1,244 research outputs found
Community Management of Natural Resources in Africa: Impacts, Experiences and Future Directions
More than twenty years have passed since community-based natural resource management (CBNRM) rose to prominence in different parts of Africa as a strategy for rural development, local empowerment, and conservation. Led by new ideas about the merits of decentralized, collective resource governance regimes, and creative field experiments such as Zimbabwe's CAMPFIRE, these community-based approaches evolved in a wide range of ecological, political, and social contexts across Africa. This review provides an unprecedented pan-African synthesis of CBNRM, drawing on multiple authors and a wide range of documented experiences from Southern, Eastern, Western and Central Africa. The review discusses the degree to which CBNRM has met poverty alleviation, economic development and nature conservation objectives. In its concluding chapter, the report suggests a way forward for strengthening CBNRM and addressing key challenges in the years ahead
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Comparative sterility effects of gamma radiation and a chemosterilant on Drosophila melanogaster Meigen.
Autonomous rendezvous and capture development infrastructure
In the development of the technology for autonomous rendezvous and docking, key infrastructure capabilities must be used for effective and economical development. This involves facility capabilities, both equipment and personnel, to devise, develop, qualify, and integrate ARD elements and subsystems into flight programs. One effective way of reducing technical risks in developing ARD technology is the use of the ultimate test facility, using a Shuttle-based reusable free-flying testbed to perform a Technology Demonstration Test Flight which can be structured to include a variety of additional sensors, control schemes, and operational approaches. This conceptual testbed and flight demonstration will be used to illustrate how technologies and facilities at MSFC can be used to develop and prove an ARD system
Can You Imagine
https://digitalcommons.library.umaine.edu/mmb-vp/4953/thumbnail.jp
Taro Leaf Blight in Hawaii
This publication discusses the causal pathogen, symptoms of the diseae, and management options for taro leaf blight in Hawai‘i
Fractional Generalizations of Zakai Equation and Some Solution Methods
The paper discusses fractional generalizations of Zakai equations arising in filtering problems. The derivation of the fractional Zakai equation, existence and uniqueness of its solution, as well as some methods of solution to the fractional filtering problem, including fractional version of the particle flow method, are presented
Fractional Generalizations of Filtering Problems and Their Associated Fractional Zakai Equation
In this paper we discuss fractional generalizations of the filtering problem. The ”fractional” nature comes from time-changed state or observation processes, basic ingredients of the filtering problem. The mathematical feature of the fractional filtering problem emerges as the Riemann-Liouville or Caputo-Djrbashian fractional derivative in the associated Zakai equation. We discuss fractional generalizations of the nonlinear filtering problem whose state and observation processes are driven by time-changed Brownian motion or/and Lévy process
Optimized Compilation of Aggregated Instructions for Realistic Quantum Computers
Recent developments in engineering and algorithms have made real-world
applications in quantum computing possible in the near future. Existing quantum
programming languages and compilers use a quantum assembly language composed of
1- and 2-qubit (quantum bit) gates. Quantum compiler frameworks translate this
quantum assembly to electric signals (called control pulses) that implement the
specified computation on specific physical devices. However, there is a
mismatch between the operations defined by the 1- and 2-qubit logical ISA and
their underlying physical implementation, so the current practice of directly
translating logical instructions into control pulses results in inefficient,
high-latency programs. To address this inefficiency, we propose a universal
quantum compilation methodology that aggregates multiple logical operations
into larger units that manipulate up to 10 qubits at a time. Our methodology
then optimizes these aggregates by (1) finding commutative intermediate
operations that result in more efficient schedules and (2) creating custom
control pulses optimized for the aggregate (instead of individual 1- and
2-qubit operations). Compared to the standard gate-based compilation, the
proposed approach realizes a deeper vertical integration of high-level quantum
software and low-level, physical quantum hardware. We evaluate our approach on
important near-term quantum applications on simulations of superconducting
quantum architectures. Our proposed approach provides a mean speedup of
, with a maximum of . Because latency directly affects the
feasibility of quantum computation, our results not only improve performance
but also have the potential to enable quantum computation sooner than otherwise
possible.Comment: 13 pages, to apper in ASPLO
I\u27m Not Jealous : But I Just Don\u27t Like It
https://digitalcommons.library.umaine.edu/mmb-vp/4726/thumbnail.jp
Eccentricity evolution of giant planet orbits due to circumstellar disk torques
The extrasolar planets discovered to date possess unexpected orbital
elements. Most orbit their host stars with larger eccentricities and smaller
semi-major axes than similarly sized planets in our own solar system do. It is
generally agreed that the interaction between giant planets and circumstellar
disks (Type II migration) drives these planets inward to small radii, but the
effect of these same disks on orbital eccentricity, e, is controversial.
Several recent analytic calculations suggest that disk-planet interactions can
excite eccentricity, while numerical studies generally produce eccentricity
damping. This paper addresses this controversy using a quasi-analytic approach,
drawing on several preceding analytic studies. This work refines the current
treatment of eccentricity evolution by removing several approximations from the
calculation of disk torques. We encounter neither uniform damping nor uniform
excitation of orbital eccentricity, but rather a function de/dt that varies in
both sign and magnitude depending on eccentricity and other solar system
properties. Most significantly, we find that for every combination of disk and
planet properties investigated herein, corotation torques produce negative
values of de/dt for some range in e within the interval [0.1, 0.5]. If
corotation torques are saturated, this region of eccentricity damping
disappears, and excitation occurs on a short timescale of less than 0.08 Myr.
Thus, our study does not produce eccentricity excitation on a timescale of a
few Myr -- we obtain either eccentricity excitation on a short time scale, or
eccentricity damping on a longer time scale. Finally, we discuss the
implications of this result for producing the observed range in extrasolar
planet eccentricity.Comment: 24 pages including 13 figures; accepted to ICARU
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