Efficient binary phase quantizer based on phase sensitive four wave mixing

We experimentally demonstrate an efficient binary phase quantizer operating at low pump powers. Phase-sensitive operation is obtained by polarization mixing the phase-locked signal/idler pair in a degenerate dual-pump vector parametric amplifier

Quadrature decomposition of optical fields using two orthogonal phase sensitive amplifiers

We propose a new technique to optically process coherent signals by simultaneously extracting their two (I and Q) quadrature components into two orthogonal polarizations at the same frequency. Two possible implementations are demonstrated

Evaluation of algorithms for estimating wheat acreage from multispectral scanner data

The author has identified the following significant results. Fourteen different classification algorithms were tested for their ability to estimate the proportion of wheat in an area. For some algorithms, accuracy of classification in field centers was observed. The data base consisted of ground truth and LANDSAT data from 55 sections (1 x 1 mile) from five LACIE intensive test sites in Kansas and Texas. Signatures obtained from training fields selected at random from the ground truth were generally representative of the data distribution patterns. LIMMIX, an algorithm that chooses a pure signature when the data point is close enough to a signature mean and otherwise chooses the best mixture of a pair of signatures, reduced the average absolute error to 6.1% and the bias to 1.0%. QRULE run with a null test achieved a similar reduction

Carnivore damage to antelope bones and its archaeological implications

Main articleThe rates of survival, damage, fragmentation and degree of articulation of the bones of 89 bovids eaten by a variety of carnivores in the Transvaal are presented and evaluated. These results are entirely predictable considering the size, density, shape and mode of attachment of the bones. With the exception of the brown and spotted hyaenas the extent of damage to these bones can be directly related to the sizes of the bovids and the carnivores concerned. The hyaenas have disproportionately high abilities to crush bones, particularly the long limb bones. The bones all had fairly uniform survival rates except the ribs, carpals, tarsals, phalanges and caudal vertebrae, which are easily eaten or removed. Mandibles and scapulae had exceptionally low articulation rates, and long bones, crania and ribs had the highest fragmentation rates. Small bovid bones were far more susceptible to damage by trampling than those of larger bovids. Certain differences between carnivore and hominid damage to bones are mentioned. These relate primarily to hominids using their hands to dismember and damage bones selectively, particularly long bones which are broken in half to extract the marrow. A different pattern of survival of long bone epiphyses resulting from hominid activity can be predicted from that caused by carnivores, especially hyaenas. The pattern of survival of epiphyses at Makapansgat is that predicted for hominids, whereas the pattern at Swartklip I, an accepted hyaena site, is the opposite. It is therefore suggested that australopithecines were the primary bone collectors at Makapansgat. Further data on the differences between carnivore and hominid damage are also presented.Non

Methods of editing cloud and atmospheric layer affected pixels from satellite data

Subvisible cirrus clouds (SCi) were easily distinguished in mid-infrared (MIR) TIROS-N daytime data from south Texas and northeast Mexico. The MIR (3.55-3.93 micrometer) pixel digital count means of the SCi affected areas were more than 3.5 standard deviations on the cold side of the scene means. (These standard deviations were made free of the effects of unusual instrument error by factoring out the Ch 3 MIR noise on the basis of detailed examination of noisy and noise-free pixels). SCi affected areas in the IR Ch 4 (10.5-11.5 micrometer) appeared cooler than the general scene, but were not as prominent as in Ch 3, being less than 2 standard deviations from the scene mean. Ch 3 and 4 standard deviations and coefficients of variation are not reliable indicators, by themselves, of the presence of SCi because land features can have similar statistical properties

The Extraordinarily Rapid Expansion of the X-ray Remnant of Kepler's Supernova (SN1604)

Four individual high resolution X-ray images from ROSAT and the Einstein Observatory have been used to measure the expansion rate of the remnant of Kepler's supernova (SN 1604). Highly significant measurements of the expansion have been made for time baselines varying from 5.5 yrs to 17.5 yrs. All measurements are consistent with a current expansion rate averaged over the entire remnant of 0.239 (+/-0.015) (+0.017,-0.010) % per yr, which, when combined with the known age of the remnant, determines the expansion parameter m, defined as $R\propto t^m$, to be 0.93 (+/-0.06) (+0.07,-0.04). The error bars on these results include both statistical (first set of errors) and systematic (second set) uncertainty. According to this result the X-ray remnant is expanding at a rate that is remarkably close to free expansion and nearly twice as fast as the mean expansion rate of the radio remnant. The expansion rates as a function of radius and azimuthal angle are also presented based on two ROSAT images that were registered to an accuracy better than 0.5 arcseconds. Significant radial and azimuthal variations that appear to arise from the motion of individual X-ray knots are seen. The high expansion rate of the X-ray remnant appears to be inconsistent with currently accepted dynamical models for the evolution of Kepler's SNR.Comment: 14 pages, including 7 postscript figs, LaTeX, emulateapj. Accepted by Ap

Novel polarization-assisted phase sensitive optical signal processor requiring low nonlinear phase shifts

We demonstrate a new scheme to achieve binary step-like phase response and high phase-sensitive extinction ratio at low powers. Phase-sensitive operation is achieved by polarization filtering phase-locked signal/idler in a degenerate dual-pump vector parametric amplifier

Phase sensitive amplifiers for regeneration of phase encoded optical signal formats

We discuss the application of phase sensitive fiber optical parametric devices for the regenerative processing of high baud rate optical signals. We present recent advances in phase-sensitive amplification technology and its application to the regeneration of phase-encoded signals. By combining four wave mixing based parametric effects in highly nonlinear optical fibers and injection locking assisted synchronisation of multiple coherent lasers, we demonstrate how it possible to derive phase regeneration in signals with more than two levels of phase encoding

Design-for-test structure to facilitate test vector application with low performance loss in non-test mode.

A switching based circuit is described which allows application of voltage test vectors to internal nodes of a chip without the problem of backdriving. The new circuit has low impact on the performance of an analogue circuit in terms of loss of bandwidth and allows simple application of analogue test voltages into internal nodes. The circuit described facilitates implementation of the forthcoming IEEE 1149.4 DfT philosophy [1]

Stereociliary Myosin-1c Receptors Are Sensitive to Calcium Chelation and Absent from Cadherin 23 Mutant Mice

The identities of some of the constituents of the hair-cell transduction apparatus have been elucidated only recently. The molecular motor myosin-1c (Myo1c) functions in adaptation of the hair-cell response to sustained mechanical stimuli and is therefore an integral part of the transduction complex. Recent data indicate that Myo1c interacts in vitro with two other molecules proposed to be important for transduction: cadherin 23 (Cdh23), a candidate for the stereociliary tip link, and phosphatidylinositol 4,5-bisphosphate (PIP2), which is abundant in the membranes of hair-cell stereocilia. It is not known, however, whether these interactions occur in hair cells. Using an in situ binding assay on saccular hair cells, we demonstrated previously that Myo1c interacts with molecules at stereociliary tips, the site of transduction, through sequences contained within its calmodulin (CaM)-binding neck domain, which can bind up to four CaM molecules. In the current study, we identify the second CaM-binding IQ domain as a region of Myo1c that mediates CaM-sensitive binding to stereociliary tips and to PIP2 immobilized on a solid support. Binding of Myo1c to stereociliary tips of cochlear and vestibular hair cells is disrupted by treatments that break tip links. In addition, Myo1c does not bind to stereocilia from mice whose hair cells lack Cdh23 protein despite the presence of PIP2 in the stereociliary membranes. Collectively, our data suggest that Myo1c and Cdh23 interact at the tips of hair-cell stereocilia and that this interaction is modulated by CaM