Miracle-dz/UniFAR-FTUs huggingface dataset:
Assessing pupils' skills in experimentation

This study is concerned with different forms of assessment of pupils' skills in experimentation. The findings of three studies are reported. Study 1 investigates whether it is possible to develop reliable multiple-choice tests for the skills of forming hypotheses, designing experiments and analysing experimental data. Study 2 compares scores from multiple-choice tests with scores from an open-response test in order to investigate how to assess pupils' skills in planning two-factor experiments. Study 3 investigates whether scores from multiple-choice tests correlate with student performance in a practical test on seed germination.
Marine propeller acoustic modelling: comparing CFD results with an acoustic analogy method

Propeller noise and vibration is important in the design of ships in order to improve comfort, reduce signature or mitigate environmental impact. Since acoustic measurements are often difficult to perform in typical maritime experimental facilities, acoustic predictions based on computations are attractive. We utilised an acoustic analogy method to make acoustic predictions based on post-processing of a hydrodynamic simulation. Grids were designed to improve the resolution of the pressure field away from the propeller. This was then used as a comparison for the acoustic analogy method. The local pressure at a field point was shown to be more sensitive to grid refinement than integrated propeller performance coefficients. Although the predictions made using the acoustic analogy in general agree well with the directly computed pressure, the method also suffers from sensitivity to the required input data (pressure, velocity and acceleration). For a probe located further away from the propeller, where the pressure amplitudes are smaller, numerical disturbances are seen, which could affect predictions, especially when higher frequencies are of interest. This highlights the need for a well-converged accurate hydrodynamic solution when using an acoustic analogy method. Visualisation of the acoustic sources not only confirms the dominant noise-generating effects but also allows the spatial distribution of the acoustic sources to be examined. This may be useful for future noise reduction studies.
Metanicotine: A nicotinic agonist with central nervous system selectivity—in vitro and in vivo characterization

A growing body of evidence suggests that disruption of nicotinic cholinergic systems may be an important factor in the etiology of a number of different diseases, ranging from neurodegenerative diseases, such as Alzheimer's and Parkinson's, to ulcerative colitis. The mechanistic basis for such diverse nicotinic effects is likely to lie in the ever growing number of potential receptor subtypes. Therefore, the development of receptor subtype‐selective probes is essential to understand the emerging complexity of nicotinic cholinergic systems and the mechanisms underlying diseases that may involve these systems. Toward this end, we have evaluated the nicotinic agonist metanicotine, (E)‐N‐methyl‐4‐(3‐pyridinyl)‐3‐butene‐1‐amine, using the following in vitro and in vivo methods: 1) receptor binding and up‐regulation, 2) neurotransmitter release and ion flux in synaptosomes/cells, 3) in vivo microdialysis in rats, 4) reversal of scopolamine‐induced amnesia in a step‐through passive‐avoidance paradigm, 5) water maze performance in mice, 6) radial‐arm maze performance in brain‐lesioned rats, 7) changes in heart rate and blood pressure, and 8) physiological depression of body temperature, locomotor activity, acoustic startle, and respiration rate. Our in vitro results indicate that metanicotine binds with high affinity to the major receptor subtype in brain (α4β2), evokes dopamine release from striatal synaptosomes and Rb+ efflux from thalamic synaptosomes, but does not activate ganglionic, muscle, or other peripheral type nicotinic receptors. These results suggest that metanicotine is selective for α4‐containing central nervous system (CNS) nicotinic receptors and has reduced selectivity for peripheral nervous system (PNS) receptor subtypes. These conclusions are further supported by in vivo studies with metanicotine showing enhanced cognitive effects and significantly lower peripheral effects. Our in vivo results indicate that metanicotine increases the release of acetylcholine, norepinephrine, dopamine, and serotonin in cortex and is equal to or better than nicotine on measures of cognitive enhancement. By comparison, metanicotine is significantly less potent than nicotine in increasing heart rate and blood pressure and in causing physiological depression. These results are consistent with in vitro data indicating metanicotine's CNS receptor selectivity, and they suggest that this ligand may be a suitable tool for probing the relationships that underlie the complex central and peripheral pharmacology of nicotinic cholinergic systems. Furthermore, metanicotine may be a good lead candidate for developing nicotinic agonists as CNS therapeutics with reduced peripheral side effects. Drug Dev. Res. 38:169–176 © 1996 Wiley‐Liss, Inc.
Phylogeny and Generic Delimitation of the Metalasia Clade (Asteraceae-Gnaphalieae)

The Metalasia clade, which consists of the genus Metalasia and a number of much smaller satellite genera, is a South African group in the tribe Gnaphalieae (Asteraceae). This study scrutinizes the phylogenetic relationships of the Metalasia clade by means of chloroplast (trnL-trnF, psbA-trnH) and nuclear (external transcribed spacer, internal transcribed spacer) sequence data. The Metalasia clade is confirmed to be a monophyletic group, and the phylogenetic positions of the included genera are determined. The genus Metalasia may be monophyletic if the monotypic Planea is included, but the node has very poor support and further studies are needed. The Metalasia species fall into two well-supported groups, distinguishing the members of Karis’s Metalasia densa group from the others. Lachnospermum is shown to be monophyletic and is placed as a possible sister group to Metalasia. Phaenocoma is placed as sister to the branch consisting of Metalasia and Lachnospermum. Calotesta, Hydroidea, and Atrichantha form a clade, with the monotypic Dolichothrix as their sister group.
An Efficient Authentication and Key Agreement Scheme Based on ECDH for Wireless Sensor Network

Wireless sensor networks (WSN) consist of a large number of resource-constrained sensor nodes, different types of controls, and gateway nodes. these kinds of networks are used as control systems and remote monitoring in industries such as health care, defense, agriculture, and disaster management. Due to the widespread use of wireless sensor networks, valuable information is exchanged between network entities such as sensors, gates, users, etc. in an unsafe channel, and the presence of important and sensitive information in the network increases the importance of security issues. In this article, we analyzed Majid Alotaibi schema and identify some security breaches in this article. We have also described a security attack against the proposed protocol based on security problems. In addition, to address the security issues of M. Alotaibi proposed protocol, we have introduced a mutual authentication and key agreement protocol based on ECDH (elliptic-curve Diffie–Hellman). We have implemented our own method using the Scyther tool, manually reviewed its security features and also compared it with other methods.
Association of Aeromonas hydrophila with epizootic ulcerative syndrome (EUS) of freshwater fish in Sri Lanka

Summary Aeromonas hydrophila was the predominant bacteria isolated from the haemorrhagic lesions and necrotic ulcers in the seven species of fish, Etroplus suratensis, Ophicephalus striatus, Puntius sarana, Rasbora danicornius, Trichogaster pectoralis, Tor khudree lonispinnis and Wallago attu affected by eizootic ulcerative syndrome(EUS), during the 1990 and 1991 disease outbreaks in Sri Lanka. Severely affected fish were truly septicemic, as A. hydrophila was recovered from their internal organs. A. hydrophila isolated from diseased fish and injected intramuscularly into healthy E. suratensis and O. striatus induced dermonecrotic lesions resemblin EUS. The results suggests that A. hydrophila is consistently associated with EUS in Sri Lanka anf may play an important role in the patlogenesis of the disease.
HERITABILITY AND GENETIC ADVANCE OF HULL PEELING IN TWO-ROW BARLEY

Two populations, developed from three two-rowed malting barley (Hordeum vulgare L.) lines, were used to estimate the heritability, variability, and genetic advance of hull peeling in 1985 and 1986 at Saskatoon, Canada. The populations were Harrington/Ellice and Harrington/WM797-83. In both populations, estimates of heritability were relatively low to moderate. Coupled with the high variability found within the parental lines, it was concluded that hull peeling is largely an environmentally influenced trait. Estimates of genetic advance indicated that moderate gains could be achieved with stringent selection pressure (5%) against hull peeling. A great deal of variability was found within the F3 and F4 generations indicating potential for improvement through selection. Based on results obtained, selection for hull adherence would best be incorporated into the later generations of an already established breeding program.Key words: Barley, heritability, genetic advance, hull peeling, Harrington, Hordeum vulgare
Structural and biochemical characterization of nsp12-nsp7-nsp8 core polymerase complex from COVID-19 virus

The ongoing global pandemic of coronavirus disease 2019 (COVID-19) has caused huge number of human deaths. Currently, there are no specific drugs or vaccines available for this virus. The viral polymerase is a promising antiviral target. However, the structure of COVID-19 virus polymerase is yet unknown. Here, we describe the near-atomic resolution structure of its core polymerase complex, consisting of nsp12 catalytic subunit and nsp7-nsp8 cofactors. This structure highly resembles the counterpart of SARS-CoV with conserved motifs for all viral RNA-dependent RNA polymerases, and suggests the mechanism for activation by cofactors. Biochemical studies revealed reduced activity of the core polymerase complex and lower thermostability of individual subunits of COVID-19 virus as compared to that of SARS-CoV. These findings provide important insights into RNA synthesis by coronavirus polymerase and indicate a well adaptation of COVID-19 virus towards humans with relatively lower body temperatures than the natural bat hosts.
Emergence of multiple variants of SARS-CoV-2 with signature structural changes

This study explores the divergence pattern of SARS-CoV-2 using whole genome sequences of the isolates from various COVID-19 affected countries. The phylogenomic analysis indicates the presence of at least four distinct groups of the SARS-CoV-2 genomes. The emergent groups have been found to be associated with signature structural changes in specific proteins. Also, this study reveals the differential levels of divergence patterns for the protein coding regions. Moreover, we have predicted the impact of structural changes on a couple of important viral proteins via structural modelling techniques. This study further advocates for more viral genetic studies with associated clinical outcomes and hosts’ response for better understanding of SARS-CoV-2 pathogenesis enabling better mitigation of this pandemic situation.
Membrane voltage dysregulation driven by metabolic dysfunction underlies bactericidal activity of aminoglycosides

Aminoglycosides are broad-spectrum antibiotics whose mechanism of bactericidal activity has been under debate. It is widely accepted, however, that membrane voltage potentiates aminoglycoside activity, which is ascribed to voltage dependent drug uptake. In this paper, we measured the single cell response of Escherichia coli treated with aminoglycosides and discovered that the bactericidal action arises not from the downstream effects of voltage dependent drug uptake, but rather directly from dysregulated membrane potential. In the absence of voltage, aminoglycosides are taken into cells and exert bacteriostatic effects by inhibiting translation. However, cell killing was immediate upon re-polarization. The hyperpolarization arose from altered ATP flux, which induced a reversal of the F1Fo-ATPase to hydrolyze ATP and generated the deleterious voltage. Heterologous expression of an ATPase inhibitor from Salmonella completely eliminated bactericidal activity, while loss of the F-ATPase significantly reduced the electrophysiological response to aminoglycosides. Our data support a model of voltage induced death, which could be resolved in real-time at the single cell level, and separates the mechanisms of aminoglycoside bacteriostasis and bactericide in E. coli.
Experimental evolution of virulence and associated traits in a Drosophila melanogaster – Wolbachia symbiosis

Evolutionary theory predicts that vertically transmitted symbionts are selected for low virulence, as their fitness is directly correlated to that of their host. In contrast with this prediction, the Wolbachia strain wMelPop drastically reduces its Drosophila melanogaster host lifespan at high rearing temperatures. It is generally assumed that this feature is maintained because the D. melanogaster–wMelPop symbiosis is usually not exposed to environmental conditions in which the symbiont is virulent. To test this hypothesis, we submitted wMelPop-infected D. melanogaster lines to 17 generations of experimental evolution at a high temperature, while enforcing late reproduction by artificial selection. The fly survival was measured at different time points, as well as two traits that have been proposed to be causally responsible for wMelPop virulence: its relative density and the mean number of copies of octomom, an 8-genes region of the Wolbachia genome. We hypothesised that these conditions (high temperature and late reproduction) would select for a reduced wMelPop virulence, a reduced wMelPop density, and a reduced octomom copy number. Our results indicate that density, octomom copy number and virulence are correlated to each other. However, contrary to our expectations, we could not detect any reduction in virulence during the course of evolution. We discuss the significance of our results with respect to the evolutionary causes of wMelPop virulence.
Short-Term Reliability Assessment of Generating Systems Considering Demand Response Reliability

Demand response (DR), one kind of flexible resources, can decrease the operating costs of power systems and improve their reliability. However, DR is not absolutely reliable due to its inherent uncertainty, so its function of improving system reliability is restricted. In order to estimate the risk of generating systems during the period of DR events, the short-term reliability assessment of generating systems considering DR reliability is studied in this paper. Firstly, a multi-state continuous-time Markov chain (CTMC) model of DR response capacity is established and the state division of response capacity is performed by the method of mean-standard deviation (MSD) classification. Secondly, the transition matrix of DR response capacity is estimated according to the sequence of DR response capacity. Thirdly, the CTMCs of demand response providers’ (DRP) response capacity and those of generating units’ (GU) output capacity are converted into universal generating functions (UGF) by Lz-transform. Finally, the transient distribution of DR response capacity and GU output capacity are derived, and the short-term reliability assessment method for generating systems considering DR reliability is proposed. A case study on a revised IEEE-RTS79 system shows the application of the presented method. The method proposed in this paper can assist system operators to evaluate the reliability of generating systems during the period of DR events.
Assessment of the South African hake resource taking its two-species nature into account

The commercially valuable hake fishery off South Africa consists of two morphologically similar species, the shallow-water Cape hake Merluccius capensis and the deep-water Cape hake M. paradoxus. Because catch-and-effort statistics collected from the fishery are not species-disaggregated, previous published quantitative assessment methods have treated the two hake species as one. Furthermore, recent evidence suggests that (although treated as two separate populations in past assessments) the South and West coasts components of each species form a single stock. This paper describes the development of the first fully species-disaggregated coast-wide baseline assessment of the South African hake resource. M. paradoxus is estimated to be currently at <10% of its pre-exploitation level whereas M. capensis is estimated to be well above its maximum sustainable yield level. By taking into consideration the primary sources of uncertainty in this assessment, a Reference Set of 24 operating models is developed to be used in Operational Management Procedure testing.
A new Approach for Parameter Estimation of Power System Equipment Models

Modeling and simulation are of great importance in power systems studies. In order to ensure the accuracy of the results, model validation is performed. This paper presents a new approach using the Particle Swarm Optimization (PSO) algorithm for governor parameter estimation and identification. To estimate unknown parameters, the system frequency and turbine power signals following several events are used. In the proposed method, to recognize the most effective parameters in each event, a sensitivity analysis technique is applied. Next, the most influential intervals that parameters have greater impact on system response are selected. The unknown parameters are then estimated using the selected time intervals. The proposed technique is tested on IEEE 9-bus test system using DIgSILENT power factory software. Studies' results demonstrate the efficiency of the proposed technique especially in reducing the computation burden and obtaining faster convergence.
Customer feedback provision in online labor platforms: an application of the theory of planned behavior

Customers have been increasingly making use of online labor platforms such as Airbnb, Uber, and Postmates, rising in popularity with the prevalence of online resources, technology, and applications for crowdsourcing. This type of business model results in the need for proper quality management of service providers and adequate information upon which customers base their buying decisions. Online labor platforms thereby rely on feedback from customers to effectively manage their service providers and uphold the platform’s community of trust, but this feedback provision is entirely voluntary by customers. This paper provides an application of the theory of planned behavior in attempt to gain an understanding of what drives customers to participate in feedback provision in a setting where a pattern of doing so is crucial to the survival and success of the platform but is simultaneously completely voluntary. A survey of 142 Airbnb users was analyzed to test three hypotheses related to posited effects within the theory of planned behavior, including the prediction that attitudes toward feedback provision would have the greatest effect on intention to provide feedback. Findings show that the theory of planned behavior is insufficient in predicting customer feedback provision behavior in the context of online labor platforms in that hedonic attitudes were the only significant predictor of intention to provide feedback, and subjective norms were the only significant predictor of actual feedback provision.
Comparison of developmental genome expression in rodent molars reveals extensive developmental system drift

In evolution, it is widely believed that phenotypic changes root in developmental changes and phenotype conservation, in developmental conservation. Seeming phenotype conservation may however hide evolutionary changes in the underlying developmental mechanisms by which a trait is produced. This cryptic evolution is also called Developmental System Drift, and the extent of this phenomenon unclear. We used a well-characterized evo-devo model system, rodent molars, to test the correlation between phenotypic and developmental evolution. Between mouse and hamster, the morphology of the lower molars has much less diverged than the morphology of the upper molars. Is development accordingly more conserved? We compared molar crown formation with a standard approach, and with a tight transcriptome time-series to get a quantitative molecular profiling of developmental states. Our data identify common trends in the development of all molars. Upper and lower molars have their specificities since the early steps of morphogenesis, at the levels of the pattern of cusp formation, cellular composition and biased gene expression. The extent of difference in lower vs. upper molar development within one species does correlate with the extent of difference in final morphology. However, the specificity of lower vs. upper molar development is drowned among the rapid evolution of development, which is highly species-specific in term of expression levels and temporal profiles. Divergence in developmental systems is almost as high for lower as it is for upper molar, despite much lesser morphological changes in lower molar crown. Hence, our results point an extensive drift in this developmental system. Because serial organs are largely sharing gene networks, it supports previous theoretical work that suggest a causal link between pleiotropy and DSD.
Comparison of gait variability and stability indices

Indices of variability and stability are essential in evaluating the motions of the human gait. Owing to the inconsistent results of earlier studies, the relationships among popular indices, i.e., maximum Lyapunov exponent (λ), MeanSD, and long-range correlation (α), are inconclusive. In this study, we examined the correlations among these indices using the velocity of the center of body mass for 10 participants walking on a treadmill. In terms of the velocity along the gravitational direction, MeanSD exhibited a negative correlation with the short-term λS and the long-term λL when the walking speed was 4.0 km/h. Although a positive correlation between MeanSD and λ is expected based on the meanings of these indices, the present and earlier studies collectively suggest that there is no positive correlation between MeanSD and λ. In the same direction, a positive correlation was found between λS and α when the walking speed was 3.5 km/h. MeanSD and α tended to exhibit a negative correlation for some conditions, which is reasonable because MeanSD and α indicate the level of variability and the long-term consistency of walking, respectively.
Ecologia de comunidades de insetos bentônicos (Ephemeroptera, Plecoptera e Trichoptera), em córregos do parque ecológico de Goiânia, Goiás, Brasil

Relationships among some abiotic factors (temperature, velocity, flow, conductivity, oxy-reduction potential and pH) and the seazonal density of benthic insects (immature forms) of the orders Ephemeroptera, Plecoptera and Trichoptera at the Parque Ecologico de Goiânia, Goias are studied. An area of 1m2 was sampled and abiotic factors were recorded in 4 sites from August/1994 to July/1995. The faunistic composition was 75% Ephemeroptera, 1% Plecoptera and 24% Trichoptera. The data suggest the water velocity and flow as the main factors that determined the aquatic insects abundance.