Simulating farm income under the current soil management regime in the mid-hills of Nepal

Farmers in the mid-hills of Nepal follow diverse farming systems. The peri-urban area of this region, where population density is higher, faces several problems in farming. While hills suffer from erosion because they are erodible, the peri-urban areas face the problem of decline in factor productivity, particularly in intensively cultivated farmlands. The present study is concerned with simulating farm income on a regional scale based on soil management practices. Spatial explicit simulation shows that the loss of farm income due to degradation is substantially higher in hills while it is lower in valley bottoms. Strategy formulation and testing in the spatial environment indicates that Geographic Information System is an appropriate methodological tool for simulating the consequences of particular interventions

Free-riders or victims: women's nonparticipation in irrigation management in Nepal's Chhattis Mauja Irrigation Scheme

Irrigation managementFarmer-managed irrigation systemsIrrigation programsPrivatizationWater users' associationsIrrigated farmingIrrigation canalsWater deliveryWater allocationWater distributionMaintenanceGenderWomen in developmentFarmersFemale laborAgricultural manpowerHouseholdsFamily laborLiving standardsSocial aspectsAgricultural productionVillagesSocial organizationPerformance evaluation

Large magnetoresistance in the antiferromagnetic semi-metal NdSb

There has been considerable interest in topological semi-metals that exhibit extreme magnetoresistance (XMR). These have included materials lacking inversion symmetry such as TaAs, as well Dirac semi-metals such as Cd3As2. However, it was reported recently that LaSb and LaBi also exhibit XMR, even though the rock-salt structure of these materials has inversion symmetry, and the band-structure calculations do not show a Dirac dispersion in the bulk. Here, we present magnetoresistance and specific heat measurements on NdSb, which is isostructural with LaSb. NdSb has an antiferromagnetic groundstate, and in analogy with the lanthanum monopnictides, is expected to be a topologically non-trivial semi-metal. We show that NdSb has an XMR of 10^4 %, even within the AFM state, illustrating that XMR can occur independently of the absence of time reversal symmetry breaking in zero magnetic field. The persistence of XMR in a magnetic system offers promise of new functionality when combining topological matter with electronic correlations. We also find that in an applied magnetic field below the Neel temperature there is a first order transition, consistent with evidence from previous neutron scattering work.Comment: 5 pages, 6 figure

Gravitational trapping potential with arbitrary extra dimensions

We extend a recently discovered, non-singular 6 dimensional brane, solution to D=4+n dimensions. As with the previous 6D solution the present solution provides a gravitational trapping mechanism for fields of spin 0, 1/2, 1 and 2. There is an important distinction between 2 extra dimensions and $n$ extra dimensions that makes this more than a trivial extension. In contrast to gravity in n >2 dimensions, gravity in n=2 dimensions is conformally flat. The stress-energy tensor required by this solution has reasonable physically properties, and for n=2 and n=3 can be made to asymptotically go to zero as one moves away from the brane.Comment: 7 pages revtex. No figures. References added some discussions change

Towards inflation and dark energy cosmologies from modified Gauss-Bonnet theory

We consider a physically viable cosmological model that has a field dependent Gauss-Bonnet coupling in its effective action, in addition to a standard scalar field potential. The presence of such terms in the four dimensional effective action gives rise to several novel effects, such as a four dimensional flat Friedmann-Robertson-Walker universe undergoing a cosmic inflation at early epoch, as well as a cosmic acceleration at late times. The model predicts, during inflation, spectra of both density perturbations and gravitational waves that may fall well within the experimental bounds. Furthermore, this model provides a mechanism for reheating of the early universe, which is similar to a model with some friction terms added to the equation of motion of the scalar field, which can imitate energy transfer from the scalar field to matterComment: 35 pages, 21 eps figs; section 6 expanded improving explanations, refs added, final in JCA

Design framework:redesign and new multi-user and testing support

The use of models to conceptualize systems is an important part of the process of building Cyber Physical Systems. While designing such systems, which are in general a multi-disciplinary activity, multiple designers are involved in the design decisions. Those decisions most likely are not captured and eventually forgotten after a period. The Design Framework is a visual modeling tool that aims to help architects and designers to documents the design rationales besides the design artifacts. It also helps them to collaborate to design a system together in a multidisciplinary environment. The Design Framework is at the level of a good prototype, but it is not ready for operational application by end-users in industry. One of the main issues with the Design Framework system is a sub-optimal code structure due to the lack of proper design and development approach. The assignment therefore is to reverse engineer the current design of the Design Framework and to come up with a new design. In order to maintain a system in use, presence of a test framework is necessary. Since the Design Framework is used in a multi-disciplinary environment, an improvement in the multi-user support of the system is also needed. In the first part of this report, the redesign of the Design Framework is discussed. To redesign the Design Frame-work, a number of refactoring techniques are applied. As a result, the code complexity is reduced, therefore the maintenance is increased. The second part of the assignment includes multi-user support and testability. The Design Framework manages the changes to design descriptions and maintains the history of the design artifacts. In this respect, it operates similar to version control systems. In the multi-user part of this report, the version controlling aspect of the Design Framework is described and synchronization of data for multi-user is elaborated. Finally some multi-user features are improved and developed. In the testability part of this report, the test support is described. A set of unit tests and end-to-end tests including the test for multi-user support is implemented. Provided test sets and the approaches used to setup test environment makes the Design Framework more stable and maintainable

Late-time Cosmic Dynamics from M-theory

We consider the behaviour of the cosmological acceleration for time-dependent hyperbolic and flux compactifications of M-theory, with an exponential potential. For flat and closed cosmologies it is seen that a positive acceleration is always transient for both compactifications. For open cosmologies, both compactifications can give at late times periods of positive acceleration. As a function of proper time this acceleration has a power law decay and can be either positive, negative or oscillatory.Comment: 10 pages, LaTeX, 2 figure

The impact of tree age on biomass growth and carbon accumulation capacity: A retrospective analysis using tree ring data of three tropical tree species grown in natural forests of Suriname

The world’s forests play a pivotal role in the mitigation of global climate change. By photosynthesis they remove CO2 from the atmosphere and store carbon in their biomass. While old trees are generally acknowledged for a long carbon residence time, there is no consensus on their contribution to carbon accumulation due to a lack of long-term individual tree data. Tree ring analyses, which use anatomical differences in the annual formation of wood for dating growth zones, are a retrospective approach that provides growth patterns of individual trees over their entire lifetime. We developed time series of diameter growth and related annual carbon accumulation for 61 trees of the species Cedrela odorata L. (Meliacea), Hymenaea courbaril L. (Fabacea) and Goupia glabra Aubl. (Goupiacea). The trees grew in unmanaged tropical wet-forests of Suriname and reached ages from 84 to 255 years. Most of the trees show positive trends of diameter growth and carbon accumulation over time. For some trees we observed fluctuating growth—periods of lower growth alternate with periods of increased growth. In the last quarter of their lifetime trees accumulate on average between 39 percent (C. odorata) and 50 percent (G. glabra) of their final carbon stock. This suggests that old-growth trees in tropical forests do not only contribute to carbon stocks by long carbon resistance times, but maintain high rates of carbon accumulation at later stages of their life time

Thermodynamics and Stability of Higher Dimensional Rotating (Kerr) AdS Black Holes

We study the thermodynamic and gravitational stability of Kerr anti-de Sitter black holes in five and higher dimensions. We show, in the case of equal rotation parameters, $a_i=a$, that the Kerr-AdS background metrics become stable, both thermodynamically and gravitationally, when the rotation parameters $a_i$ take values comparable to the AdS curvature radius. In turn, a Kerr-AdS black hole can be in thermal equilibrium with the thermal radiation around it only when the rotation parameters become not significantly smaller than the AdS curvature radius. We also find with equal rotation parameters that a Kerr-AdS black hole is thermodynamically favored against the existence of a thermal AdS space, while the opposite behavior is observed in the case of a single non-zero rotation parameter. The five dimensional case is however different and also special in that there is no high temperature thermal AdS phase regardless of the choice of rotation parameters. We also verify that at fixed entropy, the temperature of a rotating black hole is always bounded above by that of a non-rotating black hole, in four and five dimensions, but not in six and more dimensions (especially, when the entropy approaches zero or the minimum of entropy does not correspond to the minimum of temperature). In this last context, the six dimensional case is marginal.Comment: 15 pages, 23 eps figures, RevTex