Miracle-dz/UniFAR-FTUs huggingface dataset:
The rheological anomaly in water-silicate systems: a possible thermodynamic explanation

A rheological anomaly, consisting in the reversible increase in solution viscosity with increasing temperature, is a typical property of aqueous solutions of aminosilicates (polysilicates of aliphatic amines, amino alcohols and other amino compounds). To explain this anomaly, a simple mathematical model of interrelated acid-base and polycondesation equilibria in such solutions is proposed. The proposed calculation model assumes a direct dependence of the solution viscosity on the polymerization degree of silicate anions, as well as the independence of the dissociation constant of silanols and the polycondensation equilibrium constant on the degree of anions polymerization. Based on the assumptions made, a system of eight linear and nonlinear equations was constructed and solved. The results of calculations performed for concentrated solutions of aminosilicates (methylamine and piperidine silicates), as well as sodium and tetramethylammonium silicates, confirm the presence of a positive temperature dependence of the polymerization degree of silicate anions in the aminosilicate solutions, in contrast to the solutions of silicates of the strong bases. Thus, the proposed mathematical model of polymerization-hydrolysis equilibria in aqueous silicate solutions qualitatively explains the existence of the rheological anomaly in aqueous solutions of aminosilicates and its absence in solutions of alkali silicates and silicates of quaternary ammonium bases. In addition, this model correctly reproduces the displacements of the molecular mass distribution of silicate anions with changes in chemical composition and concentration of solutions. The proposed approach makes it possible to clarify the mechanism of the rheological anomaly, to understand the roles of various thermodynamic factors in its occurrence, and, as a consequence, to conduct a more meaningful search for new silicate and non-silicate systems with the same anomaly.
Coupling effects in array‐fed reflector antennas with digital beamforming

Sigurd Huber, Microwaves and Radar Institute, German Aerospace Center (DLR), Oberpfaffenhofen, Germany. Email: sigurd.huber@dlr.de Abstract Many modern microwave systems, for example, in the field of satellite communications, remote sensing for Earth observation or radio astronomy, employ reflector antennas with beam‐shaping capabilities. A generalised description of multi‐channel receiver architectures with digital beamforming, employing scattering parameter formalism is presented here. Special emphasis has been placed on noise modelling, where noise sources have been included also at the input ports of the receive amplifiers. The performance of such a system is evaluated in terms of the signal‐to‐noise ratio (SNR) and the signal‐to‐ interference ratio at the beamformer output. The basis for this analysis is a design example of a reflector antenna fed by a linear patch array, whose S‐parameters have been computed by means of electromagnetic simulations. In this work, two scenarios are addressed. In the first case, the effect of coupling has been neglected in the derivation of the beamforming weights. The main consequence appears to be a severely impaired interference suppression performance. In the second scenario, which has not been addressed in the literature so far, noise from the input ports of the receive amplifiers couple via the antenna radiators and can result in a loss of SNR at the beamformer output if neglected in the beamforming process.
Does firms’ CSR engagement support tourism sector development? Moderation effect of CSR committee and CEO duality

The study tests whether the hospitality and tourism (H&T) sector’s corporate social responsibility (CSR) engagement supports tourism sector development and investigates whether CSR committee and CEO duality moderate this relationship. The data was retrieved from the Thomson Reuters Eikon and the World Bank databases covering the years between 2002 and 2019, and Fixed-Effects panel data regression analysis was executed. The results show that the environmental and social performance of H&T firms improves tourist arrivals and tourism receipts. Moreover, the first moderation analysis showed that CSR committees’ existence makes a significant difference in connecting only environmental practices to the tourism sector development. The second moderation analysis indicated that CEO duality moderates the association between CSR performance and the tourism sector development depending on the CSR dimension. While moderation does not exist for environmental indicators, it exists for social and governance indicators. The findings suggest several theoretical and practical implications for H&T firms and associated governmental and nongovernmental organizations.
Diospyros assimilis root extract assisted biosynthesised silver nanoparticles and their evaluation of antimicrobial activity

The current research study focuses on biosynthesis of silver nanoparticles (Ag NPs) for the first time from silver acetate employing methanolic root extract of Diospyros assimilis. The UV–Vis absorption spectrum of biologically synthesised nanoparticles displayed a surface plasmon peak at 428 nm indicating the formation of Ag NPs. The influence of metal ion concentration, reaction time and amount of root extract in forming Ag NPs by microscopic and spectral analysis was thoroughly investigated. Structural analysis from transmission electron microscopy confirmed the nature of metallic silver as face-centered cubic (FCC) crystalline with an average diameter of 17 nm, which correlates with an average crystallite size (19 nm) calculated from X-ray diffraction analysis. Further, the work was extended for the preliminary examination of antimicrobial activity of biologically synthesised Ag NPs that displayed promising activity against all the tested pathogenic strains.
Structure of triplite LiFeSO4F powder synthesized through an ambient two-step solid-state route

The triplite LiFeSO4F displays both the highest potential ever reported for an Fe-based compound, as well as a comparable specific energy with that of popular LiFePO4. The synthesis is still a challenge because the present approaches are connected with long time, special equipments or organic reagents, etc. In this work, the triplite LiFeSO4F powder was synthesized through an ambient two-step solid-state route. The reaction process and phase purity were analyzed, coupled with structure refinement and electrochemical test.
Syphilis on the rise-a retrospective study at a tertiary care hospital in Northeast India

Background: Syphilis is an important sexually transmitted disease known for quite a long time. Its recognition and efficient treatment have become all the more necessary in the era of HIV epidemic in many clinical situations.Methods: A retrospective observational study of 7 years (January 2013 to December 2019) in 43 patients of confirmed syphilis attending regional institute of medical sciences (RIMS), Imphal.Results: During 7-year study period a sharp rise in syphilis cases were present from 2018 till the end of the study. Out of 43 patients, 39 were males. The most common age group was 25-40 years. Half of them were married. Maximum were heterosexuals and only 8 were homosexuals. Premarital and extra marital exposures were seen in 18 and 3 patients respectively. Patients presented in different forms-primary (48.6%), latent (25.7%) and secondary syphilis (22.8%). No cases of congenital syphilis and neurosyphilis were seen. VDRL titres ranged from 1:4 to 1:32. Six patients had HIV co-infection. No atypical presentations were seen.Conclusions: Increasing cases of syphilis have been observed in recent years. Syphilis screening and prompt treatment amongst risk groups have become crucial along with proper surveillance and public health measures to prevent disease transmission.
Variance‐constrained resilient H∞ filtering for mobile robot localization under dynamic event‐triggered communication mechanism

This paper is concerned with the mobile robot localization problem subject to filter gain uncertainty under dynamic event‐triggered communication mechanism, and meanwhile, the H∞ filtering performance and the error variance constraint are guaranteed. For saving the sensor energy, a dynamic event‐triggered communication mechanism is introduced to manage the transmission of the measurement data from the sensor to the filter. To characterize the possible fluctuations of the desired filter gain, a resilient filter is constructed for the mobile robot localization. The aim of this paper is to find a solution to the mobile robot localization problem by designing a nonlinear resilient filter such that the filtering error dynamics satisfies both the H∞ performance requirement and the error variance constraint over a finite time horizon simultaneously. By resorting to the Lyapunov theory and the stochastic analysis technique, the sufficient conditions are established to guarantee that the error dynamic system satisfies both the H∞ performance requirement and the error variance constraint. Then, a recursive linear matrix inequality (RLMI) approach is employed to design the desired filter. Based on the proposed filter design scheme, the corresponding localization algorithm is presented. Finally, an experiment is conducted in the simulation environment to verify the effectiveness of the proposed localization algorithm.
Individual variation influences avoidance behaviour of invasive common carp (Cyprinus carpio) and native buffalo (Ictiobus) to stroboscopic and acoustic deterrents

Uncontrolled biological invasions are reducing freshwater ecosystem diversity and resilience. Research is needed to evaluate whether non-structural deterrents are feasible within lock or canal environments. This study examined common carp (Cyprinus carpio) and buffalo hybrid (Ictiobus) movement patterns in response to acoustic and stroboscopic deterrents. Twelve strobe lights and one underwater speaker were deployed across the centre of a ship slip, with an environment analogous to a navigation canal. Common carp (n=6) and Ictiobus (n=4) were implanted with acoustic telemetry tags, and their behaviours were examined under control, stroboscopic, and acoustic stimuli for 60-min trial periods. Trials were run during the day and night for six straight days. Linear models determined that the stroboscopic and acoustic stimuli altered fish positioning within the ship slip, but produced weaker avoidance responses than those observed elsewhere. Weak responses were likely due to a strong preference for the open end of the ship slip and a lack of acoustic refuge during the acoustic treatment. Avoidance responses also differed widely among individuals of the same species, with fish expressing repeatability of avoidance radius size across trials. Ambient and stimulus sound-pressure levels should be carefully considered when deploying acoustic deterrents.
Co-creation of an Acceptable Indigenous Food Diet for Children Under Five in Early Childhood Development Centres

Background: The use of indigenous food (IF) such as green leafy vegetables and fruits in rural communities has been the main source of food despite being replaced by food high in sugar and fats. Early Childhood Development (ECD) centres are uniquely positioned for positive influence to healthy eating of children. The aim of this study was for ECD stakeholders to co-create an IF diet for children under five in ECD centres.Method: A sequential explanatory mixed method design was employed. We conducted focus group discussion with stakeholders employing the community-based participatory research (CBPR) approach and the nominal group technique ranking method to co-create to an acceptable indigenous food diet for children. Data was analyzed using both qualitative and quantitative methods. A thematic approach to qualitative data analysis with a coding framework guided by Consolidated Framework for Implementation Research (intervention characteristics, inner setting, outer setting, characteristics of individuals involved in implementation and the implementation process) was employed to analyse focus group discussion data. Statistical analysis was employed to analyze quantitative data collected through surveys.Results: Study participants included ECD stakeholders (ECD managers, social workers and dieticians) aged 34-52. Participants identified Ditokomane, Oranges, Mabele soft porridge, Dithotse and Dinawa as components of an IF that are suitable and acceptable for children under five years in ECD centres. Conclusion: ECD stakeholders co-created an IF diet to be implemented in ECD centres for children under five. Stakeholders are of the view that IF diet will have more health benefits on children than the current menu that is being used.
Restricted active space configuration interaction methods for strong correlation: Recent developments

Edited by: Anna Krylov, Associate Editor Abstract In this review we outline the theory and recent progress of the restricted active space configuration interaction (RASCI) methodology within the hole and particle approximation. The RASCI is a single reference approach based on the splitting of the orbital space in different subsets, in which the target CI space is expressed by the concomitant number of electrons and empty orbitals in each subspace. Initially, the method was born as a spin complete version of the spin-flip ansatz able to deal with any number of unpaired electrons. Since then, the method has experienced several improvements related to its theoretical foundations, its efficient implementation, in the characterization of RASCI wave functions, and in the calculation of molecular properties. It has shown to be especially suitable for the characterization of medium to large molecular diradicals and polyradicals, and to the study of photophysical processes involving open-shell species and/or multiexcitonic states, like in the singlet fission reaction. But, despite this success, several limitations emerge from the sever truncation of the excitation operator, which might translate into inaccurate relative energies between different regions of the potential energy surface, and overestimated (or underestimated) excitation energies. These errors are associated with the lack of dynamic correlation, which has motivated the development and implementation of various improvements based on multi-reference perturbation theory and to blend the RASCI wave function with density functional theory through range separation of electron–electron interactions. Finally, we discuss some of the properties available from RASCI wave functions and give potential future developments.
Electrospun Nanofiber Poly (3,4-ethylenedioxytriophene): poly (styrene sulfonate) / poly (vinyl alcohol) as Strain Sensor Application

A strain sensor based on poly (3,4-ethylenedioxytriophene): poly (styrene sulfonate)/poly (vinyl alcohol) (PEDOT: PSS/PVA) nanofiber has been successfully fabricated by electrospinning technique. Patterned copper wires were deposited on the mica flexible substrate with the distance of 1 mm. The sensor then characterized with various strain by one side bending. The conductivity of as-spun nanofiber mats can be adjusted from 0.03 to 1.2 µS cm-1 with various concentration of PVA and depends on its structure and its nanofiber diameter. The sensing mechanism of nanofiber-based strain sensor is due to the common piezoelectric effect of PEDOT:PSS polymer and unique nanostructure of nanofiber mats. When the sensor stretched, the length of nanofiber increase affecting the geometrical change and lead the increasing in resistance. This sensor shows good repeatability with gauge factor of 17. The performance of PEDOT:PSS/PVA nanofiber based strain sensor make nanofiber mats as promising alternative materials for strain sensor application.
Analysis of Natural Hydraulic Fracture Risk of Mudstone Cap Rocks in XD Block of Central Depression in Yinggehai Basin, South China Sea

The Yinggehai Basin is an important Cenozoic gas bearing basin in the South China Sea. With the gradual improvement of gas exploration and over-development in shallow layers, deep overpressured layers have become the main target for natural gas exploration. There are no large-scale faults in the strata above the Meishan Formation in the central depression, and hydraulic fracturing caused by overpressure in mudstone cap rocks is the key factor for the vertical differential distribution of gas. In this paper, based on the leak-off data, pore fluid pressure, and rock mechanics parameters, the Fault Analysis Seal Technology (FAST) method is used to analyze the hydraulic fracture risk of the main mudstones in the central depression. The results show that the blocks in the diapir zone have been subjected to hydraulic fracturing in the Huangliu cap rocks during the whole geological history, and the blocks in the slope zone which is a little distant from the diapirs has a lower overall risk of hydraulic fracture than the diapir zone. In geological history, the cap rocks in slope zone remained closed for a longer time than in diapir zone and being characterized by the hydraulic fracture risk decreases with the distance from the diapirs. These evaluation results are consistent with enrichment of natural gas, which accumulated in both the Yinggehai Formation and Huangliu Formation of the diapir zone, but it only accumulated in the the Huangliu Formations of the slope zone. The most reasonable explanation for the difference of the gas reservoir distribution is that the diapirs promote the development of hydraulic fractures: (1) diapirism transfers deep overpressure to shallow layers; (2) the small fault and fractures induced by diapir activities weakened the cap rock and reduced the critical condition for the natural hydraulic fractures. These effects make the diapir zone more prone to hydraulic fracturing, which are the fundamental reasons for the difference in gas enrichment between the diapir zone and the slope zone.
Impact of COVID-19 on resource families: Unique challenges and strengths

The emergence of COVID-19 forced significant adaptations for families worldwide. Children and youth in foster care and their caregivers or resource parents experience unique stressors. The current study aimed to understand the impact of the COVID-19 pandemic and “Safer-at-Home” orders on resource parents in Los Angeles County. Resource parents (n = 648) were surveyed about COVID-19 concerns, positive impact and strengths, access to and helpfulness of provided resources, visits with birth parents, children joining their families during the pandemic, and transition to telehealth. Between one-third and half of resource parents with foster or foster-adoptive children in their home reported significant anxiety about issues such as getting infected, uncertainty about the future, and financial hardship. In contrast, most resource parents reported some perceived benefits, such as increased family closeness. The most helpful resource reported was video visitation by social workers. A quarter of resource parents experienced in-person birth parent visits. Developmentally, parents with a foster or fosteradoptive child 0–5 years old reported significantly more worries related to COVID-19, while those with children of multiple ages reported feeling less valued as a resource parent and expressed more concerns about children falling behind with school, mental health and developmental services, birth parent visits, and delayed reunification. Lastly, younger parental age, fewer foster children in the home, and the less negative impact from COVID-19 a resource parent reported having were associated with an increased likelihood of resource parents welcoming a child into their home. Implications for policy and recommendations for practice are discussed.
MOOC DESIGN PRINCIPLES: TOPIC MODELLING-PYLDAVIS VISUALIZATION & SUMMARIZATION OF LEARNERS’ ENGAGEMENT

This research is based on the thought process that informed the design of a virtual reality massive open online course (MOOC) in FutureLearn. One of the main significant aspects of developing an online course for a large cohort of learners is to first consider the structure and pedagogic instructions and theories underpinning the design. This research covers aspects of good pedagogical design practice and perspectives used for structuring the content of the course. Designing an online course such as a MOOC requires careful consideration of the structure of delivery and the pedagogic flow of the instructional resources and process. The proposed virtual reality course follows good practice pedagogy from a design science perspective. The course content is structured in a logical manner that guides the learners in directing their studies in a sequential order of engagement that was designed by the course coordinator. This research reveals how good instructional pedagogy theories and principles help to facilitate teaching and learning easily. The development of concepts that lead to self-directed learning makes facilitating online learning very easy for the educators. The learners and course evaluations were done using incremental weekly quizzes and exercises. This course is developed for learners with little or no programming skills or no experience in virtual worlds (Augmented, Virtual and Mixed realities). The concepts were delivered with instructional structure to guide and direct the learners for independent learning no matter their location. In this course, learners’ engagement with the resources is taken into consideration and reflective observations are done based on the demography of the registered participants. Action research and qualitative content analysis methods were applied to evaluate the text data from the research. The main purpose of the research is to investigate learners’ reasons for engaging with the course structural resources provided and to explore aspects of mitigation for future MOOC designs. The result reveals that majority of the learners registered for the course to learn more about the virtual reality (VR) course and to learn from their interaction with other learners. This research applied some natural language processing (NLP) techniques to extract and summarize the prevalence topics or reasons for engagement from the icebreaker discussion. NLP techniques such as summarization, topic modelling and latent dirichlet allocation (LDA) were used to create the topic models for visualization.
Quorum sensing related activity of Aggregatibacter actinomycetemcomitans in periodontal disease: A review

Aggregatibacter actinomycetemcomitans is a significant pathogen in periodontal disease, contributing to aggressive and chronic inflammatory conditions of the periodontal area. This pathogen is shown to contribute to the tenacious biofilm formation in the oral cavity and results in persistent induction of pro-inflammatory response leads to progressive periodontitis. Besides the immune-modulatory capabilities, quorum sensing (QS) activity is believed to influence the virulence activities, leading to a progressive inflammatory response by the host. QS modulates the expression of genes involved in the processes related to survival and biofilm formation activities by answering the localized bacterial population's fluctuation. Understanding the QS activity of this pathogen and its impact on disease might be useful as an alternative approach to counteract the infection. Therefore, this review paper is focusing on the evaluation of the QS activities of A. actinomycetemcomitans and how this activity influences the progression of periodontal disease. Based on the previous findings, we found that there are possibilities the QS activity interrupted by enzymes or molecules that blocking the QS signals produced by other species of bacteria. However, due to minimal QS studies that have been done specifically on A. actinomycetemcomitans, the mechanism is not conclusive. Therefore, this might initiate an essential option for alternative treatment against periodontal pathogen infection and oral health care.