An introduction to nonlinear programming—I: Necessary and sufficient conditions

Parameter optimization problems arise in a wide variety of applications. The importance of the general problem has led to the investigation and development of the field of nonlinear programming and of the special classes of these problems such as linear programming. The study of these problems has reached a sophisticated level and an extensive literature exists, including a number of excellent textbooks. In this and in subsequent articles, the basic results of nonlinear programming are reviewed, developed, and discussed. No attempt is made here to survey the vast literature on the subject but sufficient references are included to provide the reader with a basis for a more detailed study. It is hoped that this series of tutorial articles will make the literature more accessible and will provide a useful perspective on the current status of the field. In this first article, the conditions which a solution must satisfy are discussed. To a lesser extent, conditions are examined which, when satisfied, ensure that a solution has been obtained. The discussion in this article of necessary and sufficient conditions for an optimum provides a basis for the subsequent examination of algorithms which can be used to determine the solution of parameter optimization (i.e. nonlinear programming) problems.     

Field assessment of induction motor efficiency through air-gaptorque

Induction motors are the most popular motors used in industry. This paper further suggests the use of the air-gap torque method (see J.S. Hsu et al., ibid., vol.10, no.3, p.471-7, 1995) to evaluate their efficiency and load changes. The fundamental difference between Method E and the air-gap torque method is discussed. Efficiency assessments conducted on induction motors under various conditions show the accuracy and potential of the air-gap torque method     

Letter: Significance of plasma copper and caeruloplasmin concentrations in rheumatoid arthritis

Experiments were conducted on rats. It was shown that sodium oxybutyrate depressed the escape response to punishment of the partner and motivated aggression in much lower doses than the defence conditioned reflex and unmotivated aggression, prevented negative consequences of fear and rage reactions; it also normalized conditioned reflexes in neurotic rats, this pointing to its marked tranquillizing action.     

Ablation of bcl-2 gene expression decreases the numbers of oocytes and primordial follicles established in the post-natal female mouse gonad

Oocyte loss, either directly through attrition (germ cell death) or indirectly through follicular atresia (somatic or granulosa cell death), is a fundamental event associated with defining the time of normal or premature reproductive senescence in females. Although apoptosis has been reported to function as the underlying mechanism responsible for death of both germ cells and somatic cells in the ovary, the final molecular steps which commit ovarian cells to death have not been fully elucidated. To examine if death repressor activity of the bcl-2 gene product is important for germ cell survival, we conducted studies using a Bcl-2 loss-of-function (bcl-2 -/-) transgenic mouse model. Histological analyses revealed that ovaries collected from bcl-2 -/- mice possessed numerous aberrantly formed primordial follicle-like structures containing a single layer of granulosa cells without an oocyte. Additionally, the total number of primordial follicles present which contained a healthy oocyte was markedly reduced in bcl-2 -/- mice as compared to heterozygote (bcl-2 -/+) or wild-type (bcl-2 +/+) mice, suggesting that expression of the bcl-2 death repressor gene is critical for endowment of a normal complement of germ cells and primordial follicles in the mammalian ovary.     

An introduction to nonlinear programming—IV Numerical methods for constrained minimization

In this paper, we consider the problem of determining the numerical solution of constrained minimization problems. This discussion complements the theoretical development regarding the nature of the solution of the general nonlinear programming problem that was presented in Part I of this series of articles. As in our earlier discussion, the objective of this article is to review basic ideas and to illustrate the application of the ideas by describing specific computational algorithms. Thus, we discuss a variety of algorithms but not always in their greatest detail. References are provided for more detailed expositions and for generalizations and extensions of the basic algorithms. Attention is given first to the solution of problems with linear constraints. Then, approximation methods that reduce nonlinearly constrained problems to a sequence of linear programming problems are described. Finally, the discussion is completed by describing methods that reduce nonlinearly constrained problems to a sequence of unconstrained problems. Much of the discussion of specific algorithms draws upon the results presented in Parts II and III of this series.     

Sexual assault and mental disorders in a community population.

In a cross-sectional probability survey of 3,132 household adults representing two Los Angeles communities, lifetime diagnoses of nine major mental disorders were compared between those who reported that they had been sexually assaulted at some time in their lives and those who reported no sexual assault. Sexual assault predicted later onset of major depressive episodes, substance use disorders, and anxiety disorders. Those who were assaulted in childhood were more likely than those first assaulted in adulthood to report the subsequent development of a mental disorder. Demographic characteristics of gender, age, Hispanic ethnic background, and education, however, were generally unrelated to the probability of developing any specific disorder after being assaulted. Finally, major depression, drug abuse or dependence, antisocial personality, and phobia were all associated with a higher probability of subsequent sexual assault. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Bcl-2-deficient mice demonstrate fulminant lymphoid apoptosis, polycystic kidneys, and hypopigmented hair

bcl-2-/-mice complete embryonic development, but display growth retardation and early mortality postnatally. Hematopoiesis including lymphocyte differentiation is initially normal, but thymus and spleen undergo massive apoptotic involution. Thymocytes require an apoptotic signal to manifest accelerated cell death. Renal failure results from severe polycystic kidney disease characterized by dilated proximal and distal tubular segments and hyperproliferation of epithelium and interstitium. bcl-2-/-mice turn gray with the second hair follicle cycle, implicating a defect in redox-regulated melanin synthesis. The abnormalities in these loss of function mice argue that Bcl-2 is a death repressor molecule functioning in an antioxidant pathway.