This paper presents a new approach to identifying the climate variables that influence the size of the area burned by forest wildfires.Multiple linear regression was used in combination with nonlinear variable transfo...This paper presents a new approach to identifying the climate variables that influence the size of the area burned by forest wildfires.Multiple linear regression was used in combination with nonlinear variable transformations to determine relevant nonlinear forest wildfire size functions.Data from the Prague-East District of the Czech Republic was used for model derivation.Individual burned forest area was hypothesized as a function of water vapor pressure,air temperature and wind speed.Wind speed was added to enhance predictions of the size of forest wildfires,and further improvements to the utility of prediction methods were added to the regression equation.The results show that if the air temperature increases,it may contain less water and the fuel will become drier.The size of the burned area then increases.If the relative humidity in the air increases and the wind speed decreases,the size of the burned area is reduced.Our model suggests that changes in the climate factors caused by ongoing climate change could cause significant changes in the size of wildfire in forests.展开更多
Xylariaceous endophytes are commonly encountered in plants,and it has recently been found out that insect vectors play a major role in their life cycle,as well as in the apparent host-specificity of the fungal stromat...Xylariaceous endophytes are commonly encountered in plants,and it has recently been found out that insect vectors play a major role in their life cycle,as well as in the apparent host-specificity of the fungal stromata.In this study,a new insect-associated,endophytic anamorph species of Daldinia is recognised from a comparison of (a)morphological and ecological data;(b)molecular phylogenetic data based on rDNA,alpha-actin and beta-tubulin genes;and (c)secondary metabolite profiles based on high performance liquid chromatography/diode array/mass spectrometry(HPLC-DAD/MS)and gas chromatography/mass spectrometry(GC-MS)in comparison with authentic strains of Daldinia and other Xylariaceae.The new species,Daldinia hawksworthii,is a symbiont of the willow woodwasp,Xiphydria prolongata,which is in turn preferentially associated with Salix.A comparison of HPLCDAD/MS profiles from standardised cultures revealed the presence of a specific compound,which was not encountered in any of the ca.250 Daldinia strains studied for comparison.This compound was isolated after fermentation of the fungus in 10 l scale by preparative chromatography.Structure elucidation by NMR spectroscopy revealed a novel pyrone,for which the name dalsymbiopyrone is proposed.The compound showed weak antimicrobial and cytotoxic effects and might be a signal molecule involved in the trilateral ecological interaction between the host plant,the insect,and its fungal symbiont.展开更多
基金funded by grant"EVA4.0",No.CZ.02.1.01/0.0/0.0/16_019/0000803 financed by the Operational Program Research,Development and Education(OP RDE),the Ministry of Education of the Czech Republic。
文摘This paper presents a new approach to identifying the climate variables that influence the size of the area burned by forest wildfires.Multiple linear regression was used in combination with nonlinear variable transformations to determine relevant nonlinear forest wildfire size functions.Data from the Prague-East District of the Czech Republic was used for model derivation.Individual burned forest area was hypothesized as a function of water vapor pressure,air temperature and wind speed.Wind speed was added to enhance predictions of the size of forest wildfires,and further improvements to the utility of prediction methods were added to the regression equation.The results show that if the air temperature increases,it may contain less water and the fuel will become drier.The size of the burned area then increases.If the relative humidity in the air increases and the wind speed decreases,the size of the burned area is reduced.Our model suggests that changes in the climate factors caused by ongoing climate change could cause significant changes in the size of wildfire in forests.
基金support from COST Action FA1103“Endophytes in Biotechnologiy and Agriculture”.
文摘Xylariaceous endophytes are commonly encountered in plants,and it has recently been found out that insect vectors play a major role in their life cycle,as well as in the apparent host-specificity of the fungal stromata.In this study,a new insect-associated,endophytic anamorph species of Daldinia is recognised from a comparison of (a)morphological and ecological data;(b)molecular phylogenetic data based on rDNA,alpha-actin and beta-tubulin genes;and (c)secondary metabolite profiles based on high performance liquid chromatography/diode array/mass spectrometry(HPLC-DAD/MS)and gas chromatography/mass spectrometry(GC-MS)in comparison with authentic strains of Daldinia and other Xylariaceae.The new species,Daldinia hawksworthii,is a symbiont of the willow woodwasp,Xiphydria prolongata,which is in turn preferentially associated with Salix.A comparison of HPLCDAD/MS profiles from standardised cultures revealed the presence of a specific compound,which was not encountered in any of the ca.250 Daldinia strains studied for comparison.This compound was isolated after fermentation of the fungus in 10 l scale by preparative chromatography.Structure elucidation by NMR spectroscopy revealed a novel pyrone,for which the name dalsymbiopyrone is proposed.The compound showed weak antimicrobial and cytotoxic effects and might be a signal molecule involved in the trilateral ecological interaction between the host plant,the insect,and its fungal symbiont.
