The discrete rotational Fourier transform

We define a discrete version of the angular Fourier transform and present the properties of the transform that show it to be a rotation in time-frequency space, this new transform is a generalization of the DFT. Efficient algorithms for its computation can then be based on the FFT and the eigenstructure of the DFT     

Tandem mass spectrometric determination of the 4S/6S sulfation sequence in chondroitin sulfate oligosaccharides.

Chondroitin sulfate (CS) is a glycosaminoglycan consisting of repeating uronic acid, N-acetylgalactosamine sulfate disaccharide units [-UroA(beta1,3)-GalNAcS(beta1,4)]n. Chondroitin sulfate type A (CSA) contains glucuronic acid, and 90% of the GalNAc residues are sulfated at the 4-position with 10% at the 6-position. Chondroitin sulfate type C (CSC) contains glucuronic acid, and 90% of the GalNAc residues are sulfated at the 6-position with 10% sulfated at the 4-position. These molecules are fragile due to their high degree of sulfation and are challenging to analyze as a result. This work presents the first evidence that tandem mass spectrometry can be used for the determination of a CS oligosaccharide sequence with respect to the positions of GalNAc sulfation. Using this technique, it is possible to analyze individual components from mixtures, saving much purification effort. Oligosaccharides produced from CSA and CSC are used in this work to demonstrate that CID MS/MS can be used to distinguish positional sulfation isomers. For charge states where charge equals the number of sulfates, abundant odd-numbered Bn and Yn ions are observed. The percent total ion abundances of these ions indicate the position of sulfation.     

Low computation and low latency algorithms for distributed sensor network initialization

In this paper, we show how an underlying system’s state vector distribution can be determined in a distributed heterogeneous sensor network with reduced subspace observability at the individual nodes. The presented algorithm can generate the initial state vector distribution for networks with a variety of sensor types as long as the collective set of measurements from all the sensors provides full state observability. Hence the network, as a whole, can be capable of observing the target state vector even if the individual nodes are not capable of observing it locally. Initialization is accomplished through a novel distributed implementation of the particle filter that involves serial particle proposal and weighting strategies that can be accomplished without sharing raw data between individual nodes. If multiple events of interest occur, their individual states can be initialized simultaneously without requiring explicit data association across nodes. The resulting distributions can be used to initialize a variety of distributed joint tracking algorithms. We present two variants of our initialization algorithm: a low complexity implementation and a low latency implementation. To demonstrate the effectiveness of our algorithms we provide simulation results for initializing the states of multiple maneuvering targets in smart sensor networks consisting of acoustic and radar sensors. Prepared through collaborative participation in the Advanced Sensors Consortium sponsored by the US Army Research Laboratory under the Collaborative Technology Alliance Program, Cooperative Agreement DAAD19-01-02-0008.     

Symbolic convolution

An implementation of convolution using a symbolic mathematics software package is described. The emphasis is on the internal data structure needed to represent signals that are defined piecewise over disjoint intervals. Then the overlap-add form of convolution is used to produce the convolution of signals that are the sum of piecewise segments. A working implementation has been completed for both discrete-time and continous-time convolution. Several examples are shown to illustrate the results and to suggest ways in which this sort of software might be useful for classroom presentations     

Levobupivacaine

Levobupivacaine is an enantiomer of the long-acting local anaesthetic bupivacaine, which, although currently the most widely used agent in surgery and obstetrics, is associated with potentially fatal cardiotoxicity. Levobupivacaine 75 to 122 mg was less arrhythmogenic than the same dose range of bupivacaine in healthy volunteers. Its effects on the corrected QT interval were significantly weaker than those of bupivacaine, and it tended to have a weaker effect on QRS duration. The CNS depressant effect of intravenous levobupivacaine 40 mg was less than that of bupivacaine 40 mg in healthy volunteers, both in terms of the magnitude of the effect and the regions of the cortex affected. Clinical studies have demonstrated that epidural levobupivacaine produces a sensory and motor block clinically similar to that of bupivacaine in patients requiring anaesthesia during surgery. However, the duration of sensory block was significantly longer with levobupivacaine 0.75% than with levobupivacaine 0.5% or bupivacaine 0.5% or 0.75% in one study. Levobupivacaine 0.25% was as effective as bupivacaine 0.25% in women requiring epidural anaesthesia during labour with respect to time to onset of pain relief, overall quality of analgesia, extent of sensory blockade and number of patients reporting motor block. Levobupivacaine is as well tolerated as bupivacaine. In a clinical study involving 88 patients who received either drug, intraoperative hypotension was the most commonly reported adverse event with levobupivacaine and no serious arrhythmias occurred.     

Teach-Ware: DSP education resources

This paper describes a variety of TeachWare, i.e., digital signal processing (DSP) education resources that are useful for introducing DSP concepts, operations, and algorithms. The paper provides such information as the type of resource, its status, and format.     

Effect of amounts and sequence of additions of urea and water on hydrolysis of surface-applied granular urea in unsaturated soils

The hydrolysis of surface-applied granular urea ( 15 mg of urea/particle) in 14 unsaturated soils as influenced by the amounts and the sequence of additions of urea and water and studied using open and covered soil column systems was in the following order: well-mixed surface-applied surface-applied surface-applied urea, granular urea, granular urea, granular urea, water added > water added > water added water added before, after, before, before, no drying no drying no drying drying The retarded hydrolysis' of surface-applied granular urea is attributed to retarded soil urease activity. Under the nondrying and drying conditions, the positive effect of increasing amounts of added water on the hydrolysis was less apparent when water was added 24–48 hours before than when it was added immediately after surface application of granular urea. When an increasing number of urea granules were evenly placed on a finite surface of unsaturated soil, the rate of urea application (quantity factor) increased but the percentage of urea hydrolyzed remained practically unchanged. These results suggest that it is necessary to consider effective urea concentration and effective urease activity for adequate understanding of in situ hydrolysis of broadcast fertilizer urea in unsaturated soil.