bluuebunny/crossref_metadata_2025 huggingface dataset:
“Conflict” or “Cooperation”: A Study on The Spontaneous Order of Urban Public Space Development from The Perspective of Stakeholders
Authors: Haoyu Cheng
Published: December 2020

Urban public space nourishes social relations, at the same time, the evolution and development of public space are also influenced by social relations. As an important factor affecting the development of public space, the interest relation of citizens presents the characteristics of conflict or cooperation in the occupation of public spaces and finally presents itself in the space form. Based on the point, this paper attempts to explain the evolution and development of urban public space from the perspective of stakeholders, and on this basis investigates the generation mechanism of spontaneous order in the development of urban public space. To meet the research aims, this paper first clarified the inherent meaning that space reflects and shapes social relations, and then selected a certain urban area of Jinan in northern China for the case study. Through the data collected from Google earth history images, interviews, and published reports, the evolution of the major public spaces in this case from 2003 to 2020 was objectively presented. On this basis, the author analysed the social relations, appeals, and actions of various stakeholder groups (such as local people and non-local traders) in different periods in this case, as well as the staged outcomes of their effects on the public space. Finally, a game model of stakeholders was established. The results indicated that the development of a city is a process that mitigates the conflict between social and public space resources. In the occupation of public space resources, the relationship between the stakeholders is dynamic: when the cost is high and the return is low, the stakeholders show a trend of “conflict”; when costs are low and returns are high, the tendency to “conflict” diminishes.; When costs and benefits reach some kind of equilibrium, “cooperation” tends to rise and gradually leads to spontaneous order. Although this spontaneous order has its limitations due to the limited rationality of its participants, it still can play a positive role in the development of urban public space. In the concluding section, the paper proposes an optimization strategy of interest integration and coordination for urban space development, which may be of reference value for architects and government management to actively guide this spontaneous order in urban planning and urban governance.
Hydraulic Modelling of Riverbed Embankment Under the Hričov Weir
Authors: Pavúček Martin , Rumann Ján , Dušička Peter
Published: December 2020

The weir of the Hričov water structure has an untypical shortened stilling basin, which affects significant scour development in the downstream riverbed. A rockfill embankment structure adjacent to the stilling basin was constructed to prevent the formation of scours in the riverbed. However, increased flows at the weir erode this fortification and it is necessary to replenish the material back to the embankment after the flow situations. A 2D hydraulic model constructed in a flume of the Hydraulic laboratory was used for the research of new downstream fortification, which would be better resist the scouring effects. The model was created according to Froude’s modelling similarity as a 2D model of the weir structure with control gates and part the downstream riverbed consisting of gravel. Different designs of the embankment were not allowed to interfere with the existing construction of the water structure. The construction of the embankment was designed as a concrete “secondary” stilling basin adjacent to the existing one. Tested variants of the embankment were of different length and depth of the stilling basin. The length varied from 11 to 24 m and the depths varied from 0 to 1,8 m. Overall 11 different design of the embankment were investigated. Each design was tested for three different flow rates on the model simulating common and extreme flow situations at the weir. The flows were selected to simulate also different hydraulic phenomena at the weir – overflow, outflow, and free overflow. After each flow simulation the scour in the riverbed was measured. The measured scour parameters were depth of the scour, the distance of the deepest point from the existing water structure and the amount of the material carried away. The resulting parameters were assessed with respect to each other for the corresponding flow rates. The best results in scour reduction were achieved for horizontal embankment with the depth of 0 m. The designs with increased depth were causing secondary hydraulic jump in the riverbed which increased the scours. The tested designs of the embankments were able to reduce scour size by up to 45% for the outflow, by less than 20% for free overflow and by more than 80% at the overflow.
Dynamic Response Analysis of Trapezoidal Basins on Numerical Models
Authors: Özaslan Bilal , Emre Haşal M. , Khanbabazadeh Hadi , Akbaş Merve , İyisan Recep
Published: December 2020

The severity and spatial distribution of ground motion are affected by geological and geotechnical conditions as well as earthquake source properties. The characteristics of ground motion at a particular site depend on many factors such as tectonics of the region, rupture mechanism, source distance, geological formations and local soil conditions and subsurface topography. Thus, the estimation of surface ground motion during earthquakes is a challenging issue in civil engineering. Consequently, the research investigates an answer to the question of how the surface movement would change as a result of combinations of basic wave phenomena in alluvial basins with soil nonlinearity where basin width is comparable to depth. In this study, one and two-dimensional dynamic analyses were performed under different levels of bedrock motion excitation by using idealized symmetrical basin models to research the effects of geotechnical site conditions and bedrock inclination of basin edge for soft site class defined by seismic codes. Geotechnical properties of the soft soil layers in the models were defined as site class E that mostly needed site specific dynamic analysis by classification of NEHRP 2015 provisions. The top layers of basin models are soft cohesive alluvium underlain by stiffer material. In the basin models, the soil layers were assumed to extend horizontally and limited with basin edges having a constant slope. The acceleration time histories and response spectrums were calculated at surface points with equal interval on the top of the basin performing one and two-dimensional dynamic analyses by excitation of 22 strong ground motions. The response spectrum values and amplifications calculated for different sections of the basin from the two and one dimensional (2D and 1D) dynamic analyses. Consequently, the impact factors of the basin effect could be derived depending on location and periods as Sae(T)2D/Sae(T)1D.
Indicator System to Measure the Qualities of Urban Space Affecting Urban Safety and Coexistence
Authors: Gómez de Salazar Nuria Nebot , Martín Marta Cornax , Chamizo Nieto Francisco J. , Rosa-Jiménez Carlos , Muñoz José Becerra
Published: December 2020

Urban space design directly influences its own safety. Sometimes this security is given by urban furniture, lighting or urban facilities, among other aspects. This paper presents a methodology based on the development of a system of indicators that provides the opportunity to assess what qualities of urban space influence street safety. It is important to know what aspects of public space make the citizen consider it a safe place and at the same time, to contrast these data with scientific documents. The first results are shown after applying this methodology to the case study of the city of Malaga, and specifically, to a sample of streets selected based on objective criteria crime rate. For research and obtaining indicators, digital surveys have been carried out on a group of 300 people, using Google Forms and social networks. Likewise, to obtain samples of the streets with the highest and lowest crime rates, registration data has been geolocated by the tolls of the Geographic Information Systems (GIS). The main contribution of this document is focused on defining indicators to characterize and quantify the safety in the streets of the urban public space. These are contrasted with objective data and records of insecurity and crime, and can be applicable to any street in any city. Finally, through these indicators, it is intended to know what are the parameters that influence urban safety for future designs of public spaces, or their renovation, achieving in the future, the existence of streets with a higher level of safety.
Reconstruction of Ancient Stone Arch Bridge Via Terrestrial LiDAR Technology
Authors: Cao Wei , Shi Yufeng , Mei Dong , Li Mingyue , Liu Dehe
Published: December 2020

The ancient stone arch bridge is the cultural and architectural heritage of human, the protection of it is a worldwide problem. Considering the problems that some ancient stone arch bridges with a long history lack reliable design data, and it is difficult to identify their detailed geometric features efficiently, a novel reconstruction method of ancient stone arch bridge via terrestrial LiDAR scans is proposed in this paper. Firstly, the terrestrial LiDAR w applied to get the whole point clouds of the ancient stone arch bridge surface, and then the point clouds was preprocessed. The non-uniform rational B-spline (NURBS) algorithm is used to extract, fit and reconstruct the ancient stone arch bridge based on the point clouds. The results show that terrestrial LiDAR technology could be used to get point clouds of the stone arch bridge comprehensively and accurately, and realize the reconstruction of the stone arch bridge model.
Use of a 3D scanner technology to create an information model of historic buildings - a case study
Authors: Mésároš Peter , Mandičák Tomáš , Čabala Jozef , Kozlovská Mária
Published: December 2020

Digitization in construction has become increasingly important in recent years. Digital technologies are a way to facilitate some activities and thus save time and money on construction projects. Creating an information model of an existing building can be relatively time-consuming. The 3D scanner allows you to perform personal tasks with time savings, which is very important when managing construction projects. Digital technologies are also an effective tool for these activities. This research discusses the issue of 3D scanning of a historical building for real state surveying purposes. In this case study, the subject of the study was the chapel of St. Rosalie in Košice. The aim of the research was to describe the course of digitization in the building in question, i.e. the creation of an information model of the building. At the same time point out the possibilities and limitations of a 3D scanner on this specific construction.
Experimental model of plan curved footbridge supported by arch
Authors: Trenz Jan , Zlatuška Karel , Nečas Radim
Published: December 2020

The new type of plan curved structure with the upper deck has been developed within the research of arch structures. The paper describes the process of the research and the design of the physical model in scale 1:10 built for testing of the structure type. The design of the structure has been based on observation of static and dynamic behaviour of arch structures of various radii of plan curvature. Internal forces, deformations and natural modes were monitored for different methods of the design. At first, a simplified method of designing plan curved structures with arch situated in the bridge axis has been investigated and the behaviour of structures designed in accordance with this method has been studied. It has been discovered that simplified method can be used for design of structures with plan curvature radius of 250 m or higher. After investigation of other design methods, the method based on inversion of suspension cable has been chosen for further development. The method has been improved with processes that allow the application for plan curved structures. The result is a plan curved structure supported by a spatial arch. The geometry of the arch corresponds with ideal thrust line of the arch for given permanent loads. The composite structure with steel arch of span of 60,0 m with radius of plan curvature of 37,5 m has been designed and analysed thoroughly in MIDAS Civil software. The behaviour of the calculation model has been compared with behaviour of physical model in scale 1:10 that has been built in laboratory of the Faculty of Civil Engineering of BUT. Results have demonstrated that calculations and measurements correspond.
Compressive Strength, Splitting Tensile Strength, and Chloride Penetration Resistance of Concrete with Supplementary Cementitious Materials
Authors: Mohamed Osama , Hawat Waddah Al , Najm Omar
Published: December 2020

This article presents the outcomes of a study that examined the durability and mechanical characteristics of self-consolidating concrete (SCC) mix in which a percentage of the required ordinary Portland cement (OPC) was substituted with either fly ash or ground granulated blast furnace slag (GGBS). The first part of the study evaluates the chloride penetration resistance and compressive strength of SCC mixes in which OPC in a designed control mix was partially replaced in a series of mixes by fly ash in percentages ranging from 10% to 40%. It noted that replacing OPC with fly ash at each of the four percentages studies improved chloride resistance of concrete compared to the control mix made of 100% OPC as binder. The 40% fly ash mix was the best performer in terms of resistance to chloride migration in contrast with the 100% OPC mix. Samples prepared using the 40% fly ash mix SCC mixes had the lowest compressive strength after 7 days of moist curing. However, the 28-day compressive strength of 40% fly ash mix was a healthy 55.75 MPa, only slightly lower than the 100% OPC mix. Tests also showed that adding 2% or fewer basalt fibres to the SCC mix in which 40% of OPC improves concrete resistance to chloride migration in contrast with the 40% fly ash mix that didn’t contain basalt fibres. This paper also reports the relationship between splitting tensile strength and compressive strength of SCC mixes in which up to 80% of OPC was substituted with GGBS. A total of eight mixes were produced by varying the amounts of GGBS used to replace the OPC content of the control mix. The fresh properties were assessed through the flow test, visual stability index (VSI), and the T50. An empirical relationship was developed to predict the splitting tensile strength based on 28-day compressive strength, and its accuracy was evaluated in comparison to formulas in various design codes.
Traffic Planning Concerning Pedestrian Traffic in Cities
Authors: Bartuška Ladislav , Hanzl Jiří
Published: December 2020

The aim of the paper is to familiarize readers with the issue of planning and modelling the urban pedestrian traffic. The introduction describes the factors that must be taken into account before designing new pedestrian roads or during reconstructing existing pedestrian areas. The paper furthermore introduces levels of quality of movement of pedestrian traffic, individual types and categories of pedestrians, including their own traffic behaviour. The final part of the paper summarizes the various approaches to addressing this issue, including the presentation of the possibilities of pedestrian traffic modelling based on computer simulation.
Elastic-Plastic Load-Carrying Capacity of Simple Frame Structures
Authors: Juhás Pavol , Šenitková Ingrid Juhásová
Published: December 2020

The efficiency of plasticity for the design of steel frame structures is analysed in the paper. Technical theory of plasticity and standard assumptions and requirements for numerical study are applied. Two types of simple frames (double-sided pinned supporting and fixing) with different loading, geometrical dimensions of the frames and cross-sections of their columns and beams are considered. Some results of the numerical study and conclusions are also presented.
Perceived Air Quality and Productivity in the Office Building
Authors: Šenitková Ingrid Juhásová
Published: December 2020

Problems of perceived quality of the environment find its reason especially when monitoring performance and productivity of work. Thus, verification of the degree of environmental quality impact on employee performance comes into consideration. The results of two independent studies involving 50 subjects, and using similar procedures and blind exposures have shown that increasing the air quality (by decreasing the pollution load or by increasing the ventilation rate, with otherwise constant indoor climate conditions) can improve the performance of simulated office work (text typing, addition and proof-reading). Performance testing was performed in the open space office of an office building at three air exchange intensities: n1 = 0.5 h−1, n2 = 1.5 h−1 and n3 = 2.5 h−1. Other physical environmental parameters that could have affected the assessors’ performance were maintained in the range: indoor air temperature θai = 22 - 24 °C, relative air humidity φai = 40 - 60%, air velocity vai ≤ 0.25 m.s−1, noise level load L = 40 - 50 dB (A), daylight - diffuse radiation component. The present results document the productivity benefits of providing good indoor air quality and indicate that providing indoor air of a higher ventilation level will increase productivity.
Replacement of Polymer Fibers with Hemp Fibers in Concrete
Authors: Machová Petra , Šál Jiří
Published: December 2020

In our experiment, we tried to replace polymer fibers with hemp fibers and verify whether the properties and advantages of polymer fibers in concrete will be retained even with this interchange. Polymer fibers are added to the mixer to produce fresh concrete or mortar, and we did the same in our case. Polymer fibers do not replace conventional structural reinforcement of concrete, but improve some properties, such as suppressing and controlling cracking in concrete, reducing plastic settling and cracking in concrete settling, improving concrete toughness, etc. Cannabis and its cultivation have a long tradition. The growing season lasts about four months and during that time at least 2.5 times more wood mass grows on one hectare than in the same forest area. The plant consists of root, leaves, seeds and stalk, which contains about a quarter of the fiber and the rest is a woody mass, the so-called shives. We used only hemp fiber in concrete. Hemp fiber excels in its strength, durability and natural protection against pests. Sets of beams according to EN 196-6 were produced for the proposed solution. Although the article deals with hempcrete, i.e. concrete, the tests were performed according to the cement testing standard. In total, three blends were produced with different hemp fiber ratios, three strips each. Compressive strength and flexural tensile strength were measured.
Unique, firmest full bricks in Czech Republic
Authors: Fiala Jan , Lapka Miroslav , Mikoláš Milan , Jun Jan Fiala
Published: December 2020

History of ceramic products reach as far as 27000 years back. Discovery of first ceramic products definitely showed ways for first approach in processing plastic materials suitable for production of future ceramic products. When we imagine the method of firing first statuettes, it must have placed the foundations for very first field kilns. Thus if we will push over selves to work harder, fire high-quality bricks and abide technological procedures of production. We will be able to produce unique products which will stay here --with us over centuries.
Specific problems of engineering geological survey of sewer constructions
Authors: Niemiec Dominik , Marschalko Marian , Yilmaz Isik , Sombathy Erik , Yang Shuran , Kubáč Jan , Matuszková Barbara , Duraj Miloš , Mendes Estevao
Published: December 2020

Sewerage constructions, unlike other types of constructions, require a certain specific methodological approach based on the fact that we have to deal primarily with the issue of earthworks related to the extraction of soils. Furthermore, it is necessary to deal with the hydrogeological conditions that affect the implementation of sewerage structures from multiple angles. The presence of water changes, for example, the physical-mechanical parameters of soils. The actual implementation of sewerage structures can change the flow of groundwater in the case of poor implementation of the backfill. All these specifics are pointed out in the presented publication.
Smart Parking System based on Improved OCR Model
Authors: Bassam Rami , Samann Fars
Published: December 2020

Smart parking system becomes essential nowadays specially in urban area because it can reduce the time and the fuel wasted in searching for an empty parking slot. The aim of this paper is to develop smart parking system based on improved Optical Character Recognition (OCR) model. The proposed system consists of three stages: 1) OCR based parking slot detection, 2) User notification based on IoT approach, 3) Smart parking meter based on Simple Mail Transfer Protocol (SMTP). In this system, the vacant parking slots are detected using improved OCR model by labeling the parking slots with specific characters. The system identifies empty parking slots by detecting these characters with installed camera above the parking slots, otherwise the parking slots are occupied. The performance of the proposed OCR model in detecting these characters is enhanced by considering two stages of advanced morphology filter to remove unwanted small/large objects from the image. The accuracy of the proposed OCR model is tested by eight images having different parking street textures as a background and characters written with seven font styles. The idea of detecting empty parking spaces is to share the number of vacancies on a website for the drivers searching for a parking space. However, a time-controlled parking system with different charge rate each hour can be considered to make the best utilization of parking spaces available in urban areas. Therefore, a smart parking meter is proposed to notify the user through Email about the time left that allowed to be parked and the change in charge rate. The proposed system is developed and implemented using vision assistant of LabView.
Using AHP Methods in Maintenance to Improve Reliability and Equipment Performance
Authors: Abed Kadhum A. , Mutlag Sattar A.
Published: December 2020

The engineers are usually expected to consider several influential criteria when selecting as a single best alternative for water maintenance system (WMS). This research discusses the approach based on the Analytic Hierarchy Process (AHP) as a decision making tool for selecting WMS. Supported with information of equipment breakdown, the questionnaire method as well as personal interviews as a main tool to collect data and information in the practical aspect of the study. In this study, the AHP decision support tool was applied in a maintenance systems field in the town of AL-Fallujah Water Treatment Project, Iraq. The AHP was applied to evaluate and an alternative is chosen from a set of maintenance alternatives: [ Preventive Maintenance (M1), Proactive Maintenance (M2), Total Productive Maintenance (M3), Predictive maintenance (M4) and Corrective Maintenance (M5)] vs eight of Maintenance pillars. Results indicate the advantages over traditional Decision Making selection methods. By using this information with AHP the best rank of alternatives was M3(11.85), M4(9.67) and so on. Moreover, the relationship between M3 and the pillars of maintenance: indicates a very high correlation 78%. The study reached a number of conclusions, the most important of which is the existing of a very strong impact for the proposed maintenance system in improving the performance and reliability of FWTP project operations.
Evaluation of Al-Kufa City Road Networks Using GIS
Authors: Abdlabass Ahmed Yahya , Al-Jameel Hamid Athab
Published: December 2020

One of the important points to develop any region is the suitable road network and understanding the relationship between land use and transportation system. To effectively develop any network, there is an urgent need to obtain proper connectivity and orientation. However, Al-Kufa road network has received significantly limited attention and studies to evaluate this network. Therefore, this study has focused on analyzing the present road network connectivity in Al-Kufa city. Furthermore, the GIS program has been adopted in this study to represent the main features in the city. Several measures have been adopted in this study to perform the evaluation for the road network such as beta index, gamma index, alpha index, spreading index, correlation index, etc. The main objective of this study is to assess how the road network is successful to containment the present road traffic and suggestions for future traffic movement performance to accommodate the growth. The results demonstrate that urgent improvements are required such as adding new roads. Finally, the network density could give better another important prediction of the road network measures.
The Nano Fluid Effect on the Plethora of Thermal Efficiency in Evacuated Tube Solar Collector
Authors: Sultan Khalid F. , Anead Hosham S. , Jabber Sura Abdul
Published: December 2020

Nano fluids are the most attractive means to boost heat transfer system efficiency, since they have high thermal conductivity. This research aims to investigate the effects of utilizing Nano fluids (Cu (30 nm) + DW) as the working fluid on the thermal effectiveness of the evacuated solar collector. Experiments for statistical analysis of techniques were Performed using nanoparticles in three volume concentrations (1%, 3% and 5% vol.), solar collector’s thermal efficiency was tested at various volume flow rates (30, 60 and 90 Lit / min). This research indicated that percentages improvement of (Cu (30nm) + DW) with working fluid (distilled water) at 5 % volume concentration and different volume flow rates are (15.326%, 16.96% and 19.98% ) while these percentages of improvement when used only distilled water at the same volume concentration and various volume flow rates are ( 2.41%, 4.36%, 5.43%), The high thermal conductivity of the working fluids could enhance solar collector efficiency compared to that of the distilled water. The area under the curve (the thermal efficiency curve) was used as indicator to assess the results of the volume flow rate and nanoparticle concentrations on total collector efficiency. Nano fluids (Cu + DW), at concentrations ratio (1, and 5%vol) and volume flow rates (30, and 90 L/min), Values of thermal solar characteristic value of (FR (τα), – FRUL) are 0.407, 1.156 W/m2.k, 0.522 and 0.945 W/m2.k, Whereas for distilled water at volume flow rates 30 L/min and 90 Lit/min are 0.252, 0.945 W/m2.k, 0.321 and 1.051 W/m2.k respectively, where FR (τα), – FRUL are two parameters used to describe how collector works, where FR (τα) is an indication of how energy absorb and FRUL is an indication of energy is lost, the two parameters are constitute the simplest practical collector model, the values indicates that the solar collector efficiency when using Nano fluids (Cu(30)+ DW) is higher than efficiency when using distilled water due to high thermal conductivity for copper. The type of Nano fluid is a key factor for heat transfer enhancement, and improve performance of evacuated tube solar collector.
Air Distribution Performance Inside Office Room with Combined Displacement and Personal Ventilation
Authors: Mahdi Ala’a Abbas , Al-amir Qusay Rasheed , Yakoob Asmaa Khudhair
Published: December 2020

The main goal of the paper is to study the effect of adding a new type of ventilation device, which is personal ventilation to displacement ventilation, and know its effect on heat removal and how to reach thermal comfort for humans. Experiments were practically conducted inside a thermally insulated room with full-scale of dimensions (3 ϗ 1.75 ϗ 3) m. The results of the experimental work are used to validate the CFD simulations. The RNG k-e model is utilized to simulate the cases for predicting indoor airflows. The displacement ventilation supply temperature is close to 18°C and the flow velocity of 0.25 m/s. As for the personal ventilation, the flow rates 5l/s and 10l/s were taken with a temperature close to where the air was drawn (at height 0.4 m). It was concluded that adding personal ventilation improved air quality and thermal comfort, and it was also concluded that a flow rate of 10 l/s gave better efficiency for the device to function in terms of air distribution performance index and effectiveness of temperature (e.t) which about 71% and 1.8 respectively.
Manta Ray Foraging Optimization for Hyper-Parameter Selection in Convolutional Neural Network
Authors: Kamil Omar Adil , Al-Shammari Shaymaa W.
Published: December 2020

Convolutional neural networks (CNNs) have been attracting attention as one of the most common deep learning techniques used for different applications like images classifications, objects recognition, face recognition, etc. The performance and efficiency of the CNN model depend directly on their hyper-parameter, which must be selected by an expert or using one of the models that proposed and improved. This makes it very important to determine the optimal hyper-parameters. In this work, the Manta Ray Foraging Optimization (MRFO) algorithm is used to select CNN’s Hyper-Parameter. We demonstrate that MRFO efficiently explores the solution space. This allowing CNN with simple architecture to achieve a good classification accuracy over Cifar_10 dataset. In the presented experiment Cifar_10 dataset used as the benchmark data sets. By optimizing CNN hyper-parameters with MRFO algorithm and comparing the obtained results with other CNN, it was approved that the accuracy was improved.
Evolution of microstructure and properties of Cu-4.5 wt.% Ag alloy prepared by vacuum horizontal continuous casting in solid solution and aging treatment
Authors: Tang Linsheng , Xie Weibin , Xiao Xiangpeng , Chen Huiming , Wang Hang , Yang Bin
Published: December 2020

The vacuum horizontal continuous casting method was used for preparing Cu-4.5 wt.% Ag alloy rod containing few oxygen. The evolution of microstructure was observed by metallographic microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM). The results showed that the hardness and electrical conductivity of Cu-4.5 wt.% Ag alloy aged at 450 °C for 12 h were increased by 60 HV and 12 %IACS than solution treated alloy. TEM observation showed that the continuous precipitates of Ag are uniformly distributed in matrix with the form of particles and strips. Through calculation, the strength increment of peak aged Cu-4.5 wt.%Ag alloy from solid solution hardening and precipitation hardening are 86 MPa and 136 MPa, respectively.
Acylindrical hyperbolicity and existential closedness
Authors: André Simon
Published: December 2020

Let

G
G

be a finitely presented group, and let

H
H

be a subgroup of

G
G

. We prove that if

H
H

is acylindrically hyperbolic and existentially closed in

G
G

, then

G
G

is acylindrically hyperbolic. As a corollary, any finitely presented group which is existentially equivalent to the mapping class group of a surface of finite type, to

O
u
t

(

F
n

)

\mathrm {Out}(F_n)

or

A
u
t

(

F
n

)

\mathrm {Aut}(F_n)

for

n
≥
2

n\geq 2

or to the Higman group, is acylindrically hyperbolic.
Unitary equivalence of complex symmetric contractions with finite defect
Authors: Gu Caixing
Published: December 2020

A criterion for a contraction

T
T

on a Hilbert space to be complex symmetric is given in terms of the operator-valued characteristic function

Θ

T

\Theta _{T}

of

T
T

in 2007 (see Nicolas Chevrot, Emmanuel Fricain, and Dan Timotin [Proc. Amer. Math. Soc. 135 (2007), pp. 2877–2886]). To further classify unitary equivalent complex symmetric contractions, we notice a simple condition of when

Θ

T

1

\Theta _{T_{1}}

and

Θ

T

2

\Theta _{T_{2}}

coincide for two complex symmetric contractions

T

1

T_{1}

and

T

2

.

T_{2}.

As an application, surprisingly we solve the problem for any defect index

n
n

, when the defect indexes of contractions are

2
,

2,

this problem was left open by Nicolas Chevrot, Emmanuel Fricain, and Dan Timotin [Proc. Amer. Math. Soc. 135 (2007), pp. 2877–2886]. Furthermore, a construction of

3
×
3

3\times 3

symmetric inner matrices is proposed, which extends some results on

2
×
2

2\times 2

inner matrices (see Stephan Ramon Garcia [J. Operator Theory 54 (2005), pp. 239–250]) and

2
×
2

2\times 2

symmetric inner matrices (see Nicolas Chevrot, Emmanuel Fricain, and Dan Timotin [Proc. Amer. Math. Soc. 135 (2007), pp. 2877–2886]).
A one-dimensional symmetry result for entire solutions to the Fisher-KPP equation
Authors: Sourdis Christos
Published: December 2020

We consider the Fisher-KPP reaction-diffusion equation in the whole space. We prove that if a solution has, to main order and for all times (positive and negative), the same exponential decay as a planar traveling wave with speed larger than the minimal one at its leading edge, then it has to coincide with the aforementioned traveling wave.
Invariant subspaces for Fréchet spaces without continuous norm
Authors: Menet Quentin
Published: December 2020

Let

(
X
,
(

p
j

)
)

(X,(p_j))

be a Fréchet space with a Schauder basis and without continuous norm, where

(

p
j

)

(p_j)

is an increasing sequence of seminorms inducing the topology of

X
X

. We show that

X
X

satisfies the Invariant Subspace Property if and only if there exists

j
0

≥
1

j_0\ge 1

such that

ker
⁡

p

j
+
1

\ker p_{j+1}

is of finite codimension in

ker
⁡

p

j

\ker p_{j}

for every

j
≥

j
0

j\ge j_0

.
From Picard groups of hyperelliptic curves to class groups of quadratic fields
Authors: Gillibert Jean
Published: December 2020

Let

C
C

be a hyperelliptic curve defined over

Q

\mathbb {Q}

, whose Weierstrass points are defined over extensions of

Q

\mathbb {Q}

of degree at most three, and at least one of them is rational. Generalizing a result of R. Soleng (in the case of elliptic curves), we prove that any line bundle of degree

0
0

on

C
C

which is not torsion can be specialised into ideal classes of imaginary quadratic fields whose order can be made arbitrarily large. This gives a positive answer, for such curves, to a question by Agboola and Pappas.
Linear independence of cables in the knot concordance group
Authors: Davis Christopher , Park JungHwan , Ray Arunima
Published: December 2020

We produce infinite families of knots

{

K
i

}

i
≥
1

\{K^i\}_{i\ge 1}

for which the set of cables

{

K

p
,
1

i

}

i
,
p
≥
1

\{K^i_{p,1}\}_{i,p\ge 1}

is linearly independent in the knot concordance group,

C

\mathcal {C}

. We arrange that these examples lie arbitrarily deep in the solvable and bipolar filtrations of 

C

\mathcal {C}

, denoted by

{

F

n

}

\{\mathcal {F}_n\}

and

{

B

n

}

\{\mathcal {B}_n\}

respectively. As a consequence, this result cannot be reached by any combination of algebraic concordance invariants, Casson-Gordon invariants, and Heegaard-Floer invariants such as

τ
\tau

,

ε
\varepsilon

, and

Υ
\Upsilon

. We give two applications of this result. First, for any

n
≥
0

n\ge 0

, there exists an infinite family

{

K
i

}

i
≥
1

\{K^i\}_{i\geq 1}

such that for each fixed

i
i

,

{

K

2
j

,
1

i

}

j
≥
0

\{K^i_{2^j,1}\}_{j\geq 0}

is a basis for an infinite rank summand of

F

n

\mathcal {F}_n

and

{

K

p
,
1

i

}

i
,
p
≥
1

\{K^i_{p,1}\}_{i, p\geq 1}

is linearly independent in

F

n

/

F

n
.5

\mathcal {F}_{n}/\mathcal {F}_{n.5}

. Second, for any

n
≥
1

n\ge 1

, we give filtered counterexamples to Kauffman’s conjecture on slice knots by constructing smoothly slice knots with genus one Seifert surfaces where one derivative curve has nontrivial Arf invariant and the other is nontrivial in both

F

n

/

F

n
.5

\mathcal {F}_n/\mathcal {F}_{n.5}

and

B

n
−
1

/

B

n
+
1

\mathcal {B}_{n-1}/\mathcal {B}_{n+1}

. We also give examples of smoothly slice knots with genus one Seifert surfaces such that one derivative has nontrivial Arf invariant and the other is topologically slice but not smoothly slice.
Individual Differences in the Relationship Between Pain Fear, Avoidance, and Pain Severity in a Chronic Abdominal Pain Sample and the Moderating Effect of Child Age
Authors: Cushing Christopher C , Kichline Tiffany , Friesen Craig , Schurman Jennifer V
Published: December 2020

Background/Purpose

Most studies examining the components of the fear-avoidance model have examined processes at the group level. The current study used ecological momentary assessments to: (a) investigate the group and intraindividual relationships between pain fear, avoidance, and pain severity, (b) identify any heterogeneity between these relationships, and (c) explore the role of moderators to explain such heterogeneity.

Methods

Seventy-one pediatric patients with chronic abdominal pain (M = 13.34 years, standard deviation = 2.67 years) reported pain fear, avoidance, and pain severity four times per day over 14 days.

Results

Results indicated significant individual differences in the relationship between pain fear and pain avoidance predicting pain severity. Child age helped explain the heterogeneity in the relationships between pain avoidance and pain severity such that older children had a stronger and more positive relationship between these variables. The random effect between pain fear and pain severity also indicated a moderator trend of child age such that older children were likely to have a stronger and more positive relationship.

Conclusions

The present study extends the fear-avoidance model by highlighting the importance of identifying potential individual differences when examining pain fear, avoidance, and pain severity. Furthermore, the current study suggests that child development should be considered in the model. However, future randomized control designs are necessary to explore the causal relationships between pain fear and avoidance on pain severity and potential developmental differences.
Theory-based Behavioral Predictors of Self-reported Use of Face Coverings in Public Settings during the COVID-19 Pandemic in the United States
Authors: Barile John P , Guerin Rebecca J , Fisher Kiva A , Tian Lin H , Okun Andrea H , Vanden Esschert Kayla L , Jeffers Alexiss , Gurbaxani Brian M , Thompson William W , Prue Christine E
Published: December 2020

Background

Investigating antecedents of behaviors, such as wearing face coverings, is critical for developing strategies to prevent SARS-CoV-2 transmission.

Purpose

The purpose of this study was to determine associations between theory-based behavioral predictors of intention to wear a face covering and actual wearing of a face covering in public.

Methods

Data from a cross-sectional panel survey of U.S. adults conducted in May and June 2020 (N = 1,004) were used to test a theory-based behavioral path model. We (a) examined predictors of intention to wear a face covering, (b) reported use of cloth face coverings, and (c) reported use of other face masks (e.g., a surgical mask or N95 respirator) in public.

Results

We found that being female, perceived importance of others wanting the respondent to wear a face covering, confidence to wear a face covering, and perceived importance of personal face covering use was positively associated with intention to wear a face covering in public. Intention to wear a face covering was positively associated with self-reported wearing of a cloth face covering if other people were observed wearing cloth face coverings in public at least “rarely” (aOR = 1.43), with stronger associations if they reported “sometimes” (aOR = 1.83), “often” (aOR = 2.32), or “always” (aOR = 2.96). For other types of face masks, a positive association between intention and behavior was only present when observing others wearing face masks “often” (aOR = 1.25) or “always” (aOR = 1.48).

Conclusions

Intention to wear face coverings and observing other people wearing them are important behavioral predictors of adherence to the CDC recommendation to wear face coverings in public.
Trends in prevalence and outcomes of frailty in a Swiss university hospital: a retrospective observational study
Authors: Bonjour Thierry , Waeber Gérard , Marques-Vidal Pedro
Published: December 2020

Background

Frailty complicates management and worsens outcomes. We assessed the prevalence, determinants and consequences of frailty among elderly patients in a hospital setting.

Design

Retrospective observational study in a Swiss university hospital.

Methods

22,323 patients aged ≥65 years hospitalized between January 2009 and December 2017 at the internal medicine ward were included. Frailty was defined by the Hospital Frailty Risk Score (HFRS) and patients were categorized as low (HFRS<5), intermediate (HFRS 5–15) and high (HFRS>15) risk.

Results

Overall prevalence of intermediate and high risk of frailty was 43% and 20%, respectively; prevalence was higher in women and increased with age. Prevalence of high risk of frailty increased from 11.4% in 2009 to 31% in 2012, and decreased to 19.2% in 2017. After multivariable adjustment, frailty was associated with increased length of stay: average and (95% confidence interval) 11.9 (11.7–12.1), 15.6 (15.4–15.8) and 19.7 (19.3–20.1) days for low, intermediate and high risk, respectively, and increased likelihood of ICU stay: odds ratio (OR) and (95% CI) 1.57 (1.41–1.75) and 2.10 (1.82–2.42) for intermediate and high risk, respectively, p for trend <0.001. Frailty was associated with increased likelihood of hospital costs >70,000 CHF: OR and (95% CI) 3.46 (2.79–4.29) and 10.7 (8.47–13.6) for intermediate and high risk, respectively, p for trend <0.001, and with a lower likelihood of complete cost coverage: OR and (95% CI) 0.70 (0.65–0.76) and 0.52 (0.47–0.58) for intermediate and high risk, respectively, p for trend<0.001.

Conclusions

Frailty is a frequent condition among hospitalized patients and is associated with higher costs.
Adolescent Marijuana Use in the United States and Structural Breaks: An Age-Period-Cohort Analysis, 1991–2018
Authors: Gu Jiaxin , Guo Xin , Veenstra Gerry , Zhu Yushu , Fu Qiang
Published: December 2020

To investigate temporal patterns, sociodemographic gradients, and structural breaks in adolescent marijuana use in the United States from 1991 to 2018, we used hierarchical age-period-cohort logistic regression models to distinguish temporal effects of marijuana use among 8th, 10th, and 12th graders from 28 waves of the Monitoring the Future survey (1991–2018). Structural breaks in period effects were further detected via a dynamic-programing–based method. Net of other effects, we found a clear age-related increase in the probability of marijuana use (10.46%, 23.17%, and 31.19% for 8th, 10th, and 12th graders, respectively). Period effects showed a substantial increase over time (from 16.23% in 2006 to 26.38% in 2018), while cohort effects remained stable throughout the study period. Risk of adolescent marijuana use varied by sex, racial group, family status, and parental education. Significant structural breaks during 1995–1996, 2006–2008, and 2011–2013 were identified in different subpopulations. A steady increase in marijuana use among adolescents during the latter years of this time period was identified. Adolescents who were male, were non-Black, lived in nonintact families, and had less educated parents were especially at risk of marijuana usage. Trends in adolescent marijuana use changed significantly during times of economic crisis.
Associations Between Workplace Factors and Depression and Anxiety in Australian Heavy Vehicle Truck Drivers
Authors: Chalmers Taryn , Maharaj Shamona , Lal Sara
Published: December 2020

Introduction

A number of health issues have been identified as prevalent within the Australian heavy vehicle driving population. Mental illnesses, such as depression and anxiety, are among those disorders that have been regularly reported, however, the contributing factors are yet to be elucidated.

Methods

This study aimed to assess the associations between workplace factors such as years of employment, social interaction and shift length, with depressive and anxious symptomology in a cohort of 60 Australian heavy vehicle drivers.

Results

Significant positive associations were identified between depression and alcohol use (P = 0.044), coffee consumption (P = 0.037), number of accidents during career (P = < 0.004), and number of hours driving per shift (P ≤ 0.001). Anxiety was found to be positively associated with a number of hours driving per week (P ≤ 0.001), and the number of accidents or near misses during a driving career (P = 0.039).

Conclusion

Several workplace factors were identified as being correlated to depression or anxiety within this cohort, suggesting potential changes to rostering systems and education regarding alcohol use may benefit the mental health of this driver population.
Fat Grafting and Auto-Augmentation Mastopexy After Breast Implant Removal: Technique and Evaluation of Outcomes Using BREAST-Q
Authors: Papadopoulos Sarantos , Colpaert Steven D M , Goulis Dimitrios G , Nigdelis Meletios P , Grimbizis Grigorios F , Tio Joke , Abdallah Abdallah and
Published: December 2020

Background

Auto-augmentation mastopexy after implant removal has been described as a possible alternative for women who do not opt for implant replacement and decline major reconstructive surgery.

Objectives

This study aimed to evaluate patient satisfaction after auto-augmentation mastopexy relative to the final breast volume and to assess the role of fat grafting on patients’ satisfaction and quality of life according to the BREAST-Q questionnaire.

Methods

Forty-seven breasts from 28 patients who underwent implant removal and auto-augmentation mastopexy were reviewed; 9 patients (group 1) were primarily treated with several fat grafting sessions with subsequent auto-augmentation, 5 (group 2) were treated primarily with auto-augmentation, but subsequently expressed a wish for breast augmentation by lipofilling, and 14 patients (group 3, control) had only auto-augmentation.

Results

Group 1 patients maintained their breast volume, and showed significant improvements in breast satisfaction, psychosocial well-being, and contentment with breast surgery outcomes (P = 0.01, ˂0.01, and ˂0.01, respectively). However, the physical well-being of this group, as well as response to final cup size or interaction parameters, did not improve (P = 0.06). In group 2, all except 1 patient had breast volume reduction to A cup, as was the case with one-third of the patients in control group 3 (group 3A, n = 5) who scored lower, and thus were less satisfied with the breast auto-augmentation than group 3B, who achieved final bigger cup sizes (P ˂ 0.01).

Conclusions

Auto-augmentation mastopexy resulted in substantial improvements in the parameters measured by BREAST-Q. Thus, combined auto-augmentation mastopexy and lipofilling provided a better alternative treatment after breast implant removal.

Level of Evidence: 4