31. A comparison of radial increment and wood density from beech provenance trials in Slovenia and HungaryLuka Krajnc, Peter Prislan, Gregor Božič, Marjana Westergren, Domen Arnič, Csaba Mátyás, Jožica Gričar, Hojka Kraigher, 2022, izvirni znanstveni članek Povzetek: Provenance trials are a valuable source of information, especially in species such as European beech (Fagus sylvatica L.), which will likely increase its distribution due to global warming. The current study compares radial increment and wood density of beech provenances in the juvenile development stage from contrasting environments in Europe (Belgium, Slovenia, Czech Republic, Italy) planted at a mesic to wet site in Slovenia and a xeric site in Hungary. Existing data (past measurements of diameters and height) were combined with new measurements of tree height, diameter, dendrochronological and resistance drilling density measurements to assess differences in provenance radial growth. The wood density data were evaluated using a Bayesian general linear model. In order to study the differences in radial increment in more detail, two weather-wise contrasting years (2014 and 2017) were selected from the last decade, based on calculations of the 12-month Standardized Precipitation-Evapotranspiration Index. The differences in average tree-ring width among provenances at each sampled site appeared to be relatively small when averaged over a whole decade of data. However, according to year-to-year data, some provenances grew faster than others, especially in favorable weather conditions. In unfavorable conditions, the differences in tree-ring widths among provenances were smaller. For most provenances, variation in tree-ring widths within the same provenance increased in unfavorable conditions. The difference between the provenances with the highest and lowest wood densities at both locations did not exceed 5%. The model results indicate that the Idrija (Slovenia) provenance probably has a higher median wood density than other studied provenances at both sites. Although the current study confirmed some differences in wood density between provenances and trial locations, the differences are negligible in practice due to their low magnitude and the fact that the analyzed trees were still juvenile. As beech has a diffuse-porous wood, negligible differences in wood density would also be expected in adult trees. Beech provenances for planting in relation to changing weather should probably be chosen for their ability to survive more extreme weather events rather than to improve radial increment or wood density, especially as the differences in wood density of juvenile trees are relatively small.
Ključne besede: Fagus sylvatica, tree-ring width, common garden, resistance drilling
Objavljeno v DiRROS: 15.04.2022; Ogledov: 650; Prenosov: 481
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32. Nrf2-interacting nutrients and COVID-19 : time for research to develop adaptation strategiesJean Bousquet, Jean-Paul Cristol, Wienczyslawa Czarlewski, Josep M. Antò i Boquè, Adrian Martineau, Tari Haahtela, Susana C. Fonseca, Guido Iaccarino, Hubert Blain, Alessandro Fiocchi, Nisera Bajrović, Natalija Edelbaher, Maja Jošt, Peter Kopač, Anja Koren, Mitja Košnik, Karmen Kramer Vrščaj, Samo Kreft, Nika Lalek, Bojan Madjar, Tonka Poplas-Susič, Irma Rozman Sinur, Tanja Soklič, Katja Triller Vadnal, Nadja Triller, Jure Urbančič, Mihaela Zidarn, 2020, pregledni znanstveni članek Povzetek: There are large between- and within-country variations in COVID-19 death rates. Some very low death rate settings such as Eastern Asia, Central Europe, the Balkans and Africa have a common feature of eating large quantities of fermented foods whose intake is associated with the activation of the Nrf2 (Nuclear factor (erythroid-derived 2)-like 2) anti-oxidant transcription factor. There are many Nrf2-interacting nutrients (berberine, curcumin, epigallocatechin gallate, genistein, quercetin, resveratrol, sulforaphane) that all act similarly to reduce insulin resistance, endothelial damage, lung injury and cytokine storm. They also act on the same mechanisms (mTOR: Mammalian target of rapamycin, PPAR[gamma]:Peroxisome proliferator-activated receptor, NF[kappa]B: Nuclear factor kappa B, ERK: Extracellular signal-regulated kinases and eIF2[alpha]:Elongation initiation factor 2[alpha]). They may as a result be important in mitigating the severity of COVID-19, acting through the endoplasmic reticulum stress or ACE-Angiotensin-II-AT1R axis (AT1R) pathway. Many Nrf2-interacting nutrients are also interacting with TRPA1 and/or TRPV1. Interestingly, geographical areas with very low COVID-19 mortality are those with the lowest prevalence of obesity (Sub-Saharan Africa and Asia). It is tempting to propose that Nrf2-interacting foods and nutrients can re-balance insulin resistance and have a significant effect on COVID-19 severity. It is therefore possible that the intake of these foods may restore an optimal natural balance for the Nrf2 pathway and may be of interest in the mitigation of COVID-19 severity.
Ključne besede: Covid-19, SARS-CoV-2, food, insulin resistance, obesity, Nrf2, nutrients, TRPA1
Objavljeno v DiRROS: 25.01.2021; Ogledov: 1661; Prenosov: 636
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33. The effect of bedrock and species mixture on wood density and radial wood increment in pubescent oak and black pineLuka Krajnc, Polona Hafner, Jožica Gričar, 2020, izvirni znanstveni članek Povzetek: Wood density and radial wood increment were examined in trees of pubescent oak (Quercus pubescens Willd.) and black pine (Pinus nigra Arnold., subsp. nigra) in relation to stand mixture and underlying bedrock. Trees of both species from pure and mixed stands were sampled across two types of bedrock, limestone and flysch. Trees from each species were similar in age. Wood density was estimated in standing trees using resistance drilling and increment cores were taken from a smaller subsample of trees of both species. Tree-ring, earlywood and latewood widths were measured and compared to radial profiles of wood density. The influence of stand mixture, diameter at breast height and bedrock on wood density was examined using a Bayesian general linear model. Wood density was significantly higher in pubescent oak than in black pine. Stand mixture was found to affect wood density positively, although the magnitude of the effect was relatively small when compared to other influencing factors also included in the current study. The effect of diameter on wood density was positive on both bedrocks in pubescent oak and negative or neutral in black pine. The size of the effect varied by bedrock and species. On flysch bedrock, the influence of diameter on wood density was stronger than it was on limestone. These indirect bedrock effects on wood density are probably a result of different soil fertility rather than the bedrock itself. There was a notable difference in radial wood increment in both species across the two bedrocks, whereas the differences in densities were smaller. Higher wood densities found on flysch in the subsample of pubescent oaks are likely an effect of higher proportions of latewood, while the opposite trend was observed in black pine. Higher wood density was found on limestone in black pine despite higher latewood percentages on flysch. In the context of forest management, the species composition of the naturally occurring mixtures in the sub-Mediterranean region should be adjusted slightly to favor pubescent oak, since it is a climax species and will bind more carbon for longer than black pine due to higher wood densities. Future forest management should also promote the overall development of pubescent oak trees in sub-Mediterranean stands. The results are especially important in the European context, because the share of sub-Mediterranean stands is expected to rise with global warming.
Ključne besede: Karst, wood structure, resistograph, resistance drilling, Quercus pubescens, Pinus nigra, limestone, flysch
Objavljeno v DiRROS: 14.01.2021; Ogledov: 1124; Prenosov: 385
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34. Decontamination strategies and bloodstream infections with antibiotic-resistant microorganisms in ventilated patients : a randomized clinical trialBastiaan H. Wittekamp, Nienke L. Plantinga, Ben S. Cooper, Joaquin Lopez-Contreras, Pere Coll, Jordi Mancebo, Matt P. Wise, Matt P. G. Morgan, Pieter Depuydt, Jerina Boelens, Viktorija Tomič, Franc Šifrer, 2018, izvirni znanstveni članek Povzetek: Importance: The effects of chlorhexidine (CHX) mouthwash, selective oropharyngeal decontamination (SOD), and selective digestive tract decontamination (SDD) on patient outcomes in ICUs with moderate to high levels of antibiotic resistance are unknown. Objective: To determine associations between CHX 2%, SOD, and SDD and the occurrence of ICU-acquired bloodstream infections with multidrug-resistant gram-negative bacteria (MDRGNB) and 28-day mortality in ICUs with moderate to high levels of antibiotic resistance. Design, setting, and participants: Randomized trial conducted from December 1, 2013, to May 31, 2017, in 13 European ICUs where at least 5% of bloodstream infections are caused by extended-spectrum [beta]-lactamase-producing Enterobacteriaceae. Patients with anticipated mechanical ventilation of more than 24 hours were eligible. The final date of follow-up was September 20, 2017. Interventions: Standard care was daily CHX 2% body washings and a hand hygiene improvement program. Following a baseline period from 6 to 14 months, each ICU was assigned in random order to 3 separate 6-month intervention periods with either CHX 2% mouthwash, SOD (mouthpaste with colistin, tobramycin, and nystatin), or SDD (the same mouthpaste and gastrointestinal suspension with the same antibiotics), all applied 4 times daily. Main outcomes and measures: The occurrence of ICU-acquired bloodstream infection with MDRGNB (primary outcome) and 28-day mortality (secondary outcome) during each intervention period compared with the baseline period. Results: A total of 8665 patients (median age, 64.1 years; 5561 men [64.2%]) were included in the study (2251, 2108, 2224, and 2082 in the baseline, CHX, SOD, and SDD periods, respectively). ICU-acquired bloodstream infection with MDRGNB occurred among 144 patients (154 episodes) in 2.1%, 1.8%, 1.5%, and 1.2% of included patients during the baseline, CHX, SOD, and SDD periods, respectively. Absolute risk reductions were 0.3% (95% CI, -0.6% to 1.1%), 0.6% (95% CI, -0.2% to 1.4%), and 0.8% (95% CI, 0.1% to 1.6%) for CHX, SOD, and SDD, respectively, compared with baseline. Adjusted hazard ratios were 1.13 (95% CI, 0.68-1.88), 0.89 (95% CI, 0.55-1.45), and 0.70 (95% CI, 0.43-1.14) during the CHX, SOD, and SDD periods, respectively, vs baseline. Crude mortality risks on day 28 were 31.9%, 32.9%, 32.4%, and 34.1% during the baseline, CHX, SOD, and SDD periods, respectively. Adjusted odds ratios for 28-day mortality were 1.07 (95% CI, 0.86-1.32), 1.05 (95% CI, 0.85-1.29), and 1.03 (95% CI, 0.80-1.32) for CHX, SOD, and SDD, respectively, vs baseline. Conclusions and relevance: Among patients receiving mechanical ventilation in ICUs with moderate to high antibiotic resistance prevalence, use of CHX mouthwash, SOD, or SDD was not associated with reductions in ICU-acquired bloodstream infections caused by MDRGNB compared with standard care.
Ključne besede: anti-infective agents -- therapeutic use, bacteremia -- prevention and control, chlorhexidine -- therapeutic use, cross infection -- prevention and control, disinfection -- methods, bacterial drug resistance, gastrointestinal tract -- microbiology, Gram-negative bacterial infections -- prevention and control, hospital mortality, intensive care units, mouthwashes -- therapeutic use, oropharynx -- microbiology, artificial respiration, multicenter study, randomized controlled trial
Objavljeno v DiRROS: 09.11.2020; Ogledov: 1229; Prenosov: 398
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35. Low growth resilience to drought is related to future mortality risk in treesLucía De Soto, Maxime Cailleret, Frank Sterck, Steven Jansen, Koen Kramer, Elisabeth M.R. Robert, Tuomas Aakala, Mariano M. Amoroso, Christof Bigler, Jesus Julio Camarero, Katarina Čufar, Tom Levanič, 2020, izvirni znanstveni članek Povzetek: Severe droughts have the potential to reduce forest productivity and trigger tree mortality. Most trees face several drought events during their life and therefore resilience to dry conditions might be crucial to long-term survival. We assess how growth resilience to severe droughts, including its components resistance and recovery, is related to the ability to survive future droughts by using a tree-ring database of surviving and now-dead trees from 118 sites (22 species, >3,500 trees). We find that, across the variety of regions and species sampled, trees that died during water shortages were less resilient to previous non-lethal droughts, relative to coexisting surviving trees of the same species. In angiosperms, drought-related mortality risk is associated with lower resistance (low capacity to reduce impact of the initial drought), while it is related to reduced recovery (low capacity to attain pre-drought growth rates) in gymnosperms. The different resilience strategies in these two taxonomic groups open new avenues to improve our understanding and prediction of drought-induced mortality. Resilience to drought is crucial for tree survival under climate change. Here, DeSoto et al. show that trees that died during drought were less resilient to previous dry events compared to surviving conspecifics, but the resilience strategies differ between angiosperms and gymnosperms.
Ključne besede: trees, mortality, gymnosperms, angiosperms, drought, resilience, resistance, recovery
Objavljeno v DiRROS: 20.02.2020; Ogledov: 1758; Prenosov: 1101
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36. Evaluating short-term impacts of forest management and microsite conditions on understory vegetation in temperate fir-beech forests : floristic, ecological, and trait-based perspectiveJanez Kermavnar, Aleksander Marinšek, Klemen Eler, Lado Kutnar, 2019, izvirni znanstveni članek Povzetek: Forest understory vegetation is largely influenced by disturbances and given local abiotic conditions. Our research focuses on the early response of understory vegetation to various forest management intensities in Dinaric fir-beech forests in Slovenia: (i) control, (ii) 50% cut of stand growing stock, and (iii) 100% cut of stand growing stock. Apart from identifying overstory removal effects, we were interested in fine-scale variation of understory vegetation and environmental determinants of its species composition. Vegetation was sampled within 27 karst sinkholes, which represent a dominant landform in studied forests. Within each sinkhole, five sampling plots, varying in slope aspect (centre, north, east, south, west), were established (135 in total), where pre-treatment (in 2012) and post-treatment (in 2014) floristic surveys were conducted. The sampled understory species were characterized in terms of Ellenberg's indicator values (EIVs) and plant functional traits (plant height, seed mass, specific leaf area, leaf dry matter content). Diversity metrics (species richness, total cover, Shannon index) increased in plots where the silvicultural measures were applied. Tree species richness also increased in 100% cutting. A redundancy analysis revealed that species composition was related to environmental variables, which are directly influenced by management interventions (overstory canopy cover, microclimate maximum daily temperature, soil properties thickness of organic soil layer) as well as by topographic factors (slope inclination and surface rockiness). EIVs for light were significantly affected by treatment intensity, whereas soil-related EIVs (moisture, reaction, nutrients) depended more on the within-sinkhole position. Canopy gaps, compared with uncut control plots, hosted a higher number of colonizing species with a higher plant height and smaller seeds, while leaf traits did not show a clear response. We found a negative correlation between pre-treatment species (functional) richness and post-treatment shifts in floristic (functional) composition. Plots with higher richness exhibited smaller changes compared with species-poor communities. Incorporating different perspectives, the results of this study offer valuable insights into patterns of understory vegetation response to forest management in fir-beech forests.
Ključne besede: canopy gap, microsite environment, Ellenberg indicator values, plant functional traits, compositional resistance, karst topography, fir-beech forest
Objavljeno v DiRROS: 06.12.2019; Ogledov: 2500; Prenosov: 1571
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