Analysis of sediment dynamics in intensively managed landscapes

The flux of fine sediment within agricultural watersheds is an important factor determining the environmental quality of streams and rivers. Human activity has significantly altered the hydrological and biogeochemical cycles within terrestrial and aquatic environments through agricultural intensification, tile drainage installation, and urban development. The study of watershed-scale sediment dynamics is of great value for understanding and predicting the response of sediment dynamics to intensive human impact and is crucial to developing management strategies for reducing the vulnerability of the ecosystem to future changes. The primary objective of this dissertation is to investigate sediment sources, sediment transport, and sediment yield in an intensively managed agricultural landscape. This objective was accomplished by combining of field sampling and measurements, laboratory analysis, sediment fingerprinting study, statistical analysis and modeling exploration in the Upper Sangamon River Basin, Illinois. The relative contributions from cropland, grassland, forested floodplain, upper grazed floodplain, and lower grazed floodplain to the suspended sediment in the stream are evaluated by sediment fingerprinting techniques. The grazed areas of the floodplain are identified as the primary source of fine suspended sediment within the headwaters of the Sangamon River. Erosion of the floodplain both by surface runoff and by streambank erosion contribute to the production of almost all fine sediment sampled within the stream system. The results are consistent both for event and aggregated samples and for large and small events. The fingerprinting results are also consistent with visible and historical evidence of active erosion of grazed areas of floodplain upstream from the in-stream sampling location. Evidence from field reconnaissance and inspection of aerial photography supports the conclusion that cattle grazing plays an important role in accelerating floodplain and streambank erosion. The relationships between rainfall, discharge, and suspended sediment concentration are examined by sediment rating curve approach and hysteresis analysis. Sediment rating curves developed for three sites along the Sangamon River all have a peaked pattern with a transition point at geometric mean of discharge, indicating suspended sediment load in the stream is far below the stream transport capacity during high flows. Spatially, suspended sediment concentrations tend to become more coincident with the seasonality of rainfall and discharge with increasing watershed size and the mean suspended sediment concentration decreases as drainage area increases. Temporally, the SRCs developed for the rising and falling limbs of hydrographs and the four sampling seasons also exhibit the same trends, suggesting that these trends are not scale-dependent. The peaked pattern of sediment rating curve is most apparent in sediment rating curve developed on discharge and sediment data collected in summer, which means the limitation of sediment supply is most significant in summer. Sediment fluxes in modern times and before European settlement is investigated by using a semi-distributed, coupled hydrologic and sediment model. Intensive agricultural activities since European settlement have increased sediment supply and enhanced suspended sediment load in stream, and also influence re-distribution of detached sediment within the system. The percent of sediment supply from each source to the total amount of mobilized sediment significantly changed from 1840s to 2000s, and the agricultural uplands have become the major source of suspended sediment in the stream. The model estimates that sediment supply from uplands increased 11-fold from the 1840s to 2000s, and sediment yield in 2000s is 9 times of that in 1840s. A higher percent of sediment is transported out of the system and deposited in the channel in 2000s than in 1840s. Suspended sediment load has increased more rapidly than floodplain sedimentation. The re-distribution of detached sediment is also influenced by the presence of built levees and extended channel network. With the increased sediment supply and decreased percent of floodplain sedimentation, sediment delivery ratio for the entire watershed only increased 4%. In conclusion, the integrated results from field, statistical and modeling studies advance the knowledge and understanding of sediment supply, delivery, and export in intensively managed landscapes. The findings also inform management strategies aimed at reducing the vulnerability of this landscape to ongoing human impact

Lesion region segmentation via weakly supervised learning

Background: Image-based automatic diagnosis of field diseases can help increase crop yields and is of great importance. However, crop lesion regions tend to be scattered and of varying sizes, this along with substantial intra-class variation and small inter-class variation makes segmentation difficult. Methods: We propose a novel end-to-end system that only requires weak supervision of image-level labels for lesion region segmentation. First, a two-branch network is designed for joint disease classification and seed region generation. The generated seed regions are then used as input to the next segmentation stage where we design to use an encoder-decoder network. Different from previous works that use an encoder in the segmentation network, the encoder-decoder network is critical for our system to successfully segment images with small and scattered regions, which is the major challenge in image-based diagnosis of field diseases. We further propose a novel weakly supervised training strategy for the encoder-decoder semantic segmentation network, making use of the extracted seed regions. Results: Experimental results show that our system achieves better lesion region segmentation results than state of the arts. In addition to crop images, our method is also applicable to general scattered object segmentation. We demonstrate this by extending our framework to work on the PASCAL VOC dataset, which achieves comparable performance with the state-of-the-art DSRG (deep seeded region growing) method. Conclusion: Our method not only outperforms state-of-the-art semantic segmentation methods by a large margin for the lesion segmentation task, but also shows its capability to perform well on more general tasks

Solving a Class of Singular Fifth-Order Boundary Value Problems Using Reproducing Kernel Hilbert Space Method

We use the reproducing kernel Hilbert space method to solve the fifth-order boundary value problems. The exact solution to the fifth-order boundary value problems is obtained in reproducing kernel space. The approximate solution is given by using an iterative method and the finite section method. The present method reveals to be more effective and convenient compared with the other methods

The changes of cardiac energy metabolism with sodium-glucose transporter 2 inhibitor therapy

Background/aimsTo investigate the specific effects of s odium-glucose transporter 2 inhibitor (SGLT2i) on cardiac energy metabolism.MethodsA systematic literature search was conducted in eight databases. The retrieved studies were screened according to the inclusion and exclusion criteria, and relevant information was extracted according to the purpose of the study. Two researchers independently screened the studies, extracted information, and assessed article quality.ResultsThe results of the 34 included studies (including 10 clinical and 24 animal studies) showed that SGLT2i inhibited cardiac glucose uptake and glycolysis, but promoted fatty acid (FA) metabolism in most disease states. SGLT2i upregulated ketone metabolism, improved the structure and functions of myocardial mitochondria, alleviated oxidative stress of cardiomyocytes in all literatures. SGLT2i increased cardiac glucose oxidation in diabetes mellitus (DM) and cardiac FA metabolism in heart failure (HF). However, the regulatory effects of SGLT2i on cardiac FA metabolism in DM and cardiac glucose oxidation in HF varied with disease types, stages, and intervention duration of SGLT2i.ConclusionSGLT2i improved the efficiency of cardiac energy production by regulating FA, glucose and ketone metabolism, improving mitochondria structure and functions, and decreasing oxidative stress of cardiomyocytes under pathological conditions. Thus, SGLT2i is deemed to exert a benign regulatory effect on cardiac metabolic disorders in various diseases.Systematic review registrationhttps://www.crd.york.ac.uk/, PROSPERO (CRD42023484295)

Effects of Wenxin Keli on the Action Potential and L-Type Calcium Current in Rats with Transverse Aortic Constriction-Induced Heart Failure

Objective. We investigated the effects of WXKL on the action potential (AP) and the L-type calcium current (ICa-L) in normal and hypertrophied myocytes. Methods. Forty male rats were randomly divided into two groups: the control group and the transverse aortic constriction- (TAC-) induced heart failure group. Cardiac hypertrophy was induced by TAC surgery, whereas the control group underwent a sham operation. Eight weeks after surgery, single cardiac ventricular myocytes were isolated from the hearts of the rats. The APs and ICa-L were recorded using the whole-cell patch clamp technique. Results. The action potential duration (APD) of the TAC group was prolonged compared with the control group and was markedly shortened by WXKL treatment in a dose-dependent manner. The current densities of the ICa-L in the TAC group treated with 5 g/L WXKL were significantly decreased compared with the TAC group. We also determined the effect of WXKL on the gating mechanism of the ICa-L in the TAC group. We found that WXKL decreased the ICa-L by accelerating the inactivation of the channels and delaying the recovery time from inactivation. Conclusions. The results suggest that WXKL affects the AP and blocked the ICa-L, which ultimately resulted in the treatment of arrhythmias

Capsaicin Protects Mice from Community-Associated Methicillin-Resistant Staphylococcus aureus Pneumonia

BACKGROUND: α-toxin is one of the major virulence factors secreted by most Staphylococcus aureus strains, which played a central role in the pathogenesis of S. aureus pneumonia. The aim of this study was to investigate the impact of capsaicin on the production of α-toxin by community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) strain USA 300 and to further assess its performance in the treatment of CA-MRSA pneumonia in a mouse model. METHODOLOGY/PRINCIPAL FINDINGS: The in vitro effects of capsaicin on α-toxin production by S. aureus USA 300 were determined using hemolysis, western blot, and real-time RT-PCR assays. The influence of capsaicin on the α-toxin-mediated injury of human alveolar epithelial cells was determined using viability and cytotoxicity assays. Mice were infected intranasally with S. aureus USA300; the in vivo protective effects of capsaicin against S. aureus pneumonia were assessed by monitoring the mortality, histopathological changes and cytokine levels. Low concentrations of capsaicin substantially decreased the production of α-toxin by S. aureus USA 300 without affecting the bacterial viability. The addition of capsaicin prevented α-toxin-mediated human alveolar cell (A549) injury in co-culture with S. aureus. Furthermore, the in vivo experiments indicated that capsaicin protected mice from CA-MRSA pneumonia caused by strain USA 300. CONCLUSIONS/SIGNIFICANCE: Capsaicin inhibits the production of α-toxin by CA-MRSA strain USA 300 in vitro and protects mice from CA-MRSA pneumonia in vivo. However, the results need further confirmation with other CA-MRSA lineages. This study supports the views of anti-virulence as a new antibacterial approach for chemotherapy