3,687 research outputs found
Methane Flammability
This slide presentation for the Natural Sciences Poster Session at Parkland College summarizes a study conducted to determine which range of mixtures between Oxygen, Methane, Nitrogen and Carbon Dioxide are flammable, and also discovered the influence of certain components on overall flammability
C++ RISK Simulation to Generate AI
For this A with Honors project, the student set out to create a way to run thousands of simulations for the board game, RISK, supplying information for the game player to be able to make more strategic decisions when playing the game
S17RS SGB No. 7 (Amend Student Government Constitution)
To Amend The Student Government Constitutio
Stellar Intensity Interferometry: Imaging capabilities of air Cherenkov telescope arrays
Sub milli-arcsecond imaging in the visible band will provide a new
perspective in stellar astrophysics. Even though stellar intensity
interferometry was abandoned more than 40 years ago, it is capable of imaging
and thus accomplishing more than the measurement of stellar diameters as was
previously thought. Various phase retrieval techniques can be used to
reconstruct actual images provided a sufficient coverage of the interferometric
plane is available. Planned large arrays of Air Cherenkov telescopes will
provide thousands of simultaneously available baselines ranging from a few tens
of meters to over a kilometer, thus making imaging possible with unprecedented
angular resolution. Here we investigate the imaging capabilities of arrays such
as CTA or AGIS used as Stellar Intensity Interferometry receivers. The study
makes use of simulated data as could realistically be obtained from these
arrays. A Cauchy-Riemann based phase recovery allows the reconstruction of
images which can be compared to the pristine image for which the data were
simulated. This is first done for uniform disk stars with different radii and
corresponding to various exposure times, and we find that the uncertainty in
reconstructing radii is a few percent after a few hours of exposure time.
Finally, more complex images are considered, showing that imaging at the
sub-milli-arc-second scale is possible.Comment: 10 pages, 6 figures; presented at the SPIE conference "Optical and
Infrared Interferometry II", San Diego, CA, USA (June 2010
Impact of decitabine on immunohistochemistry expression of the putative tumor suppressor genes FHIT, WWOX, FUS1 and PTEN in clinical tumor samples.
BackgroundSince tumor suppressor gene function may be lost through hypermethylation, we assessed whether the demethylating agent decitabine could increase tumor suppressor gene expression clinically. For fragile histidine triad (FHIT), WW domain-containing oxidoreductase (WWOX), fused in sarcoma-1 (FUS1) and phosphatase and tensin homolog (PTEN), immunohistochemistry scores from pre- and post-decitabine tumor biopsies (25 patients) were correlated with methylation of the long interspersed nuclear element-1 (LINE-1) repetitive DNA element (as a surrogate for global DNA methylation) and with tumor regression.ResultsWith negative staining pre-decitabine (score = 0), the number of patients converting to positive staining post-decitabine was 1 of 1 for FHIT, 3 of 6 for WWOX, 2 of 3 for FUS1 and 1 of 10 for PTEN. In tumors with low pre-decitabine tumor suppressor gene scores (≤150), expression was higher post-treatment in 8 of 8 cases for FHIT (P = 0.014), 7 of 17 for WWOX (P = 0.0547), 7 of 12 for FUS1 (P = 0.0726), and 1 of 16 for PTEN (P = 0.2034). If FHIT, WWOX and FUS1 were considered together, median pre- versus post-decitabine scores were 60 versus 100 (P = 0.0002). Overall, tumor suppressor gene expression change did not correlate with LINE-1 demethylation, although tumors converting from negative to positive had a median decrease in LINE-1 methylation of 24%, compared to 6% in those not converting (P = 0.069). Five of 15 fully evaluable patients had reductions in tumor diameter (range 0.2% to 33.4%). Of these, three had simultaneous increases in three tumor suppressor genes (including the two patients with the greatest tumor regression) compared to 2 of 10 with tumor growth (P = 0.25).ConclusionsIn tumors with low tumor suppressor gene expression, decitabine may be associated with increased expression of the tumor suppressor genes FHIT, FUS1, and WWOX, but not PTEN
Fermions in Bosonic String Theories
We generalize the Jackiw-Rebbi-Hasenfratz-'t Hooft construction of fermions
from bosons to demonstrate the fermionic nature of certain bound states
involving SU(N) instantons in even spatial dimensions and SO(N) instantons in
spatial dimensions. We use this result to identify several fermionic
excitations in various perturbatively bosonic string theories. In some examples
we are able to identify these fermions as excitations in known conformal field
theories and independently confirm their fermionic nature. Examples of the
fermions we find include certain 3-string junctions in type 0B theory,
excitations of the 0-p system in type 0A theory, excitations of the stable
D-particle of type O theory, and a rich spectrum of fermions in the bosonic
string compactified on the SO(32) group lattice.Comment: 25 pages, 2 figs, harvmac ; v2, minor modifications, references adde
Exploring Double Field Theory
We present a flux formulation of Double Field Theory, in which geometric and
non-geometric fluxes are dynamical and field-dependent. Gauge consistency
imposes a set of quadratic constraints on the dynamical fluxes, which can be
solved by truly double configurations. The constraints are related to
generalized Bianchi Identities for (non-)geometric fluxes in the double space,
sourced by (exotic) branes. Following previous constructions, we then obtain
generalized connections, torsion and curvatures compatible with the consistency
conditions. The strong constraint-violating terms needed to make contact with
gauged supergravities containing duality orbits of non-geometric fluxes,
systematically arise in this formulation.Comment: To appear in JHE
MutY-Homolog (MYH) inhibition reduces pancreatic cancer cell growth and increases chemosensitivity
Patients with pancreatic ductal adenocarcinoma (PC) have a poor prognosis due to metastases and chemoresistance. PC is characterized by extensive fibrosis, which creates a hypoxic microenvironment, and leads to increased chemoresistance and intracellular oxidative stress. Thus, proteins that protect against oxidative stress are potential therapeutic targets for PC. A key protein that maintains genomic integrity against oxidative damage is MutY-Homolog (MYH). No prior studies have investigated the function of MYH in PC cells. Using siRNA, we showed that knockdown of MYH in PC cells 1) reduced PC cell proliferation and increased apoptosis; 2) further decreased PC cell growth in the presence of oxidative stress and chemotherapy agents (gemcitabine, paclitaxel and vincristine); 3) reduced PC cell metastatic potential; and 4) decreased PC tumor growth in a subcutaneous mouse model in vivo. The results from this study suggest MYH may be a novel therapeutic target for PC that could potentially improve patient outcome by reducing PC cell survival, increasing the efficacy of existing drugs and reducing metastatic spread
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The Billion Object Platform (BOP): a system to lower barriers to support big, streaming, spatio-temporal data sources
With funding from the Sloan Foundation and Harvard Dataverse, the Harvard Center for Geographic Analysis (CGA) has developed a big spatio-temporal data visualization platform called the Billion Object Platform or BOP . The goal of the project is to lower barriers for scholars who wish to access large, streaming, spatio-temporal datasets. Since once archived, streaming data gets big fast, and since most GIS systems don\u27t support interactive visualization of millions of objects, a new platform was needed. The BOP is loaded with the latest billion geo-tweets and is fed a real-time stream of about 1 million tweets per day. The CGA has been harvesting and archiving geo-tweets since 2012. As tweets flow into the BOP, they are enriched with sentiment and census information to support further analysis. Incoming and intermediate data is streamed/stored in Apache Kafka. The core of the BOP is Apache Solr, which supports fast search. Some significant enhancements were done to Solr (and contributed back) -- notably 2D heatmap faceting to support spatial visualization. The BOP fronts Solr with a RESTful web service, which provides a friendly, and secure API that is accessed from a browser-based client. The client developed, dynamically displays temporal and spatial distributions of results for result sets containing hundreds of millions of features. The system is open source and runs on commodity hardware. It is hosted on Massachusetts Open Cloud (MOC), an OpenStack environment. All components are deployed in Docker orchestrated by Kontena
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