Cambium

The Cambium investigation is one in a pair of investigations which utilizes the Advanced Biological Research System (ABRS). Cambium seeks definitive evidence that gravity has a direct effect on cambial cells (cells located under the inner bark where secondary growth occurs) in willow, Salix babylonica. The Cambium investigation uses willow plants flown on the International Space Station to better understand the fundamental processes by which plants produce cellulose and lignin, the two main structural materials found in plant matter. On Earth, the nature of wood within tree stems varies depending on position, and that within-tree variation includes differences in cell types and chemistry including lignin and cellulose, two major components of wood influencing wood strength, usefulness and carbon content. Reaction wood is an extreme example of such variation, and it is believed that reaction wood develops as a reaction to the influence of gravity. For the Cambium experiment, young willow plants will be launched to the ISS where their stems will be looped in an attempt to induce reaction wood formation. After on-orbit growth, the plants will be preserved and returned to Earth for analysis. Understanding the role of gravity in wood formation is expected to enable wiser management of forests for carbon sequestration as well as better utilization of trees for wood products. Detailed Research Description: The Cambium experiment will provide an understanding of physiological processes such as gene expression, metabolism and general plant development that are affected in plant systems exposed to space flight. Cambium seeks definitive evidence that gravity has a direct effect on the cambial cells (cells located under the inner bark where secondary growth occurs) that contribute to xylogenesis (reaction wood formation) in willow plants, Salix babylonica. Tension wood fibers differentiate on the upper sides of stems when the stem is altered from its normal (vertical) growth position by looping. This reaction wood response does not occur if the orientation of the plant stem with respect to gravity is not altered. If a localized zone of tension wood should be formed in looped stems under microgravity conditions, this would be the first conclusive evidence that gravity is not required. On the other hand, if a zone of tension wood is not produced in looped stems (subjected to tension on one side, compression on the other) in microgravity, this would be the first definitive evidence that gravity has a direct effect on the cambial cells which contribute to reaction wood formation. Following return to Earth the plants will be analyzed by microscopy and chemical methods

Characterizing Variability in the Transient Storage Zones of Miller Run in Lewisburg, PA

The transient storage zone processes are investigated in a small second order stream with a 2.2 square kilometer watershed. The presence of transient storage zones in small streams impacts the available flow paths for water and results in a wider range of residence times for water and dissolved chemicals than would be predicted by considering only the main channel flow path. Residence times can be used to quantify the health of a stream as several biogeochemical and ecological processes occur in water slowed by transient storage. Sections of the studied stream are impacted by varying types of stream restoration practices and watershed management practices. These practices lead to the presence of a wide range of transient storage zone types. A combination of data collection, field experimentation, and data analysis is used to characterize the variability in transient storage zone processes and residence times in the small stream and to relate the identified storage zone processes to physical characteristics of the stream. Field experimentation took place along measured sections and included geophysical investigations of the subsurface and continuous-injection tracer studies using a conservative tracer with sampling from the main channel flow and from identified transient storage zones following the continuous injection of tracer. Data analysis leads to a preliminary understanding of how various stream and watershed management practices can impact the presence of transient storage zones and the range of residence times and flow paths in small streams

A Model for Management Predictions of Territorial Bird Populations

Author Institution: Biomathematics Program, Department of Statistics, North Carolina State UniversityA model was developed to compare alternative management schemes that can be employed to regulate the population level of birds having a territorial or resource limited breeding organization. The alternatives of habitat modification, removal of birds, and sterilization were compared. The model is based on the dynamics of the female segment of the population, but provision is made in the case of sterilization for predicting the effects of treatment cither of females only or of both sexes

Breaking the Promise: The Burden of Unfunded Liabilities on Future Generations

This paper discusses the trillions of dollars in government debt accumulated by state governments as well as the costs of debt on future generations. It examines unfunded pension liabilities, unfunded other post-employment benefit (OPEB) liabilities, as well as state bonded obligations and the crowding out effect of public debt onto state budgets. The paper also discusses opportunities for reform that can help alleviate the debt burden on future generations. Data are collected from state annual comprehensive financial reports (ACFRs) as well as public pension and OPEB actuarial valuations

Wintertime Shoreward Near-Surface Currents South of Cape Hatteras

[1] Cross-isobath flow on continental shelves is of interest for a variety of reasons. Near Cape Hatteras, North Carolina, the transport of larval organisms, pollutants, and oceanic carbon budget constituents to and from the adjacent Albemarle and Pamlico Sounds may depend critically on cross-isobath currents. Shoreward currents in the near-surface waters south of Cape Hatteras are documented herein, on the basis of continuous 2-year time series, encompassing all or part of three consecutive winters. Energetic shoreward currents exist similar to30% of the time from midfall through late spring. These currents are evident over the 20 and 35 m isobaths along a mooring line situated similar to40 km southwestward from Cape Hatteras. Shoreward velocities average similar to12 cm/s, and events persist from 0.5 to 4 days, occurring every 2.5-5 days, except in summer. These events often coincide with southwestward winds but occur under both upwelling and downwelling favorable conditions, such that Ekman veering in the surface layer does not account for the shoreward velocities. In winter the mooring line south of Cape Hatteras is frequently traversed by a strong temperature and salinity front, with light, relatively fresh, cold, stratified water on one side, and denser, more saline, warmer, unstratified water on the other. Hydrography and satellite sea surface temperature imagery help identify this front as the boundary between South Atlantic Bight and Mid-Atlantic Bight coastal shelf waters, the Hatteras Front.\u27\u27 Flow along the Hatteras Front where it crosses the shelf appears to account for the observed shoreward currents. The along-shelf advection of the Hatteras Front may depend on both winds and Gulf Stream distance offshore

Priority Based Buffering over Multiple Lossy Links Using TCP Aware Layer Buffering

Wireless military information systems require high reliability, which is difficult to achieve in adverse conditions. To provide high reliability, one must overcome packet loss across multiple wireless hops. Buffering packets in a lossy environment is well explored; however, the ability to selectively buffer TCP traffic across multiple lossy links is a new area of research. This document seeks to explore the delivery of high priority traffic in a lossy environment and conclude that prioritized buffing can increase the probability that a high priority download will finish, where others will fail. It is shown that buffering provides six times the throughput in a network with each link experiencing 25% loss. Prioritizing TCP packet flows provides a varied outcome, as it cannot overcome the TCP mechanisms, when the packet loss recovery time is greater than the retransmission timeout event. However, the future work in chapter 6 may provide roadmap to gaining control authority of the challenged network

Determination of the urinary aglycone metabolites of vitamin K by HPLC with redox-mode electrochemical detection

We describe a method for the determination of the two major urinary metabolites of vitamin K as the methyl esters of their agyclone structures, 2-methyl-3-(3-3-carboxymethylpropyl)-1,4-naphthoquinone (5C-side-chain metabolite) and 2-methyl-3-(5-carboxy-3-methyl-2-pentenyl)-1,4-naphthoquinone (7C-side-chain metabolite), by HPLC with electrochemical detection (ECD) in the redox mode. Urinary salts were removed by reversed-phase (C18) solid phase extraction (SPE) and the predominately conjugated vitamin K metabolites hydrolysed with methanolic HCl. The resultant carboxylic acid aglycones were quantitatively methylated with diazomethane and fractionated by normal-phase (silica) SPE. Final analysis was by reversed-phase (C18) HPLC with a methanol-aqueous mobile phase. Metabolites were detected by amperometric, oxidative ECD of their quinol forms, which were generated by post-column coulometric reduction at an upstream electrode. The assay gave excellent linearity (r2 typically = 0.999) and high sensitivity with an on-column detection limit of <3.5 fmol (<1pg). The inter-assay precision was typically 10%. Metabolite recovery was compared to that of an internal standard (2-methyl-3-(7'-carboxy-heptyl)-1,4-naphthoquinone), added to urine samples just before analysis. Using this methodology we confirmed that the 5C- and 7C-metabolite were major catabolites of both phylloquinone (vitamin K1) and menaquinones (vitamin K2) in humans. We propose that the measurement of urinary vitamin K metabolite excretion is a candidate non-invasive marker of total vitamin K status

Some features of the upwelling off Oman

Hydrographic and ADCP data were collected in the coastal waters of Oman during the 1987 summer monsoon. The minimum surface temperatures, up to 5°C below ambient offshore values, were found close to the coast and in the vicinity of the Kuria Muria Islands. Strong surface gradients were observed near Ras al Hadd at the entrance to the Gulf of Oman where the geostrophic surface flow exceeded 1.0 m/s. The alongshore flux in the top 300 m of a region extending 100 km from the coast was estimated to be 10 × 106 m3/s. Evidence for an offshore filament of cool water was found in both current and temperature data