bluuebunny/crossref_metadata_2025 huggingface dataset:
Is there a Threshold Preoperative WOMAC Score That Predicts Patient Satisfaction after Total Knee Arthroplasty?
Authors: Clement Nicholas D. , Weir David J. , Holland James , Deehan David J.
Published: December 2019

The aim of this study was to identify threshold preoperative Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores that were predictive of patient dissatisfaction 1 year after total knee arthroplasty (TKA). A retrospective cohort of 3,324 patients undergoing a primary TKA was identified from an established arthroplasty database. Patient demographics, comorbidities, and the WOMAC score were collected preoperatively. Patient satisfaction was assessed at 1 year using four questions that focused on: overall outcome, activity, work, and pain. Receiver operating characteristic (ROC) curve analysis was used to identify threshold values predictive of dissatisfaction. The overall satisfaction rate at 1 year was 89.7% (n = 2982). Patients who were satisfied had a significantly greater preoperative pain (3.6, 95% confidence interval [CI] 1.6–5.6, p < 0.001) and functional (4.5, 95% CI 2.6–6.5, p < 0.001) component and total (4.2, 95% CI 2.3–6.0, p < 0.001) WOMAC scores compared with those who were dissatisfied. ROC curve analysis demonstrated the preoperative pain (p = 0.001) and functional (p < 0.001) components and total (p < 0.001) WOMAC scores were significant predictors of satisfaction. Patients scoring < 36 for the pain and function components and < 35 for the total WOMAC score were more likely to be dissatisfied with their overall outcome, but the area under the curves (AUCs) for these predictive threshold values were 0.56, 0.54, and 0.60, respectively, indicating poor prognostic value. A similar finding was observed for satisfaction with pain relief and ability to work and recreational activities; however, in addition the stiffness component was also a significant (p < 0.001) predictor with a threshold value of < 43. Again, these thresholds were of poor prognostic value with an AUC of less than 0.57 for all these satisfaction questions. Threshold values in the preoperative component and total WOMAC scores were not reliable prognostic indicators of overall patient satisfaction or for satisfaction with pain relief, ability to do work, or recreational activities after TKA.
Accounting for firm heterogeneity in global value chains
Authors: Fortanier Fabienne , Miao Guannan , Kolk Ans , Pisani Niccolò
Published: December 2019

The growing interest in global value chains (GVCs) has been paired with a greater appreciation of the need for better measurement methods, as reflected by recent initiatives from academia and leading international organizations. This research note focuses on one method to measure GVCs that has been recommended in recent scholarly work, namely input–output models, but goes beyond the industry level of analysis by introducing intra-industry firm heterogeneity. Our illustrative application to multinational enterprises (MNEs) versus domestic firms’ participation in GVCs enhances our understanding of their specific role in GVCs and how such engagement varies across countries and industries. While showing that MNEs’ contribution to value-added exports is considerably smaller than what is suggested by traditional trade statistics, our findings also, interestingly, document that the higher import content of exports of MNEs can go hand in hand with the creation of local backward linkages as a function of their much higher specialization in only parts of the production process vis-à-vis domestic firms. By answering relevant questions on MNEs’ engagement in GVCs that have hitherto been impossible to address comprehensibly and in a cross-country comparative setting, this application illustrates how the methodology has great potential for international business research.
Enhanced optoelectronic properties of thermally evaporated Sb-doped ZnO nanowires via defect structures
Authors: Wang Chih-Chiang , Lin Wei-Chen , Shieu Fuh-Sheng , Shih Han C.
Published: December 2019

Sb-doped ZnO nanowires were fabricated on Si (100) substrates by thermal evaporation via the vapor-liquid-solid mechanism at 850 °C, and their optoelectronic properties were examined. Two prominent emission regions at the near band-edge emission and deep-level emission of the pure ZnO nanowires were observed in the photoluminescence spectra. Doping with Sb reduced the intensities of near band edge emission and deep-level emission. Almost no near band-edge emission signal was obtained at Sb ≥ 2.2 at. % and almost no deep-level emission signal was obtained at Sb ≥ 5.46 at. %, owing to the formation of metallic Sb and the +5 oxidation state of the Sb2O5 phases. These results suggest that the Sb dopant content is the critical factor in improving the optoelectronic properties of Sb-doped ZnO nanowires, as revealed by their photoluminescence spectra.
Why thermal effects can decrease the efficiency of high-quality LEDs
Authors: Bandari Anashe
Published: December 2019

New research sought to understand the mechanism of thermal droop, a process that decreases LED efficiency at increased temperatures.
Unit cell angle rotation creates multifunctional acoustic metamaterial
Authors: Frank Jodi Ackerman
Published: December 2019

Researchers design tunable acoustic metamaterial based on rotating C-shaped unit cells to create three types of acoustic lenses—converging, diverging and deflection.
Barriers and enablers to implementation of antenatal smoking cessation guidelines in general practice
Authors: Reeks Rohan , Padmakumar Govind , Andrew Bridgette , Huynh Danica , Longman Jo
Published: December 2019

Smoking is a major preventable cause of adverse outcomes in pregnancy. Despite the existence of smoking cessation support guidelines, many pregnant smokers do not receive support in quitting. The aim of this study was to identify and understand the facilitators and barriers experienced by GPs in implementing the 5As of smoking cessation support with pregnant women. The results of this study may help in shaping interventions to support GPs in implementing the guidelines. This was a qualitative study using semi-structured interviews built around the Theoretical Domains Framework. Participants were 15 GPs, and thematic analysis was used to identify relevant themes. Perceived barriers to implementing guidelines included unfamiliarity with the 5As, uncertainty using nicotine replacement therapy, lack of time, and fears of damaging rapport. Perceived facilitators included high levels of knowledge and skills, patients’ expectations and a recognition that smoking cessation was a fundamental and essential part of the GPs’ role in antenatal care. Educating and training GPs regarding the 5As and NRT (nicotine replacement therapy) use in pregnancy may have a role in improving delivery of smoking cessation support. The strong overall commitment to provision of smoking cessation support among GPs may also have a role in developing interventions in the future.
Constructing authorial pseudonyms and authorial identity in online fanfiction communities
Authors: Donlan Lisa
Published: December 2019

This article undertakes the first linguistic analysis of the innovative online pseudonyms (e.g.,
, <00Q007Narry>, ) used by fanfiction authors. Specifically, this
research explores the most frequent lexical formation processes employed when creating pseudonyms, why these processes are used,
and what they reveal about authorial identity in fanfiction communities. The most common formation methods identified across the
600 names analysed are compounding, blending, and variant spellings. All three of these processes allow authors to create
memorable and unique names which distinguish their work from that of other writers in their community. Indeed, despite their use
of pseudonyms, these authors are still highlighting their individual authorial identities, and they do this by turning the process
of creating a pseudonym into a ludic experiment in linguistic innovation. Consequently, future studies should further explore the
relationship between self-selected names and the articulation of identity.
Biological control in Chile.
Authors: Barra-Bucarei L. , Moreno L. D. , Iglesias A. F.
Published: December 2019

The first introduction of a predator of olive black scale in 1903 marked the start of biocontrol in Chile. In 1915 the Ministry of Agriculture began a programme of introduction of beneficial organisms and since then approximately 200 species of beneficial insects have been introduced into the country. Many complete and permanent successes were obtained in the period 1900-1969 and examples are control of: olive black scale; scales in grapevine, citrus, berries, avocado and other fruit; mealybugs in citrus, grapevine, avocado and other fruit; and woolly apple aphid in apple. The use of microbial control agents started in the 1950s and numerous microorganisms have since been collected, identified and mass produced to control pests and diseases. Weed biocontrol began in Chile in the 1950s with successful classical biocontrol of St John's wort with a phytophagous weevil, followed in the 1970s by using a plant pathogenic fungus for control of Rubus ulmifolius (zarzamora) and in the 1980s-1990s by releasing phytophagous weevils, moths and mites for control of gorse weed. An important large project executed during the 1970s and 1980s resulted in classical biocontrol of several virus-transmitting aphid species on thousands of hectares of wheat and barley. In forestry, parasitoids have been introduced for classical biocontrol of European pine shoot moth and of the sirex wood wasp in pine, and the eucalyptus psyllid in eucalyptus on vast areas. Currently, there are many commercial and governmental research initiatives for predators, parasitoids, entomopathogenic fungi and nematodes, and with bacteria and fungi for pest and disease control.
Biological control in Costa Rica.
Authors: Blanco-Metzler H. , Morera-Montoya R.
Published: December 2019

The first biological control activities in Costa Rica date from around 1915, but it was only in the 1950s that studies were conducted on the introduction, mass rearing and release of biocontrol agents in crops such as fruit trees, coffee, bananas, sugarcane, rice and pineapple. Subsequently, the use of entomopathogens became important in the 1990s as a strategy to be used in integrated pest management (IPM) programmes. From the 1990s, biocontrol laboratories were established and alliances were developed with national and international institutions and universities to strengthen biocontrol activities in the country. Currently, new areas of study have been incorporated in biocontrol research, such as molecular biology, host-plant resistance, identification of new biocontrol agents, the use of X-rays to sterilize hosts of natural enemies and the use of volatile compounds produced by the plant after pest attack to attract natural enemies. All these activities help to develop sustainable pest management. Implementation of biocontrol in Costa Rica will keep increasing, since there is great pressure to reduce the use of chemical pesticides for all the export crops.
Biological control in Dominica.
Authors: Lenteren J. C. van
Published: December 2019

Introduction of two tachinid parasitoid species in 1951 for biocontrol of the sugarcane borer resulted in good control. Native and imported parasitoids were evaluated in the 1960s for control of fruit flies and noctuid moths on various fruits in Dominica, but none of them was effective. Several other imports of exotic natural enemies in this period for classical biocontrol of banana weevil, coffee leaf miner and diamondback moth were not successful. Complete island-wide control of the citrus blackfly was obtained after releases of two exotic parasitoids at the end of the 1990s.
Biological control in continental Ecuador and the Galapagos Islands.
Authors: Castillo C. C. , Gallegos P. G. , Causton C. E.
Published: December 2019

Biological control has been used against agricultural pests and diseases on mainland Ecuador for over 80 years and its use as a pest management tool is increasing. Classical and augmentative biocontrol techniques are now commonly used for a wide range of crops, fruits and flowers that are grown using traditional or organic farming approaches. The Ecuadorian government, through the Ministry of Agriculture and the National Institute of Agricultural Research, strongly encourages the use of biocontrol, conducts research on potential biocontrol agents, and has helped to establish laboratories for the production of biocontrol agents in different provinces. There are also now at least four Ecuadorian companies that produce entomopathogens, insect predators and parasitoids as well as cooperation agreements set up with international suppliers. It is estimated that augmentative biocontrol was used on over 65,000 ha of farmland in 2017, and conservation biocontrol on 150,000 ha. The area under classical biocontrol was difficult to reliably estimate. The aim of Ecuador is to offer more high-quality commodities that are produced using methods with low negative ecological impact. On the Galapagos Islands, classical biocontrol has been used once to control the invasive cottony cushion scale, which was seriously affecting threatened endemic plant species. Following the success of this programme, it is now being considered as a management tool for invasive plant and insect species, as well for the most damaging agricultural pests.
Biological control in Guatemala.
Authors: Lenteren J. C. van
Published: December 2019

Biological control was initiated in Guatemala in the 1990s, after costs for chemicals had increased substantially and had resulted in a drastic decrease in production of, for example, cotton and tomato. Most often, augmentative biocontrol is used in Guatemala. Examples of successful programmes are control of: (i) lepidopterans in cotton and vegetables by microbial agents and egg parasitoids; (ii) cotton leafworm by egg parasitoids and a predator in cotton; (iii) coffee berry borer with a parasitoid and a microbial agent; (iv) sugarcane borer with a parasitoid and a microbial agent; (v) diamondback moth with parasitoids in cruciferous crops; and (vi) white grub in maize with an entomopathogenic nematode. In 1998, populations of Anopheles mosquitoes, which are vectors of malaria, were successfully reduced by killing their larvae with microbial agents, resulting in a 50% lower malaria prevalence. A recently started project concerns classical biocontrol of the Asian citrus psyllid with a parasitoid. Biocontrol is expected to grow because of, inter alia, demands for residue-free food by countries to which Guatemala exports.
Biological control in Guyana.
Authors: Lenteren J. C. van
Published: December 2019

Conservation biological control, implemented in the 1910s by erecting perches in rice fields for insectivorous birds, resulted in effective control of the fall armyworm. Guyana is supposed to be the first country where the tachinid parasitoid Lydella minense, which had been collected in 1932 in Brazil, was successfully introduced for sugarcane borer control in the same year. During this period, several native natural enemies of this borer, as well as of other pests, were also identified as a result of prospecting projects. Guyana provided some of these species to other countries in the region. Classical biocontrol projects during the period 1970-2000 were attempted and the pink hibiscus mealybug was brought under complete control in 1998 by a parasitoid and a predator. Current projects concern classical biocontrol of the carambola fruit fly by parasitoids, augmentative control of the red palm mite by predatory mites, augmentative control of the palm castniid by a native entomopathogenic bacterium and conservation biocontrol of pests in rice.
Biological control in Honduras.
Authors: Trabanino R. , Pitty A. , Cave R. D.
Published: December 2019

Prospecting for natural enemies and microbial control agents has been an important activity in Honduras since 1968, with as major projects the inventories of parasitoids of diamondback moth, striped grass looper, fall armyworm, Mexican cabbage butterfly, dipteran leaf miners, diaspids, coccids and aleurodids. The creation of the Center for Biological Control in Central America within the Zamorano University in 1989 was the starting point of teaching, research and the implementation of classical, augmentative and conservation biocontrol in the region. The Center trains hundreds of students from 21 countries each year and thesis work by its students results in a lot of knowledge about natural enemies, microbial agents and their mass-production methods. In 1990, introduction of phytophagous weevils for classical control of water hyacinth was a success. Microbial control of diamondback moth with a virus was tested in the 1990s, followed by the development and production of several fungus-, virus- and nematode-based formulations for control of pests and diseases. Trichoderma, Metarhizium, Isaria, Lecanicillium and Beauveria are now registered as commercial products and are also used in other countries in the region. In 2008 a successful project was started to reduce agrochemical use in vegetables, consisting of local mass rearing of several predators for augmentative control of thrips, aphids, mites and whitefly, and training of hundreds of farmers. A similar successful project concerned training courses on biocontrol of the sweet potato weevil for more than 5,000 farmers in the poorest area of the country.
Biological control in Jamaica.
Authors: Sherwood M. A. , Lenteren J. C. van
Published: December 2019

Jamaica has a rich history of successful biological control of more than 25 pests of economic and quarantine importance. Approximately 14 classical, 13 natural and six augmentative biocontrol programmes were recorded, as well as two fortuitous introductions. The programmes concerned control of key pests on: (i) citrus, such as citrus blackfly, citrus red scale, cottony cushion scale, citrus root weevils, brown citrus aphid, lime swallowtail butterfly and Asian citrus psyllid; (ii) sugarcane, mainly sugarcane borers; (iii) banana, the banana weevil; (iv) cocoa, the cocoa thrips; (v) coconut, with coconut scale, two aphid species and red palm mite; (vi) sweet potato, sweet potato weevil; (vii) crucifers, with diamondback moth and cabbage looper; (viii) coffee, with coffee berry borer and coffee leaf miner; (ix) residential fruit tree crops and ornamentals, with pink hibiscus mealybug and ensign scale; (x) papaya, with papaya mealybug and citrus root weevil; and (xi) onion and scallion, with beet armyworm. Biocontrol agents used were species of parasitoids, predatory beetles and mites, nucleopolyhedroviruses, and entomopathogenic fungi and nematodes. Jamaica served as a provider of biocontrol agents for the Caribbean and Hawaii. A biocontrol facility is currently being built to develop control methods for endemic and invasive pests.
Biological control in Paraguay.
Authors: Cabral Antúnez C. C. , Resquín Romero G. , Gómez López V. A.
Published: December 2019

Biological control in Paraguay started in the 1980s with the use of a baculovirus for augmentative biocontrol of the soybean caterpillar and application of parasitoids to control the sugarcane borer. Since 2000, organic production has stimulated use of biocontrol. Also in 2000, large-scale prospecting for natural enemies and microbial control agents in crops such as cotton, maize, bean, peanut, sesame, soybean and sugarcane was initiated. Many natural enemies found during these prospecting activities are currently used in conservation biocontrol programmes. Several entomopathogenic and phytopathogenic agents have been registered and are used in Paraguay.
Cassava: origin and history.
Authors: Lebot V.
Published: December 2019

This chapter provides information on the origin and domestication of Manihot sp. and the discovery of the crop by western explorers. The present geographical distribution of cassava, mostly in tropical countries, is also discussed.
Cassava: agronomy.
Authors: Lebot V.
Published: December 2019

This chapter focuses on the various factors affecting the success of cassava cultivation, such as seed systems and propagule selection, soil preparation, plant densities and crop establishment, intercropping, weeding, fertilizer application and nutrient disorders and harvesting.
Cassava: pests and diseases.
Authors: Lebot V.
Published: December 2019

Cassava is attacked by numerous pests and diseases that cause significant losses, especially in South America, its area of origin. Some pathogens attack only the stakes and invade the vascular system, constituting primary sources of infection, while others attack only foliar or root tissues. This chapter provides information on the various nematode, arthropod and insect pests and bacterial, fungal and viral pathogens affecting cassava and the importance of integrated methods in the management of thsese pests and diseases.
Cassava: postharvest quality and marketing.
Authors: Lebot V.
Published: December 2019

This chapter focuses on the chemical composition and physiological disorders of freshly stored cassava roots and the efficacy of various storage methods and traditional and industrial processing techniques in ensuuring the quality of cassava roots. The establishment of some marketing and quality standards to regulate and monitor cassava root quality is also discussed.
Sweet potato: developmental physiology.
Authors: Lebot V.
Published: December 2019

This chapter focuses on the effects of various factors, such as photoperiod, temperature, nutrition, water deficit and stress and climate change, on the growth and development of sweet potatoes. The adaptability of various sweet potato germplasm to these factors is also discussed.
Sweet potato: postharvest quality and marketing.
Authors: Lebot V.
Published: December 2019

This chapter focuses on the postharvest quality and marketing of sweet potatoes. Chemical composition, physiological disorders, quality standards, storage methods, traditional processing techniques, and industrial processing are discussed.
Yams: taxonomy and botany.
Authors: Lebot V.
Published: December 2019

This chapter focuses on the classification, plant morphology, and cytology of major cultivated and related Dioscorea species.
Aroids: breeding and genetics.
Authors: Lebot V.
Published: December 2019

Modern aroid (Alocasia, Amorphophallus, Colocasia, Cyrtosperma and Xanthosoma) production is becoming intensive and oriented to the market, which requires cheap, healthy and high-quality products. The aim of taro breeding is to create genotypes that are high yielding, with corms of good eating quality, resistant to diseases, tolerant to pests and well adapted to specific environments (paddy or dryland conditions). This chapter discusses the breeding objectives and criteria, sexual reproduction and sterility, crossing techniques and true seed production, selection methods and programmes, heritability of major traits, and genotype × environment interactions of aroids. The use of related species, polyploidy breeding, use of molecular markers, transgenic technologies, and germplasm conservation are also described.
Aroids: agronomy.
Authors: Lebot V.
Published: December 2019

Aroids can be grown throughout the year in the wet tropics. They are best adapted to high temperatures, a moist environment and high humidity. Evenly distributed rainfall, between 200 and 300 mm/month, is ideal for optimum growth and production. Irrigation is, however, necessary for taro and swamp taro (Cyrtosperma merkusii) in low rainfall areas, while cocoyam (Xanthosoma sagittifolium), giant taro (Alocasia macrorrhizos) and elephant foot yam (Amorphophallus paeoniifolius) are more drought tolerant. For all species, and for a given genotype, the time needed to reach maturity varies according to temperature, sunlight and water availability. This chapter discusses the agronomy of aroids, including the seed systems and propagule selection, soil preparation, plant densities and crop establishment, intercropping, weeding, fertilizer application, nutrient disorders, and harvesting.
Aroids: postharvest quality and marketing.
Authors: Lebot V.
Published: December 2019

Cocoyam, taro and other aroids (Alocasia, Amorphophallus and Cyrtosperma) have much potential in terms of fresh and processed products and are, in fact, industries with considerable expansion potential, especially as biofunctional foods. Taro is already processed and prepared into many consumable and diverse forms. Corms may be roasted, baked, boiled, steamed or fried. They may be processed into fresh or fermented paste, canned corm portions, flour, beverage, chips and flakes. The leaves, petioles, stolons and inflorescences are also consumed and are steamed or boiled. This chapter describes the chemical composition, physiological disorders in freshly stored corms, marketing, quality standards, storage methods, traditional processing techniques, and industrial processing of aroids.
Study on microstructure and properties of mechanically electrodeposited nanocrystalline Fe-Ni alloy
Authors: Zhu Zengwei , Guo Yongliang , Jiang Zhongjiang , Tang Xiaocong
Published: December 2019

Fe-Ni alloys were prepared by electrodeposition process assisted with mechanical polishing and analyzed by comparison with the traditional electrodeposition process. The results showed that mechanical polishing can significantly affect the crystalline growth and grain refinement resulted.
Simultaneously the polishing can significantly enhance the micro-hardness and reduce the thermal expansion coefficient (TEC) of the electrodeposited Fe-Ni alloy. Both micro-hardness and thermal expansion coefficient decrease with increase of current density due to the grain coarsen. A promising
technology for achieving Fe-Ni alloy with low TEC and high strength can be expected.
Electrical and Magnetic Properties of Pb0.8La0.2Fe0.1Cr0.1Ti0.8O3
Authors: Nayak Amrita , Patri S. K. , Deepti P. L. , Behera B.
Published: December 2019

The dielectric spectroscopy of a new ceramic material; Pb0.8La0.2Fe0.1Cr0.1Ti0.8O3 has been studied. The compound was prepared by solid-state reaction method. The structural study from X-ray diffraction technique shows
the formation of polycrystalline sample with orthorhombic crystal system at room temperature. Dielectric property of this material has been characterized in the temperature range of 25–450°C and frequency range of 100 Hz – 1 MHz respectively. The phase transition
temperatures were at two different temperatures for each frequency. The nature of ac conductivity shows the negative temperature coefficient of resistance type behavior of the material.
Bilinear Forms and Dark-Dark Solitons for the Coupled Cubic-Quintic Nonlinear Schrödinger Equations with Variable Coefficients in a Twin-Core Optical Fiber or Non-Kerr Medium*
Authors: Chu Mei-Xia , Tian Bo , Yuan Yu-Qiang , Zhang Ze , Tian He-Yuan
Published: December 2019

Twin-core optical fibers are applied in such fields as the optical sensing and optical communication, and propagation of the pulses, Gauss beams and laser beams in the non-Kerr media is reported. Studied in this paper are the coupled cubic-quintic nonlinear Schrödinger equations with variable coefficients, which describe the effects of quintic nonlinearity for the ultrashort optical pulse propagation in a twin-core optical fiber or non-Kerr medium. Based on the integrable conditions, bilinear forms are derived, and dark-dark soliton solutions can be constructed in terms of the Gramian via the Kadomtsev-Petviashvili hierarchy reduction. Propagation and interaction of the dark-dark solitons are presented and discussed through the graphic analysis. With different values of the delayed nonlinear response effect b(z), where z represents direction of the propagation, the linear- and parabolic-shaped one dark-dark soltions can be derived. Interactions between the parabolic- and periodic-shaped two dark-dark solitons are presented with b(z) as the linear and periodic functions, respectively. Directions of velocities of the two dark-dark solitons vary with z and the amplitudes of the solitons remain unchanged can be observed. Interactions between the two dark-dark solitons of different types are displayed, and we observe that the velocity of one soliton is zero and direction of the velocity of the other soliton vary with z. We find that those interactions are elastic.
An Optimal Analysis for 3D Flow of Prandtl Nanofluid with Convectively Heated Surface
Authors: Ullah Malik Zaka , Alghamdi Metib
Published: December 2019

In this paper, the magnetohydrodynamic 3D flow of Prandtl nanoliquid subject to convectively heated extendable surface has been discussed. A linear stretching surface makes the flow. Thermophoretic and Brownian motion impacts are explored. Heat transfer for convective procedure is considered. Prandtl liquid is taken electrically conducted through applied magnetic field. Suitable non-dimensional variables lead to strong nonlinear ordinary differential system. The obtained nonlinear differential systems are solved through optimal homotopic technique. Physical quantities like skin friction coefficients and Nusselt number are explored via plots. It is observed that effects of Hartman parameter and Biot number on temperature and concentration are quite similar. Both temperature and concentration are enhanced for larger values of Hartman parameter and Biot number.
Quantum magnetometry using two-stroke thermal machines
Authors: Bhattacharjee Sourav , Bhattacharya Utso , Niedenzu Wolfgang , Mukherjee Victor , Dutta Amit
Published: December 2019

The precise estimation of small parameters is a challenging problem in quantum metrology. Here, we introduce a protocol for accurately measuring weak magnetic fields using a two-level magnetometer, which is coupled to two (hot and cold) thermal baths and operated as a two-stroke quantum thermal machine. Its working substance consists of a two-level system (TLS), generated by an unknown weak magnetic field acting on a qubit, and a second TLS arising due to the application of a known strong and tunable field on another qubit. Depending on this field, the machine may either act as an engine or a refrigerator. Under feasible conditions, determining this transition point allows to reduce the relative error of the measurement of the weak unknown magnetic field by the ratio of the temperatures of the colder bath to the hotter bath.
Nonreciprocal wave propagation and parametric amplification of bulk elastic waves in nonlinear anisotropic materials
Authors: Zakeri Mahsa , Keller Scott M , Wang Yuanxun Ethan , Lynch Christopher S
Published: December 2019

Parametric amplification of an elastic wave and a framework for using elastic waves that could enable a new generation of high performance, low noise acoustic amplifiers, mixers and circulators are presented. Using a novel approach with nonlinear materials produces highly desirable non-reciprocal characteristics. Parametric amplification of a weak elastic signal wave is achieved by an elastic pump wave of higher intensity. By careful selection of material orientation together with precise excitation of signal and pump waves, ‘up frequency conversion’ is suppressed and selective amplification of the elastic signal wave occurs at its original frequency. In addition, a general mathematical framework is developed and used for analytical studies of coupled wave equations in nonlinear anisotropic materials. The results obtained from the analytical studies are verified using a finite element implementation.
An algorithm for Bragg coherent x-ray diffractive imaging of highly strained nanocrystals
Authors: Wang Ziyi , Gorobtsov Oleg , Singer Andrej
Published: December 2019

By using phase retrieval, Bragg coherent diffractive imaging (BCDI) allows tracking of three-dimensional displacement fields inside individual nanocrystals. Nevertheless, during structural phase transformations, significant strains (1% and higher) are common, and BCDI fails due to the Bragg peak distortions. Here we present and advanced BCDI algorithm enabling imaging three-dimensional strain fields in highly strained crystals with separated structural phases. We test the algorithm on particles simulated to undergo a structural phase transformation. While the conventional algorithms fail in unambiguously reconstructing the phase morphology, our algorithm correctly retrieves the morphology of coexistent phases with a strain difference of 1%. The key novelty is the simultaneous reconstruction of multiple scans of the same nanoparticle at snapshots through the phase transformations. The algorithm enables visualizing phase transformations in nanoparticles of lithium-ion, sodium-ion nanoparticles, and other nanoparticulate materials in working conditions (operando).
Resolving non-homogeneous linear differential equations using the undetermined method coefficients and variation of parameters by means of GeoGebra
Authors: Funes Jorge Olivares , Kari Elvis Valero
Published: December 2019

In this paper, it is shown how non-homogeneous linear differential equations, especially those of the second order, are solved by means of GeoGebra applets, This is done by indeterminate coefficient methods and variation of parameters, in the course of differential equations for engineering students of the University of Antofagasta in Chile. The use of free software GeoGebra has been increasing in the teaching of mathematics, mainly in non-homogeneous linear differential equations, because it facilitates the teaching and learning process
Modeling the process of attracting foreign investment in the Russian economy
Authors: MGaleeva G
Published: December 2019

In the paper, on the basis of an assessment of the development of the Russian economy, the sectors most in need of an investment are identified, taking into account the depreciation rate of basic production assets. Depreciation of fixed assets reflects the demand for investment in order to modernize and reconstruct production. Based on the data of the Federal State Statistics Service of Russia, a rating of economic sectors in terms of the degree of depreciation of fixed assets at the end of the year by type of economic activity for 2013-2018 is built. In addition, the paper presents a model for predicting the inflow of foreign direct investment in Russia, developed using the classical approach to estimating linear regression criteria, which is based on the least squares method (OLS). In compiling this regression model, the applied software package for econometric modeling GRETL (GNU Regression, Econometrics and Time-series Library) was used to predict the inflow of foreign investment. Forecasting the inflow of foreign investment in the Russian Federation is aimed at solving the following tasks: to determine the most competent direction of investment policy and activity using forecast estimates, as well as to assess the country’s investment attractiveness. However, a significant role in predicting this indicator is played by the determination of factors that have an impact on the future volume of foreign investment. In addition, the analysis of foreign investments, depending on the influence of various factors, can tell about those or other motives that guide foreign investors when investing their own capital.
On the two-component generalization of the (2+1)-dimensional Davey-Stewartson I equation
Authors: Serikbayev Nurzhan , Nugmanova Gulgassyl , Myrzakulov Ratbay
Published: December 2019

The geometric-gauge equivalent of the famous Ishimori spin equation is the (2+1)-dimensional Davey-Stewartson equation, which in turn is one of the (2+1)-dimensional generalizations of the nonlinear Schrodinger equation. Multicomponent generalization of nonlinear integrable equations attract considerable interest from both physical and mathematical points of view. In this paper, the two-component integrable generalization of the (2+1)-dimensional Davey-Stewartson I equation is obtained based on its one-component representation, and the corresponding Lax representation is also obtained.
Cosmological Yang-Mills model with k-essence
Authors: Razina O V , Tsyba P Yu , Myrzakulov R , Meirbekov B , Shanina Z
Published: December 2019

We considered the f(R) model of gravity with the Yang-Mills field and k-essence in four dimensions, together with the homogeneous, isotropic and flat Friedmann-Robertson-Walker universe. For this model we found equations of motion, a solution for a scale factor, a scalar field, a scalar potential is reconstructed, we studied the slow roll parameters. For the model under consideration, the of slow roll parameters satisfy the region of the inflationary stage. For later times was found the equation of state parameter ω, the deceleration parameter q the value of which corresponds to the accelerated expansion of the universe. Our model allows you to get an accelerated expansion of the universe in the inflationary period. Over time, the field decreases, rolls off slowly, viscosity has a lesser effect, and the universe leaves the inflationary regime, which shows the exponential dynamics of changes in the law of expansion of the universe.
Geometric characteristics for Camassa–Holm equation
Authors: Mussatayeva Assem , Myrzakulov Nurgissa , Altaibayeva Aziza
Published: December 2019

One of the actual problems of mathematical physics is to relate differential geometry and nonlinear differential equation. Research in this direction is very important, as the results are a theoretical and practical application. In this paper, we investigate the Camassa-Holm equation. It is well known that the integrable nonlinear Camassa-Holm equation play an important role in the study of wave propagation. We present the relationship between Camassa-Holm equation and soliton surfaces. The rst and second fundamental forms, surface area and curvature for Camassa-Holm equation are found.
Exponential variational integrators for the dynamics of multibody systems with holonomic constraints
Authors: Kosmas Odysseas
Published: December 2019

We here explore a geometric integrator scheme that is determined by a discretization of a variational principle using a higher-order Lagrangian that uses exponential type of interpolation functions. The resulting exponential variational integrators are here extended to conservative mechanical systems with constraints. To do so we first present continuous Euler-Lagrangian equations with holonomic constraints and then mimic the process for the discrete case. The resulting schemes are then tested to a typical dynamical multibody system with constraints, i.e the double pendulum showing the good long-time behavior when compared to other traditional methods.
A look to differential
Authors: Gómez A
Published: December 2019

This paper reveals results of a research related to the presentation of the concept of differential for functions of a variable, from some calculus textbooks. Given that the concept of differential is closely linked to the concepts of derivative, integral and differential equation, the objective is to analyze the different ways of presenting the concept from those instances, in order to determine whether the presentation facilitates its understanding. The research follows a qualitative methodology based on a bibliographic review and conceptual didactic analysis, proceeding from content analysis corresponding to the notion of differential. It was found that the concept of differential in textbooks is presented in a geometric context, as an increment of a variable and as a function, dispossessed of its arithmetic meaning, being impossible to suppress the concept in the formal construction of the calculus.
Metaphors in textbooks of differential equations
Authors: Gómez A
Published: December 2019

This research is an approach to the study of metaphors in the teaching of differential equations, present in textbooks. The objective is to analyse the cognitive metaphors that facilitate learning in the search for the solution of homogeneous linear differential equations. The methodology used was content analysis applied to a subjective sample of four university texts. The analysis allowed to find that the texts that use linear algebra make it easier the teaching of differential equations, and it is concluded that the metaphors from linear algebra are fundamentals in the teaching of linear differential equations, the basic concept facilitates the learning for the construction of the general solution of linear differential equations.
Large cells cancer volumetry in chest computed tomography pulmonary images
Authors: Huérfano Y , Vera M , Gelvez-Almeida E , Vera M I , Valbuena O , Salazar-Torres J
Published: December 2019

Lung cancer is the leading oncological cause of death in the world. As for carcinomas, they represent between 90% and 95% of lung cancers; among them, non-small cell lung cancer is the most common type and the large cell carcinoma, the pathology on which this research focuses, is usually detected with the computed tomography images of the thorax. These images have three big problems: noise, artifacts and low contrast. The volume of the large cell carcinoma is obtained from the segmentations of the cancerous tumor generated, in a semi-automatic way, by a computational strategy based on a combination of algorithms that, in order to address the aforementioned problems, considers median and gradient magnitude filters and an unsupervised grouping technique for generating the large cell carcinoma morphology. The results of high correlation between the semi-automatic segmentations and the manual ones, drawn up by a pulmonologist, allow us to infer the excellent performance of the proposed technique. This technique can be useful in the detection and monitoring of large cell carcinoma and if it is considering this kind of computational strategy, medical specialists can establish the clinic or surgical actions oriented to address this pulmonary pathology.
How to divide the water level and danger zone of mountain floods along the river in the hilly area
Authors: Yan Chengshan , Wang Weilin , Zheng Congqi
Published: December 2019

With the precision of mountain flood disaster prevention work in the hilly area, the local key areas (villages and towns) in the hilly areas have become the focus of disaster prevention. This paper introduces analytical process of the flood control capacity of village along river, gives the calculating method of water level-river discharge relationship in control section, puts forward a feasible method of calculating the disaster water level and counting number of people in danger zone by point projection and judging point-line relationship. And this method is calculated by taking typical village along river for instance. The results show that this method can ascertain the household that is the weakest in the aspect of flood control capacity by combining field investigation and determine the relationship between households and different frequencies of flood water line, thus the flood control capacity of village along the river can be calculated accurately.
Meso-damaged VIB analysis for whole failure process of rock
Authors: Jiang Junling , Ke Changren
Published: December 2019

Based on the VIB model and the similarity of VIB two parameters cohesive force law at micro scale and the rock’s stress-strain curve at macro scale, a density evoluting function
D(θ)
about the elements softened and damaged at micro scale is proposed. The fracture informations of rock material are incorporated into the constitutive equations which in incorporating the density revolving function
D(θ)
, two kinds state of the elements—air element and solid element are proposed to describe the process of micro element. According to the consistence hypothesis between AE accumulations and the damaged elements, the AE simulation of rock fracture process is realized. The reasonableness of meso-damaged VIB analysis for whole failure process of rock is proved by a rock’s uniaxial compression test.
Evolution characteristics and variability analyzation of rainfall and runoff based on time scale
Authors: Wang Caiyuan , Yang Zhongshan , Zang Min , Wang Yajuan
Published: December 2019

With the rapid development of economy, the hardening area of city is increasing, which leads to the change of the runoff production law in the city. In order to understand the change of urban rainfall and runoff in the changing environment, the control basin of the Dahongmen hydrological station of Liangshui river in Beijing was selected as the research object. Mann - Kendall nonparametric rank correlation test, Non-parametric Pettitt test and qualitative and quantitative models of the Variable fuzzy set were used to study the evolution characteristics and variability of rainfall and runoff based on the measured data from 1980 to 2015. The results show that the flood peak and flood amount in the 1990s were smaller than those in 1980s, and the flood peak and flood amount were significantly greater than those in the 1980s and 1990s after 2000. The actual maximum flood peak and flood amount had significantly rising trend. For variability analysis, the mutation point of annual rainfall and runoff occurred in 1996 and 1993 respectively. They did not change qualitatively on the time scale, but only showed the quantitative variation. This study results can provide a basis for rational decision of flood prevention departments.
Analysis of Deformation of Ground and Connected Aisle with the Influence of Sump-Pit Excavation in the Aisle
Authors: Yang Luming , Huang Jianhua , Wang Yunchen
Published: December 2019

The excavation of connected aisle is one of the key risks for the construction of subway in the coastal soft clay layer. The excavation of sump-pit will adversely affect the deformation of the ground and connected aisle, increase the risk of the project. The finite element software ABAQUS is used to carry out numerical simulation research on the excavation of sump-pit. The influence of deformation of ground and connected aisle were analyzed by the method of changing the position of sump-pit excavation. The result showed that: the most significant influence of sump-pit excavation was crown settlement, the second important influence was ground settlement, and the influence of headroom convergence was slight. The maximum ground settlement increased by 7% and the maximum crown settlement by 13% if the sump-pit was built in the middle of connected aisle.
Research on the Influence of The Vertical Compressive Static Load Test of The Pile by The Tidal Fluctuation
Authors: Tianyun Liu , Shuangshao LI
Published: December 2019

The settlement of pile top had risen continuously and stabilized difficulty during the vertical compressive static load test of single pile in the tidal fluctuation area. Based on the principle of effective stress, the phenomena can be explained that the reduction of soil effective stress caused by the rising tide level leaded to the decrease of the bearing capacity of the pile, and the reasonable suggestions are given to the designer of the pile foundation affected by the tidal fluctuation.
Study on hydro-mechanical coupling properties of clay rock in Tamusu - the pre-selected area of high-level radioactive waste repository
Authors: Liang Haian , Hu Qingbo , Wang Yu , Chen Haikang , Zhang Longpeng , Liu Chao
Published: December 2019

The research of hydro-mechanical coupling properties is of great significance for the design of high-level radioactive waste repository. In this paper, the permeability evolution test of Tamusu clay under full stress-strain condition is carried out. Based on the basic theoretical equation of hydro-mechanical coupling, the relationship between the permeability and stress of the Tamusu clay is analyzed. Combineed with the results of in-situ stress measurement in the Tamusu area, the excavation simulation of the roadway with a burial depth of 500 m in the area is carried out, and the change law of pore water pressure in the surrounding rock near the field is analyzed. The results show that when the osmotic pressure is constant, the peak strength increases and the permeability decreases with the increase of confining pressure. When the confining pressure is constant and osmotic pressure increases, the result is reversed; The permeability of Tamusu clay is affected by confining pressure more than the osmotic pressure, and the relationship between permeability and axial stress follows the negative exponential function.