woody Dotaz Zobrazit nápovědu
Advances in behavioral biology ; Vol. 26
748 s. : il.
- Konspekt
- Psychologie
- NLK Obory
- psychologie, klinická psychologie
Resprouting multi-stemmed woody plants form an important component of the woody vegetation in many ecosystems, but a clear methodology for reliable measurement of their size and quick, non-destructive estimation of their woody biomass and carbon stock is lacking. Our goal was to find a minimum number of sprouts, i.e., the most easily obtainable, and sprout parameters that should be measured for accurate sprout biomass and carbon stock estimates. Using data for 5 common temperate woody species, we modelled carbon stock and sprout biomass as a function of an increasing number of sprouts in an interaction with different sprout parameters. The mean basal diameter of only two to five of the thickest sprouts and the basal diameter and DBH of the thickest sprouts per stump proved to be accurate estimators for the total sprout biomass of the individual resprouters and the populations of resprouters, respectively. Carbon stock estimates were strongly correlated with biomass estimates, but relative carbon content varied among species. Our study demonstrated that the size of the resprouters can be easily measured, and their biomass and carbon stock estimated; therefore, resprouters can be simply incorporated into studies of woody vegetation.
2nd ed. 877 s.
- Konspekt
- Patologie. Klinická medicína
- NLK Obory
- chemie, klinická chemie
Although many studies have shown that species richness decreases from low to high latitudes (the Latitudinal Diversity Gradient), little is known about the relationship between latitude and phylogenetic diversity. Here we examine global latitudinal patterns of phylogenetic diversity using a dataset of 459 woody and 589 herbaceous plant communities. We analysed the relationships between community phylogenetic diversity, latitude, biogeographic realm and vegetation type. Using the most recent global megaphylogeny for seed plants and the standardised effect sizes of the phylogenetic diversity metrics 'mean pairwise distance' (SESmpd) and 'mean nearest taxon distance' (SESmntd), we found that species were more closely-related at low latitudes in woody communities. In herbaceous communities, species were more closely-related at high latitudes than at intermediate latitudes, and the strength of this effect depended on biogeographic realm and vegetation type. Possible causes of this difference are contrasting patterns of speciation and dispersal. Most woody lineages evolved in the tropics, with many gymnosperms but few angiosperms adapting to high latitudes. In contrast, the recent evolution of herbaceous lineages such as grasses in young habitat types may drive coexistence of closely-related species at high latitudes. Our results show that high species richness commonly observed at low latitudes is not associated with high phylogenetic diversity.
537 s. : il. ; 26 cm
- MeSH
- chování fyziologie MeSH
- neurony fyziologie MeSH
- paměť fyziologie MeSH
- podmiňování (psychologie) fyziologie MeSH
- Publikační typ
- kongresy MeSH
- Konspekt
- Patologie. Klinická medicína
- NLK Obory
- neurovědy
- psychofarmakologie
- behaviorální vědy
Changes in land-use and climate affect the distribution and diversity of plant and animal species at different spatiotemporal scales. The extent to which species-specific phenotypic plasticity and biotic interactions mediate organismal adaptation to changing environments, however, remains poorly understood. Woody plant expansion is threatening the extent of alpine grasslands worldwide, and evaluating and predicting its effects on herbivores is of crucial importance. Here, we explore the impact of shrubification on the feeding efficiency of Pyrenean chamois (Rupicapra p. pyrenaica), as well as on the three most abundant coexisting domestic ungulate species: cattle, sheep and horses. We use observational diet composition from May to October and model different scenarios of vegetation availability where shrubland and woodland proliferate at the expense of grassland. We then predicted if the four ungulate species could efficiently utilize their food landscapes with their current dietary specificities measuring their niche breath in each scenario. We observed that the wild counterpart, due to a higher trophic plasticity, is less disturbed by shrubification compared to livestock, which rely primarily on herbaceous plants and will be affected 3.6 times more. Our results suggest that mixed feeders, such as chamois, could benefit from fallow landscapes, and that mountain farmers are at a growing economic risk worldwide due to changing land-use practices and climate conditions.
- MeSH
- býložravci fyziologie MeSH
- divoká zvířata MeSH
- dobytek fyziologie MeSH
- druhová specificita MeSH
- ekosystém MeSH
- klimatické změny MeSH
- preference v jídle MeSH
- rostliny klasifikace MeSH
- Rupicapra fyziologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
Parenchyma represents a critically important living tissue in the sapwood of the secondary xylem of woody angiosperms. Considering various interactions between parenchyma and water transporting vessels, we hypothesize a structure-function relationship between both cell types. Through a generalized additive mixed model approach based on 2,332 woody angiosperm species derived from the literature, we explored the relationship between the proportion and spatial distribution of ray and axial parenchyma and vessel size, while controlling for maximum plant height and a range of climatic factors. When factoring in maximum plant height, we found that with increasing mean annual temperatures, mean vessel diameter showed a positive correlation with axial parenchyma proportion and arrangement, but not for ray parenchyma. Species with a high axial parenchyma tissue fraction tend to have wide vessels, with most of the parenchyma packed around vessels, whereas species with small diameter vessels show a reduced amount of axial parenchyma that is not directly connected to vessels. This finding provides evidence for independent functions of axial parenchyma and ray parenchyma in large vesselled species and further supports a strong role for axial parenchyma in long-distance xylem water transport.
AIMS: Determine the extent to which buprenorphine injectors continue treatment with buprenorphine-naloxone or methadone, and the impact of these treatments on substance use and HIV risk in the Republic of Georgia. METHODS: Randomized controlled 12-week trial of daily-observed methadone or buprenorphine-naloxone followed by a dose taper, referral to ongoing treatment, and follow-up at week 20 at the Uranti Clinic in Tbilisi, Republic of Georgia. Eighty consenting treatment-seeking individuals (40/group) aged 25 and above who met ICD-10 criteria for opioid dependence with physiologic features and reported injecting buprenorphine 10 or more times in the past 30 days. Opioid use according to urine tests and self-reports, treatment retention, and HIV risk behavior as determined by the Risk Assessment Battery. RESULTS: Mean age of participants was 33.7 (SD5.7), 4 were female, mean history of opioid injection use was 5.8 years (SD4.6), none were HIV+ at intake or at the 12-week assessment and 73.4% were HCV+. Sixty-eight participants (85%) completed the 12-week medication phase (33 from methadone and 35 from buprenorphine/naloxone group); 37 (46%) were in treatment at the 20-week follow-up (21 from methadone and 16 from the buprenorphine/naloxone group). In both study arms, treatment resulted in a marked reduction in unprescribed buprenorphine, other opioid use, and HIV injecting risk behavior with no clinically significant differences between the two treatment arms. CONCLUSIONS: Daily observed methadone or buprenorphine-naloxone are effective treatments for non-medical buprenorphine and other opioid use in the Republic of Georgia and likely to be useful for preventing HIV infection.
- MeSH
- buprenorfin terapeutické užití MeSH
- dospělí MeSH
- hepatitida C epidemiologie MeSH
- HIV infekce psychologie přenos MeSH
- intravenózní abúzus drog farmakoterapie psychologie MeSH
- lidé MeSH
- methadon terapeutické užití MeSH
- narkotika terapeutické užití MeSH
- odhalování abúzu drog MeSH
- opiátová substituční terapie * MeSH
- poruchy spojené s užíváním opiátů farmakoterapie MeSH
- riskování * MeSH
- společné užívání jehel statistika a číselné údaje MeSH
- výsledek terapie MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- randomizované kontrolované studie MeSH
- Research Support, N.I.H., Extramural MeSH
- Geografické názvy
- Gruzie MeSH
