Alfalfa Leafcutting Bee: Management for Alfalfa Pollination in South Dakota

The alfalfa leaf-cutter bee, Megachile rotundata (Fabricius), was introduced into South D a k o t a from Utah in 1962 for alfalfa pollination testing. This leaf-cutting bee, because of its pollen collecting activmes, has shown considerable promise as a means of increasing yields of alfalfa seed. A native of Eurasia, it was introduced into eastern United States in the mid-thirties and by 1958 had moved across the country into Oregon. There is some indication that the alfalfa leaf-cutter bee may have become established in isolated locations in South Dakota during this initial cross-country movement

Case of the Disappearing Sweetclover

If you\u27ve had trouble getting a stand of sweetclover established on your farm, you\u27re not alone with your problem. The culprit is the tiny sweetclover weevil. It can be controlled by late seeding and by using DDT

Protect Forage Crops From Insects

There are nearly always insects in our forage crops; sometimes they\u27re serious, other times not. With the newer insecticides, however, we need not stand by and watch then take over when they do become serious

Alfalfa Leaf-Cutter Bee: Management for Alfalfa Pollination in South Dakota

The alfalfa leaf-cutter bee, Megachile rotundata (Fabricius), was introduced into South D a k o t a from Utah in 1962 for alfalfa pollination testing. This leaf-cutting bee, because of its pollen collecting activmes, has shown considerable promise as a means of increasing yields of alfalfa seed. A native of Eurasia, it was introduced into eastern United States in the mid-thirties and by 1958 had moved across the country into Oregon. There is some indication that the alfalfa leaf-cutter bee may have become established in isolated locations in South Dakota during this initial cross-country movement

Insecticides Increase Alfalfa Seed Production in South Dakota

Insecticide treatments increase alfalfa seed production. Since South Dakota ranks among the top states in acres of alfalfa harvested for seed, proper selection and application of insecticides is of considerable economic importance. This publication reports results of tests conducted in the state during a 5-year period to determine the most economical and effective ways to control insects that reduce alfalfa seed yields

Polarization of superfluid turbulence

We show that normal fluid eddies in turbulent helium II polarize the tangle of quantized vortex lines present in the flow, thus inducing superfluid vorticity patterns similar to the driving normal fluid eddies. We also show that the polarization is effective over the entire inertial range. The results help explain the surprising analogies between classical and superfluid turbulence which have been observed recently.Comment: 3 figure

A proposed measurement of the ß asymmetry in neutron decay with the Los Alamos Ultra-Cold Neutron Source

This article reviews the status of an experiment to study the neutron spin-electron angular correlation with the Los Alamos Ultra-Cold Neutron (UCN) source. The experiment will generate UCNs from a novel solid deuterium, spallation source, and polarize them in a solenoid magnetic field. The experiment spectrometer will consist of a neutron decay region in a solenoid magnetic field combined with several different detector possibilities. An electron beam and a magnetic spectrometer will provide a precise, absolute calibration for these detectors. An A-correlation measurement with a relative precision of 0.2% is expected by the end of 2002

Measurement of the neutron lifetime using an asymmetric magneto- gravitational trap and in situ detection

The precise value of the mean neutron lifetime, $\tau_n$, plays an important role in nuclear and particle physics and cosmology. It is a key input for predicting the ratio of protons to helium atoms in the primordial universe and is used to search for new physics beyond the Standard Model of particle physics. There is a 3.9 standard deviation discrepancy between $\tau_n$ measured by counting the decay rate of free neutrons in a beam (887.7 $\pm$ 2.2 s) and by counting surviving ultracold neutrons stored for different storage times in a material trap (878.5$\pm$0.8 s). The experiment described here eliminates loss mechanisms present in previous trap experiments by levitating polarized ultracold neutrons above the surface of an asymmetric storage trap using a repulsive magnetic field gradient so that the stored neutrons do not interact with material trap walls and neutrons in quasi-stable orbits rapidly exit the trap. As a result of this approach and the use of a new in situ neutron detector, the lifetime reported here (877.7 $\pm$ 0.7 (stat) +0.4/-0.2 (sys) s) is the first modern measurement of $\tau_n$ that does not require corrections larger than the quoted uncertainties.Comment: 9 pages, 3 figures, 2 table

Status of the UCNτ experiment

The neutron is the simplest nuclear system that can be used to probe the structure of the weak interaction and search for physics beyond the standard model. Measurements of neutron lifetime and β-decay correlation coefficients with precisions of 0.02% and 0.1%, respectively, would allow for stringent constraints on new physics. The UCNτ experiment uses an asymmetric magneto-gravitational UCN trap with in situ counting of surviving neutrons to measure the neutron lifetime, τ_n = 877.7s (0.7s)_(stat) (+0.4/−0.2s)_(sys). We discuss the recent result from UCNτ, the status of ongoing data collection and analysis, and the path toward a 0.25 s measurement of the neutron lifetime with UCNτ