1,574 research outputs found
Evaluation of agricultural ecosystem services in fallowing land based on farmers' participation and model simulation
Fallowing with green fertilizer can benefit agricultural ecosystem services (AES). Farmers in Taiwan do not implement fallow practices and plant green fertilizer because the current subsidy level (46,000 NTperha)istoolowtomanagefallowingThispaperdefinestheobjectiveofgovernmentagriculturepolicyorthefarmer’sobjectiveasmaximizationoffarmproductivityapproximatedtothevalueofsocialwelfareandAESFarmswhichdonotfollowproperfallowingpracticesoftenhavepoorlymaintainedfallowlandorleftfarmlandabandonedThisresultsinnegativeenvironmentalconsequencessuchascutworminfestationsinabandonedlandwhichinturncanaffectcropsinadjacentfarmlandsTheobjectivesofthisstudyaretwofoldFirstitdeterminestheproperfallowingsubsidybasedontheconceptofpaymentforecosystemservicestoenticemorefarmerstoparticipateinfallowingSeconditsimulatesthebenefitofplantinggreenmanureinfallowlandtothesupplyofAESbasedontherateoffarmerswhoarewillingtoparticipateinfallowlandpracticesandessentialparametersthatcanaffectsoilfertilitychangeTheapproachinvolvesaseriesofinterviewsandadevelopedempiricalmodelThevalueofAESwhentherateoffarmerparticipationis100 ) over the value at the current participation rate of 14%. This study further concludes that the appropriate fallowing subsidy has a large positive impact on AES and social welfare (e.g., benefit from food and biofuel supplies) and is seen as a basis of ecological governance for sustainable agro-ecosystems
Photoemission and x-ray absorption spectroscopy study of electron-doped colossal magnetoresistance manganite: La0.7Ce0.3MnO3 film
The electronic structure of La0.7Ce0.3MnO3 (LCeMO) thin film has been
investigated using photoemission spectroscopy (PES) and x-ray absorption
spectroscopy (XAS). The Ce 3d core-level PES and XAS spectra of LCeMO are very
similar to those of CeO2, indicating that Ce ions are far from being trivalent.
A very weak 4f resonance is observed around the Ce 4d 4f absorption edge,
suggesting that the localized Ce 4f states are almost empty in the ground
state. The Mn 2p XAS spectrum reveals the existence of the Mn(2+) multiplet
feature, confirming the Mn(2+)-Mn(3+) mixed-valent states of Mn ions in LCeMO.
The measured Mn 3d PES/XAS spectra for LCeMO agrees reasonably well with the
calculated Mn 3d PDOS using the LSDA+U method. The LSDA+U calculation predicts
a half-metallic ground state for LCeMO.Comment: 7 pages, 7 figure
Severe disruption and disorganization of dermal collagen fibrils in early striae gravidarum
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142909/1/bjd15895.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142909/2/bjd15895_am.pd
Bulk-sensitive photoemission spectroscopy of A_2FeMoO_6 double perovskites (A=Sr, Ba)
Electronic structures of Sr_2FeMoO_6 (SFMO) and Ba_2FeMoO_6 (BFMO) double
perovskites have been investigated using the Fe 2p->3d resonant photoemission
spectroscopy (PES) and the Cooper minimum in the Mo 4d photoionization cross
section. The states close to the Fermi level are found to have strongly mixed
Mo-Fe t_{2g} character, suggesting that the Fe valence is far from pure 3+. The
Fe 2p_{3/2} XAS spectra indicate the mixed-valent Fe^{3+}-Fe^{2+}
configurations, and the larger Fe^{2+} component for BFMO than for SFMO,
suggesting a kind of double exchange interaction. The valence-band PES spectra
reveal good agreement with the LSDA+U calculation.Comment: 4 pages, 3 figure
Momentum-Resolved Tunneling into Fractional Quantum Hall Edges
Tunneling from a two-dimensional contact into quantum-Hall edges is
considered theoretically for a case where the barrier is extended, uniform, and
parallel to the edge. In contrast to previously realized tunneling geometries,
details of the microscopic edge structure are exhibited directly in the voltage
and magnetic-field dependence of the differential tunneling conductance. In
particular, it is possible to measure the dispersion of the edge-magnetoplasmon
mode, and the existence of additional, sometimes counterpropagating,
edge-excitation branches could be detected.Comment: 4 pages, 3 figures, RevTex
Melting behavior of ultrathin titanium nanowires
The thermal stability and melting behavior of ultrathin titanium nanowires
with multi-shell cylindrical structures are studied using molecular dynamic
simulation. The melting temperatures of titanium nanowires show remarkable
dependence on wire sizes and structures. For the nanowire thinner than 1.2 nm,
there is no clear characteristic of first-order phase transition during the
melting, implying a coexistence of solid and liquid phases due to finite size
effect. An interesting structural transformation from helical multi-shell
cylindrical to bulk-like rectangular is observed in the melting process of a
thicker hexagonal nanowire with 1.7 nm diameter.Comment: 4 pages, 4 figure
Muon-anti-neutrino <---> electron-anti-neutrino mixing: analysis of recent indications and implications for neutrino oscillation phenomenology
We reanalyze the recent data from the Liquid Scintillator Neutrino Detector
(LSND) experiment, that might indicate anti-nu_muanti-nu_e mixing. This
indication is not completely excluded by the negative results of established
accelerator and reactor neutrino oscillation searches. We quantify the region
of compatibility by means of a thorough statistical analysis of all the
available data, assuming both two-flavor and three-flavor neutrino
oscillations. The implications for various theoretical scenarios and for future
oscillation searches are studied. The relaxation of the LSND constraints under
different assumptions in the statistical analysis is also investigated.Comment: 17 pages (RevTeX) + 9 figures (Postscript) included with epsfig.st
Structures for Interacting Composite Fermions: Stripes, Bubbles, and Fractional Quantum Hall Effect
Much of the present day qualitative phenomenology of the fractional quantum
Hall effect can be understood by neglecting the interactions between composite
fermions altogether. For example the fractional quantum Hall effect at
corresponds to filled composite-fermion Landau levels,and
the compressible state at to the Fermi sea of composite fermions.
Away from these filling factors, the residual interactions between composite
fermions will determine the nature of the ground state. In this article, a
model is constructed for the residual interaction between composite fermions,
and various possible states are considered in a variational approach. Our study
suggests formation of composite-fermion stripes, bubble crystals, as well as
fractional quantum Hall states for appropriate situations.Comment: 16 pages, 7 figure
Simulation techniques for cosmological simulations
Modern cosmological observations allow us to study in great detail the
evolution and history of the large scale structure hierarchy. The fundamental
problem of accurate constraints on the cosmological parameters, within a given
cosmological model, requires precise modelling of the observed structure. In
this paper we briefly review the current most effective techniques of large
scale structure simulations, emphasising both their advantages and
shortcomings. Starting with basics of the direct N-body simulations appropriate
to modelling cold dark matter evolution, we then discuss the direct-sum
technique GRAPE, particle-mesh (PM) and hybrid methods, combining the PM and
the tree algorithms. Simulations of baryonic matter in the Universe often use
hydrodynamic codes based on both particle methods that discretise mass, and
grid-based methods. We briefly describe Eulerian grid methods, and also some
variants of Lagrangian smoothed particle hydrodynamics (SPH) methods.Comment: 42 pages, 16 figures, accepted for publication in Space Science
Reviews, special issue "Clusters of galaxies: beyond the thermal view",
Editor J.S. Kaastra, Chapter 12; work done by an international team at the
International Space Science Institute (ISSI), Bern, organised by J.S.
Kaastra, A.M. Bykov, S. Schindler & J.A.M. Bleeke
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