5,218 research outputs found
The effect of weak lensing on distance estimates from supernovae
Using a sample of 608 Type Ia supernovae from the SDSS-II and BOSS surveys, combined with a sample of
foreground galaxies from SDSS-II, we estimate the weak lensing convergence for each supernova line of sight.
We find that the correlation between this measurement and the Hubble residuals is consistent with the prediction
from lensing (at a significance of 1.7?). Strong correlations are also found between the residuals and supernova
nuisance parameters after a linear correction is applied. When these other correlations are taken into account, the
lensing signal is detected at 1.4?. We show, for the first time, that distance estimates from supernovae can be
improved when lensing is incorporated, by including a new parameter in the SALT2 methodology for determining
distance moduli. The recovered value of the new parameter is consistent with the lensing prediction. Using cosmic
microwave background data from WMAP7, H0 data from Hubble Space Telescope and Sloan Digital Sky Survey
(SDSS) Baryon acoustic oscillations measurements, we find the best-fit value of the new lensing parameter and
show that the central values and uncertainties on ?m and w are unaffected. The lensing of supernovae, while only
seen at marginal significance in this low-redshift sample, will be of vital importance for the next generation of
surveys, such as DES and LSST, which will be systematics-dominated.Web of Scienc
Modeling a Grid-Connected PV/Battery Microgrid System with MPPT Controller
This paper focuses on performance analyzing and dynamic modeling of the
current grid-tied fixed array 6.84kW solar photovoltaic system located at
Florida Atlantic University (FAU). A battery energy storage system is designed
and applied to improve the systems stability and reliability. An overview of
the entire system and its PV module are presented. In sequel, the corresponding
I-V and P-V curves are obtained using MATLAB-Simulink package. Actual data was
collected and utilized for the modeling and simulation of the system. In
addition, a grid- connected PV/Battery system with Maximum Power Point Tracking
(MPPT) controller is modeled to analyze the system performance that has been
evaluated under two different test conditions: (1) PV power production is
higher than the load demand (2) PV generated power is less than required load.
A battery system has also been sized to provide smoothing services to this
array. The simulation results show the effective of the proposed method. This
system can be implemented in developing countries with similar weather
conditions to Florida.Comment: 6 pages, 14 figures, PVSC 201
Architecture of a Post Physical Universe
As architects we are fundamentally forced to make arguments within the physical realm. However since mid 1990’s the world has become more and more reliant upon the digital. Now in 2017 it is the way we voice public opinion, shop, visit with our friends and much more. This digital space has taken over, and while humanity would more than survive without this modern technology, it continues design our world around it. This architecture project glimpses into the future of how we as architects are continually dealing with this new infrastructural space. While many projects have played architecture as the victim, the intent of this project is not to look down and say “this will kill that.” Instead this project acknowledges current modes architectural technologies in this realm and pushes further to start a dialogue on how we as architects can and will be involved in this digital space
Investigating the Role of TORC1 and the Transcription Factor Sfp1p in the Regulation of HMO1 Gene in Saccharomyces cerevisiae
HMGB proteins are eukaryotic, chromatin-associated proteins that play roles in both DNA dynamics and transcription regulation. Hmo1p is an HMGB protein in Saccharomyces cerevisiae that behaves somewhat like a hybrid between mammalian HMGB proteins and the metazoan linker histone H1. mTORC1, a protein complex containing the Tor1p kinase and a major regulator of cellular growth, is inhibited by both rapamycin and stress. It has also been shown to not only associate with Hmo1p at various gene promoters, but also regulate the HMO1 gene itself through direct binding. In this study, the Hmo1p-mTORC1 relationship was further investigated through two questions: 1) Does the transcription factor Sfp1p play a role in relaying mTORC1’s signal to the HMO1 promoter, and 2) Is the reduction in HMO1 transcripts during stress dependent on mTORC1? Gene expression analyses revealed that Sfp1p is not required for normal HMO1 transcription; however, it does appear to play a role in transmitting the mTORC1 stress signal to the promoter, as transcripts are only significantly decreased during stress when Sfp1p is present. Survival tests revealed that Sfp1p might be hindering the cell’s ability to repair DNA double-strand breaks, as there is a slight increase in cell survival during double-strand break-induction when Sfp1p is knocked-out; however, there is some uncertainty as to whether this is Hmo1p-related. Chromatin Immunoprecipitation techniques were then used to demonstrate that RNA polymerase II is evicted from the HMO1 gene over the course of one hour during stress when Tor1p is knocked-out. This same phenomenon had previously been shown in wild-type cells; however, HMO1 transcripts are only attenuated in wild-type cells, and not when Tor1p is knocked-out. This suggests that mTORC1 is responsible for the reduction of HMO1 mRNA during stress. We propose the possibility that mTORC1 is participating in active mRNA degradation at the HMO1 gene, and that transcription-inhibition techniques can be utilized to confirm this
XFlow: An algorithm for extracting ion chromatograms
Abstract: Mass spectrometry is a fundamental tool for modern proteomics. The increasing availability of mass spectrometry data paired with the increasing sensitivity and fidelity of the instruments necessitates new and more potent analytical methods. To that end, we have created and present XFlow, a feature detection algorithm for extracting ion chromatograms from MS1 LC-MS data. XFlow is a parameter-free procedurally agnostic feature detection algorithm that utilizes the latent properties of ion chromatograms to resolve them from the surrounding noise present in MS1 data. XFlow is designed to function on either profile or centroided data across different resolutions and instruments. This broad applicability lends XFlow strong utility as a one-size-fits-all method for MS1 analysis or target acquisition for MS2. XFlow is written in Java and packaged with JS-MS, an open-source mass spectrometry analysis toolkit
The evolving relation between star-formation rate and stellar mass in the VIDEO Survey since
We investigate the star-formation rate (SFR) and stellar mass ()
relation of a star-forming (SF) galaxy sample in the XMM-LSS field to using the near-infrared data from the VISTA Deep Extragalactic
Observations (VIDEO) survey. Combining VIDEO with broad-band photometry, we use
the SED fitting algorithm CIGALE to derive SFRs and and have adapted it
to account for the full photometric redshift PDF uncertainty. Applying a SF
selection using the D4000 index, we find evidence for strong evolution in the
normalisation of the SFR- relation out to and a roughly constant
slope of (SFR ) to . We
find this increases close to unity toward . Alternatively, if we
apply a colour selection, we find a distinct turnover in the SFR- relation
between at the high mass end, and suggest that this
is due to an increased contamination from passive galaxies. We find evolution
of the specific SFR at 10.5, out to
with an observed flattening beyond 2 with increased
stellar mass. Comparing to a range of simulations we find the analytical
scaling relation approaches, that invoke an equilibrium model, a good fit to
our data, suggesting that a continual smooth accretion regulated by continual
outflows may be a key driver in the overall growth of SFGs.Comment: 19 pages, 18 figures, accepted for publication in MNRA
NOUS: Construction and Querying of Dynamic Knowledge Graphs
The ability to construct domain specific knowledge graphs (KG) and perform
question-answering or hypothesis generation is a transformative capability.
Despite their value, automated construction of knowledge graphs remains an
expensive technical challenge that is beyond the reach for most enterprises and
academic institutions. We propose an end-to-end framework for developing custom
knowledge graph driven analytics for arbitrary application domains. The
uniqueness of our system lies A) in its combination of curated KGs along with
knowledge extracted from unstructured text, B) support for advanced trending
and explanatory questions on a dynamic KG, and C) the ability to answer queries
where the answer is embedded across multiple data sources.Comment: Codebase: https://github.com/streaming-graphs/NOU
KSZ tomography and the bispectrum
Several statistics have been proposed for measuring the kSZ effect by
combining the small-scale CMB with galaxy surveys. We review five such
statistics, and show that they are all mathematically equivalent to the optimal
bispectrum estimator of type . Reinterpreting these kSZ
statistics as special cases of bispectrum estimation makes many aspects
transparent, for example optimally weighting the estimator, or incorporating
photometric redshift errors. We analyze the information content of the
bispectrum and show that there are two observables: the small-scale
galaxy-electron power spectrum , and the large-scale
galaxy-velocity power spectrum . The cosmological constraining power
of the kSZ arises from its sensitivity to fluctuations on large length scales,
where its effective noise level can be much better than galaxy surveys.Comment: 39 page
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