Determination of Semivariogram Models to Krige Hourly and Daily Solar Irradiance in Western Nebraska*

In this paper, linear and spherical semivariogram models were determined for use in kriging hourly and daily solar irradiation for every season of the year. The data used to generate the models were from 18 weather stations in western Nebraska. The models generated were tested using cross validation. The performance of the spherical and linear semivariogram models were compared with each other and also with the semivariogram models based on the best fit to the sample semivariogram of a particular day or hour. There were no significant differences in the performance of the three models. This result and the comparable errors produced by the models in kriging indicated that the linear and spherical models could be used to perform kriging at any hour and day of the year without deriving an individual semivariogram model for that day or hour. The seasonal mean absolute errors associated with kriging, within the network, when using the spherical or the linear semivariograms models were between 10% and 13% of the mean irradiation for daily irradiation and between 12% and 20% for hourly irradiation. These errors represent an improvement of 1%–2% when compared with replacing data at a given site with the data of the nearest weather station

Operational Improvements From the Automatic Dependant Surveillance Broadcast In-Trail Procedure in the Pacific Organized Track System

The Federal Aviation Administration's Surveillance and Broadcast Services Program has supported implementation of the Automatic Dependant Surveillance Broadcast (ADS-B) In-Trail Procedure (ITP) on commercial revenue flights. ADS-B ITP is intended to be used in non-radar airspace that is employing procedural separation. Through the use of onboard tools, pilots are able to make a new type of altitude change request to an Air Traffic Service Provider (ATSP). The FAA, in partnership with United Airlines, is conducting flight trials of the ITP in revenue service in the Pacific. To support the expansion of flight trials to the rest of the US managed Pacific Airspace Region, a computerized batch study was conducted to investigate the operational impacts and potential benefits that can be gained through the use of the ITP in the Pacific Organized Track System (PACOTS). This study, which simulated the Oakland managed portion of the PACOTS, suggests that potential benefits in the PACOTS are significant with a considerable increase in time spent at optimum altitude and associated fuel savings

Hurricane Intensity, Sea Surface Temperature, and Stochastic Variation

Abstract not provide

Causal Effects of Prenatal Drug Exposure on Birth Defects with Missing by Terathanasia

We investigate the causal effects of drug exposure on birth defects, motivated by a recent cohort study of birth outcomes in pregnancies of women treated with a given medication, that revealed a higher rate of major structural birth defects in infants born to exposed versus unexposed women. An outstanding problem in this study was the missing birth defect outcomes among pregnancy losses resulting from spontaneous abortion. This led to missing not at random because, according to the theory of "terathanasia", a defected fetus is more likely to be spontaneously aborted. In addition, the previous analysis stratified on live birth against spontaneous abortion, which was itself a post-exposure variable and hence did not lead to causal interpretation of the stratified results. In this paper we aimed to estimate and provide inference for the causal parameters of scientific interest, including the principal effects, making use of the missing data mechanism informed by terathanasia. During this process we also dealt with complications in the data including left truncation, observational nature, and rare events. We report our findings which shed light on how studies on causal effects of medication or other exposures during pregnancy may be analyzed

Ecological Genomics of Nematode Community Interactions: Model and Non-model Approaches

The effects of human-induced environmental change are evident at multiple levels of biological organization. To date, most environmental change studies have focused on effects at the ecosystem, community, and organismal levels. However, the ultimate controls of biological responses are located in the genome. Thus, genetic and genomic studies of organismal responses to environmental changes are necessary. Recent advances in genome analysis now make such analyses possible. In this chapter we describe a research approach and program that can begin to span this gap by using genome-enabled approaches to characterize organismal changes and then employing a genetically tractable model organism to identify genes involved in the response to environmental perturbations

Loss Sharing Rules for Bank Holding Companies: An Assessment of the Federal Reserve's Source-of-Strength Policy and the FDIC's Cross Guarantee Authority

In this article, we critically examine two policies designed to protect the deposit insurance funds—the Federal Reserve Board’s source-of-strength policy and the FDIC’s cross-guarantee authority. We discuss why each of the policies was adopted and how effective each has been in practice since its implementation. We then evaluate the future application and usefulness of the two policies in light of the structural changes that have resulted from industry consolidation and the financial modernization of the 1990s

Surface and Subsurface Attenuation of Trenbolone Acetate Metabolites and Manure-Derived Constituents in Irrigation Runoff on Agro-Ecosystems

Although studies have evaluated the ecotoxicity and fate of trenbolone acetate (TBA) metabolites, namely 17α-trenbolone (17α-TBOH), 17β-trenbolone (17β-TBOH), and trendione (TBO), their environmental transport processes remain poorly characterized with little information available to guide agricultural runoff management. Therefore, we evaluated TBA metabolite transport in representative agricultural systems with concurrent assessment of other manure-derived constituents. Leachate generated using manure from TBA-implanted cattle was applied to a subsurface infiltration plot (4 m) and surface vegetative filter strips (VFSs; 3, 4, and 5 m). In the subsurface experiment, 17α-TBOH leachate concentrations were 36 ng L−1 but decreased to 12 ng L−1 in initial subsurface discharge. Over 75 minutes, concentrations linearly increased to 23 ng L−1 (C/Co = 0.32–0.64). In surface experiments (n = 4), 17α-TBOH leachate concentrations ranged from 11–150 ng L−1, remained nearly constant with time, but were attenuated by ∼70–90% after VFS treatment with no statistical dependence on the VFS length. While attenuation clearly occurred, the observations of a highly mobile fraction of all constituents in both surface runoff and subsurface discharge suggest that these treatment strategies may not always be capable of achieving threshold discharge concentrations. To attain no observed adverse effect levels (NOAELs) in receiving waters, concurrent assessment of leachate concentrations and available dilution capacities can be used to guide target treatment performance levels for runoff management. Dilution is usually necessary to achieve NOAELs, and receiving waters with less than 70–100 fold dilution capacity are at the highest risk for steroidal endocrine disruption

Modern Erosion Rates and Loss of Coastal Features and Sites, Beaufort Sea Coastline, Alaska

This study presents modern erosion rate measurements based upon vertical aerial photography captured in 1955, 1979, and 2002 for a 100 km segment of the Beaufort Sea coastline. Annual erosion rates from 1955 to 2002 averaged 5.6 m a-1. However, mean erosion rates increased from 5.0 m a-1 in 1955–79 to 6.2 m a-1 in 1979–2002. Furthermore, from the first period to the second, erosion rates increased at 60% (598) of the 992 sites analyzed, decreased at 31% (307), and changed less than ± 30 cm at 9% (87). Historical observations and quantitative studies over the past 175 years allowed us to place our erosion rate measurements into a longer-term context. Several of the coastal features along this stretch of coastline received Western place names during the Dease and Simpson expedition in 1837, and the majority of those features had been lost by the early 1900s as a result of coastline erosion, suggesting that erosion has been active over at least the historical record. Incorporation of historical and modern observations also allowed us to detect the loss of both cultural and historical sites and modern infrastructure. U.S. Geological Survey topographic maps reveal a number of known cultural and historical sites, as well as sites with modern infrastructure constructed as recently as the 1950s, that had disappeared by the early 2000s as a result of coastal erosion. We were also able to identify sites that are currently being threatened by an encroaching coastline. Our modern erosion rate measurements can potentially be used to predict when a historical site or modern infrastructure will be affected if such erosion rates persist.Cette étude présente les mesures de taux d’érosion contemporains établies en fonction de photographies aériennes verticales prises en 1955, en 1979 et en 2002 sur un segment de 100 km du littoral de la mer de Beaufort. Entre 1955 et 2002, les taux d’érosion annuels ont atteint 5,6 m a-1 en moyenne. Cependant, les taux d’érosion moyens se sont accrus pour passer de 5,0 m a-1 pendant les années 1955- 1979 à 6,2 m a-1 dans les années 1979 - 2002. Par ailleurs, de la première période à la deuxième période, les taux d’érosion ont augmenté à 60 % (598) des 992 sites analysés, ont diminué dans le cas de 31 % (307) des sites, et changé de moins de ± 30 cm à 9 % (87) des sites. Les observations historiques et les études quantitatives recueillies au cours des 175 dernières années nous ont permis de placer nos mesures des taux d’érosion dans un contexte à plus long terme. Plusieurs des caractéristiques côtières le long de cette étendue du littoral ont reçu des noms d’endroits typiques de l’Ouest dans le cadre de l’expédition de Dease et Simpson en 1837, et la majorité de ces caractéristiques avaient disparu vers le début des années 1900 en raison de l’érosion côtière. Cela laisse donc entendre que l’érosion s’est à tout le moins manifestée pendant la période visée par les données historiques. Grâce à l’utilisation d’observations historiques et d’observations contemporaines, nous avons pu déceler la perte de sites culturels et historiques de même que d’infrastructures modernes. Les cartes topographiques de l’U.S. Geological Survey révèlent un certain nombre de sites culturels et historiques connus, ainsi que des sites dotés d’infrastructures modernes datant des années 1950, sites et infrastructures qui avaient disparu vers le début des années 2000 en raison de l’érosion côtière. Nous avons également été en mesure de cerner des sites qui sont présentement menacés par un littoral qui empiète sur le terrain. Nos mesures des taux d’érosion contemporains pourraient éventuellement servir à déterminer à quel moment un site historique ou une infrastructure moderne sera touché advenant que des taux d’érosion similaires persistent