Radial head and neck fractures represent up to 14%of all pediatric elbow fractures and can be a difficult challenge in the pediatric patient.In up to 39%of proximal radius fractures,there is a concomitant fracture,whi...Radial head and neck fractures represent up to 14%of all pediatric elbow fractures and can be a difficult challenge in the pediatric patient.In up to 39%of proximal radius fractures,there is a concomitant fracture,which can easily be overlooked on the initial standard radiographs.The treatment options for proximal radius fractures in children range from non-surgical treatment,such as immobilization alone and closed reduction followed by immobilization,to more invasive options,including closed reduction with percutaneous pinning and open reduction with internal fixation.The choice of treatment depends on the degree of angulation and displacement of the fracture and the age of the patient;an angulation of less than 30 degrees and translation of less than 50%is generally accepted,whereas a higher degree of displacement is considered an indication for surgical intervention.Fractures with limited displacement and non-surgical treatment generally result in superior outcomes in terms of patient-reported outcome measures,range of motion and complications compared to severely displaced fractures requiring surgical intervention.With proper management,good to excellent results are achieved in most cases,and long-term sequelae are rare.However,severe complications do occur,including radio-ulnar synostosis,osteonecrosis,rotational impairment,and premature physeal closure with a malformation of the radial head as a result,especially after more invasive procedures.Adequate follow-up is therefore warranted.展开更多
A case of osteoid osteoma of the elbow in a patient with hemophilia A is described. This male patient presented with chronic and nocturnal pain of the left elbow which was alleviated with acetaminophen. Besides pain, ...A case of osteoid osteoma of the elbow in a patient with hemophilia A is described. This male patient presented with chronic and nocturnal pain of the left elbow which was alleviated with acetaminophen. Besides pain, he also complained of stiffness. Before these complaints, he had recurrent bleedings in the elbow because of hemophilia. A delayed diagnosis of osteoid osteoma in the proximal part of the left ulna was established by a bone scan and a multislice spiral computed tomography(CT) scan. The lesion was surgically removed under CT-guidance. The histopathological analyses did not show specific features of osteoid osteoma. Two months after the operation, the complaints decreased and the range of motion of the left elbow improved. A diagnosis of osteoid osteoma of the elbow should be considered in young adult patients with persistent elbow pain and histological confirmation is not always necessary.展开更多
Tau plays a crucial role in several neurodegenerative diseases,collectively referred to as tauopathies.Therefore,targeting potential pathological changes in tau could enable useful therapeutic interventions.However,ta...Tau plays a crucial role in several neurodegenerative diseases,collectively referred to as tauopathies.Therefore,targeting potential pathological changes in tau could enable useful therapeutic interventions.However,tau is not an easy target because it dynamically interacts with microtubules and other cellular components,which presents a challenge for tau-targeted drugs.New cellular models could aid the development of mechanism-based tau-targeted therapies.展开更多
The implementation of photoinduced linkage isomerism in molecular-based optical materials represents a promising approach for the synthesis of high-contrast,high-resolution photosensitive materials that are necessary...The implementation of photoinduced linkage isomerism in molecular-based optical materials represents a promising approach for the synthesis of high-contrast,high-resolution photosensitive materials that are necessary for high-density(holographic)data storage and/or real-three-dimensional(holographic)displays.The unsolved task of embedding a photofunctional coordination complex into a matrix like polymer polydimethylsiloxane(PDMS)with photoinduced isomerism of a SO-bond in the sulfoxide compoundRubpy2OSOPF6 is addressed.This approach allows to preserve the spectral properties within the solid dielectric environment,with an impact of PDMS on population and relaxation dynamics.All data are discussed in the framework of photofunctionality,storage,and display applications.展开更多
Commercially managed forests are often poor in terms of biodiversity.Saproxylic beetle species could be a useful bioindicating group for the conservation of forest stands.In recent decades,oak stands have been affecte...Commercially managed forests are often poor in terms of biodiversity.Saproxylic beetle species could be a useful bioindicating group for the conservation of forest stands.In recent decades,oak stands have been affected by a wide range of factors that have intensified stand decline.Saproxylic beetle richness was investigated in declining oak stands that have been consequently targeted for clearcutting due to concerns about insect pest outbreaks.The research was conducted at six managed oak forests,where we compared beetle occurrences in declining stands and in healthy stands that did not show any symptoms of decline.Beetles were collected using window traps placed on the basal and mid-trunk sections of trees.A total of 2925 adults belonging to 239 saproxylic beetle species were captured,of which 56 species are on the IUCN Red List.The results show that declining stands were richer in saproxylic species,and that the diversity of beetle species was greater in these stands.Approximately 1.4 times more species were caught within declining stands than in healthy ones(1.6 times for Red List species).Declining stands hosted more pest species(e.g.,cambiophagous and xylophagous species).However,only low numbers of these species were recorded in these stands.In summary,results of this study suggest that decline of managed oak stands is creating a wide spectrum of habitats for many saproxylic species.Thus,salvage logging of declining oak trees can represent a natural trap and reduce local beetle biodiversity,mainly for saproxylic,endangered or low-mobility species that would be attracted by new suitable habitats.展开更多
While numerous allometric models exist for estimating biomass in trees with single stems,models for multi-stemmed species are scarce.This study presents models for predicting aboveground biomass(AGB)in European hazel(...While numerous allometric models exist for estimating biomass in trees with single stems,models for multi-stemmed species are scarce.This study presents models for predicting aboveground biomass(AGB)in European hazel(Corylus avellana L.),growing in multi-stemmed shrub form.We measured the size and harvested the biomass of 30 European hazel shrubs,drying and weighing their woody parts and leaves separately.AGB(dry mass)and leaf area models were established using a range of predictors,such as the upper height of the shrub,number of shoots per shrub,canopy projection area,stem base diameter of the thickest stem,and the sum of cross-sectional areas of all stems at the stem base.The latter was the best predictor of AGB,but the most practically useful variables,defined as relatively easy to measure by terrestrial or aerial approaches,were the upper height of the shrub and the canopy projection area.The leaf biomass to AGB ratio decreased with the shrub's height.Specific leaf area of shaded leaves increases with shrub height,but that of leaves at the top of the canopy does not change significantly.Given that the upper shrub height and crown projection of European hazel can be estimated using remote sensing approaches,especially UAV and LIDAR,these two variables appear the most promising for effective measurement of AGB in hazel.展开更多
A recent publication by Zhou et al.[1]in Neuron demonstrates that a specific interaction between astrocytes and a subtype of neurons has an influence on complex animal behavior,namely risk assessment.The majority of n...A recent publication by Zhou et al.[1]in Neuron demonstrates that a specific interaction between astrocytes and a subtype of neurons has an influence on complex animal behavior,namely risk assessment.The majority of neuroscientists analyzing the molecular and cellular substrate of behavior focus on neuronal circuits.Glial cells were originally described by Rudolf Virchow and the name glia refers to the Greek word for glue or putty.Thus,glial cells were long thought to represent simply the filling stuff of the brain.This view has changed dramatically in the last decades.The three major types of glial cells of the central nervous system fulfll diverse functions.Oligodendrocytes are the myelinforming cells and it has become evident that they are plastic and are able to influence neuronal connectivity.Microglia are the immune cells of the brain and interact with synapses during development,in plasticity,and very prominently in any disease of the nervous system.展开更多
Propofol(2,6-di-isopropylphenol) is a short-acting,intravenous sedative drug.^([1,2]) The pharmacologic mechanism of propofol is related to its agonistic effects on the gamma-amino butyric acid receptor.^([1-3]) Propo...Propofol(2,6-di-isopropylphenol) is a short-acting,intravenous sedative drug.^([1,2]) The pharmacologic mechanism of propofol is related to its agonistic effects on the gamma-amino butyric acid receptor.^([1-3]) Propofol injection pain(PIP) is well-known in the operating room and is commonly countered by the prophylactic administration of lidocaine.In anesthesia,PIP is encountered in 28%–90% of patients.^([4,5]) However,PIPprophylaxis does not seem to be efficacious in every population.^([6,7]) Whether procedural sedation and analgesia(PSA) in the emergency department(ED) warrants lidocaine administration is unclear.展开更多
In this paper,we investigate the distinctions between dynamical quantum chaotic systems and random models from the perspective of observable properties,particularly focusing on the eigenstate thermalization hypothesis...In this paper,we investigate the distinctions between dynamical quantum chaotic systems and random models from the perspective of observable properties,particularly focusing on the eigenstate thermalization hypothesis(ETH).Through numerical simulations,we find that for dynamical systems,the envelope function of off-diagonal elements of observables exhibits an exponential decay at largeΔE,while for randomized models,it tends to be flat.We demonstrate that the correlations of chaotic eigenstates,originating from the delicate structures of Hamiltonians,play a crucial role in the non-trivial structure of the envelope function.Furthermore,we analyze the numerical results from the perspective of the dynamical group elements in Hamiltonians.Our findings highlight the importance of correlations in physical chaotic systems and provide insights into the deviations from random matrix theory(RMT)predictions.These understandings offer valuable directions for future research.展开更多
We used fast chlorophyll fluorescence transients(OJIP) to study provenance-related differences in photosynthetic performance and the magnitude of day-to-day chlorophyll fluorescence(ChlF) variation in northern(67°...We used fast chlorophyll fluorescence transients(OJIP) to study provenance-related differences in photosynthetic performance and the magnitude of day-to-day chlorophyll fluorescence(ChlF) variation in northern(67°N)and southern(62°N) silver birches in a common garden at62°N.ChlF transients were measured five times during two weeks in the middle of summer to avoid seasonal variation.Differences in growth and leaf morphological traits between the provenances were also examined.The northern trees had higher chlorophyll content,larger leaf areas,and higher leaf fresh and dry mass than the southern trees,but the leaf mass per area did not differ between the provenances.The southern trees were taller and showed higher annual shoot growth than the northern trees.For all the ChlF parameters,day-to-day variation was significant and followed the same pattern for both provenances with no significant provenance ×day interaction,suggesting a similar response to environmental variation.The northern provenance had higher values in parameters related to the reduction of end electron acceptors at the Photosystem I(PSI) acceptor side as probed by ChlF.This and higher values for performance indices PI_(abs) and PI_(tot) in northern than in southern trees suggest higher photosynthetic performance of northern trees in line with the latitudinal compensation strategy.Provenance differences in these parameters increased towards the end of the measurement period,suggesting preparation for earlier growth cessation in northern trees triggered by the shortening day length.The study shows that provenance differences in ChlF can be relatively stable regardless of environmental variation but might be influenced by physiological alterations in preparation for future changes in environmental conditions.展开更多
Understanding the ecological processes shaping competitive interactions among forest trees is crucial for predicting ecosystem productivity and climate change resilience.However,few studies have investigated how the b...Understanding the ecological processes shaping competitive interactions among forest trees is crucial for predicting ecosystem productivity and climate change resilience.However,few studies have investigated how the biological attributes of tropical species may affect competitive outcomes under varying resource conditions.We collected and analysed a 10-year dataset of radial growth rates in canopy trees from a network of forest inventory plots located in divergent forest types over an extensive meteorological gradient in Ghana,West Africa.We used nonlinear models to estimate the relative reduction in potential growth(basal area increment)of individual target trees of a given species as a consequence of the combined effects of(1)target tree size,(2)variation in crowding levels by neighbouring trees,(3)the functional attributes of those neighbours(wood density and shade tolerance),and(4)local soil moisture levels.Analyses were conducted separately for the 15 most common species in the inventory network.In opposition to neutral theory,our findings indicate that the strength of interactions among competing species was distinctly asymmetric and dynamic.Wood density was an important characteristic that modified competitive outcomes for most species,particularly under varying levels of resource availability.Specifically,dense wood was an attribute that conferred comparatively stronger competitive ability in moisture-limited conditions.Larger individuals were notably less sensitive to the effects of moisture-dependent competition.Our results suggest that attributes such as wood density may reflect divergent life history strategies that differentiate species’fitness and competitive ability in varying environments.The dynamic nature of competition,influenced by a complex interplay of biological and abiotic factors,implies that more prevalent dry periods,which have been forecast for tropical Africa,may impact the physiognomy and function of future forest communities in the region.展开更多
Sessile oak(Quercus petraea(Matt.)Liebl.)is widely distributed across most of Europe particularly the hills and lower mountain ranges,so is considered“the oak of the mountains”.This species grows on a wide variety o...Sessile oak(Quercus petraea(Matt.)Liebl.)is widely distributed across most of Europe particularly the hills and lower mountain ranges,so is considered“the oak of the mountains”.This species grows on a wide variety of soils and at altitudes ranging from sea level to 2200 m,especially in Atlantic and sub-Mediterranean climates,and it is sensitive to low winter temperatures,early and late frosts,as well as high summer temperatures.Sessile oak forms both pure and mixed stands especially with broadleaves such as European beech,European hornbeam,small-leaved lime and Acer spp.These form the understorey of sessile oak stands,promoting the natural shedding of lower branches of the oak and protecting the trunk against epicormic branches.Sessile oak is a long-lived,light-demanding and wind-firm species,owing to its taproot and heart-shaped root system.Its timber,one of the most valuable in Europe,is important for fur-niture-making(both solid wood and veneer),construction,barrels,railway sleepers,and is also used as fuelwood.It is one of the few major tree species in Europe that is regener-ated by seed(naturally or artificially)and by stump shoots in high forest,coppice-with-standards and coppice forests.Sessile oak forests are treated in both regular and irregular systems involving silvicultural techniques such as uniform shelterwood,group shelterwood,irregular shelterwood,irregular high forest,coppice-with-standards and simple coppice.Young naturally regenerated stands are managed by weeding,release cutting and cleaning-respacing,keeping the stands quite dense for good natural pruning.Plantations are based on(1)2-4-year old bare-root or container-grown seedlings produced in nurseries using seeds from genetic resources,seed stands and seed orchards.The density of sessile oak plantations(mostly in rows,but also in clusters)is usually between 4000 and 6000 ind.ha^(−1).Sessile oak silviculture of mature stands includes crown thinning,focus-ing on final crop trees(usually a maximum of 100 ind.ha^(−1))and targeting the production of large-diameter and high quality trees at long rotation ages(mostly over 120 years,sometimes 250-300 years).In different parts of Europe,conversion of simple coppices and coppice-with-standards to high forests is continuing.Even though manage-ment of sessile oak forests is very intensive and expensive,requiring active human intervention,the importance of this species in future European forests will increase in the con-text of climate change due to its high resistance to distur-bance,superior drought tolerance and heat stress resistance.展开更多
How to quickly predict an individual’s behavioral choices is an important issue in the field of human behavior research.Using noninvasive electroencephalography,we aimed to identify neural markers in the prior outcom...How to quickly predict an individual’s behavioral choices is an important issue in the field of human behavior research.Using noninvasive electroencephalography,we aimed to identify neural markers in the prior outcome-evaluation stage and the current option-assessment stage of the chicken game that predict an individual’s behavioral choices in the subsequent decision-output stage.Hierarchical linear modeling-based brain-behavior association analyses revealed that midfrontal theta oscillation in the prior outcome-evaluation stage positively predicted subsequent aggressive choices;also,beta oscillation in the current option-assessment stage positively predicted subsequent cooperative choices.These findings provide electrophysiological evidence for the three-stage theory of decision-making and strengthen the feasibility of predicting an individual’s behavioral choices using neural oscillations.展开更多
文摘Radial head and neck fractures represent up to 14%of all pediatric elbow fractures and can be a difficult challenge in the pediatric patient.In up to 39%of proximal radius fractures,there is a concomitant fracture,which can easily be overlooked on the initial standard radiographs.The treatment options for proximal radius fractures in children range from non-surgical treatment,such as immobilization alone and closed reduction followed by immobilization,to more invasive options,including closed reduction with percutaneous pinning and open reduction with internal fixation.The choice of treatment depends on the degree of angulation and displacement of the fracture and the age of the patient;an angulation of less than 30 degrees and translation of less than 50%is generally accepted,whereas a higher degree of displacement is considered an indication for surgical intervention.Fractures with limited displacement and non-surgical treatment generally result in superior outcomes in terms of patient-reported outcome measures,range of motion and complications compared to severely displaced fractures requiring surgical intervention.With proper management,good to excellent results are achieved in most cases,and long-term sequelae are rare.However,severe complications do occur,including radio-ulnar synostosis,osteonecrosis,rotational impairment,and premature physeal closure with a malformation of the radial head as a result,especially after more invasive procedures.Adequate follow-up is therefore warranted.
文摘A case of osteoid osteoma of the elbow in a patient with hemophilia A is described. This male patient presented with chronic and nocturnal pain of the left elbow which was alleviated with acetaminophen. Besides pain, he also complained of stiffness. Before these complaints, he had recurrent bleedings in the elbow because of hemophilia. A delayed diagnosis of osteoid osteoma in the proximal part of the left ulna was established by a bone scan and a multislice spiral computed tomography(CT) scan. The lesion was surgically removed under CT-guidance. The histopathological analyses did not show specific features of osteoid osteoma. Two months after the operation, the complaints decreased and the range of motion of the left elbow improved. A diagnosis of osteoid osteoma of the elbow should be considered in young adult patients with persistent elbow pain and histological confirmation is not always necessary.
文摘Tau plays a crucial role in several neurodegenerative diseases,collectively referred to as tauopathies.Therefore,targeting potential pathological changes in tau could enable useful therapeutic interventions.However,tau is not an easy target because it dynamically interacts with microtubules and other cellular components,which presents a challenge for tau-targeted drugs.New cellular models could aid the development of mechanism-based tau-targeted therapies.
基金This work was financially supported by the Deutsche Forschungsgemeinschaft(project INST 190/137-1)and the Ministry of Science and Culture of Lower Saxony(MWK).
文摘The implementation of photoinduced linkage isomerism in molecular-based optical materials represents a promising approach for the synthesis of high-contrast,high-resolution photosensitive materials that are necessary for high-density(holographic)data storage and/or real-three-dimensional(holographic)displays.The unsolved task of embedding a photofunctional coordination complex into a matrix like polymer polydimethylsiloxane(PDMS)with photoinduced isomerism of a SO-bond in the sulfoxide compoundRubpy2OSOPF6 is addressed.This approach allows to preserve the spectral properties within the solid dielectric environment,with an impact of PDMS on population and relaxation dynamics.All data are discussed in the framework of photofunctionality,storage,and display applications.
基金supported by grant No.QL24020204funded by the Ministry of Agriculture of the Czech Republic and Internal Grant Agency of Faculty of Forestry and Wood Science CZU(reg.no.A_01_22)"EVA 4.0"No.CZ.02.1.01/0.0/0.0/16_019/0000803 financed by OP RDE.
文摘Commercially managed forests are often poor in terms of biodiversity.Saproxylic beetle species could be a useful bioindicating group for the conservation of forest stands.In recent decades,oak stands have been affected by a wide range of factors that have intensified stand decline.Saproxylic beetle richness was investigated in declining oak stands that have been consequently targeted for clearcutting due to concerns about insect pest outbreaks.The research was conducted at six managed oak forests,where we compared beetle occurrences in declining stands and in healthy stands that did not show any symptoms of decline.Beetles were collected using window traps placed on the basal and mid-trunk sections of trees.A total of 2925 adults belonging to 239 saproxylic beetle species were captured,of which 56 species are on the IUCN Red List.The results show that declining stands were richer in saproxylic species,and that the diversity of beetle species was greater in these stands.Approximately 1.4 times more species were caught within declining stands than in healthy ones(1.6 times for Red List species).Declining stands hosted more pest species(e.g.,cambiophagous and xylophagous species).However,only low numbers of these species were recorded in these stands.In summary,results of this study suggest that decline of managed oak stands is creating a wide spectrum of habitats for many saproxylic species.Thus,salvage logging of declining oak trees can represent a natural trap and reduce local beetle biodiversity,mainly for saproxylic,endangered or low-mobility species that would be attracted by new suitable habitats.
基金funded by grants EVA4.0 No.Z.02.1.01/0.0/0.0/16_019/0000803 and ITMS2014+313011W580s provided by EU OP RDEin CZ and SKprojects APVV-18-0086,APVV-19-0387,APVV-20-0168,APVV-20-0215 and APVV-22-0056 from the Slovak Research and Development Agencysupport from the European Research Executive Agency for ReForest,Grant Agreement Nr:101060635
文摘While numerous allometric models exist for estimating biomass in trees with single stems,models for multi-stemmed species are scarce.This study presents models for predicting aboveground biomass(AGB)in European hazel(Corylus avellana L.),growing in multi-stemmed shrub form.We measured the size and harvested the biomass of 30 European hazel shrubs,drying and weighing their woody parts and leaves separately.AGB(dry mass)and leaf area models were established using a range of predictors,such as the upper height of the shrub,number of shoots per shrub,canopy projection area,stem base diameter of the thickest stem,and the sum of cross-sectional areas of all stems at the stem base.The latter was the best predictor of AGB,but the most practically useful variables,defined as relatively easy to measure by terrestrial or aerial approaches,were the upper height of the shrub and the canopy projection area.The leaf biomass to AGB ratio decreased with the shrub's height.Specific leaf area of shaded leaves increases with shrub height,but that of leaves at the top of the canopy does not change significantly.Given that the upper shrub height and crown projection of European hazel can be estimated using remote sensing approaches,especially UAV and LIDAR,these two variables appear the most promising for effective measurement of AGB in hazel.
基金supported by the Shenzhen Key Laboratory of Neuroimmunomodulation for Neurological Diseases(ZDSYS20220304163558001).
文摘A recent publication by Zhou et al.[1]in Neuron demonstrates that a specific interaction between astrocytes and a subtype of neurons has an influence on complex animal behavior,namely risk assessment.The majority of neuroscientists analyzing the molecular and cellular substrate of behavior focus on neuronal circuits.Glial cells were originally described by Rudolf Virchow and the name glia refers to the Greek word for glue or putty.Thus,glial cells were long thought to represent simply the filling stuff of the brain.This view has changed dramatically in the last decades.The three major types of glial cells of the central nervous system fulfll diverse functions.Oligodendrocytes are the myelinforming cells and it has become evident that they are plastic and are able to influence neuronal connectivity.Microglia are the immune cells of the brain and interact with synapses during development,in plasticity,and very prominently in any disease of the nervous system.
文摘Propofol(2,6-di-isopropylphenol) is a short-acting,intravenous sedative drug.^([1,2]) The pharmacologic mechanism of propofol is related to its agonistic effects on the gamma-amino butyric acid receptor.^([1-3]) Propofol injection pain(PIP) is well-known in the operating room and is commonly countered by the prophylactic administration of lidocaine.In anesthesia,PIP is encountered in 28%–90% of patients.^([4,5]) However,PIPprophylaxis does not seem to be efficacious in every population.^([6,7]) Whether procedural sedation and analgesia(PSA) in the emergency department(ED) warrants lidocaine administration is unclear.
基金partially supported by the Natural Science Foundation of China under Grant Nos.12175222,11535011,and 11775210support from Deutsche Forschungsgemeinschaft(DFG)under Grant No.531128043also under Grant Nos.397107022,397067869 and 397082825,within the DFG Research Unit FOR 2692,under Grant No.355031190。
文摘In this paper,we investigate the distinctions between dynamical quantum chaotic systems and random models from the perspective of observable properties,particularly focusing on the eigenstate thermalization hypothesis(ETH).Through numerical simulations,we find that for dynamical systems,the envelope function of off-diagonal elements of observables exhibits an exponential decay at largeΔE,while for randomized models,it tends to be flat.We demonstrate that the correlations of chaotic eigenstates,originating from the delicate structures of Hamiltonians,play a crucial role in the non-trivial structure of the envelope function.Furthermore,we analyze the numerical results from the perspective of the dynamical group elements in Hamiltonians.Our findings highlight the importance of correlations in physical chaotic systems and provide insights into the deviations from random matrix theory(RMT)predictions.These understandings offer valuable directions for future research.
基金supported by the University of Eastern FinlandCzech University of Life Sciences doctoral research funding to O.A+5 种基金North Karelia Regional Fund to O.A (grant number 55232028)University of Eastern Finland(strategic fundingproject 931060)the Academy of Finland(C-NEUT,project number 347862)part of the Academy of Finland Flagship on Photonics Research and Innovation (PREIN) decision (320166)the Finnish National Plant Phenotyping Infrastructure (NaPPI/Biocenter Finland)
文摘We used fast chlorophyll fluorescence transients(OJIP) to study provenance-related differences in photosynthetic performance and the magnitude of day-to-day chlorophyll fluorescence(ChlF) variation in northern(67°N)and southern(62°N) silver birches in a common garden at62°N.ChlF transients were measured five times during two weeks in the middle of summer to avoid seasonal variation.Differences in growth and leaf morphological traits between the provenances were also examined.The northern trees had higher chlorophyll content,larger leaf areas,and higher leaf fresh and dry mass than the southern trees,but the leaf mass per area did not differ between the provenances.The southern trees were taller and showed higher annual shoot growth than the northern trees.For all the ChlF parameters,day-to-day variation was significant and followed the same pattern for both provenances with no significant provenance ×day interaction,suggesting a similar response to environmental variation.The northern provenance had higher values in parameters related to the reduction of end electron acceptors at the Photosystem I(PSI) acceptor side as probed by ChlF.This and higher values for performance indices PI_(abs) and PI_(tot) in northern than in southern trees suggest higher photosynthetic performance of northern trees in line with the latitudinal compensation strategy.Provenance differences in these parameters increased towards the end of the measurement period,suggesting preparation for earlier growth cessation in northern trees triggered by the shortening day length.The study shows that provenance differences in ChlF can be relatively stable regardless of environmental variation but might be influenced by physiological alterations in preparation for future changes in environmental conditions.
基金We express our gratitude to the Internal Grant Agency of the Faculty of Forestry and Wood Sciences,Czech University of Life Sciences,Prague(Grant No.IGA A_24_24)the Ministry of Education,Youth and Sports of the Czech Republic(Grant INTER-TRANSFER No.LTT20017)for funding this study.
文摘Understanding the ecological processes shaping competitive interactions among forest trees is crucial for predicting ecosystem productivity and climate change resilience.However,few studies have investigated how the biological attributes of tropical species may affect competitive outcomes under varying resource conditions.We collected and analysed a 10-year dataset of radial growth rates in canopy trees from a network of forest inventory plots located in divergent forest types over an extensive meteorological gradient in Ghana,West Africa.We used nonlinear models to estimate the relative reduction in potential growth(basal area increment)of individual target trees of a given species as a consequence of the combined effects of(1)target tree size,(2)variation in crowding levels by neighbouring trees,(3)the functional attributes of those neighbours(wood density and shade tolerance),and(4)local soil moisture levels.Analyses were conducted separately for the 15 most common species in the inventory network.In opposition to neutral theory,our findings indicate that the strength of interactions among competing species was distinctly asymmetric and dynamic.Wood density was an important characteristic that modified competitive outcomes for most species,particularly under varying levels of resource availability.Specifically,dense wood was an attribute that conferred comparatively stronger competitive ability in moisture-limited conditions.Larger individuals were notably less sensitive to the effects of moisture-dependent competition.Our results suggest that attributes such as wood density may reflect divergent life history strategies that differentiate species’fitness and competitive ability in varying environments.The dynamic nature of competition,influenced by a complex interplay of biological and abiotic factors,implies that more prevalent dry periods,which have been forecast for tropical Africa,may impact the physiognomy and function of future forest communities in the region.
文摘Sessile oak(Quercus petraea(Matt.)Liebl.)is widely distributed across most of Europe particularly the hills and lower mountain ranges,so is considered“the oak of the mountains”.This species grows on a wide variety of soils and at altitudes ranging from sea level to 2200 m,especially in Atlantic and sub-Mediterranean climates,and it is sensitive to low winter temperatures,early and late frosts,as well as high summer temperatures.Sessile oak forms both pure and mixed stands especially with broadleaves such as European beech,European hornbeam,small-leaved lime and Acer spp.These form the understorey of sessile oak stands,promoting the natural shedding of lower branches of the oak and protecting the trunk against epicormic branches.Sessile oak is a long-lived,light-demanding and wind-firm species,owing to its taproot and heart-shaped root system.Its timber,one of the most valuable in Europe,is important for fur-niture-making(both solid wood and veneer),construction,barrels,railway sleepers,and is also used as fuelwood.It is one of the few major tree species in Europe that is regener-ated by seed(naturally or artificially)and by stump shoots in high forest,coppice-with-standards and coppice forests.Sessile oak forests are treated in both regular and irregular systems involving silvicultural techniques such as uniform shelterwood,group shelterwood,irregular shelterwood,irregular high forest,coppice-with-standards and simple coppice.Young naturally regenerated stands are managed by weeding,release cutting and cleaning-respacing,keeping the stands quite dense for good natural pruning.Plantations are based on(1)2-4-year old bare-root or container-grown seedlings produced in nurseries using seeds from genetic resources,seed stands and seed orchards.The density of sessile oak plantations(mostly in rows,but also in clusters)is usually between 4000 and 6000 ind.ha^(−1).Sessile oak silviculture of mature stands includes crown thinning,focus-ing on final crop trees(usually a maximum of 100 ind.ha^(−1))and targeting the production of large-diameter and high quality trees at long rotation ages(mostly over 120 years,sometimes 250-300 years).In different parts of Europe,conversion of simple coppices and coppice-with-standards to high forests is continuing.Even though manage-ment of sessile oak forests is very intensive and expensive,requiring active human intervention,the importance of this species in future European forests will increase in the con-text of climate change due to its high resistance to distur-bance,superior drought tolerance and heat stress resistance.
基金the National Social Science Foundation of China(19ZDA361)。
文摘How to quickly predict an individual’s behavioral choices is an important issue in the field of human behavior research.Using noninvasive electroencephalography,we aimed to identify neural markers in the prior outcome-evaluation stage and the current option-assessment stage of the chicken game that predict an individual’s behavioral choices in the subsequent decision-output stage.Hierarchical linear modeling-based brain-behavior association analyses revealed that midfrontal theta oscillation in the prior outcome-evaluation stage positively predicted subsequent aggressive choices;also,beta oscillation in the current option-assessment stage positively predicted subsequent cooperative choices.These findings provide electrophysiological evidence for the three-stage theory of decision-making and strengthen the feasibility of predicting an individual’s behavioral choices using neural oscillations.
