433 research outputs found
Working with farmers for agricultural innovation and climate adaptation
The CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS), in common with other CGIAR research programs, understands that farmers are at the centre of agricultural innovation and adaptation. This publication describes some of the many ways in which CCAFS works with farmers and farmers’ organizations to solve problems generated by climate change. Recognizing the importance of participatory knowledge systems involving farmers, scientists, and other stakeholders in responding effectively to climate change, this document seeks to provide an overview of the many ways CCAFS collaborations with farming communities work in practice – and how this can serve as a springboard for more effective dialogue and planning, leading ultimately to better outcomes for farming in a climate-constrained world
Effect of n-3 fatty acids on the antitumour effects of cytotoxic drugs
Background: n-3 fatty acids are increasingly being administered to cancer patients for the treatment of cachexia, and it is thus important to know of any potential interactions with ongoing cytotoxic drug therapy. Materials and methods: For this reason eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were administered to mice bearing the cachexia-inducing MAC16 colon adenocarcinoma, and the effect of epothilone, gemcitabine, 5-fluorouracil and cyclophosphamide on tumour growth and body weight determined. Results: Epothilone alone had a minimal effect on tumour growth rate, but this was potentiated by DHA, while for 5-fluorouracil and cyclophosphamide tumour growth inhibition was enhanced by EPA. The antitumour effect of gemcitabine was not altered by either fatty acid. EPA arrested the development of cachexia, while DHA had no effect and the same was true for their effect on tumour growth rate. The anticachectic effect of EPA was only seen in combination with 5-fluorouracil. Conclusion: These results suggest that n-3 fatty acids do not interfere with the action of chemotherapy and may potentiate the effect of certain agents
Fabrication of monodisperse poly(dl- lactic acid) microparticles using drop microfluidics
Monodisperse poly(dl-lactic acid) particles with a diameter between 11 and 121 μm were fabricated by drop microfluidics/solvent evaporation method using flow focusing glass capillary device. In the dripping regime, the ratio of droplet diameter to orifice diameter was in the range of 0.37−1.34 and was inversely proportional to the 0.39 power of the ratio of the continuous phase flow rate to dispersed phase flow rate
Fabrication of biodegradable poly(lactic acid) particles in flow focusing glass capillary devices
Fabrication of biodegradable poly(lactic acid) particles in flow focusing glass capillary device
Emulsion templating of poly(lactic acid) particles: droplet formation behavior
Monodisperse poly(dl-lactic acid) (PLA) particles of diameters between 11 and
121 ?m were fabricated in flow focusing glass microcapillary devices by evaporation of
dichloromethane (DCM) from emulsion droplets at room temperature. The dispersed phase was
5% (w/w) PLA in DCM containing 0.1−2 mM Nile red and the continuous phase was 5% (w/w)
poly(vinyl alcohol) in reverse osmosis water. Particle diameter was 2.7 times smaller than the
diameter of the emulsion droplet template indicating very low particle porosity. Monodisperse
droplets have only been produced under dripping regime using a wide range of dispersed phase
flow rates (0.002−7.2 cm3h-1), continuous phase flow rates (0.3−30 cm3h-1) and orifice diameters (50−237 ?m). In the dripping regime, the ratio of droplet diameter to orifice diameter was
inversely proportional to the 0.39 power of the ratio of the continuous phase flow rate to
dispersed phase flow rate. Highly uniform droplets with a coefficient of variation (CV) below 2
% and a ratio of the droplet diameter to orifice diameter of 0.5−1 were obtained at flow rate
ratios of 4−25. Under jetting regime, polydisperse droplets (CV > 6 %) were formed by
detachment from relatively long jets (between 4 and 10 times longer than droplet diameter) and a
ratio of the droplet size to orifice size was 2−5
Matrix Theory Interpretation of DLCQ String Worldsheets
We study the null compactification of type-IIA-string perturbation theory at
finite temperature. We prove a theorem about Riemann surfaces establishing that
the moduli spaces of infinite-momentum-frame superstring worldsheets are
identical to those of branched-cover instantons in the matrix-string model
conjectured to describe M-theory. This means that the identification of string
degrees of freedom in the matrix model proposed by Dijkgraaf, Verlinde and
Verlinde is correct and that its natural generalization produces the moduli
space of Riemann surfaces at all orders in the genus expansion.Comment: 9 pages LaTeX. Changes in style, typos correcte
Fabrication of biodegradable poly(lactic acid) particles in flow-focusing glass capillary devices
Monodisperse poly(dl-lactic acid) (PLA) particles with a diameter in the range from 12 to 100 9m were fabricated in flow focusing glass capillary devices by evaporation of dichloromethane (DCM) from emulsions at room temperature. The dispersed phase was 5% (w/w) PLA in DCM containing a small amount of Nile red and the continuous phase was 5% (w/w) poly(vinyl alcohol) in reverse osmosis water. Particle diameter was 2.7 times smaller than the size of the emulsion droplet template indicating that the particle porosity was very low. SEM images revealed that the majority of particle pores are in the sub-micron region but in some instances these pores can reach 3 9m in diameter. Droplet diameter was influenced by the flow rates of the two phases and the entry diameter of the collection capillary tube; droplet diameters decreased with increasing values of the flow rate ratio of the dispersed to continuous phase to reach constant minimum values at 40-60 % orifice diameter. At flow rate ratios less than 5, jetting can occur, giving rise to large droplets formed by detachment from relatively long jets (~10 times longer than droplet diameter)
Fuzzy Spheres in pp Wave Matrix String Theory
The behaviour of matrix string theory in the background of a type IIA pp wave
at small string coupling, g_s << 1, is determined by the combination M g_s
where M is a dimensionless parameter proportional to the strength of the
Ramond-Ramond background. For M g_s << 1, the matrix string theory is
conventional; only the degrees of freedom in the Cartan subalgebra contribute,
and the theory reduces to copies of the perturbative string. For M g_s >> 1,
the theory admits degenerate vacua representing fundamental strings blown up
into fuzzy spheres with nonzero lightcone momenta. We determine the spectrum of
small fluctuations around these vacua. Around such a vacuum all N-squared
degrees of freedom are excited with comparable energies. The spectrum of masses
has a spacing which is independent of the radius of the fuzzy sphere, in
agreement with expected behaviour of continuum giant gravitons. Furthermore,
for fuzzy spheres characterized by reducible representations of SU(2) and
vanishing Wilson lines, the boundary conditions on the field are characterized
by a set of continuous angles which shows that generically the blown up strings
do not ``close''.Comment: 45 pages REVTeX 4 and AMSLaTeX. 1 figure. v2: references added.
Figure redrawn using LaTe
Constraints on a Massive Dirac Neutrino Model
We examine constraints on a simple neutrino model in which there are three
massless and three massive Dirac neutrinos and in which the left handed
neutrinos are linear combinations of doublet and singlet neutrinos. We examine
constraints from direct decays into heavy neutrinos, indirect effects on
electroweak parameters, and flavor changing processes. We combine these
constraints to examine the allowed mass range for the heavy neutrinos of each
of the three generations.Comment: latex, 29 pages, 7 figures (not included), MIT-CTP-221
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