Physics homework often boils down to solving end-of-chapter quantitative problems. For targeting different learning goals of physics education, different types of homework are needed. The aim of this research was to compare the effectiveness of simulation-based, video-based, and paper-and-pencil homework in developing an understanding about Newton’s laws and forming positive attitudes towards physics homework. 150 first-year students from the Faculty of Chemical Engineering and Technology at the University of Zagreb (Croatia) were randomly assigned to one of the three above-mentioned homework approaches. After, students had lectures and seminars on Newton’s laws, they were administered a pre-test. In the next three weeks, the students completed three homework assignments on Newton’s laws, after which they completed a post-test. For students from all three homework approaches a substantial improvement in conceptual understanding has been observed. Although the three approaches proved to be equally effective when it comes to developing understanding, the simulation-based approach was found to be superior when it comes to developing positive attitudes towards physics homework. If one controls for target knowledge, the modality of the homework assignment does not affect cognitive outcomes, but it does affect students’ attitudes towards homework. Keywords: conceptual understanding, experimental study, simulation-based homework, video-based homework
Battery management systems (BMS) are becoming increasingly important in the modern age, where clean energy awareness is getting more prominent. They are responsible for controlling large battery packs in modern electric vehicles. Today, conventional solutions rely only on a wired design, which adds manufacturing cost and complexity. Recent research has considered wireless solutions for the BMS. However, it is still challenging to develop a solution that considers both the active in-vehicle and the external second-life applications. The battery passport initiative aims to keep track of the batteries, both during active and inactive use cases. There is a need to provide a secure design while considering energy and cost-efficient solutions. We aim to fill this gap by proposing a wireless solution based on near-field communication (NFC) that extends previous work and provides a unified architecture for both use cases. To provide protection against common wireless threats, an advanced security analysis is performed, as well as a system design analysis for the wake-up process that reduces the daily power consumption of the stored battery packs from milli- to microwatts.
Significance Ion channels that employ carboxylic residues in their selectivity filters (SFs) are found in many realms of life and are important in essential physiological processes. We study bacterial Nav channels which employ four glutamic acid residues in their SF, and we propose a different view of how ion channel selectivity is achieved in nature, based on the difference in pKa values of the SF glutamates in the presence of different ion types. Because of the observed sensitivity of pKa values on the geometry of the SF, this could be important in other channels with carboxylic residues in the SF, e.g., voltage-gated Ca2+ channels, and could possibly explain the large variety in observed selectivities of such channels.
Bacterial conjunctivitis is a common condition in paediatric ophthalmology. Incidence and symptoms depend on etiological factor, clinical presentation and age. The most common pathogens which cause bacterial conjunctivitis are: Staphylococcus aureus, Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis etc. Conjunctivitis is treated empirically in most cases, the treatment is defined by symptoms and clinical findings, physician prescribes the available antibiotic treatment. Eye swab is indicated in cases of prolonged or non efficient treatment or in case of relapse. Goals: To evaluate bacterial conjunctivitis according to microbial pathogen detected in eye swab, the most common microbial pathogens found and drug susceptibility of antimicrobial agents given in antibiogram. Methods: We retrospectively evaluated 73 microbiological findings of eye swabs in 53 children between January 2019 and March 2020. The sample was cultured on blood and chocolate Gram staining agar incubated under 5-10% CO2, 35-37ËšC with daily reading 40-48h. Bacteria collected from eye swabs were tested for the following antibiotics: chloramphenicol, ciprofloxacin, gentamicin, moxifloxacin, ofloxacin, trimethoprim/sulfamethoxazole, tetracycline, erythromycin, ampicillin, azithromycin, amoxicillin, clindamycin and penicillin. Results: In a total of 53 patients eye swabs were taken, 23(43,39%) male and 30(56,60%) female, age ranged from 0-17 (mean age 32,3±52,3 months or 2,7±4,4 years) most common patient age was 2 years in 40(75,5%) cases. Number of performed eye swabs was 73, and pathogens were isolated in 70(95,9%) cases, and only in 3(4,1%) cases there were no pathogens in eye swab, meaning that indication for eye swab was highly justified. Among isolated pathogens, Staphylococcus aureus was proved to be the most common, in 20(27,4%) cases, the antibiotic with highest drug susceptibility was chloramphenicol in 33(62,3%) cases. Conclusion: Microbiological evaluation of bacterial conjunctivitis is reasonable in moderate to severe cases associated with mucopurulent discharge, prolonged treatment, and as confirmation of diagnosis. Choosing the accurate antibiotic therapy requires identification of pathogen and assessing its susceptibility. Targeted treatment reduces risk of antibiotic overdosing or unnecessary use of antibiotics. Prudent use of antibiotics reduces antimicrobial resistance.Â
More environment-friendly solvents in analytical chemistry are almost inevitable in both sample preparation and analysis to meet the high standards of sustainable chemistry and human welfare. In this review paper, a critical look at the advantages and still unsolved problems of most potential classes of green solvents is presented to give an overview of the current state-of-the-art in this field. Replacing volatile organic compounds (VOCs) by ecofriendly and benign solvents in extractions/separations in sample preparation, as the most tedious and demanding step in analysis, is one of roads toward sustainable chemistry. Water under sub- and supercritical conditions, carbon-dioxide, ionic liquids (ILs), deep eutectic solvents (DESs), and those of natural origin (NADES) belong to the most promising classes of solvents in green analytical chemistry. Basic theory and mechanisms of their use illustrated by representative but not exhaustive list of examples related to complex matrices (environmental and natural food products) from analytical practice are presented in this review. Perspectives of QuEChERS, in line with GAC principles, are highlighted, in line with current trends of "going green" for quick, easy, cheap, effective, rugged, and safe analytical methods. Compliance with green chemistry (GC), especially green analytical chemistry (GAC) principles, is not a fashionable issue but, more the trend toward a sustainable future with greener chemistry; thus, green metrics are an unavoidable tool to measure how green the applied method or procedure is. Herein, the most common tools will be presented and discussed, such as national environmental method index (NEMI), analytical ecoscale, green analytical procedure index (GAPI), analytical greenness calculator (AGREE), complementary green analytical procedure index (ComplexGAPI), and analytical greenness metric for sample preparation (AGREEprep). The future trends for research and development in this still expanding field are presented in a critical view of advantages and disadvantages as well as improvement of the validation of analytical procedures. The creation of new certified reference materials (CRMs) and validated methods for specified analytes in complex matrices is a demanding task in the coming years. Tailor-made solvents with physicochemical properties for intended use are required for the selective extraction and separation and open numerous possibilities and huge potential for future research and industrial applications.
The production of raspberry (Rubus idaeus L.) as one of the most promising branches of fruit growing in Bosnia and Herzegovina could be permanently endangered due to the increasing incidence of crown gall disease caused by Agrobacterium tumefaciens. The aim of this paper was to examine the morphological changes on raspberry seedlings caused by the bacterium A. tumefaciens, as well as the size and number of tumors depending on the applied biological or chemical treatment. The strain Agrobacterium tumefaciens MTCC 431 (ATCC 15955) was used. Morphometric parameters on raspberry seedlings were measured using the ImageJ 1.48v program. A binocular magnifier at 20x magnification was used to measure the the gook diameter. The computer program R c. 3.4.0 was used for a statistical analysis of results and an analysis of main components. It was observed that the raspberries inoculated with A. tumefaciens had a lower growth potential when compared to the control line. Rhizobium rhizogenes strain K1026, as an active substance of biopesticide, had a positive effect on the growth of infected raspberry plants, reducing bacterial infection. The applied chemical agent based on copper (I) oxide demonstrated lesser impact on the intensity of A. tumefaciens infection when compared to the biological agent. In this paper, a lower intensity of changes in raspberry plants was observed when the biopesticides and fungicides were applied simultaneously, in comparison with the individual treatments.
Izvještaj sa Naučnog projekta “HISTORIJSKI POGLEDI 2022”, Centar za istraživanje moderne i savremene historije Tuzla, Tuzla, 18. i 19. novembar 2022. godine // Conference Report from Scientific project “HISTORICAL VIEWS 2022”, Center for Research of Modern and Contemporary History Tuzla, Tuzla, November 18 and 19, 2022.
Background: The coronavirus disease (Covid 19) is caused by the SARS-CoV-2 virus. The virus has spread globally, causing millions of deaths.Aim: This study was made with the aim of revealing the clinical features of corona virus infection, as well as assessing the prevalence of comorbidities in patients infected with coronavirus 2 (SARS-CoV-2).Methods: In this analysis the data was obtained from the hospital information system, involving patients who were treated for Covid-19, in the period January 1 until April 8, 2021.Results: 400 infected patients were included in the study, 86.2% of whom had comorbidities, and 8.8% without comorbidities. The results showed that the most common clinical symptom is fever in 62%, followed by difficulty breathing in 53%, and cough in 42%. The most prevalent comorbidities were cardiac 68.3%, then endocrinological 33.8%, surgical 16.5%, neurological 15%, oncological 12%, nephrological 11%, and pulmonary 10%. The existence of a significant association between the presence of comorbidities and the patients suffering from COVID-19 on mechanical ventilation due to treatment complications was determined, p=0.000 (p<0.05) at the 95% significance level.Conclusion: We assessed the prevalence of comorbidities in patients with COVID-19 and found that underlying disease, including cardiac and endocrinological diseases, may be a risk factor for severe forms of the disease.Key words: Covid-19, clinical features, comorbidities
These are the lecture notes for an introductory course on black holes and some aspects of their interaction with the classical and quantum world. The focus is on phenomena of"fundamental physics"in the immediate surroundings of the black hole (classical and quantum fields, with little astrophysics). We aim more at qualitative, intuitive understanding than at quantitative rigor or detail. Accordingly, we only assume previous exposure to a conventional introduction to the elements of General Relativity and a glancing acquaintance with the Schwarzschild solution, but not more. We use many figures for illustrations and provide a set of carefully guided exercises. Topics: (1) The black hole as a tale of light and darkness. (2) The black hole that vibrates. (3) The black hole that rotates. (4) The black hole that evaporates. (A) Guided problems.
By sharing local sensor information via Vehicle-to-Vehicle (V2V) wireless communication networks, Cooperative Adaptive Cruise Control (CACC) is a technology that enables Connected and Automated Vehicles (CAVs) to drive autonomously on the highway in closely-coupled platoons. The use of CACC technologies increases safety and the traffic throughput, and decreases fuel consumption and CO2 emissions. However, CAVs heavily rely on embedded software, hardware, and communication networks that make them vulnerable to a range of cyberattacks. Cyberattacks to a particular CAV compromise the entire platoon as CACC schemes propagate corrupted data to neighboring vehicles potentially leading to traffic delays and collisions. Physics-based monitors can be used to detect the presence of False Data Injection (FDI) attacks to CAV sensors; however, unavoidable system disturbances and modelling uncertainty often translates to conservative detection results. Given enough system knowledge, adversaries are still able to launch a range of attacks that can surpass the detection scheme by hiding within the system disturbances and uncertainty -- we refer to this class of attacks as \textit{stealthy FDI attacks}. Stealthy attacks are hard to deal with as they affect the platoon dynamics without being noticed. In this manuscript, we propose a co-design methodology (built around a series convex programs) to synthesize distributed attack monitors and $H_{\infty}$ CACC controllers that minimize the joint effect of stealthy FDI attacks and system disturbances on the platoon dynamics while guaranteeing a prescribed platooning performance (in terms of tracking and string stability). Computer simulations are provided to illustrate the performance of out tools.
The aim of the study was to evaluate rural households from five different regions of Bosnia and Herzegovina based on predetermined economic, ecological, and sociological criteria, using assessments from five expert professionals in the field. The study employed the fuzzy multi-criteria decision-making method called TOPSIS to ensure research accuracy. The results indicated that the rural household “Radoja” received the highest rating, which could serve as a solid foundation for future rural tourism development in Bosnia and Herzegovina. Based on the obtained results, it is possible to conduct future research in other regions of the country, providing appropriate guidelines for the development of rural tourism in Bosnia and Herzegovina.
The paper extends the concept of universal motion controller (UMC), by introducing an adaptive mechanism in the original form. The adaptive universal motion controller (AUMC) allows superior position tracking in free motion by allowing better utilization of available control resources. AUMC, as well as UMC, allows concurrent position and force control with a single control structure. Thus, it can be used for trajectory tracking in free motion and also for the interaction force control. This control strategy is of essential importance for the growing field of human-robot interaction (HRI) applications.
Abstract The aim of this study was to evaluate antioxidative features using 2,2-diphenyl-1-pycrylhydrazyl free radical (DPPH•) scavenging method, bovine serum albumin (BSA)-binding properties with usage of spectrofluorimetric method, proliferative and cyto/genotoxic status by use of chromosome aberration test, and antimicrobial potential using broth microdilution method, followed by resazurin assay of benzyl-, isopropyl-, isobutyl and phenylparaben in vitro. Our results showed that all parabens had significant antiradical scavenger activity compared to p-hydroxybenzoic acid (PHBA) precursor. Higher mitotic index for benzyl-, isopropyl and isobutylparaben (250 µg/mL) in comparison with control was demonstrated. An increase in the frequency of acentric fragments in lymphocytes treated with benzylparaben and isopropylparaben (125 and 250 µg/mL), and isobutylparaben (250 µg/mL) was observed. Isobutylparaben (250 µg/mL) induced higher number of dicentric chromosomes. An increased number of minute fragments in lymphocytes exposed to benzylparaben (125 and 250 µg/mL) was found. A significant difference in the frequency of chromosome pulverization, between phenylparaben (250 µg/mL) and control, was detected. Benzylparaben (250 µg/mL) and phenylparaben (62.5 µg/mL) caused an increase in the number of apoptotic cells, while isopropylparaben (62.5, 125 and 250 µg/mL) and isobutylparaben (62.5 and 125 µg/mL) induced higher frequency of necrosis. Minimum inhibitory concentration (MIC) of tested parabens ranged 15.62–250 µg/mL for bacteria, and 125–500 µg/mL for the yeast. Minimum microbiocidal concentration ranged 31.25 to 500 µg/mL, and 250 to 1000 µg/mL in bacteria and fungi respectively. The lowest MICs for bacteria were observed for phenyl- (15.62 µg/mL) and isopropylparaben (31.25 µg/mL) against Enterococcus faecalis.
This paper explores the “lost language” of monuments erected in the former Yugoslavia from the 1960s to the 1980s—more precisely, the 25 national monuments captured by the lens of photographer Jan Kempenaers over the span of three years (2006−2009), and published in the monograph Spomenik [Monument] (2010). By combining the approach of cognitive linguistics and cultural studies, in particular that of Forceville (“Identifi cation”, “Metaphor”, “Agendas”), Kövecses (Culture, Context), Ortiz, and Kirn and Burghardt, this paper aims to explore the conceptual metaphors embedded in these monuments as part of a specifi c symbolic landscape, immanent to the countries of the former Yugoslavia at a historical point of their four-decades-long political, social, and cultural merger, as well as the current possibilities and limitations of the visual/multimodal decodifi cation of the memorials.
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