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  • mathematical programming  (3)
  • parameter optimization  (3)
  • Lamellar whorls  (2)
  • Springer  (6)
  • American Geophysical Union (AGU)
  • 1975-1979  (6)
Collection
Keywords
Publisher
  • Springer  (6)
  • American Geophysical Union (AGU)
Years
  • 1975-1979  (6)
Year
  • 1
    Electronic Resource
    Electronic Resource
    Proliferation of lamellar whorls in arcuate neurons of the hypothalamus of male rats treated with estradiol benzoate or cyproterone acetate (1977)
    Springer
    Cell & tissue research 182 (1977), S. 537-540 
    Details
    ISSN: 1432-0878
    Keywords: Lamellar whorls ; Arcuate nucleus ; Hypothalamus ; Estradiol benzoate ; Cyproterone acetate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The arcuate nucleus of the hypothalamus (AH) of male rats which had been treated either with estradiol benzoate (E2B) or cyproterone acetate (CPA) was examined ultrastructurally for the presence of whorls of endoplasmic reticulum. The incidence of whorl containing neurons (WCN) was 2–4 times higher in the AH of animals treated for 2–3 weeks with E2B or for 2 weeks with CPA than in the AH of oil treated controls. CPA is a powerful anti-androgen while E2B acts both peripherally and centrally to limit testosterone production. These findings, together with previous evidence that whorls proliferate in AH of male rats deprived of androgen by morphine treatment or castration, suggest that steroid feedback (androgen alone or both androgen and estrogen) plays an important role in AH whorl proliferation. The possibility that WCN may be LH-RH containing neurons is suggested by the close correspondence between the number and location of WCN within AH as determined in this study and the distribution of LH-RH containing cells reported by others.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00219835
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  • 2
    Electronic Resource
    Electronic Resource
    Proliferation of lamellar whorls in arcuate neurons of the hypothalamus of castrated and morphine-treated male rats (1976)
    Springer
    Cell & tissue research 171 (1976), S. 277-284 
    Details
    ISSN: 1432-0878
    Keywords: Arcuate nucleus ; LH-RH ; Testosterone ; Morphine ; Lamellar whorls
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A comprehensive ultrastructural examination of one cross-sectional level (middle 1/3) of the arcuate nucleus of the hypothalamus (AH) of male rats several weeks after castration or after two weeks of morphine treatment confirmed a marked increase in lamellar whorls of endoplasmic reticulum in AH neurons in each group. A comparable incidence of AH whorls was not detected in rats treated with lactose, those treated for only 1–3 days with morphine, or in those given testosterone plus morphine for 2 weeks. It is postulated that the testosterone deficiency following either castration or chronic morphine treatment stimulated the observed increase in AH whorls. A close correspondence was noted between the distribution within the AH of neurons containing whorls and those reported by others to contain luteinizing hormone releasing hormone (LH-RH). The possibility that whorls may be a marker for hypothalamic neurons which play a role in the LH-RH regulatory system warrants further consideration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224653
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  • 3
    Electronic Resource
    Electronic Resource
    Solving the nonlinear least square problem: Application of a general method (1976)
    Springer
    Journal of optimization theory and applications 18 (1976), S. 469-483 
    Details
    ISSN: 1573-2878
    Keywords: Nonlinear least-square problems ; parameter optimization ; penalty function methods ; mathematical programming
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract An algorithm for solving the general nonlinear least-square problem is developed. An estimate for the Hessian matrix is constructed as the sum of two matrices. The first matrix is the usual first-order estimate used by the Gauss method, while the second matrix is generated recursively using a rank-one formula. Test results indicate that the method is superior to the standard Gauss method and compares favorably with other methods, especially for problems with nonzero residuals at the solution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00932656
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  • 4
    Electronic Resource
    Electronic Resource
    An accelerated multiplier method for nonlinear programming (1977)
    Springer
    Journal of optimization theory and applications 21 (1977), S. 137-174 
    Details
    ISSN: 1573-2878
    Keywords: Augmented penalty function ; method of multipliers ; penalty function methods ; nonlinear programming ; mathematical programming
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract This paper describes an accelerated multiplier method for solving the general nonlinear programming problem. The algorithm poses a sequence of unconstrained optimization problems. The unconstrained problems are solved using a rank-one recursive algorithm described in an earlier paper. Multiplier estimates are obtained by minimizing the error in the Kuhn-Tucker conditions using a quadratic programming algorithm. The convergence of the sequence of unconstrained problems is accelerated by using a Newton-Raphson extrapolation process. The numerical effectiveness of the algorithm is demonstrated on a relatively large set of test problems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00932517
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  • 5
    Electronic Resource
    Electronic Resource
    A gradient projection-multiplier method for nonlinear programming (1978)
    Springer
    Journal of optimization theory and applications 24 (1978), S. 523-548 
    Details
    ISSN: 1573-2878
    Keywords: Multiplier method ; gradient projection method ; penalty function methods ; nonlinear programming ; parameter optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract This paper describes a gradient projection-multiplier method for solving the general nonlinear programming problem. The algorithm poses a sequence of unconstrained optimization problems which are solved using a new projection-like formula to define the search directions. The unconstrained minimization of the augmented objective function determines points where the gradient of the Lagrangian function is zero. Points satisfying the constraints are located by applying an unconstrained algorithm to a penalty function. New estimates of the Lagrange multipliers and basis constraints are made at points satisfying either a Lagrangian condition or a constraint satisfaction condition. The penalty weight is increased only to prevent cycling. The numerical effectiveness of the algorithm is demonstrated on a set of test problems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00935298
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  • 6
    Electronic Resource
    Electronic Resource
    An improved penalty function method for solving constrained parameter optimization problems (1975)
    Springer
    Journal of optimization theory and applications 16 (1975), S. 1-24 
    Details
    ISSN: 1573-2878
    Keywords: Penalty-function methods ; mathematical programming ; nonlinear programming ; pseudo Newton-Raphson methods ; parameter optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract An effective algorithm is described for solving the general constrained parameter optimization problem. The method is quasi-second-order and requires only function and gradient information. An exterior point penalty function method is used to transform the constrained problem into a sequence of unconstrained problems. The penalty weightr is chosen as a function of the pointx such that the sequence of optimization problems is computationally easy. A rank-one optimization algorithm is developed that takes advantage of the special properties of the augmented performance index. The optimization algorithm accounts for the usual difficulties associated with discontinuous second derivatives of the augmented index. Finite convergence is exhibited for a quadratic performance index with linear constraints; accelerated convergence is demonstrated for nonquadratic indices and nonlinear constraints. A computer program has been written to implement the algorithm and its performance is illustrated in fourteen test problems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00935620
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