Minutes-duration optical flares with supernova luminosities

In recent years, certain luminous extragalactic optical transients have been observed to last only a few days1. Their short observed duration implies a different powering mechanism from the most common luminous extragalactic transients (supernovae), whose timescale is weeks2. Some short-duration transients, most notably AT2018cow (ref. 3), show blue optical colours and bright radio and X-ray emission4. Several AT2018cow-like transients have shown hints of a long-lived embedded energy source5, such as X-ray variability6,7, prolonged ultraviolet emission8, a tentative X-ray quasiperiodic oscillation9,10 and large energies coupled to fast (but subrelativistic) radio-emitting ejecta11,12. Here we report observations of minutes-duration optical flares in the aftermath of an AT2018cow-like transient, AT2022tsd (the ‘Tasmanian Devil’). The flares occur over a period of months, are highly energetic and are probably nonthermal, implying that they arise from a near-relativistic outflow or jet. Our observations confirm that, in some AT2018cow-like transients, the embedded energy source is a compact object, either a magnetar or an accreting black hole

Spectrometric determination of clinically relevant fatty acids in the blood serum

The content of fatty acid (FA) triglycerides in food and biological media is predicting traditionally using gas and liquid chromatographic methods. Named techniques aren’t available for clinical labs due to their complexity. So, our objective was to develop the method and apparatus for rapid assay of a few clinically important FA as the saturated palmitic, mono unsaturated oleic and others in serum using near infrared spectrometer. As a result, the applicability of the FT spectrometer in the wavelength range of 0.9 -1.8 μ to analyze these FA in serum without sample preparation was confirmed. Besides, measurement specifications were determined and a correlations of the absorption spectra and contents of total triglycerides and cholesterol, palmitic, oleic, linoleic and arachidonic FA in serum were establishe

Partial possibilistic regression path modeling

This paper introduces structural equation modeling for imprecise data, which enables evaluations with different types of uncertainty. Coming under the framework of variance-based analysis, the proposed method called Partial Possibilistic Regression Path Modeling (PPRPM) combines the principles of PLS path modeling to model the network of relations among the latent concepts, and the principles of possibilistic regression to model the vagueness of the human perception. Possibilistic regression defines the relation between variables through possibilistic linear functions and considers the error due to the vagueness of human perception as reflected in the model via interval-valued parameters. PPRPM transforms the modeling process into minimizing components of uncertainty, namely randomness and vagueness. A case study on the motivational and emotional aspects of teaching is used to illustrate the method