size does matter?

this was too important to hold off posting until my vacation is over:

from: Male Organ and Economic Growth: Does Size Matter?

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la endogamia en la españa medieval

ok. so, moving counter-clockwise around the periphery of europe: spain.

medieval spain is complicated. ¡muy, muy complicado! there are so many different populations: visigoths, other germanics, moors, basques, cantabri, jews…. so, this is not going to be the last word on inbreeding in medieval spain at all. it’s barely even the first word.

but, broadly speaking — really broadly speaking — there was a north/more outbred versus a south/more inbred divide in medieval spain. that’s pretty much because you had christians in the north who, like we’ve seen, were under pressure from the church authorities to out-marry; and you had muslims in the south who brought with them their tradition of strong inbreeding.

the visigoths controlled a large part of the iberian peninsula in the early medieval period (418-721). they converted (or, at least, their king at the time did) to nicene christianity in the late 500s (they’d been arian christians before that). ausenda suggests that the pre-christian visigoths married close-relatives, including cousins, and that they had a patrilineal, tribal society. like the other gemanic tribes, they began to outbreed more and more after converting to christianity since the church demanded out-marrying.

this scenario is probably more or less correct, but i wonder if the visigoths were actually less influenced by the church’s laws than other germanic peoples living further north, like the franks. mitterauer insists, rightly so imho, that tribalism and feudalism do not go together (see, for example, the irish). you cannot get to a feudal society until you get rid of tribalism — and you cannot do that without outbreeding. the visigoths in spain, according to mitterauer, were less feudalistic than their counterparts the franks, so perhaps they hadn’t moved so far along the outbreeding path as the franks during the early medieval period.

then the moors arrived and wreaked bloody havoc on the whole system.

from “Islamic and Christian Spain in the early Middle Ages” by thomas glick [pg. 146]:

“Until recently, the nature of kinship and its shaping effect upon social and political institutions in medieval Spain was not a topic accorded much importance by historians…. This imbalance has been rectified by the work of Pierre Guichard, who has demonstrated the tribal organization of Andalusi society of the Emirate and, in the Christian orbit, Ruiz-Domenec, Garcia de Cortazar, and others have identified the dissolution of the extended family as a significant and central social process of the high middle ages.

the latter pattern we’ve seen already amongst the northern germanics: the church and tptb put an end (more or less) to inbreeding in those populations which brought about the demise of the tribes. the introduction of the feudal/manorial system plus continued outbreeding further broke down the extended family (a tribe being just a very extended family) leaving central europeans with nuclear or stem families (a stem family is where one married child remains living with his parents, so you get grandparents + a nuclear family in one household).

more from glick [pgs. 146-48]:

“The Arabs and Berbers who conquered the peninsula did so not as isolated warriors, but as members of organized tribal groups. The Arabs and most of their early Berber allies were members of agnatic, patrilineal groups forming a segmentary social system, whereby individuals belonged to a hierarchy of increasingly inclusive segments, from the clan up to the tribal confederation. The basic tribal unit, the qawm (variously translated fraction or clan), is a unit of several hundred tents or families, linked agnatically. That is, the kinship system ascribes importance only to relationship through males. In such a system, endogamous marriages are viewed as the ideal because through endogamy power, prestige, and wealth are retained within the agnatic group rather than shared with a competing group into which a daughter might marry, with parallel-cousin marriages (the wedding of one’s son with the daughter of the paternal uncle [i.e. fbd marriage]) preferred. A cross-cousin marriage (with the daughter of the maternal uncle or paternal aunt) is considered exogamous because the offspring gain a different lineage. The more powerful a tribal group is, the more women it will attract from outside, the fewer it will lose, and the more endogamous it will become.

“Guichard demonstrates that the early Muslim residents of the peninsula settled in tribal or sub-tribal groups and that, indeed, it was the policy of important figures to travel with tribal entourages and to reconstitute their clans once the decision to settle in al-Andalus had been reached….

“Segmentary organization gives rise to typical political forms. The basic unit is the clan — the Arab qawm, the Berber canton — which lives and fights together. The segmentary tribal structure makes it possible for such groups to subsist in relative isolation and, at the same time, because they are embedded in larger solidarities, to join in political or military federations with related groups. This gives rise to the kaleidoscopic pattern of atomization and amalgamation which is so characteristic of western Islamic, particularly Berber, society.”

so, in moorish spain, we have arabs and berbers practicing fbd marriage and living in a tribalistic society. tens of thousands of people who had been living in spain before the arrival of the moors converted to islam during the medieval period. it’s unclear to me what percentage of them adopted the marriage practices of the conquerers. it sounds, however, as though it was not an insignificant amount as glick points out [pg. 151]:

[C]onsanguinity remained a powerful social force [throughout the middle ages] (and so remained even among the Moriscos of the sixteenth century, who resisted taking Spanish names because such an act made it impossible to keep track of agnatic lineages), as did ethnicity.”

finally, from glick again [pgs. 149-51]:

“Arab and Berber tribal structure found political expression in the organization of confederations or alliances, which were formed according to the underlying logic of segmentary societies. The essence of this kind of political organization is that politics is viewed as a zero-sum game. The wealth, power, and prestige of one’s own group are increased only by decreasing those of a rival group, leading to a more or less permanent state of conflict between neighboring groups as well as to characteristic patterns of alliances….

“Much of the political history of al-Andalus, therefore, is occupied with accounts of tribal in-fighting, generally along lines of moiety division….”

this is totally unlike what was happening in northern europe throughout the middle ages. northern europeans became less tribal — in spain, especially southern parts of spain, tribal life was alive and well.

until the reconquista.

glick describes how, in the wake of the reconquista, feudal structures took hold throughout spain, starting in the north and progressively moving southwards. the population converted back to (or to) catholicism — ’cause they had to — and, presumably, they had to start following the catholic codes on marriage, altho as we saw above the mariscos resisted this for quite a long time.

quite extraordinarily, researchers looking at catholic church dispensations for cousin marriage in sigüenza in north-central spain between the 1950s and 1980s found that the folks there were marrying their first- and second-cousins at a rate of 12.6% [pg. 4; abstract here]. in the early 1940s, the overall rate for endogamous marriage in spain — and this is including uncle-niece marriage — was 4.1% [pg. 4]. the overall rate for france in the late 1940s was 0.8%; london in 1950, 0.4%; the netherlands in the late 1940s, 0.2% [pgs. 2 & 5]. close relative marriage has obviously remained more common and more important for longer in spain than in northern european populations.

so, now we’ve looked at one of the i’s and the s. the p is prolly pretty similar to spain. next stop, italy. aaaaaah — la dolce vita! (^_^)

edit: boilerplate and boilerplate 2.0

previously: inbreeding in europe’s periphery

also previously: northern vs. southern spanish iq, redux and, from the reluctant apostate, Mapping The 2009 PISA Results For Spain And Italy

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inbreeding in europe’s periphery

so, we’ve seen that, starting in the early medieval period, the church and tptb put the brakes on inbreeding in europe. by the eleventh century, you weren’t allowed to marry even your sixth cousin (although this was knocked back to fourth cousin in the following century). most of this happened in the heart of europe, starting in frankish territory and spreading outwards through what is today france, germany, england, northern italy and northern spain, plus at least parts of scandinavia.

but what about the more peripheral regions of europe? what happened in places like the iberian peninsula and sicily and the balkans? russia and slavic countries east of the hajnal line? ireland and scotland? things didn’t play out in those regions like in the core of europe. let’s start with what happened in … (*hbd chick throws dart at map*) … ireland.

in pre-christian ireland [pg. 289]:

“Although … as in the rest of early Europe, there were no hard and fast rules governing the choice of marriage partner (other than a taboo on primary incest), there was a preference for marriage between close kin (in-marriage), and for matches between children of fathers of equal rank (isogamy).”

not a big surprise there. the christian church, as per usual, tried to put a stop to in-marriage in ireland like they did elsewhere, but without much success [pg. 291]:

“Connected to the practice of dowering women was the preference for marriage with close kin; this tended to conserve property within the fine [paternal kin], or between pairs of fine branches that repeatedly intermarried. Clerical complaints offer indirect testimony to the Irish preference for canonically ‘incestuous’ marriage. The seventh-century source, the ‘Second Synod of St. Patrick’, records that the Romani — a faction of the Irish clergy advocating greater conformity to Roman Catholic practices — attempted to insist upon ‘what is observed among us, that they be separated by four degrees’, i.e. that men should not marry their first cousins (the fourth degree kinswoman). The nativists protested that they had ‘never seen nor read’ such a rule.

Again, in the eleventh century, churchmen singled out tolerance of ‘incest’ (marriage of kin) as a major fault of the Irish church. Such laxity was a scandal to Canterbury in the later middle ages, not only in cases involving famous families, but apparently amongst the general population. So weak were the sanctions against in-marriage, that incidents are recorded in which men were sexually involved with aunts and nieces — not in covert relationships, but marriages for which the parties tried to gain sanction and blessing. Even in the law tracts there survives a hint that Roman Catholic complaints were not without foundation, for Corus Bescna [one of the brehon law tracts] asks:

“‘What is the corus fheini? (laws of the farmers) Joint-plowing, marriage, giving in charge, lending … (Commentary) marriage — the daughter of each to the other, i.e., to such as one as is not cursed by the patron saint of the land.’

“A curse from the local saint could be incurred on a large number of grounds, such as associating with the various categories of society tainted with paganism, not paying one’s tithes, or simply belonging to a hostile group. The point is that a neighbor, even a close kinsman, was preferred as a husband because his exact social position was well-known — a sentiment shared by the Welsh and expressed in the proverb, ‘marry in the kin and fight the feud afar.‘”

so, even by the eleventh century, close-relative marriage was still the way to go in ireland — and not just cousin marriage, but even closer (genetically speaking) uncle-niece and aunt-nephew marriages. that’s very different from what was happening on the continent at the same time.

the normans tried to put a stop to the inbreeding practices in ireland; but they actually went native after a century or two and adopted a lot of the local irish laws and practices, so i’m not sure how successful they were at eliminating close-relative marriage in ireland. i don’t think they can have had much luck (o’ the irish), because as goody points out [pg. 16]:

“In the period of the classical civilisations, forms of clan organisation apper to have existed right round the Mediterranean, as it still does among the pastoral peoples of North Africa and some hill tribes of the Balkans, and in very residual forms in Ireland and Scotland.”

very residual forms of clans still exist in ireland (and scotland) because in-marriage practices must’ve existed until quite recently.

mitterauer discusses at some length how the medieval irish also did not adopt the new agrarian practices that peoples on mainland europe did, but rather stuck mostly to cattle herding [pg. 10]:

“There were also strong contrasts in the extreme northwest of the continent, in the British Isles. Whereas in England, parallels with agrarian developments in France could be found early on, particularly in its fertile southeast, the situations in Ireland and Scotland were vastly different. In England, wheat and barley had predominated in Roman times, but rye and oats had also been introduced, possibly to supply the army. These two grains subsequently brought about the expansion of agriculture onto poorer soils, thus making an important contribution to the process of cerealization. In Ireland there was no such development, even in the High Middle Ages; an animal-based economy was clearly predominant. This is reflected in the variations in social prestige among different population groups depending on whether they raised animals or farmed. Oats took pride of place in grain growing, followed by barley, wheat, and rye, with rye, the new grain for making bread, coming last.”

in addition, since the irish remained tribal or clannish (as a result of the inbreeding practices), the manorial system of mainland europe did not take hold, either.

inbreeding = tribalism/clannishness ≠ corporate structures in society [pgs. 42-3]:

“The situation in early medieval Ireland can shed light on the inter-connections between the predominance of cattle breeding and lordship over the land and its people. Structures analogous to the Frankish manorial system did not emerge there, but manorial forms certainly did. Irish lords distributed arable land to unfree, homeless people, the so-called fuidri….

“These patron-client relations did not generate a familia as they did on Frankish estates; social structuring was still maintained through kinship. It seems that mills and kilns were typically owned by kinship groups in common, and it was only at monasteries that these buildings were the key facilities on a manorial estate. Given that a livestock economy was dominant, these facilities were much less significant in Ireland than even the rather anemic Irish crop production. In this respect, too, there were no institutions that would enable the bipartite estate to gain a toehold. Because of these agrarian contexts and the aligning of its social structures with kinship, the organization of power developed very differently in early medieval Ireland that in the Frankish Empire. ‘Cattle lords’ and lower-level kings dominated the scene.

for “lower-level kings” read: the heads of clans or tribes.

when a society’s marriage practices are based on inbreeding, you get a nepotistic society (think daley-dynasty machine-style politics or tammany hall) because, due to inclusive fitness related drives, people favor their own more than strangers. in medieval irish society, they didn’t even manage to adopt feudalism because who on earth would swear fealty to some lord that you weren’t related to?! the whole concept prolly just didn’t make any sense to the medieval irish — because the church hadn’t managed to persuade the population to quit inbreeding.

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inclusive fitness stuff

i think inclusive fitness is one of the coolest concepts. ever. it doesn’t explain everything in Life, of course, but it explains a lot. it’s certainly helped me to make sense of why people (most organisms) behave in the ways that they do towards other individuals.

here are some neat examples of inclusive fitness affecting human behavior from robin (ian macdonald) dunbar [pgs. 137-39]:

[T]here is plenty of empirical evidence to suggest that, irrespective of the importance of social kinship, biological (i.e. genetic) kinship does play an important background role in the decisions that individuals make on how they should treat each other. In an analysis of Icelandic Viking sagas, for example, my colleagues and I showed that individuals were significantly less likely to murder close relatives (those related to ego as paternal cousins or better) than less closely related individuals (for a similar analysis of the English kings and queens, see Johnson and Johnson 1991). More importantly, their willingness to murder relatives was modified by the value of the action to the murderer: they were willing to murder distant relatives for trivial benefits (e.g. in a drunken brawl), but close relatives were only murdered if the gains were very high (e.g. by doing so, they inherited an earldom or land). Similarly, the Vikings were more willing to form alliances (or to make loans of ships, supplies, or men for expeditions) with close relatives than more distant ones, and when they did so were less likely either to demand explicit reciprocation or to renege on the agreement later.

“Note that it does not matter much how the Vikings themselves construed their patterns of kinship in these cases: these findings are based entirely on pedigrees constructed out of declared paternities. While the Vikings may have occasionally made mistakes about paternity, as we all do, paternity (and maternity) were important to them because they were associated with rights to land. These paternities are, of course, all taken from the Vikings’ written records, the sagas that were composed and/or written down mainly in the thirteenth century to provide records of individual family histories. As with all historical records, we might ask whether we can rely on them: after all, victors in history tend to colour the accounts they give with their particular view. There are, however, three relevant circumstances in this particular case. First, these accounts were written for public consumption by a very small community (medieval Iceland) where most people were intimately familiar with both the events and the characters described (in most cases, their own immediate ancestors): they would not have hesitated to say so if Snorri Sturlson (who was responsible for composing a great many of the Icelandic sagas in the 1220s and 1230s) had made too many egregious errors. Second, the Vikings themselves were very clear on real paternity (as best as they could define it biologically): despite the fact that fostering was a major feature of their world (as it continued to be into quite recent times throughout northern Europe), they made a clear distinction between foster-sons or foster-brothers and real sons or real brothers. Foster-sons could inherit land from a foster-parent if the parent so chose, but they did so by right of adoption and not by birth-right. Finally, even if the stories are complete fiction, we can still ask: did the Vikings compose their stories in such a way that they followed biological prescriptions…?

“Another example of the way biological kinship intrudes into everyday life is provided by Madsen et al. They asked individuals from two different cultures (the UK and South African Zulus) to undertake a painful isometric skiing exercise for the benefit of relatives (who received a monetary or food reward that was directly proportional to the length of time for which the exercise was maintained). In five replicates of the experiment, the duration (and hence reward value) declined with declining relatedness to the subject. In this study, considerable care was taken in drawing up lists of potential beneficiaries to ensure that they were biological relatives of the specified degree. While there was inevitably a great deal of variation across individuals, the bottom line is that, on average, closer relatives did better than more distant relatives (or even children’s charities) across four degrees of relatedness (self vs siblings/parents vs grandparents/uncles/aunts/nieces/nephews vs cousins). When real sacrifice is involved (the exercise becomes excruciatingly painful the longer one does it), altruism is titrated by genetic relatedness.”

what i find really interesting (obviously, if you’ve been reading this blog for any length of time!) is how inbreeding (and outbreeding) relates to inclusive fitness. sure, a brother might be really predisposed to help out his brother much more so than a distant cousin — but what if that brother is also a cousin? shouldn’t cousin-brothers, on average, be willing to help each other more than just regular brothers? the answer seems to be yes.

what should be kept in mind about inclusive fitness, though, is that there are other social behaviors that it probably affects in addition to altruistic ones. ever since bill hamilton published his ideas on inclusive fitness, most researchers have been focused on altruistic behaviors. but one of hamilton’s papers was entitled “The Innate Social Aptitudes of Man.” note, not the innate altruistic aptitudes of man — but the social aptitudes of man. hamilton obviously thought his idea applied to other behaviors as well in addition to altruism.

one of those other behaviors, i think, is a drive to exercise some control over who your relatives (i.e. other individuals who share YOUR genes) mate with. i haven’t seen much discussion of this amongst sociobiologists — i referred to one interesting study in my “nepotistic nosiness” post. there’s more of this going on, i’m sure — or i bet, anyway. people (and other organisms) want to control, to different extents, how their relatives pass on the genes which they share in common. and, like in the proven cases of altruistic behaviors, they probably want to exercise greater control over the reproductive practices over closer relatives. AND, where inbreeding occurs, there are probably even stronger drives to control the reproductive practices of relatives, e.g. all the reproductive controls in saudi arabia where the cousin marriage rates are currently 50%+.

just some thoughts.

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fbd marriage in germanic tribes?

eh — i don’t think so.

giorgio ausenda in “Kinship and marriage among the Visigoths” and “The segmentary lineage in contemporary anthropology and among the Langobards” thinks yes, although he admits that there’s not much evidence either way. i already posted about the first article here; now here’s my summary of the second one:

ausenda examines the types of marriage, lineage and kinship systems in pastoralist societies that have been studied in modern times in order to infer what these structures may have been like in germanic tribes, since the germanics were also pastoralists. he discusses the father’s brother’s daughter (fbd) marriage system that’s found in the arab world, but he also points out that some pastoralists practice mother’s brother’s daughter (mbd) marriage [pg. 23-4]:

“Endogamous pastoralist populations are those belonging to the ‘Arab sphere’. These populations are considered endogamous because of their preference for patrilateral first cousin marriage, i.e. FBD marriage which, in fact, occurs with a very high frequency.

“Anthropologists explain such alliances in terms of the necessity of maintaining a close cooperation between an individual and his father and brothers for the benefit of the joint property, their livestock, and to further lineage stability.

“Many authors stress the considerable importance that sons have for the furtherance of the household’s pastoral economy. The endogamous practice stems from the fact that ‘the lineage group aims, primarily, at keeping a young woman to betroth her to one of its own young men’. The priority of a close kinsman’s claim to a girl is so stringent that among most populations marriage requests must be approved by close kin to make sure that no closer relative with a claim to the girl may come forward later….

Outside and bordering with the above areas some populations are exogamous, e.g. Central Asian nomads, the Toubou of Chad, Somali nomadic populations. While the features of Middle Eastern and North African endogamy have been carefully studied, the exogamy of other populations has not received a satisfactory explanation. In these cases the prevelant type of marriage is with MBD, i.e. with women belonging to the Mother’s clan, different from the agnatic one. Spencer pointed to this lack of explanation and ventured that the search for a mate outside one’s own group may be due not only to demographic reasons, i.e. lace of a suitable bride in one’s own clan, but also:

“‘…for more positive considerations, such as the need to maintain reliable relationships with other groups in ecologically strategic places, both nomadic and settled.'”

again, ausenda concludes that the pre-christian germanic tribes practiced fbd marriage, but i can’t see that he offered any good reason for his conclusion.

there are a few points that weigh in favor of mbd marriage, in my opinion:

1) that, according to tacitus, there was a strong, almost sacred, bond in early germanic society “between a mother’s son and a mother’s brother” [pg. 10]. mother’s brother? mother’s brother’s daughter marriage? it doesn’t seem like such a stretch to imagine that mbd marriage was pretty common when there was such a strong relationship between a man and his maternal uncle.

2) tacitus also noted [pg. 10]: “‘The larger a man’s kin and the greater number of his relations by marriage, the stronger is his influence when he is old.'” well that sounds like what spencer, quoted by ausenda above, said about mbd marriage and building alliances with outside clans. i talked about this in another post, too — marriages with maternal cousins offer greater alliance building opportunities than marriage with paternal cousins. paternal cousin marriages (fbd and fzd) keep everything and everybody in the same patrilineage. if you want lots o’ alliances and lots o’ extended family members, maternal cousin marriage is the way to go.

the next two points have to do with the status of women in fbd versus other societies. in fbd marriage societies, women have quite a low status — not just your usual secondary status to men (like in most traditional societies) — but really kinda freakishly low. think burqas and honor killings and not being allowed to drive in saudi arabia (altho maybe that’s a good thing!). so:

3) from wiki-p: “The weregild or recompense due for the killing or injuring of a woman is notably set at twice that of a man of the same rank in Alemannic law.” this is exactly the opposite of fbd marriage societies today — in saudia arabia and iran, for instance, the diyya (weregild) for a muslim woman is half that of a muslim man.

4) in all (i think) contemporary fbd socieites, women are required to follow purdah to some extent or another. head covering for women in northern europe, on the other hand, seems to have been introduced by the church. it does not appear to have been a pre-christian practice.

women obviously had a secondary status to men in pre-christian germanic society, but i don’t think they were shut away and were treated so much like “possessions” as women in most fbd societies are.

i’m goin’ with mbd marriage for pre-christian germanic tribes.

why on earth do i care? i dunno. i just got kinda stuck on the topic (in an aspergian sort-of way). i promise i’ll move on to some other groups/topics now! (^_^)

edit: boilerplate and boilerplate 2.0

previously: inbreeding amongst germanic tribes and whatever happened to european tribes?

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what happens if you marry your seventh cousin?

not very much, genetic relatedness-wise. i think it might be pretty much like marrying any random person from your ethnic group (i’m not sure — maybe someone out there knows?).

as we’ve seen, once christianity hit europe, certain bans on whom you could marry were instituted. by the sixth century, you could no longer marry your second cousin (if you were going to be a good christian, that is). later that was pushed back to the fourth cousin; and in the eleventh century, it was your sixth cousin. the regulations dropped back to fourth cousin again in the thirteenth century. those are big changes compared to pre-christian days when marrying your first cousin was prolly not uncommon.

so, how do these mating patterns affect the degree of genetic relatedness in a society?

well, looking at the standard coefficients of inbreeding for cousins, i worked out that the coefficient of inbreeding for fourth cousins is 0.000977 (that’s rounded to the sixth decimal place), and sixth cousins is 0.000015. first cousins, btw, is 0.0625.

using falconer’s coancestries recurrence equation, we can calculate, for instance, how inbred an individual is at the end of three generations of the same sort of inbreeding (e.g. first cousin marriage each generation).

if you have three successive generations of first cousins inbreeding (barring any other sort of inbreeding), the math looks like this:

Ft = 0.0625 (1 + 3Ft-1 + Ft-2)
Ft = 0.0625 (1 + 0.1875 + 0.0625) = 0.078125

so, at the end of the third generation, we get individuals with a quite higher coefficient of inbreeding than their cousin-grandparents.

fourth cousins, not so inbred:

Ft = 0.000977 (1 + 3Ft-1 + Ft-2)
Ft = 0.000977 (1 + 0.002931 + 0.000977) = 0.000981 [rounded]

seventh cousins … well, like i said, for all i know this level of inbreeding might be like that between two strangers from the same population:

Ft = 0.000015 (1 + 3Ft-1 + Ft-2)
Ft = 0.000015 (1 + 0.000045 + 0.000015) = 0.000015 [rounded]

imagine having several hundred years of such strong outbreeding. that’s some really loose genetic ties, afaics. imagine several hundred years of strong inbreeding!

here, for comparison’s sake, is what three generations of mbd marriage, the most common form of cousin marriage, looks like (male p.o.v.):

Ft = 0.0635 (1 + 3Ft-1 + Ft-2)
Ft = 0.0635 (1 + 0.1905 + 0.0635) = 0.079629

yup. more inbred than regular first-cousin cousin marriage!

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