基于神经网络模型的千岛湖清洁水体叶绿素a遥感反演研究

叶绿素a浓度值是水体水质评价的重要指标,研究基于高分一号(GF-1)卫星遥感影像,利用神经网络模型,选用6节点的隐含层设置,构建了千岛湖清洁水体叶绿素a浓度反演模型,对其叶绿素a浓度值时空特征进行分析,并与其他常规反演方法精确度进行比较.研究结果表明,利用神经网络模型对千岛湖清洁水体叶绿素a浓度值进行反演是可行的,且与其他常规方法相比,该模型对于叶绿素a含量低的内陆清洁水体反演有着更高的相关性(R2 = 0.921 8);在空间分布上,千岛湖区域水体叶绿素a浓度整体较低,高叶绿素a浓度区域主要集中易受人类活动干扰的西南及东北区域;年际变化分析表明,千岛湖区域水体叶绿素a浓度稳定,且波动较小,平均叶绿素a浓度值皆维持在1.70～1.75 pg/L之间,清洁水体特征显著.     

2,4-Dichlorophenoxyacetic acid (2,4-D) photodegradation on WO3-TiO2-SBA-15 nanostructured composite

Environmental Science and Pollution Research - A current environmental problem is the uncontrolled use of various pesticides that are harmful to the environment and public health. The herbicide...     

Institutional quality,financial development and sustainable economic growth among lower income countries

This article postulates strong endogenous relationships in lower income countries between institutional quality, financial development and sustained economic growth. These associations were investigated using the vector-error correction model (VECM) and Granger causality method for a sample of 79 countries from 2005 to 2022. The findings show that (1) these variables reinforce each other in the short run. (2) In the long run, both institutional quality and financial development can fuel economic growth. (3) The positive effect of institutional quality on economic growth is greater than that of financial development. Policy implications of these findings are that careful attention should be paid to co-development policies to enhance the institutional quality and the financial system in these economies. Policies should also consider economic growth strategies to enable sustainable economic growth rates.     

Can nuclear aquatic environmental DNA be a genetic marker for the accurate estimation of species abundance?

The Science of Nature - We present the first study that compares phenological variation in parasite load and inflammatory response in a lizard with asynchronous male and female gonadal cycles....     

Analysis and optimization on the biodegradable plate making process parameters using RSM-based Box–Behnken Design method

Journal of Material Cycles and Waste Management - The present research work focused on fabricating Biodegradable Plate (BD plate) composed of rice husk ash, bagasse and corn starch which is...     

Toxicity of uranium mine receiving waters to early life stage fathead minnows (Pimephales promelas) in the laboratory.

Elevated concentrations of arsenic, nickel, and molybdenum in aquatic systems around northern Saskatchewan uranium mines are an environmental concern. Early life stage fathead minnows were used to assess toxicity from several aquatic systems near the Key Lake and Rabbit Lake uranium operations. Hatching success of fish embryos exposed to waters receiving contaminants associated with uranium ore milling was reduced by 32-61% relative to controls. Mortality differed in two lakes receiving mill effluents because of opposing factors influencing metal toxicity (i.e. low pH and high hardness). In one mill receiving water (Fox Lake), larval mortality was 0%, whereas mortality was 85% in water collected from a downstream location (Unknown Lake). Fish embryos exposed to open-pit dewatering effluent receiving waters, or water from a flooded open pit (i.e. pit waters), hatched 26-39% earlier than those exposed to reference or control water. The combination of low water hardness and elevated nickel concentrations in pit waters contributed to the early hatching. Egg hatchability and hatching time were more sensitive indicators of toxicity than 'standard' endpoints, like larval mortality and growth. Current regulatory emphasis on single contaminants and standard toxicological endpoints should be re-evaluated in light of the complex interaction among confounding variables such as pH, hardness. conductivity, and multi-metal mixtures.     

Effects of two organophosphorus insecticides on some biochemical constituents in the nervous system and liver of rabbits

Male Baladi rabbits were acutely and sub-chronically intoxicated with cyanofenphos and profenophos. The levels of cholesterol, triglycerides, B-lipoproteins and total proteins were determined in the serum, brain, spinal cord and sciatic nerve of rabbits. Moreover, the activities of alkaline phosphatase, acid phosphatase and glutamic-pyruvic transaminase were determined in the liver of the animals. The whole studies revealed that the biochemical constituents were highly affected by the tested insecticides. Also, the liver function suffered from adverse effects of the tested insecticides.