirsch Jens , Bienert Sven 
Published: August 2018

Purpose
The purpose of this paper is to investigate the role of distinct types of heating technology and their price impact in German residential real estate markets, considering a wide range of other housing market determinants. The authors aim to test and to verify specifically, whether the obsolescence of heating technology leads to a significant price discount and whether higher technological standards (and environmental friendliness) come with a price premium on the market.

Design/methodology/approach
The authors create housing market models for rental and sales segments by constructing generalized additive models with explicit multi-layered spatial components. To elaborate a profound and contemporary answer using these models, the authors perform large-sample regression analyses based on more than 400,000 observations covering German residential properties in 2015.

Findings
First and foremost, the heating system indeed shows significant explanatory importance for measuring housing rents and purchasing price. Second, the authors find that it makes a difference whether clean “green” technologies are implemented or whether “brown” systems with obsolete technology or fossil energy sources is on hand. Ultimately, the authors conclude that while low energy consumption indeed comes with a price premium, this needs to be interpreted together with the property’s heating type, as housing markets seem to outweigh the “green premium” by “brown discounts” if low energy consumption figures are powered by a certain type of heating technology system.

Research limitations/implications
Aside of a possible omitted variable bias, the main research limitation is constituted by the integration of asking prices in the analysis, as actual transaction prices are not systematically transparent on national level in Germany. Limitations are discussed at the end of the paper.

Practical implications
This work supports investors who face the challenge of making environmental- and energy-related decisions as well as appraisers who deliver financial fundamentals for such. Third, the paper supports both asset managers as well as investment strategists in argumentation pro-environmental investments beyond all ecological necessity.

Social implications
This paper contributes to the current discussion on climate change and the eclectic role of real estate in this context. The authors deliver evidence on pricing effects as a measure of socioeconomic acceptance of progressive heating technology and environmental friendliness as an imperative of twenty-first century societies.

Originality/value
This is the first study on “green premiums” or “brown discounts” that includes heating technology as a potential and distinct driver of value and rents. It is a contemporary contribution and delivers original information on the quantitative impact of contemporary and anachronistic technology in heating to researchers as well as investors and appraisers.
Identification of crocin, crocetin and zeaxanthin in Crocus sativus grown under controlled environment in Malaysia
Authors: Anuar Nordiyanah , Taha Rosna Mat , Mahmad Noraini , Othman Rashidi 
Published: August 2018

Purpose
The purpose of the study is to identify the high valuable compounds which are crocin, crocetin and zeaxanthin in the stigmas and stamens of Crocus sativus grown under controlled environment in Malaysia.

Design/methodology/approach
Spectrophotometry and high-performance liquid chromatography (HPLC) analysis were used to identify and measure crocin, crocetin and zeaxanthin content qualitatively and quantitatively in the stigmas and stamens of C. sativus grown under controlled environment in Malaysia.

Findings
The results of this study showed that crocin, crocetin and zeaxanthin were detected in the stigmas. However, among those three compounds, only crocetin was detected in the stamens. In the stigmas, the detectable level of crocin was high compared to crocetin and zeaxanthin. It was also found that crocetin was higher in the stamens compared to in the stigmas.

Originality/value
This is the first attempt in Malaysia that the stigmas and stamens were directly purified from the natural sources by means of no addition of preservatives as C. sativus has never been grown here before. Furthermore, limited reports are available regarding the identification of compounds in saffron stamens.
How events in emergency medicine impact doctors’ psychological well-being
Authors: Howard Laura , Wibberley Christopher , Crowe Liz , Body Richard 
Published: August 2018

BackgroundEmergency medicine is a high-pressured specialty with exposure to disturbing events and risk. We conducted a qualitative study to identify which clinical events resulted in emotional disruption and the impact of these events on the well-being of physicians working in an ED.MethodsWe used the principles of naturalistic inquiry to conduct narrative interviews with physicians working in the ED at Central Manchester University Hospitals NHS Foundation Trust, between September and October 2016. Participants were asked, ‘Could you tell me about a time when an event at work has continued to play on your mind after the shift in which it occurred was over?’ Data were analysed using framework analysis. The study had three a priori themes reported here. Other emergent themes were analysed separately.ResultsWe interviewed 17 participants. Within the first a priori theme (‘clinical events’) factors associated with emotional disruption included young or traumatic deaths, patients or situations that physicians could relate to, witnessing the impact of death on relatives, the burden of responsibility (including medical error) and conflict in the workplace. Under theme 2 (psychological and physical effects), participants reported substantial upset leading to substance misuse, sleep disruption and neglecting their own physical needs through preoccupation with caring. Within theme 3 (impact on relationships), many interviewees described becoming withdrawn from personal relationships following clinical events, while others described feeling isolated because friends and family were non-medical.ConclusionsClinical events encountered in the ED can affect a physician’s psychological and physical well-being. For many participants these effects were negative and long lasting.
Inter- and intraobserver reliability for angiographic leptomeningeal collateral flow assessment by the American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR) scale
Authors: Ben Hassen Wagih , Malley Claire , Boulouis Grégoire , Clarençon Frédéric , Bartolini Bruno , Bourcier Romain , Rodriguez Régent Christine , Bricout Nicolas , Labeyrie Marc Antoine , Gentric Jean Christophe , Rouchaud Aymeric , Soize Sébastien , Saleme Suzana , Raoult Hélène , Gallas Sophie , Eugène François , Anxionnat René , Herbreteau Denis , Bracard Serge , Naggara Olivier 
Published: August 2018

BackgroundThe adequacy of leptomeningeal collateral flow has a pivotal role in determining clinical outcome in acute ischemic stroke. The American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR) collateral score is among the most commonly used scales for measuring this flow. It is based on the extent and rate of retrograde collateral flow to the impaired territory on angiography.ObjectiveTo evaluate inter- and intraobserver agreementin angiographic leptomeningeal collateral flow assessment.Materials and methodsThirty pretreatment angiogram video loops (frontal and lateral view), chosen from the randomized controlled trial THRombectomie des Artères CErebrales (THRACE), were sent for grading in an electronic file. 19 readers participated, including eight who had access to a training set before the first grading. 13 readers made a double evaluation, 3 months apart.ResultsOverall agreement among the 19 observers was poor (κ = 0,16 ± 6,5.10-3), and not improved with prior training (κ = 0,14 ± 0,016). Grade 4 showed the poorest interobserver agreement (κ=0.18±0.002) while grades 0 and 1 were associated with the best results (κ=0.52±0.001 and κ=0.43±0.004, respectively). Interobserver agreement increased (κ = 0,27± 0,014) when a dichotomized score, ‘poor collaterals’ (score of 0, 1 or 2) versus ‘good collaterals’ (score of 3 or 4) was used. The intraobserver agreements varied between slight (κ=0.18±0.13) and substantial (κ=0.74±0.1), and were slightly improved with the dichotomized score (from κ=0.19±0.2 to κ=0.79±0.11).ConclusionInter- and intraobserver agreement of collateral circulation grading using the ASITN/SIR score was poor, raising concerns about comparisons among publications. A simplified dichotomized judgment may be a more reproducible assessment when images are rated by the same observer(s) in randomized trials.
PMI’s own in vivo clinical data on biomarkers of potential harm in Americans show that IQOS is not detectably different from conventional cigarettes
Authors: Glantz Stanton A 
Published: August 2018

IntroductionNew ‘heated tobacco products’ are being marketed in several countries with claims that they expose users to lower levels of toxins than conventional cigarettes which could be read as being less likely to cause health problems than conventional cigarettes. In the USA, Philip Morris International (PMI) has submitted an application to the Food and Drug Administration for permission to market its heated tobacco product, IQOS, with reduced exposure and reduced risk claims.MethodsAnalysis of detailed results on 24 biomarkers of potential harm in PMI studies of humans using IQOS compared with humans using conventional cigarettes.ResultsAmong American adults, there is no statistically detectable difference between IQOS and conventional cigarette users for 23 of the 24 biomarkers of potential harm in PMI’s studies. In Japan, there were no significant differences between people using IQOS and conventional cigarettes in 10 of 13 biomarkers of potential harm. It is likely that some of the significant differences are false positives.ConclusionDespite delivering lower levels of some toxins than conventional cigarettes, PMI’s own data fail to show consistently lower risks of harm in humans using its heated tobacco product, IQOS, than conventional cigarettes.
On the topological complexity of aspherical spaces
Authors: Farber Michael , Mescher Stephan 
Published: August 2018

The well-known theorem of Eilenberg and Ganea [Ann. Math. 65 (1957) 517–518] expresses the Lusternik–Schnirelmann category of an Eilenberg–MacLane space [Formula: see text] as the cohomological dimension of the group [Formula: see text]. In this paper, we study a similar problem of determining algebraically the topological complexity of the Eilenberg–MacLane spaces [Formula: see text]. One of our main results states that in the case when the group [Formula: see text] is hyperbolic in the sense of Gromov, the topological complexity [Formula: see text] either equals or is by one larger than the cohomological dimension of [Formula: see text]. We approach the problem by studying essential cohomology classes, i.e. classes which can be obtained from the powers of the canonical class (as defined by Costa and Farber) via coefficient homomorphisms. We describe a spectral sequence which allows to specify a full set of obstructions for a cohomology class to be essential. In the case of a hyperbolic group, we establish a vanishing property of this spectral sequence which leads to the main result.
Bounding execution resources for the task scheduling problem in cyber-physical systems
Authors: Rădulescu Vlad , Andrei Ştefan , Cheng Albert M. K. 
Published: August 2018

In designing and analyzing real-time systems, the central problem resides in finding a feasible schedule for a given task set, if one exists. A lot of research effort has been carried out in approaching the various aspects of task scheduling. While most results have been achieved for preemptive scheduling, the non-preemptive case has still room for improvement, due to its complexity. In addition, the widespread usage of cyber-physical systems (CPS) is putting real-time scheduling in the position to deal with new challenges, as additional (and sometimes particular) requirements are raised by such systems.
This paper, which continues the previous work of the authors, introduces a new lower bound on the number of processing units that allows a feasible schedule of a task set for both preemptive and non-preemptive scheduling. As a specific CPS issue, the necessity of moving the processing units in space, which incurs additional time requirements, is considered. The single-instance case is first discussed, then the results are extended to the periodic case.
The Production of Clouds Containing Supercooled Water Droplets or Ice Crystals Under Laboratory Conditions
Authors: Schaefer Vincent J. 
Published: August 2018

The basic laboratory experiment in which a supercooled cloud may be seeded and converted to ice crystals is described in considerable detail. Such information is given as type and preparation of the cold chamber, light sources which are effective for different purposes, methods to follow in forming supercooled clouds, and procedures to follow in seeding them.
The transition temperature at which ice crystals form spontaneously is given as − 39°C ± 0.1°C as the result of a recent study. A simple replica technique for preserving the exact structure of the crystals in plastic is described.
On the Prognostic Usefulness of the Correlation Between Pressure and Temperature Changes at 3 km.
Authors: Hess Seymour L. , Wagner Harold 
Published: August 2018

The correlation between pressure and temperature changes at 3 km is computed for six stations in the United States in order to test the forecasting rule that a one degree centigrade temperature change is associated with a one mb pressure change of the same sign at that level. The highest correlations are found with 12 hour changes, but these appear to be due to parallel diurnal variations of pressure and temperature. Positive correlations are found for 24 hour changes but they are so low that little prognostic assistance can be expected from so imperfect a relationship.
Consideration of the indicated horizontal temperature advection and of the station position in a pattern of troughs and ridges is found not to materially improve the performance of the relationship.
Effects of Topography and Other Factors on the Movement of Lows in the Middle East and Sudan
Authors: El-Fandy M. G. 
Published: August 2018

In the area extending from the Middle East to the southern Sudan the pressure distribution generally assumes typical seasonal patterns. Apart from winter (December to February) the main low-pressure system which has a direct control on the weather of the area under consideration is an oscillatory barometric minimum, which during the two transitional seasons (spring—March to May—and autumn—September to November) is centered over the central Sudan, and is referred to as the Sudan monsoon low. In October, which represents average conditions in autumn, for example, this low normally extends to about lat. 16°N, but continues towards north with a small inverted V-shaped arm projecting to the northern Red Sea. As winter starts the low acquires a southerly displacement and by January, which represents average conditions in winter, it becomes situated near the Abyssinian Lake Plateau. On the other hand in late spring and early summer the low moves from the central Sudan across Arabia to Persia, and by July it becomes a part of the Asiatic monsoon low which extends to the N.E. Sudan.
The movements of the Sudan low take place in the form of a series of oscillations the average track of which has two outstanding features, namely: (1) There is a remarkable tendency for the low to be located near tablelands. A similar feature is also observed with secondary depressions travelling over the E. Mediterranean in winter. (2) Outstanding northward oscillations of the low take place when middle-latitudes travelling depressions invade the E. Mediterranean from West.
It has also been observed that air currents, not necessarily obeying pressure-gradient, flow along the general run of the Abyssinian Plateau as a result of convergence into the Sudan low, and along the general run of the Persian Plateau (the Valley of Iraq) as a result of convergence into active depressions near Cyprus in winter. Such air currents have been referred to as “effective currents.”
The writer suggests that the image principle may enter into the explanation of these features. The theory which determines the type of motion produced when fluid is drawn off from the center of a revolving disc of incompressible fluid is made use of; but further mathematical treatment and dynamical considerations have been carried out, assuming the active oscillatory low as a slowly travelling cylinder whose axis represents a two-dimensional sink.
Slope and Valley Winds in the Columbia River Valley *
Authors: Cross C. M. 
Published: August 2018

The behavior of slope and valley winds near the town of Trail in the Columbia River valley system in southern British Columbia was studied, and the results compared with those obtained from similar studies made in the Alps. The hourly wind velocities for two stations—one in the main valley, the other in a side valley—were resolved into components parallel to and at right angles to the valley. This procedure gives the valley and slope winds respectively.
The usual diurnal wind pattern was found to prevail in most instances, with up-slope and up-valley winds during the day, and down-slope and down-valley winds at night. These systems were much better developed during the summer than in winter, and approximated the ideal pattern more closely on sunny days when the overall pressure gradient was weak.
The Role of Meteorology in Projects of the Corps of Engineers in the Missouri River Basin *
Authors: McClendon Elmo W. 
Published: August 2018

The comprehensive plan for the development of water resources of the Missouri River Basin provides for flood control, navigation, electric power generation, irrigation, and other miscellaneous water uses. Of these features the Corps of Engineers is primarily responsible for flood control and for river and harbor developments in the interest of navigation. In the planning, construction, and operation of water control projects to fulfill these primary responsibilities, meteorology plays a very definite and important role.
Meteorology as an art touches the lives of all—as an applied science it affects the plans and actions of numerous organizations which are vitally concerned with the predictability of weather, its variation and extremes. The latter is particularly true in the Corps of Engineers in which weather is one of the basic factors to be considered in the planning, construction, and operation of river development projects.
The Relation Between the Tropopause and Convective Activity in the Subtropics (Puerto Rico)
Authors: Graves Maurice E. 
Published: August 2018

The temperature field from 9 km to 19 km at San Juan is studied by means of measuring the slopes of 12-hourly sounding curves and drawing tropopause and temperature anomaly patterns on time scales. Two distinct tropopause types are found and these are termed primary and secondary tropopauses.
A rainfall index is computed as a measure of convective activity and it is compared with changes in tropopause pressure and temperature. The secondary tropopause sinks to a minimum elevation with large rainfall maxima.
500-Millibar Studies at Project AROWA
Authors: Berry F. A. , Haggard W. H. , Wolff Paul M. 
Published: August 2018

In support of several related applied meteorological research tasks at Project AROWA, studies are being made of pressure patterns at the 500-mb level. Preliminary results of investigations based on data from the period 1946 through 1951 are presented.
Examples of studies of the geostrophic wind profile, daily twenty-four-hour height-change charts, and tracks of the height-change centers are presented. A discussion of the preparation of composite charts for various types of blocking patterns is included. Some comments are made on the development of normal height charts, and the historical map program.
Clear-Air Turbulence Near the Jet-Stream Maxima *
Authors: Clem Leroy H. 
Published: August 2018

The development of turbo-jet aircraft has made high-level clear air turbulence a major problem for aviation interests. This paper emphasizes the association of the majority of this turbulence with the pronounced vertical wind shear in and near the maximum wind speed centers that move along the jet stream.
A physical model is proposed as a possible explanation of clear air turbulence, the associated cirrus bands and wind streaks in the jet maxima. This model is supported by an analogy drawn with similar low-level phenomena studied by Woodcock and others. The model can explain distribution of these features in the horizontal by means of helical vortices which are dependent upon proper vertical wind shear and stability conditions. The observed multiple layers in the vertical are also explained by this model.
It is believed that the reason why most of the clear-air turbulence is found near the jet-stream maxima is simply because the necessary shear and stability conditions associated with this turbulence are most frequently fulfilled in that region.