8,055 research outputs found
Reseña de "El Estado y los indígenas en tiempos del PAN: neoindigenismo, legalidad e identidad" de Rosalva Aída Hernández, Sarela Paz y María Teresa Sierra (coords.)
The book gathers a series of texts where the situation of the indigenous peoples of Mexico is analyzed after the three first years of a government from the National Action Party. The long-expected “Political Transition of the Mexican Government” was a relevant event in the recent history of the country because of different factors: the change of the party in power, National Action Party (Partido Acción Nacional, PAN) managed to electorally defeat Institutional Revolutionary Party (Partido Revolucionario Institucional, PRI), which had governed the nation for more than seventy years; the advancement, in terms of the democratic consolidation of political processes, as the 2000 election showed important progress as for the strengthening of democratic institutions, which in previous elections lacked the faculties to grant the minimal democratic legitimacy; the setting into motion of a new way to exercise power by means of public and governmental policies, which at first were offered as plural and open to civil participation
Migration and Invasion of Brain Tumors
Recent advances in molecular biology have led to new insights in the development, growth and infiltrative behaviors of primary brain tumors (Demuth and Berens, 2004; Huse and Holland, 2010; Johnson et al., 2009; Kanu et al., 2009). These tumors are derived from various brain cell lineages and have been historically classified on the basis of morphological and, more recently, immunohistochemical features with less emphasis on their underlying molecular pathogenesis (Huse and Holland, 2010). The detailed molecular characterization of brain tumors has laid the groundwork for augmentation of standard treatment with patient-specific designed targeted therapies (Johnson et al., 2009; Kanu et al., 2009). Nevertheless, these tumors are extremely aggressive in their infiltration of brain tissue (Altman et al., 2007; Hensel et al., 1998; Yamahara et al., 2010), as well as in their metastasis outside of brain (Algra et al., 1992). Further, it now appears that the physiological conditions of the normal brain itself constitute a biological environment conducive to the uncontrolled dissemination of primary tumors (Bellail et al., 2004; Sontheimer, 2004). This review surveys the latest research on the invasive behavior of two major types of primary brain tumors: gliomas and medulloblastomas - the most common tumors diagnosed within adult and pediatric brain, respectively (Rickert and Paulus, 2001). The material has been divided into five sections: i) Characteristics of malignant brain tumors; ii) Mechanisms of tumor cell migration; iii) Models for the study of brain tumor invasion in vivo and ex vivo; iv) Models for the study of brain tumor invasion in vitro; and v) Future prospects of anti-invasive brain tumor therapy
A Microfluidic Device to Establish Concentration Gradients Using Reagent Density Differences
Microfabrication has become widely utilized to generate controlled microenvironments that establish chemical concentration gradients for a variety of engineering and life science applications. To establish microfluidic flow, the majority of existing devices rely upon additional facilities, equipment, and excessive reagent supplies, which together limit device portability as well as constrain device usage to individuals trained in technological disciplines. The current work presents our laboratory-developed bridged microLane system, which is a stand-alone device that runs via conventional pipette loading and can operate for several days without need of external machinery or additional reagent volumes. The bridged microLane is a two-layer polydimethylsiloxane microfluidic device that is able to establish controlled chemical concentration gradients over time by relying solely upon differences in reagent densities. Fluorescently labeled Dextran was used to validate the design and operation of the bridged microLane by evaluating experimentally measured transport properties within the microsystem in conjunction with numerical simulations and established mathematical transport models. Results demonstrate how the bridged microLane system was used to generate spatial concentration gradients that resulted in experimentally measured diffusivity
Conflicto por el agua en el Sistema de Riego Tepetitlán después de la trasferencia
El objetivo del artículo es identificar y explicar el conflicto surgido en el Sistema de Riego Tepetitlán, Estado de México, a partir de la trasferencia de los distritos de riego a los usuarios, en 1993, consistente en la entrega de obras de infraestructura. El Sistema de Riego Tepetitlán fue trasferido según la modalidad de unidad de riego, poco conocida en los estudios en México. Aquí se analiza este sistema bajo la lente del conflicto; se identifica y examina los momentos coyunturales que lo propician en las organizaciones de regantes, y se explica la situación actual de administración, operación y manejo del regadío
TGFβ signaling is associated with changes in inflammatory gene expression and perineuronal net degradation around inhibitory neurons following various neurological insults
Brain damage due to stroke or traumatic brain injury (TBI), both leading
causes of serious long-term disability, often leads to the development of
epilepsy. Patients who develop post-injury epilepsy tend to have poor
functional outcomes. Emerging evidence highlights a potential role for blood-
brain barrier (BBB) dysfunction in the development of post-injury epilepsy.
However, common mechanisms underlying the pathological hyperexcitability are
largely unknown. Here, we show that comparative transcriptome analyses predict
remodeling of extracellular matrix (ECM) as a common response to different
types of injuries. ECM-related transcriptional changes were induced by the
serum protein albumin via TGFβ signaling in primary astrocytes. In accordance
with transcriptional responses, we found persistent degradation of protective
ECM structures called perineuronal nets (PNNs) around fast-spiking inhibitory
interneurons, in a rat model of TBI as well as in brains of human epileptic
patients. Exposure of a naïve brain to albumin was sufficient to induce the
transcriptional and translational upregulation of molecules related to ECM
remodeling and the persistent breakdown of PNNs around fast-spiking inhibitory
interneurons, which was contingent on TGFβ signaling activation. Our findings
provide insights on how albumin extravasation that occurs upon BBB dysfunction
in various brain injuries can predispose neural circuitry to the development
of chronic inhibition deficits
QM7-X: A comprehensive dataset of quantum-mechanical properties spanning the chemical space of small organic molecules
We introduce QM7-X, a comprehensive dataset of 42 physicochemical properties
for 4.2 M equilibrium and non-equilibrium structures of small organic
molecules with up to seven non-hydrogen (C, N, O, S, Cl) atoms. To span this
fundamentally important region of chemical compound space (CCS), QM7-X includes
an exhaustive sampling of (meta-)stable equilibrium structures - comprised of
constitutional/structural isomers and stereoisomers, e.g., enantiomers and
diastereomers (including cis-/trans- and conformational isomers) - as well as
100 non-equilibrium structural variations thereof to reach a total of
4.2 M molecular structures. Computed at the tightly converged
quantum-mechanical PBE0+MBD level of theory, QM7-X contains global (molecular)
and local (atom-in-a-molecule) properties ranging from ground state quantities
(such as atomization energies and dipole moments) to response quantities (such
as polarizability tensors and dispersion coefficients). By providing a
systematic, extensive, and tightly-converged dataset of quantum-mechanically
computed physicochemical properties, we expect that QM7-X will play a critical
role in the development of next-generation machine-learning based models for
exploring greater swaths of CCS and performing in silico design of molecules
with targeted properties
Multifunctional P-Doped TiO2 Films: A New Approach to Self-Cleaning, Transparent Conducting Oxide Materials
Multifunctional P-doped TiO2 thin films were synthesized by atmospheric pressure chemical vapor deposition (APCVD). This is the first example of P-doped TiO2 films with both P5+ and P3– states, with the relative proportion being determined by synthesis conditions. This technique to control the oxidation state of the impurities presents a new approach to achieve films with both self-cleaning and TCO properties. The origin of electrical conductivity in these materials was correlated to the incorporation of P5+ species, as suggested by Hall Effect probe measurements. The photocatalytic performance of the films was investigated using the model organic pollutant, stearic acid, with films containing predominately P3– states found to be vastly inferior photocatalysts compared to undoped TiO2 films. Transient absorption spectroscopy studies also showed that charge carrier concentrations increased by several orders of magnitude in films containing P5+ species only, whereas photogenerated carrier lifetimes—and thus photocatalytic activity—were severely reduced upon incorporation of P3– species. The results presented here provide important insights on the influence of dopant nature and location within a semiconductor structure. These new P-doped TiO2 films are a breakthrough in the development of multifunctional advanced materials with tuned properties for a wide range of applications
Higher-order hydrodynamics: Extended Fick's Law, evolution equation, and Bobylev's instability
A higher-order hydrodynamics for material motion in fluids, under arbitrary nonequilibrium conditions, is constructed. We obtain what is a generalized-to that conditions-Fick-type Law. It includes a representation of Burnett-type contributions of all order, in the form of a continuous-fraction expansion. Also, the equation includes generalized thermodynamic forces. which are characterized and discussed. All kinetic coefficients are given as correlations of microscopic mechanical quantities averaged over the nonequilibrium ensemble, and then are time- and space-dependent as a consequence of accounting for the dissipative processes that are unfolding in the medium. An extended evolution equation for the density of particles is derived, and the conditions when it goes over restricted forms of the type of the telegraphist equation and Fick's diffusion equation are presented. (C) 2002 American Institute of Physics.11641571158
Evolution of dissipative processes via a statistical thermodynamic approach. II. Thermodynamic properties of a fluid of bosons
On the basis of the generalized Mori-Heisenberg-Langevin equations presented in the preceding paper, we derive and analyze the informational-statistical thermodynamic properties of a fluid of bosons away from equilibrium. We derive the informational entropy and its production, proceeding to an analysis of the several contributions to these state functions arising out of the evolution of dissipative processes in the system. (C) 1998 American Institute of Physics.108187580758
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