Novel fluid materials for CMOS photonic WDM systems

We propose a simple and low-cost WDM (Wavelength division multiplexing) system (Fig 1a) based on novel fluid materials using micro-ring multichannel filter design with in-situ, electrically and magnetically tunable, integrated 2D liquid crystal nanocomposite materials. We achieved a quality factor on the order of 10# − 10% and fine tuning within the entire C-band range.Engineering and Physical Sciences Research Council (EPSRC

An Anderson-Fano Resonance and Shake-Up Processes in the Magneto-Photoluminescence of a Two-Dimensional Electron System

We report an anomalous doublet structure and low-energy satellite in the magneto-photoluminescence spectra of a two-dimensional electron system. The doublet structure moves to higher energy with increasing magnetic field and is most prominent at odd filling factors 5 and 3. The lower-energy satellite peak tunes to lower energy for increasing magnetic field between filling factor 6 and 2. These features occur at energies below the fundamental band of recombination originating from the lowest Landau level and display striking magnetic field and temperature dependence that indicates a many-body origin. Drawing on a recent theoretical description of Hawrylak and Potemski, we show that distinct mechanisms are responsible for each feature.Comment: 14 pages including 5 figures. To appear in the April 15th edition of Phy. Rev. B. rapid com

Multichannel Si Photonic Crystal filters with Fine-Tuning Capability of Individual Channels for WDM optical interconnects

This is the author accepted manuscriptWe demonstrate a simple, low-cost solution for a single multi-channel WDM (Wavelength Division Multiplexing) filter with fine-tuning capability at the level of the individual channels. The filter is based on silicon photonic crystal and microfluidic technologies and can be integrated with CMOS processes.Engineering and Physical Sciences Research Council (EPSRC

Global effects in quaternionic quantum field theory

We present some striking global consequences of a model quaternionic quantum field theory which is locally complex. We show how making the quaternionic structure a dynamical quantity naturally leads to the prediction of cosmic strings and non-baryonic hot dark matter candidates.Comment: 11 pages, no figures, revte

Heritability of Clinical Mastitis Incidence and Relationships with Sire Transmitting Abilities for Somatic Cell Score, Udder Type Traits, Productive Life, and Protein Yield

The objective of this study was to determine the relationships among daughter clinical mastitis during first and second lactations and sire transmitting abilities for somatic cell score, udder type traits, productive life, and protein yield. Data on clinical mastitis during first lactation were available for 1795 daughters (in six Pennsylvania herds, one Minnesota herd, and one Nebraska herd) of 283 Holstein sires. Data on clinical mastitis during second lactation were available for 1055 of these daughters. A total of 479 cows had 864 clinical episodes during first lactation, and 230 cows had 384 clinical episodes during second lactation. Clinical mastitis incidence and the total number of clinical episodes during each lactation were regressed on herd-season of calving (a classification variable), age at first calving, lactation length, and sire transmitting abilities taken one at a time. Linear effects, nonlinear effects, and odds ratios were estimated for sire transmitting abilities. Separate analyses were conducted on dependent variables that considered clinical mastitis from: all organisms, coagulase-negative staphylococci, coliform species, streptococci other than Streptococcus agalactiae, and the most common environmental organisms (coliform species and streptococci other than Streptococcus agalactiae). Heritability of clinical mastitis ranged from 0.01 to 0.42. Daughters of sires that transmit the lowest somatic cell score had the lowest incidence of clinical mastitis and the fewest clinical episodes during first and second lactations. Daughters of sires that transmit longer productive life, shallower udders, deeper udder cleft, and strongly attached fore udders had either fewer clinical episodes or lower clinical mastitis incidence during first and second lactations. The incidence of clinical mastitis and the number of clinical episodes per lactation may be reduced by selection for lower somatic cell score, longer productive life, shallower udders, deeper udder cleft, or strongly attached fore udders

Hot dense capsule implosion cores produced by z-pinch dynamic hohlraum radiation

Hot dense capsule implosions driven by z-pinch x-rays have been measured for the first time. A ~220 eV dynamic hohlraum imploded 1.7-2.1 mm diameter gas-filled CH capsules which absorbed up to ~20 kJ of x-rays. Argon tracer atom spectra were used to measure the Te~ 1keV electron temperature and the ne ~ 1-4 x10^23 cm-3 electron density. Spectra from multiple directions provide core symmetry estimates. Computer simulations agree well with the peak compression values of Te, ne, and symmetry, indicating reasonable understanding of the hohlraum and implosion physics.Comment: submitted to Phys. Rev. Let

Radiocarbon as a novel tracer of extra-Antarctic feeding in Southern Hemisphere Humpback Whales

Bulk stable isotope analysis provides information regarding food web interactions, and has been applied to several cetacean species for the study of migration ecology. One limitation in bulk stable isotope analysis arises when a species, such as Southern hemisphere humpback whales, utilises geographically distinct food webs with differing isotopic baselines. Migrations to areas with different baselines can result in isotopic changes that mimic changes in feeding relations, leading to ambiguous food web interpretations. Here, we demonstrate the novel application of radiocarbon measurement for the resolution of such ambiguities. Radiocarbon was measured in baleen plates from humpback whales stranded in Australia between 2007 and 2013, and in skin samples collected in Australia and Antarctica from stranded and free-ranging animals. Radiocarbon measurements showed lower values for Southern Ocean feeding than for extra-Antarctic feeding in Australian waters. While the whales mostly relied on Antarctic-derived energy stores during their annual migration, there was some evidence of feeding within temperate zone waters in some individuals. This work, to our knowledge, provides the first definitive biochemical evidence for supplementary feeding by southern hemisphere humpback whales within temperate waters during migration. Further, the work contributes a powerful new tool (radiocarbon) for tracing source regions and geographical feeding

Identification of A-colored Stars and Structure in the Halo of the Milky Way from SDSS Commissioning Data

A sample of 4208 objects with magnitude 15 < g* < 22 and colors of main sequence A stars has been selected from 370 square degrees of Sloan Digital Sky Survey (SDSS) commissioning observations. The data is from two long, narrow stripes, each with an opening angle of greater than 60 deg, at Galactic latitudes 36 < abs(b) < 63 on the celestial equator. An examination of the sample's distribution shows that these stars trace considerable substructure in the halo. Large overdensities of A-colored stars in the North at (l,b,R) = (350, 50, 46 kpc) and in the South at (157, -58, 33 kpc) and extending over tens of degrees are present in the halo of the Milky Way. Using photometry to separate the stars by surface gravity, both structures are shown to contain a sequence of low surface gravity stars consistent with identification as a blue horizontal branch (BHB). Both structures also contain a population of high surface gravity stars two magnitudes fainter than the BHB stars, consistent with their identification as blue stragglers (BSs). From the numbers of detected BHB stars, lower limits to the implied mass of the structures are 6x10^6 M_sun and 2x10^6 M_sun. The fact that two such large clumps have been detected in a survey of only 1% of the sky indicates that such structures are not uncommon in the halo. Simple spheroidal parameters are fit to a complete sample of the remaining unclumped BHB stars and yield (at r < 40 kpc) a fit to a halo distribution with flattening (c/a = 0.65+/-0.2) and a density falloff exponent of alpha = -3.2+/-0.3.Comment: AASTeX v5_0, 26 pages, 1 table, 20 figures, ApJ accepte

Camaronesite, [Fe^(3+)(H_2O)_2(PO_3OH)]_2(SO_4)•1-2H_2O, a new phosphate-sulfate from the Camarones Valley, Chile, structurally related to taranakite

Camaronesite (IMA 2012-094), [Fe^(3+)(H_2O)_2(PO_3OH)]_2(SO_4)•1-2H_2O, is a new mineral from near the village of Cuya in the Camarones Valley, Arica Province, Chile. The mineral is a low-temperature, secondary mineral occurring in a sulfate assemblage with anhydrite, botryogen, chalcanthite, copiapite, halotrichite, hexahydrite, hydroniumjarosite, pyrite, römerite, rozenite and szomolnokite. Lavender-coloured crystals up to several mm across form dense intergrowths. More rarely crystals occur as drusy aggregates of tablets up to 0.5 mm in diameter and 0.02 mm thick. Tablets are flattened on {001} and exhibit the forms {001}, {104}, {015} and {018}. The mineral is transparent with white streak and vitreous lustre. The Mohs hardness is 2½, the tenacity is brittle and the fracture is irregular, conchoidal and stepped. Camaronesite has one perfect cleavage on {001}. The measured and calculated densities are 2.43(1) and 2.383 g/cm^3, respectively. The mineral is optically uniaxial (+) with ω = 1.612(1) and ε = 1.621(1) (white light). The pleochroism is O (pale lavender) > E (colourless). Electron-microprobe analyses provided Fe_2O_331.84, P_2O_529.22, SO_315.74, H_2O 23.94 (based on O analyses), total 100.74 wt.%. The empirical formula (based on 2 P a.p.f.u.) is: Fe_(1.94)(PO_3OH)_2(S_(0.96)O_4)(H_2O)_4•1.46H_2O. The mineral is slowly soluble in concentrated HCl and extremely slowly soluble in concentrated H_2SO_4. Camaronesite is trigonal, R32, with cell parameters:a = 9.0833(5), c = 42.944(3) Å, V = 3068.5(3) Å3 and Z = 9. The eight strongest lines in the X-ray powder diffraction pattern are [d_(obs) Å (I)(hkl)]: 7.74(45)(101), 7.415(100)(012), 4.545(72)(110), 4.426(26)(018), 3.862(32)(021,202,116), 3.298(93)(027,119), 3.179(25)(208) and 2.818(25)(1•1•12,125). In the structure of camaronesite (R_1 = 2.28% for 1138 F_o > 4σF), three types of Fe octahedra are linked by corner sharing with (PO_3OH) tetrahedra to form polyhedral layers perpendicular to c with composition [Fe^(3+)(H_2O)_2(PO_3OH)]. Two such layers are joined through SO_4 tetrahedra (in two half-occupied orientations) to form thick slabs of composition [Fe^(3+)(H_2O)_2(PO_3OH)]_2(SO_4). Between the slabs are partially occupied H_2O groups. The only linkages between the slabs are hydrogen bonds. The most distinctive component in the structure consists of two Fe octahedra linked to one another by three PO_4 tetrahedra yielding an [Fe_2(PO_4)_3] unit. This unit is also the key component in the sodium super-ionic conductor (NASICON) structure and has been referred to as the lantern unit. The polyhedral layers in the structure of camaronesite are similar to those in the structure of taranakite. The Raman spectrum exhibits peaks consistent with sulfate, phosphate, water and OH groups