Maintaining and Improving Irrigation Application Uniformity in Sprinkler and Drip Systems

The goal of most irrigation system design and management is to provide all plants in an irrigated area with equal access to water. Ideally, each plant should receive the exact amount of water it needs. If a field needs 1 inch of water for irrigation, all parts of the field should receive exactly that. The reality is not so perfect. It is practically impossible to apply the same quantity of water to all plants in an irrigated area, plot, or field. In other words, all irrigation systems have some nonuniformities in the water delivered. Instead of designing and managing irrigation systems to apply water 100% uniformly, the goal of irrigation system designers, manufacturers, and operators should be to maximize irrigation uniformity within practical and economic constraints. In this fact sheet, we explain the major causes of uneven water distribution in sprinkler and drip irrigation systems and suggest ways to improve or maintain uniformity

Offsetting of CO₂ emissions by air capture in mine tailings at the Mount Keith Nickel Mine, Western Australia: Rates, controls and prospects for carbon neutral mining

The hydrated Mg-carbonate mineral, hydromagnesite [Mg₅(CO₃)₄(OH)₂•4H₂O], precipitates within mine tailings at the Mount Keith Nickel Mine, Western Australia as a direct result of mining operations. We have used quantitative mineralogical data and δ¹³C, δ¹⁸O and F¹⁴C isotopic data to quantify the amount of CO₂fixation and identify carbon sources. Our radiocarbon results indicate that at least 80% of carbon stored in hydromagnesite has been captured from the modern atmosphere. Stable isotopic results indicate that dissolution of atmospheric CO₂ into mine tailings water is kinetically limited, which suggests that the current rate of carbon mineralization could be accelerated. Reactive transport modeling is used to describe the observed variation in tailings mineralogy and to estimate rates of CO₂ fixation. Based on our assessment, approximately 39,800 t/yr of atmospheric CO₂ are being trapped and stored in tailings at Mount Keith. This represents an offsetting of approximately 11% of the mine's annual greenhouse gas emissions. Thus, passive sequestration via enhanced weathering of mineral waste can capture and store a significant amount of CO₂. Recommendations are made for changes to tailings management and ore processing practices that have potential to accelerate carbonation of tailings and further reduce or completely offset the net greenhouse gas emissions at Mount Keith and many other mines

Unraveling Gender and Non-Accidental Violence in Women’s Gymnastics Research: A Critical Interpretive Synthesis

Non-accidental violence in women’s gymnastics has gained significant attention, and is a sport where gender is clearly differentiated. Despite the volume of gymnastics research on these themes it seemingly had little impact in preventing harm. We conducted a critical interpretative synthesis of 45 articles to reexamine the literature for understanding of, and connections between, gender and violence. We found that where gender viewed as a structure was explicit, violence was not. Conversely where violence was explicit, gender was implicit and viewed in individualist terms. Only one article explicitly connected gender and violence recognizing violence as a gendered outcome. We encourage researchers to incorporate gender as a structure in analytical inquiries and identify the wider contexts and associated mechanisms through which gender intersects with violence. Doing so can help to develop prevention measures that align with international definitions of gender-based violence

Temocillin: a new candidate antibiotic for local antimicrobial delivery in orthopaedic surgery?

Objectives - To assess the performance of the Gram-negative-specific antibiotic temocillin in polymethylmethacrylate bone cement pre-loaded with gentamicin, as a strategy for local antibiotic delivery. Methods - Temocillin was added at varying concentrations to commercial gentamicin-loaded bone cement. The elution of the antibiotic from cement samples over a 2 week period was quantified by LC-MS. The eluted temocillin was purified by fast protein liquid chromatography and the MICs for a number of antibiotic-resistant Escherichia coli were determined. The impact strength of antibiotic-loaded samples was determined using a Charpy-type impact testing apparatus. Results - LC-MS data showed temocillin eluted to clinically significant concentrations within 1 h in this laboratory system and the eluted temocillin retained antimicrobial activity against all organisms tested. Impact strength analysis showed no significant difference between cement samples with or without temocillin. Conclusions - Temocillin can be added to bone cement and retains its antimicrobial activity after elution. The addition of up to 10% temocillin did not affect the impact strength of the cement. The results show that temocillin is a promising candidate for use in antibiotic-loaded bone cement.</p

Building Pre-Service Teacher Capabilities through Remote and Flexible Placement - A New Narrative

Within practical placements, Australian pre-service teachers acquire a range of skills and strategies. This is in addition to linking the theory that they acquire at university to that in the classroom context. In 2020, to ensure that the pre-service teachers in education courses continue this practical component of their degree, remote and flexible placements were negotiated between the schools and the university. These changes were embedded in order for pre-service teachers to work with schools, students and mentors and they did so from within their homes. This chapter focuses on the experiences from three pre-service teachers during their time on practicum in remote and flexible contexts. A case study approach was applied to analyse each individual’s experiences. The case studies highlight the commonalities in experiences for each individual pre-service teacher. Upon analysis of these case studies, these commonalities included implications around how these capabilities were being formed and developed throughout the placement. These capabilities included inference, deduction, pivoting and empathy. These common capabilities across the pre-service teacher’s experiences, during their remote and flexible placement, highlight the need for a new narrative around the emerging skills, strategies and capabilities for teacher education in the 21st Century

Evolution of gaseous disk viscosity driven by supernova explosion. II. Structure and emissions from star-forming galaxies at high redshift

(Abridged) High redshift galaxies are undergoing intensive evolution of dynamical structure and morphologies. We incorporate the feedback into the dynamical equations through mass dropout and angular momentum transportation driven by the SNexp-excited turbulent viscosity. We numerically solve the equations and show that there can be intensive evolution of structure of the gaseous disk. Secular evolution of the disk shows interesting characteristics that are 1) high viscosity excited by SNexp can efficiently transport the gas from 10kpc to $\sim 1$kpc forming a stellar disk whereas a stellar ring forms for the case with low viscosity; 2) starbursts trigger SMBH activity with a lag $\sim 10^8$yr depending on star formation rates, prompting the joint evolution of SMBHs and bulges; 3) the velocity dispersion is as high as \sim 100~\kms in the gaseous disk. In order to compare the present models with the observed dynamical structure and images, we use the incident continuum from the simple stellar synthesis (GALAXEV) and CLOUDY to calculate emission line ratios of H$\alpha$, H$\beta$, \OIII and \NII, and H$\alpha$ brightness of gas photoionized by young massive stars formed on the disks. The models can produce the main features of emission from star forming galaxies and the observed relation between turbulent velocity and the H$\alpha$ brightness. We successfully apply the present model to BX 389 and BX 482 observed in SINS high$-z$ sample, which are bulge and disk-dominated, respectively. High viscosity excited by SNexp is able to efficiently transport the gas into a bulge to maintain high star formation rates, or, to form a stellar ring close enough to the bulge so that it immigrates into the bulge of its host galaxy. This leads to a fast growing bulge. Implications and future work of the present models have been extensively discussed for galaxy formation.Comment: Accepted by ApJ; 22 page in emulateapj, 16 color figure

Bridge distress caused by approach embankment settlement

Surtees Bridge, which carries the A66(T) over the River Tees near Thornaby-on-Tees in the UK, has been showing signs of distress that predate its opening in 1981. Subsequent investigations have shown that the bridge distress is related to unexpectedly large settlement of the eastern approach embankment. Recent ground investigations prompted by a proposed widening of the river crossing have produced many new data on the alluvial deposits underlying the site, and explain why embankment settlement was so much larger than originally anticipated. Comparison of the geotechnical parameters obtained from the original and more recent ground investigations suggests that the original investigation significantly underestimated the thickness of an alluvial clay layer underlying the site, and that its coefficient of consolidation was overestimated. Settlement analyses using geotechnical data from the original ground investigations predict moderate embankment settlements occurring principally during construction. Settlement analyses based on all the available data predict far larger embankment settlements occurring over extended time periods. The latter analyses predict an embankment settlement similar to that observed and of sufficient magnitude to cause the observed lateral displacement of the bridge due to lateral loading of its piled foundation

Silicate weathering and carbon cycle controls on the Oligocene-Miocene transition glaciation

Changes in both silicate weathering rates and organic carbon burial have been proposed as drivers of the transient “Mi-1” glaciation event at the Oligocene-Miocene transition (OMT; ~23 Ma). However detailed geochemical proxy data are required to test these hypotheses. Here we present records of Li/Ca, Mg/Ca, Cd/Ca, U/Ca, δ18O, δ13C, and shell weight in planktonic foraminifera from marine sediments spanning the OMT in the equatorial Atlantic Ocean. Li/Ca values increase by 1 μmol/mol across this interval. We interpret this to indicate a ~20% increase in silicate weathering rates, which would have lowered atmospheric CO2, potentially forcing the Antarctic glaciation circa 23 Ma. δ13C of thermocline dwelling planktonic foraminifera track the global increase in seawater δ13C across the OMT and during the Mi-1 event, hence supporting a hypothesized global increase in organic carbon burial rates. High δ13C previously measured in epipelagic planktonic foraminifera and high Cd/Ca ratios during Mi-1 are interpreted to represent locally enhanced primary productivity, stimulated by increased nutrients supply to surface waters. The fingerprint of high export production and associated organic carbon burial at this site is found in reduced bottom water oxygenation (inferred from high foraminiferal U/Ca), and enhanced respiratory dissolution of carbonates, characterised by reduced foraminiferal shell weight. Replication of our results elsewhere would strengthen the case that weathering-induced CO2 sequestration preconditioned climate for Antarctic ice sheet growth across the OMT and increased burial of organic carbon acted as a feedback that intensified cooling at this time

The Star Formation History in The Far Outer Disc of M33

The outer regions of disc galaxies are becoming increasingly recognized as key testing sites for models of disc assembly and evolution. Important issues are the epoch at which the bulk of the stars in these regions formed and how discs grow radially over time. To address these issues, we use Hubble Space Telescope Advanced Camera for Surveys imaging to study the star formation history (SFH) of two fields at 9.1 and 11.6 kpc along M33's northern major axis. These fields lie at ~ 4 and 5 V-band disc scale-lengths and straddle the break in M33's surface brightness profile. The colour-magnitude diagrams (CMDs) reach the ancient main sequence turnoff with a signal-to-noise ratio of ~ 5. From detailed modelling of the CMDs, we find that the majority of stars in both fields combined formed at z < 1. The mean age in the inner field, S1, is ~ 3 +/- 1 Gyr and the mean metallicity is [M/H] ~ -0.5 +/- 0.2 dex. The star formation history of S1 unambiguously reveals how the inside-out growth previously measured for M33's inner disc out to ~ 6 kpc extends out to the disc edge at ~ 9 kpc. In comparison, the outer field, S2, is older (mean age ~ 7 +/- 2 Gyr), more metal-poor (mean [M/H] ~ -0.8 +/- 0.3 dex), and contains ~ 30 times less stellar mass. These results provide the most compelling evidence yet that M33's age gradient reverses at large radii near the disc break and that this reversal is accompanied by a break in stellar mass surface density. We discuss several possible interpretations of this behaviour including radial stellar mixing, warping of the gaseous disc, a change in star formation efficiency, and a transition to another structural component. These results offer one of the most detailed views yet of the peripheral regions of any disc galaxy and provide a much-needed observational constraint on the last major epoch of star formation in the outer disc.Comment: 15 pages, 9 figures, accepted to MNRAS, hi-res version available at http://www.roe.ac.uk/~mkb/astroph/m33hires.pd

Magnetic phases of skyrmion-hosting GaV4S8−ySey (y = 0, 2, 4, 8) probed with muon spectroscopy

We present the results of a muon-spin spectroscopy investigation of GaV4S8−ySey with y = 0, 2, 4, and 8. Zero-field measurements suggest that GaV4Se8 and GaV4S8 have distinct magnetic ground states, with the latter material showing an anomalous temperature dependence of the local magnetic field. It is not possible to evolve the magnetic state continuously between these two systems, with the intermediate y = 2 and 4 materials showing glassy magnetic behavior at low temperature. The skyrmion lattice (SkL) phase is evident in the y = 0 and 8 materials through an enhanced response of the muon-spin relaxation to the emergent dynamics that accompany the SkL. For our polycrystalline samples of GaV4Se8, this enhanced dynamic response is confined to a smaller region of the magnetic field-temperature phase diagram than the previous reports of the SkL in single crystals