Continuous hydroponic wheat production using a recirculating system

Continuous crop production, where plants of various ages are growing simultaneously in a single recirculating nutrient solution, is a possible alternative to batch production in a Controlled Ecological Life Support System. A study was conducted at John F. Kennedy Space Center where 8 trays (0.24 sq m per tray) of Triticum aestivum L. Yecora Rojo were grown simultaneously in a growth chamber at 23 C, 65 percent relative humidity, 1000 ppm CO2, continuous light, with a continuous flow, thin film nutrient delivery system. The same modified Hoagland nutrient solution was recirculated through the plant trays from an 80 L reservoir throughout the study. It was maintained by periodic addition of water and nutrients based on chemical analyses of the solution. The study was conducted for 216 days, during which 24 trays of wheat were consecutively planted (one every 9 days), 16 of which were grown to maturity and harvested. The remaining 8 trays were harvested on day 216. Grain yields averaged 520 g m(exp -2), and had an average edible biomass of 32 percent. Consecutive yields were unaffected by nutrient solution age. It was concluded that continual wheat production will work in this system over an extended period of time. Certain micronutrient deficiencies and toxicities posed problems and must be addressed in future continuous production systems

Making Deflection the New Diversion for Drug Offenders

The argument unfolds as follows. In Part I, we describe the origins and operation of deflection programs that currently exist in the United States and present the published empirical evidence about their effect on recidivism rates, as well as police and user population responses to them. We specifically discuss the LEAD template from Seattle, in addition to other models in Massachusetts and Texas. In Part II, we take a closer look at how conventional policing differs from the pre-arrest diversion program that was recently instituted in Atlanta. Using data from an original dataset of all 2012 felony drug arrests in Atlanta, we contrast the conventional approach to handling drug possession cases to the pre-arrest diversion approach and speculate about the savings that might have accrued had pre-arrest diversion been implemented years earlier. In Part III, we argue that prosecutors ought to become participants in and champions of county-wide deflection partnerships. As New Jersey\u27s Burlington County Prosecutor\u27s Office is the national leader in this effort, features of the Burlington program appear prominently in this discussion. We conclude on a comparative note, assessing how deflection measures up against conventional prosecution, diversion, and non-prosecution of substance users

Infrared High-Resolution Spectroscopy of Post-AGB Circumstellar Disks. I. HR 4049 - The Winnowing Flow Observed?

High-resolution infrared spectroscopy in the 2.3-4.6 micron region is reported for the peculiar A supergiant, single-lined spectroscopic binary HR 4049. Lines from the CO fundamental and first overtone, OH fundamental, and several H2O vibration-rotation transitions have been observed in the near-infrared spectrum. The spectrum of HR 4049 appears principally in emission through the 3 and 4.6 micron region and in absorption in the 2 micron region. The 4.6 micron spectrum shows a rich 'forest' of emission lines. All the spectral lines observed in the 2.3-4.6 micron spectrum are shown to be circumbinary in origin. The presence of OH and H2O lines confirm the oxygen-rich nature of the circumbinary gas which is in contrast to the previously detected carbon-rich material. The emission and absorption line profiles show that the circumbinary gas is located in a thin, rotating layer near the dust disk. The properties of the dust and gas circumbinary disk and the spectroscopic orbit yield masses for the individual stars, M_AI~0.58 Msolar and M_MV~0.34 Msolar. Gas in the disk also has an outward flow with a velocity of $\gtrsim$ 1 km/s. The severe depletion of refractory elements but near-solar abundances of volatile elements observed in HR 4049 results from abundance winnowing. The separation of the volatiles from the grains in the disk and the subsequent accretion by the star are discussed. Contrary to prior reports, the HR 4049 carbon and oxygen isotopic abundances are typical AGB values: 12C/13C=6^{+9}_{-4} and 16O/17O>200.Comment: 42 pages, 14 figures, Accepted by Ap

The Observed Trend of Boron and Oxygen in Field Stars of the Disk

Oxygen abundances are derived in a sample of 13 field F and G dwarfs and subgiants with metallicities in the range of -0.75 < [Fe/H] < +0.15. This is the same sample of stars for which boron abundances have been derived earlier from archived spectra obtained with the Hubble Space Telescope. In a log-log comparison of the B versus the O abundances, a slope of m(BO)=1.39 is found, indicating that in the disk, the abundance of B relative to O is intermediate between primary and secondary production (hybrid behavior). This relation of B versus O for disk stars is compared to the same relation for halo stars.Comment: 14 pages, 3 figures, 1 table. In press to The Astronomical Journal (July 2001

GaAs interfacial self-cleaning by atomic layer deposition

The reduction and removal of surface oxides from GaAs substrates by atomic layer deposition (ALD) of Al2O3 and HfO2 are studied using in situ monochromatic x-ray photoelectron spectroscopy. Using the combination of in situ deposition and analysis techniques, the interfacial "self-cleaning" is shown to be oxidation state dependent as well as metal organic precursor dependent. Thermodynamics, charge balance, and oxygen coordination drive the removal of certain species of surface oxides while allowing others to remain. These factors suggest proper selection of surface treatments and ALD precursors can result in selective interfacial bonding arrangements

Making Deflection the New Diversion for Drug Offenders

The argument unfolds as follows. In Part I, we describe the origins and operation of deflection programs that currently exist in the United States and present the published empirical evidence about their effect on recidivism rates, as well as police and user population responses to them. We specifically discuss the LEAD template from Seattle, in addition to other models in Massachusetts and Texas. In Part II, we take a closer look at how conventional policing differs from the pre-arrest diversion program that was recently instituted in Atlanta. Using data from an original dataset of all 2012 felony drug arrests in Atlanta, we contrast the conventional approach to handling drug possession cases to the pre-arrest diversion approach and speculate about the savings that might have accrued had pre-arrest diversion been implemented years earlier. In Part III, we argue that prosecutors ought to become participants in and champions of county-wide deflection partnerships. As New Jersey\u27s Burlington County Prosecutor\u27s Office is the national leader in this effort, features of the Burlington program appear prominently in this discussion. We conclude on a comparative note, assessing how deflection measures up against conventional prosecution, diversion, and non-prosecution of substance users