25,420 research outputs found
() spectroscopy using Cornell potential
The mass spectra and decay properties of heavy quarkonia are computed in
nonrelativistic quark-antiquark Cornell potential model. We have employed the
numerical solution of Schr\"odinger equation to obtain their mass spectra using
only four parameters namely quark mass (, ) and confinement strength
(, ). The spin hyperfine, spin-orbit and tensor
components of the one gluon exchange interaction are computed perturbatively to
determine the mass spectra of excited , , and states. Digamma,
digluon and dilepton decays of these mesons are computed using the model
parameters and numerical wave functions. The predicted spectroscopy and decay
properties for quarkonia are found to be consistent with available experimental
observations and results from other theoretical models. We also compute mass
spectra and life time of the meson without additional parameters. The
computed electromagnetic transition widths of heavy quarkonia and mesons
are in tune with available experimental data and other theoretical approaches
Simulation of Thematic Mapper performance as a function of sensor scanning parameters
The investigation and results of the Thematic Mapper Instrument Performance Study are described. The Thematic Mapper is the advanced multispectral scanner initially planned for the Earth Observation Satellite and now planned for LANDSAT D. The use of existing digital airborne scanner data obtained with the Modular Multispectral Scanner (M2S) at Bendix provided an opportunity to simulate the effects of variation of design parameters of the Thematic Mapper. Analysis and processing of this data on the Bendix Multispectral Data Analysis System were used to empirically determine categorization performance on data generated with variations of the sampling period and scan overlap parameters of the Thematic Mapper. The Bendix M2S data, with a 2.5 milliradian instantaneous field of view and a spatial resolution (pixel size) of 10-m from 13,000 ft altitude, allowed a direct simulation of Thematic Mapper data with a 30-m resolution. The flight data chosen were obtained on 30 June 1973 over agricultural test sites in Indiana
A technique for correcting ERTS data for solar and atmospheric effects
The author has identified the following significant results. Based on processing ERTS CCTs and ground truth measurements collected on Michigan test site for January through June 1973 the following results are reported: (1) atmospheric transmittance varies from: 70 to 85% in band 4, 77 to 90% in band 5, 80 to 94% in band 6, and 84 to 97% in band 7 for one air mass; (2) a simple technique was established to determine atmospheric scattering seen by ERTS-1 from ground-based measurements of sky radiance. For March this scattering was found to be equivalent to that produced by a target having a reflectance of 11% in band 4, 5% in band 5, 3% in band 6, and 1% in band 7; (3) computer ability to classify targets under various atmospheric conditions was determined. Classification accuracy on some targets (i.e. bare soil, tended grass, etc.) hold up even under the most severe atmospheres encountered, while performance on other targets (trees, urban, rangeland, etc.) degrades rapidly when atmospheric conditions change by the smallest amount
Dietary elimination of children with food protein induced gastrointestinal allergy – micronutrient adequacy with and without a hypoallergenic formula?
Background:
The cornerstone for management of Food protein-induced gastrointestinal allergy (FPGIA) is dietary exclusion; however the micronutrient intake of this population has been poorly studied. We set out to determine the dietary intake of children on an elimination diet for this food allergy and hypothesised that the type of elimination diet and the presence of a hypoallergenic formula (HF) significantly impacts on micronutrient intake.
Method:
A prospective observational study was conducted on children diagnosed with FPIGA on an exclusion diet who completed a 3 day semi-quantitative food diary 4 weeks after commencing the diet. Nutritional intake where HF was used was compared to those without HF, with or without a vitamin and mineral supplement (VMS).
Results:
One-hundred-and-five food diaries were included in the data analysis: 70 boys (66.7%) with median age of 21.8 months [IQR: 10 - 67.7]. Fifty-three children (50.5%) consumed a HF and the volume of consumption was correlated to micronutrient intake. Significantly (p <0.05) more children reached their micronutrient requirements if a HF was consumed. In those without a HF, some continued not to achieve requirements in particular for vitamin D and zinc, in spite of VMS.
Conclusion:
This study points towards the important micronutrient contribution of a HF in children with FPIGA. Children, who are not on a HF and without a VMS, are at increased risk of low intakes in particular vitamin D and zinc. Further studies need to be performed, to assess whether dietary intake translates into actual biological deficiencies
Explaining Snapshots of Network Diffusions: Structural and Hardness Results
Much research has been done on studying the diffusion of ideas or
technologies on social networks including the \textit{Influence Maximization}
problem and many of its variations. Here, we investigate a type of inverse
problem. Given a snapshot of the diffusion process, we seek to understand if
the snapshot is feasible for a given dynamic, i.e., whether there is a limited
number of nodes whose initial adoption can result in the snapshot in finite
time. While similar questions have been considered for epidemic dynamics, here,
we consider this problem for variations of the deterministic Linear Threshold
Model, which is more appropriate for modeling strategic agents. Specifically,
we consider both sequential and simultaneous dynamics when deactivations are
allowed and when they are not. Even though we show hardness results for all
variations we consider, we show that the case of sequential dynamics with
deactivations allowed is significantly harder than all others. In contrast,
sequential dynamics make the problem trivial on cliques even though it's
complexity for simultaneous dynamics is unknown. We complement our hardness
results with structural insights that can help better understand diffusions of
social networks under various dynamics.Comment: 14 pages, 3 figure
Novel approaches in development of cell penetrating peptides
Therapeutic cargos which are impermeable to the cell can be delivered by cell penetrating peptides (CPPs). CPP-cargo complexes accumulate by endocytosis inside the cells but they fail to reach the cytosolic space properly as they are often trapped in the endocytic organelles. Here the CPP mediated endosomal escape and some strategies used to increase endosomal escape of CPP-cargo conjugates are discussed with evidence. Potential benefits can be obtained by peptides such as reduction in side effects, biocompatibility, easier synthesis and can be obtained at lower administered doses. The particular peptide known as cell penetrating peptides are able to translocate themselves across membrane with the carrier drugs with different mechanisms. This is of prime importance in drug delivery systems as they have capability to cross physiological membranes. This review describes various mechanisms for effective drug delivery and associated challenge
Study of the technique of stellar occultation
The results are reported of a study of the stellar occultation technique for measuring the composition of the atmosphere. The intensity of starlight was monitored during the occultation using the Wisconsin stellar ultraviolet photometers aboard the Orbiting Astronomical Observatory (OAO-A2). A schematic diagram of an occultation is shown where the change in intensity at a given wavelength is illustrated. The vertical projection of the attenuation region is typically 60 km deep for molecular oxygen and 30 km deep for ozone. Intensity profiles obtained during various occultations were analyzed by first determining the tangential columm density of the absorbing gases, and then Abel inverting the column densities to obtain the number density profile. Errors are associated with each step in the inversion scheme and have been considered as an integral part of this study
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