Microwave radiative transfer studies of precipitation

Since the deployment of the DMSP SSM/I microwave imagers in 1987, increased utilization of passive microwave radiometry throughout the 10 - 100 GHz spectrum has occurred for measurement of atmospheric constituents and terrestrial surfaces. Our efforts have focused on observations and analysis of the microwave radiative transfer behavior of precipitating clouds. We have focused particular attention on combining both aircraft and SSM/I radiometer imagery with ground-based multiparameter radar observations. As part of this and the past NASA contract, we have developed a multi-stream, polarized radiative transfer model which incorporates scattering. The model has the capability to be initialized with cloud model output or multiparameter radar products. This model provides the necessary 'link' between the passive microwave radiometer and active microwave radar observations. This unique arrangement has allowed the brightness temperatures (TB) to be compared against quantities such as rainfall, liquid/ice water paths, and the vertical structure of the cloud. Quantification of the amounts of ice and water in precipitating clouds is required for understanding of the global energy balance

Optical radiation from the Crab pulsar

Possible mechanisms for producing the optical radiation from the Crab pulsar are proposed and discussed. There are severe difficulties in interpreting the radiation as being produced by an incoherent process, whether it be synchrotron radiation, inverse-Compton radiation or curvature radiation. It is proposed therefore that radiation in the optical part of the spectrum is coherent. In the polar cap model, a small bunch of electrons and positrons forms near each primary electron as a result of the pair-production cascade process. Ambient electric fields give rise to energy separation, as a result of which either the electrons or positrons will dominate the radiation from each bunch. The roll-off in the infrared is ascribed to synchrotron absorption by electrons and positrons located between the surface of the star and the force-balance radius. Various consequences of this model, which may be subjected to observational test, are discussed

Exploiting the full power of temporal gene expression profiling through a new statistical test: Application to the analysis of muscular dystrophy data

Background: The identification of biologically interesting genes in a temporal expression profiling dataset is challenging and complicated by high levels of experimental noise. Most statistical methods used in the literature do not fully exploit the temporal ordering in the dataset and are not suited to the case where temporal profiles are measured for a number of different biological conditions. We present a statistical test that makes explicit use of the temporal order in the data by fitting polynomial functions to the temporal profile of each gene and for each biological condition. A Hotelling T2-statistic is derived to detect the genes for which the parameters of these polynomials are significantly different from each other. Results: We validate the temporal Hotelling T2-test on muscular gene expression data from four mouse strains which were profiled at different ages: dystrophin-, beta-sarcoglycan and gammasarcoglycan deficient mice, and wild-type mice. The first three are animal models for different muscular dystrophies. Extensive biological validation shows that the method is capable of finding genes with temporal profiles significantly different across the four strains, as well as identifying potential biomarkers for each form of the disease. The added value of the temporal test compared to an identical test which does not make use of temporal ordering is demonstrated via a simulation study, and through confirmation of the expression profiles from selected genes by quantitative PCR experiments. The proposed method maximises the detection of the biologically interesting genes, whilst minimising false detections. Conclusion: The temporal Hotelling T2-test is capable of finding relatively small and robust sets of genes that display different temporal profiles between the conditions of interest. The test is simple, it can be used on gene expression data generated from any experimental design and for any number of conditions, and it allows fast interpretation of the temporal behaviour of genes. The R code is available from V.V. The microarray data have been submitted to GEO under series GSE1574 and GSE3523

Anticathepsin D Antibody-Sepharose Chromatography of Human Cathepsin D

Cathepsin D was isoilated from human tissues by anticatheipsin D antibo:dy-Serpharose 4B .chromatoigraphy. Caithepsin D, rele1ased from the immunoaffinity column formed one precipitin line with specif.ic antibody in immwnod:Lffusion and in immunoe1ectropholl1esis. The isolated proteinase is shown to be prure cathepsin D by actiivity and by inhibition with peipstatin. The quanititative determinati.on o:f cathepsin D in human tissue, taiken by bio.psy from sco,Uotic patients 1rl ivery small amount, is desert.bed. It was demonstrated that cathepsin D from human muscle and human gingival fluid was indistinguishable in immunodiffus ion from the human liver catheps iirl D

Isolation of Cathepsin Band a-N-Benzoylarginine-B-naphthylamide Hydrolase by Covalent Chromatography on Activated Thiol Sepharose

Cathepsin Band a-N-benzoylarginine-P,-naphthylamide (BANA) hydrolase have been isolated from bovine lymph nodes using a novel procedure that includes besides gel filtration and ion exchange chromatography also covalent chromatography as the essential step. Both enzymes were selectively bound to the activated thiol-Sepharose and afterwards eluted with cysteine. The homogeneity of enzymes was proved by polyacrylamide gel electrophoresis

Comparisons of precipitation measurements by the Advanced Microwave Precipitation Radiometer and multiparameter radar

Includes bibliographical references.Multiparameter microwave radar measurements are based on dual-polarization and dual-frequency techniques and are well suited for microphysical inferences of complex precipitating clouds, since they depend upon the size, shape, composition, and orientation of a collection of discrete random scatterers. Passive microwave radiometer observations represent path integrated scattering and absorption phenomena of the same scatterers. The response of the upwelling brightness temperatures TB to the precipitation structure depends on the vertical distribution of the various hydrometeors and gases, and the surface features. As a result, combinations of both active and passive techniques contain great potential to markedly improve the longstanding issue of precipitation measurement from space. The NASA airborne Advanced Microwave Precipitation Radiometer (AMPR) and the National Center for Atmospheric Research (NCAR) CP-2 multiparameter radar were jointly operated during the 1991 Convection and Precipitation/Electrification experiment (CaPE) in central Florida. The AMPR is a four channel, high resolution, across-track scanning total power radiometer system using the identical multifrequency feedhorn as the widely utilized Special Sensor Microwave/Imager (SSM/I) satellite system. Surface and precipitation features are separable based on the TB behavior as a function of the AMPR channels. The radar observations are presented in a remapped format suitable for comparison with the multifrequency AMPR imagery. Striking resemblances are noted between the AMPR imagery and the radar reflectivity at successive heights, while vertical profiles of the CP-2 products along the nadir trace suggest a storm structure consistent with the viewed AMPR TB. Directly over the storm cores, the difference between the 37 and 85 GHz TB was noted to approach (and in some cases fall below) zero. Microwave radiative transfer computations show that this is theoretically possible for hail regions suspended aloft in the core of strong convective storms.This work was supported by the NASA Earth Science and Applications Division under Grant NAG8-890. The National Center for Atmospheric Research is sponsored by the National Science Foundation

Purification of Cathepsin D by Affinity Chromatography on Pepstatin Sepharose Column

A method was developed for the isolation of cathepsin D by affinity chromatography on immobilized pepstatin. This inhibitor was coupled to agarose by water soluble carbodiimide. Further purification included gel filtration on Sephadex G-100. The obtained cathepsin D exists in three active forms which were resolved on DEAE cellulose. Electrophoresis in the presence of sodium. dodecyl sulphate revealed that the first form consists of only one polypeptide chain having molecular weight 42 000. The second and the third form contain also polypeptides having molecular weight 27 000 and 14 000

Purification of Cathepsin D by Affinity Chromatography on Pepstatin Sepharose Column

A method was developed for the isolation of cathepsin D by affinity chromatography on immobilized pepstatin. This inhibitor was coupled to agarose by water soluble carbodiimide. Further purification included gel filtration on Sephadex G-100. The obtained cathepsin D exists in three active forms which were resolved on DEAE cellulose. Electrophoresis in the presence of sodium. dodecyl sulphate revealed that the first form consists of only one polypeptide chain having molecular weight 42 000. The second and the third form contain also polypeptides having molecular weight 27 000 and 14 000

Sharing the transformation: Public relations and the uae come of age

© 2009 Taylor and Francis. Much like the country itself, the practice of public relations in the United Arab Emirates (UAE) has undergone a profound evolution during its short history of 30 years. As the country has grown, so too has the practice of public relations. Once no agencies existed, but today global multinational public relations firms have established a presence in the UAE, some with an equity relationship with their local partners, some as fully owned branches of global firms based in the United States or Europe, and others through affiliates. Companies like Team: Young and Rubicam, Gulf Hill and Knowlton, and Burston-Marsteller operate alongside local, smaller companies, competing for the same dollars and dirhams

Some Properties of Thymus Cathepsin D

Cathepsin D has been purified from calf thymus using ammonium sulphate precipitation and gel chromatography on Se.phadex G-100. Preparative electrophoresis in polyacrylamide gel, used as the final step in the purification procedure, yielded four active forms of cathepsin D that dissociated further .into several polypepUde bands in the presence of sodium dodecyl sulphate. All four forms were stable over a range of pH from 4-11. They were completely inhibited by pepstatin whereas other metal ions had no appreciable effect upon their activity