bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of Ahrar Irrigation Scheme Characteristics Utilizing Remote Sensing Technique
Authors: Shamkhi Mohammed S. , Obeid Zahraa H. , Adbullah Tabarak J.
Published: March 2021

The data of remote sensing techniques is one of the easiest ways to study irrigation projects’ characteristics. Moreover, it is useful when dealing with irrigation management. ArcGIS and ERDAS Imagine software are versatile applications used in this study to provide a suitable framework by visualizing, manipulating, spatial analysis processes, and creating models, especially when dealing with large areas and complex data. This paper aims to calculate the cultivated areas by computing the vegetation indices (VIs) and calculating the land surface temperature (LST), which assists the decision-makers in managing, developing, and evaluating the project. Besides, present other project characteristics, such as soil and land use/ land cover’s physical properties. The use of Landsat 8 data in estimation VIs and LST for Ahrar irrigation project open an opportunity for researchers to apply these values in several types of researches. This paper’s tool produced completely good results of LST, considering that the precision assessment was done with air temperatures. The selected study area was an Ahrar irrigation project located in Iraq’s center within the rickety pier of Mesopotamia’s plain range. The results showed a high decrease in cultivated areas of Ahrar irrigation project during the Summer season in contrast to Winter. This decrease is due to high temperatures, which led to a significant increase in evapotranspiration and water requirement and this was accompanied by a significant decrease in levels of the Tigris river during that season.
Synthesis and Characterisation of Polytetrafluoroethylene Composite for Electrical Insulation and Dielectrics
Authors: Rasheed Laith M. , Mansoor Riyadh
Published: March 2021

This work provides an experimental study to measure the electrical properties of Polytetrafluoroethylene polymer and how it improves through the process of mixing with different volume rates of Poly (methyl methacrylate) PMMA. The relationship of the actual dielectric constant with frequency for pure and dopped models with different concentrations of PMMA (5%, 7%, 10%) and for a range of frequencies ranging between 1-1000 KHz, at the room temperature was investigated. The results show an increase in the dielectric constant of the composites compared to the pure models for all concentrations, which indicates that the polymers interaction gives support to the polytetrafluoroethylene infrastructure. The mixing process, also, leads to an increase in the values the imaginary part of the dielectric constant compared to the pure model, and this is due the significant increase in the number of dipoles resulting from the addition process which in turn led to increase the amount of energy lost due to rotation or friction of the dipoles with each other. This increase, in turn, led to a corresponding rise in the values of the loss tangent tanδ and the AC conductivity of the models. The experimental results show a 90 % increase in the dielectric constant of the composite at 500 KHz compared to the pure Polytetrafluoroethylene, which provide a good electrical insulation material for electronic circuits.
The Influence of Arch Flexibility On The Floor Deck Structural Characteristics For Composite Arch Steel Bridge
Authors: Wali Raneen F. , Muteb Haitham H. , Hadi Abdal-Redha S.
Published: March 2021

This paper presents an optimizing design for the floor deck for the composite arch steel bridge depending on the arch flexibility (the bridge’s main component). The design is based on second-order effects using nonlinear p-delta analysis. Many variables are considered in the parametric study, which is the arch’s in-plane flexibility, the out-of-plane flexibility of the arch, and the number and stiffness of the lateral bracing between the twin arches. The design has been done by graphical design software SAP2000 and based on AISC and AASHTO specifications. A numerical example is studded herein for the new proposed bridge of Batta in Al-Hilla city in Iraq which crossover Al-Hilla river for a width of 108m from bank to bank, the bridge has an overall width of 18 m including two lane-two way of 15.6 m width and walkways of 1.2 m on both sides. This study’s main objectives are the number and size of floor beams, deck thickness, and hence the overall weight of the bridge will be minimum, the goal of design is to select the lightest and most economical and practical composite floor decks. It has been concluded that the deflection decreases with the increase in the number of the floor beam, and the best result was the case of the distance between the floor beam is 1.95 m with a deflection of 71.95 mm, meaning that the flexibility is less as the number of floor beam increases. As for the change of the arch’s cross-section, the best result of the lesser girder deflection was in the case that the arch section with dimensions (0.8 x1.2x0.035) m. This indicates that the greater the moment of inertia, which leads to less deflection for cross over the main girder.
Short-term and Long-term Drought Forecasts in Iraq Using Neural Networks and GIS
Authors: Nasir Hamza Neamah , Ahmed Hamdan Ahmed Naseh
Published: March 2021

Drought is a dangerous phenomenon that affects the general life of the environment. Iraq is one of the countries that is facing drought periodically, especially in the last decades due to the great weather changes in the world including global warming, which resulted in less rainfall below normal levels. Therefore, it must be thought of drought forecasting because it is an important role in the planning and management of the water resources in Iraq. In this Study, Recurrent neural networks (RNN) were used as representing of Artificial Neural Networks (ANNs), which is a non-linear kind of ANNs where the output from it will feedback again as input for the next step. This type of neural network can simulate weather conditions with high precision such as rain, wind, earthquake, drought, and temperature. The model used to forecast droughts is the standardized precipitation index (SPI) series as a drought index in Iraq. The two-time scale which is used in this study, which is SPI 6 which represents short term drought and SPI 24 which represent long term drought. RNN was used to make forecasts for the SPI for the period 2020-2030. The assessment of the work and efficiency of RNN was regressing by (R), mean square error (MSE), and root mean square error (RMSE). Twenty-Four stations were selected to represent all study area (Iraq). Geographic information system (GIS) was used with the aid of Inverse distance weighted (IDW) to represent the forecasted drought for April month from years (2025 and 2030). The results showed that the study region (Iraq) suffered from varied drought levels in different periods ranging from mild to extreme drought, also the study showed improvement by decreasing the drought situation for period 2020-3030, which must be invested well.
Solar energy efficiency in the city of Samawah and its speed in charging off-grid PV system batteries
Authors: Jasim Mohammed Hammoodi , Al-Akoul Karrar A. , Hadi Masar Mohammed
Published: March 2021

The research shows a study of solar energy efficiency in the city of Samawah by using solar cells with some installations to generate electric energy and charge batteries for areas far from electric power plants and areas that are difficult to connect to the national electricity grid (off grid). Solar energy efficiency is calculated based on the average energy consumed within one home during 24 hours without interruption in those areas. Hence, this research focuses on designing a (photovoltaic system) to generate electrical energy consisting of solar cells with a charge regulator with a current inverter with rechargeable storage batteries. This system depends on the average amount of solar radiation falling in those areas and the high temperature of the sun, which is useful for charging and storing batteries faster.
Drop weight impact-water impact relationship of hybrid fiber reinforced concrete
Authors: Ayoob Nadheer S. , Ali Sajjad H. , Abdul Hussein Munther L.
Published: March 2021

The dams’ spillway and its stilling basin are the hydraulic structures that are subjected to very fast water flow, which exposes them to the impact of water and water-dragged materials. To produce an appropriate concrete mixture that is capable to resist such loads, three hybrid fiber-reinforced mixes were prepared using the same materials and a constant total fiber volume fraction of 2.5%, while the fiber hybridization scheme was the only variable. All mixtures had a quantity of 0.5% polypropylene fiber (PP) with length of 18 mm. The first mixture (M1) involved 2% steel fibers with length of 6 mm, while M2 contains 2% of 15 mm steel fibers. A quantity of 1% was added form the two steel fibers for M3. The water-jet impact and drop-weight impact tests were conducted to compare the impact response of the mixtures. The obtained results showed that the abrasion resistance of M2 was higher than that of M1 and M3 by 42 and 21%, respectively. Furthermore, its impact resistance was greater than the average value of that for the other mixes by 43.8%. Finally, the splitting tensile strength can be considered an acceptable scale to describe the abrasion resistance of concrete.
Cold Asphalt Mixtures Characteristics with Cement and Sugar Industry Waste Material as Mineral Filler
Authors: Habeeb Zainab H. , Al-Hdabi Abbas
Published: March 2021

Cold mix asphalt is bituminous material that produced at ambient temperatures. Many advantages can be obtained from cold mix asphalt especially, economic and environmental aspects this come from no need to heat of aggregate and bitumen for purpose the production and laying mix which are remain necessary demand to hot mix asphalt production. However, cold mix asphalt show inferior performance at early life and high porosity. This lab investigation focuses on improving the Cold Bitumen Emulsion Mixtures (CBEMs) containing 2% ordinary Portland cement (OPC) by adding Sugar industry Waste (SW) with different percentages i.e. 2, 4, 6 by total mass of aggregate. The optimum SW content was selected based on Indirect Tensile Strength (ITS) test which was 4%. ITS for the modified mix increased significantly to more than 55% and 32% in comparison with the untreated mixtures and CAEM with 2% OPC, respectively. On the other hand, the results of tests for Marshall Stability (MS), Marshall flow (MF) and index of retained strength (IRS) tests were encouraged. The value of MS and MF for mixtures with 4% SW increased about 140% and 38% respectively while, IRS improved about 45% in comparison with untreated mix. Finally, this research has gave highly improved cold bituminous emulsion mixtures (CBEMs) with SW in addition to environmental and economic benefits.
Experimental Study of Performance of Solar Chimney
Authors: Hassan A A , Ahmed Omer Khalil , Abbas E F
Published: March 2021

In this paper, a practical study was conducted with and without solar panels to show their effect on the performance of the hybrid solar chimney in the city of Kirkuk in Iraq. Six cells were placed between the base of the collector and the glass cover, which gives freedom to the air to move up and down the cells. Also, it is showed that the speed is higher when using PV until it reaches 1.8 m/s while the air leaving the collector and the energy coming out of the chimney and the efficiency of the solar collector and the efficiency of the chimney. The practical results showed that the chimney base is the ideal location for the turbine, as the air velocity is higher than other locations, and the air velocity increases during the day to reach its highest velocities at 1 pm. The maximum kinetic and electrical power and the amount of heat reached 37, 950, and 280 watts, respectively, in February at 1 pm. The results also showed that the location of the photovoltaic cell determines the degree of its temperature, as the solar cells that are in the middle are characterized by high temperature, while the solar cells that are on the ends are at a lower temperature and the solar cell temperature also depends on the surrounding weather conditions. High-efficiency values are observed for all months in the early morning hours due to the solar cells’ low temperature. The highest recorded electrical efficiency values were 17.8% in December.
Influence of Al2O3-Water Nanofluid Coolant on Thermal Performance of Hydrogen PEM Fuel Cell Stacks
Authors: Arear W F , Zeiny A R N , Al-Baghdadi Maher A R Sadiq
Published: March 2021

Hydrogen polymer electrolyte membrane (PEM) fuel cells are renewable and future sustainable power generation systems that operate with zero emissions. Thermal management in fuel cells is still an important issue that must be addressed to extend their life and the possibility of their widespread commercial use. In this research, a simulation model has been developed and validated using MATLAB to investigate the cooling process and its effect on the PEM fuel cells using nanofluids as coolant. Al2O3 nanoparticles have been used due to their thermal characteristics, chemical stability, and cost-effectiveness compared to other nanoparticles. The Al2O3-H2O nanofluid was used with 0.1 to 0.4 vol % concentration. The results showed that employing nanofluids as coolant increases the temperature difference between the coolant outlet and inlet. Nanoparticles concentration increases, the temperature difference increases. Similarly, the nanoparticles concentration increases, both pressure drop across the cooling channel and pumping power increases. Therefore, employing nanofluids in PEM fuel cells seems an impractical choice for the lower temperature difference criterion at a certain pumping power.
An Experimental of Enhancement Heat Exchanger (Shell And Coil) by Different Types of Soil
Authors: Mola Ahmed H , Mutasher Dheya G
Published: March 2021

Soil is one of the sources of energy conservation, accordingly, the present work aims to enhance the thermal storage efficiency and the thermal behavior for a heater system integrated with a helical coil cylindrical system. The helical coil, combined with a tank having a cylindrical shape, has a diameter of (250) mm and a height of (600) mm, placed under the electric heater. In the experimental study, latent heat storage materials (soil, sand and their mixture) having a high specific heat were used to raise the thermal storage. Different cases under a constant temperature hot water (80 0C) from an electric heater with 100 W/m2 were considered. In the first case, the helical coil was immersed in pure sand in the cylindrical tank, and in second case, the helical coil was immersed in compound (50% sand and 50% soil) in the cylindrical tank, while in third case, the helical coil was immersed in pure soil in the cylindrical tank. These cases were verified for both natural and forced convection with different mass flow rates (0.008 and 0.016 kg/sec). For the forced convection with (0.008 kg/sec), the results indicated that the compound (sand and soil) compared with pure sand gave the best thermal storage duration by approximately (36.84%). There was an increase in the outlet water temperature by (8%), and an increase in the mass flow rate to (0.016 kg/min). The duration was (37%), with an increase of (5.84%) in temperature. The increase of the rate of mass flow led to a reduction in time of the outlet water temperature of discharge process.
Mitigation of Membrane Fouling in Waste Water Treatment Plants by Using MBBR & Sponge Membrane Bioreactor (Sponge-MBR)
Authors: Almusawy A M , Al-Anbari R H , Alsalhy Q F
Published: March 2021

A membrane bioreactor system is used to treat domestic wastewater by activated sludge-membrane bioreactor (AS-MBR). Two configurations; moving bed bioreactor, sponge-membrane bio reactor (MBBR & Sponge-MBR) and one nanocomposite membrane have been successfully designed to diminish membrane fouling caused by activated sludge. The classical phase inversion was harnessed to prepare zinc oxide nanoparticles embeded with polyphenyl sulfone nanocomposite membranes ZnO/PPSU using 1.5 g ZnO. Prepared nanocomposite membrane surface was fully characterized by a series of experimental tools, e.g., scanning electron microscopy (SEM), atomic force microscope (AFM), and contact angle (CA), pore size and pore size distribution. The testing procedure was performed through an AS-MBR system as a reference and the results were compared with the configurations obtained from the moving bed (MBBR-MBR) and sponge-MBR, in presence of layer of dense polyurethane sponge (15 x10 x1.5 cm) systems. The fouling reduction of the membrane has improved significantly and thus the overall long-term increased by 145% compared with the control AS-MBR configuration. The experimental results showcased that sponge-MBR were capable of adsorbing activated sludge and other contaminants to minimize the membrane fouling. The sponge-MBR was capable of eliminating nitrogen and phosphorus by 71% and 80%, respectively.
Numerical Simulation of NOx Reduction in a SCR System
Authors: Blinov A S , Malastowski N S , Myagkov L L
Published: March 2021

The stringent limits of emission standards require advanced emission control technologies to be used in modern on and off highway diesel engines. They include both in-cylinder and aftertreatment measures where the latter now have become almost mandatory. Selective catalytic reduction aftertreatment systems are widely used for nitrogen oxide (NOX) conversion in exhaust gases into harmless N2. To reduce time and costs, at the design stage of SCR systems numerical modelling is applied. Mathematical models and methods providing high prediction accuracy with and acceptable level of computational efforts are required. In this work an approach for complete simulation of SCR systems based on the coupling of commercial CFD software with developed multichannel 1D catalyst model is presented. The first one is used to carefully describe processes occurring upstream in the catalytic converter, particularly, during urea water solution injection and flow mixing. As a result, the distributions of flow parameters at catalyst inlet are derived. They are subsequently imported as boundary conditions into a developed multichannel catalyst model that allows one to take them into account when calculating NOx conversion efficiency. Based on the proposed approach a SCR system was simulated. The effect of non-uniform distributions of NH3 concentration and the gas flow velocity at the catalyst inlet on its performance was investigated. It has been shown that they have a great impact on NOX conversion and should be taken into account during the catalyst modelling.
Assessment of the effectiveness of immune neural network
Authors: Zhigalov K , Pokhomchikova E O , Sygotina M V
Published: March 2021

Nowadays the information technology industry is facing a boom in the research of neural networks and related technologies. Networks are used almost everywhere. However, the question of their effectiveness is omitted. Although there is a growing need to move from quantity to quality. The paper considers a variant of the assessment of the effectiveness of the immune neural network with an example.
Reading and processing of analog signals of the software complex “Automated control system for the technological process of the associated production of concentrates of nanostructures MD1 and MD2”
Authors: Kondrat’ev V V , Kolosov A D , Konstantinova M V , Guseva E A
Published: March 2021

In this paper, the main order to automate the control of the technological process of the associated production of concentrates of nanostructures MD1 and MD2 is presented. The algorithm has been developed for processing incoming raw integer data into a real format in the parameter range, which is implemented in software and hardware at the level of the analog input module. The configuration of the algorithm is performed by specifying the input data using the program. The developed algorithms make it possible to implement an effective automated control system for further implementation in production.
Bluetooth based technology for industrial personnel local positioning
Authors: Daudov I M , Orobey M N , Ignatev I V
Published: March 2021

The article presents the implementation of radio beacon functions in Bluetooth technology. The architecture of Bluetooth Low Energy technology is considered. The stages of development of Bluetooth technology from version 4.0 to version 5.2 are given. Advertising channels used by the beacon in the frequency range 2402-2480 MHz are shown. Functions and application of Bluetooth beacons are described.
Principles of organization of technological service systems to ensure their reliability
Authors: Kurochkin V N , Shcherbak N A , Nikitchenko S L
Published: March 2021

The article analyzes technological systems, which are the production basis of organizations that provide services and produce goods, and service subsystems. In order to study the principles and methods of organizing services to ensure the reliability of the technological system, it is necessary to consider four types of technological systems in the agro-industrial complex: technological systems of plant growing, livestock and other agricultural and processing companies; technological systems of plant-growing processes, animal husbandry, processing of vegetable and animal raw materials; technological systems of production units; and technological systems of production units of enterprises. The systematic approach and the monographic method were used; a systematic analysis of the service system was carried out. It was established that the reliability of a technological system can be improved by organizing technical services and relying on the following principles: creation of a parallel system; organization of a reliability management system; the entry of reliability management into the quality management system, risk management and the general structure of enterprise management; analysis of the types and consequences of failures of the technological system; formation of redundancy; state reliability management; optimization of the structure of the subsystem of technical service by modeling their functions and developing tools for providing technical services.
Use of hydraulic drive of sucker-rod pump 120-6-24 in oil and gas industry as an alternative to import substitution of small-sized pumps
Authors: Pogrebnaya I A , Mikhaylova S V
Published: March 2021

The purpose of this article is the research aimed at the improvement of the quality of hydraulic equipment, namely, investigation of the use of hydraulic drive of sucker-rod pump 120-6-24 in oil and gas industry as an alternative to import substitution of small-sized pumps. Nowadays, at the fields of Western Siberia, it is necessary to replace outmoded and worn-out equipment with modern equipment of proven efficiency. To a greater extent, the imported equipment is used in oil industry. For Russian industry import substitution is one of the key tasks. This article considers the task of wells operation with sucker rod pumping units with a surface hydraulic drive with an analysis of its performance. As an alternative to import substitution for small-sized pumps, it is recommended to use innovative equipment - a highly efficient hydraulic drive of a sucker rod pumping unit, which provides a general increase in the efficiency of production processes during operation, increasing oil production during well operation in optimal mode. The use of this drive leads to a decrease in the costs of oil and gas production enterprises by reducing the level of oil deficit and prevents equipment failure in oil fields. The method of oil production with a hydraulic drive hydraulic drive of sucker-rod pump 120-6-24 considered in this article is widely applied in oil and gas industry and became a valid alternative to small-sized pumps.
Developing optoelectronic devices based on AFV properties to control the physical and chemical parameters of oil products
Authors: Rakhimov N , Mukhametshin V Sh , Tyncherov K T
Published: March 2021

This article deals with the development of optical devices based on anomalous photovoltage films. We propose technology for the manufacturing of the optical radiation receiver based on anomalous photovoltage films and optoelectronic sensors to control the physical and chemical parameters of substances and materials. The photoreceiver is a semiconductor device that registers optical radiation and transforms the input optical signal into the output electrical signal of the photodetector. The goal of this work is to facilitate automation and improve labor productivity, as well as miniaturize and improve the quality of oil product analysis and develop a new type of telemetric sensors. The use of generator photoreceivers based on multilayer composition (MLC) as sensors facilitates the fast and accurate oil product measuring and monitoring without contact even for their significant quantities.
Development of digital models and information systems for machine-building enterprises
Authors: Zhigalov K Yu , Daudov Kh A , Gorban A V
Published: March 2021

The paper considers the use of artificial intelligence systems based on neural systems for the automatic construction of a digital model of a machine-building enterprise. For this purpose it is proposed to split the task into two parts: automated design of a digital model of a terrain and three-dimensional terrain objects. Besides, for the automated construction of three-dimensional objects, they must be previously classified. Accordingly, we solve three problems simultaneously. As a result of the described techniques, the Geoinformation System can be used to automate the enterprise plan in real time.
Modern equipment for core sampling while drilling wells in the fields of Tomsk region
Authors: Saveleva N N , Shed S N
Published: March 2021

The drillers face the task to increase the volume of work on exploratory wells to the Lower Cretaceous and Jurassic basement of the fracture intervals in Tomsk region. Paleozoic basement Pz and Kv are the objects with a complex geological structure. The main purpose of each coring sampling from all types of wells is to obtain direct information about the rocks that compose the objects of interest in the fields, which is necessary for the solution of a set of problems of prospecting, exploration and production of hydrocarbons. Research tasks are to identify the features of the development of fracture intervals, the conditions of rock deposition, the type of rocks, the fracture orientation, permeability, porosity, saturation of the pore space with fluid and to forecast promising areas in the Paleozoic basement. The paper describes the work on core sampling in the Paleozoic deposits of Tomsk region. The core sampling equipment and the results obtained at the Severo-Kalinovskoye field are presented. According to the results of the analysis of the cores, the conclusions are drawn about the further stages of drilling for the assessment of the deposits of the Paleozoic basement in Tomsk region.
Adjustment of mud pump parameters by the frequency conversion method
Authors: Suleimanov R I , Khabibullin M Ya , Davydov A Yu , Zaripova L M
Published: March 2021

The article describes the process of adjusting the main parameters of a mud pump by the method of frequency conversion of the current in the electric circuit feeding the pump electric motor. This technical solution creates conditions for more efficient operation of the mud pump, reducing the consumption of electrical energy and increasing the values of operation parameters.
Automation security in a machine-building plant
Authors: Zhigalov K Yu , Guzueva E R , Polovneva S I
Published: March 2021

The operating system is the most important software component of any computer, and therefore, the security of the enterprise information system as a whole depends on the level of implementation of the security policy in a single operating system. In general, Linux operating systems (OS) cannot be considered as a ready-to-use security system. There are many recommendations on improving Linux security, but the authors of these recommendations do not guarantee that their recommendations are sufficient to achieve the required level of system security. This study attempts to systematize available methods for increasing the level of security of application software for Linux-like OSs operating as part of control systems at nuclear power facilities. The required level of security of the entire system can be achieved at the application software level.
‘Magnetic illusion’ can create magnetic fields at a distance
Authors: Allen Michael
Published: March 2021

Physicists in the UK and Spain claim to have found a way to generate and manipulate magnetic fields at a distance, opening the possibility of projecting magnetic fields into inaccessible spaces and the remote cancellation of magnetic sources.
China space mission retrieves lunar samples
Authors: Xin Ling
Published: March 2021

China’s lunar mission Chang’e-5 has successfully retrieved rocks from the Moon – the first attempt to do so for nearly 45 years.
Why breadth beats depth
Authors: Bell Niki
Published: March 2021

Niki Bell says that subject-matter experts do not necessarily make the best teachers
Entrepreneurial Opportunity: Bedrock in Entrepreneurship Research
Authors: Wood Matthew S.
Published: March 2021

Entrepreneurial opportunity represents individuals taking action to introduce new products, services, or ways of organizing. The opportunity concept has interdisciplinary appeal and in the field of entrepreneurship it has been elevated to a defining feature, representing bedrock in entrepreneurship research. Hence, researchers have investigated the emergence and pursuit of opportunity and it has become a topic of lively debate, stemming from competing theoretical approaches designed to represent the phenomenon. Insights gleaned from these discussions and related empirical studies highlight the opportunity concept as a valuable umbrella construct that meaningfully integrates key elements of the entrepreneurial journey. It coherently ties, for example, cognitive attention and belief formation to entrepreneurial action in ways that account for the various elements that influence entrepreneurs’ contemplations of bringing forward something new. This is a generative process that encapsulates entrepreneurs initially coming up with opportunity ideas and then evaluating those ideas for viability. The beliefs generated in the evaluation of opportunity ideas drive entrepreneurial action. There are a host of elements that influence this process and by capturing them, researchers have codified entrepreneurial opportunity as a phenomenon that involves the integration of entrepreneurs’ motivations and goals with the ideas and concepts they generate, and the actions they deploy to bring their concepts to fruition. This understanding presents intriguing arenas for future research, such as work that takes an adaptive and multiple opportunity perspective along with studies that address time and timing as embedded in entrepreneurial opportunity.
Daniel, Margaret
Authors: Logan Sadye L. M.
Published: March 2021

Margaret Daniel (1908–1997) provided outstanding leadership and left an indelible mark on the social work profession in both social work education and practice through her work at the Veterans’ Administration (VA) and through her contributions at the National Institute of Mental Health (NIMH), leading to high standards in social work education.
Mayadas, Nazneen Sada
Authors: Logan Sadye L. M.
Published: March 2021

Nazneen Sada Mayadas (1934–2015), Professor Emerita at the University of Texas at Arlington (UTA), School of Social Work, practiced social work for 50 years. She served with distinction as an international scholar who taught and practiced across national and professional boundaries.
Pugh, William C. “Bill”
Authors: Logan Sadye L. M.
Published: March 2021

William C. “Bill” Pugh (1921–1989) spent his entire professional career working to improve the quality of life of Alabamians. He used his creative social work skills to develop and implement social service programs for many Alabama citizens.
Contamination of Air and Surfaces in Workplaces with SARS-CoV-2 Virus: A Systematic Review
Authors: Cherrie John W , Cherrie Mark P C , Smith Alice , Holmes David , Semple Sean , Steinle Susanne , Macdonald Ewan , Moore Ginny , Loh Miranda
Published: March 2021

Objectives

This systematic review aimed to evaluate the evidence for air and surface contamination of workplace environments with SARS-CoV-2 RNA and the quality of the methods used to identify actions necessary to improve the quality of the data.

Methods

We searched Web of Science and Google Scholar until 24 December 2020 for relevant articles and extracted data on methodology and results.

Results

The vast majority of data come from healthcare settings, with typically around 6% of samples having detectable concentrations of SARS-CoV-2 RNA and almost none of the samples collected had viable virus. There were a wide variety of methods used to measure airborne virus, although surface sampling was generally undertaken using nylon flocked swabs. Overall, the quality of the measurements was poor. Only a small number of studies reported the airborne concentration of SARS-CoV-2 virus RNA, mostly just reporting the detectable concentration values without reference to the detection limit. Imputing the geometric mean air concentration assuming the limit of detection was the lowest reported value, suggests typical concentrations in healthcare settings may be around 0.01 SARS-CoV-2 virus RNA copies m−3. Data on surface virus loading per unit area were mostly unavailable.

Conclusions

The reliability of the reported data is uncertain. The methods used for measuring SARS-CoV-2 and other respiratory viruses in work environments should be standardized to facilitate more consistent interpretation of contamination and to help reliably estimate worker exposure.
Prospective Metamemory Monitoring of Episodic Visual Memory in Community-Dwelling Older Adults with Subjective Cognitive Decline and Mild Cognitive Impairment
Authors: Chi Susan Y , Chua Elizabeth F , Kieschnick Dustin W , Rabin Laura A
Published: March 2021

Objective

Metamemory tasks have been utilized to investigate anosognosia in older adults with dementia, though previous research has not systematically compared memory self-awareness in prodromal dementia groups. This represents an important oversight given that remedial and interventional efforts may be most beneficial before individuals’ transition to clinical dementia. We examine differences in memory self-awareness and memory self-monitoring between cognitively healthy elderly controls and prodromal dementia groups.

Methods

Participants with subjective cognitive decline despite intact objective neuropsychological functioning (SCD; n = 82), amnestic mild cognitive impairment (aMCI; n = 18), nonamnestic mild cognitive impairment (naMCI; n = 38), and normal cognitive functioning (HC; n = 120) were recruited from the Einstein Aging Study for a cross-sectional study. Participants completed an experimental visual memory-based global metamemory prediction task and subjective assessments of memory/cognition and self-awareness.

Results

While, relative to HC, memory self-awareness and memory self-monitoring were preserved for delayed memory performance in SCD and aMCI, these processes were impaired in naMCI. Furthermore, results suggest that poor metamemory accuracy captured by our experimental task can be generalized to everyday memory problems.

Conclusions

Within the framework of the Cognitive Awareness Model, our findings provide preliminary evidence that poor memory self-awareness/self-monitoring in naMCI may reflect an executive or primary anosognosia, with implications for tailored rehabilitative interventions.
Circular DNA enrichment sequencing reveals the viral/satellites genetic diversity associated with the third epidemic of cotton leaf curl disease
Authors: Ahmed Nasim , Amin Imran , Zaidi Syed Shan-e-Ali , Rahman Saleem Ur , Farooq Muhammad , Fauquet Claude Maurice , Mansoor Shahid
Published: March 2021

Cotton leaf curl disease (CLCuD) is the most important limiting factor for cotton production in Pakistan. The CLCuD passed through two major epidemics in this region with distinct begomoviruses/satellites complexes. Since 2015 the disease has again started to appear in epidemic form, causing heavy losses to cotton crop, which we termed as the “third epidemic”. We applied CIDER-seq (Circular DNA Enrichment Sequencing), a recently developed sequencing method for PCR-free virus enrichment to produce a full length read of a single circular viral genome coupled with Sanger sequencing to explore the genetic diversity of the disease complex. We identified a highly recombinant strain of Cotton leaf curl Multan virus and a recently evolved strain of Cotton leaf curl Multan betasatellite that are dominant in all major cotton growing regions in the country. Moreover, we also identified multiple species of alphasatellites with one distinct species, Mesta yellow vein mosaic alphasatellite (MeYVMA) for the first time in cotton. Relative abundance of virus and associated satellites was also determined by real-time quantitative PCR. To the best of our knowledge, this is the first study that determined the CLCuD complex associated with its third epidemic.
Primate Spatial Memory Cells Become Tuned Early and Lose Tuning at Cell-Specific Times
Authors: Papadimitriou Charalampos , Holmes Charles D , Snyder Lawrence H
Published: March 2021

Working memory, the ability to maintain and transform information, is critical for cognition. Spatial working memory is particularly well studied. The premier model for spatial memory is the continuous attractor network, which posits that cells maintain constant activity over memory periods. Alternative models propose complex dynamics that result in a variety of cell activity time courses. We recorded from neurons in the frontal eye fields and dorsolateral prefrontal cortex of 2 macaques during long (5–15 s) memory periods. We found that memory cells turn on early after stimulus presentation, sustain activity for distinct and fixed lengths of time, then turn off and stay off for the remainder of the memory period. These dynamics are more complex than the dynamics of a canonical bump attractor network model (either decaying or nondecaying) but more constrained than the dynamics of fully heterogeneous memory models. We speculate that memory may be supported by multiple attractor networks working in parallel, with each network having its own characteristic mean turn-off time such that mnemonic resources are gradually freed up over time.
SPARC-related modular calcium binding 1 regulates aortic valve calcification by disrupting BMPR-II/p-p38 signalling
Authors: Wang Yaqing , Gu Jia , Du Anning , Zhang Siqi , Deng Mengqing , Zhao Rong , Lu Yan , Ji Yue , Shao Yongfeng , Sun Wei , Kong Xiangqing
Published: March 2021

Aims

Aortic valve calcification is more prevalent in chronic kidney disease accompanied by hypercalcemia. Secreted protein acidic and rich in cysteine (SPARC)-related modular calcium binding 1 (SMOC1) is a regulator of BMP2 signalling, but the role of SMOC1 in aortic valve calcification under different conditions has not been studied. This study aimed to investigate the roles of SMOC1 in aortic valve calcification under normal and high calcium conditions, focusing on the effects on aortic valve interstitial cells (AVICs).

Methods and results

SMOC1 was expressed by aortic valve endothelial cells and secreted into the extracellular matrix in non-calcific valves and downregulated in calcific aortic valves. In vitro studies demonstrated that HUVEC secreted SMOC1 could enter the cytoplasm of AVICs. Overexpression of SMOC1 attenuated warfarin-induced AVIC calcification but promoted high calcium/phosphate or vitamin D-induced AVIC and aortic valve calcification by regulating BMP2 signalling both in vitro and in vivo. Co-immunoprecipitation revealed that SMOC1 binds to BMP receptor II (BMPR-II) and inhibits BMP2-induced phosphorylation of p38 (p-p38) via amino acids 372–383 of its EF-hand calcium-binding domain. Inhibition of p-p38 by the p38 inhibitor SB203580 blocked the effects of SMOC1 on BMP2 signalling and AVIC calcification induced by high calcium/phosphate medium. In high-calcium-treated AVICs, SMOC1 lost its ability to bind to BMPR-II, but not to caveolin-1, promoting p-p38 and cell apoptosis due to increased expression of BMPR-II and enhanced endocytosis.

Conclusions

These observations support that SMOC1 works as a dual-directional modulator of AVIC calcification by regulating p38-dependent BMP2 signalling transduction according to different extracellular calcium concentrations.
Textbook outcome for esophageal cancer surgery: an international consensus-based update of a quality measure
Authors: Kalff Marianne C , van Berge Henegouwen Mark I , Gisbertz Suzanne S
Published: March 2021

Textbook outcome for esophageal cancer surgery is a composite quality measure including 10 short-term surgical outcomes reflecting an uneventful perioperative course. Achieved textbook outcome is associated with improved long-term survival. This study aimed to update the original textbook outcome based on international consensus. Forty-five international expert esophageal cancer surgeons received a personal invitation to evaluate the 10 items in the original textbook outcome for esophageal cancer surgery and to rate 18 additional items divided over seven subcategories for their importance in the updated textbook outcome. Items were included in the updated textbook outcome if ≥80% of the respondents agreed on inclusion. In case multiple items within one subcategory reached ≥80% agreement, only the most inclusive item with the highest agreement rate was included. With a response rate of 80%, 36 expert esophageal cancer surgeons, from 34 hospitals, 16 countries, and 4 continents responded to this international survey. Based on the inclusion criteria, the updated quality indicator ‘textbook outcome for esophageal cancer surgery’ should consist of: tumor-negative resection margins, ≥20 lymph nodes retrieved and examined, no intraoperative complication, no complications Clavien–Dindo ≥III, no ICU/MCU readmission, no readmission related to the surgical procedure, no anastomotic leakage, no hospital stay ≥14 days, and no in-hospital mortality. This study resulted in an international consensus-based update of a quality measure, textbook outcome for esophageal cancer surgery. This updated textbook outcome should be implemented in quality assurance programs for centers performing esophageal cancer surgery, and could standardize quality measures used internationally.
Severe baffle leak after Takeuchi repair successfully treated with coronary bypass and percutaneous baffle closure: a case report
Authors: Naqvi Syed Yaseen , Joynt Michael , Prasad Sunil , Ling Frederick
Published: March 2021

Background

Anomalous left coronary artery from the pulmonary artery is a rare congenital abnormality that requires surgical correction.

Case summary

We describe the case of a 33-year-old female with a history of anomalous left coronary artery of the pulmonary artery who presents with exertional angina. She underwent a Takeuchi repair that was complicated by a baffle leak. She was successfully treated with left internal mammary artery-left anterior descending (LAD) bypass grafting and percutaneous baffle leak closure.

Discussion

The Takeuchi procedure involves the creation of an aortopulmonary window and an intrapulmonary tunnel that ‘baffles’ the aorta to the ostium of the anomalous left coronary artery. The most common late complication of the Takeuchi procedure is the presence of a baffle leak. Percutaneous baffle leak occlusion via vascular plug and coronary bypass of the LAD can successfully treat a baffle leak with excellent short-term follow-up.
Impact of combined α-galactosidase and xylanase enzymes on growth performance, nutrients digestibility, chyme viscosity, and enzymes activity of broilers fed corn–soybean diets
Authors: Liu Xingbo , Xing Kun , Ning Ran , Carné Sergi , Wu Xingqiang , Nie Wei
Published: March 2021

Two experiments were conducted to investigate the effects of a combined α-galactosidase and xylanase preparation on nutrients digestibility and growth performance in broiler chickens. Experiment 1 had 240 broilers allocated to 3 treatments with the dietary supplementation of 0, 300, and 500 g/t of the enzyme combination. Diet and amino acid (AA) digestibility were assessed. Experiment 2 was a 2 × 3 (enzyme × diet) factorial arrangement with 10 replicates of 12 male broilers per replicate. Diets were based on corn–soybean meal (SBM) diet and had 3 nutritional levels (normal, 2% apparent metabolizable energy (AME) and crude protein (CP) reduction, and 4% AME and CP reduction). Each of these diets was fed with or without enzyme supplementation. Growth performance, chyme viscosity, nutrients digestibility, and endogenous enzymes activity were assessed. In experiment 1, enzyme supplementation improved the digestibility of Ca (P = 0.025) and ileal digestibility of total AA, Pro, Alu, Ile, Lys, His, Thr, Glu, Val, Leu, Tyr, and Phe (P < 0.05), and also tended to increase the AME of diets (P < 0.10). In experiment 2, broilers fed the corn–SBM diet with 4% nutrient reduction had better growth performance (P < 0.05), jejunal digesta viscosity at 42 d (P < 0.01), and lower digestibility of gross energy (GE; P < 0.05) when compared with those fed the normal nutrient diet. Enzyme inclusion increased digestibility of CP (P = 0.044), GE (P = 0.009), raffinose (P < 0.001) and stachyose (P < 0.001), improved average daily gain (P = 0.031), and reduced jejunal digesta viscosity at 42 d (P = 0.011). Besides, similar improvements trend in amylase, trypsin, sucrase, and maltase activity with enzyme inclusion were observed as with energy. These data support that the enzyme supplementation increased nutrients and ileal AA digestibility, improved performance and endogenous enzymes activity.
Utility of Antigen-Based Rapid Diagnostic Test for Detection of SARS-CoV-2 Virus in Routine Hospital Settings
Authors: Thakur Preeti , Saxena Sonal , Manchanda Vikas , Rana Neha , Goel Ruchi , Arora Ritu
Published: March 2021

Objective

This study aims to evaluate the performance of an antigen-based rapid diagnostic test (RDT) for the detection of the SARS-CoV-2 virus.

Methods

A cross-sectional study was conducted on 677 patients. Two nasopharyngeal swabs and 1 oropharyngeal swab were collected from patients. The RDT was performed onsite by a commercially available immune-chromatographic assay on the nasopharyngeal swab. The nasopharyngeal and oropharyngeal swabs were examined for SARS-CoV-2 RNA by real-time reverse-transcription quantitative polymerase chain reaction (RT-qPCR) assay.

Results

The overall sensitivity of the SARS-CoV-2 RDT was 34.5% and the specificity was 99.8%. The positive predictive value and negative predictive value of the test were 96.6% and 91.5%, respectively. The detection rate of RDT in RT-qPCR positive results was high (45%) for cycle threshold values <25.

Conclusion

The utility of RDT is in diagnosing symptomatic patients and may not be particularly suited as a screening tool for patients with low viral load. The low sensitivity of RDT does not qualify its use as a single test in patients who test negative; RT-qPCR continues to be the gold standard test.