Drainmod: A Simulation Model for Shallow Water Table Soils

2008 S.C. Water Resources Conference - Addressing Water Challenges Facing the State and Regio

Predicted and Measured Drainable Porosities for Field Soils

Experiments were conducted on large field cores to determine the relationship between drainage volume and water table depth for five soils. The measured drainage volumes were less than predicted from the soil water characteristics for three soils, but were in good agreement for the other two. Drainable porosities were calculated from both theoretical and experimental drainage volume-water table depth relationships by assuming that the unsaturated zone is essentially \u27drained to equilibrium, with the water table. The experimental drainable porosities thus obtained were less than predicted. Drainable porosities for drainage in two-dimensions were calculated from experimental results for one-dimension by assuming an elliptical water table profile. These results gave nearly constant drainable porosities for the layered soils and a variable drain-able porosity for Wagram, a homogeneous, sandy soil

COMPARISON OF DRAINMOD BASED WATERSHED SCALE MODELS

Watershed scale hydrology and water quality models (DRAINMOD-DUFLOW, DRAINMOD-W, DRAINMOD-GIS and WATGIS) that describe the nitrogen loadings at the outlet of poorly drained watersheds were examined with respect to their accuracy and uncertainty in model predictions. Latin Hypercube Sampling (LHS) was applied to determine the impact of uncertainty in estimating field exports and decay coefficients on the uncertainty of the simulated nitrogen loads at the outlet of a 2950 ha coastal plain watershed in eastern North Carolina. Mean daily flow predictions were all within 1 % of the observed flows. Except for the WATGIS model, mean daily nitrate-nitrogen load predictions were within 2 % of the observed load. Statistical test indicated no difference between the predictions of the different models. Uncertainty analysis indicated that uncertainty in quantifying the field exports has greater impact on the uncertainty of outlet loads than does the uncertainty associated with decay coefficient. The uncertainty of predicted outputs from the DRAINMOD-GIS and WATGIS models are similar

Leaf area index (LAI) of loblolly pine and emergent vegetation following a harvest. Trans

ABSTRACT. Forests provide goods and services to society and, often, refugia for plants and animals; forest managers utilize silviculture to provide ecosystem services and to create habitat. On the Coastal Plain of North Carolina, forest management objectives typically include wood fiber production but may also include the maintenance of environmental quality and, sometimes, species diversity. Silvicultural prescriptions alter stand structure and development trajectories by influencing the competitive interactions among plant species for site resources. Early site intervention may include nutrient additions and/or vegetation control; in coastal loblolly pine (Pinus taeda L.) stands, herbaceous and arborescent species can dominate the site leaf area index (LAI) for many years after a harvest (followed by planting). LAI is an important structural and functional component of a forest stand. Many eco‐hydrologic and water quality models do not accurately account for LAI as the process driver to evapotranspiration (ET), and thus they ignore the ecophysiological effects of LAI on site water balance and nutrient loading. We measured LAI of emergent vegetation following a harvest, mechanical site preparation, and then pine planting for a drained loblolly pine plantation in coastal North Carolina. For six years monthly, growing season estimates of LAI were obtained using a LI‐COR LAI 2000 Plant Canopy Analyzer (PCA) for control (D1), thinned (D3), and harvested (D2) watersheds. In this article, we present results from the D2 treatment. In D2, we “harvested ” all emergent vegetation in 18 randomly placed 1 m 2 clip plots for three growing seasons where we estimated LAI using species‐pooled estimates of specific leaf area and total leaf dry mass (i.e., LAICLIP); PCA measurements were recorded prior to clipping (LAIPCA). We als

1924-25: Abilene Christian College Bible Lectures - Full Text

PREFACE The lectures in this volume were delivered in the auditorium of Abilene Christian College during the last week of February in 1924 and 1925. Not all of the lectures delivered during these two weeks are given here, some of those delivering lectures not having responded with their manuscripts. These are given to the public in the belief that the splendid sermons delivered here ought to be read by thousands of Christians who did not have the opportunity of hearing them. Many of those who heard them will desire to read them. May this contribution to the literature of Christian teaching from the minds of some of our best and most faithful laborers in the Master’s vineyard be a continued blessing to all whose lives they touch. BATSELL BAXTER. __________________ PUBLISHER’S ANNOUNCEMENT This volume of Abilene Christian College Lectures is the fourth and comprises the lectures for February 1924 and 1925. The lectures for 1919 were published in one volume, 1920 and 1921 were combined in one volume, as were also the lectures for 1922 and 1923. By putting the lectures for two years in one volume, the reader is saved the expense of an additional book in order to receive the full benefit of these lectures. That these discourses are of great value is recognized by thousands who have heard them orally or have read them on the printed page. Such carefully prepared addresses really and truly merit a permanent place in the literature of the brotherhood of the churches of Christ. They are filled with expositions and analyses of much benefit to younger brethren who are entering upon lines of public service for the church, and they contain instruction on the word of God that is of much value to those out of the church as well as those in the church. The four books comprising the Abilene Christian College Lectures will make a most valuable addition to all libraries. We are at this time, January, 1926, in position to furnish complete sets or any volume to complete any broken set that any of our readers may have. When our present supply is gone, the books will probably not be reprinted as no plates have been made, and the books will be scarce. The messages of hope and love contained in this volume will find their place into the homes of many thousands, and it is to be ardently hoped that they will be read attentively and that they may contribute much to the extension of the power and kingdom of our Lord and Savior Jesus Christ. G. II. P. SHOWALTER. Austin, Texas, January 1, 1926

Hippocampus Leads Ventral Striatum in Replay of Place-Reward Information

While the brain is asleep, the hippocampus plays first fiddle in the orchestra of memory; spatial information is reactivated in the hippocampus shortly in advance of emotional memory traces in the vental striatum

The spike-timing-dependent learning rule to encode spatiotemporal patterns in a network of spiking neurons

We study associative memory neural networks based on the Hodgkin-Huxley type of spiking neurons. We introduce the spike-timing-dependent learning rule, in which the time window with the negative part as well as the positive part is used to describe the biologically plausible synaptic plasticity. The learning rule is applied to encode a number of periodical spatiotemporal patterns, which are successfully reproduced in the periodical firing pattern of spiking neurons in the process of memory retrieval. The global inhibition is incorporated into the model so as to induce the gamma oscillation. The occurrence of gamma oscillation turns out to give appropriate spike timings for memory retrieval of discrete type of spatiotemporal pattern. The theoretical analysis to elucidate the stationary properties of perfect retrieval state is conducted in the limit of an infinite number of neurons and shows the good agreement with the result of numerical simulations. The result of this analysis indicates that the presence of the negative and positive parts in the form of the time window contributes to reduce the size of crosstalk term, implying that the time window with the negative and positive parts is suitable to encode a number of spatiotemporal patterns. We draw some phase diagrams, in which we find various types of phase transitions with change of the intensity of global inhibition.Comment: Accepted for publication in Physical Review