NF94-179 Surge Irrigation Management

This NebFact discusses surge irrigation management

Elevation dynamics in a restored versus a submerging salt marsh in Long Island Sound

Accelerated sea-level rise (SLR) poses the threat of salt marsh submergence, especially in marshes that are relatively low-lying. At the same time, restoration efforts are producing new low-lying marshes, many of which are thriving and avoiding submergence. To understand the causes of these different fates, we studied two Long Island Sound marshes: one that is experiencing submergence and mudflat expansion, and one that is undergoing successful restoration. We examined sedimentation using a variety of methods, each of which captures different time periods and different aspects of marsh elevation change: surface-elevation tables, marker horizons, sediment cores, and sediment traps. We also studied marsh hydrology, productivity, respiration, nutrient content, and suspended sediment. We found that, despite the expansion of mudflat in the submerging marsh, the areas that remain vegetated have been gaining elevation at roughly the rate of SLR over the last 10 years. However, this elevation gain was only possible thanks to an increase in belowground volume, which may be a temporary response to waterlogging. In addition, accretion rates in the first half of the twentieth century were much lower than current rates, so century-scale accretion in the submerging marsh was lower than SLR. In contrast, at the restored marsh, accretion rates are now averaging about 10 mm yr-1 (several times the rate of SLR), much higher than before restoration. The main cause of the different trajectories at the two marshes appeared to be the availability of suspended sediment, which was much higher in the restored marsh. We considered and rejected alternative hypotheses, including differences in tidal flooding, plant productivity, and nutrient loading. In the submerging marsh, suspended and deposited sediment had relatively high organic content, which may be a useful indicator of sediment starvation

Location, Location, Location Should Be Environment, Environment, Environment : A Market-Based Tool to Simplify Environmental Considerations in Residential Real Estate

The most important rule of real estate (location, location, location) should be upgraded to the three E’s: environment, environment, environment. What we value in real estate is the natural and human environment of a site and its structures. A home is typically an American’s most significant asset; thus, environmental issues should be of interest, primarily because the effects of environmental degradation can cause devaluation while simultaneously imposing substantial expenses (such as cleanup, health care, and relocation) on the population. The real costs of ignoring the environment are life-threatening health and safety issues, including lung damage and cancer resulting from radon exposure, (which the EPA estimates kills 20,000 people per year), and indoor air pollution (from Volatile Organic Compounds (VOCs), for example), the effects of mold and polluted water, and heart and lung conditions related to poor air quality, result in thousands of premature deaths each year. Environmental issues include both anthropogenic sources and naturally occurring phenomena. The problem is that, for some buyers, sellers and professionals, obtaining accurate data is difficult. Many know there are issues, but they are unable to get straight-forward, manageable information. Some do not want to know of the issues, and others are overwhelmed. Complicating the matter for everyone is the reality that the laws related to disclosure and duties to prevent or mitigate harm vary significantly by jurisdiction, creating unpredictable rights and duties that range from caveat emptor to duties of reasonable inquiry. Consistency between jurisdictions is of greater importance than ever because of the mobility of the population. Even with guidance and reports from the EPA, the tools available to the majority of individuals seeking to make this most significant purchase, the real estate market does not address the health and safety risks caused by environmental degradation. Given this deficit in information, we propose a voluntary checklist to alert consumers, owners, and professionals of environmental issues that can impose significant costs for health care, remediation, and property devaluation. Knowledge of the issues should reduce disputes, and, over time, consumers may demand properties that are safer, with economic variables that are better quantified. That in turn should encourage sellers, builders and producers to satisfy the expectations of the consuming public with greener and more sustainable housing

NF94-177 Nebraska Surge Irrigation Trials

This NebFact discusses the Nebraska Surge Irrigation Trials

The pursuit of isotopic and molecular fire tracers in the polar atmosphere and cryosphere

We present an overview of recent multidisciplinary, multi-institutional efforts to identify and date major sources of combustion aerosol in the current and paleoatmospheres. The work was stimulated, in part, by an atmospheric particle \u27sample of opportunity\u27 collected at Summit, Greenland in August 1994, that bore the 14C imprint of biomass burning. During the summer field seasons of 1995 and 1996, we collected air filter, surface snow and snowpit samples to investigate chemical and isotopic evidence of combustion particles that had been transported from distant fires. Among the chemical tracers employed for source identification are organic acids, potassium and ammonium ions, and elemental and organic components of carbonaceous particles. Ion chromatography, performed by members of the Climate Change Research Center (University of New Hampshire), has been especially valuable in indicating periods at Summit that were likely to have been affected by the long range transport of biomass burning aerosol. Univariate and multivariate patterns of the ion concentrations in the snow and ice pinpointed surface and snowpit samples for the direct analysis of particulate (soot) carbon and carbon isotopes. The research at NIST is focusing on graphitic and polycyclic aromatic carbon, which serve as almost certain indicators of fire, and measurements of carbon isotopes, especially 14C, to distinguish fossil and biomass combustion sources. Complementing the chemical and isotopic record, are direct \u27visual\u27 (satellite imagery) records and less direct backtrajectory records, to indicate geographic source regions and transport paths. In this paper we illustrate the unique way in which the synthesis of the chemical, isotopic, satellite and trajectory data enhances our ability to develop the recent history of the formation and transport of soot deposited in the polar snow and ice

Chromosome Organization in Meiosis

Our objective is to understand the mechanics of homologous chromosome pairing during meiosis. Aberrant pairing can result in nondisjunction and birth defects in humans. This study used yeast, Saccharomyces cerevisiae, with chromosomally‐integrated arrays of tetO operators that bind TetR repressor proteins fused to GFP to produce a fluorescent signal. In diploid cells, the tetO/TetR‐GFP system allows homologous chromosomes to be identified as two foci (unpaired) or one focus (paired) as they progress through meiosis. We conducted three replicate timecourse experiments, analysing three different stages of meiosis, t=0 hours: pre‐meiotic, t=3 hours: pairing transition, and t=5 hours: synapsis. At each stage, the cells were imaged for 25 minutes, with z‐stacks taken at 30 second intervals. To analyse individual cells, we developed a 4D image analysis pipeline in MATLAB that allowed us to calculate the mean squared change in distance (MSCD), a metric describing the distance between two foci, and analyse deviations from normal diffusive motion

The Origin and Biosynthesis of the Benzenoid Moiety of Ubiquinone (Coenzyme Q) in \u3ci\u3eArabidopsis\u3c/i\u3e

It is not known how plants make the benzenoid ring of ubiquinone, a vital respiratory cofactor. Here, we demonstrate that Arabidopsis thaliana uses for that purpose two separate biosynthetic branches stemming from phenylalanine and tyrosine. Gene network modeling and characterization of T-DNA mutants indicated that acyl-activating enzyme encoded by At4g19010 contributes to the biosynthesis of ubiquinone specifically from phenylalanine. CoA ligase assays verified that At4g19010 prefers para-coumarate, ferulate, and caffeate as substrates. Feeding experiments demonstrated that the at4g19010 knockout cannot use para-coumarate for ubiquinone biosynthesis and that the supply of 4-hydroxybenzoate, the side-chain shortened version of para-coumarate, can bypass this blockage. Furthermore, a trans-cinnamate 4-hydroxylase mutant, which is impaired in the conversion of trans-cinnamate into para-coumarate, displayed similar defects in ubiquinone biosynthesis to that of the at4g19010 knockout. Green fluorescent protein fusion experiments demonstrated that At4g19010 occurs in peroxisomes, resulting in an elaborate biosynthetic architecture where phenylpropanoid intermediates have to be transported from the cytosol to peroxisomes and then to mitochondria where ubiquinone is assembled. Collectively, these results demonstrate that At4g19010 activates the propyl side chain of para-coumarate for its subsequent β-oxidative shortening. Evidence is shown that the peroxisomal ABCD transporter (PXA1) plays a critical role in this branch. Includes supplementary files

Synthetically Encoded Ultrashort-Channel Nanowire Transistors for Fast, Pointlike Cellular Signal Detection

Nanostructures, which have sizes comparable to biological functional units involved in cellular communication, offer the potential for enhanced sensitivity and spatial resolution compared to planar metal and semiconductor structures. Silicon nanowire (SiNW) field-effect transistors (FETs) have been used as a platform for biomolecular sensors, which maintain excellent signal-to-noise ratios while operating on lengths scales that enable efficient extra- and intracellular integration with living cells. Although the NWs are tens of nanometers in diameter, the active region of the NW FET devices typically spans micrometers, limiting both the length and time scales of detection achievable with these nanodevices. Here, we report a new synthetic method that combines gold-nanocluster-catalyzed vapor–liquid–solid (VLS) and vapor–solid–solid (VSS) NW growth modes to produce synthetically encoded NW devices with ultrasharp (<5 nm) n-type highly doped $(n^{++})$ to lightly doped (n) transitions along the NW growth direction, where $n^{++}$ regions serve as source/drain (S/D) electrodes and the n-region functions as an active FET channel. Using this method, we synthesized short-channel $n^{++}/n/n^{++}$ SiNW FET devices with independently controllable diameters and channel lengths. SiNW devices with channel lengths of 50, 80, and 150 nm interfaced with spontaneously beating cardiomyocytes exhibited well-defined extracellular field potential signals with signal-to-noise values of ca. 4 independent of device size. Significantly, these “pointlike” devices yield peak widths of $\sim 500 \mu s$, which is comparable to the reported time constant for individual sodium ion channels. Multiple FET devices with device separations smaller than $2 \mu m$ were also encoded on single SiNWs, thus enabling multiplexed recording from single cells and cell networks with device-to-device time resolution on the order of a few microseconds. These short-channel SiNW FET devices provide a new opportunity to create nanoscale biomolecular sensors that operate on the length and time scales previously inaccessible by other techniques but necessary to investigate fundamental, subcellular biological processes.Chemistry and Chemical BiologyEngineering and Applied Science