6,504 research outputs found
Call to the Bullpen: How the 2012 MLB Draft Shows Why the NCAA Must Make a Change to Its Bylaws
Major League Baseball (âMLBâ) revised its amateur draft rules in 2012, which had a significant effect on how much of a signing bonus MLB teams could offer their draftees. Accordingly, it is no surprise that signing bonuses for first round draftees decreased by almost $12 million in 2012, as compared to 2011. The new rules, and their subsequent effect on MLB teams, demand that baseball student-athletes, now more than ever, not only be educated in all facets of the MLB Draft before deciding to turn pro or become/remain college student-athletes, but also retain a competent attorney or agent to represent them in the negotiation of a professional contract. The problem is that current National Collegiate Athletic Association (âNCAAâ) rules make it virtually impossible for baseball student-athletes to receive the education they deserve to make a well-informed decision. Furthermore, NCAA rules completely prohibit student-athletes from hiring an attorney and/or agent for representation during negotiations. MLB revised its rules to address changes in professional baseball; the NCAA must follow suit and amend its outdated bylaws to be in tune with the current state of amateur baseball. This article argues that the NCAA should 1.) Make a âHigh School Baseball Exceptionâ to its no-agent rule, 2.) Reform its bylaw regarding Professional Sports Counseling Panels, 3.) Revise the no-agent rule as applied to college baseball student-athletes, and 4.) Create a National Professional Sports Counseling Panel
Influence of organic films on the evaporation and condensation of water in aerosol
Uncertainties in quantifying the kinetics of evaporation and condensation of water from atmospheric aerosol are a significant contributor to the uncertainty in predicting cloud droplet number and the indirect effect of aerosols on climate. The influence of aerosol particle surface composition, particularly the impact of surface active organic films, on the condensation and evaporation coefficients remains ambiguous. Here, we report measurements of the influence of organic films on the evaporation and condensation of water from aerosol particles. Significant reductions in the evaporation coefficient are shown to result when condensed films are formed by monolayers of long-chain alcohols [C(n)H((2n+1))OH], with the value decreasing from 2.4 Ă 10(â3) to 1.7 Ă 10(â5) as n increases from 12 to 17. Temperature-dependent measurements confirm that a condensed film of long-range order must be formed to suppress the evaporation coefficient below 0.05. The condensation of water on a droplet coated in a condensed film is shown to be fast, with strong coherence of the long-chain alcohol molecules leading to islanding as the water droplet grows, opening up broad areas of uncoated surface on which water can condense rapidly. We conclude that multicomponent composition of organic films on the surface of atmospheric aerosol particles is likely to preclude the formation of condensed films and that the kinetics of water condensation during the activation of aerosol to form cloud droplets is likely to remain rapid
Optimization of a bio-inspired sound localization sensor for high directional sensitivity
Miniaturization of sound localization sensors arrays is heavily constrained by the limited directional cues in intensity difference and phase difference available at the microscale. Micro-Electro Mechanical System (MEMS) sound localization sensors inspired by the auditory system of Ormia ochracea offer a potential solution to this problem by the apparent amplification of the available intensity and phase difference between the measurement points. An inherent limitation of these existing systems is that significant amplification of these cues is only available at or close to one of the resonant frequencies of the device, severely limiting it application as a directional microphone. Here we present the process of optimization of a sound localization sensor for the maximum amplification of directional cues across a narrow bandwidth, increasing the signal to noise ratio and the reading accuracy for sound localization measurements
Studies on fascioliasis and ostertagiasis in cattle and sheep
The work described in this thesis is concerned with two parasitic helminths, Fasciola hepatica and Ostertagia ostertagi. Although the major part of the thesis describes investigation into fascioliasis in both cattle and sheep, the first section records a hitherto undescribed condition in cattle where both F. hepatica and O. ostertagi coexisted in significant numbers.Single experimental onfections of cattle and sheep with metacercariae of F. hepatica were studied, and these were followed by observations on the sequential development of an outbreak of fascioliasis in sheep grazing under natural conditions, a subject investigated in detail for the first time. The final section describes a method of control by use of a fasciolicide. The thesis is divided into five sections as follows: Section I Field Studies on Clinical Parasitism in Young Dairy Cattle in South-west Scotland. The first part of this section reviews a series of out breaks of ostertagiasis occurring during the course of the winter (Type II). This is followed by the description of a further series of outbreaks of parasitic disease in which both O. ostertagi and F. hepatica were present in significant numbers (the fascioliasis/ostertagiasis complex). The two conditions had different background histories, seasonal incidences, clinical signs and necropsy findings, and these differences are discussed in detail. Section II Experimental Fasciola hepatica Infections in Calves. Single oral inoculations of susceptible calves with 1000 or 2000 metacercariae of F. hepatica resulted in the establishment of an adult fluke burden capable of producing clinical signs and death. The haematological and blood biochemical values recorded at weekly intervals demonstrated the presense of a macrocytic, normochromic anaemia and a hypoalbuminaemia. At post-mortem all but two of the infected calves showed a percentage take (i.e. the percentage of the inoculation which became established) of between 16% and 37%; the two remaining calves, given the higher level infection, showed very low percentage takes at necropsy. Section III Experimental Fasciola hepatica Infections in Sheep Inoculation of susceptible lambs with single oral doses of 1000 metacercariae of F. hepatica each resulted in the development of clinical fascioliasis followed by death between 12 and 23 weeks after infection. A severe, macrocytic, hypochromic anaemia was recorded commencing 5 to 6 weeks post-infection, the degree of anaemia being proportional to the number of flukes recovered at necropsy. Reticulocytes appeared in the peripheral circulation and a hypoalbuminaemia was also present. The percentage of the inoculum established ranged from 10.8% to 81.5%. An outbreak of clinical fascioliasis, in lambs grazing permanent pasture known to have been responsible for outbreaks of fascioliasis in sheep during the previous two years, commenced during the first part of October. The major clinical signs were weight loss and pallor of visible mucous membranes; a macrocytic, hypochromic anaemia developed with reticulocytes present in the peripheral circulation. A hypoalbuminaemia and in many cases a frank hypoproteinaemia was recorded in these lambs. The total number of F. hepatica recovered from individual animals at necropsy ranged from 110 to 1628. Concurrent studies on the changes in pasture populations of metacercariae of F. hepatica revealed that the maximum number of metacercariae was available between mid-August and mid-September although metacercariae were available to a varying degree at all times of the year. Section V The Use of Nitroxynil in Ovine Fascioliasis The efficiency of nitroxnil administered in the course of an outbreak of fascioliasis was studied. At a dosage rate of 10 mg. per kg. bodyweight, the drug arrested mortality and resulted in rapid improvement of the animals' general condition with the anaemia disappearinh within 3 weeks of treatment. F. hepatica eggs disappeared from the animals' faeces within 5 days of treatment and they were not present again until 9 weeks post-treatment athough is was 13 weeks after treatment before the majority of the lambs had positive faecal egg counts
Dynamics of particle size on inhalation of environmental aerosol and impact on deposition fraction
Inhalation of elevated
levels of particulate air pollution has
been shown to elicit the onset of adverse health effects in humans,
where the magnitude of the response is a product of where in the lung
the particulate dose is delivered. At any point in time during inhalation
the depositional flux of the aerosol is a function of the radius of
the droplet, thus a detailed understanding of the rate and magnitude
of the mass flux of water to the droplet during inhalation is crucial.
In this study, we assess the impact of aerosol hygroscopicity on deposited
dose through the inclusion of a detailed treatment of the mass flux
of water to account for the dynamics of particle size in a modified
version of the standard International Commission on Radiological Protection
(ICRP) whole lung deposition model. The ability to account for the
role of the relative humidity (RH) of the aerosol prior to, and during,
inhalation on the deposition pattern is explored, and found to have
a significant effect on the deposition pattern. The model is verified
by comparison to previously published measurements, and used to demonstrate
that ambient RH affects where in the lung indoor particulate air pollution
is delivered
Predictive and External Validity of a Pre-Market Study to Determine the Most Effective Pictorial Health Warning Label Content for Cigarette Packages
INTRODUCTION: Studies examining cigarette package pictorial health warning label (HWL) content have primarily used designs that do not allow determination of effectiveness after repeated, naturalistic exposure. This research aimed to determine the predictive and external validity of a pre-market evaluation study of pictorial HWLs.
METHODS: Data were analyzed from: (1) a pre-market convenience sample of 544 adult smokers who participated in field experiments in Mexico City before pictorial HWL implementation (September 2010); and (2) a post-market population-based representative sample of 1765 adult smokers in the Mexican administration of the International Tobacco Control Policy Evaluation Survey after pictorial HWL implementation. Participants in both samples rated six HWLs that appeared on cigarette packs, and also ranked HWLs with four different themes. Mixed effects models were estimated for each sample to assess ratings of relative effectiveness for the six HWLs, and to assess which HWL themes were ranked as the most effective.
RESULTS: Pre- and post-market data showed similar relative ratings across the six HWLs, with the least and most effective HWLs consistently differentiated from other HWLs. Models predicting rankings of HWL themes in post-market sample indicated: (1) pictorial HWLs were ranked as more effective than text-only HWLs; (2) HWLs with both graphic and "lived experience" content outperformed symbolic content; and, (3) testimonial content significantly outperformed didactic content. Pre-market data showed a similar pattern of results, but with fewer statistically significant findings.
CONCLUSIONS: The study suggests well-designed pre-market studies can have predictive and external validity, helping regulators select HWL content
Confirmation Via the Continuum-Fitting Method that the Spin of the Black Hole in Cygnus X-1 is Extreme
In Gou et al. (2011), we reported that the black hole primary in the X-ray
binary Cygnus X-1 is a near-extreme Kerr black hole with a spin parameter
a*>0.95(3{\sigma}). We confirm this result while setting a new and more
stringent limit: a*>0.983 at the 3{\sigma}(99.7%) level of confidence. The
earlier work, which was based on an analysis of all three useful spectra that
were then available, was possibly biased by the presence in these spectra of a
relatively strong Compton power-law component: The fraction of the thermal seed
photons scattered into the power law was f_s=23-31%, while the upper limit for
reliable application of the continuum-fitting method is f_s<25%. We have
subsequently obtained six additional spectra of Cygnus X-1 suitable for the
measurement of spin. Five of these spectra are of high quality with f_s in the
range 10% to 19%, a regime where the continuum-fitting method has been shown to
deliver reliable results. Individually, the six spectra give lower limits on
the spin parameter that range from a*>0.95 to a*>0.98, allowing us to
conservatively conclude that the spin of the black hole is a*>0.983
(3{\sigma}).Comment: 14 pages in emulated ApJ format, including 6 figures and 4 tables,
ApJ in press. Discussion on the pileup effect to our spin measurement is
added, including a subsection and a new figure, to reflect the referee's
comments; the conclusions are unchange
Evolution of directional hearing in moths via conversion of bat detection devices to asymmetric pressure gradient receivers
Small animals typically localize sound sources by means of complex internal connections and baffles that effectively increase time or intensity differences between the 2 ears. But some miniature acoustic species achieve directional hearing without such devices, indicating that other mechanisms have evolved. Using 3D laser vibrometry to measure tympanum deflection, we show that female lesser waxmoths (Achroia grisella) can orient toward the 100-kHz male song because each ear functions independently as an asymmetric pressure gradient receiver that responds sharply to high-frequency sound arriving from an azimuth angle 30° contralateral to the animal's midline. We found that females presented with a song stimulus while running on a locomotion compensation sphere follow a trajectory 20° - 40° to the left or right of the stimulus heading but not directly toward it, movement consistent with the tympanum deflections and suggestive of a monaural mechanism of auditory tracking. Moreover, females losing their track typically regain it by auditory scanning â sudden, wide deviations in their heading â and females initially facing away from the stimulus quickly change their general heading toward it, orientation indicating superior ability to resolve the front-rear ambiguity in source location. X-ray CT scans of the moths did not reveal any internal coupling between the 2 ears, confirming for the first time that an acoustic insect can localize a sound source based solely on the distinct features of each ear
Youth self-reported exposure to and perceptions of vaping advertisements:Findings from the 2017 International Tobacco Control Youth Tobacco and Vaping Survey
The Extreme Spin of the Black Hole in Cygnus X-1
The compact primary in the X-ray binary Cygnus X-1 was the first black hole
to be established via dynamical observations. We have recently determined
accurate values for its mass and distance, and for the orbital inclination
angle of the binary. Building on these results, which are based on our favored
(asynchronous) dynamical model, we have measured the radius of the inner edge
of the black hole's accretion disk by fitting its thermal continuum spectrum to
a fully relativistic model of a thin accretion disk. Assuming that the spin
axis of the black hole is aligned with the orbital angular momentum vector, we
have determined that Cygnus X-1 contains a near-extreme Kerr black hole with a
spin parameter a/M>0.95 (3\sigma). For a less probable (synchronous) dynamical
model, we find a/M>0.92 (3\sigma). In our analysis, we include the
uncertainties in black hole mass, orbital inclination angle and distance, and
we also include the uncertainty in the calibration of the absolute flux via the
Crab. These four sources of uncertainty totally dominate the error budget. The
uncertainties introduced by the thin-disk model we employ are particularly
small in this case given the extreme spin of the black hole and the disk's low
luminosity.Comment: Paper III of three papers on Cygnus X-1; 21 pages including 5 figures
and 12 tables, ApJ in press. The paper is significantly restructured; two
further tests of the robustness of our spin measurement are presented, and
our error analysis has been substantially improved; the conclusions are
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