156,760 research outputs found
Oral History Interview with David T. Lopez, June 27, 2016
No full textDavid T. Lopez was born in Laredo, TX. He attended the University of Texas at Austin, where he became involved as a reporter and editor for the Daily Texan and the Texas Ranger. His involvement in news reporting lead him to work for the Corpus Christi Caller-Times, where he reported on Black and Brown efforts in school desegregation. Attracted by Cesar Chavez and United Farm Workers movement, Lopez would participate in the strikes in the Rio Grande Valley and would report on the repressive tactics of the Texas Rangers as a plaintiff in the Medrano v. Allee lawsuit. He eventually got his law degree at South Texas College of Law in Houston and worked as a field representative for the AFL-CIO. Lopez discusses how he served on the HISD school board, the politics of the Huelga School Strike, how he was one of the first lecturers for the University of Houston Center for Mexican American Studies, and police brutality
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Lino M. Lopez of Denver receives a scholarship check from Colorado State Chairman Joe T. Martinez (photo copy)
No full textLino M. Lopez of Denver receives a scholarship check from Colorado State Chairman Joe T. Martinez
Recommended from our members
Lino M. Lopez of Denver receives a scholarship check from Colorado State Chairman Joe T. Martinez (photograph)
No full textLino M. Lopez of Denver receives a scholarship check from Colorado State Chairman Joe T. Martinez
Congressional Record Tribute: Lopez, T. Joseph
No full textAdmiral Lopez attended the Naval Postgraduate School in Monterey, CA, from 1970 to 1973Mr. SKELTON. Mr. Speaker, I rise today to recognize and honor Admiral T. Joseph Lopez, U.S. Navy, as he prepares to retire upon completion of 39 years of faithful service to our Nation. A native of Powellton, West Virginia, Admiral Lopez entered the United States Navy in September 1959, and was commissioned an Ensign via the Seaman-to-Admiral Program in December 1964. His educational background includes a Bachelor of Arts (Cum Laude) in International Relations, and a Master of Science in Personnel Management. Admiral Lopez is currently the only serving admiral who enlisted, was commissioned through the seaman to admiral program, and currently wears four stars.Approved for public release; distribution is unlimited
One step semi-explicit methods based on the Cayley transform for solving isospectral flows
No full textThis note deals with the numerical solution of the matrix differential system Y′ = [B(t,Y), Y], Y(0) = Y0, t ⩾ 0, where Y0 is a real constant symmetric matrix, B maps symmetric into skew-symmetric matrices, and [B(t,Y),Y] is the Lie bracket commutator of B(t,Y) and Y, i.e. [B(t,Y),Y] = B(t,Y)Y − YB(t,Y). The unique solution of (1) is isospectral, that is the matrix Y(t) preserves the eigenvalues of Y0 and is symmetric for all t (see [1, 5]). Isospectral methods exploit the Flaschka formulation of (1) in which Y(t) is written as Y(t) = U(t)Y0UT(t), for t ⩾ 0, where U(t) is the orthogonal solution of the differential system U′ = B(t, UY0UT)U, U(0) = I, t ⩾ 0, (see [5]). Here a numerical procedure based on the Cayley transform is proposed and compared with known isospectral methods
I servizi socio-educativi nell’era del digitale. Sfide e opportunità
No full textThe pandemic has played a catalyst role in the digitization processes of services and relationships between professionals and people, highlighting the existence of a "minimum technological vital" (Campedelli, Toc-cafondi and Vignani, 2021) which can draw the line between social inclusion and exclusion. The measures introduced to deal with the spread of the virus have imposed rapid transformations and, in just a few weeks, digital technologies have been integrated into all aspects of professional life, showing positive and negative effects (Lopez et al., 2020) . The introduction of numerous platforms, the use of which has exploded during the quarantine, has provided previously overlooked, if not ignored, opportunities to meet and interact with people in different settings. Digital technologies have helped professionals by providing virtual bridges and creating connections. At the same time, they have made it even more evident - through the observation of the negative effects of their absence - the relevance of access to services and its close connection with the success of inclusion paths; the close connection between information and access to health and the protection of rights has become even more evident, and the centrality of the role of telecommunications networks in guaranteeing the performance, even during the health emergency, of some essential public functions (Di Rosa & Tumminelli, 2022)
Congressional Record Tribute: Lopez, T. Joseph
No full textAdmiral Lopez was the only Navy commanding officer to lead a river assault into Cambodia. Lopez was assigned to the Naval Postgraduate School from 1970-73.
Following tours of duty at the Naval Postgraduate SchoolMr. WARNER. Mr. President, I rise today to pay tribute to Admiral Joe Lopez on the occasion of his Change of Command as Commander of Allied Forces, Southern Europe and U.S. Naval Forces, Europe and his retirement from the United States Navy after 39 years of dedicated service to the nation.Approved for public release; distribution is unlimited
Letter, [Author unclear] to Paulina T. Merritt
No full textHandwritten letter to Paulina Merritt from an unknown author, October 1, 1876.
Variable Step-Size Techniques in Continuous Runge-Kutta Methods for Isospectral Dynamical Systems
No full textIn this paper we consider numerical methods for the dynamical system L′ = [B(L), L], L(0) = L0, (*) where L0 is a n × n symmetric matrix, [B(L), L] is the commutator of B(L) and L, and B(L) is a skew-symmetric matrix for each symmetric matrix L. The differential system is isospectral, i.e., L(t) preserves the eigenvalues of L0, for t ≥ 0. The matrix B(L) characterizes the flow, and for special B(·), the solution matrix L(t) tends, as t increases, to a diagonal matrix with the same eigenvalues of L0. In [11] a modification of the MGLRK methods, introduced in [2], has been proposed. These procedures are based on a numerical approximation of the Flaschka formulation of (*) by Runge-Kutta (RK) methods. Our numerical schemes (denoted by EdGLRKs) consist in solving the system (*) by a continuous explicit Runge-Kutta method (CERK) and then performing a single step of a Gauss-Legendre RK method, for the Flaschka formulation of (*), in order to convert the approximation of L(t) to an isospectral solution. The problems of choosing a constant time step or a variable time step strategy are both of great importance in the application of these methods. In this paper, we introduce a definition of stability for the isospectral numerical methods. This definition involves a potential function associated to the isospectral flow. For the class EdGLRKs we propose a variable step-size strategy, based on this potential function, and an optimal constant time step h in the stability interval. The variable time step strategy will be compared with a known variable step-size strategy for RK methods applied to these dynamical systems. Numerical tests will be given and a comparison with the QR algorithm will be show
Variable step-size techniques in continuous Runge-Kutta methods for isospectral dynamical systems
No full textIn this paper we consider numerical methods for the dynamical system L′ = [B(L), L], L(0) = L0, (*) where L0 is a n × n symmetric matrix, [B(L), L] is the commutator of B(L) and L, and B(L) is a skew-symmetric matrix for each symmetric matrix L. The differential system is isospectral, i.e., L(t) preserves the eigenvalues of L0, for t ≥ 0. The matrix B(L) characterizes the flow, and for special B(·), the solution matrix L(t) tends, as t increases, to a diagonal matrix with the same eigenvalues of L0. In [11] a modification of the MGLRK methods, introduced in [2], has been proposed. These procedures are based on a numerical approximation of the Flaschka formulation of (*) by Runge-Kutta (RK) methods. Our numerical schemes (denoted by EdGLRKs) consist in solving the system (*) by a continuous explicit Runge-Kutta method (CERK) and then performing a single step of a Gauss-Legendre RK method, for the Flaschka formulation of (*), in order to convert the approximation of L(t) to an isospectral solution. The problems of choosing a constant time step or a variable time step strategy are both of great importance in the application of these methods. In this paper, we introduce a definition of stability for the isospectral numerical methods. This definition involves a potential function associated to the isospectral flow. For the class EdGLRKs we propose a variable step-size strategy, based on this potential function, and an optimal constant time step h in the stability interval. The variable time step strategy will be compared with a known variable step-size strategy for RK methods applied to these dynamical systems. Numerical tests will be given and a comparison with the QR algorithm will be shown
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