Over the last 25 years, radiowave detection of neutrino-generated signals, using cold polar ice as the neutrino target, has emerged as perhaps the most promising technique for detection of extragalactic ultra-high energy neutrinos (corresponding to neutrino energies in excess of 0.01 Joules, or 1017 electron volts). During the summer of 2021 and in tandem with the initial deployment of the Radio Neutrino Observatory in Greenland (RNO-G), we conducted radioglaciological measurements at Summit Station, Greenland to refine our understanding of the ice target. We report the result of one such measurement, the radio-frequency electric field attenuation length $L_\alpha$. We find an approximately linear dependence of $L_\alpha$ on frequency with the best fit of the average field attenuation for the upper 1500 m of ice: $\langle L_\alpha \rangle = ( ( 1154 \pm 121) - ( 0.81 \pm 0.14) \, ( \nu /{\rm MHz}) ) \,{\rm m}$ for frequencies ν ∈ [145 − 350] MHz.

Previous research has shown that glufosinate and nicosulfuron at low rates can cause yield loss to grain sorghum. However, research has not been conducted to pinpoint the growth stage at which these herbicides are most injurious to grain sorghum. Therefore, field tests were conducted in 2016 and 2017 to determine the most sensitive growth stage for grain sorghum exposure to both glufosinate and nicosulfuron. Field test were designed with factor A being the herbicide applied (glufosinate or nicosulfuron). Factor B consisted of timing of herbicide application including V3, V8, flagleaf, heading, and soft dough stages. Factor C was glufosinate or nicosulfuron rate where a proportional rate of 656 g ai ha−1 of glufosinate and 35 g ai ha−1 of nicosulfuron was applied at 1/10×, 1/50×, and 1/250×. Visible injury, crop canopy heights (cm), and yield were reported as a percent of the nontreated. At the V3 growth stage visible injury of 32% from the 1/10× rate of glufosinate and 51% from the 1/10× rate of nicosulfuron was observed. This injury was reduced by 4 wk after application (WAA) and no yield loss occurred. Nicosulfuron was more injurious than glufosinate at a 1/10× and 1/50× rate when applied at the V8 and flagleaf growth stages resulting in death of the shoot, reduced heading, and yield. Yield losses from the 1/10× rate of nicosulfuron were observed from V8 through early heading and ranged from 41% to 96%. Yield losses from the 1/50× rate of nicosulfuron were 14% to 16% at the flagleaf and V8 growth stages respectively. The 1/10× rate of glufosinate caused 36% visible injury 2 WAA when applied at the flagleaf stage, which resulted in a 16% yield reduction. By 4 WAA visible injury from either herbicide at less than the 1/10× rate was not greater than 4%. Results indicate that injury can occur, but yield losses are more probable from low rates of nicosulfuron at V8 and flagleaf growth stages.

A non-GMO trait called Inzen™ was recently commercialized in grain sorghum to combat weedy grasses, allowing the use of nicosulfuron POST in the crop. Inzen™ grain sorghum carries a double mutation in the acetolactate synthase (ALS) gene Val560Ile and Trp574Leu, which potentially results in cross-resistance to a wide assortment of ALS-inhibiting herbicides. To evaluate the scope of cross-resistance to Weed Science Society of America Group 2 herbicides in addition to nicosulfuron, tests were conducted in 2016 and 2017 at the Lon Mann Cotton Research Station near Marianna, AR, the Arkansas Agricultural Research and Extension Center in Fayetteville, AR, and in 2016 at the Pine Tree Research Station near Colt, AR. The tests included ALS-inhibiting herbicides from all five families: sulfonylureas, imidazolinones, pyrimidinylthiobenzoics, triazolinones, and triazolopyrimidines. Treatments were made PRE or POST to grain sorghum at a 1× rate for crops in which each herbicide is labeled. Grain sorghum planted in the PRE trial were Inzen™ and a conventional cultivar. Visible estimates of injury and sorghum heights were recorded at 2 and 4 wk after herbicide application, and yield data were collected at crop maturity. In the PRE trial, no visible injury, sorghum height reduction, or yield loss were observed in plots containing the Inzen™ cultivar. Applications made POST to the Inzen™ grain sorghum caused visible injury, sorghum height reduction, and yield loss of 20%, 13%, and 35%, respectively, only in plots where bispyribac-Na was applied. There was no impact on the crop from other POST-applied ALS-inhibiting herbicides. These results demonstrate that the Inzen™ trait confers cross-resistance to most ALS-inhibiting herbicides and could offer promising new alternatives for weed control and protection from carryover of residual ALS-inhibiting herbicides in grain sorghum.

The Square Kilometre Array (SKA) is a planned large radio interferometer designed to operate over a wide range of frequencies, and with an order of magnitude greater sensitivity and survey speed than any current radio telescope. The SKA will address many important topics in astronomy, ranging from planet formation to distant galaxies. However, in this work, we consider the perspective of the SKA as a facility for studying physics. We review four areas in which the SKA is expected to make major contributions to our understanding of fundamental physics: cosmic dawn and reionisation; gravity and gravitational radiation; cosmology and dark energy; and dark matter and astroparticle physics. These discussions demonstrate that the SKA will be a spectacular physics machine, which will provide many new breakthroughs and novel insights on matter, energy, and spacetime.

The anti-inflammatory mechanisms of low-fat dairy product consumption are largely unknown. The objective of this study was to determine whether low-fat yogurt reduces biomarkers of chronic inflammation and endotoxin exposure in women. Premenopausal women (BMI 18·5–27 and 30–40 kg/m2) were randomised to consume 339 g of low-fat yogurt (yogurt non-obese (YN); yogurt obese (YO)) or 324 g of soya pudding (control non-obese; control obese (CO)) daily for 9 weeks (n 30/group). Fasting blood samples were analysed for IL-6, TNF-α/soluble TNF II (sTNF-RII), high-sensitivity C-reactive protein, 2-arachidonoyl glycerol, anandamide, monocyte gene expression, soluble CD14 (sCD14), lipopolysaccharide (LPS), LPS binding protein (LBP), IgM endotoxin-core antibody (IgM EndoCAb), and zonulin. BMI, waist circumference and blood pressure were also determined. After 9-week yogurt consumption, YO and YN had decreased TNF-α/sTNFR-RII. Yogurt consumption increased plasma IgM EndoCAb regardless of obesity status. sCD14 was not affected by diet, but LBP/sCD14 was lowered by yogurt consumption in both YN and YO. Yogurt intervention increased plasma 2-arachidonoylglycerol in YO but not YN. YO peripheral blood mononuclear cells expression of NF-κB inhibitor α and transforming growth factor β1 increased relative to CO at 9 weeks. Other biomarkers were unchanged by diet. CO and YO gained approximately 0·9 kg in body weight. YO had 3·6 % lower diastolic blood pressure at week 3. Low-fat yogurt for 9 weeks reduced biomarkers of chronic inflammation and endotoxin exposure in premenopausal women compared with a non-dairy control food. This trial was registered as NCT01686204.

The phenotype of the human embryo conceived through in vitro fertilization (IVF), that is its morphology, developmental kinetics, physiology and metabolism, can be affected by numerous components of the laboratory and embryo culture system (which comprise the laboratory environment). The culture media formulation is important in determining embryo phenotype, but this exists within a culture system that includes oxygen, temperature, pH and whether an embryo is cultured individually or in a group, all of which can influence embryo development. Significantly, exposure of an embryo to one suboptimal component of the culture system of laboratory typically predisposes the embryo to become more vulnerable to a second stressor, as has been well documented for atmospheric oxygen and individual culture, as well as for oxygen and ammonium. Furthermore, the inherent viability of the human embryo is derived from the quality of the gametes from which it is created. Patient age, aetiology, genetics, lifestyle (as well as ovarian stimulation in women) are all known to affect the developmental potential of gametes and hence the embryo. Thus, as well as considering the impact of the IVF laboratory environment, one needs to be aware of the status of the infertile couple, as this impacts how their gametes and embryos will respond to an in vitro environment. Although far from straight forward, analysing the interactions that exist between the human embryo and its environment will facilitate the creation of more effective and safer treatments for the infertile couple.

We report the observation of two isolated clouds of positrons inside an active thunderstorm. These observations were made by the Airborne Detector for Energetic Lightning Emissions (ADELE), an array of six gamma-ray detectors, which flew on a Gulfstream V jet aircraft through the top of an active thunderstorm in August 2009. ADELE recorded two 511 keV gamma-ray count rate enhancements, 35 s apart, each lasting approximately 0.2 s. The enhancements, which were approximately a factor of 12 above background, were both accompanied by electrical activity as measured by a flat-plate antenna on the underside of the aircraft. The energy spectra were consistent with a source mostly composed of positron annihilation gamma rays, with a prominent 511 keV line clearly visible in the data. Model fits to the data suggest that the aircraft was briefly immersed in clouds of positrons, more than a kilometre across. It is not clear how the positron clouds were created within the thunderstorm, but it is possible they were caused by the presence of the aircraft in the electrified environment.

Successful management of downy brome (also known as cheatgrass) requires understanding land managers' perceptions and decisions about whether to invest in its control. We investigated ranchers' and natural resource professionals' (NRPs) perceptions and knowledge about downy brome ecology and its impacts, their current downy brome management practices and satisfaction with those practices, and their information and technical needs using focus groups and a mail survey of ranchers and NRPs in Colorado and Wyoming. Both groups thought downy brome was a problem, and perception of the severity of downy brome corresponded to the level of infestation in the respondent's region. NRPs identified downy brome as a bigger problem than did ranchers from the same area in all but one region. Ranchers were most likely to use early spring grazing to control downy brome, and NRPs were most likely to use seeding, imazapic herbicide, or a combination of methods. Both groups reported that the primary constraint to controlling downy brome was that other weeds were a higher priority. Ranchers and NRPs wanted more information about the control methods they were already likely to use as well as other downy brome control methods. Our findings suggest that (1) listing a species as a noxious weed may provide an important incentive to control it, but trade-offs among control efforts for different species must be carefully considered; (2) managers need to know more about low-cost, low-labor strategies for managing downy brome; and (3) some managers need to be informed about how to identify downy brome, its potential negative effects, and how to prevent its spread. Better quantification of the economic and ecological impacts of downy brome in the Central Rocky Mountains, continued development of effective and economically viable management methods, and improvement in the dissemination of that information to land managers are necessary for successful control of downy brome.

Extended abstract of a paper presented at Microscopy and Microanalysis 2013 in Indianapolis, Indiana, USA, August 4 – August 8, 2013.

The propagation of a premixed flame inside of a confining vessel filled with combustible fluid is determined using large-activation-energy asymptotics. The flame structure is analysed assuming that spatial and temporal variations in the transverse direction are weak compared to those in the direction normal to the flame surface. The analysis considers weak pressure rise from confinement and also allows for mixtures that are both near and removed from stoichiometry, non-unity reaction orders, temperature-dependent transport coefficients, and general Lewis numbers. The resulting equations for flame propagation speed are expressed in a coordinate-free form and describe the evolution of an arbitrary shaped flame in a general confining flow. These expressions are specifically applied to the case of a spherical flame propagating inside a spherical chamber. The radius at which the confining vessel influences the flame propagation is determined and the various mechanisms influencing flame behaviour are discussed. The results give rise to a simplified asymptotic relationship that provides an improved equation that may be used to more accurately extrapolate unstretched laminar flame speeds from experimental measurements.