The "spurious regression problem" in the classical regression model framework

I analyse the "spurious regression problem" from the Classical Regression Model (CRM) point of view. Simulations show that the autocorrelation corrections suggested by the CRM, e.g., feasible generalised least squares, solve the problem. Estimators are unbiased, consistent, efficient and deliver correctly sized tests. Conversely, first differencing the data results in inefficiencies when the autoregressive parameter in the error process is less than one. I offer practical recommendations for handling cases suspected to be in the "spurious regression" class.spurious regression, classical regression model, generalised least squares, autocorrelation corrections

Forecasting aggregate stock returns using the number of initial public offerings as a predictor

Large number of Initial Public Offerings (IPOs) reliably predicts subsequent low equally weighted aggregate stock returns and the return differential between small and big firms, both in-sample and out-of-sample. The forecasting patterns are consistent with a behavioral story featuring investor sentiment and limits to arbitrage.Initial Public Offerings

Investigation of clouds spatial distribution using ground-based lidar

Certain investigations of spatial distribution of clouds by employing ground based lidar are presented. The great changeability is one of the main properties of the clouds in the boundary layer. As a result, their optical properties change rapidly which complicates the modeling of cloud evolution. Suitable equipped lidars are widely used for diagnostics of the clouds via a number of scattering and absorption processes. In particular, lidar can provide information on the distribution of meteorological parameters and of the other important cloud characteristics both in vertical and horizontal directions. Herein the time and spatial distribution of the aerosol backscattering coefficient of S sub t and S sub c type clouds are investigated by means of a correlation analysis of the lidar obtained data provided from several arbitrary directions and heights

Self-Motion Versus Environmental-Motion Perception Following Rotational Vestibular Stimulation and Factors Modifying Them

Motion perception following rotational vestibular stimulation is described either as a self-motion or as an environmental-motion. The purpose of the present study was to establish frequency of occurrence of both sensations in healthy humans; what other sensations they experience and how factors insinuation and visual cues modify them. Twenty-four healthy subjects were rotated with constant velocity of 80°/s in four combinations of opened and closed eyes during the rotation and after a sudden stop. After the cessation of the rotation they reported their spontaneous or insinuated illusory motion. During spontaneous perception after sudden cessation of rotation and with the subject's eyes open, the illusory sensations of self- and environmental-motion were almost equally presented. There was no simultaneous illusory perception of self-motion and environmental-motion. Insinuation modified the perception of motion; presence or absence of visual cues prior to the cessation of the rotation and the presence or absence of visual cues immediately after the cessation of the rotation changed the motion sensation. There is a gender effect in motion perception. This finding might be of benefit in further exploring the gender difference in the susceptibility to motion sickness

Gender differences in cheating: loss vs gain framing

We use the die-paradigm to study gender differences in cheating behavior. We find that i) both males and females do not cheat in the absence of financial incentives, ii) both males and females cheat (but not maximally) if reports are associated with financial gains or losses, and iii) males and females do not cheat differentially

THE EFFECT OF APPLYING WITH IMMUNOCYTOPHYTE ON THE CONTENT AND CHEMICAL COMPOSITION OF THE ESSENTIAL OIL FROM COMMON BASIL OF ‘TRAKIA’ CULTIVAR

The aim of the study was to establish the effect of the leaf treatments with Immunocytophyte on the content, yield and chemical composition of the essential oil distilled from dry leaf and stems biomass and flower spikes of common basil, ‘Trakia’ cultivar. The experiment was carried out in the period 2007-2009 on the Training-and-Experimental fields of the Agricultural University – Plovdiv, set by the block plot design in four replications, the plot size being 20 m2. The following variants were studied: 1) Control; 2) 0.5 tablet per 50 m2, 3) 1 tablet per 50 m2, 4) 1.5 tablet per 50 m2, applied three times during the vegetation period before flowering of the second-order branches after basic fertilization with 16 kg/da of nitrogen (applied three times) and irrigation to 80-100% of water holding capacity. The results showed that the application of Immunocytophyte had a negative effect on the essential oil content. Nevertheless, higher essential oil yields were obtained in the treated variants thanks to the higher yield of dry matter. The major components of the essential oil distilled from dry leaf and stem biomass and flower spikes are linalool, limonene, methyl chavicol and methyl cinnamate

An intuitionistic fuzzy component based appoach for identifying web usage patterns

An intuitionistic fuzzy component based appoach fo