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Abstract: Prispevek nas seznanja z osnovnimi informacijami o trajnostnem razvoju slovenskih gozdov med letoma 2000 in 2018. Stanje in razvoj slovenskih gozdov z vidika trajnosti smo preverili z nizom spremenljivk in kazalnikov trajnostnega gospodarjenja z gozdovi: površina gozdov, temeljnica, lesna zaloga, indeks sestojne gostote, starostna struktura/porazdelitev prsnih premerov, ravnotežje razvojnih faz, optimalna lesna zaloga, prirastek, posek, različnost drevesnih vrst, mešanost sestojev, pomlajevanje, naravnost in odmrla drevnina. Ocenili smo tudi ustreznosti sistematične mreže 4 x 4 km, ki se je uporabljala za velikoprostorsko inventarizacijo. Vse vzorčne ocene so bile izračunane za raven države, ekoregije in za gozdnogospodarska območja. Leta 2018 je gozdnatost dosegala 60 % in je bila višja kot l. 2012. Nasprotno se je lesna zaloga zmanjšala in je bila ocenjena na 329,6 m3 /ha. Površinski delež mlajših gozdov je znašal 29 %, starejših (sečno zrelih) 68 %, raznodobnih pa 3 %. Med drevesnimi vrstami je največji delež pripadal bukvi in smreki. Deleži drugih vrst niso presegli 10 %, posebej zaskrbljujoča je bila njihova vrast. Na osnovi primerjav z zaželenimi vrednostmi in vrednostmi kazalnikov v gozdovih držav članic procesa Forest Europe in nekaterimi izbranimi državami, je mogoče skleniti, da se razvoj slovenskih gozdov odmika od trajnostnega razvoja. Glede na razpoložljive podatke l. 2018 je tudi mogoče zaključiti, da velikoprostorska inventura MGGE l. 2018 s podatki ne zapolni vseh kazalnikov trajnostnega gospodarjenja z gozdovi.
Keywords: trajnostno gospodarjenje z gozdovi, kazalniki, časovna analiza, Slovenija
Published in DiRROS: 30.11.2023; Views: 939; Downloads: 306
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Abstract: Ekipa, ki se ukvarja z zagotavljanjem kakovosti na področju radiologije, posebno pa v mamografiji, mora dobro poznati uporabo senzitometra in denzitometra za spremljanje učinkovitosti razvijanja filmov. Prispevek uvaja bralca v osnove, ki so nujne za razumevanje programa zagotavljanja kakovosti in spremljanja parametrov učinkovitosti pri razvijanju mamografskih filmov.
Published in DiRROS: 30.11.2023; Views: 255; Downloads: 67
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Abstract: Mamografija je specialna radiografska preiskava katere namen je diagnostika karcinoma dojke. S tehnične plati mora zagotoviti dobro kontrastno ločljivost sprememb v mehkih tkivih, dobro prostorsko ločljivost mikrokalcinacij in kontur nasploh (robovi, spikule); to dosežemo kadar je radiografski šum dovoljnizek, da v sliki ne zabriše teh podrobnosti morfološke vsebine.
Published in DiRROS: 30.11.2023; Views: 280; Downloads: 87
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Abstract: Introduction: Herbaceous plant species constitute an essential element of the flora of European beech (Fagus sylvatica) forests. There is increasing evidence that rapidly changing climate is likely to modify the spatial distribution of plant species. However, we lack understanding of the impact that climate change might have on beech forest herbs across the European continent. We investigated the possible effects of predicted increasing rates of global warming and altered precipitation regimes on 71 forest herbs closely associated with beech forests, but with varying biogeographic and climatic niche attributes. Methods: By using a total of 394,502 occurrence records and an ensemble of species distribution models (SDMs), we quantified the potential current distribution and future (2061-2080) range shifts in climatic suitability (expressed as occurrence probability, OP) according to two climate change scenarios (moderate SSP2-4.5 and severe SSP5-8.5). Results: Overall, precipitation of the warmest quarter and temperature seasonality were the most influential predictors in shaping current distribution patterns. For SSP5-8.5 scenario, all studied species experienced significant reductions (52.9% on average) in the total size of highly suitable areas (OP >0.75). However, the magnitude and directions of changes in the climatic suitability were highly species-specific; few species might even increase OP in the future, particularly in case of SSP2-4.5 scenario. The SDMs revealed the most substantial decline of climatic suitability at the trailing edges in southern Europe. We found that climatic suitability is predicted to show unidirectional northward shift and to move toward higher elevations. The gain/loss ratio was generally higher for narrow-ranged species compared to widespread taxa. Discussion: Our findings are contextualized with regards to potential confounding factors (dispersal limitation, microclimatic buffering) that may mitigate or accelerate climate change impacts. Given the low long-distance migration ability, many beech forest herbs are unlikely to track the velocity with which macroclimatic isotherms are moving toward higher latitudes, making this species group particularly vulnerable to climate change.
Keywords: species distribution modelling, global warming, range shift, climatic niche, biogeography, Europe
Published in DiRROS: 29.11.2023; Views: 394; Downloads: 204
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Abstract: This paper presents results from an experimental assessment of glued-in rods in cross laminated timber (CLT). For the purposes of the study more than 60 pull-pull tests were performed, where the specimens varied in terms of bonded-in length (from 80 to 400 mm), rod diameter (16-24 mm) and rod-to-grain angle (parallel and perpendicular). Several different failure modes that are not common for other applications of glued-in rods (e.g., a failure between CLT layers) were obtained for the analysed CLT specimens. It was found that these failure mechanisms can substantially influence the obtained ultimate tension loads. At the end, the experimental results were compared with empirical and semi-empirical equations for estimating the pull-out strength of glued-in rods in structural timber and glulam. The comparison showed that most of the existing equations overestimate the ultimate tension loads for specimens with the rod parallel to the grain and underestimate the ultimate tension load for specimens with the rod perpendicular to the grain. The results vary because the possible CLT failure modes were not included in previous studies. Further studies are proposed to improve the equations for glued-in rods in CLT.
Keywords: glued-in rods, cross laminated timber (CLT), pull-pull experiment, glued-in length, rod-to-grain angle, failure mechanisms in CLT
Published in DiRROS: 29.11.2023; Views: 317; Downloads: 249
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