Search

We present results from a search for a radio transient associated with the LIGO/Virgo source S190814bv, a likely neutron star-black hole (NSBH) merger, with the Australian Square Kilometre Array Pathfinder. We imaged a 30 deg2 field at ΔT = 2, 9, and 33 days post-merger at a frequency of 944 MHz, comparing them to reference images from the Rapid ASKAP Continuum Survey observed 110 days prior to the event. Each epoch of our observations covers 89% of the LIGO/Virgo localization region. We conducted an untargeted search for radio transients in this field, resulting in 21 candidates. For one of these, AT2019osy, we performed multiwavelength follow-up and ultimately ruled out the association with S190814bv. All other candidates are likely unrelated variables, but we cannot conclusively rule them out. We discuss our results in the context of model predictions for radio emission from NSBH mergers and place constrains on the circum-merger density and inclination angle of the merger. This survey is simultaneously the first large-scale radio follow-up of an NSBH merger, and the most sensitive widefield radio transients search to-date.

Minorities are particularly vulnerable during times of emergency, particularly those that challenge the state. However, it is not understood how minorities can be targeted through emergency decrees despite the government agreeing they had nothing to do with the reasons for declaring the state of emergency. The Turkish emergency in 2016 highlights this little-understood tendency where the government constructed an emergency around a threat from coup plotters, but then much of the subsequent extraordinary legislation targeted the Kurdish minority. We argue that this was possible because the Turkish government engaged in modular emergency rule. Modular emergency rule combines modes of ordinary rule with emergency powers, thus blurring the boundaries between the two. Emergency measures were laid on top of already existing policies that sought to restrict Kurdish politics in public life. In this way, modular emergency rule became more than just a transient form of government. [ABSTRACT FROM AUTHOR]

We report an ASKAP search for associated H  i 21-cm absorption against bright radio sources from the Molonglo Reference Catalogue (MRC) 1-Jy sample. The search uses pilot survey data from the ASKAP First Large Absorption Survey in H  i (FLASH) covering the redshift range 0.42 < z < 1.00. From a sample of 62 MRC 1-Jy radio galaxies and quasars, we report three new detections of associated H  i 21-cm absorption, yielding an overall detection fraction of |$1.8\,{{\,\rm per\,cent}}^{+4.0\,{{\,\rm per\,cent}}}_{-1.5\,{{\,\rm per\,cent}}}$|⁠. The detected systems comprise two radio galaxies (MRC 2216−281 at z  = 0.657 and MRC 0531−237 at z  = 0.851) and one quasar (MRC 2156−245 at z  = 0.862). The MRC 0531−237 absorption system is the strongest found to date, with a velocity integrated optical depth of |$\rm 143.8 \pm 0.4 \ km \ s^{-1}$|⁠. All three objects with detected H  i 21-cm absorption are peaked-spectrum or compact steep-spectrum (CSS) radio sources. Two of them show strong interplanetary scintillation at 162 MHz, implying that the radio continuum source is smaller than 1 arcsec in size even at low frequencies. Among the class of peaked-spectrum and compact steep-spectrum radio sources, the H  i detection fraction is |$23\,{{\,\rm per\,cent}}^{+22\,{{\,\rm per\,cent}}}_{-13\,{{\,\rm per\,cent}}}$|⁠. All three detections have a high 1.4 GHz radio luminosity, with MRC 0531−237 and MRC 2216−281 having the highest values in the sample, |$\rm \gt 27.5 \ W \ Hz^{-1}$|⁠. The preponderance of extended radio sources in our sample could partially explain the overall low detection fraction, while the effects of a redshift evolution in gas properties and AGN UV luminosity on the neutral gas absorption still need to be investigated. [ABSTRACT FROM AUTHOR]

We present new upgraded Giant Metrewave Radio Telescope H  i 21-cm observations of the ultra-luminous infrared galaxy IRAS 10565 + 2448, previously reported to show blueshifted, broad, and shallow H  i absorption indicating an outflow. Our higher spatial resolution observations have localized this blueshifted outflow, which is ∼ 1.36 kpc southwest of the radio centre and has a blueshifted velocity of |$\sim 148\, \rm km\, s^{-1}$| and a full width at half maximum of |$\sim 581\, \rm km\, s^{-1}$|⁠. The spatial extent and kinematic properties of the H  i outflow are consistent with the previously detected cold molecular outflows in IRAS 10565 + 2448, suggesting that they likely have the same driving mechanism and are tracing the same outflow. By combining the multiphase gas observations, we estimate a total outflowing mass rate of at least |$140\, \rm M_\odot \, yr^{-1}$| and a total energy loss rate of at least |$8.9\times 10^{42}\, \rm erg\, s^{-1}$|⁠ , where the contribution from the ionized outflow is negligible, emphasizing the importance of including both cold neutral and molecular gas when quantifying the impact of outflows. We present evidence of the presence of a radio jet and argue that this may play a role in driving the observed outflows. The modest radio luminosity |$L_{\rm 1.4GHz}\, \sim 1.3\times 10^{23}\, {\rm W\, Hz^{-1}}$| of the jet in IRAS 10565 + 2448 implies that the jet contribution to driving outflows should not be ignored in low radio luminosity active galactic nuclei. [ABSTRACT FROM AUTHOR]

Explores the design option of channel choice or medium selection (delivering information in print or electronic form) and reports the results of two studies that examine customers' preferences and use of printed manuals and online help, common documents used in the computer software industry. Finds that users prefer different types of documentation for different types of tasks. (SG)

We present early science results from Deep Investigation of Neutral Gas Origins (DINGO), an |$\rm H$| i survey using the Australian Square Kilometre Array Pathfinder (ASKAP). Using ASKAP subarrays available during its commissioning phase, DINGO early science data were taken over ∼60 deg2 of the Galaxy And Mass Assembly (GAMA) 23 h region with 35.5 h integration time. We make direct detections of six known and one new sources at z < 0.01. Using |$\rm H$|   i spectral stacking, we investigate the |$\rm H$|   i gas content of galaxies at 0.04 < z < 0.09 for different galaxy colours. The results show that galaxy morphology based on optical colour is strongly linked to |$\rm H$|   i gas properties. To examine environmental impacts on the |$\rm H$| i gas content of galaxies, three subsamples are made based on the GAMA group catalogue. The average |$\rm H$| i mass of group central galaxies is larger than those of satellite and isolated galaxies, but with a lower |$\rm H$| i gas fraction. We derive a variety of |$\rm H$| i scaling relations for physical properties of our sample, including stellar mass, stellar mass surface density, NUV − r colour, specific star formation rate, and halo mass. We find that the derived |$\rm H$| i scaling relations are comparable to other published results, with consistent trends also observed to ∼0.5 dex lower limits in stellar mass and stellar surface density. The cosmic |$\rm H$| i densities derived from our data are consistent with other published values at similar redshifts. DINGO early science highlights the power of |$\rm H$| i spectral stacking techniques with ASKAP. [ABSTRACT FROM AUTHOR]

Cold damage has caused more economic losses to fruit crop growers in the U.S. than any other weather hazard, making it a perennial concern for producers. Cellulose nanocrystals (CNCs) represent a new generation of renewable bio-nanomaterials, with many unique physical and chemical properties, including their low thermal conductivity. Our team has developed a process for creating CNC dispersions that can be sprayed onto woody perennial crops, forming a thin insulating film around buds which has been shown to increase cold tolerance. Using digital scanning calorimetry (DSC) on dormant apple (Malus domestica Borkh.) reproductive buds, we investigated the thermodynamic properties of plant materials treated with CNC dispersion at lower temperatures. Scanning electron microscopy (SEM) was used to evaluate the thickness of the CNC films and their deposition on the sweet cherry bud surface. Apple buds treated with 3% CNC exhibited lethal freezing at temperatures 3.2°C and 5.5°C lower than the untreated control when sampled 1 and 3 days after application, respectively. Additionally, the latent heat capacity (J/g) of the 3% CNC-treated buds was 46% higher compared with untreated buds 1 day after application, and this difference increased 3 days after application to 168% higher. The emissivity of cherry buds treated with 3% CNC was reduced by an average of 16% compared with the untreated buds. SEM was able to detect the dried films on the surface of the buds 3 days after application. Film thickness measured with SEM increased with material concentration. The emissivity, HTE, and LTE results show that CNC-treated reproductive buds released thermal energy at a slower rate than the untreated Frontiers in buds and, consequently, exhibited internal ice nucleation events at temperatures as much as 5.5°C lower. The increased enthalpy during the LTE in the CNC-treated apple buds shows more energy released at lethal internal freezing, indicating that CNC coatings are increasing the amount of supercooled water. The effects of CNC shown during the DSC tests were increased by CNC concentration and time post-application. These results suggest that CNC dispersions dry into nanofilms on the bud surface, which affects their thermodynamic processes at low temperatures. [ABSTRACT FROM AUTHOR]

We present the results of a search for associated 21 cm H  i absorption at redshift 0.42 < z < 1.00 in radio-loud galaxies from three Galaxy And Mass Assembly (GAMA) survey fields. These observations were carried out as part of a pilot survey for the Australian SKA Pathfinder (ASKAP) First Large Absorption Survey in H  i (FLASH). From a sample of 326 radio sources with 855.5 MHz peak flux density above 10 mJy, we detected two associated H  i absorption systems, in SDSS J090331+010847 at z  = 0.522 and SDSS J113622+004852 at z  = 0.563. Both galaxies are massive (stellar mass |$\gt 10^{11}\, \mathrm{M}_\odot$|⁠) and have optical spectra characteristic of luminous red galaxies, though spectral energy distribution fitting implies that SDSS J113622+004852 contains a dust-obscured starburst with star formation rate ∼69 M⊙ yr−1. The H  i absorption lines have a high optical depth, with τpk of 1.77 ± 0.16 for SDSS J090331+010847 (the highest value for any z > 0.1 associated system found to date) and 0.14 ± 0.01 for SDSS J113622+004852. In the redshift range probed by our ASKAP observations, the detection rate for associated H  i absorption lines (with τpk > 0.1 and at least 3σ significance) is |$2.9_{-2.6}^{+9.7}$|  per cent. Although the current sample is small, this rate is consistent with a trend seen in other studies for a lower detection rate of associated 21 cm H  i absorption systems at higher redshift. We also searched for OH absorption lines at 0.67 < z < 1.34, but no detection was made in the 145 radio sources searched. [ABSTRACT FROM AUTHOR]

We present results from MUSE observations of a 21-cm |${\rm H\, {\small I}}$| absorption system detected with the Australian Square Kilometre Array Pathfinder radio telescope at redshift z  = 0.4503 towards the z  = 1.71 quasar PKS 1610-771. We identify four galaxies (A, B, X, and Y) at the same redshift as the 21-cm |${\rm H\, {\small I}}$| Damped Lyman-α (DLA) absorption system, with impact parameters ranging from less than 10 kpc to almost 200 kpc from the quasar sightline. |${\rm Ca\, {\small II}}$| and |${\rm Na\, {\small I}}$| absorption is seen in the MUSE spectrum of the background QSO, with velocities coinciding with the initial |${\rm H\, {\small I}}$| 21-cm detection, but tracing less dense and warmer gas. This metal-line component aligns with the rotating ionized disc of galaxy B (impact parameter 18 kpc from the QSO) and appears to be corotating with the galaxy disc. In contrast, the 21-cm |${\rm H\, {\small I}}$| absorber is blueshifted relative to the galaxies nearest the absorber and has the opposite sign to the velocity field of galaxy B. Since galaxies A and B are separated by only 17 kpc on the sky and 70 km s−1 in velocity, it appears likely that the 21-cm detection traces extragalactic clouds of gas formed from their interaction. This system reveals that the cold 100 K neutral gas critical for star formation can be associated with complex structures beyond the galaxy disc, and is a first case study made in preparation for future large 21-cm absorption surveys like the ASKAP First Large Absorption Survey in |${\rm H\, {\small I}}$|⁠. [ABSTRACT FROM AUTHOR]

Pollination is essential for the production of most fruit and nut crops, yet it is often a limiting factor for both yield and product quality. Mechanical pollination (MP) systems offer the potential to increase productivity of a broad range of horticultural fruit and nut crops, and to manage the risk of reliance on current insect pollination services. To date, commercial MP systems have been developed for only a few crops (e.g., kiwifruit and date palm), suggesting that innovation in the use of MP systems has been stymied. Here, we review published and 'grey' literature to investigate the feasibility of MP systems of economically important tree fruit and nut crops. This review found that, whilst MP systems are a commercial reality for a wider range of fruit crops (e.g., sweet cherry) than nut crops (e.g., almond), promising results have been achieved at the experimental scale. Further we identified that the key barriers for progressing MP systems more widely include knowledge gaps in pollination biology, particularly of emerging fruit and nut species that are grown outside their native distributions, and access to proprietorial knowledge gained by commercial operators. What continues to remain unclear is detailed knowledge of the commercial development of MP systems and therefore, the opportunities to apply this knowledge to other tree crops where effective pollination limits yield and quality. [ABSTRACT FROM AUTHOR]

We measure how the atomic gas (H i) fraction f H I = M H I M * of groups and pairs taken as single units vary with average stellar mass (〈 M *〉) and average star formation rate (〈SFR〉), compared to isolated galaxies. The H i 21 cm emission observation are from (i) archival ALFALFA survey data covering three fields from the GAMA survey (provides environmental and galaxy properties), and (ii) DINGO pilot survey data of one of those fields. The mean f H i for different units (groups/pairs/isolated galaxies) are measured in regions of the log(〈 M *〉)â€"log(〈SFR〉) plane, relative to the z ∼ 0 star-forming main sequence (SFMS) of individual galaxies, by stacking f H i spectra of individual units. For ALFALFA, f H i spectra of units are measured by extracting H i spectra over the full groups/pair areas and dividing by the total stellar mass of member galaxies. For DINGO, f H i spectra of units are measured by co-adding H i spectra of individual member galaxies, followed by division by their total stellar mass. For all units, the mean f H i decreases as we move to higher 〈 M *〉 along the SFMS and as we move from above the SFMS to below it at any 〈 M *〉. From the DINGO-based study, mean f H i in groups appears to be lower compared to isolated galaxies for all 〈 M *〉 along the SFMS. From the ALFALFA-based study, we find substantially higher mean f H i in groups compared to isolated galaxies (values for pairs being intermediate) for 〈 M *〉 ≲ 109.5 M ⊙, indicating the presence of substantial amounts of H i not associated with cataloged member galaxies in low mass groups. [ABSTRACT FROM AUTHOR]

Whether power-sharing increases polarisation or not in post-conflict societies remains deeply contested. Yet, we currently lack an adequate conceptualisation of polarisation to assess the link (if any) between the two. This article offers a new conceptualisation of polarisation and uses this to gather evidence from Northern Ireland to argue that the assumption that power-sharing entrenches polarisation is not the reality that many think it is. By examining legislator voting records, speeches by party leaders, manifestos and public opinion data, we disaggregate polarisation into different issues, track it over time, and examine both elite and mass levels. We find that overall polarisation declined, albeit some limited polarisation remained in cultural and identity issues, but these were of low salience. We argue that this is the result of parties using identity instrumentally for electoral distinction in a system of convergence – a process that is independent of the effects of power-sharing. [ABSTRACT FROM AUTHOR]

We present results from a search for the H  i 21-cm line in absorption towards 16 bright radio sources with the six-antenna commissioning array of the Australian Square Kilometre Array Pathfinder. Our targets were selected from the 2-Jy sample, a flux-limited survey of the southern radio sky with extensive multiwavelength follow-up. Two sources were detected in H  i absorption including a new detection towards the bright Fanaroff–Riley Type II radio galaxy PKS 0409−75 at a redshift of |$z$| = 0.674. The H  i absorption line is blueshifted by ∼3300 km s−1 compared to the optical redshift of the host galaxy of PKS 0409−75 at |$z$| = 0.693. Deep optical imaging and spectroscopic follow-up with the GMOS instrument on the Gemini-South telescope reveal that the H  i absorption is associated with a galaxy in front of the southern radio lobe with a stellar mass of 3.2–6.8 × 1011 M⊙, a star formation rate of ∼1.24 M⊙ yr−1, and an estimated H  i column density of 2.16 × 1021 cm−2, assuming a spin temperature of T spin = 500 K and source covering factor of C f = 0.3. Using polarization measurements of PKS 0409−75 from the literature, we estimate the magnetic field of the absorbing galaxy to be ∼14.5 |$\mu$| G, consistent with field strengths observed in nearby spiral galaxies but larger than expected for an elliptical galaxy. Results from this pilot study can inform future surveys as new wide-field telescopes allow us to search for 21-cm H  i absorption towards all bright radio sources as opposed to smaller targeted samples. [ABSTRACT FROM AUTHOR]

Modern broad acre farming operations have benefitted from technological innovations that have revolutionized production practices (e.g., harvesting combines). In contrast, tree fruit production processes remain highly dependent upon manual labor, particularly for critical perennial tasks like pruning and harvesting. The declining availability, and increasing cost, of skilled orchard labor for sweet cherry (Prunus avium L.) producers in Washington State, USA, have farmers concerned about the sustainability of their operations. At Washington State University, interdisciplinary teams have been investigating mechanical means for accomplishing key labor-intensive tasks, including harvest and pruning. This work has led to development of a novel canopy architecture that is compatible with both mechanical pruning and harvest systems. Herein I describe briefly our work on developing planar fruiting wall architectures for sweet cherry (e.g., the UFO system), and our research into mechanizing both pruning and harvest. Our work has shown tremendous potential to radically improve harvest and pruning efficiency without reductions in fruit quality or quantity, and suggests that there are sustainable solutions to address industry's concerns. [ABSTRACT FROM AUTHOR]

'WA 38' is a new apple (Malus domestica Borkh.) cultivar, released by Washington State University (WSU) in 2017. An unknown disorder, "green spot" (GS), dark green halos in the epidermis, with necrotic, corky, and oxidated cortical tissue underneath the damaged epidermis, leads to unmarketable fruit and has become a threat to the adoption and profitability of 'WA 38', with young and mature orchards exhibiting up to 60% incidence in 2020. Given the apparent susceptibility of 'WA 38' to GS, this research investigated GS relation with nutrient levels in fruit. Research was carried out in 2018 and 2019 in a 'WA 38' apple block planted in 2013, on 'Geneva 41' ('G.41') and 'M.9-Nic 29' ('M.9') rootstocks. In both years, fruit number per tree, fruit weight, and fruit diameter were evaluated in 18 trees per treatment, from both rootstocks. From each tree, fruit were classified for presence or absence of GS, and subsequently analyzed for nutrient concentration in the peel and in the flesh, nutrient extraction, and total nutrient content, on an individual apple basis. Apples with GS had higher nitrogen (N) and magnesium (Mg) levels in the peel, regardless of year and rootstock. Apples grown on 'G.41' rootstock exhibited higher GS incidence and reduced crop load in both years; reduced size and fruit diameter were exhibited only in 2018. Fruit on 'G.41' had higher N, potassium (K), and Mg in the flesh and higher N and Mg in the peel, with lower levels of calcium (Ca) in the flesh and peel; however, only in 2018, with no differences in 2019. GS in 'WA 38' apples appears to be another Ca-related disorder in which excessive vigor, rootstock, and N and Mg excess are predisposing factors for its development. [ABSTRACT FROM AUTHOR]

The harvesting of sweet cherry (Prunus avium L.) fruit is a labor-intensive process. The mechanical harvesting of sweet cherry fruit is feasible; however, it is dependent on the formation of an abscission zone at the fruit–pedicel junction. The natural propensity for pedicel—fruit abscission zone (PFAZ) activation varies by cultivar, and the general molecular basis for PFAZ activation is not well characterized. In this study, ethylene-inducible change in pedicel fruit retention force (PFRF) was recorded in a developmental time-course with a concomitant analysis of the PFAZ transcriptome from three sweet cherry cultivars. In ‘Skeena’, mean PFRF for both control and treatment fruit dropped below the 0.40 kg-force (3.92 N) threshold for mechanical harvesting, indicating the activation of a discrete PFAZ. In ‘Bing’, mean PFRF for both control and treatment groups decreased over time. However, a mean PFRF conducive to mechanical harvesting was achieved only in the ethylene-treated fruit. While in ‘Chelan’ the mean PFRF of the control and treatment groups did not meet the threshold required for efficient mechanical harvesting. Transcriptome analysis of the PFAZ region followed by the functional annotation, differential expression analysis, and gene ontology (GO) enrichment analyses of the data facilitated the identification of phytohormone-responsive and abscission-related transcripts, as well as processes that exhibited differential expression and enrichment in a cultivardependent manner over the developmental time-course. Additionally, read alignment-based variant calling revealed several short variants in differentially expressed genes, associated with enriched gene ontologies and associated metabolic processes, lending potential insight into the genetic basis for different abscission responses between the cultivars. These results provide genetic targets for the induction or inhibition of PFAZ activation, depending on the desire to harvest the fruit with or without the stem attached. Understanding the genetic mechanisms underlying the development of the PFAZ will inform future cultivar development while laying a foundation for mechanized sweet cherry harvest. [ABSTRACT FROM AUTHOR]

Green shoot thinning in vineyards is an essential, perennial operation for maintaining canopy health and optimizing yield and quality of wine grapes. Use of mechanized thinning system, which is essential to reduce labor dependency and associated cost, causes high variability in shoot removal efficiency due to difficulty in precisely positioning the thinning end‐effector along cordon trajectories. Automated/robotic solution for precise positioning of the thinning end‐effector could significantly improve the performance and efficiency of mechanical green shoot thinning. This study presents: (i) a machine vision‐based cordon detection system that can estimate cordon trajectories at different shoot growth stages in a vineyard; and (ii) evaluation of an integrated green shoot thinning system capable of automatically positioning the thinning end‐effector following vine cordon trajectories. The developed machine vision system uses deep learning‐based techniques that could accurately estimate cordon trajectories with root mean square error (RMSE) of 7.3, 10.3, and 16.1 pixels for canopy images captured in 2–4 weeks of shoot growth, respectively. Then, a control strategy was presented for the integrated system, which receives the computed cordon trajectories from machine vision system to automatically position the thinning end‐effector to cordon trajectories. Field evaluations in a research vineyard showed that the integrated system can achieve an RMSE of 1.47 cm in following the cordon trajectories at 6.6 cm·s−1 forward speed. Future work will incorporate additional sensing system to detect individual shoot on cordon and integrating it with an existing system to achieve higher level of precision in green shoot thinning. [ABSTRACT FROM AUTHOR]