Thursday, June 22, 2017

Grey Catbird

New to my yard, as far as I can remember. I believe it is a grey catbird.





Monday, June 05, 2017

Acceleration in the rate of sea level rise

Some people are looking at sea level data and trying to fit a quadratic time curve to find the alleged acceleration in the rate of rise of sea level.   This doesn't work, and so they are very skeptical that the rate of rise of sea level has accelerated over the last century.

IMO, really they should be looking for piecewise linear fits, and a change in slope of the line segments. The point is that acceleration is simply a change in a rate; and nobody has claimed a constant acceleration in the rate of sea level rise. The rate of sea level rise has changed.

E.g., using data and the graphing utility at sealevel.info, here are three graphs.

Here is sea level data at Delfiziji, Netherlands from January1865 to December 2015.  The fitted line has a slope of 1.72 +/- 0.14 mm/year.

1/1865 - 12/2015 - 1.72 +/- 0.14 mm/yr
The web page also gives this:
Regressions
Linear:
  y = B + M·x
  y = 6797.353 + 1.716·x mm
Quadratic:
  y = B' + M·x + A·x²
  y = 6784.346 + 1.716·x + 0.00685·x² mm
where:
  Date range = 1865/1 to 2015/12
  x = (date - 1940.46(i.e., 1940/6)
  slope = M = 1.716 ±0.141 mm/yr
  acceleration = 2·A = 2×0.00685 = 0.01369 ±0.00722 mm/yr²
The posited constant acceleration is there, but extremely tiny and buried in the noise.

We now break the time series into two periods of about 75 years each, from January 1865 to December 1940; and January 1941 to December 2015.
The first period has the sea level rising at 1.31 +/- 0.37 mm/year.
The second period has the sea level rising at 2.25 +/- 0.43 mm/year.

Note that the confidence intervals don't overlap (i.e., 1.31 + 0.37 = 1.68; 2.25 - 0.43 = 1.82).
The rate of sea level rise has increased, ergo, accelerated.
1/1865-12/1940 - 1.31 +/- 0.37 mm/yr

1/1941 - 12/2015 - 2.25 +/- 0.43 mm/yr



Thursday, May 25, 2017

Government of India's credit rating


Moody's rates the Government of India at Baa3.  This is the lowest investment grade rating. Per Ashwath Damodaran at NYU this translates into a country risk premium of 3.13% (I suppose this means that the Government of India would pay interest on loans at 3.13% above the risk-free interest rate.)  The credit rating a notch above Baa3 is Baa2, and countries with that rating have a risk premium of 2.71%.

India's debt to GDP ratio in 2016 was 69.5%.  If India's credit rating improved from Baa3 to Baa2, and if all this debt could be refinanced at the lower interest rate,  the Government of India would save 0.3% of GDP in interest payments, that is about USD $6 billion a year.  Nothing to sneeze at.

Despite India's decent economic performance, Moody's chose not to upgrade India's credit rating (this from December 2016). 

The decision to maintain a positive outlook on the Baa3 rating rather than assigning a stable outlook to the rating at either Baa3 or Baa2 reflects two drivers:

- Economic and institutional reforms introduced since the positive outlook was assigned, and potentially forthcoming, continue to offer a reasonable expectation that India's growth will outperform that of its peers over the medium term and that further improvements in its macro-economic and institutional profile will be achieved.

- However, the reform effort to date has not yet achieved the conditions that would support an upgrade to Baa2, in particular in accelerating private investment to support high, stable growth, without which the government's debt burden -- a key constraint on the rating -- is likely to remain high for a sustained period.
Among the factors constraining the credit rating:
Meanwhile, on the revenue side, India's large low-income population limits the government's tax revenue base. At 20.9% of GDP in 2015, general government revenues were markedly lower than the 27.1% median for Baa-rated sovereigns. Although the implementation of GST and other measures aimed at enhancing income declarations and tax collection will help widen and boost revenues, the effects will only materialize over time and their magnitude is uncertain so far. 
I imagine the "other measures aimed at enhancing income declarations" include demonetization. 

A better credit rating would serve to attract more investment to India.  Widening the tax net in India and improving government finances is a high-stakes game.

Tuesday, May 16, 2017

Prehistoric migrations into South Asia

A new paper here, its abstract, and commentary from Rudradev on BRF:
A diffusion based study of population dynamics: Prehistoric migrations into South Asia
Mayank N. Vahia, Nisha Yadav, Uma Ladiwala, Deepak Mathur
Published: May 11, 2017
https://doi.org/10.1371/journal.pone.0176985

Saturday, April 29, 2017

Hard evidence on the emergence of patriarchy?

The May 2017 issue of the Scientific American has a story "Of Meat and Men: Ancient Bones may hold clues to the origin of male domination in society".  Following the breadcrumbs leads to this:

"Shifting diets and the rise of male-biased inequality on the Central Plains of China during Eastern Zhou"
Abstract

Farming domesticated millets, tending pigs, and hunting constituted the core of human subsistence strategies during Neolithic Yangshao (5000–2900 BC). Introduction of wheat and barley as well as the addition of domesticated herbivores during the Late Neolithic (∼2600–1900 BC) led to restructuring of ancient Chinese subsistence strategies. This study documents a dietary shift from indigenous millets to the newly introduced cereals in northcentral China during the Bronze Age Eastern Zhou Dynasty (771–221 BC) based on stable isotope analysis of human and animal bone samples. Our results show that this change affected females to a greater degree than males. We find that consumption of the newly introduced cereals was associated with less consumption of animal products and a higher rate of skeletal stress markers among females. We hypothesized that the observed separation of dietary signatures between males and females marks the rise of male-biased inequality in early China. We test this hypothesis by comparing Eastern Zhou human skeletal data with those from Neolithic Yangshao archaeological contexts. We find no evidence of male–female inequality in early farming communities. The presence of male-biased inequality in Eastern Zhou society is supported by increased body height difference between the sexes as well as the greater wealth of male burials.
Or, in the words of the Scientific American:
"The bone chemistry indicates that male and female diets were similar during the Neolithic period, which started about 10,000 years ago and in which agriculture began. Both sexes ate meat and grains. "During early farming, females contributed a lot to food production. [Men and women] ate the same things, and they're of more or less equal standing,"  says Kate Pechenkina, an archaeologist at Queens College, City University of New York, and senior author on the paper.

"The menu shift began at the end of the Neolithic and continued through the Bronze Age, often estimated to have begun in China around 1700 BC.  People there increasingly planted wheat, which leaves a carbon signature distinct from that of the millet they had already been growing.  The osteoanalysis shows that between 771 and 221 BC men continued eating millet and meat—but the latter disappeared from women's diets and was replaced with wheat.   Women's bones also began showing cribra orbitalia, a type of osteoporosis and an indicator of childhood malnutrition. "It means already from early childhood, young girls are treated poorly," Pechenkina says.
Very interesting work.  The one thing that bothers me is the compression of the time scale in the commentary.  1900 BC is the most late date for the introduction of wheat; 1700 BC is the date for the beginning of the Bronze Age in China; and the diet shift for women occurred almost a thousand years later.

Friday, April 14, 2017

Abrahamic-centrism

Yuval Noah Harari has an article at Bloomberg: Humankind: The Post-Truth Species.  He indulges in an Abrahamic-religion centrism when he writes:
"We are the only mammals that can cooperate with numerous strangers because only we can invent fictional stories, spread them around, and convince millions of others to believe in them. As long as everybody believes in the same fictions, we all obey the same laws, and can thereby cooperate effectively."
The wars in the great epics - the Ramayana, the Mahabharata, and I think in the Illiad, are all among people who "believe in the same fictions".

In The Heathen in His Blindness, Balu points out:

The Roman empire was made up of about 1200 city units, plus a considerable number of ethnic groupings which we label `tribes’ and/or ‘client kingdoms’.The divine forces worshipped in each of these units might be seen as similar, analogous, or parallel; one obvious example is the Juno, the cohesive force which gives life to any social unit, whether a family or a city-state. The Romans worshipped not only the Juno who had once belonged to their own kings – Juno Regina – but also the Junones of other states whom the Romans had invited to abandon their original communities and settle at Rome...These Junones were parallel, but not identical, in the same way as the many Jupiters and Zeuses worshipped throughout the empire were parallel but not identical. Each cult honoured its own god. (Wiedemann 1990: 69.)

( Menucius Felix, a Christian writer from around 210 C.E., has Caecilius – the pagan protagonist in The Octavius - )

[The Romans adore all divinities]...in the city of an enemy, when taken while still in the fury of victory, they venerate the conquered deities...in all directions they seek for the gods of the strangers, and make them their own...they build altars even to unknown deities...Thus, in that they acknowledge the sacred institutions of all nations, they have also deserved their dominion. (The Octavius, in Roberts and Donaldson, Eds., n.d.,Vol. IV: 177.)
Indian cultural unity and that thing called "Hinduism" arises similarly.

It is the Abrahamic religions that have made myths into truth-claims - supposedly objective statements about reality - and have slaughtered millions and destroyed entire cultures.  And Harari turns these Abrahamism into those of all of humanity. 


Data Recovery from Network Attached Storage

I found this page on data recovery from Network Attached Storage to be useful, but it wasn't at the top of my search results, so adding a link to it.

Saturday, April 08, 2017

Vegetarian Neanderthals and what that implies

Per NPR studies of the dental calculus (hardened plaque, tartar) from three Neanderthal specimens showed that the individual from a cave in Spy, Belgium was largely carnivorous; while two individuals from El Sidrón cave in Spain were vegetarian.

Laura Weyrich, the lead on this study is quoted as follows:
She says the difference in diets reflects the fact that the two groups lived in two very different environments.
Northern Europe, including Belgium, had wide open spaces with grasslands and many mammals. "It would have been very grassy, and kind of mountainous," says Weyrich. "You can imagine a big woolly rhino wandering through the grass there." Perhaps tracked by hungry Neanderthals looking for dinner.

But farther south in Spain, the Neanderthals lived in dense forests. "It's hard to imagine a big woolly rhino trying to wedge themselves between the trees," says Weyrich. And so, she says the Neanderthals there feasted on all kinds of plants and mushrooms. "They're very opportunistic, trying to find anything that's edible in their environment."
We are told by supposedly respectable historians that want to write a grand narrative for the human race that the human body has evolved handle a particular diet.  The very fact that humans adapted to environments from the frigid north where little green grows, to the equatorial regions, or at least environments as varied as ancient Belgian grasslands and dense Spanish forests indicates that humans were not evolved to handle any particular diet.   (Don't quibble that this study is about Neanderthals, not homo sapiens sapiens; our non-Neanderthal ancestors were more successful than the Neanderthal line, and so likely were even more adaptable than the Neanderthals.)

What is amazing is that people with a supposedly scientific temper swallow this historian nonsense with little to no skepticism.   Since I don't think we evolved to credulously believe historians, I'm not sure what is the basis for this lack of skepticism.