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  2. Percoll - Wikipedia

    en.wikipedia.org/wiki/Percoll

    Percoll was previously used in assisted reproductive technology (ART) to select sperm from semen by density gradient centrifugation, for use in techniques such as in vitro fertilization or intrauterine insemination. However, in 1996, Pharmacia sent out a letter to laboratories stating that Percoll should be used for research purposes only, not ...

  3. Conjugate gradient method - Wikipedia

    en.wikipedia.org/wiki/Conjugate_gradient_method

    Conjugate gradient, assuming exact arithmetic, converges in at most n steps, where n is the size of the matrix of the system (here n = 2). In mathematics, the conjugate gradient method is an algorithm for the numerical solution of particular systems of linear equations, namely those whose matrix is positive-semidefinite.

  4. Differential centrifugation - Wikipedia

    en.wikipedia.org/wiki/Differential_centrifugation

    Differences between differential and density gradient centrifugation [ edit ] The difference between differential and density gradient centrifugation techniques is that the latter method uses solutions of different densities (e.g. sucrose , Ficoll , Percoll ) or gels through which the sample passes.

  5. Gradient descent - Wikipedia

    en.wikipedia.org/wiki/Gradient_descent

    Gradient descent with momentum remembers the solution update at each iteration, and determines the next update as a linear combination of the gradient and the previous update. For unconstrained quadratic minimization, a theoretical convergence rate bound of the heavy ball method is asymptotically the same as that for the optimal conjugate ...

  6. Biconjugate gradient method - Wikipedia

    en.wikipedia.org/wiki/Biconjugate_gradient_method

    In mathematics, more specifically in numerical linear algebra, the biconjugate gradient method is an algorithm to solve systems of linear equations A x = b . {\displaystyle Ax=b.\,} Unlike the conjugate gradient method , this algorithm does not require the matrix A {\displaystyle A} to be self-adjoint , but instead one needs to perform ...

  7. Proximal gradient method - Wikipedia

    en.wikipedia.org/wiki/Proximal_gradient_method

    Proximal gradient methods are a generalized form of projection used to solve non-differentiable convex optimization problems. A comparison between the iterates of the projected gradient method (in red) and the Frank-Wolfe method (in green). Many interesting problems can be formulated as convex optimization problems of the form

  8. Signal Protocol - Wikipedia

    en.wikipedia.org/wiki/Signal_Protocol

    The Signal Protocol (formerly known as the TextSecure Protocol) is a non-federated cryptographic protocol that provides end-to-end encryption for voice and instant messaging conversations. [2] The protocol was developed by Open Whisper Systems in 2013 [ 2 ] and was introduced in the open-source TextSecure app, which later became Signal .

  9. Diffusive gradients in thin films - Wikipedia

    en.wikipedia.org/wiki/Diffusive_gradients_in...

    A photo of a disassembled DGT device, showing piston and cap. The device in this picture has been fitted with activated carbon for assimilating gold and/or bisphenols.. The most commonly used DGT device is a plastic "piston-type" probe, and comprises a cylindrical polycarbonate base and a tight-fitting, circular cap with an opening (DGT window).