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1.
Identification and content of astaxanthin and its esters from microalgae Haematococcus pluvialis by HPLC-DAD and LC-QTOF-MS after extraction with various solvents
Biljana Todorović, Jaša Veno Grujić, Andreja Urbanek Krajnc, Roman Kranvogl, Jana Ambrožič-Dolinšek, 2021, original scientific article

Abstract: Haematococcus pluvialis, a unicellular green microalga that produces a secondary metabolite under stress conditions, bears one of the most potent antioxidants, namely xanthophyll astaxanthin. The aim of our study was to determine the content of astaxanthin and its esterified forms using three different solvents—methyl tert-butyl ether (MTBE), hexane isopropanol (HEX -IPA) and acetone (ACE)—and to identify them by using high performance liquid chromatography coupled with diode array detection and the quadrupole time-of-flight mass spectrometry (HPLC-DAD and LC-QTOF-MS) technique. We identified eleven astaxanthin monoesters, which accounted for 78.8% of the total astaxanthin pool, six astaxanthin diesters (20.5% of total), while free astaxanthin represented the smallest fraction (0.7%). Astaxanthin monoesters (C16:2, C16:1, C16:0), which were the major bioactive compounds in the H. pluvialis samples studied, ranged from 10.2 to 11.8 mg g−1 DW. Astaxanthin diesters (C18:4/C18:3, C18:1/C18:3) were detected in the range between 2.3 and 2.6 mg g−1 DW. All three solvents were found to be effective for extraction, but MTBE and hexane-isopropanol extracted the greatest amount of free bioactive astaxanthin. Furthermore, MTBE extracted more low-chain astaxanthin monoesters (C16), and hexane-isopropanol extracted more long-chain monoesters (C18 and above) and more diesters. We can conclude that MTBE is the solvent of choice for the extraction of monoesters and hexane-isopropanol for diesters.
Keywords: astaxanthin diesters, astaxanthin monoesters, carotenoids, Hematococcus pluvialis, astaxanthin diesters, solvent extraction
Published in DKUM: 22.11.2024; Views: 0; Downloads: 6
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2.
A spatial decision support system for traffic accident prevention in different weather conditions
Danijel Ivajnšič, David Pintarič, Jaša Veno Grujić, Igor Žiberna, 2021, original scientific article

Abstract: Natural conditions play an important role as determinants and cocreators of the spatiotemporal road traffic accident Hot Spot footprint; however, none of the modern commercial, or open-source, navigation systems currently provides it for the driver. Our findings, based on a spatiotemporal database recording 11 years of traffic accidents in Slovenia, proved that different weather conditions yield distinct spatial patterns of dangerous road segments. All potentially dangerous road segments were identified and incorporated into a mobile spatial decision support system (SLOCrashInfo), which raises awareness among drivers who are entering or leaving the predefined danger zones on the street network. It is expected that such systems could potentially increase road traffic safety in the future.
Keywords: GIS, mobile application, spatial databases, spatial patterns, traffic safety
Published in DKUM: 20.08.2024; Views: 63; Downloads: 11
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3.
The Lyme borreliosis spatial footprint in the 21st century : a key study of Slovenia
Daša Donša, Jaša Veno Grujić, Nataša Pipenbaher, Danijel Ivajnšič, 2021, original scientific article

Abstract: After mosquitoes, ticks are the most important vectors of infectious diseases. They play an important role in public health. In recent decades, we discovered new tick-borne diseases; additionally, those that are already known are spreading to new areas because of climate change. Slovenia is an endemic region for Lyme borreliosis and one of the countries with the highest incidence of this disease on a global scale. Thus, the spatial pattern of Slovenian Lyme borreliosis prevalence was modelled with 246 indicators and transformed into 24 uncorrelated predictor variables that were applied in geographically weighted regression and regression tree algorithms. The projected potential shifts in Lyme borreliosis foci by 2050 and 2070 were calculated according to the RCP8.5 climate scenario. These results were further applied to developing a Slovenian Lyme borreliosis infection risk map, which could be used as a preventive decision support system.
Keywords: CART, climate change, MGWR, Lyme disease, infection risk, spatial modelling
Published in DKUM: 12.08.2024; Views: 69; Downloads: 10
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4.
Modeliranje podnebne ustreznosti za gojenje oljk (Olea europaea) na vzhodnem Jadranu (Slovenija, Hrvaška)
Iztok Lorenčič, Mitja Kaligarič, Daša Donša, Jaša Veno Grujić, Danijel Ivajnšič, 2022, independent scientific component part or a chapter in a monograph

Abstract: Pridelava oljk je ranljiv kmetijski sistem, primeren za študije vpliva podnebnih sprememb zaradi dolge življenjske dobe oljčnega drevesa, njegove občutljivosti na sušo in visoke temperature ter vse večje vloge oljčnih nasadov v gospodarstvu sredozemskih območij. S pomočjo prostorske analize smo ugotavljali, kakšna je podnebna ustreznost za gojenje oljk v Sloveniji in na Hrvaškem. Ocenjujemo vpliv bioklimatskih spremenljivk na razširjenost oljčnikov na tem območju, vrednotimo prihodnje podnebne pogoje za gojenje oljk, zaznavamo variabilnost modelnih podnebnih napovedi na primeru oljčnikov in identificiramo prihodnja ustrezna in neustrezna območja za gojenje oljk v Sloveniji in na Hrvaškem. Obravnavana podnebna scenarija RCP4.5 in RCP8.5, v primeru oljke, kažeta različen razvoj ustreznih površin za gojenje na raziskovanem območju. Model Mahalanobisove tipičnosti (MT) napoveduje krčenje ustreznih pogojev v severnem predelu območja. Model Podnebne ustreznosti pridelka (CCS) pa kaže največje razlike v podnebni ustreznosti za gojenje oljk na območju Dalmacije, kjer bo lahko v prihodnosti več ustreznih površin tudi v notranjosti celine. Dolgoročne podnebne napovedi so lahko na lokalnem nivoju dokaj nezanesljive. Za natančnejše napovedi ustreznih pogojev za gojenje oljke bi bile potrebne bolj poglobljene analize na regionalni ravni. Prav gotovo bo oljkam v prihodnosti ustrezalo toplejše ozračje, vendar je problematika večplastna.
Keywords: emisijski scenariji, modeli razširjenosti vrst, podnebna ustreznost, prostorske analize, bioklimatske spremenljivke
Published in DKUM: 03.06.2024; Views: 151; Downloads: 9
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5.
Vpliv urbanih zelenih površin na pojav mestnega toplotnega otoka
Nataša Pipenbaher, Danijel Ivajnšič, Daša Donša, Jaša Veno Grujić, Sonja Škornik, 2022, independent scientific component part or a chapter in a monograph

Abstract: Urbane zelene površine so izpostavljene vzajemnemu vplivu pojava mestnega toplotnega otoka (MTO) in višjim temperaturam zraka zaradi podnebnih sprememb, kar spreminja rastne parametre rastlin, po drugi strani pa lahko delujejo kot blažilec toplotnega stresa zaradi povečanega toka latentne toplote (posledica evapotranspiracije). Da bi ocenili jakost hladilnega učinka zelenih površin v urbanih sistemih (Maribor, Murska Sobota, Ljutomer) smo v devetih zelenih površinah (trije mestni gozdovi in šest mestnih parkov) popisali lesne vrste na 94 popisnih ploskvah. Zbrali smo podatke o številu/gostoti osebkov lesnih vrst, povprečni vrednosti morfološko funkcionalnih potez za vsebnost suhe snovi v listih (CWM_LDMC) in specifično listno površino (CWM_SLA). Izračunali smo intenzivnost hlajenja, obseg hlajenja in stopnjo hlajenja v in izven popisnih ploskev. Mestni gozdovi imajo večji hladilni učinek od mestnih parkov. Sicer pa pravilo večja zelena površina – večji hladilni učinek ne velja povsod. Analiza dejavnikov vpliva hladilnega učinka urbanih zelenih površin je razkrila značilen vpliv: (1) velikosti zelene površine, (2) števila/gostote lesnih vrst in vezanih povprečnih vrednosti morfološko funkcionalnih potez (predvsem CWM_SLA), (3) tipa zelene površine in pokritosti tal neposredne okolice. Dobro umeščene zelene površine lahko razčlenijo sicer homogeno temperaturno polje nad pozidanimi površinami mest, še zlasti ob nastopu vročinskih valov.
Keywords: podnebne spremembe, hladilni učinek, lesne vrste, urbani sistemi, lokalne podnebne cone
Published in DKUM: 03.06.2024; Views: 167; Downloads: 13
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6.
Diversity and content of carotenoids and other pigments in the transition from the green to the red stage of Haematococcus pluvialis microalgae identified by HPLC-DAD and LC-QTOF-MS
Jaša Veno Grujić, Biljana Todorović, Roman Kranvogl, Terezija Ciringer, Jana Ambrožič-Dolinšek, 2022, original scientific article

Abstract: H. pluvialis is a unicellular freshwater alga containing many bioactive compounds, especially carotenoids, which are the strongest antioxidants among the pigments. This study evaluates the composition and content of carotenoids and other pigments in both stages of algae life cycle, especially in the green vegetative stage, less studied in comparison to the red stage. To determine the composition and content of carotenoids, a combination of HPLC-DAD and LC-QTOF-MS was used. The content of carotenoids in the green vegetative stage was significantly lower than in the red vegetative stage. In the green vegetative stage, 16 different carotenoids and other pigments were identified. Among the total 8.86 mg g−1 DW of pigments, 5.24 mg g−1 DW or 59% of them were chlorophyll a with its derivatives, and 3.62 mg g−1 DW or 41% of them were free carotenoids. After the transition from the green to the red stage, the carotenoid composition was replaced by secondary carotenoids, astaxanthin and its esters, which predominated in the whole carotenoid composition. In addition to free astaxanthin, 12 astaxanthin monoesters, 6 diesters and 13 other carotenoids were determined. The majority of 37.86 mg g−1 DW pigments were monoesters. They represented 82% of all pigments, and their content was about 5 times higher than both, diesters (5.91 mg g−1 DW or 12% of all) and free carotenoids (2.4 mg g−1 DW or 6% of all). The results of the study contribute to the data on the overall pigment composition and content of H. pluvialis algae and provide the basis for further improvement of cultivation of the H. pluvialis algae.
Keywords: antioxidants, astaxanthin, chlorophylls, bioactive compounds, algae, Haematococcus, life cycle, pigment composition, secondary carotenoids
Published in DKUM: 21.05.2024; Views: 172; Downloads: 13
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7.
Evaluating seagrass meadow dynamics by integrating field-based and remote sensing techniques
Danijel Ivajnšič, Martina Orlando-Bonaca, Daša Donša, Jaša Veno Grujić, Domen Trkov, Borut Mavrič, Lovrenc Lipej, 2022, original scientific article

Abstract: Marine phanerogams are considered biological sentinels or indicators since any modification in seagrass meadow distribution and coverage signals negative changes in the marine environment. In recent decades, seagrass meadows have undergone global losses at accelerating rates, and almost one-third of their coverage has disappeared globally. This study focused on the dynamics of seagrass meadows in the northern Adriatic Sea, which is one of the most anthropogenically affected areas in the Mediterranean Sea. Seagrass distribution data and remote sensing products were utilized to identify the stable and dynamic parts of the seagrass ecosystem. Different seagrass species could not be distinguished with the Sentinel-2 (BOA) satellite image. However, results revealed a generally stable seagrass meadow (283.5 Ha) but, on the other hand, a stochastic behavior in seagrass meadow retraction (90.8 Ha) linked to local environmental processes associated with anthropogenic activities or climate change. If systemized, this proposed approach to monitoring seagrass meadow dynamics could be developed as a spatial decision support system for the entire Mediterranean basin. Such a tool could serve as a key element for decision makers in marine protected areas and would potentially support more effective conservation and management actions in these highly productive and important environments.
Keywords: Adriatic Sea, seagrass meadow, change analysis, Cimodocea nodosa, image classifiers, Sentinel-2, marine biology, hydrobiology
Published in DKUM: 17.05.2024; Views: 152; Downloads: 13
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8.
Pomen izkustvenega učenja predšolskih otrok za spoznavanje gozda in živali v njem : diplomsko delo
Jerneja Iršič, 2022, undergraduate thesis

Abstract: Diplomsko delo Pomen izkustvenega učenja predšolskih otrok za spoznavanje gozda in živali v njem prinaša rezultate pridobljene na podlagi izkustvenega učenja. S skupino 24 otrok smo v gozdu raziskovali drevesna debla in krošnje, ter v zgornjih plasteh prsti iskali drobne živali. Otroci v starosti 5-6 let so se tekom večdnevnega raziskovanja gozda naučili veliko o izbranih drevesnih in živalskih vrstah.. Njihovo znanje o drevesnih vrstah in živalih smo preverili pred in po 8 dnevnem raziskovanju gozda. Otroke smo usmerili v opazovanje, raziskovanje in prepoznavanje treh drevesnih vrst (navadna smreka, hrast dob, navadna bukev) in petih vrst drobnih živali tal (navadna strigalica, stenica, ozka striga, železna kačica, navadni prašiček). Pri drevesnih vrstah so otroci raziskovali liste, plodove in skorjo posameznih dreves. Pri živalih pa so raziskovali gozdna tla in iskali njihova bivališča ter opazovali njihovo telesno zgradbo. Rezultati raziskave nam kažejo, da je pri otrocih napredek v znanju. Še posebej se napredek opazi pri otroku (OC1), ki po mnenju vzgojiteljice ni bil motiviran za dejavnosti s področja narave in pred raziskovanjem v gozdu ni prepoznal nobenega drevesnega dela katerekoli drevesne vrste. Po raziskovanju je ta isti otrok prepoznal kar 6 od 9 drevesnih delov.
Keywords: izkustveno učenje, drobne živali tal, drevesa, narava, otroci
Published in DKUM: 26.10.2022; Views: 908; Downloads: 122
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9.
The impact of climate change on urban thermal environment dynamics
Igor Žiberna, Nataša Pipenbaher, Daša Donša, Sonja Škornik, Mitja Kaligarič, Lučka Kajfež-Bogataj, Zalika Črepinšek, Jaša Veno Grujić, Danijel Ivajnšič, 2021, original scientific article

Abstract: The human population is increasing. The ongoing urbanization process, in conjunction with climate change, is causing larger environmental footprints. Consequently, quality of life in urban systems worldwide is under immense pressure. Here, the seasonal characteristics of Maribor's urban thermal environment were studied from the perspectives of surface urban heat island (SUHI) and urban heat island (UHI) A remote sensing thermal imagery time series and in-situ measurements (stationary and mobile) were combined with select geospatial predictor variables to model this atmospheric phenomenon in its most intensive season (summer). Finally, CMIP6 climate change scenarios and models were considered, to predict future UHI intensity. Results indicate that Maribor's UHI intensity maximum shifted from winter to spring and summer. The implemented generalized additive model (GAM) underestimates UHI intensity in some built-up parts of the study area and overestimates UHI intensity in green vegetated areas. However, by the end of the century, UHI magnitude could increase by more than 60% in the southern industrial part of the city. Such studies are of particular concern, in regards to the increasing frequency of heat waves due to climate change, which further increases the (already present) heat stress in cities across the globe.
Keywords: GAM, CMIP6, UHI, urban heat island, urbanisation, SUHI, summer heat stress
Published in DKUM: 02.09.2022; Views: 794; Downloads: 26
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10.
Primeri prostorskih analiz vplivov podnebnih sprememb : monografija v okviru projekta Preprečevanje toplotnega stresa v urbanih sistemih v luči podnebnih sprememb (ARRS J7-1822)
2022, scientific monograph

Abstract: V obdobju digitalne preobrazbe družbe na pomenu pridobivajo tudi informacijske tehnologije. Sem sodijo geografski informacijski sistemi, ki povezujejo lokacijske podatke z vsemi vrstami opisnih informacij, in s tem zagotavljajo osnovo za kartiranje in prostorsko analizo. Slednja se dandanes uporablja tako v znanosti kot v industriji. S pomočjo tovrstne analize lažje razumemo pretekle in sedanje prostorske vzorce, ki so posledica interakcije naravnih in družbenih razmer. Na podlagi zaznanih trendov lahko nato celo ocenjujemo, kakšen bo nadaljnji prostorski razvoj. Prav zmožnost objektivnega napovedovanja je ena izmed ključnih lastnosti, ki dodatno poveča uporabnost prostorskih analiz z vidika vrednotenja posledic podnebne ali bolje okoljske krize. Prav to dejstvo je povod za nastanek monografije z naslovom Primeri prostorskih analiz vplivov podnebnih sprememb. Monografija je razdeljena na tri poglavja. Prvo obravnava urbana okolja in se dotakne problematike vse pogostejšega toplotnega stresa kot posledice pojava mestnega toplotnega otoka (MTO) in toplejše atmosfere zaradi (antropogeno pospešenih) podnebnih sprememb. Drugo poglavje monografije obravnava vplive podnebnih sprememb na izbrane habitate kulturne krajine, bodisi v intenzivni ali ekstenzivni kmetijski rabi. V tretjem poglavju pa se vsebinsko premaknemo iz kopenskih na obmorska in morska okolja.
Keywords: prostorske analize, podnebne spremembe, geografski infomracijski sistemi, prostorski vzorci, okoljska kriza
Published in DKUM: 26.08.2022; Views: 689; Downloads: 39
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