9,068 research outputs found
Food and nutrition security in Timor-Leste
This report is a literature review on Food and Nutrition Security in Timor-Leste based on data from surveys conducted by the Timor-Leste National Statistics Directorate, as well as from national and international organizations working in Timor-Leste. This review was supported by the Australian Centre for International Agricultural Research (ACIAR)-funded project “Strategy for Investment in Fisheries in East Timor”. This report describes the current food and nutrition situation in Timor-Leste for the purpose of planning and implementing interventions aimed at improving food and nutrition security, especially within aquatic agricultural systems. The potential role of aquaculture in improving food and nutrition security is considered, with reference to the recently endorsed Timor-Leste National Aquaculture Development Strategy (2012-2030) developed by the National Directorate of Fisheries and Agriculture, Ministry of Agriculture and Fisheries
Gender and aquaculture: sharing the benefits equitably
Aquaculture is the fastest growing agricultural sector in the world; it can meet both the food security and cash needs of poor households in Africa and the Asia-Pacific region. Women’s involvement in aquaculture is more significant than often assumed. In many developing countries formal statistics often overlook the nature and extent of their vital contribution. Research on gender and aquaculture at the WorldFish Center identifies five key themes for consideration. 1) Market, trade and migration 2)Capabilities and well being 3)Identities and networks 4)Governance and rights 5)Climate change, disaster and resilience.Aquaculture, Women
Acoustic confinement and Stimulated Brillouin Scattering in integrated optical waveguides
We examine the effect of acoustic mode confinement on Stimulated Brillouin
Scattering in optical waveguides that consist of a guiding core embedded in a
solid substrate. We find that SBS can arise due to coupling to acoustic modes
in three different regimes. First, the acoustic modes may be guided by total
internal reflection; in this case the SBS gain depends directly on the degree
of confinement of the acoustic mode in the core, which is in turn determined by
the acoustic V-parameter. Second, the acoustic modes may be leaky, but may
nevertheless have a sufficiently long lifetime to have a large effect on the
SBS gain; the lifetime of acoustic modes in this regime depends not only on the
contrast in acoustic properties between the core and the cladding, but is also
highly dependent on the waveguide dimensions. Finally SBS may occur due to
coupling to free modes, which exist even in the absence of acoustic
confinement; we find that the cumulative effect of coupling to these
non-confined modes results in significant SBS gain. We show how the different
acoustic properties of core and cladding lead to these different regimes, and
discuss the feasibility of SBS experiments using different material systems
Aquaculture for the poor in Cambodia
This lesson learned reviewed the current status of aquaculture in Cambodia. It primarily covers inland fish farming development and coastal aquaculture projects targeted at poverty alleviation and food security. It focuses on approaches aimed at developing low cost systems, and less on high input aquaculture systems that are usually inaccessible to poor families.
The effects of transients on photospheric and chromospheric power distributions
We have observed a quiet Sun region with the Swedish 1-meter Solar Telescope
(SST) equipped with CRISP Imaging SpectroPolarimeter. High-resolution,
high-cadence, H line scanning images were taken to observe different
layers of the solar atmosphere from the photosphere to upper chromosphere. We
study the distribution of power in different period-bands at different heights.
Power maps of the upper photosphere and the lower chromosphere show suppressed
power surrounding the magnetic-network elements, known as "magnetic shadows".
These also show enhanced power close to the photosphere, traditionally referred
to as "power halos". The interaction between acoustic waves and inclined
magnetic fields is generally believed to be responsible for these two effects.
In this study we explore if small-scale transients can influence the
distribution of power at different heights. We show that the presence of
transients, like mottles, Rapid Blueshifted Excursions (RBEs) and Rapid
Redshifted Excursions (RREs), can strongly influence the power-maps. The short
and finite lifetime of these events strongly affects all powermaps, potentially
influencing the observed power distribution. We show that Doppler-shifted
transients like RBEs and RREs that occur ubiquitously, can have a dominant
effect on the formation of the power halos in the quiet Sun. For magnetic
shadows, transients like mottles do not seem to have a significant effect in
the power suppression around 3 minutes and wave interaction may play a key role
here. Our high cadence observations reveal that flows, waves and shocks
manifest in presence of magnetic fields to form a non-linear
magnetohydrodynamic system.Comment: 11 pages, 11 Figures, 4 movies (will be available online in ApJ). ApJ
(accepted
Hydrodynamic behaviour of coal and bottom ash mixtures in a fluidized bed gasifier
systems. One of the principal applications of such systems are in combustion and gasification of solid fuels (coal, pet coke, and biomass), wherein the fuel and the inorganic residue (“ash”) form a system of binary fluidization. Even though the fluid bed gasification of coal per se is a relatively well-known operation, however the technology for high ash coal (\u3e30% ash in the native coal) is still in its nascent stage. Existing knowhow on such operations cannot predict interactions of a constantly depleting coal inventory and constantly evolving ash inventory.
With this backdrop we attempt here to study the dynamic behavior of coal and ash in a fluidized bed. In order to simulate a realistic bed composition of a gasifier, hydrodynamic characteristics were studied under various proportions of coal and ash on laboratory scale cold flow setup. A three-dimensional transient CFD model was set up to predict the dynamic and time-averaged profiles of coal and ash concentrations. The same were validated against chordal averaged solids holdup (coal and ash) characteristics measured using γ-ray densitometry, with a single collimated source (Cs-137) aligned with a scintillation NaI detector. The other part of the validation, involving the comparison of measured solids velocity profiles and CFD-predicted ones, is accomplished by implementing the Radioactive Particle Tracking (RPT) technique. In the latter technique, a single radioactive particle designed to mimic a single typical coal particle is tracked for a long time in the vessel using strategically placed scintillation detectors, and its position-time history is processed to yield the solids velocity field.
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Charge and Spin Response of the Spin--Polarized Electron Gas
The charge and spin response of a spin--polarized electron gas is
investigated including terms beyond the random phase approximation. We evaluate
the charge response, the longitudinal and transverse spin response, and the
mixed spin--charge response self--consistently in terms of the susceptibility
functions of a non--interacting system. Exchange--correlation effects between
electrons of spin and are included following Kukkonen and
Overhauser, by using spin--polarization dependent generalized Hubbard local
field factors and . The general
condition for charge--density and spin--density--wave excitations of the system
is discussed.Comment: 4 pages, latex, no figure
Certain seasonal characteristic features of oceanic heat budget components over the indian seas in relation to the summer monsoon activity over India
The present study has been undertaken to examine the oceanic heat budget components and their variability over the Indian seas in relation to the extreme monsoon activity (flood/drought) over the Indian subcontinent. For this purpose, various components of oceanic heat budget have been analysed for pre-monsoon (March-May), monsoon (June-September), post-monsoon (October-December) and winter (January-February) seasons over India. The data base used in this study consists of mean monthly marine meteorological fields for 30 years (1950-1979), which is a part of the Comprehensive Ocean Atmosphere Data Set (COADS) analysed at 1° latitude by 1° longitude resolution. The mean fields of incoming shortwave radiation flux over the Indian seas in different seasons vary in accordance to the sun's position and cloud cover variations. The latent heat flux undergoes considerable seasonal variations, particularly over the Arabian Sea. There is a dominance of latent heat flux (representing the oceanic heat loss) over shortwave solar flux (representing the oceanic heat gain) during the monsoon season, which results in a zone of net oceanic heat loss over the central Arabian Sea. This feature produces a positive feedback for the maintenance of deep cumulus convection over the Arabian Sea in this season. It is also found that oceanic heat budget components over the Indian seas exhibit significant variability in relation to the extreme monsoon activity leading to flood/drought over India. Based on the above analysis, mean monthly variations of the oceanic heat budget components over three smaller sectors of the Indian seas, namely west equatorial Indian Ocean, Arabian Sea and Bay of Bengal, are also examined. The variations are found to be considerably different between the two extreme categories of the monsoon. It becomes evident from this study that the oceanic sectors of west equatorial Indian Ocean and Bay of Bengal experience a large reduction of net heat flux from April to May prior to a flood monsoon season over India. This suggests that a spectacular increase of latent heat flux and decrease of shortwave flux occurs over these oceanic sectors, leading to a sharp reduction of net heat flux
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