Design criteria for bottom-withdrawal (lake-cleaning) spillway

"A pond or lake equipped with a bottom-withdrawal spillway will store the highest quality water possible for a reservoir in a given location. This is desirable when the reservoir will provide water for municipalities, livestock, households, fish production, recreation, field or orchard spraying, trickle irrigation, or other uses requiring high quality water."--First page.David Rausch (USDA-ARS, Watershed Research Unit), Don Pfost (Department of Agricultural Engineering, College of Agriculture), and Larry W. Caldwell (USDA, Soil Conservation Service, Columbia, Missouri)New 4/85/10

Operating and maintaining grassed outlet terrace systems

"The proper operation of terrace systems depends on good farming practices and prompt correction of problems. Terraces should be inspected at least anually. Terrace ridge height and shape should be maintained as built. Occasionally, a modification may be required (for example, if you change basic machinery size from 6-row to 8-row)."--First page.Don Pfost (Department of Agricultural Engineering, College of Agriculture), Larry Caldwell (USDA, SOil Conservation Service, Columbia, Missouri)New 9/84/10

Constraints on Cosmic Strings due to Black Holes Formed from Collapsed Cosmic String Loops

The cosmological features of primordial black holes formed from collapsed cosmic string loops are studied. Observational restrictions on a population of primordial black holes are used to restrict $f$, the fraction of cosmic string loops which collapse to form black holes, and $\mu$, the cosmic string mass-per-unit-length. Using a realistic model of cosmic strings, we find the strongest restriction on the parameters $f$ and $\mu$ is due to the energy density in $100 MeV$ photons radiated by the black holes. We also find that inert black hole remnants cannot serve as the dark matter. If earlier, crude estimates of $f$ are reliable, our results severely restrict $\mu$, and therefore limit the viability of the cosmic string large-scale structure scenario.Comment: (Plain Tex, uses tables.tex -- wrapped lines corrected), 11 pages, FERMILAB-Pub-93/137-

Feasibility Study for Development of Statewide Evapotranspiration Network

Information was collected on existing mesonets, potential evapotranspiration networks, and stakeholder needs, in support of a comprehensive feasibility study for a Texas statewide evapotranspiration network. This report summarizes the data and information collected from interviews and online resources regarding the purpose, design, operation, and value of these mesonets. It analyzes existing network data within Texas and evaluates the costs and benefits associated with operating a more comprehensive or integrated network. Finally, it presents options for a sustainable Texas mesonet based on successes elsewhere and the specific needs and resources of Texas. A mesonet here refers to a set of weather stations designed to detect and monitor weather phenomena ranging in size from several miles to hundreds of miles (the "mesoscale"). Such disturbances include flooding and thunderstorms (i.e. convective precipitation), high winds, droughts, and heatwaves. Instruments may be located as high as 10 m above the ground, and stations are generally located to avoid influences from urban landscapes, irrigation, forests, and large bodies of water. This report restricts the term mesonet to networks that serve a variety of needs or stakeholders. ET (Evapotranspiration) networks differ in both their objectives and measurements. Their objective is to determine the atmospheric demand for water evaporation and transpiration from land covered by a well-watered reference crop – either alfalfa or clipped grass. Such data is valuable for irrigation scheduling for agricultural production and for improving efficiencies in landscape watering for homes and businesses. ET networks use specific instruments often at 2 m heights sited well within a homogenous field of a well-maintained reference crop. Requirements of growers and stakeholders often drive the siting and spacing. An ET network has a particular specialized use while a mesonet is more of a multi-purpose network. Many existing mesonets in other states were originally established for agricultural purposes, while others were established in support of public safety. Most have been in operation for an average of twenty years and by now serve a broad range of sectors and constituencies. In Texas, there are three mesonets that serve a variety of purposes: the West Texas Mesonet, the Lower Colorado River Authority (LCRA) Hydromet Network, and the TexMesonet. There is one dedicated ET network, the TexasET Network, and there are numerous other single-purpose networks. All surveyed mesonets and ET networks measure air temperature, relative humidity, wind, and precipitation. Solar radiation is measured at all stations in the TexasET and TexMesonet networks, but only partially in the other two networks. In addition, many also measure soil temperature and soil moisture at a variety of subsurface levels as well as wind or temperature at multiple above-ground levels. Data transmission from individual stations is predominantly by cellular network. Users access the data via web sites, text alerts, apps, and through retransmission of data to larger aggregation networks such as the Meteorological Assimilation Data Ingest System, the National Mesonet Program, and MesoWest. Most mesonets quality control their data to either World Meteorological Organization or National Weather Service standards. Individual startup costs range from $6,200 to$25,000 per station, and network maintenance and operating costs range from $1,600 to$6,000 per station. Differences in cost largely reflect differences in instrumentation and maintenance needs. Maintenance costs for ET stations can be high due to irrigation infrastructure and land management required to maintain the reference grasses. Staffing needs depend on the mix of employees and outside contractors; labor-intensive tasks include station, instrumentation, and communication maintenance, calibration, product development, and administration. The benefits gained from fully functional ET networks are substantial. Analyses of benefits of existing ET networks find typical water savings of several inches per year on irrigated cropland, implying potential water savings exceeding one million acre-feet per year within the agriculture sector alone. Overall, the potential economic return on investment is substantial, with one study estimating it at 20:1. Mesonet business models range from comprehensive centralized networks with fully integrated operations to secondhand aggregators of data from existing networks. Most of the successful networks examined in this report operate on a partnership model with some centralized tasks and funding and some tasks and funding shouldered at the local level. Nearly all mesonets function through university or multi-university partnerships. In most cases, data is free of charge. In Texas, an appropriate model would be a consortium model, consisting of the Texas Water Development Board, universities such as Texas Tech University, Texas A&M University, and the University of Texas, and other statewide or regional stakeholders/operators such as the the Texas A&M Agrilife Extension Service, Lower Colorado River Authority and the Electricity Reliability Council of Texas. Additional stakeholder participation can be formalized through an advisory board. Successful mesonets elsewhere have avoided challenges which can potentially lead to failure of the network, including: 1. lacking an overall network vision; 2. failing to properly engage potential stakeholders; 3. misdiagnosing local needs; 4. lacking diversification in revenue streams; 5. not fully exploring potential government partners; 6. not properly budgeting for maintenance costs; understaffing; 7. lacking data and metadata standards; 8. insufficient communications infrastructure; and 9. not providing reliable web/automated dissemination of data.Texas Water Development Boar

An Examination of Recent Transformations to the BV(RI)_C Photometric System from the Perspective of Stellar Models for Old Stars

Isochrones for ages > 4 Gyr and metallicities in the range -2.5 < [Fe/H] < +0.3 that take the diffusion of helium and recent advances in stellar physics into account are compared with observations in the Johnson-Cousins BV(RI)_C photometric system for several open and globular star clusters. The adopted color-Teff relations include those which we have derived from the latest MARCS model atmospheres and empirical transformations for dwarf and subgiant stars given by Casagrande et al (2010, A&A, 512, 54; CRMBA). Those reported by VandenBerg & Clem (2003, AJ, 126, 778) have also been considered, mainly to resolve some outstanding questions concerning them. Remarkably, when the subdwarfs in the CRMBA data set that have sigma_pi/pi < 0.15 are superimposed on a set of 12 Gyr isochrones spanning a wide range in [Fe/H], the inferred metallicities and effective temperatures agree, in the mean, with those given by CRMBA to within +/- 0.05 dex and +/- 10 K, respectively. Thus the hot Teff scale derived by CRMBA is nearly identical with that predicted by stellar models and consequently, there is excellent consistency between theory and observations on the H-R diagram and the different color-magnitude diagrams considered in this investigation. To obtain similar consistency, the colors obtained from the MARCS and VandenBerg & Clem B-V vs. Teff relations for metal-poor dwarf stars should be adjusted to the red by 0.02-0.03 mag. In general, isochrones that employ the CRMBA transformations provide reasonably good fits to our BV(RI)_C photometry for main-sequence stars in the globular clusters 47 Tuc, M3, M5, M92 and NGC 1851 - but not the cluster giants (when adopting the synthetic MARCS colors). We speculate that differences between the actual heavy-element mixtures and those assumed in the theoretical models may be the primary cause of this difficulty.Comment: To appear in 2010, AJ, 140, 102

Lack of adverse health effects following 30-weeks of dietary exposure to acrylamide at low doses in male F344 rats

AbstractUnderstanding the health hazards following exposure to food-borne acrylamide, especially at low levels typified by human diets, is an ongoing food safety issue. We recently published results from a study that aimed to understand the effects of acrylamide short-term exposure at doses known to cause tumors in rodents, demonstrating that a number of key toxicological end points were altered by acrylamide exposure. Additionally, we reported that at much lower doses for 30 weeks of exposure, dietary acrylamide was ‘not a complete carcinogen’ to the colon in an organ-specific rodent carcinogenesis study but acted as a co-carcinogen along with azoxymethane (AOM, a colon-specific carcinogen). Here, we present toxicological data from a sub-set of this long-term exposure study from animals that received saline (instead of AOM). Briefly, male F344 rats were randomized to receive acrylamide at 0.5, 1.0 and 2.0mg/kg diet (∼0.02, 0.04, and 0.09mg/kg BW/day, respectively) or no acrylamide (control), for 30 weeks; all rats were then euthanized and their tissues harvested and processed for toxicological evaluation. We report that at the doses tested, acrylamide did not cause any changes in general well-being, body weight or food intake. Similarly, acrylamide did not cause any biologically relevant change in parameters associated with immunophenotyping, serum biochemistry or hematology. Histopathology assessment of tissues showed no changes except in the testis, where non-specific mild lesions were observed in all the groups, inclusive of the controls. No neuropathological effects of acrylamide were observed in the brain and nerve tissues. Together, these results suggest that acrylamide administered to rats through the diet at low doses for 30 weeks did not cause any toxicologically relevant changes. Given that the doses of acrylamide in the current study are low and are comparable to human dietary exposure, this null-effect study provides data that contribute to the body of scientific evidence relevant to understanding the health effects of acrylamide