Managing irrigation jointly with farmers: history, present status and future: review of participatory irrigation management in Sri Lanka

Agriculture development has been the main strategy for the socioeconomic development in the country since time immemorial, even though its contribution to GDP has been declining recently. Successive governments of Sri Lanka since independence have invested heavily in the irrigated agriculture sector to address the food security concerns of the country. The continuous investment in irrigation was required to address problems such as spatial and temporal variations in monsoonal rainfall in the country, which has a serious negative impact on food production and livelihoods of people. The need for pursuing irrigation development and management has become more important in the country in the face of rapid population growth and increasing food prices in the world market. In this context, managing irrigation schemes for productivity increase is becoming increasingly important and different irrigation management models have also emerged through attempts made in this direction by countries including Sri Lanka, where irrigation plays a leading role in food production and nation development. Farmers’ active involvement in irrigation management, especially operation and maintenance (O&M) and decision-making as well, has been identified as a key requirement to attain productivity goals and the sustainability of irrigation systems. This paper aims at reviewing participatory irrigation management approaches adopted in medium and major irrigation systems in Sri Lanka with a view to identifying their past and present trends and future directions. The review will contribute to an improved understanding by policymakers, managers of irrigation schemes and farmers of the role of participatory irrigation management, its past and present including institutional structures, responsibilities and performance and the directions it should take to meet future challenges as a dynamic institutional mechanism. As all the medium and major irrigation schemes in the country are jointly managed by farmers and government agencies, the inferences drawn from the review would be important for the agencies and farmers alike to introduce necessary changes in their programs to address future needs and requirements.Length: pp.35-63Participatory managementIrrigation managementFarmers organizationsIndicatorsHistoryIrrigation schemes

Perubahan Kadar Hormon Tiroid pada Penderita Sindroma Nefrotik

Thyroid hormones levels in nephrotic syndromeBackground: Nephrotic syndrome is one of the most found kidney disease. A great part (>99%) of circulating thyroid hormones were bound to proteins, thus derangements of blood proteins in nephrotic syndrome are potential to disturb thyroid hormones levels. This study was aimed to compare thyroid hormones levels changes in childhood Nephrotic Syndrome before and after remission.Method: Thirty four nephrotic syndrome patients studied on Department of pediatric of Dr. Kariadi Hospital, Semarang between April 1995 to June 1996 were for albumin, cholesterol, thyroid and thyroid stimulating hormone levels before and after remission and were tested with Wilcoxon signed rank test. The correlation between albumin and thyroxin levels before and after remission. were analyzed with Spearman correlation test.Results: T4 level before remission was 26.89±16.12 nmol/L, TSH 9.36±5.51 IU/ml, and after remission T4 106.63±28.02 nmol/L,TSH 1.78±1.91 μIU/mL. There were significant changes of thyroid hormones levels before and after remission (z=5.09; p=0.000). There were positive correlation between blood protein (albumin) level and thyroid hormone (T4) level in nephrotic syndrome before remission (r=0.51; p=0.000) and after remission (r=0.38; p=0.004). A great proportion of nephrotic syndrome patients, suffered from hypothyroidism and return to euthyroid after remission.Conclusions: Thyroid hormone levels changed during the course of nephrotic syndrome

An assessment of the Small-Scale Irrigation Management Turnover Program in Indonesia.

Irrigation management / Privatization / Small scale systems / Irrigation systems / Water distribution / Performance / Operations / Maintenance / Productivity / Crop yield / Economic impact / Costs / Indonesia

On the Production of π+π+\pi^+\pi^+ Pairs in pp Collisions at 0.8 GeV

Data accumulated recently for the exclusive measurement of the $pp\to pp\pi^+\pi^-$ reaction at a beam energy of 0.793 GeV using the COSY-TOF spectrometer have been analyzed with respect to possible events from the $pp \to nn\pi^+\pi^+$ reaction channel. The latter is expected to be the only $\pi\pi$ production channel, which contains no major contributions from resonance excitation close to threshold and hence should be a good testing ground for chiral dynamics in the $\pi\pi$ production process. No single event has been found, which meets all conditions for being a candidate for the $pp \to nn \pi^+\pi^+$ reaction. This gives an upper limit for the cross section of 0.16 $\mu$b (90% C.L.), which is more than an order of magnitude smaller than the cross sections of the other two-pion production channels at the same incident energy

Aging of the Nonlinear Optical Susceptibility of colloidal solutions

Using Z-scan and dynamic light scattering measurements we investigate the nonlinear optics response of a colloidal solution undergoing dynamics slowing down with age. We study the high optical nonlinearity of an organic dye (Rhodamine B) dispersed in a water-clay (Laponite) solution, at different clay concentrations (2.0 wt% - 2.6 wt%), experiencing the gelation process. We determine the clay platelets self diffusion coefficient and, by its comparison with the structural relaxation time, we conclude that the gelation process proceeds through the structuring of interconnecting clay platelets network rather than through clusters growth and aggregation.Comment: 4 figures, 4 page

Effect of Somatic Cell Types and Culture Medium on in vitro Maturation, Fertilization and Early Development Capability of Buffalo Oocytes

This study was designed to evaluate the efficacy of different somatic cell types and media in supporting in vitro maturation (IVM), in vitro fertilization (IVF) and early embryonic development competence of buffalo follicular oocytes. Cumulus oocyte complexes were collected for maturation from follicles (>6mm) of buffalo ovaries collected at the local abattoir. Oocytes were co-cultured in tissue culture medium (TCM-199) with either granulosa cells, cumulus cells, or buffalo oviductal epithelial cells (BOEC) @ 3x106 cells/ml or in TCM-199 without helper cells (control) at 39°C and 5%CO2 in humidified air. Fresh semen was prepared in modified Ca++ free Tyrode medium. Fertilization was carried out in four types of media: i) Tyrode lactate albumin pyruvate (TALP), ii) TALP+BOEC, iii) modified Ca++ free Tyrode and iv) modified Ca++ free Tyrode+BOEC. Fertilized oocytes were cultured for early embryonic development in TCM-199 with and without BOEC. Higher maturation rates were observed in the granulosa (84.24%) and cumulus cells (83.44%) than BOEC co culture system (73.37%). Highest fertilization rate was obtained in modified Ca++ free Tyrode with BOEC co culture (70.42%), followed by modified Ca++ free Tyrode alone (63.77%), TALP with BOEC (36.92%) and TALP alone (10.94%). Development of early embryos (8-cell stage) improved in TCM-199 with BOEC co culture than TCM-199 alone. From the results of this study, it can be concluded that addition of somatic cells (granulosa cells, cumulus cells) results in higher maturation rates of buffalo follicular oocytes than BOEC co culture system, while fertilization rate improved in modified Ca++ free Tyrode with and without BOEC. Addition of BOEC to TCM-199 improved the developmental capacity of early embryo

Strong negative self regulation of Prokaryotic transcription factors increases the intrinsic noise of protein expression

Background Many prokaryotic transcription factors repress their own transcription. It is often asserted that such regulation enables a cell to homeostatically maintain protein abundance. We explore the role of negative self regulation of transcription in regulating the variability of protein abundance using a variety of stochastic modeling techniques. Results We undertake a novel analysis of a classic model for negative self regulation. We demonstrate that, with standard approximations, protein variance relative to its mean should be independent of repressor strength in a physiological range. Consequently, in that range, the coefficient of variation would increase with repressor strength. However, stochastic computer simulations demonstrate that there is a greater increase in noise associated with strong repressors than predicted by theory. The discrepancies between the mathematical analysis and computer simulations arise because with strong repressors the approximation that leads to Michaelis-Menten-like hyperbolic repression terms ceases to be valid. Because we observe that strong negative feedback increases variability and so is unlikely to be a mechanism for noise control, we suggest instead that negative feedback is evolutionarily favoured because it allows the cell to minimize mRNA usage. To test this, we used in silico evolution to demonstrate that while negative feedback can achieve only a modest improvement in protein noise reduction compared with the unregulated system, it can achieve good improvement in protein response times and very substantial improvement in reducing mRNA levels. Conclusions Strong negative self regulation of transcription may not always be a mechanism for homeostatic control of protein abundance, but instead might be evolutionarily favoured as a mechanism to limit the use of mRNA. The use of hyperbolic terms derived from quasi-steady-state approximation should also be avoided in the analysis of stochastic models with strong repressors

Systematic study of the pp -> pp omega reaction

A systematic study of the production of omega-mesons in proton-proton-collisions was carried out in a kinematically complete experiment at three excess energies(epsilon= 92, 128, 173MeV). Both protons were detected using the large-acceptance COSY-TOF spectrometer at an external beam line at the Cooler Synchrotron COSY at Forschungszentrum J\"ulich. The total cross section, angular distributions of both omega-mesons and protons were measured and presented in various reference frames such as the overall CMS, helicity and Jackson frame. In addition, the orientation of the omega-spin and invariant mass spectra were determined. We observe omega-production to take place dominantly in Ss and Sp final states at epsilon = 92, 128 MeV and, additionally, in Sd at epsilon= 173 MeV. No obvious indication of resonant omega-production via N^*-resonances was found, as proton angular distributions are almost isotropic and invariant mass spectra are compatible with phase space distributions. A dominant role of ^3P_1 and ^1S_0 initial partial waves for omega-production was concluded from the orientation of the decay plane of the omega-meson. Although the Jackson angle distributions in the omega-p-Jackson frame are anisotropic we argue that this is not an indication of a resonance but rather a kinematical effect reflecting the anisotropy of the omega angular distribution. The helicity angle distribution in the omega-p-helicity frame shows an anisotropy which probably reflects effects of the omega angular momenta in the final state; this observable may be, in addition to the orientation of the omega decay plane, the most sensitive one to judge the validity of theoretical descriptions of the production process.Comment: 17 pages, 16 figures, accepted for publication in EPJ

The study of the negative pion production in neutron-proton collisions at beam momenta below 1.8 GeV/c

A detailed investigation of the reaction np -> pp\pi^{-} has been carried out using the data obtained with the continuous neutron beam produced by charge exchange scattering of protons off a deuterium target. A partial wave event-by-event based maximum likelihood analysis was applied to determine contributions of different partial waves to the pion production process. The combined analysis of the np -> pp\pi^{-} and pp -> pp\pi^{0} data measured in the same energy region allows us to determine the contribution of isoscalar partial waves (I=0) in the momentum range from 1.1 up to 1.8 GeV/c. The decay of isoscalar partial waves into (^1S_0)_{pp}\pi$ channel provides a good tool for a determination of the pp S-wave scalar scattering length in the final state which was found to be a_{pp}=-7.5\pm 0.3 fm.Comment: 6 pages, 6 figure

Measurement of the Eta Production in Proton Proton Collisions with the COSY Time of Flight Spectrometer

The reaction pp -> pp eta was measured at excess energies of 15 and 41 MeV at an external target of the Juelich Cooler Synchrotron COSY with the Time of Flight Spectrometer. About 25000 events were measured for the excess energy of 15 MeV and about 8000 for 41 MeV. Both protons of the process pp eta were detected with an acceptance of nearly 100% and the eta was reconstructed by the missing mass technique. For both excess energies the angular distributions are found to be nearly isotropic. In the invariant mass distributions strong deviations from the pure phase space distributions are seen.Comment: 15 pages, 14 figures, 4 table