Archivos musicales: la reflexión teórica y la vivencia

El archivo ha sido teorizado como lugar de exclusión, monumento al poder, depósito donde se construye una memoria externalizada, formador de identidad. Luego de pasar brevemente revista a algunas de estas formulaciones (Foucault, Derrida, Murguía, Didi-Huberman), el artículo procede a una somera descripción del carácter diverso de cuatro archivos musicales, y de las operaciones que en ellos he realizado como musicólogo. Aunque se resalta la importancia de la vivencia personal del archivo, se pone también de manifiesto la necesidad de reflexionar sobre las intersecciones entre la teoría previamente reseñada y las realidades prácticas de los archivos musicales. Son estas intersecciones esquivas, ya que el pensamiento sobre el tema toma como modelos archivos gubernamentales, policiales, legales, verdaderamente extraños al mundo caprichoso y muchas veces irracional de los archivos musicales

Subalternidad en músicas novohispanas: dos fragmentos

18 páginas.Capítulo incluido en el libro: De Nueva España a México: el universo musical mexicano entre centenarios (1517-1917). Javier Marín-López (ed. lit.). Sevilla, Universidad Internacional de Andalucía, 2020. Pags.: 591-607. Enlace: http://hdl.handle.net/10334/538

La contribución indígena a la música misional en Mojos (Bolivia)

In attempting to emphasize the value of indigenous agency in the musical practice of the Jesuit missons writers have posited the existance of "native composers" during the Jesuits' regime. Focusing on the misson area of Mojos, this article aims to demostrate that: 1) Indian compositional activity during the Jesuit period lacked importance and originality; 2) inmediately after the Jesuits' expulsion presumably some Indian composers emerge, writing in a characteristic style that differs from the European. This may have been a consequence of the new relationship established between musicians and the white society and the efficient spirit of some government officials; 3) during the Jesuit period, musical performance was the arena where Indians made an active and idiosyncratic contribution. En el intento de valorizar la acción indígena en la práctica musical de las reducciones, se ha hablado de "compositores indígenas" durante el régimen jesuítico. Centrándose en el área misional de Mojos, el presente estudio intenta establecer: 1) que la actividad compositiva indígena durante la administración jesuítica, si la hubo, careció de originalidad e importancia; 2) que inmediatamente después de la expulsión, como consecuencia de las nuevas relaciones establecidas por los músicos y del espíritu eficientista de algunos oficiales del gobierno, aparecen compositores presumiblemente indígenas que escriben en un estilo definido y diferente del europeo; 3) que durante la época jesuítica la práctica de la interpretación era el terreno donde los indígenasaportaban una contribución activa e idiosincrática. &nbsp

Tolerance without clonal expansion: Self-antigen-expressing B cells program self-reactive T cells for future deletion

B cells have been shown in various animal models to induce immunological tolerance leading to reduced immune responses and protection from autoimmunity. We show that interaction of B cells with naive T cells results in T cell triggering accompanied by the expression of negative costimulatory molecules such as PD-1, CTLA-4, B and T lymphocyte attenuator, and CD5. Following interaction with B cells, T cells were not induced to proliferate, in a process that was dependent on their expression of PD-1 and CTLA-4, but not CD5. In contrast, the T cells became sensitive to Ag-induced cell death. Our results demonstrate that B cells participate in the homeostasis of the immune system by ablation of conventional self-reactive T cells

Density fluctuations and the structure of a nonuniform hard sphere fluid

We derive an exact equation for density changes induced by a general external field that corrects the hydrostatic approximation where the local value of the field is adsorbed into a modified chemical potential. Using linear response theory to relate density changes self-consistently in different regions of space, we arrive at an integral equation for a hard sphere fluid that is exact in the limit of a slowly varying field or at low density and reduces to the accurate Percus-Yevick equation for a hard core field. This and related equations give accurate results for a wide variety of fields

Stage-specific control of oligodendrocyte survival and morphogenesis by TDP-43

Generation of oligodendrocytes in the adult brain enables both adaptive changes in neural circuits and regeneration of myelin sheaths destroyed by injury, disease, and normal aging. This transformation of oligodendrocyte precursor cells (OPCs) into myelinating oligodendrocytes requires processing of distinct mRNAs at different stages of cell maturation. Although mislocal- ization and aggregation of the RNA-binding protein, TDP-43, occur in both neurons and glia in neurodegenerative diseases, the consequences of TDP-43 loss within different stages of the oligo- dendrocyte lineage are not well understood. By performing stage-specific genetic inactivation of Tardbp in vivo, we show that oligodendrocyte lineage cells are differentially sensitive to loss of TDP- 43. While OPCs depend on TDP-43 for survival, with conditional deletion resulting in cascading cell loss followed by rapid regeneration to restore their density, oligodendrocytes become less sensitive to TDP-43 depletion as they mature. Deletion of TDP-43 early in the maturation process led to even- tual oligodendrocyte degeneration, seizures, and premature lethality, while oligodendrocytes that experienced late deletion survived and mice exhibited a normal lifespan. At both stages, TDP-43- deficient oligodendrocytes formed fewer and thinner myelin sheaths and extended new processes that inappropriately wrapped neuronal somata and blood vessels. Transcriptional analysis revealed that in the absence of TDP-43, key proteins involved in oligodendrocyte maturation and myelination were misspliced, leading to aberrant incorporation of cryptic exons. Inducible deletion of TDP-43 from oligodendrocytes in the adult central nervous system (CNS) induced the same progressive morphological changes and mice acquired profound hindlimb weakness, suggesting that loss of TDP-43 function in oligodendrocytes may contribute to neuronal dysfunction in neurodegenerative disease

Gel transitions in colloidal suspensions

The idealized mode coupling theory (MCT) is applied to colloidal systems interacting via short-range attractive interactions of Yukawa form. At low temperatures MCT predicts a slowing down of the local dynamics and ergodicity breaking transitions. The nonergodicity transitions share many features with the colloidal gel transition, and are proposed to be the source of gelation in colloidal systems. Previous calculations of the phase diagram are complemented with additional data for shorter ranges of the attractive interaction, showing that the path of the nonergodicity transition line is then unimpeded by the gas-liquid critical curve at low temperatures. Particular attention is given to the critical nonergodicity parameters, motivated by recent experimental measurements. An asymptotic model is developed, valid for dilute systems of spheres interacting via strong short-range attractions, and is shown to capture all aspects of the low temperature MCT nonergodicity transitions.Comment: 12 pages, LaTeX, 5 eps figures, uses ioplppt.sty, to appear in J. Phys.: Condens. Matte

Perturbation theory for very long-range potentials

Systems with very long-range interactions (that decay at large distances like $U(r)\sim r^{-l}$ with $l\le d$ where $d$ is the space dimensionality) are difficult to study by conventional statistical mechanics perturbation methods. Examples of these systems are gravitational and charged (non-electroneutral). In this work we propose two alternative methodologies to avoid these difficulties and capture some of the properties of the original potential. The first one consists in expressing the original potential in terms of a finite sum of hard-core Yukawa potentials. In the second one, the potential is rewritten as a damped potential, using a damping function with a parameter that controls the range of the interaction. These new potentials, which mimic the original one, can now be treated by conventional statistical mechanics methods.Comment: 25 pages, 11 figure

Theory and simulation of short-range models of globular protein solutions

We report theoretical and simulation studies of phase coexistence in model globular protein solutions, based on short-range, central, pair potential representations of the interaction among macro-particles. After reviewing our previous investigations of hard-core Yukawa and generalised Lennard-Jones potentials, we report more recent results obtained within a DLVO-like description of lysozyme solutions in water and added salt. We show that a one-parameter fit of this model based on Static Light Scattering and Self-Interaction Chromatography data in the dilute protein regime, yields demixing and crystallization curves in good agreement with experimental protein-rich/protein-poor and solubility envelopes. The dependence of cloud and solubility points temperature of the model on the ionic strength is also investigated. Our findings highlight the minimal assumptions on the properties of the microscopic interaction sufficient for a satisfactory reproduction of the phase diagram topology of globular protein solutions.Comment: 17 pages, 8 figures, Proc. of Conference "Structural Arrest Transitions in Colloidal Systems with Short-Range Attractions", Messina (ITALY) 17-20 December 200