A Cost Model for a Fingered Join Operator in Relational Query Plans

We introduce the finger aware cursor operator for relational join queries. It scans a list of tuples in a finger enabled manner when a nested loop join operation is performed. Using this scan operation, we improve the performance of nested loop join when compared to when compared to conventional scan. To quantify the improvement in performance using fingered scan, a statistic named runs that quantifies the degree of randomness in a list of records is introduced. This statistic is vital in assessing the performance improvement achieved using fingered scan. Using runs statistic as a key ingredient, we develop a cost model that can assign a cost value to the join operation based on underlying fingered scan. We then develop a cost formula and evaluate the cost model against a simulated data set. We show that conventional System R cost model is not sufficient to capture the performance improvement. We then evaluate using the new cost formula and show that it predicts the cost of join operation correctly

Highly sensitive poly(3,4-ethylenedioxythiophene) modified electrodes by electropolymerisation in deep eutectic solvents

Deep eutectic solvents are evaluated as media for the electropolymerisation of 3,4-ethylenedioxythiophene (EDOT) for the first time. PEDOT modified glassy carbon electrodes (GCEs) were characterised by cyclic voltammetry, electrochemical impedance spectroscopy and scanning electron microscopy. PEDOT modified GCEs prepared from choline chloride–urea (reline) and choline chloride–ethylene glycol (ethaline) exhibited interesting electrocatalytic and morphological characteristics. Fixed potential sensing of ascorbate at 0.0 V showed a greater electrocatalytic effect, significantly higher sensitivity and lower detection limit than at hitherto reported PEDOT modified electrodes

Left Ventricular Flow Analysis: Recent Advances in Numerical Methods and Applications in Cardiac Ultrasound

The left ventricle (LV) pumps oxygenated blood from the lungs to the rest of the body through systemic circulation. The efficiency of such a pumping function is dependent on blood flow within the LV chamber. It is therefore crucial to accurately characterize LV hemodynamics. Improved understanding of LV hemodynamics is expected to provide important clinical diagnostic and prognostic information. We review the recent advances in numerical and experimental methods for characterizing LV flows and focus on analysis of intraventricular flow fields by echocardiographic particle image velocimetry (echo-PIV), due to its potential for broad and practical utility. Future research directions to advance patient-specific LV simulations include development of methods capable of resolving heart valves, higher temporal resolution, automated generation of three-dimensional (3D) geometry, and incorporating actual flow measurements into the numerical solution of the 3D cardiovascular fluid dynamics

Chemically modified graphene and nitrogen-doped graphene: electrochemical characterisation and sensing applications

Functionalised graphene (G) and nitrogen doped graphene (NG) nanomaterials are excellent candidates for electrocatalytic sensing of biomolecules and for developing biosensors, due to their unique physicochemical and electronic properties. Electrochemical characterisation and comparison of basic or acidic functionalised G and NG has been carried out, as well as of composite materials based on NG with the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) and the redox polymer poly(neutral red) by cyclic voltammetry and electrochemical impedance spectroscopy. Electroactive areas and heterogeneous electron transfer constant, of the GCE modified with the graphene derivatives have been evaluated, in order to choose the best material for electrode modification. The NG modified GCE enabled excellent electrocatalytic regeneration of the enzyme cofactors β-nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD), underlining the applicability of NG for the development of new sensitive biosensors

Abandonment of fibreglass reinforced plastic fishing boats in Kerala, India, and chemical emissions arising from their burning

Little information exists on the fate and impacts of boats constructed of fibreglass reinforced plastic (FRP) once they reach their end-of-life. In this study, the number of abandoned fishing boats constructed of FRP or constructed of plywood-wood and sheathed by FRP has been determined along the coast of Kerala, India, and chemical emissions have been estimated when boats are burned as a means of disposal. A total of 292 abandoned boats were observed across eight coastal transects constructed around selected landing centres, with abandonment ranging from 13 to 48 per km (average = 29 km-1). This results in the generation of 1420 kg of FRP debris (glass mat and epoxy resin) per km of coastline. A controlled combustion experiment, simulating open burning, revealed that 63% of original boat mass is emitted to the atmosphere, with the remainder forming a burnt residue. Total concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans emitted and remaining were found to be 2.6 ng Nm-3 and 249.6 μg kg-1, respectively, with respective calculated toxicity equivalence (TEQ) levels of 437.6 pg TEQ Nm-3 in air emissions and 26.6 μg TEQ kg-1 in the residue. These figures are equivalent to the total emission from FRP boat burning of about 17,000 μg TEQ t-1. Burning also generates significant quantities of potentially toxic metals, with resulting concentrations of Co, Cr and Cu close to or exceeding soil guideline values. The study calls for a greater awareness of the impacts arising from boat abandonment and burning amongst fishermen, and guidelines or regulatory protocols regarding safe and sustainable boat disposal or recycling