bluuebunny/crossref_metadata_2025 huggingface dataset:
Root Cause Analysis of Fires in Coal Power Plants Using RFMEA Methods
Authors: Nugroho M J , Bahartyan E , Raymond R , Hidayat B , Irawan M I
Published: March 2021

Fire is one of the highest risks in using coal as fuel for electricity generation. Coal fires often occur in the area of coal handling facilities and are caused by equipment damage, accumulation of coal dust that has not been cleaned and burning coal itself. This study aims to find out how the application of the RFMEA (Risk Failure Mode Effect Analysis) method for the analysis of the root causes of fires in the Pacitan Coal Fired Power Plant case study uses a quantitative approach to find the root causes of prevention by respondents. from PT. PJB UBJOM Pacitan at manager and supervisor level. In implementing RFMEA, the severity, events, and detection are needed to produce risk level figures which will be used as a step in determining the priorities of the company’s mitigation management. Based on this study, 15 types of equipment failures were found at the operational coal handling facility at PT PJB UBJOM PACITAN. By using the RFMEA method, 1 type of critical failure can be found that requires more attention from management to mitigate the risk immediately, namely dust on coal both from barges and coal yards with risk value 32.05.
Optimization of Sedimentation System through AHP and AHP-TOPSIS Methods in Water Treatment Steam Power Plant
Authors: Feriyanto Y E , Zulfikar S P , Dedy
Published: March 2021

Steam power plants consist of systems such as Water Treatment Plant (WTP), boiler, turbine-generator, and balance of plant. WTP system consists of sedimentation, desalination, and demineralization. The coagulation mechanism triggered by the mass grave of suspended solids during the sedimentation process, and if it is less than optimal, so will be modified by injecting coagulant-flocculant chemicals. The most common problem is the high dose chemicals used in the rain and tidal sea conditions. However, the output water quality that produced still does not reach the standard requirements. This condition would affect the high costs of water treatment operations. It also would have an impact on the poor feed the next system. The jar-testing technique is research using process and operational variables that theoretically influence the efficiency of the coagulant-flocculant such as doses, setting times, and rotates agitator. Evaluation of experiments using water quality criteria and data results processed by AHP and AHP-TOPSIS. The sensitivities of both methods are analyzed thus compared to select a consistent alternative that obtained sequence the first alternative for D60W30P80 and the second alternative for D40W20P80. The optimal sedimentation process could potentially save 40-60% of the water treatment operational cost while operating conditions achieved.
Re-design and Upgrade Bearing Materials Traveling Drum Screen in Muara Karang Combined Cycle Power Plant Block 1
Authors: Kurniawan A , Kusuma E
Published: March 2021

The cooling system in the Steam Turbine Generator (STG # 1.0) is adjusted to the cleanliness conditions of seawater, using Traveling Drum Screen (TDS) as a filter. In January 2019, Traveling Drum Screen (TDS) suffered bearing and fuse bolt damage until STG # 1.0 was stopped with a potential loss of 28.59 billion rupiahs. The position of the TDS bearing below the surface of the sea makes monitoring difficult. To overcome the problems in TDS bearings, an innovation was made in the form of redesign & upgrading bearing materials. The replacement of TDS bearing material from Pertinax to Pokhout Wood (Lignum vitae) is very appropriate because the material is capable of self-lubrication in seawater and has more strength. In addition to upgrading the material, a redesign of the bearing is also carried out, which is adding a grease groove so that the optimal lubrication process and use finite analysis software to find out safety factors design. By using simulation software, the results show the bearing design with Pokhout material has a safety factor of 1.28 and Pertinax has a safety factor of 0.85. This shows that the re-design and upgrade of materials that have been carried out can increase the safety factor bearing and can reduce the possibility of failure of the bearing.
Study of Counterweight Addition to Improve Structural Stability of Ship Unloader at Pulang Pisau CFPP
Authors: Huda K , Safii A , Priyono A
Published: March 2021

The ship unloader at Pulang Pisau CFPP is a crane type machine that is used to transport coal from barges to stockpile. This machine uses slewing bearing as component that support for slewing movement to transport coal from the barge to the belt conveyor. Meanwhile this machine also has boom that moves up and down to lift the coal towards to the hopper provided. Several times the slewing bearing was damage with the failure mode is lifted up the inner race bearing and causing the roller inside damaged. Investigation and testing are carried out to find out the strength of the structure and what are the forces that acted. From the results of the investigation and testing, it was found that the ship unloader suffered excessive moment in the front side (boom side), thus making the bearing was fruquently damaged. And the limitation about lifting angle of boom is considered. This study tries to find the balance of forces, moments, and lifting angle, and then to add a counterweight that are sufficient to reduce the impact of the unbalance moment with limitation of boom lifting angle. With the addition of counterweight and limitation angle of boom make the moments are more stable to the structure, and so the lifetime of slewing bearing is longer.
Failure Investigation of Repetitive Crack on MW-701D Gas Turbine Exhaust Manifold
Authors: Laksana W A , Santosa A , Suwarno  , Swastika P A , Dhimas N C
Published: March 2021

A gas turbine power plant is the best choice for peak load conditions in power generation. As we know using gas turbine need less time to start and stop operation than a coal-fired power plant. In East Java, Indonesia has 9unit Gas Turbine Power Plant, which usually operates in peak load conditions. In this paper, a study will carry out an investigation based on maintenance data history which since 2010 founded repeatedly crack in the exhaust manifold. Failure Investigation in the exhaust manifold has been carried so that repetitive crack can be handled in the future. The crack location was mapped to found the root cause of failure. Fuel consumption and operation condition was analyzed to find the cause of the crack. Analysis with fluent software found that streamline of flue gas makes a turbulency in the spotted area. Material selection and design no free expansion in the exhaust manifold increase possibility of failure.
Determination of VAR Compensator Placement for System Stability Improvement on Java Bali Network
Authors: Apriyanto A E , Virgiawan A R , Pariaman H , Hisjam M , Hariyanto N
Published: March 2021

Quality of a power system network can be evaluated from its voltage performance. There are several bus/substation of Java Bali networks that frequently operate in unsatisfied voltage level. As an important part of Indonesian electricity system, quality improvement of this network should be sustainably maintained. The occurring problem can be solved by reactive power compensation. Compensation can be done by installing reactive power compensator into the network. To get an optimal improvement level of voltage performance, the installation location of reactive power compensator must be carefully selected. The selection process can be done by consider the operating voltage, bus sensitivity factor, power angle sensitivity factor and geographic location factor on each location in the network. With consideration of these parameters then the optimal location and configuration of the reactive power compensator can be obtained.
Using fuzzy sampling survey to explore the factors influencing regional cooperation: Changsha-Zhuzhou-Xiangtan case
Authors: Li Chaojun , Chang Kuo Kuang , Ou Shih Ming
Published: March 2021

A comprehensive and profound understanding of the factors influencing regional tourism cooperation is the key to promoting regional tourism cooperation and is the leading condition for deepening the study of regional tourism cooperation economic incentives and cooperation mechanisms. Based on the literature review, a conceptual framework model for analyzing the factors influencing regional tourism cooperation was constructed, and these factors were systematically classified and analyzed. Using fuzzy sampling survey, we distinguished the endogenous and exogenous factors influencing regional tourism cooperation. After the data we collected was processed, we found that economic factors and simple cost-benefit analysis were very important in the start-up phase of regional tourism cooperation; however, as cooperation advanced, the factors that hindered and promoted tourism cooperation should be analyzed in a larger context. At the end of the article, the new organizational economics theory was used to explain this phenomenon, and the basic countermeasures for promoting regional tourism cooperation were put forward.
Integration of intelligent diagnosis system and augmented reality for electric motors
Authors: Lin Yu Ching , Kan Heng Chuan , Lu Jian Ming , Yao Chih Min , Liao Yu Chia , Chung Chun Hui , Shih Kai Chung , Tsai Mi Ching
Published: March 2021

With the rapid development of industrial automation technology, electric motor control has also become an important technology. However, motor failure has many possible causes, and it is not easy to detect in advance. Therefore the fault diagnosis is an important issue for motors. The augmented reality (AR) technology is also developing towards various industrial and educational application in recent years. This research is focused on developing the intelligent diagnosis system and AR application for electric motors. The intelligent diagnosis system applies cloud data management and machine learning methods to predict the health status of electric motors. And the time-recurrent Long Short-Term Memory (LSTM) neural network algorithm is applied to establish a motor health diagnostic model. The experimental results show that the motor diagnosis method can predict the health status of motor effectively. The proposed system will also provide more industrial application services in the future.
Optimal perturbations in viscous channel flow with crossflow
Authors: Chen Cheng , Huang Jiang-Tao , Zhang Wei-Guo
Published: March 2021

This work is devoted to the studies of optimal perturbation and its transient growth characteristics in the Poiseuille flow with Reynolds number R = 1000 and with crossflow. The crossflow Reynolds number R

v
, based on the uniform velocity in the negative normal direction, is varied from 0 to 200. The numerical result shows that the crossflow enhances the transient growth for three-dimensional disturbance case when

R
v

<
17.9

. Seen from the contours of optimal energy growth in the wave number plane, the optimal perturbation that corresponds to the peak value of optimal growth becomes oblique perturbation, when crossflow is introduced. The corresponding streamwise wave number α

P
increases continuously with increasing R

v
, while spanwise wave number β

P
drops firstly with increasing R

v
and later increases. The comparison of exponential growth and transient growth is performed. It is observed that exponential growth becomes profound and even predominant over transient growth after a short period when the crossflow is sufficiently strong. Moreover, the mechanism of transient growth is discussed and it is found that the uniform crossflow can not cause transient growth in the absence of shear in basic flow. With increasing R

v
, the Orr mechanism becomes more and more important relative to lift-up mechanism for the transient growth of optimal perturbation.
Electrochemical performance comparison study of ternary RGO/ß-Ni(OH)2-CeO2 nanocomposite prepared from hydrothermal and solid-state methods for supercapacitors
Authors: Godlaveeti Sreenivasa Kumar , Jangiti Sravani , Bharatiya Debasrita , Somala Adinarayana Reddy , Sana Siva Sankar , Nagireddy Ramamanohar Reddy
Published: March 2021

In this paper, a novel ternary RGO/β-Ni(OH)2-CeO2 nanocomposite (NC) was synthesised through facile, one-step hydrothermal, and solid-state methods. The structural, morphological, and elemental composition analyses of powder composites were characterised by various techniques such as XRD, FTIR, TEM, and EDX. The electrochemical performance of RGO/β-Ni(OH)2-CeO2 composites prepared by hydrothermal and solid-state methods coated on Ni foam in presence of 3 M KOH an aqueous solution was studied through CV, GCD, and EIS techniques. The specific capacitance of 788 F g−1 achieved at a current density 0.5 A g−1 was observed for the SSM-2 sample at 250 °C calcination temperature as a result of the synergic effect and combination of RGO, β-Ni(OH)2, CeO2 compounds. The obtained electrochemical results show that the present novel ternary RGO/β-Ni(OH)2-CeO2 working electrode fabricated from the solid-state method is suitable for the next generation supercapacitor applications.
A novel approach for detecting undercuts within surface textures generated by Electrochemical Jet Machining (ECJM)
Authors: Lazzini Gianmarco , Romoli Luca , Kunieda Masanori
Published: March 2021

The present study proposes a novel method for detecting micrometric undercuts (UCs) generated by electrochemical machining for the production of surfaces with tailored functionality. Two different algorithms for the detection of UCs based on two-dimensional topographic maps are tested. The first is a traditional approach based on definition of UCs in terms of surface orientation with respect to a reference direction. The second is an innovative alternative approach designed to reduce sensitivity to numerical effects that potentially lead to overestimation of the number of detected UCs. Electrochemical Jet Machining (ECJM) is used to texture SUS 316L specimens with the aim of producing a measurable surface with a representative number of micrometric UCs. Generated surface textures, comprising craters with diameters ranging from a few microns to tens of microns, are cross-sectioned and inspected with Scanning Electron Microscopy. The extracted profiles allow the novel method for detection of UCs to be efficiently tested and compared with the traditional approach. The number of UCs is found to decrease with increasing electrolyte jet scanning speed, while remarkable differences are revealed between the two calculation approaches at scanning speeds below 2 mm s−1.
Analyzing the mechanical and wear behavior of age hardening processed AZ31 magnesium composites
Authors: P Seenuvasaperumal , Elayaperumal A , Kumar Paskalis Sahaya Murphin , Arulvel S
Published: March 2021

The usage of AZ31 magnesium alloy has been limited in tribology applications, due to low hardness and poor wear resistance. In this connection, the age-hardening process is a promising heat treatment process for enhancing mechanical strength and wear resistance. Hence, the present work aims to analyze the effect of the age-hardening process on the microstructure, mechanical and wear behavior of AZ31 Magnesium-Calcium hexaboride composites (Mg composite). Here, dry sliding wear behavior was analyzed with different loads (10, 20, and 30 N) and sliding velocity (0.4, 0.6, and 0.8 m. s−1) for a constant sliding distance of 2000m. Age hardened composites exhibited a higher hardness and compressive strength which was due to the increased volume of the secondary precipitates (Mg17Al12 and Al8Mn5). The morphology study revealed that there is an exhibition of shear bands and brittle fracture for Age hardened composites. The remarkable wear rate reduction was achieved for age hardening processed composites due to the increased load-bearing capacity induced by the presence of a high volume of secondary precipitates. Delamination wear is the dominant wear mechanism for the composites and the delaminated craters increases with increasing the load condition. Further, the elemental mapping on the collected wear debris was also used to confirm the wear mechanism.
Nonlinear flexure mechanics of beams: stress gradient and nonlocal integral theory
Authors: Fazlali Mahdad , Moghtaderi Saeed H , Faghidian S Ali
Published: March 2021

In order to study the intrinsic size-effects, the stress gradient theory is implemented to a nano-scale beam model in nonlinear flexure. The nonlocal integral elasticity model is considered as a suitable counterpart to examine the softening behavior of nano-beams. Reissner variational principle is extended consistent with the stress gradient theory and applied to establish the differential, constitutive and boundary conditions of a nano-sized beam in nonlinear flexure. The nonlinear integro-differential and boundary conditions of inflected beams in the framework of the nonlocal integral elasticity are determined utilizing the total elastic strain energy formulation. A practical series solution approach in terms of Chebyshev polynomials is introduced to appropriately estimate the kinematic and kinetic field variables. A softening structural behavior is observed in the flexure of the stress gradient and the nonlocal beam in terms of the characteristic parameter and the smaller-is-softer phenomenon is, therefore, confirmed. The flexural response associated with the stress gradient theory is demonstrated to be in excellent agreement with the counterpart results of the nonlocal elasticity model equipped with the Helmholtz kernel function. The nonlocal elasticity theory endowed with the Error kernel function is illustrated to underestimate the flexural results of the stress gradient beam model. Detected numerical benchmark can be efficiently exploited for structural design and optimization of pioneering nano-engineering devices broadly utilized in advanced nano-electro-mechanical systems.
Research on the dynamic mechanical properties and constitutive model of metal rubber under impact loading
Authors: Zou Youchun , Xiong Chao , Yin Junhui , Cui Kaibo , Zhu Xiujie , Deng Huiyong , Song Shijun
Published: March 2021

The development of lightweight, impact-resistant and high energy dissipation materials is of great significance to reduce the hazards of explosions and impacts. Metal rubber (MR) has the characteristics of low density, high damping performance and high elasticity, which shows great potential in the field of protection. However, there are few studies on the dynamic mechanical response of MR under high-speed impact. A series of experiments were carried out to study the mechanical properties of MR. It is found that the deformation mechanism of the metal wire inside the MR determines the mechanical properties. Under quasi-static conditions, the stress-strain of MR includes an elastic stage, a softening stage and a hardening stage, and the stress-strain under high-speed impact includes an elastic stage, a softening stage and a failure stage. In addition, the smaller the wire diameter, the higher the load-bearing capacity of the MR. The damage characteristics of MR under high-speed impact are divided into expansion failure and compaction failure, which will affect mechanical performance in the failure stage. The calculated energy absorption and ideal energy absorption efficiency show that MR is a material with excellent energy absorption properties. The dynamic elastic modulus and dynamic peak stress of MR have strain rate effect and density effect. A constitutive model based on Sherwood-frost equation was established, which can precisely forecast the dynamic mechanical properties.
The impact of Fe/Mn loads on the surface property of rare earth mineral
Authors: Bai Yuze , Zhu JinHao , Luo HuiJuan , Wang ZhenFeng , Wu Wenfei , Zhang Kai
Published: March 2021

After using the mixed acid system to modify the surface of rare earth minerals, two transition metals (Fe and Mn) are loaded on the surface of the rare earth minerals by hydrothermal method to improve the NH3-SCR (Selective catalytic reduction) activity. In this paper, a variety of characterization means like SEM, XRD, BET, XPS, H2-TPR (Temperature-programmed reduction), NH3-TPD (Temperature-programmed desorption) and NO-TPD are used to study and analyze the surface properties of rare earth minerals before and after loading transition metals. Its catalytic performance was further measured in a simulated flue gas installation. The results show that the active elements on the surface of rare earth minerals after loading transition metals are mainly oxides. The specific surface area of rare earth minerals is effectively improved, the crystallinity of the active material is reduced, and the element distribution is more uniform. In addition, a composite structure of Fe-Ce and Mn-Ce is formed on the surface of rare earth minerals, and the oxygen vacancies and adsorption sites on the surface of the minerals are significantly improved. The NOXconversion rate for Fe-loaded mineral catalysts reached 89.1% at 300 ℃. The NOXconversion rate for Mn-loaded mineral catalysts reached 92.3% at 250 ℃. Generally speaking, the NH3-SCR activity of rare earth mineral can be improved by loading transition metals (Fe and Mn).
Sustainable paths to a circular economy: reusing aged Li-ion FePO4 cathodes within Na-ion cells
Authors: Gucciardi Emanuele , Galceran Montserrat , Bustinza Ainhoa , Bekaert Emilie , Casas-Cabanas Montse
Published: March 2021

Responsible disposal and recycling are essential for the sustainability of the battery market, which has been exponentially growing in the past few years. Under such a scenario, the recycling of materials of less economic value, but environmentally much more sustainable like LiFePO4, represents an economic challenge. In this paper an approach to recover used FePO4 electrodes from calendar aged Lithium-ion (Li-ion) batteries and their reuse in Sodium-ion (Na-ion) cells is proposed. The electrochemical performances of the Na-ion cell are shown to be comparable with previously reported values and, since the electrode can retain the original microstructure and distribution, electrode processing can be avoided. A proof of concept of a NaFePO4//hard carbon full cell using a very high positive electrode loading optimized for Li-ion batteries (≈14 mg cm−2) is shown.
Rhinoplasty in the Older Adult
Authors: Khetpal Sumun , Gowda Arvind U , Parsaei Yassmin , Mozaffari Mohammad Ali , Dinis Jacob , Lopez Joseph , Steinbacher Derek
Published: March 2021

Background

Rhinoplasty in older adults requires unique consideration of the aging nose.

Objectives

The purpose of this study was to systematically review the literature pertaining to rhinoplasty in the aging population, review the senior author’s experience, and describe techniques aimed at addressing age-related features. It was hypothesized that consistent age-related nasal dysmorphology is described in the literature and standard rhinoplasty techniques may effectively address these changes. Furthermore, it was hypothesized that rhinoplasty is more commonly performed for posttraumatic and functional indications than for aesthetic reasons.

Methods

A literature review including publications describing rhinoplasty in patients over 55 years old was conducted. Additionally, a retrospective review of the senior author’s cases was performed. Pre- and postoperative photographs were used to compare anthropometric changes. Demographic factors, surgical indications, and operative details were collected.

Results

Nine articles met the study criteria. Manifestations of the aging nose included soft tissue atrophy, bony fragility and resorption, tip ptosis, internal and external valve collapse, and worsening dorsal hump. Twenty-seven patients were included in this institutional review. Primary indication for rhinoplasty was posttraumatic deformity in 17 (63%) patients and nasal obstructive symptoms in 10 (37%) patients. Tip refinement and ptosis were addressed through tip grafts (70%), columellar struts (26%), and caudal septal extension grafts (67%). Nasal obstruction was relieved through septoplasty (96%), turbinate ablation (85%), and spreader grafts (70%).

Conclusions

This study presents a systematic review of rhinoplasty in the older adult as well as a retrospective review of the senior author’s patients. Unique considerations specific to this population should be integrated into treatment planning.

Level of Evidence: 4
Impact of COVID-19 on surgical emergencies: nationwide analysis
Authors: Lazzati A , Raphael Rousseau M , Bartier S , Dabi Y , Challine A , Haddad B , Herta N , Souied E , Ortala M , Epaud S , Masson M , Salaün-Penquer N , Coste A , Jung C
Published: March 2021

Background

The COVID-19 pandemic has had a major impact on healthcare in many countries. This study assessed the effect of a nationwide lockdown in France on admissions for acute surgical conditions and the subsequent impact on postoperative mortality.

Methods

This was an observational analytical study, evaluating data from a national discharge database that collected all discharge reports from any hospital in France. All adult patients admitted through the emergency department and requiring a surgical treatment between 17 March and 11 May 2020, and the equivalent period in 2019 were included. The primary outcome was the change in number of hospital admissions for acute surgical conditions. Mortality was assessed in the matched population, and stratified by region.

Results

During the lockdown period, 57 589 consecutive patients were admitted for acute surgical conditions, representing a decrease of 20.9 per cent compared with the 2019 cohort. Significant differences between regions were observed: the decrease was 15.6, 17.2, and 26.8 per cent for low-, intermediate- and high-prevalence regions respectively. The mortality rate was 1.92 per cent during the lockdown period and 1.81 per cent in 2019. In high-prevalence zones, mortality was significantly increased (odds ratio 1.22, 95 per cent c.i. 1.06 to 1.40).

Conclusion

A marked decrease in hospital admissions for surgical emergencies was observed during the lockdown period, with increased mortality in regions with a higher prevalence of COVID-19 infection. Health authorities should use these findings to preserve quality of care and deliver appropriate messages to the population.
Acute Page kidney after angioplasty in kidney transplant allografts
Authors: Canllavi Elizabeth , Teigell Julio , Trujillo Hernando , Gutiérrez Eduardo , Sánchez Angel , Miranda-Utrera Natalia , Morales Enrique
Published: March 2021

Acute Page kidney (APK) in kidney transplantation is a rare entity often related to interventional techniques. Percutaneous angioplasty remains an exceptional cause of APK. Herein we describe the clinical course and outcome of APK following percutaneous angioplasty for transplant renal artery stenosis in four kidney transplant recipients, where external compression of the graft was caused by subcapsular haematomas. All patients were treated with surgical drainage, after which two cases recovered baseline kidney function, one developed advanced chronic kidney disease and one remained dialysis-dependent. To our knowledge, the present series is the largest to describe APK in kidney allografts after percutaneous angioplasty.
Learning Saliency-Aware Correlation Filters for Visual Tracking
Authors: Wang Yanbo , Wang Fasheng , Wang Chang , Sun Fuming , He Jianjun
Published: March 2021

Recently, visual object tracking has become a hot topic in computer vision community owing to its extensive applications and fundamental research significance. Many researchers have paid attention to the discriminative correlation filter (DCF) due to its excellent tracking performance. The background-aware CF (BACF) is developed to handle the inevitable boundary effects of DCFs that shows superior performance compared with other CF-based trackers. However, BACF has a poor occlusion handling ability. To overcome this defect, we propose a saliency-aware CF tracking (SACF) model. In SACF, a saliency map of the target is introduced on CFs to strengthen the ability to extract the target from a complex background. Meanwhile, to adjust to the rapid variation of the target appearance, we adaptively modify the learning rate of the filter template using adaptive learning rate. By incorporating the saliency map into the BACF objective function and adaptive learning rate adjustment, the robustness and accuracy of the tracker are boosted significantly. Extensive experiments validate that our method can efficaciously solve the occlusion problem and achieves state-of-the-art performance in terms of accuracy and speed on standard benchmarks, i.e. OTB-2013, OTB-2015 and LaSOT. Compared with other state-of-the-art CF tracking methods, the proposed method is competitive considering accuracy and success rate.
The Surplus Approach, Institutions, And Economic Formations
Authors: Cesaratto Sergio , Di Bucchianico Stefano
Published: March 2021

The paper develops Pierangelo Garegnani’s notion of the ‘core’ of the classical theory of distribution to propose a wider integration of the concept of social surplus and institutions into economic thinking. Its main tenet is that the social surplus does not exist independently of the institutions (or social order) that oversee its production and distribution, starting from those that prevail in the sphere of production. In this sense, we supplement the surplus approach with important insights not only from the Polanyian approach, from economic archaeology and anthropology, but also from Sraffian authors and Sraffa’s manuscripts. Taking inspiration from Garegnani, this work is offered as a prelude to the design of different economic ‘cores’ for different stylized economic formations.
Exponential discounting in security games of timing
Authors: Merlevede Jonathan , Johnson Benjamin , Grossklags Jens , Holvoet Tom
Published: March 2021

Strategic game models of defense against stealthy, targeted attacks that cannot be prevented but only mitigated are the subject of a significant body of recent research, often in the context of advanced persistent threats (APTs). In these game models, the timing of attack and defense moves plays a central role. A common assumption, in this literature, is that players are indifferent between costs and gains now and those in the distant future, which conflicts with the widely accepted treatment of intertemporal choice across economic contexts. This article investigates the significance of this assumption by studying changes in optimal player behavior when introducing time discounting. Specifically, we adapt a popular model in the games of timing literature, the FlipIt model, by allowing for exponential discounting of gains and costs over time. We investigate changes of best responses and the location of Nash equilibria through analysis of two well-known classes of player strategies: those where the time between players’ moves is constant, and a second class where the time between players’ moves is stochastic and exponentially distributed. By introducing time discounting in the framework of games of timing, we increase its level of realism as well as applicability to organizational security management, which is in dire need of sound theoretic work to respond to sophisticated, stealthy attack vectors.
Association between age and neurological outcomes in out-of-hospital cardiac arrest patients resuscitated with extracorporeal cardiopulmonary resuscitation: a nationwide multicentre observational study
Authors: Miyamoto Yuki , Matsuyama Tasuku , Goto Tadahiro , Ohbe Hiroyuki , Kitamura Tetsuhisa , Yasunaga Hideo , Ohta Bon
Published: March 2021

Aims

Little is known about the difference in outcomes between young and old patients who received extracorporeal cardiopulmonary resuscitation (ECPR) for out-of-hospital cardiac arrest (OHCA). Therefore, we aimed to investigate the differences in outcomes between those aged ≥75 years and <75 years who experienced OHCA and were resuscitated with ECPR.

Methods and results

We performed a secondary analysis of a nationwide prospective cohort study using the Japanese Association for Acute Medicine OHCA registry. We identified patients aged ≥18 years with OHCA who received ECPR. The patients were classified into three age groups (18–59 years, 60–74 years, and ≥75 years). The primary outcome was a 1-month neurological outcome. To examine the association between age and 1-month neurological outcome, we performed logistic regression analyses fitted with generalized estimating equations. From 2014 to 2017, we identified 875 OHCA patients aged ≥18 years who received ECPR. The proportion of patients who survived with favourable neurological outcome in the patients aged 18–59 years, 60–74 years, and ≥75 years were 15% (64/434), 8.9% (29/326), and 1.7% (2/115), respectively. In the multivariable analysis, compared with the age of 18–59 years, the proportions of favourable neurological outcomes were significantly lower in patients aged 60–74 years [adjusted odds ratio (OR), 0.44; 95% confidence interval (CI), 0.32–0.61] and those aged ≥75 years (adjusted OR, 0.26; 95% CI, 0.11–0.59).

Conclusion

Advanced age (age ≥75 years in particular) was significantly associated with poor neurological outcomes in patients with OHCA who received ECPR.
An overview ofSalmonella entericametal homeostasis pathways during infection
Authors: Cunrath Olivier , Palmer Jacob D
Published: March 2021

Nutritional immunity is a powerful strategy at the core of the battlefield between host survival and pathogen proliferation. A host can prevent pathogens from accessing biological metals such as Mg, Fe, Zn, Mn, Cu, Co or Ni, or actively intoxicate them with metal overload. While the importance of metal homeostasis for the enteric pathogen Salmonella enterica Typhimurium was demonstrated many decades ago, inconsistent results across various mouse models, diverse Salmonella genotypes, and differing infection routes challenge aspects of our understanding of this phenomenon. With expanding access to CRISPR-Cas9 for host genome manipulation, it is now pertinent to re-visit past results in the context of specific mouse models, identify gaps and incongruities in current knowledge landscape of Salmonella homeostasis, and recommend a straight path forward towards a more universal understanding of this historic host–microbe relationship.
Metabarcoding analysis suggests that flexible food web interactions in the eukaryotic plankton community are more common than specific predator–prey relationships at Helgoland Roads, North Sea
Authors: Käse Laura , Metfies Katja , Kraberg Alexandra C , Neuhaus Stefan , Meunier Cédric L , Wiltshire Karen H , Boersma Maarten
Published: March 2021

Various field studies on plankton dynamics have broadened our understanding of seasonal succession patterns. Additionally, laboratory experiments have described consumers ranging from generalists to selective grazers. While both approaches can give us a good understanding of the ecosystem and its dynamics, drawbacks in identification and a limited coverage of the ecosystem have left open questions on the generality of previous results. Using an integrative approach, we investigated water samples taken at Helgoland Roads by metabarcoding to describe seasonal succession patterns of the whole plankton community. By use of network analysis, we also tried to identify predator–prey dynamics. Our data set depicted the strong seasonality typically found for temperate waters. Despite a stable background community surviving strong fluctuations, small and abrupt changes, such as pronounced blooms and random appearance of autotrophs, cause seasons to be quite different in an inter-year comparison. Main consumers were copepods, ciliates, and dinoflagellates, of which the latter were most abundant. Furthermore, our results suggest that zooplankton predators might favour specific prey during certain time periods but seem to be quite opportunistic otherwise throughout the year. The variability and potential for many different relationships in the plankton community might be an indicator of resilience in the system.
Outcomes and complications of patients undergoing Salter’s innominate osteotomies for hip dysplasia: a systematic review of comparative studies
Authors: Tejpal Tushar , Shanmugaraj Ajaykumar , Gupta Arnav , Horner Nolan S , Simunovic Nicole , Kishta Waleed , Ayeni Olufemi R
Published: March 2021

The purpose of this systematic review is to assess outcomes and complications of patients undergoing Salter’s innominate osteotomies (SIOs) for the correction of hip dysplasia along with patient and technical factors that can be optimized to improve outcomes after SIO. MEDLINE and EMBASE were searched from data inception to 9 October 2018. Data were presented descriptively. Twenty-seven studies were identified including 1818 hips (87.1%) treated with SIO (mean age of 2.1 ± 2.5 years and mean follow-up of 3.5 ± 5.0 years). Patients undergoing SIO had a post-operative center-edge angle (CEA) of 31.3° ± 5.3° and an acetabular index (AI) angle of 16.1° ± 5.2°. Patients undergoing SIO with pre-operative traction had significantly lower (P = 0.049) post-operative McKay criteria scores compared to patients without pre-operative traction. Patients undergoing SIO between the ages of 1.5–2 years had significantly better (P < 0.05) post-operative McKay criteria scores compared to patients aged 4–6 years. The complication rate was 9.4% with avascular necrosis (2.5%) being most common. This review found that SIO for developmental dysplasia of the hip produces generally good post-operative clinical outcomes. The CEA and AI can be corrected to normal range after SIO. Patients may have superior outcomes if they have SIO at a younger age, were not treated with pre-operative traction and did not have untreated contralateral hip dysplasia. Outcomes appear to be similar between one-stage bilateral SIO and a two-stage procedure in the setting of bilateral hip dysplasia; however, more multicentered studies are needed to confirm these results.
Ear photosynthesis in C3 cereals and its contribution to grain yield: methodologies, controversies, and perspectives
Authors: Tambussi Eduardo A , Maydup María L , Carrión Cristian A , Guiamet Juan J , Araus Jose L
Published: March 2021

In C3 cereals such as wheat and barley, grain filling was traditionally explained as being sustained by assimilates from concurrent leaf photosynthesis and remobilization from the stem. In recent decades, a role for ear photosynthesis as a contributor to grain filling has emerged. This review analyzes several aspects of this topic: (i) methodological approaches for estimation of ear photosynthetic contribution to grain filling; (ii) the existence of genetic variability in the contribution of the ear, and evidence of genetic gains in the past; (iii) the controversy of the existence of C4 metabolism in the ear; (iv) the response of ear photosynthesis to water deficit; and (v) morphological and physiological traits possibly related to ear temperature and thermal balance of the ear. The main conclusions are: (i) there are a number of methodologies to quantify ear photosynthetic activity (e.g. gas exchange and chlorophyll fluorescence) and the contribution of the ear to grain filling (individual ear shading, ear emergence in shaded canopies, and isotope composition); (ii) the contribution of ear photosynthesis seems to have increased in modern wheat germplasm; (iii) the contribution of the ear to grain filling increases under resource-limitation (water deficit, defoliation, or pathogen infection); (iv) there is genetic variability in the contribution of the ear in wheat, opening up the possibility to use this trait to ameliorate grain yield; (v) current evidence supports the existence of C3 metabolism rather than C4 metabolism; (vi) the ear is a ‘dehydration avoider organ’ under drought; and (vii) thermal balance in the ear is a relevant issue to explore, and more research is needed to clarify the underlying morphological and physiological traits.
Responses to Gradual and Immediate Reduction of Nicotine in Cigarettes in Young Versus Older Adult Smokers
Authors: Cassidy Rachel N , Tidey Jennifer W , Cao Qing , Colby Suzanne M , McClernon Francis J , Smith Tracy T , Dermody Sarah , Koopmeiners Joseph S , Jensen Joni A , Strayer Lori G , Donny Eric C , Hatsukami Dorothy
Published: March 2021

Introduction

As the FDA works to determine whether a nicotine reduction policy would benefit public health, one key question is whether to mandate an immediate or gradual reduction in nicotine levels in cigarettes. The aim of this study was to determine whether the effects of gradual versus immediate nicotine reduction on cigarettes per day (CPD), total nicotine equivalents, and subjective responses differed in younger adults versus older adults.

Methods

Using data from a recent randomized trial conducted in the United States (N = 1250) that switched smokers over a 20-week period to very low nicotine content (VLNC) cigarettes either immediately, gradually (via monthly reductions in nicotine content), or not at all (control condition, normal nicotine content research cigarette), we analyzed the moderating effect of age (age 18–24 or 25+).

Results

For both age groups, CPD in the immediate condition was significantly lower relative to gradual condition (estimated mean difference of 6.3 CPD in young adults, 5.2 CPD in older adults; p’s < .05). Younger and older adults in the immediate and gradual reduction conditions had lower total nicotine equivalents at Week 20 (all p’s < .05) than those in the control condition; age group did not moderate this effect. Positive subjective responses to cigarettes were lower among young adults relative to older adults in the immediate condition.

Conclusions

These results indicate that an immediate reduction in nicotine would result in beneficial effects in both young and older adults. Young adults show less positive subjective effects of smoking following switching to VLNC cigarettes relative to older adults.

Implications

As researchers work to understand how a potential reduced-nicotine product standard for cigarettes may affect public health, one question is whether nicotine should be reduced immediately or gradually. This study demonstrates that both young and older adults who were switched immediately to the lowest content of nicotine smoked fewer CPD and had lower nicotine intake than those in the gradual condition. Furthermore, young adults appear to show lower positive subjective effects following switching to VLNC cigarettes relative to older adults. This is consistent with previous work demonstrating that young people appear to show lower abuse liability for VLNC cigarettes.
Associations Between Plasma Human Immunodeficiency Virus (HIV) Ribonucleic Acid Levels and Incidence of Invasive Cancer in People With HIV After Initiation of Combination Antiretroviral Therapy
Authors: Elvstam Olof , Marrone Gaetano , Medstrand Patrik , Treutiger Carl Johan , Svedhem Veronica , Gisslén Magnus , Björkman Per
Published: March 2021

Background

Human immunodeficiency virus (HIV) viremia could be involved in the increased risk of cancer in people with HIV (PWH) receiving combination antiretroviral therapy (cART). We analyzed the association between plasma HIV ribonucleic acid levels in PWH starting cART and incident invasive cancer using the Swedish cohort InfCare HIV linked with national registers.

Methods

Adults starting cART in 1996–2017 were included if they had ≥1 viral load (VL) measurement before receiving any antiretroviral agent (pre-ART VL) and ≥2 VLs ≥6 months after start of cART. Viremia during cART was analyzed both as viremia-copy-years and categorized as suppression (<50 copies/mL), low-level viremia ([LLV] 50–999 copies/mL), and nonsuppression (≥1000 copies/mL). The main outcome was a composite of invasive malignancies with increased incidence among PWH. We fitted proportional subhazard models (including sex, age, pre-ART CD4 count, and injection drug use) for both pre-ART VL and viremia during cART.

Results

After 32 105 person-years, 3254 of 4931 participants (66%) were classified as suppressed, 438 (9%) were classified as LLV, and 1221 (25%) were classified as nonsuppressed. Neither viremia category nor cumulative viremia during cART had a statistically significant association with cancer. Higher pre-ART VL was associated with cancer (adjusted subhazard ratio, 1.4; 95% confidence interval, 1.0–1.8); this remained statistically significant with viremia during cART in the model. In subanalysis, the association with pre-ART VL was statistically significant for acquired immune deficiency syndrome (AIDS)-defining and infection-related non-AIDS-defining cancer, but not for other malignancies.

Conclusions

In this nationwide cohort, pre-ART VL was an independent predictor of invasive cancer, whereas viremia profile during cART was not associated with cancer incidence.
The Effects of Social Distancing Policies on Non-SARS-CoV-2 Respiratory Pathogens
Authors: Nawrocki Jeff , Olin Katherine , Holdrege Martin C , Hartsell Joel , Meyers Lindsay , Cox Charles , Powell Michaela , Cook Camille V , Jones Jay , Robbins Tom , Hemmert Andrew , Ginocchio Christine C
Published: March 2021

Background

The initial focus of the US public health response to coronavirus disease 2019 (COVID-19) was the implementation of numerous social distancing policies. While COVID-19 was the impetus for imposing these policies, it is not the only respiratory disease affected by their implementation. This study aimed to assess the impact of social distancing policies on non–severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) respiratory pathogens typically circulating across multiple US states.

Methods

Linear mixed-effect models were implemented to explore the effects of 5 social distancing policies on non-SARS-CoV-2 respiratory pathogens across 9 states from January 1 through May 1, 2020. The observed 2020 pathogen detection rates were compared week by week with historical rates to determine when the detection rates were different.

Results

Model results indicate that several social distancing policies were associated with a reduction in total detection rate, by nearly 15%. Policies were associated with decreases in pathogen circulation of human rhinovirus/enterovirus and human metapneumovirus, as well as influenza A, which typically decrease after winter. Parainfluenza viruses failed to circulate at historical levels during the spring. The total detection rate in April 2020 was 35% less than the historical average. Many of the pathogens driving this difference fell below the historical detection rate ranges within 2 weeks of initial policy implementation.

Conclusions

This analysis investigated the effect of multiple social distancing policies implemented to reduce transmission of SARS-CoV-2 on non-SARS-CoV-2 respiratory pathogens. These findings suggest that social distancing policies may be used as an impactful public health tool to reduce communicable respiratory illness.
Calvin and the Efficacy of Infant Baptism
Authors: Bierma Lyle D.
Published: March 2021

Chapter Abstract: This chapter explores the question whether baptism for Calvin functions as a means of knowledge, assurance, and grace not just for adult converts but also for infants, especially since infants are presumably too young to believe. In its examination of the efficacy of infant baptism, the chapter surveys once again the whole of Calvin’s literary corpus, moving through the same stages of his writing career that were laid out in the foregoing chapters. The primary conclusion is that Calvin’s view of infant baptism as an instrument of both knowledge and grace is not as incompatible with his general doctrine of baptismal efficacy as some in the past have suggested. For Calvin, adult convert baptism and pedobaptism are not efficacious in exactly the same way, but the similarities between them are such that the latter can really be viewed as an age-adjusted version of the former.