Final Report: 1975 Appalachian Community Based Right to Read Programs

1975 Final Report on the Appalachian Community Based Right to Read Programs compiled by Sharon Moore and Charles J. Bailey in August of 1975

State-insensitive bichromatic optical trapping

We propose a scheme for state-insensitive trapping of neutral atoms by using light with two independent wavelengths. In particular, we describe the use of trapping and control lasers to minimize the variance of the potential experienced by a trapped Rb atom in ground and excited states. We present calculated values of wavelength pairs for which the 5s and 5p_{3/2} levels have the same ac Stark shifts in the presence of two laser fields.Comment: 5 pages, 4 figure

Alfalfa Yields from Mixtures of Dormant and Non-dormant Varieties

During the establishment year, alfalfa seedings typically yield only 40-60% of fully established stands. All alfalfa varieties grown in Iowa are classified as dormant or moderately dormant, a characteristic that is important for winter survival. However, as plants become dormant in late summer, their yield declines. Alfalfa varieties from the southwestern United States are non-dormant and continue to grow until the autumn freeze, but tend to die over winter. The objective of this experiment was to determine if including a proportion of non-dormant seed at planting could improve establishment year yield without affecting successive year yields or forage quality. The rationale for this experiment is that more plants are present in the first year of a stand than in successive years when individual plants grow larger as their crowns expand. Because of normal plant loss, we reasoned that death of non-dormant plants after the first winter might not adversely affect the yields of the remaining stand

Eastern gamagrass seed dormancy

Eastern gamagrass has considerable value as a forage source and conservation aid, but can be very difficult to establish because its seed does not germinate easily, even with all the necessary environmental factors present. Understanding seed dormancy in eastern gamagrass is the major objective of this work

Potential net primary productivity in South America: application of a global model

We use a mechanistically based ecosystem simulation model to describe and analyze the spatial and temporal patterns of terrestrial net primary productivity (NPP) in South America. The Terrestrial Ecosystem Model (TEM) is designed to predict major carbon and nitrogen fluxes and pool sizes in terrestrial ecosystems at continental to global scales. Information from intensively studies field sites is used in combination with continental—scale information on climate, soils, and vegetation to estimate NPP in each of 5888 non—wetland, 0.5° latitude °0.5° longitude grid cells in South America, at monthly time steps. Preliminary analyses are presented for the scenario of natural vegetation throughout the continent, as a prelude to evaluating human impacts on terrestrial NPP. The potential annual NPP of South America is estimated to be 12.5 Pg/yr of carbon (26.3 Pg/yr of organic matter) in a non—wetland area of 17.0 ° 106 km2. More than 50% of this production occurs in the tropical and subtropical evergreen forest region. Six independent model runs, each based on an independently derived set of model parameters, generated mean annual NPP estimates for the tropical evergreen forest region ranging from 900 to 1510 g°m—2°yr—1 of carbon, with an overall mean of 1170 g°m—2°yr—1. Coefficients of variation in estimated annual NPP averaged 20% for any specific location in the evergreen forests, which is probably within the confidence limits of extant NPP measurements. Predicted rates of mean annual NPP in other types of vegetation ranged from 95 g°m—2°yr—1 in arid shrublands to 930 g°m@?yr—1 in savannas, and were within the ranges measured in empirical studies. The spatial distribution of predicted NPP was directly compared with estimates made using the Miami mode of Lieth (1975). Overall, TEM predictions were °10% lower than those of the Miami model, but the two models agreed closely on the spatial patterns of NPP in south America. Unlike previous models, however, TEM estimates NPP monthly, allowing for the evaluation of seasonal phenomena. This is an important step toward integration of ecosystem models with remotely sensed information, global climate models, and atmospheric transport models, all of which are evaluated at comparable spatial and temporal scales. Seasonal patterns of NPP in South America are correlated with moisture availability in most vegetation types, but are strongly influenced by seasonal differences in cloudiness in the tropical evergreen forests. On an annual basis, moisture availability was the factor that was correlated most strongly with annual NPP in South America, but differences were again observed among vegetation types. These results allow for the investigation and analysis of climatic controls over NPP at continental scales, within and among vegetation types, and within years. Further model validation is needed. Nevertheless, the ability to investigate NPP—environment interactions with a high spatial and temporal resolution at continental scales should prove useful if not essential for rigorous analysis of the potential effects of global climate changes on terrestrial ecosystems

Interactions between carbon and nitrogen dynamics in estimating net primary productivity for potential vegetation in North America

We use the terrestrial ecosystem model (TEM), a process-based model, to investigate how interactions between carbon (C) and nitrogen (N) dynamics affect predictions of net primary productivity (NPP) for potential vegetation in North America. Data on pool sizes and fluxes of C and N from intensively studied field sites are used to calibrate the model for each of 17 non-wetland vegetation types. We use information on climate, soils, and vegetation to make estimates for each of 11,299 non-wetland, 0.5° latitude × 0.5° longitude, grid cells in North America. The potential annual NPP and net N mineralization (NETNMIN) of North America are estimated to be 7.032 × 1015 g C yr−1 and 104.6 × 1012 g N yr−1, respectively. Both NPP and NETNMIN increase along gradients of increasing temperature and moisture in northern and temperate regions of the continent, respectively. Nitrogen limitation of productivity is weak in tropical forests, increasingly stronger in temperate and boreal forests, and very strong in tundra ecosystems. The degree to which productivity is limited by the availability of N also varies within ecosystems. Thus spatial resolution in estimating exchanges of C between the atmosphere and the terrestrial biosphere is improved by modeling the linkage between C and N dynamics. We also perform a factorial experiment with TEM on temperate mixed forest in North America to evaluate the importance of considering interactions between C and N dynamics in the response of NPP to an elevated temperature of 2°C. With the C cycle uncoupled from the N cycle, NPP decreases primarily because of higher plant respiration. However, with the C and N cycles coupled, NPP increases because productivity that is due to increased N availability more than offsets the higher costs of plant respiration. Thus, to investigate how global change will affect biosphere-atmosphere interactions, process-based models need to consider linkages between the C and N cycles

Radiative and Collisional Jet Energy Loss in the Quark-Gluon Plasma at RHIC

We calculate and compare bremsstrahlung and collisional energy loss of hard partons traversing a quark-gluon plasma. Our treatment of both processes is complete at leading order in the coupling and accounts for the probabilistic nature of the jet energy loss. We find that the nuclear modification factor $R_{AA}$ for neutral $\pi^0$ production in heavy ion collisions is sensitive to the inclusion of collisional and radiative energy loss contributions while the averaged energy loss only slightly increases if collisional energy loss is included for parent parton energies $E\gg T$. These results are important for the understanding of jet quenching in Au+Au collisions at $200 {\rm AGeV}$ at RHIC. Comparison with data is performed applying the energy loss calculation to a relativistic ideal (3+1)-dimensional hydrodynamic description of the thermalized medium formed at RHIC.Comment: 4 pages, 3 figure

BALL SIZE AND WEIGHT EFFECTS ON THROWING KINEMATICS AND KINETICS IN YOUTH BASEBALL ATHLETES

In baseball, youth players play on smaller fields with shorter base path distance, pitching distance, and smaller mounds. Despite this, the baseball itself remains unchanged for youth athletes. This prospective cohort analyzed the kinematics and kinetics of 38 youth baseball pitchers while using modified sized and weighted baseballs. An ANOVA was used to determine statistical significance amongst ball modifications. ANOVA results show significance between the 3oz-5oz baseball with the 3oz baseball decreasing elbow varus torque. This is a preliminary study on the effects of modified baseballs on youth athletes

Distribution of Legumes along Gradients of Slope and Soil Electrical Conductivity in Pastures

Legumes establish and persist on backslope landscape positions but fail on summits and toeslopes in southeastern Iowa pastures, suggesting that these pastures be managed site specifically. Visual delineation of landscape positions, however, can be difficult, and char- acterization of spatial variability through soil sampling is expensive. Creation of digital elevation models (DEM) and apparent soil electrical conductivity (ECa) mapping are inexpensive alternatives to de- scribing field conditions. Our objective was to examine the relationships of DEM-derived slope, soil ECa, and legume distribution in pastures.We examined these relationships across four 1.4-ha pastures. Each pasture was divided into 0.46-ha plots that were assigned one of three stocking treatments: continuous, rotational, and nongrazed. We found that legumes, as a percentage of pasture cover,were greatest at 15 to 20% slopes and intermediate values of soil ECa. The absolute ECa value at which legumes were maximized varied by plot within each stocking system and year ECa was measured. When ECa was standardized by pasture and year, however, a nonlinear response curve explained 23 to 42% of the variation of legume cover across the plots. Grazing reduced competition from smooth brome (Bromus inermis Leyss.) and reed canarygrass (Phalaris arundinacea L). These grasses dominated at 0 to 8% slopes and where ECa was either low or high in value. We concluded that slope and soil ECa data are useful in identifying sites where legumes are successful in pastures and showed potential for use in site-specific management of pastures