158 research outputs found
My Blue Ridge Mountain Home
https://digitalcommons.library.umaine.edu/mmb-vp/7260/thumbnail.jp
Infrared Non-detection of Fomalhaut b -- Implications for the Planet Interpretation
The nearby A4-type star Fomalhaut hosts a debris belt in the form of an
eccentric ring, which is thought to be caused by dynamical influence from a
giant planet companion. In 2008, a detection of a point-source inside the inner
edge of the ring was reported and was interpreted as a direct image of the
planet, named Fomalhaut b. The detection was made at ~600--800 nm, but no
corresponding signatures were found in the near-infrared range, where the bulk
emission of such a planet should be expected. Here we present deep observations
of Fomalhaut with Spitzer/IRAC at 4.5 um, using a novel PSF subtraction
technique based on ADI and LOCI, in order to substantially improve the Spitzer
contrast at small separations. The results provide more than an order of
magnitude improvement in the upper flux limit of Fomalhaut b and exclude the
possibility that any flux from a giant planet surface contributes to the
observed flux at visible wavelengths. This renders any direct connection
between the observed light source and the dynamically inferred giant planet
highly unlikely. We discuss several possible interpretations of the total body
of observations of the Fomalhaut system, and find that the interpretation that
best matches the available data for the observed source is scattered light from
transient or semi-transient dust cloud.Comment: 12 pages, 4 figures, ApJ 747, 166. V2: updated acknowledgments and
reference
Prospectus, November 9, 1988
https://spark.parkland.edu/prospectus_1988/1028/thumbnail.jp
Prospectus, November 2, 1988
https://spark.parkland.edu/prospectus_1988/1027/thumbnail.jp
COVID-19: Beyond Washing Your Hands and Social Distancing
A pandemic due to the outbreak of the COVID-19 virus was declared as of March 2020. The authors provide perspective towards preventing and/or mitigating the impact of contracting the virus known as COVID-19. The authors posit straightforward strategies that an individual could implement that may decrease the likelihood of developing COVID-19, help lessen the severity of the symptoms related to the COVID-19 and potentially mitigate the transmission of the virus. The authors consider their comments as food for thought and not as professional medical advice. If you believe you have contracted the COVID-19 virus seek the advice of your healthcare provider
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Repurposing Albendazole: new potential as a chemotherapeutic agent with preferential activity against HPV-negative head and neck squamous cell cancer.
Albendazole is an anti-helminthic drug that has been shown to exhibit anti-cancer properties, however its activity in head and neck squamous cell cancer (HNSCC) was unknown. Using a series of in vitro assays, we assessed the ability of albendazole to inhibit proliferation in 20 HNSCC cell lines across a range of albendazole doses (1 nM-10 μM). Cell lines that responded to treatment were further examined for cell death, inhibition of migration and cell cycle arrest. Thirteen of fourteen human papillomavirus-negative HNSCC cell lines responded to albendazole, with an average IC50 of 152 nM. In contrast, only 3 of 6 human papillomavirus-positive HNSCC cell lines responded. Albendazole treatment resulted in apoptosis, inhibition of cell migration, cell cycle arrest in the G2/M phase and altered tubulin distribution. Normal control cells were not measurably affected by any dose tested. This study indicates that albendazole acts to inhibit the proliferation of human papillomavirus-negative HNSCC cell lines and thus warrants further study as a potential chemotherapeutic agent for patients suffering from head and neck cancer
Probing for Exoplanets Hiding in Dusty Debris Disks: Disk Imaging, Characterization, and Exploration with HST/STIS Multi-Roll Coronagraphy
Spatially resolved scattered-light images of circumstellar (CS) debris in
exoplanetary systems constrain the physical properties and orbits of the dust
particles in these systems. They also inform on co-orbiting (but unseen)
planets, systemic architectures, and forces perturbing starlight-scattering CS
material. Using HST/STIS optical coronagraphy, we have completed the
observational phase of a program to study the spatial distribution of dust in
ten CS debris systems, and one "mature" protoplanetrary disk all with HST
pedigree, using PSF-subtracted multi-roll coronagraphy. These observations
probe stellocentric distances > 5 AU for the nearest stars, and simultaneously
resolve disk substructures well beyond, corresponding to the giant planet and
Kuiper belt regions in our Solar System. They also disclose diffuse very
low-surface brightness dust at larger stellocentric distances. We present new
results inclusive of fainter disks such as HD92945 confirming, and better
revealing, the existence of a narrow inner debris ring within a larger diffuse
dust disk. Other disks with ring-like sub-structures, significant asymmetries
and complex morphologies include: HD181327 with a posited spray of ejecta from
a recent massive collision in an exo-Kuiper belt; HD61005 suggested interacting
with the local ISM; HD15115 & HD32297, discussed also in the context of
environmental interactions. These disks, and HD15745, suggest debris system
evolution cannot be treated in isolation. For AU Mic's edge-on disk,
out-of-plane surface brightness asymmetries at > 5 AU may implicate one or more
planetary perturbers. Time resolved images of the MP Mus proto-planetary disk
provide spatially resolved temporal variability in the disk illumination. These
and other new images from our program enable direct inter-comparison of the
architectures of these exoplanetary debris systems in the context of our own
Solar System.Comment: 109 pages, 43 figures, accepted for publication in the Astronomical
Journa
Doctor of Education Newsletter 2019
WSU Doctor of Education Inaugural Cohort 2019
Winona State University has an astounding reputation for educational practitioner preparation programs in the College of Education. As the summer of 2019 commences, a new journey begins for the inaugural cohort of doctoral students who embark on their quest to obtain Doctor of Education degrees.https://openriver.winona.edu/educationeddnewsletters/1000/thumbnail.jp
A Digital Atlas to Characterize the Mouse Brain Transcriptome
Massive amounts of data are being generated in an effort to represent for the brain the expression of all genes at cellular resolution. Critical to exploiting this effort is the ability to place these data into a common frame of reference. Here we have developed a computational method for annotating gene expression patterns in the context of a digital atlas to facilitate custom user queries and comparisons of this type of data. This procedure has been applied to 200 genes in the postnatal mouse brain. As an illustration of utility, we identify candidate genes that may be related to Parkinson disease by using the expression of a dopamine transporter in the substantia nigra as a search query pattern. In addition, we discover that transcription factor Rorb is down-regulated in the barrelless mutant relative to control mice by quantitative comparison of expression patterns in layer IV somatosensory cortex. The semi-automated annotation method developed here is applicable to a broad spectrum of complex tissues and data modalities
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