Microwave emission from an irregular snow layer

Emission from an irregular snow layer is modeled by a layer of Mie scatterers using the radiative transfer method. Comparisons are made with measurements showing snow wetness effects and rough air-snow boundary effects. For convenience of reference, theoretical model behavior is also illustrated.     

Optical crosstalk-induced switching between bistable soliton states

It is shown that the controlled use of optical crosstalk can induce switching between bistable soliton states in a fiber whose intensity-dependent refractive index is described by the linear plus smooth step model. The closely related phenomena of soliton fission, soliton fusion, radiation stripping, and the soliton transparency-extinction transition are also examined. The evanescently coupled model equations use are discussed, and numerical results are given. It is stressed that the general features of the crosstalk-induced switching and related phenomena do not depend on the specific nonlinearity (the LSS model) chosen     

Simulation of bit error performance of FSK, BPSK, and π/4 DQPSKin flat fading indoor radio channels using a measurement-based channelmodel

The results of a simulation study that provides insight into the simulation methodology and bit error rate (BER) performance of frequency-shift keying (FSK), binary phase-shift keying (BPSK), and π/4 differential phase-shift keying (π/4 DQPSK) in flat fading channels inside open plan buildings are presented. A detailed measurement-based propagation channel model, SIRCIM (simulation of indoor radio channel impulse response models), which generates over 1000 closely spaced baseband equivalent complex impulse responses for a mobile radio operating at 1.3 GHz and traveling over a 1-m path, is used. The small-scale channel model, the communication system models used in the analysis and the methods used to predict BER are described. The channel simulator and the systems models have been thoroughly tested, and results from average instantaneous BER simulations are shown. The BER performances of the modulation techniques are presented. It is found that BPSK offers between a 2.8-dB and 3.0-dB improvement over π/4 DQPSK, although the latter offers a 3-dB increase in capacity for a given spectrum allocation     

Modified Microtiter count method for viable cell counts from pure cultures and food model samples

A modified Microtiter count method was designed to assess viable cell counts in a rapid, easy, and accurate way. A Spiral plate method was used for comparison with the modified Microtiter count method. There was a strong correlation between the two methods in microbial counts from pure cultures (Escherichia coli O157:H7, R²=0.984; Salmonella enterica serovar Enteritidis, R²=0.995; and Listeria monocytogenes, R²=0.994) and food samples (R²=0.897). This study suggests that a modified Microtiter count method can be used to determine viable bacterial cell counts.     

Phenomenon of skipping sparks in discharges on a dielectric surface

Gliding sparks are associated with channel breakdown in air near a corona precharged dielectric layer backed by ground. Characterized by high current, their bright channels usually end in sudden branching/dimming. Infrequently, there occur cases in which channel brightness is interrupted, with no evident local branching but a new leader continuing on propagating after momentary delay. This skipping-spark phenomenon has been studied in an experimental system intended for taking Kirlian photographs. Operated in a Lichtenberg-figure mode, the method yields evidence in some detail. The authors report on observations of spark-channel touchdown and subsequent rebounding. A model based on nonuniform surface charging is proposed for explanation     

T c trend in high-T c superconductors

In our previous works, we have shown that most existing ceramic superconductors can be considered to be built of superconductor-semiconductor composite and we have estimated the change in phonon spectrum of the intrinsic superconductor unit if a semiconductor unit is attached to it. Moreover, the proximity effect under the size quantization condition has been examined in the superconductor-semiconductor composite. Each of the stated effects by itself could causeT _c enhancement in general as more semiconductor blocks are added to the system. We extend our study in this paper to analyze the combined actions of phonon spectral change and proximity effect without size quantization condition onT _c variation in members of the Tl₁ series of high-T _c superconductors. Our results indicate that an optimumT _c is obtained if the stated effects are included in the idealized unit cells of the superconductors made up of a superconductor-semiconductor array.     

A reevaluation of Stogryn's apparent temperature theory over the sea surface

The emission theory for the sea surface by Stogryn has been reevaluated. Results agree with Stogryn's paper except for small nadir angles where the apparent temperature versus win speed behavior is in reverse of what was reported by Stogryn. By plotting the change in contributions by the sea surface emission and sky temperature scattered toward the radiometer as a function of nadir angle at two different wind speeds, it is found that the sky temperature effect is dominating at small nadir angles, while the change in surface emission becomes increasingly more important at larger nadir angles. It is also found that at nadir higher emission is associated with the polarization whereoverrightarrow{E}field is aligned along the upwind direction than the one along the crosswind direction.     

The worst combinations of child abuse and neglect

We have studied the impact of various kinds of abuse and neglect on the child's perception of himself and his future. We found, when considering physical abuse, physical neglect, verbal abuse, emotional neglect, and sexual abuse, that less than 5% of these mistreatments occurred in isolation. Since the vast majority of mistreated children are subject to more than one kind of abuse or neglect, it was important to delineate which combinations have the greatest effect. We found that a combination of physical neglect, physical abuse, and verbal abuse had the greatest impact on children, affecting such things as their enjoyment of living and hopes for the future. An early age of onset for verbal abuse and emotional neglect was significantly associated with greater severity and frequency of mistreatment. Neglect appears to be a precursor to abuse in many cases.