53,675 research outputs found
Primerjava dveh visokošolskih strokovnih študijskih programov predšolske vzgoje v Republiki Sloveniji in Republiki Severna Makedonija
No full textAntioxidant potential of bee pollen
No full textNamen magistrske naloge je bil določiti vsebnost skupnih fenolnih spojin, skupnih flavonoidov ter posameznih skupin flavonoidov in ugotoviti antioksidativni potencial (AOP) cvetnega prahu osmukanca. Zanimal nas je vpliv shranjevanja in sušenja cvetnega prahu na preiskovane lastnosti. Izvlečke fenolnih spojin smo pripravili s solventno ekstrakcijo z uporabo 96 % oz. 60 % etanola. AOP smo določili z metodo lovljenja prostega radikala DPPH∙ in z metodo beljenja β-karotena, ki temelji na sposobnosti zaviranja lipidne oksidacije v emulziji. V svežem cvetnem prahu osmukancu, kjer smo izvedli ekstrakcijo s 96 % etanolom, smo določili vsebnost skupnih fenolnih spojin 6-13 mg galne kisline/g suhe snovi in vsebnost flavonoidov 5-13 mg rutina/g suhe snovi. Izvlečki, ki smo jih pridobili s 96 % etanolom, so vsebovali manj skupnih fenolnih spojin in več skupnih flavonoidov od izvlečkov, pridobljenih s 60 % etanolom. Med skladiščenjem svežega cvetnega prahu osmukanca v hladilniku, se vsebnost skupnih fenolnih spojin ne spremeni, zmanjša se vsebnost skupnih flavonoidov. Med sušenjem se zmanjša vsebnost skupnih fenolnih spojin, predvsem flavonoidov. Eden od vzorcev je pokazal AOP, primerljiv z AOP galne kisline, ostali vzorci so bili slabši lovilci DPPH∙. V emulziji izvlečki cvetnega prahu osmukanca, ki smo jih pripravili s 96 % etanolom, kažejo večjo učinkovitost od izvlečkov, pripravljenih s 60 % etanolom. Izvlečki so v emulziji pokazali učinkovitost, primerljivo s sintetičnim antioksidantom butiliranim hidroksitoluenom.The purpose of this graduation thesis was to determine total phenolic content, total flavonoid content and individual groups of flavonoids, and to determine the antioxidative potential (AOP) of bee pollen. The extracts of phenolic compounds were prepared by the solvent extraction with 96 % and 60 % ethanol. AOP was determined with the DPPH∙ radical scavenging method and the method of bleaching β-carotene which is based on the ability to inhibit lipid oxidation in the emulsion. In fresh bee pollen where extraction with 96 % ethanol was used we determined the total phenolic content of 6-13 mg gallic acid/g of dry matter and total flavonoid content of 5-13 of rutin/g of dry matter. The extracts obtained with 96 % ethanol, contained less total phenolic compounds and more total flavonoids than the extracts obtained with 60 % ethanol. During storage of bee pollen in the refrigerator, the content of phenolic compounds remained unchanged, the content of total flavonoids decreased. During drying the content of phenolic compounds decreased, especially flavonoids. One of the samples showed AOP, which was comparable to AOP of gallic acid, other samples showed lower DPPH∙ scavenging activity. Extracts prepared with 96 % ethanol were more efficient in emulsion than those prepared with 60 % ethanol. In emulsion the extracts showed efficacy comparable to the synthetic antioxidant butylated hydroxytoluene
Antioxidant enzyme activity of filamentous fungi isolated from Livingston Island, Maritime Antarctica
No full textFrom 18 soil samples taken in the vicinity of the permanent Bulgarian Antarctic base "St. Kliment Ohridski" (62° 38 '29 "S, 60° 21’ 53’’ W) on Livingston Island, 109 filamentous fungi were isolated on selective media. The most widespread fungal species were members of the genera Cladosporium, Geomyces, Penicillium and Aspergillus. Other species, already recorded for Antarctic environments were also isolated: Lecanicillium muscarium, Epicoccum nigrum and Alternaria alternata. Thirty strains demonstrating good growth were screened for superoxide dismutase (SOD) and catalase (CAT) activities and 6 of them showed high enzyme activity. The tested strains produced SOD with higher activity at 15°C than at 30°C suggesting that this enzyme is cold-active. The best producer of cold-active SOD, A. glaucus 363 cultivated in bioreactors demonstrated optimal growth temperature at 25°C and maximum enzyme activities at 25°C and 30°C for SOD and CAT, respectively. The electrophoretical analysis showed that the fungus possesses Cu/Zn-SOD
Scientometric Portrait of Nobel Laureate S. Chandrasekhar
No full textScientometric analysis of the publications productivity of Nobel Laureate S. Chandrasekhar is documented
A study of discrete wavelet transform based denoising to reduce the effect of artificial light interferences for indoor optical wireless communication
No full textThe optical power penalty (OPP) due to the artificial light interferences (ALIs) can be significantly high in an indoor optical wireless communication (OWC) channel making such link practically infeasible. A discrete wavelet transform (DWT) is an effective technique in reducing the ALI effects. The DWT has the advantage over the high pass filtering (HPF) to reduce ALI in terms of complexity and performance. In this paper, a comprehensive study of the DWT based denoising for the on-off keying (OOK), pulse position modulation (PPM) and digital pulse interval modulation (DPIM) is provided. The OPPs due to ALIs and DWT based denoising for these modulation techniques are presented
Observations of Bºs→ψ(2S)η and Bº(s)→ψ(2S)π+π- decays
No full textFirst observations of the B0s
→ψ(2S)η, B0 →ψ(2S)π
+
π
− and B0s
→ψ(2S)π
+
π
− decays are made
using a dataset corresponding to an integrated luminosity of 1.0 fb−1 collected by the LHCb experiment in
proton–proton collisions at a centre-of-mass energy of
√
s = 7 TeV. The ratios of the branching fractions
of each of the ψ(2S) modes with respect to the corresponding J/ψ decays are
B(B0s
→ψ(2S)η)
÷
B(B0s
→J/ψη)
= 0.83± 0.14 (stat)±0.12 (syst) ±0.02 (B),
;
B(B0→ψ(2S)π
+
π
−
)
÷
B(B0→J/ψπ
+
π
−
)
= 0.56± 0.07 (stat)±0.05 (syst)± 0.01 (B),
;
B(B0s
→ψ(2S)π
+
π
−
)
÷
B(B0s
→J/ψπ
+
π
−
)
= 0.34± 0.04 (stat)±0.03 (syst)± 0.01 (B),
where the third uncertainty corresponds to the uncertainties of the dilepton branching fractions of the J/ψ
and ψ(2S) meson decays
Mýty a realita v procese s J. A. Baťom
No full textThe author of this paper deals with the retribution trial proceeding with J. A. Baťa, in 1947 at the National Court in Prague. Especially in recent years, questions related to this process raise again. There are many hypotheses that try to prove respectively point out the injustice and the political background of this case. Author argues against the violation of fundamental rights in criminal proceedings, procedural errors and predetermined and targeted punishment. The author looked at some of the most resonating hypothesis and tried to confirm or disprove its validity.Autorka sa v príspevku zaoberá retribučným procesom s J. A. Baťom, ktorý prebiehal v roku 1947 pred Národným súdom v Prahe. Najmä v posledných rokoch sa opäť vynárajú otázky, ktoré sa uvedeného procesu týkajú. Existuje veľké množstvo hypotéz, ktoré sa snažia dokázať resp. poukázať na nespravodlivosť a na politické pozadie konania. Polemizujú s porušovaním základných práv v trestnom konaní, s procesnými chybami a s vopred určeným a cieleným trestom. Autorka sa zamerala na niektoré, najviac rezonujúce hypotézy a snažila sa potvrdiť, či vyvrátiť ich správnosť
The Worldview and the Author´s (Self)Reflection in Czech Contemporary Historiography
No full textCílem studie je představit možnosti, jak na základě publikovaných autorských textů zkoumat světový názor historiků a historiček, zejména v oboru soudobých dějin, kde lze předpokládat vliv jejich hodnotového horizontu na interpretaci relativně nedávné minulosti. Autor nejprve vymezuje pojetí světového názoru vzhledem ke stanovenému záměru a zdůvodňuje analytické užití tohoto pojmu v historiografickém textu, v daném kontextu se také zamýšlí nad vztahem paměti, dějin a historiografie. Konstatuje, že poměrně málo českých historiků a historiček dosud reflektuje vztah (individuální či kolektivní) paměti a práce dějepisce, zvláště s ohledem na jeho pozici v současné společnosti, která bývá často redukována na roli objektivního „objevitele historické pravdy“. Taková (sebe)reflexe předpokládá přiznání vlivu individuálního světového názoru historika (komplexu názorů a postojů formovaných výchovou, vzděláním, vzpomínkami, generační příslušností a podobně) na jeho vědeckou činnost. Autor studie nabízí dvě možné a vzájemně se doplňující cesty k poznání historikova světového názoru: jednak prostřednictvím vlastních svědectví a prohlášení z jeho osobněji laděných textů a egodokumentů (eseje, rozhovory, vzpomínky, příspěvky na sociálních sítích), jednak analýzou jeho vědeckých textů (časopiseckých studií, knižních monografií, recenzí). Oba přístupy autor dokumentuje na konkrétních příkladech z produkce historiků a historiček českých soudobých dějin. V závěru studie pak nastiňuje cíle a smysl zkoumání historikova světového názoru.The aim of this study is to present the opportunities for research into the worldview of historians, especially historians focused on contemporary history, where it can be assumed that their set of values may influence their interpretation of the rela-tively recent past. The author first defines the notion of worldview and justifies the analytical use of this concept in historiographical texts. He also considers the relationship between memory, history and historiography in the given context. The author states that not many Czech historians have so far reflected on the relationship between (individual and collective) memory and the work of the historian, especially with regard to his or her position in contemporary society, which is often reduced to the role of an objective “discoverer of historical truth”. Such (self)reflection presupposes the acknowledgement of the influence of the historian’s individual worldview (a complex of opinions and attitudes shaped by upbringing, education, memories, generational affiliation and so on) on his or her scholarly activity. The author of the study offers two possible and complementary ways to learn about the historian’s worldview: first, through his or her own testimonies and statements from more personal texts and ego-documents (essays, interviews, memoirs or social me-dia posts), and second, through the analysis of his or her scholarly texts (journal studies, monographs and book reviews). The author demonstrates both approaches with concrete examples of works by historians of Czech contemporary history and concludes by outlining the aims and purpose of examining the historian’s worldview. © 2022, Institute of Contemporary History of the Czech Academy of Sciences. All rights reserved
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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