1,669 research outputs found

    Selling Solar: Financing Household Solar Energy in the Developing World

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    Based on value chain analyses of case studies, outlines the issues and challenges for developing a solar energy industry, with a focus on the need for a financing infrastructure that serves purchasers, manufacturers, distributors, and investors

    Nonzero electron temperature effects in nonlinear mirror modes

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    The nonlinear theory of the magnetic mirror instability (MI) accounting for nonzero electron temperature effects is developed. Based on our previous low-frequency approach to the analysis of this instability and including nonzero electron temperature effects a set of equations describing nonlinear dynamics of mirror modes is derived. In the linear limit a Fourier transform of these equations recovers the linear MI growth rate in which the finite ion Larmor radius and nonzero electron temperature effects are taken into account. When the electron temperature T-e becomes of the same order as the parallel ion temperature T the growth rate of the MI is reduced by the presence of a parallel electric field. The latter arises because the electrons are dragged by nonresonant ions which are mirror accelerated from regions of high to low parallel magnetic flux. The nonzero electron temperature effect also substantially modifies the mirror mode nonlinear dynamics. When T-e similar or equal to T the transition from the linear to nonlinear regime occurred for wave amplitudes that are only half that which was inherent to the cold electron temperature limit. Further nonlinear dynamics developed with the explosive formation of magnetic holes, ending with a saturated state in the form of solitary structures or cnoidal waves. This shows that the incorporation of nonzero temperature results in a weak decrease in their spatial dimensions of the holes and increase in their depth

    Homer A. Northrop Family Papers, 1862-1967

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    Civil War correspondence to Northrop's family (1864-1865); diary (1864) relating to his service with 149th New York Volunteer Infantry Regiment near Atlanta, Ga.; land patents; history of Baldwin Township, Barnes County, N.D.; newspaper clippings; and miscellany. No papers dated 1866-1889 and 1903-1959

    Hamiltonian Theory of Adiabatic Motion of Relativistic Charged Particles

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    A general Hamiltonian theory for the adiabatic motion of relativistic charged particles confined by slowly-varying background electromagnetic fields is presented based on a unified Lie-transform perturbation analysis in extended phase space (which includes energy and time as independent coordinates) for all three adiabatic invariants. First, the guiding-center equations of motion for a relativistic particle are derived from the particle Lagrangian. Covariant aspects of the resulting relativistic guiding-center equations of motion are discussed and contrasted with previous works. Next, the second and third invariants for the bounce motion and drift motion, respectively, are obtained by successively removing the bounce phase and the drift phase from the guiding-center Lagrangian. First-order corrections to the second and third adiabatic invariants for a relativistic particle are derived. These results simplify and generalize previous works to all three adiabatic motions of relativistic magnetically-trapped particles.Comment: 20 pages, LaTeX, to appear in Physics of Plasmas (Aug, 2007

    Perturbation analysis of trapped-particle dynamics in axisymmetric dipole geometry

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    The perturbation analysis of the bounce action-angle coordinates (J,ζ)(J,\zeta) for charged particles trapped in an axisymmetric dipole magnetic field is presented. First, the lowest-order bounce action-angle coordinates are derived for deeply-trapped particles in the harmonic-oscillator approximation. Next, the Lie-transform perturbation method is used to derive higher-order anharmonic action-angle corrections. Explicit expressions (with anharmonic corrections) for the canonical parallel coordinates s(J,ζ)s(J,\zeta) and p∥(J,ζ)p_{\|}(J,\zeta) are presented, which satisfy the canonical identity {s,  p∥}(J,ζ)≡1\{s,\; p_{\|}\}(J,\zeta) \equiv 1. Lastly, analytical expressions for the bounce and drift frequencies (which include anharmonic corrections) yield excellent agreement with exact numerical results.Comment: 16 pages, 3 figure

    Stock assessment of Australian pearl perch (Glaucosoma scapulare) with data to December 2019

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    Pearl perch, Glaucosoma scapulare, are endemic to sub-tropical offshore-waters along the east coast of Australia. Pearl perch form a single genetic stock in ocean waters between Rockhampton (23.20◦ S) in Queensland and Port Jackson (33.5◦ S) in New South Wales. The species live at least 25 years and have a maximum observed size of 75 cm total length. Sexual maturity is reached at 2–4 years of age (between 25 and 45 cm total length). This assessment builds on a previous assessment that estimated the stock was at 10–40% of unfished levels in 2014. This stock assessment includes updates to input data and methodology. This assessment used a single-sex, age-structured population model, fit to age and length data, constructed within the Stock Synthesis modelling framework. The assessment modelled the dynamics of the fishery across seven fishing sectors: 1) Queensland (Qld) charter line, 2) Qld commercial line, 3) Qld recreational, 4) New South Wales (NSW) charter line, 5) NSW commercial trap fishing, 6) NSW commercial line, and 7) NSW recreational. Sixteen scenarios were run, covering a range of modelling assumptions. Base case (Project Team recommended) results estimated spawning biomass to be 22% (14–46% range across scenarios) of unfished spawning biomass at the beginning of 2020

    Protracted effects of chronic stress on serotonin-dependent thermoregulation

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    Chronic stress is known to affect serotonin (5HT) neurotransmission in the brain and to alter body temperature. The body temperature is controlled in part, by the medial preoptic area (mPOA) of the hypothalamus. To investigate the effect of chronic stress on 5HT and how it affects body temperature regulation, we examined whether exposure to a chronic unpredictable stress (CUS) paradigm produces long-term alterations in thermoregulatory function of the mPOA through decreased 5HT neurotransmission. Adult male Sprague-Dawley rats underwent 21 d of CUS. Four days after the last stress exposure, basal body temperature in the home cage and body temperature in a cold room maintained at 10 °C were recorded. The CUS rats had significantly higher subcutaneous basal body temperature at 13:00 h compared to unstressed (NoStress) rats. Whereas the NoStress rats were able to significantly elevate body temperature from basal levels at 30 and 60 min of exposure to the cold room, the CUS rats showed a hypothermic response to the cold. Treatment during CUS with metyrapone, a corticosterone synthesis inhibitor, blocked stress-induced decrease in body temperature in response to the cold challenge. CUS also decreased 5HT transporter protein immunoreactivity in the mPOA and 5HT2A/C agonist injection into the mPOA after CUS exposure caused stressed rats to exhibit a sensitized hyperthermic response to cold. These results indicate that the CUS induced changes to the 5HTergic system alter mPOA function in thermoregulation. These findings help us to explain the mechanisms underlying chronic stress-induced disorders such as chronic fatigue syndrome wherein long lasting thermoregulatory deficits are observed
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