A feasibility study of signal processing to improve antenna gain Final report

Feasibility of signal processor with phase isolator for adaptive antenna arra

Eyespot configuration and predator approach direction affect the antipredator efficacy of eyespots

Many prey species possess eyespots: paired markings that often consist of two or more concentric circles. Predators are wary of such prey because eyespots are conspicuous and/or mistaken for vertebrate eyes. Here we used naïve domestic chicks as predators of artificial moth-like prey to test the hypothesis that both eyespots configuration and predator approach direction affect the antipredator efficacy of eyespots. We found that when chicks approached prey straight on, eyespots configuration did not influence attack latency. Chicks that approached from either the left or the right, were slower to attack prey in which the central circle of the eyespot was centrally placed or shifted in the direction of the chick’s approach, compared to prey in which the central circle had been shifted away from the direction of approach. These findings suggest that eyespots composed of concentric circles may protect prey against predators approaching from a wider range of directions than eyespots composed of eccentric circles. They are also consistent with the idea that eyespots are mistaken for eyes, and are perceived to pose a lesser risk when their “gaze” is averted from the approaching predator.</jats:p

Study of a signal processor employing a synthetic phase isolator

Evaluation of signal data processor employing synthetic phase isolator techniqu

Synthesis of calculational methods for the design and analysis of radiation shields for nuclear rocket systems. Volume 1 - Radiation measurements in a nuclear rocket propellant tank mockup using simulated liquid hydrogen

Calculational methods for nuclear rocket radiation shield design - radiation measurements in nuclear rocket propellant tank mockup using simulated liquid hydroge

Dynamical behavior of interacting dark energy in loop quantum cosmology

The dynamical behaviors of interacting dark energy in loop quantum cosmology are discussed in this paper. Based on defining three dimensionless variables, we simplify the equations of the fixed points. The fixed points for interacting dark energy can be determined by the Friedmann equation coupled with the dynamical equations {in Einstein cosmology}. But in loop quantum cosmology, besides the Friedmann equation, the conversation equation also give a constrain on the fixed points. The difference of stability properties for the fixed points in loop quantum cosmology and the ones in Einstein cosmology also have been discussed.Comment: 7 pages, 5 figure

Discriminating Stay-Green Grasses Using Hyperspectral Imaging and Chemometrics

Screening of plant collections for traits can be expensive, in terms of the number of plants to be screened, the duration of the plant lifecycle and the required observations. This study describes the application of a non-invasive method, hyperspectral imaging, combined with multivariate analysis, to distinguish between homozygous wild-type (YY) Lolium multiflorum and Lolium multiflorum F2 back cross plants heterozygous for y, a recessive Festuca pratensis stay-green gene (Thomas et al., 1997)

DC and Structured Electric Fields Observed on the C/NOFS Satellite and Their Association with Longitude, Plasma Density, and Solar Activity

Observations of DC electric fields and associated E x B plasma drifts gathered by the Vector Electric Field Investigation (VEFI) on the Air Force Communication/Navigation Outage Forecasting System (C/NOFS) satellite are presented. We show statistical averages of the vector fields and resulting E x B plasma flows for the first three years of operations as a function of season, longitude, local time, and Fl 0.7 conditions. Magnetic field data from the VEFI science magnetometer are used to compute the plasma flows. Although typically displaying eastward and outward-directed fields during the day and westward and downward-directed fields at night, the data from DC electric field detector often reveal variations from this pattern that depend on longitude, solar activity, and plasma density. Clear "wave-4" tidal effects in both electric field components have been detected and will be presented. Zonal plasma drifts show a marked variation with solar activity and may be used as a proxy for neutral winds at night. Evidence for pre-reversal enhancements in the meridional drifts that depend on solar activity is present for some longitudes, and are corroborated by clear evidence in the plasma density data that the spacecraft journeyed below the F-peak during evenings when the rise in the ionosphere is most pronounced. In addition to DC electric fields, the data reveal considerable electric field structures at large scales (approx 100's of km) that are usually confined to the nightside. Although such electric field structures are typically associated with plasma density depletions and structures, what is surprising is the number of cases in which large amplitude, structured DC electric fields are observed without a significant plasma density counterpart structure, including their appearance at times when the ambient plasma density appears relatively quiescent. We investigate the mapping of structured electric fields along magnetic field lines from distant locations and consider tropospheric thunderstorm sources to explain some of the observations. The dependence of the structuring on season and solar activity will be reported and discussed

Diagnostic accuracy of PAT-POPS and ManChEWS for admissions of children from the emergency department

Background The Pennine Acute Trust (PAT) Paediatric Observation Priority Score (PAT-POPS) is a specific emergency department (ED) physiological and observational aggregate scoring system, with scores of 0–18. A higher score indicates greater likelihood of admission. The Manchester Children’s Early Warning System (ManChEWS) assesses six physiological observations to create a trigger score, classified as Green, Amber or Red. Methods Prospectively collected data were used to calculate PAT-POPS and ManChEWS on 2068 patients aged under 16 years (mean 5.6 years, SD 4.6) presenting over 1 month to a UK District General Hospital Paediatric ED. Receiver operating characteristics (ROC) comparison, using STATA V.13, was used to investigate the ability of ManChEWS and PAT-POPS to predict admission to hospital within 72 h of presentation to the ED. Results Comparison of the area under the ROC curve indicates that the ManChEWS ROC is 0.67 (95% CI 0.64 to 0.70) and the PAT-POPS ROC is 0.72 (95% CI 0.68 to 0.75). The difference is statistically significant. At a PAT-POPS cut-off of ≥2, 80% of patients had their admission risk correctly classified ( positive likelihood ratio 3.40, 95% CI 2.90 to 3.98) whereas for ManChEWS with a cut off of ≥Amber only 71% of patients were correctly classified ( positive likelihood ratio 2.18, 95% CI 1.94 to 2.45). Conclusions PAT-POPS is a more accurate predictor of admission risk than ManChEWS. Replacing ManChEWS with PAT-POPS would appear to be clinically appropriate in a paediatric ED. This needs validation in a multicentre study

Electric Field and Plasma Density Observations of Irregularities and Plasma Instabilities in the Low Latitude Ionosphere Gathered by the C/NOFS Satellite

The Vector Electric Field Investigation (VEFI) on the C/NOFS equatorial satellite provides a unique data set which includes detailed measurements of irregularities associated with the equatorial ionosphere and in particular with spread-F depletions. We present vector AC electric field observations gathered on C/NOFS that address a variety of key questions regarding how plasma irregularities, from meter to kilometer scales, are created and evolve. The talk focuses on occasions where the ionosphere F-peak has been elevated above the C/NOFS satellite perigee of 400 km as solar activity has increased. In particular, during the equinox periods of 2011, the satellite consistently journeyed below the F-peak whenever the orbit was in the region of the South Atlantic anomaly after sunset. During these passes, data from the electric field and plasma density probes on the satellite have revealed two types of instabilities which had not previously been observed in the C/NOFS data set: The first is evidence for 400-500km-scale bottomside "undulations" that appear in the density and electric field data. In one case, these large scale waves are associated with a strong shear in the zonal E x B flow, as evidenced by variations in the meridional (outward) electric fields observed above and below the F-peak. These undulations are devoid of smaller scale structures in the early evening, yet appear at later local times along the same orbit associated with fully-developed spread-F with smaller scale structures. This suggests that they may be precursor waves for spread-F, driven by a collisional shear instability, following ideas advanced previously by researchers using data from the Jicamarca radar. A second result is the appearance of km-scale irregularities that are a common feature in the electric field and plasma density data that also appear when the satellite is near or below the F-peak at night. The vector electric field instrument on C/NOFS clearly shows that the electric field component of these waves is strongest in the zonal direction. These waves are strongly correlated with simultaneous observations of plasma density oscillations and appear both with, and without, evidence of larger-scale spread-F depletions. These km-scale, quasi-coherent waves strongly resemble the bottomside, sinusoidal irregularities reported in the Atmosphere Explorer satellite data set by Valladares et al. and are believed to cause scintillations of VHF radiowaves. We interpret these new observations in terms of fundamental plasma instabilities associated with the unstable, nighttime equatorial ionosphere