Energy,Nitrogen, and Farm Surplus Transitions in Agriculture from Historical Data Modeling. France, 1882–2013.

This article addresses agricultural metabolism and transitions for energy, nitrogen, farm production, self‐sufficiency, and surplus from historical data since the nineteenth century. It builds on an empirical data set on agricultural production and production means in France covering 130 consecutive years (1882–2013). Agricultural transitions have increased the net production and surplus of farms by a factor of 4 and have zeroed self‐sufficiency. The energy consumption remained quasi‐stable since 1882, but the energy and nitrogen structure of agriculture fully changed. With an EROI (energy return to energy invested) of 2 until 1950, preindustrial agriculture consumed as much energy to function as it provided in exportable surplus to sustain the nonagricultural population. The EROI doubled to 4 over the last 60 years, driven, on the one hand, by efficiency improvements in traction through the replacement of draft animals by motors and, on the other hand, by the joint increase in crop yields and efficiency in nitrogen use. Agricultural energy and nitrogen transitions shifted France from a self‐sufficiency agri‐food‐energy regime to a fossil‐dependent food export regime. Knowledge of resource conversion mechanisms over the long duration highlights the effects of changing agricultural metabolism on the system's feeding capacity. Farm self‐sufficiency is an asset against fossil fuel constraints, price volatility, and greenhouse gas emissions, but it equates to lower farm surplus in support of urbanization.     

Stopping or maintaining oral anticoagulation in patients undergoing photoselective vaporization of the prostate (SOAP) surgery for benign prostate obstruction: study protocol for a multicentre randomized controlled trial

Background

Lower urinary tract symptoms related to benign prostatic obstruction (BPO) are frequent in men aged >?50?years. Based on the use of innovative medical devices, a number of transurethral ablative techniques have recently been developed for the surgical treatment of BPO. In recent years, GreenLight photoselective vaporization of the prostate (PVP) has been considered as a non-inferior alternative to transurethral resection of the prostate. The GreenLight PVP is usually considered as an interesting surgical option for patients treated via oral anticoagulants (OACs) with regard to its haemostatic properties. The aim of this study was to assess the impact of maintaining OAC treatment in patients undergoing PVP.

Methods

This study is a multicentre, open-label, randomized controlled trial (RCT) designed to show the non-inferiority of PVP surgery in patients with BPO treated with OACs. This study is designed to enrol 386 OAC-treated patients (treated with vitamin K antagonists and direct oral anticoagulants) who are undergoing PVP for BPO. Patients will be randomized (1:1) to either maintain or stop OAC treatment during the perioperative course. The intervention group will maintain OAC treatment until the day before surgery and resume OAC treatment the day after surgery, whereas the control group will stop OAC treatment (with or without low-molecular-weight heparin bridging therapy) according to the anaesthesia guidelines. The primary outcome of interest to be assessed is the 30-day complications rate according to the Clavien-Dindo classification. The secondary endpoint will examine the 30-day rate of haemorrhagic and thrombotic events. This study will provide 80% power to show non-inferiority, defined as not worse than a 10% (non-inferiority margin) inferior change in the proportion of patients with good outcomes (Clavien-Dindo score?<?2), using two-tailed 95% confidence intervals.

Discussion

This first multicentre RCT in the field is underway to evaluate the safety and efficacy of PVP in patients with ongoing OAC therapy. The study results could influence the perioperative management of OACs in BPO surgery with a high level of evidence.

Trial registration

ClinicalTrials.gov, NCT03297281. Registered on 29 September 2017.