3,718 research outputs found
Evidence of Walleye Spawning in Maumee Bay, Lake Erie
Author Institution: Department of Fisheries and Wildlife, Michigan State University ; Single Spin Guide Service ; Ohio Department of Natural Resources, Division of Wildlife, Sandusky Fisheries Research UnitDuring the mid-1990s, anglers reported large numbers of walleye (Stizostedion vitreum) in spawning condition concentrated on shallow points adjacent to the Maumee River channel during spring. These fish had flowing eggs and semen and were suspected to be actively spawning in Maumee Bay. To investigate the potential of walleye spawning, we used a benthic pump to sample for eggs at five sites adjacent to the Maumee River channel and one site near Turtle Island in Maumee Bay on 5 April 1998, a time when walleye were actively spawning in rivers and on mid-lake reefs. We found walleye eggs at each of the six sites sampled. Relative abundance of eggs ranged from 17 to 2,105 per 2-min sample, with a mean of 459 (±232). Egg viability ranged from 33 to 54% across the sites and 10% of the viable walleye eggs were observed to be in late stages of embryonic development indicating that egg survival to hatching is likely. These results are the first documentation of walleye spawning in Maumee Bay, indicating that Maumee Bay is a viable spawning location for walleye, possibly representing an important source of recruitment for the Lake Erie stock
The Multiwavelength Survey By Yale-Chile (MUSYC) Wide K-Band Imaging, Photometric Catalogs, Clustering, And Physical Properties Of Galaxies At Z Similar To 2
We present K-band imaging of two similar to 30' x 30' fields covered by the Multiwavelength Survey by Yale-Chile (MUSYC) Wide NIR Survey. The SDSS 1030+05 and Cast 1255 fields were imaged with the Infrared Side Port Imager (ISPI) on the 4 m Blanco telescope at the Cerro Tololo Inter-American Observatory (CTIO) to a 5 sigma point-source limiting depth of K similar to 20 (Vega). Combining these data with the MUSYC optical UBVRIz imaging, we created multiband K-selected source catalogs for both fields. These catalogs, together with the MUSYC K-band catalog of the Extended Chandra Deep Field South (ECDF-S) field, were used to select K 20 BzK galaxies over an area of 0.71 deg(2). This is the largest area ever surveyed for BzK galaxies. We present number counts, redshift distributions, and stellar masses for our sample of 3261 BzK galaxies (2502 star-forming [sBzK] and 759 passively evolving [pBzK]), as well as reddening and star formation rate estimates for the star-forming BzK systems. We also present two-point angular correlation functions and spatial correlation lengths for both sBzK and pBzK galaxies and show that previous estimates of the correlation function of these galaxies were affected by cosmic variance due to the small areas surveyed. We have measured correlation lengths r(0) of 8.89 +/- 2.03 and 10.82 +/- 1.72 Mpc for sBzK and pBzK galaxies, respectively. This is the first reported measurement of the spatial correlation function of passive BzK galaxies. In the Lambda CDM scenario of galaxy formation, these correlation lengths at z similar to 2 translate into minimum masses of similar to 4 x 10(12) and similar to 9 x 10(12) M(circle dot) for the dark matter halos hosting sBzK and pBzK galaxies, respectively. The clustering properties of the galaxies in our sample are consistent with their being the descendants of bright Lyman break galaxies at z similar to 3, and the progenitors of present-day > 1L* galaxies.Astronom
Piston-ring film thickness: theory and experiment compared
A review of the published literature has demonstrated a large variability and discrepancies in the measured and predicted values of piston-ring lubricating film thickness in internal combustion engines. Only 2 papers have been found that compare experiments in firing engines directly with outputs from sophisticated ring-pack lubrication models. The agreement between theory and experiment in these comparisons was limited, possibly because of inadequacies in the models and/ or inaccuracies of measurement. This paper seeks to contribute to the literature by comparing accurately calibrated experimental measurements of piston-ring film thickness in a firing engine with predictions from an advanced, commercial software package alongside details of the systematic analysis of the measurement errors in this process. Suggestions on how measurement accuracy could be further improved are also given. Measurements of oil film thickness with an error (standard deviation) of +/-15% have been achieved. It is shown that this error can be reduced further, by changes in the design and installation of the sensors.
Detailed experimental measurements of film thickness under the top compression ring in a firing petrol engine have been made and compared with the predictions from a commercial, state-of-the art modelling package. The agreement between theory and experiment is excellent throughout the stroke in most cases, but some significant differences are observed at the lower load conditions. These differences are as yet unexplained, but may be due to the sensor topography influencing the hydrodynamic lubrication, lubricant availability, out-of-roundness in the cylinder, or squeeze effects. This a topic that requires further stud
Ariel - Volume 10 Number 1
Executive Editors
Madalyn Schaefgen
David Reich
Business Manager
David Reich
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Medical College
Edward Zurad
CAHS
John Guardiani
World
Mark Zwanger
Features Editors
Meg Trexler
Jim O\u27Brien
Editorials Editor
Jeffrey Banyas
Photography and Sports Editor
Stuart Singer
Commons Editor
Brenda Peterso
Scientific mindfulness: a foundation for future themes in international business
We conceptualize new ways to qualify what themes should dominate the future IB
research agenda by examining three questions: Whom should we ask? What should we ask and which selection criteria should we apply? What are the contextual forces? We propose scientific mindfulness as the way forward for generating themes in IB research
The Impact of Acquiring Unrestricted Work Authorization on Romanian and Bulgarian Migrants in the United Kingdom
When Romania and Bulgaria (the so-called A2 countries) joined the European Union in 2007, the United Kingdom imposed temporary restrictions on the employment and welfare entitlements of A2 citizens that lasted until January 1, 2014. This article analyzes the impact of the removal of these restrictions on the labor market outcomes and use of welfare benefits of A2 migrants. Applying difference-in-difference analysis to data from the UK’s Labour Force Survey, the results suggest that acquiring unrestricted work authorization had a significant negative impact on the incidence of self-employment among A2 migrants but there are no discernible effects on other labor market outcomes or on their receipt of a range of welfare benefits. The article offers potential explanations for these results
G313.3+00.3: A New Planetary Nebula discovered by the Australia Telescope Compact Array and the Spitzer Space Telescope
We present a new planetary nebula, first identified in images from the
Australia Telescope Compact Array, although not recognized at that time. Recent
observations with the Spitzer Space Telescope during the GLIMPSE Legacy program
have rediscovered the object. The high-resolution radio and infrared images
enable the identification of the central star or its wind, the recognition of
the radio emission as thermal, and the probable presence of polycylic aromatic
hydrocarbons in and around the source. These lead to the conclusion that
G313.3+00.3 is a planetary nebula. This object is of particular interest
because it was discovered solely through radio and mid-infrared imaging,
without any optical (or near-infrared) confirmation, and acts as a proof of
concept for the discovery of many more highly extinguished planetary nebulae.
G313.3+00.3 is well-resolved by both the instruments with which it was
identified, and suffers extreme reddening due to its location in the
Scutum-Crux spiral arm.Comment: 18 pages, LaTeX (aastex), incl. 8 PostScript (eps) figures and 1
table. Accepted by ApJ (Part 1
Bostonia: The Boston University Alumni Magazine. Volume 9
Founded in 1900, Bostonia magazine is Boston University's main alumni publication, which covers alumni and student life, as well as university activities, events, and programs
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