5,964 research outputs found
Molecular Gas during the Post-Starburst Phase: Low Gas Fractions in Green Valley Seyfert Post-Starburst Galaxies
Post-starbursts (PSBs) are candidate for rapidly transitioning from
star-bursting to quiescent galaxies. We study the molecular gas evolution of
PSBs at z ~ 0.03 - 0.2. We undertook new CO (2-1) observations of 22 Seyfert
PSBs candidates using the ARO Submillimeter Telescope. This sample complements
previous samples of PSBs by including green valley PSBs with Seyfert-like
emission, allowing us to analyze for the first time the molecular gas
properties of 116 PSBs with a variety of AGN properties. The distribution of
molecular gas to stellar mass fractions in PSBs is significantly different than
normal star-forming galaxies in the COLD GASS survey. The combined samples of
PSBs with Seyfert-like emission line ratios have a gas fraction distribution
which is even more significantly different and is broader (~ 0.03-0.3). Most of
them have lower gas fractions than normal star-forming galaxies. We find a
highly significant correlation between the WISE 12 micron to 4.6 micron flux
ratios and molecular gas fractions in both PSBs and normal galaxies. We detect
molecular gas in 27% of our Seyfert PSBs. Taking into account the upper limits,
the mean and the dispersion of the distribution of the gas fraction in our
Seyfert PSB sample are much smaller (mean = 0.025, std dev. = 0.018) than
previous samples of Seyfert PSBs or PSBs in general (mean ~ 0.1 - 0.2, std dev.
~ 0.1 - 0.2).Comment: 17 pages, 12 figures accepted in MNRA
Proof of Luck: an Efficient Blockchain Consensus Protocol
In the paper, we present designs for multiple blockchain consensus primitives
and a novel blockchain system, all based on the use of trusted execution
environments (TEEs), such as Intel SGX-enabled CPUs. First, we show how using
TEEs for existing proof of work schemes can make mining equitably distributed
by preventing the use of ASICs. Next, we extend the design with proof of time
and proof of ownership consensus primitives to make mining energy- and
time-efficient. Further improving on these designs, we present a blockchain
using a proof of luck consensus protocol. Our proof of luck blockchain uses a
TEE platform's random number generation to choose a consensus leader, which
offers low-latency transaction validation, deterministic confirmation time,
negligible energy consumption, and equitably distributed mining. Lastly, we
discuss a potential protection against up to a constant number of compromised
TEEs.Comment: SysTEX '16, December 12-16, 2016, Trento, Ital
Divergence at low bias and down-mixing of the current noise in a diffusive superconductor-normal metal-superconductor junction
We present current noise measurements in a long diffusive
superconductor-normal-metal-superconductor junction in the low voltage regime,
in which transport can be partially described in terms of coherent multiple
Andreev reflections. We show that, when decreasing voltage, the current noise
exhibits a strong divergence together with a broad peak. We ascribe this peak
to the mixing between the ac- Josephson current and the noise of the junction
itself. We show that the junction noise corresponds to the thermal noise of a
nonlinear resistor 4kBT=R with R V = I V and no adjustable parameters
Is the magnetic field in the heliosheath laminar or a turbulent bath of bubbles?
All the current global models of the heliosphere are based on the assumption
that the magnetic field in the heliosheath, in the region close to the
heliopause is laminar. We argue that in that region the heliospheric magnetic
field is not laminar but instead consists of magnetic bubbles. Recently, we
proposed that the annihilation of the "sectored" magnetic field within the
heliosheath as it is compressed on its approach to the heliopause produces the
anomalous cosmic rays and also energetic electrons. As a product of the
annihilation of the sectored magnetic field, densely-packed magnetic
islands/bubbles are produced. These magnetic islands/bubbles will be convected
with the ambient flows as the sector region is carried to higher latitudes
filling the heliosheath. We further argue that the magnetic islands/bubbles
will develop upstream within the heliosheath. As a result, the magnetic field
in the heliosheath sector region will be disordered well upstream of the
heliopause. We present a 3D MHD simulation with very high numerical resolution
that captures the north-south boundaries of the sector region. We show that due
to the high pressure of the interstellar magnetic field a north-south asymmetry
develops such that the disordered sectored region fills a large portion of the
northern part of the heliosphere with a smaller extension in the southern
hemisphere. We suggest that this scenario is supported by the following changes
that occur around 2008 and from 2009.16 onward: a) the sudden decrease in the
intensity of low energy electrons detected by Voyager 2; b) a sharp reduction
in the intensity of fluctuations of the radial flow; and c) the dramatic
differences in intensity trends between GCRs at V1 and 2. We argue that these
observations are a consequence of V2 leaving the sector region of disordered
field during these periods and crossing into a region of unipolar laminar
field.Comment: 36 pages, 15 figures, submitted to Ap
Prevalence of \u3ci\u3eEimeria\u3c/i\u3e (Apicomplexa: Eimeriidae) in Reintroduced Gunnison\u27s Prairie Dogs (\u3ci\u3eCynomys gunnisoni\u3c/i\u3e)
Fecal samples from 54 Gunnison’s prairie dogs (Cynomys gunnisoni) from Albuquerque, NM were analyzed for the presence of coccidia and all were positive. They were then relocated to an abandoned prairie dog town on the Sevilleta Long Term Ecological Research (LTER) site. Six Eimeria species, E. callospermophili, E. cynomysis, E. pseudospermophili (new host record), E. spermophili, E. ludoviciani and E. vilasi (new host record) were found in Albuquerque animals, but only two species, E. callospermophili and E. vilasi were present in relocated hosts. A significant (P \u3c 0.05) reduction was seen in the prevalence of E. vilasi (72% vs. 13%) and in the prevalence of infections (P \u3c 0.05) with two or more Eimeria species (39% vs. 4%) in pre- and postrelocation animals. To assess the impact of the introduction of C. gunnisoni on the resident rodent population, feces were collected from 6 species of rodents. Five Eimeria species, E. arizonensis (Reithrodontomys), E. chobotari (Dipodomys, Perognathus), E. liomysis (Dipodomys), E. mohavensis (Dipodomys) and E. reedi (Perognathus) were found. We found no evidence of coccidia transfer among introduced and resident rodent species
Acute Liver Failure Secondary to Hemophagocytic Lymphohistiocytosis during Pregnancy.
Hemophagocytic lymphohistiocytosis (HLH) is a syndrome of excessive immune activation that mimics and occurs with other systemic diseases. A 35-year-old female presented with signs of viral illness at 13 weeks of pregnancy and progressed to acute liver failure (ALF). We discuss the diagnosis of HLH and Kikuchi-Fujimoto (KF) lymphadenitis in the context of pregnancy and ALF. HLH may respond to comorbid disease-specific therapy, and more toxic treatment can be avoided
Mirror symmetry breaking as a problem in dynamical critical phenomena
The critical properties of the Frank model of spontaneous chiral synthesis
are discussed by applying results from the field theoretic renormalization
group (RG). The long time and long wavelength features of this microscopic
reaction scheme belong to the same universality class as multi-colored directed
percolation processes. Thus, the following RG fixed points (FP) govern the
critical dynamics of the Frank model for d<4: one unstable FP that corresponds
to complete decoupling between the two enantiomers, a saddle-point that
corresponds to symmetric interspecies coupling, and two stable FPs that
individually correspond to unidirectional couplings between the two chiral
molecules. These latter two FPs are associated with the breakdown of mirror or
chiral symmetry. In this simplified model of molecular synthesis, homochirality
is a natural consequence of the intrinsic reaction noise in the critical
regime, which corresponds to extremely dilute chemical systems.Comment: 9 pages, 3 figure
Answers that Have Integrity
[EN] Answers to queries in possibly inconsistent databases may
not have integrity. We formalize ‘has integrity’ on the basis of a definition
of ‘causes’. A cause of an answer is a minimal excerpt of the database
that explains why the answer has been given. An answer has integrity if
one of its causes does not overlap with any cause of integrity violation.Supported by FEDER and the Spanish grants TIN2009-14460-C03, TIN2010-17139.Decker, H. (2011). Answers that Have Integrity. Lecture Notes in Computer Science. 6834:54-72. https://doi.org/10.1007/978-3-642-23441-5S5472683
Space shuttle abort separation pressure investigation. Volume 2, Part B: Orbiter data at Mach 5
For abstract, see
- …