67 research outputs found
'Follow me': a web-based, location-sharing architecture for large, indoor environments
We leverage the ubiquity of bluetooth-enabled devices and propose a decentralized, web-based architecture that allows users to share their location by following each other in the style of Twitter. We demonstrate a prototype that operates in a large building which generates a dataset of detected bluetooth devices at a rate of ~30 new devices per day, including the respective location where they were last detected. Users then query the dataset using their unique bluetooth ID and share their current location with their followers by means of unique URIs that they control. Our separation between producers (the building) and consumers (the users) of bluetooth device location data allows us to create socially-aware applications that respect user's privacy while limiting the software necessary to run on mobile devices to just a web browser
The transcription factor FOXO3a is a crucial cellular target of gefitinib (Iressa) in breast cancer cells
Gefitinib is a specific inhibitor of the epidermal growth factor receptor (EGFR) that causes growth delay in cancer cell lines and human tumor xenografts expressing high levels of EGFR. An understanding of the downstream cellular targets of gefitinib will allow the discovery of biomarkers for predicting outcomes and monitoring anti-EGFR therapies and provide information for key targets for therapeutic intervention. In this study, we investigated the role of FOXO3a in gefitinib action and resistance. Using two gefitinib-sensitive (i.e., BT474 and SKBR3) as well as three other resistant breast carcinoma cell lines (i.e., MCF-7, MDA-MB-231, and MDA-MB-453), we showed that gefitinib targets the transcription factor FOXO3a to mediate cell cycle arrest and cell death in sensitive breast cancer cells. In the sensitive cells, gefitinib treatment causes cell cycle arrest predominantly at the G(0)-G(1) phase and apoptosis, which is associated with FOXO3a dephosphorylation at Akt sites and nuclear translocation, whereas in the resistant cells, FOXO3a stays phosphorylated and remains in the cytoplasm. The nuclear accumulation of FOXO3a in response to gefitinib was confirmed in tumor tissue sections from breast cancer patients presurgically treated with gefitinib as monotherapy. We also showed that knockdown of FOXO3a expression using small interfering RNA (siRNA) can rescue sensitive BT474 cells from gefitinib-induced cell-proliferative arrest, whereas reintroduction of active FOXO3a in resistant MDA-MB-231 cells can at least partially restore cell-proliferative arrest and sensitivity to gefitinib. These results suggest that the FOXO3a dephosphorylation and nuclear localization have a direct role in mediating the gefitinib-induced proliferative arrest and in determining sensitivity to gefitinib.Supported by the German Cancer Aide Foundation (J. Krol)and the Association of International Cancer Research (R. Francis).Andrew Sunters and Andreas Polychronic were fellows funded by CancerResearch UK. Andre Albergaria is a recipient of a grant from Fundação para a Ciência e a Tecnologia, Portugal. This work was sponsored by theBreast Cancer Research Trust and Cancer Research U
Structural analysis of massive galaxies using HST deep imaging at z < 0.5
Taking advantage of HST CANDELS data, we analyze the lowest redshift (z<0.5)
massive galaxies in order to disentangle their structural constituents and
study possible faint non-axis-symmetric features. Due to the excellent HST
spatial resolution for intermediate-z objects, they are hard to model by purely
automatic parametric fitting algorithms. We performed careful single and double
S\'ersic fits to their galaxy surface brightness profiles. We also compare the
model color profiles with the observed ones and also derive multi-component
global effective radii attempting to obtain a better interpretation of the
mass-size relation. Additionally, we test the robustness of our measured
structural parameters via simulations. We find that the S\'ersic index does not
offer a good proxy for the visual morphological type for our sample of massive
galaxies. Our derived multi-component effective radii give a better description
of the size of our sample galaxies than those inferred from single S\'ersic
models with GALFIT. Our galaxy population lays on the scatter of the local
mass-size relation, indicating that these massive galaxies do not experience a
significant growth in size since z~0.5. Interestingly the few outliers are
late-type galaxies, indicating that spheroids must reach the local mass-size
relation earlier. For most of our sample galaxies, both single and
multi-component S\'ersic models with GALFIT show substantial systematic
deviations from the observed SBPs in the outskirts. These residuals may be
partly due to several factors, namely a non-optimal data reduction for low
surface brightness features, the existence of prominent stellar haloes for
massive galaxies and could also arise from conceptual shortcomings of
parametric 2D image decomposition tools. They consequently propagate into
galaxy color profiles
The JWST Early Release Science Program for the Direct Imaging and Spectroscopy of Exoplanetary Systems
The direct characterization of exoplanetary systems with high-contrast imaging is among the highest priorities for the broader exoplanet community. As large space missions will be necessary for detecting and characterizing exo-Earth twins, developing the techniques and technology for direct imaging of exoplanets is a driving focus for the community. For the first time, JWST will directly observe extrasolar planets at mid-infrared wavelengths beyond 5 μm, deliver detailed spectroscopy revealing much more precise chemical abundances and atmospheric conditions, and provide sensitivity to analogs of our solar system ice-giant planets at wide orbital separations, an entirely new class of exoplanet. However, in order to maximize the scientific output over the lifetime of the mission, an exquisite understanding of the instrumental performance of JWST is needed as early in the mission as possible. In this paper, we describe our 55 hr Early Release Science Program that will utilize all four JWST instruments to extend the characterization of planetary-mass companions to ∼15 μm as well as image a circumstellar disk in the mid-infrared with unprecedented sensitivity. Our program will also assess the performance of the observatory in the key modes expected to be commonly used for exoplanet direct imaging and spectroscopy, optimize data calibration and processing, and generate representative data sets that will enable a broad user base to effectively plan for general observing programs in future Cycles
The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems: Best Practices for Data Collection in Cycle 2 and Beyond
We present a set of recommended best practices for JWST data collection for
members of the community focussed on the direct imaging and spectroscopy of
exoplanetary systems. These findings and recommendations are based on the early
analysis of the JWST Early Release Science Program 1386, "High-Contrast Imaging
of Exoplanets and Exoplanetary Systems with JWST." Our goal is for this
information to be useful for observers in preparation of JWST proposals for
Cycle 2 and beyond. In addition to compiling a set of best practices from our
ERS program, in a few cases we also draw on the expertise gained within the
instrument commissioning programs, as well as include a handful of data
processing best practices. We anticipate that this document will be regularly
updated and resubmitted to arXiv.org to ensure that we have distributed our
knowledge of best-practices for data collection as widely and efficiently as
possible.Comment: Not yet submitted for publication. Intended only to be a community
resource for JWST Cycle 2 proposal
The JWST Early-Release Science Program for Direct Observations of Exoplanetary Systems Ii: A 1 To 20 Μm Spectrum of the Planetary-Mass Companion Vhs 1256-1257 B
We present the highest fidelity spectrum to date of a planetary-mass object. VHS 1256 b is a (∼8″, a = 150 au), young, planetary-mass companion that shares photometric colors and spectroscopic features with the directly imaged exoplanets HR 8799c, d, and e. As an L-to-T transition object, VHS 1256 b exists along the region of the color-magnitude diagram where substellar atmospheres transition from cloudy to clear. We observed VHS 1256 b with JWST\u27s NIRSpec IFU and MIRI MRS modes for coverage from 1 to 20 μm at resolutions of ∼1000-3700. Water, methane, carbon monoxide, carbon dioxide, sodium, and potassium are observed in several portions of the JWST spectrum based on comparisons from template brown dwarf spectra, molecular opacities, and atmospheric models. The spectral shape of VHS 1256 b is influenced by disequilibrium chemistry and clouds. We directly detect silicate clouds, the first such detection reported for a planetary-mass companion
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