1,182 research outputs found
Predicting the dissolution kinetics of silicate glasses using machine learning
Predicting the dissolution rates of silicate glasses in aqueous conditions is
a complex task as the underlying mechanism(s) remain poorly understood and the
dissolution kinetics can depend on a large number of intrinsic and extrinsic
factors. Here, we assess the potential of data-driven models based on machine
learning to predict the dissolution rates of various aluminosilicate glasses
exposed to a wide range of solution pH values, from acidic to caustic
conditions. Four classes of machine learning methods are investigated, namely,
linear regression, support vector machine regression, random forest, and
artificial neural network. We observe that, although linear methods all fail to
describe the dissolution kinetics, the artificial neural network approach
offers excellent predictions, thanks to its inherent ability to handle
non-linear data. Overall, we suggest that a more extensive use of machine
learning approaches could significantly accelerate the design of novel glasses
with tailored properties
Idiopathic Fascicular Ventricular Tachycardia
Idiopathic fascicular ventricular tachycardia is an important cardiac arrhythmia with specific electrocardiographic features and therapeutic options. It is characterized by relatively narrow QRS complex and right bundle branch block pattern. The QRS axis depends on which fascicle is involved in the re-entry. Left axis deviation is noted with left posterior fascicular tachycardia and right axis deviation with left anterior fascicular tachycardia. A left septal fascicular tachycardia with normal axis has also been described. Fascicular tachycardia is usually seen in individuals without structural heart disease. Response to verapamil is an important feature of fascicular tachycardia. Rare instances of termination with intravenous adenosine have also been noted. A presystolic or diastolic potential preceding the QRS, presumed to originate from the Purkinje fibers can be recorded during sinus rhythm and ventricular tachycardia in many patients with fascicular tachycardia. This potential (P potential) has been used as a guide to catheter ablation. Prompt recognition of fascicular tachycardia especially in the emergency department is very important. It is one of the eminently ablatable ventricular tachycardias. Primary ablation has been reported to have a higher success, lesser procedure time and fluoroscopy time
Predicting Young's Modulus of Glasses with Sparse Datasets using Machine Learning
Machine learning (ML) methods are becoming popular tools for the prediction
and design of novel materials. In particular, neural network (NN) is a
promising ML method, which can be used to identify hidden trends in the data.
However, these methods rely on large datasets and often exhibit overfitting
when used with sparse dataset. Further, assessing the uncertainty in
predictions for a new dataset or an extrapolation of the present dataset is
challenging. Herein, using Gaussian process regression (GPR), we predict
Young's modulus for silicate glasses having sparse dataset. We show that GPR
significantly outperforms NN for sparse dataset, while ensuring no overfitting.
Further, thanks to the nonparametric nature, GPR provides quantitative bounds
for the reliability of predictions while extrapolating. Overall, GPR presents
an advanced ML methodology for accelerating the development of novel functional
materials such as glasses.Comment: 17 pages, 5 figure
Estimation of sedimentary proxy records together with associated uncertainty
Peer reviewedPublisher PD
Assessment of bycatch and discards associated with bottom trawling along Karnataka coast, India
The quantity of bycatch and discard was estimated from the landings of multiday fishing trawlers (MDF) at fisheries harbours and using the data collected onboard single-day fishing trawlers (SDF) for the period 2001-02. The quantity of bycatch generated by trawling along Kamataka coast was estimated as 56,035 tin 2001 and 52,380 t in 2002 forming 54 % and 48 % of total trawl catch respectively
Stomach contents of cetaceans incidentally caught along Mangalore and Chennai coasts of India
Abstract
The stomachs of 32 individuals of seven cetacean species incidentally caught in gill net and purseseine fisheries along Mangalore and Chennai coasts (India) between 2004 and 2006 were examined. The whole stomach (fore-gut, mid-gut and hind-gut) was examined in all cases. Prey remains (666 prey items comprising six species of teleosts, one crustacean and one squid species) were found in the stomachs of eight individuals (the remaining 24 stomachs were found to be empty). All cetaceans were found to feed mostly on teleosts with wide range of trophic levels. Based on an index that included frequency of occurrence, percentage by number and by weight, the oil sardine Sardinella longiceps was the main prey in the sample. Cetaceans appear to favour both pelagic as well as demersal prey, possibly indicating surface and benthic feeding habits
Record of the rough toothed dolphin Steno bredanensis (G. Cuvier in Lesson, 1828) in Indian seas after 19th century
A specimen of the rare delphinid Steno bredanensis, was washed ashore on 25 August 2008 in Uttara Kannada, south-west
coast of India. This report presents the first stranding record of S. bredanensis in Indian waters after more than 100 years
as the previous confirmed record was only in 1891. There were a few stranding records of this species in 19th century,
but thereafter no single record is available till now. The number of records between the years 1800 and 1900 were only 3.
Earlier works from Indian seas depended on conventional taxonomic approaches which led to misidentification of species.
Skin samples were collected for genetic analysis and the genes of control region (CR) and cytochrome b (cyt b) of MtDNA
were PCR amplified and sequenced. Partial sequences of mtDNA control region and cytochrome b genes were generated
and tested with the reference sequences available in GenBank (NCBI) and the web-based program DNA Surveillance, and
the specimen was confirmed as Steno bredanensis. Amplification of sex Y chromosome gene SRY confirmed the visual
identification of the specimen as a male
Increase Productivity Through Knowledge Management
Increase in competition level requires companies to improve the efficiency of work force use characterized by labor productivity. Professional knowledge of staff and its experience play the key role in it. The results of Extrusion Line operator's working time analysis are performed in this article. The analysis revealed that the reasons of working time ineffective use connected with inadequate information exchange and knowledge management in the company. Authors suggest the way to solve this problem: the main sources of knowledge in engineering enterprise have been defined, the conditions of success and the stages of knowledge management control have been stated
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