Baywatch practical automatic detection of intrusion over water

This paper describes one solution to the problem of providing Perimeter Intruder Detection, (PIDS), for sites whose boundary includes direct access from uncontrolled water. Two surveillance heads were proposed, each consisting of a TI camera and a Colour CCTV camera mounted on a pan and tilt unit     

Gravisensing: ionic responses, cytoskeleton and amyloplast behavior.

In Zea mays L., changes in orientation of stems are perceived by the pulvinal tissue, which responds to the stimulus by differential growth resulting in upward bending of the stem. Gravity is perceived in the bundle sheath cells, which contain amyloplasts that sediment to the new cell base when a change in the gravity vector occurs. The mechanism by which the mechanical signal is transduced into a physiological response is so far unknown for any gravity perceiving tissue. It is hypothesized that this involves interactions of amyloplasts with the plasma membrane and/or ER via cytoskeletal elements. To gain further insights into this process we monitored amyloplast movements in response to gravistimulation. In a pharmacological approach we investigated how the dynamics of plastid sedimentation are affected by actin and microtubule (MT) disrupting drugs. Dark grown caulonemal filaments of the moss Physcomitrella patens respond to gravity vector changes with a reorientation of tip growth away from the gravity vector. MT distributions in tip cells were monitored over time and MTs were seen to accumulate preferentially on the lower flank of the tip 30 min after a 90 degree turn. Using a self-referencing Ca2+ selective ion probe, we found that growing caulonemal filaments exhibit a Ca2+ influx at the apical dome, similar to that reported previously for other tip growing cells. However, in gravistimulated Physcomitrella filaments the region of Ca2+ influx is not confined to the apex, but extends about 60 micrometers along the upper side of the filament. Our results indicate an asymmetry in the Ca2+ flux pattern between the upper and side of the filament suggesting differential activation of Ca2+ permeable channels at the plasma membrane.     

Analysis of the Cyclotron Facility calibration and aircraft dosimetry results from the LIULIN-3M instrument.

The LIULIN-3M instrument is a further development of the LIULIN dosimeter-radiometer, used on the MIR spacestation during the 1988-1994 time period. The LIULIN-3M is designed for continuous monitoring of the radiation environment during the BION-12 satellite flight in 1999. A semiconductor detector with 1 mm thickness and cm2 area is contained in the instrument. Pulse high analysis technique is used to determine the energy losses in the detector. The final data from the instrument are the flux and the dose rate for the exposure time and 256 channels of absorbed dose spectra based on the assumption that the particle flux is normal to the detector. The LIULIN-3M instrument was calibrated by proton fluxes with different energies at the Indiana University Cyclotron Facility in June 1997 and had been used for radiation measurements during commercial aircraft flights. The calibration procedure and some flight results are presented in this paper.     

Closed and continuous algae cultivation system for food production and gas exchange in CELSS.

In CELSS (Controlled Ecological Life Support System), utilization of photosynthetic algae is an effective means for obtaining food and oxygen at the same time. We have chosen Spirulina, a blue-green alga, and have studied possibilities of algae utilization. We have developed an advanced algae cultivation system, which is able to produce algae continuously in a closed condition. Major features of the new system are as follows. (1) In order to maintain homogeneous culture conditions, the cultivator was designed so as to cause a swirl on medium circulation. (2) Oxygen gas separation and carbon dioxide supply are conducted by a newly designed membrane module. (3) Algae mass and medium are separated by a specially designed harvester. (4) Cultivation conditions, such as pH, temperature, algae growth rate, light intensity and quantity of generated oxygen gas are controlled by a computer system and the data are automatically recorded. This equipment is a primary model for ground experiments in order to obtain some design data for space use. A feasibility of algae cultivation in a closed condition is discussed on the basis of data obtained by use of this new system.     

Effects of bioreactor retention time on aerobic microbial decomposition of CELSS crop residues.

The focus of resource recovery research at the KSC-CELSS Breadboard Project has been the evaluation of microbiologically mediated biodegradation of crop residues by manipulation of bioreactor process and environmental variables. We will present results from over 3 years of studies that used laboratory- and breadboard-scale (8 and 120 L working volumes, respectively) aerobic, fed-batch, continuous stirred tank reactors (CSTR) for recovery of carbon and minerals from breadboard grown wheat and white potato residues. The paper will focus on the effects of a key process variable--bioreactor retention time--on response variables indicative of bioreactor performance. The goal is to determine the shortest retention time that is feasible for processing CELSS crop residues, thereby reducing bioreactor volume and weight requirements. Pushing the lower limits of bioreactor retention times will provide useful data for engineers who need to compare biological and physicochemical components. Bioreactor retention times were manipulated to range between 0.25 and 48 days. Results indicate that increases in retention time lead to a 4-fold increase in crop residue biodegradation, as measured by both dry weight losses and CO2 production. A similar overall trend was also observed for crop residue fiber (cellulose and hemicellulose), with a noticeable jump in cellulose degradation between the 5.3 day and 10.7 day retention times. Water-soluble organic compounds (measured as soluble TOC) were appreciably reduced by more than 4-fold at all retention times tested. Results from a study of even shorter retention times (down to 0.25 days), in progress, will also be presented.     

Optimization of moisture content for wheat seedling germination in a cellulose acetate medium for a space flight experiment.

The Porous Tube Plant Nutrient Delivery System (PTPNDS), a hydrophilic, microporous ceramic tube hydroponic system designed for microgravity, will be tested in a middeck locker of the Space Shuttle. The flight experiment will focus on hardware operation and assess its ability to support seed germination and early seedling growth in microgravity. The water controlling system of the PTPNDS hardware has been successfully tested during the parabolic flight of the KC-135. One challenge to the development of the space flight experiment was to devise a method of holding seeds to the cylindrical porous tube. The seed-holder must provide water and air to the seed, absorb water from the porous tube, withstand sterilization, provide a clear path for shoots and roots to emerge, and be composed of flight qualified materials. In preparation for the flight experiment, a wheat seed-holder has been designed that utilizes a cellulose acetate plug to facilitate imbibition and to hold the wheat seeds in contact with the porous tube in the correct orientation during the vibration of launch and the microgravity environment of orbit. Germination and growth studies with wheat at a range of temperatures showed that optimal moisture was 78% (by weight) in the cellulose acetate seed holders. These and other design considerations are discussed.     

DNA double strand break production and rejoining in V79 cells irradiated with light ions.

Low energy protons and other densely ionizing light ions are known to have RBE>1 for cellular end points relevant for stochastic and deterministic effects. The occurrence of a close relationship between them and induction of DNA dsb is still a matter of debate. We studied the production of DNA dsb in V79 cells irradiated with low energy protons having LET values ranging from 11 to 31 keV/micrometer, i.e. in the energy range characteristic of the Bragg peak, using the sedimentation technique. We found that the initial yield of dsb is quite insensitive to proton LET and not significantly higher than that observed with X-rays, in agreement with recent data on V79 cells irradiated with alpha particles of various LET up to 120 keV/micrometer. By contrast, RBE for cell inactivation and for mutation induction rises with the proton LET. In experiments aimed at evaluating the rejoining of dsb after proton irradiation we found that the amount of dsb left unrepaired after 120 min incubation is higher for protons than for sparsely ionizing radiation. These results indicate that dsb are not homogeneous with respect to repair and give support to the hypothesis that increasing LET leads to an increase in the complexity of DNA lesions with a consequent decrease in their repairability.     

Evaluation of EarthRadar unexploded ordnance testing at Fort A.P.Hill, Virginia

Previously, K. Bakhtar and E. Sagal [ibid. vol. 17, pp. 4-11, 2002] made remarkable claims for the performance of the Bakhtar Associates ground-penetrating radar (GPR) in detecting and classifying buried unexploded ordnance (UXO). In this article, we report the results of the series of blind tests on the EarthRadar carried out during the Fall of 2000 and Spring of 2001, which led to very different conclusions regarding the radar's performance. The contents of this article are excerpted from the final report on the testing, prepared by the Institute for Defense Analyses     

Estimation of risk based on multiple events in radiation carcinogenesis of rat skin.

In the multistage theory of carcinogenesis, cells progress to cancer through a series of discrete, irreversible, heritable genetic alterations or mutations. However data on radiation-induced cancer incidence in rat skin suggests that some part of an intermediate repairable alteration may occur. Data are presented on cancer induction in rat skin exposed to the following radiations: 1. an electron beam (LET=0.34 keV/um, 2. a neon ion beam (LET=25 keV/um and 3. an argon ion beam (LET=125 keV/um. The latter 2 beams were generated by the Bevalac at the Lawrence Berkeley Laboratory, Berkeley, CA. About 6.0 cm2 of skin was irradiated per rat. The rats were observed every 6 weeks for at least 78 weeks and tumors were scored at first occurrence. Several histological types of cancer, including squamous and basal cell carcinomas, were induced. The cancer yield versus radiation dose was fitted by the quadratic equation (Y(D)=CLD+BD2), and the parameters C and B were estimated for each type of radiation. Analysis of the DNA from the electron-induced carcinomas indicated that K-ras and/or c-myc oncogenes were activated in all tumors tested, although only a small proportion of neon-induced tumors showed similar activation. In situ hybridization indicated that the cancers contain subpopulations of cells with differing amounts of c-myc and H-ras amplification. The results are consistent with the idea that ionizing radiation produces carcinogenically relevant lesions via 2 repairable events at low LET and via a non-repairable, linked event pathway at high LET; either pathway may advance the cell by 1 stage in the multistage model. The model, if validated, permits the direct calculation of cancer risk in rat skin in a way that can be subjected to experimental testing.