1,171 research outputs found
Ephrin regulation of palate development
Studies of palate development are motivated by the all too common incidence of cleft palate, a birth defect that imposes a tremendous health burden and can leave lasting disfigurement. Although, mechanistic studies of palate growth and fusion have focused on growth factors such as Transforming Growth Factor Ă-3 (TgfĂ3), recent studies have revealed that the ephrin family of membrane bound ligands and their receptors, the Ephs, play central roles in palatal morphogenesis, growth, and fusion. In this mini-review, we will discuss the recent findings by our group and others on the functions of ephrins in palatal development
The spectrum of BPS branes on a noncompact Calabi-Yau
We begin the study of the spectrum of BPS branes and its variation on lines
of marginal stability on O_P^2(-3), a Calabi-Yau ALE space asymptotic to
C^3/Z_3. We show how to get the complete spectrum near the large volume limit
and near the orbifold point, and find a striking similarity between the
descriptions of holomorphic bundles and BPS branes in these two limits. We use
these results to develop a general picture of the spectrum. We also suggest a
generalization of some of the ideas to the quintic Calabi-Yau.Comment: harvmac, 45 pp. (v2: added references
Yours ever (well, maybe): Studies and signposts in letter writing
Electronic mail and other digital communications technologies seemingly threaten to end the era of handwritten and typed letters, now affectionately seen as part of snail mail. In this essay, I analyze a group of popular and scholarly studies about letter writing-including examples of pundits critiquing the use of e-mail, etiquette manuals advising why the handwritten letter still possesses value, historians and literary scholars studying the role of letters in the past and what it tells us about our present attitudes about digital communications technologies, and futurists predicting how we will function as personal archivists maintaining every document including e-mail. These are useful guideposts for archivists, providing both a sense of the present and the past in the role, value and nature of letters and their successors. They also provide insights into how such documents should be studied, expanding our gaze beyond the particular letters, to the tools used to create them and the traditions dictating their form and function. We also can discern a role for archivists, both for contributing to the literature about documents and in using these studies and commentaries, suggesting not a new disciplinary realm but opportunities for new interdisciplinary work. Examining a documentary form makes us more sensitive to both the innovations and traditions as it shifts from the analog to the digital; we can learn not to be caught up in hysteria or nostalgia about one form over another and archivists can learn about what they might expect in their labors to document society and its institutions. At one time, paper was part of an innovative technology, with roles very similar to the Internet and e-mail today. It may be that the shifts are far less revolutionary than is often assumed. Reading such works also suggests, finally, that archivists ought to rethink how they view their own knowledge and how it is constructed and used. © 2010 Springer Science+Business Media B.V
Multi-component measurements of the Jefferson Lab energy recovery linac electron beam using optical transition and diffraction radiation
High brightness electron accelerators, such as energy recovery linacs (ERL),
often have complex particle distributions that can create difficulties in beam
transport as well as matching to devices such as wigglers used to generate
radiation from the beam. Optical transition radiation (OTR), OTR interferometry
(OTRI) and optical diffraction-transition radiation interferometry (ODTRI) have
proven to be effective tools for diagnosing both the spatial and angular
distributions of charged particle beams. OTRI and ODTRI have been used to
measure rms divergences and optical transverse phase space mapping has been
demonstrated using OTRI. In this work we present the results of diagnostic
experiments using OTR and ODR conducted at the Jefferson Laboratory 115 MeV ERL
which show the presence of two separate components within the spatial and
angular distributions of the beam. By assuming a correlation between the
spatial and angular features we estimate an rms emittance value for each of the
two components.Comment: 25 pages, 10 figures; accepted for publication in PRSTAB; minor
formatting errors correcte
Beyond the Red, Purple, and Blue: Election Law Issues in 2012
The Symposium Welcome was given by Clint A. Nichols, the Allen Chair Editor for the University of Richmond Law Review, and Wendy C. Perdue, Dean & Professor of Law at the University of Richmond School of Law.
The âGet out the vote?â session was presented by Keesha M. Gaskins, Senior Counsel with the Brennan Center for Justice at New York University; Steven F. Huefner, Professor of Law and Director of Clinical Programs at The Ohio State University Moritz College of Law; Joshua N. Lief, Senior Assistant Attorney General for the Commonwealth of Virginia; and Michael J. Pitts, Professor of Law and Deanâs Fellow at Indiana Universityâs Robert H. McKinney School of Law.
The âThird Parties to the Processâ session was presented by Jocelyn F. Benson, Associate Professor of Law at Wayne State University Law School; Joshua A. Douglas, Assistant Professor of Law at the University of Kentucky College of Law; and Rebecca Green, Professor of the Practice of Law and Co-Director of the Election Law Program at the William & Mary Law School.
The âDrawing the Linesâ session was presented by Keesha M. Gaskins, Senior Counsel with the Brennan Center for Justice at New York University; Dale Ho, Assistant Counsel with the NAACP Legal Defense and Educational Fund; Dr. Michael P. McDonald, Associate Professor of Government and Politics at George Mason University; Donald Palmer, Secretary of the Virginia State Board of Elections; and Rob Richie, Executive Director of FairVote
On the Job
<p>DPSCs were exposed to various MG132 or p65 siRNA concentrations (A and B, respectively) and cytokines in the presence of MG132 or p65 siRNA (C and D, respectively) for 7 days. Col(I)-α1 mRNA was assayed using qRT-PCR. Data are presented as the mean ± S. E. M. of triplicate measures from triplicate experiments. Symbols: Asterisks (*) indicate statistical comparison with control result; plus signs (+) indicate statistical comparison with IL-1ÎČ (0.5 ng/ml) and TNFα (1.0 ng/ml) treatment (low cytokine dose); triangle (Î) indicates statistical comparison with IL-1ÎČ (10.0 ng/ml) and TNFα (20.0 ng/ml) treatment (high cytokine dose). Statistical comparison was made using ANOVA testing with Dunnettâs posthoc analysis. Statistical significance was represented by *, +, or Î for <i>p</i> < 0.05; **, ++, or ÎÎ for p < 0.01; ***, +++, or ÎÎÎ for p < 0.001.</p
Seeing the way: visual sociology and the distance runner's perspective
Employing visual and autoethnographic data from a twoâyear research project on distance runners, this article seeks to examine the activity of seeing in relation to the activity of distance running. One of its methodological aims is to develop the linkage between visual and autoethnographic data in combining an observationâbased narrative and sociological analysis with photographs. This combination aims to convey to the reader not only some of the specific subcultural knowledge and particular ways of seeing, but also something of the runner's embodied feelings and experience of momentum en route. Via the combination of narrative and photographs we seek a more effective way of communicating just how distance runners see and experience their training terrain. The importance of subjecting mundane everyday practices to detailed sociological analysis has been highlighted by many sociologists, including those of an ethnomethodological perspective. Indeed, without the competence of social actors in accomplishing these mundane, routine understandings and practices, it is argued, there would in fact be no social order
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High-resolution quantitative imaging of mammalian and bacterial cells using stable isotope mass spectrometry
Background: Secondary-ion mass spectrometry (SIMS) is an important tool for investigating isotopic composition in the chemical and materials sciences, but its use in biology has been limited by technical considerations. Multi-isotope imaging mass spectrometry (MIMS), which combines a new generation of SIMS instrument with sophisticated ion optics, labeling with stable isotopes, and quantitative image-analysis software, was developed to study biological materials. Results: The new instrument allows the production of mass images of high lateral resolution (down to 33 nm), as well as the counting or imaging of several isotopes simultaneously. As MIMS can distinguish between ions of very similar mass, such as ^{12}C^{15}N^{-} and ^{13}C^{14}N^{-}, it enables the precise and reproducible measurement of isotope ratios, and thus of the levels of enrichment in specific isotopic labels, within volumes of less than a cubic micrometer. The sensitivity of MIMS is at least 1,000 times that of ^{14}C autoradiography. The depth resolution can be smaller than 1 nm because only a few atomic layers are needed to create an atomic mass image. We illustrate the use of MIMS to image unlabeled mammalian cultured cells and tissue sections; to analyze fatty-acid transport in adipocyte lipid droplets using ^{13}C-oleic acid; to examine nitrogen fixation in bacteria using ^{15}N gaseous nitrogen; to measure levels of protein renewal in the cochlea and in post-ischemic kidney cells using ^{15}N-leucine; to study DNA and RNA co-distribution and uridine incorporation in the nucleolus using ^{15}N-uridine and ^{81}Br of bromodeoxyuridine or ^{14}C-thymidine; to reveal domains in cultured endothelial cells using the native isotopes ^{12}C, ^{16}O, ^{14}N and ^{31}P; and to track a few ^{15}N-labeled donor spleen cells in the lymph nodes of the host mouse. Conclusion: MIMS makes it possible for the first time to both image and quantify molecules labeled with stable or radioactive isotopes within subcellular compartments
Mass-to-light ratio gradients in early-type galaxy haloes
Since the near future should see a rapidly expanding set of probes of the
halo masses of individual early-type galaxies, we introduce a convenient
parameter for characterising the halo masses from both observational and
theoretical results: \dML, the logarithmic radial gradient of the mass-to-light
ratio. Using halo density profiles from LCDM simulations, we derive predictions
for this gradient for various galaxy luminosities and star formation
efficiencies . As a pilot study, we assemble the available \dML\
data from kinematics in early-type galaxies - representing the first unbiassed
study of halo masses in a wide range of early-type galaxy luminosities - and
find a correlation between luminosity and \dML, such that the brightest
galaxies appear the most dark-matter dominated. We find that the gradients in
most of the brightest galaxies may fit in well with the LCDM predictions, but
that there is also a population of fainter galaxies whose gradients are so low
as to imply an unreasonably high star formation efficiency .
This difficulty is eased if dark haloes are not assumed to have the standard
LCDM profiles, but lower central concentrations.Comment: 17 pages, 13 figures. Accepted for publication on MNRA
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