Genetic tracing of the epithelial lineage during mammalian kidney repair

Developing new therapeutic approaches to treat acute kidney injury requires a detailed understanding of endogenous cellular repair. Genetic fate mapping defines cellular hierarchies in vivo and we used this technique to assess a possible contribution of non-epithelial stem cells to renal repair after ischemic injury. Mice with efficient labeling of renal epithelial cells, but not non-epithelial interstitial cells, were subjected to a single cycle or sequential cycles of kidney injury and repair. No dilution of the epithelial cell fate marker was observed despite robust epithelial cell proliferation. Thus, non-tubular cells do not have the ability to migrate across the basement membrane and differentiate into epithelial cells in this model. Instead, surviving tubular epithelial cells are responsible for repair of the damaged nephron. Future studies will need to distinguish between uniform dedifferentiation and proliferation of all epithelial cells after injury versus selective expansion of an intratubular epithelial stem cell

Center and representations of infinitesimal Hecke algebras of sl_2

In this paper, we compute the center of the infinitesimal Hecke algebras Hz associated to sl_2 ; then using nontriviality of the center, we study representations of these algebras in the framework of the BGG category O. We also discuss central elements in infinitesimal Hecke algebras over gl(n) and sp(2n) for all n. We end by proving an analogue of the theorem of Duflo for Hz.Comment: Final form, to appear in "Communications in Algebra"; 35 pages, laTe

A Tale of Two Impostors: SN2002kg and SN1954J in NGC 2403

We describe new results on two supernova impostors in NGC 2403, SN 1954J(V12) and SN 2002kg(V37). For the famous object SN 1954J we combine four critical observations: its current SED, its Halpha emission line profile, the Ca II triplet in absorption in its red spectrum, and the brightness compared to its pre-event state. Together these strongly suggest that the survivor is now a hot supergiant with T ~ 20000 K, a dense wind, substantial circumstellar extinction, and a G-type supergiant companion. The hot star progenitor of V12's giant eruption was likely in the post-red supergiant stage and had already shed a lot of mass. V37 is a classical LBV/S Dor variable. Our photometry and spectra observed during and after its eruption show that its outburst was an apparent transit on the HR Diagram due to enhanced mass loss and the formation of a cooler, dense wind. V37 is an evolved hot supergiant at ~10^6 Lsun with a probable initial mass of 60 -80 Msun.Comment: To appear in the Astrophysical Journa

GNSS Signal Authentication via Power and Distortion Monitoring

We propose a simple low-cost technique that enables civil Global Positioning System (GPS) receivers and other civil global navigation satellite system (GNSS) receivers to reliably detect carry-off spoofing and jamming. The technique, which we call the Power-Distortion detector, classifies received signals as interference-free, multipath-afflicted, spoofed, or jammed according to observations of received power and correlatio n function distortion. It does not depend on external hardware or a network connection and can be readily implemented on many receivers via a firmware update. Crucially, the detector can with high probability distinguish low-power spoofing from ordinary multipath. In testing against over 25 high-quality empirical data sets yielding over 900,000 separate detection tests, the detector correctly alarms on all malicious spoofing or jamming attack s while maintaining a <0.5% single-channel false alarm rate.Aerospace Engineering and Engineering Mechanic

Small-scale convection beneath the transverse ranges, California: Implications for interpretation of gravity anomalies

Tomographic inversion of upper mantle P wave velocity heterogeneities beneath southern California shows two prominent features: an east-west trending curtain of high velocity material (up to 3% fast) in the upper 250 km beneath the Transverse Ranges and a region of low velocity material (up to 4% slow) in the 100 km beneath the Salton Trough. These seismic velocity anomalies were interpreted as due to small scale convection in the mantle. Using this hypothesis and assuming that temperature and density anomalies are linearly related to seismic velocity anomalies through standard coefficients of proportionality, leads to inferred variations of approx. + or - 300 C and approx. + or - 0.03 g/cc

Unveiling Sources of Heating in the Vicinity of the Orion BN/KL Hot Core as Traced by Highly Excited Inversion Transitions of Ammonia

Using the Expanded Very Large Array, we have mapped the vicinity of the Orion BN/KL Hot Core with sub-arcsecond angular resolution in seven metastable inversion transitions of ammonia: (J,K)=(6,6) to (12,12). This emission comes from levels up to 1500 K above the ground state, enabling identification of source(s) responsible for heating the region. We used this multi-transition dataset to produce images of the rotational/kinetic temperature and the column density of ammonia for ortho and para species separately and on a position-by-position basis. We find rotational temperature and column density in the range 160-490 K and (1-4)x10^17 cm^-2, respectively. Our spatially-resolved images show that the highest (column) density and hottest gas is found in a northeast-southwest elongated ridge to the southeast of Source I. We have also measured the ortho-para ratio of ammonia, estimated to vary in the range 0.9-1.6. Enhancement of ortho with respect to para and the offset of hot ammonia emission peaks from known (proto)stellar sources provide evidence that the ammonia molecules have been released from dust grains into the gas-phase through the passage of shocks and not by stellar radiation. We propose that the combined effect of Source I's proper motion and its low-velocity outflow impinging on a pre-existing dense medium is responsible for the excitation of ammonia and the Orion Hot Core. Finally, we found for the first time evidence of a slow (5 km/s) and compact (1000 AU) outflow towards IRc7.Comment: To appear in Astrophysical Journal Letters Special Issue on the EVLA. 8 pages, 4 figure

Discourses of leadership: the changing context of primary education and the implications for the public sector

This paper explores how contextual factors function and shape leadership within a Primary School. The development of leaders and managers continues to be of interest to Human Resource Development (HRD) academics and practitioners. In recent years leadership has been viewed as a practice which can sustain growth. Within the field of education, government policies of school improvement use leadership and management to explain differing outcomes and measures of success. Since 1988 it has been regularly debated by both academics and policy-makers what the priorities of school leaders should be. Mainly over the last three decades owing to Educational reforms the role of headteachers and principals has changed dramatically. How a school is led and managed is regarded by both policy-makers and practitioners as a key factor in ensuring a school’s success. According to a systematic review conducted by Bell et al (2003:1), “there is a widespread, strongly held belief that school leadership makes a difference and that headteachers should be supported and trained to raise educational standards.” In addition, “the school as an organisational context for the work of leaders is complex” (Southworth 2004). Leaders in a school have to deal with multiple variables that change constantly in a variety of ways and as a result have to be conscious of the contextual factors impinging on their behaviour