45 research outputs found

    DEVELOPING VALUES FOR SECONDARY SCHOOL STUDENTS THROUGH THE STUDY OF ART OBJECTS

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    The paper begins with some issues related to aesthetics, aesthetic education, art and axiological education. The empirical research has the general assumption that secondary school students and youth have difficulties in selecting values. The objective of the research was three fold: to design, to organize and to carry learning activities from which students shall acquire educational values through the study of art objects. The exploratory research was conducted on a sample of 50 students (25 in experimental group and 25 in control group). The content sample included fairy-tales and short stories (Beauty and the Beast; The money earned by Alexandru Mitru) and artistic topics on several well-known art objects (The Endless Column, Table of Silence, The Gate of Kiss, Peleş castle, Voroneţ monastery, and St. Michael’s Cathedral from Cluj-Napoca). The tested hypothesis stated that if secondary school students are involved in learning contexts where they perceive, analyze and explain artistic objects then they develop aesthetic and ethic values. The learning context students were exposed to represents the independent variable and the outputs – the educational values themselves – represent the dependent variable. In order to test for the hypothesis we planned a formative didactic experiment. In order to test the hypothesis the pre-test/post-test design was used

    On Structure-Preserving Cryptography and Lattices

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    The Groth-Sahai proof system is a highly efficient pairing-based proof system for a specific class of group-based languages. Cryptographic primitives that are compatible with these languages (such that we can express, e.g., that a ciphertext contains a valid signature for a given message) are called structure-preserving . The combination of structure-preserving primitives with Groth-Sahai proofs allows to prove complex statements that involve encryptions and signatures, and has proved useful in a variety of applications. However, so far, the concept of structure-preserving cryptography has been confined to the pairing setting. In this work, we propose the first framework for structure-preserving cryptography in the lattice setting. Concretely, we - define structure-preserving sets as an abstraction of (typically noisy) lattice-based languages, - formalize a notion of generalized structure-preserving encryption and signature schemes capturing a number of existing lattice-based encryption and signature schemes), - construct a compatible zero-knowledge argument system that allows to argue about lattice-based structure-preserving primitives, - offer a lattice-based construction of verifiably encrypted signatures in our framework. Along the way, we also discover a new and efficient strongly secure lattice-based signature scheme. This scheme combines Rückert\u27s lattice-based signature scheme with the lattice delegation strategy of Agrawal et al., which yields more compact and efficient signatures. We hope that our framework provides a first step towards a modular and versatile treatment of cryptographic primitives in the lattice setting

    Decoding LTFs in the Generic Group Model

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    Lossy trapdoor functions (LTFs) constitute a useful and versatile cryptographic building block. LTFs have found applications in various types of encryption schemes, are closely connected to statistically secure oblivious transfer protocols, and have led to the first constructions of group-based trapdoor functions. However, with one recent exception, all known group-based LTFs are comparatively inefficient, and in particular suffer from large images. In this work, we attempt to explain this inefficiency, and derive lower bounds for the image size of group-based LTFs. In essence, we find that purely algebraic group-based LTFs (i.e., LTFs that use the underlying group in a generic way, without considering group representations) must suffer from a large image size (of an at least super-constant number of group elements). Our results also help to explain the mentioned exceptional group-based LTF with compact images

    Analysing the spatio-temporal evolution of built-up area in Bistrita subcarpathian valley using G.I.S techniques

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    The goal of the study is to develop an appropriate method for analyzing and quantifying the territorial expansion of built-up area in the administrative territory of Bistrita subcarpathian Valley, a well populated region. The area under study has high favorability in terms of housing due to its contact geographical unit position and access to natural resources. Analyzing spatio-temporal dynamics of built-up area is essential for understanding and assessing the consequences of anthropogenic pressure on the environment. The methodology was mainly achi sved through GIS techniques, by using relevant cartographic documents covering a period of more than 200 years. As a particular method we created a system of matrices (focalsum) which divide the areas affected by changes into equal size squares in order to highlight the density of these changes. The study was conducted through a systemic approach, aiming to analyze the connections between the territo: ial expansion and the environmental components which constituted key factors to its dynamics. The results showed a continuous and rapid expansion of built-up area, With different growth patterns depending on the socioeconomic factors, which represented the dominant driving factors of this phenomeno

    Analysing the spatio-temporal evolution of built-up area in Bistrita subcarpathian valley using G.I.S techniques

    Get PDF
    The goal of the study is to develop an appropriate method for analyzing and quantifying the territorial expansion of built-up area in the administrative territory of Bistrita subcarpathian Valley, a well populated region. The area under study has high favorability in terms of housing due to its contact geographical unit position and access to natural resources. Analyzing spatio-temporal dynamics of built-up area is essential for understanding and assessing the consequences of anthropogenic pressure on the environment. The methodology was mainly achi sved through GIS techniques, by using relevant cartographic documents covering a period of more than 200 years. As a particular method we created a system of matrices (focalsum) which divide the areas affected by changes into equal size squares in order to highlight the density of these changes. The study was conducted through a systemic approach, aiming to analyze the connections between the territo: ial expansion and the environmental components which constituted key factors to its dynamics. The results showed a continuous and rapid expansion of built-up area, With different growth patterns depending on the socioeconomic factors, which represented the dominant driving factors of this phenomeno

    Synthesis of graphene /CuGaO2 aerogels for advanced electrodes

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    Inorganic aerogels [1] are most often produced from silica, undergoing multiple phases of cooling and heating under high pressure (supercritical drying) or vacuum (lyophilization). Nowadays, low-cost organic aerogels such as graphene/metal oxide hydrogels are widely used in various applications (supercapacitors, oil absorption etc.) and fields like electronics, material science and aerospace engineering [2,3]. These carbon-based nanomaterials, having a nonpolar carbon structure, are useful especially for their essential hydrophobic properties [4], ultralow density, high surface area and high conductivity. Our previous work [5,6] included studies upon p-CuGaO2 dye-sensitized solar cells which revealed excellent optical transparency of CuGaO2. Also, CuGaO2 can be used in photocatalysis for the oxidation of hydrogen sulfide, while graphene can conduct the electrons generated in the conduction band of the semiconductor to the counter-electrode closing the electrical circuit. Hybrid materials like CuGaO2/graphene aerogels could be efficient for dyesensitized solar cells and advanced electrodes fabrication

    Studies on the hydrothermal synthesis of CdxZn1-x S compounds

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    In this study series of CdxZn1-xS solid solutions with different amounts of Cd and Zn were synthesized by the hydrothermal treatment of aqueous solutions containing CdCl2, Na2S · 9 H2O and ZnSO4 · 7 H2O. The aim was to examine the influence of Zn concentration and processing conditions (hydrothermal temperature and duration) on the structure of the obtained powders and their photocatalytic activity (in water splitting process). The obtained photocatalysts (with and without Pd co-catalyst) were analysed by X-ray diffraction (XRD), atomic absorption spectroscopy (AAS), ultraviolet-visible spectroscopy (UV-VIS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) method and gas chromatography (GC). The XRD results confirmed the crystallinity of the compounds and transition from hexagonal to cubic phase with increasing Zn content. Complete transformation from hexagonal to cubic phase did not take place, and both phases were present in almost all samples. BET analysis showed the importance of the pore distribution and pore size, especially in the case of photocatalysts with different duration treatment. GC measurements of the photocatalysts without and with Pd co-catalyst confirmed the production of hydrogen for all tested compounds. The best photocatalytic performance was achieved by the sample Zn50230/72-Pd prepared at 230 °C, for 72 hours, with 50% Zn and in the presence of Pd co-catalyst. The synthesis implied neither stabilizer nor organic compound

    Toxicity assessment of long-term exposure to non-thermal plasma activated water in mice

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    Non-thermal plasma activated water (PAW) has recently emerged as a powerful antimicrobial agent. Despite numerous potential bio-medical applications, studies concerning toxicity in live animals, especially after long-term exposure, are scarce. Our study aimed to assess the effects of long-term watering with PAWon the health of CD1 mice. PAWwas prepared from distilled water with a GlidArc reactor according to a previously published protocol. The pH was 2.78. The mice received PAW(experimental group) or tap water (control group) daily for 90 days as the sole water source. After 90 days, the following investigations were performed on the euthanatized animals: gross necropsy, teeth mineral composition, histopathology, immunohistochemistry, hematology, blood biochemistry, methemoglobin level and cytokine profile. Mice tolerated PAWvery well and no adverse effects were observed during the entire period of the experiment. Histopathological examination of the organs and tissues did not reveal any structural changes. Moreover, the expression of proliferation markers PCNA and Ki67 has not been identified in the epithelium of the upper digestive tract, indicating the absence of any pre- or neoplastic transformations. The results of our study demonstrated that long-term exposure to PAWcaused no toxic effects and could be used as oral antiseptic solution in dental medicine

    Directional turnover towards larger-ranged plants over time and across habitats

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    Species turnover is ubiquitous. However, it remains unknown whether certain types of species are consistently gained or lost across different habitats. Here, we analysed the trajectories of 1827 plant species over time intervals of up to 78 years at 141 sites across mountain summits, forests, and lowland grasslands in Europe. We found, albeit with relatively small effect sizes, displacements of smaller- by larger-ranged species across habitats. Communities shifted in parallel towards more nutrient-demanding species, with species from nutrient-rich habitats having larger ranges. Because these species are typically strong competitors, declines of smaller-ranged species could reflect not only abiotic drivers of global change, but also biotic pressure from increased competition. The ubiquitous component of turnover based on species range size we found here may partially reconcile findings of no net loss in local diversity with global species loss, and link community-scale turnover to macroecological processes such as biotic homogenisation

    Global maps of soil temperature

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    Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km2 resolution for 0–5 and 5–15 cm soil depth. These maps were created by calculating the difference (i.e. offset) between in situ soil temperature measurements, based on time series from over 1200 1-km2 pixels (summarized from 8519 unique temperature sensors) across all the world\u27s major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (−0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications
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