bluuebunny/crossref_metadata_2025 huggingface dataset:
Original Romanian Research for a Rocket Engine with Multiple Combustion Chambers during 1940 - 1944
Authors: ZAGANESCU Nicolae-Florin , GHEORGHE Constantin-Marcian , KALMUTCHI Peter
Published: March 2020

The paper presents certain points of view regarding the history of Romanian rocket engines, during 1940-1944. Working independently of other scientists, during 1942 – 1944 the Romanian Nicolae Văideanu has invented and designed, independently of other researchers, a liquid fuel missile called UDOVILUL-V [3]. According to the design drawings, this missile was equipped with aerodynamically profiled propelling nozzles and was provided with a special alternator – distributor, the bypass valve adjusting the fuel components dosage in the two combustion chambers, in fuel tanks and pipes, while a special designed gas turbine was driving the centrifugal pumps and other mechanical equipment. Within his main patent the Romanian inventor has included the design of several components [2], [4], [5]. The technical solution of this outstanding design in rocketry development could provide 20kN thrust after 60 sec, enabling a speed of 3200 km/h [10].
Academician CAIUS IACOB – a Brilliant Mathematician Fascinated by Mechanics
Authors: ZAGANESCU Nicolae-Florin , ZAGANESCU Rodica , GHEORGHE Constantin-Marcian
Published: March 2020

The paper presents some interesting aspects related to the biography and works of Romanian mathematician Caius Iacob (1912–1992). He was famous for his works in the fields of mathematical analysis, fluid mechanics, classical hydrodynamics and compressible-flow theory. At the age of 19, he graduated from the Mathematics Faculty in Bucharest, and then he went to Paris to continue his studies at the Faculty of Sciences, where he worked on a PhD thesis under the advice of famous French mathematician Henri Villat. On 24 June 1935, Caius Iacob successfully presented to the Sorbonne committee his PhD thesis about “Determination of conjugated harmonic functions with some limit conditions, and their applications in hydrodynamics”. Returning to Romania, Caius Iacob had a long and successful career teaching mathematics and mechanics at the universities of Timişoara, Cluj and Bucharest. His most important work is considered the “Mathematical introduction to the mechanics of fluids”. This book, providing original ways to work with classical hydrodynamics and compressible-flow theory, was published in Romanian in 1952 and in French in 1959. In 1955, he was elected a Corresponding Member of the Romanian Academy, becoming a titular Member in 1963. He was also President of the Mathematics Section of the Romanian Academy from 1980 until the end of his life, in 1992. In 1991, he initiated the foundation of the “Romanian Academy Institute of Applied Mathematics”. In 2001 the institute merged with the “Centre for Mathematical Statistics”, which had been created in 1964 by mathematician Gheorghe Mihoc, thus creating the “Gheorghe Mihoc – Caius Iacob Institute of Mathematical Statistics and Applied Mathematics” of the Romanian Academy.
European Air C2 System National Requirements: Case Study of the Slovak Republic
Authors: ŽENTEK Miroslav , NEČAS Pavel
Published: March 2020

The end of the world bipolar division has reduced the likelihood of a threat of an atomic conflict, but at the same time it has released dormant conflicts. From that time, the phenomena that are not new, but their frequency, intensity, impact on human society have caused a change in the way they are perceived. In this context it is clear, that to ensure the sovereignty of the European airspace and specifically the one of the Slovak Republic, as a member of NATO, is the first priority task of the Air Force missions. To accomplish this, there will be significantly increased the requirements for processes automatization within Air C2 systems, in order to keep the necessary level of interoperability and to utilize and exploit both combat and reconnaissance unmanned aerial vehicles.
Experimental study on the formation and break-up of fluid bubbles
Authors: BOTTA Oana Daciana , MAGOS István , BALAN Corneliu
Published: March 2020

The study of fluid surfaces plays an important role in understanding the interfaces encountered in biological systems, as it allows for the investigation of the basic characteristics such as the formation, stability and permeability. Moreover, the adhesion and the fusion of biological membranes can be better understood by the experimental investigations of drops and bubbles formation in controlled dynamical processes. These studies have the potential to generate novel and value information for medical applications in the diagnosis and therapy using microfluidic-based biosensors and controlled drug-delivery micro-devices. In this paper, the dynamics of fluid interfaces have been studied experimentally and a method for determining the surface/interfacial tension is proposed. The analysis started with the investigation of the soap bubble formation and break-up. The rupture was triggered manually, by pinching the tip with a needle. The burst was recorded with high-speed cameras and the burst speed was determined. Furthermore, the thickness of the fluid membrane was approximated and the surface tension was calculated using the Culick-Taylor's law. The obtained values for the surface tension were in the same order of magnitude with that from the literature, thus, considering that the employed method can lead to adequate results. Subsequently, a set-up was created to automatically generate fluid bubbles, at different imposed flow rates. The spontaneous burst was analyzed for three different liquids: soap solution, vegetable oil and polyacrylamide. The phenomenon is characterized by the Ohnesorge number, which takes into account the influence of viscous forces in relation to the inertial and surface tension forces. For the soap bubbles, the obtained thickness of the membrane was in the range of (300-500) nm. The calculated surface tension was found to be 0.038 N/m. In the case of automatically generated fluid bubbles, the lowest Ohnesorge number was obtained for soap bubbles and the highest for oil bubbles. Moreover, soap bubbles had the highest break-up speed, while vegetable oil and polyacrylamide had lower and similar break-up speeds. The experimental study described in this paper is an alternative method for the identification of material parameters, such as density and surface tension, in a dynamical process. Numerical simulations are reported from the viewpoint of servo time constant performance.
An analytical method for simulation of centrifugal compressors
Authors: BREBENEL Marius
Published: March 2020

A pure analytical method for modeling and simulation of centrifugal compressors based on parametric analysis of governing equations is proposed. It will be shown that the main equations describing the compressor operation along with some new hypotheses allow to determine the most useful off-design characteristics of the machine for a given geometry and for given performances at design (nominal) regime. As example of application, a compressor map is determined along with other important features like surge and choke lines, optimal regimes line and constant efficiency curves (efficiency islands) without need of experimental data. The proposed method is intended for quick simulation of complex machines embedding centrifugal compressors, as an alternative of costly CFD analyses.
Static Analysis of Thin Plates: Bare and Stiffened
Authors: ISANAKA Bhargav Reddy ISANAKA , M Abdul Akbar , KUSHVAHA Vinod
Published: March 2020

Plates are being widely used for many structural applications such as aerospace, civil, electronic devices and marine industries etc. For these applications, it is important to know the plate behaviour under static loading condition. The present study focuses on filling the existing gap in the literature in order to know the plate behaviour of different geometrical shapes before and after adding the stiffener. A total of eight geometries namely circular, square, rectangular (with aspect ratio of 1.25, 1.50 and 1.75) and skew square (with 70o, 76.67o and 83.33o skew angles) were considered. Static analysis of considered geometries was carried out by using FEAST (a Finite Element software). To enable comparison of plates, three parameters namely the area of plates, starting point of the stiffener and curvature of the stiffener were kept constant. From the static analysis results, the effect of the curvilinear stiffener on different geometrical shapes, effect of aspect ratio on rectangular plates and effect of skew angle on skew square plates were given. The displacement of plates reduced significantly after adding the curvilinear stiffener to the bare plates and the stiffener was most effective in the case of circular plate. In the present study, the effect of aspect ratio and skew angle on static behaviour of bare and stiffened plates was also studied and discussed.
Aerodynamic Modelling of Unmanned Aerial System through Nonlinear Vortex Lattice Method, Computational Fluid Dynamics and Experimental Validation - Application to the UAS-S45 Bàlaam: Part 1.
Authors: KUITCHE Maxime Alex Junior , BOTEZ Ruxandra Mihaela , GUILLEMIN Arthur , COMMUNIER David
Published: March 2020

This paper describes a methodology to predict the aerodynamic behaviour of an Unmanned Aerial System. Aircraft design and flight dynamics modelling are mainly concerned with aerodynamics, and thus its estimation requires a high level of accuracy. The work presented here shows a new non-linear formulation of the classical Vortex Lattice Method and a comparison between this methodology and an experimental analysis. The new non-linear Vortex Lattice Method was performed by calculating the viscous forces from the strip theory, and the forces generated by the vortex rings from the vortex lifting law. The experimental analysis was performed on a reduced scale wing in a low speed wind tunnel. The obtained results were also compared to those obtained from semi-empirical methods programmed using DATCOM and our Fderivatives new in-house codes. The results have indicated the accuracy of the new formulation and showed that an aerodynamic model obtained with the aerodynamic coefficients predicted with this method could be useful for flight dynamics estimation.
Tree-topology-based quantum-key-relay strategy for secure multicast services
Authors: Dong Kai , Zhao Yongli , Yang Tiancheng , Li Yajie , Nag Avishek , Yu Xiaosong , Zhang Jie
Published: March 2020

Secure multicast services (SMSs), such as video conferences and multi-site backup of data centers, need to adopt multicast technology to transmit data among multiple parties with high demand for security. Quantum key distribution (QKD) is a promising technology for distributing information through theoretically secure secret keys. However, up to now, QKD has mainly focused on point-to-point distribution of quantum keys. In this study, what we believe to be a novel node structure is designed to support key multi-relay, and accordingly, a point-to-multipoint key relay scheme is put forward. An auxiliary topology is constructed to dynamically describe the connection and the weight between any two QKD nodes. Based on the auxiliary topology, a key-relay-tree-based routing-and-key assignment (KRT-RKA) algorithm is proposed and evaluated in static and dynamic scenarios. Simulation results show that the proposed algorithm has a higher security probability than the traditional scheme without a KR tree. Moreover, the performance of the KRT-RKA algorithm will be significantly improved as the number of destination nodes increases. In addition, the security of SMSs can be improved by increasing the density of the node distribution when KRT-RKA is applied.
On the limits of low-numerical-aperture imaging scatterometry
Authors: Wang Cai , Chen Xiuguo , Gu Honggang , Jiang Hao , Zhang Chuanwei , Liu Shiyuan
Published: March 2020

Although imaging scatterometry has been demonstrated to be a powerful technique for characterization of nano-gratings when high lateral resolution is required, some limits of this novel technique are still undisclosed yet, such as the constraint for the imaging numerical aperture (NA), the number of unit cells for accurate grating reconstruction, and the analyzability of image pixels associated with the grating region. To this end, we establish a vectorial image formation (VIF) model for imaging scatterometry based on the finite-difference time-domain (FDTD) method and vectorial diffraction theory. According to the established VIF model and the simulation results of a Si grating sample with finite numbers of unit cells, we find that accurate grating reconstruction by routine RCWA (rigorous coupled-wave analysis) -based data analysis requires an upper limit for the NA of the employed objective. And enough numbers of unit cells are also required to be covered in the illumination spot. Only in these conditions, the zeroth-order diffraction information of the grating under test can be exclusively and completely collected by the imaging system. Moreover, only the image pixels off the edge of the grating region are analyzable by routine RCWA-based data analysis due to the effect of edge scattering. The required number of grating unit cells and the size of the analyzable region are closely related with the imaging NA and the ratio between the illumination spot size and the size of the grating region D/L. Higher imaging NA or smaller D/L typically requires fewer grating unit cells and meanwhile allows a larger analyzable region. The investigation in this paper promises to provide valuable insights into the application of imaging scatterometry.
Design of double-slot antennas for terahertz array detectors in flip chip packaging
Authors: Xiao Peng , Tu Xuecou , Kang Lin , Li Zhenjie , Chen Pengfei , Zhou Shuyu , Jia Xiaoqing , Chen Jian , Wu Peiheng
Published: March 2020

In flip chip packaging, the performance of terahertz (THz) array detectors is directly influenced by the flip chip. In addition, predicting this effect is difficult because the readout circuits in the flip chip are very complex. In this study, to reduce the influence of the flip chip, we design a new type of double-slot antennas for THz array detectors. For comparison, we designed and analyzed dipole antennas with the same period. Numerical simulations showed that the coupling efficiency of the double-slot array antennas at approximately 0.6255 THz does not degrade, if the flip chip structure is changed. However, in the case of dipole array antennas with the same period of 250 µm, coupling efficiency was severely affected by the flip chip structure. These results revealed that double-slot antennas are more applicable to THz array detectors compared with dipole antennas, as they can more effectively reduce the influence of the flip chip. Furthermore, we integrated the double-slot antennas into Nb5N6 THz array detectors using the micro-fabrication technology. Measurement results indicated that double-slot antennas possess the advantages of facile preparation and large-scale integration, which provide great potential for THz array detectors in flip chip packaging.
Avaliação de Tradução
Authors: Da Silva Igor Antônio Lourenço
Published: March 2020

Edição completa.
A Theory of Mental Health and Monopoly Capitalism
Authors: Matthews David
Published: March 2020

As an exposition of capitalism's contradictions, Paul Baran and Paul Sweezy's Monopoly Capital remains one of the most influential treatises in Marxist political economy produced in North America. Among Baran and Sweezy's sociological investigations, they identified the negative consequences of capitalism for mental health, drawing attention to the manner in which the organization of capitalist society conflicted with the essential needs of the individual.
The Quality of Monopoly Capitalist Society: Mental Health
Authors: Baran Paul A. , Sweezy Paul M.
Published: March 2020

When Paul Baran and Paul Sweezy's Monopoly Capital was published by Monthly Review Press in 1966, two of the chapters originally drafted for the book were left out of the final volume: what was to have been Chapter 9 in the original plan for the book, entitled "Some Theoretical Implications," and what was intended as Chapter 11, "The Quality of Monopoly Capitalist Society: Culture and Mental Health." In July–August 2012, "Some Theoretical Implications" was finally published in Monthly Review. This was followed by the publication of the first part, approximately two-thirds of the whole, of "The Quality of Monopoly Capitalist Society: Culture and Mental Health," titled "The Quality of Monopoly Capitalist Society: Culture and Communications," in the July–August 2013 issue of the magazine. The section on mental health was left out on the grounds that it was incomplete. We finally publish it here.
TOWARDS DIGITIZING THE CONSTRUCTION INDUSTRY: STATE OF THE ART OF CONSTRUCTION 4.0
Authors: Hossain Md Aslam , Nadeem Abid
Published: March 2020

Having a significant economic impact in country's GDP and being a major workforce, construction industry is yet characterized by low production rate, low technological advancement, minimum automation and robotic usage, and so on. With the visionary idea of Industry 4.0 that focuses on digitization of the value chain of a product and improving productivity through a variety of technologies and automated manufacturing environment, this research aims to develop a framework to adopt Construction 4.0 within a construction company. Current state of the art of the technologies in construction associated with the notion of Industry 4.0 (e.g., Building Information Modelling, virtual reality, augmented reality, Drone, etc.) is explored through extensive literature studies. The proposed framework incorporates current technological advancement related to construction industry, legislative requirements, barriers, enterprise transformation requirements and so on. Construction 4.0 would make a great impact in construction industry through improved value chain of construction projects, productivity improvement, and safe and sustainable construction. Indeed, the proposed framework would contribute to the advancement of new knowledge in the worlds' construction companies and provide potentials of new research focuses.
GREEN ROOFS TO IMPROVE THE ENERGY RENOVATION RESILIENCE OF HISTORIC BUILDINGS
Authors: Santi Giovanni , Battini Sara
Published: March 2020

The introduction of vegetation in urban areas, through both green roofs and green walls, is a sustainable strategy for improving the environment and the quality of life, as well as crucial for urban biodiversity since the moment it is able to create new habitats for plant and animal species. The design and realization of green roof systems abroad is promoted and stimulated while in Italy, this subject, is still an innovation not supported by many real implementations. The application of this technological green system has a great importance for the redevelopment of existing building heritage, especially for historic buildings, to improve their energy-performance qualities, with respect for their architectural value. The aim of this study is to identify the technical issues for the realization of green roofs in urbanized contexts by focusing on the implementation of a green roof on a building of Leghorn following intervention guidelines developed. This research shows that not only does this system allow higher energy saving, but it also brings a decrease of load bearing on the structure.
INTEGRATING BUILDING INFORMATION MODELING AND VISUAL PROGRAMMING FOR BUILDING LIFE-CYCLE COST ANALYSIS
Authors: Likhitruangsilp Veerasak , Le Hang T. T. , Yabuki Nobuyoshi , Ioannou Photios G.
Published: March 2020

In recent years, the fierce competition in worldwide real-estate market has pushed the stakeholders towards the sustainability for buildings. Life-cycle cost (LCC) is an effective economic evaluation tool that provides a detailed account for all costs related to constructing, operating, maintaining, and disposing a construction project over a defined period of time. Awareness of better value of money throughout the LCC is beyond the initial price. Governments and Contracting authorities add the LCC as a key provision in the context of National Codes and Council Directives to promote the growth of sustainability concept. Current LCC analytical methods are costly, laborious, and time-consuming due to the difficulties of obtaining information and implementing many single LCC analyses for all building elements, which may be attributed to the inaccuracy of results. Building information modeling (BIM) is a modern technology that can potentially overcome the asperities that obstruct practical LCC implementation. This paper develops a new automated system for performing LCC analyses for new building projects by integrating BIM authoring programming with visual programming. The proposed system consists of two main modules. The BIM module is designed to retrieve 3D geometric and physical parameters of building element types. The life-cycle cost calculation module can perform automatic estimating and report results. This system provides an economic evaluation tool for the owner to manage the total life-cycle budget of their projects.
La identidad de las educadoras diferenciales en tiempos de políticas de accountability
Authors: Inostroza Fabián A.
Published: March 2020

El objetivo principal de esta investigación es comprender la construcción de la identidad de las educadoras diferenciales en el marco de la implementación de políticas educativas de rendición de cuentas o accountability en Chile. Metodológicamente este estudio responde a la tradición cualitativa de investigación, en el que participaron 10 educadoras diferenciales de la Región Metropolitana. Los instrumentos para producir la información en esta investigación corresponden a la entrevista en profundidad y la bitácora reflexiva. Como técnica de análisis de las narrativas se procedió a emplear el análisis de contenido cualitativo. Entre los principales hallazgos se encuentran una construcción de identidad en transformación y tensionada por las demandas de la rendición de cuentas y la producción de prácticas de estandarización y exclusión como efectos de las lógicas de mercado educativo, las que van en contra de la identidad que históricamente han construido estas educadoras.
Preservice teachers’ beliefs about high-stakes testing and their working environments
Authors: Nichols Sharon L. , Brewington Shon
Published: March 2020

In this exploratory mixed methods survey study, we assess preservice teachers’ (n=379) experiences with and beliefs about their high-stakes testing experiences and analyze how they relate to their beliefs about the role and efficacy of high-stakes testing in education and their future profession. Using Likert, vignette, and open-ended response opportunities, we gauged preservice teachers’ beliefs about accountability and the role of high-stakes testing in three ways: (a) what are their personal experiences with high-stakes testing, (b) what are their their beliefs about accountability and high-stakes testing in general, and (c) what role does accountability (and testing pressures) play in their future workplace preferences? Results indicate that preservice teachers’ experiences with and beliefs about high-stakes testing accountability vary based on gender, ethnicity, and previous experiences with high-stakes tests. Importantly, although in aggregate our participants reported they generally disliked the high-stakes tests they personally had to take in high school, subgroup analyses reveal that for those who took them during the NCLB era, they also saw high-stakes tests as good thing for education overall. Preservice teachers who were younger and “grew up” under NCLB and the height of high-stakes testing believed high-stakes tests to be a waste of time for them personally, but a useful way to evaluate teachers as an educational policy. Vignette and qualitative analyses of workplace preferences and rationales underscore some of the assumptions our preservice teachers hold about high-stakes testing as a policy mechanism to help explain this finding. We conclude with implications for policy and future research.
The contributions of wild tree resources to food and nutrition security in sub-Saharan African drylands: a review of the pathways and beneficiaries
Authors: Koffi C.K. , Lourme-Ruiz A. , Djoudi H. , Bouquet E. , Dury S. , Gautier D.
Published: March 2020

Wild tree resources are known to play an important role in local stakeholders' livelihoods particularly in the food and nutrition security of people living in semi-arid sub-Saharan Africa. Based on a comprehensive review of the literature, this article examines the relative importance
of the contributions of tree resources to food and nutrition security for rural households, while considering alternative causal pathways. The main conclusions of the review are that most studies provide useful evidence on specific contributions of tree products to food and nutritional security,
and for whom. However, detailed data on the actual contribution of tree products are still lacking. In addition, we argue that the concept of access as a pillar of food security is not sophisticated enough to understand the landscape dynamics and the socio-economic relations at the nexus of
food security and rights of access. Links are needed to better understand the underlying processes in the definition of each stakeholder's rights of access to tree resources in a context of rapidly changing landscapes, and how income generated by tree resources contributes to food and nutrition
security. An approach to food security based on rights of access would advance our understanding of their use and tackle the root causes of food deficiency based on different social groups. In light of current patterns of access to tree food for different stakeholders, including women and
children, an intersectional approach that accounts for age, gender, ethnicity and wealth would benefit food security research by a more targeted and discerning approach to existing rights of access and to the roles of different community members.
To translanguage or not to translanguage: Ideology, practice, and intersectional identities
Authors: Nagashima Yuzuko , Lawrence Luke
Published: March 2020

Translanguaging is an emerging research area within applied linguistics that blurs the lines between named languages used by bi- and multilingual language users and considers all languages to be part of the individual’s single semiotic repertoire. In parallel with this emergence, issues surrounding language teacher identities and emotion labor have also become prominent sites of research in applied linguistics. In this paper we adopt a unique two-stage qualitative research approach involving aspects of narrative knowledging and duoethnography in order to investigate the challenges and obstacles faced by teachers of English in implementing translanguaging practices in their personal and professional lives. By using intersectionality as an analytical tool, we found that the challenges to making use of translanguaging practices were intimately and intricately linked with personal identities and social context. The results suggest that decisions surrounding translanguaging practices can be seen as context-dependent, discursively produced constructions, rather than the cut and dried options that they have been presented as in previous literature.
Overstandin: Upscaling reading positions and rescaling texts/signs
Authors: Singh Jaspal Naveel
Published: March 2020

Overstandin occurs when languagers upscale their reading positions to rescale the meanings of texts or signs according to their own intentions. While understanding is an important faculty for languagers and a central analytical category for applied linguistics research, it cannot fully grasp agency and creativity in complex languaging in postcolonial worlds. By focusing on processes of overstandin, this article shows how languagers assume an upscaled reading position from which they find opportunities to attack the form and function of a text/sign. Thereby they can destabilise the indexical equilibrium of a sign and show up the ambivalence of language. Understanding often erases this ambivalence. For this reason, the exposure of ambivalence through overstandin can be emancipative, especially in postcolonial thinking. I further argue that overstandin is emphasised in the dream-state – both conceptualised as a state of relative unconscious experiencing and a wish, desire, aspiration for an emancipated future. In the dream-state the signifier stands over the signified. Such processes of overstandin pose challenges to applied linguistics, which continues to rely on wake-state understanding as a central analytical category for its gaze and its methods and thereby reproduces hegemonic knowledge-power structures that have been put in place during Enlightenment, colonialism and current global modernities. This article suggests that an account of processes of overstandin as an agentive meaning-making of the epistemic hinterlands of the postcolonial, could rehabilitate ambivalence as an anthropological category for our discipline. My detour via dream-states is merely a rhetoric of the argument presented here and it should not be assumed that I suggest that applied linguists have to turn to mysticism or dream analysis in order to account for overstandin, scaling and indexical ambivalence. The oneiric rhetoric itself is an overstandin, which aims to challenge common-sense empiricism in our discipline.
Interactional regimes of sociolinguistic behaviour: An ethnographic exploration of the scales at play across the spaces of an asylum-seeking centre
Authors: Spotti Massimiliano
Published: March 2020

Drawing on the notion of sociolinguistic scaling, the present contribution argues for an understanding of an asylum-seeking centre as a unit of inquiry in which sociolinguistic repertoires are played out during intercultural communicative encounters. The contribution shows how the centre’s spaces encapsulate time- and space-bound interactional regimes and language hierarchies. Taken as such, the different rooms that make up the centre, e. g. the office, the activity room and the corridor, all may seem neutral spaces where the daily lives of people unfold. However, each of these spaces invites, allows and dismisses various interactional sociolinguistic regimes that lead to micro-practices of inclusion and exclusion. The article concludes with a consideration on whether the homogeneous category ‘newly arrived migrant in need of civic integration’ authored by many governments across Europe, should not be re-evaluated, in light of the affordances of sociolinguistic scaling and digital literacy potentials that each of these newly arrived individuals have in stock in their repertoires.
The Economics of Enlightenment: Time Value of Knowledge and the Net Present Value (NPV) of Knowledge Machines, A Proposed Approach Adapted from Finance
Authors: Kashyap Ravi
Published: March 2020

We formulate one methodology to put a value or price on knowledge using well accepted techniques from finance. We provide justifications for these finance principles based on the limitations of the physical world we live in. We start with the intuition for our method to value knowledge and then formalize this idea with a series of axioms and models. To the best of our knowledge this is the first recorded attempt to put a numerical value on knowledge. The implications of this valuation exercise, which places a high premium on any piece of knowledge, are to ensure that participants in any knowledge system are better trained to notice the knowledge available from any source. Just because someone does not see a connection does not mean that there is no connection. We need to try harder and be more open to acknowledging the smallest piece of new knowledge that might have been brought to light by anyone from anywhere about anything.
Animal fat and glycerol bioconversion to polyhydroxyalkanoate by produced water bacteria
Authors: Sohail Rafeya , Jamil Nazia , Ali Iftikhar , Munir Sajida
Published: March 2020

Oil reservoirs contain large amounts of hydrocarbon rich produced water, trapped in underground channels. Focus of this study was isolation of PHA producers from produced water concomitant with optimization of production using animal fat and glycerol as carbon source. Bacterial strains were identified as Bacillus subtilis (PWA), Pseudomonas aeruginosa (PWC), Bacillus tequilensis (PWF), and Bacillus safensis (PWG) based on 16S rRNA gene sequencing. Similar amounts of PHA were obtained using animal fat and glycerol in comparison to glucose. After 24 h, high PHA production on glycerol and animal fat was shown by strain PWC (5.2 g/ L, 6.9 g/ L) and strain PWF (12.4 g/ L, 14.2 g/ L) among all test strains. FTIR analysis of PHA showed 3-hydroxybutyrate units. The capability to produce PHA in the strains was corroborated by PhaC synthase gene sequencing. Focus of future studies can be the use of lipids and glycerol on industrial scale.
A Framework for Designing Business-Acceleration Programs: A Case Study from Egypt
Authors: Ismail Ayman
Published: March 2020

Business acceleration services are gaining popularity around the world. In this study, we put forward a framework and an iterative process for the design of acceleration programs. Based on literature from around the world and a case study of an acceleration program in Egypt, we develop a model that considers the process for designing, monitoring, and adjusting an acceleration program based on both internal and external considerations. In this study, we find that aspects such as the analysis of the external environment in the surrounding entrepreneurship ecosystem, and of the internal environment in the host institution’s capabilities, resources, and limitations, are important in guiding the design process. We also illustrate a comprehensive set of design parameters to be considered in the development of the acceleration program, including the program’s value proposition, sector focus, duration, service offering, resource intensity, partnerships, as well as the profile of the startups supported. In presenting this model, we aim to fill an important gap in research on how accelerators are designed and offer a framework substantiated by academic review that helps practitioners and policymakers avoid “copying and pasting” acceleration programs without careful attention to the local contexts and needs.
Investigation of the role of β-TrCP in growth hormone transduction defect (GHTD)
Authors: Kostopoulou Eirini , Rojas Gil Andrea Paola , Spiliotis Bessie E.
Published: March 2020

Background

Growth hormone(GH) and epidermal growth factor (EGF) stimulate cell growth and differentiation, and crosstalking between their signaling pathways is important for normal cellular development. Growth hormone transduction defect (GHTD) is characterized by excessive GH receptor (GHR) degradation, due to over-expression of the E3 ubiquitin ligase, cytokine inducible SH2-containing protein (CIS). GH induction of GHTD fibroblasts after silencing of messenger RNA (mRNA) CIS (siCIS) or with higher doses of GH restores normal GH signaling. β-Transducing-repeat-containing protein (β-TrCP), another E3 ubiquitin ligase, also plays a role in GHR endocytosis. We studied the role of β-TrCP in the regulation of the GH/GHR and EGF/EGF receptor (EGFR) pathways in normal and GHTD fibroblasts.

Materials and methods

Fibroblast cultures were developed from gingival biopsies of a GHTD (P) and a control child (C). Protein expression and cellular localization of β-TrCP were studied by Western immunoblotting and immunofluorescence, respectively, after: (1) GH 200 μg/L human GH (hGH) induction, either with or without silence CIS (siCIS), and (2) inductions with 200 μg/L GH or 1000 μg/L GH or 50 ng/mL EGF.

Results

After induction with: (1) GH200/siCIS, the protein expression and cytoplasmic-membrane localization of β-TrCP were increased in the patient, (2) GH200 in the control and GH1000 in the patient, the protein and cytoplasmic-membrane localization of β-TrCP were increased and (3) EGF, the protein expression and cytoplasmic-membrane localization of β-TrCP were increased in both the control and the patient.

Conclusions

(1) β-TrCP appears to be part of the negative regulatory mechanism of the GH/GHR and EGF/EGFR pathways. (2) There appears to be a negative correlation between β-TrCP and CIS. (3) In the control and GHTD patient, β-TrCP increases when CIS is suppressed, possibly as a compensatory inhibitor of the GH/GHR pathway.
3-Iodothyronamine and 3,5,3′-triiodo-L-thyronine reduce SIRT1 protein expression in the HepG2 cell line
Authors: Sacripanti Ginevra , Lorenzini Leonardo , Bandini Lavinia , Frascarelli Sabina , Zucchi Riccardo , Ghelardoni Sandra
Published: March 2020

Background

3-Iodothyronamine (T1AM) is an endogenous messenger chemically related to thyroid hormone. Recent results indicate significant transcriptional effects of chronic T1AM administration involving the protein family of sirtuins, which regulate important metabolic pathways and tumor progression. Therefore, the aim of this work was to compare the effect of exogenous T1AM and 3,5,3′-triiodo-L-thyronine (T3) chronic treatment on mammalian sirtuin expression in hepatocellular carcinoma cells (HepG2) and in primary rat hepatocytes at micromolar concentrations.

Materials and methods

Sirtuin (SIRT) activity and expression were determined using a colorimetric assay and Western blot analysis, respectively, in cells treated for 24 h with 1–20 μM T1AM or T3. In addition, cell viability was evaluated by the MTTtest upon 24 h of treatment with 0.1–20 μM T1AM or T3.

Results

In HepG2, T1AM significantly reduced SIRT 1 (20 μM) and SIRT4 (10–20 μM) protein expression, while T3 strongly decreased the expression of SIRT1 (20 μM) and SIRT2 (any tested concentration). In primary rat hepatocytes, T3 decreased SIRT2 expression and cellular nicotinamide adenine dinucleotide (NAD) concentration, while on sirtuin activity it showed opposite effects, depending on the evaluated cell fraction. The extent of MTT staining was moderately but significantly reduced by T1AM, particularly in HepG2 cells, whereas T3 reduced cell viability only in the tumor cell line.

Conclusions

T1AM and T3 downregulated the expression of sirtuins, mainly SIRT1, in hepatocytes, albeit in different ways. Differences in mechanisms are only observational, and further investigations are required to highlight the potential role of T1AM and T3 in modulating sirtuin expression and, therefore, in regulating cell cycle or tumorigenesis.
The effects of follicle-stimulating hormone receptor (FSHR) -29 and Ser680Asn polymorphisms in IVF/ICSI
Authors: Paschalidou Chrysa , Anagnostou Elli , Mavrogianni Despoina , Raouasnte Rami , Klimis Nikiforos , Drakakis Peter , Loutradis Dimitrios
Published: March 2020

Background

The aim of this study was to analyze two different polymorphisms, Ser680Asn and -29 (G>A) promoter polymorphism, of the follicle-stimulating hormone receptor (FSHR) gene, individually but also in combination, in a sample of Greek women undergoing in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI).

Materials and methods

One hundred and forty-one women undergoing IVF or ICSI and 94 controls were genotyped by real-time polymerase chain reaction (RT-PCR) for the two FSHR polymorphisms. The association of the alleles with the clinical, biochemical and other parameters concerning the controlled ovarian stimulation (COS) protocol and outcome was investigated, as well as the pregnancy rate.

Results

The study of each polymorphism individually revealed a positive correlation of the SerSer genotype (Ser680Asn polymorphism) with higher luteinizing hormone (LH) levels on the third day of the menstrual cycle. On the other hand, the A allele for the -29 (G>A) promoter polymorphism correlated with the increased number and quality of cumulus-oocyte complexes (COCs). No differences were detected when the different genotypes of the two polymorphisms were combined – the population study was grouped according to the number of polymorphic alleles they carried (0–4 alleles). Women who presented all polymorphic alleles, AsnAsn/AA, exhibited the lowest LH levels (2.62 ± 0.68 mIU/L), but were rarely detected (n = 2, 1.4% of the studied population).

Conclusions

The data from this study reflect that the investigation of the combination of polymorphisms, such as FSHR -29 and Ser680Asn, could offer a valuable tool in order to evaluate and anticipate the outcome of the ovulation induction protocols, especially in the group of patients with failed attempts.
Safety, influence on the endometrium, sonographic changes and bleeding profile after 13 cycles with the new drospirenone only pill (DOP) for contraception
Authors: Regidor Pedro-Antonio , Colli Enrico , Georgiev Dimitar , Koytchev Rossen , Richter Wolfram
Published: March 2020

Background

The primary objective of the present trial was to assess the endometrial safety of a new oral contraceptive containing 4 mg drospirenone for a total duration of 13 cycles of 28 days each: 24 days of active treatment followed by 4 days placebo treatment per treatment cycle.

Materials and methods

This was a single-center, open-label, multiple-dose study on healthy female subjects at risk of pregnancy. Twenty one (= safety population set) pre-menopausal female Caucasian subjects started treatment with the study medication. The mean age was 29.0 years (range 19.0–36.0 years). Four subjects terminated the trial prematurely for the following reasons: on the subject’s request (n=2), due to an adverse event (n=1) and due to loss of contact (n=1). Seventeen subjects completed the planned duration of 13 cycles of open treatment with the test product (each cycle of 28 days).

Results

At visit 1 (pre-treatment), the biopsy result in the safety population set was proliferative in 14 cases and secretory in seven cases. At visit 7, four cases showed an inadequate result (insufficient tissue for diagnosis), 12 as proliferative and three as secretory. The number of biopsies with proliferative and secretory results reduced under treatment (safety population). The pre-post treatment changes in the endometrial biopsy results in the treatment completers set (n=17) showed almost no differences. At visit 1 (pre-treatment), the biopsy result was proliferative in 12 cases and secretory in five cases. At visit 7 (after 13 cycles of 28 days), four cases showed an inadequate result (insufficient tissue for diagnosis), 11 as proliferative, and two as secretory. The mean endometrial thickness in the safety population was reduced from 8.3 mm at visit 1 to 6.0 mm at visit 7. When comparing the endometrial thickness in the 21 subjects (safety population), the endometrial thickness showed a pre-post difference of 2.1 mm, whereas the endometrial thickness in the 17 study completers showed a pre-post difference of 2.5 mm (8.2 mm at visit 1–5.6 mm at visit 7).

Conclusions

Drospirenone 4 mg film-coated tablet in a dosage regime of 24/4 days is, regarding endometrial histology, a safe drug. Trial registration: EudraCT Register number: 2013-002300-13.
Numerical Study of the Movement of Water Surface of Dam Break Flow by VOF Methods for Various Obstacles
Authors: Issakhov Alibek , Imanberdiyeva Medina
Published: March 2020

In this paper, the movement of the water surface is numerically simulated when a dam is broken by the volume of fluid (VOF) method. The mathematical model is based on the Navier–Stokes equations and uses the large eddy simulation turbulent model, describing the flow of an incompressible viscous fluid and the equation for the phase. These equations are discretized by the finite-volume method. Numerical PISO (Pressure-Implicit with Splitting of Operators) algorithm was chosen for numerical solution of this equation system. The movement of the water surface is captured by using the VOF method, which leads to a strict mass conservation law. The accuracy of the three-dimensional model and the chosen numerical algorithm were tested using several laboratory experiments on dam break problem. In each of the problems, the obtained results were compared with the experimental data and several calculations by other authors and in each of the test problems, the developed model showed results close to the experimental data. Comparison of simulation results with experimental data for various turbulent models was also performed. And also two combined problems were performed which are more close to real conditions; with the help of these problems, flooding zones and flooding time were identified that would help in evacuating people from dangerous zones.
Rational Type Inequality with Applications to Voltera–Hammerstein Nonlinear Integral Equations
Authors: Sarwar Muhammad , Bahadur Zada Mian , Radenović Stojan
Published: March 2020

The aim of this work is to establish fixed point theorems under rational type contractions in the framework of complex-valued metric spaces. These theorems extend and generalize some prominent results in the present literature. Furthermore, as an application the existence result is given for the system of Volterra–Hammerstein non-linear integral equations.
Measure-Valued Solutions to a Non-Strictly Hyperbolic System with Delta-Type Riemann Initial Data
Authors: Li Shuangrong , Shen Chun
Published: March 2020

This paper is concerned with the construction of global measure-valued solutions to the extended Riemann problem for a non-strictly hyperbolic system of two conservation laws with delta-type initial data. The wave interaction problems have been extensively studied for all kinds of situations by using the initial condition consisting of constant states in three pieces instead of delta-type initial data under the perturbation method. The measure-valued solutions of the extended Riemann problem are achieved constructively when the perturbed parameter tends to zero. During the process of constructing solutions, a new and interesting nonlinear phenomenon is discovered, in which the initial Dirac delta function travels along the trajectory of either delta shock wave or contact discontinuity (or delta contact discontinuity). Moreover, a delta shock wave is separated into a delta contact discontinuity and a shock wave during the process of delta shock wave penetrating a composite wave composed of a rarefaction wave and a contact discontinuity. In addition, we further consider the constructions of global measure-valued solutions when the initial condition contains Dirac delta functions at two different initial points.
Optimization frameworks for machine learning: Examples and case study
Authors: Giesen Joachim , Laue Sören , Mitterreiter Matthias
Published: March 2020

Mathematical optimization is at the algorithmic core of machine learning. Almost any known algorithm for solving mathematical optimization problems has been applied in machine learning and the machine learning community itself is actively designing and implementing new algorithms for specific problems. These implementations have to be made available to machine learning practitioners which is mostly accomplished by distributing them as standalone software. Successful well-engineered implementations are collected in machine learning toolboxes that provide a more uniform access to the different solvers. A disadvantage of the toolbox approach is a lack of flexibility as toolboxes only provide access to a fixed set of machine learning models that cannot be modified. This can be a problem for the typical machine learning workflow that iterates the process of modeling, solving and validating. If a model does not perform well on validation data, it needs to be modified. In most cases these modifications require a new solver for the entailed optimization problems. Optimization frameworks that combine a modeling language for specifying optimization problems with a solver are better suited to the iterative workflow since they allow to address large problem classes. Here, we provide examples of the use of optimization frameworks in machine learning. We also illustrate the use of one such framework in a case study that follows the typical machine learning workflow.