bluuebunny/crossref_metadata_2025 huggingface dataset:
Biobased Solvents for Pressurized Liquid Extraction of Nannochloropsis gaditana Omega-3 Lipids
Authors: Blanco-Llamero Cristina , Señoráns F. Javier
Published: February 2021

To develop greener extraction alternatives for microalgae biomass, ultrasound assisted extraction (UAE) and pressurized liquid extraction (PLE) with different biobased solvents were investigated, demonstrating that both techniques are useful alternatives for algal lipid extraction. Specifically, Nannochloropsis gaditana lipids were extracted by UAE and PLE at different temperatures and extraction times with sustainable solvents like 2-Methyltetrahydrofuran (2-MeTHF) and its mixtures with ethanol and other alcohols. The best oil yields for both PLE and UAE of N. gaditana were achieved with the mixture of 2-MeTHF:ethanol (1:3), reaching yields of up to 16.3%, for UAE at 50 °C and up to 46.1% for PLE at 120 °C. Lipid composition of the extracts was analyzed by HPLC-ELSD and by GC-MS to determine lipid species and fatty acid profile, respectively. Different fractionation of lipid species was achieved with PLE and solvent mixtures of different polarity. Thus, for the extraction of glycolipids, ethanolic extracts contained higher amounts of glycolipids and EPA, probably due to the higher polarity of the solvent. The optimized method was applied to microalgae Isochrysis galbana and Tetraselmis chuii showing the potential of mixtures of biobased solvents like 2-methyl-THF and ethanol in different proportions to efficiently extract and fractionate lipids from microalgal biomass.
Large-Scale Staphylococcus aureus Foodborne Disease Poisoning Outbreak among Primary School Children
Authors: Le Hao Hong Thi , Dalsgaard Anders , Andersen Paal Skytt , Nguyen Huong Minh , Ta Yen Thi , Nguyen Trung Thanh
Published: February 2021

A large-scale food poisoning outbreak happened at a school canteen in Ninh Binh Province, Vietnam, in 2018, resulting in the hospitalization of 352 students with clinical symptoms indicative of a staphylococcal food poisoning. A subsequent laboratory investigation detected Staphylococcus aureus in two food items—deep-fried shrimp and chicken floss—at up to 103 CFU/mL, and staphylococcal enterotoxins (SEs) in chicken floss at ≥0.211 ng SEs/g. S. aureus was also isolated from patients’ vomit and stool samples, and kitchen workers’ stool samples, as well as in frozen chicken meat, but not on the kitchen workers’ hand surfaces, suggesting the cause of this food poisoning outbreak was S. aureus contamination of the chicken meat. Molecular characterization revealed the S. aureus strains isolated from all samples were closely related; all belonged to sequence type (ST) ST6 and spa type t701 and carried both sea and sec genes. This SE-producing strain was resistant to penicillin and tetracycline, while still susceptible to oxacillin, erythromycin, gentamicin, methicillin, and vancomycin. Since S. aureus food poisonings are often underreported, our investigation added to the sparse qualitative and quantitative data of pathogenic S. aureus monitoring and surveillance in Vietnam, providing needed knowledge to guide preventative measures for future outbreaks.
Food Safety Concerns in “COVID-19 Era”
Authors: Ceniti Carlotta , Tilocca Bruno , Britti Domenico , Santoro Adriano , Costanzo Nicola
Published: February 2021

In March 2020, the World Health Organization (WHO) declared that the COVID-19 outbreak can be characterized as a pandemic. Human-to-human transmission of the SARS-CoV-2 virus may initially be blamed as the first cause of spread, but can an infection be contracted by ingestion of contaminated food or touching contaminated food surfaces? Recently cold-chain food contamination has been indicated as a possible source of many human cases in China. However, the risk of a food-related COVID-19 infection is still debated since the virus may reach people through a fresh product or packaging, which have been touched/sneezed on by infected people. This review summarizes the most recent evidence on the zoonotic origin of the pandemic, reports the main results regarding the transmission of SARS-CoV-2 through food or a food chain, as well as the persistence of the virus at different environmental conditions and surfaces. Emphasis is also posed on how to manage the risk of food-related COVID-19 spread and potential approaches that can reduce the risk of SARS-CoV-2 contamination.
Mixed-Mating Model of Reproduction Revealed in European Phytophthora cactorum by ddRADseq and Effector Gene Sequence Data
Authors: Pánek Matěj , Střížková Ivana , Zouhar Miloslav , Kudláček Tomáš , Tomšovský Michal
Published: February 2021

A population study of Phytophthora cactorum was performed using ddRADseq sequence variation analysis completed by the analysis of effector genes—RXLR6, RXLR7 and SCR113. The population structure was described by F-statistics, heterozygosity, nucleotide diversity, number of private alleles, number of polymorphic sites, kinship coefficient and structure analysis. The population of P. cactorum in Europe seems to be structured into host-associated groups. The isolates from woody hosts are structured into four groups described previously, while isolates from strawberry form another group. The groups are diverse in effector gene composition and the frequency of outbreeding. When populations from strawberry were analysed, both asexual reproduction and occasional outbreeding confirmed by gene flow among distinct populations were detected. Therefore, distinct P. cactorum populations differ in the level of heterozygosity. The data support the theory of the mixed-mating model for P. cactorum, comprising frequent asexual behaviour and inbreeding alternating with occasional outbreeding. Because P. cactorum is not indigenous to Europe, such variability is probably caused by multiple introductions of different lineages from the area of its original distribution, and the different histories of sexual recombination and host adaptation of particular populations.
Biogeographical Distribution and Community Assembly of Active Protistan Assemblages along an Estuary to a Basin Transect of the Northern South China Sea
Authors: Li Ran , Hu Chen , Wang Jianning , Sun Jun , Wang Ying , Jiao Nianzhi , Xu Dapeng
Published: February 2021

Marine protists are essential for globally critical biological processes, including the biogeochemical cycles of matter and energy. However, compared with their prokaryotic counterpart, it remains largely unclear how environmental factors determine the diversity and distribution of the active protistan communities on the regional scale. In the present study, the biodiversity, community composition, and potential drivers of the total, abundant, and rare protistan groups were studied using high throughput sequencing on the V9 hyper-variable regions of the small subunit ribosomal RNA (SSU rRNA) along an estuary to basin transect in the northern South China Sea. Overall, Bacillariophyta and Cercozoa were abundant in the surface water; heterotrophic protists including Spirotrichea and marine stramenopiles 3 (MAST-3) were more abundant in the subsurface waters near the heavily urbanized Pearl River estuary; Chlorophyta and Pelagophyceae were abundant at the deep chlorophyll maximum depth, while Hacrobia, Radiolaria, and Excavata were the abundant groups in the deep water. Salinity, followed by water depth, temperature, and other biological factors, were the primary factors controlling the distinct vertical and horizontal distribution of the total and abundant protists. Rare taxa were driven by water depth, followed by temperature, salinity, and the concentrations of PO43−. The active protistan communities were mainly driven by dispersal limitation, followed by drift and other ecological processes.
Time-Resolved Transcriptional Profiling of Epithelial Cells Infected by Intracellular Acinetobacter baumannii
Authors: Crua Asensio Nuria , Macho Rendón Javier , Torrent Burgas Marc
Published: February 2021

The rise in the number of antibiotic-resistant bacteria has become a serious threat to health, making it important to identify, characterize and optimize new molecules to help us to overcome the infections they cause. It is well known that Acinetobacter baumannii has a significant capacity to evade the actions of antibacterial drugs, leading to its emergence as one of the bacteria responsible for hospital and community-acquired infections. Nonetheless, how this pathogen infects and survives inside the host cell is unclear. In this study, we analyze the time-resolved transcriptional profile changes observed in human epithelial HeLa cells after infection by A. baumannii, demonstrating how it survives in host cells and starts to replicate 4 h post infection. These findings were achieved by sequencing RNA to obtain a set of Differentially Expressed Genes (DEGs) to understand how bacteria alter the host cells’ environment for their own benefit. We also determine common features observed in this set of genes and identify the protein–protein networks that reveal highly-interacted proteins. The combination of these findings paves the way for the discovery of new antimicrobial candidates for the treatment of multidrug-resistant bacteria.
Inhibition of Dermatophyte Fungi by Australian Jarrah Honey
Authors: Guttentag Annabel , Krishnakumar Krishothman , Cokcetin Nural , Hainsworth Steven , Harry Elizabeth , Carter Dee
Published: February 2021

Superficial dermatophyte infections, commonly known as tineas, are the most prevalent fungal ailment and are increasing in incidence, leading to an interest in alternative treatments. Many floral honeys possess antimicrobial activity due to high sugar, low pH, and the production of hydrogen peroxide (H2O2) from the activity of the bee-derived enzyme glucose oxidase. Australian jarrah (Eucalyptus marginata) honey produces particularly high levels of H2O2 and has been found to be potently antifungal. This study characterized the activity of jarrah honey on fungal dermatophyte species. Jarrah honey inhibited dermatophytes with minimum inhibitory concentrations (MICs) of 1.5–3.5% (w/v), which increased to ≥25% (w/v) when catalase was added. Microscopic analysis found jarrah honey inhibited the germination of Trichophyton rubrum conidia and scanning electron microscopy of mature T. rubrum hyphae after honey treatment revealed bulging and collapsed regions. When treated hyphae were stained using REDOX fluorophores these did not detect any internal oxidative stress, suggesting jarrah honey acts largely on the hyphal surface. Although H2O2 appears critical for the antifungal activity of jarrah honey and its action on fungal cells, these effects persisted when H2O2 was eliminated and could not be replicated using synthetic honey spiked with H2O2, indicating jarrah honey contains agents that augment antifungal activity.
A New Computer Model for Evaluating the Selective Binding Affinity of Phenylalkylamines to T-Type Ca2+ Channels
Authors: Lu You , Li Ming
Published: February 2021

To establish a computer model for evaluating the binding affinity of phenylalkylamines (PAAs) to T-type Ca2+ channels (TCCs), we created new homology models for both TCCs and a L-type calcium channel (LCC). We found that PAAs have a high affinity for domains I and IV of TCCs and a low affinity for domains III and IV of the LCC. Therefore, they should be considered as favorable candidates for TCC blockers. The new homology models were validated with some commonly recognized TCC blockers that are well characterized. Additionally, examples of the TCC blockers created were also evaluated using these models.
The Contribution of Pharmacists and Pharmacy Technicians to Person-Centred Care within a Medicine’s Optimisation in Care Homes Service: A Qualitative Evaluation
Authors: Fowler Davis Sally , Cholerton Rachel , Freeman-Parry Louise , Tsoneva Jo
Published: February 2021

Pharmacists and pharmacy technicians seek to improve person-centred care. Improvements to systems for care homes seeks to reduce medicines waste and inefficiency, particularly through supporting care home staff, to enhance safer administration of medicines. A complex evaluation used qualitative design and utilised narrative enquiry, and team members and key stakeholders were interviewed. Framework analysis was used, aligning findings to a person-centred care framework for older people. The Medicines Optimisation in Care Homes (MOCH) team brokered improvement practices across care homes to enhance person-centred care. The framework analysis confirms that the team used ‘authentic attention’ in relation to the residents’ experiences and flexibility in relation to negotiating medication. The importance of transparency of processes and systems in medicines management is highlighted, alongside requirements for person-centred care to make explicit the reason for taking a medication, and the continuous discussion with a range of stakeholders about the continuing need for particular medications. The outcome of the evaluation includes insights into a new area of pharmacy practice in community, based on the skills, knowledge, and experience of pharmacists and pharmacy technicians working in the care home sector. Further study is needed into the efficacy and outcomes of medicines management interventions.
Influence of Cerium Oxide Nanoparticles on Two Terrestrial Wild Plant Species
Authors: Lizzi Daniel , Mattiello Alessandro , Adamiano Alessio , Fellet Guido , Gava Emanuele , Marchiol Luca
Published: February 2021

Most current studies on the relationships between plans and engineered nanomaterials (ENMs) are focused on food crops, while the effects on spontaneous plants have been neglected so far. However, from an ecological perspective, the ENMs impacts on the wild plants could have dire consequences on food webs and ecosystem services. Therefore, they should not be considered less critical. A pot trial was carried out in greenhouse conditions to evaluate the growth of Holcus lanatus L. (monocot) and Diplotaxis tenuifolia L. DC. (dicot) exposed to cerium oxide nanoparticles (nCeO2). Plants were grown for their entire cycle in a substrate amended with 200 mg kg−1nCeO2 having the size of 25 nm and 50 nm, respectively. nCeO2 were taken up by plant roots and then translocated towards leaf tissues of both species. However, the mean size of nCeO2 found in the roots of the species was different. In D. tenuifolia, there was evidence of more significant particle aggregation compared to H. lanatus. Further, biomass variables (dry weight of plant fractions and leaf area) showed that plant species responded differently to the treatments. In the experimental conditions, there were recorded stimulating effects on plant growth. However, nutritional imbalances for macro and micronutrients were observed, as well.
Resveratrol Inhibits Venezuelan Equine Encephalitis Virus Infection by Interfering with the AKT/GSK Pathway
Authors: Lehman Caitlin W. , Kehn-Hall Kylene , Aggarwal Megha , Bracci Nicole R. , Pan Han-Chi , Panny Lauren , Lamb Robert A. , Lin Shih-Chao
Published: February 2021

The host proteins Protein Kinase B (AKT) and glycogen synthase kinase-3 (GSK-3) are associated with multiple neurodegenerative disorders. They are also important for the replication of Venezuelan equine encephalitis virus (VEEV), thereby making the AKT/GSK-3 pathway an attractive target for developing anti-VEEV therapeutics. Resveratrol, a natural phytochemical, has been shown to substantially inhibit the AKT pathway. Therefore, we attempted to explore whether it exerts any antiviral activity against VEEV. In this study, we utilized green fluorescent protein (GFP)- and luciferase-encoding recombinant VEEV to determine the cytotoxicity and antiviral efficacy via luciferase reporter assays, flow cytometry, and immunofluorescent assays. Our results indicate that resveratrol treatment is capable of inhibiting VEEV replication, resulting in increased viability of Vero and U87MG cells as well as reduced virion production and viral RNA contents within host cells for at least 48 h with a single treatment. Furthermore, the suppression of apoptotic signaling adaptors, caspase-3, caspase-7, and annexin V may also be implicated in resveratrol-mediated antiviral activity. We found that decreased phosphorylation of the AKT/GSK-3 pathway, mediated by resveratrol, can be triggered during the early stages of VEEV infection, suggesting that resveratrol disrupts the viral replication cycle and consequently promotes cell survival. Finally, molecular docking and dynamics simulation studies revealed that resveratrol can directly bind to VEEV glycoproteins, which may interfere with virus attachment and entry. In conclusion, our results suggest that resveratrol exerts inhibitory activity against VEEV infection and upon further modification could be a useful compound to study in neuroprotective research and veterinary sciences.
Antiinflammatory Medicinal Plants from the Ugandan Greater Mpigi Region Act as Potent Inhibitors in the COX-2/PGH2 Pathway
Authors: Schultz Fabien , Osuji Ogechi Favour , Wack Barbara , Anywar Godwin , Garbe Leif-Alexander
Published: February 2021

Our study investigates 16 medicinal plants via assessment of inhibition of proinflammatory enzymes such as cyclooxygenases (COX). The plants are used by traditional healers in the Greater Mpigi region in Uganda to treat inflammation and related disorders. We present results of diverse in vitro experiments performed with 76 different plant extracts, namely, (1) selective COX-2 and COX-1 inhibitor screening; (2) 15-LOX inhibition screening; (3) antibacterial resazurin assay against multidrug-resistant Staphylococcus aureus, Listeria innocua, Listeria monocytogenes, and Escherichia coli K12; (4) DPPH assay for antioxidant activity; and (5) determination of the total phenolic content (TPC). Results showed a high correlation between traditional use and pharmacological activity, e.g., extracts of 15 out of the 16 plant species displayed significant selective COX-2 inhibition activity in the PGH2 pathway. The most active COX-2 inhibitors (IC50 < 20 µg/mL) were nine extracts from Leucas calostachys, Solanum aculeastrum, Sesamum calycinum subsp. angustifolium, Plectranthus hadiensis, Morella kandtiana, Zanthoxylum chalybeum, and Warburgia ugandensis. There was no counteractivity between COX-2 and 15-LOX inhibition in these nine extracts. The ethyl acetate extract of Leucas calostachys showed the lowest IC50 value with 0.66 µg/mL (COX-2), as well as the most promising selectivity ratio with 0.1 (COX-2/COX-1). The TPCs and the EC50 values for DPPH radical scavenging activity showed no correlation with COX-2 inhibitory activity. This led to the assumption that the mechanisms of action are most likely not based on scavenging of reactive oxygen species and antioxidant activities. The diethyl ether extract of Harungana madagascariensis stem bark displayed the highest growth inhibition activity against S. aureus (MIC value: 13 µg/mL), L. innocua (MIC value: 40 µg/mL), and L. monocytogenes (MIC value: 150 µg/mL). This study provides further evidence for the therapeutic use of the previously identified plants used medicinally in the Greater Mpigi region.
Temperature-Dependent Viscosity Model for Silicone Oil and Its Application in Viscous Dampers
Authors: Venczel Márk , Bognár Gabriella , Veress Árpád
Published: February 2021

Silicone fluids belong to the group of pseudoplastic non-Newtonian fluids with complex rheological characteristics. They are considered in basic and applied researches and in a wide range of industrial applications due to their favorable physical and thermal properties. One of their specific field of applications in the automotive industry is the working fluid of viscous torsional vibration dampers. For numerical studies in the design and development phase of this damping product, it is essential to have thorough rheological knowledge and mathematical description about the silicone oil viscosity. In the present work, adopted rheological measurement results conducted on polydimethylsiloxane manufactured by Wacker Chemie with initial viscosity of 1000 Pas (AK 1 000 000 STAB silicone oil) are processed. As a result of the parameter identification by nonlinear regression, the temperature-dependent parameter curves of the Carreau–Yasuda non-Newtonian viscosity model are generated. By implementing these parameter sets into a Computational Fluid Dynamics (CFD) software, a temperature- and shear-rate-dependent viscosity model of silicone fluid was tested, using transient flow and thermal simulations on elementary tube geometries in the size range of a real viscous torsional vibration damper’s flow channels and filling chambers. The numerical results of the finite volume method provide information about the developed flow processes, with especial care for the resulted flow pattern, shear rate, viscosity and timing.
The Technological Advances in Embryo Selection and Genetic Testing: A Look Back at the Evolution of Aneuploidy Screening and the Prospects of Non-Invasive PGT
Authors: Burks Channing , Van Heertum Kristin , Weinerman Rachel
Published: February 2021

Since the birth of the first IVF baby, Louise Brown, in 1978, researchers and clinicians have sought ways to improve pregnancy outcomes through embryo selection. In the 1990s, blastomere biopsy and fluorescence in situ hybridization (FISH) were developed in human embryos for the assessment of aneuploidy and translocations. Limitations in the number of chromosomes that could be assayed with FISH lead to the development of comparative genomic hybridization (CGH); however, pregnancy rates overall were not improved. The later development of trophectoderm biopsy with comprehensive chromosome screening (CCS) technologies, as well as the subsequent development of next-generation sequencing (NGS), have shown much greater promise in improving pregnancy and live birth rates. Recently, many studies are focusing on the utilization of non-invasive preimplantation genetic testing (niPGT) in an effort to assess embryo ploidy without exposing embryos to additional interventions.
The Flash Floods Risk in the Local Spatial Planning (Case Study: Lublin Upland, E Poland)
Authors: Baran-Zgłobicka Bogusława , Godziszewska Dominika , Zgłobicki Wojciech
Published: February 2021

Flash floods pose a significant threat to humans but the state of our knowledge on the occurrence and related risk of such phenomena is insufficient. At the same time, many climate change models predict that extreme rainfall events will occur more and more frequently. Identifying areas susceptible to flash floods is more complicated that in the case of floods occurring in the valley bottoms of large rivers. Flood risk maps in Poland have not been developed for small catchments. The study objective was to assess whether the threat related to flash floods is taken into account in the spatial planning system of municipalities. Studies were conducted in the Lublin Upland, E Poland (an area of about 7200 km2). A preliminary assessment of susceptibility of 369 catchments to flash floods was carried out in a GIS environment using multi criteria analysis. The susceptible catchments cover about 30% of the area. Existing planning documents, flood hazard and flood risk maps were analyzed for municipalities located in the catchments with highest susceptibility to this phenomenon. Our results show that flash flood risk is usually not recognized at the level of local governments even when it is significant. Local planning documents do not take into account the existence of this threat.
Performance of Optical Structural Vibration Monitoring Systems in Experimental Modal Analysis
Authors: Kalybek Maksat , Bocian Mateusz , Nikitas Nikolaos
Published: February 2021

Image-based optical vibration measurement is an attractive alternative to the conventional measurement of structural dynamics predominantly relying on accelerometry. Although various optical vibration monitoring systems are now readily available, their performance is currently not well defined, especially in the context of experimental modal analysis. To this end, this study provides some of the first evidence of the capability of optical vibration monitoring systems in modal identification using input–output measurements. A comparative study is conducted on a scaled model of a 3D building frame set in a laboratory environment. The dynamic response of the model to an impulse excitation from an instrumented hammer, and an initial displacement, is measured by means of five optical motion capture systems. These include commercial and open-source systems based on laser Doppler velocimetry, fiducial markers and marker-less pattern recognition. The performance of these systems is analysed against the data obtained with a set of high-precision accelerometers. It is shown that the modal parameters identified from each system are not always equivalent, and that each system has limitations inherent to its design. Informed by these findings, a guidance for the deployment of the considered optical motion capture systems is given, aiding in their choice and implementation for structural vibration monitoring.
Robust Filtering Techniques for RTK Positioning in Harsh Propagation Environments
Authors: Medina Daniel , Li Haoqing , Vilà-Valls Jordi , Closas Pau
Published: February 2021

Global navigation satellite systems (GNSSs) play a key role in intelligent transportation systems such as autonomous driving or unmanned systems navigation. In such applications, it is fundamental to ensure a reliable precise positioning solution able to operate in harsh propagation conditions such as urban environments and under multipath and other disturbances. Exploiting carrier phase observations allows for precise positioning solutions at the complexity cost of resolving integer phase ambiguities, a procedure that is particularly affected by non-nominal conditions. This limits the applicability of conventional filtering techniques in challenging scenarios, and new robust solutions must be accounted for. This contribution deals with real-time kinematic (RTK) positioning and the design of robust filtering solutions for the associated mixed integer- and real-valued estimation problem. Families of Kalman filter (KF) approaches based on robust statistics and variational inference are explored, such as the generalized M-based KF or the variational-based KF, aiming to mitigate the impact of outliers or non-nominal measurement behaviors. The performance assessment under harsh propagation conditions is realized using a simulated scenario and real data from a measurement campaign. The proposed robust filtering solutions are shown to offer excellent resilience against outlying observations, with the variational-based KF showcasing the overall best performance in terms of Gaussian efficiency and robustness.
New Position Candidate Identification via Clustering toward an Extensible On-Body Smartphone Localization System
Authors: Saito Mitsuaki , Fujinami Kaori
Published: February 2021

On-body device position awareness plays an important role in providing smartphone-based services with high levels of usability and quality. Traditionally, the problem assumed that the positions that were supported by the system were fixed at the time of design. Thus, if a user stores his/her terminal into an unsupported position, the system forcibly classifies it into one of the supported positions. In contrast, we propose a framework to discover new positions that are not initially supported by the system, which adds them as recognition targets via labeling by a user and re-training on-the-fly. In this article, we focus on a component of identifying a set of samples that are derived from a single storing position, which we call new position candidate identification. Clustering is applied as a key component to prepare a reliable dataset for re-training and to reduce the user’s burden of labeling. Specifically, density-based spatial clustering of applications with noise (DBSCAN) is employed because it does not require the number of clusters in advance. We propose a method of finding an optimal value of a main parameter, Eps-neighborhood (eps), which affects the accuracy of the resultant clusters. Simulation-based experiments show that the proposed method performs as if the number of new positions were known in advance. Furthermore, we clarify the timing of performing the new position candidate identification process, in which we propose criteria for qualifying a cluster as the one comprising a new position.
Explaining Neural Networks Using Attentive Knowledge Distillation
Authors: Lee Hyeonseok , Kim Sungchan
Published: February 2021

Explaining the prediction of deep neural networks makes the networks more understandable and trusted, leading to their use in various mission critical tasks. Recent progress in the learning capability of networks has primarily been due to the enormous number of model parameters, so that it is usually hard to interpret their operations, as opposed to classical white-box models. For this purpose, generating saliency maps is a popular approach to identify the important input features used for the model prediction. Existing explanation methods typically only use the output of the last convolution layer of the model to generate a saliency map, lacking the information included in intermediate layers. Thus, the corresponding explanations are coarse and result in limited accuracy. Although the accuracy can be improved by iteratively developing a saliency map, this is too time-consuming and is thus impractical. To address these problems, we proposed a novel approach to explain the model prediction by developing an attentive surrogate network using the knowledge distillation. The surrogate network aims to generate a fine-grained saliency map corresponding to the model prediction using meaningful regional information presented over all network layers. Experiments demonstrated that the saliency maps are the result of spatially attentive features learned from the distillation. Thus, they are useful for fine-grained classification tasks. Moreover, the proposed method runs at the rate of 24.3 frames per second, which is much faster than the existing methods by orders of magnitude.
Multi-Dimensional Uniform Initialization Gaussian Mixture Model for Spar Crack Quantification under Uncertainty
Authors: Xu Qiuhui , Yuan Shenfang , Huang Tianxiang
Published: February 2021

Guided Wave (GW)-based crack monitoring method as a promising method has been widely studied, as this method is sensitive to small cracks and can cover a wide monitoring range. Online crack quantification is difficult as the initiation and growth of crack are affected by various uncertainties. In addition, crack-sensitive GW features are influenced by time-varying conditions which further increase the difficulty in crack quantification. Considering these uncertainties, the Gaussian mixture model (GMM) is studied to model the probability distribution of GW features. To further improve the accuracy and stability of crack quantification under uncertainties, this paper proposes a multi-dimensional uniform initialization GMM. First, the multi-channel GW features are integrated to increase the accuracy of crack quantification, as GW features from different channels have different sensitivity to cracks. Then, the uniform initialization method is adopted to provide more stable initial parameters in the expectation-maximization algorithm. In addition, the relationship between the probability migration index of GMMs and crack length is calibrated with fatigue tests on prior specimens. Finally, the proposed method is applied for online crack quantification on the notched specimen of an aircraft spar with complex fan-shaped cracks under uncertainty.
Synchronized Hardware-Registered VIS-NIR Imaging Spectroscopy and 3D Sensing on a Fresco by Botticelli
Authors: Striova Jana , Pezzati Luca , Pampaloni Enrico , Fontana Raffaella
Published: February 2021

We discuss a synchronised sensing technique for the analysis of painted surfaces of frescos. Specifically, the performance of Visible-Near Infrared (VIS-NIR) Reflectance Imaging Spectroscopy (RIS) synchronized with three-dimensional (3D) acquisition is demonstrated in the study of a detached mural painting by Alessandro Botticelli. Synchronized sensing generates georeferenced data for simplified data treatment and interpretation. We show how such output data can provide key information to interpret important fresco surface and subsurface features (e.g., painting technique, material composition, pentimenti).
The Chemsex ‘Consent Ladder’ in Male Sex Work: Perspectives of Health Providers on Derailment and Empowerment
Authors: Brooks-Gordon Belinda , Ebbitt Euan
Published: February 2021

Sexualized substance use or ‘chemsex’ is a key element in the syndemic of violence and infection in gay, bisexual, and other men who have sex with men. Chemsex is more prolific amongst men who have sex with men but is also associated with high risk behaviours that can negatively impact on health and wellbeing in heterosexual, bisexual men and women, and in homosexual women too. This qualitative study investigated perceptions and experiences of chemsex, motivations, cisgender male sex work, consent, economic exploitation, and ways to address and reduce harms. We conducted semi-structured interviews with health care providers and their clients—including sex workers and their customers (n = 14) between the ages of 28 and 46 years following a purposive sampling strategy. Interview topics included perceptions and experiences of chemsex use, reasons for drug use and chemsex, and proposals to address harms associated with chemsex in the UK. Interviews were audio-recorded, transcribed, coded, and analysed using Grounded Theory. The findings revealed a stepwise process of chemsex use in a ‘ladder of consent’, whereby the process starts with willing participation that is both highly pleasurable and controllable. Sexual polydrug activity often descended in rungs so that lines of consent became blurred, and even broken, resulting in physical detriment and financial exploitation. Strategies for elevation back up the consent ladder also emerged. The findings clarify the conditions of willing participation, the stepwise relationship to exploitation, and the support strategies that help re-empower individuals whose lives get taken over by chemsex, including peer-to-peer support, poly-centres, and smartphone apps to climb back up the consent ladder to improve the health, safety, and social rights of sex workers.
Evolutionary Optimization of Case-Based Forecasting Algorithms in Chaotic Environments
Authors: Musaev Alexander , Borovinskaya Ekaterina
Published: February 2021

The problem of dynamic adaptation of prediction algorithms in chaotic environments based on identification of the situations-analogs in the database of retrospective observations is considered. Under conditions of symmetrical and unsymmetrical chaotic dynamics, traditional computational schemes of precedent prediction turn out to be ineffective. In this regard, a dynamic adaptation of precedent analysis algorithms based on the method of evolutionary modeling is proposed. Implementation of the computational precedent prediction scheme for chaotic processes as well as the evolutionary modeling method are described.
Morphometry-Driven Divergence in Decadal Changes of Sediment Property in Floodplain Water Bodies
Authors: Pongsivapai Pongpet , Negishi Junjiro N. , Izumi Hokuto , Garrido Paolo A. , Kuramochi Kanta
Published: February 2021

Sediments are potentially the internal source that supply nutrients to water in lentic to semi-lentic ecosystems. The understanding of factors that cause temporal changes in sediment properties is critical for the internal source management. This study investigated the spatial variations and temporal changes in sediment properties in relation to their controlling factors in water bodies of the Ishikari River, Northern Japan. Sediment data in 29 water bodies were measured twice (around 2005 and 2019) to study the temporal changes in sediment properties, and were compared using Generalized Linear Mixed Models (GLMMs). The controlling factors of sediment properties including catchment and morphometry were examined by partial least square (PLS) regression. Our results showed that the temporal change in sediment properties over decades was largely driven by morphometry, while land use in the catchment played a relatively minor role in those changes. The rate of change in organic matter (OM) differed among water bodies depending on their morphometry. The small and shallow water bodies provided suitable habitat for macrophytes that led to OM deposits, resulting to an increase in OM and OM to total nitrogen (TN) ratio over time. The consequences of these changes are important for internal source management and biodiversity conservation.
La experimentación científica en Educación Inicial
Authors: Castillo Fraismar
Published: February 2021

La presente investigación se planteó promover la experimentación científica en los niños de Educación Inicial, a partir del diseño de estrategias de enseñanza que fueran innovadoras. La metodología empleada fue bajo un enfoque cualitativo fundamentado en una investigación de campo de carácter descriptivo – interpretativo. Los sujetos fueron dos docentes y 31 niños del primer grupo del Preescolar Ambrosio Plaza, ubicado en Guarenas, estado Miranda, Venezuela. Los resultados evidenciaron que los docentes en esta institución imparten sus clases de manera tradicional, esto es por áreas de aprendizaje para que los niños ejecuten alguna actividad cotidiana. De allí que se diseñaran unas estrategias de enseñanza que mostraran una estructura metodológica de pedagogía activa para promover la exploración y experimentación del entorno natural de los niños del preescolar. Todo esto resultará altamente efectivo por cuanto se despertará el interés, la motivación y la curiosidad de los niños.
Educación popular, una cosmovisión desde la cotidianidad:Un estudio contextualizado en una comunidad campesina
Authors: Guédez Inojosa Jorge Moisés , Pérez Veloz José
Published: February 2021

El propósito fue comprender la educación popular desde la cosmovisión de la vida cotidiana de los actores sociales, en el contexto de la comunidad de Palmero, San Carlos, estado Cojedes. Se empleó el enfoque cualitativo, bajo el paradigma interpretativo, método etnográfico. La fiabilidad se obtuvo a través de la técnica de triangulación. Se utilizó para la recolección de datos la observación participativa, el diario de campo y entrevistas. Las conclusiones permitieron evidenciar un contraste vivencial del residente de la comunidad, pues actúa como si no le perteneciera el contexto del cual se beneficia de la actividad agrícola, fuente de sostenibilidad económica practicada como rutina, mediante la tala y quema, sin valorar la importancia hacia la condición humana causando gran impacto ambiental, donde el camino para solucionar el problema es la educación popular, cuyo proyecto implementado por la comunidad desde 1997, no ha tenido apoyo de los entes del Estado venezolano, aun así está dando sus frutos positivos de manera lenta y progresiva.
Una interacción entre la universidad con las comunidades a través de técnicas artesanales en procesamiento de alimentos
Authors: Martínez González Lizzi Arelis , Ferreira de Bravo María Adilia
Published: February 2021

El objetivo de esta investigación fue proponer un plan de capacitación sobre técnicas artesanales en procesamiento de alimentos como interacción de la Universidad Nacional Experimental Simón Rodríguez y la Comunidad de Palmero Municipio Ezequiel Zamora, estado Cojedes- Venezuela. Se fundamentó en la agroecología y la teoría del aprendizaje constructivista de Piaget, con un nivel descriptivo, modalidad Proyecto factible, tomando como población a los habitantes de la Comunidad de Palmero. La técnica empleada fue la encuesta con un cuestionario tipo Likert, el cual permitió diagnosticar la necesidad de un plan de capacitación sobre técnicas artesanales en procesamiento de alimentos, con una confiabilidad Coeficiente Alpha de Cronbach (0.85).Los resultados fueron favorables: la obtención de la interacción universidad con la comunidad, fomentando el consumo de alimentos agroecológicos, exaltando el cuido del medio ambiente, mejorando así la calidad de vida.
Instrumentos para develar indicadores de riesgo de la discalculia en estudiantes de Educación Primaria
Authors: Martínez Aguirre Carlos José
Published: February 2021

La presente investigación consiguió diseñar un instrumento para develar los indicadores de riesgo de la dificultad en el aprendizaje de la matemática (Discalculia) en los estudiantes de educación primaria. Dicho estudio quedó conformado por veinticuatro docentes de aula de la U.E. “Juan Antonio Michelena”, donde la muestra fue 30%, equivalente a siete docentes. Seguidamente, durante la recolección de los datos se aplicó una encuesta constituida por cincuenta ítems dicotómicos cuyas alternativas de respuestas fueron SI o NO, el mismo fue validado por cinco expertos. Luego, de aplicar dicho instrumento se obtuvo a través del coeficiente de Kuder-Richardson, un índice confiable de 0.8406 siendo considerado muy alto. De allí; se analizaron los datos arrojados por la encuesta y entre otras conclusiones se observó la necesidad de proveer al docente de la información necesaria acerca de los indicadores de riesgo de las Dificultades específicas en el Aprendizaje de la Matemática (Discalculia).
Competencias Tecnológicas de Información y Comunicación en los docentes en formación de Física a nivel universitario
Authors: Zamora Rengifo Ricardo Javier
Published: February 2021

La presente investigación tuvo como propósito describir las Competencias Tecnológicas de Información y Comunicación (TIC) de los docentes en formación de la mención de Física de la FACE –UC caso: estudiantes del Seminario Proyecto de Investigación y Trabajo Especial de Grado de la mención de Física en la facultad de Ciencias de la Educación de la Universidad de Carabobo. El estudio se enmarcó en una investigación del tipo descriptivo, bajo un diseño de campo no experimental y transeccional. La población estuvo constituida por diez (10) sujetos. Para la recolección de datos se utilizó un instrumento validado por juicio de expertos elaborado por Guarapano y Martínez (2012), se realizó el cálculo de la confiabilidad mediante el Alfa de Cronbach, el cual arrojó un coeficiente de 0,87 que indica ser altamente confiable, según Ruiz (2002). Del análisis de los resultados se evidenció que los docentes en formación afirman tener Competencias Tecnológicas positivas.
Aprender historia en la universidad: enseñanza mediante entornos virtuales. Una tarea pendiente de los docentes de Ciencias sociales
Authors: Quintero Galbán Luis Guillermo
Published: February 2021

La presente investigación tuvo como objetivo general analizar la aplicación de un entorno virtual para el aprendizaje de contenidos de Historia Universal, en la carrera Educación mención Ciencias Sociales de las universidades del estado Zulia. Se fundamentó en los aportes teóricos de Gorocica (2012), Mariño (2008), Godoy (2008), entre otros. El tipo de investigación empleado fue descriptiva y proyectiva, con un diseño no experimental y de campo. Los resultados arrojados permiten confirmar que los profesores deben afianzar sus estrategias didácticas a través del empleo de competencias tecnológicas, herramientas síncronas y asíncronas e incorporar las plataformas virtuales institucionales que ofrecen sus casas de estudios para promover en el estudiante el uso de aulas virtuales, con el que se promovería el aprendizaje de contenidos de una materia que presenta contenidos extensos, pero apoyados en las nuevas tecnologías contextualizadas favorecería la aprehensión de conocimientos de procesos históricos actuales vinculados a su quehacer cotidiano.
Procesos operativos para la admisión estudiantil en universidades públicas de la Costa Oriental del Lago
Authors: Rodríguez Eglys
Published: February 2021

La investigación tuvo como propósito describir el proceso operativo aplicado en los departamentos de admisión estudiantil de las universidades públicas de la Costa Oriental del Lago. El estudio fue descriptivo con diseño de campo, no experimental, transeccional. La población estuvo conformada por las universidades públicas de la Costa Oriental del Lago. La técnica de recolección fue la encuesta y el instrumento un cuestionario con escala de frecuencia, compuesto por 15 ítems, se utilizó el juicio de expertos para su validez y el coeficiente Alfa Cronbach para su confiabilidad, obteniéndose 0,96. El análisis de los datos se realizó mediante la estadística descriptiva, a través del estudio de la media aritmética. Se concluye que se aplican planes de acciones que permiten planificar y controlar los servicios ofrecidos para alcanzar los objetivos operativos, a través de la decisión del proceso, diseño del proceso, control del proceso, mejoras del proceso y selección del proceso.
Competencias investigativas en docentes de la asignatura de investigación de educación básica y media
Authors: Barón Pinto Lyda Lorena
Published: February 2021

El objetivo de la investigación fue describir las competencias investigativas que poseen los docentes de la asignatura de investigación de educación básica y media, de las instituciones educativas de Sogamoso – Boyacá. La investigación fue descriptiva, con un diseño de campo, transeccional, contemporáneo. La población estuvo conformada por 38 docentes de educación básica y media que orientan la asignatura de investigación en las instituciones educativas de Sogamoso, Boyacá. Para el análisis de datos se utilizaron frecuencias, porcentajes, y medianas. Los hallazgos evidencian que las competencias investigativas de los docentes y la formación metodológica recibida no son suficientes para desarrollar investigaciones de calidad. La sinergia competencias actitudinales fue la que mejor puntaje obtuvo, la sinergia competencias cognitivas fue la más baja y la sinergia competencias procedimentales fue regular, lo que quiere decir que los docentes, manifiestan una actitud positiva frente a la investigación.
Transformación curricular en el nivel de Educación Media y su incidencia en el desempeño docente
Authors: Rivero Silva Yuly Marisol
Published: February 2021

El presente estudio tuvo como objetivo dilucidar la transformación curricular del nivel de Educación Media y su incidencia en el desempeño docente del Área de Producción de Bienes y Servicios de la Unidad Educativa Nacional Fernando Peñalver (Municipio Valencia, Venezuela). Se fundamentó en la teoría del aprendizaje significativo de Ausubel (1983), pues este propone un modelo para una adecuada labor educativa y lograr el aprendizaje deseado. Se inscribió en un estudio de campo, tipo descriptivo. La muestra estuvo conformada por cinco docentes, a los cuales se les aplicó una encuesta de 15 preguntas, cuyas opciones de respuestas fueron dicotómicas. De acuerdo a los resultados obtenidos, se llegó a la conclusión de que es necesario una buena orientación a los docentes y en especial a los que facilitan el área de Educación para el Trabajo, la cual les permita conocer de manera didáctica y continua los cambios curriculares, para interactuar con las transformaciones propuestas por el Ministerio del Poder Popular para la Educación.
Webquest para el aprendizaje del contenido de derivadas por definición en la asignatura Cálculo a nivel universitario
Authors: Vitriago Casadiego Osmel , Badillo Mieres Victor David
Published: February 2021

La presente investigación tuvo como objetivo proponer una Webquest para el aprendizaje del contenido de derivadas por definición en la asignatura Cálculo I del tercer semestre de la mención matemática de la Facultad de Ciencias de la Educación-Universidad de Carabobo (FaCE-UC). Esta se sustentó bajo las teorías de Ausubel (1983), el cual habla acerca del aprendizaje significativo, además de Cabero (2007) al realizar una integración de la tecnología en el ámbito educativo. El diseño fue de campo, no experimental, tipo proyectivo. Se tomó en cuenta una población conformada por nueve (9) estudiantes, donde se les aplicó un cuestionario de selección simple de veintidós (22) preguntas, como técnica de instrumento de recolección de datos. El estudio es un aporte didáctico tecnológico, que busca mejorar el proceso de enseñanza y aprendizaje en los estudiantes de la asignatura Cálculo I de la mención de Matemática de la FaCE-UC, Venezuela.