71,382 research outputs found
A Review of the South Pacific Tuna Baitfisheries: Small Pelagic Fisheries Associated with Coral-Reefs
A review is given of current information concerning small pelagic fishes exploited for tuna bait in the South Pacific. These fishes are usually caught over or near coral reefs using light attraction and lift nets. The most common and widespread species are anchovies (Engraulidae), sprats (Clupeidae), silversides (Atherinidae), and herrings (Clupeidae). Recorded yields ranged from 0.5 to 2.6t/km2, and methods are described to estimate potential yields empirically in the absence of catch data. Environmental effects on small pelagic fish production are discussed, and evidence is presented to suggest that rainfall markedly affects stolephorid anchovy production. Some species of small pelagic fish, such as Selar spp., Decapterus spp., and Herklotsichthys sp., have been fished traditionally by artisanal fishermen, but anchovy and sprat stocks were probably unexploited prior to pole-and-line tuna fishing in the South Pacific
Channel and active component abstractions for WSN programming - a language model with operating system support
To support the programming of Wireless Sensor Networks, a number of unconventional programming models have evolved, in particular the event-based model. These models are non-intuitive to programmers due to the introduction of unnecessary, non-intrinsic complexity. Component-based languages like Insense can eliminate much of this unnecessary complexity via the use of active components and synchronous channels. However, simply layering an Insense implementation over an existing event-based system, like TinyOS, while proving efficacy, is insufficiently space and time efficient for production use. The design and implementation of a new language-specific OS, InceOS, enables both space and time efficient programming of sensor networks using component-based languages like Insense
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The depth of the convective boundary layer and implications for a Walker-like circulation on Mars
Radio science observations indicate that the depth of the martian convective boundary layer varies strongly with surface height, although the surface temperature does not. We show that this effect is reproduced in martian limited area models and in global climate models. The implications for the global circulation when convective boundary layer depth varies with location are considered
CMB lensing and primordial squeezed non-Gaussianity
Squeezed primordial non-Gaussianity can strongly constrain early-universe
physics, but it can only be observed on the CMB after it has been
gravitationally lensed. We give a new simple non-perturbative prescription for
accurately calculating the effect of lensing on any squeezed primordial
bispectrum shape, and test it with simulations. We give the generalization to
polarization bispectra, and discuss the effect of lensing on the trispectrum.
We explain why neglecting the lensing smoothing effect does not significantly
bias estimators of local primordial non-Gaussianity, even though the change in
shape can be >~10%. We also show how tau_NL trispectrum estimators can be well
approximated by much simpler CMB temperature modulation estimators, and hence
that there is potentially a ~10-30% bias due to very large-scale lensing modes,
depending on the range of modulation scales included. Including dipole sky
modulations can halve the tau_NL error bar if kinematic effects can be
subtracted using known properties of the CMB temperature dipole. Lensing
effects on the g_NL trispectrum are small compared to the error bar. In
appendices we give the general result for lensing of any primordial bispectrum,
and show how any full-sky squeezed bispectrum can be decomposed into orthogonal
modes of distinct angular dependence.Comment: 22 pages, 6 figures; minor edits to match published versio
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