Collapse and continuity: A multi-proxy reconstruction of settlement organization and population trajectories in the Northern Fertile Crescent during the 4.2kya Rapid Climate Change event

The rise and fall of ancient societies have been attributed to rapid climate change events. One of the most discussed of these is the 4.2kya event, a period of increased aridity and cooling posited as the cause of societal changes across the globe, including the collapse of the Akkadian Empire in Mesopotamia. Studies seeking to correlate social and climatic changes around the 4.2kya event have tended to focus either on highly localized analyses of specific sites or surveys or more synthetic overviews at pan-continental scales, and temporally on the event and its aftermath. Here we take an empirical approach at a large spatial scale to investigate trends in population and settlement organization across the entirety of Northern Fertile Crescent (Northern Mesopotamia and the Northern Levant) from 6,000 to 3,000 cal BP. We use Summed Probability Distributions of radiocarbon dates and data from eighteen archaeological surveys as proxies for population, and a dataset of all settlements over ten hectares in size as a proxy for the degree of urbanization. The goal is to examine the spatial and temporal impact of the 4.2kya event and to contextualize it within longer term patterns of settlement. We find that negative trends are visible during the event horizon in all three proxies. However, these occur against a long-term trend of increased population and urbanization supported through unsustainable overshoot and the exploitation of a drier zone with increased risk of crop failure. We argue that the 4.2kya event occurred during a period of unprecedented urban and rural growth which may have been unsustainable even without an exogenous climate forcing

Combined implantation of toric and spherical intraocular lenses for low corneal astigmatism correction

Background: This study compared outcomes of combined toric versus spherical intraocular lens (IOL) implantation in patients with low corneal astigmatism. Methods: In this retrospective contralateral study, patients with corneal astigmatism who received combined toric (FIL 611 T, Soleko, Rome, Italy) and spherical IOL (FIL 611 T, Soleko, Rome, Italy) implants were recruited. Eyes were examined preoperatively and then again 3 months postoperatively. Postoperatively, uncorrected distance visual acuity (UCDVA), residual astigmatism, and spherical equivalent (SE) were compared between the toric IOL-implanted eyes and the spherical IOL-implanted fellow eyes. Results: Among the 46 included cases (age 69 ± 12.7 years [mean± standard deviation]; range: 60‒78 years), 86.9% of eyes (n = 40) in the toric IOL group had a postoperative refractive cylinder of ≤ 0.25 diopters (D), compared with 4.3% (n = 2) of eyes in the spherical IOL group. Both groups showed a statistically significant reduction in refractive cylinder and improvement in UCDVA after cataract surgery (both P = 0.01). Similarly, toric IOLs were superior (69.6%) to spherical lenses (2.2%) in obtaining a SE of ≤ 0.25 D. Conclusions: To our knowledge, no previous study had sought to compare low-power toric and spherical IOLs in low corneal astigmatism in the same patient's eyes. Our findings suggest that low-power toric IOLs may result in good refractive outcomes as compared with spherical IOLs implanted in the fellow eye of the same patient, although both result in significant UCDVA improvement. Wellâ€designed clinical research studies with a longer follow-up and more participants are necessary to confirm these findings

Long-Term Demographic Trends in Prehistoric Italy: Climate Impacts and Regionalised Socio-Ecological Trajectories

The Italian peninsula offers an excellent case study within which to investigate long-term regional demographic trends and their response to climate fluctuations, especially given its diverse landscapes, latitudinal range and varied elevations. In the past two decades, summed probability distributions of calibrated radiocarbon dates have become an important method for inferring population dynamics in prehistory. Recent advances in this approach also allow for statistical assessment of spatio-temporal patterning in demographic trends. In this paper we reconstruct population change for the whole Italian peninsula from the Late Mesolithic to the Early Iron Age (10,000–2800 cal yr BP). How did population patterns vary across time and space? Were fluctuations in human population related to climate change? In order to answer these questions, we have collated a large list of published radiocarbon dates (n = 4010) and use this list firstly to infer the demographic trends for the Italian peninsula as a whole, before addressing each of five sub-regions in turn (northern, central, and southern Italy, Sicily, Sardinia). We also compare population fluctuations with local paleoclimate proxies (cave, lake, marine records). At a pan-regional scale, the results show a general rapid and substantial increase in population in the Early Neolithic with the introduction of farming at around 8000 cal yr BP and further dramatic increases during the Bronze and Iron Age (~ 3800–2800 cal yr BP). However, different regional demographic trajectories exist across different regions of Italy, suggesting a variety of localised human responses to climate shifts. Population and climate appear to have been more closely correlated during the early–mid Holocene (Mesolithic–Neolithic), while later in the Holocene (Bronze–Iron Ages) they decouple. Overall, across the Holocene the population dynamics varied by region and depended on the long-term socio-ecological dynamics prevailing in a given area. Finally, we include a brief response to the paper ‘Radiocarbon dated trends and central Mediterranean prehistory’ by Parkinson et al. (J Word Prehist 34(3), 2021)—synchronously published by Journal of World Prehistory but wholly independently developed—indicating how our conclusions accord with or differ from one another

Holocene regional population dynamics and climatic trends in the Near East: a first comparison using archaeo-demographic proxies

This paper illustrates long-term trends in human population and climate from the Late Pleistocene to the Late Holocene (14,000-2500 cal. yr. BP) in order to assess to what degree climate change impacted human societies in the Near East. It draws on a large corpus of archaeodemographic data, including anthropogenic radiocarbon dates (n=10,653) and archaeological site survey (n=22,533), and 16 hydro-climatic records from cave speleothems and lake sediments. Where possible, inferred population dynamics and climatic trends have been made spatially congruent, and their relationships have been statistically tested. Demographic proxies and paleoclimatic records have been compared for the greater Near East as a whole and for seven major geo-cultural regions (Anatolia, Arabia, Cyprus, Iran, Levant, Mesopotamia, and South Caucasus). This approach allows us to identify regionalised patterns in population and climate trends. The results suggest a clear relationship between population and climate in the Late Pleistocene and Early Holocene (14,000-8326 cal. yr. BP) with population increasing in concomitance with wetter climatic conditions. During the Middle Holocene (8326-4200 cal. yr. BP) there is an increased regionalisation of demographic patterns, followed by marked interregional contrasts in the Late Holocene (4200-2500 cal. yr. BP). We identify a decoupling of demographic and climatic trends from the Middle Holocene onwards, and relate this to the existence of more complex societies. These were less vulnerable to gradual climatic shifts due to their logistical infrastructure, social organisation and technological capacity. We also assess the impact of five Rapid Climate Changes (RCC) which occurred during the study period on population levels. Although all five RCC (the so-called 10.2 k, 9.2 k, 8.2 k, 4.2 k, and 3.2 k cal. yr. BP events) are visible to some degree in our palaeoclimatic and demographic proxies, there are marked regional variations in magnitude and duration

Seshat: The Global History Databank

The vast amount of knowledge about past human societies has not been systematically organized and, therefore, remains inaccessible for empirically testing theories about cultural evolution and historical dynamics. For example, what evolutionary mechanisms were involved in the transition from the small-scale, uncentralized societies, in which humans lived 10,000 years ago, to the large-scale societies with an extensive division of labor, great differentials in wealth and power, and elaborate governance structures of today? Why do modern states sometimes fail to meet the basic needs of their populations? Why do economies decline, or fail to grow? In this article, we describe the structure and uses of a massive databank of historical and archaeological information, Seshat: The Global History Databank. The data that we are currently entering in Seshat will allow us and others to test theories explaining how modern societies evolved from ancestral ones, and why modern societies vary so much in their capacity to satisfy their members’ basic human needsPeer reviewedFinal Published versio

One-Handed Rotational Phacoemulsification Technique

Introduction: We described a one-handed rotational phacoemulsification technique to decrease phaco time and power, and surgical stress on the cornea in eyes with different types of cataract. Methods: In this technique a single sutureless corneal incision was made without any side-port incision. After hydrodissection and hydrodelamination were performed, a phaco tip was positioned in contact with the nucleus beside the capsulorhexis edge. By using a peristaltic pump, phacoemulsification was started with high levels of vacuum to keep the probe tip on the edge of the lens and to ensure the rotation of the nucleus, and with low ultrasound energy. The torsional mode used required less occlusion time and volume of fluid. The inclination of the tip was modified to 45-degree, directing it toward the lens center. So the nucleus was aspirated from the periphery toward the center by a rotational movement. Results: The eye in the technical video had a NC4-NO4 cataract. The preoperative vision in this eye was 20/100 with no improvement with refraction. On postoperative day 1, visual acuity had improved to 20/20. We recorded low intraoperative parameters including ultrasound time (21.4 sec), phacoemulsification power (73%), balanced salt solution used (31 mL) and cumulative dissipated energy (7.27) at the conclusion of the case. After 1 month, Central Corneal Thickness changed from 504 µm to 516 µm, and Endothelial Cell Loss was 1.15%. Conclusion: This technique uses a single clear corneal incision, high vacuum and low ultrasound power to reduce the exposition to excessive surgical maneuvers, fluid turbulence and ultrasound energy