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SuperTIGER instrument abundances of galactic cosmic rays for the charge interval 41 ⩽ Z ⩽ 56
No full textWe report preliminary elemental abundance results from the 55-day long-duration-balloon flight of SuperTIGER (Super Trans-Iron Galactic Element Recorder) during the 2012–2013 austral summer. SuperTIGER measured the relative abundances of Galactic cosmic-ray (GCR) nuclei with high statistical precision and well resolved individual element peaks from ₁₀Ne to ₄₀Zr. SuperTIGER also made exploratory measurements of the relative abundances up to 56Ba. Although the statistics are low for elements heavier than ₄₀Zr, we present, for the first time, relative abundance measurements of charges Z = 41 - 56 with individual element resolution. GCR measurements up to ₄₀Zr support a source acceleration model where supernovae in OB associations preferentially accelerate refractory elements that are more readily embedded in interstellar dust grains than volatiles. In addition, injection into the GCR for both refractory and volatile elements appears to follow a charge dependence consistent with their grain sputtering cross sections. By extending the GCR measurement range past ₄₀Zr, we can begin to further constrain these models
First release of Apertif imaging survey data
No full textContext. Apertif is a phased-array feed system for the Westerbork Synthesis Radio Telescope, providing forty instantaneous beams over 300 MHz of bandwidth. A dedicated survey program utilizing this upgrade started on 1 July 2019, with the last observations taken on 28 February 2022. The imaging survey component provides radio continuum, polarization, and spectral line data.
Aims. Public release of data is critical for maximizing the legacy of a survey. Toward that end, we describe the release of data products from the first year of survey operations, through 30 June 2020. In particular, we focus on defining quality control metrics for the processed data products.
Methods. The Apertif imaging pipeline, Apercal, automatically produces non-primary beam corrected continuum images, polarization images and cubes, and uncleaned spectral line and dirty beam cubes for each beam of an Apertif imaging observation. For this release, processed data products are considered on a beam-by-beam basis within an observation. We validate the continuum images by using metrics that identify deviations from Gaussian noise in the residual images. If the continuum image passes validation, we release all processed data products for a given beam. We apply further validation to the polarization and line data products and provide flags indicating the quality of those data products.
Results. We release all raw observational data from the first year of survey observations, for a total of 221 observations of 160 independent target fields, covering approximately one thousand square degrees of sky. Images and cubes are released on a per beam basis, and 3374 beams (of 7640 considered) are released. The median noise in the continuum images is 41.4 uJy beam⁻¹, with a slightly lower median noise of 36.9 uJy beam⁻¹ in the Stokes V polarization image. The median angular resolution is 11.6″/sin δ. The median noise for all line cubes, with a spectral resolution of 36.6 kHz, is 1.6 mJy beam⁻¹, corresponding to a 3-σ H ɪ column density sensitivity of 1.8 × 10²⁰ atoms cm⁻² over 20 km s⁻¹ (for a median angular resolution of 24″ × 15″). Line cubes at lower frequency have slightly higher noise values, consistent with the global RFI environment and overall Apertif system performance. We also provide primary beam images for each individual Apertif compound beam. The data are made accessible using a Virtual Observatory interface and can be queried using a variety of standard tools
Vegetation clumping modulates global photosynthesis through adjusting canopy light environment
No full textThe spatial dispersion of photoelements within a vegetation canopy, quantified by the clumping index (CI), directly regulates the within-canopy light environment and pho-tosynthesis rate, but is not commonly implemented in terrestrial biosphere models to estimate the ecosystem carbon cycle. A few global CI products have been developed recently with remote sensing measurements, making it possible to examine the global impacts of CI. This study deployed CI in the radiative transfer scheme of the Community Land Model version 5 (CLM5) and used the revised CLM5 to quantitatively evaluate the extent to which CI can affect canopy absorbed radiation and gross primary production (GPP), and for the first time, considering the uncertainty and seasonal variation of CI with multiple remote sensing products. Compared to the results without considering the CI impact, the revised CLM5 estimated that sunlit canopy absorbed up to 9-15 and 23-34 less direct and diffuse radiation, respectively, while shaded canopy absorbed 3-18 more diffuse radiation across different biome types. The CI impacts on canopy light conditions included changes in canopy light absorption , and sunlit-shaded leaf area fraction related to nitrogen distribution and thus the maximum rate of Rubisco carboxylase activity (V꜀ₘₐₓ), which together decreased photosynthesis in sunlit canopy by 5.9-7.2 PgC year⁻¹ while enhanced photosynthesis by 6.9-8.2 PgC year⁻¹ in shaded canopy. With higher light use efficiency of shaded leaves, shaded canopy increased photosynthesis compensated and exceeded the lost photosynthesis in sunlit canopy, resulting in 1.0 ± 0.12 PgC year⁻¹ net increase in GPP. The uncertainty of GPP due to the different input CI datasets was much larger than that caused by CI seasonal variations, and was up to 50% of the magnitude of GPP interannual variations in the tropical regions. This study highlights the necessity of considering the impacts of CI and its uncertainty in terrestrial biosphere models
High-resolution spectroscopy of buffer-gas-cooled phthalocyanine
No full textFor over five decades, studies in the field of chemical physics and physical chemistry have primarily aimed to understand the quantum properties of molecules. However, high-resolution rovibronic spectroscopy has been limited to relatively small and simple systems because translationally and rotationally cold samples have not been prepared in sufficiently large quantities for large and complex systems. In this study, we present high-resolution rovibronic spectroscopy results for large gas-phase molecules, namely, free-base phthalocya-nine (FBPc). The findings suggest that buffer-gas cooling may be effective for large molecules introduced via laser ablation. High-resolution electronic spectroscopy, combined with other experimental and theoretical studies, will be useful in understanding the quantum properties of molecules. These findings also serve as a guide for quantum chemical calculations of large molecules
The temporal dynamics of the sea urchin regulome
No full textIn this work, we used Nanostring N-counter technology, to evaluate the mRNA expression level of more than 330 regulatory genes over 34 time points covering the first three days of development of the sea urchin larvae. The hierarchical clustering of the mRNAs expression levels has identified groups corresponding to the major developmental landmarks (e.g. maternal to zygotic transition and gastrulation). Furthermore, comparison with previous experiments indicates high reproducibility of mRNA level temporal dynamics across batches. Finally, we generated an online tool to visualise gene expression during sea urchin larval development. The site can be accessed at and https://www621.lamp.le.ac.uk/nanostring_app/nanostring/
Nano-electromechanical spatial light modulator enabled by asymmetric resonant dielectric metasurfaces
No full textSpatial light modulators (SLMs) play essential roles in various free-space optical technologies, offering spatio-temporal control of amplitude, phase, or polarization of light. Beyond conventional SLMs based on liquid crystals or microelectromechanical systems, active metasurfaces are considered as promising SLM platforms because they could simultaneously provide high-speed and small pixel size. However, the active metasurfaces reported so far have achieved either limited phase modulation or low efficiency. Here, we propose nano-electromechanically tunable asymmetric dielectric metasurfaces as a platform for reflective SLMs. Exploiting the strong asymmetric radiation of perturbed high-order Mie resonances, the metasurfaces experimentally achieve a phase-shift close to 290∘, over 50% reflectivity, and a wavelength-scale pixel size. Electrical control of diffraction patterns is also achieved by displacing the Mie resonators using nano-electro-mechanical forces. This work paves the ways for future exploration of the asymmetric metasurfaces and for their application to the next-generation SLMs
Regulatory non-coding RNAs: everything is possible, but what is important?
No full textIn recent years, the number of annotated noncoding RNAs (ncRNAs) and RNA-binding proteins (RBPs) has increased dramatically. The wide range of RBPs identified highlights the enormous potential for RNA in virtually all aspects of cell biology, from transcriptional regulation to metabolic control. Yet, there is a growing gap between what is possible and what has been demonstrated to be functionally important. Here we highlight recent methodological developments in the study of RNA–protein interactions, discuss the challenges and opportunities for exploring their functional roles, and provide our perspectives on what is needed to bridge the gap in this rapidly expanding field
The spherical Plateau problem for group homology
No full textGiven a group homology class h of a countable group Γ, we study a corresponding homological Plateau problem inside a canonical classifying space of Γ, which is defined using the regular representation of Γ and which is locally isometric to a Hilbert unit sphere. We investigate the relation between group theoretic properties of the pair (Γ,h) and the geometry of its Plateau solutions. For instance, we prove that for a closed oriented 3-manifold M, the intrinsic geometry of any Plateau solution is given by the hyperbolic part of M endowed with one third of its hyperbolic metric
Magnetic braking saturates: evidence from the orbital period distribution of low-mass detached eclipsing binaries from ZTF
No full textWe constrain the orbital period (Porb) distribution of low-mass detached main-sequence eclipsing binaries (EBs) with light-curves from the Zwicky Transient Facility (ZTF), which provides a well-understood selection function and sensitivity to faint stars. At short periods (Porb ≲ 2 d), binaries are predicted to evolve significantly due to magnetic braking (MB), which shrinks orbits and ultimately brings detached binaries into contact. The period distribution is thus a sensitive probe of MB. We find that the intrinsic period distribution of low-mass (0.1 ≲ M_(1)/M_(⊙) < 0.9) binaries is basically flat (dN/dP_(orb) ∝ P^(0)_(orb)) from P_(orb) = 10 d down to the contact limit. This is strongly inconsistent with predictions of classical MB models based on the Skumanich relation, which are widely used in binary evolution calculations and predict dN/dP_(orb) ∝ P^(7/3)_(orb) at short periods. The observed distributions are best reproduced by models in which the magnetic field saturates at short periods with a MB torque that scales roughly as J˙ ∝ P^(−1)_(orb), as opposed to J˙ ∝ P^(−3)_(orb) in the standard Skumanich law. We also find no significant difference between the period distributions of binaries containing fully and partially convective stars. Our results confirm that a saturated MB law, which was previously found to describe the spin-down of rapidly rotating isolated M dwarfs, also operates in tidally locked binaries. We advocate using saturated MB models in binary evolution calculations. Our work supports previous suggestions that MB in cataclysmic variables (CVs) is much weaker than assumed in the standard evolutionary model, unless mass transfer leads to significant additional angular momentum loss in CVs
Standardized multi-omics of Earth’s microbiomes reveals microbial and metabolite diversity
No full textDespite advances in sequencing, lack of standardization makes comparisons across studies challenging and hampers insights into the structure and function of microbial communities across multiple habitats on a planetary scale. Here we present a multi-omics analysis of a diverse set of 880 microbial community samples collected for the Earth Microbiome Project. We include amplicon (16S, 18S, ITS) and shotgun metagenomic sequence data, and untargeted metabolomics data (liquid chromatography-tandem mass spectrometry and gas chromatography mass spectrometry). We used standardized protocols and analytical methods to characterize microbial communities, focusing on relationships and co-occurrences of microbially related metabolites and microbial taxa across environments, thus allowing us to explore diversity at extraordinary scale. In addition to a reference database for metagenomic and metabolomic data, we provide a framework for incorporating additional studies, enabling the expansion of existing knowledge in the form of an evolving community resource. We demonstrate the utility of this database by testing the hypothesis that every microbe and metabolite is everywhere but the environment selects. Our results show that metabolite diversity exhibits turnover and nestedness related to both microbial communities and the environment, whereas the relative abundances of microbially related metabolites vary and co-occur with specific microbial consortia in a habitat-specific manner. We additionally show the power of certain chemistry, in particular terpenoids, in distinguishing Earth’s environments (for example, terrestrial plant surfaces and soils, freshwater and marine animal stool), as well as that of certain microbes including Conexibacter woesei (terrestrial soils), Haloquadratum walsbyi (marine deposits) and Pantoea dispersa (terrestrial plant detritus). This Resource provides insight into the taxa and metabolites within microbial communities from diverse habitats across Earth, informing both microbial and chemical ecology, and provides a foundation and methods for multi-omics microbiome studies of hosts and the environment