Development of a CELSS Experimental Facility

A CELSS Experimental Facility was developed two years ago. It contains a volume of about 40.0 m³ and a cultivating area of about 8.4 m²; its interior atmospheric parameters such as temperature, relative humidity, oxygen concentration, carbon dioxide concentration, total pressure, lighting intensity, photoperiod, water content in the growing-matrix, CO₂-added accumulative amount, O₂-released accumulative amount and ethylene concentration are all controlled and logged automatically and effectively; its growing system consists of two rows of racks along its left-and-right sides separately, each side holds two upper-and-lower layers, and the vertical distance of each growing bed can be adjusted automatically and independently; lighting sources consist of both red (95%) and blue (5%) light-emitting diodes (LED), and the average lighting intensity of each lamp bank at 20-cm distance position under it, reaches to 255.0 μmol m⁻² s⁻¹. After that, demonstrating tests were carried out and were finally followed by growing lettuce in the facility. The results showed that all subsystems operated well and all parameters were controlled automatically and efficiently. The lettuce plants in the system could grow much well. Successful development of this system laid a necessary foundation for future larger-scale studies on CELSS integration technique.     

Multiple-model estimation with variable structure. V. Likely-modelset algorithm

For pt. IV see ibid., vol. 35, no. 1, p. 242-254 (1999). A multiple-model (MM) estimator with a variable structure, called likely-model set (LMS) algorithm, is presented, which is generally applicable to most hybrid estimation problems and is easily implementable. It uses a set of models that are not unlikely to match the system mode in effect at any given time. Different versions of the algorithm are discussed. The model set is made adaptive in the simplest version by deleting all unlikely models and activating all models to which a principal model may jump so as to anticipate the possible system mode transitions. The generality, simplicity, and ease in the design and implementation of the LMS estimator are illustrated via an example of tracking a maneuvering target and an example of fault detection and identification. Comparison of its cost-effectiveness with other fixed- and variable-structure MM estimators is given     

Solar neutron events as a tool to study particle acceleration at the Sun

The Sun provides unique opportunities to study particle acceleration mechanisms using data from detectors placed on the Earth’s surface and on board spacecrafts. Particles may gain high energies by several physical mechanisms. Differentiating between these possibilities is a fundamental problem of cosmic ray physics. Energetic neutrons provide us with information that keeps the signatures of the acceleration site. A summary of some representative solar neutron events observed on the Earth’s surface, including associated X and γ-ray observations from spacecrafts is presented. We discuss evidence of acceleration of particles by the Sun to energies up to several tens of GeV. In addition, a recent solar neutron event that occurred on September 7th 2005 and detected by several observatories at Earth is analyzed in detail.     

Survey of maneuvering target tracking. Part I. Dynamic models

This is the first part of a comprehensive and up-to-date survey of the techniques for tracking maneuvering targets without addressing the so-called measurement-origin uncertainty. It surveys various mathematical models of target motion/dynamics proposed for maneuvering target tracking, including 2D and 3D maneuver models as well as coordinate-uncoupled generic models for target motion. This survey emphasizes the underlying ideas and assumptions of the models. Interrelationships among models and insight to the pros and cons of models are provided. Some material presented here has not appeared elsewhere.     

Tracker design based on target perceivability

Theoretical design of a tracker with respect to the so-called target perceivability is presented. Basic rules and analytic formulas for the determination of tracker parameters are presented for making better tracking decisions (i.e., track initiation, confirmation, and termination) toward enhancing tracking performance. Simulation results are provided that support the theoretical design and demonstrate the enhancement of the tracker in tracking performance     

II: SOLID EARTH PHYSICS: Long Wavelength Sea Level and Solid Surface Perturbations Driven by Polar Ice Mass Variations: Fingerprinting Greenland and Antarctic Ice Sheet Flux

Rapid ice mass variations within the large polar ice sheets lead to distinct and highly non-uniform sea-level changes that have come to be known as ‘sea-level fingerprints’. We explore in detail the physics of these fingerprints by decomposing the total sea-level change into contributions from radial perturbations in the two bounding surfaces: the geoid (or sea surface) and the solid surface. In the case of a melting event, the sea-level fingerprint is characterized by a sea-level fall in the near-field of the ice complex and a gradually increasing sea-level rise (from 0.0 to 1.3 times the eustatic value) as one considers sites at progressively greater distances (up to ≈ 90° or so) from the ice sheet. The far-field redistribution is largely driven by the relaxation of the sea-surface as the gravitational pull of the ablating ice sheet weakens. The near-field sea-level fall is a consequence of both this relaxation and ocean-plus-ice unloading of the solid surface. We argue that the fingerprints provide a natural explanation for geographic variations in sea-level (e.g., tide gauge, satellite) observations. Therefore, they furnish a methodology for extending traditional analyses of these observations to estimate not only the globally averaged sea-level rate but also the individual contributions to this rate (i.e., the sources). This revised version was published online in August 2006 with corrections to the Cover Date.     

Applications of level crossing theory to target intervisibility: to be seen or not to be seen?

Here we discuss intervisibility (the existence of an unobstructed line of sight (LOS) between two points) accounting for the vertical and horizontal errors in the estimated locations of both points as well as elevation errors in the database of the terrain that could obstruct the LOS between these points. The errors are first simply treated as a "white" noise sequence: we assume no correlation between the intervisibility at two different times, and the probability of an instantaneous intervisibility event is in this case developed. This is useful; but perhaps of greater concern is whether or not a target remains visible long enough and/or often enough that its motion can be tracked? Consequently, we present a second treatment in which the errors are stochastic processes of a certain bandwidth, and both the probability density function (pdf) of an intervisibility interval and the average number of intervisibility intervals over a certain time period are developed.     

Protective effects of melatonin against C beam irradiation-induced oxidative stress and DNA injury in the mouse brain

The purpose of this experiment was to estimate the protective effects of melatonin against radiation-induced brain damages in mice induced by heavy ion beams. Kun-Ming mice were randomly divided into five groups: normal control group, irradiation control group, and three different doses of melatonin (5, 10, and 20 mg/kg, i.p.) treated groups. Apart from the normal control group, the other four groups were exposed to whole-body 4.0 Gy carbon ion beam irradiation (approximately 0.5 Gy/min) after i.p. administration of normal saline or melatonin 1 h before irradiation. The oxidative redox status of brain tissue was assessed by measurement of malondiadehyde (MDA) levels, total superoxide dismutase (T-SOD), cytosolic superoxide dismutase (Cu/ZnSOD, SOD1) and mitochondrial superoxide dismutase (MnSOD, SOD2) activities at 8 h after irradiation. DNA damages were determined using the Comet assay and apoptosis and cell cycle distribution were detected by flow cytometric analyses. A dramatic dose-dependent decrease in MDA levels, tail moment, rates of tailing cells, and apoptosis, and a dose-dependent increase in T-SOD and SOD2 activities, in brain tissues in the melatonin-treated groups were detected compared with the irradiation only group. Furthermore, flow cytometric analysis demonstrated that the percentage of brain cells in the G0/G1 phase decreased significantly, while those in the S and G2/M stage increased dramatically, with mice pretreated with melatonin compared to the irradiation control group. These data indicate that melatonin has protective effects against irradiation-induced brain injury, and that its underlying protective mechanisms may relate to modulation of oxidative stress induced by heavy ionirradiation.