The Financial and Professional Impact of Anterior Cruciate Ligament Injuries in National Football League Athletes.

BACKGROUND: Anterior cruciate ligament (ACL) injuries can have negative consequences on the careers of National Football League (NFL) players, however no study has ever analyzed the financial impact of these injuries in this population. PURPOSE: To quantify the impact of ACL injuries on salary and career length in NFL athletes. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Any player in the NFL suffering an ACL injury from 2010 to 2013 was identified using a comprehensive online search. A database of NFL player salaries was used to conduct a matched cohort analysis comparing ACL-injured players with the rest of the NFL. The main outcomes were the percentage of players remaining in the NFL and mean salary at 1, 2, 3, and 4 years after injury. Cohorts were subdivided based on initial salary: group A,$2,000,000. Mean cumulative earnings were calculated by multiplying the percentage of players remaining in the league by their mean salaries and compounding this each season. RESULTS: NFL athletes suffered 219 ACL injuries from 2010 to 2013. The 7504 other player seasons in the NFL during this time were used as controls. Significantly fewer ACL-injured players than controls remained in the NFL at each time point (P \u3c .05). In group A, significantly less ACL-injured players remained in the NFL at 1 to 3 seasons after injury (P \u3c .05), and in group B, significantly less ACL-injured players remained in the NFL at 1 and 2 seasons after injury (P \u3c .05). There was no significant decrease in group C. Players in groups A and B remaining in the NFL also had a lower mean salary than controls (P \u3c .05 in season 1). The mean cumulative earnings over 4 years for ACL-injured players was$2,070,521 less per player than uninjured controls. CONCLUSION: On average, ACL-injured players earned $2,070,521 less than salary-matched controls over the 4 years after injury. Players initially earning less than$2 million per year have lower mean salaries and are less likely to remain in the league than uninjured controls. The careers of players initially earning over $2 million per year, meanwhile, are not negatively affected. This demonstrates the degree of negative impact these injuries have on the careers of NFL players. It also indicates that a player\u27s standing within the league before injury strongly influences how much an ACL injury will affect his career

INCIDENCE OF COCCIDIA (EIMERIDAE) IN ADULT EWES AND LAMBS ON ST. CROIX

INCIDENCE OF COCCIDIA (EIMERIDAE) IN ADULT EWES AND LAMBS ON ST. CROI

Das virtual capital : an economic perspective on playing online games : Fantastic scarcity and Real-market trades

Massively multiplayer role-playing games (MMORPG) are becoming a popular leisure activity world-wide. MMORPG players have created a new kind of market, one for virtual possessions. Some players will buy and sell virtual goods for real-world money. Many game developers oppose this real-market trade because it threatens the control of their intellectual property. These games are inherently social environments where players group together to fulfill quests and meet goals. The value of virtual possessions is a response to a game world’s fantastic scarcity, where certain virtual goods and activities raise a player’s social rank or further other goals. The game acts like a technological production function that produces virtual goods and capital. Players with high real-world wages will spend less time in games in comparison with low-wage players. Real-market trade allows buyers to shift their real-world wealth into game wealth. However, real-market trade also detracts from the information value of virtual goods, which are act as signals for the amount of time a player has invested and player ability

Helen's >Judgment Of Paris> And Greek Marriage Ritual In Sappho 16

Classic

National Football League Skilled and Unskilled Positions Vary in Opportunity and Yield in Return to Play After an Anterior Cruciate Ligament Injury.

BACKGROUND: Anterior cruciate ligament (ACL) injuries pose a significant risk to the careers of players in the National Football League (NFL). The relationships between draft round and position on return to play (RTP) among NFL players are not well understood, and the ability to return to preinjury performance levels remains unknown for most positions. PURPOSE: To test for differences in RTP rates and changes in performance after an ACL injury by position and draft round. We hypothesized that skilled positions would return at a lower rate compared to unskilled positions. We further hypothesized that early draft-round status would relate to a greater rate of RTP and that skilled positions and a lower draft round would correlate with decreased performance for players who return to sport. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: Utilizing a previously established database of publicly available information regarding ACL tears among NFL players, athletes with ACL tears occurring between the 2010 and 2013 seasons were identified. Generalized linear models and Kaplan-Meier time-to-event models were used to test the study hypotheses. RESULTS: The overall RTP rate was 61.7%, with skilled players and unskilled players returning at rates of 64.1% and 60.4%, respectively (P = .74). Early draft-round players and unskilled late draft-round players had greater rates of RTP compared to skilled late draft-round players and both unskilled and skilled undrafted free agents (UDFAs). Skilled early draft-round players constituted the only cohort that played significantly fewer games after an injury. Unskilled UDFAs constituted the only cohort to show a significant increase in the number of games started and ratio of games started to games played, starting more games in which they played, after an injury. CONCLUSION: Early draft-round and unskilled players were more likely to return compared to their later draft-round and skilled peers. Skilled early draft-round players, who displayed relatively high rates of RTP, constituted the only cohort to show a decline in performance. Unskilled UDFAs, who exhibited relatively low rates of RTP, constituted the only cohort to show an increase in performance. The significant effect of draft round and position type on RTP may be caused by a combination of differences in talent levels and in opportunities given to returning to play

Anterior Cruciate Ligament Injuries in National Football League Athletes From 2010 to 2013: A Descriptive Epidemiology Study.

BACKGROUND: There is a high incidence of anterior cruciate ligament (ACL) injuries among National Football League (NFL) athletes; however, the incidence of reinjury in this population is unknown. PURPOSE: This retrospective epidemiological study analyzed all publicly disclosed ACL tears occurring in NFL players between 2010 and 2013 to characterize injury trends and determine the incidence of reinjury. STUDY DESIGN: Descriptive epidemiological study. METHODS: A comprehensive online search identified any NFL player who had suffered an ACL injury from 2010 to 2013. Position, playing surface, activity, and date were recorded. Each player was researched for any history of previous ACL injury. The NFL games database from USA Today was used to determine the incidence of ACL injuries on artificial turf and grass fields. Databases from Pro Football Focus and Pro Football Reference were used to determine the injury rate for each position. RESULTS: NFL players suffered 219 ACL injuries between 2010 and 2013. Forty players (18.3%) had a history of previous ACL injury, with 27 (12.3%) retears and 16 (7.3%) tears contralateral to a previous ACL injury. Five players (2.28%) suffered their third ACL tear. Receivers (wide receivers and tight ends) and backs (linebackers, fullbacks, and halfbacks) had significantly greater injury risk than the rest of the NFL players, while perimeter linemen (defensive ends and offensive tackles) had significantly lower injury risk than the rest of the players. Interior linemen (offensive guards, centers, and defensive tackles) had significantly greater injury risk compared with perimeter linemen. ACL injury rates per team games played were 0.050 for grass and 0.053 for turf fields (P \u3e .05). CONCLUSION: In this retrospective epidemiological study of ACL tears in NFL players, retears and ACL tears contralateral to a previously torn ACL constituted a substantial portion (18.3%) of total ACL injuries. The significant majority of ACL injuries in players with a history of previous ACL injury were retears. Skilled offensive players and linebackers had the greatest injury risk, and significantly more ACL tears occurred among interior linemen than perimeter linemen. The month of August had the highest incidence of ACL injuries, probably because of expanded roster sizes at that point in the NFL season

Interactions Between Moderate- and Long-Period Giant Planets: Scattering Experiments for Systems in Isolation and with Stellar Flybys

The chance that a planetary system will interact with another member of its host star's nascent cluster would be greatly increased if gas giant planets form in situ on wide orbits. In this paper, we explore the outcomes of planet-planet scattering for a distribution of multiplanet systems that all have one of the planets on an initial orbit of 100 AU. The scattering experiments are run with and without stellar flybys. We convolve the outcomes with distributions for protoplanetary disk and stellar cluster sizes to generalize the results where possible. We find that the frequencies of large mutual inclinations and high eccentricities are sensitive to the number of planets in a system, but not strongly to stellar flybys. However, flybys do play a role in changing the low and moderate portions of the mutual inclination distributions, and erase dynamically cold initial conditions on average. Wide-orbit planets can be mixed throughout the planetary system, and in some cases, can potentially become hot Jupiters, which we demonstrate using scattering experiments that include a tidal damping model. If planets form on wide orbits in situ, then there will be discernible differences in the proper motion distributions of a sample of wide-orbit planets compared with a pure scattering formation mechanism. Stellar flybys can enhance the frequency of ejections in planetary systems, but auto-ionization is likely to remain the dominant source of free-floating planets.Comment: Accepted for publication by Ap

Formation, Survival, and Detectability of Planets Beyond 100 AU

Direct imaging searches have begun to detect planetary and brown dwarf companions and to place constraints on the presence of giant planets at large separations from their host star. This work helps to motivate such planet searches by predicting a population of young giant planets that could be detectable by direct imaging campaigns. Both the classical core accretion and the gravitational instability model for planet formation are hard-pressed to form long-period planets in situ. Here, we show that dynamical instabilities among planetary systems that originally formed multiple giant planets much closer to the host star could produce a population of giant planets at large (~100 AU - 100000 AU) separations. We estimate the limits within which these planets may survive, quantify the efficiency of gravitational scattering into both stable and unstable wide orbits, and demonstrate that population analyses must take into account the age of the system. We predict that planet scattering creates a population of detectable giant planets on wide orbits that decreases in number on timescales of ~10 Myr. We demonstrate that several members of such populations should be detectable with current technology, quantify the prospects for future instruments, and suggest how they could place interesting constraints on planet formation models.Comment: 13 pages (emulateapj format), 10 figures, accepted for publication in Ap

Thermal Infrared MMTAO Observations of the HR 8799 Planetary System

We present direct imaging observations at wavelengths of 3.3, 3.8 (L',band), and 4.8 (M band) microns, for the planetary system surrounding HR 8799. All three planets are detected at L'. The c and d component are detected at 3.3 microns, and upper limits are derived from the M band observations. These observations provide useful constraints on warm giant planet atmospheres. We discuss the current age constraints on the HR 8799 system, and show that several potential co-eval objects can be excluded from being co-moving with the star. Comparison of the photometry is made to models for giant planet atmospheres. Models which include non-equilibrium chemistry provide a reasonable match to the colors of c and d. From the observed colors in the thermal infrared we estimate T_eff < 960 K for b, and T_eff=1300 and 1170 K for c and d, respectively. This provides an independent check on the effective temperatures and thus masses of the objects from the Marois 2008 results.Comment: 16 pages, 6 figures, accepted to Ap

The Formation Mechanism of Gas Giants on Wide Orbits

The recent discoveries of massive planets on ultra-wide orbits of HR 8799 (Marois et al. 2008) and Fomalhaut (Kalas et al. 2008) present a new challenge for planet formation theorists. Our goal is to figure out which of three giant planet formation mechanisms--core accretion (with or without migration), scattering from the inner disk, or gravitational instability--could be responsible for Fomalhaut b, HR 8799 b, c and d, and similar planets discovered in the future. This paper presents the results of numerical experiments comparing the long-period planet formation efficiency of each possible mechanism in model A star, G star and M star disks. First, a simple core accretion simulation shows that planet cores forming beyond 35 AU cannot reach critical mass, even under the most favorable conditions one can construct. Second, a set of N-body simulations demonstrates that planet-planet scattering does not create stable, wide-orbit systems such as HR 8799. Finally, a linear stability analysis verifies previous work showing that global spiral instabilities naturally arise in high-mass disks. We conclude that massive gas giants on stable orbits with semimajor axes greater than 35 AU form by gravitational instability in the disk. We recommend that observers examine the planet detection rate as a function of stellar age, controlling for planet dimming with time. If planet detection rate is found to be independent of stellar age, it would confirm our prediction that gravitational instability is the dominant mode of producing detectable planets on wide orbits. We also predict that the occurrence ratio of long-period to short-period gas giants should be highest for M dwarfs due to the inefficiency of core accretion and the expected small fragment mass in their disks.Comment: Accepted for publication in the Astrophysical Journal. 14 pages, including 3 figures and 1 tabl