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Climatic regulation of leaf and cambial phenology in Quercus pubescens : their interlinkage and impact on xylem and phloem conduits
Jožica Gričar, Jernej Jevšenak, Polona Hafner, Peter Prislan, Mitja Ferlan, Martina Lavrič, Dominik Vodnik, Klemen Eler, 2022

Povzetek: Increased frequency and severity of stressful events affects the growth patterns and functioning of trees which adjust their phenology to given conditions. Here, we analysed environmental effects (temperature, precipitation, VPD and SWC) on the timing of leaf phenology, seasonal stem radial growth patterns, and xylem and phloem anatomy of Quercus pubescens in the sub-Mediterranean in the period 2014%2019, when various adverse weather events occurred, i.e. spring drought in 2015, summer fire in 2016 and summer drought in 2017. Results showed that the timings of leaf and cambium phenology do not occur simultaneously in Q. pubescens, reflecting different environmental and internal constraints. Although year-to-year variability in the timings of leaf and cambial phenology exists, their chronological sequence is fairly fixed. Different effects of weather conditions on different stages of leaf development in spring were observed. Common climatic drivers (i.e., negative effect of hot and dry summers and a positive effect of increasing moisture availability in winter and summer) were found to affect the widths of xylem and phloem increments with more pronounced effect on late formed parts. A legacy effect of the timing of leaf and cambial phenology of the previous growing season on the timing of phenology of the following spring was confirmed. Rarely available phloem data permitted a comprehensive insight into the interlinkage of the timing of cambium and leaf phenology and adjustment strategies of vascular tissues in Mediterranean pubescent oak to various environmental constraints, including frequent extreme events (drought, fire). Our results suggest that predicted changes in autumn/winter and spring climatic conditions for this area could affect the timings of leaf and stem cambial phenology of Q. pubescens in the coming years, which would affect stem xylem and phloem structure and hydraulic properties, and ultimately its performance.
Ključne besede: pubescent oak, leaf development, radial growth, initial earlywood vessel, sieve tube, anatomy, cambial cell production, extreme weather events
DiRROS - Objavljeno: 06.09.2021; Ogledov: 48; Prenosov: 8
.pdf Celotno besedilo (7,00 MB)

The aging muscle in experimental bed rest : ǂa ǂsystematic review and meta-analysis
Filippo Giorgio Di Girolamo, Nicola Fiotti, Zoran Milanović, Roberta Situlin, Filippo Mearelli, Pierandrea Vinci, Boštjan Šimunič, Rado Pišot, Marco Vincenzo Narici, Gianni Biolo, 2021

Povzetek: Background: Maintaining skeletal muscle mass and function in aging is crucial for preserving the quality of life and health. An experimental bed rest (BR) protocol is a suitable model to explore muscle decline on aging during inactivity. Objective: The purpose of this systematic review and meta-analysis was, therefore, to carry out an up-to-date evaluation of bed rest, with a specific focus on the magnitude of effects on muscle mass, strength, power, and functional capacity changes as well as the mechanisms, molecules, and pathways involved in muscle decay. Design: This was a systematic review and meta-analysis study. Data sources: We used PubMed, Medline; Web of Science, Google Scholar, and the Cochrane library, all of which were searched prior to April 23, 2020. A manual search was performed to cover bed rest experimental protocols using the following key terms, either singly or in combination: %Elderly Bed rest,% %Older Bed rest,% %Old Bed rest,% %Aging Bed rest,% %Aging Bed rest,% %Bed-rest,% and %Bedrest%. Eligibility criteria for selecting studies: The inclusion criteria were divided into four sections: type of study, participants, interventions, and outcome measures. The primary outcome measures were: body mass index, fat mass, fat-free mass, leg lean mass, cross-sectional area, knee extension power, cytokine pattern, IGF signaling biomarkers, FOXO signaling biomarkers, mitochondrial modulation biomarkers, and muscle protein kinetics biomarkers. Results: A total of 25 studies were included in the qualitative synthesis, while 17 of them were included in the meta-analysis. In total, 118 healthy elderly volunteers underwent 5-, 7-, 10-, or 14-days of BR and provided a brief sketch on the possible mechanisms involved. In the very early phase of BR, important changes occurred in the skeletal muscle, with significant loss of performance associated with a lesser grade reduction of the total body and muscle mass. Meta-analysis of the effect of bed rest on total body mass was determined to be small but statistically significant (ES = %0.45, 95% CI: %0.72 to %0.19, P < 0.001). Moderate, statistically significant effects were observed for total lean body mass (ES = %0.67, 95% CI: %0.95 to %0.40, P < 0.001) after bed rest intervention. Overall, total lean body mass was decreased by 1.5 kg, while there was no relationship between bed rest duration and outcomes (Z = 0.423, p = 672). The meta-analyzed effect showed that bed rest produced large, statistically significant, effects (ES = %1.06, 95% CI: %1.37 to %0.75, P < 0.001) in terms of the knee extension power. Knee extension power was decreased by 14.65 N/s. In contrast, to other measures, meta-regression showed a significant relationship between bed rest duration and knee extension power (Z = 4.219, p < 0.001). Moderate, statistically significant, effects were observed after bed rest intervention for leg muscle mass in both old (ES = %0.68, 95% CI: %0.96 to %0.40, P < 0.001) and young (ES = %0.51, 95% CI: %0.80 to %0.22, P < 0.001) adults. However, the magnitude of change was higher in older (MD = %0.86 kg) compared to younger (MD = %0.24 kg) adults. Conclusion: Experimental BR is a suitable model to explore the detrimental effects of inactivity in young adults, old adults, and hospitalized people. Changes in muscle mass and function are the two most investigated variables, and they allow for a consistent trend in the BR-induced changes. Mechanisms underlying the greater loss of muscle mass and function in aging, following inactivity, need to be thoroughly investigated.
Ključne besede: bed rest, aging, muscles, muscle physiopathology, muscle function
DiRROS - Objavljeno: 26.08.2021; Ogledov: 70; Prenosov: 41
.pdf Celotno besedilo (1,32 MB)

Empirical approach for modelling tree phenology in mixed forests using remote sensing
Koffi Dodji Noumonvi, Gal Oblišar, Ana Žust, Urša Vilhar, 2021

Povzetek: : Phenological events are good indicators of the effects of climate change, since phenological phases are sensitive to changes in environmental conditions. Although several national phenological networks monitor the phenology of different plant species, direct observations can only be conducted on individual trees, which cannot be easily extended over large and continuous areas. Remote sensing has often been applied to model phenology for large areas, focusing mostly on pure forests in which it is relatively easier to match vegetation indices with ground observations. In mixed forests, phenology modelling from remote sensing is often limited to land surface phenology, which consists of an overall phenology of all tree species present in a pixel. The potential of remote sensing for modelling the phenology of individual tree species in mixed forests remains underexplored. In this study, we applied the seasonal midpoint (SM) method with MODIS GPP to model the start of season (SOS) and the end of season (EOS) of six different tree species in Slovenian mixed forests. First, substitute locations were identified for each combination of observation station and plant species based on similar environmental conditions (aspect, slope, and altitude) and tree species of interest, and used to retrieve the remote sensing information used in the SM method after fitting the best of a Gaussian and two double logistic functions to each year of GPP time series. Then, the best thresholds were identified for SOS and EOS, and the results were validated using cross-validation. The results show clearly that the usual threshold of 0.5 is not best in most cases, especially for estimating the EOS. Despite the difficulty in modelling the phenology of different tree species in a mixed forest using remote sensing, it was possible to estimate SOS and EOS with moderate errors as low as <8 days (Fagus sylvatica and Tilia sp.) and <10 days (Fagus sylvatica and Populus tremula), respectively.
Ključne besede: phenology modelling, start of season, end of season, remote sensing, MODIS GPP, vegetation indices, threshold methods
DiRROS - Objavljeno: 23.08.2021; Ogledov: 66; Prenosov: 40
.pdf Celotno besedilo (2,63 MB)

Aktiviranje gospodarjenja v zasebnih gozdovih s poslovnim sodelovanjem med zasebnimi lastniki gozdov in ponudniki gozdarskih storitev: študij primera revir Vodice
Nina Iveta, Špela Pezdevšek Malovrh, 2021

Povzetek: V prispevku smo preverjali možnost aktiviranja gospodarjenja v zasebnih gozdovih s pomočjo poslovnega povezovanja znotraj poslovnih modelov 'zakup gozda' in 'upravljanje gozda' med zasebnimi lastniki gozdov in ponudniki gozdarskih storitev. S pomočjo anketiranja zasebnih lastnikov gozda (n = 205) in ponudnikov gozdarskih storitev (n = 14) smo ugotovili, da je pripra%vljenost za poslovno sodelovanje v obeh predlaganih poslovnih modelih večja pri ponudnikih gozdarskih storitev, kot pa je pri zasebnih lastnikih gozdov. Nadalje smo ugotovili, da je poslovno sodelovanje znotraj predlaganih poslovnih modelov uresni%čljivo, saj je stopnja sodelovanja zasebnih lastnikov gozdov s ponudniki gozdarskih storitev v 10-letnem obdobju zadovoljiva, hkrati pa so se predlagani pogoji, ki urejajo poslovno razmerje in temeljne obveznosti pogodbenih strank, izkazali za primerne za oba poslovna partnerja. Za začetek vzpostavitve poslovnega sodelovanja je treba najprej poskrbeti za promocijo poslovnega povezovanja in sodelovanja na lokalnem nivoju ter vzpostaviti poslovne odnose med potencialnimi partnerji.
Ključne besede: zasebni gozdovi, gospodarjenje, poslovno sodelovanje zasebnih lastnikov gozdov, ponudniki gozdarskih storitev, poslovni modeli, zakup gozda, upravljanje gozda, zasebni lastniki gozdov
DiRROS - Objavljeno: 17.08.2021; Ogledov: 146; Prenosov: 80
.pdf Celotno besedilo (821,00 KB)

Značilnosti opravljanja sečnje in spravila v zasebnih gozdovih v Sloveniji
Matevž Triplat, Nike Krajnc, Darja Stare, Špela Ščap, 2021

Povzetek: V raziskavi, opravljeni leta 2019, je bilo zajetih 544 naključno izbranih gospodinjstev, ki imajo v lasti gozd. Več kot polovica anketi%ranih ima v lasti gozdno posest, veliko od 1 do 4,99 ha. Za 62 % anketiranih je glavni namen gospodarjenja z gozdom uporaba lesa za lastne potrebe. V obdobju 2015%2019 je sečnjo in spravilo opravljalo 71 % anketiranih, ki so v tem času skupaj posekali nekaj manj kot 50.000 m3 lesa (24 m3 /ha ali 141 m3 na gospodinjstvo). Intenziteta sečnje je bila najvišja pri zasebnih lastnikih z malimi gozdnimi posestmi (do 0,99 ha), in sicer v povprečju 41,4 m3 /ha. Analiza je pokazala, da obstajajo statistično značilne razlike med velikostjo gozdne posesti in intenziteto sečnje. V anketi je bilo ugotovljeno, da so za 41 % sečnje in spravila poskrbeli poklicni izvajalci del. Z raziskavo smo potrdili značilen vpliv velikosti zasebne gozdne posesti na način izvedbe sečnje in spravila. Rezultati so pokazali, da je največji delež zasebnih lastnikov, ki vsa dela opravijo s pomočjo najetih izvajalcev, v velikostnem razredu gozdne posesti od 5 do 9,99 ha. Z raziskavo nismo potrdili statistično značilnih razlik v intenziteti sečnje med spoloma zasebnih lastnikov gozdov
Ključne besede: zasebni lastniki, anketa, intenziteta sečnje, struktura lastnikov, gozdna posest, sečnja, spravilo, zasebni gozdovi
DiRROS - Objavljeno: 17.08.2021; Ogledov: 131; Prenosov: 69
.pdf Celotno besedilo (953,03 KB)

The influence of land use on the spatial distribution and intensity of heat islands in Slovenia
Anica Simčič, Petra Pečan, Mojca Nastran, Milan Kobal, 2021

Povzetek: Heat islands (HI) are a common anthropogenic phenomenon and are defined as artificial surfaces (urban areas) that have a higher average temperature than their surroundings (rural areas). The aim of this work was to determine the influence of land use on the spatial distribution and intensity (HIi ) of HI in Slovenia. The MODIS Land Surface Temperature (LST) and Corine Land Cover (CLC) databases were used to perform the analysis. Within the identified HI, two HI levels were determined based on temperature difference. The results revealed a statistically significant negative correlation between HIi and both forest co%ver and forest fragmentation (forest edge density and ratio of mean forest patch size to HI size). Artificial surface was positively correlated with HIi . The results contribute to the understanding of the spatial distribution of HI and HIi and provide informati%on for spatial planning and policy-making to reduce the negative impact of HI.
Ključne besede: heat island, forest cover, artificial surface, forest fragmentation
DiRROS - Objavljeno: 17.08.2021; Ogledov: 251; Prenosov: 100
.pdf Celotno besedilo (1011,73 KB)

Modeliranje višinske in debelinske rasti dominantnih dreves ter ocenjevanje indeksov produkcijske sposobnosti gozdnih rastišč
Andrej Bončina, Vasilije Trifković, Živa Bončina, 2021

Povzetek: Modeli višinskega in debelinskega priraščanja dreves so pomembni za upravljanje gozdov, saj so podlaga za določanje režima redčenj, ciljnih premerov drevesnih vrst in optimalnega razmerja razvojnih faz ter ocenjevanje produkcijske sposobnosti goz%dnih rastišč. S podatki s stalnih vzorčnih ploskev smo za dva gozdna tipa (gradnovo bukovje na izpranih tleh in predalpsko jelovo bukovje) modelirali višinsko rast dominantnih bukev in smrek glede na njihov premer. Za obe vrsti smo ocenili rastiščni produkcijski indeks (SPI), ki je dominanta višina drevja pri prsnem premeru 45 cm. Na podlagi debelinskega priraščanja do%minantnih dreves smo ocenili prehodne dobe in povprečno starost dreves glede na njihovo debelino. To so bili vhodni podatki za določitev regresijskega modela višine dominantnih dreves glede na njihovo starost. SPI je za smreko v primerjavi z bukvijo pričakovano višji, pri bukvi je vrednost SPI višja na rastišču gradnovega bukovja na izpranih tleh (28,7 m proti 27,9 m), pri smreki pa na rastišču predalpskega jelovega bukovja (31,3 m proti 29,7 m). Vrednosti rastiščnih indeksov (SI; dominantna višina drevja pri starosti 100 let) smreke na rastiščih gradnovega bukovja in predalpskega jelovega bukovja so 33,4 in 32,0, bukve pa 29,0 in 27,0. Z opisanim postopkom smo za izbrana gozdna rastiščna tipa določili indekse produkcijske sposobnosti gozdnih smreke in bukve (SI in SPI); uporabnost postopka je treba preveriti še za druge drevesne vrste in gozdne rastiščne tipe.
Ključne besede: dominantna drevesa, višinska rast, debelinska rast, rastiščni indeks, rastiščni produkcijski indeks, Fagus sylvatica, Picea abies
DiRROS - Objavljeno: 17.08.2021; Ogledov: 202; Prenosov: 96
.pdf Celotno besedilo (840,99 KB)

Vpliv podnebnih sprememb na dinamiko glivnega razkroja lesa v Sloveniji
Miha Humar, Boštjan Lesar, Davor Kržišnik, 2021

Povzetek: Intenziteta glivnega razkroja je v največji meri odvisna od vrste lesa, temperature in padavinskih dogodkov. Če želimo oceniti življenjsko dobo in intervale vzdrževanja lesenih objektov, moramo oceniti, kako se bo v določenem okolju les obnašal. V ta namen so nam na voljo raznoliki modeli. V praksi se največ uporablja pristop, ki ga je razvil Theodore Scheffer. Scheffer je predlagal klimatski indeks (Schefferjev klimatski indeks - SCI), ki temelji na številu padavinskih dni in povprečni mesečni temperaturi. Na podlagi teh klimatskih podatkov smo izračunali Schefferjev klimatski indeks za izbrane lokacije v Sloveniji. Rezultati analize klimatskih razmer kažejo, da je Schefferjev klimatski indeks v večini analiziranih krajev v Sloveniji višji, kot je bil pred desetletji. Intenziteta razkroja se je povečala v vseh analiziranih krajih z izjemo Portoroža. Največje zvišanje Schefferjevega klimatskega indeksa smo zaznali v Ratečah.
Ključne besede: les, Schefferjev klimatski indeks, razkroj, podnebne spremembe, temperatura, padavinski dogodki
DiRROS - Objavljeno: 17.08.2021; Ogledov: 118; Prenosov: 65
.pdf Celotno besedilo (1004,81 KB)

Treatment outcome clustering patterns correspond to discrete asthma phenotypes in children
Ivana Banić, Mario Lovrić, Gerald Cuder, Roman Kern, Matija Rijavec, Peter Korošec, Mirjana Kljajić-Turkalj, 2021

Povzetek: Despite widely and regularly used therapy asthma in children is not fully controlled. Recognizing the complexity of asthma phenotypes and endotypes imposed the concept of precision medicine in asthma treatment. By applying machine learning algorithms assessed with respect to their accuracy in predicting treatment outcome, we have successfully identified 4 distinct clusters in a pediatric asthma cohort with specific treatment outcome patterns according to changes in lung function (FEV1 and MEF50), airway inflammation (FENO) and disease control likely affected by discrete phenotypes at initial disease presentation, differing in the type and level of inflammation, age of onset, comorbidities, certain genetic and other physiologic traits. The smallest and the largest of the 4 clusters- 1 (N = 58) and 3 (N = 138) had better treatment outcomes compared to clusters 2 and 4 and were characterized by more prominent atopic markers and a predominant allelic (A allele) effect for rs37973 in the GLCCI1 gene previously associated with positive treatment outcomes in asthmatics. These patients also had a relatively later onset of disease (6 + yrs). Clusters 2 (N = 87) and 4 (N = 64) had poorer treatment success, but varied in the type of inflammation (predominantly neutrophilic for cluster 4 and likely mixed-type for cluster 2), comorbidities (obesity for cluster 2), level of systemic inflammation (highest hsCRP for cluster 2) and platelet count (lowest for cluster 4). The results of this study emphasize the issues in asthma management due to the overgeneralized approach to the disease, not taking into account specific disease phenotypes.
Ključne besede: asthma, allergy and immunology, pediatrics, machine learning, treatment outcome, phenotypes, childhood asthma, clustering
DiRROS - Objavljeno: 16.08.2021; Ogledov: 72; Prenosov: 46
.pdf Celotno besedilo (1,32 MB)

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