Organic dairy farming in Norway under the 100% organically produced feed requirement

The EU regulation governing organic production will require 100% organic feed in organic dairy systems from August 2005 compared with 85% currently in Norway. This study aimed to assess adjustments in resource use and financial impacts on organic dairy herds using a discrete stochastic programming model. Farm management effects of the regulatory change varied between farm types. For the two organic dairy systems examined, both having a milk quota of 100 000 litres but with varying farmland availability, the introduction of the 100% organic feed regulation resulted in an economic loss of approximately 6-8% of the net income compared to the current regime. The economic loss was mainly due to the considerable higher price of organic compared to conventional concentrates

Stochastic utility-efficient programming of organic dairy farms

Opportunities to make sequential decisions and adjust activities as a season progresses and more information becomes available characterise the farm management process. In this paper, we present a discrete stochastic two-stage utility efficient programming model of organic dairy farms, which includes risk aversion in the decision maker’s objective function as well as both embedded risk (stochastic programming with recourse) and non-embedded risk (stochastic programming without recourse). Historical farm accountancy data and subjective judgements were combined to assess the nature of the uncertainty that affects the possible consequences of the decisions. The programming model was used within a stochastic dominance framework to examine optimal strategies in organic dairy systems in Norway

Economic sustainability and risk efficiency of organic versus conventional cropping systems

Environmental, social and economic attributes are important for the sustainability of a farming system. Resilience is also important yet has seldom been directly considered in evaluations of economic sustainability. In economic terms, resilience has to do with the capacity of the farm business to survive various risks and other shocks. A whole-farm stochastic simulation model over a six-year planning horizon was used to analyse organic and conventional cropping systems using a model of a representative farm in Eastern Norway. The relative economic sustainability of alternative systems under changing assumptions about future technology and price regimes was examined in terms of financial survival to the end of the planning period. The same alternatives were also compared in terms of stochastic efficiency. The results illustrate possible confl icts between pursuit of risk efficiency and sustainability. The model developed could be useful in supporting farmers’ choices between farming systems as well as in helping policy makers to develop more sharply targeted policies

Nitrogen management for enhanced protein content in wheat in the Black Soil Zone

Non-Peer Reviewe

The Frequency Dependence of Critical-velocity Behavior in Oscillatory Flow of Superfluid Helium-4 Through a 2-micrometer by 2-micrometer Aperture in a Thin Foil

The critical-velocity behavior of oscillatory superfluid Helium-4 flow through a 2-micrometer by 2-micrometer aperture in a 0.1-micrometer-thick foil has been studied from 0.36 K to 2.10 K at frequencies from less than 50 Hz up to above 1880 Hz. The pressure remained less than 0.5 bar. In early runs during which the frequency remained below 400 Hz, the critical velocity was a nearly-linearly decreasing function of increasing temperature throughout the region of temperature studied. In runs at the lowest frequencies, isolated 2 Pi phase slips could be observed at the onset of dissipation. In runs with frequencies higher than 400 Hz, downward curvature was observed in the decrease of critical velocity with increasing temperature. In addition, above 500 Hz an alteration in supercritical behavior was seen at the lower temperatures, involving the appearance of large energy-loss events. These irregular events typically lasted a few tens of half-cycles of oscillation and could involve hundreds of times more energy loss than would have occurred in a single complete 2 Pi phase slip at maximum flow. The temperatures at which this altered behavior was observed rose with frequency, from ~ 0.6 K and below, at 500 Hz, to ~ 1.0 K and below, at 1880 Hz.Comment: 35 pages, 13 figures, prequel to cond-mat/050203

Degree of Phosphorus Saturation as a Predictor of Redox-Induced Phosphorus Release from Flooded Soils to Floodwater

Phosphorus (P) loss from soils is often enhanced under flooded, anaerobic conditions, increasing the risk of freshwater eutrophication. We aimed to develop a predictive tool to identify soils with greater P release potential under summer‐flooded conditions, which would help in developing strategies to mitigate P losses. One in situ mesocosm study was conducted in field plots with three treatments: cattle manure amended, monoammonium phosphate amended, and unamended. Two ex situ field mesocosm studies were conducted, each having 12 surface soils from agricultural fields. Prior to flooding, soils were analyzed for various soil test P (STP, intensity) and P sorption measures (capacity), and degree of P saturation (DPS) indices were calculated using different intensity and capacity combinations. Mesocosms were flooded and redox potential, pore water, and floodwater dissolved reactive P (DRP) concentrations were determined periodically up to 42 (in situ) and 56 d (ex situ) after the onset of flooding. Floodwater DRP increased significantly in most soils with flooding time, and the maximum DRP (DRPmax) was considered as the flooding‐induced P release risk. Relationships between floodwater DRPmax and STP or DPS indices were established separately for low‐P (Olsen P ≤ 30 mg kg−1) and high‐P (>30 mg kg−1) soils. Several STP indices effectively predicted the P release risk from high‐P soils, but not from low‐P soils. However, DPS calculated using Olsen P (intensity) and P sorption capacity or P saturation index (capacity) performed better in predicting summer flooding‐induced P release across all soil categories, with a higher predictive power."This work was supported by the Manitoba Conservation and Water Stewardship Fund, Environment Canada through the Lake Winnipeg Basin Stewardship Fund (EC no. 1300328), and a University of Winnipeg major grant. We also acknowledge the Manitoba Graduate Scholarship program and the University of Winnipeg Graduate Assistantship Program."https://acsess.onlinelibrary.wiley.com/doi/10.2134/jeq2019.04.015

Effect of Intraduodenal Bile and Na-Taurodeoxycholate on Exocrine Pancreatic Secretion and on Plasma Levels of Secretin, Pancreatic Polypeptide, and Gastrin in Man

The effect of intraduodenally administered cattle bile (CB) and Na-taurodeoxycholate (TDC) on basal pancreatic secretion and plasma levels of secretin, pancreatic polypeptide (PP), and gastrin were investigated on two separate days in 10 fasting volunteers. Doses of 2-6 g CB and 20&600 mg TDC were given intraduodenally at 65-min intervals. Volume, bicarbonate, lipase, trypsin, amylase, and bilirubin were measured in 10-min fractions of duodenal juice, and GI peptides determined by radioimmunoassay. CB and TDC enhanced significantly and dose-dependently volume, bicarbonate and enzyme secretion, and plasma secretin and PP levels. In contrast, plasma gastrin showed only a marginal increase. We conclude that the hydrokinetic effect of intraduodenal CB and TDC is at least partially mediated by secretin. Gastrin could be ruled out as a mediator of the ecbolic effect, whereas other GI peptides, primarily CCK, and/or neural mechanisms must be considered possible mediators. Both pathways may also play a role in the PP release

Eclipse-Ballooning 2017: The U of MN – Twin Cities Experience

The stratospheric ballooning team at the U of MN – Twin Cities started working on eclipse-ballooning in the fall of 2013, even before the Montana Space Grant announced their plan to organize a national Eclipse Ballooning Project. Our team promptly signed up to assist their effort, and have been heavily involved ever since. This presentation will discuss our eclipse-ballooning efforts and progress over the past 4 years. Our experiences include experimenting with a GoPro-based video-telemetry system (which ultimately was not as successful as Montana’s Raspberry-Pi-based system), adopting (then helping test, modify, and teach other teams to learn to use) the Montana telemetry system, practicing with up-range and down-range ground station placement, developing and testing passive anti-rotation devices and active camera-pointing devices to improve video quality, landing two eclipse-telemetry systems in Minnesota lakes one week before the eclipse (ouch!), flying five balloon stacks during the eclipse from near Grand Island, NE, and organizing/hosting AHAC 2017. We will also discuss ways in which we have already begun to use the telemetry equipment for non-eclipse balloon missions. The eclipse project has greatly expanded our HAB network and ballooning capabilities in multiple different directions, and will continue to strongly influence our stratospheric ballooning program for years to come

Light emission from a scanning tunneling microscope: Fully retarded calculation

The light emission rate from a scanning tunneling microscope (STM) scanning a noble metal surface is calculated taking retardation effects into account. As in our previous, non-retarded theory [Johansson, Monreal, and Apell, Phys. Rev. B 42, 9210 (1990)], the STM tip is modeled by a sphere, and the dielectric properties of tip and sample are described by experimentally measured dielectric functions. The calculations are based on exact diffraction theory through the vector equivalent of the Kirchoff integral. The present results are qualitatively similar to those of the non-retarded calculations. The light emission spectra have pronounced resonance peaks due to the formation of a tip-induced plasmon mode localized to the cavity between the tip and the sample. At a quantitative level, the effects of retardation are rather small as long as the sample material is Au or Cu, and the tip consists of W or Ir. However, for Ag samples, in which the resistive losses are smaller, the inclusion of retardation effects in the calculation leads to larger changes: the resonance energy decreases by 0.2-0.3 eV, and the resonance broadens. These changes improve the agreement with experiment. For a Ag sample and an Ir tip, the quantum efficiency is $\approx$ 10$^{-4}$ emitted photons in the visible frequency range per tunneling electron. A study of the energy dissipation into the tip and sample shows that in total about 1 % of the electrons undergo inelastic processes while tunneling.Comment: 16 pages, 10 figures (1 ps, 9 tex, automatically included); To appear in Phys. Rev. B (15 October 1998