Tuesday, June 27, 2017

Slow motion makes football referees more likely to give a red card


Video assistant refereeing in football has to be used with caution. Researchers at KU Leuven (University of Leuven), Belgium, have shown that refs are more likely to give red when they see a foul committed in slow motion, even when a yellow card is more justifiable. This is because fouls viewed in slow motion appear to be more serious.

Football referees and the decisions they make are the subject of very heated debates in the canteen, at the kitchen table, and in the TV studio. Football fans keep a vigilant eye on their every move and decision. These high demands have led to professionalization: more and more elite referees are full-time professionals and follow specific training programmes. Another consequence are the experiments with video assistant refereeing, whereby video assistant referees (VARs) support the referees and check the accuracy of decisions by replaying game situations in real time and in slow motion.

Under the supervision of Professor Wim Helsen, sport scientist at KU Leuven and referee training expert, Jochim Spitz wrote a PhD on the impact of slow motion videos on football referees' perception and decision-making process. He found that the effect of slow motion greatly depends on the type of decision that the referee has to make, as well as on the situation.

For technical decisions on whether or not a foul was committed, watching slow motion videos only improved the accuracy in corner kick situations. "Corner kicks always involve many players, so slow motion may help spot the right fouls in the commotion," Spitz explains.

But for disciplinary sanctions on whether or not to give a card - and if so, which one - slow motion had a significant impact on the decision-making process. "We asked 88 European referees to take a disciplinary sanction for 60 game situations - yellow, red, or no card at all. They had to assess half of the situations after watching a video in real time and the other half based on slow motion videos. For each of these situations, a panel of UEFA experts had given us a benchmark decision. We found that referees judge more harshly when they are exposed to fouls in slow motion. In situations for which the benchmark decision was a yellow card, 20% percent of the referees gave red after watching the video in slow motion. In real time this was only 10%."

"The reason is that fouls viewed in slow motion appear to be more serious" Professor Werner Helsen explains. "This has major implications for the adequate use of video technology in football. Based on the results of this study, the International Football Association Board (IFAB) has already issued guidelines for the use of slow motion videos: they can only be used to determine whether a foul was committed inside or outside the penalty area, or to locate the impact of a tackle on the opponent's body."


Thursday, April 6, 2017

Red Sox to eke out American League East win over Blue Jays

NJIT mathematician's 2017 Major League Baseball projections
 
Red Sox to eke out American League East win over Blue Jays while Indians and Astros to win American League Central and West Handily; Nationals, Cubs and Dodgers to repeat as National League division winners

After projecting 8 of the 10 Major League Baseball post-season teams in 2016 and correctly claiming that the St. Louis Cardinals would just miss making the playoffs, New Jersey Institute of Technology (NJIT) Mathematical Sciences Professor and Associate Dean Bruce Bukiet has published his model's projections of how the standings should look at the end of Major League Baseball's regular season in 2017. This is the 20th year that Bukiet has applied mathematical analysis to compute the number of regular season games each Major League Baseball team should win. Though his expertise is in mathematical modeling (rather than baseball), his projections have consistently compared well with those of so-called experts.

The numbers indicate that while his favorite team, the New York Mets (92 wins) should make the playoffs, the Washington Nationals (97 wins) should repeat as winners of the National League East. The World Champion Chicago Cubs and Los Angeles Dodgers should repeat as winner of the National League Central and West Divisions with 104 wins each to lead the Major Leagues. The San Francisco Giants (95 wins) should be the fifth National League post-season team. The same five teams (correctly called by Bukiet) made the post-season in 2016 and once again the St. Louis Cardinals (88 wins) should be the best team that doesn't make the post-season -- though it shouldn't be so close this time.

In the American League, Bukiet's model has the Boston Red Sox (91 wins) and American League pennant Cleveland Indians (99 wins -- best in the American league) repeating as division winners in the East and Central divisions. Bukiet once again calls for the Houston Astros (94 wins) to win the American League West. (This was one of the two projections that did not pan out for Bukiet last year, with the Texas Rangers winning that division -- the Orioles made the post-season and not the Rays as the model projected). The model calls for the Toronto Blue Jays (90 wins) and the Detroit Tigers (86 wins) to be the American League Wild Card teams. The Texas Rangers, Seattle Mariners and New York Yankees should all be 6 games behind the Tigers and this not make the post-season.

At the other end of the spectrum, the San Diego Padres (53 wins) should replace the Minnesota Twins as the team with the worst record in baseball. The Padres should win just over half as many games as the division winning Dodgers, ending up 51 games out of first place. The White Sox (64 wins) should win the least games in the American League.

Bukiet makes these projections to demonstrate and promote the power of math. He wants to show young people that math can be fun, that it can be applied to improve one's understanding of many aspects of life and that if you love mathematics, it can be a great college major and lead to a satisfying career.

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Bukiet bases his projections on a mathematical model he started developing in the late 1980s. He has made various revisions over the years. His results have been noted in many publications and he has been predictions champ at baseballphd.net several times. See more results for his baseball modeling, including the projected wins for each of the 30 Major League Baseball teams, at http://web.njit.edu/~bukiet/baseball/baseball.html and at http://www.egrandslam.com.

Tuesday, March 14, 2017

Study identifies modifiable risk factors for elbow injuries in baseball pitchers


Hospital for Special Surgery study findings build foundation for future injury prevention studies
HOSPITAL FOR SPECIAL SURGERY
Elbow injuries continue to be on the rise in baseball players, especially pitchers, yet little is known about the actual variables that influence these injuries.
While elbow varus torque is already linked to ulnar collateral ligament (UCL) injuries, the connection between certain pitching movements and elbow varus torque is unknown.
A study from Hospital for Special Surgery set out to find the relationship between elbow varus torque and the following variables: arm slot, arm speed and shoulder rotation. The prospective cohort study looked at 81 professional pitchers (either in the Major or Minor Leagues) who took 81,999 throws while wearing a Motus baseball sleeve. The study was presented at the American Academy of Orthopaedic Surgeons Annual Meeting on March 14 in San Diego.
These were a combination of throws that were evaluated in real settings, such as structured long tosses and live game play, as opposed to in a laboratory, like previous studies. This was the largest analysis of throwing biomechanics to date.
"Obtaining this comprehensive, individualized analysis of on-field throwing activity was made possible by technological advancements that give us the ability to accurately measure body motions outside the lab," said Joshua Dines, MD, sports medicine surgeon at HSS and primary investigator. "Capturing data during the pitchers' normal activities provided us with robust, baseline biomechanical performance metrics."
The study found that arm slot, arm speed and shoulder rotation all have a significant relationship with elbow varus torque. There was a 1-nm increase in elbow varus torque associated with a 13 degree decrease in arm slot, 116% increase in arm speed and 8 degree increase in shoulder rotation.
Increased arm speed and shoulder rotation were found to be associated with increased elbow stress as well as decreased arm slot. Height and weight were also positively correlated with elbow varus torque.
"Now that we know these modifiable risk factors, we have a foundation to develop evidence-based rehabilitation programs. Additionally, these findings can be utilized to prevent injury and help to identify potential pitchers at risk," said David Altchek, MD, sports medicine surgeon at HSS.

Wednesday, February 15, 2017

Evidence of brain damage found in former soccer players


Evidence of chronic traumatic encephalopathy (CTE), a potential cause of dementia caused by repeated blows to the head, has been found in the brains of former soccer players
UNIVERSITY COLLEGE LONDON
Evidence of chronic traumatic encephalopathy (CTE), a potential cause of dementia caused by repeated blows to the head, has been found in the brains of former association football (soccer) players examined at the UCL Queen Square Brain Bank.
The study, funded by The Drake Foundation and published in the journal Acta Neuropathologica, looked at 14 retired footballers with dementia who were referred to the Old Age Psychiatry Service in Swansea, Wales, between 1980 and 2010. Permission from their next-of-kin was provided to perform post-mortem examinations, which were carried out in six ex-players. Post-mortem analysis of the brain was carried out by researchers from UCL and the National Hospital for Neurology and Neurosurgery.
The team identified CTE pathology in four of the six brains examined, and all six also had signs of Alzheimer's disease. The rate of CTE identified in the footballers' brains exceeds the 12% average background rate of CTE found in a previous survey of 268 brains of an unselected population at the Queen Square Brain Bank. Like Alzheimer's disease, CTE can cause dementia and they are both characterised by a build-up of abnormal tau protein in the brain, but CTE causes tau to accumulate in a distinctive pattern. Previous studies have found evidence of CTE in the brains of contact sports players, most notably boxers and American football players. Footballers are exposed to repetitive blows to the head from heading the ball and from head-to-player collisions. However, football is unique compared with boxing and American football in that blows to the head are commonly more minor and footballers are less likely to experience significant neurological symptoms or loss of consciousness.
"This is the first time CTE has been confirmed in a group of retired footballers," explains lead author Dr Helen Ling (UCL Institute of Neurology), senior research associate at the Department of Molecular Neuroscience and neurologist. "Our findings of CTE in retired footballers suggest a potential link between playing football and the development of degenerative brain pathologies in later life. However, it is important to note that we only studied a small number of retired footballers with dementia and that we still do not know how common dementia is among footballers." 
"All of the players whose brain autopsies showed signs of CTE also had Alzheimer's pathology, but the relationship between the two diseases remains unclear. Both diseases involve a build-up of an insoluble form of tau protein in the brain. However, in CTE tau tends to accumulate around blood vessels and at the depths of the sulci - the grooves in the brain's surface - which helps to differentiate CTE from Alzheimer's pathology under the microscope. Previous studies have shown that the risk of Alzheimer's disease is increased in people with previous head injuries. On the other hand, the risk of dementia is also increased with age and we don't know if these footballers would have developed Alzheimer's disease anyway if they hadn't played football. The most pressing research question is therefore to find out if dementia is more common in footballers than in the normal population."
The ex-footballers monitored in the study all started playing football and heading the ball in their childhood or early teens and continued to play regularly for an average of 26 years. Only six reported concussion with loss of consciousness while playing football, limiting to a single episode each during their playing career. The earliest symptoms of dementia started while they were in their 60s and they lived for an average of 10 years after symptoms began. Twelve out of 14 of them eventually died of advanced dementia. 
"We do not yet know exactly what causes CTE in footballers or how significant the risk is," says co-lead author Professor Huw Morris (UCL Institute of Neurology), Professor of Clinical Neuroscience and honorary consultant neurologist at the Royal Free Hospital and National Hospital for Neurology and Neurosurgery. "Major head injuries in football are more commonly caused by player collisions rather than heading the ball. The average footballer heads the ball thousands of times throughout their career, but this seldom causes noticeable neurological symptoms. More research is now urgently needed to determine the risks associated with playing football so that any necessary protective measures can be put in place to minimise potential long term damage."
"Of course, any kind of physical activity will be associated with health risks and benefits and it is well-established that playing sports can significantly improve physical and mental health."
Of the 14 footballers included in the study, 13 were former professionals and one was a committed amateur who played every season for 23 years. They were all diagnosed with dementia between 1980 and 2010 and referred to the Old Age Psychiatry Service in Swansea run by consultant psychiatrist Dr Don Williams. He monitored these ex-footballers regularly and collected demographic and clinical data, playing and concussion history from their close relatives. Dr Williams says:
"In 1980 the son of a man with advanced dementia asked me if his father's condition had been caused by heading the ball for many years as a powerful centre-half. As the brain is a very fragile organ, well protected within the skull, this was a constructive suggestion. As a result I looked out for men with dementia and a significant history of playing soccer, followed them up and where possible arranged for post-mortem studies to be carried out. The results suggest that heading the ball over many years, a form of repetitive sub-concussive head injury, can result in the development of CTE and dementia. Thus the original suggestion has been shown to be of merit and worthy of further investigation."
The research was funded by UK-based not-for-profit The Drake Foundation. Chief Scientific Officer Velicia Bachtiar, says: "The Drake Foundation is proud to have funded this important research, which highlights the need for future work to improve our understanding of sports-related head injuries and their long-term implications."

Thursday, February 9, 2017

Footballing success in the young can be measured in the brain


KAROLINSKA INSTITUTET


The working memory and other cognitive functions in children and young people can be associated with how successful they are on the football pitch, a new study from Karolinska Institutet, Sweden, shows. Football clubs that focus too much on physical attributes therefore risk overlooking future stars.
Physical attributes such as size, fitness and strength in combination with ball control have long been considered critical factors in the hunt for new football talent. The third, slightly elusive factor of "game intelligence" -- making the best play under the circumstances-- has been difficult to measure. In 2012, researchers at Karolinska Institutet provided a possible scientific explanation for the phenomenon, and showed that the so-termed "executive cognitive functions" in adult players could be associated with their success on the pitch. In a new study, which is published in the scientific journal PLOS ONE, they show that cognitive faculties can be similarly quantified and linked to how well children and young people do in the game.
"This is interesting since football clubs focus heavily on the size and strength of young players," says study leader Predrag Petrovic, at Karolinska Institutet's Department of Clinical Neuroscience. "Young players who have still to reach full physical development rarely get a chance to be picked as potential elite players, which means that teams risk missing out on a new Iniesta or Xavi."
Executive functions are special control functions in the brain that allow us to adapt to an environment in a perpetual state of change. They include creative thinking in order to quickly switch strategy, find new, effective solutions and repress erroneous impulses. The functions are dependent on the brain's frontal lobes, which continue to develop until the age of 25.
For this present study, the researchers measured certain executive functions in 30 elite footballers aged between 12 and 19, and then cross-referenced the results with the number of goals they scored during two years. The metrics were taken in part using the same standardised tests used in healthcare. Strong results for several executive functions were found to be associated with success on the pitch, even after controlling for other factors that could conceivably affect performance. The clearest link was seen for simpler forms of executive function, such as working memory, which develops relatively early in life.
"This was expected since cognitive function is less developed in young people than it is in adults, which is probably reflected in how young people play, with fewer passes that lead to goals," says Predrag Petrovic.
The young elite players also performed significantly better than the average population in the same age group on several tests of executive function. Whether these faculties are inherited or can be trained remains the object of future research, as does the importance of the different executive functions for the various positions on the field.
"We think that the players' positions on the pitch are linked to different cognitive profiles," continues Dr Petrovic. "I can imagine that trainers will start to use cognitive tests more and more, both to find talented newcomers and to judge the position they should play in."

Wednesday, February 1, 2017

Soccer ball heading may commonly cause concussion symptoms


ALBERT EINSTEIN COLLEGE OF MEDICINE
Frequent soccer ball heading is a common and under recognized cause of concussion symptoms, according to a study of amateur players led by Albert Einstein College of Medicine researchers. The findings run counter to earlier soccer studies suggesting concussion injuries mainly result from inadvertent head impacts, such as collisions with other players or a goalpost. The study was published online today in Neurology®, the medical journal of the American Academy of Neurology.
"The prevailing wisdom is that routine heading in soccer is innocuous and we need only worry about players when they have unintentional head collisions," says study leader Michael L. Lipton, M.D., Ph.D., professor of radiology and of psychiatry and behavioral sciences at Einstein and director of MRI Services at Montefiore. "But our study suggests that you don't need an overt collision to warrant this type of concern. Many players who head the ball frequently are experiencing classic concussion symptoms such as headache, confusion, and dizziness during games and practice, even though they are not actually diagnosed with concussion. Concussion sufferers should avoid additional collisions or head impacts during the following days or weeks, when their risk of incurring a second concussion is extremely high. Because these injuries go unrecognized and unmanaged, there may be important clinical consequences for the short and long term."
Studies clearly show that single or repeated concussion causes neurologic problems. But little is known about the effects of frequent but lesser impacts, such as those experienced while heading a soccer ball. Some research, notably a recent study of adolescent players published in JAMA Pediatrics, suggest that heading is not a common cause of concussion. "However, these studies did not actually measure heading, and thus they were unable to separate the relative contributions of intentional and unintentional head impacts," says Dr. Lipton. 
In the current study, a part of the Einstein Soccer Study, Dr. Lipton and his colleagues asked 222 adult amateur soccer players (80 percent men, ages 18 to 55) to fill out online questionnaires on their soccer-related activities during the previous two weeks, including details about heading and other unintentional head impacts and any resulting headaches, pain and dizziness as well as more severe symptoms, such as feeling dazed, needing medical attention, and becoming unconscious. Some of the 222 players filled out questionnaires for more than a single two-week span, resulting in a total of 470 questionnaires during a nine-month period in 2013-2014.
Approximately 35 percent of the participants reported one unintentional head impact, and 16 percent reported more than one such impact. The median number of headings during the two-week reporting period for all respondents was 40.5. Twenty percent of the participants reported experiencing moderate-to-very severe concussion symptoms, with 18 percent reporting severe and 7 percent very severe symptoms. Although these symptoms were more strongly connected with unintentional head impacts, heading was shown to be an independent risk factor for concussion symptoms.
"This finding is consistent with one of our previous studies, where 30 percent of soccer players who'd had more than 1,000 headings per year had a higher risk of microstructural changes in the brain's white matter, typical of traumatic brain injury, and worse cognitive performance," says Dr. Lipton
In the new study, players who headed the most were the most susceptible to concussion. "The extent to which lesser degrees of exposure to heading lead to cumulative injury over time is not known and deserves further study," Dr. Lipton says. "Our findings certainly indicate that heading is more than just a 'sub-concussive' impact, and that heading-related concussions are common. We need to give people who have these injuries proper care and make efforts to prevent multiple head impacts, which are particularly dangerous."

Tuesday, January 24, 2017

Jet lag impairs performance of Major League Baseball players



A new Northwestern University study of how jet lag affects MLB players traveling across just a few time zones finds that when people, in this case Major League Baseball players, travel in a way that misaligns their internal 24-hour clock with the natural environment and its cycle of sunlight, they suffer negative consequences.

"Jet lag does impair the performance of Major League Baseball players," said Dr. Ravi Allada, a circadian rhythms expert who led the study. "The negative effects of jet lag we found are subtle, but they are detectable and significant. And they happen on both offense and defense and for both home and away teams, often in surprising ways."

In a study of data spanning 20 years and including more than 40,000 games, the researchers identified these effects of jet lag on player and team performance:
  • The offense of jet-lagged home teams is much more affected than that of jet-lagged away teams. Surprisingly, in terms of offensive performance, jet lag from eastward travel had significant negative effects on home teams (after returning from a road trip) and much less of an effect on away teams.
  • Negative effects on offense are related to base running. The negative effects on the home team's offense were related to base running, such as stolen bases, number of doubles and triples, and hitting into more double plays.
  • Both home and away teams suffer on defense, specifically by giving up more home runs. With defensive performance, strong effects of eastward jet lag were found for both home and away teams, primarily with jet-lagged pitchers allowing more home runs. "The effects are sufficiently large to erase the home field advantage," Allada said. Besides home runs allowed, few other effects were seen on pitching or defense.
  • There is a difference between traveling east and traveling west. Most significant jet-lag effects were generally stronger for eastward than westward travel. "This is a strong argument that the effect is due to the circadian clock, not the travel itself," Allada said.
The study, "How Jet Lag Impairs Major League Baseball Performance," will be published the week of Jan. 23 in the journal Proceedings of the National Academy of Sciences (PNAS).

Allada and his team, Alex Song (first author) and Thomas Severini, used an unprecedented amount of MLB data (from 1992 to 2011), which gave the researchers the statistical power to identify the effects of jet lag on offensive and defensive performance metrics. The researchers considered if teams were traveling east or west; if the team was home or away; and the team itself.

They also looked at the number of hours players would be jet-lagged, based on the number of time zones traveled across, to determine which games were "jet-lag games" and which were not. (The human body clock can roughly shift about an hour each day as it synchronizes to the new environment.) If players were shifted two or three hours from their internal clocks, the researchers defined them as jet-lagged.

What does all this data analysis mean going forward? With MLB spring training less than a month away, Allada has some advice based on his research.

"If I were a baseball manager and my team was traveling across time zones -- either to home or away -- I would send my first starting pitcher a day or two ahead, so he could adjust his clock to the local environment," Allada said.

Allada provides an example from the 2016 National League Championship Series illustrating the potential impact of jet lag on player performance. In game 2, Los Angeles Dodgers' ace Clayton Kershaw shut out the Chicago Cubs, giving up only two hits, but game 6 was a different story.
"For game 6, the teams had returned to Chicago from LA, and this time the Cubs scored five runs off of Kershaw, including two home runs," Allada said. "While it's speculation, our research would suggest that jet lag was a contributing factor in Kershaw's performance."

Wednesday, January 18, 2017

More sprints in top-class football necessitates new and individualized training routines


Today's top-class football is characterised by more short sprints than in the past. In English Premier League, high-intensity running has increased by 50% in the last 10 years, presenting new challenges to the players in terms of fatigue resistance and ability to recover quickly. The change has also resulted in greater variation in the tempo of matches, and this new pattern calls for revised training routines. This is the conclusion of new research from the University of Gothenburg and the University of Southern Denmark.
The study in question is based on an extensive amount of data. A research team, consisting of Dan Fransson and Magni Mohr, exercise physiology researchers at the Department of Food and Nutrition, and Sport Science, University of Gothenburg, and Professor Peter Krustrup from the University of Southern Denmark, watched 62 football matches played 2010-2012 and made 1 105 observations of 473 players from 24 different Premier League teams.
The results show that, compared with in the past, modern top-class football is characterised by more high-intensity sprints followed by a substantially lower tempo. Repeated bouts of high-intensity running for 1-5 minutes are followed by a historically low intensity for up to 5 minutes. Thus, a player's activity level during a match tends to alternate between two extremes, compared with the traditionally more steady match tempo.
Training Should Be Adapted to the New Pattern
The analysis points to significant differences in fatigue and recovery patterns among players. Some players can exhibit four times as much high-intensity running as others in one and the same match.
'This indicates that in order for players to maximise their potential and avoid injuries, they need more individualised training depending on position played. All players shouldn't train in the same way,' says Fransson.
Central defenders stand out from the other playing positions. These are the only players whose running did not decrease after the most intense 1-2-minute periods.
'The reason for this is simply that central defenders face the lowest demands of all players except goalkeepers when it comes to high-intensity running. They have the longest recovery periods between the intense phases of a football match,' says Fransson.


Could better eye training help reduce concussion in women's soccer?


With the ever-growing popularity of women's soccer, attention to sports-related concussions is also a growing concern, as the act of heading the ball is thought to contribute to increased incidence of concussion. 
"Current evidence shows that high school female soccer players incur a higher concussion rate than males," says Joe Clark, PhD, professor in the Department of Neurology and Rehabilitation Medicine at the University of Cincinnati College of Medicine. "While this is often attributed to gender differences in physical build or neck muscle strength, our study suggested that there might be other behaviors such as field awareness that are contributing factors that result in these higher concussion rates."
Researchers working with Clark observed that in photographs of female soccer players during play, the players often had their eyes closed while heading the ball. They wanted to quantify whether female athletes closed their eyes more frequently than male counterparts, as a first step toward determining if less visual awareness might expose players to a higher risk of injury. Their results of the first part of this study are have been published in the online version of Medical Hypotheses.
Through an analysis of Google images of soccer headers by both male and female players in active game play, 100 images of each gender were reviewed and categorized. Some images showed more than one athlete participating in the header, what some people may call a 50-50 ball.
Of 170 females identified in the photos, 90.6 percent of them were shown to have their eyes closed during play. By comparison, 79 percent of male players had their eyes closed, of the 170 male athletes evaluated in the photos. 
These findings indicated that female players were more likely to close their eyes at the act of heading the ball, versus males. Vision training methods in other concussion-prone sports like football work to train the athletes to use visual tactics to be aware of the ball and aware of other players prior to a hit something the researchers refer to as "eye discipline." 
It is felt that better eye discipline may account for the difference in concussion rates between males and females. "In other studies, vision training has successfully reduced the rates of concussion in college football athletes; overall lack of visual awareness in a contact sport may increase the risks of concussion. Therefore vision training and better eye discipline may decrease concussion rates." 
Clark, who works with high school and college-level athletes on vision training techniques to improve their awareness in avoiding hits on the field, says that with practice, athletes can learn to play safer. "The startle reflex, or blinking or closing one's eyes upon a perceived risk, can be suppressed through training and coaching. So it is possible that training to improve eye discipline and maintain control of ball handling, may help mitigate concussions in soccer players heading the ball," he says.
Hagar Elgendy, a medical student at the UC College of Medicine, and a co-author of the study, has been involved with the sports medicine research at UC for the past few years. "Concussion in sport has gained much attention recently. It was exciting and interesting to be involved in this project and to propose a hypothesis for the greater concussion incidence in the high school athletic setting for females over males." Elgendy, along with her sister, Hanna Elgendy, worked to obtain and analyze the Google images for the study.
Clark says, "We hope to follow up with larger future studies as to whether eyes closed upon impact correlate with higher rates of concussion, to validate this hypothesis."