Fun Time Chatting Sabbatical Research!

I thoroughly enjoyed giving the first Science Gang talk at my college yesterday.  Speaking about my research is a lot of fun for me.  My talk's theme was friction, a topic that included not only my sabbatical research, but elements of friction existing between people and places.  For example, political divisions are so wide these days.  It seems as if some of the friction between people on different sides of the political spectrum could be alleviated by getting together and engaging in civil conversations.  Instead so many of us have ensconced ourselves with people who agree with us, websites that share our opinions, and even online searches that filter based on our preferences.  It wasn't hard during our travels abroad to notice lots of different types of friction between people, both in today's world and in the past.

Moving from friction between people to my friction research was a welcome transition.  Many in my audience had not been exposed to much physics, so I kept the friction science light.  The photo below shows me discussing some friction basics (click on the image for a larger view).

The room was a dark and a colleague was kind enough to grab a photo with a cell phone.  I was happy to receive a photo.  I got some great questions after I finished, giving me more to ponder.  There is always more to learn!

Talk on Monday the 19th

I will give a public lecture on Monday, 19 September at 4:30 pm here at Lynchburg College.  My talk will be the first Science Gang lecture of the current academic year.  It will be held in Hopwood Auditorium.  A flyer for my talk appears below (click on the image for a larger view).

I will discuss the research work I did at the University of Sheffield in England during my sabbatical.  Topics include friction between tennis shoe and hard court, soccer aerodynamics, and Tour de France modeling.  Because friction was such an important part of my research, I'll make connections to other types of frictions seen during our travels throughout Europe.  Check out my talk if you find yourself in the Lynchburg area on Monday the 19th.

How fast could YOU swim Burj Khalifa?

Getting my family moved back to the US from England and preparing for a new semester at Lynchburg College have greatly reduced the amount of time that I've had available for watching the Rio Olympics.  I certainly won't be able to write blog posts at the rate I did during the 2012 Olympics in London (click here for a summary of what I wrote back then).  Despite how busy life for me is right now, I've been thrilled and moved watching the majesty of Simone Biles (born on Pi Day in 1997!) and the rest of the US women's gymnastics team, the continued dominance of athletes like Usain Bolt and Michael Phelps, and the emotional win for Thiago Braz da Silva in the pole vault.  But one event really took my breath away, and that was the women's 800-m freestyle.

Katie Ledecky (born on Saint Patrick's Day in 1997, just three days after Simone Biles!) so dominated that event that I wondered if she would finish, hop out of the pool, and then enjoy a cool drink while watching the rest of the field finish.  She shattered the world record, setting the new standard for excellence at 8:04.79, which was more than 11 s quicker than silver medalist Jazmin Carlin of Great Britain.  Ledecky's average speed was 1.65 m/s or 5.94 kph or 3.69 mph.  Consider that a typical walking speed is about 5 kph (3 mph), which means that Ledecky swam faster than someone walking over a distance of 0.8 km (0.5 mi).  I'm not in terrible shape, but swimming a half mile is a fairly daunting thought for me.  Doing so in anything close to eight minutes would be impossible for me!

How about more perspective on what Ledecky did?  The tallest building in the world is Dubai's Burj Khalifa.  From ground to tip, the building stands 829.8 m (2722 ft) tall.  Elevators in that building are incredibly fast, with speeds of 10 m/s (36 kph or 22 mph).  That's Usain Bolt speed, but Bolt can only sustain that average speed for 100 m or so.  I'm impressed that Bolt could keep up with Burj Khalifa's elevators for about 20 floors.  But I'm equally impressed that Ledecky could swim the entire length of Burj Khalifa in about 8.5 minutes.  Thinking "outside the pool" sometimes helps me gain better perspective.

Back in the US!

I suppose this is the last of my sabbatical journal entries on this blog.  We are back in the US after my wonderful sabbatical year at the University of Sheffield.  The last week in Sheffield was a lot of fun.  My daughters were out of school and got to spend time with their friends.  Both my girls made me proud, not only with their schoolwork, but with their ability to acclimate themselves to living in Europe for a year.  They missed their Virginia friends and will be glad to see them in a few days, but they made good friends in Sheffield that they'll surely miss in the coming weeks.

My research work advanced significantly during my sabbatical.  I learned a great deal about friction, especially the interaction between rubber treads and hard courts.  Teaming up with colleagues in the Department of Mechanical Engineering at the University of Sheffield gave me the opportunity to further my understanding of friction and publish our novel studies.  We still have more work to do!  Working with Matt Carré during my two sabbatical years has been a joy.  I can't recommend highly enough collaborating with someone outside your area of expertise.  My approach is that of a physicist; Matt's is that of an engineer.  Our different ways of seeing problems and tackling solutions led to very fruitful research efforts.  Working with his students and postdocs was rewarding, too.  Young and fresh eyes view problems in interesting ways, and I don't mind learning from someone half my age.  Advancing scientific understanding isn't about ego; it's about pursuing what is true about the universe.

I also enjoyed new collaborations with a couple of engineers at Sheffield Hallam University.  Simon Choppin and John Kelley gave me new ways of looking at trajectory analysis when studying the flight of soccer balls.  I again benefited from engineering eyes looking at a problem I was used to seeing with a physicist's eyes.  And of course I continued working with my Japanese colleagues, Takeshi Asai and Sungchan Hong, at the University of Tsukuba.  We continued to combine my trajectory analysis and computational skills with their engineering and wind-tunnel skills to further what we know about soccer ball aerodynamics.  Working with engineers has helped my career more than I can describe here.

Equally important to me are my collaborations with Lynchburg College physics students.  Chad Hobson has made significant contributions to my soccer aerodynamics and Tour de France research.  Chad and I presented some of our work at ISEA 2016 in Delft, the Netherlands.  I am always looking for good physics students to research with me.  If you are a prospective student looking to contribute to sports physics, come to Lynchburg College and work with me!

There are many things I will miss about living in Sheffield.  I'll miss not having a car and using public transportation to get everywhere.  I'll miss my gym at Ponds Forge, which I hit six days in a row before we left Sheffield.  My family will miss the cute neighborhood we lived in where every kind of shop one could want was in short walking distance.  We'll all miss Endcliffe Park and the walking trails, playground, and ducks there.  I'll miss the chance to walk across the street to the Lescar for a pint.  I'll miss living in a place where guns aren't allowed -- for sure.  And of course I'll miss the Peak District, which is one of my favorite places on Earth.  We made one last visit to the Peak District the day before we left England and had to stop at the Fox House, one of our favorite Peak District pubs.

Before touching down in the US, we stopped for a few days in Iceland.  We stayed in Keflavík, which is a lovely little town on the water in the southwestern part of the country.  Visiting the Blue Lagoon was a must, and we thoroughly enjoyed ourselves there.  I had never been to a geothermal spa before and that one will be tough to beat!  The day after we were at the Blue Lagoon, we rented a car and explored the southwestern part of Iceland.  It was like driving on the set of a science fiction movie.  That is one interesting country to look at!  We stopped first at Gullfoss, a truly beautiful waterfall (click on the image for a larger view).

I took that photo on Wednesday, 27 July 2016.  Was that just two days ago?!?  Our second stop was to see Strokkur.  I shot a movie of the geyser doing a double belch (as I called it!).

Our third and final stop was Þingvellir, a meeting place for the North American and Eurasian tectonic plates.  Two plates are separating, but I thought I would help (click on the image for a larger view).

My arms might need to be a little longer!  We certainly enjoyed ourselves in Iceland and we want to go back so that we can explore some more.  But when?

As I wrote to start this post, my sabbatical journal writing ends now with the end of my sabbatical.  I can't emphasize strongly enough how important it is to interact with people from different countries, cultures, and backgrounds.  My wonderful wife introduced me to that concept on a trip to Japan we took in the summer of 2001.  She has been helping me appreciate that concept ever since.  And she makes all of our travel seem effortless and smooth.  I'll be back at work in my Lynchburg College office on Monday, 1 August 2016.  Waiting for me is research work from Sheffield and a pile of work related to the upcoming fall semester.  But I've got another year of wonderful memories dancing around in my head!

Greipel gets us under 1%!

André Greipel took the last stage of this year's Tour de France.  His time and a comparison with our prediction are given below.

• Stage 21:  2h 43' 08" (actual), 2h 41' 38" (prediction), 01' 30" fast (-0.92% error)

We'll definitely take that error to finish off this year's race!  Greipel's average speed is given below.

• Stage 21:  11.54 m/s (41.56 kph or 25.82 mph)

The big prize, of course, goes to Chris Froome who makes it three out of four.  Froome is now in the upper echelon of Tour de France cyclists.  I was wrong to pick against the defending champion!  Froome's average speed is given below.

• Chris Froome:  11.00 m/s (39.60 kph or 24.61 mph)

Not bad for 3528.5 km (2192.5 mi)!  Congratulations to Froome and all the cyclists for a great Tour de France.  I wish I could have seen more of the race, but my family will soon be moving across the pond.  And we've got packing to do!

Izagirre gets penultimate stage!

Jon Izagirre of Spain won this year's final mountain stage.  Spain can celebrate its first Tour de France stage win this year!  Izagirre's winning time and a comparison with our prediction is given below.

• Stage 20:  4h 06' 45" (actual), 4h 01' 44" (prediction), 05' 01" fast (-2.03% error)

I'll definitely take a 2% error on today's stage!  Izagirre's average speed is below.

• Stage 20:  9.895 m/s (35.62 kph or 22.14 mph)

Chris Froome will win this year's Tour de France tomorrow in Paris.  He has just over a four-minute lead on second place.  Our prediction for the lovely ride into the French capital is given below.

• Stage 21:  2h 41' 38" (prediction)

I hope it doesn't rain like it did last year!

Bardet makes France proud!

Romain Bardet gave France its first stage win of this year's Tour de France.  Below is Bardet's time and a comparison with our prediction.

• Stage 19:  4h 14' 08" (actual), 4h 04' 57" (prediction), 09' 11" fast (-3.61% error)

I'll take that error on such an arduous mountain stage.  Bardet's average speed is given below.

• Stage 19:  9.575 m/s (34.47 kph or 21.42 mph)

Froome still has the yellow jersey, and he widened his lead over second place.  Nairo Quintana could only cut ten seconds off of Froome's lead over him.  Tomorrow is the last shot climbers will have to take down Froome, but his lead looks mighty impressive for the final mountain stage.  A category-2 climb, two category-1 climbs, and an HC climb will have cyclists excited about the big downhill finish.  Our prediction is given below.

• Stage 20:  4h 01' 44" (prediction)

Will Froome hold the yellow jersey?  Hard to imagine losing it the way he's cycled this year.

Has Froome locked it up?!?

Chris Froome showed why he's a multiple Tour de France champion today.  He dominated the mountain time trial and makes me wonder if the Tour de France is over.  His winning time and a comparison with our prediction appear below.

• Stage 18:  30' 43" (actual), 29' 27" (prediction), 01' 16" fast (-4.12% error)

I was hoping the winner would come in under half an hour, but Froome was impressive nonetheless.  His average speed is below.

• Stage 18:  9.224 m/s (33.21 kph or 20.63 mph)

Froome won the first mountain stage and he dominated the mountain time trial.  I picked Nairo Quintana in my TOUR magazine interview.  Froome has a 04' 37" on Qunitana, and a nearly four-minute lead on second place.  There are two more mountain stages to go.  Time is running out!  Our prediction for Stage 19 is below.

• Stage 19:  4h 04' 57" (prediction)

Besides an HC-climb in the middle, a category-1 climb finishes the stage.  Another uphill finish!

Zakarin dominates the Alps!

Russian Ilnur Zakarin won today's arduous mountain stage with a time nearly a minute faster than anyone else.  This is Zakarin's first Tour de France stage win.  Below is Zakarin's winning time and a comparison with our prediction.

• Stage 17:  4h 36' 33" (actual), 5h 00' 10" (prediction), 23' 37" slow (8.54% error)

What's funny for me watching a stage is that I don't root for our prediction unless at the end I think we are really close.  I wanted to see the elite tackle today's mountains and come in under five hours.  And did they ever!  Check out Zakarin's average speed below.

• Stage 17:  11.12 m/s (40.03 kph or 24.87 mph)

That speed is 2 kph faster than what race organisers had as their upper limit on the time schedule.  Incredible to average 40 kph today!  We aren't happy to be more than 8% off today, but we'll have plenty to study when the race is over.  Several determined cyclists clearly outputted more power today than we had in our model.  We'll have a clearer picture of elite cyclist power output after this Tour de France is over.

Tomorrow's Stage 18 is a 17-km (11-mi) mountain individual time trial.  Cyclists will be back in France for the uphill time trial.  They'll get a chance to sprint on the downhill finish, though.  Our prediction is given below.

• Stage 18:  29' 27" (prediction)

I definitely want to see cyclists coming in under half an hour tomorrow.

Stage 17 Prediction

I'm busily getting items packed for our big move across the pond next week.  It hit me this afternoon that I'd not put our Stage 17 prediction online.  Well here it is:

• Stage 17:  5h 00' 10" (prediction)

Cyclists will compete in the Swiss Alps tomorrow.  A great category-1 climb to the 1527-m (5010-ft) peak at Col de la Forclaz will tire cyclists.  But they'll have to rejuvenate on the descent because the HC-climb to Finhaut-Emosson at elevation 1960 m (6430 ft) will challenge even the most elite cyclist.

Sagan gets 3rd stage win!

Peter Sagan has really discarded the bridesmaid label in this year's Tour de France!  I can recall so many stages in past years when he just missed out on winning a stage.  Below is Sagan's winning time and a comparison with our prediction.

• Stage 16:  4h 26' 02" (actual), 4h 46' 38" (prediction), 20' 36" slow (7.74% error)

We're not happy with that error!  I don't see any indication of tailwinds or anything similar that would make cycling fast today.  As I wondered at the end of yesterday's post, sprinters must have been going all out today.  Check out Sagan's average speed below.

• Stage 16:  13.09 m/s (47.14 kph or 29.29 mph)

That is incredibly fast, especially for a 209-km (130-mi) long stage.  Even race organisers didn't think the average speed would be above 44 kph.  To match Sagan's time (and the time of several other cyclists), our model cyclist would have needed nearly 21% more power output.  We've done really well on a few stages this year, and we've had weather and teams' strategies thwart us on a couple of other stages.  But we will have to take a closer look at today's stage.  Tour de France cyclists certainly impress us!

Tomorrow is the second and final rest day.  Cyclists will hang out in Berne, Switzerland.  Chris Froome still dons the yellow jersey.  This year's race will surely be decided in the Alps.  Get some rest tomorrow, cyclists.  You're going to need it!

Enjoyed a great time in Delft!

I'll be using this space as a sabbatical journal for another fortnight or so.  Nothing comes to a close faster than a fruitful, yearlong sabbatical in England!  But I've made the most of my time here, professionally and personally.  I've written a good bit about various trips my family has taken, but I've not written as much about my research.  There is a good reason for that.  I was waiting to publish and present significant pieces of research.  More research is set to be published, but I'll describe below some of the work that's kept me busy this past year.  My time in the Netherlands last week will be the perfect vehicle for that description.

I attended the 11th Conference of the International Sports Engineering Association in Delft (click here for the conference webpage).  I had never been to the Netherlands before.  It was fantastic!  I am both thoroughly impressed and incredibly jealous of the biking culture there.  Wide bike lanes sit adjacent to car lanes.  It was so easy getting around.  The neighbourhood where I live in Virginia doesn't even have sidewalks.  And biking is done at nontrivial risk because of speeding cars, a small fraction of which have drivers quite hostile to cyclists.  If my hometown had a biking setup like what I saw in Delft, I could easily see myself biking to work on a regular basis.  But riding on a 45-mph (72-kph) road, with some cars going well in excess of that speed limit, and no cycling lane make such an effort very unappealing.  Hopping back in my car when I return isn't exactly something I'm looking forward to.  But cycling in beautiful Delft was a lot of fun.  The photo below shows me on my rented bike in front of the conference centre (click on the image for a larger view).

I relish going to a research conference.  Meeting up with colleagues I've not seen in a year or more is just as great as meeting a slew of new people.  Besides four great keynote addresses, I attended 37 talks and gave two talks.  I couldn't see any more than that!  There were three parallel sessions, meaning lots of talks that interested me had to be missed.  As great as the talks were, the hallway discussions were even better.  Enthusiasm was contagious and it was easy getting excited about the smallest detail in another's work.  The organisers at Delft did a terrific job.  We enjoyed great food for lunches and snacks, and the final conference dinner was a blast.  I also loved getting to know people over beer and Dutch food in one of couple of lovely squares in town.  All of us had the common feeling of love for our work and passion to learn more.  I definitely left the conference with new ideas and novel ways to think about current research problems in my head.

My research efforts contributed three papers to the conference.  I like that conference papers weren't simply dumped without review into a "conference proceedings" book.  Papers for the Delft conference, like many other serious research conferences, were peer reviewed and allowed revision.  One of my papers benefited from a reviewer's insight.  Another reviewer gave good advice for the oral presentation I gave.  Peer review is an indispensable step in the advancement of good science.

Chad Hobson, my talented undergraduate physics student from Lynchburg College, joined me in Delft for the conference.  It is important to me that my research students publish and present their work.  Not all my students are able to achieve a publication, but that's a goal I've had since I began at Lynchburg College in 2002.  Chad presented our latest Tour de France work.  He is lead author on our paper (click here for that paper) and deservedly so.  His contributions to the work have advanced our Tour de France modelling in significant and critical ways.  Chad is in the middle of his talk in the photo below (click on the image for a larger view).

I've collaborated with colleagues at the University of Tsukuba on studies involving the aerodynamics of non-spinning soccer balls.  Previous work we published together showed why Brazuca was a better World Cup soccer ball than Jabulani.  I presented our current work that combined wind-tunnel experiments with trajectory analysis.  The latter approach is my speciality.  The photo below shows me in the midst of my soccer talk (click on the image for a larger view).

And, no, I'm not doing a Jedi mind trick!  The slide shows wind-tunnel force measurements, plotted in such a way as to illustrate stability, or lack thereof, in the five balls tested.  Click here for our paper.  We are getting a better understanding of knuckling effects.

My second presentation concerned part of the research I've done with my University of Sheffield colleagues.  We have investigated friction between various types of tennis shoe tread and a hard-court playing surface.  Sliding on hard courts isn't as prevalent as it is on clay courts, but it's becoming more popular.  I showed some of our treads in the slide below (click on the image for a larger view).

There are so many options for studying tread shapes and courts interacting with each other.  This research can certainly go on for years!  Our first paper on this topic is here.  We hope to have another one out soon.

Conference revelry was damped by the late-night news on Bastille Day that scores of people were killed in Nice.  And that news is on top of the seemingly continuous streams of bad news from my home country.  As I talked to people in Delft last week, I got such a strong sense of their hope and anticipation for future work.  I'm sure I exuded those desires as well.  Now think of all those killed in Nice and elsewhere.  Innocent people with hope and anticipation for their futures.  Gone.  Families ruined forever.  And for what purpose?  Making sense of the senseless is nearly impossible.  Maybe there will come a day when humans stop killing each other, but that day is a long, long way off.

Pantano gets 1st Tour de France stage win!

Columbia's Jarlinson Pantano won today's stage, his first Tour de France stage win.  Below is Pantano's time and a comparison with our prediction.

• Stage 15:  4h 24' 49" (actual), 4h 22' 06" (prediction), 02' 43" fast (-1.03% error)

Wind was not the factor today that it was yesterday, and our model got us near 1%.   We'll take it!  Below is Pantano's average speed.

• Stage 15:   10.07 m/s (36.25 kph or 22.53 mph)

Tomorrow's stage finishes in Switzerland.  Our prediction is given below.

• Stage 16:  4h 46' 38" (prediction)

The day after tomorrow's stage is a rest day.  Will cyclists increase their rest by holding back tomorrow in preparation for the Alps?  Or will they go for it, thinking the rest day will be all that's required before the big mountain stages?  We shall see!

Cavendish gets 4th stage win!

Mark Cavendish won his fourth stage of this year's Tour de France.  He won a stage in which riders fought massive headwinds all day.  One report I saw had the head wind nearing 40 kph (25 mph).  The wind killed our prediction, as seen below.

•  Stage 14:  5h 43' 49" (actual), 4h 53' 25" (prediction), 50' 24" fast (-14.66% error)

I know why we were so off, but I still hate to see so large an error.  We had that same error on Stage 3.  That stage reinforced the idea that we can be off if team strategies' are such as to hold cyclists back.  Today's stage is a reminder that not knowing the weather can lead to a bad prediction.  Check out Cavendish's average speed below.

• Stage 14:  10.11 m/s (36.39 kph or 22.61 mph)

That is incredibly slow for a flat stage, even a long one.  The slowest average speed the Tour de France time schedule makers considered was 40 kph (25 mph).  To match the time for today's stage, we would have needed to include a 10.7 kph (6.67 mph) headwind on our model cyclist -- for the entire 208.5 km (129.6 mi).  We didn't miss today's stage because of poorly implemented physics.  We missed it because we had no idea ahead of time that riders would face headwinds.  But that's part of the unknown associated with the modelling the Tour de France.

Tomorrow's Stage 15 contains two category-1 climbs and a big HC climb.  The stage features a fast descent to the finish.  Below is our prediction.

• Stage 15:  4h 22' 06" (prediction)

I like our prediction -- as long as Mother Nature doesn't get in the way!

Dumoulin Takes the Time Trial!

Tom Dumoulin of the Netherlands easily won today's individual time trial.  How appropriate that the same cyclist who won the stage when I arrived in the Netherlands last Sunday wins the stage on the day I left the Netherlands.  A great bookend for a wonderful time spent in Delft.  I'll write more about the conference in a few days, but for now, check out Dumoulin's winning time.

• Stage 13:  50' 15" (actual), 51' 42" (prediction), 01' 27" slow (2.89% error)

We did better modelling the third-place time than the first-place time, but we'll take getting a time trial to better than 3%.  Dumoulin's average speed is given below.

• Stage 13:  12.44 m/s (44.78 kph or 27.82 mph)

Now that's fast!  I can't even fathom going nearly 45 kph on a bicycle for more than a few seconds, and that's just Dumoulin's average speed.  Well done!

Chris Froome came in second today and extended his overall lead.  Below is our prediction for tomorrow's 208.5-km (129.6-mi) flat stage.

• Stage 14:  4h 53' 25" (prediction)

Enjoy the stage, sprinters, because more mountains are on the way!

Crazy Stage 12!

Stage 12 was cut short by 6.5 km because of incredibly fast winds at the summit of Mont Ventoux.  Thomas De Gent of Belgium won today's truncated stage.  His winning time and a comparison with our pediction are given below.

• Stage 12:   4h 31' 51" (actual), 4h 37' 31" (prediction), 05' 40" slow (2.08% error)

We'll definitely take that error on a botched final climb with crazy weather!  De Gent's average speed is given below.

• Stage 12:   10.88 m/s (39.19 kph or 24.34 mph)

Below is our prediction for tomorrow's individual time trial.

• Stage 13:   51' 42" (prediction)

I wish I could comment more on today's stage but I was tied up with the last day of a great conference in the Netherlands.

Sagan gets #2!

Peter Sagan won a very fast Stage 11 today.  Below is Sagan's winning time and a comparison with our prediciton.

• Stage 11:  3h 26' 23" (actual), 3h 45' 22" (prediction), 18' 59" slow (9.20% error)

Sagan's average speed is given below.

• Stage 11:  13.12 m/s (47.24 kph or 29.35 mph)

I confess that I am stunned by that average speed.  Cyclists were fast today!  I can't imagine that average speed for myself.  Tour de France cyclists are the best of the best for sure.  Did they know ahead of time that tomorrow's massive climb to Mount Ventoux was going to be cut short because of massive winds at the summit?  They had to know they'd not need to save as much energy for tomorrow.

We learned that the final 6.5 km of tomorrow's last climb will be cut from the stage.  Below is our original prediction, our original prediction for the final 22 km, and our prediction based on removing the final 6.5 km.

• Stage 12:  4h 55' 23" (prediction)
• Stage 12:  58' 54" (prediction for final 22 km)
• Stage 12:  4h 37' 31" (prediction with final 6.5 km missing)

If the race committee does exclude the final 6.5 km, we'll go with the last time on the above list as our prediction.  It's too bad the final climb has to be cut short.  We've been waiting on that climb since it was released.

Matthews grabs Stage 10!

I enjoyed a great first day of research talks here in Delft, the Netherlands.  The conference is off to a good start!  But being tied up all day in a conference means I couldn't see any of the Tour de France.  I'm back in my hotel room for a few minutes before heading out to dinner.  Below is Michael Matthews' winning time and a comparison with our prediction.

• Stage 10:   4h 22' 38" (actual), 4h 32' 45" (prediction), 10' 07" slow (3.85% error)

I wish I could comment more on the stage, but I'll take being under 4% today.  Matthews' average speed is given below.

• Stage  10:  12.50 m/s (45.01 kph or 27.97 mph)

Not bad, considering that first big climb.  Our prediction for tomorrow's flat stage is given below.

• Stage 11:  3h 45' 22" (prediction)

We could be a bit slow tomorrow if the sprinters go crazy.  But they better not get too tired.  What awaits them on Stage 12 will make them pay for going all out tomorrow!

Stage 10 Prediction

My student, Chad Hobson, and I are having a great time in Delft, the Netherlands.  I saw old friends today that I'd not seen in several years.  We also met several new people and toured the labs at Delft.  Nothing like being around people excited about research!

Below is our Stage 10 prediction.

• Stage 10:   4h 32' 45" (prediction)

Read about tomorrow's medium mountain stage online.  I'm having too much fun in Delft and need to get back on my bicycle and explore the city!

Dumoulin takes Stage 9!

I've been travelling all day and I missed yet another Tour de France stage.  Nothing like being in Europe and not watching the best bike race on the planet!  Below is Tom Dumoulin's winning time and a comparison with our prediction.

•  Stage 9:  5h 16' 24" (actual), 5h 02' 33" (prediction), 13' 51" fast (-4.38% error)

From what I read, there were thunderstorms at the finish.  Did that slow riders down and lead to the above discrepancy?  Please e-mail me and let me know!  I love it that Dumoulin is from the Netherlands, and I'm in the Netherlands right now!  I'm here for an international research conference.  My student, Chad Hobson, is here, too.  We are checking out the Euro 2016 final while I'm writing this blog post.  Portugal just won it!

Below is Dumoulin's average speed.

• Stage 9:  9.719 m/s (34.99 kph or 21.74 mph)

Tomorrow is the Tour de France's first rest day.  I'll get our Stage 10 prediction up before tomorrow comes to a close here in the Netherlands.  Until then, we'll be happy with our prediction today.

Froome grabs the yellow jersey!

Oh how I wish I could have seen today's stage!  We have friends visiting from the US and we showed them Sheffield for the entire day, from a traditional tea to a pub visit to time in the park.  But I missed Stage 8 as Chris Froome dominated the competition to take the yellow jersey.  Below is Froome's wining time compared to our prediction.

• Stage 8:  4h 57' 33" (actual), 4h 50' 14" (prediction), 07' 19" fast (-2.46% error)

Now that's an error we can tolerate!  We are back under 2.5%, which is great.  Froome's average speed is given below.

• Stage 8:  10.31 m/s (37.10 kph or 23.05 mph)

That's impressive!  Even though we predicted a slightly better time, Froome still completed the stage in a time that amazes me.  Well done!

From Spain to Andorra, tomorrow's Stage 9 is a 184.5-km (114.6-mi) mountain stage that will have riders battling in the Pyrenees.   Three category-1 climbs, including at the start, will have riders tired by the time they get to the HC climb to finish the stage at the ski resort of Andorre Arcalis where the elevation is 2240 m (7349 ft).  Our prediction is given below.

• Stage 9:   5h 02' 33" (prediction)

I fully admit that we are predicting a fast time.  Come on, climbers, challenge Froome tomorrow!

Steve Cummings wins a FAST stage!

Tour de France cyclists never cease to amaze me.  They set a torrid pace today.  Below is the winning time for Steve Cummings and a comparison with our prediction.

• Stage 7:  3h 51' 58" (actual), 4h 11' 35" (prediction), 19' 37" slow (8.46% error)

We're not happy with that error!  Check out Cummings' average speed below.

• Stage 7:  11.68 m/s (42.03 kph or 26.12 mph)

 That's at the top of the time schedule range; our prediction was closer to the bottom of that range.  Cyclists enjoyed a bit of a tailwind, but temperatures were comparable to yesterday's stage.  The competition to reach the summit of Col d' Aspin was fierce and the downhill sprint that followed the climb was incredibly fast.  Kudos to the cyclists for dazzling us once again!

Tomorrow's 184-km (114-mi) Stage 8 is this year's first mountain stage.  Beginning in Pau, cyclists will head southeast through the Pyrenees to Bagnères-de-Luchon.  A massive HC-climb to the 2115-m (6939-ft) summit of Col du Tourmalet highlights the beginning of the stage.  As if that weren't enough, cyclists will tackle a category-2 climb and two category-1 climbs before a fast downhill sprint to the finish.  Below is our prediction.

• Stage 8:  4h 50' 14" (prediction)

That prediction amounts to a fast day of racing.  We want to see racing tomorrow like we saw today!

Cavendish gets #3 this year!

Mark Cavendish picked up his third stage win in this year's Tour de France.  Cycling was a bit slow today.  The peloton took it easy at times and cyclists seemed to be affected by the heat.  Temperatures got to about 30 C (86 F), which is hot enough to be bothered when one's cycling competitively for nearly five hours.  Below is Cavendish's winning time and a comparison with our prediction.

• Stage 6:  4h 43' 48" (actual), 4h 21' 26", 22' 22" fast (-7.88% error)

We were a bit fast today, though I think the heat played a role in slowing cyclists down a little.  Below is Cavendish's average speed.

• Stage 6:   11.19 m/s (40.27 kph or 25.03 mph)

Had we know about the heat, we might have pulled the power down a little.  But our model has done really well on four of the six stages so far, although we messed up one of those four when we cut the power too much.  We were under 8% today, which was something we thought of as good a decade ago.  Now we want to do better!

Stage 7 is 162.5-km (101.0-mi) long medium-mountain stage that begins in the commune of L'Isle-Jourdain.  A category-1 climb to the 1490-m (4888-ft) summit of Col d'Aspin near the end of the stage will introduce the riders to the French Pyrenees.  I can't wait to see that climb!  After the summit will be a downhill sprint to Lac de Payolle.  Our prediction is below.

• Stage 7:   4h 11' 35" (prediction)

Did cyclists save some energy today for tomorrow's big climb?  If so, we could be a little slow.  But we'll see how the model performs tomorrow.

Our model does the job today!

After yesterday's disastrous decision to drop cyclist power output by 20%, and thus missing the chance to have publicly predicted Stage 4 to 0.24%, we put our trust in our model for today's Stage 5.  It sure paid off!  Belgium's Greg Van Avermaet got his second career individual stage win in the Tour de France, and he wrested the yellow jersey from Peter Sagan.  Below is Avi's winning time and a comparison with our prediction.

• Stage 5:  5h 31' 36" (actual), 5h 29' 33" (prediction), 02' 03" fast (-0.62% error) 

It's great being back under 1%!  Below is Avi's average speed.

• Stage 5:  10.86 m/s (39.08 kph or 24.29 mph)

Given the climbs in today's stage, that's an impressive average speed.

Tomorrow's Stage 6 is a 190.5-km (118.4-mi) flat stage with an impressive downhill just 23.5 km (14.6 mi) into the stage.  Beginning in the commune of Arpajon-sur-Cère, cyclists will head southwest to Montauban.  The Pyrenees are getting closer!  Below is our prediction.

• Stage 6:  4h 21' 26" (prediction)

We're sticking with our model -- no power tweaking.  I'll be anxious to see if we've figured out Stage 6.

Kittel sprints to victory!

Yesterday's stage and today's stage provided us with a real learning experience, and a humbling one at that.  Last year was the first time we made adjustments to our model while the Tour de France was taking place.  We tried to make tweaks based on strategies we thought were in play.  For the most part, our adjustments worked extremely well.

Now to today's learning experience.  Marcel Kittel won today's stage 4 with the time given below.

• Stage 4:   5h 28' 30" (actual), 5h 56' 59" (prediction), 28' 29" slow (8.67% error)

After yesterday's enigmatic slow stage, we thought cyclists were holding back, saving energy for later stages.  Given that today's stage was longer than yesterday's stage, we thought power outputs would be reduced again.  As I noted yesterday, we would have needed to cut power by a third to hit yesterday's time.  We decided to cut power by 20% today, thinking we'd see another slow stage.  We should not have done that!  I cringed when I saw that had we not altered our model by reducing the power, we would have missed today's stage by just 47".  Getting spooked by yesterday's stage caused us to think that teams' strategies were such that we had too much power for the long, flat stages.  We should have seen yesterday as an anomaly and trusted our model for today's stage.  But we can't go back in time and claim a great prediction today.  Our model performed great; we misread the cyclists' strategies.  Part of good science is being as honest as possible.

Below is Kittel's average speed.

• Stage 4:  12.05 m/s (43.38 kph or 26.95 mph)

We are going to trust our model for tomorrow's Stage 5, which is a 216-km (134-mi) medium-mountain stage that starts in Limoges, where Stage 4 ended.  Cyclists will head southeast to the mountain resort of Le Lioran.  Two category-2 climbs near the end of the stage should make for great racing.  Our prediction is given below.

• Stage 5:   5h 29' 33" (prediction)

We'll stick with our original prediction and hope racing tomorrow is more like today than yesterday.

Cavendish makes it two out of three!

Today's Stage 3 was as bizarre a Tour de France stage as I've ever seen.  It was SO SLOW!  The peloton looked like molasses moving down the road.  After nearly six hours, Mark Cavendish crossed the finish line.  Below is his winning time and a comparison with our prediction.

• Stage 3:  5h 59' 54" (actual), 5h 07' 03" (prediction), 52' 51" fast (-14.68% error)

 I need to check my archives, but that might be the worst prediction we've ever made!  Check out Cavendish's average speed below.

• Stage 3:  10.35 m/s (37.26 kph or 23.15 mph)

Keep in mind that today's stage was a flat stage.  The above average speed is comparable to what we've seen on a few mountain stages.  It's also nearly 2 kph less than the slowest time schedule average speed given by Tour de France organisers.  No wonder race commentators were using phrases like "slow motion" and "snail's pace"!

As happy as we were to be under 1% yesterday, we're just as mystified to be nearly 15% off today.  I tell audiences during my Tour de France talks that there are many things we cannot know about the race, and teams' strategies are right at the top of the list.  The same model that nailed yesterday's stage needed its cyclist power output cut by nearly a third today.  Riders were clearly holding back, and I don't claim that because we had such a bad prediction.  Learning as the race unfolds is a lot of fun, and we certainly learned something today.

Tomorrow's Stage 4 is a 237.5-km (147.6-mi) flat stage, which is this year's longest stage.  Were cyclists saving energy today for tomorrow's long ride?  That could very well have been the teams' strategies.  Beginning in the commune of Saumur, the stage takes riders southeast to Limoges.  Below is our prediction.

• Stage 4:  5h 56' 59" (prediction)

The above would have been a great pick for today!  Tomorrow's stage is 14 km (8.7 mi) longer than today's stage.  I hope the peloton moves a little faster tomorrow.

Sagan gets us under 1%!

I always think of Peter Sagan as coming in second.  There are so many stages of the Tour de France that I remember Sagan just coming up short.  That wasn't the case today as The Terminator took Stage 2.  Below is Sagan's winning time and a comparison with our prediction.

• Stage 2:  4h 20' 51" (actual), 4h 22' 59" (prediction), 02' 08" slow (0.82% error)

We're always excited to be under 1%!  Sagan's average speed is given below.

• Stage 2:  11.69 m/s (42.09 kph or 26.16 mph)

 Sagan now has the yellow and green jerseys.  Mark Cavendish sits in 75th place out of 198 riders.

Tomorrow's Stage 3 is 223.5 km (138.9 mi) long and classified as flat.  Beginning on the coast at Granville, the stage takes riders south to the city of Angers.  Our prediction is given below.

• Stage 3:  5h 07' 03" (prediction)

Our prediction is a bit of a challenge to the cyclists.  We want to see a rider finish the stage close to five hours.  That's a long time in the saddle!

Manx Missile Gets #27!

Mark Cavendish took the first stage of this year's Tour de France, earning his 27th Tour de France stage win.  Amazing!  Below is Cavendish's winning time and a comparison with our prediction.

• Stage 1:   4h 14' 05" (actual), 4h 20' 25" (prediction), 06' 20" slow (2.49% error)

We'll definitely take that error on the first stage!  Here is Cavendish's average speed:

• Stage 1:  12.33 m/s (44.39 kph or 27.59 mph)

Cavendish will don the yellow jersey for tomorrow's 183-km (114-mi) Stage 2.   The hilly stage begins in the commune of Saint-Lô, moves south, then southwest, before turning north along the coast toward the commune of Cherbourg-en-Cotentin.  Our prediction is given below.

• Stage 2:  4h 22' 59" (prediction)

There are three category 4 climbs early on and a category 3 climb to finish the stage.  Will Cavendish be able to enjoy his first yellow jersey for more than a day?

Time to Get Rolling -- Stage 1 Prediction

The 103rd Tour de France commences tomorrow.  For those of us that follow the yearly race, a day like today makes us say, "Finally!"  I thoroughly enjoyed giving my talk this afternoon on my Tour de France and World Cup football research work.  I tried to whet the appetite of those in the audience anticipating the start of tomorrow's first stage.  My colleague, Zing, snapped the photo below just before my talk got underway (click on the image for a larger view).

I unveiled our Stage 1 prediction during the talk, but before I do that in this space, a few more words.  In past years, I've watched the Tour de France in my Lynchburg College office via an internet feed.  I could snag a few images of each stage by simply printing my computer screen to a file.  Stages would usually end around noon, meaning I could watch in the morning and still work a mostly full day afterwards.  Now that I'm in England, stages will be run during afternoons, finishing in early evenings.  That makes it much harder for me to follow the race and still get lots of work done.  So despite being much closer to the action this year, my blog posts will be less detailed and contain fewer images.  I'll still post a prediction before each stage is run, though.

Tomorrow's Stage 1 begins in the French commune of Mont Saint-Michael.  Cyclists will head mostly north along the coast for the 188-km (117-mi) flat stage, which ends on Utah Beach in Sainte-Marie-du-Mont.  Below is our prediction.

• Stage 1:  4h 20' 25" (prediction)

Will we be fast?  Slow?  Nail it?  Who knows?  But it'll be fun seeing how close we come!

Who will win this year's Tour de France?

I don't know!  That response happens to be one of the best responses a scientist, or anyone for that matter, can give to a question.  No reason to assert a claim without data and evidence to support the claim.  As a scientist, I'm trained to make conclusions based on data and evidence.  But I've had a lot of fun in recent years publishing Tour de France stage-winning-time predictions on this blog.  My research students and I have honed a physical model for a dozen years now.  The recipe is fairly simple.  We take stage profile data, add some cyclist power output, toss in some air resistance and road friction, and then mix the ingredients up with the laws of physics.  A tasty summer treat indeed!

But the question that serves as this post's title is one I'm asked by media every year.  It's a fun question because I can't possibly know what will happen over the course of a gruelling three-week-long race.  Will there be big crashes?  Injuries?  Which stages will be hit with bad weather?  Cycling teams certainly aren't sharing their strategies with me.  I do freely admit, though, that publishing our winning stage-time predictions prior to each stage being run has made the science much more exciting -- and the science was already exciting!

For the first time, I made a prediction for the overall winner.  I did so with all the caveats mentioned in the previous paragraph.  Will I feel bad if my pick doesn't win?  As long as he competes well and doesn't get injured, no, I won't feel bad.  There are a handful of elite riders with strong teams who have legitimate shots at winning cycling's most famous race.  I picked one of them -- but I'm not revealing the name in this space.  At least not yet.  I was recently interviewed by TOUR Magazine, which is based in Germany.  My prediction for the overall winner sits on page 36 of the current issue (July 2016).  Because the magazine was gracious enough to chat with me about my Tour de France research work, I'll throw the magazine a little love and ask that if you're really interested in my pick, you'll go there.

The 103rd Tour de France begins day after tomorrow (Saturday, 2 July).  I've been invited by the Department of Mechanical Engineering here at the University of Sheffield to give a talk on my Tour de France and World Cup football research.  My talk will begin at 2 pm on Friday, 1 July and will be held in LT 15 in the Sir Frederick Mappin Building.  I plan to unveil our Stage 1 prediction during the talk.  I'll also post our prediction after the talk in this space.  If asked during Q&A, I may even offer my pick for this year's winner!

Writing a Good Journal Article

I gave an invited talk today at the University of Sheffield.  The topic is important to me, but the topic had never been the subject of one my talks before.  I was asked to talk about writing a good journal article.  Sure it's something I've learned to do over the years, and it's something I've counselled students on during my time at Lynchburg College.  I've written a couple dozen research articles in my life, including a long review article, and I've written a book for the general public.  But how to describe writing in a talk?  That was definitely out of my comfort zone!

Like any challenge I face, I embraced the task before me and thought about how I could describe good journal writing in a 50-minute talk.  Writing for me is so discombobulated at times.  I jump right in, write a few paragraphs in what will eventually be the middle of the paper, and then I do something else.  The main struggle in preparing today's talk was how to present something nonlinear in a linear way.  Whether I succeeded or not is up to the audience.

The audience, by the way, was great!  I got lots of though-provoking questions.  At least half the audience spoke English as a second language.  I admire those people because not only are they bilingual, something I wish I could join my wife in being, they are making wonderful strides to improve their English and publish the exciting research work they do.  It has to be daunting to express thoughts and ideas in ways one is not accustomed to doing.

My colleague, Zing, was gracious enough to snap a couple of photos of me while I was giving my talk.  The one below shows me just getting going (click on the image for a larger view).

I wish I had a better way to hold my reading glasses, but the top of my head is what works for me!  It was fun giving a talk on a new topic, one I'd not thought of as a talk topic before I was asked to make it a talk topic.

Rock Climbing in the Peak District

After getting turned around in the fog a couple of weeks ago, I made another attempt to see the beautiful sights atop the rocky promontories on Hathersage Moor.  My wife, younger daughter, and I experienced a lovely day in the Peak District this past Sunday.  No fog got in our way!

We began our hike southeast of where the A6187 meets up with the Burbage Brook.  Carl Wark was our first destination.  My younger daughter likes to describe herself as a mountain goat because of her skill navigating over and up rocks and boulders.  She's certainly our family's best climber!  I snapped a photo of the Hathersage Moor while on the way down from Carl Wark (click on the image for a larger view).

We then made our way to Higger Tor.  The photo below was taken from Higger Tor and shows Carl Wark to the left (click on the image for a larger view).

Is that a gorgeous view or what?!?  We had no climbing equipment, so we avoided the sheer rock faces and hike up the scattered boulders.  That might have been more fun than climbing with ropes.  We had to think about which path to take and where to step.  My daughter did a great job leading her proud dad up to the top.

Not content with two promontories, we left Higger Tor and hiked up to Stanage Edge.  The photo below shows millstones made from gritstone and some of the sheep we met on our hike (click on the image for a larger view).

We had a lot of fun walking through the tall bracken; some of it was as tall as my daughter.

The walk back gave us a couple of interesting moments.  I was leading my daughter as we neared the Burbage Brook when I stepped in a sink hole.  Before I knew it, I had mud a few inches above my boots.  I didn't panic and sink any more than that, and I was able to get myself out.  I'm glad my daughter wasn't leading; she would have sunk in to her knees at least.

We had to jump across the Burbage Brook.  I did fine, but my daughter slightly lost her nerve as she jumped from the bank.  I caught her, but her trailing boot landed in the water.  I pulled her out quickly.  She then sat on a boulder and took off her boot.  I couldn't help but laugh when she turned her boot over and a bunch of water spilled out.

After all that fun we had a great meal at the Fox House pub.  We've never had a bad meal there!

Brexit After All

The votes were tallied and nearly 52% of those votes supported the UK leaving the EU.  I knew the vote would be close -- all polling leading up to the vote suggested as much -- but I confess I'm surprised that "remain" didn't carry the day.  These are strange political times we live in.  Both left and right have serious divisions with them.  Here in England, I've heard isolationists on the right who fear the "other" side with some on the left who want to blow the establishment system up, thinking that starting over is the only way revolution will happen.  Strange bedfellows indeed.

While on a recumbent bike at the gym this morning, I watched on live television the British Prime Minister resign.  That David Cameron would leave isn't a shock, but it was something else watching it happen in real time.  He'll likely leave in October.  My family picked an interesting year to be in England!  We'll leave an England at the end of July that will be rather different from the one we'll visit if we are lucky enough to return in the future.

The Brexit vote reminds me of just how divided people are on certain ways of viewing the world, and how the groups rarely intermingle.  I admit that I wanted the UK to remain in the EU, and essentially everyone I know here feels the same way.  At least three times this morning I heard something like, "Everyone I know voted to remain.  How did we lose?"  While working at a university, I primarily interact with people in academia and professionals with "white collars."  I simply don't cross paths with the large number of people in Sheffield who work "blue collar" jobs in various industries.  I certainly don't view one group as being better than the other; my career choice has put me in proximity with one group.  I learned this morning that Sheffield voted to leave by a margin of 51% to 49%, meaning the people I associate with were part of the minority opinion.

I've heard much talk about there being "two Americas" in the US.  We will have a choice this November between two candidates who poll at #1 and #2 historically on how much they're despised.  And both have earned those rankings.  But people who support one candidate can hardly fathom the thinking going on inside the heads of those support the other candidate.  I can't help being like that myself.  It has always been a complete mystery to me why so many in my country support citizens owning semi-automatic (or fully automatic) weapons.  And that's just one example of many that make me feel like I'm part of one of the two Americas.

It will be interesting to see how everything unfolds as the UK moves forward.  We'll certainly be keeping up with UK politics after returning to the US.

Great Father's Day in Hathersage!

There was no way I could attempt to stay up all last night and watch the deciding game of the NBA Finals.  The game here began at 1 am today.  So I made sure to enjoy myself all of yesterday for Father's Day.  I've been called "son," "brother," "husband," and "uncle" in my family life, the latter of which has been particularly fun.  In my professional life, I've been called "doctor" and "professor," though I've never liked all those titles.  The one title I love above all others is "daddy," which has evolved to "dad" as my girls have gotten older.  Hearing "dad" always makes me happy and represents the best way a part of me can live on after I die.

My wife and daughters know how much I love the Peak District, so we all went to Hathersage for a little walking and a visit to a great country pub.  Because my older daughter has a broken left pinkie toe, we kept walking to a minimum.  Walking the countryside was still a lot of fun (click on the image for a larger view).

I never tire of the lush green grass on the English countryside.  We walked along River Derwent for awhile before crossing it to get to a pub (click on the image for a larger view).

After walking got our appetites ready for a pub visit, we nipped into The Plough Inn.  We had wonderful food there, including delicious desserts that should be reserved for special occasions only.  Give The Plough Inn a try if you're ever in Hathersage.

My wife and daughters gave me a great Father's Day yesterday, though every day feels like Father's Day when I'm fortunate enough to hear my daughters call me "dad."

From Joy to Sadness

I have so thoroughly enjoyed my time in Europe over the past year.  It is hard for me to believe that my family will be flying home in about six weeks.  I have also enjoyed using my blog for a sabbatical journal.  I've been able to record thoughts on holidays my family has taken, and I've noted times when I've interacted with media and given talks.  There has been some sports science writing, too, which is how this blog got started.  At the beginning of this week I put a few words in this space that pertained to the massacre in Orlando.  And now something else has happened to motivate me to write outside my comfort zone.

Just before 2 pm yesterday, my research colleague and I joined a couple of his colleagues and watched England's thrilling 2-1 win over Wales.  We all felt joy as England pulled out the win with an exciting goal late in the match.  But in the middle of the match, my colleague checked his phone and saw that an MP from West Yorkshire had been stabbed and shot.  That was big news, partly because gun crime is so rare here and partly because the last time an MP was murdered was in 1990.  My colleague said the name Jo Cox, and though I'm not sure, that may have been the first time I heard her name.  I've watched and read a lot of BBC while living here.  And I've followed the Brexit debates rather closely.  It is entirely possible I've heard the name Jo Cox before, but I don't remember.  It takes awhile for a visitor like me to learn all the names and places involved in important issues.

When I got home from work, my wife and I learned that Jo Cox had died from her wounds.  I spent a little time last night getting to know her from various websites.  She pursued ethical and humane solutions to the problems in Syria.  She saw it as a moral obligation to help migrants fleeing the strife in Middle East conflicts.  Her website highlights recent efforts to help people with cancer.  And some deranged individual takes her life because, from all reports I've read, he hated her position on the Brexit issue.  Wow.  A woman who has done more good for more people than her murderer could fathom is dead because of her political stances.

Hatred of the "other" is a powerful motivator for some people.  I've seen too much of it my country, and it's sad to see it here in England.  Less than a week ago, 49 people were slain because of hate, fear, and credulity.  And I may be guilty of possessing the brain state based on the fact that the more people killed in a given atrocity, the more abstract the event becomes for those not directly affected.  After all, it is much easier and less time consuming to read about one murdered MP than it is to read about 49 victims of a mass shooting.  It may not be fair, but that's the way it is.

There will always be certain stories that tug at our empathy.  I learned that Jo Cox is survived by a husband and two children, ages 3 and 5.  Seven years ago, my family was preparing to leave England.  I was nearing the end of my first sabbatical, also spent at the University of Sheffield.  My daughters at that time were ages 3 and 5.  I cannot even imagine leaving England then without their mother.  Putting aside what my own grief would have been like, I cannot even imagine what my girls' lives would have been like in the past seven years without their extraordinary mother.  It is empathy that plays a large role in the solidarity we humans have with each other.  And it is empathy that makes me feel sick to my stomach when I think about what happened yesterday.