Evaluating the Roles of Rainout and Post-Condensation Processes in a Landfalling Atmospheric River with Stable Isotopes in Precipitation and Water Vapor

Atmospheric rivers (ARs), and frontal systems more broadly, tend to exhibit prominent “V” shapes in time series of stable isotopes in precipitation. Despite the magnitude and widespread nature of these “V” shapes, debate persists as to whether these shifts are driven by changes in the degree of rainout, which we determine using the Rayleigh distillation of stable isotopes, or by post-condensation processes such as below-cloud evaporation and equilibrium isotope exchange between hydrometeors and surrounding vapor. Here, we present paired precipitation and water vapor isotope time series records from the 5–7 March 2016, AR in Bodega Bay, CA. The stable isotope composition of surface vapor along with independent meteorological constraints such as temperature and relative humidity reveal that rainout and post-condensation processes dominate during different portions of the event. We find that Rayleigh distillation controls during peak AR conditions (with peak rainout of 55%) while post-condensation processes have their greatest effect during periods of decreased precipitation on the margins of the event. These results and analyses inform critical questions regarding the temporal evolution of AR events and the physical processes that control them at local scales

Twisting 2-cocycles for the construction of new non-standard quantum groups

We introduce a new class of 2-cocycles defined explicitly on the generators of certain multiparameter standard quantum groups. These allow us, through the process of twisting the familiar standard quantum groups, to generate new as well as previously known examples of non-standard quantum groups. In particular we are able to construct generalisations of both the Cremmer-Gervais deformation of SL(3) and the so called esoteric quantum groups of Fronsdal and Galindo in an explicit and straightforward manner.Comment: 21 pages, AMSLaTeX, expanded introduction and a few other minor corrections, to appear in JM

Acute Effects of Passive Muscle Stretching on the Stretch-Shortening Phenomenon.

Two experiments examined the acute effects of passive muscle stretching on the performance of a skill (vertical jump) which takes advantage of the stretch-shortening phenomenon. Because recent work suggests that passive stretching might impede the mechanisms (elastic and myoelectrical potentiation) thought to be responsible for this phenomenon, it was hypothesized that stretching would decrease the jump height of jumps executed with a preparatory countermovement (CMJ), but not the jump height of those initiated from a static, squatting position (SJ). In the first experiment, subjects performed CMJ and SJ jumps under two different conditions: after passively stretching the knee and hip extensors, and after 10 minutes of quiet sitting. As predicted, stretching induced a significant decrease (p $\u3c$.05) in jump height for the CMJ; however, a similar decrease (p $\u3c$.05) also occurred for the SJ. These results suggest that the influence of acute stretching on performance is not limited to skills which incorporate a stretch-shortening cycle, and that stretching does not necessarily impede the factors purported to be responsible for the stretch-shortening phenomenon. Experiment 2 sought to explicate the reasons why an acute bout of passive stretching can negatively impact jumping performance. Specifically, the aim was to determine if stretching could modify musculotendinous stiffness and/or electrical activity of the plantar flexors during both stretch-shortening movements and movements involving purely concentric contractions. Again, jumps performed with a countermovement were compared to static jumps; however, in order to isolate the plantar flexors, motion was restricted to the ankle joint only. CMJ jump height was compromised after stretching but SJ performance remained unchanged. The decrease in CMJ performance might be partially accounted for by a reduction in elastic potentiation, because a decrease in musculotendinous stiffness was also observed post-stretching. No change in electrical activity occurred between the pre- and post-stretch conditions for the CMJ, suggesting that a decrease in myoelectrical potentiation did not contribute to the performance decrement. Other potential mechanisms which might have played a role in reducing performance are discussed in addition to possible reasons why the stretching treatment influenced SJ performance differently in the two experiments

Redox reactions and weak buffering capacity lead to acidification in the Chesapeake Bay

The combined effects of anthropogenic and biological CO2 inputs may lead to more rapid acidification in coastal waters compared to the open ocean. It is less clear, however, how redox reactions would contribute to acidification. Here we report estuarine acidification dynamics based on oxygen, hydrogen sulfide (H2S), pH, dissolved inorganic carbon and total alkalinity data from the Chesapeake Bay, where anthropogenic nutrient inputs have led to eutrophication, hypoxia and anoxia, and low pH. We show that a pH minimum occurs in mid-depths where acids are generated as a result of H2S oxidation in waters mixed upward from the anoxic depths. Our analyses also suggest a large synergistic effect from river-ocean mixing, global and local atmospheric CO2 uptake, and CO2 and acid production from respiration and other redox reactions. Together they lead to a poor acid buffering capacity, severe acidification and increased carbonate mineral dissolution in the USA\u27s largest estuary

Author correction : a global database for metacommunity ecology, integrating species, traits, environment and space

Correction to: Scientific Data https://doi.org/10.1038/s41597-019-0344-7, published online 08 January 202

GASKAP -- The Galactic ASKAP Survey

A survey of the Milky Way disk and the Magellanic System at the wavelengths of the 21-cm atomic hydrogen (HI) line and three 18-cm lines of the OH molecule will be carried out with the Australian Square Kilometre Array Pathfinder telescope. The survey will study the distribution of HI emission and absorption with unprecedented angular and velocity resolution, as well as molecular line thermal emission, absorption, and maser lines. The area to be covered includes the Galactic plane (|b|< 10deg) at all declinations south of delta = +40deg, spanning longitudes 167deg through 360deg to 79deg at b=0deg, plus the entire area of the Magellanic Stream and Clouds, a total of 13,020 square degrees. The brightness temperature sensitivity will be very good, typically sigma_T ~ 1 K at resolution 30arcsec and 1 km/s. The survey has a wide spectrum of scientific goals, from studies of galaxy evolution to star formation, with particular contributions to understanding stellar wind kinematics, the thermal phases of the interstellar medium, the interaction between gas in the disk and halo, and the dynamical and thermal states of gas at various positions along the Magellanic Stream.Comment: 45 pages, 8 figures, Pub. Astron. Soc. Australia (in press

Author correction : a global database for metacommunity ecology, integrating species, traits, environment and space

Correction to: Scientific Data https://doi.org/10.1038/s41597-019-0344-7, published online 08 January 202