5,352 research outputs found

    First Report of the Alfalfa Blotch Leafminer (Diptera: Agromyzidae), and Selected Parasites (Hymenoptera: Eulophidae) in Minnesota and Wisconsin, USA

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    Alfalfa blotch leafminer, Agromyza frontella, has been a serious pest of alfalfa, Medicago sativa, in the northeastern U.S. and in eastern Ontario, Canada. Until recently, the western edge of the A. frontella distribution in the U.S. was limited to eastern Ohio. We document for the first time, the occurrence of A. frontella in Minnesota and Wisconsin. Alfalfa stems damaged by A. frontella, based on adult feeding punctures, obvious blotched leafmining or the presence of larvae, were first found in 3 northern Minnesota coun­ties during October, 1994. Infested counties included Lake of the Woods, Cook and Lake, all bordering western Ontario, Canada. In 1995, A. frontella was again found in Cook and Lake counties, where 99-100% of the stems, and 18-35% of the trifoliates/stem, contained larvae or exhibited obvious feeding damage. In 1996, following a more expanded survey, a total of 11 and 5 counties, in Minnesota and Wisconsin, respectively, showed some level of A. frontella feeding damage (stem samples ranged from \u3c5 to 100% infested). Based on additional counties surveyed 11 October, 1996, where A. frontella was not found, we now have a reasonable estimate of the southern edge of the distribution in Minnesota and Wisconsin. A total of 2 and 6 A. frontella adults were identified from sweep-net samples taken from fields with obvious feeding damage during 1995 (Lake Co.) and 1996 (Cook Co,), respectively. Three eulophid (Hymenoptera) parasites were reared from A. frontella-infested alfalfa stems collected during October, 1994 in Cook Co., Minn., including: Diglyphus begini, D. pulchripes, and Diglyphus sp., prob. isaea, all of which are new records. Our hypothesis is that A. frontella moved into Minnesota from Ontario Canada, via alfalfa hay purchased by northern Minnesota growers

    Dynamical steering in an electron transfer surface reaction: Oriented NO(v = 3, 0.08 < E i < 0.89 eV) relaxation in collisions with a Au(111) surface.

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    We report measurements of the incidence translational energy dependence of steric effects in collisions of NO(v = 3) molecules with a Au(111) surface using a recently developed technique to orient beams of vibrationally excited NO molecules at incidence energies of translation between 0.08 and 0.89 eV. Incidence orientation dependent vibrational state distributions of scattered molecules are detected by means of resonance enhanced multiphoton ionization spectroscopy. Molecules oriented with the N-end towards the surface exhibit a higher vibrational relaxation probability than those oriented with the O-end towards the surface. This strong orientation dependence arises from the orientation dependence of the underlying electron transfer reaction responsible for the vibrational relaxation. At reduced incidence translational energy, we observe a reduced steric effect. This reflects dynamical steering and re-orientation of the NO molecule upon its approach to the surface

    Effect of growth conditions on optical properties of CdSe/ZnSe single quantum dots

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    In this work, we have investigated the optical properties of two samples of CdSe quantum dots by using submicro-photoluminescence spectroscopy. The effect of vicinal-surface GaAs substrates on their properties has been also assessed. The thinner sample, grown on a substrate with vicinal surface, includes only dots with a diameter of less than 10 nm (type A islands). Islands of an average diameter of about 16 nm (type B islands) that are related to a phase transition via a Stranski-Krastanow growth process are also distributed in the thicker sample grown on an oriented substrate. We have studied the evolution of lineshapes of PL spectra for these two samples by improving spatial resolution that was achieved using nanoapertures or mesa structures. It was found that the use of a substrate with the vicinal surface leads to the suppression of excitonic PL emitted from a wetting layer.Comment: 2pages, 2 figures, Proceedings of International Conference On Superlattices Nano-Structures And Nano-Devices, July, Toulouse, France, to appear in the special issue of Physica

    Genetic contributions to the association between height and intelligence: Evidence from Dutch twin data from childhood to middle age.

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    A positive association between intelligence (IQ) and height has been reported previously. It is generally assumed that this association reflects the effect of childhood environment on IQ, but there is still little research supporting directly this hypothesis. We studied the association between height and IQ in 209 Dutch twin pairs at the ages of 5, 7, 10 and 12 years, 208 twin pairs at 16 and 18 years of age and 567 twin pairs and their siblings in adulthood. The heritability of height was high in all cohorts and across all ages (

    Limits on axion and light Higgs boson production in Y(1S) decays

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    We have searched for axion and light Higgs boson production in the channel Y(1S) → (a0 or h0)+gamma, where the non-interacting axion a0 and the Higgs boson h0 do not decay in the detector. We find no evidence for an axion and give an upper limit, Br(Y(1S) -&gt; a0 gamma) &lt;4.0x10(-5) (90% CL), for long-lived axions. Combining our limit with the previous search in J/Psi decays, we are able to rule out the axion in the standard model with first order QCD corrections. Our Y(1S) data also rule out a Higgs boson with mass m&lt;86 MeV

    Deep inelastic events containing a forward photon as a probe of small xx dynamics

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    We calculate the rate of producing deep inelastic events containing an energetic isolated forward photon at HERA. We quantify the enhancement arising from the leading log1/x\log 1/x gluon emissions with a view to using such events to identify the underlying dynamics.Comment: 11 pages, Latex, 7 ps figure

    Velocity-selective direct frequency-comb spectroscopy of atomic vapors

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    We present an experimental and theoretical investigation of two-photon direct frequency-comb spectroscopy performed through velocity-selective excitation. In particular, we explore the effect of repetition rate on the 5S1/25D3/2,5/2\textrm{5S}_{1/2}\rightarrow \textrm{5D}_{3/2, 5/2} two-photon transitions excited in a rubidium atomic vapor cell. The transitions occur via step-wise excitation through the 5P1/2,3/2\textrm{5P}_{1/2, 3/2} states by use of the direct output of an optical frequency comb. Experiments were performed with two different frequency combs, one with a repetition rate of 925\approx 925 MHz and one with a repetition rate of 250\approx 250 MHz. The experimental spectra are compared to each other and to a theoretical model.Comment: 10 pages, 7 figure

    Feasibility of a Manualized Mindful Yoga Intervention for Patients With Chronic Mood Disorders

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    Chronic mood disorders pose an important mental health problem. Individuals with these disorders experience a significant impairment, often fail to seek help, and their illnesses frequently do not respond to treatment. It is therefore important to develop innovative and attractive treatments for these disorders. Mindful yoga represents a promising treatment approach. This pilot study tested the feasibility of a 9-week manualized mindful yoga intervention for patients with chronic mood disorders. Eleven patients receiving standard treatment were recruited to complete a 9-week mindful yoga intervention. Qualitative methods were used to assess patients' experiences of the intervention and quantitative methods were used to assess psychological distress and mechanisms that play a role in chronic mood disorders. Eight patients completed the intervention and rated the overall quality of the intervention with a mean score of 8.8 (range of 8 to 9, using a scale of 1 to 10). All participants reported a reduction in psychological distress and no adverse events. Among the mechanisms that play a role in chronic mood disorders, the most potentially promising effects from the intervention were found for worry, fear of depression and anxiety, rumination, and areas related to body awareness, such as trusting bodily experiences and not distracting from sensations of discomfort. A 9-week mindful yoga intervention appears to be a feasible and attractive treatment when added to treatment as usual for a group of patients with chronic mood disorders. A randomized controlled trial to study the effects of mindful yoga is recommended

    Spin dependent structure function g_1 at low x and low Q^2

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    Theoretical description of the spin dependent structure function g_1(x,Q^2) in the region of low values of x and Q^2 is presented. It contains the Vector Meson Dominance contribution and the QCD improved parton model suitably extended to the low Q^2 domain. Theoretical predictions are compared with the recent experimental data in the low x, low Q^2 region

    Multi-Regge kinematics and the moduli space of Riemann spheres with marked points

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    We show that scattering amplitudes in planar N = 4 Super Yang-Mills in multi-Regge kinematics can naturally be expressed in terms of single-valued iterated integrals on the moduli space of Riemann spheres with marked points. As a consequence, scattering amplitudes in this limit can be expressed as convolutions that can easily be computed using Stokes' theorem. We apply this framework to MHV amplitudes to leading-logarithmic accuracy (LLA), and we prove that at L loops all MHV amplitudes are determined by amplitudes with up to L + 4 external legs. We also investigate non-MHV amplitudes, and we show that they can be obtained by convoluting the MHV results with a certain helicity flip kernel. We classify all leading singularities that appear at LLA in the Regge limit for arbitrary helicity configurations and any number of external legs. Finally, we use our new framework to obtain explicit analytic results at LLA for all MHV amplitudes up to five loops and all non-MHV amplitudes with up to eight external legs and four loops.Comment: 104 pages, six awesome figures and ancillary files containing the results in Mathematica forma
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