632 research outputs found
Temperature and Manure Placement in a Snowpack Affect Nutrient Release from Dairy Manure During Snowmelt
Agricultural nutrient management is an issue due to N and P losses from fields and water quality degradation. Better information is needed on the risk of nutrient loss in runoff from dairy manure applied in winter. We investigated the effect of temperature on nutrient release from liquid and semisolid manure to water, and of manure quantity and placement within a snowpack on nutrient release to melting snow. Temperature did not affect manure P and NH4–N release during water extraction. Manure P release, but not NH4–N release, was significantly influenced by the water/manure solids extraction ratio. During snowmelt, manure P release was not significantly affected by manure placement in the snowpack, and the rate of P release decreased as application rate increased. Water extraction data can reliably estimate P release from manure during snowmelt; however, snowmelt water interaction with manure of greater solids content and subsequent P release appears incomplete compared with liquid manures. Manure NH4–N released during snowmelt was statistically the same regardless of application rate. For the semisolid manure, NH4–N released during snowmelt increased with the depth of snow covering it, most likely due to reduced NH3 volatilization. For the liquid manure, there was no effect of manure placement within the snowpack on NH4–N released during snowmelt. Water extraction data can also reliably estimate manure NH4–N release during snowmelt as long as NH3 volatilization is accounted for with liquid manures for all placements in a snowpack and semisolid manures applied on top of snow
Crónica de Derecho Internacional Público. Año 2006
El presente artÃculo expone los desarrollos habidos durante el año 2006 en diversos sectores e instituciones del Derecho Internacional Público: Organización de las Naciones Unidas, mantenimiento de la paz y la seguridad internacionales, Tribunales internacionales, donde se exponen los casos resueltos por la Corte Internacional de Justicia y el Consejo General de la Organización Mundial del Comercio, asà como la celebración del décimo aniversario del Tribunal Internacional para el Derecho del Mar, Derechos Humanos, donde se destaca la creación del Consejo de Derechos Humanos como órgano que sucede a la Comisión de Derechos Humanos, y Acuerdos internacionales de interés para España en 2006, concluidos, aplicados provisionalmente o entrados en vigor durante el año.This articles presents the developments occurred during 2006 in several fields and institutions of Public International Law: United Nations Organisation, the maintenance of international peace and security, international courts, where the cases ruled by the International Court of Justice and the General Council of the World Trade Organisation are presented, as well as the celebrations ot the tenth anniversary of the International Tribunal for the Law of the Sea, Human Rights, matter about which the creation of the Human Rights Council, as the body that succeeds the Human Rights Commission, is emphasized, and international agreements that have had interest for Spain in 2006, signed, provisionally enforced or come into force during that year
Quantum Monte Carlo Studies of Relativistic Effects in Light Nuclei
Relativistic Hamiltonians are defined as the sum of relativistic one-body
kinetic energy, two- and three-body potentials and their boost corrections. In
this work we use the variational Monte Carlo method to study two kinds of
relativistic effects in the binding energy of 3H and 4He. The first is due to
the nonlocalities in the relativistic kinetic energy and relativistic one-pion
exchange potential (OPEP), and the second is from boost interaction. The OPEP
contribution is reduced by about 15% by the relativistic nonlocality, which may
also have significant effects on pion exchange currents. However, almost all of
this reduction is canceled by changes in the kinetic energy and other
interaction terms, and the total effect of the nonlocalities on the binding
energy is very small. The boost interactions, on the other hand, give repulsive
contributions of 0.4 (1.9) MeV in 3H (4He) and account for 37% of the
phenomenological part of the three-nucleon interaction needed in the
nonrelativistic Hamiltonians.Comment: 33 pages, RevTeX, 11 PostScript figures, submitted to Physical Review
Solutions of the Faddeev-Yakubovsky equations for the four nucleons scattering states
The Faddeev-Yakubowsky equations in configuration space have been solved for
the four nucleon system. The results with an S-wave interaction model in the
isospin approximation are presented. They concern the bound and scattering
states below the first three-body threshold. The elastic phase-shifts for the
N+NNN reaction in different () channels are given and the corresponding
low energy expansions are discussed. Particular attention is payed to the n+t
elastic cross section. Its resonant structure is well described in terms of a
simple NN interaction. First results concerning the S-matrix for the coupled
N+NNN-NN+NN channels and the strong deuteron-deuteron scattering length are
obtained.Comment: latex.tar.gz, 36 pages, 10 figures, 11 tables. To be published in
Physical Review
Weak Transitions in A=6 and 7 Nuclei
The He beta decay and Be electron capture processes are studied using
variational Monte Carlo wave functions, derived from a realistic Hamiltonian
consisting of the Argonne two-nucleon and Urbana-IX three-nucleon
interactions. The model for the nuclear weak axial current includes one- and
two-body operators with the strength of the leading two-body term--associated
with -isobar excitation of the nucleon--adjusted to reproduce the
Gamow-Teller matrix element in tritium -decay. The measured half-life of
. He is under-predicted by theory by 8%, while that of Be for
decay into the ground and first excited states of Li is over-predicted by
9%. However, the experimentally known branching ratio for these latter
processes is in good agreement with the calculated value. Two-body axial
current contributions lead to a 1.7% (4.4%) increase in the value of
the Gamow-Teller matrix element of He (Be), obtained with one-body
currents only, and slightly worsen (appreciably improve) the agreement between
the calculated and measured half-life. Corrections due to retardation effects
associated with the finite lepton momentum transfers involved in the decays, as
well as contributions of suppressed transitions induced by the weak vector
charge and axial current operators, have also been calculated and found to be
negligible.Comment: 23 pages 8 tables. submitted to Phys. Rev.
Risk Management and Adaptation for Extremes and Abrupt Changes in Climate and Oceans: Current Knowledge Gaps
Perspectives for risk management and adaptation have received ample attention in the recent IPCC Special Report on Changes in the Oceans and Cryosphere (SROCC). However, several knowledge gaps on the impacts of abrupt changes, cascading effects and compound extreme climatic events have been identified, and need further research. We focus on specific climate change risks identified in the SROCC report, namely: changes in tropical and extratropical cyclones; marine heatwaves; extreme ENSO events; and abrupt changes in the Atlantic Meridional Overturning Circulation. Several of the socioeconomic impacts from these events are not yet well-understood, and the literature is also sparse on specific recommendations for integrated risk management and adaptation options to reduce such risks. Also, past research has mostly focussed on concepts that have seen little application to real-world cases. We discuss relevant research needs and priorities for improved social-ecological impact assessment related to these major physical changes in the climate and oceans. For example, harmonised approaches are needed to better understand impacts from compound events, and cascading impacts across systems. Such information is essential to inform options for adaptation, governance and decision-making. Finally, we highlight research needs for developing transformative adaptation options and their governance
A Simple Regulatory Incentive Mechanism Applied to Electricity Transmission Pricing and Investment
A spectroscopic reflectance-based low-cost thickness measurement system for thin films: development and testing
The requirement for alternatives in roll-to-roll (R2R) processing to expand thin film inspection in wider substrates at lower costs and reduced dimensions, and the need to enable newer control feedback options for these types of processes, represents an opportunity to explore the applicability of newer reduced-size spectrometers sensors. This paper presents the hardware and software development of a novel low-cost spectroscopic reflectance system using two state-of-the-art sensors for thin film thickness measurements. The parameters to enable the thin film measurements using the proposed system are the light intensity for two LEDs, the microprocessor integration time for both sensors and the distance from the thin film standard to the device light channel slit for reflectance calculations. The proposed system can deliver better-fit errors compared with a HAL/DEUT light source using two methods: curve fitting and interference interval. By enabling the curve fitting method, the lowest root mean squared error (RMSE) obtained for the best combination of components was 0.022 and the lowest normalised mean squared error (MSE) was 0.054. The interference interval method showed an error of 0.09 when comparing the measured with the expected modelled value. The proof of concept in this research work enables the expansion of multi-sensor arrays for thin film thickness measurements and the potential application in moving environments
Femtometer Toroidal Structures in Nuclei
The two-nucleon density distributions in states with isospin , spin
=1 and projection =0 and 1 are studied in H, He,
Li and O. The equidensity surfaces for =0 distributions are
found to be toroidal in shape, while those of =1 have dumbbell shapes
at large density. The dumbbell shapes are generated by rotating tori. The
toroidal shapes indicate that the tensor correlations have near maximal
strength at fm in all these nuclei. They provide new insights and simple
explanations of the structure and electromagnetic form factors of the deuteron,
the quasi-deuteron model, and the , and =2 (-wave)
components in He, He and Li. The toroidal distribution has a
maximum-density diameter of 1 fm and a half-maximum density thickness of
0.9 fm. Many realistic models of nuclear forces predict these values,
which are supported by the observed electromagnetic form factors of the
deuteron, and also predicted by classical Skyrme effective Lagrangians, related
to QCD in the limit of infinite colors. Due to the rather small size of this
structure, it could have a revealing relation to certain aspects of QCD.Comment: 35 pages in REVTeX, 25 PostScript figure
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