The ALMaQUEST (ALMA-MaNGA QUEnching and STar formation) survey is a program with spatially resolved 12CO(1−0) measurements obtained with the Atacama Large Millimeter Array (ALMA) for 46 galaxies ...selected from the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) DR15 optical integral-field spectroscopic survey. The aim of the ALMaQUEST survey is to investigate the dependence of star formation activity on the cold molecular gas content at kiloparsec scales in nearby galaxies. The sample consists of galaxies spanning a wide range in specific star formation rate (sSFR), including starburst (SB), main-sequence (MS), and green valley (GV) galaxies. In this paper, we present the sample selection and characteristics of the ALMA observations and showcase some of the key results enabled by the combination of spatially matched stellar populations and gas measurements. Considering the global (aperture-matched) stellar mass, molecular gas mass, and star formation rate of the sample, we find that the sSFR depends on both the star formation efficiency (SFE) and the molecular gas fraction ( ), although the correlation with the latter is slightly weaker. Furthermore, the dependence of sSFR on the molecular gas content (SFE or ) is stronger than that on either the atomic gas fraction or the molecular-to-atomic gas fraction, albeit with the small Hi sample size. On kiloparsec scales, the variations in both SFE and within individual galaxies can be as large as 1-2 dex, thereby demonstrating that the availability of spatially resolved observations is essential to understand the details of both star formation and quenching processes.
The underlying pathology of arsenic-related cardiovascular disease (CVD) is unknown. Few studies have evaluated pathways through thrombosis and inflammation for arsenic-related CVD, especially at ...low-moderate arsenic exposure levels (<100 μg/L in drinking water). We evaluated the association of chronic low-moderate arsenic exposure, measured as the sum of inorganic and methylated arsenic species in urine (ΣAs), with plasma biomarkers of thrombosis and inflammation in American Indian adults (45-74 years) in the Strong Heart Study. We evaluated the cross-sectional and longitudinal associations between baseline ΣAs with fibrinogen at three visits (baseline, 1989-91; Visit 2, 1993-95, Visit 3, 1998-99) using mixed models and the associations between baseline ΣAs and Visit 2 plasminogen activator inhibitor-1 (PAI-1) and high sensitivity C-reactive protein (hsCRP) using linear regression. Median (interquartile range) concentrations of baseline ΣAs and fibrinogen, and Visit 2 hsCRP and PAI-1 were 8.4 (5.1, 14.3) μg/g creatinine, 346 (304, 393) mg/dL, 44 (30, 67) mg/L, and 3.8 (2.0, 7.0) ng/mL, respectively. Comparing the difference between the 75th and the 25th percentile of ΣAs (14.3 vs. 5.1 μg/g creatinine), ΣAs was positively associated with baseline fibrinogen among those with diabetes (adjusted geometric mean ratio (GMR): 1.05, 95% CI: 1.02, 1.07) not associated among those without diabetes (GMR: 1.01, 95% CI: 0.99, 1.02) (p-interaction for diabetes = 0.014), inversely associated with PAI-1 (GMR: 0.94, 95% CI: 0.90, 0.99), and not associated with hsCRP (GMR: 1.00, 95% CI: 0.93, 1.08). We found no evidence for an association between baseline ΣAs and annual change in fibrinogen over follow-up (p-interaction = 0.28 and 0.12 for diabetes and non-diabetes, respectively). Low-moderate arsenic exposure was positively associated with baseline fibrinogen in participants with diabetes and unexpectedly inversely associated with PAI-1. Further research should evaluate the role of prothrombotic factors in arsenic-related cardiovascular disease.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Mars 2020 Mission Overview Farley, Kenneth A.; Williford, Kenneth H.; Stack, Kathryn M. ...
Space science reviews,
12/2020, Letnik:
216, Številka:
8
Journal Article
Recenzirano
The Mars 2020 mission will seek the signs of ancient life on Mars and will identify, prepare, document, and cache a set of samples for possible return to Earth by a follow-on mission. Mars 2020 and ...its
Perseverance
rover thus link and further two long-held goals in planetary science: a deep search for evidence of life in a habitable extraterrestrial environment, and the return of martian samples to Earth for analysis in terrestrial laboratories.
The Mars 2020 spacecraft is based on the design of the highly successful Mars Science Laboratory and its
Curiosity
rover, but outfitted with a sophisticated suite of new science instruments. Ground-penetrating radar will illuminate geologic structures in the shallow subsurface, while a multi-faceted weather station will document martian environmental conditions. Several instruments can be used individually or in tandem to map the color, texture, chemistry, and mineralogy of rocks and regolith at the meter scale and at the submillimeter scale. The science instruments will be used to interpret the geology of the landing site, to identify habitable paleoenvironments, to seek ancient textural, elemental, mineralogical and organic biosignatures, and to locate and characterize the most promising samples for Earth return. Once selected, ∼35 samples of rock and regolith weighing about 15 grams each will be drilled directly into ultraclean and sterile sample tubes.
Perseverance
will also collect blank sample tubes to monitor the evolving rover contamination environment.
In addition to its scientific instruments,
Perseverance
hosts technology demonstrations designed to facilitate future Mars exploration. These include a device to generate oxygen gas by electrolytic decomposition of atmospheric carbon dioxide, and a small helicopter to assess performance of a rotorcraft in the thin martian atmosphere.
Mars 2020 entry, descent, and landing (EDL) will use the same approach that successfully delivered
Curiosity
to the martian surface, but with several new features that enable the spacecraft to land at previously inaccessible landing sites. A suite of cameras and a microphone will for the first time capture the sights and sounds of EDL.
Mars 2020’s landing site was chosen to maximize scientific return of the mission for astrobiology and sample return. Several billion years ago Jezero crater held a 40 km diameter, few hundred-meter-deep lake, with both an inflow and an outflow channel. A prominent delta, fine-grained lacustrine sediments, and carbonate-bearing rocks offer attractive targets for habitability and for biosignature preservation potential. In addition, a possible volcanic unit in the crater and impact megabreccia in the crater rim, along with fluvially-deposited clasts derived from the large and lithologically diverse headwaters terrain, contribute substantially to the science value of the sample cache for investigations of the history of Mars and the Solar System. Even greater diversity, including very ancient aqueously altered rocks, is accessible in a notional rover traverse that ascends out of Jezero crater and explores the surrounding Nili Planum.
Mars 2020 is conceived as the first element of a multi-mission Mars Sample Return campaign. After Mars 2020 has cached the samples, a follow-on mission consisting of a fetch rover and a rocket could retrieve and package them, and then launch the package into orbit. A third mission could capture the orbiting package and return it to Earth. To facilitate the sample handoff,
Perseverance
could deposit its collection of filled sample tubes in one or more locations, called depots, on the planet’s surface. Alternatively, if
Perseverance
remains functional, it could carry some or all the samples directly to the retrieval spacecraft.
The Mars 2020 mission and its
Perseverance
rover launched from the Eastern Range at Cape Canaveral Air Force Station, Florida, on July 30, 2020. Landing at Jezero Crater will occur on Feb 18, 2021 at about 12:30 PM Pacific Time.
BACKGROUND
The Sarcopenia Definitions and Outcomes Consortium (SDOC) sought to identify cut points for muscle strength and body composition measures derived from dual‐energy x‐ray absorptiometry ...(DXA) that discriminate older adults with slow walking speed. This article presents the core analyses used to guide the SDOC position statements.
DESIGN
Cross‐sectional data analyses of pooled data.
SETTING
University‐based research assessment centers.
PARTICIPANTS
Community‐dwelling men (n = 13,652) and women: (n = 5,115) with information on lean mass by DXA, grip strength (GR), and walking speed.
MEASUREMENTS
Thirty‐five candidate sarcopenia variables were entered into sex‐stratified classification and regression tree (CART) models to agnostically choose variables and cut points that discriminate slow walkers (<0.80 m/s). Models with alternative walking speed outcomes were also evaluated (<0.60 and <1.0 m/s and walking speed treated continuously).
RESULTS
CART models identified GR/body mass index (GRBMI) and GR/total body fat (GRTBF) as the primary discriminating variables for slowness in men and women, respectively. Men with GRBMI of 1.05 kg/kg/m2 or less were approximately four times more likely to be slow walkers than those with GRBMI of greater than 1.05 kg/kg/m2. Women with GRTBF of less than 0.65 kg/kg were twice as likely to be slow walkers than women with GRTBF of 0.65 kg/kg or greater. Models with alternative walking speed outcomes selected only functions of GR as primary discriminators of slowness in both men and women. DXA‐derived lean mass measures did not consistently discriminate slow walkers.
CONCLUSION
GR with and without adjustments for body size and composition consistently discriminated older adults with slowness. CART models did not select DXA‐based lean mass as a primary discriminator of slowness. These results were presented to an SDOC Consensus Panel, who used them and other information to develop the SDOC Position Statements. J Am Geriatr Soc 68:1419‐1428, 2020.
See related editorial by Cesari et al in this issue.
Realizing the potential of quantum computing requires sufficiently low logical error rates.sup.1. Many applications call for error rates as low as 10.sup.-15 (refs. .sup.2-9), but state-of-the-art ...quantum platforms typically have physical error rates near 10.sup.-3 (refs. .sup.10-14). Quantum error correction.sup.15-17 promises to bridge this divide by distributing quantum logical information across many physical qubits in such a way that errors can be detected and corrected. Errors on the encoded logical qubit state can be exponentially suppressed as the number of physical qubits grows, provided that the physical error rates are below a certain threshold and stable over the course of a computation. Here we implement one-dimensional repetition codes embedded in a two-dimensional grid of superconducting qubits that demonstrate exponential suppression of bit-flip or phase-flip errors, reducing logical error per round more than 100-fold when increasing the number of qubits from 5 to 21. Crucially, this error suppression is stable over 50 rounds of error correction. We also introduce a method for analysing error correlations with high precision, allowing us to characterize error locality while performing quantum error correction. Finally, we perform error detection with a small logical qubit using the 2D surface code on the same device.sup.18,19 and show that the results from both one- and two-dimensional codes agree with numerical simulations that use a simple depolarizing error model. These experimental demonstrations provide a foundation for building a scalable fault-tolerant quantum computer with superconducting qubits.
Abstract
Ensembl Genomes (http://www.ensemblgenomes.org) is an integrating resource for genome-scale data from non-vertebrate species, complementing the resources for vertebrate genomics developed in ...the Ensembl project (http://www.ensembl.org). Together, the two resources provide a consistent set of programmatic and interactive interfaces to a rich range of data including genome sequence, gene models, transcript sequence, genetic variation, and comparative analysis. This paper provides an update to the previous publications about the resource, with a focus on recent developments and expansions. These include the incorporation of almost 20 000 additional genome sequences and over 35 000 tracks of RNA-Seq data, which have been aligned to genomic sequence and made available for visualization. Other advances since 2015 include the release of the database in Resource Description Framework (RDF) format, a large increase in community-derived curation, a new high-performance protein sequence search, additional cross-references, improved annotation of non-protein-coding genes, and the launch of pre-release and archival sites. Collectively, these changes are part of a continuing response to the increasing quantity of publicly-available genome-scale data, and the consequent need to archive, integrate, annotate and disseminate these using automated, scalable methods.
Quantum many-body systems display rich phase structure in their low-temperature equilibrium states
. However, much of nature is not in thermal equilibrium. Remarkably, it was recently predicted that ...out-of-equilibrium systems can exhibit novel dynamical phases
that may otherwise be forbidden by equilibrium thermodynamics, a paradigmatic example being the discrete time crystal (DTC)
. Concretely, dynamical phases can be defined in periodically driven many-body-localized (MBL) systems via the concept of eigenstate order
. In eigenstate-ordered MBL phases, the entire many-body spectrum exhibits quantum correlations and long-range order, with characteristic signatures in late-time dynamics from all initial states. It is, however, challenging to experimentally distinguish such stable phases from transient phenomena, or from regimes in which the dynamics of a few select states can mask typical behaviour. Here we implement tunable controlled-phase (CPHASE) gates on an array of superconducting qubits to experimentally observe an MBL-DTC and demonstrate its characteristic spatiotemporal response for generic initial states
. Our work employs a time-reversal protocol to quantify the impact of external decoherence, and leverages quantum typicality to circumvent the exponential cost of densely sampling the eigenspectrum. Furthermore, we locate the phase transition out of the DTC with an experimental finite-size analysis. These results establish a scalable approach to studying non-equilibrium phases of matter on quantum processors.
Isoprenoids are used in many commercial applications and much work has gone into engineering microbial hosts for their production. Isoprenoids are produced either from acetyl-CoA via the mevalonate ...pathway or from pyruvate and glyceraldehyde 3-phosphate via the 1-deoxy-D-xylulose 5-phosphate (DXP) pathway. Saccharomyces cerevisiae exclusively utilizes the mevalonate pathway to synthesize native isoprenoids and in fact the alternative DXP pathway has never been found or successfully reconstructed in the eukaryotic cytosol. There are, however, several advantages to isoprenoid synthesis via the DXP pathway, such as a higher theoretical yield, and it has long been a goal to transplant the pathway into yeast. In this work, we investigate and address barriers to DXP pathway functionality in S. cerevisiae using a combination of synthetic biology, biochemistry and metabolomics. We report, for the first time, functional expression of the DXP pathway in S. cerevisiae. Under low aeration conditions, an engineered strain relying solely on the DXP pathway for isoprenoid biosynthesis achieved an endpoint biomass 80% of that of the same strain using the mevalonate pathway.
•A heterologous DXP pathway has been functionally expressed in the yeast cytosol.•Identification of two functional pathway enzymes, IspG and IspH, was key.•Further optimization enabled growth in the absence of the mevalonate pathway.
Information scrambling in quantum circuits Mi, Xiao; Roushan, Pedram; Quintana, Chris ...
Science (American Association for the Advancement of Science),
2021-Dec-17, 2021-12-17, 20211217, Letnik:
374, Številka:
6574
Journal Article
Recenzirano
Odprti dostop
Interactions in quantum systems can spread initially localized quantum information into the exponentially many degrees of freedom of the entire system. Understanding this process, known as quantum ...scrambling, is key to resolving several open questions in physics. Here, by measuring the time-dependent evolution and fluctuation of out-of-time-order correlators, we experimentally investigate the dynamics of quantum scrambling on a 53-qubit quantum processor. We engineer quantum circuits that distinguish operator spreading and operator entanglement and experimentally observe their respective signatures. We show that whereas operator spreading is captured by an efficient classical model, operator entanglement in idealized circuits requires exponentially scaled computational resources to simulate. These results open the path to studying complex and practically relevant physical observables with near-term quantum processors.
Costa et al measured transmural distributions of three-dimensional residual strains by using biplane radiography of columns of lead beads implanted in the midanterior free wall of the canine left ...ventricle (LV). Relatively small residual shear strains with respect to the myofiber sheets suggest that prestretching in the plane of the myocardial laminae may be a primary mechanism of residual stress in the LV.
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