1,896 research outputs found
Tracking the Martian CO2 Polar Ice Caps in Infrared Images
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
Models of Dynamical Supersymmetry Breaking with Gauged Symmetry
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
Semi-Supervised Data Summarization: Using Spectral Libraries to Improve Hyperspectral Clustering
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
Towards Onboard Orbital Tracking of Seasonal Polar Volatiles on Mars
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
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
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
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
Novel prokaryotic expression of thioredoxin-fused insulinoma associated protein tyrosine phosphatase 2 (IA-2), its characterization and immunodiagnostic application
Background
The insulinoma associated protein tyrosine phosphatase 2 (IA-2) is one of the immunodominant autoantigens involved in the autoimmune attack to the beta-cell in Type 1 Diabetes Mellitus. In this work we have developed a complete and original process for the production and recovery of the properly folded intracellular domain of IA-2 fused to thioredoxin (TrxIA-2ic) in Escherichia coli GI698 and GI724 strains. We have also carried out the biochemical and immunochemical characterization of TrxIA-2icand design variants of non-radiometric immunoassays for the efficient detection of IA-2 autoantibodies (IA-2A).
Results
The main findings can be summarized in the following statements: i) TrxIA-2ic expression after 3 h of induction on GI724 strain yielded ≈ 10 mg of highly pure TrxIA-2ic/L of culture medium by a single step purification by affinity chromatography, ii) the molecular weight of TrxIA-2ic (55,358 Da) could be estimated by SDS-PAGE, size exclusion chromatography and mass spectrometry, iii) TrxIA-2ic was properly identified by western blot and mass spectrometric analysis of proteolytic digestions (63.25 % total coverage), iv) excellent immunochemical behavior of properly folded full TrxIA-2ic was legitimized by inhibition or displacement of [35S]IA-2 binding from IA-2A present in Argentinian Type 1 Diabetic patients, v) great stability over time was found under proper storage conditions and vi) low cost and environmentally harmless ELISA methods for IA-2A assessment were developed, with colorimetric or chemiluminescent detection.
Conclusions
E. coli GI724 strain emerged as a handy source of recombinant IA-2ic, achieving high levels of expression as a thioredoxin fusion protein, adequately validated and applicable to the development of innovative and cost-effective immunoassays for IA-2A detection in most laboratories.Fil: Guerra, Luciano Lucas. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni; ArgentinaFil: Faccinetti, Natalia Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni; ArgentinaFil: Trabucchi, Aldana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni; ArgentinaFil: Rovitto, Bruno David. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni; ArgentinaFil: Sabljic, Adriana Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni; ArgentinaFil: Poskus, Edgardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni; ArgentinaFil: Iacono, Ruben Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni; ArgentinaFil: Valdez, Silvina Noemi. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni; Argentin
Yukawa Unified Supersymmetric SO(10) Model: Cosmology, Rare Decays and Collider Searches
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 , and positive -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 Ge detector, for low values of GUT scale
gaugino mass . We also calculate the branching fraction for 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 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
and 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 .Comment: Added comparison to Blazek/Raby results and added Comments on de Boer
et al. b->s gamma result
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