273 research outputs found

    Magnitude and Extent of Contaminated Sediment and Toxicity in Chesapeake Bay

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    INTRODUCTION: This report summarizes the results of NOAA's sediment toxicity, chemistry, and benthic community studies in the Chesapeake Bay estuary. As part of the National Status and Trends (NS&T) Program, NOAA has conducted studies to determine the spatial extent and severity of chemical contamination and associated adverse biological effects in coastal bays and estuaries of the United States since 1991. Sediment contamination in U.S. coastal areas is a major environmental issue because of its potential toxic effects on biological resources and often, indirectly, on human health. Thus, characterizing and delineating areas of sediment contamination and toxicity and demonstrating their effect(s) on benthic living resources are viewed as important goals of coastal resource management. Benthic community studies have a history of use in regional estuarine monitoring programs and have been shown to be an effective indicator for describing the extent and magnitude of pollution impacts in estuarine ecosystems, as well as for assessing the effectiveness of management actions. Chesapeake Bay is the largest estuarine system in the United States. Including tidal tributaries, the Bay has approximately 18,694 km of shoreline (more than the entire US West Coast). The watershed is over 165,000 km2 (64,000 miles2), and includes portions of six states (Delaware, Maryland, New York, Pennsylvania, Virginia, and West Virginia) and the District of Columbia. The population of the watershed exceeds 15 million people. There are 150 rivers and streams in the Chesapeake drainage basin. Within the watershed, five major rivers - the Susquehanna, Potomac, Rappahannock, York and James - provide almost 90% of the freshwater to the Bay. The Bay receives an equal volume of water from the Atlantic Ocean. In the upper Bay and tributaries, sediments are fine-grained silts and clays. Sediments in the middle Bay are mostly made of silts and clays derived from shoreline erosion. In the lower Bay, by contrast, the sediments are sandy. These particles come from shore erosion and inputs from the Atlantic Ocean. The introduction of European-style agriculture and large scale clearing of the watershed produced massive shifts in sediment dynamics of the Bay watershed. As early as the mid 1700s, some navigable rivers were filled in by sediment and sedimentation caused several colonial seaports to become landlocked. Toxic contaminants enter the Bay via atmospheric deposition, dissolved and particulate runoff from the watershed or direct discharge. While contaminants enter the Bay from several sources, sediments accumulate many toxic contaminants and thus reveal the status of input for these constituents. In the watershed, loading estimates indicate that the major sources of contaminants are point sources, stormwater runoff, atmospheric deposition, and spills. Point sources and urban runoff in the Bay proper contribute large quantities of contaminants. Pesticide inputs to the Bay have not been quantified. Baltimore Harbor and the Elizabeth River remain among the most contaminated areas in the Unites States. In the mainstem, deep sediment core analyses indicate that sediment accumulation rates are 2-10 times higher in the northern Bay than in the middle and lower Bay, and that sedimentation rates are 2-10 times higher than before European settlement throughout the Bay (NOAA 1998). The core samples show a decline in selected PAH compounds over the past several decades, but absolute concentrations are still 1 to 2 orders of magnitude above 'pristine' conditions. Core data also indicate that concentrations of PAHs, PCBs and, organochlorine pesticides do not demonstrate consistent trends over 25 years, but remain 10 times lower than sediments in the tributaries. In contrast, tri-butyl-tin (TBT) concentrations in the deep cores have declined significantly since it=s use was severely restricted. (PDF contains 241 pages

    An Empirical Analysis of cluster-based routing protocols in wireless sensor network

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    Wireless Sensor Networks (WSNs) are utilized for condition monitoring, developing the board, following animals or goods, social protection, transportation, and house frameworks. WSNs are revolutionizing research. A WSN includes a large number of sensor nodes, or bits, in the application. Bits outfitted with the application\u27s sensors acquire nature data and send it to at least one sink center (in like manner called base stations). This article simulates energy-efficient network initialization strategies using simulation models. First, an overview of network initiation and exploration procedures in wireless ad-hoc networks is provided. The clustering-based routing strategy was selected since it\u27s best for ad-hoc sensor networks. The clustering-based routing techniques used for this study are described below. LEACH, SEP, and Z-SEP are used. MATLAB was used to implement and simulate all routing protocols. All protocols were simulated with various parameters like Number of CHs, Number of Alive Nodes, Number of Dead Nodes, Number of packets to BS, and circumstances to show their functioning and to determine their behavior in different sensor networks

    The Development of India’s Financial Inclusion Agenda—Some Lessons for Pakistan

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    Financial Inclusion has assumed a vital position in the Public Policy discourse of developing economies. Provision of financial services to the otherwise excluded strata of the society enhances their potential to climb the economic ladder of opportunity and prosperity. Access to financial services to the otherwise excluded impacts their quality of life and enables the less privileged to increase and diversify their incomes, improve their social and economic conditions. Due to lack of access to financial services, most poor households have to rely on their meagre savings or money lenders which limit their ability to actively participate and benefit from the development process. The main theoretical arguments that economic theory postulates regarding the failure of financial markets in percolating poor and rural areas are of informational asymmetries, difficulties in contract designing and enforcement, greater transaction costs. The demand side aspects may be low demand for such services, arising from illiteracy, less investment opportunities in rural areas and difficult loan contracts [Basu (2006)]. When households are access constrained with respect to financial services, it becomes one of the important reasons for persisting inequalities. Economic theory suggests that unrelenting inequalities has a negative impact on the long term growth prospects of an economy [World Bank (2007)]. While establishing causality between financial development and economic growth has been quite tedious, with no simple answers, the evidence of a strong link between financial development and economic growth has continued to rise [Gattoo and Akhtar (2014)]. The interest in the financial inclusion discourse across developing and developing world stems from the recognition that a strong and vibrant financial system does not necessarily imply increasing financial to all across the societal divide [Honohan (2003)]

    Design and implementation of a quadruped amphibious robot using duck feet

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    Roaming complexity in terrains and unexpected environments pose significant difficulties in robotic exploration of an area. In a broader sense, robots have to face two common tasks during exploration, namely, walking on the drylands and swimming through the water. This research aims to design and develop an amphibious robot, which incorporates a webbed duck feet design to walk on different terrains, swim in the water, and tackle obstructions on its way. The designed robot is compact, easy to use, and also has the abilities to work autonomously. Such a mechanism is implemented by designing a novel robotic webbed foot consisting of two hinged plates. Because of the design, the webbed feet are able to open and close with the help of water pressure. Klann linkages have been used to convert rotational motion to walking and swimming for the animal's gait. Because of its amphibian nature, the designed robot can be used for exploring tight caves, closed spaces, and moving on uneven challenging terrains such as sand, mud, or water. It is envisaged that the proposed design will be appreciated in the industry to design amphibious robots in the near future. - 2019 by the authors.Faculty of Robotics and Advanced Computing, Qatar Armed Forces-Academic Bridge Program, Qatar Foundation, 24404 Doha, Qatar Faculty of Engineering, Computing and Science, Swinburne University of Technology, 93350 Sarawak, Malaysia Faculty of Computer Engineering Signal and Image Processing Qatar University, 24404 Doha, Qatar Correspondence: [email protected]

    E-Commerce and E-Governance: Technology for Tomorrow on India Reforms- 2020

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    E-commerce and E-governance is vital on India reforms-2020 on Macro growth and Economical sustainability on World. Germany, France, Greece, Europe, Russia, China, Japan, UK and USA are leader of E-commerce and E-governance. India GDP and macro economy is rising over total 50 million world population. It is because of technology sharing, usability, integration, Web application on J2EE, Java Environment, JDE package, easy accessibility, and remote wireless connectivity, 3G, Multimedia and E-governance. India is on Economic reforms 2020 with digitization and online marketing, e- commerce, ERP and web application. E-commerce is revolutionary in all industries, commercial and professional exchange of ideas and commercialisation. The E-commerce policy 2010-11 has be supportive to the right of consumer and seller for exchange of ideas, goods, and services in B2B, B2C, e-retailing, and e-banking application. The trends in e-commerce are increasing by 21% in all states for online payment, policy update, e-filling, estate business

    Synthetic oligosaccharides can replace animal-sourced low–molecular weight heparins

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    Full-sized and low–molecular weight heparins are widely used to treat a variety of clotting disorders. Although low–molecular weight heparins are safer and more convenient to use than full-size heparin, they are still animal-derived products that present a risk of contamination and supply chain interruptions and are limited with respect to standardization and reversibility of anticoagulation. A method developed by Xu et al . offers a potential alternative to animal-sourced heparins in the form of a chemical synthesis process that can be scaled up to produce heparin dodecasaccharides with reversible activity in adequate quantities for potential therapeutic use

    A Database Study of Visual Outcomes and Intraoperative Complications of Postvitrectomy Cataract Surgery

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    PURPOSE: To analyze the visual outcomes and rate of intraoperative complications of phacoemulsification surgery after prior pars plana vitrectomy (PPV). DESIGN: Retrospective, multicenter database study. PARTICIPANTS: Eyes that underwent phacoemulsification between June 2005 and March 2015 at 8 sites in the United Kingdom. METHODS: Study eyes were classified as vitrectomized (prior PPV group) or nonvitrectomized (reference group) depending on the vitreous state at the time of cataract surgery. Eyes with multiple intraocular surgeries or history of ocular diseases known to cause cataract progression or increased risk of intraoperative complications during phacoemulsification were excluded. MAIN OUTCOME MEASURES: Logarithm of the minimum angle of resolution (logMAR) visual acuity (VA), rate of intraoperative complications, and time interval to cataract surgery. RESULTS: Eyes in the prior PPV group (n = 2221) had worse preoperative logMAR VA (0.96±0.60 vs. 0.62±0.52, P \u3c 0.0001), were from younger patients, and had longer axial lengths than the nonvitrectomized group (n = 136 533). At all postoperative time points measured up to 24 weeks, mean vision was poorer in the prior PPV group (0.41±0.47 vs. 0.17±0.29 at 4-12 weeks, P \u3c 0.0001) and a smaller proportion of eyes achieved postoperative VA ≤0.30 logMAR (Snellen, ≥20/40) (60.8% vs. 86.5% at 4-12 weeks, P \u3c 0.0001). The rate of posterior capsular rupture was not different between the prior PPV (1.5%) and the nonvitrectomized (1.7%) groups, but the incidences of zonular dialysis (1.3% vs. 0.6%) and dropped nuclear fragments (0.6% vs. 0.2%) were higher in the prior PPV group (P \u3c 0.0001). The mean time interval between PPV and cataract surgery was 399 days. CONCLUSIONS: We found a significant improvement in VA with postvitrectomy cataract surgery. However, compared with eyes without prior PPV, there was a worse mean postoperative vision of 0.2 logMAR units, a higher rate of zonular dialysis and dropped nuclear fragments, and a similar rate of posterior capsule rupture

    Pulmonary metastasectomy versus continued active monitoring in colorectal cancer (PulMiCC): a multicentre randomised clinical trial

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    BACKGROUND: Lung metastasectomy in the treatment of advanced colorectal cancer has been widely adopted without good evidence of survival or palliative benefit. We aimed to test its effectiveness in a randomised controlled trial (RCT). METHODS: Multidisciplinary teams in 13 hospitals recruited participants with potentially resectable lung metastases to a multicentre, two-arm RCT comparing active monitoring with or without metastasectomy. Other local or systemic treatments were decided by the local team. Randomisation was remote and stratified by site with minimisation for age, sex, primary cancer stage, interval since primary resection, prior liver involvement, the number of metastases, and carcinoembryonic antigen level. The central Trial Management Group were blind to patient allocation until completion of the analysis. Analysis was on intention to treat with a margin for non-inferiority of 10%. RESULTS: Between December 2010 and December 2016, 65 participants were randomised. Characteristics were well-matched in the two arms and similar to those in reported studies: age 35 to 86 years (interquartile range (IQR) 60 to 74); primary resection IQR 16 to 35 months previously; stage at resection T1, 2 or 3 in 3, 8 and 46; N1 or N2 in 31 and 26; unknown in 8. Lung metastases 1 to 5 (median 2); 16/65 had previous liver metastases; carcinoembryonic antigen normal in 55/65. There were no other interventions in the first 6 months, no crossovers from control to treatment, and no treatment-related deaths or major adverse events. The Hazard ratio for death within 5 years, comparing metastasectomy with control, was 0.82 (95%CI 0.43, 1.56). CONCLUSIONS: Because of poor and worsening recruitment, the study was stopped. The small number of participants in the trial (N = 65) precludes a conclusive answer to the research question given the large overlap in the confidence intervals in the proportions still alive at all time points. A widely held belief is that the 5-year absolute survival benefit with metastasectomy is about 35%: 40% after metastasectomy compared to < 5% in controls. The estimated survival in this study was 38% (23-62%) for metastasectomy patients and 29% (16-52%) in the well-matched controls. That is the new and important finding of this RCT. TRIAL REGISTRATION: ClinicalTrials.gov, ID: NCT01106261. Registered on 19 April 2010
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