A metropolitan city such as Los Angeles (LA) is an ideal study site with a very high population density, and it houses at least 3 treatment plants where sewage is treated preliminarily and then progressing to tertiary...A metropolitan city such as Los Angeles (LA) is an ideal study site with a very high population density, and it houses at least 3 treatment plants where sewage is treated preliminarily and then progressing to tertiary treatment before discharging into the LA River. We will gain a better understanding of the water quality in the LA River and the nitrate load in the watershed system by examining the influence of waste water treatment plants (WWTPs). The goal of this study is to pinpoint the exact source of nitrate in the LA River using the isotope signatures. We have selected sampling locations both upstream and downstream of the WWTP. This serves to monitor nitrate levels, aiding in the assessment of treatment plant effectiveness, pinpointing nitrate pollution sources, and ensuring compliance with environmental regulations. The research explores the isotopic composition of NO3 in relation to atmospheric nitrogen and Vienna Standard Mean Ocean Water, shedding light on the contributions from various sources such as manure, sewage, soil organic nitrogen, and nitrogen fertilizers. Specifically, there is a change in the δ15NAir value between the dry and wet seasons. The isotope values in the Tillman WWTP sample changed between dry and wet seasons. Notably, the presence of nitrate originating from manure and sewage is consistent across seasons, emphasizing the significant impact of anthropogenic and agricultural activities on water quality. This investigation contributes to the broader understanding of nitrogen cycling in urban water bodies, particularly in the context of wastewater effluent discharge. The findings hold implications for water quality management and highlight the need for targeted interventions to mitigate the impact of nitrogen-containing compounds on aquatic ecosystems. Overall, the study provides a valuable framework for future research and environmental stewardship efforts aimed at preserving the health and sustainability of urban water resources. This data informs decisions regarding additional treatment or mitigation actions to safeguard downstream water quality and ecosystem health.展开更多
As a typical car-dependent city, Los Angeles （LA） is extensively used as an example in research to illustrate car influences on city form. Focusing on the features of LA＇s geologic conditions and civil circumstance...As a typical car-dependent city, Los Angeles （LA） is extensively used as an example in research to illustrate car influences on city form. Focusing on the features of LA＇s geologic conditions and civil circumstances, we argued that the relationship between LA＇s low-density pattern and car dependence is more involved than previously deemed simple causality. The low density should be primarily credited to the spacious requirement of the mining industry, frequent earthquakes and multiethnic population of the city. Off reserves in LA fueled its economic boom and fast urbanization that coincided with the start of mass production of cheap cars, and cars became medium-priced consumables for average families. Politicians preference for short constrnction-period projects enabled fast establishment of LA＇s highway infrastructure. The popularity of car use in return faciliatated further development of the low-density pattern of the city. The low-density urban form and car dependence created environmental and social problems for LA. Looking at P. R. China＇s motorization and urban development, we found that the trajectory of Beijing＇s motorization between 197g and 2003 coincides with that of the U.S. in the 1910s and 1920s. Lessons from LA＇s urban and transportation development should be suggestive to China＇s urban and transportation planning.展开更多
On May 17, the series events of China Tourism and Culture Week hosted by the China Tourism Office in Los Angeles officially kicked off in Los Angeles. A number of culture and tourism promotion activities, including op...On May 17, the series events of China Tourism and Culture Week hosted by the China Tourism Office in Los Angeles officially kicked off in Los Angeles. A number of culture and tourism promotion activities, including opening ceremony, photo exhibition, handicraft exhibition of intangible cultural heritage, gourmet experience, tourism promotion, advertising and so on, have been held one after another.展开更多
On October 28, CES opened Shanghai-Harbin-Los Angelesairline, and the initial flight ceremony was held at Taiping InternationalAirport in Harbin. It was the first flight from Harbin to USA. Leaders ofHeilongjiang Prov...On October 28, CES opened Shanghai-Harbin-Los Angelesairline, and the initial flight ceremony was held at Taiping InternationalAirport in Harbin. It was the first flight from Harbin to USA. Leaders ofHeilongjiang Province, Harbin City and China Eastern Air HoldingCompany presented themselves on the initial flight ceremony.展开更多
Earth observation(EO) technologies,such as very high-resolution optical satellite data available from Maxar,can enhance economic consequence modeling of disasters by capturing the fine-grained and real-time behavioral...Earth observation(EO) technologies,such as very high-resolution optical satellite data available from Maxar,can enhance economic consequence modeling of disasters by capturing the fine-grained and real-time behavioral responses of businesses and the public.We investigated this unique approach to economic consequence modeling to determine whether crowd-sourced interpretations of EO data can be used to illuminate key economic behavioral responses that could be used for computable general equilibrium modeling of supply chain repercussions and resilience effects.We applied our methodology to the COVID-19 pandemic experience in Los Angeles County,California as a case study.We also proposed a dynamic adjustment approach to account for the changing character of EO through longer-term disasters in the economic modeling context.We found that despite limitations,EO data can increase sectoral and temporal resolution,which leads to significant differences from other data sources in terms of direct and total impact results.The findings from this analytical approach have important implications for economic consequence modeling of disasters,as well as providing useful information to policymakers and emergency managers,whose goal is to reduce disaster costs and to improve economic resilience.展开更多
洛杉矶是美国西海岸的一座大城市,处在一个地震多发地带。科学家们发现了洛杉矶地下的一个隐蔽的断层,并确认该断层是过去该市遭受地震灾害的元凶,还预言今后此断层将会造成更强烈的地震。这则消息无疑会在洛杉矶市民心头蒙上一层阴影,...洛杉矶是美国西海岸的一座大城市,处在一个地震多发地带。科学家们发现了洛杉矶地下的一个隐蔽的断层,并确认该断层是过去该市遭受地震灾害的元凶,还预言今后此断层将会造成更强烈的地震。这则消息无疑会在洛杉矶市民心头蒙上一层阴影,当然,对洛杉矶的房地产商人来说也许打击更大。本文涉及了不少地理知识,其中最有用的也许是:The amount of damage that a quake can do depends not only on its magnitude(量级),but its depth and the type of structures on the surface.】展开更多
AIM： To analyze the clinical and endoscopic features of Chinese patients with reflux esophagitis （RE）. METHODS： A total of 1405 RE patients were analyzed retrospectively. Data on gender, age, presence/absence of H...AIM： To analyze the clinical and endoscopic features of Chinese patients with reflux esophagitis （RE）. METHODS： A total of 1405 RE patients were analyzed retrospectively. Data on gender, age, presence/absence of H pylori infection and associated esophageal hiatal hernia were collected. Esophagitis was divided into different grades according to Los Angeles Classification. RESULTS： Of 18823 patients, 1405 were diagnosed as RE. The ratio of male to female patients was 1.75：1 （P 〈 0.01）. The mean age of male and female patients was significantly different （P = 0.01）. The peak age at onset of the disease was 40-60 years. According to Los Angeles Classification, there were significant differences in the age of patients with grades A and B compared to patients with grades C and D （P 〈 0.01）. Two hundred and seventy-seven patients were infected with H pyiorl, the infection rate was low （P 〈 0.01）. Complication of esophageal hiatal hernia was found to be significantly associated with the severity of esophagitis and age in 195 patients （P 〈 0.01）. Esophageal mucosa damages were mainly located at the right esophageal wall. CONCLUSION： The peak age of onset of RE is 40-60 years and higher in males than in females. The mean age of onset of RE is lower in males than in females. The infection rate of Hpylori is significantly decreased in patients with esophagitis. Old age and esophageal hiatal hernia are associated with more severe esophagitis. Right esophageal mucosal damage can occur more often in RE patients.展开更多
AIM: To compare the clinical efficacy of the secondgeneration H2 RA lafutidine with that of lansoprazole in Japanese patients with mild gastroesophageal reflux disease(GERD). METHODS: Patients with symptoms of GERD an...AIM: To compare the clinical efficacy of the secondgeneration H2 RA lafutidine with that of lansoprazole in Japanese patients with mild gastroesophageal reflux disease(GERD). METHODS: Patients with symptoms of GERD and a diagnosis of grade A reflux esophagitis(according to the Los Angeles classification) were randomized to receive lafutidine(10 mg, twice daily) or lansoprazole(30 mg, once daily) for an initial 8 wk, followed by maintenance treatment comprising half-doses of the assigned drug for 24 wk. The primary endpoint was the frequency and severity of heartburn during initial and maintenance treatment. The secondary endpoints were the sum score of questions 2 and 3 in the Gastrointestinal Symptom Rating Scale(GSRS), and the satisfaction score.RESULTS: Between April 2012 and March 2013, a total of 53 patients were enrolled, of whom 24 and 29 received lafutidine and lansoprazole, respectively. After 8 wk, the frequency and severity of heartburn was significantly reduced in both groups. However, lafutidine was significantly inferior to lansoprazole with regard to the severity of heartburn during initial and maintenance treatment(P = 0.016). The sum score of questions 2 and 3 in the GSRS, and satisfaction scores were also significantly worse in the lafutidine group than the lansoprazole group(P = 0.0068 and P = 0.0048, respectively).CONCLUSION: The clinical efficacy of lafutidine was inferior to that of lansoprazole, even in Japanese patients with mild GERD.展开更多
The difference in gastro-esophageal reflux disease (GERD) symptoms between elderly and younger GERD patients has not been fully studied. Our aim was to examine if there was any difference in the degree of GERD symptom...The difference in gastro-esophageal reflux disease (GERD) symptoms between elderly and younger GERD patients has not been fully studied. Our aim was to examine if there was any difference in the degree of GERD symptoms between elderly and younger patients with reflux esophagitis. Patients who were diagnosed by endoscopic examination as having reflux esophagitis and who answered the questionnaire on the frequency scale for the symptoms of GERD (FSSG) were included. Elderly and younger adult patients were defined as patients aged 65 and over or less than 65, respectively. 596 subjects were included. 184 subjects (mean 71.1 years;114 males) were classified into the Elderly group, and 412 subjects (mean 51.2 years;307 males) into the Younger group. The mean FSSG score of the Elderly and Younger groups was 6.7 and 8.4, respectively (p = 0.0024). Among those with severe esophagitis, the mean FSSG score of the Elderly and Younger groups was 8.5 and 8.7, respectively (p = 0.58). Although elderly patients tended to have less degree of GERD symptoms than younger patients, these findings suggest that there may be no significant age-related difference in complaints of GERD symptoms among severe reflux esophagitis patients.展开更多
The objective of this research is to study the effect of grinding powdered superplasticizer, Portland cement, sand, and silica fume on the properties of fresh and hardened concrete. Lose Angeles Machine was used to gr...The objective of this research is to study the effect of grinding powdered superplasticizer, Portland cement, sand, and silica fume on the properties of fresh and hardened concrete. Lose Angeles Machine was used to grind these constituents. The program was arranged to determine the effect of cycles＇ number, superplasticizer type and dosage, silica fume dosage and condition, and gravel to sand ratio on properties of concrete. Naphthalene sulphonated formaldehyde （NSF） superplasticizers in the forms of liquid and powdered were used. Silica fume may be grinded with the other constituents （grinded）, or added to concrete mixer （normal）. The water/cement （w/c） ratio varied from 0.35 to 0.55 to achieve a constant slump （50-90 mm）. Slumps, bulk density and mechanical properties of concrete were measured. Scanning electron microscope （SEM） was also used to show the differences between traditional and superplasticized concrete. The results showed that grinding the mixture enhances fresh and hardened concrete properties. It is also observed that grinding the mixture for 500 cycles is more effective than other numbers of grinding. In addition, superplasticized concrete exhibits compressive strength higher than traditional one at varied ages. Moreover, using powdered superplasticizer has a remarkable effect on enhancing concrete properties rather than using it in a liquid form. A dosage of 1% by weight of cement gave the highest results of compressive strength. Silica fume has an essential role in improving concrete strength and durability since it acts as very efficient void filler and as a super pozzolana. SEM observations illustrate that grinding the mixture enhances transition zone （TZ） properties and makes it denser. On the other hand, grinded mixture can be packaged in bags and transported for use in crowded cities, and so, enhances quality control, since the only requirement to obtain superplasticized concrete is to add water and gravel. This technique has many benefits such as; saving cement, labor and noise, high quality control, and enhancing concrete permeability and durability. There are many fields of application of superplasticized concrete such as; in locations which are not easily accessible by ordinary concreting techniques, in repairing and strengthen, thin coating, and for small projects when ready mix supply is not feasible.展开更多
第三部分:阅读理解(共20小题) 阅读下列短文,从每题所给的四个选项中,选出最佳选项。 A Fatigue(疲劳)can actually be considered akind of poisoning.When a muscle(肌肉)in ourbody works,it produces lactic acid(乳酸).If weremove...第三部分:阅读理解(共20小题) 阅读下列短文,从每题所给的四个选项中,选出最佳选项。 A Fatigue(疲劳)can actually be considered akind of poisoning.When a muscle(肌肉)in ourbody works,it produces lactic acid(乳酸).If weremove the lactic acid from a tired muscle,it willbe able to start working again at once.展开更多
文摘A metropolitan city such as Los Angeles (LA) is an ideal study site with a very high population density, and it houses at least 3 treatment plants where sewage is treated preliminarily and then progressing to tertiary treatment before discharging into the LA River. We will gain a better understanding of the water quality in the LA River and the nitrate load in the watershed system by examining the influence of waste water treatment plants (WWTPs). The goal of this study is to pinpoint the exact source of nitrate in the LA River using the isotope signatures. We have selected sampling locations both upstream and downstream of the WWTP. This serves to monitor nitrate levels, aiding in the assessment of treatment plant effectiveness, pinpointing nitrate pollution sources, and ensuring compliance with environmental regulations. The research explores the isotopic composition of NO3 in relation to atmospheric nitrogen and Vienna Standard Mean Ocean Water, shedding light on the contributions from various sources such as manure, sewage, soil organic nitrogen, and nitrogen fertilizers. Specifically, there is a change in the δ15NAir value between the dry and wet seasons. The isotope values in the Tillman WWTP sample changed between dry and wet seasons. Notably, the presence of nitrate originating from manure and sewage is consistent across seasons, emphasizing the significant impact of anthropogenic and agricultural activities on water quality. This investigation contributes to the broader understanding of nitrogen cycling in urban water bodies, particularly in the context of wastewater effluent discharge. The findings hold implications for water quality management and highlight the need for targeted interventions to mitigate the impact of nitrogen-containing compounds on aquatic ecosystems. Overall, the study provides a valuable framework for future research and environmental stewardship efforts aimed at preserving the health and sustainability of urban water resources. This data informs decisions regarding additional treatment or mitigation actions to safeguard downstream water quality and ecosystem health.
基金Funded by Key Project of the Natural Science Foundation of China under the grant No. 40635026.
文摘As a typical car-dependent city, Los Angeles （LA） is extensively used as an example in research to illustrate car influences on city form. Focusing on the features of LA＇s geologic conditions and civil circumstances, we argued that the relationship between LA＇s low-density pattern and car dependence is more involved than previously deemed simple causality. The low density should be primarily credited to the spacious requirement of the mining industry, frequent earthquakes and multiethnic population of the city. Off reserves in LA fueled its economic boom and fast urbanization that coincided with the start of mass production of cheap cars, and cars became medium-priced consumables for average families. Politicians preference for short constrnction-period projects enabled fast establishment of LA＇s highway infrastructure. The popularity of car use in return faciliatated further development of the low-density pattern of the city. The low-density urban form and car dependence created environmental and social problems for LA. Looking at P. R. China＇s motorization and urban development, we found that the trajectory of Beijing＇s motorization between 197g and 2003 coincides with that of the U.S. in the 1910s and 1920s. Lessons from LA＇s urban and transportation development should be suggestive to China＇s urban and transportation planning.
文摘On May 17, the series events of China Tourism and Culture Week hosted by the China Tourism Office in Los Angeles officially kicked off in Los Angeles. A number of culture and tourism promotion activities, including opening ceremony, photo exhibition, handicraft exhibition of intangible cultural heritage, gourmet experience, tourism promotion, advertising and so on, have been held one after another.
文摘On October 28, CES opened Shanghai-Harbin-Los Angelesairline, and the initial flight ceremony was held at Taiping InternationalAirport in Harbin. It was the first flight from Harbin to USA. Leaders ofHeilongjiang Province, Harbin City and China Eastern Air HoldingCompany presented themselves on the initial flight ceremony.
基金funded by the NASA Disasters Program grant#NH18ZDA001N001N.
文摘Earth observation(EO) technologies,such as very high-resolution optical satellite data available from Maxar,can enhance economic consequence modeling of disasters by capturing the fine-grained and real-time behavioral responses of businesses and the public.We investigated this unique approach to economic consequence modeling to determine whether crowd-sourced interpretations of EO data can be used to illuminate key economic behavioral responses that could be used for computable general equilibrium modeling of supply chain repercussions and resilience effects.We applied our methodology to the COVID-19 pandemic experience in Los Angeles County,California as a case study.We also proposed a dynamic adjustment approach to account for the changing character of EO through longer-term disasters in the economic modeling context.We found that despite limitations,EO data can increase sectoral and temporal resolution,which leads to significant differences from other data sources in terms of direct and total impact results.The findings from this analytical approach have important implications for economic consequence modeling of disasters,as well as providing useful information to policymakers and emergency managers,whose goal is to reduce disaster costs and to improve economic resilience.
文摘洛杉矶是美国西海岸的一座大城市,处在一个地震多发地带。科学家们发现了洛杉矶地下的一个隐蔽的断层,并确认该断层是过去该市遭受地震灾害的元凶,还预言今后此断层将会造成更强烈的地震。这则消息无疑会在洛杉矶市民心头蒙上一层阴影,当然,对洛杉矶的房地产商人来说也许打击更大。本文涉及了不少地理知识,其中最有用的也许是:The amount of damage that a quake can do depends not only on its magnitude(量级),but its depth and the type of structures on the surface.】
文摘AIM： To analyze the clinical and endoscopic features of Chinese patients with reflux esophagitis （RE）. METHODS： A total of 1405 RE patients were analyzed retrospectively. Data on gender, age, presence/absence of H pylori infection and associated esophageal hiatal hernia were collected. Esophagitis was divided into different grades according to Los Angeles Classification. RESULTS： Of 18823 patients, 1405 were diagnosed as RE. The ratio of male to female patients was 1.75：1 （P 〈 0.01）. The mean age of male and female patients was significantly different （P = 0.01）. The peak age at onset of the disease was 40-60 years. According to Los Angeles Classification, there were significant differences in the age of patients with grades A and B compared to patients with grades C and D （P 〈 0.01）. Two hundred and seventy-seven patients were infected with H pyiorl, the infection rate was low （P 〈 0.01）. Complication of esophageal hiatal hernia was found to be significantly associated with the severity of esophagitis and age in 195 patients （P 〈 0.01）. Esophageal mucosa damages were mainly located at the right esophageal wall. CONCLUSION： The peak age of onset of RE is 40-60 years and higher in males than in females. The mean age of onset of RE is lower in males than in females. The infection rate of Hpylori is significantly decreased in patients with esophagitis. Old age and esophageal hiatal hernia are associated with more severe esophagitis. Right esophageal mucosal damage can occur more often in RE patients.
文摘AIM: To compare the clinical efficacy of the secondgeneration H2 RA lafutidine with that of lansoprazole in Japanese patients with mild gastroesophageal reflux disease(GERD). METHODS: Patients with symptoms of GERD and a diagnosis of grade A reflux esophagitis(according to the Los Angeles classification) were randomized to receive lafutidine(10 mg, twice daily) or lansoprazole(30 mg, once daily) for an initial 8 wk, followed by maintenance treatment comprising half-doses of the assigned drug for 24 wk. The primary endpoint was the frequency and severity of heartburn during initial and maintenance treatment. The secondary endpoints were the sum score of questions 2 and 3 in the Gastrointestinal Symptom Rating Scale(GSRS), and the satisfaction score.RESULTS: Between April 2012 and March 2013, a total of 53 patients were enrolled, of whom 24 and 29 received lafutidine and lansoprazole, respectively. After 8 wk, the frequency and severity of heartburn was significantly reduced in both groups. However, lafutidine was significantly inferior to lansoprazole with regard to the severity of heartburn during initial and maintenance treatment(P = 0.016). The sum score of questions 2 and 3 in the GSRS, and satisfaction scores were also significantly worse in the lafutidine group than the lansoprazole group(P = 0.0068 and P = 0.0048, respectively).CONCLUSION: The clinical efficacy of lafutidine was inferior to that of lansoprazole, even in Japanese patients with mild GERD.
文摘The difference in gastro-esophageal reflux disease (GERD) symptoms between elderly and younger GERD patients has not been fully studied. Our aim was to examine if there was any difference in the degree of GERD symptoms between elderly and younger patients with reflux esophagitis. Patients who were diagnosed by endoscopic examination as having reflux esophagitis and who answered the questionnaire on the frequency scale for the symptoms of GERD (FSSG) were included. Elderly and younger adult patients were defined as patients aged 65 and over or less than 65, respectively. 596 subjects were included. 184 subjects (mean 71.1 years;114 males) were classified into the Elderly group, and 412 subjects (mean 51.2 years;307 males) into the Younger group. The mean FSSG score of the Elderly and Younger groups was 6.7 and 8.4, respectively (p = 0.0024). Among those with severe esophagitis, the mean FSSG score of the Elderly and Younger groups was 8.5 and 8.7, respectively (p = 0.58). Although elderly patients tended to have less degree of GERD symptoms than younger patients, these findings suggest that there may be no significant age-related difference in complaints of GERD symptoms among severe reflux esophagitis patients.
文摘The objective of this research is to study the effect of grinding powdered superplasticizer, Portland cement, sand, and silica fume on the properties of fresh and hardened concrete. Lose Angeles Machine was used to grind these constituents. The program was arranged to determine the effect of cycles＇ number, superplasticizer type and dosage, silica fume dosage and condition, and gravel to sand ratio on properties of concrete. Naphthalene sulphonated formaldehyde （NSF） superplasticizers in the forms of liquid and powdered were used. Silica fume may be grinded with the other constituents （grinded）, or added to concrete mixer （normal）. The water/cement （w/c） ratio varied from 0.35 to 0.55 to achieve a constant slump （50-90 mm）. Slumps, bulk density and mechanical properties of concrete were measured. Scanning electron microscope （SEM） was also used to show the differences between traditional and superplasticized concrete. The results showed that grinding the mixture enhances fresh and hardened concrete properties. It is also observed that grinding the mixture for 500 cycles is more effective than other numbers of grinding. In addition, superplasticized concrete exhibits compressive strength higher than traditional one at varied ages. Moreover, using powdered superplasticizer has a remarkable effect on enhancing concrete properties rather than using it in a liquid form. A dosage of 1% by weight of cement gave the highest results of compressive strength. Silica fume has an essential role in improving concrete strength and durability since it acts as very efficient void filler and as a super pozzolana. SEM observations illustrate that grinding the mixture enhances transition zone （TZ） properties and makes it denser. On the other hand, grinded mixture can be packaged in bags and transported for use in crowded cities, and so, enhances quality control, since the only requirement to obtain superplasticized concrete is to add water and gravel. This technique has many benefits such as; saving cement, labor and noise, high quality control, and enhancing concrete permeability and durability. There are many fields of application of superplasticized concrete such as; in locations which are not easily accessible by ordinary concreting techniques, in repairing and strengthen, thin coating, and for small projects when ready mix supply is not feasible.
文摘第三部分:阅读理解(共20小题) 阅读下列短文,从每题所给的四个选项中,选出最佳选项。 A Fatigue(疲劳)can actually be considered akind of poisoning.When a muscle(肌肉)in ourbody works,it produces lactic acid(乳酸).If weremove the lactic acid from a tired muscle,it willbe able to start working again at once.
