1,042 research outputs found

    Spin squeezing of high-spin, spatially extended quantum fields

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    Investigations of spin squeezing in ensembles of quantum particles have been limited primarily to a subspace of spin fluctuations and a single spatial mode in high-spin and spatially extended ensembles. Here, we show that a wider range of spin-squeezing is attainable in ensembles of high-spin atoms, characterized by sub-quantum-limited fluctuations in several independent planes of spin-fluctuation observables. Further, considering the quantum dynamics of an f=1f=1 ferromagnetic spinor Bose-Einstein condensate, we demonstrate theoretically that a high degree of spin squeezing is attained in multiple spatial modes of a spatially extended quantum field, and that such squeezing can be extracted from spatially resolved measurements of magnetization and nematicity, i.e.\ the vector and quadrupole magnetic moments, of the quantum gas. Taking into account several experimental limitations, we predict that the variance of the atomic magnetization and nematicity may be reduced as far as 20 dB below the standard quantum limits.Comment: 18 pages, 5 figure

    Legal coercion, respect & reason-responsive agency

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    Legal coercion seems morally problematic because it is susceptible to the Hegelian objection that it fails to respect individuals in a way that is ‘due to them as men’. But in what sense does legal coercion fail to do so? And what are the grounds for this requirement to respect? This paper is an attempt to answer these questions. It argues that (a) legal coercion fails to respect individuals as reason-responsive agents; and (b) individuals ought to be respected as such in virtue of the fact that they are human beings. Thus it is in this sense that legal coercion fails to treat individuals with the kind of respect ‘due to them as men’.The Leverhulme Trust (ECF-2012-032); AHRC (AH/H015655/1

    Expression of the chemokine receptor CCR6 in human renal inflammation

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    Background. Nodular inflammatory cell infiltrates with defined microarchitecture, i.e. tertiary lymphoid organs, develop in the tubulointerstitium during chronic renal inflammation. CCR6 and the corresponding ligand CCL20 are involved in the formation of gut-associated lymphatic tissue. We hypothesized that CCR6 might be involved in the formation of nodular infiltrates in the kidney. Methods. CCR6- and CD20-positive B cells were localized in renal biopsies with IgA nephropathy (n = 13), membranous nephropathy (n = 12), crescentic glomerulonephritis (cGN, n = 11) and chronic interstitial nephritis (n = 13), and in pre-implantation biopsies as controls (n = 8). The mRNA expression of CCR6 and the ligand CCL20 was quantified by real-time RT-PCR in 51 renal biopsies of the same disease entities. Results. In the pre-transplant biopsies, CCR6 was expressed by endothelial cells of peritubular and glomerular capillaries. In patients with glomerulonephritis, infiltrating cells were positive particularly in areas of nodular inflammatory cell accumulations. A major part of the CCR6-positive cells were CD20-positive B cells, but a part of the CD3-positive T cells were also found to be positive. The constitutive expression of CCR6 on the endothelium of glomerular capillaries was lost in biopsies with progressive injury. Tubular epithelial cells expressed CCR6 in inflamed kidneys, most commonly on the basolateral side. Conclusions. CCR6 and the corresponding ligand CCL20 might therefore be involved in the recruitment of T and B cells to organized nodular infiltrates in chronic renal inflammation. The functional role of endothelial CCR6 needs to be evaluated in further studie

    GLIMPSE: I. A SIRTF Legacy Project to Map the Inner Galaxy

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    GLIMPSE (Galactic Legacy Infrared Mid-Plane Survey Extraordinaire), a SIRTF Legacy Science Program, will be a fully sampled, confusion-limited infrared survey of the inner two-thirds of the Galactic disk with a pixel resolution of \~1.2" using the Infrared Array Camera (IRAC) at 3.6, 4.5, 5.8, and 8.0 microns. The survey will cover Galactic latitudes |b| <1 degree and longitudes |l|=10 to 65 degrees (both sides of the Galactic center). The survey area contains the outer ends of the Galactic bar, the Galactic molecular ring, and the inner spiral arms. The GLIMPSE team will process these data to produce a point source catalog, a point source data archive, and a set of mosaicked images. We summarize our observing strategy, give details of our data products, and summarize some of the principal science questions that will be addressed using GLIMPSE data. Up-to-date documentation, survey progress, and information on complementary datasets are available on the GLIMPSE web site: www.astro.wisc.edu/glimpse.Comment: Description of GLIMPSE, a SIRTF Legacy project (Aug 2003 PASP, in press). Paper with full res.color figures at http://www.astro.wisc.edu/glimpse/glimpsepubs.htm

    Combined Cisplatinum and Laser Thermal Therapy for Palliation of Recurrent Head and Neck Tumors

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    In recent years endoscopically controlled laser-induced thermal therapy (LITT) has been increasingly accepted as a minimally invasive method for palliation of advanced or recurrent head and neck or gastrointestinal cancer. Previous studies have shown that adjuvant chemotherapy can potentiate endoscopic laser thermal ablation of obstructing tumors leading to improved palliation in advanced cancer patients. Eight patients with recurrent head and neck tumors volunteered to enroll as part of an ongoing phase II LITT clinical trial, and also elected to be treated with systemic chemotherapy (cisplatin, 80 mg/m2) followed 24 h later by palliative laser thermal ablation. Laser treatments were repeated in patients with residual disease or recurrence for a total of 27 LITT sessions. Four of the 8 patients treated with laser thermal chemotherapy remained alive after a median follow-up of 12 months. Of the 12 tumor sites treated, complete responses were located in the oral cavity (3), oropharynx (1), hypopharynx (1), maxillary sinus (1), and median survival for these patients was 9.5 months. This initial experience with cisplatinum-based laser chemotherapy indicates both safety and therapeutic potential for palliation of advanced head and neck cancer but this must be confirmed by longer follow-up in a larger cohort of patients

    Hybrid Baryons in Large-N_c QCD

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    We study the properties and couplings of hybrid baryons in the large-NcN_c expansion. These are color-neutral baryon states which contain in addition to NcN_c quarks also one constituent gluon. Hybrid baryons with both symmetric and mixed symmetric orbital wave functions are considered. We introduce a Hartree description for these states, similar to the one used by Witten for ordinary baryons. It is shown that the Hartree equations for Nc(Nc1)N_c (N_c-1) quarks for symmetric (mixed symmetric) states in these states coincide with those in ordinary baryons in the large-NcN_c limit. The energy due to the gluon field is of order ΛQCD\Lambda_{QCD}. Under the assumption of color confinement, our results prove the existence of hybrid baryons made up of heavy quarks in the large NcN_c limit and provides a justification for the constituent gluon picture of these states. The couplings of the hybrid baryons to mesons of arbitrary spin are computed in the quark model. Using constraints from the large NcN_c scaling laws for the meson-baryon scattering amplitudes, we write down consistency conditions for the meson couplings of the hybrid baryons. These consistency conditions are solved explicitly with results in agreement with those in the quark model for the respective couplings.Comment: 20 pages and one figure, ReVTe

    Anti-GBM Glomerulonephritis Involves IL-1 but Is Independent of NLRP3/ASC Inflammasome-Mediated Activation of Caspase-1

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    IL-1β and IL-18 are proinflammatory cytokines that contribute to renal immune complex disease, but whether IL-1β and IL-18 are mediators of intrinsic glomerular inflammation is unknown. In contrast to other cytokines the secretion of IL-1β and IL-18 requires a second stimulus that activates the inflammasome-ASC-caspase-1 pathway to cleave pro-IL-1β and -IL-18 into their mature and secretable forms. As the NLRP3 inflammasome and caspase-1 were shown to contribute to postischemic and postobstructive tubulointerstitial inflammation, we hypothesized a similar role for NLRP3, ASC, and caspase-1 in glomerular immunopathology. This concept was supported by the finding that lack of IL-1R1 reduced antiserum-induced focal segmental necrosis, crescent formation, and tubular atrophy when compared to wildtype mice. Lack of IL-18 reduced tubular atrophy only. However, NLRP3-, ASC- or caspase-1-deficiency had no significant effect on renal histopathology or proteinuria of serum nephritis. In vitro studies with mouse glomeruli or mesangial cells, glomerular endothelial cells, and podocytes did not reveal any pro-IL-1β induction upon LPS stimulation and no caspase-1 activation after an additional exposure to the NLRP3 agonist ATP. Only renal dendritic cells, which reside mainly in the tubulointerstitium, expressed pro-IL-1β and were able to activate the NLRP3-caspase-1 axis and secrete mature IL-1β. Together, the NLRP3-ASC-caspase-1 axis does not contribute to intrinsic glomerular inflammation via glomerular parenchymal cells as these cannot produce IL-1β during sterile inflammation

    Non-destructive optical measurement of relative phase between two Bose condensates

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    We study the interaction of light with two Bose condensates as an open quantum system. The two overlapping condensates occupy two different Zeeman sublevels and two driving light beams induce a coherent quantum tunneling between the condensates. We derive the master equation for the system. It is shown that stochastic simulations of the measurements of spontaneously scattered photons establish the relative phase between two Bose condensates, even though the condensates are initially in pure number states. These measurements are non-destructive for the condensates, because only light is scattered, but no atoms are removed from the system. Due to the macroscopic quantum interference the detection rate of photons depends substantially on the relative phase between the condensates. This may provide a way to distinguish, whether the condensates are initially in number states or in coherent states.Comment: 26 pages, RevTex, 8 postscript figures, 1 MacBinary eps-figur

    PTF10fqs: A Luminous Red Nova in the Spiral Galaxy Messier 99

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    The Palomar Transient Factory (PTF) is systematically charting the optical transient and variable sky. A primary science driver of PTF is building a complete inventory of transients in the local Universe (distance less than 200 Mpc). Here, we report the discovery of PTF10fqs, a transient in the luminosity "gap" between novae and supernovae. Located on a spiral arm of Messier 99, PTF 10fqs has a peak luminosity of Mr = -12.3, red color (g-r = 1.0) and is slowly evolving (decayed by 1 mag in 68 days). It has a spectrum dominated by intermediate-width H (930 km/s) and narrow calcium emission lines. The explosion signature (the light curve and spectra) is overall similar to thatof M85OT2006-1, SN2008S, and NGC300OT. The origin of these events is shrouded in mystery and controversy (and in some cases, in dust). PTF10fqs shows some evidence of a broad feature (around 8600A) that may suggest very large velocities (10,000 km/s) in this explosion. Ongoing surveys can be expected to find a few such events per year. Sensitive spectroscopy, infrared monitoring and statistics (e.g. disk versus bulge) will eventually make it possible for astronomers to unravel the nature of these mysterious explosions.Comment: 12 pages, 12 figures, Replaced with published versio

    Formation and Evolution of Planetary Systems: Placing Our Solar System in Context with Spitzer

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    We summarize the progress to date of our Legacy Science Program entitled "The Formation and Evolution of Planetary Systems" (FEPS) based on observations obtained with the Spitzer Space Telescope during its first year of operation. In addition to results obtained from our ground-based preparatory program and our early validation program, we describe new results from a survey for near-infrared excess emission from the youngest stars in our sample as well as a search for cold debris disks around sun-like stars. We discuss the implications of our findings with respect to current understanding of the formation and evolution of our own solar system.Comment: 8 postscript pages including 3 figures. To appear in "Spitzer New Views of the Cosmos" ASP Conference Series, eds. L. Armus et al. FEPS website at http://feps.as.arizona.ed
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