Evidence of the selection of tidal streams by northern rock sole (Lepidopsetta polyxystra) for transport in the eastern Bering Sea

Depth data from archival tags on northern rock sole (Lepidopsetta polyxystra) were examined to assess whether fish used tidal currents to aid horizontal migration. Two northern rock sole, out of 115 released with archival tags in the eastern Bering Sea, were recovered 314 and 667 days after release. Both fish made periodic excursions away from the bottom during mostly night-time hours, but also during particular phases of the tide cycle. One fish that was captured and released in an area of rotary currents made vertical excursions that were correlated with tidal current direction. To test the hypothesis that the fish made vertical excursions to use tidal currents to aid migration, a hypothetical migratory path was calculated using a tide model to predict the current direction and speed during periods when the fish was off the bottom. This migration included limited movements from July through December, followed by a 200-km southern migration from January through February, then a return northward in March and April. The successful application of tidal current information to predict a horizontal migratory path not only provides evidence of selective tidal stream transport but indicates that vertical excursions were conducted primarily to assist horizontal migration

WFMOS - Sounding the Dark Cosmos

Vast sound waves traveling through the relativistic plasma during the first million years of the universe imprint a preferred scale in the density of matter. We now have the ability to detect this characteristic fingerprint in the clustering of galaxies at various redshifts and use it to measure the acceleration of the expansion of the Universe. The Wide-Field Multi-Object Spectrograph (WFMOS) would use this test to shed significant light on the true nature of dark energy, the mysterious source of this cosmic acceleration. WFMOS would also revolutionise studies of the kinematics of the Milky Way and provide deep insights into the clustering of galaxies at redshifts up to z~4. In this article we discuss the recent progress in large galaxy redshift surveys and detail how WFMOS will help unravel the mystery of dark energy.Comment: 6 pages, pure pdf. An introduction to WFMOS and Baryon Acoustic Oscillations for a general audienc

[(1,2,5,6-η)-1,5-Cyclo­octa­diene](1-isopropyl-3-methyl­imidazolin-2-yl­idene)(triphenyl­phosphine)iridium(I) tetra­fluorido­borate dichloro­methane solvate

In the title compound, [Ir(C8H12)(C7H12N2)(C18H15P)]BF4·CH2Cl2, the Ir(I) atom has a square-planar conformation with normal bond lengths. One of the phenyl rings, and the solvent dichloro­methane mol­ecule, were refined using separate two part disorder models, each in an approximately 1:1 ratio

Canadian Families’ Decisions of Communication Options* for Children Who are Deaf or Hard of Hearing: An Initial Exploration

Communication is an essential aspect of human interaction and helps connect us to the people around us. The majority of children who are deaf or hard of hearing are born to hearing parents who are likely unfamiliar with hearing loss. These parents are then asked to make critical decisions about communication options for their children. It can be a challenging process but one that needs to be done quickly in order to capture the critical language development period. Little research has explored the factors associated with parents’ decisions about communication options for their children who are deaf or hard of hearing and no studies have been done specifically with Canadian parents. This exploratory survey design study examined the factors which influence Canadian parents’ decisions relative to communication options for their children who are deaf or hard of hearing. Results indicate that parents’ personal judgement and a desire for their child to be able to communicate with their family and be happy in their own unique lives were driving forces behind the decisions that were made. Confirming research conducted in other countries, Canadian parents use a combination of their own judgement, professionals’ opinions, the needs of their child and internal values to make communication option decisions. Implications of these results are discussed as they pertain to parent-professional partnerships and family-centered services

Grist: Grid-based Data Mining for Astronomy

The Grist project is developing a grid-technology based system as a research environment for astronomy with massive and complex datasets. This knowledge extraction system will consist of a library of distributed grid services controlled by a work ow system, compliant with standards emerging from the grid computing, web services, and virtual observatory communities. This new technology is being used to find high redshift quasars, study peculiar variable objects, search for transients in real time, and fit SDSS QSO spectra to measure black hole masses. Grist services are also a component of the "hyperatlas" project to serve high-resolution multi-wavelength imagery over the Internet. In support of these science and outreach objectives, the Grist framework will provide the enabling fabric to tie together distributed grid services in the areas of data access, federation, mining, subsetting, source extraction, image mosaicking, statistics, and visualization

Controlling the False Discovery Rate in Astrophysical Data Analysis

The False Discovery Rate (FDR) is a new statistical procedure to control the number of mistakes made when performing multiple hypothesis tests, i.e. when comparing many data against a given model hypothesis. The key advantage of FDR is that it allows one to a priori control the average fraction of false rejections made (when comparing to the null hypothesis) over the total number of rejections performed. We compare FDR to the standard procedure of rejecting all tests that do not match the null hypothesis above some arbitrarily chosen confidence limit, e.g. 2 sigma, or at the 95% confidence level. When using FDR, we find a similar rate of correct detections, but with significantly fewer false detections. Moreover, the FDR procedure is quick and easy to compute and can be trivially adapted to work with correlated data. The purpose of this paper is to introduce the FDR procedure to the astrophysics community. We illustrate the power of FDR through several astronomical examples, including the detection of features against a smooth one-dimensional function, e.g. seeing the ``baryon wiggles'' in a power spectrum of matter fluctuations, and source pixel detection in imaging data. In this era of large datasets and high precision measurements, FDR provides the means to adaptively control a scientifically meaningful quantity -- the number of false discoveries made when conducting multiple hypothesis tests.Comment: 15 pages, 9 figures. Submitted to A

Life history examination of darkblotched rockfish (Sebastes crameri) off the Oregon coast

The growth, size and age composition, mortality and reproduction of darkblotched rockfish (Sebastes crameri) were examined using fishery data and analysis of fish characteristics for samples collected of f the Oregon coast. A total of 1060 fish, caught by commercial groundfish and shrimp trawlers operating out of Newport, Coos Bay and Astoria, were collected between July 1986 and July 1987. S. crameri were found to be slow growing and longlived reaching ages in excess of 100 years. The composition of fish captured with commercial groundfish trawl gear (excluding shrimp gear) was dominated by recent recruits ranging from 6 to 9 years of age. The age at full recruitment to commercial groundfish gear was 7 years. Assuming constant recruitment and mortality after 1978, total instantaneous mortality (Z) for recent recruits may have been as high as 0.42. This estimate may be inflated, however, if the 1978-1980 yearclasses were strong relative to earlier yearclasses. The timing of major reproductive events was protracted. Insemination occurred from September to December, fertilization from December to February, and parturition from December to March. Fifty percent of the females were mature at an age of 8 years and a total length (TL) of 36.7 cm, whereas males attained 50% maturity at an age of 5 years and 29.7 cm TL. Fecundity increased nonlinearly with fish size and ranged from 19,815 to 489,064 oocytes/ovary pair. Based on its longevity, its relatively young age at full recruitment, and its age at maturity, S. crameri appears vulnerable to overexploitation