Carbon dioxide partial pressure and its diffusion flux in karst surface aquatic ecosystems:a review

Carbon dioxide(CO_(2))emissions from aquatic ecosystems are an important component of the karst carbon cycle process and also a key indicator for assessing the effect of karst carbon sinks.This paper reviewed the CO_(2)partial pressure(pCO_(2))and its diffusion flux(FCO_(2))in karst surface aquatic ecosystems,mainly rivers,lakes,and reservoirs,and their influencing factors summarized the methods for monitoring CO_(2)emissions in karst aquatic ecosystems and discussed their adaptation conditions in karst areas.The pCO_(2)and FCO_(2)decreased in the order of rivers>reservoirs>lakes,and the values in karst lakes were eventually significantly lower than those in global lakes.The pCO_(2)and FCO_(2)of karst aquatic ecosystems had patterns of variation with diurnal,seasonal,water depth and hydrological cycles,and spatial and temporal hetero-geneity.The sources of CO_(2)in karst waters are influenced by both internal and external sources,and the key spatial and temporal factors affecting the CO_(2)emissions from karst rivers,lakes,and reservoirs were determined in terms of physicochemical indicators,biological factors,and bio-genic elements;additionally,the process of human activity interference on CO_(2)emissions was discussed.Finally,a conceptual model illustrating the impacts of urban devel-opment,agriculture,mining,and dam construction on the CO_(2)emissions at the karst surface aquatic ecosystem is presented.Meanwhile,based on the disadvantages existing in current research,we proposed several important research fields related to CO_(2)emissions from karst surface aquatic ecosystems.

Element geochemical characteristics of a soil profile developed on dolostone in central Guizhou, southern China: implications for parent materials

This study presents bulk chemical compositions of the Tongmuling soil profile, which developed on dolostone, and the overlying strata covering the bedrock in the central Guizhou province(southern China). The chemical weathering characteristics of the studied profile were investigated and the inheritance relationships between the terra rossa and overlying strata were discussed. The results show that there is no remarkable variation in the major elements and weathering indices from the rock–soil interface to the topsoil, indicating that the studied profile was not typical for in situ crustal chemical weathering. The terra rossa were mainly composed of Si O_2, Al_2O_3 and Fe_2O_3. Compared with the insoluble residues and overlying strata, the terra rossa are characterized by an enrichment of Y and Cs and depletion of Ba and Sr. The subsoil shows a notable Ce negative anomaly, characterized by heavy rare earth element enrichment(L/H = 1.55–3.74), whereas the topsoil shows a positive Ce anomaly with light rare earth element enrichment(L/H = 5.93–9.14). According to Laterite-forming capacity estimates, the terra rossa could not have only been formed from acid-insoluble residues from the bedrock; Al_2O_3 versus Fe_2O_3and Nb plotted against Ta show significant positive correlations between the terra rossa and overlying strata. The Eu/Eu* versusGd_N/Yb_Nand ternary diagrams for Sc, Th, Zr, and Ta suggest that the overlying strata could also provide parent materials for the genesis of terra rossa.

A Location Prediction Method Based on GA-LSTM Networks and Associated Movement Behavior Information

Due to the lack of consideration of movement behavior information other than time and location perception in current location prediction methods,the movement characteristics of trajectory data cannot be well expressed,which in turn affects the accuracy of the prediction results.First,a new trajectory data expression method by associating the movement behavior information is given.The pre-association method is used to model the movement behavior information according to the individual movement behavior features and the group movement behavior features extracted from the trajectory sequence and the region.The movement behavior features based on pre-association may not always be the best for the prediction model.Therefore,through association analysis and importance analysis,the final association feature is selected from the pre-association features.The trajectory data is input into the LSTM networks after associated features and genetic algorithm(GA)is used to optimize the combination of the length of time window and the number of hidden layer nodes.The experimental results show that compared with the original trajectory data,the trajectory data associated with the movement behavior information helps to improve the accuracy of location prediction.

A narrative review of glaucoma screening from fundus images

The objective of the paper is to provide a general view for automatic cup to disc ratio(CDR)assessment in fundus images.As for the cause of blindness,glaucoma ranks as the second in ocular diseases.Vision loss caused by glaucoma cannot be reversed,but the loss may be avoided if screened in the early stage of glaucoma.Thus,early screening of glaucoma is very requisite to preserve vision and maintain quality of life.Optic nerve head(ONH)assessment is a useful and practical technique among current glaucoma screening methods.Vertical CDR as one of the clinical indicators for ONH assessment,has been well-used by clinicians and professionals for the analysis and diagnosis of glaucoma.The key for automatic calculation of vertical CDR in fundus images is the segmentation of optic cup(OC)and optic disc(OD).We take a brief description of methodologies about the OC and disc optic segmentation and comprehensively presented these methods as two aspects:hand-craft feature and deep learning feature.Sliding window regression,super-pixel level,image reconstruction,super-pixel level low-rank representation(LRR),deep learning methodologies for segmentation of OD and OC have been shown.It is hoped that this paper can provide guidance and bring inspiration to other researchers.Every mentioned method has its advantages and limitations.Appropriate method should be selected or explored according to the actual situation.For automatic glaucoma screening,CDR is just the reflection for a small part of the disc,while utilizing comprehensive factors or multimodal images is the promising future direction to furthermore enhance the performance.

Effects of acid mine drainage on photochemical and biological degradation of dissolved organic matter in karst river water

Dissolved organic matter(DOM)can be removed or transformed by photochemical and biological processes,producing the negative effect of transforming organic carbon into inorganic carbon,which plays a vital role in the karst carbon cycle.However,acid mine drainage(AMD)will affect this process,so the degradation of DOM in karst river water(KRW)needs to be studied in this context.In this study,to reveal the evolution processes of DOM under photochemical and biological conditions in AMD-impacted KRW,AMD and KRW were mixed in different ratios under conditions of visible light irradiation(VL),biodegradation(BD),ultraviolet irradiation(UV)and ultraviolet irradiation+biodegradation(UV+BD).The average DOC concentrations in samples after mixing AMD and KRW in different proportions decreased significantly(by 23%)in UV+BD,which was 1.2–1.4 times higher than under the other conditions and would lead to a significant release of inorganic carbon.Further analysis of the fluorescence parameters via parallel factor analysis(PARAFAC)revealed that the DOM fluorescence components in AMD comprised mainly protein-like substances derived from autochthonous components,while the DOM fluorescence components in KRW were mainly humic-like substances with both autochthonous and allochthonous sources.Therefore,AMD could promote both the photochemical and biological degradation of DOM in karst receiving streams,resulting in the conversion of DOC to inorganic carbon.The results showed that the synergistic effects of UV+BD and AMD accelerated the degradation of DOM and the release of inorganic carbon in KRW,thus affecting the stability of the karst carbon cycle.

A Novel Ratiometric Fluorescent Probe for Highly Sensitive and Selective Detection of β-Galactosidase in Living Cells

β-Galactosidase,a glycoside hydrolase enzyme,has been proved to be an important biomarker of cell senescence and primary ovarian cancer.Effective detection of β-galactosidase has attracted wide attention.Herein,one ratiometric fluorescent probe has been successfully synthesized for detecting the β-galactosidase in living cells.The as-prepared probe exhibits two emission peaks at 490 nm and 530 nm,respectively,and the ratio of fluorescence intensities from the two emission peaks could be utilized to monitor the β-galactosidase.This present ratiometric fluorescent probe is,therefore,very promising for effective,sensitive,and selective detection of the β-galactosidase in living cells.