1,884 research outputs found

    Tracking the Martian CO2 Polar Ice Caps in Infrared Images

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    Researchers at NASA s Jet Propulsion Laboratory have developed a method for automatically tracking the polar caps on Mars as they advance and recede each year (see figure). The seasonal Mars polar caps are composed mainly of CO2 ice and are therefore cold enough to stand out clearly in infrared data collected by the Thermal Emission Imaging System (THEMIS) onboard the Mars Odyssey spacecraft. The Bimodal Image Temperature (BIT) histogram analysis algorithm analyzes raw, uncalibrated data to identify images that contain both "cold" ("polar cap") and "warm" ("not polar cap") pixels. The algorithm dynamically identifies the temperature that separates these two regions. This flexibility is critical, because in the absence of any calibration, the threshold temperature can vary significantly from image to image. Using the identified threshold, the algorithm classifies each pixel in the image as "polar cap" or "not polar cap," then identifies the image row that contains the spatial transition from "polar cap" to "not polar cap." While this method is useful for analyzing data that has already been returned by THEMIS, it has even more significance with respect to data that has not yet been collected. Instead of seeking the polar cap only in specific, targeted images, the simplicity and efficiency of this method makes it feasible for direct, onboard use. That is, THEMIS could continuously monitor its observations for any detections of the polar-cap edge, producing detections over a wide range of spatial and temporal conditions. This effort can greatly contribute to our understanding of long-term climatic change on Mars

    Semi-Supervised Data Summarization: Using Spectral Libraries to Improve Hyperspectral Clustering

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    Hyperspectral imagers produce very large images, with each pixel recorded at hundreds or thousands of different wavelengths. The ability to automatically generate summaries of these data sets enables several important applications, such as quickly browsing through a large image repository or determining the best use of a limited bandwidth link (e.g., determining which images are most critical for full transmission). Clustering algorithms can be used to generate these summaries, but traditional clustering methods make decisions based only on the information contained in the data set. In contrast, we present a new method that additionally leverages existing spectral libraries to identify materials that are likely to be present in the image target area. We find that this approach simultaneously reduces runtime and produces summaries that are more relevant to science goals

    Models of Dynamical Supersymmetry Breaking with Gauged U(1)RU(1)_R Symmetry

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    We present simple models of dynamical supersymmetry breaking with gauged U(1)_R symmetry. The minimal supersymmetric standard model and supersymmetric SU(5) GUT are considered as the visible sector. The anomaly cancellation conditions for U(1)_R are investigated in detail and simple solutions of the R-charge assignments are found. We show that this scenario of dynamical supersymmetry breaking is phenomenologically viable with the gravitino mass of order 1 TeV or 10 TeV.Comment: 15 pages, uses REVTEX macro, No figure

    Towards Onboard Orbital Tracking of Seasonal Polar Volatiles on Mars

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    Current conditions on Mars support both a residual polar cap, composed mainly of water ice, and a seasonal cap, composed of CO2, which appears and disappears each winter. Kieffer and Titus characterized the recession of the seasonal south polar cap using an arctangent curve fit based on data from the Thermal Emission Spectrometer on Mars Global Surveyor [1]. They also found significant interannual deviations, at the regional scale, in the recession rate [2]. Further observations will enable the refinement of our models of polar cap evolution in both hemispheres. We have developed the Bimodal Image Temperature (BIT) Histogram Analysis method for the automated detection and tracking of the seasonal polar ice caps on Mars. It is specifically tailored for possible use onboard a spacecraft. We have evaluated BIT on uncalibrated data collected by the Thermal Emission Imaging System (THEMIS) instrument [3] on the Mars Odyssey spacecraft. In this paper, we focus on the northern seasonal cap, but our approach is directly applicable to the future analysis of the southern seasonal ice cap as well

    Minimal Gaugino Mediation

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    We propose Minimal Gaugino Mediation as the simplest known solution to the supersymmetric flavor and CP problems. The framework predicts a very minimal structure for the soft parameters at ultra-high energies: gaugino masses are unified and non-vanishing whereas all other soft supersymmetry breaking parameters vanish. We show that this boundary condition naturally arises from a small extra dimension and present a complete model which includes a new extra-dimensional solution to the mu problem. We briefly discuss the predicted superpartner spectrum as a function of the two parameters of the model. The commonly ignored renormalization group evolution above the GUT scale is crucial to the viability of Minimal Gaugino Mediation but does not introduce new model dependence.Comment: LaTeX, 16 pages, 4 figures, running of the bottom and tau Yukawas included, plots revise

    A Constrained Standard Model from a Compact Extra Dimension

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    A SU(3) \times SU(2) \times U(1) supersymmetric theory is constructed with a TeV sized extra dimension compactified on the orbifold S^1/(Z_2 \times Z_2'). The compactification breaks supersymmetry leaving a set of zero modes which correspond precisely to the states of the 1 Higgs doublet standard model. Supersymmetric Yukawa interactions are localized at orbifold fixed points. The top quark hypermultiplet radiatively triggers electroweak symmetry breaking, yielding a Higgs potential which is finite and exponentially insensitive to physics above the compactification scale. This potential depends on only a single free parameter, the compactification scale, yielding a Higgs mass prediction of 127 \pm 8 GeV. The masses of the all superpartners, and the Kaluza-Klein excitations are also predicted. The lightest supersymmetric particle is a top squark of mass 197 \pm 20 GeV. The top Kaluza-Klein tower leads to the \rho parameter having quadratic sensitivity to unknown physics in the ultraviolet.Comment: 31 pages, Latex, 2 eps figures, minor correction

    Molecular Characterization of Growth Hormone-producing Tumors in the GC Rat Model of Acromegaly

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    D.A.C. was supported by the Nicolás Monardes program of the Andalusian Ministry of Health (C-0015-2014) and by a grant from the Andalusian Ministry of Science and Innovation (CTS-7478). A.S-M and A.L.C were supported by grants from the ISCIII-Subdirección General de Evaluación y Fomento de la Investigación co-funded with Fondos FEDER (PI12/0143 and PI13/02043, respectively) and the Andalusian Regional Government (CTS-444) and a grant from Pfizer Spain. R.L.C. was supported by a grant from Andalusian Ministry of Health (PI0302-2012). R.M.L. was supported by grants from Proyecto de Investigación en Salud (FIS) PI13- 00651 (funded by Instituto de Salud Carlos III), CTS-1406, PI-0639-2012, BIO-0139 (funded by Junta de Andalucía) and by Ayuda Merck Serono 2013. J. P. C. was funded by a grant (BFU2013-43282-R) from Ministerio de Economía y Competitividad. CIBER is an initiative of Instituto de Salud Carlos III, Ministerio de Sanidad, Servicios Sociales e Igualdad, Spain. J.F.M.R. is supported by the “Sara Borrell” program from the Instituto de Salud Carlos III. R.M. Luque and J.P. Castaño have received grants and lecture fees from Ipsen and Novartis. E. Venegas-Moreno and A. Soto-Moreno received grants and lecture fees from Ipsen, Novartis and Pfizer. A. Leal-Cerro received grants from Novartis and Pfizer. David Cano received a grant from Novartis

    Democracy, Technology and The Civil Rights Project

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    Democracy has been defined as a political system in which the whole people make, and are entitled to make, the basic determining decisions on important matters of public policy. While the United States is often touted as the world\u27s leading proponent of democracy, many U.S. citizens find themselves unable to engage in one of the central acts of democracy—creating public voice through public engagement. Public engagement in the United States is constrained by our inability to talk through our shared, complementary and divergent values. This lack of public engagement and our inability to speak in a public voice is also driven by a cultural tendency to reduce complex public issues to simple for or against policy positions. The process of building a public voice in the United States is further complicated by the vast racial, ethnic, linguistic and economic diversity, and the imbalance of power that exist among these separate sectors of our society. The history of this country is replete with the struggles of people to overcome these power imbalances and create opportunities for their voices to become an integral part of the public voice. But, as the 21st century approaches, these same citizens find themselves on the brink of a new battle over citizen participation. This battle is being defined around access to and use of technology. Currently, most Americans are merely bystanders watching the rapid advances in technology shift the political, economic, and social terrain in which their viability as citizens is being determined. For members of the African-American community, and indeed for all communities of color and for economically disadvantaged communities, their ability to participate as equal citizens will now, in part, depend upon their ability to shape the technological world that is redefining the concept of public discourse and public involvement in the political process

    Yukawa Unified Supersymmetric SO(10) Model: Cosmology, Rare Decays and Collider Searches

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    It has recently been pointed out that viable sparticle mass spectra can be generated in Yukawa unified SO(10) supersymmetric grand unified models consistent with radiative breaking of electroweak symmetry. Model solutions are obtained only if tanβ50\tan\beta \sim 50, μ<0\mu <0 and positive DD-term contributions to scalar masses from SO(10) gauge symmetry breaking are used. In this paper, we attempt to systematize the parameter space regions where solutions are obtained. We go on to calculate the relic density of neutralinos as a function of parameter space. No regions of the parameter space explored were actually cosmologically excluded, and very reasonable relic densities were found in much of parameter space. Direct neutralino detection rates could exceed 1 event/kg/day for a 73^{73}Ge detector, for low values of GUT scale gaugino mass m1/2m_{1/2}. We also calculate the branching fraction for bsγb\to s \gamma decays, and find that it is beyond the 95% CL experimental limits in much, but not all, of the parameter space regions explored. However, recent claims have been made that NLO effects can reverse the signs of certain amplitudes in the bsγb\to s\gamma calculation, leading to agreement between theory and experiment in Yukawa unified SUSY models. For the Fermilab Tevatron collider, significant regions of parameter space can be explored via bbˉAb\bar{b}A and bbˉHb\bar{b}H searches. There also exist some limited regions of parameter space where a trilepton signal can be seen at TeV33. Finally, there exist significant regions of parameter space where direct detection of bottom squark pair production can be made, especially for large negative values of the GUT parameter A0A_0.Comment: Added comparison to Blazek/Raby results and added Comments on de Boer et al. b->s gamma result
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