No Supermassive Black Hole in M33?

We analyze optical long-slit spectroscopy of the nucleus of M33 obtained from the Space Telescope Imaging Spectrograph aboard the Hubble Space Telescope. Rather than the steep rise expected within the radius of influence of a supermassive black hole, the velocity dispersion drops significantly within the inner parsec. Dynamical modelling yields an estimated upper limit of 3000 solar masses for the mass of a central compact object. This upper limit is however consistent within the uncertainties with the mass predicted by the M-sigma relation, which is between 2000 and 20,000 solar masses. We therefore can not conclude that the presence of a massive black hole in the nucleus of M33 would require a different formation mechanism from that of the black holes detected in galaxies with more luminous bulges.Comment: 10 pages, 4 postscript figure

Planning for Enrichment and Equity in Dual Language Education: A Study of Eight Program Master Plans

This qualitative study analyzed eight dual language master plans developed by school districts on the West Coast of the United States. Each of the plans represented one or more dual language programs within each school district. The purpose of the study was to determine how school districts express their priorities for dual language programming. Master plans were analyzed for their structure, rationales, and their intended impact on students and families. Through numerous coding passes, several themes revealed themselves related to proposed benefits to students in language, academics, and social-emotional growth. The findings of this study indicated an informal community of practice among the groups who wrote the plans, and conceptions of family involvement that positioned families as receivers, rather than actors in the education of their children. This analysis illuminated areas where equity in emergent bilinguals’ access to authentic language and parent involvement could be improved. Implications for further research point to the need for ethnographic study of programs as compared to their plans, and a deeper examination of the ways the dual language community of practice functions. Implications for practice include the need to expand the implied canon of dual language research informing dual language master planning, and the importance of revisiting translanguaging for both pedagogical and equity reasons. Finally, future dual language master planning ought to expand on particular ways to support new teachers in this complex work through locally-relevant professional training and leadership roles

The Low End of the Supermassive Black Hole Mass Function: Constraining the Mass of a Nuclear Black Hole in NGC 205 via Stellar Kinematics

Hubble Space Telescope (HST) images and spectra of the nucleated dwarf elliptical galaxy NGC 205 are combined with 3-integral axisymmetric dynamical models to constrain the mass (M_BH) of a putative nuclear black hole. This is only the second attempt, after M33, to use resolved stellar kinematics to search for a nuclear black hole with mass below 10^6 solar masses. We are unable to identify a best-fit value of M_BH in NGC 205; however, the data impose a upper limit of 2.2x10^4 M_sun (1sigma confidence) and and upper limit of 3.8x10^4 M_sun (3sigma confidence). This upper limit is consistent with the extrapolation of the M_BH-sigma relation to the M_BH < 10^6 M_sunregime. If we assume that NGC 205 and M33 both contain nuclear black holes, the upper limits on M_BH in the two galaxies imply a slope of ~5.5 or greater for the M_BH-sigma relation. We use our 3-integral models to evaluate the relaxation time (T_r) and stellar collision time (T_coll) in NGC 205; T_r~10^8 yr or less in the nucleus and T_coll~10^11 yr. The low value of T_r is consistent with core collapse having already occurred, but we are unable to draw conclusions from nuclear morphology about the presence or absence of a massive black hole.Comment: Latex emulateapj, 15 pages, 16 figures, Version accepted for Publication in ApJ, 20 July 2005, v628. Minor changes to discussion

Are Universities Providing Non-STEM Students the Mathematics Preparation Required by Their Programs?: A Case Study of a Quantitative Literacy Pathway and Vertical Alignment from Remediation to Degree Completion

Informed by Gagne\u27s belief in the necessity of prerequisite knowledge for new learning, and Bruner\u27s Spiral Curriculum Theory, the objective of this case study was to explore the postsecondary pathway from remedial mathematics, through one gateway mathematics course, and into the quantitative literacy requirements of various non-STEM programs of study. Particular attention was directed towards analyses of the vertical alignment of course content between: (1) the two consecutive remedial mathematics courses (Beginning Algebra and Intermediate Algebra), (2) the two remedial courses and the gateway course (Fundamentals of College Mathematics), and (3) the gateway course and the quantitative literacy needs of the higher-level coursework in the programs of study. A thorough examination of artifacts and feedback from participants were employed to determine the contents of and prerequisite skills for the mathematics courses. Survey results and extant literature were analyzed to determine the quantitative literacy requirements for later coursework within non-STEM programs of study. Comparison matrices were then utilized to explore the extent of vertical alignment by analyzing overlaps in content from course to course, and by matching prerequisites to course contents throughout the pathway. Evidence of gaps in vertical alignment was discovered, leading to recommendations for changes in course content necessary to fill those gaps

Texas Citrus Market Promotion.

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Texas Citrus Marketing Regulations.

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River Erosion In Block-Controlled Landscapes

Rivers are the backbone of the landscape. The efficiency of fluvial bedrock erosion and sediment transport sets the longevity of high topography, and represents the boundary conditions experienced by the rest of the landscape. The rate at which rivers respond to tectonic, climatic, and anthropogenic perturbations governs the extent to which those events are recorded in remnant topography and the stratigraphic record. The past two decades have seen substantial progress on quantifying and understanding river incision processes and what controls them, including the effects of realistic hydrology, sediment flux, and rock strength. In addition, some progress has been made on understanding the effects of sediment grain size on river erosion. However, much work remains to be done on how sediment dynamics govern fluvial incision. In particular, despite a long tradition of speculation based on qualitative field observations, there has been very little work on how rivers react to the delivery of very large (&gt; 1 m) sediment grains, and how large grains modulate the long-term dynamics of river and landscape evolution. In this thesis I present five studies with the goal of understanding how sediment size and sediment flux interact to influence river incision and long-term landscape change. In Chapter 1, I briefly lay out previous work exploring links among sediment flux, sediment size, river erosion and landscape evolution outcomes. Chapter 2 lays out a conceptual and numerical model for how large sediment grains, "blocks" of rock delivered from hillslopes to channels, alter river channel form and change how baselevel perturbations are transmitted along channel profiles. The model is compared with observations from Boulder Creek, Colorado. I extend this work in Chapter 3 to explore how the distribution of river discharge interacts with the presence of hillslope-derived blocks to set steady-state scaling between erosion rate and river channel steepness. I develop a simplified framework to account for the role of blocks and compare its predictions against measured erosion rate-channel steepness relationships. In Chapter 4, I couple the numerical model for block-influenced river erosion with a previously published model for block-influenced hillslopes, and show that block transport feedbacks between channels and hillslopes can explain observations of river canyon morphology in layered rock landscapes. I further show that these feedbacks play an important role in modulating baselevel perturbations as they travel through block-influenced landscapes. I use a well-constrained field site in Chapter 5 to evaluate whether lithologically controlled channel steepening could be caused by boulder delivery to channels occurring in one lithology but not in others, and suggest that boulder delivery may be a mechanism by which lithology leaves its mark on landscapes. In Chapter 6 I develop a new numerical model to simulate erosion in bedrock-alluvial rivers, which until recently have been oversimplified in models of landscape evolution. I conclude by pointing out future research directions related to sediment size, river incision, and topographic change at Earth's surface.</p

Supermassive Black Holes in Active Galactic Nuclei. I. The Consistency of Black Hole Masses in Quiescent and Active Galaxies

We report the first results of a program to measure accurate stellar velocity dispersions in the bulges of the host galaxies of active galactic nuclei (AGNs) for which accurate black hole (BH) masses have been determined via reverberation mapping. We find good agreement between BH masses obtained from reverberation mapping, and from the M(BH) - sigma relation as defined by quiescent galaxies, indicating a common relationship between active and quiescent black holes and their large-scale environments.Comment: Submitted to ApJ