3,588 research outputs found
Mesh-based video coding for low bit-rate communications
In this paper, a new method for low bit-rate content-adaptive mesh-based video coding is proposed. Intra-frame coding of this method employs feature map extraction for node distribution at specific threshold levels to achieve higher density placement of initial nodes for regions that contain high frequency features and conversely sparse placement of initial nodes for smooth regions. Insignificant nodes are largely removed using a subsequent node elimination scheme. The Hilbert scan is then applied before quantization and entropy coding to reduce amount of transmitted information. For moving images, both node position and color parameters of only a subset of nodes may change from frame to frame. It is sufficient to transmit only these changed parameters. The proposed method is well-suited for video coding at very low bit rates, as processing results demonstrate that it provides good subjective and objective image quality at a lower number of required bits
Drinking water vulnerability to climate change and alternatives for adaptation in coastal South and South East Asia
Integration of aquifer geology, groundwater flow and arsenic distribution in deltaic aquifers - A unifying concept
Groundwater arsenic (As) presents a public health risk of great magnitude in densely populated Asian delta regions, most acutely in the Bengal Basin (West Bengal, India and Bangladesh). Research has focused on the sources, mobilisation, and heterogeneity of groundwater As, but a consistent explanation of As distribution from local to basin scale remains elusive. We show for the Bengal Aquifer System that the numerous, discontinuous silt‐clay layers together with surface topography impose a hierarchical pattern of groundwater flow, which constrains As penetration into the aquifer and controls its redistribution towards discharge zones, where it is re‐sequestered to solid phases. This is particularly so for the discrete periods of As release to groundwater in the shallow subsurface associated with sea level high‐stand conditions of Quaternary inter‐glacial periods. We propose a hypothesis concerning groundwater flow (Silt‐clay layers Impose Hierarchical groundwater flow patterns constraining Arsenic progression [SIHA]), which links consensus views on the As source and history of sedimentation in the basin to the variety of spatial and depth distributions of groundwater As reported in the literature. SIHA reconciles apparent inconsistencies between independent, in some cases contrasting, field observations. We infer that lithological and topographic controls on groundwater flow, inherent to SIHA, apply more generally to deltaic aquifers elsewhere. The analysis suggests that groundwater As may persist in the aquifers of Asian deltas over thousands of years, but in certain regions, particularly at deeper levels, As will not exceed low background concentrations unless groundwater flow systems are short‐circuited by excessive pumping
Impact of climate change and land use on groundwater salinization in southern Bangladesh-implications for other Asian deltas
Pervasive salinity in soil and water is affecting agricultural yield and the health of millions of delta dwellers in Asia. This is also being exacerbated by climate change through increases in sea level and tropical storm surges. One consequence of this has been a widespread introduction of salt water shrimp farming. Here, we show, using field data and modeling, how changes in climate and land use are likely to result in increased salinization of shallow groundwater in SE Asian mega-deltas. We also explore possible adaptation options. We find that possible future increase of episodic inundation events, combined with salt water shrimp farming, will cause rapid salinization of groundwater in the region making it less suitable for drinking water and irrigation. However, modified land use and water management practices can mitigate the impacts on groundwater, as well as the overlying soil, from future salinization. The study therefore provides guidance for adaptation planning to reduce future salinization in Asian deltas
Regional circulatory distribution of novel cardiac bio-markers and their relationships with haemodynamic measurements.
© 2016 Elsevier Ireland Ltd. All rights reserved.Background Regional sampling may identify sites of production or removal of novel biomarkers in the circulation; their relationship to haemodynamic measurements may clarify their association with the pathophysiology of heart failure. Methods Samples were obtained from up to eight circulatory sites from 22 patients with left ventricular dysfunction undergoing elective cardiac catheterisation. The plasma concentrations (PC) of six biomarkers [mid-regional pro-atrial natriuretic peptide (MR-proANP), C-terminal pro-endothelin-1 (CT-proET-1), mid-regional pro-adreno-medullin (MR-proADM), high sensitivity pro-calcitonin (hsPCT), copeptin and galectin-3 (Gal-3)] were measured. Results Plasma concentrations of MR-proANP were highest in the pulmonary artery (PA) and left ventricle, suggesting myocardial production. Lower concentrations of copeptin, CT-proET-1, MR-proADM and hsPCT were found in the supra-renal inferior vena cava (SRIVC) sample suggesting renal extraction. Plasma concentrations of Galectin-3 varied little by sampling site. Plasma concentrations of MR-proANP (R = 0.69, P = 0.002), MR-proADM (R = 0.51, P = 0.03), CT-proET-1 (R = 0.60, P = 0.009) and Copeptin (R = 0.47, P < 0.05) measured from PA samples correlated with PA systolic pressure. There was no relation between any measured marker and cardiac index. Conclusions Regional sampling shows variation in the plasma concentration of various novel peptides that provides clues to sites of net production and removal. Plasma concentrations of several biomarkers were positively correlated with pulmonary artery pressure
Evaluating Maintainability Prejudices with a Large-Scale Study of Open-Source Projects
Exaggeration or context changes can render maintainability experience into
prejudice. For example, JavaScript is often seen as least elegant language and
hence of lowest maintainability. Such prejudice should not guide decisions
without prior empirical validation. We formulated 10 hypotheses about
maintainability based on prejudices and test them in a large set of open-source
projects (6,897 GitHub repositories, 402 million lines, 5 programming
languages). We operationalize maintainability with five static analysis
metrics. We found that JavaScript code is not worse than other code, Java code
shows higher maintainability than C# code and C code has longer methods than
other code. The quality of interface documentation is better in Java code than
in other code. Code developed by teams is not of higher and large code bases
not of lower maintainability. Projects with high maintainability are not more
popular or more often forked. Overall, most hypotheses are not supported by
open-source data.Comment: 20 page
A partially coupled hydro-mechanical analysis of the Bengal Aquifer System under hydrological loading
The coupled poro-mechanical behaviour of geologic-fluid systems is fundamental to numerous processes in structural geology, seismology, and geotechnics, but is frequently overlooked in hydrogeology. Substantial poro-mechanical influences on groundwater head have recently been highlighted in the Bengal Aquifer System, however, driven by terrestrial water loading across the Ganges–Brahmaputra–Meghna floodplains. Groundwater management in this strategically important fluvio-deltaic aquifer, the largest in southern Asia, requires a coupled hydro-mechanical approach which acknowledges poroelasticity. We present a simple partially coupled, 1-D poroelastic model of the Bengal Aquifer System, and explore the poro-mechanical responses of the aquifer to surface boundary conditions representing hydraulic head and mechanical load under three modes of terrestrial water variation. The characteristic responses, shown as amplitude and phase of hydraulic head in depth profile and of ground surface deflection, demonstrate (i) the limits to using water levels in piezometers to indicate groundwater recharge, as conventionally applied in groundwater resources management; (ii) the conditions under which piezometer water levels respond primarily to changes in the mass of terrestrial water storage, as applied in geological weighing lysimetry; (iii) the relationship of ground surface vertical deflection with changes in groundwater storage; and (iv) errors of attribution that could result from ignoring the poroelastic behaviour of the aquifer. These concepts are illustrated through application of the partially coupled model to interpret multi-level piezometer data at two sites in southern Bangladesh. There is a need for further research into the coupled responses of the aquifer due to more complex forms of surface loading, particularly from rivers
Multi-domain Software Defined Networking: Research status and challenges
A key focus of the transition to next generation computer networking is to improve management of network services thereby enhancing traffic control and flows while simplifying higher-level functionality. Software-defined networking (SDN) is an approach that is being developed to facilitate next generation computer networking by decoupling the traffic control system from the underlying traffic transmission system. SDN offers programmability in network services by separating the control plane from the data plane within network devices and providing programmability for network services. Enhanced connectivity services across the global digital network require a multi-domain capability. This paper presents a review of the current research status in SDN and multi-domain SDN, focusing on OpenFlow protocol, and its future related challenges
MALAT1 Gene Expression in Diabetic Patients with or without Nephropathy
Background: One of the main causes of end-stage renal disease worldwide is diabetic nephropathy, a catastrophic microvascular sequel of diabetes. The pathophysiology of DN must thus be urgently investigated in order to develop appropriate remedies. MALAT1 (Metastasis Associated Lung Adenocarcinoma Transcript 1) is anticipated to be a novel target for the detection and therapy of diabetic nephropathy.
Objectives: This research primarily sought to verify the expression of the circulating lncRNA MALAT1 in peripheral blood mononuclear cells (PBMCs) of diabetic patients, diabetic nephropathy, and healthy controls and assess it's relation to disease related criteria
Patients and methods: 50 diabetic volunteers in this trial sought medical attention at the Outpatient Clinic of Endocrinology & DM at Sohag University Hospital, between January2022 and June 2022 and compare them with 25 apparently healthy persons. The expression of the lncRNA Malat1 was measured using quantitative real-time PCR (qPCR) in 25 people with diabetes, 25 people with DKD, and 25 healthy controls. The clinical relevance of the observations was then assessed.
Results: As compared to control, LncRNA MALAT1 expression in peripheral blood was substantially higher in the diabetics and DKD groups. Spearman correlation showing significant correlation between RQ and duration of DM as P<0.05, also showing significant correlation between RQ and A/C ratio as P<0.05, there was positive moderate correlation between RQ and HBA1C and showing significant negative correlation between RQ and eGFR as P<0.05.
Conclusion: The best technique to identify diabetic nephropathy may be to combine the detection of urine ACR, serum creatinine, and eGFR with diabetes mellitus. LncRNA Malat1 is substantially expressed in DKD patients compared to diabetics and an apparently healthy group
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