The Mineral Content Of Prairie Grasses Within A Five Mile Radius Of Prairie View College

Of all the plants of the earth the grasses are of the greatest use to the human race. To the grasses belong tie cereals, sugar cane, sorghum, and the bamboos; and, since they furnish the bulk of forage for domestic animals, the grasses are also the basis of animal industry. The grasses furnish the principal breadstuffs of the world and a large part of the food for domestic animals. (8) In Texas the dominant grass over many of the prairies is curly mesquite (Hilaria Belangeri) (6), a dod-former, similar to Buffalo grass and Bermuda. It is of interest to consider briefly the calcium and phosphorus contents of various species of herbage in relation to mineral requirements of grazing animals. Archibald and Bennett (12) concluded after a review of the literature, that 0.15% of phosphorus in the herbage is the lower limit of safety, below which point the deficiency may seriously lower the value of the pasture for grazing purposes

Matching Kasteleyn Cities for Spin Glass Ground States

As spin glass materials have extremely slow dynamics, devious numerical methods are needed to study low-temperature states. A simple and fast optimization version of the classical Kasteleyn treatment of the Ising model is described and applied to two-dimensional Ising spin glasses. The algorithm combines the Pfaffian and matching approaches to directly strip droplet excitations from an excited state. Extended ground states in Ising spin glasses on a torus, which are optimized over all boundary conditions, are used to compute precise values for ground state energy densities.Comment: 4 pages, 2 figures; minor clarification

A Unified Approach to Attractor Reconstruction

In the analysis of complex, nonlinear time series, scientists in a variety of disciplines have relied on a time delayed embedding of their data, i.e. attractor reconstruction. The process has focused primarily on heuristic and empirical arguments for selection of the key embedding parameters, delay and embedding dimension. This approach has left several long-standing, but common problems unresolved in which the standard approaches produce inferior results or give no guidance at all. We view the current reconstruction process as unnecessarily broken into separate problems. We propose an alternative approach that views the problem of choosing all embedding parameters as being one and the same problem addressable using a single statistical test formulated directly from the reconstruction theorems. This allows for varying time delays appropriate to the data and simultaneously helps decide on embedding dimension. A second new statistic, undersampling, acts as a check against overly long time delays and overly large embedding dimension. Our approach is more flexible than those currently used, but is more directly connected with the mathematical requirements of embedding. In addition, the statistics developed guide the user by allowing optimization and warning when embedding parameters are chosen beyond what the data can support. We demonstrate our approach on uni- and multivariate data, data possessing multiple time scales, and chaotic data. This unified approach resolves all the main issues in attractor reconstruction.Comment: 22 pages, revised version as submitted to CHAOS. Manuscript is currently under review. 4 Figures, 31 reference

Reply to Comment on "Triviality of the Ground State Structure in Ising Spin Glasses"

We reply to the comment of Marinari and Parisi [cond-mat/0002457 v2] on our paper [Phys. Rev. Lett. 83, 5126 (1999) and cond-mat/9906323]. We show that the data in the comment are affected by strong finite-size corrections. Therefore the original conclusion of our paper still stands.Comment: Reply to comment cond-mat/0002457 on cond-mat/9906323. Final version with minor change

Effect of wind on continental shelf carbon fluxes off southeast Australia: A numerical model

A coupled physical-biological-chemical model is used to study the effect of upwelling-favorable and downwelling-favorable winds on carbon biogeochemistry on the continental shelf off the southeast Australian mainland. Along the continental shelf, from 30?S to 34?S, upwelling-favorable winds, with the aid of bottom Ekman transport, bring dissolved-inorganic-carbon (DIC)-rich slope waters onto the shelf, increasing the carbon held in shelf waters. For downwelling-favorable winds, bottom Ekman transport still lifts slope waters onto the shelf, but the slope water transport, and therefore carbon held, is reduced compared with the upwelling scenario. Under upwelling-favorable winds, filaments of DIC and dissolved-inorganic-nitrogen (DIN)-rich water reaching the surface produce an outgassing near the site of upwelling and absorption downstream due to primary productivity. In a region of the ocean that is generally absorbing, the net effect of upwelling is a reduced absorption of atmospheric CO2 as a result of the ratio of deep DIC and DIN (12.2:1 mol C:mol N) being greater than the Redfield ratio (6.625). Carbon fluxes in the waters off the southeast Australian mainland are variable in space, with the transport of continental shelf waters to deep waters occurring mainly where alongshore currents separate from the coast and flow over the 200-m isobath

Collective Transport in Arrays of Quantum Dots

(WORDS: QUANTUM DOTS, COLLECTIVE TRANSPORT, PHYSICAL EXAMPLE OF KPZ) Collective charge transport is studied in one- and two-dimensional arrays of small normal-metal dots separated by tunnel barriers. At temperatures well below the charging energy of a dot, disorder leads to a threshold for conduction which grows linearly with the size of the array. For short-ranged interactions, one of the correlation length exponents near threshold is found from a novel argument based on interface growth. The dynamical exponent for the current above threshold is also predicted analytically, and the requirements for its experimental observation are described.Comment: 12 pages, 3 postscript files included, REVTEX v2, (also available by anonymous FTP from external.nj.nec.com, in directory /pub/alan/dotarrays [as separate files]) [replacement: FIX OF WRONG VERSION, BAD SHAR] March 17, 1993, NEC

Percolation of satisfiability in finite dimensions

The satisfiability and optimization of finite-dimensional Boolean formulas are studied using percolation theory, rare region arguments, and boundary effects. In contrast with mean-field results, there is no satisfiability transition, though there is a logical connectivity transition. In part of the disconnected phase, rare regions lead to a divergent running time for optimization algorithms. The thermodynamic ground state for the NP-hard two-dimensional maximum-satisfiability problem is typically unique. These results have implications for the computational study of disordered materials.Comment: 4 pages, 4 fig

First excitations in two- and three-dimensional random-field Ising systems

We present results on the first excited states for the random-field Ising model. These are based on an exact algorithm, with which we study the excitation energies and the excitation sizes for two- and three-dimensional random-field Ising systems with a Gaussian distribution of the random fields. Our algorithm is based on an approach of Frontera and Vives which, in some cases, does not yield the true first excited states. Using the corrected algorithm, we find that the order-disorder phase transition for three dimensions is visible via crossings of the excitations-energy curves for different system sizes, while in two-dimensions these crossings converge to zero disorder. Furthermore, we obtain in three dimensions a fractal dimension of the excitations cluster of d_s=2.42(2). We also provide analytical droplet arguments to understand the behavior of the excitation energies for small and large disorder as well as close to the critical point.Comment: 17 pages, 12 figure

Avalanches and the Renormalization Group for Pinned Charge-Density Waves

The critical behavior of charge-density waves (CDWs) in the pinned phase is studied for applied fields increasing toward the threshold field, using recently developed renormalization group techniques and simulations of automaton models. Despite the existence of many metastable states in the pinned state of the CDW, the renormalization group treatment can be used successfully to find the divergences in the polarization and the correlation length, and, to first order in an $\epsilon = 4-d$ expansion, the diverging time scale. The automaton models studied are a charge-density wave model and a ``sandpile'' model with periodic boundary conditions; these models are found to have the same critical behavior, associated with diverging avalanche sizes. The numerical results for the polarization and the diverging length and time scales in dimensions $d=2,3$ are in agreement with the analytical treatment. These results clarify the connections between the behaviour above and below threshold: the characteristic correlation lengths on both sides of the transition diverge with different exponents. The scaling of the distribution of avalanches on the approach to threshold is found to be different for automaton and continuous-variable models.Comment: 29 pages, 11 postscript figures included, REVTEX v3.0 (dvi and PS files also available by anonymous ftp from external.nj.nec.com in directory /pub/alan/cdwfigs

On AIMD Congestion Control in Multiple Bottleneck Networks.

We consider a linear algebraic model of the Additive-Increase Multiplicative-Decrease congestion control algorithm and present results on average fairness and convergence for multiple bottleneck networks. Results are presented for networks of both long-lived and short-lived flows