Insha’s Redescending M-estimator for Robust Regression: A Comparative Study

In this paper we present a new redescending M-estimator “Insha’s estimator” for robust regression and outliers detection that overcomes some drawbacks of other M-estimators for robust regression and outliers detection, such as destruction of the good observations and lack of simplicity in applications. The Ψ-function associated with the proposed estimator attains more linearity in the central section before it redescends, resulting in enhanced efficiency. Moreover the estimator is continuous everywhere and can be written in closed form without the use of an indictor function. The estimator is also applied to a real world example taken from the literature. For the purpose of comparison with other well-known redescending M-estimators extensive simulation study has been carried out. The example and simulation study show that using this estimator all the outliers can be successfully detected and is not affected by outliers

Amelioration of experimental hyperlipidemia in rats by Portulaca oleracea Linn from Kashmir Himalaya

Background: Traditionally, Portulaca oleracea Linn. treats abscesses and dysentery as well as liver disease. Additionally, recent studies have reported its effectiveness as a neuroprotective, analgesic, anti-inflammatory, bronchodilator, anti-cancer, antioxidant, and curative, in addition to its pharmacological effects. Aim and Objective: To assess the phytochemical constituents quantitatively & qualitatively and lipid-lowering potential of different extracts of Portulaca oleracea L. from Kashmir Himalaya. Methods: Portulaca oleracea L. was extracted with chloroform, methanol, and aqueous solvents. Qualitative and quantitative phytochemical screening was carried and antihyperlipidemic activity was evaluated in experimental hyperlipidemic rats fed with cholesterol in coconut oil for 14 days. Results: Chloroform, methanol, and aqueous extracts showed the presence of alkaloids, sapon ins, tannins, cardiac glycosides, terpenes, flavonoids, phenolic compounds, proteins, and carbohydrates. Quantitatively the dried plant powder contains alkaloids 0.72 g%, saponins 1.0 g%, phenolics 1.09 g%, tannins 0.91 g%, carbohydrates 0.53 g%, proteins 0.25 g% and lipids 0.87 g%. The aqueous extract was found to decrease the plasma total cholesterol, triglyceride, low-density lipoprotein-cholesterol, very lowdensity lipoprotein-cholesterol levels, LDL-C/HDL-C ratio and significantly elevated the high-density lipoprotein-cholesterol levels as compared to methanol and chloroform extracts against cholesterol-induced hyperlipidemic rats. Conclusions: The results reveal that the Portulaca oleracea L. from the Kashmir region possesses alkaloids, saponins, phenolics, tannins, carbohydrates, proteins and lipids and aqueous extract of Portulaca oleracea L. at a dose of 200 mg/kg body weight possess highly significant antihyperlipidemic action than methanolic and chloroform extracts at similar doses