The mechanisms of seismically-induced liquefaction of granular soils underhigh confining stresses are still not fully understood.Evaluation of these mechanisms is generallybased on extrapolation of observed behavior a...The mechanisms of seismically-induced liquefaction of granular soils underhigh confining stresses are still not fully understood.Evaluation of these mechanisms is generallybased on extrapolation of observed behavior at shallow depths.Three centrifuge model tests wereconducted at RPI's experimental facility to investigate the effects of confining stresses on thedynamic response of a deep horizontal deposit of saturated sand.Liquefaction was observed at highconfining stresses in each of the tests.A system identification procedure was used to estimate theassociated shear strain and stress time histories.These histories revealed a response marked byshear strength degradation and dilative patterns.The recorded accelerations and pore pressures wereemployed to generate visual animations of the models.These visualizations revealed a liquefactionfront traveling downward and leading to large shear strains and isolation of upper soil layers.展开更多
This article presents a finite element analysis of reinforced concrete deep beams using nonlinear fracture mechanics. The article describes the development of a numerical model that includes several nonlinear processe...This article presents a finite element analysis of reinforced concrete deep beams using nonlinear fracture mechanics. The article describes the development of a numerical model that includes several nonlinear processes such as compression and tension softening of concrete, bond slip between concrete and reinforcement, and the yielding of the longitudinal steel reinforcement. The development also incorporates the Delaunay refinement algorithm to create a triangular topology that is then transformed into a quadrilateral mesh by the quad-morphing algorithm. These two techniques allow automatic remeshing using the discrete crack approach. Nonlinear fracture mechanics is incorporated using the fictitious crack model and the principal tensile strength for crack initiation and propagation. The model has been successful in reproducing the load deflections, cracking patterns and size effects observed in experiments of normal and high-strength concrete deep beams with and without stirrup reinforcement.展开更多
Electroosmotic water vapor transport (WVT) across very thin, flexible, functionalized conducting polymer (CP) microporous (μP) membranes at a very high rate is reported. Both passive and active (6 VDC applied) WVT ar...Electroosmotic water vapor transport (WVT) across very thin, flexible, functionalized conducting polymer (CP) microporous (μP) membranes at a very high rate is reported. Both passive and active (6 VDC applied) WVT are reported, the latter for the first time ever. WVT occurs with concomitant, effective blocking of chemical warfare (CW) agents, again demonstrated for the first time ever. Initial active liquid||membrane||liquid interface studies demonstrated WVT rates of >1.7 × 10-5g .mm-2s-1, >3 × the highest prior reported values of 5 × 10-6g.mm-2s-1. Subsequent vapor||membrane|| vapor interface studies using industry-standard methods (including ASTM E96B Upright Cup (“WVT”), ASTM F2298 (“Dynamic Moisture Permeation Cell”) and ASTM F1868 (“Sweating Guard Hotplate”) were done at independent, external labs for independent corroboration. These yielded, e.g., WVT values of2564.4 g.m2.d-1 (passive) and3706.7 g.m2d-1 (active), to be compared with the highest (passive) value ever reported previously,984.8 g.m2.d-1 for a μP-Nylon membrane. More than 15 different membrane configurations, porosities and types were studied, including membranes with CP + organophosphate hydrolase (OPH), an enzyme reactive to CW agents. Efficient blocking of the actual CW agents GB, HD, VX is also reported, using the TOP-8-2-501standard. Membranes also passed all Industry-standard durability tests, e.g. ASTM D2261 (Tearing), ASTM D5034 (Breaking), ASTM D3886 (Abrasion), ASTM F392 (Gelbo Flex). Incorporation into smart soldiers’ garments was demonstrated;power consumption was -2. Mechanisms of enhanced WVT and CW agent blocking in the membranes are discussed.展开更多
In recent years, a significant number of environmental studies have been conducted in New Orleans, LA and surrounding Gulf Coast areas due in part to the occurrence of hurricanes Katrina and Rita. Data collected from ...In recent years, a significant number of environmental studies have been conducted in New Orleans, LA and surrounding Gulf Coast areas due in part to the occurrence of hurricanes Katrina and Rita. Data collected from studies in the New Orleans area indicate that inorganic contaminants including arsenic (As), iron (Fe), lead (Pb), and vanadium (V);high concentration of bioaerosols, particularly Cladosporium and Aspergillus, and several organic pollutants (PAHs, pesticides, and volatiles) may pose a risk to human health in New Orleans. While many of these results resemble historical data, a current quantitative exposure assessment has not been conducted. We engaged in one such assessment for lead (Pb) contamination in surface soils. We used Pb concentrations in surface soils ( μg/day to 102 μg/day for our study area within urbanNew Orleans. These data are concerning because children exposed to >33.5 μg/d Pb may cause their blood-Pb levels to exceed the Centers for Disease Control and Prevention (CDC) threshold for blood-Pb of 10 μg/dL. It has generally been accepted that a more protective blood Pb concentration threshold of 6 - μg/dL is warranted. Using the 6-μg/dL threshold puts children exposed to as little as 20.2 μg/day Pb at risk.展开更多
The concepts of business continuity management,operational resilience,and organizational resilience each refer to actions that businesses and organizations can take in anticipating and responding to disruptions.Howeve...The concepts of business continuity management,operational resilience,and organizational resilience each refer to actions that businesses and organizations can take in anticipating and responding to disruptions.However,the existing definitions and usages are difficult to differentiate due to overlapping objectives,implementation processes,and outcomes.This article examines definitions and approaches for these three concepts and suggest a framework to operationalize methods and tools relevant to each.These definitions emphasize three dyads:risk versus resilience;organizational processes versus assets;and normal operating conditions versus crisis conditions.Using these dyads to differentiate the concepts of business continuity management,operational resilience,and organizational resilience can support planners in clarifying objectives and identifying which approach will be most beneficial as businesses or organizations plan for and encounter disruptions.This article evaluates these concepts by examining illustrative examples of disruptions and responses.展开更多
Maintaining beneficial, native plant structure and diversity while reducing invasive, nuisance species dominance is an important management domain for natural resource managers. One such vegetation component in North ...Maintaining beneficial, native plant structure and diversity while reducing invasive, nuisance species dominance is an important management domain for natural resource managers. One such vegetation component in North American lakes and reservoirs is submerged aquatic vegetation—a valuable aquatic resource which serves as productive habitat for fish, aquatic macroinvertebrates, and other wildlife. Reservoirs in the southern parts of the United States have experienced varying aquatic plant dominance dynamics due to historical water resource management actions, including drawdowns and introduction of herbivorous fish for the purpose of controlling invasive aquatic vegetation. Some of these management options have also been detrimental to native submerged aquatic vegetation. This paper explores an adaptive management research effort by installing herbivore-protected, fenced-pen submerged aquatic vegetation sites in a high-herbivore reservoir to determine effectiveness of protecting habitat and serving as founder colony sources for propagule spread. Four experimental sites with three management treatments each were planted with American eelgrass. Each site utilized one un-fenced treatment and two treatments with varying mesh sizes for protective fencing-pens. Site integrity, species survival and spread, and grazing were documented. One additional site was installed and planted with other native submerged aquatic vegetation species for nominal species performance descriptions. No plants survived unprotected in the high-herbivore system and plants, in general, performed consistently better within the smaller mesh size. These test planting results were ultimately used to inform adaptive management decision making for plant installation and expansion designs for managing reservoirs invested with Hydrilla, considered one of the most serious invasive aquatic plants in the United States.展开更多
Research has been continually growing toward the development of image-based structural health monitoring tools that can leverage deep learning models to automate damage detection in civil infrastructure.However,these ...Research has been continually growing toward the development of image-based structural health monitoring tools that can leverage deep learning models to automate damage detection in civil infrastructure.However,these tools are typically based on RGB images,which work well under ideal lighting conditions,but often have degrading performance in poor and low-light scenes.On the other hand,thermal images,while lacking in crispness of details,do not show the same degradation of performance in changing lighting conditions.The potential to enhance automated damage detection by fusing RGB and thermal images together within a deep learning network has yet to be explored.In this paper,RGB and thermal images are fused in a ResNET-based semantic segmentation model for vision-based inspections.A convolutional neural network is then employed to automatically identify damage defects in concrete.The model uses a thermal and RGB encoder to combine the features detected from both spectrums to improve its performance of the model,and a single decoder to predict the classes.The results suggest that this RGB-thermal fusion network outperforms the RGB-only network in the detection of cracks using the Intersection Over Union(IOU)performance metric.The RGB-thermal fusion model not only detected damage at a higher performance rate,but it also performed much better in differentiating the types of damage.展开更多
Artificial intelligence(AI)applications are growing in medicine.It is important to understand the current state of the AI applications prior to utilizing in disease research and treatment.In this review,AI application...Artificial intelligence(AI)applications are growing in medicine.It is important to understand the current state of the AI applications prior to utilizing in disease research and treatment.In this review,AI application in the diagnosis and treatment of gastrointestinal diseases are studied and summarized.In most cases,AI studies had large amounts of data,including images,to learn to distinguish disease characteristics according to a human’s perspectives.The detailed pros and cons of utilizing AI approaches should be investigated in advance to ensure the safe application of AI in medicine.Evidence suggests that the collaborative usage of AI in both diagnosis and treatment of diseases will increase the precision and effectiveness of medicine.Recent progress in genome technology such as genome editing provides a specific example where AI has revealed the diagnostic and therapeutic possibilities of RNA detection and targeting.展开更多
Plants respond to slight increases in ambient temperature by altering their architecture,a phenomenon collectively termed thermomorphogenesis.Thermomorphogenesis helps mitigate the damage caused by potentially harmful...Plants respond to slight increases in ambient temperature by altering their architecture,a phenomenon collectively termed thermomorphogenesis.Thermomorphogenesis helps mitigate the damage caused by potentially harmful high-temperature conditions and is modulated by multiple environmental factors.Among these factors,ultraviolet-B(UV-B)light has been shown to strongly suppress this response.However,the molecular mechanisms by which UV-B light regulates thermomorphogenesis and the physiological roles of the UV-B-mediated suppression remain poorly understood.Here,we show that UV-B light inhibits thermomorphogenesis through the UV RESISTANCE LOCUS8(UVR8)–CONSTITUTIVE PHOTOMORPHOGENIC1(COP1)–phytochrome B(phyB)/LONG HYPOCOTYL IN FAR RED 1(HFR1)signaling pathway.We found that cop1 mutants maintain high levels of active phyB at high temperatures.Extensive genetic analyses revealed that the increased levels of phyB,HFR1,and CRY1 in cop1 mutants redundantly reduce both the level and the activity of PHYTOCHROME INTERACTING FACTOR4(PIF4),a key positive regulator in thermomorphogenesis,thereby repressing this growth response.In addition,we found that UV-B light inactivates COP1 to enhance phyB stability and increase its photobody number.The UV-B-stabilized active phyB,in concert with HFR1,inhibits thermomorphogenesis by interfering with PIF4 activity.We further demonstrate that increased levels of active phyB enhance UV-B tolerance by promoting flavonoid biosynthesis and inhibiting thermomorphogenic growth.Taken together,our results elucidate that UV-B increases the levels of active phyB and HFR1 by inhibiting COP1 to suppress PIF4-mediated growth responses,which is crucial for plant tolerance to UV-B stress at high temperatures.展开更多
This paper presents 2D wave-current interaction model for evaluating nearly horizontal wave-induced currents in the surf-zone and coastal waters.The hydrodynamic model is the two-dimensional depth-averaged nonlinear s...This paper presents 2D wave-current interaction model for evaluating nearly horizontal wave-induced currents in the surf-zone and coastal waters.The hydrodynamic model is the two-dimensional depth-averaged nonlinear shallow water equations by using an unstructured non-staggered and multiple-level quadtree rectangular mesh,this mesh information is stored in simple data structures and it is easy to obtain a locally high resolution for important region.The intercell fluxes are computed based on the HLL(Harten-Lax-van Leer) approximate Riemann solver with shock capturing capability for computing the dry-to-wet interface of coastal line.The effects of pressure and gravity are included in source term in the model,this treatment can simplify the computation and eliminate numerical imbalance between source and flux terms.The wave model readily provides the radiation stresses that represent the shortwave-averaged forces in a water column for the hydrodynamic model and the wave model takes into account the effect of wave-induced nearshore currents and water level.The coupling model is applied to verify different experimental cases and real life case of considering the wave-current interaction.The calculated results agree with analytical solution,experimental and field data.The results show that the modeling approach presented herein should be useful in simulating the nearshore processes in complicated natural coastal domains.展开更多
Wind-wave steepness along the North Atlantic(27.46 N<lat<43.53 N and 62.03 W<lon<80.19 W)is characterized based on at most 37 years(1984 to 2020)of buoy measurements.Wave data from 16 National Data Buoy Ce...Wind-wave steepness along the North Atlantic(27.46 N<lat<43.53 N and 62.03 W<lon<80.19 W)is characterized based on at most 37 years(1984 to 2020)of buoy measurements.Wave data from 16 National Data Buoy Center(NDBC)and 2 Marine Environmental Data Section(MEDS)stations located at depths ranging from 33 m to 5394 m are used.Intra-annual variability of the full spectrum wave steepness(s_(m))and the wind-sea steepness(s_(mw))are analyzed.Among the 18 locations,the average sm and smw ranged between 0.023 to 0.037 and 0.025 to 0.039,respectively.Results show similar intra-annual variability among the different buoys both for sm and for smw with monthly average maximums occurring between January and February(0.029<s_(m)<0.045,0.030<s_(mw)<0.048)and minimums between July and August(0.018<s_(m)<0.033,0.019<s_(mw)<0.035).The probability distribution function of sm/smw presents a peak between 0.9 and 1.0 for all stations.It is also found that the sea states with the maximum sm and smw are not directly linked to the maximum events of significant wave height.Practically,these findings can inform the implementation of various ocean engineering endeavors as well as navigation risk determination,as wave steepness exerts a significant influence on several physical processes in the marine environment.展开更多
This article develops a novel decision-oriented framework that strategically deconstructs systems resilience in a way that focuses on systems'design,capabilities,and management.The framework helps evaluate and com...This article develops a novel decision-oriented framework that strategically deconstructs systems resilience in a way that focuses on systems'design,capabilities,and management.The framework helps evaluate and compare how system design choices impact system resilience.First,we propose a resilience score based on a piecewise linear approximation to a resilience curve.Using multicriteria decision analysis principles,we score system design alternatives in terms of system-specific capabilities.We estimate the relevance of these capabilities to resilience curve parameters associated with resilience phases.Finally,we interpret the derivatives of resilience with respect to the curve parameter values as the leverage of these parameters.Using multiple levels of weighted sums of the scores,we calculate the first order impact of system design choices first on a proxy for the generic resilience parameters and then on resilience,which allows situational characteristics to be incorporated in their natural terminology while mapping their impact on resilience with a traceable logic.We illustrate the approach by using existing materials to develop an example comparing engineered designs for minimizing post-wildfire flood impacts.展开更多
基金This research was supported by the National Science Foundation,Grant No.CMS-984754(Dr.C.Astill program manager)the US Army Engineer Research and Development Center.
文摘The mechanisms of seismically-induced liquefaction of granular soils underhigh confining stresses are still not fully understood.Evaluation of these mechanisms is generallybased on extrapolation of observed behavior at shallow depths.Three centrifuge model tests wereconducted at RPI's experimental facility to investigate the effects of confining stresses on thedynamic response of a deep horizontal deposit of saturated sand.Liquefaction was observed at highconfining stresses in each of the tests.A system identification procedure was used to estimate theassociated shear strain and stress time histories.These histories revealed a response marked byshear strength degradation and dilative patterns.The recorded accelerations and pore pressures wereemployed to generate visual animations of the models.These visualizations revealed a liquefactionfront traveling downward and leading to large shear strains and isolation of upper soil layers.
文摘This article presents a finite element analysis of reinforced concrete deep beams using nonlinear fracture mechanics. The article describes the development of a numerical model that includes several nonlinear processes such as compression and tension softening of concrete, bond slip between concrete and reinforcement, and the yielding of the longitudinal steel reinforcement. The development also incorporates the Delaunay refinement algorithm to create a triangular topology that is then transformed into a quadrilateral mesh by the quad-morphing algorithm. These two techniques allow automatic remeshing using the discrete crack approach. Nonlinear fracture mechanics is incorporated using the fictitious crack model and the principal tensile strength for crack initiation and propagation. The model has been successful in reproducing the load deflections, cracking patterns and size effects observed in experiments of normal and high-strength concrete deep beams with and without stirrup reinforcement.
文摘Electroosmotic water vapor transport (WVT) across very thin, flexible, functionalized conducting polymer (CP) microporous (μP) membranes at a very high rate is reported. Both passive and active (6 VDC applied) WVT are reported, the latter for the first time ever. WVT occurs with concomitant, effective blocking of chemical warfare (CW) agents, again demonstrated for the first time ever. Initial active liquid||membrane||liquid interface studies demonstrated WVT rates of >1.7 × 10-5g .mm-2s-1, >3 × the highest prior reported values of 5 × 10-6g.mm-2s-1. Subsequent vapor||membrane|| vapor interface studies using industry-standard methods (including ASTM E96B Upright Cup (“WVT”), ASTM F2298 (“Dynamic Moisture Permeation Cell”) and ASTM F1868 (“Sweating Guard Hotplate”) were done at independent, external labs for independent corroboration. These yielded, e.g., WVT values of2564.4 g.m2.d-1 (passive) and3706.7 g.m2d-1 (active), to be compared with the highest (passive) value ever reported previously,984.8 g.m2.d-1 for a μP-Nylon membrane. More than 15 different membrane configurations, porosities and types were studied, including membranes with CP + organophosphate hydrolase (OPH), an enzyme reactive to CW agents. Efficient blocking of the actual CW agents GB, HD, VX is also reported, using the TOP-8-2-501standard. Membranes also passed all Industry-standard durability tests, e.g. ASTM D2261 (Tearing), ASTM D5034 (Breaking), ASTM D3886 (Abrasion), ASTM F392 (Gelbo Flex). Incorporation into smart soldiers’ garments was demonstrated;power consumption was -2. Mechanisms of enhanced WVT and CW agent blocking in the membranes are discussed.
文摘In recent years, a significant number of environmental studies have been conducted in New Orleans, LA and surrounding Gulf Coast areas due in part to the occurrence of hurricanes Katrina and Rita. Data collected from studies in the New Orleans area indicate that inorganic contaminants including arsenic (As), iron (Fe), lead (Pb), and vanadium (V);high concentration of bioaerosols, particularly Cladosporium and Aspergillus, and several organic pollutants (PAHs, pesticides, and volatiles) may pose a risk to human health in New Orleans. While many of these results resemble historical data, a current quantitative exposure assessment has not been conducted. We engaged in one such assessment for lead (Pb) contamination in surface soils. We used Pb concentrations in surface soils ( μg/day to 102 μg/day for our study area within urbanNew Orleans. These data are concerning because children exposed to >33.5 μg/d Pb may cause their blood-Pb levels to exceed the Centers for Disease Control and Prevention (CDC) threshold for blood-Pb of 10 μg/dL. It has generally been accepted that a more protective blood Pb concentration threshold of 6 - μg/dL is warranted. Using the 6-μg/dL threshold puts children exposed to as little as 20.2 μg/day Pb at risk.
基金funded in part by the US Army Engineer Research and Development Center(FLEX-4).
文摘The concepts of business continuity management,operational resilience,and organizational resilience each refer to actions that businesses and organizations can take in anticipating and responding to disruptions.However,the existing definitions and usages are difficult to differentiate due to overlapping objectives,implementation processes,and outcomes.This article examines definitions and approaches for these three concepts and suggest a framework to operationalize methods and tools relevant to each.These definitions emphasize three dyads:risk versus resilience;organizational processes versus assets;and normal operating conditions versus crisis conditions.Using these dyads to differentiate the concepts of business continuity management,operational resilience,and organizational resilience can support planners in clarifying objectives and identifying which approach will be most beneficial as businesses or organizations plan for and encounter disruptions.This article evaluates these concepts by examining illustrative examples of disruptions and responses.
文摘Maintaining beneficial, native plant structure and diversity while reducing invasive, nuisance species dominance is an important management domain for natural resource managers. One such vegetation component in North American lakes and reservoirs is submerged aquatic vegetation—a valuable aquatic resource which serves as productive habitat for fish, aquatic macroinvertebrates, and other wildlife. Reservoirs in the southern parts of the United States have experienced varying aquatic plant dominance dynamics due to historical water resource management actions, including drawdowns and introduction of herbivorous fish for the purpose of controlling invasive aquatic vegetation. Some of these management options have also been detrimental to native submerged aquatic vegetation. This paper explores an adaptive management research effort by installing herbivore-protected, fenced-pen submerged aquatic vegetation sites in a high-herbivore reservoir to determine effectiveness of protecting habitat and serving as founder colony sources for propagule spread. Four experimental sites with three management treatments each were planted with American eelgrass. Each site utilized one un-fenced treatment and two treatments with varying mesh sizes for protective fencing-pens. Site integrity, species survival and spread, and grazing were documented. One additional site was installed and planted with other native submerged aquatic vegetation species for nominal species performance descriptions. No plants survived unprotected in the high-herbivore system and plants, in general, performed consistently better within the smaller mesh size. These test planting results were ultimately used to inform adaptive management decision making for plant installation and expansion designs for managing reservoirs invested with Hydrilla, considered one of the most serious invasive aquatic plants in the United States.
文摘Research has been continually growing toward the development of image-based structural health monitoring tools that can leverage deep learning models to automate damage detection in civil infrastructure.However,these tools are typically based on RGB images,which work well under ideal lighting conditions,but often have degrading performance in poor and low-light scenes.On the other hand,thermal images,while lacking in crispness of details,do not show the same degradation of performance in changing lighting conditions.The potential to enhance automated damage detection by fusing RGB and thermal images together within a deep learning network has yet to be explored.In this paper,RGB and thermal images are fused in a ResNET-based semantic segmentation model for vision-based inspections.A convolutional neural network is then employed to automatically identify damage defects in concrete.The model uses a thermal and RGB encoder to combine the features detected from both spectrums to improve its performance of the model,and a single decoder to predict the classes.The results suggest that this RGB-thermal fusion network outperforms the RGB-only network in the detection of cracks using the Intersection Over Union(IOU)performance metric.The RGB-thermal fusion model not only detected damage at a higher performance rate,but it also performed much better in differentiating the types of damage.
基金Supported by Japan Agency for Medical Research and Development(AMED),No.JP20ak0101093.
文摘Artificial intelligence(AI)applications are growing in medicine.It is important to understand the current state of the AI applications prior to utilizing in disease research and treatment.In this review,AI application in the diagnosis and treatment of gastrointestinal diseases are studied and summarized.In most cases,AI studies had large amounts of data,including images,to learn to distinguish disease characteristics according to a human’s perspectives.The detailed pros and cons of utilizing AI approaches should be investigated in advance to ensure the safe application of AI in medicine.Evidence suggests that the collaborative usage of AI in both diagnosis and treatment of diseases will increase the precision and effectiveness of medicine.Recent progress in genome technology such as genome editing provides a specific example where AI has revealed the diagnostic and therapeutic possibilities of RNA detection and targeting.
基金supported by the National Research Foundation of Korea,funded by the Korean government(NRF-2022R1A4A3024451,NRF-2023R1A2C3002386,NRF-2021R1A6A3A13046676,NRF-2021R1A4A 1032888,and NRF-RS-2024-00461656)support was provided by a grant from Korea University.
文摘Plants respond to slight increases in ambient temperature by altering their architecture,a phenomenon collectively termed thermomorphogenesis.Thermomorphogenesis helps mitigate the damage caused by potentially harmful high-temperature conditions and is modulated by multiple environmental factors.Among these factors,ultraviolet-B(UV-B)light has been shown to strongly suppress this response.However,the molecular mechanisms by which UV-B light regulates thermomorphogenesis and the physiological roles of the UV-B-mediated suppression remain poorly understood.Here,we show that UV-B light inhibits thermomorphogenesis through the UV RESISTANCE LOCUS8(UVR8)–CONSTITUTIVE PHOTOMORPHOGENIC1(COP1)–phytochrome B(phyB)/LONG HYPOCOTYL IN FAR RED 1(HFR1)signaling pathway.We found that cop1 mutants maintain high levels of active phyB at high temperatures.Extensive genetic analyses revealed that the increased levels of phyB,HFR1,and CRY1 in cop1 mutants redundantly reduce both the level and the activity of PHYTOCHROME INTERACTING FACTOR4(PIF4),a key positive regulator in thermomorphogenesis,thereby repressing this growth response.In addition,we found that UV-B light inactivates COP1 to enhance phyB stability and increase its photobody number.The UV-B-stabilized active phyB,in concert with HFR1,inhibits thermomorphogenesis by interfering with PIF4 activity.We further demonstrate that increased levels of active phyB enhance UV-B tolerance by promoting flavonoid biosynthesis and inhibiting thermomorphogenic growth.Taken together,our results elucidate that UV-B increases the levels of active phyB and HFR1 by inhibiting COP1 to suppress PIF4-mediated growth responses,which is crucial for plant tolerance to UV-B stress at high temperatures.
基金supported by the National Natural Science Foundation of China (Grant No. 50839001)the research grant from Southeast Regional Research Initiative (SERRI,80037)the Coastal Inlets Research Program,ERDC,US Army Corps of Engineers,Vicksburg,MS,USA
文摘This paper presents 2D wave-current interaction model for evaluating nearly horizontal wave-induced currents in the surf-zone and coastal waters.The hydrodynamic model is the two-dimensional depth-averaged nonlinear shallow water equations by using an unstructured non-staggered and multiple-level quadtree rectangular mesh,this mesh information is stored in simple data structures and it is easy to obtain a locally high resolution for important region.The intercell fluxes are computed based on the HLL(Harten-Lax-van Leer) approximate Riemann solver with shock capturing capability for computing the dry-to-wet interface of coastal line.The effects of pressure and gravity are included in source term in the model,this treatment can simplify the computation and eliminate numerical imbalance between source and flux terms.The wave model readily provides the radiation stresses that represent the shortwave-averaged forces in a water column for the hydrodynamic model and the wave model takes into account the effect of wave-induced nearshore currents and water level.The coupling model is applied to verify different experimental cases and real life case of considering the wave-current interaction.The calculated results agree with analytical solution,experimental and field data.The results show that the modeling approach presented herein should be useful in simulating the nearshore processes in complicated natural coastal domains.
基金FCT/MCTES for the financial support to CESAM(UIDP/50017/2020+UIDB/50017/2020+LA/P/0094/2020),through national funds.
文摘Wind-wave steepness along the North Atlantic(27.46 N<lat<43.53 N and 62.03 W<lon<80.19 W)is characterized based on at most 37 years(1984 to 2020)of buoy measurements.Wave data from 16 National Data Buoy Center(NDBC)and 2 Marine Environmental Data Section(MEDS)stations located at depths ranging from 33 m to 5394 m are used.Intra-annual variability of the full spectrum wave steepness(s_(m))and the wind-sea steepness(s_(mw))are analyzed.Among the 18 locations,the average sm and smw ranged between 0.023 to 0.037 and 0.025 to 0.039,respectively.Results show similar intra-annual variability among the different buoys both for sm and for smw with monthly average maximums occurring between January and February(0.029<s_(m)<0.045,0.030<s_(mw)<0.048)and minimums between July and August(0.018<s_(m)<0.033,0.019<s_(mw)<0.035).The probability distribution function of sm/smw presents a peak between 0.9 and 1.0 for all stations.It is also found that the sea states with the maximum sm and smw are not directly linked to the maximum events of significant wave height.Practically,these findings can inform the implementation of various ocean engineering endeavors as well as navigation risk determination,as wave steepness exerts a significant influence on several physical processes in the marine environment.
文摘This article develops a novel decision-oriented framework that strategically deconstructs systems resilience in a way that focuses on systems'design,capabilities,and management.The framework helps evaluate and compare how system design choices impact system resilience.First,we propose a resilience score based on a piecewise linear approximation to a resilience curve.Using multicriteria decision analysis principles,we score system design alternatives in terms of system-specific capabilities.We estimate the relevance of these capabilities to resilience curve parameters associated with resilience phases.Finally,we interpret the derivatives of resilience with respect to the curve parameter values as the leverage of these parameters.Using multiple levels of weighted sums of the scores,we calculate the first order impact of system design choices first on a proxy for the generic resilience parameters and then on resilience,which allows situational characteristics to be incorporated in their natural terminology while mapping their impact on resilience with a traceable logic.We illustrate the approach by using existing materials to develop an example comparing engineered designs for minimizing post-wildfire flood impacts.
