Search results for "Native"

Protein Tyrosine Nitration Induced by Heme/Hydrogen Peroxide: Inhibitory Effect of Hydroxycinnamoyl Conjugates

2006

The present study was designed to optimize the experimental conditions that govern the heme-catalyzed nitration of protein tyrosine residues by nitrite, and, within this framework, to study the effects of 3,5-dicaffeoylquinic acid and its methyl ester, both of which have been previously reported to be antioxidants and inhibitors of leukocyte functions. Although the presence of hydrogen peroxide is essential in cell-free systems, an excess of this compound was found to be detrimental, so much so that an increase in hemin concentration actually resulted in an inverse effect on the reaction, depending on the levels of fixed hydrogen peroxide. Unlike previous reports on nitrite-induced albumin …

Digestive vacuole of Plasmodium falciparum released during erythrocyte rupture dually activates complement and coagulation.

2012

Abstract Severe Plasmodium falciparum malaria evolves through the interplay among capillary sequestration of parasitized erythrocytes, deregulated inflammatory responses, and hemostasis dysfunction. After rupture, each parasitized erythrocyte releases not only infective merozoites, but also the digestive vacuole (DV), a membrane-bounded organelle containing the malaria pigment hemozoin. In the present study, we report that the intact organelle, but not isolated hemozoin, dually activates the alternative complement and the intrinsic clotting pathway. Procoagulant activity is destroyed by phospholipase C treatment, indicating a critical role of phospholipid head groups exposed at the DV surfa…

Massless positivity in graviton exchange

2021

We formulate Positivity Bounds for scattering amplitudes including exchange of massless particles. We generalize the standard construction through dispersion relations to include the presence of a branch cut along the real axis in the complex plane for the Maldestam variable $s$. In general, validity of these bounds require the cancellation of divergences in the forward limit of the amplitude, proportional to $t^{-1}$ and $\log(t)$. We show that this is possible in the case of gravitons if one assumes a Regge behavior of the amplitude at high energies below the Planck scale, as previously suggested in the literature, and that the concrete UV behaviour of the amplitude is uniquely determined…

Infrared lessons for ultraviolet gravity: the case of massive gravity and Born-Infeld

2014

We generalize the ultraviolet sector of gravitation via a Born-Infeld action using lessons from massive gravity. The theory contains all of the elementary symmetric polynomials and is treated in the Palatini formalism. We show how the connection can be solved algebraically to be the Levi-Civita connection of an effective metric. The non-linearity of the algebraic equations yields several branches, one of which always reduces to General Relativity at low curvatures. We explore in detail a {\it minimal} version of the theory, for which we study solutions in the presence of a perfect fluid with special attention to the cosmological evolution. In vacuum we recover Ricci-flat solutions, but also…

On gravitational waves in Born-Infeld inspired non-singular cosmologies

2017

We study the evolution of gravitational waves for non-singular cosmological solutions within the framework of Born-Infeld inspired gravity theories, with special emphasis on the Eddington-inspired Born-Infeld theory. We review the existence of two types of non-singular cosmologies, namely bouncing and asymptotically Minkowski solutions, from a perspective that makes their features more apparent. We study in detail the propagation of gravitational waves near these non-singular solutions and carefully discuss the origin and severity of the instabilities and strong coupling problems that appear. We also investigate the role of the adiabatic sound speed of the matter sector in the regularisatio…

Correlation patterns from massive phonons in 1+1 dimensional acoustic black holes: A toy model

2018

Transverse excitations in analogue black holes induce a mass like term in the longitudinal mode equation. With a simple toy model we show that correlation functions display a rather rich structure characterized by groups of parallel peaks. For the most part the structure is completely different from that found in the massless case.

El acceso de los hijos de inmigrantes a la Educación Superior en España ¿una cuestión de origen étnico o de origen social?

2021

El presente trabajo se enmarca dentro de los estudios sobre la Dimensión Social de la Educación Superior (DOES). En él se estudia el peso que la posición socioeconómica tiene en el acceso a la Educación Superior de las segundas generaciones en España. Para ello analizamos la probabilidad de que los estudiantes con antecedentes migratorios y diferentes orígenes socioeconómicos realizaran estudios terciarios durante la segunda década del siglo XXI en contraste con la población autóctona de nuevo ingreso. En nuestros resultados encontramos diferencias significativas en el acceso a la universidad entre los jóvenes con edades comprendidas entre los 18 y 21 años, pertenecientes a las segundas gen…

Rosalyn R. LaPier and David R. M. Beck's <i>City Indian: Native American Activism in Chicago, 1893-1934</i>

2015

Gertrude Bonnin on Sexual Morality

2021

This paper examines attitudes to sexual morality held by the Yankton Dakota author and activist Gertrude Bonnin (1876–1938), better known by her penname Zitkála-Šá (Red Bird in Lakota). Bonnin’s concerns encompass several themes: the victimization of Indian women, disintegration of Native courtship rituals, sexual threats posed by peyote use, and the predatory nature of Euro-American men. This critique as a whole — in which a ‘white invasion,’ in her words, leads to a corruption of Native sexuality — sometimes produces inconsistencies, particularly regarding Bonnin’s statements on the alleged sexual perils of peyote. Her investigations into the Oklahoma guardianship scandals of the 1920s, h…

Comment: What is Alternative Technology? A Reply to Professor Stanley Carpenter

1983

Modern man is dissatisfied with the technology we have and would replace it with another. Three very different reasons are given for this. I will divide my treatment of them under three headings, listing the reason in each case together with a reply.