Suitable Contraction Research Articles

SHARECROPPING, LAND EXPLOITATION AND LAND-IMPROVING INVESTMENTS*

This paper analyses the tenancy problem in a dynamic setup and addresses two long-standing issues: inefficiency and lack of investment. It considers the problems that the tenant, with a shorter-term interest in the farm than the landlord, might overexploit the land to maximize immediate returns even at the cost of future damages, and under-supply long-run productivity improving investments in land. I show that the efficient (first-best) levels of input use and investment can be achieved (both in the steady state and in transition) by a suitable share contract which, by dampening incentives to maximize current returns, addresses the land exploitation problem, and by an appropriate cost allocation rule which can address the investment problem.

Generalized gravitational S-duality and the cosmological constant problem

We study S-duality transformations that mix the Riemann tensor with the field strength of a 3-form field. The dual of an (A)dS spacetime—with arbitrary curvature—is seen to be flat Minkowski spacetime if the 3-form field has vanishing field strength before the duality transformation. It is discussed whether matter could couple to the dual metric, related to the Riemann tensor after a duality transformation. This possibility is supported by the facts that the Schwarzschild metric can be obtained as a suitable contraction of the dual of a Taub-NUT-AdS metric, and that metrics describing FRW cosmologies can be obtained as duals of theories with matter in the form of torsion.

Group preserving scheme for backward heat conduction problems

In this paper we numerically integrate the backward heat conduction equation ∂ u/∂ t= ν▵ u, in which the Dirichlet boundary conditions are specified at the boundary of a certain spatial domain and a final data is specified at time T>0. In order to treat this ill-posed problem we first convert it through the transformation s= T− t to an unstable initial-boundary-value problem: ∂ u/∂ s=− ν▵ u together with the same boundary conditions and the same data at s=0. Then, we consider the contraction map of u to v=exp[− as] u by a suitable contraction factor a>0, which is analyzed by considering the stability of the semi-discretization numerical schemes. The resulting ordinary differential equations at the interior grid points are then numerically integrated by the group preserving scheme, proposed by Liu [Int. J. Non-Linear Mech. 36 (2001) 1047], and the stable range of the index r= νΔ t/(Δ x) 2 is derived. Numerical tests for both forward and backward heat conduction problems are performed to confirm the effectiveness of the new numerical methods.

Pitfalls to avoid in providing accommodation for staff

MANY veterinary practices choose to offer some form of accommodation to certain members of their staff, as there are advantages to both the employee and the practice in this arrangement....

Nonlinear Markov semigroups, nonlinear Dirichlet forms and applications to minimal surfaces

We introduce the notions of nonlinear Markov semigroups and nonlinear Dirichlet forms on a Hilbert space L 2 ðX ; mÞ. Dirichlet forms are meant to be convex lower semicontinuous functionals on L 2 ðX ; mÞ, enjoying contraction properties w.r.t. projections onto suitable closed and convex sets. We prove the one-to-one correspondence between these two classes of objects, by establishing Beurling-Deny-like criteria which characterize separately the non-expansion in L y ðX ; mÞ and the order preserving properties of the semi- group. G-limits of functionals enjoying the suitable contraction properties are nonlinear Dirichlet forms, and in particular this holds for relaxed functionals. Examples include elliptic, subelliptic and subriemannian p-Laplacians on Riemannian manifolds, possibly with measurable, non necessarily uniformly elliptic coe‰cients, nonlinear operators con- structed from derivations in Hilbert C � -modules, and convex functionals of the gradient including the area and the perimeter functionals. We apply the theory to construct Markov evolutions which approach minimal surfaces with given boundary contour, as well as Markov evolutions which converge to the solution of a Dirichlet problem with given boundary data.

Briefing: NEC and local government procurement

The NEC Engineering and Construction Contract (ECC) provides a sound basis from which to develop a suitable contract by which local government can procure works and services. The underlying principles of the ECC, as stated in the first condition, seek to promote mutual trust and co-operation for the benefit of the parties and the project. These principles fit well with the increasingly onerous procurement obligations being placed on local government by statute.

NEC and local government procurement

The NEC Engineering and Construction Contract (ECC) provides a sound basis from which to develop a suitable contract by which local government can procure works and services. The underlying principles of the ECC, as stated in the first condition, seek to promote mutual trust and co-operation for the benefit of the parties and the project. These principles fit well with the increasingly onerous procurement obligations being placed on local government by statute.

Sprinkler Performance as Function of Nozzle Geometrical Parameters

The main design parameter for a square nozzle is its inside contraction angle, and key design parameters for a triangular nozzle include the inside contraction angle and the length-to-width ratio of the triangular orifice. The variation of discharge coefficient, pattern radii, and uniformity of water application as a function of the parameters previously mentioned were studied. For a square nozzle, both the discharge coefficient and the pattern radius decreased with increasing inside contraction angle when the angle exceeded 50°. The suitable inside contraction angle is around 30°. For a triangular nozzle, the influence of the inside contraction angle on its discharge coefficient and water application was insignificant for an angle range of 10°–45°, but the water application profiles from a single sprinkler were sensitive to the orifice height-to-width ratio. A 1.00 height-to-width ratio nozzle discharges more water near the sprinkler and yields a higher uniformity coefficient than other ratio nozzles for a given sprinkler pressure and spacing.

Real forms of Uq(OSp(1/2)) and quantum D=2 supersymmetry algebras

The authors present three real forms of quantum superalgebra Uq(OSp(1/2)). By defining suitable contraction limits they describe the q-deformations of D=2 superPoincare and D=2 superEuclidean algebras as Hopf bialgebras.

Free-field formulation of topological supergravity

Two-dimensional topological supergravity is taken to be defined by topological OSP(2, 1) Yang-Mills gauge theory. A free-field formulation is achieved by choosing a suitable contraction of the gauge group. This formulation enables us to represent explicitly the complete det of BRST invariant local operators. Because of an inadequate understanding of supermoduli space, the physical content of the theory remains to be fully explored.

India's oil policy: To import crudes or products?

India will remain a net oil importer in the foreseeable future and any additional refining capacity will run essentially on imported crudes. However, self-sufficiency in infigenous refining capability would not necessarily be the least-cost option. Demand for refined products in India, their prices in the international market and quality of crude oils available for import are among the major factors that will influence refinery investment decisions. It may be worthwhile negotiating a suitable petroleum products procurement contract with product-surplus nations in the region. Negotiating such a contract may be easier if oil demand management measures are also implemented successfully.

Irreducible tensor description. III. Thermodynamics of a low-temperature phonon gas

Let one assume that the interacting phonon gas, whose behavior is governed by the Boltzmann–Peierls equation, inhabits an insulating crystal at sufficiently low temperature. Then, within the framework of a single acoustic phonon branch and of an isotropic long-wavelength approximation to the dispersion relation, the simplest acceptable version of extended irreversible thermodynamics, based upon the nine-moment system of differential equations for the slow and fast gas-state variables, is carefully investigated. It is clearly demonstrated that, in virtue of the structure simplifications just mentioned, the conceptually different (macroscopic, kinetic, and variational) procedures, which are discussed in this paper, appear complementary to each other. Finally, with the help of a suitable contraction of the nine-moment system of field equations, for Callaway’s relaxation model a slightly generalized nonlinear variant of ordinary low-temperature phonon hydrodynamics is explicitly derived.

India's oil policy: The dilemma for self-sufficiency in refining capability

India is likely to be a net oil importer in the foreseeable future and any additional refining capacity will run essentially on imported crudes. It is not clear that self-sufficiency in indigenous refining capability will be the least-cost option. Product price levels in the international market and quality of crude oils available for import are among the major factors that will influence refinery-investment decisions. It may be desirable for India to negotiate a suitable petroleum products procurement contract with productsurplus nations in the region.

Effects of Halothane and Isoflurane on Isolated Human Ventricular Myocardium

Segments of viable human left ventricular trabeculae were obtained at the time of endocardial resection for intractable ventricular ectopy. Muscle segments which showed suitable and reproducible contractions in 26 mM K Tyrode solution with 1 microM isoproterenol were electrically stimulated after rest, and at frequencies of 0.1, 0.25, 0.5, and 1 Hz. Effects of 0.75% halothane and 1.3% isoflurane on peak tension, maximum rate of tension development (dT/dt-max), and on slow (calcium dependent) action potential (AP) characteristics were studied. Halothane depressed peak tension, dT/dt-max, and slow AP maximum rate of depolarization (Vmax) at all frequencies, and caused a significantly greater depression of peak tension and dT/dt-max at 0.5-1 Hz than after rest and at 0.1-0.25 Hz. Isoflurane did not significantly depress slow AP Vmax, showed no frequency dependent contractile depression, and depressed dT/dt-max less than halothane at 0.5 and 1 Hz. Halothane and isoflurane caused differing depression in the pattern of developed tension. The differential depression by halothane and isoflurane of human ventricular myocardium was similar to that previously observed in isolated animal ventricular tissue.

Towards a valence‐orbital/bond‐orbital description of biochemical H‐bonds from ab initio calculations

AbstractWe have studied the system NH3…H+…HNCH‐CHCH2, which is a model for an enzymatic site characterized by an important pi‐electron contribution, with the aim of contributing to the molecular orbital theory of H‐bridge formation and proton transfer. Ab initio canonical orbitals from STO‐3G and 4.31G bases have been determined for various geometrical configurations, and analyzed in terms of Mulliken's Modified Valence Atomic Orbitals obtained by suitable contraction. Also, the orbital correlation diagram has been obtained and discussed. At least two sigma MO's can be considered specific of the H‐bond: they involve the expected hybrids giving rise to stereoelectronic effects associated with the lone pairs of the two heavy atoms. Population analysis suggests that the bridge hydrogen changes its population very little during its motion along the bridge, although its in situ atomic orbital does not change: this means that it acts essentially as a relay center in charge transfer between the two moieties of the H‐bonded complex. As expected on intuitive grounds, charge transfer involves essentially the sigma cores.

Geometric origin of central charges

The complete set of N(N-1) central charge generators for the D=4 N-extended super-Poincare algebra is obtained by suitable contraction of the OSp(2N;4) superalgebra. The superspace realisations of the spinorial generators with central charges are derived. The conjugate set of N(N-1) additional bosonic superspace coordinates is introduced in a unique and geometric way.

On Decentralized Control with Overlapping Information Sets

A decentralized control scheme is proposed for linear systems composed of overlapping subsystems. By expanding the state space of the system, a higher dimensional space is formed where the subsystems appear as disjoint. In the expanded space, standard optimization techniques can be used to formulate a sub optimal decentralized control law for the overall system. A suitable contraction of the obtained control law, which is compatible with the overlapping information constraint, can be implemented in the original system

Decentralized control with overlapping information sets

A decentralized control scheme is proposed for linear systems composed of overlapping subsystems. By expanding the state space of the system, a higher-dimensional space is formed where the subsystems appear as disjoint. In the expanded space, standard optimization techniques can be used to formulate a suboptimal decentralized control law for the overall system. A suitable contraction of the obtained control law, which is compatible with the information constraints imposed by the overlapping subsystems, can be implemented in the original system. The application of the proposed decentralized control scheme is illustrated using a 19th order model for load-frequency control of a two-area interconnected power system.

The relevance of antenatal and intrapartum fetal heart rate patterns to fetal outcome.

Antenatal fetal heart rate (FHR) as an indicator of fetal status was evaluated in two separate studies. The first attempted to determine, in 30 minutes of continuous recording from each of 50 antenatal patients, relationships between spontaneous FHR changes and fetal condition before and after birth. No significant association was found between observed FHR patterns and antenatal or neonatal fetal status. The second study used induction of labour as a stress test, because similar conditions to that required for oxytocin stress testing were present and there was the advantage of direct FHR recording. In 150 induced and monitored labours, FHR changes associated with the first six suitable contractions seldom related to Apgar scores at birth or development of fetal distress in active labour. Fetuses showing no response to contractions tended to have better Apgar scores than those which showed FHR decelerations. Results from these studies do not substantiate reports that FHR changes arising spontaneously, or in response to induced contractions, reflect satisfactorily the existing or subsequent fetal status.

Soft X-Ray Emission in Metals

A general quantum-mechanical many-body treatment of soft x-ray emission in metals is presented. By considering the initial state of the system to be created by removing an electron from the ground state of an $N$-electron system, the energy-dependent emission intensity is related to a suitable contraction of the three-particle Green's function based on the $N$-particle ground state. While the formalism includes fully all electron-electron interactions, the main concern in this paper is with the effect of the x-ray vacancy on the surrounding electron gas. This is accounted for partially by summing a selected set of ladder graphs describing the repeated scatterings of an incident conduction electron on the vacancy. The formula for the intensity obtained in this way is similar to that for noninteracting particles except that a correlated wave function for the electron-hole pair replaces the usual product of two independent-particle wave functions. In the limit when the initial vacancy is assumed to act as a fixed heavy impurity center, our expressions reduce correctly to the square of a dipole-moment matrix element between the vacancy wave function and that for a conduction electron in the Hartree field of the impurity.