Marty Nemko's Career Tips: Surviving Today's Job Market
Marty Nemko's Career Tips: Surviving Today's Job Market from Commonwealth Club and Commonwealth Club on FORA.tv
Saturday, August 25, 2012
Marty Nemko's Career Tips: Surviving Today's Job Market
Marty Nemko's Career Tips: Surviving Today's Job Market from Commonwealth Club and Commonwealth Club on FORA.tv
Wednesday, August 22, 2012
Family trees: Tracing the world's ancestor
Family trees: Tracing the world's ancestor
A
question one Radio 4 listener asked about the bloodline between Jesus
and King David raised a wider genealogical issue. How many generations
does it take before someone alive today is the ancestor of everyone on
the planet?
Listeners to the More or Less programme on Radio 4 have been
challenging me to answer any fiendish question they can throw at me. A question about Jesus's genealogy was rather interesting and the answer has astounding ramifications.
The Bible says Jesus was a descendant of King David. But with 1,000 years between them, and since King David's son Solomon was said to have had about 1,000 wives and mistresses, couldn't many of Jesus's peers in Holy Land have claimed the same royal ancestor?
Theory tells us that not only would all of Jesus's contemporaries be descended from King David, but that this would probably be the case even if Solomon had been into monogamy.
We can make this sort of prediction because over the past 15 years or so, these ideas have been studied as part of the research into understanding patterns in our own genome.
Continue reading the main story
Yan Wong is an evolutionary biologist specialising in computer and mathematical modelling of evolutionary genetics.
He is a presenter of the BBC One science programme Bang Goes The Theory and a contributor to More or Less.
Who is Yan Wong?
He is a presenter of the BBC One science programme Bang Goes The Theory and a contributor to More or Less.
The most successful approach has
been to go backwards in time, taking a sample of people and imagining
the patterns of inheritance in their ancestral family tree.
When applied to the question of who is descended from whom, the results can surprise even the professionals. That's because geneticists normally study biological information - DNA - that people inherit from just one of their parents.
Just like a surname, or the male lines of descent quoted in the Bible, these generate lineages that shrink or expand rather slowly. That's why we expect the proportion of Smiths in the phone-book to fluctuate only a little from decade to decade.
The surprise comes if we look at inheritance from both parents. Here, the numbers change drastically as the generations go by. For instance, we have two parents, four grandparents, eight great-grandparents, and so on.
Each generation back, we multiply the number by two. This leads to what is called an exponential increase: 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024 and so on.
It's not long before we hit huge numbers. Take the specific case of Jesus and King David.
The number of generations between them is at least 35. Luke lists 42 generations down the male line, and Matthew gives an incomplete list of 27.
Jesus Christ would have had more than 34 billion potential ancestors
So back in the time of David, Jesus would have had at least 2 x 2 x 2 x 2 (35 times); in other words 2^35 - or more than 34 billion potential ancestors. That's far more than the total population of the world, of course.
This is a good illustration of what's been called the "genealogical paradox".
Continue reading the main story
"The one thing that stands a chance of scuppering our
calculations is if the population is split into isolated groups," says
Yan Wong.
"However, to be considered separate, these groups need to basically never interbreed with each other.
"To quote one of the papers on this subject, 'substantial forms of population subdivision can still be compatible with very recent common ancestors'. (Rohde et al., 2004).
"In fact, even using current DNA studies, you can almost always detect distant shared relatives between distinct human populations (Henn et al., 2012)."
What about isolated communities?
"However, to be considered separate, these groups need to basically never interbreed with each other.
"To quote one of the papers on this subject, 'substantial forms of population subdivision can still be compatible with very recent common ancestors'. (Rohde et al., 2004).
"In fact, even using current DNA studies, you can almost always detect distant shared relatives between distinct human populations (Henn et al., 2012)."
In short, we seem to have too
many ancestors. The solution is that we have to take inbreeding into
account. Many of these ancestors are duplicates; the same person can
found through multiple routes in the family tree.
You are unlikely to be the product of inbreeding between
recent ancestors. So initially, your increase in ancestors will indeed
be almost exponential. But as your family tree increases to thousands upon thousands, you will inevitably find many obscure branches that have interbred. That's when the numbers start tailing off.
Even so, by that time, you will have collected a large number of people in your ancestry. So it's not surprising that any two people in any one country probably won't need to go back many generations before finding a common ancestor.
More specifically, imagine the simplest case of a population of a constant size - say a million (the approximate size of the Holy Land at the time of Jesus).
If people in this population meet and breed at random, it turns out that you only need to go back an average of 20 generations before you find an individual who is a common ancestor of everyone in the population.
If you go back on average 1.77 times further again (35 generations) everyone in the population will have exactly the same set of common ancestors (although they will be related, of course, through different routes in all the different family trees).
Advances in DNA allow us to detect shared genetic ancestry
Apply that to the case of King David. According to this model, he would be a common ancestor of the whole population of the Holy Land somewhere between 20 and 35 generations after his life. That's even without Solomon sowing his seed so widely.
That's why everyone alive in the Holy Land at the time of Jesus would have been able to claim David for an ancestor.
Reductions in population caused by events such as the Assyrian invasions will have produced more inbred family trees, and shortened the number of generations needed to reach a common ancestry.
Continue reading the main story
More or Less: Behind the stats
Listen to More or Less on BBC Radio 4 and the World Service, or download the free podcast
What about the wider
ramifications? A single immigrant who breeds into a population has
roughly 80% chance of becoming a common ancestor. A single interbreeding
event in the distant past will probably, therefore, graft the
immigrant's family tree onto that of the native population. That makes
it very likely that King David is the direct ancestor of the populations
of many other countries too.
How far do we have to go back to find the most recent common
ancestor of all humans alive today? Again, estimates are remarkably
short. Even taking account of distant isolation and local inbreeding,
the quoted figures are 100 or so generations in the past: a mere 3,000
years ago. And one can, of course, project this model into the future, too. The maths tells us that in 3,000 years someone alive today will be the common ancestor of all humanity.
A few thousand years after that, 80% of us (those who leave children who in turn leave children, and so on) will be ancestors of all humanity. What an inheritance!
Source
Monday, August 20, 2012
How Americans view wealth and inequality
How Americans view wealth and inequality
Americans do not understand how wealth is distributed in their society
There
have been lots of questions and discussions recently about inequality
and economists often argue about what is the right level of inequality
to have in society.
But Mike Norton, professor at Harvard Business School, and I
decided to take a different path and we decided to ask people what
inequality they would want.Now, there are lots of ways to ask this question and we used the philosopher John Rawls.
Rawls said that "a just society is a society that if you knew everything about it, you'd be willing to enter it in a random place". And it's really a beautiful definition.
He called it a veil of ignorance, because if you're very wealthy, you might want the wealthy people to have lots of money and the poor to have very little; and if you are very poor, you might want the poor to have more money and the wealthy to have less.
But in Rawls' definition, you don't know where you'll end up, you have to consider all the different options and therefore you have to think about what is good for society as a whole.
Incomprehension So, we took the American society and we asked people to imagine it divided into five buckets, the wealthiest 20%, the next 20%, the next, the next and the poorest 20%.
First of all, we asked people: how much wealth do you think is concentrated in each of those buckets?
It turns out people get it very wrong.
Continue reading the main story
“Start Quote
Even Americans understand that inequality is not a good idea and principle”
The reality is that the bottom
two buckets together, the bottom 40% of Americans, own 0.3% of the
wealth; 0.3%, almost nothing, whereas the top 20% own about 84% of the
wealth.
And people don't understand it. They don't understand how
much wealth the top have and in particular, they don't understand how
little the bottom has.But then we described to people Rawls' definition, the veil of ignorance, and the idea they could end up anywhere. And we said: What society would you like to create? How much wealth? How would you like to distribute the wealth?
And it turns out people created a society that is much more equal than any society on Earth. It was much more equal than Sweden.
Blind tasting In fact, when we did this experiment another way and we showed people two distributions of wealth, one based on the wealth distribution in the US and the other based on the wealth distribution that is more equal than Sweden, 92% of Americans picked the improved Swedish distribution.
So this suggests to me that when people take a step away from their own position and their own current state, and when people look at society in general terms, in abstract terms, Americans want a much more equal society.
How would you judge a wine if you didn't know where it came from or how much it cost?
And all this makes me wonder, how can it be that in our studies people seem to want such equal society but when you look at the political ideology, people don't seem to want that?
And I think it is a little bit like blind tasting of wine.
When you taste wine and you know the label and you know the price, you are going to be influenced by that. And when you are tasting wine in a blind way, now you don't have anything to base it on and you have to really use your senses.
I think the same thing happens with thoughts about just societies. When we are in the regular world, we are using our current position, our ideology and the labels that politicians give us, and they obscure reality and obscure what we really want.
But Rawls' definition really lets us strip all this away, lets us focus on what is really important and how people actually want something very different from what we have.
The question, of course, is how do we get people to think about this to a higher degree and how do we get them to act on that for a better future?
Dan Ariely is the James B Duke professor of psychology and behavioural economics at Duke University in North Carolina.
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