What Kind of Possibilities Do We Have?: Educators’ Complex Images of Latino Immigrant Students and Families

The Latino population in the United States is on the rise, but historically, Latino graduation rates have been low. Many educators lack sufficient intercultural preparation, and therefore, teachers may tend to blame student failure on cultural and familial deficiencies. In this study, we elicited educators’ perceptions of Latino students and the students’ families through 10 focus group interviews at 6 target schools (4 elementary schools, 1 middle school, and 1 high school). Findings include contradictory views of students’ and families’ attitudes towards education, and consistently negative views of students’ and families’ educational backgrounds. Latino families were seen as close, caring, and hardworking, but with the wrong priorities and in a state of crisis. Given these findings, we believe that there is a need for educators to question their assumptions through self- reflection, in order to overcome stereotyped images of Latino students. To that end, we recommend 3 overlapping tiers of professional learning with increasing depth of challenging experiences: (1) intercultural information, (2) intercultural inquiry, and (3) intercultural immersion

Monte Carlo Neutrino Oscillations

We demonstrate that the effects of matter upon neutrino propagation may be recast as the scattering of the initial neutrino wavefunction. Exchanging the differential, Schrodinger equation for an integral equation for the scattering matrix S permits a Monte Carlo method for the computation of S that removes many of the numerical difficulties associated with direct integration techniques

A tri-ionic anchor mechanism drives Ube2N-specific recruitment and K63-chain ubiquitination in TRIM ligases.

The cytosolic antibody receptor TRIM21 possesses unique ubiquitination activity that drives broad-spectrum anti-pathogen targeting and underpins the protein depletion technology Trim-Away. This activity is dependent on formation of self-anchored, K63-linked ubiquitin chains by the heterodimeric E2 enzyme Ube2N/Ube2V2. Here we reveal how TRIM21 facilitates ubiquitin transfer and differentiates this E2 from other closely related enzymes. A tri-ionic motif provides optimally distributed anchor points that allow TRIM21 to wrap an Ube2N~Ub complex around its RING domain, locking the closed conformation and promoting ubiquitin discharge. Mutation of these anchor points inhibits ubiquitination with Ube2N/Ube2V2, viral neutralization and immune signalling. We show that the same mechanism is employed by the anti-HIV restriction factor TRIM5 and identify spatially conserved ionic anchor points in other Ube2N-recruiting RING E3s. The tri-ionic motif is exclusively required for Ube2N but not Ube2D1 activity and provides a generic E2-specific catalysis mechanism for RING E3s

Dynamics of the Globular Cluster System Associated with M87 (NGC 4486). II. Analysis

We present a dynamical analysis of the globular cluster system associated with M87 (= NGC 4486), the cD galaxy near the dynamical center of the Virgo cluster. The analysis utilizes a new spectroscopic and photometric database which is described in a companion paper (Hanes et al. 2001). Using a sample of 278 globular clusters with measured radial velocities and metallicities, and new surface density profiles based on wide-field Washington photometry, we study the dynamics of the M87 globular cluster system both globally --- for the entire cluster sample --- and separately --- for the metal-rich and metal-poor globular cluster samples. This constitutes the largest sample of radial velocities for pure Population II tracers yet assembled for any galaxy. We discuss the implications of our findings for models for the formation of giant elliptical galaxies, globular cluster systems, and the Virgo cluster. (ABRIDGED)Comment: 28 pages, 19 postscript figures, 1 jpeg image. See http://www.physics.rutgers.edu/ast/ast-rap.html to download the manuscript with higher quality figures. Accepted for publication in the Astrophysical Journa

Discovery of a Probable CH Star in the Globular Cluster M14 and Implications for the Evolution of Binaries in Clusters

We report the discovery of a probable CH star in the core of the Galactic globular cluster M14, identified from an integrated-light spectrum of the cluster obtained with the MOS spectrograph on the CFHT. From a high- resolution echelle spectrum of the same star obtained with the Hydra fiber positioner and bench spectrograph on the WIYN telescope, we measure a radial velocity of $-53.0\pm1.2$ km s$^{-1}$. Although this velocity is inconsistent with published estimates of the systemic radial velocity of M14 (eg, ${\bar {v_r}} \approx -123$ km s$^{-1}$), we use high-precision Hydra velocities for 20 stars in the central 2.6 arcminutes of M14 to calculate improved values for the cluster mean velocity and one-dimensional velocity dispersion: $-59.5\pm1.9$ km s$^{-1}$ and $8.2\pm1.4$ km s$^{-1}$, respectively. Both the star's location near the tip of the red giant branch in the cluster color magnitude diagram and its radial velocity therefore argue for membership in M14. Since the intermediate-resolution MOS spectrum shows not only enhanced CH absorption but also strong Swan bands of C$_2$, M14 joins Omega Cen as the only globular clusters known to contain classical CH stars. Although evidence for its duplicity must await additional radial velocity measurements, the CH star in M14 is probably, like all field CH stars, a spectroscopic binary with a degenerate (white dwarf) secondary. The candidate and confirmed CH stars in M14 and Omega Cen, and in a number of Galactic dSph galaxies, may then owe their existence to the long timescales for the shrinking and coalescence of hard binaries in low-concentration environments.Comment: Accepted to the Astrophysical Journal Letters. 13 pages, AAS LaTeX and three postscript figures (numbers 2,3,4). Entire paper (including Figure 1) available at http://www.hia.nrc.ca/DAO/SCIENCE/science.htm

Extracellular Charge Adsorption Influences Intracellular Electrochemical Homeostasis in Amphibian Skeletal Muscle

The membrane potential measured by intracellular electrodes, Em, is the sum of the transmembrane potential difference (E1) between inner and outer cell membrane surfaces and a smaller potential difference (E2) between a volume containing fixed charges on or near the outer membrane surface and the bulk extracellular space. This study investigates the influence of E2 upon transmembrane ion fluxes, and hence cellular electrochemical homeostasis, using an integrative approach that combines computational and experimental methods. First, analytic equations were developed to calculate the influence of charges constrained within a three-dimensional glycocalyceal matrix enveloping the cell membrane outer surface upon local electrical potentials and ion concentrations. Electron microscopy confirmed predictions of these equations that extracellular charge adsorption influences glycocalyceal volume. Second, the novel analytic glycocalyx formulation was incorporated into the charge-difference cellular model of Fraser and Huang to simulate the influence of extracellular fixed charges upon intracellular ionic homeostasis. Experimental measurements of Em supported the resulting predictions that an increased magnitude of extracellular fixed charge increases net transmembrane ionic leak currents, resulting in either a compensatory increase in Na+/K+-ATPase activity, or, in cells with reduced Na+/K+-ATPase activity, a partial dissipation of transmembrane ionic gradients and depolarization of Em

Glyceryl trinitrate-induced vasodilation is inhibited by ultraviolet irradiation despite enhanced nitric oxide generation: evidence for formation of a nitric oxide conjugate

ABSTRACT Our objective was to determine whether a stabilized form of nitric oxide (NO) such as an S-nitrosothiol, rather than NO itself, is the vasoactive metabolite produced when glyceryl trinitrate (GTN) interacts with vascular smooth muscle. In a control study, NO formation was measured by a chemiluminescenceheadspace gas method during the incubation of a prototype S-nitrosothiol, namely, S-nitroso-N-acetylpenicillamine (SNAP), in Krebs' solution. NO formation from SNAP was increased when the incubation was carried out in the presence of UV light, indicating that homolytic photolysis of the S-nitrosothiol had occurred. When GTN was incubated with bovine pulmonary artery (BPA) in the absence of UV light, NO was not measurable until 5 min of incubation. By contrast, in the presence of UV light, NO was measurable as early as 0.5 min, and by 5 min, it was higher than that observed in the absence of UV light. BPA rings were relaxed with SNAP and GTN in the absence of UV light, and EC 50 values of 0.24 Ϯ 0.28 M and 10 Ϯ 6 nM, respectively, were observed. In the presence of UV light, the vasodilator response of BPA to SNAP and GTN was attenuated, and EC 50 values of 2.7 Ϯ 3.0 M and 49 Ϯ 23 nM, respectively, were observed. Our results are consistent with the idea that GTN biotransformation by vascular smooth muscle results in the production of a stabilized form of NO, possibly an S-nitrosothiol, and that degradation of this metabolite by UV light results in NO formation accompanied by decreased vasodilation

Oligodendroglial modulation of fast axonal transport in a mouse model of hereditary spastic paraplegia

Oligodendrocytes are critical for the development of the plasma membrane and cytoskeleton of the axon. In this paper, we show that fast axonal transport is also dependent on the oligodendrocyte. Using a mouse model of hereditary spastic paraplegia type 2 due to a null mutation of the myelin Plp gene, we find a progressive impairment in fast retrograde and anterograde transport. Increased levels of retrograde motor protein subunits are associated with accumulation of membranous organelles distal to nodal complexes. Using cell transplantation, we show categorically that the axonal phenotype is related to the presence of the overlying Plp null myelin. Our data demonstrate a novel role for oligodendrocytes in the local regulation of axonal function and have implications for the axonal loss associated with secondary progressive multiple sclerosis