1,652 research outputs found
Fraud on Any Market
Claims of securities fraud had historically failed because investors seldom rely on false or misleading statements when transacting securities. To bolster confidence in securities markets, the U.S. Supreme Court adopted a doctrine called “fraud-on-the-market” so that duped investors can show detrimental reliance without ever encountering the fraudulent statements. The doctrine assumes that a stock’s price reflects all material information, meaning that an investor who bought tainted stock has constructively relied on the fraud.
Fraud-on-the-market is not only unavailable in other markets but is also embattled within securities law. The doctrine has endured volleys of criticisms about whether markets actually absorb information, leading critics to believe that the Supreme Court would eliminate it in 2014. The Court did not. In light of persistent questions about whether the doctrine reflects reality or has outlived its purpose, our empirical research tests fraud-on-the-market’s viability by investigating sports gambling: we find that the doctrine provides a sound remedy for investors in any market.
The sports wagering market operates like others in which defrauded individuals have historically failed to support their fraud claims due to a lack of reliance. We show that securities and gambling markets suffer from many of the same frailties. Chief among them is that both investors and bettors place money in markets where they lack information about deception, cheating, and fraud. And like investors rely on prices affected by fraud, gamblers reference wagering information based on the playing field: if deception enables a team to fare better or worse, this skews the betting lines on which gamblers rely. The difference between these markets, though, is that investors enjoy a body of securities law to condemn fraud.
We first argue that fraud-on-the-market would benefit most types of investable markets like sports gambling and support the doctrine in the securities context. Despite criticisms of the doctrine, our analysis shows that fraud creates the presumption of distorted prices. Second, the money wagered via sports betting and daily fantasy sports (DFS) would generate damages such that leagues would better maintain a competitive environment, boosting sports integrity akin to how securities regulations provide market protections. Also, our argument recognizes the inequity of denying sports bettors and DFS users a remedy. Whereas the leagues had traditionally benefited from gambling indirectly, today, the NFL, NHL, MLB, and NBA have partnered with DFS and other gambling industry companies. Since the leagues now benefit directly from gambling, and lucratively so, they should owe their fans a truly competitive landscape
Dietary Habits of the Common Rodents in an Agrecosystem in Argentina
Dietary habits of five common rodents in agroecosystems on the central Argentine Pampa were studied for 15 months using microhistological analysis of stomach contents. All five rodent species were omnivorous, but proportions of major dietary items (arthropods, dicot leaves and seeds, monocot leaves and seeds) varied among species and seasons. Akodon azarae largely was entomophagous; arthropods formed 41-62% of the diet in all seasons. The other four species (Calomys musculinus, Calomys laucha, Bolomys obscurus, and Oligoryzomys flavescens) consumed most diet items throughout the year, but relative proportions varied among seasons. Leaves formed a relatively minor proportion of the diet (12- 16% overall for all species) throughout the year. All species except A. azarae consumed higher quantities of seeds (50-73% of stomach volume) than arthropods (15-35%) during autumn and winter but switched to higher quantities of arthropods (30-53%) in spring and summer. Diet breadth was narrower and overlap generally highest during winter when all species were forced to subsist on a reduced set of available resources. Of 28 plant species with \u3e2% cover in the environment, 25 were identified in stomachs of one or more of the five rodent species. The most important plant species in the diet were corn and soybeans (mostly grain), seed of Johnson grass (Sorghum halepense), chickweed (Stellaria media), and Amaranthus. High consumption of arthropods, especially by A. azarae, contraindicates the broad-scale use of rodenticides until the role of that rodent species in the control of pest insects can be ascertained
Dietary Habits of the Common Rodents in an Agrecosystem in Argentina
Dietary habits of five common rodents in agroecosystems on the central Argentine Pampa were studied for 15 months using microhistological analysis of stomach contents. All five rodent species were omnivorous, but proportions of major dietary items (arthropods, dicot leaves and seeds, monocot leaves and seeds) varied among species and seasons. Akodon azarae largely was entomophagous; arthropods formed 41-62% of the diet in all seasons. The other four species (Calomys musculinus, Calomys laucha, Bolomys obscurus, and Oligoryzomys flavescens) consumed most diet items throughout the year, but relative proportions varied among seasons. Leaves formed a relatively minor proportion of the diet (12- 16% overall for all species) throughout the year. All species except A. azarae consumed higher quantities of seeds (50-73% of stomach volume) than arthropods (15-35%) during autumn and winter but switched to higher quantities of arthropods (30-53%) in spring and summer. Diet breadth was narrower and overlap generally highest during winter when all species were forced to subsist on a reduced set of available resources. Of 28 plant species with \u3e2% cover in the environment, 25 were identified in stomachs of one or more of the five rodent species. The most important plant species in the diet were corn and soybeans (mostly grain), seed of Johnson grass (Sorghum halepense), chickweed (Stellaria media), and Amaranthus. High consumption of arthropods, especially by A. azarae, contraindicates the broad-scale use of rodenticides until the role of that rodent species in the control of pest insects can be ascertained
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Volcanic Radiative Forcing From 1979 to 2015
Using volcanic sulfur dioxide emissions in an aerosol-climate model we derive a time-series of global-mean volcanic effective radiative forcing (ERF) from 1979 to 2015. For 2005-2015, we calculate a global multi-annual mean volcanic ERF of 0.08 W m 2 relative to the volcanically quiescent 1999-2002 period, due to a high frequency of small-to-moderate-magnitude explosive eruptions after 2004. For eruptions of large magnitude such as 1991 Mt. Pinatubo, our model-simulated volcanic ERF, which accounts for rapid adjustments including aerosol perturbations of clouds, is less negative than that reported in the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5) that only accounted for stratospheric temperature adjustments. We find that, when rapid adjustments are considered, the relation between volcanic forcing and volcanic stratospheric optical depth (SAOD) is 13-21% weaker than reported in IPCC AR5 for large-magnitude eruptions. Further, our analysis of the recurrence frequency of eruptions reveals that sulfur-rich small-to-moderate-magnitude eruptions with column heights 10 km occur frequently, with periods of volcanic quiescence being statistically rare. Small-to-moderate-magnitude eruptions should therefore be included in climate model simulations, given the 50% chance of one or two eruptions to occur in any given year. Not all of these eruptions affect the stratospheric aerosol budget, but those that do increase the non-volcanic background SAOD by ~0.004 on average, contributing ~50% to the total SAOD in the absence of large-magnitude eruptions. This equates to a volcanic ERF of about 0.10 W m 2, which is about two-thirds of the ERF from ozone changes induced by ozone-depleting substances
A Brief History of AGN
Astronomers knew early in the twentieth century that some galaxies have
emission-line nuclei. However, even the systematic study by Seyfert (1943) was
not enough to launch active galactic nuclei (AGN) as a major topic of
astronomy. The advances in radio astronomy in the 1950s revealed a new universe
of energetic phenomena, and inevitably led to the discovery of quasars. These
discoveries demanded the attention of observers and theorists, and AGN have
been a subject of intense effort ever since. Only a year after the recognition
of the redshifts of 3C 273 and 3C 48 in 1963, the idea of energy production by
accretion onto a black hole was advanced. However, acceptance of this idea came
slowly, encouraged by the discovery of black hole X-ray sources in our Galaxy
and, more recently, supermassive black holes in the center of the Milky Way and
other galaxies. Many questions remain as to the formation and fueling of the
hole, the geometry of the central regions, the detailed emission mechanisms,
the production of jets, and other aspects. The study of AGN will remain a
vigorous part of astronomy for the foreseeable future.Comment: 37 pages, no figures. Uses aaspp4.sty. To be published in
Publications of the Astronomical Society of the Pacific, 1999 Jun
A 22-year Southern Sky Survey for Transient and Variable Radio Sources using the Molonglo Observatory Synthesis Telescope
We describe a 22-year survey for variable and transient radio sources,
performed with archival images taken with the Molonglo Observatory Synthesis
Telescope (MOST). This survey covers 2775 \unit{deg^2} of the sky south of
at an observing frequency of 843 MHz, an angular
resolution of 45 \times 45 \csc | \delta| \unit{arcsec^2} and a sensitivity
of 5 \sigma \geq 14 \unit{mJy beam^{-1}}. We describe a technique to
compensate for image gain error, along with statistical techniques to check and
classify variability in a population of light curves, with applicability to any
image-based radio variability survey. Among radio light curves for almost 30000
sources, we present 53 highly variable sources and 15 transient sources. Only 3
of the transient sources, and none of the variable sources have been previously
identified as transient or variable. Many of our variable sources are suspected
scintillating Active Galactic Nuclei. We have identified three variable sources
and one transient source that are likely to be associated with star forming
galaxies at , but whose implied luminosity is higher than the
most luminous known radio supernova (SN1979C) by an order of magnitude. We also
find a class of variable and transient source with no optical counterparts.Comment: Accepted for publication in MNRAS. 34 pages, 30 figures, 7 table
Wide-Field Imaging and Polarimetry for the Biggest and Brightest in the 20GHz Southern Sky
We present wide-field imaging and polarimetry at 20GHz of seven of the most
extended, bright (Stot >= 0.50 Jy), high-frequency selected radio sources in
the southern sky with declinations < -30 deg. Accompanying the data are brief
reviews of the literature for each source, The results presented here aid in
the statistical completeness of the Australia Telescope 20GHz Survey's bright
source sample. The data are of crucial interest for future cosmic microwave
background missions as a collection of information about candidate calibrator
sources. We are able to obtain data for seven of the nine sources identified by
our selection criteria. We report that Pictor A is thus far the best
extragalactic calibrator candidate for the Low Frequency Instrument of the
Planck European Space Agency mission due to its high level of integrated
polarized flux density (0.50+/-0.06 Jy) on a scale of 10 arcmin. Six of the
seven sources have a clearly detected compact radio core, with either a null or
less than two percent detection of polarized emission from the nucleus. Most
sources with detected jets have magnetic field alignments running in a
longitudinal configuration, however PKS1333-33 exhibits transverse fields and
an orthogonal change in field geometry from nucleus to jets.Comment: 17 pages, 9 figures, 2 table
Genome size evolution at the speciation level: The cryptic species complex Brachionus plicatilis (Rotifera)
<p>Abstract</p> <p>Background</p> <p>Studies on genome size variation in animals are rarely done at lower taxonomic levels, e.g., slightly above/below the species level. Yet, such variation might provide important clues on the tempo and mode of genome size evolution. In this study we used the flow-cytometry method to study the evolution of genome size in the rotifer <it>Brachionus plicatilis</it>, a cryptic species complex consisting of at least 14 closely related species.</p> <p>Results</p> <p>We found an unexpectedly high variation in this species complex, with genome sizes ranging approximately seven-fold (haploid '1C' genome sizes: 0.056-0.416 pg). Most of this variation (67%) could be ascribed to the major clades of the species complex, i.e. clades that are well separated according to most species definitions. However, we also found substantial variation (32%) at lower taxonomic levels - within and among genealogical species - and, interestingly, among species pairs that are not completely reproductively isolated. In one genealogical species, called <it>B</it>. 'Austria', we found greatly enlarged genome sizes that could roughly be approximated as multiples of the genomes of its closest relatives, which suggests that whole-genome duplications have occurred early during separation of this lineage. Overall, genome size was significantly correlated to egg size and body size, even though the latter became non-significant after controlling for phylogenetic non-independence.</p> <p>Conclusions</p> <p>Our study suggests that substantial genome size variation can build up early during speciation, potentially even among isolated populations. An alternative, but not mutually exclusive interpretation might be that reproductive isolation tends to build up unusually slow in this species complex.</p
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