1,718 research outputs found

    Ectopic Expression of Zmiz1 Induces Cutaneous Squamous Cell Malignancies in a Mouse Model of Cancer

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    Cutaneous squamous cell carcinoma (SCC) is the second most common form of cancer in the human population, yet the underlying genetic mechanisms contributing to the disease are not well understood. We recently identified Zmiz1 as a candidate oncogene in nonmelanoma skin cancer through a transposon mutagenesis screen. Here we show that transposon-induced mutations in Zmiz1 drive expression of a truncated transcript that is similar to an alternative endogenous ZMIZ1 transcript found to be overexpressed in human SCCs relative to normal skin. We also describe an original mouse model of invasive keratoacanthoma driven by skin-specific expression of the truncated Zmiz1 transcript. Unlike most mouse models, Zmiz1-induced skin tumors develop rapidly and in the absence of promoting agents such as phorbol esters. In addition, we found that the alternative Zmiz1 isoform has greater protein stability than its full-length counterpart. Finally, we provide evidence that ZMIZ1 is overexpressed in a significant percentage of human breast, ovarian, and colon cancers in addition to human SCCs, suggesting that ZMIZ1 may play a broader role in epithelial cancers

    Rotational Velocities of Individual Components in Very Low Mass Binaries

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    We present rotational velocities for individual components of 11 very low mass (VLM) binaries with spectral types between M7 and L7.5. These results are based on observations taken with the near-infrared spectrograph, NIRSPEC, and the Keck II laser guide star adaptive optics system. We find that the observed sources tend to be rapid rotators (v sin i > 10 km s^(–1)), consistent with previous seeing-limited measurements of VLM objects. The two sources with the largest v sin i, LP 349–25B and HD 130948C, are rotating at ~30% of their break-up speed, and are among the most rapidly rotating VLM objects known. Furthermore, five binary systems, all with orbital semimajor axes ≟3.5 AU, have component v sin i values that differ by greater than 3σ. To bring the binary components with discrepant rotational velocities into agreement would require the rotational axes to be inclined with respect to each other, and that at least one component is inclined with respect to the orbital plane. Alternatively, each component could be rotating at a different rate, even though they have similar spectral types. Both differing rotational velocities and inclinations have implications for binary star formation and evolution. We also investigate possible dynamical evolution in the triple system HD 130948A–BC. The close binary brown dwarfs B and C have significantly different v sin i values. We demonstrate that components B and C could have been torqued into misalignment by the primary star, A, via orbital precession. Such a scenario can also be applied to another triple system in our sample, GJ 569A–Bab. Interactions such as these may play an important role in the dynamical evolution of VLM binaries. Finally, we note that two of the binaries with large differences in component v sin i, LP 349–25AB and 2MASS 0746+20AB, are also known radio sources

    Risk-based inspection as a cost-effective strategy to reduce human exposure to cysticerci of Taenia saginata in low-prevalence settings

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    Taenia saginata cysticercus is the larval stage of the zoonotic parasite Taenia saginata, with a life-cycle involving both cattle and humans. The public health impact is considered low. The current surveillance system, based on post-mortem inspection of carcasses has low sensitivity and leads to considerable economic burden. Therefore, in the interests of public health and food production efficiency, this study aims to explore the potential of risk-based and cost-effective meat inspection activities for the detection and control of T. saginata cysticercus in low prevalence settings

    Human rights and ethical reasoning : capabilities, conventions and spheres of public action

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    This interdisciplinary article argues that human rights must be understood in terms of opportunities for social participation and that social and economic rights are integral to any discussion of the subject. We offer both a social constructionist and a normative framework for a sociology of human rights which reaches beyond liberal individualism, combining insights from the work of Amartya Sen and from French convention theory. Following Sen, we argue that human rights are founded on the promotion of human capabilities as ethical demands shaped by public reasoning. Using French convention theory, we show how the terms of such deliberation are shaped by different constructions of collectively held values and the compromises reached between them. We conclude by demonstrating how our approach offers a new perspective on spheres of public action and the role these should play in promoting social cohesion, individual capabilities and human rights

    Low temperature transition to a superconducting phase in boron-doped silicon films grown on (001)-oriented silicon wafers

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    We report on a detailed analysis of the superconducting properties of boron-doped silicon films grown along the 001 direction by Gas Immersion Laser Doping. The doping concentration cB has been varied up to approx. 10 at.% by increasing the number of laser shots to 500. No superconductivity could be observed down to 40mK for doping level below 2.5 at.%. The critical temperature Tc then increased steeply to reach 0.6K for cB = 8 at%. No hysteresis was found for the transitions in magnetic field, which is characteristic of a type II superconductor. The corresponding upper critical field Hc2(0) was on the order of 1000 G, much smaller than the value previously reported by Bustarret et al. in Nature (London) 444, 465 (2006).Comment: 4 pages including 4 figures, submitted to PRB-Rapid Communicatio

    DISCOVERY OF A LOW-LUMINOSITY, TIGHT SUBSTELLAR BINARY AT THE T/Y TRANSITION

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    We have discovered that the brown dwarf WISEJ014656.66+423410.0 is a close binary (0.0875±\pm0.0021 arcsec, 0.93−0.16+0.12^{+0.12}_{-0.16} AU) from Keck laser guide star adaptive optics imaging. Our photometry for this system reveals that both components are less luminous than those in any known substellar binary. Combining a new integrated-light spectrum (T9p) and resolved YJH-band photometry from Keck allows us to perform spectral decomposition and assign component types of T9 and Y0. Many of the unusual features in the spectrum might be explained by high surface gravity: Y-band peak broadened to the blue; J-band peak broadened to the red; H-band peak shifted slightly to the red; and red Y-J colors. Interestingly, the very low component luminosities imply that the T9 primary is unexpectedly cold (TeffT_{\rm eff} = 345±\pm45 K assuming an age of 10 Gyr), making it ≈\approx100 K cooler than any other late-T dwarf and comparable to Y dwarfs. One intriguing explanation for this apparent discrepancy is that the J- and H-band spectral features that trigger the transition from T to Y spectral types are highly gravity-dependent. This can be tested directly in the very near future by orbit monitoring. We constrain the orbital period to be â‰Č\lesssim10 yr by combining evolutionary model-based mass estimates for the components (≈\approx12−-21 MJupM_{\rm Jup}, 1σ\sigma at 10 Gyr) with a statistical constraint on the semimajor axis (â‰Č\lesssim1.3 AU). Such a period is shorter than any other known T/Y transition binary, meaning that WISEJ0146+4234AB will likely yield a dynamical mass within the next few years.Comment: Accepted to ApJ (2015 Feb 14); 24 pages, 4 figures, 5 table

    Deep search for companions to probable young brown dwarfs

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    We have obtained high contrast images of four nearby, faint, and very low mass objects 2MASSJ04351455-1414468, SDSSJ044337.61+000205.1, 2MASSJ06085283-2753583 and 2MASSJ06524851-5741376 (here after 2MASS0435-14, SDSS0443+00, 2MASS0608-27 and 2MASS0652-57), identified in the field as probable isolated young brown dwarfs. Our goal was to search for binary companions down to the planetary mass regime. We used the NAOS-CONICA adaptive optics instrument (NACO) and its unique capability to sense the wavefront in the near-infrared to acquire sharp images of the four systems in Ks, with a field of view of 28"*28". Additional J and L' imaging and follow-up observations at a second epoch were obtained for 2MASS0652-57. With a typical contrast DKs= 4.0-7.0 mag, our observations are sensitive down to the planetary mass regime considering a minimum age of 10 to 120 Myr for these systems. No additional point sources are detected in the environment of 2MASS0435-14, SDSS0443+00 and 2MASS0608-27 between 0.1-12" (i.e about 2 to 250 AU at 20 pc). 2MASS0652-57 is resolved as a \sim230 mas binary. Follow-up observations reject a background contaminate, resolve the orbital motion of the pair, and confirm with high confidence that the system is physically bound. The J, Ks and L' photometry suggest a q\sim0.7-0.8 mass ratio binary with a probable semi-major axis of 5-6 AU. Among the four systems, 2MASS0652-57 is probably the less constrained in terms of age determination. Further analysis would be necessary to confirm its youth. It would then be interesting to determine its orbital and physical properties to derive the system's dynamical mass and to test evolutionary model predictions.Comment: Research note, 5 pages, 2 tables and 3 figures, accepted to A&

    TESTING the BINARY TRIGGER HYPOTHESIS in FUors

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    We present observations of three FU Orionis objects (hereafter, FUors) with nonredundant aperture-mask interferometry at 1.59 ÎŒm and 2.12 ÎŒm that probe for binary companions on the scale of the protoplanetary disk that feeds their accretion outbursts. We do not identify any companions to V1515 Cyg or HBC 722, but we do resolve a close binary companion to V1057 Cyg that is at the diffraction limit (ρ=58.3±1.4\rho =58.3\pm 1.4 mas or 30 ± 5 au) and currently much fainter than the outbursting star (ΔKâ€Č=3.34±0.10{\rm{\Delta }}K^{\prime} =3.34\pm 0.10 mag). Given the flux excess of the outbursting star, we estimate that the mass of the companion (M∌0.25M⊙M\sim 0.25{M}_{\odot }) is similar to or slightly below that of the FUor itself, and therefore it resembles a typical T Tauri binary system. Our observations only achieve contrast limits of ΔKâ€Č∌4{\rm{\Delta }}K^{\prime} \sim 4 mag, and hence we are only sensitive to companions that were near or above the pre-outburst luminosity of the FUors. It remains plausible that FUor outbursts could be tied to the presence of a close binary companion. However, we argue from the system geometry and mass reservoir considerations that these outbursts are not directly tied to the orbital period (i.e., occurring at periastron passage), but instead must only occur infrequently

    The Young L Dwarf 2MASS J11193254-1137466 Is a Planetary-mass Binary

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    We have discovered that the extremely red, low-gravity L7 dwarf 2MASS J11193254-1137466 is a 0.14" (3.6 AU) binary using Keck laser guide star adaptive optics imaging. 2MASS J11193254-1137466 has previously been identified as a likely member of the TW Hydrae Association (TWA). Using our updated photometric distance and proper motion, a kinematic analysis based on the BANYAN II model gives an 82% probability of TWA membership. At TWA's 10±\pm3 Myr age and using hot-start evolutionary models, 2MASS J11193254-1137466AB is a pair of 3.7−0.9+1.23.7^{+1.2}_{-0.9} MJupM_{\rm Jup} brown dwarfs, making it the lowest-mass binary discovered to date. We estimate an orbital period of 90−50+8090^{+80}_{-50} years. One component is marginally brighter in KK band but fainter in JJ band, making this a probable flux-reversal binary, the first discovered with such a young age. We also imaged the spectrally similar TWA L7 dwarf WISEA J114724.10-204021.3 with Keck and found no sign of binarity. Our evolutionary model-derived TeffT_{\rm eff} estimate for WISEA J114724.10-204021.3 is ≈\approx230 K higher than for 2MASS J11193254-1137466AB, at odds with their spectral similarity. This discrepancy suggests that WISEA J114724.10-204021.3 may actually be a tight binary with masses and temperatures very similar to 2MASS J11193254-1137466AB, or further supporting the idea that near-infrared spectra of young ultracool dwarfs are shaped by factors other than temperature and gravity. 2MASS J11193254-1137466AB will be an essential benchmark for testing evolutionary and atmospheric models in the young planetary-mass regime.Comment: Accepted to ApJ Letters. 8 pages, 3 figures, 2 table

    A wildland fire model with data assimilation

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    A wildfire model is formulated based on balance equations for energy and fuel, where the fuel loss due to combustion corresponds to the fuel reaction rate. The resulting coupled partial differential equations have coefficients that can be approximated from prior measurements of wildfires. An ensemble Kalman filter technique with regularization is then used to assimilate temperatures measured at selected points into running wildfire simulations. The assimilation technique is able to modify the simulations to track the measurements correctly even if the simulations were started with an erroneous ignition location that is quite far away from the correct one.Comment: 35 pages, 12 figures; minor revision January 2008. Original version available from http://www-math.cudenver.edu/ccm/report
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