4,962 research outputs found
Fisheries policies for a new era
This Guidance Note presents a simple approach to analyzing the governance context for development of aquatic agricultural systems; it is intended as an aid to action research, and a contribution to effective program planning and evaluation. It provides a brief introduction to the value of assessing governance collaboratively, summarizes an analytical framework, and offers practical guidance on three stages of the process: identifying obstacles and opportunities, debating strategies for influence, and planning collaborative actions
Common-pool resources, livelihoods, and resilience: Critical challenges for governance in Cambodia
Common-pool resource management is a critical element in the interlocked challenges of food security, nutrition, poverty reduction, and environmental sustainability. This paper examines strategic policy choices and governance challenges facing Cambodia's forests and fisheries, the most economically important subsectors of agriculture that rely on common-pool resources. It then outlines policy priorities for institutional development to achieve improvements in implementing these goals. The core argument is that (1) policy support for community-based management in forestry and fisheries requires explicit prioritization to protect against threats from other types of private- and public-sector investment; and (2) the success of these initiatives depends on more systemic governance reforms that address issues of stakeholder representation, mechanisms of accountability, and institutional capacity.Development policy, environmental security, Fisheries, food security, forestry, Governance, Natural resources, social-ecological resilience,
Imaging of fuel mixture fraction oscillations in a driven system using acetone PLIF
Measurements of fuel mixture fraction are made for a jet flame in an acoustic chamber. Acoustic forcing creates a
spatially-uniform, temporally-varying pressure field which results in oscillatory behavior in the flame . Forcing is at 22,27, 32, 37, and 55 Hz. To asses the oscillatory behavior, previous work included chemiluminescence, OH PUF, nitric oxide PUF imaging, and fuel mixture fraction measurements by infrared laser absorption. While these results illuminated what was happening to the flame chemistry, they did not provide a complete explanation as to why these things were happening. In this work, the fuel mixture fraction is measured through PUF of acetone, which is introduced into the fuel stream as a marker. This technique enables a high degree of spatial resolution of fuel/air mixture value. Both non-reacting and reacting cases were measured and comparisons are drawn with the results from the previous work. It is found that structure in the mixture fraction oscillations is a major contributor to the magnitude of the flame oscillations
Solomon Islands: Essential aspects of governance for Aquatic Agricultural Systems in Malaita Hub
In late 2012, a governance assessment was carried out as part of the diagnosis phase of rollout of the CGIAR Aquatic Agricultural Systems Program in Malaita Hub in Solomon Islands. The purpose of the assessment was to identify and provide a basic understanding of essential aspects of governance related to Aquatic Agricultural Systems in general, and more specifically as a case study in natural resource management. The underlying principles of the approach we have taken are drawn from an approach known as “Collaborating for Resilience” (CORE), which is based on bringing all key stakeholders into a process to ensure that multiple perspectives are represented (a listening phase), that local actors have opportunities to influence each other’s understanding (a dialogue phase), and that ultimately commitments to action are built (a choice phase) that would not be possible through an outsider’s analysis alone. This report begins to address governance from an AAS perspective, using input from AAS households and other networked stakeholders. We attempt to summarize governance issues that are found not only within the community but also, and especially, those that are beyond the local level, both of which may need to be addressed by the AAS program
Inelastic effects in molecular junctions in the Coulomb and Kondo regimes: Nonequilibrium equation-of-motion approach
Inelastic effects in the Coulomb blockade and Kondo regimes of electron
transport through molecular junctions are considered within a simple
nonequilibrium equation-of-motion (EOM) approach. The scheme is
self-consistent, and can qualitatively reproduce the main experimental
observations of vibrational features in Coulomb blockade [H.Park et al., Nature
407, 57 (2000)] and Kondo [L.H.Yu et al., Phys. Rev. Lett. 93, 266802 (2004)]
regimes. Considerations similar to the equilibrium EOM approach by Meir et al.
[Phys. Rev. Lett. 66, 3048 (1991); ibid. 70, 2601 (1993)] are used on the
Keldysh contour to account for the nonequilibrium nature of the junction, and
dressing by appropriate Franck-Condon (FC) factors is used to account for
vibrational features. Results of the equilibrium EOM scheme by Meir et al. are
reproduced in the appropriate limit.Comment: 12 pages, 5 figure
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Soft X-ray seeding studies for the SLAC Linac Coherent Light Source II
We present the results from studies of soft X-ray seeding options for the LCLS-II X-ray free electron laser (FEL) at SLAC. The LCLS-II will use superconducting accelerator technology to produce X-ray pulses at up to 1 MHz repetition rate using 4 GeV electron beams. If properly seeded, these pulses will be nearly fully coherent, and highly stable in photon energy, bandwidth, and intensity, thus enabling unique experiments with intense high-resolution soft X-rays. Given the expected electron beam parameters from start to end simulations and predicted FEL performance, our studies reveal echo enabled harmonic generation (EEHG) and soft X-ray self-seeding (SXRSS) as promising and complementary seeding methods. We find that SXRSS has the advantage of simplicity and will deliver 5-35 times higher spectral brightness than EEHG in the 1-2 nm range, but lacks some of the potential for phase-stable multipulse and multicolor FEL operations enabled by external laser seeding with EEHG
Molecular transport junctions: Current from electronic excitations in the leads
Using a model comprising a 2-level bridge connecting free electron reservoirs
we show that coupling of a molecular bridge to electron-hole excitations in the
leads can markedly effect the source-drain current through a molecular
junction.In some cases, e.g. molecules that exhibit strong charge transfer
transitions, the contribution from electron-hole excitations can exceed the
Landauer elastic current and dominate the observed conduction.Comment: 4 pages, 2 figures, submitted to PR
Cooperative effects in nuclear excitation with coherent x-ray light
The interaction between super-intense coherent x-ray light and nuclei is
studied theoretically. One of the main difficulties with driving nuclear
transitions arises from the very narrow nuclear excited state widths which
limit the coupling between laser and nuclei. In the context of direct
laser-nucleus interaction, we consider the nuclear width broadening that occurs
when in solid targets, the excitation caused by a single photon is shared by a
large number of nuclei, forming a collective excited state. Our results show
that for certain isotopes, cooperative effects may lead to an enhancement of
the nuclear excited state population by almost two orders of magnitude.
Additionally, an update of previous estimates for nuclear excited state
population and signal photons taking into account the experimental advances of
the x-ray coherent light sources is given. The presented values are an
improvement by orders of magnitude and are encouraging for the future prospects
of nuclear quantum optics.Comment: 22 pages, 4 figures, 5 tables; updated to the published version, one
additional results tabl
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