9,336 research outputs found
Tagging mortality experiments on Pacific mackerel, Pneumatophorus japonicus
Two experiments were conducted to compare tagging mortality rates when Pacific mackerel are tagged using a traditional method and a modified method. Tagged and control fish in equal numbers were held in tanks on board the R/V ALASKA and observed for mortality. The experiments revealed mortality rates of 24% when the tag passes between the pterygiophores or neural spines and 1.5% when the tag is placed in the lateral musculature. Mortality from handling the fish for tagging was 4%, tank trauma was 2%, and the initial tag loss was 2.5%. (20pp.
Results of the jack mackerel subpopulation discrimination feasibility study
A report is made on the feasibility of discriminating subpopulations of jack mackerel, Trachurus symmetricus, off of the southern California and Baja California coast. Histochemical, morphometric, and meristic characters are compared from four samples of approximately 200 fish each taken from three areas. The data are analyzed for homogeneity by chi-square tests. Heterogeneity was found only in anal fin ray counts. Recommendations for a comprehensive study are made. (16pp.
Results of a study to detect spawning marks in otoliths of Northern anchovy, Engraulis mordax
An attempt was made to detect spawning marks on the
otoliths (sagittae) of the northern anchovy, Engraulis
mordax, from waters of the Southern California Bight.
While no spawning marks were detected, a modification of
an existing technique for observing daily growth rings
was developed. A discussion is presented on detecting
spawning checks in the northern anchovy. (15pp.
Results of Jack Mackerel tagging study, 1971-75
Methods and materials used to tag and recapture jack mackerel, Trachurus symmetricus, off the coast of southern Ca1ifornia and Baja California, Mexico, are described. Tagging, recapture, and movement data resulting from this program are reported. Analysis of these data indicates substantial movement of jack mackerel within the range of the California
fishery and suggests a seasonal inshore-offshore movement
pattern. (13pp.
Indeterminacy and the Data of Introspection
The author of this paper argues that Searleās introspective critique of Quineās indeterminacy thesis is not a blow to Quineās linguistic behaviorism. The paper begins with a general picture of Quineās argument about the indeterminacy of language, as exhibited during radical translation but also in understanding one self. The author next pokes holes in the logic of Searleās conclusion that Quineās thesis is absurd and therefore incorrect. Searle, problematically, is too attached to his belief that there is such thing as determinate meaning. Instead, we must take up a contextualized understanding of meaning. Quineās findings do not lead to the conclusion that Searle thinks they do. Rather, they teach us something about how language, a totally effective communication practice, can break-down. Because Quineās main concern is effective language use, he does not err when he proposes face-value acceptance of the mother tongueāthe indeterminate is often effective enough
Dependence of Nebular Heavy-Element Abundance on H I Content for Spiral Galaxies
We analyze the galactic H I content and nebular log(O/H) for 60 spiral
galaxies in the Moustakas et al. (2006) spectral catalog. After correcting for
the mass-metallicity relationship, we show that the spirals in cluster
environments show a positive correlation for log(O/H) on DEF, the galactic H I
deficiency parameter, extending the results of previous analyses of the Virgo
and Pegasus I clusters. Additionally, we show for the first time that galaxies
in the field obey a similar dependence. The observed relationship between H I
deficiency and galactic metallicity resembles similar trends shown by
cosmological simulations of galaxy formation including inflows and outflows.
These results indicate the previously observed metallicity-DEF correlation has
a more universal interpretation than simply a cluster's effects on its member
galaxies. Rather, we observe in all environments the stochastic effects of
metal-poor infall as minor mergers and accretion help to build giant spirals.Comment: Accepted for publication in Ap
The beginnings of geography teaching and research in the University of Glasgow: the impact of J.W. Gregory
J.W. Gregory arrived in Glasgow from Melbourne in 1904 to take up the post of foundation Professor of Geology in the University of Glasgow. Soon after his arrival in Glasgow he began to push for the setting up of teaching in Geography in Glasgow, which came to pass in 1909 with the appointment of a Lecturer in Geography. This lecturer was based in the Department of Geology in the University's East Quad. Gregory's active promotion of Geography in the University was matched by his extensive writing in the area, in textbooks, journal articles and popular books. His prodigious output across a wide range of subject areas is variably accepted today, with much of his geomorphological work being judged as misguided to varying degrees. His 'social science' publications - in the areas of race, migration, colonisation and economic development of Africa and Australia - espouse a viewpoint that is unacceptable in the twenty-first century. Nonetheless, that viewpoint sits squarely within the social and economic traditions of Gregory's era, and he was clearly a key 'Establishment' figure in natural and social sciences research in the first half of the twentieth century. The establishment of Geography in the University of Glasgow remains enduring testimony of J.W. Gregory's energy, dedication and foresight
Unsupervised Feature Learning through Divergent Discriminative Feature Accumulation
Unlike unsupervised approaches such as autoencoders that learn to reconstruct
their inputs, this paper introduces an alternative approach to unsupervised
feature learning called divergent discriminative feature accumulation (DDFA)
that instead continually accumulates features that make novel discriminations
among the training set. Thus DDFA features are inherently discriminative from
the start even though they are trained without knowledge of the ultimate
classification problem. Interestingly, DDFA also continues to add new features
indefinitely (so it does not depend on a hidden layer size), is not based on
minimizing error, and is inherently divergent instead of convergent, thereby
providing a unique direction of research for unsupervised feature learning. In
this paper the quality of its learned features is demonstrated on the MNIST
dataset, where its performance confirms that indeed DDFA is a viable technique
for learning useful features.Comment: Corrected citation formattin
A determination of the spin-orbit alignment of the anomalously dense planet orbiting HD 149026
We report 35 radial velocity measurements of HD 149026 taken with the Keck Telescope. Of these measurements, 15
were made during the transit of the companion planet HD 149026b, which occurred on 2005 June 25. These velocities
provide a high-cadence observation of the Rossiter-McLaughlin effect, the shifting of photospheric line profiles that occurs when a planet occults a portion of the rotating stellar surface. We combine these radial velocities with previously published radial velocity and photometric data sets and derive a composite best-fit model for the star-planet system. This model confirms and improves previously published orbital parameters, including the remarkably small planetary radius, the planetary mass, and the orbital inclination, found to be Rp/RJup = 0.718 Ā± 0.065, Mp/MJup = 0.352 Ā± 0.025, and I = 86.1Ā° Ā± 1.4Ā°, respectively. Together the planetary mass and radius determinations imply a mean planetary density
of 1.18(-0.30)(+0.38)g cm(-3). The new data also allow for the determination of the angle between the apparent stellar equator and the orbital plane, which we constrain to be Ī» = -12Ā° Ā± 15Ā°
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