A survey of parallel algorithms for fractal image compression

This paper presents a short survey of the key research work that has been undertaken in the application of parallel algorithms for Fractal image compression. The interest in fractal image compression techniques stems from their ability to achieve high compression ratios whilst maintaining a very high quality in the reconstructed image. The main drawback of this compression method is the very high computational cost that is associated with the encoding phase. Consequently, there has been significant interest in exploiting parallel computing architectures in order to speed up this phase, whilst still maintaining the advantageous features of the approach. This paper presents a brief introduction to fractal image compression, including the iterated function system theory upon which it is based, and then reviews the different techniques that have been, and can be, applied in order to parallelize the compression algorithm

Testing T Invariance in the Interaction of Slow Neutrons with Aligned Nuclei

The study of five-fold (P even, T odd) correlation in the interaction of slow polarized neutrons with aligned nuclei is a possible way of testing the time reversal invariance due to the expected enhancement of T violating effects in compound resonances. Possible nuclear targets are discussed which can be aligned both dynamically as well as by the "brute force" method at low temperature. A statistical estimation is performed of the five-fold correlation for low lying p wave compound resonances of the $^{121}$Sb, $^{123}$Sb and $^{127}$I nuclei. It is shown that a significant improvement can be achieved for the bound on the intensity of the fundamental parity conserving time violating (PCTV) interaction.Comment: 22 pages, 5 figures, published versio

Quantum Capacity Approaching Codes for the Detected-Jump Channel

The quantum channel capacity gives the ultimate limit for the rate at which quantum data can be reliably transmitted through a noisy quantum channel. Degradable quantum channels are among the few channels whose quantum capacities are known. Given the quantum capacity of a degradable channel, it remains challenging to find a practical coding scheme which approaches capacity. Here we discuss code designs for the detected-jump channel, a degradable channel with practical relevance describing the physics of spontaneous decay of atoms with detected photon emission. We show that this channel can be used to simulate a binary classical channel with both erasures and bit-flips. The capacity of the simulated classical channel gives a lower bound on the quantum capacity of the detected-jump channel. When the jump probability is small, it almost equals the quantum capacity. Hence using a classical capacity approaching code for the simulated classical channel yields a quantum code which approaches the quantum capacity of the detected-jump channel

High efficiency thermionic converter studies

Research in thermionic energy conversion technology is reported. The objectives were to produce converters suitable for use in out of core space reactors, radioisotope generators, and solar satellites. The development of emitter electrodes that operate at low cesium pressure, stable low work function collector electrodes, and more efficient means of space charge neutralization were investigated to improve thermionic converter performance. Potential improvements in collector properties were noted with evaporated thin film barium oxide coatings. Experiments with cesium carbonate suggest this substance may provide optimum combinations of cesium and oxygen for thermionic conversion

Fundamental constraints on particle tracking with optical tweezers

A general quantum limit to the sensitivity of particle position measurements is derived following the simple principle of the Heisenberg microscope. The value of this limit is calculated for particles in the Rayleigh and Mie scattering regimes, and with parameters which are relevant to optical tweezers experiments. The minimum power required to observe the zero-point motion of a levitating bead is also calculated, with the optimal particle diameter always smaller than the wavelength. We show that recent optical tweezers experiments are within two orders of magnitude of quantum limited sensitivity, suggesting that quantum optical resources may soon play an important role in high sensitivity tracking applications

A Single Antibody based ELISA for the N-terminal sequence of BAG-75, a New Biomarker for Bone Formation [abstract]

Biomedical Tissue Engineering, Biomaterials, & Medical Devices Poster SessionBone acidic glycoprotein-75 (BAG-75) is a secreted product of osteoblastic cells localized predominantly to areas of new bone formation. We have identified the N-terminal sequence of BAG-75 as LPVARYQNTEEEE and shown that anti-peptide antibodies against residues #3-13 only recognize the 75 kDa precursor and apparent 50 kDa fragment in serum and in osteoblastic cultures. Formation of the 50 kDa fragment is blocked by AEBSF, a serine protease inhibitor which we also showed blocks mineralization in osteoblastic cultures. Measurement of BAG-75 and its fragment concentration in serum represents a new method to estimate the rate of new bone formation in vivo. Our purpose was to establish an anti-VARYQNTEEEE peptide antibody based ELISA test to measure cross-reactive proteins released from bone into blood. Western blotting was performed using young rat serum from different ages, rats subjected to ovariectomy (OVX) or sham surgery, and normal human serum. Immunoreactive 50 kDa fragment peaked at 18 days after birth which parallels bone formation. Ovariectomized rats displayed a peak of 50 kDa immunoreactivty at 21 days after surgery which corresponds to a spike in bone formation in this model (~2.5-fold above controls). Comparable assays for osteocalcin showed only a 39% increase. Also, human serum contains a 50 kDa protein which cross-reacts with anti-VARYQNTEEEE antibodies. We then established a competitive 96-well ELISA using anti-peptide antibody and new sera at 21 days from ovariectomized or sham rats, a model for stimulated bone formation. VARYQNTEEEE peptide conjugated to keyhole limpet hemocyanin (KLH) was used as the bound antigen. KLH-peptide amount, primary antibody concentration, secondary antibody concentration, and blocking agent were optimized in a series of experiments. Optimal conditions were determined to be 2 µg input KLH-peptide per well, 1/5,000 dilution of primary anti-VARYQNTEEEE antibody, 1/10,000 dilution of secondary antibody, and gelatin as a blocking agent. Sera from OVX rats and sham-operated controls were compared to the standard curve (r = 0.9923) created with free KLH-peptide as competitor to determine the equivalent amount of KLH-peptide present. OVX sera (n=3) contained an average 2.6 x 10-4 (+/- 1.4 x 10-4) µg peptide equivalent versus 1.05 x 10-4 (+/- 0.68 x 10-4) µg for sham sera (n=3). The difference was not significant (t-test, p=0.157), however, doubling the sample size is predicted to yield significance. Conclusions: A. Cross-reactive 75 kDa and 50 kDa proteins are present in human and rat serum and increase in concentration when bone formation is stimulated. B. A new, single antibody based ELISA assay was established to quantitate antigen released from bone into blood. C. In contrast to other commercial bone formation assays (collagen peptides and osteocalcin), the size of cross-reactive protein (>50 kDa) should preclude kidney filtration and facilitate measurement. D. This serum biomarker undergoes a 2-3 fold average increase within 3 weeks after simulation of bone. This test may be useful to monitor the early response to stimulatory therapy in osteoporosis patients or to repressive glucocorticoid therapy in sarcoidosis patients. Currently, a 1% change in bone mineral density requires 12-18 months to detect by x-ray methods

Salen Mn Complexes Mitigate Radiation Injury in Normal Tissues

Salen Mn complexes, including EUK-134, EUK-189 and a newer cyclized analog EUK-207, are synthetic SOD/catalase mimetics that have beneficial effects in many models of oxidative stress. As oxidative stress is implicated in some forms of delayed radiation injury, we are investigating whether these compounds can mitigate injury to normal tissues caused by ionizing radiation. This review describes some of this research, focusing on several tissues of therapeutic interest, namely kidney, lung, skin, and oral mucosa. These studies have demonstrated suppression of delayed radiation injury in animals treated with EUK-189 and/or EUK-207. While an antioxidant mechanism of action is postulated, it is likely that the mechanisms of radiation mitigation by these compounds in vivo are complex and may differ in the various target tissues. Indicators of oxidative stress are increased in lung and skin radiation injury models, and suppressed by salen Mn complexes. The role of oxidative stress in the renal injury model is unclear, though EUK-207 does mitigate. In certain experimental models, salen Mn complexes have shown “mito-protective” properties, that is, attenuating mitochondrial injury. Consistent with this, EUK-134 suppresses effects of ionizing radiation on mitochondrial function in rat astrocyte cultures. In summary, salen Mn complexes could be useful to mitigate delayed radiation injury to normal tissues following radiation therapy, accidental exposure, or radiological terrorism. Optimization of their mode of delivery and other key pharmaceutical properties, and increasing understanding of their mechanism(s) of action as radiation mitigators, are key issues for future study