Continuous flow intersections (CFIs), also known as displaced left turns (DLTs), are a type of alternative intersection designed to improve operations at locations with heavy left-turn movements by reallocating these ...Continuous flow intersections (CFIs), also known as displaced left turns (DLTs), are a type of alternative intersection designed to improve operations at locations with heavy left-turn movements by reallocating these vehicles to the left side of opposing traffic. Currently, simulation is commonly used to evaluate operational performance of CFIs. However, this approach requires significant on-site data collection and is highly dependent on the analyst’s ability to correctly model the intersection and driver behavior. Recently, connected vehicle (CV) trajectory data has become widely available and presents opportunities for the direct measurement of traffic signal performance measures. This study utilizes CV trajectory data to analyze the performance of a CFI located in West Valley City, UT. Over 4500 trajectories and 105,000 GPS points are analyzed from August 2021 weekday data. Trajectories are linear-referenced to generate Purdue Probe Diagrams (PPDs) and extended PPDs to estimate split failures (SF), arrivals on green (AOG), traditional Highway Capacity Manual (HCM) level of service (LOS), and the distribution of stops. The estimated operational performance showed effective progression during the PM peak period at all the critical internal storage areas with AOG levels at exit traffic signals between 83% and 100%. In contrast, all external approaches with longer queue storage areas had AOG values ranging from 2% to 81% during the same time period. The presented analytical techniques and summary graphics provide practitioners with tools to evaluate the performance of any CFI where CV trajectories are available without the need for on-site data collection.展开更多
To gain insight into the genetic regulation of lipid metabolism in tomato, we conducted metabolic trait loci （mQTL） analysis following the lipidomic profiling of fruit pericarp and leaf tissue of the Solanum pennell...To gain insight into the genetic regulation of lipid metabolism in tomato, we conducted metabolic trait loci （mQTL） analysis following the lipidomic profiling of fruit pericarp and leaf tissue of the Solanum pennellii introgression lines （IL）. To enhance mapping resolution for selected fruit-specific mQTL, we profiled the lipids in a subset of independently derived S. pennellii backcross inbred lines, as well as in a nearsogenic sub-iL population. We identified a putative lecithin：cholesterol acyltransferase that controls the levels of several lipids, and two members of the class III lipase family, LIP1 and LIP2, that were associated with decreased levels of diacylglycerols （DAGs） and triacylglycerols （TAGs）. Lipases of this class cleave fatty acids from the glycerol backbone of acylglycerols. The released fatty acids serve as precursors of flavor volatiles. We show that LIP1 expression correlates with fatty acid-derived volatile levels. We further confirm the function of LIP1 in TAG and DAG breakdown and volatile synthesis using transgenic plants. Taken together, our study extensively characterized the genetic architecture of Upophilic compounds in tomato and demonstrated at molecular level that release of free fatty acids from the glycerol backbone can have a major impact on downstream volatile synthesis.展开更多
文摘Continuous flow intersections (CFIs), also known as displaced left turns (DLTs), are a type of alternative intersection designed to improve operations at locations with heavy left-turn movements by reallocating these vehicles to the left side of opposing traffic. Currently, simulation is commonly used to evaluate operational performance of CFIs. However, this approach requires significant on-site data collection and is highly dependent on the analyst’s ability to correctly model the intersection and driver behavior. Recently, connected vehicle (CV) trajectory data has become widely available and presents opportunities for the direct measurement of traffic signal performance measures. This study utilizes CV trajectory data to analyze the performance of a CFI located in West Valley City, UT. Over 4500 trajectories and 105,000 GPS points are analyzed from August 2021 weekday data. Trajectories are linear-referenced to generate Purdue Probe Diagrams (PPDs) and extended PPDs to estimate split failures (SF), arrivals on green (AOG), traditional Highway Capacity Manual (HCM) level of service (LOS), and the distribution of stops. The estimated operational performance showed effective progression during the PM peak period at all the critical internal storage areas with AOG levels at exit traffic signals between 83% and 100%. In contrast, all external approaches with longer queue storage areas had AOG values ranging from 2% to 81% during the same time period. The presented analytical techniques and summary graphics provide practitioners with tools to evaluate the performance of any CFI where CV trajectories are available without the need for on-site data collection.
基金Part of this work was also supported by a grant from the National Science Foundation （IOS-0923312） to H.K.S.A. and A.R.F. acknowledge funding of the PlantaSYST project by the European Union＇s Horizon 2020 research and innovation program （SGA-CSA nos. 664621 and 739582 under FPA no. 664620）. D.Z. was funded by a TOMRES grant （142020 #727929）.
文摘To gain insight into the genetic regulation of lipid metabolism in tomato, we conducted metabolic trait loci （mQTL） analysis following the lipidomic profiling of fruit pericarp and leaf tissue of the Solanum pennellii introgression lines （IL）. To enhance mapping resolution for selected fruit-specific mQTL, we profiled the lipids in a subset of independently derived S. pennellii backcross inbred lines, as well as in a nearsogenic sub-iL population. We identified a putative lecithin：cholesterol acyltransferase that controls the levels of several lipids, and two members of the class III lipase family, LIP1 and LIP2, that were associated with decreased levels of diacylglycerols （DAGs） and triacylglycerols （TAGs）. Lipases of this class cleave fatty acids from the glycerol backbone of acylglycerols. The released fatty acids serve as precursors of flavor volatiles. We show that LIP1 expression correlates with fatty acid-derived volatile levels. We further confirm the function of LIP1 in TAG and DAG breakdown and volatile synthesis using transgenic plants. Taken together, our study extensively characterized the genetic architecture of Upophilic compounds in tomato and demonstrated at molecular level that release of free fatty acids from the glycerol backbone can have a major impact on downstream volatile synthesis.
