2,152 research outputs found
Editorial: If the settler never came
If the settler never came and the (Australian) continent developed herself, what kinds of conversations would we consider? Perhaps, we would highlight the fact that the Country and Island landscape did not have an estimated number of languages but significantly more than the speculated 250 (or “over 300”, or “hundreds of”) Aboriginal and Torres Strait Islander languages across the island and continental landscape. It would be a given continuance that every year across the Country, and not just 2019 declared by the United Nations General assembly, as the year to celebrate the Indigenous languages. Perhaps the ways we define, discuss and distinguish these numerous, living languages would be very different from our current forensic approaches
Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC
The uncertainty on the calorimeter energy response to jets of particles is
derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the
calorimeter response to single isolated charged hadrons is measured and
compared to the Monte Carlo simulation using proton-proton collisions at
centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009
and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter
response to specific types of particles (positively and negatively charged
pions, protons, and anti-protons) is measured and compared to the Monte Carlo
predictions. Finally, the jet energy scale uncertainty is determined by
propagating the response uncertainty for single charged and neutral particles
to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3%
for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table,
submitted to European Physical Journal
Implementation and Validation of a High Accuracy UAV-Photogrammetry Based Rail Track Inspection System
The regular inspection of the crane tracks of storage cranes at the Container Terminal Altenwerder (CTA), Hamburg requires high accuracy of measurements to determine its position. The allowed tolerances are in the range of 10 mm in the XY plane on a track length of 300 m. The traditional semi-automatic surveying methods are slow and require the interruption of the activities in the storage blocks. The research project AeroInspekt proposed a fully automatic measurement of the position of the tracks using UAV-based photogrammetry. In this paper, the results of the test campaign, carried out in June 2020, were presented where different cameras (150 mm and 80 mm telelens) and flight speeds (1.1 m/s and 1.9 m/s) at a 35 m flying height were performed. Furthermore, an automated rail delineation in the derived surface model was developed and evaluated with ground reference measurements. The results show that the required accuracy of the rail position with an RMSE of 3 mm in XY plane and 8 mm in altitude can be achieved with comparatively less disruption of regular block activities
iOD907, the first genome-scale metabolic model for the milk yeast Kluyveromyces lactis
We describe here the first genome-scale metabolic model of Kluyveromyces lactis, iOD907. It is partially compartmentalized (4 compartments), composed of 1867 reactions and 1476 metabolites. The iOD907 model performed well when assessing the positive growth of K. lactis to Biolog experiments and to an online catalogue of strains that provides information on carbon sources in which K. lactis is able to grow. Chemostat experiments were used to adjust non-growth-associated energy requirements, and the model proved accurate when predicting the biomass, oxygen and carbon dioxide yields. In silico knockouts predicted in vivo phenotypes accurately when compared to published experiments. The iOD907 genome-scale metabolic model complies with the MIRIAM standards for the annotation of enzymes, transporters, metabolites and reactions. Moreover, it contains direct links to KEGG (for enzymes, metabolites and reactions) and to TCDB for transporters, allowing easy comparisons to other models. Furthermore, this model is provided in the well-established SBML format, which means that it can be used in most metabolic engineering platforms, such as OptFlux or Cobra. The model is able to predict the behavior of K. lactis under different environmental conditions and genetic perturbations. Furthermore, it can also be important in the design of minimal media and will allow insights on the milk yeast's metabolism, as well as identifying metabolic engineering targets for the improvement of the production of products of interest by performing simulations and optimizations.The authors thank strategic Project PEst-OE/EQB/LA0023/2013 and project "BioInd - Biotechnology and Bioengineering for improved Industrial and Agro-Food processes, REF. NORTE-07-0124-FEDER-000028" co-funded by the Programa Operacional Regional do Norte (ON.2 - O Novo Norte), QREN, FEDER. The authors would also like to acknowledge Steve Sheridan for proof reading this manuscript
CEERS: Diversity of Lyman-Alpha Emitters during the Epoch of Reionization
We analyze rest-frame ultraviolet to optical spectra of three -
galaxies whose Ly-emission lines were previously detected with
Keck/MOSFIRE observations, using the JWST/NIRSpec observations from the Cosmic
Evolution Early Release Science (CEERS) survey. From NIRSpec data, we confirm
the systemic redshifts of these Ly emitters, and emission-line ratio
diagnostics indicate these galaxies were highly ionized and metal poor. We
investigate Ly line properties, including the line flux, velocity
offset, and spatial extension. For the one galaxy where we have both NIRSpec
and MOSFIRE measurements, we find a significant offset in their flux
measurements ( greater in MOSFIRE) and a marginal difference in
the velocity shifts. The simplest interpretation is that the Ly
emission is extended and not entirely encompassed by the NIRSpec slit. The
cross-dispersion profiles in NIRSpec reveal that Ly in one galaxy is
significantly more extended than the non-resonant emission lines. We also
compute the expected sizes of ionized bubbles that can be generated by the
Ly sources, discussing viable scenarios for the creation of sizable
ionized bubbles (1 physical Mpc). The source with the highest-ionization
condition is possibly capable of ionizing its own bubble, while the other two
do not appear to be capable of ionizing such a large region, requiring
additional sources of ionizing photons. Therefore, the fact that we detect
Ly from these galaxies suggests diverse scenarios on escape of
Ly during the epoch of reionization. High spectral resolution spectra
with JWST/NIRSpec will be extremely useful for constraining the physics of
patchy reionization.Comment: Submitted to ApJ (18 pages, 7 figures, 2 tables
CEERS Key Paper VII: Emission Line Ratios from NIRSpec and NIRCam Wide-Field Slitless Spectroscopy at z>2
We use James Webb Space Telescope Near-Infrared Camera Wide Field Slitless
Spectroscopy (NIRCam WFSS) and Near-Infrared spectrograph (NIRSpec) in the
Cosmic Evolution Early Release survey (CEERS) to measure rest-frame optical
emission-line of 155 galaxies at z>2. The blind NIRCam grism observations
include a sample of galaxies with bright emission lines that were not observed
on the NIRSpec masks. We study the changes of the Ha, [OIII]/Hb, and
[NeIII]/[OII] emission lines in terms of redshift by comparing to lower
redshift SDSS and CLEAR samples. We find a significant (>3) correlation
between [OIII]/Hb with redshift, while [NeIII]/[OII] has a marginal (2)
correlation with redshift. We compare [OIII]/Hb and [NeIII]/[OII] to stellar
mass and Hb SFR. We find that both emission-line ratios have a correlation with
Hb SFR and an anti-correlation with stellar mass across the redshifts 0<z<9.
Comparison with MAPPINGS~V models indicates that these trends are consistent
with lower metallicity and higher ionization in low-mass and high-SFR galaxies.
We additionally compare to IllustriousTNG predictions and find that they
effectively describe the highest [OIII]/Hb ratios observed in our sample,
without the need to invoke MAPPINGS models with significant shock ionizionation
components.Comment: 16 pages, 11 figure
CEERS Spectroscopic Confirmation of NIRCam-Selected z > 8 Galaxy Candidates with JWST/NIRSpec: Initial Characterization of their Properties
We present JWST NIRSpec spectroscopy for 11 galaxy candidates with
photometric redshifts of and newly
identified in NIRCam images in the Cosmic Evolution Early Release Science
(CEERS) Survey. We confirm emission line redshifts for 7 galaxies at
using spectra at m either with the NIRSpec prism or
its three medium resolution gratings. For photometric candidates, we
achieve a high confirmation rate of 90\%, which validates the classical
dropout selection from NIRCam photometry. No robust emission lines are
identified in three galaxy candidates at , where the strong [OIII] and
H lines would be redshifted beyond the wavelength range observed by
NIRSpec, and the Lyman- continuum break is not detected with the
current sensitivity. Compared with HST-selected bright galaxies
() that are similarly spectroscopically confirmed at
, these NIRCam-selected galaxies are characterized by lower star
formation rates (SFR~yr) and lower stellar masses
(), but with higher [OIII]+H equivalent widths
(1100), and elevated production efficiency of ionizing photons
() induced by young stellar
populations (~Myrs) accounting for of the galaxy mass,
highlighting the key contribution of faint galaxies to cosmic reionization.
Taking advantage of the homogeneous selection and sensitivity, we also
investigate metallicity and ISM conditions with empirical calibrations using
the [OIII]/H ratio. We find that galaxies at have higher SFRs
and lower metallicities than galaxies at similar stellar masses at ,
which is generally consistent with the current galaxy formation and evolution
models.Comment: 21 pages, 11 figures, 2 tables. Submitted to ApJL Focus Issu
First Look at z > 1 Bars in the Rest-frame Near-infrared with JWST Early CEERS Imaging
Stellar bars are key drivers of secular evolution in galaxies and can be effectively studied using rest-frame near-infrared (NIR) images, which trace the underlying stellar mass and are less impacted by dust and star formation than rest-frame UV or optical images. We leverage the power of JWST CEERS NIRCam images to present the first quantitative identification and characterization of stellar bars at z > 1 based on rest-frame NIR F444W images of high resolution (∼1.3 kpc at z ∼ 1-3). We identify stellar bars in these images using quantitative criteria based on ellipse fits. For this pilot study, we present six examples of robustly identified bars at z > 1 with spectroscopic redshifts, including the two highest-redshift bars at z ∼ 2.136 and 2.312 quantitatively identified and characterized to date. The stellar bars at z ∼ 1.1-2.3 presented in our study have projected semimajor axes of ∼2.9-4.3 kpc and projected ellipticities of ∼0.41-0.53 in the rest-frame NIR. The barred host galaxies have stellar masses ∼1 × 10 10 to 2 × 10 11 M ⊙ and star formation rates of ∼21-295 M ⊙ yr −1, and several have potential nearby companions. Our finding of bars at z ∼ 1.1-2.3 demonstrates the early onset of such instabilities and supports simulations where bars form early in massive dynamically cold disks. It also suggests that if these bars at lookback times of 8-11 Gyr survive out to present epochs, bar-driven secular processes may operate over a long time and have a significant impact on some galaxies by z ∼ 0.</p
First Look at z > 1 Bars in the Rest-Frame Near-Infrared with JWST Early CEERS Imaging
Stellar bars are key drivers of secular evolution in galaxies and can be
effectively studied using rest-frame near-infrared (NIR) images, which trace
the underlying stellar mass and are less impacted by dust and star formation
than rest-frame UV or optical images. We leverage the power of {\it{JWST}}
CEERS NIRCam images to present the first quantitative identification and
characterization of stellar bars at based on rest-frame NIR F444W images
of high resolution (~1.3 kpc at z ~ 1-3). We identify stellar bars in these
images using quantitative criteria based on ellipse fits. For this pilot study,
we present six examples of robustly identified bars at with spectroscopic
redshifts, including the two highest redshift bars at ~2.136 and 2.312
quantitatively identified and characterized to date. The stellar bars at ~
1.1-2.3 presented in our study have projected semi-major axes of ~2.9-4.3 kpc
and projected ellipticities of ~0.41-0.53 in the rest-frame NIR. The barred
host galaxies have stellar masses ~ to
, star formation rates of ~ 21-295 yr, and
several have potential nearby companions. Our finding of bars at ~1.1-2.3
demonstrates the early onset of such instabilities and supports simulations
where bars form early in massive dynamically cold disks. It also suggests that
if these bars at lookback times of 8-10 Gyr survive out to present epochs,
bar-driven secular processes may operate over a long time and have a
significant impact on some galaxies by z ~ 0.Comment: 16 pages, 5 figures. Accepted for Publication in Astrophysical
Journal Letter
- …
