Research on the Morphology of Precipitation and Runoff in Texas

This project has consisted of two distinct phases: (1) equipment modification and installation with associated collection and (2) analyses of data plus development of hydrologic techniques. Errors inherent in the utilization of radar as a hydrologic sensor are discussed. It is shown that errors in the measurement of in-cloud liquid water content can be as much as 100 per cent. Similar results will be obtained in the measurement of rainfall rates by weather radar. It is demonstrated that radar can be used quite effectively in the synthesis of hydrographs. In particular, the feasibility of using radar in streamflow forecasting has been tested for the Little Washita River in Oklahoma. The results were very encouraging. Techniques for hydrograph synthesis are discussed. These have been combined with a stochastic model (which incorporates a sixth-order Markov chain) for rainfall-runoff simulation. The proposed model has been tested thoroughly and appears to hold promise as a forecasting tool. A study was made of Hurricane Beulah which produced extremely heavy precipitation in south Texas and fostered an unprecedented number of tornadoes. The injection of dry air into the area northeast of the parent cyclone was apparently responsible for the extreme instability and development of a large number of tornadoes in that region

Forest-Pest Interaction Dynamics: The Simplest Mathematical Models

This paper is devoted to the investigation of the simplest mathematical models of non-even-aged forests affected by insect pests. Two extremely simple situations are considered: (1) the pest feeds only on young trees; (2) the pest feeds only on old trees. The parameter values of the second model are estimated for the case of balsam fir forests and the eastern spruce budworm. It is shown that an invasion of a small number of pests into a steady-state forest ecosystem could result in intensive oscillations of its age structure. Possible implications of environmental changes on forest ecosystems are also considered

First-principles calculations of 2x2 reconstructions of GaN(0001) surfaces involving N, Al, Ga, In, and as atoms

The ab initio studies presented here employed a pseudopotential-plane-wave method in order to obtain the minimum-energy configurations of various 22 GaN0001 surfaces involving N, Al, Ga, In, and As atoms. Comparison of the various possible reconstructions allows predictions to be made regarding the most energetically favorable configurations. Such comparisons depend on the value of the effective chemical potential of each atomic species, which can be related directly to experimental growth conditions. The most stable structure as a function of chemical potentials is determined. Based on these results we have characterized the effect of N in the adlayer surface and the stability dependence with number of substitutions as a function of the model employed and the possible surfactant character of some of the added atoms. Surface phase diagrams as a function of the chemical potential have been calculated to show the phase transition between the different reconstructions

A Denotational Semantics for First-Order Logic

In Apt and Bezem [AB99] (see cs.LO/9811017) we provided a computational interpretation of first-order formulas over arbitrary interpretations. Here we complement this work by introducing a denotational semantics for first-order logic. Additionally, by allowing an assignment of a non-ground term to a variable we introduce in this framework logical variables. The semantics combines a number of well-known ideas from the areas of semantics of imperative programming languages and logic programming. In the resulting computational view conjunction corresponds to sequential composition, disjunction to ``don't know'' nondeterminism, existential quantification to declaration of a local variable, and negation to the ``negation as finite failure'' rule. The soundness result shows correctness of the semantics with respect to the notion of truth. The proof resembles in some aspects the proof of the soundness of the SLDNF-resolution.Comment: 17 pages. Invited talk at the Computational Logic Conference (CL 2000). To appear in Springer-Verlag Lecture Notes in Computer Scienc

$p+^{4,6,8}He elastic scattering at intermediate energies

Using a relativistic nuclear optical potential consisting of a Lorentz scalar, $V_{s}$, and the time-like component of a four-vector potential, $V_{0}$, we calculate elastic scattering differential cross sections and polarizations for $p+^{4}$He at intermediate energies for which experimental data are available. We also calculate the differential cross sections and analyzing powers for $p+^{6,8}$He at intermediate energies and compare with the few available experimental data.Comment: 09 pages, 04 figure

Development and Interim Evaluation of WeCare Indiana: a Community-tailored Text Messaging Intervention to Reduce Infant Mortality in East Central Indiana

poster abstractBackground: Text messaging is an effective way to distribute health information and reduce risky health behaviors.1,2 In 2014, the East Central Indiana Fetal and Infant Mortality Program of the Delaware County Health Department developed a community-based text messaging intervention program called “WeCare Indiana” as an innovative approach to promote positive pregnancy outcomes. This abstract reports the interim evaluation of health promotional text messages for prenatal clients. Methods: The program was developed using a community-collaborative model. Over 200 prenatal and infant health text messages were reviewed and evaluated by community representatives. Messages included information regarding fetal and infant development, health promotion, and risk prevention strategies with links to local resources. Prenatal messages were then reviewed by prenatal clients for their relevance, clarity, and likelihood to change healthrelated behavior during pregnancy. The program was promoted locally and currently has 98 enrollees. A 4-month interim program evaluation was developed to assess program awareness, reasons for enrolling or not enrolling, and overall satisfaction with text message content. A convenience sample of prenatal clients at a Federally Qualified Health Center participated in the evaluation process. Results: Of the 43 prenatal clients that participated, 10 (23%) clients had heard about the health messaging service. Of those participants, 6 (60%) had chosen to enroll in the program. Enrollees reported hearing about the program through word of mouth, posters, fliers, health care providers, and social media. Reasons given for not enrolling included lack of awareness or interest, technical difficulties, and procrastination. All enrollees reported that the messages were helpful. Conclusions: An effort to reduce fetal and infant mortality in East Central Indiana led to the development and evaluation of community-tailored health messages. The evaluation results will be used to encourage client awareness and enrollment in the program

Does Media Affect Learning: Where Are We Now?

It is time to extinguish the argument as to whether or not the media of 1983 could, should or would affect learning outcomes. The technological advances that have occurred in the 20 years since Clark sparked the debate and Kozma fanned the flames have made the question irrelevant. High-speed, portable, reasonably priced computers, the Internet, and the World Wide Web have changed the face of how, when, and where learning occurs. The media of 2004 does affect learning. The question is no longer if; the question is how

Nodes of the Gap Function and Anomalies in Thermodynamic Properties of Superfluid 3^3He

Departures of thermodynamic properties of three-dimensional superfluid $^3$He from the predictions of BCS theory are analyzed. Attention is focused on deviations of the ratios $\Delta(T=0)/T_c$ and $[C_s(T_c)-C_n(T_c)]/C_n(T_c)$ from their BCS values, where $\Delta(T=0)$ is the pairing gap at zero temperature, $T_c$ is the critical temperature, and $C_s$ and $C_n$ are the superfluid and normal specific heats. We attribute these deviations to the momentum dependence of the gap function $\Delta(p)$, which becomes well pronounced when this function has a pair of nodes lying on either side of the Fermi surface. We demonstrate that such a situation arises if the P-wave pairing interaction $V(p_1,p_2)$, evaluated at the Fermi surface, has a sign opposite to that anticipated in BCS theory. Taking account of the momentum structure of the gap function, we derive a closed relation between the two ratios that contains no adjustable parameters and agrees with the experimental data. Some important features of the effective pairing interaction are inferred from the analysis.Comment: 17 pages, 4 figure