2,226 research outputs found
Star Formation in a Stellar Mass Selected Sample of Galaxies to z=3 from the GOODS NICMOS Survey (GNS)
We present a study of the star-forming properties of a stellar mass-selected
sample of galaxies in the GOODS NICMOS Survey (GNS), based on deep Hubble Space
Telescope imaging of the GOODS North and South fields. Using a stellar mass
selected sample, combined with HST/ACS and Spitzer data to measure both UV and
infrared derived star formation rates (SFR), we investigate the star forming
properties of a complete sample of ~1300 galaxies down to log M*=9.5 at
redshifts 1.5<z<3. Eight percent of the sample is made up of massive galaxies
with M*>10^11 Msun. We derive optical colours, dust extinctions, and
ultraviolet and infrared SFR to determine how the star formation rate changes
as a function of both stellar mass and time. Our results show that SFR
increases at higher stellar mass such that massive galaxies nearly double their
stellar mass from star formation alone over the redshift range studied, but the
average value of SFR for a given stellar mass remains constant over this 2 Gyr
period. Furthermore, we find no strong evolution in the SFR for our sample as a
function of mass over our redshift range of interest, in particular we do not
find a decline in the SFR among massive galaxies, as is seen at z < 1. The most
massive galaxies in our sample (log M*>11) have high average SFRs with values,
SFR(UV,corr) = 103+/-75 Msun/yr, yet exhibit red rest-frame (U-B) colours at
all redshifts. We conclude that the majority of these red high-redshift massive
galaxies are red due to dust extinction. We find that A(2800) increases with
stellar mass, and show that between 45% and 85% of massive galaxies harbour
dusty star formation. These results show that even just a few Gyr after the
first galaxies appear, there are strong relations between the global physical
properties of galaxies, driven by stellar mass or another underlying feature of
galaxies strongly related to the stellar mass.Comment: 18 pages, 10 figures, accepted for publication in MNRA
Molecular causality in the advent of foundation models
Correlation is not causation. As simple as this widely agreed-upon statement
may seem, scientifically defining causality and using it to drive our modern
biomedical research is immensely challenging. In this perspective, we attempt
to synergise the partly disparate fields of systems biology, causal reasoning,
and machine learning, to inform future approaches in the field of systems
biology and molecular networks.Comment: 22 pages, 0 figures, 87 references; submitted to MS
Coherent modulation of the electron temperature and electron-phonon couplings in a 2D material
Ultrashort light pulses can selectively excite charges, spins and phonons in
materials, providing a powerful approach for manipulating their properties.
Here we use femtosecond laser pulses to coherently manipulate the electron and
phonon distributions, and their couplings, in the charge density wave (CDW)
material 1T-TaSe. After exciting the material with a short light pulse,
spatial smearing of the electrons launches a coherent lattice breathing mode,
which in turn modulates the electron temperature. This indicates a
bi-directional energy exchange between the electrons and the strongly-coupled
phonons. By tuning the laser excitation fluence, we can control the magnitude
of the electron temperature modulation, from ~ 200 K in the case of weak
excitation, to ~ 1000 K for strong laser excitation. This is accompanied by a
switching of the dominant mechanism from anharmonic phonon-phonon coupling to
coherent electron-phonon coupling, as manifested by a phase change of in
the electron temperature modulation. Our approach thus opens up possibilities
for coherently manipulating the interactions and properties of quasi-2D and
other quantum materials using light.Comment: 15 pages, 4 figure
Modules for Experiments in Stellar Astrophysics (MESA): Convective Boundaries, Element Diffusion, and Massive Star Explosions
We update the capabilities of the software instrument Modules for Experiments
in Stellar Astrophysics (MESA) and enhance its ease of use and availability.
Our new approach to locating convective boundaries is consistent with the
physics of convection, and yields reliable values of the convective core mass
during both hydrogen and helium burning phases. Stars with
become white dwarfs and cool to the point where the electrons are degenerate
and the ions are strongly coupled, a realm now available to study with MESA due
to improved treatments of element diffusion, latent heat release, and blending
of equations of state. Studies of the final fates of massive stars are extended
in MESA by our addition of an approximate Riemann solver that captures shocks
and conserves energy to high accuracy during dynamic epochs. We also introduce
a 1D capability for modeling the effects of Rayleigh-Taylor instabilities that,
in combination with the coupling to a public version of the STELLA radiation
transfer instrument, creates new avenues for exploring Type II supernovae
properties. These capabilities are exhibited with exploratory models of
pair-instability supernova, pulsational pair-instability supernova, and the
formation of stellar mass black holes. The applicability of MESA is now widened
by the capability of importing multi-dimensional hydrodynamic models into MESA.
We close by introducing software modules for handling floating point exceptions
and stellar model optimization, and four new software tools -- MESAWeb,
MESA-Docker, pyMESA, and mesastar.org -- to enhance MESA's education and
research impact.Comment: 64 pages, 61 figures; Accepted to AAS Journal
Restrictive diets are unnecessary for colonoscopy: Non-inferiority randomized trial
Endoscopy Lower GI Tract; CRC screening; Quality and logistical aspectsEndoscopia tracto gastrointestinal inferior; Cribado CCR; Aspectos logĂsticosEndoscòpia tracte gastrointestinal inferior; Cribratge CCR; Qualitat i aspectes logĂsticsBackground and study aims In colonoscopy, preparation is often regarded as the most burdensome part of the intervention. Traditionally, specific diets have been recommended, but the evidence to support this policy is insufficient. The aim of this study was to evaluate the impact of the decision not to follow a restrictive diet on bowel preparation and colonoscopy outcomes. Patients and methods This was a multicenter, controlled, non-inferiority randomized trial with FIT-positive screening colonoscopy. The subjects were assigned to follow the current standard (1-day low residue diet [LRD]) or a liberal diet. The allocation was balanced for the risk of inadequate cleansing using the Dik et al. score. All participants received the same instructions for morning colonoscopy preparation. The primary outcome was the rate of adequate preparations as defined by the Boston Bowel Preparation Scale. Secondary outcomes included tolerability and measures of colonoscopy performance and quality. Results A total of 582 subjects were randomized. Of these, 278 who received the liberal diet and 275 who received the 1-day LRD were included in the intent-to-treat analysis. Non-inferiority was demonstrated with adequate preparation rates of 97.8% in the 1-day LRD and 96.4% in the liberal diet group. Tolerability was higher with the liberal diet (94.7% vs. 83.2%). No differences were found with respect to cecal intubation time, aspirated volume, or length of the examination. Global and right colon average adenoma detection rates per colonoscopy were similar. Conclusions The liberal diet was non-inferior to the 1-day LRD, and increased tolerability. Colonoscopy performance and quality were not affected. (NCT05032794)
Adenovirus core protein V reinforces the capsid and enhances genome release from disrupted particles
Out of the three core proteins in human adenovirus, protein V is believed to connect the inner capsid surface to the outer genome layer. Here, we explored mechanical properties and in vitro disassembly of particles lacking protein V (Ad5-ΔV). Ad5-ΔV particles were softer and less brittle than the wild-type ones (Ad5-wt), but they were more prone to release pentons under mechanical fatigue. In Ad5-ΔV, core components did not readily diffuse out of partially disrupted capsids, and the core appeared more condensed than in Ad5-wt. These observations suggest that instead of condensing the genome, protein V antagonizes the condensing action of the other core proteins. Protein V provides mechanical reinforcement and facilitates genome release by keeping DNA connected to capsid fragments that detach during disruption. This scenario is in line with the location of protein V in the virion and its role in Ad5 cell entry
Adenovirus core protein V reinforces the capsid and enhances genome release from disrupted particles
Out of the three core proteins in human adenovirus, protein V is believed to connect the inner capsid surface to the outer genome layer. Here, we explored mechanical properties and in vitro disassembly of particles lacking protein V (Ad5-ΔV). Ad5-ΔV particles were softer and less brittle than the wild-type ones (Ad5-wt), but they were more prone to release pentons under mechanical fatigue. In Ad5-ΔV, core components did not readily diffuse out of partially disrupted capsids, and the core appeared more condensed than in Ad5-wt. These observations suggest that instead of condensing the genome, protein V antagonizes the condensing action of the other core proteins. Protein V provides mechanical reinforcement and facilitates genome release by keeping DNA connected to capsid fragments that detach during disruption. This scenario is in line with the location of protein V in the virion and its role in Ad5 cell entryThis work was supported by grants from the Spanish Ministry of Economy, Industry and Competitiveness (FIS2017-89549-R; “Maria de Maeztu” Program for Units of Excellence in R&D MDM-2014-0377 and FIS2017-90701-REDT) and from the Human Frontiers Science Program (HFSPO RGP0012/2018) to P.J.d.P., as well as grant PID2019-104098GB-I00/AEI/10.13039/501100011033, cofunded by the Spanish State Research Agency and the European Regional Development Fund to C.S.M. The CNB-CSIC was further supported by a Spanish State Research Agency Severo Ochoa Excellence grant (SEV 2017-0712). C.S.M. is a member of the CSIC funded consortium LifeHub (CSIC grant number: 202120E47). M.H.-P. was a recipient of a Juan de la Cierva postdoctoral contract and currently holds a Ramón y Cajal position (RyC2021-030929-I) funded by the Spanish State Research Agency. M.H.-P. acknowledges funding from Ayudas a Proyectos de I+D para Jóvenes Doctores de la Universidad Autónoma de Madrid 2021, SI3/PJI/2021-00216 supported by the Community of Madrid and the University Autónoma de Madrid, and TED2021-129937B-I00 from Spanish Ministry of Science and Innovation. Financial support of the Community of Madrid and the European Union through the European Regional Development Fund (ERDF), financed as part of the Union response to Covid-19 pandemic (VIRMAT-REACT), is also acknowledged. Access to the cryo-EM CNB-CSIC facility was carried out via the CRIOMECORR project (ESFRI-2019-01- CSIC-16). Work in the Greber laboratory was supported by a grant to UFG from Schweizerischer Nationalfonds (Swiss National Science Foundation, 31003A_179256/1). Author contributions: N.M.-G. performed AFM experiments and analyzed the data. M.H.-P. and C.S.M. carried out cryoEM analyses. A.G.-G. and M.B. produced the viral samples and carried out thermostability analyses. U.F.G., C.S.M., and P.J.d.P. designed research. N.M.-G. wrote the manuscript, with input from U.F.G., C.S.M., and P.J.d.P. All authors read and edited the manuscript. Competing interests: The authors declare that they have no competing interests. Data and materials availability: The Ad5-ΔV cryo-EM map is deposited at the Electron Microscopy Data Bank (EMDB; www.ebi.ac.uk/pdbe/emdb) with accession number EMD-15694. All data needed to evaluate the conclusions in the paper are present in the paper and/or the Supplementary Material
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