The Social Importance and Continuity of Falaj Use in Northern Oman

Oman has an arid climate with an annual average rainfall less than 100 mm. Agriculture production in Oman is almost fully dependent on irrigation in which more than one third of irrigation water is supplied by aflāj. Prior to the 1970s, falaj (singular of aflāj) systems were the backbone of agriculture in the northern parts of Oman. There are three types of falaj in Oman: ghailī, da'ūdī and cainī. Among these three types, only the da'ūdī falaj is similar to the qanat irrigation systems of Iran. Aflāj are conduits dug in the ground to convey water by gravity from one place to another; there are more than 4,000 aflāj in the Sultanate of Oman, of which 3,017 are active. Many aflāj in Oman were built over 1,500 years ago and some of them may date back over 2,500 years. There was a major period of construction during the Yacāriba Dynasty, by Imam Sultan bin Saif Al Yarubi between 1,060 and 1,070 Hijri (1,650- 1,660 AD). However, several aflāj were constructed only 150 years ago. The falaj systems are still focal to agricultural communities in Oman as they represent 36% of the total water consumed in the agricultural sector and 38% of the total available fresh water. Because of their historical and cultural importance, five representative falaj systems, together with associated structures such as defensive towers, mosques sundials and buildings for water auctions, have recently been designated as a UNESCO World Heritage site. Sustainability was the way of life of our ancestors: because falaj systems use gravity flow, water use never exceeded water supply. The Sultanate's traditional methods of water management provide important lessons for the future. Using water fairly in times of plenty and times of scarcity is one of these lessons. Matching water use to water availability, a fundamental characteristic of the falaj system, is an essential element in planning water management in Oman's climatic conditions.The Iranian National Committee on Irrigation and Drainage (IRNCID); The International Commission on Irrigation and Drainage (ICID); The International Network on Participatory Irrigation Management (INPIM

Enhancing structure relaxations for first-principles codes: an approximate Hessian approach

We present a method for improving the speed of geometry relaxation by using a harmonic approximation for the interaction potential between nearest neighbor atoms to construct an initial Hessian estimate. The model is quite robust, and yields approximately a 30% or better reduction in the number of calculations compared to an optimized diagonal initialization. Convergence with this initializer approaches the speed of a converged BFGS Hessian, therefore it is close to the best that can be achieved. Hessian preconditioning is discussed, and it is found that a compromise between an average condition number and a narrow distribution in eigenvalues produces the best optimization.Comment: 9 pages, 3 figures, added references, expanded optimization sectio

Relative entropy in 2d Quantum Field Theory, finite-size corrections and irreversibility of the Renormalization Group

The relative entropy in two-dimensional Field Theory is studied for its application as an irreversible quantity under the Renormalization Group, relying on a general monotonicity theorem for that quantity previously established. In the cylinder geometry, interpreted as finite-temperature field theory, one can define from the relative entropy a monotonic quantity similar to Zamolodchikov's c function. On the other hand, the one-dimensional quantum thermodynamic entropy also leads to a monotonic quantity, with different properties. The relation of thermodynamic quantities with the complex components of the stress tensor is also established and hence the entropic c theorems are proposed as analogues of Zamolodchikov's c theorem for the cylinder geometry.Comment: 5 pages, Latex file, revtex, reorganized to best show the generality of the results, version to appear in Phys. Rev. Let

Point-of-care screening for a current Hepatitis C virus infection: influence on uptake of a concomitant offer of HIV screening

Eliminating hepatitis C as a public health threat requires an improved understanding of how to increase testing uptake. We piloted point-of-care testing (POCT) for a current HCV infection in an inner-city Emergency Department (ED) and assessed the influence on uptake of offering concomitant screening for HIV. Over four months, all adults attending ED with minor injuries were first invited to complete an anonymous questionnaire then invited to test in alternating cycles offering HCV POCT or HCV+HIV POCT. Viral RNA was detected in finger-prick blood by GeneXpert. 814/859 (94.8%) questionnaires were returned and 324/814 (39.8%) tests were accepted, comprising 211 HCV tests and 113 HCV+HIV tests. Offering concomitant HIV screening reduced uptake after adjusting for age and previous HCV testing (odds ratio 0.51; 95% confidence interval [CI] 0.38–0.68; p < 0.001). HCV prevalence was 1/324 (0.31%; 95% CI 0.05–1.73); no participant tested positive for HIV. 167/297 (56.2%) POCT participants lived in the most deprived neighbourhoods in England. HCV RNA testing using finger-prick blood was technically feasible. Uptake was moderate and the offer of concomitant HIV screening showed a detrimental impact on acceptability in this low prevalence population. The findings should be confirmed in a variety of other community settings

Phytoremediation of Nutrients and Organic Carbon from Sago Mill Effluent using Water Hyacinth (Eichhornia crassipes)

The aim of this study was to investigate the ability of floating water hyacinth (Eichhornia crassipes) to survive under selected concentrations of sago mill effluent (SME) and determine the nutrient uptake by the plant. Phytoremediation at 10, 15, and 20% (VSME/Vwater) SME concentrations by water hyacinth was conducted under greenhouse conditions for 30 d in a batch type experiment. After 30 d of phytoremediation, the removal efficiency of chemical oxygen demand, ammonia and phosphorus from SME wastewater were (86.4% to 97.2%), (91.4% to 97.3%) and (80.4 to 97.2%), respectively. The results proved the efficiency of water hyacinth to polish SME wastewater

Chromatin jets define the properties of cohesin-driven in vivo loop extrusion

Complex genomes show intricate organization in three-dimensional (3D) nuclear space. Current models posit that cohesin extrudes loops to form self-interacting domains delimited by the DNA binding protein CTCF. Here, we describe and quantitatively characterize cohesin-propelled, jet-like chromatin contacts as landmarks of loop extrusion in quiescent mammalian lymphocytes. Experimental observations and polymer simulations indicate that narrow origins of loop extrusion favor jet formation. Unless constrained by CTCF, jets propagate symmetrically for 1-2 Mb, providing an estimate for the range of in vivo loop extrusion. Asymmetric CTCF binding deflects the angle of jet propagation as experimental evidence that cohesin-mediated loop extrusion can switch from bi- to unidirectional and is controlled independently in both directions. These data offer new insights into the physiological behavior of in vivo cohesin-mediated loop extrusion and further our understanding of the principles that underlie genome organization

Synthesis of (+)-(R)-Tiruchanduramine

The absolute stereochemistry of the marine alkaloid (+)-(R)-tiruchanduramine was established via a convergent total synthesis in six steps and 15.5% overall yield from Fmoc-D-Dab(Boc)-OH