A comprehensive understanding of carbon-carbon bond formation by alkyne migratory insertion into manganacycles

Migratory insertion (MI) is one of the most important processes underpinning the transition metal-catalysed formation of C-C and C-X bonds. In this work, a comprehensive model of MI is presented, based on the direct observation of the states involved in the coupling of alkynes with cyclometallated ligands, augmented with insight from computational chemistry. Time-resolved spectroscopy demonstrates that photolysis of complexes [Mn(C^N)(CO)4] (C^N = cyclometalated ligand) results in ultra-fast dissociation of a CO ligand. Performing the experiment in a toluene solution of an alkyne results in the initial formation of a solvent complex fac-[Mn(C^N)(toluene)(CO)3]. Solvent substitution gives an η2-alkyne complex fac-[Mn(C^N)(η2-R1C2R2)(CO)3] which undergoes MI of the unsaturated ligand into the Mn-C bond. These data allowed for the dependence of second order rate constants for solvent substitution and first order rate constants for C-C bond formation to be determined. A systematic investigation into the influence of the alkyne and C^N ligand on this process is reported. The experimental data enabled the development of a computational model for the MI reaction which demonstrated that a synergic interaction between the metal and the nascent C-C bond controls both the rate and regiochemical outcome of the reaction. The time-resolved spectroscopic method enabled the observation of a multi-step reaction occurring over 8 orders of magnitude in time, including the formation of solvent complexes, ligand substitution and two sequential C-C bond formation steps

Wind erosion in Hawke's Bay : the influence of soil aggregate size and cultivation management on sediment flux : a thesis presented in partial fulfilment of the requirements for the degree of Masters of Applied Science (Natural Resource Management) at Massey University

The influence of soil aggregate size and cultivation management on sediment flux of two Hawke's Bay soils was investigated. Hawke's Bay Regional Council initiated, and partially funded, the project after they identified wind erosion as a significant land management issue in their region. Wind erosion was simulated on Pakipaki sandy loam (Typic Sandy Recent Soil) and Takapau silt loam (Typic Orthic Allophanic Soil) soil types using a portable wind tunnel. Three different cultivation treatments were applied to research sites on each soil, with eight replicates of each treatment positioned via a split-plot, randomised block trial design. Treatments were designed to produce a range of soil aggregate size distributions. A minimum tillage treatment was also simulated. At each plot, surface (10 mm depth) soil samples were collected for gravimetric moisture content, soil aggregate size and aggregate stability tests. Surface roughness and vegetative cover were measured only on Takapau plots. The Takapau silt loam plots were very susceptible to aggregate breakdown under cultivation, with only a quarter of soil aggregates over 0.85 mm in size after one pass with the cultivator. Two additional passes did not cause a significant change in aggregate size. Minimum tillage on the Takapau plots lead to markedly lower mean sediment flux rates (0.2 gm -1s-1) compared to one pass with a cultivator (3.4 gm-1s-1). The Pakipaki sandy loam exhibited higher resistance to aggregate breakdown compared to Takapau silt loam. After one pass of the cultivator 50 percent of aggregates measured were over 0.85 mm in size, reducing to 45 and 43.3 percent after two and three passes respectively. Data collected from Pakipaki plots suggest decreasing soil aggregate size leads to increasing erosion rates. The relationship was not significant (P<0.05) primarily due to a high variance in results within treatments. Minimum tillage on the Pakipaki sandy loam also resulted in considerably lower mean sediment flux (0.03 gm-1s-1) than the least cultivated plots (1.8 gm-1s-1). The results highlighted some important implications for cultivation management in Hawke's Bay. Use of conventional cultivation techniques on Takapau silt loam soils should be avoided due to the high risk of aggregate breakdown and the subsequent wind erosion risk. Minimum or no-tillage with maximum retention of vegetative residue is the most appropriate for continued arable farming on such soils. In comparison, soil structural characteristics of the Pakipaki sandy loam soil allow for greater manipulation of aggregate size through cultivation However, the sediment flux measured off Pakipaki plots indicates other wind erosion control techniques, such as windbreaks and stubble retention, should be utilised in conjunction w ith maintenance of large aggregate size to adequately control soil wind erosion

Learning and adaption challenges faced by livestock farmers using precision technologies

The use of information technology for aiding management of Australian livestock is increasing. However a gap exists between the potential perceived by technology developers and the on-farm benefits achieved by farmers in practice. In this paper the learning and farm system adaptation challenges faced by farmers using precision technologies in three livestock industry case studies are outlined

Muddied Waters: Estimating the national economic cost of soil erosion and sedimentation in New Zealand

Soil erosion research in New Zealand has focused on the on-site costs of soil loss in the form of production loss and storm damage. Subsidization and implementation of soil conservation measures have primarily been justified through maintenance or improvement of farm productivity levels. The shift in responsibility for soil conservation management and damage remedies from national to regional government has highlighted public good issues raised by soil erosion. This paper develops an inventory and assessment of the relative magnitude of the impacts of soil erosion and sedimentation in New Zealand. It also provides an estimate of the total economic costs of these impacts based on the limited data available. The impacts of greatest economic significance are highlighted, as are impacts that may be significant but for which data is limited. The implications for current and potential policy strategies are briefly discussed. The approach demonstrates the degree to which policy in this area is based on incomplete information. The nature and scale of the costs involved have implications for the relative efficiency of regional rather than national approaches to addressing this issue

A call to expand disciplinary boundaries so that social scientific imagination and practice are central to quests for ‘responsible’ digital agri-food innovation

This editorial introduces a special issue (SI) concerning quests for responsible digital agri-food innovation. We present our interpretations of the concepts of responsible innovation and digital agri-food innovation and show why they can and have been productively interrelated with social science theories and methods. First, each of the articles in this SI is briefly introduced and synthesised around three themes: (1) the need for a critique of digital ‘solutionism’ in current interdisciplinary research, development and innovation settings; (2) that social science contributes value via the ideas it brings to life to challenge dominant power dynamics and (3) that social scientific imagination and practice is a valuable long-term investment to both mitigate risk but also embrace socioenvironmental opportunities as we face ongoing sustainability crises into the future. Second, we identify future research considerations arising within the field, sitting at the intersection of social science and agricultural sociotechnical transitions. Our insights relate to challenges and opportunities to ‘do’ social science within the context of contemporary and nascent transitions such as increasing digitalisation. Researchers trained in social science theory and practice can make distinctive contributions to agri-food innovation processes by making social stakes visible and by advancing inclusive processes of research policy and technology design

2022 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations: Summary From the Basic Life Support; Advanced Life Support; Pediatric Life Support; Neonatal Life Support; Education, Implementation, and Teams; and First Aid Task Forces

This is the sixth annual summary of the International Liaison Committee on Resuscitation International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations. This summary addresses the most recently published resuscitation evidence reviewed by International Liaison Committee on Resuscitation Task Force science experts. Topics covered by systematic reviews include cardiopulmonary resuscitation during transport; approach to resuscitation after drowning; passive ventilation; minimizing pauses during cardiopulmonary resuscitation; temperature management after cardiac arrest; use of diagnostic point-of-care ultrasound during cardiac arrest; use of vasopressin and corticosteroids during cardiac arrest; coronary angiography after cardiac arrest; public-access defibrillation devices for children; pediatric early warning systems; maintaining normal temperature immediately after birth; suctioning of amniotic fluid at birth; tactile stimulation for resuscitation immediately after birth; use of continuous positive airway pressure for respiratory distress at term birth; respiratory and heart rate monitoring in the delivery room; supraglottic airway use in neonates; prearrest prediction of in-hospital cardiac arrest mortality; basic life support training for likely rescuers of high-risk populations; effect of resuscitation team training; blended learning for life support training; training and recertification for resuscitation instructors; and recovery position for maintenance of breathing and prevention of cardiac arrest. Members from 6 task forces have assessed, discussed, and debated the quality of the evidence using Grading of Recommendations Assessment, Development, and Evaluation criteria and generated consensus treatment recommendations. Insights into the deliberations of the task forces are provided in the Justification and Evidence-to-Decision Framework Highlights sections, and priority knowledge gaps for future research are listed.</jats:p

A Bayesian reanalysis of the Standard versus Accelerated Initiation of Renal-Replacement Therapy in Acute Kidney Injury (STARRT-AKI) trial

Background Timing of initiation of kidney-replacement therapy (KRT) in critically ill patients remains controversial. The Standard versus Accelerated Initiation of Renal-Replacement Therapy in Acute Kidney Injury (STARRT-AKI) trial compared two strategies of KRT initiation (accelerated versus standard) in critically ill patients with acute kidney injury and found neutral results for 90-day all-cause mortality. Probabilistic exploration of the trial endpoints may enable greater understanding of the trial findings. We aimed to perform a reanalysis using a Bayesian framework. Methods We performed a secondary analysis of all 2927 patients randomized in multi-national STARRT-AKI trial, performed at 168 centers in 15 countries. The primary endpoint, 90-day all-cause mortality, was evaluated using hierarchical Bayesian logistic regression. A spectrum of priors includes optimistic, neutral, and pessimistic priors, along with priors informed from earlier clinical trials. Secondary endpoints (KRT-free days and hospital-free days) were assessed using zero–one inflated beta regression. Results The posterior probability of benefit comparing an accelerated versus a standard KRT initiation strategy for the primary endpoint suggested no important difference, regardless of the prior used (absolute difference of 0.13% [95% credible interval [CrI] − 3.30%; 3.40%], − 0.39% [95% CrI − 3.46%; 3.00%], and 0.64% [95% CrI − 2.53%; 3.88%] for neutral, optimistic, and pessimistic priors, respectively). There was a very low probability that the effect size was equal or larger than a consensus-defined minimal clinically important difference. Patients allocated to the accelerated strategy had a lower number of KRT-free days (median absolute difference of − 3.55 days [95% CrI − 6.38; − 0.48]), with a probability that the accelerated strategy was associated with more KRT-free days of 0.008. Hospital-free days were similar between strategies, with the accelerated strategy having a median absolute difference of 0.48 more hospital-free days (95% CrI − 1.87; 2.72) compared with the standard strategy and the probability that the accelerated strategy had more hospital-free days was 0.66. Conclusions In a Bayesian reanalysis of the STARRT-AKI trial, we found very low probability that an accelerated strategy has clinically important benefits compared with the standard strategy. Patients receiving the accelerated strategy probably have fewer days alive and KRT-free. These findings do not support the adoption of an accelerated strategy of KRT initiation