29,578 research outputs found
Preliminary studies on food and feeding habits of Polypterus endlicheri and Polypterus senegalus in Lake Chad
The food and feeding habits of Polyprerus cncllicheri and Polypterus senegalus was carried out in the
months of September to October.
The food of 33 Polypierus endlicheri as observed include Tilapia species (89.3%), Eutropius niloticus
(28.6%), Mayfly nymph (39.3%), Dragon fly larva (56.6%) fish remains (21.4%) and detritus (7.1%). The
food of27 Polypterus senegalus as observed include Tilapia sp (88.4%), Eutropius niloticus (27.9%), may
fly nymph (23.3%), Dragonfly nymph (34.9%) remains (21.1%) detritus (23.3%). (9 page document)
The percentage occurrence of food item found in the stomach of Polypterus endlieheri is 93.3% while that
of Polyprerus senegalus is 67.4%. The dominance of Tilapia sp was establish in the study, and there is no
significant difference between the feeding habit of Polypterus endlicheri and Polyprerus senegalus
Development of fisheries co-management in Cambodia : a case study and its implications
The livelihoods and food security of many Cambodians depend heavily on inland capture fisheries, so the sustainable management of these fisheries is very important. Notwithstanding, the sustainability of Mekong fisheries is threatened by increasing fishing pressure and habitat modifications. Current management is considered insufficiently capable of controlling levels of exploitation and achieving equitable distribution of the resource, and the Cambodian government is promoting co-management initiatives as a way of addressing these issues. Using an institutional analysis approach, the current performance of co-management in a Mekong mainstream fishery was assessed, and factors limiting success identified. Results suggest that performance and sustainability of co-management are currently constrained by a lack of clearly defined property rights and resource boundaries, a mismatch between resource scale and management initiatives, and an absence of enabling legislation. Furthermore, objectives for management differ between stakeholders and are not well defined overall. While enabling legislation due to come into effect shortly is expected to improve performance and sustainability of co-management, boundary and scale issues will continue to pose challenges to co-management in open systems such as the Mekong mainstream. As a result, calls for innovative solutions, such as a federation of co-management schemes, will continue. In addition, increasing dependence on fishing, and external threats to resources need to be addressed if sustainability is to be improvedFishery management, Inland fisheries, Cambodia,
Testing saturation with diffractive jet production in deep inelastic scattering
We analyse the dissociation of a photon in diffractive deep inelastic
scattering in the kinematic regime where the diffractive mass is much bigger
than the photon virtuality. We consider the dominant q\bar{q}g component
keeping track of the transverse momentum of the gluon which can be measured as
a final-state jet. We show that the diffractive gluon-jet production
cross-section is strongly sensitive to unitarity constraints. In particular, in
a model with parton saturation, this cross-section is sensitive to the scale at
which unitarity effects become important, the saturation scale. We argue that
the measurement of diffractive jets at HERA in the limit of high diffractive
mass can provide useful information on the saturation regime of QCD.Comment: 12 pages, 5 figures, misprints corrected, published versio
Yukawa Matrix for the Neutrino and Lepton Flavour Violation
We estimate the magnitude of Lepton Flavour Violation (LFV) from the phase of
the neutrino Yukawa matrix. In the minimal supersymmetric standard model with
right-handed neutrinos, the LFV processes l_i \to l_j \gamma can appear through
the slepton mixing, which comes from the renormalization group effect on the
right-handed neutrino Yukawa interaction between the Grand Unified Theory scale
and the heavy right-handed neutrino mass scale. Two types of phases exist in
the neutrino Yukawa matrix. One is the Majorana phase, which can change the
magnitude of the LFV branching ratios by a few factor. The other phases relate
for the size of the Yukawa hierarchy and its phase effect can change the LFV
branching ratios by several orders of magnitude.Comment: Talk given by K. Tsumura at NuFact04, Osaka, Japan, July 26 - August
1,2004 - 3 pages, 2 figure
Design and implementation of PSO/ABC tunned PID controller for Buck converters
In the recent years, Buck converters have been widely involved in a variety of the everyday applications such as smartphones and PCs. Buck converters can provide better and steadier performance when integrating a control system in the design. Therefore, it is interesting to work on this integration and gain the required efficiency in term of the gained voltage. In this paper, PID controller is adopted to control the output voltage of the Buck converter. An optimization is achieved on the performance of the Buck converter using two bio-inspired algorithms namely, Particle Swarm Optimization (PSO) and Artificial Bee Colony (ABC). The voltage controlled Buck converter system is simulated using MATLAB environment to validate the proposed PID controller system. In this study, the voltage regulation process of Buck converter is investigated based on many working disturbances such as the change in the supply voltage, reference voltage, and load resistance in order to verify the robustness of the proposed PID controller. Finally, the feedabck voltage control system of the Buck converter is implemented experimentaly in real-time to validatde the simulated PID controller
Search for Lepton Flavor-Violating "tau -> mu gamma" decay
We search for the lepton flavor-violating "tau -> mu gamma" decay using 29.7
million tau pairs accumulated by the Belle experiment. The main background
sources are found to be tau pairs with "tau -> mu nu nu" decay and radiative
dimuon events. One event is observed in the signal region, while 2.5 +- 0.6
background events are expected. A preliminary upper limit Br(tau -> mu gamma) <
6 x 10^{-7} at the 90% confidence limit is obtained.Comment: Invited talk at the Seventh International Workshop on Tau Lepton
Physics (TAU02), Santa Cruz, Ca, USA, Sept 2002, 6 pages, LaTeX, 13 eps
figure
- …