Willingness of residents to pay and motives for conservation of urban green spaces in the compact city of Hong Kong     

Alex Y. Lo  C.Y. Jim 《Urban Forestry & Urban Greening》2010,9(2):113-120

People attach multiple values to urban green spaces which play varied roles in cities. Properly designed monetary valuation surveys can ascertain their non-market value and underlying motives. This study investigates Hong Kong residents’ recreational use of urban green spaces and assesses the monetary value of these areas. A total of 495 urban residents from different neighbourhoods and socio-economic groups were interviewed. About 70% of the respondents visited urban green spaces at least weekly. Major companions during patronage were family members and then children. Exercises and clean air topped the list of visit purposes. The recreational pattern is associated with the cramped private living condition that pushes people to public open areas which are construed as extension of home space. The valuation question solicited overwhelming support, with over 80% of the respondents willing to pay to recover a possible loss of urban green spaces area by 20%. It yielded a monthly average payment of HK$77.43 (approx. 9.90 USD) per household for five years. Non-instrumental aspects played some role in the respondents’ bidding decision. The findings could assist green space planning and nature conservation, and hinted the need to consider the pluralistic community views and expectations in relevant public policies.  相似文献   

Arsenic accumulation by rice grown in soil treated with roxarsone     

Chen‐Wuing Liu  Ching‐Chieh Lin  Cheng‐Shin Jang  Guey‐Rong Sheu  Lo Tsui 《植物养料与土壤学杂志》2009,172(4):550-556

Poultry litter is widely used as a fertilizer for lowland rice in Taiwan and China. However, the organic‐arsenic compound roxarsone (additive of poultry feed) in poultry litter can be absorbed by the plants and the resulting arsenic (As) contamination may pose a serious threat to human health. This study used various amounts of poultry litter contaminated with roxarsone in pot experiments to evaluate the effect of roxarsone on rice agronomic parameters and the bioaccumulation of total and inorganic As in rice‐plant tissues. Rice‐grain yield decreased significantly with increasing As content of the soil, and the critical threshold that killed rice was 200 mg roxarsone (kg soil)^–1. The As concentrations in root, straw, leaf, husk, and grain increased with increasing soil As (p < 1%). At 100 mg roxarsone per kg of soil, the As concentration in the rice grain exceeded the statutory permissible limit of 1.0 mg As (kg dry weight)^–1 and at 25 mg roxarsone (kg soil)^–1, the inorganic As concentrations in grains exceeded the statutory limit of 0.15 mg of inorganic As kg^–1 in China. For all treatments, the As concentrations in various plant tissues at maturity follow the order: root > stem > leaf > husk > grain. Arsenite was the predominant species in root, straw, and grain, while arsenate was the predominant species in leaf and husk. No significant difference existed between the amounts of arsenite and arsenate when various amounts of poultry litter were applied. This result illustrates that large amounts of added roxarsone are not only toxic to rice but also accumulate in grains in the inorganic As forms, potentially posing a threat to human health via the food chain.  相似文献   

Assessment of synthetic chemicals for disruption of Rhynchophorus ferrugineus response to attractant-baited traps in an urban environment     

Salvatore Guarino  Ezio Peri  Paolo Lo Bue  Maria Pia Germanà  Stefano Colazza  Leonid Anshelevich  Uzi Ravid  Victoria Soroker 《Phytoparasitica》2013,41(1):79-88

The red palm weevil (RPW), Rhynchophorus ferrugineus Olivier (Coleoptera, Curculionidae), is one of the most severe pests of ornamental palm species in urban areas of Mediterranean countries. Aiming to discover inhibitory semiochemicals for RPW population management in urban environments, we conducted electroantennographic (EAG) screenings of 17 commercially available synthetic compounds, representing three groups of plant volatiles (isoprenoids, phenyl propanoid derivatives and fatty acid derivatives) known for their repellent effects toward insects. These tests were followed by trap-based screenings of EAG-active menthone, α-pinene and methyl salicylate, singly and in combination, under urban conditions. In EAG bioassays, RPW antennae of both sexes showed positive dose-dependent responses to 13 of the 17 synthetic chemicals with significant differences among them. In field trapping experiments, conducted in the city of Palermo, Italy, from weeks 31 to 38 in 2010 and 2011, α-pinene, tested singly or in combination with methyl salicylate (2010) or menthone (2011), reduced trap catches by about 30% to 40%. Methyl salicylate and menthone alone were inactive. In conclusion, RPW is significantly affected by α-pinene. This isoprenoid is a promising disruptant for semiochemical-based management of this pest. In addition, identification of a large number of EAG-active chemicals could serve as a database for future design of active repellents or attractants of RPW adults.  相似文献   

Seed phosphorus remobilization is not a major limiting step for phosphorus nutrition during early growth of maize     

Muhammad Nadeem  Alain Mollier  Christian Morel  Alain Vives  Loïc Prud'homme  Sylvain Pellerin 《植物养料与土壤学杂志》2012,175(6):805-809

Phosphorus (P) is the least mobile nutrient in the soil as compared to other macronutrients and therefore frequently limits crop growth. During germination and early growth, seed‐phytate hydrolysis and seed‐P remobilization is the major P source for developing seedlings. The objective of this paper was to investigate whether seed‐P hydrolysis and remobilization of nonphytate P are sufficient for seedling P nutrition during early growth stages of maize. A large part of initial maize endogenous seed P reserves are mainly in the form of phytate. Till 70 cumulated degree days after sowing, nearly all the phytate (98%) was hydrolyzed and caused an increase in nonphytate P in seeds. Phytate hydrolysis and remobilization of nonphytate P was the main source of P supply for the newly growing seedlings and was not a limiting step for seedling P nutrition during the first four weeks of early growth.  相似文献   

Prospective evaluation of minimally invasive plate osteosynthesis in 36 nonarticular tibial fractures in dogs and cats     

Guiot LP  Déjardin LM 《Veterinary surgery : VS》2011,40(2):171-182

Objective: To evaluate the clinical outcome of minimally invasive plate osteosynthesis (MIPO) for nonarticular tibial fractures stabilized using bone plates with or without an intramedullary rod (IMR). Study Design: Prospective study. Animals: Dogs (n=28) and 8 cats. Methods: After closed reduction, fracture fixation was achieved using an epiperiosteal plate inserted percutaneously through epiphyseal small incisions. In some fractures, an IMR was inserted via medial parapatellar arthrotomy. Radiographs were recommended every 3 weeks until clinical union. Postoperative tibial length and alignment were compared with contralateral measurements (P<.05). Time to clinical union and complications were recorded. Results: An IMR was used in 30.5% of the cases. Repaired tibiae were 1% shorter than contralateral tibiae (P<.05). Frontal and sagittal alignment were similar between repaired and contralateral tibiae (P>.05). Six dogs were lost for follow‐up; owners indicated normal function. In 30 cases for which bone healing was documented, mean±SD healing time was 45±20.8 days; however, when considering the 23 cases, which completed preestablished scheduled follow‐ups, healing time was 36±11.6 days. Minor complications occurred in 4 cases (11%). One major complication (3%) consisting of a plate fracture was successfully revised using MIPO with a larger plate. Conclusions: Consistent restoration of alignment was accomplished using MIPO techniques. Furthermore, MIPO appeared to yield faster healing times and lower complication rates than those reported with conventional plate osteosynthesis.  相似文献   

Pathogenesis of leptospirosis: the influence of genomics     

Adler B  Lo M  Seemann T  Murray GL 《Veterinary microbiology》2011,153(1-2):73-81

Leptospirosis is the most widespread zoonosis worldwide and is caused by serovars of pathogenic Leptospira species. The understanding of leptospiral pathogenesis lags far behind that of many other bacterial pathogens. Current research is thus directed at identification of leptospiral virulence factors. Saprophytic Leptospira species are environmental organisms that never cause disease. Comparative genomics of pathogens and saprophytes has allowed the identification of more than 900 genes unique to either Leptospira interrogans or Leptospira borgpetersenii; these genes potentially encode virulence-associated proteins. However, genes of unknown function are over-represented in this subset of pathogen-specific genes, accounting for 80% and 60% of open reading frames, respectively. This finding, together with the absence of virulence factor homologues among the proteins of known function, suggests that Leptospira possesses unique virulence mechanisms. Whole genome microarray studies have identified genes whose expression is differentially regulated under a range of simulated in vivo conditions, such as physiological temperature and osmolarity, low iron levels, and the presence of serum. The subset of genes identified by these studies is likely to include virulence factors. However, most such genes encode proteins of unknown function, consistent with the hypothesis that leptospiral virulence genes do not have homologues in other bacterial species. The recent development of mutagenesis systems for pathogenic Leptospira spp. has allowed the screening of defined mutants for attenuation of virulence in animal infection models and has identified definitively for the first time a range of virulence factors, including lipopolysaccharide, flagella, heme oxygenase, and the OmpA-family protein, Loa22. Interestingly, inactivation of a number of genes hypothesised to encode virulence factors based on in vitro virulence-associated properties did not result in attenuation of virulence, suggesting a degree of functional redundancy in leptospiral pathogenic mechanisms.  相似文献   

Genetic diversity in seven populations of Nicaraguan teosinte (<Emphasis Type="Italic">Zea nicaraguensis</Emphasis> Iltis et Benz) as estimated by microsatellite variation     

Carlos Henry Loáisiga  Agnese Kolodinska Brantestam  Oscar Diaz  Björn Salomon  Arnulf Merker 《Genetic Resources and Crop Evolution》2011,58(7):1021-1028

Teosintes are the closest relatives to modern maize, Zea mays L. ssp. mays. They are wild grasses with a native distribution area from Mexico to Nicaragua and represent an important genetic resource. However, the genetic diversity of Nicaraguan teosinte (Zea nicaraguensis Iltis et Benz) has not yet been determined. This teosinte species has decreased in the last 25 years and now must be regarded as an endangered species. An analysis of the genetic diversity of Zea nicaraguensis was carried out in a total of 240 individuals from seven populations. Eleven Simple Sequences Repeat (SSR) primer pairs were used. A total of 42 alleles were found, the range of alleles per locus was 2–5 (mean 3.8) and the numbers of genotypes varied between primers. The primer Bnlg 1538 showed the highest value, with 45 genotypes through all populations. The genetic diversity observed (Ho) between all populations varied from 0.51 to 0.63, with an average of 0.563. One of the populations had as many as 40 alleles. Analysis of molecular variance (AMOVA) revealed that most of the variation was within population, at a significantly high level (P < 0.001). Rare alleles were detected in all populations, but unique alleles were only found in four populations. These results are highly relevant when developing conservation strategies and show that preserving populations in their natural habits is highly important.  相似文献   

Conceptual model and sensitivity analysis for simulating the extraction kinetics of soil washing     

Daniel C. W. Tsang  Theo C. M. Yip  Irene M. C. Lo 《Journal of Soils and Sediments》2011,11(7):1221-1233

Purpose  

Most previous studies focused on the metal extraction efficiency of chelant-enhanced soil washing under various operational conditions; however, one of the keys to cost-effective field application is to maintain a high throughput rate (i.e., short washing time) while achieving the treatment objectives. Therefore, this study presented a conceptual model for simulating the kinetic extraction of heavy metals and evaluated its sensitivity analysis to the predetermined parameter values in five soils with different initial metal distributions.  相似文献   

Using Seven Types of GM (1, 1) Model to Forecast Hourly Particulate Matter Concentration in Banciao City of Taiwan     

Tzu-Yi Pai  Ching-Lin Ho  Shyh-Wei Chen  Huang-Mu Lo  Pao-Jui Sung  Shu-Wen Lin  Wei-Jia Lai  Shih-Chi Tseng  Shu-Ping Ciou  Jui-Ling Kuo  Jing-Tang Kao 《Water, air, and soil pollution》2011,217(1-4):25-33

In this study, seven types of first-order and one-variable grey differential equation model (abbreviated as GM (1, 1) model) were used to predict hourly particulate matter (PM) including PM₁₀ and PM_2.5 concentrations in Banciao City of Taiwan. Their prediction performance was also compared. The results indicated that the minimum mean absolute percentage error (MAPE), mean squared error (MSE), root mean squared error (RMSE), and maximum correlation coefficient (R) was 14.10%, 25.62, 5.06, and 0.96, respectively, when predicting PM₁₀. When predicting PM_2.5, the minimum MAPE, MSE, RMSE, and maximum R value of 15.24%, 11.57, 3.40, and 0.93, respectively, could be achieved. All statistical values revealed that the predicting performance of GM (1, 1, x ⁽⁰⁾), GM (1, 1, a), and GM (1, 1, b) outperformed other GM (1, 1) models. According to the results, it revealed that GM (1, 1) GM (1, 1) was an efficiently early warning tool for providing PM information to the inhabitants.  相似文献   

野生防风与栽培防风多糖含量比较   总被引：6，自引：1，他引：5  

娄志红  江延辉  孟祥才 《特产研究》2000,22(2):25-26

采用苯酚－硫酸法测得栽培防风的多糖含量是野生防风的２倍以上。  相似文献