Fallow replacement using indianhead lentils: water use, yield and oil nitrogen

Because of increased costs of fertilizer and evidence of declining soil quality there has been renewed interest in crop rotations using legumes in the traditional spring wheat-fallow rotation areas of the semiarid northern Great Plains. Objectives were to test a "green fallow" method of farming as a system to build soil nitrogen and efficiently use water. We compared mechanical fallow using sweeps (N1F) and chemical fallow (CF) to green fallow. Fallow treatments MF and CF received 30 lb-N/acre. as N1-14NO3 broadcast prior to seeding wheat (Triticum aestivum L.). Lentils (Lens culinaris Medikus, cv. `Indianhead') were grown as a green manure crop in a green fallow-spring wheat rotation. The experiment was started in 1991 as a randomized complete block with four replications and MF as control. Soil was a Williams loam ( fine-loamy, mixed Typic Argiboroll) 7 miles north of Culbertson Montana. At full bloom, lentils were either killed by disking (GMMF) or chemical burn-down (GMCF). Average dry-weight of Indianhead lentils for 1991, 1992, and 1993 was 1500 lb/acre compared to an average of 4700 lb/acre for 1994 and 1995. Average water use by lentils in 1991, 1992, and 1993 was 10.6 inches. In contrast, MF and CF lost 9.9 inches. Average water use by lentils in 1994 and 1995 was 12.9 inches which was significantly more than the loss of 10.7 inches on MF and CF. At spring planting, there were no differences in soil water content among treatments. Wheat yield was 25% less on green fallow compared to MF and CF. Soil NO3 -N levels were 35 % lower on green fallow rotations than MF and CF rotations. There were no differences among treatments in nitrogen mineralization rates in 1993 following two cycles of green manure. Lack of available nitrogen, rather than lack of soil water, appears to have restricted wheat production on green fallow treatments

Water use and biomass production of oat-pea hay and lentil in a semiarid climate

Suitability of alternative crops in the northern Great Plains remains a question because of water limitations. Objectives were to compare water use of an oat (Avena sativa L.)—pea (Pisum sativum L.) mix grown for hay (OPH) to that of black lentil (Lens culinaris Medikus cv. Indianhead) grown as green manure (BL). Water use and plant biomass for OPH and BL were measured near Culbertson, MT (Site 1), during 4 yr. Soil water was measured by neutron attenuation. Precision-weighing lysimeters were used at Site 2, located 65 km southeast of Site 1, to measure water use. Soil was a Williams loam (fine-loamy, mixed, superactive, frigid Typic Argiustolls). Biomass of crops was measured biweekly. Relative feed value (RFV) based on measured neutral detergent fiber and acid detergent fiber was calculated. Biomass under OPH was 34 and 46% greater than with BL at Sites 1 and 2, respectively. At Site 1, biomass accumulated at a rate of 14 kg ha-1 mm-1 water used under BL and 23 kg ha -1 mm- 1 under OPH. Biomass accumulated at a rate of 21 kg ha- 1 mm-1 under BL and 29 kg ha -1 mm -1 under OPH at Site 2. Hay RFV, at full bloom in pea, averaged 116 (Number 2 hay), and this did not change appreciably as the crop matured to soft dough stage in oat. Oat—pea hay fits the growing conditions in the northern Great Plains and meets the needs of producers for high quality hay

An unusual occurrence of Nautilus macromphalus in a cenote in the Loyalty Islands (New Caledonia)

Exploration of a landlocked cenote on Lifou (Loyalty Islands) revealed 37 shells of the cephalopod Nautilus macromphalus Sowerby, 1849, in saltwater on the cenote floor, approximately 40 m below the water surface. The occurrence of these shells is unusual because N. macromphalus is restricted to the open marine waters surrounding the island. All of the shells are mature, and nearly all of them are unbroken, with faded red-brown color stripes. We analyzed seven shells to determine their age. Radiocarbon dating yielded ages of 6380¡30 to 7095¡30 y BP. The 238U-series radionuclides 210Pb (half-life 522.3 y) and 226Ra (half-life 51600 y) also were measured. Two of the samples showed radioactive equilibrium between the nuclides, consistent with the old radiocarbon dates, but the other five samples showed excess 210Pb. When corrected for radioactive decay, the 226Ra activities were much greater than those found in living Nautilus. We conclude that exposure to high activities of 222Rn and 226Ra in the salty groundwater of the cenote altered the activities originally incorporated into the shells. Human placement of the shells in the cavity is rejected based on their radiocarbon age and the geometry of the cenote. The most probable explanation is that the animals entered the flooded karstic system through a connection on the seaward side at approximately 7,000 y BP, during an interval of slowly rising sea level. Unable to find an exit and/or due to anoxic bottom waters, the animals were trapped and died inside. The open connection with the sea persisted for ,700 y, but after ,6400 y BP, the connection was lost, probably due to a roof collapse. This is a rare example of Nautilus in a karstic coastal basin and provides a minimum age for the appearance of N. macromphalus in the Loyalty Islands

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02

Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio

Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS

The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4 fb^-1, these states are reconstructed through their radiative decays to Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table, corrected author list, matches final version in Physical Review Letter

Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS

We present the results of a search for new, heavy particles that decay at a significant distance from their production point into a final state containing charged hadrons in association with a high-momentum muon. The search is conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV and an integrated luminosity of 33 pb^-1 collected in 2010 by the ATLAS detector operating at the Large Hadron Collider. Production of such particles is expected in various scenarios of physics beyond the standard model. We observe no signal and place limits on the production cross-section of supersymmetric particles in an R-parity-violating scenario as a function of the neutralino lifetime. Limits are presented for different squark and neutralino masses, enabling extension of the limits to a variety of other models.Comment: 8 pages plus author list (20 pages total), 8 figures, 1 table, final version to appear in Physics Letters