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Thursday, July 21, 2011

Book review: “At Home: A short history of Private Life” by Bill Bryson

book_at_home_ppbkI’ve been on holiday for a week, this has meant a lot of reading! Next up is “At Home: A Short History of Private Life” by Bill Bryson. A thick book arranged thematically around the rooms in Bryson’s house, a rectory in Norfolk. The links between the various rooms and the topics discussed are sometimes tenuous, such as the one between the cellar and the Erie Canal.

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Sunday, July 17, 2011

Lead mining in the Yorkshire Dales

Bunting level: building, level entrance and hush

On a recent trip to the Yorkshire Dales we came across the remnants of lead mining; as with many things in the field these are blank discoveries with no indication of what they mean at the site. A very long time ago I did an OA level in geology, and I seem to have inherited an interest in industrial archaeology, so I resolved to find out more...

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2, Nurse Cherry's Cottage**I’ve moved my blog to, you can find this post here**

In a change from usual service we went to the Yorkshire Dales rather than the Lake District for our summer holiday, this is the land of my father - whose family lived, and still live for the most part around the southern edge of the Dales. We stayed in a cottage in Reeth (2, Nurse Cherry's Cottages), recently built but in the old style. The advantage of this are that it's spacious and the plumbing was not added as an afterthought. I think the cottage was advertised as sleeping up to four people, with two bathrooms and a downstairs toilet it would take 6 pretty comfortably. We are only two, so had plenty of room. We arrived in a downpour but for the rest of the week the weather was pretty good. Reeth is a small village which was once a centre for mining and farming but now is a centre for tourism - lying in the Yorkshire Dales and on the coast to coast path. It's dominated by a large central green, although there are older buildings many are quite modern but built in the same style as the older, using the local stone.

Day 1

A pleasant walk up Arkengarthdale to Langthwaite, and back along Fremington Edge Top. The walk outwards is through pasture and many narrow styles in stone walls with little gates to prevent sheep escaping. Shortly before Langthwaite there is a footbridge across the river which takes you to a short walk through woodland before climbing up through old lead mine workings up onto Fremington Edge Top. We took the route which avoided the hamlet of Booze, considering that it was so small that it was unlikely to have a good quality sign to picture ourselves besides. Nearby is Blea Barf, and at the top of the valley on the road over into Hawse is Lovely Seat, one can't help thinking that when the Ordnance Survey visited the locals had some fun.

The walk along Fremington Edge Top is dead straight along the side of the wall. I wonder whether these walls date to the time of the old iron fence posts in the Lake District - perhaps relating to some Enclosures Act. The wall runs along the edge of wild moorland to the north and after a pleasant, if not a little windswept walk you drop back down towards Reeth.


Day 2

A route from The Green Book starting at Gunnerside, heading to Muker then up Upper Swaledale towards Keld and then back towards Muker via the Pennine Way and so along the river back to Gunnerside. Highpoints were the waterfalls at the foot of Swinner Gill and Kisdon Force. Photographers will know there is a knack to photographing waterfalls such that the water appears milky rather than frozen in time by a short exposure. The problem is this requires long exposures (about 1/2 second) and this is a bit tricky to do without a tripod - a handy rock or handrail must suffice instead. Crackpot Hall was also interesting, the term Hall is rather grandiose but the views down Swaledale were spectacular. Much birdlife to be seen including a greater spotted woodpecker, dipper, spotted flycatcher, grey wagtail, plover - no photos of these since that requires patience, speedy reactions and so forth. Lapwings all over the place.

Kisdon Force

Day 3

A more restful day today: we headed down to Harrogate and the RHS Harlow Carr garden. This is horticulture, so I'll leave the details to The Inelegant Gardener. It's a fairly lengthy drive down to Harrogate from Reeth - a little under an hour and a half. My abiding memory will be of coffee and Fat Rascal in Betty's Tea Rooms, attached to the gardens but not providing a route in or out. After a morning at Harlow Carr we headed back home via Richmond: a rather smart little town on a steep hillside with a huge castle (and more waterfalls). The Market Square would be spectacular if it weren't for a flotsam of cars which spoil any photo. Sharon and I both seem to suffer from a list which prevents the photography of buildings without post-processing. A balanced diet today of Fat Rascal, sausage roll and icecream, available from the icecream shop in Reeth a mere 100 yards from our door (via shortcut).

Richmond Castle

Day 4

Back to walking, this time one of my own devising. Starting from Gunnerside we headed up Gunnerside Beck until we reached the lead workings at Melbecks Moor. There a several sets of ruined buildings and mine tailings as you head up the valley. After climbing up through the surface workings we got onto the moor top where were visible grouse, grouse grit stations (where they can pick up grit for their gizzards) and grouse butts from where they can be shot at. You have to get pretty close to grouse before they break cover. Finally, we dropped down into the valley where we got a little lost (and quite badly nettled) trying to find the path through Rowleth Wood. Once on the path through the wood, which is narrow and overgrown, we were further nettled and as I write now a couple of hours later my legs are still tingling from the knees down.

After our walk we visited the Swaledale Museum, which although small was highly informative on the local mining industry - a subject I shall return to in another blog post.

Stonebreaker, with Sharon in background

Day 5

Over to Wensleydale for our walk today (from the Green Book), from Bainbridge up to Semer Water (a rare natural lake in the Dales) and then onwards and back via the Roman Road. The Roman Road was very straight, and as usual somewhat disappointing - it requires a great deal of imagination to call up the requisite Roman soldiers. The weather was rather better than yesterday which was overcast and prone to the odd shower; today it is a little cool out of the sun.

Wensleydale from the Roman Road

Day 6

Final day, today we went back to Wensleydale for a walk from the Green Book starting at Aysgarth Falls and taking in Bolton Castle. The Falls are a bit of a disappointment, the approved viewing locations are a little distant from the falls and are rather confined. Richmond falls offer something similar, with slightly peaty-brown water cascading over flat slabs, but with much better access. Bolton Castle, on the other hand is rather impressive, visible on the valley side for many miles it is a solid, square chunk of masonry. It was built for Richard de Scrope in 1379, and is quite substantially intact.

Bolton Castle

The Yorkshire Dales are quite different from the Lake District: the peaks are less peaky, the valleys wider and more gentle, although the moors can be bleak when the wind blows and the clouds come down. There are also a lot of picturesque waterfalls, not in the style of the Lake District which tend to be frenzied plummets down ravines but cascades over broad rocky shelves. Villages like Hawes and Reeth can get quite busy as the day goes by but out walking we scarcely saw a soul. The stone walls are all pierced with small stone stiles, which have been the distinguishing feature of this holiday.

Stone Stile

More photos here.

Friday, July 15, 2011

Book review: “In defence of History” by R.J. Evans

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evansI've been interested in the history of science for some time, as a result of hanging around with historians on twitter I have been led to historiography - the study of history and its methods. This has brought me to "In Defence of History" by Richard J. Evans. It provides an opportunity to compare the ways of the historian with those of my area of science.
In his introduction Evans makes clear the book is a response to postmodernist criticism of historical practice. I was also amused to note that he cites a source as saying that historians were resistant to philosophising about their subject and criticism of their methods. As a scientist it sometimes feels as if other academic disciplines, such as philosophy and history, are on a crusade to "help" science with their criticism - this has never felt at all supportive or helpful. What this book makes clear is that one shouldn't lump all such outsiders into one hostile blob!
It becomes clear through the book that postmodernism is not really a single thing. The core is the idea that all things are text, and that an external, objective world is less relevant - this idea originated with linguists and philosophers who were relatively unconcerned with the external world. As a somewhat hostile outsider Evans probably does not provide the best introduction to postmodernism, although he does acknowledge that ideas from postmodernism have been useful in the study of history and historical study.
As a by-product of this defence Evans gives a clear survey of what history is and what it claims to do.
The book begins with a history of history: raising first pre-modern styles of history, such as the chronicle and the morality tale of Gibbon's "Decline and Fall of the Roman Empire". Leopold von Ranke is cited as the father of the modern method, that's to say the inspection of contemporary documents in the historical record using them to identify causes for historical events and "facts". Here the distinction is made between the primary sources and secondary sources. For Ranke the key subject of history was politics, a view that held sway for many year but more recently has been receding. The key to the historical method therefore is hunting down original documentation and reading it with a mind to its original purpose and the context of other documents of that period with a care not to be caught out by changes in language and unspoken purposes.
Evans also identifies the crisis in history following the First World War, a stark reminder to historians that predicting the future was tricky although Evans does not sign up to the idea that history is at all about predicting the future. There's an interesting parallel here between Toynbee's "A study of history" which tried explicitly to make laws of history for predicting the future and Asimov’s Foundation series of novels, which are based on precisely this idea. Predicting future events sets a high barrier for successful prediction, some fields of science face similar challenges such as in seismology - we can say an awful lot about earthquakes but exactly where and when are not amongst the things we can say. For these fields it's typical to talk about the probabilities of events and the statistics of large numbers of events.
One thing that struck me was the statement that history was a scientific, imaginative and literary exercise, the first two are things that a scientist would sign up to for their own field immediately, but literary? For sciences such as the one I trained in, physics, students are scarcely asked to string words together. Exam questions are largely a case of putting a sequence of calculations together. My own writing is a reflection of this lack of training.
At one point Evans spends time trying to motivate the idea that history is a science, this seems to me an empty discussion - once you've decided whether or not history is a science what are you going to do? Put on a labcoat?
Since Ranke's time history has diversified immensely with the increasing focus on non-political history such as social history and an appreciation of a wider range of themes , I find this liberating since my interest in history is primarily in "people like me", therefore social and scientific, rather than political.
In contrast to any scientific research I know the political beliefs, defined broadly to include race, gender and sexuality, have a strong bearing on historical research with fields driven to support currently political agendas and the political leanings of the researcher a subject of comment. The same goes for nationality with many European historians focused very much on their own nations and with a distorted view of their importance. It's very difficult to find parallels in scientific research, to stretch a point you can perhaps look at genetic and brain imaging studies of homosexuality. There is a degree to which there exist national styles of scientific research which have varied with place and time but this research driven by the political agendas of the researcher feels alien to a scientist.
When doing battle with the postmodernists the work of a scientist is easier than that of a historian, since ultimately the usefulness of science is measured by tangible outputs, by impact. If postmodernism increases tangible outputs then it is welcomed into the fold, if it doesn't (and I don't believe it does) then it isn't. Science is tied down by reality which is always there for a return visit, with new methods, in case of dispute. History on the other hand is always flowing past, with no chance of return.
An interesting note on style is the forthright criticism of other historians through the book, and also in the afterword where he addresses his critics in detail and at length. This type of writing is rarely seen in science, that's not to say the thoughts do not exist just that such discussions are left to the bar, or other informal locations.
I found this book immensely thought provoking because it describes the inner workings of history from the point of view of a practioner, making a striking contrast with my own workings as a scientist.

Wednesday, July 06, 2011

The Two Cultures

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It feels that there are two cultures growing up in the world of work, that of the public and the private sectors. If you believe reports in the news, public sector workers have gold-plated pensions and vast salaries for which they do very little, and the private sector is filled with the venial moneygrabbers who can provide no service to the public, and are actively intent on harming them.

I worked in the almost-public university sector, and now in the private sector – albeit in a very large company. The similarities are quite striking: both are subjected to continual change as the result of the appointment of a new ruling clique, and often operate in Byzantine bureaucratic systems.

These days, in the private sector, my tenure is clearly not secure and never has been, despite continuing success the number of people employed in my company has decreased by over a half since 2000. I receive a bonus, or variable-pay, it is variable and it is not pensionable. 

Last week many public sector workers were on strike over their pensions.

Comparisons with private sector pensions miss the point: in the public sector 90% of full-time workers have a pension, in the private sector only 43% of the full-time workforce have a pension [source]. The glib answer to this is that we should attempt to improve the pensions of all workers. However, we should understand why pensions are not a given in the private sector.  

Consider the nature of the organisations involved: the UK government has been around for hundreds of years, and we can anticipate it will do so similarly for hundreds of years. It also has a good credit record, if we are owed money by the government there is a good chance that we’ll get because at any time the government has a sizeable tax base on which it can call. As employees of the government we can expect substantial job security. A pension plan based on 1/80ths of income accrued per year actually seems a plausible bet: you can still expect to serve a substantial fraction of that with one public employer. It’s not the same in the private sector.

For most companies 40 years is an unimaginable period of time, as it is for their employees. In 40 years many successful companies will have lived out their lives, only a few such as the one I belong to, last longer. In the recent past private pension funds have collapsed leaving their members with nothing. As a university lecturer I could quite reasonably look forward to being employed as a university lecturer for the rest of my working life. As an industrial research scientist my time horizon is about 5 years, and actually it is entirely plausible that we will all be called to a meeting tomorrow to discover that the site I work on is to be closed.

That’s the deal for big organisations, public and private but there is a third group: Have you tried to get a plumber, or similar skilled, self-employed worker recently? If you have you’ll have found that they’re remarkably available at the moment, that’s because they have no work and when they have no work they don’t get paid. The same is true for many small businesses and self-employed people. It’s not like my job, or any job in the public sector where there may be a pay freeze for for a few years. For these people recession and a drop in the GDP doesn’t just mean a pay freeze, it means a substantial drop in income – that’s what a drop in GDP is, it really means that a whole load of people are getting noticeably less than they did the previous year. The recent recession in the UK led to a drop in GDP of around 5%. The effects on me, in a big company, and those in the public sector are relatively small, so the impact on this other group are larger than the headline.

Meanwhile the company I work for is attempting changes to our pension scheme: a few years ago the final salary scheme was closed to new entrants, this year they have proposed to close the scheme for current members. The company’s stated policy is to go towards a defined contributions scheme, although that hasn’t happened yet. For people like me this means an expected loss in the value of their pension of around 20%. So, despite some misgivings as to the use to which they put their political fund (of which I will attempt to opt-out), I have joined the union.

Power to the people!

Sunday, July 03, 2011

Computational Photography


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Lytro, Inc, a technology spin-off company founded by Ren Ng, have been in the news recently with their announcement of a re-focusable camera: take one “image”, and change where the focal plane lies after the fact. This is illustrated in the images above, generated from a single shot from the prototype camera. As you move from left to right across this sequence you can see the focus shifting from the front left of image to back right.I saw this work a few years ago at the mighty SIGGRAPH conference, it comes out of a relatively new field of “computational photography”.

All photography is computational to a degree. In the past the computation was done using lenses and chemicals, different chemical mixes and processing times led to different colour effects in the final image. Nowadays we can do things digitally, or in new combinations of physical and digital.

These days your digital camera will already be doing significant computation on any image. The CCD sensor in a camera is fundamentally a photon-counting device – it doesn’t know anything about colour. Colour is obtained by putting a Bayer mask over the sensor, a cunning array of red, green and blue filters. It requires computation to unravel the effect of this filter array to make a colour image. Your camera will also make a white balance correction to take account of lighting colour. Finally, the manufacturer may apply image sharpening and colour enhancement, since colour is a remarkably complex thing there are a range of choices about how to present measured colours. These days compact cameras often come with face recognition, a further level of computation.

The Lytro system works by placing a microlens array in the optical train, the prototype device (described here) used a 296x296 array of lenses focusing onto a 16 million pixel medium format CCD chip, just short 40mmx40mm in size. The array of microlenses means means that for each pixel on the sensor you can work out the direction in which it was travelling, rather than just where it landed. For this reason this type of photography is sometimes called 4D or light-field photography. The 4 dimensions are the 2 dimensions locating where on the sensor the photon lands, and the direction in which it travels, described by another two dimensions. Once you have this truckload of data you can start doing neat tricks, such as changing the aperture and focal position of the displayed image, you can even shift the image viewpoint.

As well as refocusing there are also potentially benefits in being able to take images before accurate autofocus is achieved and then using computation to recover a focused image.

The work leading to Lytro was done by Ren Ng in Marc Levoy’s group at Stanford, home of the Stanford Multi-Camera Array: dispense with all that fiddly microlens stuff: just strap together 100 separate digital video cameras! This area can also result in terrible things being done to innocent cameras, for example in this work on deblurring images by fluttering the shutter, half a camera has been hacked off! Those involved have recognized this propensity and created the FrankenCamera.

Another example of computational photography is in high dynamic range imaging, normal digital images are acquired in a limited dynamic range: the ratio of the brightest thing they can show to the darkest thing they can show in a single image. The way around this is to take multiple images with different exposures and then combine together. This seems to lead, rather often, to some rather “over cooked” shots. However, this is a function of taste, fundamentally there is nothing wrong with this technique. The reason that such processing occurs is that although we can capture very high dynamic range images, displaying them is tricky so we have to look for techniques to squish the range down for viewing. There’s more on high dynamic range imaging here on the Cambridge in Colour website, which I recommend for good descriptions of all manner of things relating to photography.

I’m not sure whether the Lytro camera will be a commercial success. Users of mass market cameras are not typically using the type of depth-of-field effect shown at the top of the post (and repeated ad nauseum on the Lytro website). However, the system does offer other benefits, and it may be that ultimately it ends up in cameras without us really being aware of it. It’s possible Lytro will never make a camera, but instead license the technology to the big players like Canon, Panasonic or Nikon. As it stands we are part way through the journey from research demo to product.

Tuesday, June 28, 2011

Universities and knowledge

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The Higher Education White Paper is published today, in common with all other commentators in this area I have not read it either. One thing which seems to have attracted comment is the idea that there should be a market in higher education. The academics don’t seem to approve.

But knowledge doesn’t belong to universities. Universities provide qualifications, accreditation, and they provide personalised teaching.

For many students, such as myself 20 years ago, a university education was a given: it was the middle class way of easing myself out of the parental home and the gateway to the career I have now – first as an academic and now as an industrial research scientist. It was available to a relatively small fraction of the population. Things have changed now, increasingly university is seen as the gateway to most careers. Students do not go to university for the love of knowledge, they go because they must to get the careers they want. Pragmatically many careers do not require three years of post-18 education but we are manoeuvring ourselves in to a position where we say they must.

Students will no doubt see themselves in a market – even before this white paper they were being asked to commit significant future income in paying for three years of education, they are foregoing three years of paying work for the promise of a better future. If I were a student I’d be a bit peeved that the university sector were not at least showing willing in making that burden lighter.

Universities don’t give us knowledge – that’s down to us as individuals to hunt out, universities give us the tools to do that and the bit of paper that says we can do that.

Book review: Map of a Nation

**I’ve moved my blog to , this post can be found here**

ordnance"Map of a Nation" by Rachel Hewitt is the story of the Ordnance Survey from its conception following the Jacobite Uprising in Scotland in 1745 to the completion of the First Series maps in 1870. As such it interlinks heavily with previous posts I have made concerning the French meridian survey, Maskelyne's measurements of the weight of the earth at Schiehallion, Joseph Banks at the Royal Society, William Smith's geological map of Britain and Gerard Mercator.

The core of the Ordnance Survey's work was the Triangulation Survey, the construction of a set of triangles across the landscape made by observing the angles between landmarks (or triangulation points) ultimately converted to distances. This process had been invented in the 16th century, however it had been slow to catch on since it was slow and required specialist equipment and knowledge. Chromatic abberration in telescopes was also a factor - if your target is surrounded with multi-colour shadows - which one do you pick to measure? The triangles are large, up to tens of miles along a side, so within these triangles the Interior Survey was made which details the actual features on the ground - tied down by the overarching Triangulation Survey.

A second component of this survey is the baseline measurement - a precise measurement of the length of one side of one triangle made, to put it crudely, by placing rulers end to end over a straight between the terminal triangulation points.

The Triangulation Survey is in contrast to "route" or "transverse" surveys which measure distances along roads by means of a surveyor's wheel, note significant points along the roadside. There is scope for errors in location to propagate. Some idea of the problem can be gained from this 1734 map showing an overlay of six "pre-triangulation" maps of Scotland, the coastline is all over the place – with discrepancies of 20 miles or so in places.

The motivation for the Ordnance Survey mapping is complex. Its origins were with David Watson in the poorly mapped Scotland of the early part of the 18th century, and the Board of Ordnance – a branch of the military concerned with logistics. There was also a degree of competition with the French, who had completed their triangulation survey for the Carte de Cassini and were in the process of conducting the meridian survey to define the metre. The survey of England and Wales was completed after the Irish Triangulation and after the Great Trigonometric Survey of India - both the result of more pressing military and administrative needs. As the survey developed in England more and more uses were found for it. Indeed late in the process the Poor Law Commission were demanding maps of even higher resolution than those the Ordnance Survey initially proved, in order to provide better sanitation in cities.

The Survey captured popular imagination, the measurements of the baseline at Hounslow Heath were a popular attraction. This quantitative surveying was also in the spirit of the Enlightenment. There was significant involvement of the Royal Society via its president, Joseph Banks, and reports on progress were regularly published through the Society. Over the years after the foundation of the Ordnance Survey in 1791 accurate surveying for canals and railways was to become very important. In the period before the founding of the Ordnance Survey surveying was a skill, related to mathematics, which a gentleman was supposed to possess and perhaps apply to establishing the contents of his estate.

Borda's repeating circle, used in the French meridian survey to measure angles, found its counterpart in Jesse Ramsden's "Great Theodolite", a delicate instrument 3 feet across and weighing 200lbs. The interaction with the French through the surveying of Britain is intriguing. Prior to the French Revolution a joint triangulation survey had been conducted to establish exactly the distance between the Paris and Greenwich meridians, with the two instruments pitted against each other. There was only a 7 foot discrepancy in the 26 miles the two teams measured by triangulation between Dover and Calais. In 1817, less than two years after the Battle of Waterloo a Frenchman, Jean-Baptiste Biot, was in the Shetlands with an English survey team extending the meridian measurements in the United Kingdom.

The accuracy achieved in the survey was impressive, only one baseline measurement is absolutely required to convert the angular distances in the triangulation survey into distances but typically other baselines are measured as a check. The primary baseline for the Triangulation Survey was measured at Hounslow Heath, a second baseline measured at Romney Marsh showed a discrepancy of only 4.5 inches in 28532.92 feet, a further baseline measured at Lough Foyle, in Northern Ireland found a discrepancy of less than 5 inches in 41,640.8873 feet.

The leaders of the Ordnance Survey were somewhat prone to distraction by the terrain they surveyed across, William Roy, for example, wrote on the Roman antiquities of Scotland. Whilst Thomas Colby started on a rather large survey of the life and history of Ireland. Alongside these real distractions were the more practical problems of the naming of places: toponymy, particularly difficult in Wales and Ireland where the surveyors did not share the language of the natives.

Overall a fine book containing a blend of the characters involved in the process, the context of the time, the technical details and an obvious passion for maps.


In writing this blog post I came across some interesting resources:

Sunday, June 26, 2011

The Weekly Rage

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Every week I listen to the Sunday programme on Radio 4, largely through inertia. Most weeks it manages to wind me up. I was a bit worried that I may be repeating myself here, so regular is the rage that I thought I must have written about it before. It turns out I have, but on a different topic.

The specific cause of my ire this week is the Church of England, the Equalities act and the inadmissibility of gay bishops. Forced by the Equality Act 2010 the Church has sought legal advice on how it should treat its gay clergy, it turns out they think that they may be obliged to accept gay bishops but that they can demand that they are celibate. You can read the BBC report here.

Why should this concern me, as a British atheist? Several reasons:

  • the Church of England is an established church, it takes (unelected) part in our legislation through the Lords Spiritual, it has a special position in teaching our children;
  • the Church of England claims moral authority, it specifically claims that it’s views on morality are superior to mine because they are faith-based. See the Bishop of Oxford’s comments this week on the Today programme;
  • I am ethnically Christian and English, so their position reflects badly on me;
  • the church’s position puts us all on shaky ground when we argue against inequality in other communities.

The Church could take a principled position that any group should be able to follow it’s faith: that the BNP should be allowed to exclude non-Caucasians from their number, for example. It could take the principled position that it should be subject to the same laws as the rest of us, without exemptions. It choses to do neither of these things, it choses instead to lobby for exemptions from the law and work out the minimum they can get away with in complying with that watered-down law.

What is the Church trying to tell us through this position? That the gays are OK, but not for them and not for positions of power?

Can you imagine a company, such as the one that I work for, demanding of it’s employee’s that they not only reveal their sexual orientation but also their sexual activity and if they confessed to the wrong sort of sexual activity they should be denied promotion?