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We introduce a new system of surface integral equations for Maxwell’s transmission problem in three dimensions (3-D). This system has two remarkable features, both of which we prove. First, it is well-posed at all frequencies. Second, the underlying linear operator has a uniformly bounded inverse as the frequency approaches zero, ensuring that there is no low-frequency breakdown. The system is derived from a formulation we introduced in our previous work, which required additional integral constraints to ensure well-posedness across all frequencies. In this study, we eliminate those constraints and demonstrate that our new self-adjoint, constraints-free linear system—expressed in the desirable form of an identity plus a compact weakly-singular operator—is stable for all frequencies. Furthermore, we propose and analyze a fully discrete numerical method for these systems and provide a proof of spectrally accurate convergence for the computational method. We also computationally demonstrate the high-order accuracy of the algorithm using benchmark scatterers with curved surfaces.

The resource-poor, isolated islands of Wallacea have been considered a major adaptive obstacle for hominins expanding into Australasia. Archaeological evidence has hinted that coastal adaptations in Homo sapiens enabled rapid island dispersal and settlement; however, there has been no means to directly test this proposition. Here, we apply stable carbon and oxygen isotope analysis to human and faunal tooth enamel from six Late Pleistocene to Holocene archaeological sites across Wallacea. The results demonstrate that the earliest human forager found in the region c . 42,000 years ago made significant use of coastal resources prior to subsequent niche diversification shown for later individuals. We argue that our data provides clear insights into the huge adaptive flexibility of our species, including its ability to specialize in the use of varied environments, particularly in comparison to other hominin species known from Island Southeast Asia. There has been substantial debate of how hominins colonized Australasia through Wallacea, including their ability to utilize marine vs. terrestrial resources. Here, Roberts et al. use stable carbon and oxygen isotopes to reconstruct temporal shifts in the diets of early human inhabitants of Alor and Timor.

Remote Oceania was colonized ca. 3000 BP by populations associated with the Lapita Cultural Complex, marking a major event in the prehistoric settlement of the Pacific Islands. Although over 250 Lapita sites have been found throughout the Western Pacific, human remains associated with Lapita period sites are rare. The site of Teouma, on Efate Island, Vanuatu has yielded the largest burial assemblage (n=68 inhumations) of Lapita period humans ever discovered, providing a unique opportunity for assessing human adaptation to the environment in a colonizing population. Stable isotope ratios (δ13C, δ15N, δ34S) of human bone collagen from forty-nine Teouma adults were analyzed against a comprehensive dietary baseline to assess the paleodiet of some of Vanuatu's earliest inhabitants. The isotopic dietary baseline included both modern plants and animals (n=98) and prehistoric fauna from the site (n=71). The human stable isotope data showed that dietary protein at Teouma included a mixture of reef fish and inshore organisms and a variety of higher trophic marine (e.g. marine turtle) and terrestrial animals (e.g. domestic animals and fruit bats). The domestic pigs and chickens at Teouma primarily ate food from a C3 terrestrial environment but their δ15N values indicated that they were eating foods from higher trophic levels than those of plants, such as insects or human fecal matter, suggesting that animal husbandry at the site may have included free range methods. The dietary interpretations for the humans suggest that broad-spectrum foraging and the consumption of domestic animals were the most important methods for procuring dietary protein at the site. Males displayed significantly higher δ15N values compared with females, possibly suggesting dietary differences associated with labor specialization or socio-cultural practices relating to food distribution.

Archaeological evidence attests multiple early dispersals of Homo sapiens out of Africa, but genetic evidence points to the primacy of a single dispersal 70-40 ka. Laili in Timor-Leste is on the southern dispersal route between Eurasia and Australasia and has the earliest record of human occupation in the eastern Wallacean archipelago. New evidence from the site shows that, unusually in the region, sediment accumulated in the shelter without human occupation, in the window 59–54 ka. This was followed by an abrupt onset of intensive human habitation beginning ~44 ka. The initial occupation is distinctive from overlying layers in the aquatic focus of faunal exploitation, while it has similarities in material culture to other early Homo sapiens sites in Wallacea. We suggest that the intensive early occupation at Laili represents a colonisation phase, which may have overwhelmed previous human dispersals in this part of the world. Archaeological and genetic evidence suggest differing scenarios for human migration out of Africa. Here, the authors present archaeological evidence of intense occupation in Wallacea from 44 thousand years ago, suggesting that this occupation obscured genetic evidence of earlier dispersals.

Fish-hooks discovered among grave goods associated with an adult female burial at the Tron Bon Lei rockshelter on the island of Alor in Indonesia are the first of their kind from a Pleistocene mortuary context in Southeast Asia. Many of the hooks are of a circular rotating design. Parallels found in various other prehistoric contexts around the globe indicate widespread cultural convergence. The association of the fish-hooks with a human burial, combined with the lack of alternative protein sources on the island, suggest that fishing was an important part of the cosmology of this community. The Tron Bon Lei burial represents the earliest-known example of a culture for whom fishing was clearly an important activity among both the living and the dead.

Vanuatu was first settled ca. 3000 years ago by populations associated with the Lapita culture. Models of diet, subsistence practices, and human interaction for the Lapita and subsequent occupation periods have been developed mainly using the available archaeological and paleoenvironmental data. We test these models using stable (carbon, nitrogen, and sulfur) and radiogenic (strontium) isotopes to assess the diet and childhood residency of past communities that lived on the small (<1 km2) island of Uripiv, located off the northeast coast of Malakula, Vanuatu. The burials are from the initial Lapita occupation of the island (ca. 2800-2600 BP), the subsequent later Lapita (LL, ca. 2600-2500 BP) and post-Lapita (PL, ca. 2500-2000 BP) occupations, in addition to a late prehistoric/historic (LPH, ca. 300-150 BP) occupation period. The human stable isotope results indicate a progressively more terrestrial diet over time, which supports the archaeological model of an intensification of horticultural and arboricultural systems as local resources were depleted, populations grew, and cultural situations changed. Pig diets were similar and included marine foods during the Lapita and PL periods but were highly terrestrial during the LPH period. This dietary pattern indicates that there was little variation in animal husbandry methods during the first 800 years of prehistory; however, there was a subsequent change as animal diets became more controlled in the LPH period. After comparison with the local bioavailable 87Sr/86Sr baseline, all of the Lapita and LPH individuals appeared to be 'local', but three of the PL individuals were identified as \"non-local.\" We suggest that these \"non-locals\" moved to the island after infancy or childhood from one of the larger islands, supporting the model of a high level of regional interaction during the post-Lapita period.

The insular region of Wallacea has become a focal point for studying Pleistocene human ecological and cultural adaptations in island environments, however, little is understood about early burial traditions during the Pleistocene. Here we investigate maritime interactions and burial practices at Ratu Mali 2, an elevated coastal cave site on the small island of Kisar in the Lesser Sunda Islands of eastern Indonesia dated to 15,500–3700 cal. BP. This multidisciplinary study demonstrates extreme marine dietary adaptations, engagement with an extensive exchange network across open seas, and early mortuary practices. A flexed male and a female, interred in a single grave with abundant shellfish and obsidian at Ratu Mali 2 by 14.7 ka are the oldest known human burials in Wallacea with established funerary rites. These findings highlight the impressive flexibility of our species in marginal environments and provide insight into the earliest known ritualised treatment of the dead in Wallacea.

We report the unprecedented Lapita exploitation and subsequent extinction of large megafauna tortoises ( ?Meiolania damelipi ) on tropical islands during the late Holocene over a 281,000 km 2 region of the southwest Pacific spanning from the Vanuatu archipelago to Viti Levu in Fiji. Zooarchaeological analyses have identified seven early archaeological sites with the remains of this distinctive hornless tortoise, unlike the Gondwanan horned meiolaniid radiation to the southwest. These large tortoise radiations in the Pacific may have contributed to the rapid dispersal of early mobile Neolithic hunters throughout southwest Melanesia and on to western Polynesia. Subsequent rapid extinctions of these terrestrial herbivorous megafauna are likely to have led to significant changes in ecosystems that help explain changes in current archaeological patterns from Post-Lapita contexts in the region.

Meiolaniid or horned turtles are members of the extinct Pleistocene megafauna of Australia and the southwest Pacific. The timing and causes of their extinction have remained elusive. Here we report the remains of meiolaniid turtles from cemetery and midden layers dating 3,100/3,000 calibrated years before present to approximately 2,900/2,800 calibrated years before present in the Teouma Lapita archaeological site on Efate in Vanuatu. The remains are mainly leg bones; shell fragments are scant and there are no cranial or caudal elements, attesting to off-site butchering of the turtles. The new taxon differs markedly from other named insular terrestrial horned turtles. It is the only member of the family demonstrated to have survived into the Holocene and the first known to have become extinct after encountering humans.