bluuebunny/crossref_metadata_2025 huggingface dataset:
Four-wave mixing and coherently coupled Schrödinger equations: Cascading processes and Fermi–Pasta–Ulam–Tsingou recurrence
Authors: Yin H. M. , Pan Q. , Chow K. W.
Published: August 2021

Modulation instability, breather formation, and the Fermi–Pasta–Ulam–Tsingou recurrence (FPUT) phenomena are studied in this article. Physically, such nonlinear systems arise when the medium is slightly anisotropic, e.g., optical fibers with weak birefringence where the slowly varying pulse envelopes are governed by these coherently coupled Schrödinger equations. The Darboux transformation is used to calculate a class of breathers where the carrier envelope depends on the transverse coordinate of the Schrödinger equations. A “cascading mechanism” is utilized to elucidate the initial stages of FPUT. More precisely, higher order nonlinear terms that are exponentially small initially can grow rapidly. A breather is formed when the linear mode and higher order ones attain roughly the same magnitude. The conditions for generating various breathers and connections with modulation instability are elucidated. The growth phase then subsides and the cycle is repeated, leading to FPUT. Unequal initial conditions for the two waveguides produce symmetry breaking, with “eye-shaped” breathers in one waveguide and “four-petal” modes in the other. An analytical formula for the time or distance of breather formation for a two-waveguide system is proposed, based on the disturbance amplitude and instability growth rate. Excellent agreement with numerical simulations is achieved. Furthermore, the roles of modulation instability for FPUT are elucidated with illustrative case studies. In particular, depending on whether the second harmonic falls within the unstable band, FPUT patterns with one single or two distinct wavelength(s) are observed. For applications to temporal optical waveguides, the present formulation can predict the distance along a weakly birefringent fiber needed to observe FPUT.
Thermal laser evaporation for the growth of oxide films
Authors: Kim Dong Yeong , Mannhart Jochen , Braun Wolfgang
Published: August 2021

Thermal laser evaporation (TLE) is a particularly promising technique for the growth of metal films. Here, we demonstrate that TLE is also suitable for the growth of amorphous and polycrystalline oxide films. We report on a spectrum of binary oxide films that have been deposited by laser-induced evaporation of elemental metal sources in oxygen–ozone atmospheres. The oxide deposition by TLE is accompanied by an oxidation of the elemental metal source, which systematically affects the source molecular flux. Fifteen elemental metals were successfully used as sources for oxide films grown on unheated substrates, employing one and the same laser optic. The source materials ranged from refractory metals with low vapor pressures, such as Hf, Mo, and Ru, to Zn, which readily sublimates at low temperatures. These results reveal that TLE is also well suited for the growth of ultraclean oxide films.
Formation of thermally grown SiO2/GaN interface
Authors: Akazawa Masamichi , Kitawaki Yuya
Published: August 2021

An attempt was made to form a thermally grown SiO2/GaN interface. A Si layer deposited on the c-plane GaN surface was oxidized in an O2 atmosphere to form a SiO2 layer. The formation of SiO2 with a bandgap of 8.6 eV was confirmed by x-ray photoelectron spectroscopy. Metal–oxide–semiconductor diodes were fabricated and tested to characterize the interface by electrical measurements. The capacitance–voltage (C–V) characteristics measured at 1 MHz showed that a longer oxidation time resulted in a steeper slope. However, it was unavoidable that a bump in a C–V curve appeared after a long oxidation time. The electron trap distributions derived from C–V curves exhibited a discrete-level trap at 0.7 eV from the conduction band edge. This discrete-level trap was an acceptor-like trap that can be assigned to a Ga vacancy. An insufficient oxidation led to a high leakage current owing to the asperities of the residual polycrystalline Si layer. Although the leakage current was improved by extending the oxidation time, an excessively long oxidation time resulted in a slight increase in the leakage current. We cannot deny the possibility of the diffusion of Ga atoms into SiO2 during oxidation. Moreover, the cross-sectional transmission electron microscopy and energy-dispersive x-ray spectroscopy of a sample formed with an excessively long oxidation time indicated the formation of a Ga oxide interlayer without a severe disorder. Most possibly, the formation of the Ga oxide interlayer by excess oxidation improved the interface properties.
Large Hall and Nernst responses from thermally induced spin chirality in a spin-trimer ferromagnet
Authors: Kolincio Kamil K. , Hirschberger Max , Masell Jan , Gao Shang , Kikkawa Akiko , Taguchi Yasujiro , Arima Taka-hisa , Nagaosa Naoto , Tokura Yoshinori
Published: August 2021

Significance

The scalar spin chirality (SSC) produced by noncoplanar spins is a cornerstone of the foundation of skyrmionics and the physics of geometrically frustrated magnets; this quantity translates the topology of the magnetic structure to the language of directly measurable responses in transport properties. In this work, we not only report the gigantic Hall and Nernst effects emerging from thermally induced SSC in a conducting ferromagnet, but also find arguments for the relevance of the momentum space description of the generated Berry phase. Furthermore, we demonstrate that the idea of fluctuating SSC is not limited to magnets with conduction electrons strongly Hund’s-rule–coupled to local magnetic moments but is valid for a broader group of itinerant magnets with triangular-like lattice geometry.
Hydrogen bonding rearrangement by a mitochondrial disease mutation in cytochrome
bc
1
perturbs heme
b
H
redox potential and spin state
Authors: Kuleta Patryk , Lasham Jonathan , Sarewicz Marcin , Ekiert Iwona , Sharma Vivek , Ekiert Robert , Osyczka Artur
Published: August 2021

Significance

To perform their specific electron-transfer relay functions, hemes commonly adopt low spin states with fine-tuned redox potentials. Understanding molecular elements controlling these properties is crucial for the description of natural proteins and engineering redox-active systems. We describe unusual effects of mitochondrial disease-related mutation in cytochrome
bc
1
, based on which we identify a dual role of hydrogen bonding to the propionate group of heme
b
H
. We observe that stabilization of the hydrogen bond in mutant enhances the redox potential but destabilizes the low spin state of oxidized heme. This demonstrates a critical role of the hydrogen bonding, and heme-protein interactions in general, to secure a suitable redox potential and spin state, a notion that might be universal for other heme proteins.
A physical model of mantis shrimp for exploring the dynamics of ultrafast systems
Authors: Steinhardt Emma , Hyun Nak-seung P. , Koh Je-sung , Freeburn Gregory , Rosen Michelle H. , Temel Fatma Zeynep , Patek S. N. , Wood Robert J.
Published: August 2021

Significance

Many small organisms produce ultrafast movements by storing elastic energy and mediating its storage and rapid release through a latching mechanism. The mantis shrimp in particular imparts extreme accelerations on rotating appendages to strike their prey. Biologists have hypothesized, but not tested, that there exists a geometric latching mechanism which mediates the actuation of the appendage. Inspired by the anatomy of the mantis shrimp striking appendage, we develop a centimeter-scale robot which emulates the linkage dynamics in the mantis shrimp and study how the underlying geometric latch is able to control rapid striking motions. Our physical and analytical models could also be extended to other behaviors such as throwing or jumping in which high power over short duration is required.
Emergent electromagnetic induction beyond room temperature
Authors: Kitaori Aki , Kanazawa Naoya , Yokouchi Tomoyuki , Kagawa Fumitaka , Nagaosa Naoto , Tokura Yoshinori
Published: August 2021

Significance

Emergent inductors that utilize emergent electric fields generated by the current-induced motion of spiral spin textures have the potential to realize dramatic miniaturization of inductance elements. By using YMn
6
Sn
6
, which has been attracting attention as a kagome lattice magnetic material in recent years, we have realized the room-temperature operation of emergent inductors. This micron-scale emergent inductor device shows not only an inductance as large as a commercially available product but also a sign change of inductance, which is a previously undescribed phenomenon.
Multidimensional four-wave mixing signals detected by quantum squeezed light
Authors: Dorfman Konstantin , Liu Shengshuai , Lou Yanbo , Wei Tianxiang , Jing Jietai , Schlawin Frank , Mukamel Shaul
Published: August 2021

Significance

Quantum light and its statistics provide powerful tools for the study of properties of matter that are difficult to retrieve with classical light. Novel spectroscopic and sensing techniques based on quantum light sources can reveal information about complex material systems that is not accessible by varying the frequencies or time delays of classical light pulses. Here, based on a four-wave mixing process, we report an experimental study of the 2D quantum noise spectra of two-beam intensity difference squeezing. External noise erodes the resolution of classical measurements, while quantum signals remain intact. Our results pave the way for exploiting quantum correlations of squeezed light for spectroscopic applications.
Hierarchical self-assembly of polydisperse colloidal bananas into a two-dimensional vortex phase
Authors: Fernández-Rico Carla , Dullens Roel P. A.
Published: August 2021

Significance

Hierarchically self-assembled materials—structures with order at multiple length scales—can be found everywhere. Examples range from collagen structures in human bones to engineered photonic materials. These structures usually assemble from monodisperse microscopic building blocks that interact via complex directional interactions. In this work, we show that hierarchical materials can, in fact, also be assembled from polydisperse building blocks and by entropic interactions alone. Our simple yet powerful assembly mechanism opens up avenues toward rationally exploiting the often undesired polydispersity of colloidal building blocks for programming entropy-driven self-assembly of hierarchical materials.
Genetic screen for suppression of transcriptional interference identifies a gain-of-function mutation in Pol2 termination factor Seb1
Authors: Schwer Beate , Garg Angad , Jacewicz Agata , Shuman Stewart
Published: August 2021

Significance

Long noncoding RNA (lncRNA) transcriptional interference with the synthesis of downstream messenger RNAs underlies regulated biological responses of yeast cells to nutrient availability. For example, expression of the phosphate (
PHO
) regulon in phosphate-replete fission yeast cells is tunable by genetic manipulations that favor or disfavor precocious lncRNA 3′-processing/termination. A forward genetic screen for relief of lncRNA interference with
pho1
expression uncovered a mutation G476S in the RNA-binding domain of essential termination factor Seb1 that evokes precocious lncRNA termination in response to 5′-proximal poly(A) sites in a manner dependent on cleavage and polyadenylation factor CPF, termination factor Rhn1, and inositol pyrophosphate synthesis. Multiple lines of evidence point to Seb1-G476S as a unique gain-of-function mutation in a Pol2 transcription termination factor.
Agroecosystems' resilience and social-ecological vulnerability index to climate change in Kilimanjaro, Tanzania.
Authors: Shirima Kelvine C. , Mung'ong'o Claude G.
Published: August 2021

The concept of resilience has gained momentum during the current climate change era. Resilience is said to be the measure of the amount of change the system can undergo while still retaining the same controls on function and structure. Taking into account the effects of changing climate, the term resilience has been used to assess the vulnerability of social-ecological systems. Most agroecosystem studies have focused on dryland ecosystems and this prompted the need to shift concern on to mountainous ecosystems whose susceptibility to climate change is not adequately addressed. This chapter assesses the resilience of maize-coffee-banana agroecosystems on the southern slope of Mount Kilimanjaro in Tanzania. Also, it assesses agronomic practices and the social-economic status of farmers and computes a social-ecological vulnerability index for the ecosystem. The study depicts variation of agronomic practices with altitude due to microclimatic differences, terrain and soil characteristics that determine the type of crops and their farming system which have both positive and negative implications. Climatic shocks (e.g. drought frequency, floods and below average rains) were found to have an impact on agricultural yield. Social-economic indicators (e.g. the number of household dependants, social safety nets, off-farm contribution, possession of land title, usage of wood for cooking energy and access to extension services) have also shown a significant influence on household vulnerability to changing climate which may later affect the agroecosystem productivity as these parameters are associated with the natural environment. Indicators chosen for the vulnerability index depict slight variations of vulnerability altitude wise, except for the mid-lower zone which appears to be more vulnerable.
A comparative cost-benefit analysis of mobile and sedentary pastoral production systems in selected villages in Northern Tanzania.
Authors: Yamat Lucas E. , Mung'ong'o Claude G.
Published: August 2021

Despite a growing body of evidence that highlights the economic, social and environmental benefits of mobile pastoralism, few governments are ready to tolerate mobility and many policy makers promote knowingly or inadvertently the policies of sedentarization. This production system seems not to be clearly understood by many and has been characterized as backward, environmentally destructive and economically unsustainable; and the view is that it should be replaced with more sedentary forms of livestock production or other beneficial land uses. The overriding question is whether sedentary livestock keeping is more productive and utilizes fewer resources and less space than the mobile pastoral system. This study carried out a comparative cost-benefit analysis of the two production systems in selected villages of Kiteto and Karatu districts. The aim was to come up with credible data to test this hypothesis. Two alternatives were compared in terms of their net present value (NPV) to test a null hypothesis. The alternative with an NPV greater than zero or higher than its alternative was accepted to be more viable compared with the one with an NPV less than zero or less than its alternative. Whenever the NPV of the sedentary production system in the analysis was shown to be greater than zero and/or greater than the NPV of the mobile pastoral production system the null hypothesis was accepted and vice versa. The study was conducted in Makame village of Kiteto District and Dofa village of Karatu District. Makame village represents a mobile pastoral production system while Dofa village represents a sedentary production system. The study employed a quantitative approach using a household survey in the two villages. The comparative cost-benefit analysis was carried out using monetary values derived from the livestock unit statistical approach. The findings have revealed that the average cost of maintaining a mobile pastoral and sedentary production systems are TSh90,096,333 and TSh112,295,200, respectively. The cost-benefit ratios are 1:0.5 for a mobile pastoral production system and 1:0.25 for the sedentary one.
Locally based responses to impacts of climate change in pastoral landscapes of Northern Tanzania.
Authors: Mabhuye Edmund B. , Yanda Pius Z.
Published: August 2021

The impacts of climate change and variability have manifested themselves throughout the world, but considerable temporal and spatial variations exist across various places and countries. Given the variation in vulnerability, this study was undertaken in pastoral landscapes in northern Tanzania to assess the impacts of climate change, adaptation strategies and their implications to communities' livelihoods and ecosystem integrity. It examined: (i) climate trends and associated impacts on communities' livelihood options; (ii) climate change coping and adaptation strategies adopted by selected communities to reduce the severity of climate change impacts; and (iii) the challenges associated with climate change adaptation strategies in the pastoral landscape. Primary data were collected using household surveys, interviews with key informants, focus group discussions, direct field observation using transect walks and institutional analysis. Secondary data were obtained through documentary review and theme-content analysis. Results indicate that there are slight increases in temperature and wind speed as well as decreasing trends and erratic patterns of rainfall which cause drought and extended dry spells. Fluctuation in temperature and rainfall patterns affects livestock keeping through recurrent drought that has negative implications on pasture and water availability. Communities are responding to the changes through traditional response mechanisms and have embraced a few new adaptation strategies against these climate extremes, particularly drought. Generally, strategies for adaptation are likely to be successful in the near future, subject to review and harmonization of policies, institutional and legal frameworks to harness existing opportunities for management of natural resources for sustainable development and build the long-term balance between ecosystem integrity and human needs.
The role of ecosystem services in enhancing climate change resilience of local communities: the case of Ngarambe-Tapika Wildlife Management Area, Rufiji district, Tanzania.
Authors: Katondo Richard J.M. , Nyomora Agnes M.S.
Published: August 2021

This study examined the role of ecosystem services in enhancing climate change resilience of local communities in Ngarambe-Tapika Wildlife Management Area (WMA). The study aimed to identify forms of ecosystem services that can be gained from conservation of a WMA in relation to climate change adaptation. The design for this study adopted both a quantitative and a qualitative research approach. The study was undertaken in Ngarambe-Tapika WMA located between latitude 39° S and 39°30' S and between longitude 12°30' E and 13° E. It is located alongside the north-eastern border of the Selous Game Reserve. The area is also the home of local people whose lifestyles and livelihoods are intricately tied to the biological diversity and the functioning of this natural system. Purposive sampling was employed in selecting respondents for the household questionnaire, focus group discussions and key informant interviews. This study found that income obtained from Ngarambe-Tapika ecosystems by the communities were invested in material welfare and livelihoods that enhance resilience to climate change, primarily social services (54.9%) such as construction of houses, dispensaries and rehabilitation of the primary schools, and some of the money was spent on electricity provision for the community and energy for light and water pumps. Other benefits included employment (16.5%), protection from dangerous and problematic wildlife (14.3%) and petty business (14.3%). Generally, in Ngarambe-Tapika WMA there is a need to emphasize conservation awareness and extension programmes which advocate sustainable utilization of wildlife resources, and adopt an integrated approach of climate-smart agriculture to address the challenges related to food insecurity and climate change and variability. The latter would enable increased agricultural productivity to support equitable increases in farm incomes, improve food security and build resilience of agricultural and food security systems to adapt to climate change and variability.
Effectiveness of existing climate smart agricultural practices in Tehuledere district, north-eastern Ethiopia.
Authors: Wassie Adera S. , Pauline Noah M.
Published: August 2021

This study sought to understand the effectiveness of existing climate smart agricultural (CSA) practices used by smallholder farmers in Tehuledere District, north-eastern Ethiopia, using empirical data collected over 3 months in 2016. Both qualitative and quantitative data were collected from primary and secondary sources, including historical climatic records and perceptions, indicatiors of climate change, impacts and responses. The study employed focus group discussions and a household questionnaire survey during data collection. Findings reveal that the majority of participants are aware of climate change and variability. The indicators of climate change include drought, off-season rainfall, too little and/or too much rainfall, and high temperature. The impact of climate variability observed by participants include: (i) decreasing crop yields and livestock production; (ii) increasing pests and disease; and (iii) decreasing water quantity and quality. The adaptation measures embraced to mitigate negative climate change effects include: (i) changing crop varieties; (ii) integrating livestock and crop production; and (iii) soil and water conservation practices. As far as CSA practices were found to be viable and effective response measures, support from innovative polices and strategies should be emphasized so as to address the barriers and bring about widespread adoption.
Community livelihoods and ecosystem integrity in makere forest reserve, western Tanzania.
Authors: Yanda Pius Z. , Mabhuye Edmund B. , Mwajombe Anselm R. , Johnson Namkunda
Published: August 2021

Wealth creation and poverty alleviation processes in the forest-bounded areas entail the use of such forests to a greater extent. Studies elsewhere show that there is often a tendency to use such forests until they are depleted before technology comes in to improve livelihoods. In this chapter, we examine community livelihoods in relation to ecosystem integrity for communities surrounding the Makere Forest Reserve, particularly socio-economic characteristics of communities, their links to forest utilization and implications for ecosystem integrity. We used mixed methods to collect data: (i) a household questionnaire; (ii) focus group discussions; (iii) key informant interviews; and (iv) a literature review, backed up with satellite imagery. Quantitative and qualitative data collected were subjected to statistical and non-statistical tests, respectively, with the use of Statistical Package for Social Sciences (SPSS) computer software for quantitative data analysis. Livelihood activities in the area include shifting cultivation, livestock keeping, firewood fetching, charcoal making, harvesting timber and illegal logging. The motive for such forest exploitation is both for meeting household needs as well as for wealth accumulation. Forest users take part in such activities regardless of the distance they have to travel from their villages to come to the forest areas. We found education is an integral part of wealth status, but had nothing to do in terms of improving livelihood activities for ecosystem integrity. The absence of livelihood diversification of farm-related activities penetrates into weak forest governance strategies resulting in proliferation of deforestation and forest degradation. To maintain forest integrity, integrated approaches in forest management and alternative livelihood activities are needed such as beekeeping, fishing and modernized livestock keeping. These activities have the potential to increase household food and income and alleviate poverty levels without compromising ecosystem integrity.
Population ecology.
Authors: Rees Paul A.
Published: August 2021

This chapter contains questions about the growth, control, regulation and analysis of biological populations.
Answers.
Authors: Rees Paul A.
Published: August 2021

A multiple choice question has a stem (the 'question'), a key (the 'answer') and a number of distracters (wrong answers intended to distract the student from the key). This part of the book contains the key to each question along with a brief explanation of why this is correct and, in some cases, what the distracters mean. The questions are grouped into 10 major topic areas: (1) The history and foundations of ecology, (2) Abiotic factors and environmental monitoring, (3) Taxonomy and biodiversity, (4) Energy flow and production ecology, (5) Nutrient and material cycles, (6) Ecophysiology, (7) Population ecology, (8) Community ecology and species interactions, (9) Ecological genetics and evolution, (10) Ecological methods and statistics.
Enhanced cGAS-STING–dependent interferon signaling associated with mutations in ATAD3A
Authors: Lepelley Alice , Della Mina Erika , Van Nieuwenhove Erika , Waumans Lise , Fraitag Sylvie , Rice Gillian I. , Dhir Ashish , Frémond Marie-Louise , Rodero Mathieu P. , Seabra Luis , Carter Edwin , Bodemer Christine , Buhas Daniela , Callewaert Bert , de Lonlay Pascale , De Somer Lien , Dyment David A. , Faes Fran , Grove Lucy , Holden Simon , Hully Marie , Kurian Manju A. , McMillan Hugh J. , Suetens Kristin , Tyynismaa Henna , Chhun Stéphanie , Wai Timothy , Wouters Carine , Bader-Meunier Brigitte , Crow Yanick J.
Published: August 2021

Mitochondrial DNA (mtDNA) has been suggested to drive immune system activation, but the induction of interferon signaling by mtDNA has not been demonstrated in a Mendelian mitochondrial disease. We initially ascertained two patients, one with a purely neurological phenotype and one with features suggestive of systemic sclerosis in a syndromic context, and found them both to demonstrate enhanced interferon-stimulated gene (ISG) expression in blood. We determined each to harbor a previously described de novo dominant-negative heterozygous mutation in ATAD3A, encoding ATPase family AAA domain–containing protein 3A (ATAD3A). We identified five further patients with mutations in ATAD3A and recorded up-regulated ISG expression and interferon α protein in four of them. Knockdown of ATAD3A in THP-1 cells resulted in increased interferon signaling, mediated by cyclic GMP-AMP synthase (cGAS) and stimulator of interferon genes (STING). Enhanced interferon signaling was abrogated in THP-1 cells and patient fibroblasts depleted of mtDNA. Thus, mutations in the mitochondrial membrane protein ATAD3A define a novel type I interferonopathy.
Frequency synchronization of single flux quantum oscillators
Authors: Yamanashi Yuki , Kinoshita Ryo , Yoshikawa Nobuyuki
Published: August 2021

We demonstrate the frequency synchronization of multiple single-flux quantum (SFQ) oscillators with different oscillation frequencies. To synchronize these SFQ oscillators, a common constant bias current is supplied to the SFQ oscillators without any bias resistors. When an SFQ oscillator oscillates at a frequency of f, the average voltage across the Josephson junction comprising the SFQ oscillator is

f

Φ

0

, where

Φ

0

is the flux quantum in the superconductor. The bias currents supplied to the SFQ oscillators are redistributed to eliminate the average voltage difference output from the SFQ oscillators. As a result, the oscillation frequencies of all the SFQ oscillators are synchronized. Simulation results indicate that SFQ oscillators with an oscillation frequency difference of more than 50 GHz can be synchronized. We experimentally demonstrate the frequency synchronization of two SFQ oscillators composed of circular Josephson transmission lines. Frequency synchronization is expected to contribute toward the development of a low-power stable clock source stabilizing SFQ circuit operation.
The influence of the architecture form in the performance analysis of a passive house in Moldavia
Authors: Cojocaru A , Isopescu D N
Published: August 2021

Over time, a building’s energy consumption in the use phase was not decisive in the design process. However, in recent years, energy efficiency and energy autonomy have become a defining criteria in buildings’ performance. In 2020, residential buildings became the space for rest, recreation, personal activities, but also for professional activities. Thus, it is essential to ensure optimal temperature, air, humidity and psychological comfort due to architectural quality. The passive house concept sets the maximum allowable energy consumption to heat the building and limit the total primary energy consumption. Passive houses improve energy-efficient buildings by ensuring a comfortable indoor environment in all seasons without requiring a conventional heat distribution system. Based on local characteristics, creating and analysing model study cases is important and could solve cities’ fast development. The shape of a building influences the solar input and the total energy consumption through the total surface exposed to the outside and subject to heat loss. In order to gain knowledge about the influence of the buildings’ form on energy balance, this paper presents a case study of simple shape buildings with numerical analysis according to the passive house principles in the Moldavia area of Romania. The case study of a parallelepiped model with various dimensions, varying aspect ratio and storey, was made with the planning tool Passive House Planning Package. The conclusions suggest further case studies with various roof shapes and windows’ areas.
Project management software in Ukraine
Authors: Azhaman I , Petryshchenko N , Hronska M , Pandas A , Pushchina N
Published: August 2021

Modern consumers are interested in receiving goods within a specified time frame, of the required quality and quantity. Such requirements apply to all goods and services, including those in the construction industry. Features of the construction industry are due to a variety of technologies, materials, equipment used for the construction of facilities. This justifies the need to implement automation tools for planning processes, determining the volume and delivery schedule of production stocks, using labour resources, forming a financing schedule, identifying risks affecting processes and approaches to minimizing them. To solve such problems, special attention in modern conditions is paid to project management in construction and its software. A project is understood as a process which is a set of sequential actions, the implementation of which contributes to the achievement of the set goal. The project is characterized by limitations in terms of time, cost and resources used. In project management, software products such as Primavera Systems, Inc (Oracle), Spider Project, Microsoft Office Project, YouControl. It is their use, advantages and disadvantages that are discussed in the paper. Particular attention is paid to the Microsoft Office Project software product, which has the following advantages: user-friendly interface and ease of use, flexibility of adaptation to user needs, clear and convenient analytical charts and the ability to manage them, availability of support that allows you to quickly master and use the software product, availability of reference materials.
The concept of an automatic system for preliminary entry of hazardous facility into emergency mode with an approaching earthquake
Authors: Zhukovsky V , Rusu I , Zavoloka M , Grynyova I
Published: August 2021

The article discusses the concept of introducing an automatic system for preliminary input of hazardous facilities into emergency mode in the event of an approaching earthquake, developed at the South Ukrainian National Pedagogical University named after K. D. Ushinsky. Theoretical prerequisites for the study of heterogeneities, using a passive method based on the location of secondary waves reflected from the inhomogeneities under the basements and foundations of buildings of already operated building structures, were taken as the basis of the proposed system. Due to the finite speed of propagation of seismic waves and having a sensor in the focus of an earthquake, it is possible for distant objects to learn about an impending disaster in a few tens of seconds. The effective use of the time window from the focus of the earthquake to hazardous facilities requires the development of: measuring equipment, data transmission systems, automatic event recognition, elements for automating the process of putting hazardous objects into emergency mode- all this is the goal and objectives of this article.
Performance analysis for an improved strategy in optimal control of civil engineering structures
Authors: Păuleț-Crăiniceanu F , Florea V , Pastia C , Luca S G , Roșca O V
Published: August 2021

Civil Engineering structures are already an important part in the Smart Cities concept. In connection to this, integration of new technologies is under way in the field of Structural Engineering as in all Civil and Buildings/Bridges Engineering. One of the main goals is to protect structures from possible harm from earthquakes. In order to achieve this goal, Optimal Active Control has been proposed and used with a high degree of success. However, the application strategies are continuously improving. A strategy consisting in simplifying the Optimal Active control for full states has been proposed by the authors and relatively recently modified for an increased efficiency. That was a theoretical research taking into account the possibility to reduce the order of magnitude of matrices involved in computations. The present paper is assuming the previous theoretical result and simulates its application to the structural model of a ground floor plus ten floors building specially designed for this purpose. The reinforced concrete frame building’s behaviour is analysed under seismic actions. Efficiency and the control strategy are observed in different scenarios. The structural response is revealing that the new strategy is working faster in limiting the effects of earthquake input. In addition, the reduced computational time leads to a faster control and smaller phase-shift in practical use.
Seismic vulnerability of pre-code reinforced concrete shear wall buildings in Romania
Authors: Barnaure M
Published: August 2021

Prior to 1963, when the first earthquake design code was implemented in Romania, mid height (over 8 storeys) shear wall buildings were already being built in some of the major cities. These buildings have important structural weaknesses when assessed using the current regulations. An 11 storeys residential building in Bucharest built in 1962 is analysed. Results show that the building is extremely vulnerable on the longitudinal direction, where the lateral resisting system is composed by only two shear walls. If bending capacity is lacking mainly at the base of the building, shear strength deficiencies are present over the entire height of the building, due to a lack of shear reinforcement in the walls. An analysis of several possible strengthening solutions is made, and conclusions are drawn regarding the feasibility of these solutions.
The effects of parameter uncertainties on the numerical plastic analysis of non-prismatic reinforced concrete beams
Authors: Khaleel Ibrahim S , Movahedi Rad M , Habashneh M A
Published: August 2021

Structural models and parameters are usually considered deterministic in most studies. However, test results revealed that uncertainties exist in most of these cases due to natural variability or lack of awareness. Therefore, uncertainty in structures is taking huge attention as it has an important role in the structures analysis and the calibration of designing code factors where it enhances the prediction of the models’ behavior. Despite this significance, existing knowledge concerning uncertainties and their parameters seems to suffer from a lack of knowledge especially in unique structures like non-prismatic reinforced concrete beams which are considered a special case in structural engineering for having variable depth across beam section. The present paper aims to examine some uncertainties facing structural engineers and their role in the non-prismatic reinforced concrete beam behavior considering different variables and parameters. Concrete Damage Plasticity (CDP) constitutive model is used to calibrate the numerical model according to the data obtained experimentally. Then different uncertainty parameters were studied by applying several simulations to find out their effect on models’ behavior. The results seem to provide a better understanding of the uncertainties and their effect on the non-prismatic reinforced concrete beams. Lastly, finite element simulations are applied using ABAQUS.
FEM computational models of shear walls with openings
Authors: Handruleva A , Dimitrova A
Published: August 2021

This study is devoted to the comparison of shear wall computational models and the juxtaposition of displacement and stress fields. Two types of numerical models are compared. The first type concerns discretization of the geometry by using the beam finite elements model, and the second type-with plane finite elements. The displacements and the internal forces are used as the key indicators for the comparison of the mechanical behaviour. Some conclusions have been drawn, as well as recommendations have been made on the application of the juxtaposed type computational models and their practical application in real life.
Finite element analysis of square concrete columns strengthened with carbon fiber composites in different configurations
Authors: Almagsoosi A N A , Georgescu D P
Published: August 2021

This paper offers the findings of numerical study carried out to evaluate the behavior of low strength concrete columns in square section strengthen by Carbon Fiber Reinforced Polymer (CFRP) composites and subjected to axial compression load. In this study, a three dimensional non-linear finite element formulation model has been presented using ANSYS-16.1 (software computer program) to analyse low strength concrete columns in square section strengthen by CFRP composites in different configurations, to evaluate the improvement in the ultimate load capacities of columns as a result of CFRP confinement, and to study the impact of the most important parameters such as: compressive strength of concrete, thickness of the CFRP layers jacket/strips and the presence of steel reinforcement on the performance of th modelled columns subjected to compression load. A comparison has been made between the results obtained from the Finite Element Analysis (FEA) and experimental data. The results of the numerical FEA study showed that, external strengthening with CFRP composites are very effective in upgrading the ultimate load of square concrete columns. In addition, the findings revealed good agreement between the ANSYS and the experimental test results. The results obtained from the parametric study revealed that when the CFRP layers increased from 2 to 3 layers and from 2 to 4 layers the ultimate loads of the columns increased about (2%-10%) and (7%-15%) respectively. While the compressive strength showed significant effect on the upgrade of the ultimate load, when increase the compressive strength to 42MPa and to 60 MPa, the ultimate load increased to about 220% and to about 300% respectively. The presence of steel reinforcing did not show reasonable effect on the ultimate load.
Preparation of MSBF reinforced PP composites & research on their mechanical and sound insulation properties
Authors: Zhao Lei , Qian Fei , Liu Ling , Wei Li
Published: August 2021

Nowadays, most researchers at home and abroad are studying the planting of seashore mallow and the efficient extraction of mallow seed oil, while the remaining mallow stems are generally incinerated or discarded. In fact, there are a lot of bundle fibers in mallow stem bark(MSB), and their physical properties such as strength and modulus are close to those of jute and flax. So developing the fiber-reinforced composites of mallow stem bark fiber(MSBF) has high potential application value. Using mallow stem bark as raw material, MSBF was extracted by alkali degumming process, and MSBF reinforced polypropylene(PP) composites with fiber mass fraction of 40%, 30%, 20%, 10% and 0% were prepared by using alkali-treated MSBF as reinforcement and PP fiber as matrix. The effects of fiber mass fraction on tensile, bending and sound insulation properties of MSBF reinforced PP composites were discussed. The results show that when the fiber mass fraction was 30%, the tensile breaking strength, tensile modulus and bending modulus of the composite were the highest, and the bending strength gradually enchanes with the increase of the fiber mass fraction of MSBF. When the fiber mass fraction exceeds 10%, the voltage peak attenuation rate of MSBF reinforced PP composites increases first and then decreases with the increase of sounding frequency. When the sound frequency is the same, the lower the fiber mass fraction, the worse the sound insulation performance of the composite. When the fiber mass fraction exceeds 30%, the voltage peak attenuation rate decreases.
Methylmercury in lake bed soils during re-flooding of an Appalachian reservoir in the northeastern USA
Authors: Eklöf Karin , Drohan Patrick , Needoba Joseph , Landefeld Sally , Peterson Tawnya D , Hu Haiyan , Iavorivska Lidiia , Boyer Elizabeth W
Published: August 2021

Mercury methylation, where inorganic mercury (Hg) is converted to methylmercury (MeHg), can increase in soils when flooded. While effects of the initial flooding of soils on MeHg production have been well studied, less is known about impacts of re-flooding on MeHg production. Lake Perez, an impounded recreational reservoir in the Appalachian Highlands, was completely drained then re-filled 7 years later. We use a combination of chemical, soil physical, and microbial data to quantify changes in MeHg before and after re-flooding of the lakebed. Portions that were transiently saturated due to pluvial flooding had the highest pre-flooded MeHg concentrations. When the lake was re-flooded, concentrations of MeHg in subaqueous soils increased by a factor of 2.74 (+174%) on average. Substantial variability was observed among the sampling sites, with smaller increases in MeHg at sites subjected to seasonal flooding during periods when the reservoir was drained. The increase of soil MeHg after re-flooding was lower in this study compared to studies that evaluated soil MeHg after initial flooding, indicating that re-flooding of a former lake bed caused a smaller response in MeHg production compared to initial flooding of terrestrial land. This study advances understanding of the environmental impact of impounded reservoirs.
Radio-frequency characterization of a supercurrent transistor made of a carbon nanotube
Authors: Mergenthaler M , Schupp F J , Nersisyan A , Ares N , Baumgartner A , Schönenberger C , Briggs G A D , Leek P J , Laird E A
Published: August 2021

A supercurrent transistor is a superconductor–semiconductor hybrid device in which the Josephson supercurrent is switched on and off using a gate voltage. While such devices have been studied using DC transport, radio-frequency measurements allow for more sensitive and faster experiments. Here a supercurrent transistor made from a carbon nanotube is measured simultaneously via DC conductance and radio-frequency reflectometry. The radio-frequency measurement resolves all the main features of the conductance data across a wide range of bias and gate voltage, and many of these features are seen more clearly. These results are promising for measuring other kinds of hybrid superconducting devices, in particular for detecting the reactive component of the impedance, which a DC measurement can never detect.
High levels of Tryptophan reduce cell wall or membrane stress tolerance in Saccharomyces cerevisiae
Authors: Ohashi Kazuto , Chaleckis Romanas
Published: August 2021

Tryptophan (Trp) is a proteinogenic aromatic amino acid; however, high levels of Trp are toxic in animals and yeast with unknown mechanisms. Previously, we suggested that aromatic aminotransferase Aro9 is important for excess Trp degradation. Besides, Schroeder and Ikui showed that aro9Δ is sensitive to membrane stress by sodium dodecyl sulfate. Therefore, Trp accumulation may reduce the cell wall or membrane (CW/M) stress tolerance through participation of cell wall integrity (CWI) pathway, which detects and responds to CW/M perturbations. In this study, we found that yeast mutants of the CWI mitogen-activated protein kinase cascade were susceptible to excess Trp. Also, the Trp degradation deficient mutant aro8Δ aro9Δ cells, in which Trp accumulation was confirmed, were sensitive to several CW/M stresses. These results indicated that accumulation of Trp is adverse for the CW/M stress resistance and may disturb appropriate signal transduction responding to the stress.
Construction of recombinant Escherichia coli producing nitrogenase-related proteins from Azotobacter vinelandii
Authors: Tatemichi Yuki , Nakahara Takeharu , Ueda Mitsuyoshi , Kuroda Kouichi
Published: August 2021

Biological nitrogen fixation by nitrogenase has attracted attention as an alternative method to chemical nitrogen fixation, which requires large amounts of fossil fuels. Azotobacter vinelandii, which produces an oxygen-sensitive nitrogenase, can fix nitrogen even under aerobic conditions; therefore, the heterologous expression of nif-related genes from A. vinelandii is a promising strategy for developing a biological nitrogen fixation method. We assembled 17 nif-related genes, which are scattered throughout the genome of A. vinelandii, into synthetic gene clusters by overlap-extension-PCR and seamless cloning and expressed them in Escherichia coli. The transcription and translation of the 17 nif-related genes were evaluated by RT-qPCR and LC-MS/MS, respectively. The constructed E. coli showed nitrogenase activity under anaerobic and microaerobic conditions. This strain would be a useful model for examining the effect of other genes from A. vinelandii on nitrogen fixation by expressing them in addition to the minimal set of nif-related genes.
Characterization and proposed spontaneous deletion mechanism of AVR-Pik locus in Pyricularia oryzae
Authors: Thwin Phyo Han , Funabiki Mai , Tomita Yuki , Yamazaki Takehiko , Abe Ayumi , Sone Teruo
Published: August 2021

In phytopathogenic fungi, a mutation in the avirulence gene can lead to the breakdown of resistance in the host plant. The nucleotide sequences of the AVR-Pik locus in the strain Ina168 and its spontaneous mutant Ina168m95-5 of Pyricularia oryzae were determined. An AVR-Pik spontaneous deletion mechanism of Ina168m95-5, including multiple homologous recombination events involving repetitive transposable elements, is proposed.