A Simplified Crossing Fiber Model in Diffusion Weighted Imaging

Diffusion MRI (dMRI) is a vital source of imaging data for identifying anatomical connections in the living human brain that form the substrate for information transfer between brain regions. dMRI can thus play a central role toward our understanding of brain function. The quantitative modeling and analysis of dMRI data deduces the features of neural fibers at the voxel level, such as direction and density. The modeling methods that have been developed range from deterministic to probabilistic approaches. Currently, the Ball-and-Stick model serves as a widely implemented probabilistic approach in the tractography toolbox of the popular FSL software package and FreeSurfer/TRACULA software package. However, estimation of the features of neural fibers is complex under the scenario of two crossing neural fibers, which occurs in a sizeable proportion of voxels within the brain. A Bayesian non-linear regression is adopted, comprised of a mixture of multiple non-linear components. Such models can pose a difficult statistical estimation problem computationally. To make the approach of Ball-and-Stick model more feasible and accurate, we propose a simplified version of Ball-and-Stick model that reduces parameter space dimensionality. This simplified model is vastly more efficient in the terms of computation time required in estimating parameters pertaining to two crossing neural fibers through Bayesian simulation approaches. Moreover, the performance of this new model is comparable or better in terms of bias and estimation variance as compared to existing models

Design of Mems Based Tristate Phase Shifter Using COMSOL 4.3b

A V - band CMOS - MEMS switchable phase shifter based on reflection - type topology is presented in this work. Phase shifter is simulated by using CMOS process. Three discrete phas e states are achieved at 65GHz by using Bi - directional fishbone actuators. The measured insertion is very less and the return loss is also better than 14 dB over the 55 - 65 GHz frequency range. It demonstrates a great potential in many applications

Likelihood-based estimation of substructure content from single-wavelength anomalous diffraction (SAD) intensity data.

SAD phasing can be challenging when the signal-to-noise ratio is low. In such cases, having an accurate estimate of the substructure content can determine whether or not the substructure of anomalous scatterer positions can successfully be determined. Here, a likelihood-based target function is proposed to accurately estimate the strength of the anomalous scattering contribution directly from the measured intensities, determining a complex correlation parameter relating the Bijvoet mates as a function of resolution. This gives a novel measure of the intrinsic anomalous signal. The SAD likelihood target function also accounts for correlated errors in the measurement of intensities from Bijvoet mates, which can arise from the effects of radiation damage. When the anomalous signal is assumed to come primarily from a substructure comprising one anomalous scatterer with a known value of f'' and when the protein composition of the crystal is estimated correctly, the refined complex correlation parameters can be interpreted in terms of the atomic content of the primary anomalous scatterer before the substructure is known. The maximum-likelihood estimation of substructure content was tested on a curated database of 357 SAD cases with useful anomalous signal. The prior estimates of substructure content are highly correlated to the content determined by phasing calculations, with a correlation coefficient (on a log-log basis) of 0.72

Halo phenomenon in finite many-fermion systems. Atom-positron complexes and large-scale study of atomic nuclei

The analysis method proposed in Ref. \cite{rotival07a} is applied to characterize halo properties in finite many-fermion systems. First, the versatility of the method is highlighted by applying it to light and medium-mass nuclei as well as to atom-positron and ion-positronium complexes. Second, the dependence of nuclear halo properties on the characteristics of the energy density functional used in self-consistent Hartree-Fock-Bogoliubov calculations is studied. It is found that (a) the low-density behavior of the pairing functional and the regularization/renormalization scheme must be chosen coherently and with care to provide meaningful predictions, (b) the impact of pairing correlations on halo properties is significant and is the result of two competing effects, (c) the detailed characteristics of the pairing functional has however only little importance, (d) halo properties depend significantly on any ingredient of the energy density functional that influences the location of single-particle levels; i.e. the effective mass, the tensor terms and the saturation density of nuclear matter. The latter dependencies give insights to how experimental data on medium-mass drip-line nuclei can be used in the distant future to constrain some characteristics of the nuclear energy density functional. Last but not least, large scale predictions of halos among all spherical even-even nuclei are performed using specific sets of particle-hole and particle-particle energy functionals. It is shown that halos in the ground state of medium-mass nuclei will only be found at the very limit of neutron stability and for a limited number of elements.Comment: 24 Pages, 32 Figures. Accepted for publication in Phys. Rev. C back-to back with first part (nucl-th/0702050

Response of preservative chemicals on the shelf life of cut lilium (Lilium spp.) flower cv. ‘Pavia’

Lilium cut flowers have commercial importance and extending their vase life is vital. An increase in the vase life quality and quantity can directly increase the viability and price realization of commercially important flowers like lilium. Shelf life of cut lilium flower is influenced by using different preservative chemicals and sucrose added in vase solution. Such an extension of vase life can be achieved via chemical treatment. The trial was carried out to examine the effect of various concentration of two chemicals, AgNO3 (silver nitrate) and 8-HQC (8-Hydroxyquinoline citrate) along with sucrose on the shelf life of lilium cut flower cv. ‘Pavia’ (cross between Asiatic and Longiflorum lilies). In the experiment, sucrose (20%), 8-HQC at 3 concentrations (100, 150, 200 ppm) and AgNO3 at 3 concentrations (50, 75, 100 ppm) and water (distilled) as control were tested alone and with combinations. Cut flowers of lilium were treated at one bud opening stage. The trial was carried out in a completely randomized design (CRD) having 16 treatments and one control in three (3) replications. The fresh weight and relative fresh weight of the cut flower spike, opening of all flowers on a spike, vase solution uptake on a day, total vase solution uptake and vase life of lilium cut flower spike showed the best outcome with AgNO3 (50 ppm) and 20% sucrose treatment combination. Out of the two chemicals, silver nitrate showed better results than 8-HQC as a preservative in enhancing the shelf life of cut Lilium flower cv. ‘Pavia’. Analysis of this new and exciting method will be useful to research institutes, commercial producers, wholesalers, retailers, consumers or anyone to choose right chemical and concentration of holding solution to maximize the post-harvest life of lilium cut flowers

Digestibility of extruded peas, extruded lupin, and rapeseed meal in rainbow trout (Oncorhynchus mykiss) and turbot (Psetta maxima)

Apparent digestibility coefficients (ADC) of nutrients and energy of extruded peas, extruded lupin and rapeseed meals were determined in juvenile rainbow trout and turbot. Extruded lupin was found to be a promising substitute for fish meal in the diets of trout and turbot, with an acceptable digestibility of its dry matter (70% in trout and 81% in turbot) and a high digestibility of its protein (96% in trout and 98% in turbot) and its energy (77% in trout and 85% in turbot). Extruded peas had a lower digestibility of its protein in trout (88%) than in turbot (92%), and the ADC of energy, mainly supplied as starch, was relatively low (69% in trout and 78% in turbot). The digestibility of rapeseed meal was improved by a thermal treatment. Without thermal treatment, rapeseed meal had a low digestibility of its dry matter (57%) and energy (69%) in turbot. The availability of phosphorus was higher for extruded lupin (62% in trout and 100% in turbot) compared to the other plant-ingredients. When compared to a solvent-extracted meal, the availability of phosphorus from rapeseed meal was improved by heat treatment in both species (42% vs. 26% in trout and 65% vs. 49% in turbot). (C) 2000 Elsevier Science B.V

A study on the effect of silver nitrate and 8-hydroxyquinoline citrate pulsing solutions on Lilium cut flowers

Lilium is one of the most important cut flowers in commercial markets, giving customers ornamental value. Fresh flowers, a highly perishable item, need more care and proper treatment for their longer post-harvest life and due to this, the end users face the post-harvest losses of cut flowers. Such losses can be minimized by using preservative chemical, which plays an important role in increasing the vase life of flowers. To increase the post-harvest life of lilium cut flowers cv. ‘Pavia’, the present investigation was aimed to study the effect of different combinations and concentrations of silver nitrate at 50, 75 and 100 ppm and 8-hydroquinoline citrate at 100, 150 and 200 ppm pulsing solutions with 20 % sucrose. Three replications were completely randomised with 16 treatments and one control. Silver nitrate showed better results in flower bud opening, flower bud opening to complete flowering, flower size, bloom life, dry weight and dry matter percentage. Among the treatment concentrations, AgNO3 at 50 ppm with 20% sucrose showed the most effective result on enhancing the selected parameters and improved flower quality during post-harvest life. Among the treatment combinations, 8-HQC at 100 ppm + AgNO3 at 75 ppm with 20 % sucrose showed better results. These findings will be useful to researchers, farmers, and end users to retain the ornamental value of lilium cut flowers for longer than usual