Realization and Characterization of a Four-Channel Integrated Optical Young Interferometer

In this paper, we report the realization and characterization of a four-channel integrated optical Young interferometer (YI), which enables simultaneous and independent monitoring of three binding processes. The simultaneous and independent measurement of three different glucose concentrations shows the multi-purpose feature of such device. The phase resolution for different pairs of channels was /spl sim/1/spl times/10/sup -4/ fringes, which corresponds to a refractive index resolution of /spl sim/8.5/spl times/10/sup -8/ . The observed errors, which are caused due to mismatching of spatial frequencies of individual interference patterns with those determined from the CCD camera, have been reduced by using different reduction schemes. In addition, we have investigated a novel method for discrimination of the refractive index change from the thickness of a bound layer during an immunoreaction, as well as measuring the temperature change the takes place during such a process

Changes in wave climate over the northwest European shelf seas during the last 12,000 years

Because of the depth attenuation of wave orbital velocity, wave-induced bed shear stress is much more sensitive to changes in total water depth than tidal-induced bed shear stress. The ratio between wave- and tidal-induced bed shear stress in many shelf sea regions has varied considerably over the recent geological past because of combined eustatic changes in sea level and isostatic adjustment. In order to capture the high-frequency nature of wind events, a two-dimensional spectral wave model is here applied at high temporal resolution to time slices from 12 ka BP to present using paleobathymetries of the NW European shelf seas. By contrasting paleowave climates and bed shear stress distributions with present-day conditions, the model results demonstrate that, in regions of the shelf seas that remained wet continuously over the last 12,000 years, annual root-mean-square (rms) and peak wave heights increased from 12 ka BP to present. This increase in wave height was accompanied by a large reduction in the annual rms wave- induced bed shear stress, primarily caused by a reduction in the magnitude of wave orbital velocity penetrating to the bed for increasing relative sea level. In regions of the shelf seas which remained wet over the last 12,000 years, the annual mean ratio of wave- to (M-2) tidal-induced bed shear stress decreased from 1 (at 12 ka BP) to its present-day value of 0.5. Therefore compared to present- day conditions, waves had a more important contribution to large-scale sediment transport processes in the Celtic Sea and the northwestern North Sea at 12 ka BP

Tolerance and application of polarization independent waveguide for communication devices

A polarization independent optical waveguide structure has been developed and optimized towards minimized dependence on deviations in the processing parameters and very low processing complexity. The tolerance analysis was based on typical parameters of the silicon oxynitride technology. The optimized waveguide structure meets the criterion of a channel birefringence within 5x10-5 taking the processing tolerance into account. Moreover, it was found that the channel birefringence is thickness independent (within the 10-5 criterion) over a range of up to 200 nm. The optimized waveguide, fulfilling also the remaining demands of the application, has been applied for the realization of a passband flattened add-drop multiplexing device with 0.4 nm free spectral range and 0.03 nm TE-TM shift

The geomorphological setting of some of Scotland's east coast freshwater mills: a comment on Downward and Skinner (2005) ‘Working rivers: the geomorphological legacy...’

Many of the water mills on Scotland's east coast streams, unlike those discussed recently by Downward and Skinner (2005 Area 37 138–47), are found in predominantly bedrock reaches immediately downstream of knickpoints (i.e. bedrock steps). Bedrock knickpoints in the lower reaches of Scottish rivers are a widespread fluvial response to the glacio-isostatic rebound of northern Britain. These steps in the river profile propagate headward over time, but for intervals of a few centuries or so they are sufficiently stable to be exploited for the elevational fall necessary to power the mill wheel. Many of these mills were apparently powered by ‘run-of-the-river’, as are some today that formerly had mill dams. The typical lack of sediment storage along the erosional lower reaches of many Scottish rivers means that failure of mill structures in Scotland will probably have less dramatic geomorphological and management implications than those suggested by Downward and Skinner for southern English rivers

Design and realisation of a MZI type polymer based high speed EO-modulator

We designed a 20 GHz Mach Zehnder interferometric EO-modulator based on a new developed polyesterimide. Measurements show a V/sub /spl pi// of 7.5 V, an insertion loss of 11 dB and an extinction ratio exceeding 20 dB for an interaction length of 2 cm

Detection of Phase Jumps of Free Core Nutation of the Earth and their Concurrence with Geomagnetic Jerks

We detected phase jumps of the Free Core Nutation (FCN) of the Earth directly from the analysis of the Very Long Baseline Interferometer (VLBI) observation of the Earth rotation for the period 1984-2003 by applying the Weighted Wavelet Z-Transform (WWZ) method and the Short-time Periodogram with the Gabor function (SPG) method. During the period, the FCN had two significant phase jumps in 1992 and 1998. These epochs coincide with the reported occurrence of geomagnetic jerks.Comment: 8 pages, 4 figure

Tidal torques. A critical review of some techniques

We point out that the MacDonald formula for body-tide torques is valid only in the zeroth order of e/Q, while its time-average is valid in the first order. So the formula cannot be used for analysis in higher orders of e/Q. This necessitates corrections in the theory of tidal despinning and libration damping. We prove that when the inclination is low and phase lags are linear in frequency, the Kaula series is equivalent to a corrected version of the MacDonald method. The correction to MacDonald's approach would be to set the phase lag of the integral bulge proportional to the instantaneous frequency. The equivalence of descriptions gets violated by a nonlinear frequency-dependence of the lag. We explain that both the MacDonald- and Darwin-torque-based derivations of the popular formula for the tidal despinning rate are limited to low inclinations and to the phase lags being linear in frequency. The Darwin-torque-based derivation, though, is general enough to accommodate both a finite inclination and the actual rheology. Although rheologies with Q scaling as the frequency to a positive power make the torque diverge at a zero frequency, this reveals not the impossible nature of the rheology, but a flaw in mathematics, i.e., a common misassumption that damping merely provides lags to the terms of the Fourier series for the tidal potential. A hydrodynamical treatment (Darwin 1879) had demonstrated that the magnitudes of the terms, too, get changed. Reinstating of this detail tames the infinities and rehabilitates the "impossible" scaling law (which happens to be the actual law the terrestrial planets obey at low frequencies).Comment: arXiv admin note: sections 4 and 9 of this paper contain substantial text overlap with arXiv:0712.105

Cosmology, Oscillating Physics and Oscilllating Biology

According to recent reports there is an excess correlation and an apparent regularity in the galaxy one-dimensional polar distribution with a characteristic scale of 128 $h^{-1}$ Mpc. This aparent spatial periodicity can be naturally explained by a time oscillation of the gravitational constant $G$. On the other hand, periodic growth features of bivalve and coral fossiles appear to show a periodic component in the time dependence of the number of days per year. In this letter we show that a time oscillating gravitational constant with similar period and amplitude can explain such a feature.Comment: 9 pages. latex using revtex. This revised version is supposed to be free of e-mail nois