bluuebunny/crossref_metadata_2025_split huggingface dataset:
Iterative quantum phase estimation on an IBM quantum processor
Authors: Zhuravlev N.A. , Beterov I.I. 
Published: May 2021

Abstract
An elementary algorithm of quantum phase estimation based on the modified Kitaev algorithm is implemented on two qubits of an IBM quantum processor. This algorithm includes adiabatic preparation of the initial state, controlled phase shift with allowance for the results of previous measurements of qubit states, and single measurement of the qubit quantum state in order to obtain each significant bit of the measured phase. Classical error correction is applied to determine the correct sequence of bits, which makes it possible to eliminate the influence of limited accuracy of two-qubit gates.
CXCR4/CXCL12-mediated entrapment of axons at the injury site compromises optic nerve regeneration
Authors: Hilla Alexander M. , Baehr Annemarie , Leibinger Marco , Andreadaki Anastasia , Fischer Dietmar 
Published: May 2021

Significance
Retinal ganglion cell (RGC) axons in the optic nerve convey visual information from the eye to the brain. Injury causes permanent functional loss as axons cannot regenerate. This failure is generally attributed to an insufficient intrinsic regenerative capacity, the extrinsic inhibitory environment, and RGC death. Here, we show that a chemoattractive CXCL12/CXCR4-dependent mechanism entraps growth-stimulated axons at the lesion site, thereby limiting axon extension in the nerve. Accordingly, specific depletion of either CXCR4 or CXCL12 in growth-stimulated RGCs releases entrapped axons and markedly enhances nerve regeneration at long distances. Thus, active CXCL12/CXCR4-mediated attraction to the injury site represents a mechanism preventing central nervous system (CNS) axon regeneration. Moreover, treatments targeting CXCL12/CXCR4 signaling may be promising approaches to improve CNS repair.
DNAM-1 regulates Foxp3 expression in regulatory T cells by interfering with TIGIT under inflammatory conditions
Authors: Sato Kazuki , Yamashita-Kanemaru Yumi , Abe Fumie , Murata Rikito , Nakamura-Shinya Yuho , Kanemaru Kazumasa , Muratani Masafumi , Veillette André , Goto Motohito , Ito Mamoru , Shibuya Akira , Shibuya Kazuko 
Published: May 2021

Significance
Immune tolerance is essential to prevent autoimmune responses, but it often needs to be limited for proper immune response. Regulatory T (Treg) cells play a crucial role in immune tolerance; however, their immune-suppressive function is restricted under inflammatory conditions. Here, we show that the activated immune receptor DNAM-1 limits Treg cell function regardless of DNAM-1–mediated intracellular signaling. We found that DNAM-1 competes with T cell immunoreceptor with Ig and ITIM domains (TIGIT) in binding to a common ligand. DNAM-1 deficiency enhances TIGIT signaling, thus resulting in the Treg cell function’s maintenance under inflammatory conditions. These results suggest that the DNAM-1 and TIGIT balance orchestrate Treg cell function for optimal immune reaction.
Norwegian teacher students’ conceptions of grammar
Authors: Nygård Mari , Brøseth Heidi 
Published: May 2021

Abstract
This paper explores the conceptions of grammar of first-year teacher students (N = 235) in Norway. A conventional content analysis is used to analyse the answers from the first part of a survey exploring the teacher students’ views of grammar through the following questions: Q1. How would you define the term grammar? Q2. Do you think grammar is an important part of Norwegian as a school subject? Q3. Do you feel confident in grammar? The second part of the survey is a grammar knowledge test. The results show that most students define grammar as writing correctly. Many answers also refer to language structure. Among the less frequent definitions are: theoretical knowledge of language structure, precise communication, text, and constituent analysis. Nearly all students report that they consider grammar important. Moreover, most consider their own grammar competence to be relatively good. However, there is a discrepancy between this self-evaluation and the results from the knowledge test, which are quite poor. Our study contributes to the body of research on teacher students’ conception of grammar, which, in a Norwegian context, has been unexplored. We discuss our findings in the light of national and international literature, and we propose plausible contributing factors. We also reflect upon possible consequences for teacher education.
Digital and analog functionality in monolayer AlOx-based memristors with various oxidizer sources
Authors: Zhan Xuepeng , Zhao Guoqing , Yu Xiaolin , Chen Bo , Chen Jiezhi 
Published: May 2021

Abstract
Memristors with the outstanding advantages are beneficial for neuromorphic computing and next-generation storage. Realizing various resistive switching behaviors in monolayer memristors is essential for understanding the device physics and fabricating fully memristive devices. In this paper, a simple and feasible method was proposed to achieve the digital and analog resistive switching in Cu/AlOx/Ag memristors by using ozone and water precursors in atomic layer deposition. According to the characterization results of surface topography, Raman spectrum and electrical measurement, the transition between the abrupt and gradual resistive switching was ascribed to the migration and diffusion of active electrode metal ions in the sparser, rougher and more amorphous AlOx dielectric films. The key features of biological synapses including long-term potentiation/depression, paired-pulse facilitation and learning-experience behaviors were emulated in the analog monolayer memristors. This study makes an important step towards the development of the sophisticated, multi-functional, and large-scale integrated neuromorphic devices and systems.
Shielded high dose rate ocular brachytherapy using Yb-169
Authors: Dupere Justine M , Munro John J , Medich David C 
Published: May 2021

Abstract

Purpose. We propose an approach for treating ocular melanoma using a new type of brachytherapy treatment device. This device couples Yb-169, a middle-energy high dose rate (HDR) brachytherapy source, with a gold shielded ring applicator to better conform radiation exposures to the tumor. In this study, we computationally test the dosimetric output of our proposed shielded ring applicator design using MCNP6 and validate it against an I-125 COMS plaque. Methods. The proposed Yb-169 ring applicator consists of an assembly of discrete sources delivered into an applicator with a conical collimated opening; this opening is tangent to the outside of the source tube. Using MCNP6, we simulated the dosimetric output of a ring of Yb-169 pellets placed within the collimator at various conical diameters and angles to demonstrate the dosimetric distribution for various prescription dose depths and target sizes using static intensity modulation. Results. Using various angles of collimation, the prescription dose was delivered to target apex depths of 3.5–8.0 mm into the eye covering target sizes ranging from 10 to 15 mm in diameter. This proposed device reduced the maximum absorbed dose to critical structures relative to I-125 by 5.2% to the posterior lens, 9.3% to the iris, 13.8% to the optic nerve, and 1.3% to the sclera. Conclusions. This proposed eye plaque design provides a more conformal dose distribution to the ocular tumor while minimizes dose to healthy ocular structures. In addition, the use of a middle-energy HDR brachytherapy source allows the use of a remote afterloader to expose the tumor after the plaque is sutured in place. This system is inherently safer and eliminates dose to the surgeon’s hands.
1-bit reconfigurable transmitarray with low loss and wide bandwidth
Authors: Gao Wen Hua , Chen Mao , Cheng Qiang , Shao Rui Wen , Liang Jing Cheng , Gao Yuan , Cui Tie Jun 
Published: May 2021

Abstract
We present a novel X-band 1-bit reconfigurable transmitarray with excellent polarization conversion. The basic element consists of two layers of metal patterns connected by a metal through-hole and feed structures. The top layer is used to realize a 1-bit phase response by controlling the states of two PIN diodes; the bottom layer is composed of a rectangular patch with a U-slot to realize conversion from linear polarization to cross polarization. The agreement between simulation and measurement results indicates that when the diode states are switched in turn, this unit achieves the phase difference of cross-polarized transmitted waves within 180° ± 15° and high transmittance in a broad band. The scattering patterns demonstrate that beam splitting or multi-beam generation can be achieved by controlling the different coding sequences of each column unit. The element offers low transmission loss, wide bandwidth of 1-bit phase control, and small thickness for easy integration. Thereby, it has numerous potential applications in radar and wireless communications.
Underestimates of methane from intensively raised animals could undermine goals of sustainable development
Authors: Hayek Matthew N , Miller Scot M 
Published: May 2021

Abstract
Greenhouse gas emissions from meat and dairy production are often highly uncertain; these emissions are typically estimated using inventory-based, ‘bottom-up’ models, which contain uncertainties that are difficult to quantify. Modeled emissions estimates can be corroborated using atmospheric measurements—taken above and downwind of animal production regions—to produce ‘top-down’ emissions estimates. Top-down and bottom-up estimates of animal methane show good agreement when considering global emissions. However, in the US, where animal production is predominantly highly intensified with confined feeding operations, animal methane emissions may be 39%–90% higher than bottom-up models predict (expressed as mean differences across studies). Animal emissions may grow in the future as meat and dairy demand increases in developing countries. We examine East and Southeast Asia as a test case, where emissions from increased meat and dairy production are expected to be offset by improved efficiency from intensive methods. We adjust the share of direct emissions projected to come from intensive systems by the intensities derived from US top-down estimates. We find that region-wide emissions from meat and milk production could reach 1.52 (1.41–1.62) GtCO2eq by 2050, an amount 21% (13%–29%) higher than previously predicted. Therefore, intensification may not be as effective in mitigating emissions in developing countries as is commonly assumed.
An Overview of Energy Efficiency and Management; a Case Study of Rural Electrification Agency Building
Authors: Asogwa J C , Fulani F B , Okafor I F 
Published: May 2021

Abstract
Sustainable energy management essentially plays a critical role in the socio-economic activities of man and in the overall productive processes of a nation; consequently, efficient energy utilization and robust management are key parameters that drive energy sustainability. Energy efficiency in this context can be viewed as a function of technological advancement, owing to the fact that what are regarded as efficient products in the seventies and thereafter have in the contemporary time been replaced by the modern efficient ones. In the industries, obsolete equipment is giving way to more efficient and automated ones. Architects too have improved considerably in the design of energy efficient buildings, while in the transport sector, energy efficient automobiles that are eco-friendly are gradually emerging. The work had in general terms discussed energy efficiency and management programmes, and for emphasis, analyzes the results which were obtained during the Walk-through and Diagnostic Energy Audit carried out in the offices of Rural Electrification Agency Building located in FCT. The audit work as presented in this study serves as a measure for exposing all the areas of energy wastages and feasible conservation opportunities in the building complex. Energy Audit Devices deployed in the power sources of the building with behavioral and bioclimatic information as collated produced a reliable data that were used in this study and thus gave broad knowledge of energy efficiency and management measures for achieving sustainability in our national economy.
Biogas Production and Storage from Pig Dung Co-Digested With Pineapple Peel
Authors: Ofomatah A C , Ugwu K E , Ani J U 
Published: May 2021

Abstract
Biomethanation potentials of pig dung co-digested with pineapple peels were investigated. Various blends of pig dung with pineapple peels were charged respectively into 50 kg prototype digesters labeled A to C. Digesters D and E were charged with only pineapple peels and pig dung respectively. Proximate and physico-chemical analyses were determined on the slurry using conventional methods. The wastes were subjected to anaerobic digestion for 35 days at mesophilic temperature range of 25 to 37°C. Relative humidity, ambient temperature, pH, slurry temperature and volume of gas were monitored and recorded on daily basis. Biogas yield increased progressively with higher pig dung blend. Onset of gas flammability was observed on the 5th day for blends of pig dung and pineapple peels, as well as for pineapple peels alone while for pig dung alone, it was observed on the 6th day. This was as a result of lower nitrogen contents of pineapple peels blends compared with that of pig dungs alone, a factor which favours early onset of flammability. Biogas generated from the mixture ranged from 65- 71% CH4, 28 -34% CO2, and traces of hydrogen sulphide and carbon (II) oxide. The biogas was subsequently stored in a gas cylinder using modified pressure system. This study is aimed at converting wastes such as pig dung and pineapple peels to useful energy and storing the gas produced in cylinders for easy accessibility.
Multi-Power Source and Cloud-Backup Enabled Security Framework for Surveillance in Nigeria
Authors: Adebisi J A , Abdulsalam K A , Adams I. O. 
Published: May 2021

Abstract
In Nigeria, power is one of the major problems and this deters the reliability and effectiveness of a video surveillance system as the case may be. Also, as criminal organizations tend to destroy every physical storage after an operation, providing a suitable backup to the cloud is a viable solution to serve as a failsafe plan in case of hardware eventualities. This work focuses on the design and construction of a real-time power and data backup surveillance system for security of lives and properties. Construction of a sufficient power bank backup system was developed in real time with average power outage duration in Nigeria considered. Lithium ion batteries with a cascade connection was used to provide alternate power to the system in a situation of power outage. An Arduino microcontroller controlling relay modules was used to ensure optimum battery life and efficiency and an IP camera was used for surveillance as well as cloud storage. This research was implemented and evaluated to measure the efficiency of the system. The results show that the entire system has the capacity to switch between the direct power source and the alternative power source, it could last for 100- 156hours after full charge in absence of power supply. The data backup was stored to a secured cloud and could only be accessed by authorized users when such is required.
Assessment of wind energy potential of Bauchi in North-East, Nigeria
Authors: Igwebuike M N , Ezeugwu C I 
Published: May 2021

Abstract
Twenty year (1995-2014) monthly mean wind speed and monthly mean wind direction data of Bauchi location were obtained from the Nigeria Meteorological Agency (NIMET) Lagos for the purpose of this study. The data was measured at 3 m height. In order to evaluate wind characteristics, statistical models such as Weibull and Rayleigh distribution were employed in the assessment of wind energy potential. It was observed that Weibull distribution suited the wind speed data more than Rayleigh. Wind rose plot of the monthly wind direction was plotted to determine the best possible direction to mount wind turbine in Bauchi station. Wind characteristics obtained at 3 m height were extrapolated for higher altitudes.
Inspection of Residential Electrical Installations in Bayelsa State: A Review
Authors: Yabefa E. T. , Ainah P. K. 
Published: May 2021

Abstract
The importance of initial verification and the need for periodic inspection and testing of the electrical installation of residential buildings cannot be overemphasized. Fire outbreak in residential buildings is very frequent in Bayelsa State and mostly attributed to electrical fault. The initial verification and periodic inspection and testing are unavoidable electrical procedures for the continuous safe use of any electrical installation. In this paper, a safe working procedure for periodic inspection is presented. The use of the schedule of circuit details, and the electrical danger notification (EDN) form is also presented. The periodic inspection and testing of the electrical installation in residential premises would definitely minimise the frequently witnessed electrical fire in residential buildings in Bayelsa State, and consequently guaranty the safety of both the building and the occupants of the property.
Adoption of appropriate technology for building construction in the tropics; a case of Nigeria
Authors: Nwalusi Dickson M. , Okeke Francis O. 
Published: May 2021

Abstract
Construction technology from the West has played a vital role in building construction in the Tropics. Due to the level of organization, capital and personnel, some cities within Africa can absorb the latest technology faster and better than other cities; thus, their construction development projects using the western borrowed and learned technology has been verbatim and most times, excessively done. This trend, which cuts across many regions of tropical Nigeria leads to the neglect of folk wisdom. Local construction wisdom is usually substituted for new technology without the geography of the area being considered. In 1996, the economic crisis caused the construction business to come to a halt. The cost of oversea technology significantly increased due to the baht flotation policy. Several manufacturers and contractors went bankrupt at that time, including owners of small property in remote parts. While it seems that construction problems from the past are being alleviated, some signs of financial crisis are still evident in recent times. To prevent such future reoccurrence, the study focuses on appropriate construction technology to create social resilience and promote sustainable development. Utilizing literature review research methodology, the concept of appropriate technology is examined, highlighting the appropriate construction technology for the industry in Nigeria’s tropical environment. Photographs of existing building of historic and contemporary architecture were collected and used as a basis for analysis of building construction technology. Benefits and hindrance of appropriate technology are discussed and the research concludes that the only way to achieve economic, social and environmental justice and sustainability is by the adoption of this appropriate technology.
Centralized Electricity Grid and the Rural Economy of Nigeria
Authors: Uzoma C , Atama C , Okpara K , Igwe I , Nnaji M , Adagba C , Onyekaozuru E 
Published: May 2021

Abstract
Electricity is necessary for economic development and no doubt, the best way to ensure adequate supply is through the grid. Nigeria operates a centralized grid system and little is known about how the centralized grid system impacts on the rural economy. This paper examines the impact of the centralized electricity grid on rural electrification and rural economy of Nigeria. Questionnaires were employed to generate data, from 894 respondents in three senatorial districts, in Imo State. Data analysis was conducted using descriptive and inferential (X2 -Chi square) statistics. Result shows that the electricity situation in rural areas is abysmal. Consequently, rural living standard is very low, due to lack of income opportunities. It is concluded that given Nigeria’s large geographical size, the centralized grid rural electrification is fundamentally inadequate. A decentralized electricity structure with emphasis on mini-grids and a priority on localized generation is recommended.
Development of Carbon Fibre Reinforced Natural Rubber Composite for Vibration Isolation
Authors: Eyo-Honesty R. E. , Egbe  , Evudiovo P. 
Published: May 2021

Abstract
This study is based on readily available materials within the locality. The extraction of carbon fibre from periwinkle shell is to reduce the high cost of processing carbon fibre from petroleum pitch and to serve as reinforcement to the natural rubber resin. The fibre was activated using potassium hydroxide (KOH) followed by characterization through XRF, tensile test, hardness and impact test. On forming the composite, the reinforced material was calculated on percentages: 10%, 20% and 30% and added differently to 220grams of natural rubber resin. The samples were then prepared for various tests analysis based on ISO and ASTM standard,(ISO 527 for tensile test, ISO 179 for impact test and ASTM D2240 for hardness test) to determine the composite strength in comparison with the natural rubber for vibration isolation. The basis for this comparison is because natural rubber is widely used as a vibration isolator. The result shows an increased in tensile strength of the composite to 0.20 mega Pascal as against 0.09 mega Pascal of natural rubber resin, good strain rate for improved isolator life and high resistance to thermal expansion
A Grid Tied Short-Through Proof Solar PV Inverter
Authors: Agu M U , Ejiogu E C , Nnadi D B N , Eya C U 
Published: May 2021

Abstract
In this paper, a new grid tied short-through proof solar photovoltaic (PV) inverter that is short-through proof is presented. Detailed presentation of this new solar inverter is preceded by a brief explanation of the generalized solar PV inverter, its types and some representative grid tied solar inverters (mainly micro-inverters) that are currently trending in the solar PV power conversion industry. The merits of each of these briefly explained solar inverter types and power circuits are emphasized. The new grid tied galvanic isolated solar inverter power circuit is then explained in detailed, analyzed and the steady state time varying circuit voltages and currents given. In addition to being short through proof, the new grid tied solar inverter is scalable from solar PV micro-inverter to solar PV central inverter in output power capability unlike the conventional grid-connected single phase inverters.