bluuebunny/crossref_metadata_2025 huggingface dataset:
Proposed Base-Station Location Optimization with Genetic Algorithm Scheme for Lte Network Radio Planning
Authors: Jaafar Shahad Nafea , Hamza Kadum Ekhlas , Al-Salihi Viean Abdulmuhsin
Published: March 2021

Long-term evolution (LTE) is used widely in inefficient network technologies which serve billions of users. These technologies have the following features like higher bandwidth, high spectrum efficiency and less latency. This paper proposes minimizing the cost of a cellular network, which usually includes the optimum selection and base-station locations that meet certain capacity and coverage constraints. In the LTE wireless network framework, coverage and capacity planning are interrelated in terms of interference. Moreover, the ever-increasing capacity demand for non-uniformly distributed users makes base station location optimization an important action. This paper adopts one type of improvement, which is a genetic algorithm-based methodology that optimally performs the task of base-stations location by minimizing the cost of the network while fulfilling the coverage and capacity criteria planning by using ATDI ICS TELECOM. Reducing 19.95% of the overlap of the area will result in good coverage of the proposed GA thus, improving efficiency of the network.
Development and Manufacturing of Flexible Lightweight Walker for Fractured Foot
Authors: Khazaal Ali S , Aziz Sadiq J , Shandookh Ahmed A
Published: March 2021

This study includes two main parts. The first part encompasses the manufacturing process; we made two types of AFO’s modified static AFO and adjustable hinge AFO. The materials used in manufacturing are polypropylene and steel. Fabrication is done using a vacuum molding technique. An ankle orthosis test for a patient who suffers from ankle fracture caused by a sports injury. The second part of the research involves testing with dynamic gait analysis on the treadmill and F-Socket. Besides, the analysis of the AFO’s models is illustrated to determine the fatigue safety factor and the analysis of the Von-Mises stress. Also, the results of the gait cycle (GRF, Pressure distribution, Center of Pressure (COP), Candace, Stride length, and footprint analysis) used to show the significant difference between the pathological subjects and normal person who are wearing ankle-foot orthoses (AFO’s) compare with a normal subject (healthy person). Measuring the interference (pressure and force) between the legs with AFO’s area of contact for all subjects then using this data for analysis of the mathematical models by used ANSYS V.15 software. Where it shows that the highest stress concentration in the ankle joint region, where the stress reached 418.9 MPa, the safety factor is 2.4 in adjustable hinge AFO, and for modified static AFO (192.8 MPa), the safety factor (0.447). On the other side, a questionnaire was conducted for a certain number of patients to find the difference between the manufactured models, to know the acceptance by the patient for AFO’s.
Investigation of Mechanical Properties for Unsaturated Polyester-Based Fibre Glass Composites Filled by Recycled Milled Composites
Authors: Abd-Ali Nabel Kadum , Madeh Ahmed Raee
Published: March 2021

The present study discusses the mechanical properties of a composite material consisting of polyester resin reinforced by random mat glass fiber and milled of (scraped material) waste of glass-reinforced pipe (GRP). The current work uses the finite element method based on ANSYS program as a tool for evaluating the performance of the design proposal for the car roof. The milled wasted glass fiber composite has showed a good and acceptable young modulus, maximum stress, and yield strength compared with the random mat composite. The agreement of the suggested material comes from the experimental and theoretical results for some of the laboratory tests. The divergence between results of random mat glass fiber and milled waste glass fiber do not exceed the percentages errors that are obtained during experimental work, which are 3.98% and 5.26% for tensile strength and strain until failure in the tensile test, 4.5% and 3.6% for flexural strength and strain in bending test and 12.32% and 1.27% for strain energy and deformation in the impact test, respectively. The result of the numerical solution was compatible with the experimental results. The result extracted from this study proved that the milled of waste of glass fiber composite is an acceptable reinforcement material with economic and environmental benefits.
The Effect of Laser Energy on the Rate of Corrosion for Ni46-Ti50-Cu4 Shape Memory Alloy
Authors: Abbas Abeer R , Hubeatir Kadhim A , Resan Kadhim K
Published: March 2021

The microstructure, mechanical and corrosion properties of Nickel-Titanium-Copper shape memory alloy were inspected in this research. The Ni46-Ti50-Cu4alloy was prepared based on the powder metallurgy method, then mixed and cold-pressed at (600, 700, and 800) MPa, respectively, to form cylindrical samples of 11mm diameter × 16.5mm length. After pressing, the samples got sufficient green strength for handling. The specimens were consequently sintered at (850,900 and 950) °C for five hours in an electric vacuum tube furnace. The optimum compacting pressure and sintering temperature were identified using the Minitab program. The effect of optimum parameters on the shape memory was 83.5 % at a temperature of sintering of 850°C and a pressure of compacting 800 MPa. Samples prepared under the optimum process conditions were then irradiated utilizing a pulsed ND: YAG laser at 300mJ, 400mJ, 500mJ, and 600mJ. Multiple tests were conducted on the alloys, including shape memory effect, porosity measurements, scanning electron microscopy (SEM), and corrosion rate test. The results indicated that decrease the corrosion rate after laser processing. The lowest value of the rate of corrosion was obtained when the energy of laser irradiation was 500, which corresponds to the structural and physical properties.
Improving Mechanical and Morphological Characteristics Pva/Sio2Nanocomposites for Food Packing Applications
Authors: Sabr Ohood Hmaizah , Hussein Asra Ali , Obaid Massar Najim
Published: March 2021

This study deals with using nano-SiO2to enhance the characteristics of PVA for food packing applications. Thin-film of Polyvinyl alcohol (PVA)/nano-silica (nano-SiO2) was prepared by adding different weights of silica (0, 5, 7, 9) wt. %. Differential scanning calorimetry, atomic force microscopy (AFM), FTIR, and mechanical properties such as tensile strength, modulus, elongation at break, and micro-hardness used to examine the characteristics of PVA/nano-SiO2films. The results revealed a dramatic improvement in the PVA/nano-SiO2mechanical properties, increasing nano-SiO2content to 7 wt %, the value of tensile strength increasing from 62 MPa to 143 MPa. While increasing SiO2content to 9 wt.%, the tensile strength decreased to 65 MPa. The study also showed that the value of elongation at break and modulus of elasticity of film increment with increases in the nano-SiO2content. There was also an increase in the crystallinity from 0.97 (for pure PVA) to 1.154 at 7wt. % nano-SiO2. Crystallinity, however, decreased to 0.012 with the increase of SiO2to 9 wt. %. FTIR results revealed that there was physical interaction between nano-SiO2and PVA. AFM result showed less roughness at 7wt. % from nano-SiO2. Generally, the results showed that the concentration of 7% of the nano –SiO2in thin films resulted in a significant improvement in the mechanical properties of the films. These findings suggest that nano-SiO2can be useful as food packaging material to maintain food quality.
Developing of PMMA Bone Cement Performance by Modified TiO2NPs
Authors: Al-Janabi S K , Al-Maamori M H , Braihi A J
Published: March 2021

Polymethylmethacrylate is considered the most prevalent bone cement base material. Most fractures that occur during function are due to its weakness and lack of mechanical strength. The apparent limitations of PMMA are insufficient ductility, strength, and viscoelastic behavior. The current study aims to strengthen and improve PMMA bone cement properties by adding modified TiO2nanoparticles (m-TiO2NPs). Therefore, the silane coupling agent modified the neat TiO2NPs and then added different ratios (0.5, 1, 1.5, and 2 wt %) to the PMMA bone cement. Fourier transform infrared spectroscopy (FTIR) technique used to investigate the modification process and specify the bonding type between m-TiO2NPs and the PMMA bone cement matrix. The SEM technique is used to study the morphologies of the prepared samples. Properties such as tensile strength, compression strength, modulus of elasticity, and impact strength, were measured. Results proved the successes of TiO2NPs modification by silane coupling agent and the absence of any chemical bonding between this modified filler and other PMMA bone cement ingredients. The mechanical properties increased by m-TiO2NPs addition up to 1 wt% ratio then decreased. The morphology results supported the mechanical properties trends.
Numerical and Experimental Study of Elastic Recovery in Deep Drawing of Low Carbon and Galvanized Steel Sheet Conical Products
Authors: Jabbar Mohammed S , Jweeg Muhsin J , mohammed Adnan I
Published: March 2021

Deep Drawing is an important sheet metal forming process. It has numerous applications in different industrial fields. Due to improvements in technological techniques, modern industries focused on products dimensional accuracy especially for the products that have inclined walls since it may suffer from the effect of elastic recovery or what is known as springback. Springback is considered a major defect besides thinning, earing, and other deep drawing defects. It may cause serious deviation from demand dimensions particularly for the products inclined by certain angle such as conical shells or products. This study investigates the effect of wall inclination angle, punch velocity, type and thickness of the sheet material on elastic recovery behaviour. Two types of sheet metal, low carbon (AISI 1008) and galvanized steel sheets, of 110 mm diameters circular blanks at 0.9 and 1.2 mm thickness are formed by tooling set (punch, die, and blank holder). Conical dies were used to execute the experimental work and numerical having inclination angles at 70°, 72°, and 74° where, the punch velocity was 100, 150, and 200 mm/min. Numerical simulation was conducted using ABAQUS 6.14 where dynamic explicit solver was used to preform formation of conical products and static or standard solver to predict the behaviour of springback effect. A comparison between the experimental and numerical simulation was conducted. The results show that elastic recovery decreased with increasing of die wall angle, punch velocity, and sheet or blank thickness while increased with increasing of metal yielding stress. The springback factor rose by 0.003 to 0.007 with die angle increasing by 0.002 to 0.006 with punch velocity and thickness increasing, while it decreased by 0.001 to 0.003 with increasing of yielding point. The numerical simulation results show same tendency and high agreement with experimental results with a maximum discrepancy of 4%.
Optimization of Friction Stir Welded Aluminium Plates by the New Modified Particle Swarm Optimization
Authors: Hussien Rasha M , Al-Shammari Mohsin Abdullah
Published: March 2021

Friction stir welding (FSW) is a complex process that needs and trial to reach the optimal properties. In This work deals theoretical consideration done by two ways; first way is conventional Particle Swarm Optimization (PSO) and the second method is new modified Particle Swarm Optimization. The Friction stir welding data were taken from recent studies. The input to the program are nine experiments for different cases and the output is the ultimate stress for each experiment. The artificial neural network is used to relate the relation between input and output to form a cost function. The results show that the modified PSO gives the more accurate optimum result than conventional PSO when compared with other researches with maximum discrepancy 23.5%.
The Effects of Chemical Oxidation on Corrosion Behavior of Ni-Ti Alloy
Authors: Dawood Nawal Mohammed , Ali Enass L
Published: March 2021

Nickel Titanium intermetallic (NiTi) has been used in several fields (mostly corrosion issues were not a concern) since it was discovered about sixteen years ago. In the last decade, alloys made from NiTi have been widely used in the internal and external biomedical tools and equipment such as nails, fixation plates, bone fracture, self-expanding cardiovascular and urological stents, and orthodontic wires. The effects of chemical oxidation on corrosion behavior of Nickel-Titanium shape memory alloy have been investigated in this study. Technique of powder metallurgy was used to prepare the alloy from the elemental powders of Titanium and Nickel with 600 MPa of compacting pressure. The sintering process was achieved in a 10−4 torr vacuum atmosphere at 950 °C . XRD analysis exhibited that Ni and Ti were fully transformed into NiTi (both monoclinic and cubic phase) and Ni3Ti phase. After sintering, the samples are grinded and polished, then samples were surface modified by chemical oxidation. Optical microscopy, scanning and x-ray diffraction techniques were utilized for characterizing the surface samples. The corrosion rate has been studied in vitro by using polarization curves technique in NaF solution at different concentration (0.5, 1,1.5, 2) wt,%. Results of corrosion test indicated that the corrosion current density after chemical oxidation decreased from 0.303 for bare sample to 0.074 in 0.5% NaF solution, which indicates that TiO2 layer on the NiTi SMA surface are protective after chemical oxidation.
An Investigation of Tensile and Thermal Properties of Epoxy Polymer Modified by Activated Carbon Particle
Authors: Hunain Mustafa Baqir , Alnomani Salah N , Razzaq Qabas
Published: March 2021

In this work, the effects of adding activated carbon (AC) powder with epoxy resin were investigated experimentally. The particulate epoxy composites are manufactured in vacuum technique with different weight fraction ratios of AC (0, 5, 10, 15, 20, 25, 30, 35 and 40) % wt. The particle size was measured during this work by laser particle size analyzer with an average size of about (14.74μm). The interaction between epoxy material and AC powder was examined by using Fourier Transform Infrared (FTIR) spectroscopy analysis. Moreover, the glass transition temperature (Tg) of the pure epoxy and composite material were measured by Differential Scanning Calorimeter (DSC). The tensile strength behavior and interaction strength between the matrix material and powder were investigated by conducting tensile test and SEM analysis. The results of FTIR test reveal that there is no a new peak after reinforcing epoxy with AC powder, which proves there is a strong interaction between epoxy resin and AC powder. The DSC results show that the increases by adding AC to epoxy will increase Tg temperature. The findings of FTIR analysis were supported by SEM analysis, which shows a good interaction and strong interfacial between matrix and particles. The tensile strength values increased with increasing AC content up to 15 % wt. with a max value of 26.34 MPa (19.16%), then it decreased to 18.15 MPa at 40 % wt.
Numerical Investigation of Mechanical Behavior for Lattice Structure with Effect of Different Nanomaterial Types
Authors: Aljaberi Mohammed Hussein Kadhim , Al-Baghdadi Maher AR Sadiq , Al-Waily Muhannad , Mohammadi-Aghdam M , Goudarzi Taha
Published: March 2021

Porous biomaterials have extensively been used as new materials for various bio-implants, particularly for bone and bone interfacing components. In practice, while open-cell/permeable porous materials are used to allow osseointegration in bone implants, they should be mechanically durable and stable for the long term to tolerate human weight together with possible static and dynamic loads on the body. It has been ingrained that porous biomaterials can be made considering defined representative volume elements (RVE) by recent growths in additive manufacturing. In this study, two porous biomaterial models, including unit cell and also lattice structure, are presented. The models applied the finite volume method to discretize and solve by using a multi-physics COMSOL mechanical structure code. The cell is modelled using three materials: titanium alloy Ti_6Al-4V-ELI, and in this study, for the first time, two types of nanomaterials: calcined alpha-alumina (α_ Al2O3) and Glass-infiltrated alumina ceramic. The results obtained from this study revealed that for both unit cell and lattice structure, the minimum displacement occurred with Glass-infiltrated alumina ceramic and increased with calcined alumina (α_ Al2O3) and titanium. Moreover, it could be concluded that the maximum stress occurred with the Glass-infiltrated alumina ceramic and decreased with calcined alumina (α- Al2O3) and titanium for the lattice structure.
GO supported Fe doped Ni(OH)2 hexagonal nanosheets for hydrogen evolution reaction in neutral electrolytes
Authors: Hu Junping , Liu Youxing
Published: March 2021

Exploiting non-noble metals catalysts with excellent performance for hydrogen evolution reaction (HER) has aroused gigantic interest, but still challenges. Herein, we reported the graphene oxide (GO) supported Fe doped Ni(OH)2 hexagonal nanosheets (GO-Fe,Ni HHNs) for HER firstly. SEM and XRD were carried out to investigate the morphology and crystal structure of the GO-Fe,Ni HHNs systematically. The elements and bonding of the sample were measured via using XPS. In addition, we found that the recrystallization treatment could significantly improve the morphology and crystallinity of the nanosheets. Most important, the GO-Fe,Ni HHNs possessed exceptional catalytic performance and stability in PBS solution. The overpotential (10 mA cm−2) and Tafel slope were 190 mV and 110 mV dec−1, respectively, significantly better than that of other non-noble metal catalysts reported before.
Asymptotic 𝐾-soliton-like solutions of the Zakharov-Kuznetsov type equations
Authors: Valet Frédéric
Published: March 2021

We study here the Zakharov-Kuznetsov equation in dimension

2
2

,

3
3

and

4
4

and the modified Zakharov-Kuznetsov equation in dimension

2
2

. Those equations admit solitons, characterized by their velocity and their shift. Given the parameters of

K
K

solitons

R
k

R^k

(with distinct velocities), we prove the existence and uniqueness of a multi-soliton

u
u

such that
\[
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="double-vertical-bar u left-parenthesis t right-parenthesis minus sigma-summation Underscript k equals 1 Overscript upper K Endscripts upper R Superscript k Baseline left-parenthesis t right-parenthesis double-vertical-bar Subscript upper H Sub Superscript 1 Subscript Baseline right-arrow 0 as t right-arrow plus normal infinity period">

‖
u
(
t
)
−

∑

k
=
1

K

R
k

(
t
)

‖

H
1

→
0

as

t
→
+
∞
.

\| u(t) - \sum _{k=1}^K R^k(t) \|_{H^1} \to 0 \quad \text {as} \quad t \to +\infty .

\]
The convergence takes place in

H
s

H^s

with an exponential rate for all

s
≥
0

s \ge 0

. The construction is made by successive approximations of the multi-soliton. We use classical arguments to control of

H
1

H^1

-norms of the errors (inspired by Martel [Amer. J. Math. 127 (2005), pp. 1103–1140]), and introduce a new ingredient for the control of the

H
s

H^s

-norm in dimension

d
≥
2

d\geq 2

, by a technique close to monotonicity.
How biases in sperm storage relate to sperm use during oviposition in female yellow dung flies
Authors: Demont Marco , Ward Paul I , Blanckenhorn Wolf U , Lüpold Stefan , Martin Oliver Y , Bussière Luc F
Published: March 2021

Precise mechanisms underlying sperm storage and utilization are largely unknown, and data directly linking stored sperm to paternity remain scarce. We used competitive microsatellite PCR to study the effects of female morphology, copula duration and oviposition on the proportion of stored sperm provided by the second of two copulating males (S2) in Scathophaga stercoraria (Diptera: Scathophagidae), the classic model for sperm competition studies. We genotyped all offspring from potentially mixed-paternity clutches to establish the relationship between a second male’s stored sperm (S2) and paternity success (P2). We found consistent skew in sperm storage across the three female spermathecae, with relatively more second-male sperm stored in the singlet spermatheca than in the doublet spermathecae. S2 generally decreased with increasing spermathecal size, consistent with either heightened first-male storage in larger spermathecae, or less efficient sperm displacement in them. Additionally, copula duration and several two-way interactions influenced S2, highlighting the complexity of postcopulatory processes and sperm storage. Importantly, S2 and P2 were strongly correlated. Manipulation of the timing of oviposition strongly influenced observed sperm-storage patterns, with higher S2 when females laid no eggs before being sacrificed than when they oviposited between copulations, an observation consistent with adaptive plasticity in insemination. Our results identified multiple factors influencing sperm storage, nevertheless suggesting that the proportion of stored sperm is strongly linked to paternity (i.e., a fair raffle). Even more detailed data in this vein are needed to evaluate the general importance of sperm competition relative to cryptic female choice in postcopulatory sexual selection.
Choice of assemblers has a critical impact on de novo assembly of SARS-CoV-2 genome and characterizing variants
Authors: Islam Rashedul , Raju Rajan Saha , Tasnim Nazia , Shihab Istiak Hossain , Bhuiyan Maruf Ahmed , Araf Yusha , Islam Tofazzal
Published: March 2021

Background

Coronavirus Disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a global pandemic following its initial emergence in China. SARS-CoV-2 has a positive-sense single-stranded RNA virus genome of around 30Kb. Using next-generation sequencing technologies, a large number of SARS-CoV-2 genomes are being sequenced at an unprecedented rate and being deposited in public repositories. For the de novo assembly of the SARS-CoV-2 genomes, a myriad of assemblers is being used, although their impact on the assembly quality has not been characterized for this virus. In this study, we aim to understand the variabilities on assembly qualities due to the choice of the assemblers.

Results

We performed 6648 de novo assemblies of 416 SARS-CoV-2 samples using eight different assemblers with different k-mer lengths. We used Illumina paired-end sequencing reads and compared the assembly quality of those assemblers. We showed that the choice of assembler plays a significant role in reconstructing the SARS-CoV-2 genome. Two metagenomic assemblers, e.g. MEGAHIT and metaSPAdes, performed better compared with others in most of the assembly quality metrics including, recovery of a larger fraction of the genome, constructing larger contigs and higher N50, NA50 values, etc. We showed that at least 09% (259/2873) of the variants present in the assemblies between MEGAHIT and metaSPAdes are unique to one of the assembly methods.

Conclusion

Our analyses indicate the critical role of assembly methods for assembling SARS-CoV-2 genome using short reads and their impact on variant characterization. This study could help guide future studies to determine the best-suited assembler for the de novo assembly of virus genomes.
Sentencing Multiple- Versus Single-Offence Cases: Does More Crime Mean Less Punishment?
Authors: Dhami Mandeep K
Published: March 2021

The ‘totality principle’ in law aims to show mercy to offenders in multiple-offence (MO) cases and retain ordinal proportionality in punishing those who commit different categories of offence. The effect of this principle in practice, however, is largely unknown. The present study involved an analysis of data released by the Sentencing Council for England and Wales to estimate the prevalence of MO cases and compare the penalties they received against comparable single-offence (SO) cases. MO cases represented approximately half of the cases in the sample which included violent, property, drugs and driving offences. Offence-specific regression analyses revealed that MO/SO case status was not a significant predictor of receiving a custodial sentence or of custody length. Thus, by applying the totality principle, sentencers may be letting MO offenders ‘off lightly’. Potential explanations for this unintentional effect on decision-making lies in how the totality principle is defined and interpreted, and recommendations are made for revising the guideline on application of the totality principle.
Brain beats heart: a cross-cultural reflection
Authors: Brandt Thomas , Huppert Doreen
Published: March 2021

From the Egyptian Book of the Dead to the doctrine of the Greek philosopher Aristotle, ancient secular and religious cultures throughout the world often considered the heart — and not the brain — to be the home of the emotions, cognition and even the soul. Brandt and Huppert reflect on the reasons behind this belief.
Regional brain iron and gene expression provide insights into neurodegeneration in Parkinson’s disease
Authors: Thomas George E C , Zarkali Angeliki , Ryten Mina , Shmueli Karin , Gil-Martinez Ana Luisa , Leyland Louise-Ann , McColgan Peter , Acosta-Cabronero Julio , Lees Andrew J , Weil Rimona S
Published: March 2021

The mechanisms responsible for the selective vulnerability of specific neuronal populations in Parkinson’s disease are poorly understood. Oxidative stress secondary to brain iron accumulation is one postulated mechanism. We measured iron deposition in 180 cortical regions of 96 patients with Parkinson’s disease and 35 control subjects using quantitative susceptibility mapping. We estimated the expression of 15 745 genes in the same regions using transcriptomic data from the Allen Human Brain Atlas. Using partial least squares regression, we then identified the profile of gene transcription in the healthy brain that underlies increased cortical iron in patients with Parkinson’s disease relative to controls. Applying gene ontological tools, we investigated the biological processes and cell types associated with this transcriptomic profile and identified the sets of genes with spatial expression profiles in control brains that correlated significantly with the spatial pattern of cortical iron deposition in Parkinson’s disease. Gene ontological analyses revealed that these genes were enriched for biological processes relating to heavy metal detoxification, synaptic function and nervous system development and were predominantly expressed in astrocytes and glutamatergic neurons. Furthermore, we demonstrated that the genes differentially expressed in Parkinson’s disease are associated with the pattern of cortical expression identified in this study. Our findings provide mechanistic insights into regional selective vulnerabilities in Parkinson’s disease, particularly the processes involving iron accumulation.
The Role of Ultrasensitive Molecular Methods for Detecting Malaria—The Broader Perspective
Authors: Kamaliddin Claire , Sutherland Colin J , Houze Sandrine , Cottrell Gilles , Briand Valerie , Castaneda Mogollon Daniel , Pillai Dylan R
Published: March 2021

Ultrasensitive molecular diagnostics are lowering the limit of detection for malaria parasites in the blood and providing insights not captured by conventional tools such as microscopy and rapid antigen tests. Low-level malaria infections identified by molecular tools may influence clinical outcomes, transmission events, and elimination efforts. While many ultrasensitive molecular methods require well-equipped laboratories, technologies such as loop-mediated isothermal amplification and recombinase polymerase amplification provide more portable and analytically sensitive solutions. These tools may benefit asymptomatic patient screening, antenatal care, and elimination campaigns. We review the recent evidence, offer our perspective on the impact of these new tests, and identify future research priorities.
Effects of National Adoption of Treat-All Guidelines on Pre-Antiretroviral Therapy (ART) CD4 Testing and Viral Load Monitoring After ART initiation: A Regression Discontinuity Analysis
Authors: Brazier Ellen , Tymejczyk Olga , Zaniewski Elizabeth , Egger Matthias , Wools-Kaloustian Kara , Yiannoutsos Constantin T , Jaquet Antoine , Althoff Keri N , Lee Jennifer S , Caro-Vega Yanink , Luz Paula M , Tanuma Junko , Niyongabo Théodore , Nash Denis
Published: March 2021

Background

The World Health Organization’s Treat-All guidance recommends CD4 testing before initiating antiretroviral therapy (ART), and routine viral load (VL) monitoring (over CD4 monitoring) for patients on ART.

Methods

We used regression discontinuity analyses to estimate changes in CD4 testing and VL monitoring among 547 837 ART-naive patients enrolling in human immunodeficiency virus (HIV) care during 2006–2018 at 225 clinics in 26 countries where Treat-All policies were adopted. We examined CD4 testing within 12 months before and VL monitoring 6 months after ART initiation among adults (≥20 years), adolescents (10–19 years), and children (0–9 years) in low/lower-middle-income countries (L/LMICs) and high/upper-middle-income countries (H/UMICs).

Results

Treat-All adoption led to an immediate decrease in pre-ART CD4 testing among adults in L/LMICs, from 57.0% to 48.1% (−8.9 percentage points [pp]; 95% CI: −11.0, −6.8), and a small increase in H/UMICs, from 90.1% to 91.7% (+1.6pp; 95% CI: 0.2, 3.0), with no changes among adolescents or children; decreases in pre-ART CD4 testing accelerated after Treat-All adoption in L/LMICs. In L/LMICs, VL monitoring after ART initiation was low among all patients in L/LMICs before Treat-All; while there was no immediate change at Treat-All adoption, VL monitoring trends significantly increased afterwards. VL monitoring increased among adults immediately after Treat-All adoption, from 58.2% to 61.1% (+2.9pp; 95% CI: 0.5, 5.4), with no significant changes among adolescents/children.

Conclusions

While on-ART VL monitoring has improved in L/LMICs, Treat-All adoption has accelerated and disparately worsened suboptimal pre-ART CD4 monitoring, which may compromise care outcomes for individuals with advanced HIV.
Coronavirus Disease 2019–Associated Pulmonary Aspergillosis in Mechanically Ventilated Patients
Authors: Permpalung Nitipong , Chiang Teresa Po-Yu , Massie Allan B , Zhang Sean X , Avery Robin K , Nematollahi Saman , Ostrander Darin , Segev Dorry L , Marr Kieren A
Published: March 2021

Background

Coronavirus disease 2019 (COVID-19)–associated pulmonary aspergillosis (CAPA) occurs in critically ill patients with COVID-19. Risks and outcomes remain poorly understood.

Methods

A retrospective cohort study of mechanically ventilated adult patients with COVID-19 admitted to 5 Johns Hopkins hospitals was conducted between March and August 2020. CAPA was defined using composite clinical criteria. Fine and Gray competing risks regression was used to analyze clinical outcomes and, multilevel mixed-effects ordinal logistic regression was used to compare longitudinal disease severity scores.

Results

In the cohort of 396 people, 39 met criteria for CAPA. Patients with CAPA were more likely than those without CAPA to have underlying pulmonary vascular disease (41% vs 21.6%, respectively; P = .01), liver disease (35.9% vs 18.2%; P = .02), coagulopathy (51.3% vs 33.1%; P = .03), solid tumors (25.6% vs 10.9%; P = .02), multiple myeloma (5.1% vs 0.3%; P = .03), and corticosteroid exposure during the index admission (66.7% vs 42.6%; P = .005), and had lower body mass indexes (median, 26.6 vs 29.9 [calculated as weight in kilograms divided by height in meters squared]; P = .04). Patients with CAPA had worse outcomes, as measured by ordinal severity of disease scores, requiring longer time to improvement (adjusted odds ratio, 1.081.091.1; P < .001), and advancing in severity almost twice as quickly (subhazard ratio, 1.31.82.5; P < .001). They were intubated twice as long as those without CAPA (subhazard ratio, 0.40.50.6; P < .001) and had longer hospital stays (median [interquartile range], 41.1 [20.5–72.4) vs 18.5 [10.7–31.8] days; P < .001).

Conclusion

CAPA is associated with poor outcomes. Attention to preventive measures (screening and/or prophylaxis) is warranted in people with high risk of CAPA.
Relative risk of arterial and venous thromboembolism in persons with cancer vs. persons without cancer—a nationwide analysis
Authors: Grilz Ella , Posch Florian , Nopp Stephan , Königsbrügge Oliver , Lang Irene M , Klimek Peter , Thurner Stefan , Pabinger Ingrid , Ay Cihan
Published: March 2021

Aims

An interrelation between cancer and thrombosis is known, but population-based studies on the risk of both arterial thromboembolism (ATE) and venous thromboembolism (VTE) have not been performed.

Methods and results

International Classification of Disease 10th Revision (ICD-10) diagnosis codes of all publicly insured persons in Austria (0–90 years) were extracted from the Austrian Association of Social Security Providers dataset covering the years 2006–07 (n = 8 306 244). Patients with a history of cancer or active cancer were defined as having at least one ICD-10 ‘C’ diagnosis code, and patients with ATE and/or VTE as having at least one of I21/I24 (myocardial infarction), I63/I64 (stroke), I74 (arterial embolism), and I26/I80/I82 (venous thromboembolism) diagnosis code. Among 158 675 people with cancer, 8559 (5.4%) had an ATE diagnosis code and 7244 (4.6%) a VTE diagnosis code. In contrast, among 8 147 569 people without cancer, 69 381 (0.9%) had an ATE diagnosis code and 29 307 (0.4%) a VTE diagnosis code. This corresponds to age-stratified random-effects relative risks (RR) of 6.88 [95% confidence interval (CI) 4.81–9.84] for ATE and 14.91 (95% CI 8.90–24.95) for VTE. ATE proportion was highest in patients with urinary tract malignancies (RR: 7.16 [6.74–7.61]) and lowest in patients with endocrine cancer (RR: 2.49 [2.00–3.10]). The corresponding VTE proportion was highest in cancer of the mesothelium/soft tissue (RR: 19.35 [17.44–21.47]) and lowest in oropharyngeal cancer (RR: 6.62 [5.61–7.81]).

Conclusion

The RR of both ATE and VTE are significantly higher in persons with cancer. Our population-level meta-data indicate a strong association between cancer, ATE and VTE, and support the concept of shared risk factors and pathobiology between these diseases.

Relative risk of ATE and VTE in persons with a cancer diagnosis code versus persons without a cancer diagnosis code.
Tobacco taxes for improving welfare and distributional outcomes: the case of Georgia
Authors: Fuchs Tarlovsky Alan , González Icaza María Fernanda
Published: March 2021

Background

Georgia has one of the highest smoking prevalence and tobacco-related morbidity and mortality rates in Europe and Central Asia. Nonetheless, tax increases on tobacco products are often opposed due to concerns of regressive fiscal effects. This article provides evidence on the long-term welfare and distributional impacts of increasing cigarette taxes in Georgia.

Methods

An Extended Cost-Benefit Analysis is used to simulate the distributional effect of raising taxes on cigarettes. It weighs short-term losses due to higher tobacco prices with long-term benefits related to reduced medical expenses and additional earnings associated with extended life expectancy. Household expenditure data are used to estimate decile-specific price elasticities of demand for cigarettes, accounting for heterogeneous behavioral responses by income-group.

Results

Consistent with previous literature, cigarettes price elasticity decreases with income. A simulated 50% cigarette price increase would yield positive net gains for the lowest three deciles; increase the available income of the poorest 10% of the population by an average of 1% and, as a result, lift up to 7000 people out-of-poverty in 2017. The effects would be highly progressive.

Conclusions

As lower-income households tend to be more responsive to price changes on cigarettes, they stand to benefit most from the health and economic consequences of taxing tobacco. This article shows that in addition to boosting fiscal revenues, increasing cigarette prices would lead to progressive and positive net gains for the poorest households in Georgia.
False Readiness: Expanding the Concept of Readiness in Conflict Resolution Theory
Authors: Schwartz Adi , Gilboa Eytan
Published: March 2021

This study introduces a new theoretical concept, “false readiness” (FR), to fill a lacuna in theories of conflict resolution (CR). Existing theories focus mostly on successful cases and opening phases and suggest conditions and variables to determine whether a conflict is “ripe” or “ready” for resolution. The prevailing assumption is that if disputants decide to enter negotiations, they must have “crossed the Rubicon” and wish to reach agreement. This is not always the case in protracted conflicts where parties enter negotiations for reasons other than reaching peace. Existing CR theories do not adequately address this phenomenon. Negotiation theories do explore dishonest intentions but describe them as side effects, short lived and tactical. They also offer too many overlapping and confusing concepts that for the purposes of this study had to be clarified, categorized, and modified. The main goal of this work is not to create an entirely new theory, but rather to add a new theoretical layer to the readiness theory of CR that would be capable of investigating failures to resolve protracted conflicts. The layer is based on the integration of the readiness theory with concepts from negotiation theory that explore conditions where parties negotiate without intention to achieve agreement. FR addresses dubious intentions as strategic and long run that can span multiple stages in CR processes, not only the opening one.
Detection of Monema flavescens (Lepidoptera: Limacodidae) Cocoons Using Small Unmanned Aircraft System
Authors: Park Yong-Lak , Cho Jum Rae , Lee Gwan-Seok , Seo Bo Yoon
Published: March 2021

Current unmanned aircraft system (a.k.a. drone) technology is an effective tool for aerial survey of pests including weeds, plant diseases, and insects. This study was conducted to develop an aerial survey method that can locate cocoons of the oriental moth, Monema flavescens Walker, for precise and accurate detection of the cocoons in winter to prevent defoliation in the subsequent summer. We used a rotary-wing drone for an aerial survey of M. flavescens cocoons on 15 trees at 3–5 m above the tree canopy. We also conducted a conventional ground survey of M. flavescens cocoons on the same trees for two different conditions of cocoons: open (i.e., adult moths already emerged from cocoons) and closed (i.e., adult moths were not emerged yet). A validation census with destructive sampling was conducted to determine the precision and accuracy of the aerial and ground survey methods. The results of this study showed that from the aerial survey with the drone, images of open cocoons differed from those of closed cocoons. We found higher precision and accuracy and lower type I and II error rates for closed cocoons by the aerial survey with the drone than those by the ground survey. No significant relationships of the number of cocoons with tree height and diameter at breast height were found. This is the first study to demonstrate direct detection of insects with an aerial survey by using a drone.
The Food Allergy Parent Mentoring Program: A Pilot Intervention
Authors: Ramos Ashley , Cooke Frances , Miller Emily , Herbert Linda
Published: March 2021

Objective 

Parents of young children with newly diagnosed food allergy (FA) are at risk for poor psychosocial outcomes due to FA’s life-threatening nature and demanding management routines. Presently, there are no interventions to support FA parents during this adjustment phase. This single-arm pilot study explores the feasibility, acceptability, and preliminary efficacy of a novel intervention using peer mentorship to improve psychosocial functioning in parents of young children with newly diagnosed FA.

Methods 

Parent mentors were trained in mentorship and ethics and then matched with a mentee for a 6-month intervention period. Mentees, parents of children (under age 5 years) diagnosed with FA within 1 year, completed baseline and follow-up questionnaires to assess demographic and medical characteristics, FA knowledge, quality of life, self-efficacy, and social support and a program evaluation. Follow-up focus groups with mentors and individual interviews with mentees were conducted.

Results 

Participants were 8 mentors and 10 mentees (Mage = 36.60 years, 80% Caucasian) of children ages 0–3 years (Mage = 16.15 months; 60% male). Mentees reported high acceptability for the intervention in program evaluation and interviews, noting improvements in their social support, FA-related stress, confidence in FA management, and positive changes in FA parenting behaviors.

Conclusion 

This study supports the use of a peer mentorship program to support parents of children with newly diagnosed FA. Future research is needed to determine how to scale this intervention to meet the needs of a large medical division.
Beyond Marginalization: The (German-)Jewish Soldiers’ Agency in Times of War, 1914–1918
Authors: Panter Sarah
Published: March 2021

This article rethinks research on Jewish experiences during the First World War and asks what changes if the concept of ‘agency’ is explicitly applied to the subject of Jewish soldiers. Over the past years, historians working on the (German-)Jewish war experience have avoided a one-sided narrative of Jewish marginalization by focusing on larger questions of civic and ethnic belonging. This article picks up this thread, putting emphasis on the possibilities and concrete manifestations of the (German-)Jewish soldiers’ agency and how it was negotiated between the war and the home fronts. It argues that by concentrating on Jewish soldiers as actors in their own right, a more ambivalent narrative becomes visible—one that sees Jews during the First World War not as marginalized subjects across the board. Even though many Jewish soldiers experienced exclusion on an individual and collective level, their coming to terms with what it meant to be a soldier and a Jew during the war frequently triggered a process of Jewish reorientation as well. Bringing these two perspectives together, I show how Jews in and outside Germany were not simply bystanders during the national crisis, but took an active part in shaping their own history.
A full relativistic thin disc – the physics of the plunging region and the value of the stress at the ISCO
Authors: Potter William J
Published: March 2021

The widely used Novikov–Thorne relativistic thin disc equations are only valid down to the radius of the innermost stable circular orbit (ISCO). This leads to an undetermined boundary condition at the ISCO, known as the inner stress of the disc, which sets the luminosity of the disc at the ISCO and introduces considerable ambiguity in accurately determining the mass, spin, and accretion rate of black holes from observed spectra. We resolve this ambiguity by self-consistently extending the relativistic disc solution through the ISCO to the black hole horizon by calculating the inspiral of an average disc particle subject to turbulent disc forces, using a new particle-in-disc technique. Traditionally it has been assumed that the stress at the ISCO is zero, with material plunging approximately radially into the black hole at close to the speed of light. We demonstrate that in fact the inspiral is less severe, with several (∼4–17) orbits completed before the horizon. This leads to a small non-zero stress and luminosity at and inside the ISCO, with a local surface temperature at the ISCO between ∼0.15 and 0.3 times the maximum surface temperature of the disc, in the case where no dynamically important net magnetic field is present. For a range of disc parameters we calculate the value of the inner stress/surface temperature, which is required when fitting relativistic thin disc models to observations. We resolve a problem in relativistic slim disc models in which turbulent heating becomes inaccurate and falls to zero inside the plunging region.
Consistency of cosmic shear analyses in harmonic and real space
Authors: Doux C , Chang C , Jain B , Blazek J , Camacho H , Fang X , Gatti M , Krause E , MacCrann N , Samuroff S , Secco L F , Troxel M A , Zuntz J , Aguena M , Allam S , Amon A , Avila S , Bacon D , Bertin E , Brooks D , Burke D L , Carnero Rosell A , Carrasco Kind M , Carretero J , Choi A , Costanzi M , Crocce M , da Costa L N , Pereira M E S , Davis T M , Dietrich J P , Doel P , Ferrero I , Ferté A , Fosalba P , García-Bellido J , Gaztanaga E , Gerdes D W , Gruen D , Gruendl R A , Gschwend J , Gutierrez G , Hartley W G , Hinton S R , Hollowood D L , Huterer D , James D J , Kuehn K , Kuropatkin N , Maia M A G , Marshall J L , Menanteau F , Miquel R , Morgan R , Palmese A , Paz-Chinchón F , Plazas A A , Roodman A , Sanchez E , Schubnell M , Serrano S , Sevilla-Noarbe I , Smith M , Soares-Santos M , Suchyta E , Tarle G , To C , Varga T N , Weller J , Wilkinson R D ,   (DES Collaboration)
Published: March 2021

Recent cosmic shear studies have reported discrepancies of up to 1σ on the parameter ${S_{8}=\sigma _{8}\sqrt{{\Omega _{\rm m}}/0.3}}$ between the analysis of shear power spectra and two-point correlation functions, derived from the same shear catalogues. It is not a priori clear whether the measured discrepancies are consistent with statistical fluctuations. In this paper, we investigate this issue in the context of the forthcoming analyses from the third year data of the Dark Energy Survey (DES Y3). We analyse DES Y3 mock catalogues from Gaussian simulations with a fast and accurate importance sampling pipeline. We show that the methodology for determining matching scale cuts in harmonic and real space is the key factor that contributes to the scatter between constraints derived from the two statistics. We compare the published scales cuts of the KiDS, Subaru-HSC, and DES surveys, and find that the correlation coefficients of posterior means range from over 80 per cent for our proposed cuts, down to 10 per cent for cuts used in the literature. We then study the interaction between scale cuts and systematic uncertainties arising from multiple sources: non-linear power spectrum, baryonic feedback, intrinsic alignments, uncertainties in the point spread function, and redshift distributions. We find that, given DES Y3 characteristics and proposed cuts, these uncertainties affect the two statistics similarly; the differential biases are below a third of the statistical uncertainty, with the largest biases arising from intrinsic alignment and baryonic feedback. While this work is aimed at DES Y3, the tools developed can be applied to Stage-IV surveys where statistical errors will be much smaller.