In situ magnetoresistance measurements of ferromagnetic nanocontacts in the Lorentz transmission electron microscope

We report on in situ magnetoresistance measurements of a 30-nm-wide ferromagnetic nanocontact with simultaneous magnetic imaging in the Lorentz transmission electron microscope. The magnetoresistive measurements are correlated with the micromagnetic configuration of the sample. This allows us to assign characteristic features in the magnetoresistance curves to different magnetic configurations of the sample. From our experiments we can conclude that the micromagnetic configuration of the whole sample—not only the nanocontact region—has to be taken into account for the interpretation of magnetoresistive effects or hysteresis loops. Micromagnetic simulations were performed which confirm the experimental results

Interaction Between Visual and Phonotactic Orientation During Flight in \u3ci\u3eMagicicada Cassini\u3c/i\u3e (Homoptera: Cicadidae)

Visual and phonotactic orientation often occur simultaneously in diurnal cicadas. and these animals generally have their largest sensory elaboration in eyes and hearing organs. Phonotactic orientation occurs principally during flight. Males and females of Magicicada cassini commonly perform low- altitude « 5 m) and short-distance « 15 m) flights in their natural habitat at flight speeds of 3 to 6 m/s. During flight, the long body axis is tilted 10° to Q , head upward. Wing beat frequencies of tethered animals at 24° to 26°C averaged 28.8 Hz. Body temperature in the field for flying individuals aver- aged 4.6°C above ambient. Compound eyes of females possess about 7% more facets than males, and the binocular field of view for both is especially expanded dorsa-frontally, frontally, and fronto-ventrally. The role of vision for phonoresponses, and in flight and landing behavior. was studied in nature by comparing controls with cicadas with eyes partly to completely covered with aluminum paint. Cicadas with their three ocelli covered behaved like controls and exhibited low-altitude and short-distance flights with landings on neighboring shrubs, as did cicadas with only both caudal halves or both dorsal halves of the compound eyes covered. Those with both compound eyes covered completely (with or without additionally covering the three ocelli) flew to higher altitudes and for longer distances. Higher and longer flight courses were also seen in cicadas (A) with only one compound eye covered. which in addition circled during walking and flight toward the side of unrestricted vision, (B) with both frontal or both ventral halves of their compound eyes covered. and (C) with either the binocular or monocular fields of the eyes covered. Thus, the paired fronta-antero-ventral regions of the compound eyes provide visual information for habitat-dependent low-altitude flights and landings. Females with intact compound eyes and ocelli responded to playbacks of just the frequency/intensity sweep at the end of the buzz in calling songs of a male by flying within 1.2 m above the ground and landing on a nylon screen- covered small bush directly above the loudspeaker from distances of 2 to 8 m. mostly from lower vegetation. Males that were blinded, or blinded and deafened, sang less and flew less than normal males. However. they performed all of those behaviors, and all also walked and fed. Periodical cicadas (Magicicada, Tibicininae) are known for synchronized adult emergence and noisy aggregations of millions of individuals of three intermingled species in each brood population (Alexander and Moore 1962). Broods are isolated geographically and chronologically, such that in some years no periodical cicada adults emerge, and most areas of the eastern United States have only one brood population appearing as adults at intervals of either 13 or 17 years. In all Magicicada species, daily flights affect spacing and aggregation of both sexes during feeding, chorusing, mating, and ovipositing. Flights are mediated by both acoustical and visual cues. Each species in these aggregations establishes mating leks. These aggregations continue to mix, every day and unpredictably, during the emergence period. Toward the end of the reproductive season, males die sooner than females, leading to little or no chorusing, and then females disperse progressively further from the lek sites. The cohesive effect of the acoustical cues of chorusing males on these cicada populations is obvious. Both sexes of all six species of periodical cicadas live and feed on shrubs and trees of different species, sizes, and shapes, and females lay eggs in their living twigs. Their niches overlap almost completely, the three species of 13­ year or 17-year cicadas being separated principally by diurnal acoustic behavior leading to aggregation sites that change every day and are seldom exclusive to a single Magicicada species. Adults frequently change location in these complex visual environments by short-distance and low-altitude flights. which we call bush-hopping. These flights are associated with sound communication and reproductive activities and are most commonly observed during bright sunlight and at ambient temperatures above 25°C with little wind (Alexander and Moore 1958,1962; Dunning et al. 1979). Otte (1990) and Toms (1992) discuss the common correlation between hearing and flying in orthop­teroid insects, interactions basically similar to those found in cicadas. The present paper describes the interaction of vision (compound eyes and ocelli) and phonoresponses of males and females of Magicicada cassini (Fisher) in walking, but especially in flight and landing behavior, within a natural habitat

Study of beauty hadron decays into pairs of charm hadrons

First observations of the decays Λb 0 → Λc +D(s) - are reported using data corresponding to an integrated luminosity of 3fb-1 collected at 7 and 8 TeV center-of-mass energies in proton-proton collisions with the LHCb detector. In addition, the most precise measurement of the branching fraction B(Bs 0→D+Ds -) is made and a search is performed for the decays B(s) 0→Λc +Λc -. The results obtained are B(Λb 0→Λc +D-)/ B(Λb 0→Λc +D s -)=0.042±0.003(stat)±0.003(syst), [B(Λb 0→Λc +D s -)/B(B̄0→D+D s -)]/[B(Λb 0→Λ c +π-)/B(B̄0→D +π-)]=0.96±0.02(stat)±0.06(syst),B(B s 0→D+Ds -)/ B(B̄0→D+Ds -)=0. 038±0.004(stat)±0.003(syst),B(B̄0→Λ c +Λc -)/B(B̄ 0→D+Ds -)<0.0022[95%C.L.], B(Bs 0→Λc +Λ c -)/B(Bs 0→D+D s -)<0.30[95%C.L.]. Measurement of the mass of the Λb 0 baryon relative to the B̄0 meson gives M(Λb 0)-M(B̄0)=339. 72±0.24(stat)±0.18(syst)MeV/c2. This result provides the most precise measurement of the mass of the Λb 0 baryon to date

Effective lifetime measurements in the B-s(0) -> K+K-, B-0 -> K+pi(-) and B-s(0) -> pi K-+(-) decays

Measurements of the effective lifetimes in the View the MathML source, B0→K+π− and View the MathML source decays are presented using 1.0 fb−1 of pp collision data collected at a centre-of-mass energy of 7 TeV by the LHCb experiment. The analysis uses a data-driven approach to correct for the decay time acceptance. This is the most precise determination to date of the effective lifetime in the View the MathML source decay and provides constraints on contributions from physics beyond the Standard Model to the View the MathML source mixing phase and the width difference ΔΓs

Measurement of the CP-violating phase phi(s) in (B)over-bar(s)(0) -> J / psi pi(+)pi(-) decays

The mixing-induced CP -violating phase ϕs in View the MathML source and View the MathML source decays is measured using the J/ψπ+π− final state in data, taken from 3 fb−1 of integrated luminosity, collected with the LHCb detector in 7 and 8 TeV centre-of-mass pp collisions at the LHC. A time-dependent flavour-tagged amplitude analysis, allowing for direct CP violation, yields a value for the phase ϕs=70±68±8 mrad. This result is consistent with the Standard Model expectation and previous measurements

Measurement of ψ(2S) polarisation in pp collisions at √s = 7 TeV

The polarisation of prompt ψ(2S) mesons is measured by performing an angular analysis of ψ(2S) → μ+μ- decays using proton-proton collision data, corresponding to an integrated luminosity of 1.0 fb-1, collected by the LHCb detector at a centre-of-mass energy of 7 TeV. The polarisation is measured in bins of transverse momentum pT and rapidity y in the kinematic region 3.5 < pT < 15 GeV/c and 2.0 < y < 4.5, and is compared to theoretical models. No significant polarisation is observed

Measurement of the Bc +meson lifetime using Bc +→J/ψμ+νμX decays

The lifetime of the B+ c meson is measured using semileptonic decays having a J/ψ meson and a muon in the final state. The data, corresponding to an integrated luminosity of 2 fb-1, are collected by the LHCb detector in pp collisions at a centre-of-mass energy of 8 TeV. The measured lifetime is τ = 509 ± 8 ± 12 fs, where the first uncertainty is statistical and the second is systematic