1,021 research outputs found
Mono Lake or Laschamp geomagnetic event recorded from lava flows in Amsterdam Island (southeastern Indian Ocean)
We report a survey carried out on basalt flows from Amsterdam Island in order
to check the presence of intermediate directions interpreted to belong to a
geomagnetic field excursion within the Brunhes epoch, completing this
paleomagnetic record with paleointensity determinations and radiometric dating.
The directional results corroborate the findings by Watkins and Nougier (1973)
: normal polarity is found for two units and an intermediate direction, with
associated VGPs close to the equator, for the other two units. A notable result
is that these volcanic rocks are well suited for absolute paleointensity
determinations. Fifty percent of the samples yields reliable intensity values
with high quality factors. An original element of this study is that we made
use of the PTRM-tail test of Shcherbakova et al. (2000) to help in the
interpretation of the paleointensity measurements. Doing thus, only the high
temperature intervals, beyond 400 degres C, were retained to obtain the most
reliable estimate of the strength of the ancient magnetic field. The normal
units yield Virtual Dipole Moments (VDM) of 6.2 and 7.7 10e22 Am2 and the
excursional units yield values of 3.7 and 3.4 10e22 Am2. These results are
quite consistent with the other Thellier determinations from Brunhes excursion
records, all characterized by a decrease of the VDM as VGP latitude decreases.
40Ar/39Ar isotopic age determinations provide an estimate of 26+-15 Kyr and
18+-9 Kyr for the transitional lava flows, which could correspond to the Mono
Lake excursion. However, the large error bars associated with these ages do not
exclude the hypothesis that this event is the Laschamp
Optimized Compilation of Aggregated Instructions for Realistic Quantum Computers
Recent developments in engineering and algorithms have made real-world
applications in quantum computing possible in the near future. Existing quantum
programming languages and compilers use a quantum assembly language composed of
1- and 2-qubit (quantum bit) gates. Quantum compiler frameworks translate this
quantum assembly to electric signals (called control pulses) that implement the
specified computation on specific physical devices. However, there is a
mismatch between the operations defined by the 1- and 2-qubit logical ISA and
their underlying physical implementation, so the current practice of directly
translating logical instructions into control pulses results in inefficient,
high-latency programs. To address this inefficiency, we propose a universal
quantum compilation methodology that aggregates multiple logical operations
into larger units that manipulate up to 10 qubits at a time. Our methodology
then optimizes these aggregates by (1) finding commutative intermediate
operations that result in more efficient schedules and (2) creating custom
control pulses optimized for the aggregate (instead of individual 1- and
2-qubit operations). Compared to the standard gate-based compilation, the
proposed approach realizes a deeper vertical integration of high-level quantum
software and low-level, physical quantum hardware. We evaluate our approach on
important near-term quantum applications on simulations of superconducting
quantum architectures. Our proposed approach provides a mean speedup of
, with a maximum of . Because latency directly affects the
feasibility of quantum computation, our results not only improve performance
but also have the potential to enable quantum computation sooner than otherwise
possible.Comment: 13 pages, to apper in ASPLO
Low Cost Delivery of Proteins Bioencapsulated in Plant Cells to Human Non-Immune or Immune Modulatory Cells
Targeted oral delivery of GFP fused with a GM1 receptor binding protein (CTB) or human cell penetrating peptide (PTD) or dendritic cell peptide (DCpep) was investigated. Presence of GFP+ intact plant cells between villi of ileum confirm their protection in the digestive system from acids/enzymes. Efficient delivery of GFP to gut-epithelial cells by PTD or CTB and to M cells by all these fusion tags confirm uptake of GFP in the small intestine. PTD fusion delivered GFP more efficiently to most tissues or organs than other two tags. GFP was efficiently delivered to the liver by all fusion tags, likely through the gut-liver axis. In confocal imaging studies of human cell lines using purified GFP fused with different tags, GFP signal of DCpep-GFP was only detected within dendritic cells. PTD-GFP was only detected within kidney or pancreatic cells but not in immune modulatory cells (macrophages, dendritic, T, B, or mast cells). In contrast, CTB-GFP was detected in all tested cell types, confirming ubiquitous presence of GM1 receptors. Such low-cost oral delivery of protein drugs to sera, immune system or non-immune cells should dramatically lower their cost by elimination of prohibitively expensive fermentation, protein purification cold storage/transportation and increase patient compliance
Association between celiac sprue and cryopyrin associated autoinflammatory disorders: a case report
Cryopyrin-associated diseases may be characterized by rashes, fever, and sensorineural deafness, while celiac disease may present with symptoms of malabsorption and fatigue. Arthritis is seen in both conditions. We report a young child with histologically diagnosed celiac disease and a cryopyrinopathy
Dark matter and structure formation a review
This paper provides a review of the variants of dark matter which are thought
to be fundamental components of the universe and their role in origin and
evolution of structures and some new original results concerning improvements
to the spherical collapse model. In particular, I show how the spherical
collapse model is modified when we take into account dynamical friction and
tidal torques
The role of cold gas and environment on the stellar mass - metallicity relation of nearby galaxies
We investigate the relationship between stellar mass, metallicity and gas
content for a magnitude- and volume-limited sample of 260 nearby late-type
galaxies in different environments, from isolated galaxies to Virgo cluster
members. We derive oxygen abundance estimates using new integrated, drift-scan
optical spectroscopy and the base metallicity calibrations of Kewley & Ellison
(2008). Combining these measurements with ultraviolet to near-infrared
photometry and HI 21 cm line observations, we examine the relations between
stellar mass, metallicity, gas mass fraction and star formation rate. We find
that, at fixed stellar mass, galaxies with lower gas fractions typically also
possess higher oxygen abundances. We also observe a relationship between gas
fraction and metal content, whereby gas-poor galaxies are typically more
metal-rich, and demonstrate that the removal of gas from the outskirts of
spirals increases the observed average metallicity by approximately 0.1 dex.
Although some cluster galaxies are gas-deficient objects, statistically the
stellar-mass metallicity relation is nearly invariant to the environment, in
agreement with recent studies. These results indicate that internal
evolutionary processes, rather than environmental effects, play a key role in
shaping the stellar mass-metallicity relation. In addition, we present
metallicity estimates based on observations of 478 nearby galaxies.Comment: Accepted for publication in A&A. 28 pages, including 10 figures and 3
table
Identified baryon and meson distributions at large transverse momenta from Au+Au collisions at GeV
Transverse momentum spectra of , and up to 12 GeV/c
at mid-rapidity in centrality selected Au+Au collisions at GeV are presented. In central Au+Au collisions, both and
show significant suppression with respect to binary scaling at
4 GeV/c. Protons and anti-protons are less suppressed than
, in the range 1.5 6 GeV/c. The and
ratios show at most a weak dependence and no significant
centrality dependence. The ratios in central Au+Au collisions approach
the values in p+p and d+Au collisions at 5 GeV/c. The results at high
indicate that the partonic sources of , and have
similar energy loss when traversing the nuclear medium.Comment: 6 pages, 4 figure
Longitudinal double-spin asymmetry and cross section for inclusive jet production in polarized proton collisions at sqrt(s) = 200 GeV
We report a measurement of the longitudinal double-spin asymmetry A_LL and
the differential cross section for inclusive midrapidity jet production in
polarized proton collisions at sqrt(s)=200 GeV. The cross section data cover
transverse momenta 5 < pT < 50 GeV/c and agree with next-to-leading order
perturbative QCD evaluations. The A_LL data cover 5 < pT < 17 GeV/c and
disfavor at 98% C.L. maximal positive gluon polarization in the polarized
nucleon.Comment: 6 pages, 3 figures. Minor changes from review process in Phys. Rev.
Lett. Plain text tables of data in STAR publications may be found at
http://www.star.bnl.gov/central/publications
Longitudinal double-spin asymmetry for inclusive jet production in p+p collisions at sqrt(s)=200 GeV
We report a new STAR measurement of the longitudinal double-spin asymmetry
A_LL for inclusive jet production at mid-rapidity in polarized p+p collisions
at a center-of-mass energy of sqrt(s) = 200 GeV. The data, which cover jet
transverse momenta 5 < p_T < 30 GeV/c, are substantially more precise than
previous measurements. They provide significant new constraints on the gluon
spin contribution to the nucleon spin through the comparison to predictions
derived from one global fit of polarized deep-inelastic scattering
measurements.Comment: 7 pages, 4 figures + 1 tabl
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