Friday, March 16, 2018

Getting Rid Of Laptops In College Classes - A Good Idea!

Image may contain: one or more people
General Physics students, ca. 1970 at USF, taking notes in lecture hall.
No automatic alt text available.
Partial view of my class notes for Stellar Evolution course, Spring, 1971.

The front page WSJ piece, 'I'd Be An 'A' Student If I Could Just Read My Notes', (March 13),  garnered little sympathy from me, and I am sure the many professors who now have declared laptops off limits in class.  To those of us in an older generation, taking notes by hand in college - using cursive (e.g. actual handwriting) - ought to be no biggie. You just do it.

But according to the WSJ article, today's crop of college students feel handicapped without their laptops. According to one quoted in the piece: "I always had beautiful, color coded notes in high school"  but was shocked to learn many professors at Georgetown University "don't allow laptops in their lecture halls"

And who can blame them? The clacketty clacking of fingers plunking on a keyboard is definite distraction especially multiplied by dozens. Also, the sight (for a lecturing prof) of so many heads geared to the assorted laptop monitor screens.   As noted (ibid.):

"Professors are weary of looking out over a sea of laptops, with students' faces aglow from who knows what. Are they taking notes? Ordering sneakers on Amazon? Checking out memes?"

Indeed, or perhaps going to a porno site. Professors aren't sure and they'd rather have the devices out of the lecture room entirely. Besides, it's good for the students and hand notes enable better learning (see the SciAm link at the bottom).

According to one professor  (Carol Holstead) at the University of Kansas quoted in the article:

"I really get tired of seeing them out there on their laptops and doing something other than pay attention to me."

True to her take she banned all laptops three years ago and "now tells students when it is time to pick up their pens and take notes on a particular point."

Seriously? She is way too generous.  In my years at Loyola, - and later USF- whether the course was Theology, Ethics, Logic, Biblical Exegesis,  English literature, chemistry, physics, geodesy or celestial mechanics  - the onus was on the student to have the common sense (and intelligence) to know when to take notes and when not to. We had no Jesuit profs (or transplanted Yale profs at USF) giving us heads ups on what parts of lectures were note-worthy. Talk about coddling!  Don't believe me? Then take in this balderdash (ibid.):

"Students complain professors just don't understand how hard it is to write by hand."

Awww....give the little infants a sippy  cup. But a large part of the problem is that "a whole generation of students never learned to write in script and have entered college."

In 1964 at Loyola, this would have been cause to instantly pull an admission as unqualified because of basic incompetence.  I mean, writing in script - as for note taking in courses - was taken for granted as much as being able to use a slide rule in physics class, or using the Dewey decimal system in library research - say for a philosophy or English lit paper. In today's context it would be judged roughly the same as being able to use a smart phone.

So how  do today's little dweebs manage without laptops and someone telling them it's  note taking time? Evidently, there are loads of strategies including: "using abbreviations and getting  notes from  classmates with better penmanship". Also,  "recording lectures on cell phones.". . (Which, of course, means the notes must be transcribed later).

There are also ways to be granted an exception. For example, college faculties that disallow laptops will make exceptions for students with disabilities, and conditions such as dyslexia and dysgraphia (an inability to write properly). The problem with invoking these excuses is that faculty will be obliged (usually) to explain to other conforming students why there are 'x' exceptions. In that case, the students claiming the disability or condition are "outed".

This will lead students who might otherwise be tempted to get an excuse to think twice. Like a Univ. of Connecticut kid - Christopher Wojick - quoted in the article, e.g.

"The class was ridiculously hard to take notes in and I was thinking. ' I have a disability?"

He acknowledged being close to "making something up" then "thought the better of it."  So is now toughing it out with his note taking. Good idea, at least he proved he wasn't a total wimp. (See also the terrific book, A Nation Of Wimps -by Hara Estroff Marano. She documents how  the current generation of college students are hobbled in their skills, coping abilities, etc. with helicopter parents to boot.

What should a high school student do today to prepare for college note taking? Easy, take a penmanship course or learn it on your own! An hour or so practice a day, and by the time the fall semester begins you ought to be proficient in note taking.

See also:


When it comes to college students, the belief that more is better may underlie their widely-held view that laptops in the classroom enhance their academic performance.  Laptops do in fact allow students to do more, like engage in online activities and demonstrations, collaborate more easily on papers and projects, access information from the internet, and take more notes.  Indeed, because students can type significantly faster than they can write, those who use laptops in the classroom tend to take more notes than those who write out their notes by hand.  Moreover, when students take notes using laptops they tend to take notes verbatim, writing down every last word uttered by their professor.

Obviously it is advantageous to draft more complete notes that precisely capture the course content and allow for a verbatim review of the material at a later date.  Only it isn’t  New research by Pam Mueller and Daniel Oppenheimer demonstrates that students who write out their notes on paper actually learn more.

Thursday, March 15, 2018

Selected Questions -Answers From All Experts Astronomy Forum (Astronomical Coordinates)

Question: I am interested in how astronomical coordinates and angles are computed and the geometry involved. Also can you show an example of how one can calculate a star's declination, say, using known angles?


The sub-discipline to which you refer, computing astronomical coordinates, including in differing coordinate systems, is called "practical astronomy".  The term implies little or no theorization just straight out, bare knuckle observations and mathematical computations.  Practical astronomy entails learning about the mechanics of the sky: how to measure angles and reference coordinates, then how to use these to find astronomical objects in terms of their positions, including altitude for the observer, as well as azimuth.

But before one can do all those things, one has to become au fait with the basic sky coordinate systems and geometry, ultimately working in the basic relations for spherical trigonometry. This is merely an extension of plane trig, but to the sort of angles (many > 90 degrees) one finds in spherical or astronomical applications.

A simple illustration of a spherical geometry is shown in Fig. 1. In the diagram, the angle Θ denotes the longitude measured from some defined meridian on the sphere, while the angle φ denotes a zenith distance, or the measured angle from an object to the zenith.

Fig. 2 shows a spherical right triangle from which a host of different angle relationships can be obtained, which can then be used to find astronomical measurements, etc.

Fig.3 shows an actual example of a celestial sphere, such as used in many practical astronomy applications, and some of the key angles with reference to a particular object (star) referenced within a given coordinate system. In some applications, the coordinate system may not need to be changed, but in others it must - for example, when going from the coordinate system applied to sky objects (Right Ascension, Declination) to the observer's own coordinates (altitude, azimuth). In this way, coordinate transformations will also enter and we'll get to those in time.

For now, let's just consider a simply angle relation in Fig. 1, to find the altitude, a. Then if we have the basic geometrical relationship: a + φ = 90 degrees, clearly then a = (90 - φ ).

Let's now examine Fig. 2 and see what spherical trig relationships we can infer.

Two of the key ones embody the law of sines and law of cosines for spherical triangles, which are the analogs of the law of sines and cosines in plane trig.

We have for the law of sines:

Sin A/ sin a = sin B/ sin b = sin C/ sin c

where A, B, C denote ANGLES and a,b,c denote measured arcs. (Note: we could also have written these by flipping the numerators and denominators).

We have for the law of cosines:

cos a = cos b cos c + sin b sin c cos A

Where a, b, c have the same meanings, and of course, we could write the same relationship out for any included angle.

Now, we use Fig. 3, for a celestial sphere application, in which we use the spherical trig relations to obtain an astronomical measurement.

Using the angles shown in Fig. 3 each of the angles for the law of cosines (given above) can be found. They are as follows:

cos a = cos (90 deg - decl.)

where decl. = declination

cos b = cos (90 deg - Lat)

where 'Lat' denotes the latitude. (Recall from Fig. 1 if φ is polar distance (which can also be zenith distance) then φ = (90 - Lat))

cos c = cos z

where z here is the zenith distance.

sin b = sin (90 deg - Lat)

sin c = sin z

Let's say we want to find the declination of the star if the observer's latitude is 45 degrees N, the azimuth of the star is measured to be 60 degrees, and its zenith distance z = 30 degrees. Then one would solve for cos a:

cos a = = cos (90 deg - decl.)=

cos (90 deg - Lat) cos z + sin (90 deg - Lat) sin z cos (A)

cos (90 deg - decl.)=

cos (90 - 45) cos 30 + sin (90 - 45) sin 30 cos 60


cos (90 deg - decl.)= cos (45) cos 30 + sin (45) sin 30 cos 60

We know, or can use tables or calculator to find:

cos 45 =  Ö2/ 2

cos 30 = Ö3/ 2

sin 45 = Ö2/ 2

sin 30 = ½

cos 60 = ½


cos (90 deg - decl.)= {(Ö2/ 2 )(Ö3/ 2)} + {Ö2/ 2} (½) (½)

cos (90 deg - decl.)= Ö6/ 4 + Ö2/ 8

= {2 Ö6 +  Ö2/ 8)

cos (90 deg - decl.)= 0.789

arc cos (90 deg - decl.)= 37.9 deg


decl. = 90 deg - 37.9 deg = 52.1 deg

Or, in more technical terms:

decl. (star) = + 52.1 degrees

As can be seen with this example, once the basic geometry of the sky is grasped, relatively straightforward calculations can be used to obtain various astronomical angular measures as well as coordinates.

The Real Reason The Labor Participation Rate Is Lower

The Right's ideologues have many "footballs" they love to kick around in the culture wars in the U.S. of A., but one of their favorites is the "labor participation rate".  To read some of the hogswill in assorted economic columns - especially as it hit 63.0 percent in 2017, you'd think the whole country had turned into lazy bums who no longer want to work. But this misreads the statistic in a major way.

First let's get into the nitty gritty of this stat.

Here's how to calculate the Labor Force Participation Rate.
LFPR = Labor Force / Civilian Non-Institutionalized Population 
where the Labor Force = Employed + Unemployed
To calculate the formula correctly, you must first understand the underlying definitions outlined by the Bureau of Labor Statistics.
Civilian Non-institutional Population = Everyone living in the U.S. who is 16 or older MINUS inmates of institutions such as prisons, nursing homes and mental hospitals and MINUS those on active duty in the Armed Forces.
Labor Force =  Everyone who is classified as either Employed or Unemployed.
Employed =   Anyone aged 16+ in the civilian non-institutional population who worked in the last week. That means they worked an hour or more as paid employees or 15 hours or more as unpaid workers in a family-owned business or farm. It also includes those who had jobs or businesses, but didn't work that week because they were on vacation, sick, were on maternity or paternity leave, on strike, were in training, or had some other family or personal reasons they didn't work.

(Each worker is counted once, even if s/he held two or more jobs. Volunteer work doesn't count nor work at home.)

Unemployed =  Those age 16 or more who weren't employed, but were available for work and actively looked for a job within the past four weeks.

Note here: people who would LIKE to work, but haven't actually gotten out, pounded the pavement and LOOKED for work, aren't counted.  They are counted in the population, however, which means the more of them, the lower the calculated labor participation rate.   This also includes those who have stopped looking for work entirely because they don't believe there are any jobs for them, and the BLS calls these discouraged workers."

Obviously, not all of these folks are bums, and that includes workers that become ill - say from severe diabetes or leukemia and then need to go onto Social Security disability. In the March 4 Denver Post article, 'Fewer Americans Working But Why?', we learn for example that "the share of Americans working dropped about 6.8 million from 1999 to 2016."   Did all those people become "lazy bums" on welfare or Social Security disability? No, as the article explains:

"Between 50 to 70 percent of the decline was due to an aging population"  which is reinforced by another WSJ piece from February 15 (p. A17) 'As Boomers Go Gray, Even 2% Growth Will Be Hard To Sustain' noting: 

"Slower growth is less the fault of Trump than his generation. Forty percent of the people born in 1946 have left the workforce."

But let's be reasonable here. "Blame" cannot be part of the nomenclature at all, because at some point every human - at least in the US of A  - is going to want to retire and halt the grind. (Retired people aren't counted among the work force, but are counted in the population, hence the larger the number of retired the lower the LFPR.)  Especially those members of the graying generation who are already having to fend off ageism in even finding decent jobs -  by which I mean jobs paying enough to make the rent - and yeah, save for retirement. So you cannot "blame" oldsters for the leaving the workforce, say when they hit the big Seven Oh. You can't even blame those who may choose to leave at 55 or 60 if they have enough money saved for retirement to make it.  You may be pissed that you can't do it, but you can't blame them for doing so.

Anyway, this still leaves some 30- 50 percent of the decreased LFPR to account for - according to the D. Post piece. Thanks to robust research by Katharine Abraham and Melissa Kearney of the University of Maryland, some answers are forthcoming. Well, at least to the extent we now know what isn't driving the LFPR downward.   In a draft paper released by the National Bureau for Economic Research last month Abraham and Kearney found that trade with China and automation are responsible for millions of missing workers.  (And missing jobs).

Other typical scapegoats of the Right's scolds, e.g. immigrants, food stamps and "Obamacare" - didn't "move the needle".  Other related findings:

- Automation cost more jobs than it created and "robots likely cost the economy 1.4 million fewer workers"

- The number of people going onto Social Security Disability doubled from 1999 to 2016, from 4.9 million to 8.8 million.  The population did age, but that increase was still "1.64 million more people than there should have been", i.e. had rates remained steady for each age group.

VA Benefits:

The two economists estimated that 0.15 million more people didn't participate in work because of the expansion of VA disability insurance. (Between 2000 and 2013 the share of vets receiving such benefits rose from 9 percent to 18 percent).

One last factor was deemed a likely contributor to the lower labor participation rate: the inability to move from one location to another  to find work as was generally done in the past. The reason is that the home is usually Americans' biggest investment and it simply may not be possible to move from A to B if one's home either can't be sold for the price assessed, or there are no buyers. Then, it would take a real leap of faith to just move to  a new locale  without a firm job offer even lined up.

Beyond all the labor participation rate kerfuffle, what those like Jason Furman (WSJ piece) are really getting at is how difficult it will be to attain even a 3 percent growth rate and sustain it.  Furman, for example, points to last year's growth rate (2.5 %) which while greater than previous is still an aberration. It is an aberration because "more than half of it is based on cyclical factors".  These "have little or nothing left to contribute" since we're at or near full employment. (Which again makes one wonder why all the fuss about a low labor participation rate. Do the wonks really want it to become even tighter and possibly fuel inflation?)

Furman doesn't see the growth rate over the next 5-10 year getting much more than the pedestrian 5- 10 %.   He lays blame on all of us retired boomers, as well as needing  "bigger  productivity improvements".   I already dealt with how the latter can be achieved by ditching the GDP e.g.


"If the GDP is in error or doesn't measure what is really needed, then the labor productivity will be off too. "

How to easily improve productivity even with all the retirees? Simply include home work into the productivity equation.  For example, a 2015 Forbes article highlighted how 40 million family caregivers in the U.S. are putting their own careers on hold to provide unpaid care — sometimes for decades.   The estimated  total value of the care has been put at nearly $1 trillion. This isn't reckoned into the GDP but IF it were,  the labor productivity cited in the WSJ would surely be much higher in the years since 2007 - maybe even double or (1.2%) x 2  2.4 %. Which would then exceed the rate cited since 1947.

What to use in place of GDP? The Index of Sustainable Economic Welfare which was first proposed by Eco-economist Herman Daly of the University of Maryland. is a prime alternative  Daly's point was that the GDP was too artificial and narrow an indicator of economic health. He argued that if one incorporated all the "externalities" usually dismissed or ignored by standard economic models, people would be more parsimonious in how they consume which would yield a better world.

But will the economist wonks take note and agree? That remains to be seen, but I am not optimistic. If they did agree they'd be out of work!

Wednesday, March 14, 2018

In Memoriam: Stephen Hawking

Professor Hawking’s insights shaped modern cosmology and inspired global audiences in the millions.
Perhaps the greatest cosmologist ever - Stephen Hawking - died  at 76.

Stephen Hawking, one of the the brightest stars in the firmament of science, whose insights into modern cosmology inspired millions, has died aged 76.  Hawking's family released a statement in the early hours of Wednesday morning confirming his death at his home in Cambridge.

Hawking’s children, Lucy, Robert and Tim said in a statement: “We are deeply saddened that our beloved father passed away today.He was a great scientist and an extraordinary man whose work and legacy will live on for many years. His courage and persistence with his brilliance and humor inspired people across the world."
He once said: ‘It would not be much of a universe if it wasn’t home to the people you love.’ We will miss him for ever.”
Well all of us will miss him, especially those of us who have written books that promoted his ideas, such as the 'boundary free cosmos" as well as imaginary time.  Indeed, anyone who'e been involved in astronomy at any level - even if they haven't read his ground breaking book, 'A Brief History of Time.   This was the work, not some abstract theoretical paper, that rocketed him to fame.  
Published for the first time in 1988, the title made the Guinness Book of Records after it stayed on the London Sunday Times bestsellers list for an unprecedented 237 weeks. It sold 10 million copies and was translated into 40 different languages. 

In 1974 Hawking drew on quantum theory to declare that stellar black holes - i.e. collapsed from large mass stars- were not the only type. There should also be "mini" or quantum scale  holes capable of emitting heat and eventually popping out of existence. For normal black holes, the process is not a fast one,  taking longer than the age of the universe for a black hole to terminate.. But near the ends of their lives, mini-black holes release heat at a spectacular rate, eventually exploding with the energy of a million one-megaton hydrogen bombs. Miniature black holes dot the universe, Hawking said, each as heavy as a billion tonnes, but no larger than a proton.
His proposal that black holes radiate heat stirred up one of the most passionate debates in modern cosmology. Hawking argued that if a black hole could evaporate into a bath of radiation, all the information that fell inside over its lifetime would be lost forever. It contradicted one of the most basic laws of quantum mechanics, and plenty of physicists disagreed.

More recently, Prof. Hawking achieved even more popular renown in the Oscar-nominated movie,  The Theory of Everything, in which Brit Eddie Redmayne played the lead role and won Best Actor Oscar. Hawking also appeared on The Simpsons and played poker with Einstein and Newton on Star Trek: The Next Generation. He  also delivered  memorable put-downs of  the insufferable geekazoid,  Sheldon Cooper, on The Big Bang Theory.
While it is true that Prof. Hawking never won a Nobel Prize, that should not diminish the respect and gratitude those of us who've worked in space science, astronomy or cosmology have for him. In that regard, I leave readers with the following links to previous posts I've written to do with Stephen's various forays:

 See also this interesting Hawking lecture on 'how to escape from a black hole':
We will surely miss your wit and intellect, Professor Hawking!

See also: