A physical model to determine snowfall over land by microwave radiometry

Falling snow is an important component of global precipitation in extratropical regions. This paper describes the methodology and results of physically based retrievals of snow falling over land surfaces. Because microwave brightness temperatures emitted by snow-covered surfaces are highly variable, precipitating snow above such surfaces is difficult to observe using window channels that occur at low frequencies (/spl nu/<100 GHz). Furthermore, at frequencies /spl nu//spl les/37 GHz, sensitivity to liquid hydrometeors is dominant. These problems are mitigated at high frequencies (/spl nu/>100 GHz) where water vapor screens the surface emission, and sensitivity to frozen hydrometeors is significant. However, the scattering effect of snowfall in the atmosphere at those higher frequencies is also impacted by water vapor in the upper atmosphere. The theory of scattering by randomly oriented dry snow particles at high microwave frequencies appears to be better described by regarding snow as a concatenation of "equivalent" ice spheres rather than as a sphere with the effective dielectric constant of an air-ice mixture. An equivalent sphere snow scattering model was validated against high-frequency attenuation measurements. Satellite-based high-frequency observations from an Advanced Microwave Sounding Unit (AMSU-B) instrument during the March 5-6, 2001 New England blizzard were used to retrieve snowfall over land. Vertical distributions of snow, temperature, and relative humidity profiles were derived from the Mesoscale Model (MM5) cloud model. Those data were applied and modified in a radiative transfer model that derived brightness temperatures consistent with the AMSU-B observations. The retrieved snowfall distribution was validated with radar reflectivity measurements obtained from a ground-based radar network.     

Illness perceptions, coping and functioning in patients with rheumatoid arthritis, chronic obstructive pulmonary disease and psoriasis

The present cross-sectional study analyzed the extent to which illness perceptions and coping strategies (as measured by the Illness Perception Questionnaire and the Utrecht Coping List, respectively) are associated with levels of daily functioning, as indicated by the Medical Outcomes Study SF-20, and disease-specific measures in 244 adults: 84 with rheumatoid arthritis (RA); 80 with chronic obstructive lung disease (COPD); and 80 with psoriasis. The results of stepwise regression analyses indicated that a strong illness identity, passive coping, belief in a long illness duration, belief in more severe consequences, and an unfavorable score on medical variables were associated with worse outcome on disease-specific measures of functioning and on general role and social functioning. Coping by seeking social support and beliefs in controllability/curability of the disease were significantly related to better functioning. The implications of these findings for future interventions and research are discussed.     

Radiative properties of deformed hydrometeors for commonly usedpassive microwave frequencies

Scattering parameters for ensembles of aspherical ice and liquid hydrometeors were calculated at an incidence angle (ψ) of 50° for frequencies of 10.7, 18.0, 37.0, 50.3, and 85.6 GHz. Hydrometeors are assumed to be oblate ellipsoids with semiminor axes aligned with ψ=0°. The angle ψ 50° is determined by the viewing angle of satellite-borne radiometers. The backscattering extinction coefficients at ψ=0° were also calculated at 18, 37, and 85.6 GHz to provide information for future nadir scanning satellite-borne radars. The hydrometeors are assumed to be characterized by Marshall-Palmer drop-size distributions. The extended boundary condition method is used to calculate the extinction and backscattering coefficients as well as the albedo for single scattering and the asymmetry factor of the phase function. Results are fitted to simple functions of the rainfall rate. Some comparisons illustrate the differences and similarities of these results with those obtained from equal volume spheres     

The impact of learning of a genetic predisposition to nicotine dependence: an analogue study

Design: Analogue study using four vignettes; 2 (genetic status) x 2 (whether treatment efficacy information provided) between subjects design.

Participants: 269 British adult smokers.

Outcome measures: Preferred cessation methods and perceived control over quitting.

Results: Gene positive participants were significantly more likely to choose the cessation method described as effective for their genetic status, but significantly less likely to choose to use their own willpower. Providing tailored treatment information did not alter these effects. Perceived control was not significantly affected by either genetic status or information provision.

Conclusions: Learning of a genetic predisposition to nicotine dependence may increase desire for effective cessation methods, but may undermine the perceived importance of willpower in stopping smoking.

     

World-wide lightning location using VLF propagation in the Earth-ionosphere waveguide

Worldwide lightning location (WWLL) using only 30 lightning sensors has been successfully achieved by using only VLF propagation in the Earth-ionosphere waveguide (EIWG). Ground propagation or mixed "sky" and ground propagation is avoided by requiring evidence of Earth-ionosphere waveguide dispersion. A further requirement is that the lightning strike must be inside the perimeter defined by the lightning sensor sites detecting the stroke. Under these conditions, the time and the location of the stroke can be determined, along with the rms errors. Lightning strokes with errors exceeding 30 Ps or To assist with identifying impulses from the same lightning stroke, the lightning sensor threshold is automatically adjusted to allow an average detection rate of three per second. This largely limits detection to the strongest 4% of all lightning strokes, of which about 40% meet the accuracy requirements for time and location.     

Psychiatric correlates of MR deep white matter lesions in probable Alzheimer's disease

The authors examined the relationship between psychiatric symptoms and the presence of of MR deep white matter lesions (DWMLs) in 28 probable Alzheimer's disease (AD) patients with mild to moderate dementia. The difference in frequency of psychiatric symptoms between patients with and without DWMLs was not statistically significant. However, MR global scores of severity correlated with the presence of ideational disturbances (such as low self-esteem and suicidal ideation). Analysis of specific cerebral regions indicated that the highest correlation occurred in the frontal white matter. Thus, DWMLs are correlated with specific symptoms of depression in AD. Whether DWMLs are etiologically related to these symptoms remains to be determined.     

Flushing history as a hydrogeological control on the regional distribution of arsenic in shallow groundwater of the Bengal Basin

Whereas serious health consequences of widespread consumption of groundwater elevated in As have been documented in several South Asian countries, the mechanisms responsible for As mobilization in reducing aquifers remain poorly understood. We document here a previously unrecognized and consistent relationship between dissolved As concentrations in reducing groundwater and the phosphate-mobilizable As content of aquifer sediment for a set of precisely depth-matched samples from across Bangladesh. The relationship holds across nearly 3 orders of magnitude in As concentrations and suggests that regional as well as local patterns of dissolved As in shallow groundwater are set by the solid phase according to a remarkably constant ratio of approximately 250 microg/L dissolved As per 1 mg/kg P-mobilizable As. We use this relationship in a simple model of groundwater recharge to propose that the distribution of groundwater As in shallow aquifers of the Bengal Basin could primarily reflect the different flushing histories of sand formations deposited in the region over the past several thousand years.     

Inducing assertive behavior in chronic schizophrenics: A comparison of socioenvironmental, desensitization, and relaxation therapies.

Assigned 63 20-67 yr. old male schizophrenics to 3 treatment conditions: socioenvironmental treatment, systematic desensitization, or relaxation training. It was predicted that socioenvironmental treatment would be more effective with older male schizophrenics (over 45 yr. of age) and systematic desensitization and relaxation training with younger male schizophrenics in generating assertive behavior. It was further anticipated that systematic desensitization and relaxation training would be generally superior in reducing anxiety. Results confirm the expectancy for older patients with respect to socioenvironmental treatment and assertive behavior. There were no other differential treatment effects, although all conditions did generate a decrease in anxiety. (PsycINFO Database Record (c) 2010 APA, all rights reserved)