360 research outputs found
Recommended from our members
Spam Works: Evidence from Stock Touts and Corresponding Market Activity
We assess the impact of spam that touts stocks upon the trading activity of those stocks and sketch how profitable such spamming might be for spammers and how harmful it is to those who heed advice in stock-touting e-mails. We find convincing evidence that stock prices are being manipulated through spam. We suggest that the effectiveness of spammed stock touting calls into question prevailing models of securities regulation that rely principally on the proper labeling of information and disclosure of conflicts of interest as means of protecting consumers, and we propose several regulatory and industry interventions.
Based on a large sample of touted stocks listed on the Pink Sheets quotation system and a large sample of spam emails touting stocks, we find that stocks experience a significantly positive return on days prior to heavy touting via spam. Volume of trading
responds positively and significantly to heavy touting. For a stock that is touted at some point during our sample period, the probability of it being the most actively traded stock in our sample jumps from 4% on a day when there is no touting activity to 70% on a day when there is touting activity. Returns in the days following touting are significantly negative. The evidence accords with a hypothesis that spammers "buy low and spam high," purchasing penny stocks with comparatively low liquidity, then touting them - perhaps immediately after an independently occurring upward tick in price, or after having caused the uptick themselves by engaging in preparatory purchasing - in order to increase or maintain trading activity and price enough to unload their positions at a profit. We find that prolific spamming greatly affects the trading volume of a targeted stock, drumming up buyers to prevent the spammer's initial selling from depressing the stock's price. Subsequent selling by the spammer (or others) while this buying pressure subsides results in negative returns following touting. Before brokerage fees, the average investor who buys a stock on the day it is most heavily touted and sells it 2 days after the touting ends will lose close to 5.5%. For those touted stocks with above-average levels of touting, a spammer who buys on the day before unleashing touts and sells on the day his or her touting is the heaviest, on average, will earn 4.29% before transaction costs. The underlying data and interactive charts showing price and volume changes are also made available
Nanometer-Resolved Collective Micromeniscus Oscillations through Optical Diffraction
We study the dynamics of periodic arrays of micrometer-sized liquid-gas
menisci formed at superhydrophobic surfaces immersed into water. By measuring
the intensity of optical diffraction peaks in real time we are able to resolve
nanometer scale oscillations of the menisci with sub-microsecond time
resolution. Upon driving the system with an ultrasound field at variable
frequency we observe a pronounced resonance at a few hundred kHz, depending on
the exact geometry. Modeling the system using the unsteady Stokes equation, we
find that this low resonance frequency is caused by a collective mode of the
acoustically coupled oscillating menisci.Comment: 4 pages, 5 figure
New formula for a resonant scattering near an inelastic threshold
We show that the Flatte formula is not adequate to interpret precision data
on a resonance production near an inelastic threshold. A unitary
parameterization, satisfying generalized Watson's theorem for the production
amplitudes, is proposed to replace the Flatte parameterization in
phenomenological analyses of experimental data.Comment: 6 pages, 2 figures, contributed to SCADRON 70, Workshop on Scalar
Mesons and Related Topics, February 11-16, 2008, Lisbon, Portuga
Scalar Mesons in Charm Decays
Results on light scalar mesons in charmed particle decays studied by the CLEO
Collaboration at the Cornell Electron Storage Ring are reviewed.Comment: 10 pages, 9 figures, invited talk presented at SCADRON 70 (Workshop
on Scalar Mesons and Related Topics, Losbon, 11-16 February 2008
High prevalence of ESBL-producing Klebsiella pneumoniae in clinical samples from central CĂŽte d'Ivoire
Objectives: Infections caused by multidrug-resistant Enterobacterales pose a significant challenge to clinical patient care, particularly in resource-constrained settings where epidemiological data on antimicrobial resistance are scarce. The aim of this study was to determine the prevalence of extended spectrum beta-lactamase-(ESBL)-producing Klebsiella pneumoniae among clinical samples from a teaching hospital in BouakĂ©, central CĂŽte dâIvoire. Methods: Clinical specimens were collected from sterile and non-sterile body sites and were subjected to microbiological diagnostics (April 2016-June 2017). The antimicrobial susceptibility patterns of K. pneumoniae were analysed using automated resistance testing and double-disk diffusion to test for ESBL production. Multiplex PCR was carried out to determine the presence of the resistance-conferring genes blaCTX-M, blaSHV and blaTEM. Results: A total of 107 isolates were included, most of which were obtained from bloodstream (39%; nâ
=â
42) and urinary tract infections (39%; nâ
=â
42). Among all K. pneumoniae isolates, 84% (nâ
=â
90) were ESBL producers, many of which were also not susceptible to sulfonamides (99%), quinolones (81%) and aminoglycosides (79%). The majority of ESBL-producing strains harboured all three investigated bla genes. Conclusion: The high prevalence of ESBL-producing K. pneumoniae in clinical isolates from CĂŽte dâIvoire calls for revised empirical treatment regimens in critically ill patients with suspected Gram-negative infections, and the establishment of antimicrobial resistance surveillance systems
Recommended from our members
Intravenous tPA therapy does not worsen acute intracerebral hemorrhage in mice
Tissue plasminogen activator (tPA) is the only FDA-approved treatment for reperfusing ischemic strokes. But widespread use of tPA is still limited by fears of inadvertently administering tPA in patients with intracerebral hemorrhage (ICH). Surprisingly, however, the assumption that tPA will worsen ICH has never been biologically tested. Here, we assessed the effects of tPA in two models of ICH. In a mouse model of collagenase-induced ICH, hemorrhage volumes and neurological deficits after 24 hrs were similar in saline controls and tPA-treated mice, whereas heparin-treated mice had 3-fold larger hematomas. In a model of laser-induced vessel rupture, tPA also did not worsen hemorrhage volumes, while heparin did. tPA is known to worsen neurovascular injury by amplifying matrix metalloproteinases during cerebral ischemia. In contrast, tPA did not upregulate matrix metalloproteinases in our mouse ICH models. In summary, our experimental data do not support the assumption that intravenous tPA has a deleterious effect in acute ICH. However, due to potential species differences and the inability of models to fully capture the dynamics of human ICH, caution is warranted when considering the implications of these findings for human therapy
The Academics Athletics Trade-off: Universities and Intercollegiate Athletics
This analysis focuses on several key issues in the Football Bowl Subdivision (FBS). The intrinsic benefits of athletic programs are discussed in the first section. Trends in graduation rates and academic performance among athletes and how they correlate with the general student body are discussed in the second section. Finally, an overview of the revenues and expenses of athletic department budgets are discussed in an effort to gain a better understanding of the allocation of funds to athletics. In spite of recent growth in revenues and expenses, the athletic department budget comprises on average only 5 percent of the entire university budget at an FBS school, though spending and revenues have increased dramatically in recent years. In the grand scheme of things, American higher education faces several other, arguably more pressing, areas of reform. However, athletics is a significant and growing dimension of higher education that warrants in-depth examination
- âŠ