Timing of riverine export of nitrate and phosphorus from agricultural watersheds in Illinois: implications for reducing nutrient loading to the Mississippi River

Agricultural watersheds in the upper Midwest are the major source of nutrients to the Mississippi River and Gulf of Mexico, but temporal patterns in nutrient export and the role of hydrology in controlling export remain unclear. Here we reporton NO3(-)-N, dissolved reactive phosphorus (DRP), and total P export from three watersheds in Illinois during the past 8-12 years. Our program of intensive, long-term monitoring allowed us to assess how nutrient export was distributed across the range of discharge that occurred at each site and to examine mechanistic differences between NO3(-)-N and DRP export from the watersheds. Last, we used simple simulations to evaluate how nutrient load reductions might affect NO3(-)-N and P export to the Mississippi River from the Illinois watersheds. Artificial drainage through under-field tiles was the primary mechanism for NO3(-)-N export from the watersheds. Tile drainage and overland flow contributed to DRP export, whereas export of particulate P was almost exclusively from overland flow. The analyses revealed that nearly all nutrient export occurred when discharge was > or = median discharge, and extreme discharges (> or = 90th percentile) were responsible for >50% of the NO3(-)-N export and >80% of the P export. Additionally, the export occurred annually during a period beginning in mid-January and continuing through June. These patterns characterized all sites, which spanned a 4-fold range in watershed area. The simulations showed that reducing in-stream nutrient loads by as much as 50% during periods of low discharge would not affect annual nutrient export from the watersheds.     

Mice expressing human but not murine beta3-adrenergic receptors under the control of human gene regulatory elements

Beta-adrenergic receptors (ARs) are expressed predominantly in adipose tissue, and beta3-selective agonists are effective anti-obesity drugs in rodents. Rodent and human beta3-ARs differ with respect to expression in white versus brown adipocytes as well as their ability to be stimulated by beta3-AR-selective agonists. Humans express beta3-AR mRNA abundantly in brown but not white adipocytes, while rodents express beta3-AR mRNA abundantly in both sites. To determine the basis for this difference, we have transgenically introduced 74 kilobases (kb) of human beta3-AR genomic sequence into gene knockout mice lacking beta3-ARs. Importantly, human beta3-AR mRNA was expressed only in brown adipose tissue (BAT) of transgenic mice, with little or no expression being detected in white adipose tissue (WAT), liver, stomach, small intestine, skeletal muscle, and heart. This pattern of expression differed from that observed in mice bearing a murine beta3-AR genomic transgene in which beta3-AR mRNA was expressed in both WAT and BAT, but not in other sites. Furthermore, we have transgenically introduced smaller human constructs containing -14.5 and -0.6 kb of upstream sequence into beta3-AR gene knockout mice. Both -14.5 and -0.6 kb constructs were expressed in BAT but not WAT. Thus, human but not murine cis-regulatory elements direct beta3-AR gene expression preferentially to brown adipocytes. Identification of responsible cis-regulatory element(s) and relevant trans-acting factor(s) should provide insight into mechanisms controlling human beta3-AR gene expression. In addition, the beta3-AR agonist, CGP-12177, stimulated oxygen consumption in mice expressing human but not murine beta3-ARs by 91% compared with only 49% in control beta3-AR gene knockout mice, demonstrating that the human beta3-AR can functionally couple with energy expenditure. These "humanized" mice should assist us in the development of drugs that may become effective anti-obesity agents in humans.     

Extreme Programming and Agile Software Development Methodologies

Several agile (i.e., lightweight) development methodologies, especially extreme programming (XP), have been argued to be a solution to many of the problems that continue to plague software development projects. The authors provide a useful evaluation of such approaches, including a discussion of the values that underlie the XP methodology.     

Interpolation modeling of S-parameter data bases for use in Monte Carlo simulations

A statistical interpolation technique is presented for modeling S-parameter measurements for use in statistical analysis and design of circuits. This is accomplished by interpolating among the measurements in an S-parameter data base in a statistically valid manner.     

Analysis of an ice-condenser containment building anchorage system

A 3-D non-linear finite-element analysis of an ice-condenser steel containment anchorage system, which considers the parameters that affect this complex system, was performed. The model included a portion of the containment shell, knuckle plate, base plate, reinforced concrete mat, anchor bolt, anchorage system, soil foundation material, and a portion of the containment shield building. The results showed the early formation of conical failure surfaces within the concrete that are associated with the brittle failure mode. However, these surfaces were not completely developed to the top of the containment basemat. No high strains were recorded in the anchorage system or the containment shell. Hence, failure of the containment anchorage system was not hypothesized.     

Fraunhofer diffraction to determine the twin angle in single-crystal BaTiO3

We present a new method for determining the electrically induced twin angle alpha of a (100) bulk single crystal of barium titanate (BaTiO3) using a nondestructive optical technique based on Fraunhofer diffraction. The technique required two steps that were performed simultaneously. First, we analyzed the diffracted light intensity captured with a line camera. Second, we measured the size of the diffracting element by analyzing images of crystal's surface taken with a CCD camera. The value obtained for the twin angle is 0.67 degrees +/- 0.05 degrees, which compares favorably with the theoretical value of 0.63 degrees.     

Biosynthetic precursors of fungal pyrrolizidines, the loline alkaloids

Loline alkaloids are saturated pyrrolizidines with a substituted 1-amino group and an oxygen bridge between C2 and C7, and are insecticidal metabolites of plant-symbiotic fungi (endophytes). Cultures of the endophyte, Neotyphodium uncinatum, incorporated labeled L-proline and L-homoserine into the 1-aminopyrrolizidine, N-formylloline. The A-ring carbons C1-C3 and the N1 were derived from L-homoserine; the B-ring carbons C5-C8 and the ring nitrogen were derived from L-proline. Incorporation of both deuterium atoms from L-[4,4-(2H2)]homoserine and feeding tests with labeled L-methionine indicated that L-homoserine incorporation was not achieved via aspartyl semialdehyde or S-adenosylmethionine, but probably involved a highly novel N--C bond-forming gamma-substitution reaction.     

Oxidation of TD nickel at 1050 and 1200°C as compared to three grades of nickel of different purity

The oxidation of three nickels of different purity, Ni-200 ( 4000 ppm impurity), Ni-270 (200 ppm), and JM-Ni (30 ppm) was compared to that of TD-Ni (400 ppm with 24,000 ppm ThO₂). The samples were isothermally oxidized in slowly flowing air at 1050 and 1200°C. All nickels were oxidized with major surfaces either polished, ground, annealed at 1120°C and polished, or annealed at 1240°C and polished. Weight change, metal thickness loss, scale thickness, microstructure, and scale texture were examined. In weight change, metal loss, and scale thickness, the TD-Ni was nearly the same as the higher purity grades, JM-Ni and Ni-270, while Ni-200 oxidized approximately twice as much as the others. Grinding and annealing had only second order effects on these aspects of oxidation behavior. On the other hand, in scale microstructure and texture TD-Ni was similar to the lower purity Ni-200 while Ni-270 was similar to JM-Ni. Grinding did not affect the textures of JM-Ni or Ni-270, which Were (001), but changed the textures of Ni-200 and TD-Ni from (Oil) to (031). Annealing did not affect the microstructure of the oxide layers. A two-layer scale was observed only on the TD-Ni and Ni-200. The presence of ThO₂ in TD-Ni appears to act as an impurity in oxide scale orientation but does not substantially alter the extent of oxidation.     

Association cortex lesions and umweg behavior in cats.

Three groups of 7 cats were subjected to anterior or posterior association cortex lesions or sham lesions. Both anterior and posterior preparations were impaired in performance on the Hebb-Williams maze task, but did not differ significantly, thus supporting the argument of R. F. Thompson et al (1963) that structurally distinct association fields are equivalent parts of a general functional system. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)