Quantitative historical analysis uncovers a single dimension of complexity that structures global variation in human social organization.

Do human societies from around the world exhibit similarities in the way that they are structured, and show commonalities in the ways that they have evolved? These are long-standing questions that have proven difficult to answer. To test between competing hypotheses, we constructed a massive repository of historical and archaeological information known as "Seshat: Global History Databank." We systematically coded data on 414 societies from 30 regions around the world spanning the last 10,000 years. We were able to capture information on 51 variables reflecting nine characteristics of human societies, such as social scale, economy, features of governance, and information systems. Our analyses revealed that these different characteristics show strong relationships with each other and that a single principal component captures around three-quarters of the observed variation. Furthermore, we found that different characteristics of social complexity are highly predictable across different world regions. These results suggest that key aspects of social organization are functionally related and do indeed coevolve in predictable ways. Our findings highlight the power of the sciences and humanities working together to rigorously test hypotheses about general rules that may have shaped human history.

[Astrocytoma and epilepsy. Clinical case]. / Astrocitoma y epilepsia. Caso clínico.

BACKGROUND: Pilocytic astrocytoma is a rare tumour, usually occurring in paediatric ages, and mainly located in the posterior fossa. It can cause hydrocephalus and intracranial hypertension and, less frequently, seizures, or a focal neurological deficit. The main imaging study by magnetic resonance imaging, which shows a tumour with solid and cystic components without peri-lesional swelling. The election treatment is surgical, and the patient is considered cured if a total resection is accomplished. CLINICAL CASE: The case is presented of 22-year-old female patient with a supratentorial pilocytic astrocytoma and epilepsy. Histopathology reported a low grade glial proliferation, with an extensive fibrillar matrix, small cells without atypia, extensive calcifications and piloid areas consisting of bipolar fusiform cells, and some Rosenthal fibres. There were also spongiotic areas consisting of multipolar cells and associated microcysts. The final report was a pilocytic astrocytoma. CONCLUSIONS: Pilocytic astrocytoma is more frequent in paediatric patients and in the posterior fossa. The case presented is of a young female adult with supratentorial location, making it a special case. The surgery achieved a total resection. The long-term prognosis is good, but it is necessary to perform a follow-up, particularly in adult patients because of a higher risk of recurrence.