The Future of Clovers in Forage Systems and as Cover Crops

Clovers (Trifolium spp.) are the most widely used genera of legumes in forage systems, although only a limited number of the hundreds of perennial and annual species are commercially available. The number of varieties available within each of the main commercial species can be high and demonstrates past breeding achievements. Success relates to any clover’s ability to persist in mixtures with other forage species, across a range of soil types, management systems, and climates, while providing animal nutrition and biologically fixed nitrogen benefits. Uses range from traditional pasture mixtures with grasses to inclusion in multi-species mixtures, and as cover crop mixes as part of annual cropping systems. Both conventional breeding and genetic modification will lead to better adapted and performing varieties as well as new traits that provide additional benefits for improved animal nutrition and environmental outcomes. The use of genotyping by sequencing (GBS) to determine genetic variation and population structure for clover improvement programs shows great promise. Selection for improved seed yields while maintaining good agronomic performance will ensure cost effective seed production of commercial varieties. Seed coating with effective rhizobia is paramount for nitrogen fixation benefits to be realised. Management systems research to increase the use and economics of clover varieties in future pasture, cover crop, and carbon farming sustainability systems is critical but challenging

The impact of energy price changes in Moldova

In January 2006 the price of natural gas supplied to Moldova increased from $80 to$110 per thousand cubic meters (mcm). Prices may increase further in the near future, putting additional pressure on the economy and leading to adverse effects on the poorest households. This study examines the potential impact of higher energy prices on the economy of Moldova by simulating the likely macroeconomic consequences of recent and future price increases. Moreover, it estimates the direct impact on individual households using data drawn from the 2004 Household Budget Survey. It assesses the distributional implications of the price shock, noting how the social impact may vary depending on the intensity of energy use, geographic location, and the relative share of energy in household expenditure. The results suggest that energy price changes could dampen economic growth while putting additional strains on the current account deficit. The impact on the poorest households could be significant and protecting them may require resources in the amount of 0.7 to 1.7 percent of GDP. This study identifies possible policy responses to dampen the shock of the energy price increase and to promote the longer-term objective of reducing energy vulnerability.Energy Production and Transportation,Environment and Energy Efficiency,Energy and Environment,Markets and Market Access,Transport and Environment

Fast production of Bose-Einstein condensates of metastable Helium

We report on the Bose-Einstein condensation of metastable Helium-4 atoms using a hybrid approach, consisting of a magnetic quadrupole and a crossed optical dipole trap. In our setup we cross the phase transition with 2x10^6 atoms, and we obtain pure condensates of 5x10^5 atoms in the optical trap. This novel approach to cooling Helium-4 provides enhanced cycle stability, large optical access to the atoms and results in production of a condensate every 6 seconds - a factor 3 faster than the state-of-the-art. This speed-up will dramatically reduce the data acquisition time needed for the measurement of many particle correlations, made possible by the ability of metastable Helium to be detected individually

Verifying Safety Properties With the TLA+ Proof System

TLAPS, the TLA+ proof system, is a platform for the development and mechanical verification of TLA+ proofs written in a declarative style requiring little background beyond elementary mathematics. The language supports hierarchical and non-linear proof construction and verification, and it is independent of any verification tool or strategy. A Proof Manager uses backend verifiers such as theorem provers, proof assistants, SMT solvers, and decision procedures to check TLA+ proofs. This paper documents the first public release of TLAPS, distributed with a BSD-like license. It handles almost all the non-temporal part of TLA+ as well as the temporal reasoning needed to prove standard safety properties, in particular invariance and step simulation, but not liveness properties

Off-road mobile robot control: An adaptive approach for accuracy and integrity

International audienceThis paper proposes an algorithm dedicated to the control of off-road mobile robots at high speed. Based on adaptive and predictive principles, it first proposes a control law to preserve a high level of accuracy in the path tracking problem. Next, the dynamic model used for grip condition estimation is considered to address also robot integrity preservation thanks to the velocity limitation

Use of the Grazing Animal in Forage Breeding

The objective of these studies was to determine, in the context of a forage breeding program, the effect of cattle grazing on survival of alfalfa (Medicago sativa L.), red clover (Trifolium pratense L.), and tall fescue (Festuca arundinacea Schreb.). Different cultivars of each species were compared in grazed and ungrazed areas. Results consistently demonstrated that grazing reduced plant stands when compared to ungrazed conditions for each species tested. In alfalfa, however, cultivars developed for grazing tolerance showed much better grazing survival. Infection with the fungal endophyte, Acremonium coenophialum Morgan-Jones & Gams, likewise substantially increased grazing survival in tall fescue. These experiments further demonstrate that cultivar selection and testing needs to be accomplished with the grazing animal to properly assess pasture potential. Selection from elite germplasm under these conditions should probably be practiced as early as possible in the breeding program for species with poor pasture persistence

Rats distinguish between absence of events and lack of evidence in contingency learning.

The goal of three experiments was to study whether rats are aware of the difference between absence of events and lack of evidence. We used a Pavlovian extinction paradigm in which lights consistently signaling sucrose were suddenly paired with the absence of sucrose. The crucial manipulation involved the absent outcomes in the extinction phase. Whereas in the Cover conditions, access to the drinking receptacle was blocked by a metal plate, in the No Cover conditions, the drinking receptacle was accessible. The Test phase showed that in the Cover conditions, the measured expectancies of sucrose were clearly at a higher level than in the No Cover conditions. We compare two competing theories potentially explaining the findings. A cognitive theory interprets the observed effect as evidence that the rats were able to understand that the cover blocked informational access to the outcome information, and therefore the changed learning input did not necessarily signify a change of the underlying contingency in the world. An alternative associationist account, renewal theory, might instead explain the relative sparing of extinction in the Cover condition as a consequence of context change. We discuss the merits of both theories as accounts of our data and conclude that the cognitive explanation is in this case preferred

New active safety device dedicated to light all-terrain vehicle stability: Application to quad bike and off-road mobile robot

International audienceAccording to their specific geometric and dynamic characteristics (small weight, huge reachable speeds ), All-Terrain Vehicles (ATVs - as quad bikes) and off-road mobile robots are very compact and driveable. They permit to realize extra agricultural tasks (spreading, spraying ) in an easier way than using once more a heavy farm tractor. However such vehicles require highly accurate control laws, able to preserve their stability even at high speed. In this paper, the prevention of off-road vehicle and mobile robot rollover are addressed by using a new active safety device. It consists in using Predictive Functional Control (PFC) so as to compute, on-line, the maximum vehicle velocity, compatible with a safe motion over some horizon of prediction, and can be applied, if needed, to the vehicle actuator to prevent from rollover. The capabilities of the proposed device are demonstrated and discussed thanks to both advanced simulations and real experimentation