GNSS-R信号反演土壤水分研究分析

由于GNSS-R信号具有全天候、穿透性以及不受云的影响,且对土壤水分非常敏感等特性,使其在遥感研究全球变化中具有独特的优势。简要评述了利用GPS地面反射信号在土壤水分反演研究领域的进展,然后侧重分析介绍了GPS反射信号土壤水分反演原理,前向模型分析反演土壤水分的关键技术,并指出目前存在的问题和发展方向。     

An examination of the temporal effects of environmental cues on pedestrians' feelings of safety

Although plans are made with people as the target, plan-making processes in most instances are dominated by top-down approaches, giving very little regard to how people perceive or feel about the cities they live in. The perceptions urban areas trigger and how these cause behavioural changes reflect the implications of planning and decision-making upon them. Prior studies indicate that environmental factors can trigger affective reactions in people. Thus, throughout this study, it was attempted to understand how environmental factors affect University students' perceptions of safety, which were quantified on the basis of their arousal, i.e. the calmness or stress felt, and walking speeds. Data on arousal were captured in real-time by a technically-sound, low-cost device assembled using free and open source software and hardware. The study could demarcate and rank the areas perceived to be “safe” and “unsafe” by the University students in real-time using the assembled device and identify which environmental factors have the most significant influence on their perception of safety. This study introduces the chance to determine unconscious reactions of people by triangulating data gathered by several measurement techniques that are directly measured in the field, which can be served as useful inputs for urban planning. Furthermore, the study confirms the value of the real-time sensing device as a tool beyond traditional methods in understanding feelings of safety in environmental settings.     

基于主成分分析与偏最小二乘法建立芒果成熟度判定指标体系

为建立“台农1号”芒果成熟度判定指标体系,并确定代表性成熟度判定指标,以不同采收期、不同产地的“台农1号”芒果为研究对象,分析果实后熟生理指标果肉和果皮色泽、质构（硬度、胶着性、弹性、咀嚼性）、可溶性固形物、可滴定酸的变化,基于主成分分析与偏最小二乘法方法进行果实后熟生理指标系统研究。结果表明：在以商户初始采收成熟度相同的条件下,各批次“台农1号”芒果果实后熟生理指标间存在差异。应用偏最小二乘法方法与主成分分析方法确定了果肉b*、可滴定酸、硬度作为评判果实成熟度的一、二、三级最终指标,通过三个指标的成熟度判定准确率验证一级指标为94.34%,二级指标为87.21%,三级指标为68.09%。综上所述,基于主成分分析与偏最小二乘法建立芒果成熟度判定指标体系是可行的,该研究为各地区“台农1号”芒果适时采收及销售提供理论指导和实用价值。     

Crop yields and soil organic carbon fractions as influenced by straw incorporation in a rice–wheat cropping system in southeastern China

In agro-ecosystems, the relationship between soil fertility and crop yield is mediated by manure application. In this study, an 8-year field experiment was performed with four fertilizer treatments (NPK, NPKM₁, NPKM₂, and NPKM₃), where NPK refers to chemical fertilizer and M₁, M₂, and M₃ refer to manure application rates of 15, 30, and 45 Mg ha^?1 year^?1, respectively. The results showed that the NPKM (NPKM₁, NPKM₂, and NPKM₃) treatments produced greater and more stable yields (4.95–5.45 Mg ha^?1 and 0.59–0.75) than the NPK treatment (4.01 Mg ha^?1 and 0.50). Crop yields under the NPKM treatments showed two trends, with a rate of decrease of 0.48–0.83 Mg ha^?1 year^?1 during the first 4 years and a rate of increase of 0.10–0.25 Mg ha^?1 year^?1 during the last 4 years. The soil organic carbon (SOC) significantly increased under all treatments. The estimated annual SOC decomposition rate was 0.35 Mg ha^?1 year^?1 and the equilibrium SOC level was 6.22 Mg ha^?1. Soil total nitrogen (N), available N, total phosphorus (P) and available P under the NPKM treatments increased by 0.15–0.26, 15–33, 0.17–0.66 and 45–159 g kg^?1, respectively, compared with the NPK treatment. Manure application mainly influenced crop yield by affecting the soil TN, available N, and available P, which accounted for up to 64% of the crop yield variation. Taken together, applying manure can determine or at least improve the effects of soil fertility on crop yield in acidic soils in South China.     

Confucian ecological vision and the Chinese eco-city

“Living in harmony with nature” is the slogan of the Chinese government’s campaign against the environmental crisis and has become the target of many mega eco-city projects which have emerged in China during the last decade. A number of papers in Chinese journals attribute this slogan to the government’s revival of the Confucian ecological vision, combined with western technology. This paper first compares the concept of nature in these mega eco-cities and the Confucian concept of tianrenheyi, the unity of Heaven and Humanity, suggesting that the human–nature relationship in eco-cities is essentially a consumer–commodity relationship, which is void of the sacredness or moral association of the human–nature relationship in the unity of Heaven and Humanity. Secondly, drawing on the theory of ecology and interconnected systems and noting that the failure of eco-city projects lies in the separation of the eco-city from the city itself, I suggest that the eco-city’s approach of taking nature as a guinea pig of technology in a “vacuum space” is quite opposite to the Confucian idea of the unity of Heaven and Humanity which emphasizes the interconnectedness of all inorganic and organic forms. In conclusion, I evoke Wang Shu’s practice of sustainable architecture to illustrate a more authentic, up-to-date interpretation of the Confucian ecological vision—investigating the relational reality, developing one’s moral nature and cultural intuition.     

Inverting a forest canopy reflectance model to retrieve the overstorey and understorey leaf area index for forest stands

In this article, the Kuusk–Nilson forest reflectance and transmittance (FRT) model was inverted to retrieve the overstorey and understorey leaf area index (OU-LAI) of forest stands in the Longmenhe forest nature reserve in China. Data from detailed sample sites were collected in 30 forest stands representing the typical vegetation community in the study area. An uncertainty and sensitivity matrix (USM) was used to analyse the sensitivity of the FRT model parameters based on these data. The results indicated that overstorey LAI strongly influenced stand reflectance, whereas understorey LAI had a much lower impact. To predict OU-LAI in forest stands, FRT model inversion is carried out by minimizing a merit function that provides a measure of the difference between the reflectance simulated by the FRT model and the reflectance originating from optimal band selection of Hyperion data. Various combinations of Hyperion bands were tested to evaluate the most effective wavelengths for the inversion of OU-LAI. The best estimates from 17 Hyperion bands (5 VIS, 8 NIR, 4 SWIR) by the FRT model inversion showed an R ²?=?0.41 and RMSE/mean?=?0.21 for overstorey LAI and R ²?=?0.49 and RMSE/mean?=?0.91 for understorey LAI. Advantages and disadvantages of FRT inversion for retrieval OU-LAI combined with Hyperion data are discussed.     

Conventional freezing plus high pressure–low temperature treatment: Physical properties,microbial quality and storage stability of beef meat

Meat high-hydrostatic pressure treatment causes severe decolouration, preventing its commercialisation due to consumer rejection. Novel procedures involving product freezing plus low-temperature pressure processing are here investigated. Room temperature (20 °C) pressurisation (650 MPa/10 min) and air blast freezing (−30 °C) are compared to air blast freezing plus high pressure at subzero temperature (−35 °C) in terms of drip loss, expressible moisture, shear force, colour, microbial quality and storage stability of fresh and salt-added beef samples (Longissimus dorsi muscle). The latter treatment induced solid water transitions among ice phases. Fresh beef high pressure treatment (650 MPa/20 °C/10 min) increased significantly expressible moisture while it decreased in pressurised (650 MPa/−35 °C/10 min) frozen beef. Salt addition reduced high pressure-induced water loss. Treatments studied did not change fresh or salt-added samples shear force. Frozen beef pressurised at low temperature showed L, a and b values after thawing close to fresh samples. However, these samples in frozen state, presented chromatic parameters similar to unfrozen beef pressurised at room temperature. Apparently, freezing protects meat against pressure colour deterioration, fresh colour being recovered after thawing. High pressure processing (20 °C or −35 °C) was very effective reducing aerobic total (2-log₁₀ cycles) and lactic acid bacteria counts (2.4-log₁₀ cycles), in fresh and salt-added samples. Frozen + pressurised beef stored at −18 °C during 45 days recovered its original colour after thawing, similarly to just-treated samples while their counts remain below detection limits during storage.     

Efficacy of the theory of planned behaviour model in predicting safe food handling practices

The majority of food-borne disease outbreaks result from malpractice during food preparation in small food businesses. Effective food safety management, including the adoption of safe food handling practices learnt during food safety training programmes, is thus an important strategy to limit incidences of food poisoning. This study explores the impact of basic or foundation level food hygiene training on the attitudes, and intentions of food handlers to conduct safe food handling practices at every occasion.The Theory of Planned Behaviour was used to evaluate the relative impact of different influences on the intentions and self-reported behaviours of 249 food handlers, in hospitality settings. Interviews were also conducted with food handlers, and their managers to seek further insight into the changes in attitude and intent to conduct safe food handling practices after basic or foundation level food hygiene training.     

Electrochemical study of enargite bioleaching by mesophilic and thermophilic microorganisms

The bioleaching effects of two microorganisms on two different enargite (Cu₃AsS₄) minerals have been followed by solution titration and rest potential measurements and studied by cyclic voltammetry. The investigation focused on the superficial modifications produced in the minerals by the activity of the mesophilic bacterium Acidithiobacillus ferrooxidans at 35 °C and the thermophilic archaeon Sulfolobus sp. at 68 °C after 3 and 12 days of attack, comparing the modified surfaces with that of untreated samples. The electrochemical characterization of all the electrodes was done by means of potentiometric assays performed under the same conditions: acidulated deionized water as electrolyte (pH 2.0), and temperature of 26 ± 2 °C. Additionally, a comparative SEM and EDX study of untreated and biotreated samples was carried out.