Monday, July 31, 2017

The Relationship Between The Bell Beaker Culture And Steppe Origins Is Still Opaque

We know from reliable ancient DNA that almost all of Europe (except Iberia) experienced an extreme shift in its population genetic makeup in a roughly one thousand year period after the first wave of farmers in Europe hit a serious slump, in the late Neolithic and early Bronze Age period. In some places, like the British Isles, the impact approximated total replacement.

This revived farming in Europe, coincided with a dramatic rise in lactase persistence, created a new predominant pigmentation phenotype in Europe, infused lots of steppe ancestry into the gene pool, brought a couple of major clades of Y-DNA R1 from very rare to predominant in Europe, and increased the frequency of some mtDNA H clades in Europe significantly. When it had run its course, modern Europe's gene pool was more or less in place. These events more or less coincide with the expansion of the Corded Ware culture in the East (associated with Y-DNA R1a) and with the expansion of the Bell Beaker culture in the West (associated with Y-DNA R1b).

This description doesn't do justice to how extreme what was going on must have been to produce the results that it did. One ethnic group waltzed in and took over and dominated an entire continent previously controlled by other ethnic groups, not just ruling them but at least partially replacing them. Maybe it was conquest. Maybe it was genocide. Maybe the existing people were experiencing an apocalyptic collapse and newcomers arrived and filled the vacuum. The story may have been different at different times and different places. But, it was an epic, vast and traumatic transformation.

Probably the only remotely similar transformation recent enough to have people who experienced who are still living it was the mass migration of Jews to Palestine in the 20th century, and the making of the modern Israeli state, although in the broader sweep of the human history and pre-history, there were many similar events (e.g. Cro-Magnon replacement of Neanderthals in Europe, the first wave Neolithic replacement of hunter-gatherers in Europe, Hebrew migrations into the Levant described in the Biblical Book of Numbers, Bantu expansion in Africa, Han Chinese expansion in Asia, European migration to the Americas and Australia respectively, South Arabian migration to northern Ethiopia, Inuit replacement of Paleo-Eskimos in the Arctic, Na-Dene migrations to the American Southwest).

We now have a lot more ancient DNA from the Bell Beaker culture. And, outside of Iberia, ancient DNA from Bell Beaker people suggests a population with almost as much steppe ancestry as the clearly Indo-European Corded Ware people who were their contemporaries in Eastern Europe.

But, in Iberia, which archaeological evidence points to as the place of origin of the Bell Beaker culture, there was a transition to the Western European clade of Y-DNA R1b (reaching a European peak in the Basque people of the same geographic vicinity), but the amount of steppe admixture is much lower, although not zero.

It isn't really obvious what kind of narrative explains this phenomena.

Were there two separate streams of steppe introgression/replacement with distinct origins? Perhaps an infiltration in Iberia, and an steppe invasion from Central Europe that experienced a culture (and perhaps language) shift to the Bell Beaker culture en route?

Was the Bell Beaker culture a predominantly indigenous invention, which people with steppe ancestry hijacked once it had gathered up steam.

Or, did the steppe ancestry people play an important part in giving rise to the Bell Beaker culture? Perhaps there was a founder population of steppe men in the original Bell Beaker formative community that provided strong cultural advantages to members of the culture, with a relatively modest demic impact. Perhaps those leaders were steppe people who only gained a demic advantage through founders effects when their children dominated the founding populations of Bell Beaker colonies (which native Iberians lacked an inclination to join). Then, did those Bell Beaker colonies perhaps transform non-Iberian societies more than they transformed Iberian ones where society was already relatively "advanced" (and hence less prone to falling sway to steppe cultural dominance)?

Are there other plausible narratives?

We still don't know why Western Europeans ended up with lots of Y-DNA R1b found further south on the steppe, while Eastern Europeans who derived from Corded Ware migrants ended up with lots of Y-DNA R1a. The Bell Beaker culture seems to be intimately tied to the rise of Y-DNA R1b in Western Europe, but we can't point to its origins on a map with any great specificity.

The ancient DNA evidence provides clues, but no really clear cut answers and ultimately, raises as more new questions than it does provide answers to old ones. And, of course, we are particularly looking through a glass darkly when we try to assign linguistic affiliations to already hard to fathom migration waves.

Did the Y-DNA R1a people of the steppe speak a different language (Indo-European or otherwise) from the Y-DNA R1b people of the steppe? They were certainly fairly well sorted patrilineages despite an absence of obvious physical boundaries between the two populations (although more ancient DNA suggests that the sorting was not complete).

Were the Bell Beaker people linguistically Indo-European, Vasconic, something else, or were they not linguistically homogeneous? 

If the Bell Beaker people, or some of them, were linguistically Vasconic, is that a language brought by steppe populations to Western Europe, or is it a language derived from the first farmers of the region (perhaps a language of Iberian farmers in particular, where the genetic impact on the Bell Beaker people was weakest, suggesting a potential that they rather than the locals could have experienced a language shift, and where the Vasconic languages were attested last historically).

If some or all of them were Indo-European linguistically, were the proto-Celtic or pre-Celtic, even though linguistic study of the Celtic and Italic languages suggests an early Iron Age time depth, rather than an early Bronze Age or Enolithic time depth? If so, what makes this language family look so young?

In the meantime, we are rapidly collecting more puzzle pieces in the hope of finding answers to these questions. 

A Record Month For Blogging

The only month in the history of this blog in which I have made more posts than I did this month was in December of 2016. If I stay at a modest pace of at least 15 posts a month for the last five months of the year, on average (who knows if I will), this will also be a record year for this blog.

Feel free to suggest any topics you would like to see covered in future posts at this blog in the comments. I don't promise that I will cover all or any of them, but I'm always open to good suggestions.

Many Celtic Place Names Don't Follow Gaelic Grammar

The Old European culture blog explores a curious aspects of many Irish and European toponyms in places in Europe that were historically Celtic at one point, as a side observation about Crom Cruah, a mountain which Irish pilgrims climb on the last Sunday of July (Reek Sunday):
Before you say that if Crom Cruach really meant Crom's Stack, Crom's Mountain, it would have had to be written Cruach Crom. This is because the Irish grammar says that when making compound words, you should always put adjectives after nouns. However there are lots of place names in Ireland that do not confirm to this rule. Place names such as Dubh Linn ("black pool" = Dublin) and Leixlip ("salmon leap") for instance. These place names were attributed to the Norse settlers who learned Irish had trouble with putting adjectives after nouns, so they often put them before the noun. This is exactly what happens when you force the new language on subjected population. They pick up the words but keep their own grammar. But this "incorrect" use of Irish grammar is present in all old Irish texts, which shows that it predates the Norse arrival to Ireland. For instance Táin Bó Cúailnge, is filled with epithets like finnbennach "white-horned", dóeltenga "beetle-tongued", echbél "horse-lipped", rúadruca "red-blushing", and the like.  
Funnily enough most toponymes and hydronymes of Celtic origin in central Europe follow this "incorrect grammar" and have adjective before the noun.

Here is an example: 
Gaelic word for “big” is Mór. (Pronounced as the English word more) 
Gaelic word for “river” is Abhainn . (Pronounced “awon” similar to the English word award). Proto celtic word is awa.

In central Europe there are numerous rivers called Morava. 
Morava = mor + ava = Mór Abhainn = Mor Awa= big river

Morava is the biggest river in Serbia and also in Czech republic, territories which were considered Celtic heartland. These rivers gave the name to the territory upper and lower Moravia.

In Ireland there is a river named the Avonmore River (Irish: Abhainn Mhor, meaning "big river") which is the same as Mor Ava just using Gaelic grammar.
There are at least two ways that this could be explained. 

One is that proto-Celtic didn't follow Gaelic grammar, because Gaelic acquired its grammar as a substrate influence on proto-Celtic from whichever (probably non-Indo-European) language was spoken before Gaelic in Ireland (possibly the language of the first farmers, possibly a Vasconic language spoken by the Bell Beaker people).

An alternative possibility is that Gaelic grammar, on a frontier where there was near total replacement and there was modest subsequent influence from neighboring languages, is the grammar of proto-Celtic and that the non-Gaelic grammar is the substrate that was replaced by Celtic languages.

Is Loop Quantum Gravity Equivalent To String Theory?

Three papers discussed in a recent thread at the Physics Forum discuss this possibility that String Theory and Loop Quantum Gravity, the two main approaches to quantum gravity theory, are equivalent. The papers are (emphasis and paragraph breaks in the abstracts are mine):
A new duality between Topological M-theory and Loop Quantum Gravity Andrea Addazi, Antonino Marciano (Submitted on 17 Jul 2017) 
Inspired by the long wave-length limit of topological M-theory, which re-constructs the theory of 3+1D gravity in the self-dual variables' formulation, we conjecture the existence of a duality between Hilbert spaces, the H-duality, to unify topological M-theory and loop quantum gravity (LQG). By H-duality non-trivial gravitational holonomies of the kinematical Hilbert space of LQG correspond to space-like M-branes. The spinfoam approach captures the non-perturbative dynamics of space-like M-branes, and can be claimed to be dual to the S-branes foam. The Hamiltonian constraint dealt with in LQG is reinterpreted as a quantum superposition of SM-brane nucleations and decays.

Cite as: arXiv:1707.05347 [hep-th] 
New Variables for Classical and Quantum Gravity in all Dimensions I. Hamiltonian Analysis Norbert Bodendorfer, Thomas Thiemann, Andreas Thurn (Submitted on 18 May 2011 (v1), last revised 12 Feb 2013 (this version, v2)) 
Loop Quantum Gravity heavily relies on a connection formulation of General Relativity such that 1. the connection Poisson commutes with itself and 2. the corresponding gauge group is compact. This can be achieved starting from the Palatini or Holst action when imposing the time gauge. Unfortunately, this method is restricted to D+1 = 4 spacetime dimensions. However, interesting String theories and Supergravity theories require higher dimensions and it would therefore be desirable to have higher dimensional Supergravity loop quantisations at one's disposal in order to compare these approaches. 
In this series of papers, we take first steps towards this goal. The present first paper develops a classical canonical platform for a higher dimensional connection formulation of the purely gravitational sector. The new ingredient is a different extension of the ADM phase space than the one used in LQG, which does not require the time gauge and which generalises to any dimension D > 1. The result is a Yang-Mills theory phase space subject to Gauss, spatial diffeomorphism and Hamiltonian constraint as well as one additional constraint, called the simplicity constraint. The structure group can be chosen to be SO(1,D) or SO(D+1) and the latter choice is preferred for purposes of quantisation. 
Journal reference: Class. Quantum Grav. 30 (2013) 045001
Cite as: arXiv:1105.3703 [gr-qc]

Towards Loop Quantum Supergravity (LQSG) Norbert Bodendorfer, Thomas Thiemann, Andreas Thurn (Submitted on 6 Jun 2011 (v1), last revised 12 Jun 2012 (this version, v2)) 
Should nature be supersymmetric, then it will be described by Quantum Supergravity at least in some energy regimes. 
The currently most advanced description of Quantum Supergravity and beyond is Superstring Theory/M-Theory in 10/11 dimensions. String Theory is a top-to-bottom approach to Quantum Supergravity in that it postulates a new object, the string, from which classical Supergravity emerges as a low energy limit. On the other hand, one may try more traditional bottom-to-top routes and apply the techniques of Quantum Field Theory. 
Loop Quantum Gravity (LQG) is a manifestly background independent and non-perturbative approach to the quantisation of classical General Relativity, however, so far mostly without supersymmetry. 
The main obstacle to the extension of the techniques of LQG to the quantisation of higher dimensional Supergravity is that LQG rests on a specific connection formulation of General Relativity which exists only in D+1 = 4 dimensions. In this Letter we introduce a new connection formulation of General Relativity which exists in all space-time dimensions. We show that all LQG techniques developed in D+1 = 4 can be transferred to the new variables in all dimensions and describe how they can be generalised to the new types of fields that appear in Supergravity theories as compared to standard matter, specifically Rarita-Schwinger and p-form gauge fields.

Journal reference: Phys. Lett. B 711: 205-211 (2012)
Cite as: arXiv:1106.1103 [gr-qc]
Of course, it makes sense that any two quantum gravity theories that by design are supposed to approximate General Relativity in the classical limit, should have similarities to each other.

More On The Jewish Genetic Heritage

Since we have two other posts today on Rabbinic Jewish history, why not a third?

This is an excerpt from a post by Razib Khan on the topic (emphasis in the original):
Can 23andMe Tell Us If Jews Are A Race — And Is That A Good Thing? The author interviews scientists who know the science, but he still manages to garble and confuse everything. First, Ashkenazi Jews descend from a endogamous community which flourished in Central Europe probably no earlier than ~1000 AD. That is why a Ashkenazi Jewish cluster emerges naturally out of the population genetic data; there’s a real coherent demographic history being reflected. Whether that’s a “race” or not I’ll leave to the reader. 
Second, the story states that “Sephardic Jews are not considered a distinct population by either company, or by researchers — their genetic make-up is not sufficiently different from surrounding North African, Iberian and Greek populations.” This very misleading. To a great extent Sephardic Jews are rather distinct from the surrounding populations. There is some evidence of shared ancestry in Moroccan Jews with Moroccan Berbers (I know because I’ve looked at a lot of this data), but it’s a small proportion. Similar things can be said about most Sephardic communities. But, they are not nearly as coherent a genetic cluster as Ashkenazi Jews. There has been some gene flow and assimilation with many local Jewish populations (e.g., the Syrian Sephardic Jews absorbed a local Levantine Jewish community, which had its own liturgy until the 19th century).
For what it is worth,  the source article is pretty much useless unless you are more interested in why people care about their personal genetic ancestry and how they feel about it, then about the population genetic history of the Jewish community.

Was There A Babylonian Renaissance?

In his "History of the Yiddish Language" Max Weinreich regarded the 13th century as a turning point in the history of the Yiddish language. He identifies it as the boundary between the Early Yiddish and Old Yiddish periods. More specifically he writes about a 13th century Babylonian Renaissance characterized by a change in the Ashkenazic norms of Hebrew pronunciation. He says that the change was centered around Rothenburg and involved scholars who bore names that were previously rare or unknown among German Jews but were used by Jews in the Middle East. The name Bablyonian Renaissance comes from Weinreich's beliefs that the pronunciation norms came from Mesopotamia and that the scholars who brought them migrated from there.
From Charles Nydorf at Gothic Yiddish.

The post by Mr. Nydorf continues by marshaling evidence that studies of Ashkenazi Jewish genetics corroborate this date as an important one for a major German-Middle Eastern admixture and for a bottleneck followed by a population expansion mostly derived from this core group.

Climate Change Drives Violence Against Scapegoats

A new study by Robert Warren Anderson, Noel Johnson and Mark Koyama suggests that, historically, economic shocks were more strongly associated with outbreaks of violence directed against Jews than scholars had previously thought. The authors collected data for 1,366 anti-Semitic events involving forced emigration or murderous pogroms in 936 European cities between 1100 and 1800. This was then compared with historical temperature data from a variety of sources, including tree rings, Arctic ice cores and contemporary descriptions of the weather. 
Cold spells hit medieval agriculture hard: a one-degree Celsius fall in temperatures reduced the growing season by up to four weeks. Lower yields caused widespread economic pain: up to 57% of people relied on farming for work in medieval England, for instance. The authors find that a fall in average temperatures of only a third of a degree increased the probability of a pogrom or expulsion by 50% over the next five years. They argue that violence against Jews was not simply caused by religiously-motivated anti-Semitism: “The Jews were convenient scapegoats for social and economic ills.” 
The authors find that economic shocks had greater effects where soils were less suited to farming or where governments were weaker, and so less able to stop violence.
Via Marginal Revolution citing the Economist.  The closed access paper is here.

While the data above is specific to anti-semitic pogroms in Europe, there are fairly strong indications in the archaeological record (for example, from Southern Colorado during prehistoric droughts there), that this is a universal and global phenomena.

Friday, July 28, 2017

General Properties Of Quantum Gravity

There are important ways in which all quantum gravity theories must differ from general relativity:

1. Gravitational energy is localized.

2. Local conservation of energy by gravitons means that any non-conservation of energy by gravity arises from a source other than gravitons.

3. Newton's constant or a related dimensionless coupling constant of gravity runs with energy scale.

4. There should be graviton loops in all quantum field theories and this should impact the renormalization and running of other Standard Model constants with energy scale.

5. Gravitons couple to everything in proportion to its mass-energy, so in principle it ought to be possible for some combinations of particles to annihilate to gravitons and for high energy gravitons to decay to hypothetically just about any possible particle.

6. As a self-interacting massless boson, gravitons will share many properties of gluons qualitatively.

Establishing Prehistoric Networks With Metallurgy

In theory, copper is a pure element that is identical everywhere. But, in the real world, copper mined in particular places and processed with copper and Bronze Age technology has a distinctive chemical signature based upon its place of origin.

A new study exploits that fact to empirically determine the trade and archaeological culture networks of the prehistoric Balkan Peninsula and that vicinity.

Tuesday, July 25, 2017

Reaching Conclusions From Dry Eraser Waste From A 1000 Year Old English Bible

One of the ways that you prevent old books from decaying is to clean their parchment pages with a dry eraser. The waste removed in this process contains micro-fragments of the parchment material (which contains DNA from the cattle whose skins went into make it), DNA from people who have touched it, and the DNA of microorganisms that have collected on its surface.

This information, combined with other information about the object, can provide an additional window into the past.

Researchers recently did this analysis with the York Bible, which was written several decades before the Norman Conquest of England in 1066 CE, was probably written in 990 CE, and continues to be used by the Anglican Church (now, mostly as a devotional object rather than as a practical text).

The most interesting conclusion that they reached is that the York Bible's parchment came mostly from female calves, even though usually male calves are used to make parchment because male calfs aren't important for producing milk or expanding the herd. This was probably due to the fact that there was a major die off of cattle in England a couple of years before the book was written, due to a cattle disease, which left an excess of calf hide from both genders which could be used to make parchment.

Cosmological Constant Numerology

While this particular hypothesis is probably wrong, I have a soft spot in my heart for "numerology" attempting to get to the bottom of why fundamental physical constants have the values that they do, in part because these explorations deepen one's understanding of these constants even if they don't bear out. 
In the early-mid 20th century Dirac and Zel'dovich were among the first scientists to suggest an intimate connection between cosmology and atomic physics. Though a revolutionary proposal for its time, Dirac's Large Number Hypothesis (1937) adopted a standard assumption of the day, namely, the non-existence of the cosmological constant term (Λ=0). As a result, its implementation necessitated extreme violence to the theory of general relativity -- something few physicists were prepared to sacrifice in favour of `numerology' -- requiring a time-dependent gravitational coupling of the form G(t)1/t. Zel'dovich's insight (1968) was to realise that a small but nonzero cosmological term (Λ>0) allowed the present day radius of the Universe to be identified with the de Sitter radius, rUldS1/Λ, which removed the need for time-dependence in the fundamental couplings. Thus, he obtained the formula Λm6G2/4, where m is a mass scale characterising the relative strengths of the gravitational and electromagnetic interactions, which he identified with the proton mass mp. In this paper, we review a number of recent arguments which, instead, suggest the identification m=me/αe, where me is the electron mass and αe=e2/c1/137 is the usual fine structure constant. We note that these are of a physical nature and, therefore, represent an attempt to lift previous arguments a la Dirac from the realm of numerology into the realm of empirical science. If valid, such arguments suggest an intimate connection, not only between the macroscopic and microscopic worlds, but, perhaps even more surprisingly, between the very essence of "dark" and "light" physics.
Matthew J. Lake, "Is there a connection between "dark" and "light" physics?" (July 21, 2017).

The body of the paper notes that four independent researchers have come up with this formula since 1968 by different, although not inconsistent methods.

The cosmological constant appears in Einstein's field equation in the form:

and the value of Λ, the cosmological constant of General Relativity, is known so imprecisely that pretty much any formulation the produces a result with the right order of magnitude can be consistent with observation. 

The least precisely known physically observed constant that is important to know in order to estimate the value of the cosmological constant is Hubble's constant, for which, according to the Particle Data Group, the leading direct measurement has a 5% margin of error, the leading indirect measurement has a 1.5% margin of error (the two leading measurements are in tension with each other, although not beyond the two sigma threshold usually set as the standard for inconsistent measurements):
The most recent derivation based on this approach utilizes the maser-based distance to NGC4258 to re-calibrate its Cepheid distance scale to obtain H0 = 72.0 ± 3.0 kms−1 Mpc−1. The major sources of uncertainty in this result are due to the heavy element abundance of the Cepheids and the distance to the fiducial nearby galaxy, the Large Magellanic Cloud, relative to which all Cepheid distances are measured. 
The indirect determination of H0 by the Planck Collaboration found a lower value, H0 = 67.8 ± 0.9 kms−1 Mpc−1. As discussed in that paper, there is strong degeneracy of H0 with other parameters, e.g., Ωm and the neutrino mass. The tension between the H0 from Planck and the traditional cosmic distance-ladder methods is under investigation.
The best fit value for the cosmological constant based upon currently available data according to the paper is:

Λ = 1.114 ×10−56 cm−2 (which is stated to spurious accuracy by one or two orders of magnitude). 

Wikipedia quotes a value of it has the value (converting units from meters to cm) of:

Λ = 1.19×10−56 cm−2 

The proposed formula yields a cosmological constant value of:

Λ = 1.366×10−56 cm−2 (which is stated in a manner consistent with the precision of the least accurately measured constant that goes into it "G"). 

The value produced by the proposed formula, of course, is 14.7% higher than the experimentally measured value and is clearly inconsistent with it given the margins of error with the measured value. 

There has been a controversial suggestion that one of the important measurements that goes into determining the cosmological constant directly is wrong because it conflates two different kinds of Type 1a Supernova, which are hard to distinguish from each other at optical wavelengths, but are quite distinct at other wave lengths. But, if that is the case, the cosmological constant would actually be smaller than the best fit measured value shown above, not somewhat larger like this theoretically determined value. That paper is J.T. Nielsen, A. Guffanti an S. Sarkar, "Marginal evidence for cosmic acceleration from Type Ia supernovae" 6 Scientific Reports 35596 (October 21, 2016) (open access).