Purdue University

About: Purdue University is a education organization based out in West Lafayette, Indiana, United States. It is known for research contribution in the topics: Population & Heat transfer. The organization has 73219 authors who have published 163563 publications receiving 5775236 citations. The organization is also known as: Purdue & Purdue-West Lafayette.

Shape Discrimination Using Fourier Descriptors

Abstract: Description or discrimination of boundary curves (shapes) is an important problem in picture processing and pattern recognition Fourier descriptors (FD's) have interesting properties in this respect. First, a critical review is given of two kinds of FD's. Some properties of the FD's are given and a distance measure is proposed, in terms of FD's, that measures the difference between two boundarv curves. It is shown how FD's can be used for obtaining skeletons fobjects. Finally, experimental results are given in character recognition and machine parts recognition.

Social Origins of Self-Regulatory Competence

Abstract: This article reviews the social origins of students' development of self-regulatory skill with special emphasis on observational learning through modeling A social cognitive perspective on self-regulation is presented In this view, students' academic competence develops initially from social sources of academic skill and subsequently shifts to self sources in a series of 4 levels: observational, imitative, self-controlled, and self-regulated The effects of models on observers depend in part on perceptions of self-efficacy, or beliefs about one's capabilities to learn or perform designated behaviors Research on social influences is reviewed, and includes factors such as cognitive modeling, coping and mastery models, self-modeling, learning goals, and progress feedback Related theoretical perspectives are discussed along with suggestions for future research

The biology of leptin: a review.

Abstract: Leptin, a 16-kDa protein secreted from white adipocytes, has been implicated in the regulation of food intake, energy expenditure, and whole-body energy balance in rodents and humans. The gene encoding leptin was identified by positional cloning and is the mutation leading to the profound obese phenotype of the ob/ob mouse. Exogenous administration of leptin to ob/ob mice leads to a significant improvement in reproductive and endocrine status as well as reduced food intake and weight loss. The expression and secretion of leptin is highly correlated with body fat mass and adipocyte size. Cortisol and insulin are potent stimulators of leptin expression, and expression is attenuated by beta-adrenergic agonists, cAMP, and thiazolidinediones. The role of other hormones and growth factors in the regulation of leptin expression and secretion is emerging. Leptin circulates specifically bound to proteins in serum, which may regulate its half-life and biological activity. Isoforms of the leptin receptor, members of the interleukin-6 cytokine family of receptors, are found in multiple tissues, including the brain. Many of leptin's effects on food intake and energy expenditure are thought to be mediated centrally via neurotransmitters such as neuropeptide Y. Multiple peripheral effects of leptin have also been recently described, including the regulation of insulin secretion by pancreatic beta cells and regulation of insulin action and energy metabolism in adipocytes and skeletal muscle. Leptin is thought to be a metabolic signal that regulates nutritional status effects on reproductive function. Leptin also plays a major role in hematopoeisis and in the anorexia accompanying an acute cytokine challenge. The profound effects of leptin on regulating body energy balance make it a prime candidate for drug therapies for humans and animals.

Detection of TeV photons from the active galaxy Markarian 421

Abstract: The detection of TeV energy photons from the giant elliptical galaxy Markarian 421 using the Whipple Observatory gamma-ray telescope is reported. The signal has a statistical significance of 6 sigma above background and the flux above 0.5 TeV is 0.3 of that from the Crab Nebula. The source location agrees with the position of Mk 421 within the angular uncertainty of the Whipple instrument.