Carbon and nitrogen stable isotope ratios of bone collagen are an established method for dietary reconstruction, but this method is limited by the protein preservation. Zinc (Zn) is found in ...bioapatite and the isotopic compositions of this element constitute a very promising dietary indicator. The extent of fractionation of Zn isotopes in marine environments, however, remains unknown. We report here on the measurement of zinc, carbon and nitrogen isotopes in 47 marine mammals from the archaeological site of Arvik in the Canadian Arctic. We undertook this study to test and demonstrate the utility of Zn isotopes in recent mammal bone minerals as a dietary indicator by comparing them to other isotopic dietary tracers. We found a correlation between δ66Zn values and trophic level for most species, with the exception of walruses, which may be caused by their large seasonal movements. δ6Zn values can therefore be used as a dietary indicator in marine ecosystems for both modern and recent mammals.
The use of nurse practitioners (NPs) in primary care is one way to address growing patient demand and improve care delivery. However, little is known about trends in NP presence in primary care ...practices, or about how state policies such as scope-of-practice laws and expansion of eligibility for Medicaid may encourage or inhibit the use of NPs. We found increasing NP presence in both rural and nonrural primary care practices in the period 2008-16. At the end of the period, NPs constituted 25.2 percent of providers in rural and 23.0 percent in nonrural practices, compared to 17.6 percent and 15.9 percent, respectively, in 2008. States with full scope-of-practice laws had the highest NP presence, but the fastest growth occurred in states with reduced and restricted scopes of practice. State Medicaid expansion status was not associated with greater NP presence. Overall, primary care practices are embracing interdisciplinary provider configurations, and including NPs as providers can strengthen health care delivery.
We report here on the direct isotopic evidence for Neanderthal and early modern human diets in Europe. Isotopic methods indicate the sources of dietary protein over many years of life, and show that ...Neanderthals had a similar diet through time (almost equal to120,000 to almost equal to37,000 cal BP) and in different regions of Europe. The isotopic evidence indicates that in all cases Neanderthals were top-level carnivores and obtained all, or most, of their dietary protein from large herbivores. In contrast, early modern humans (almost equal to40,000 to almost equal to27,000 cal BP) exhibited a wider range of isotopic values, and a number of individuals had evidence for the consumption of aquatic (marine and freshwater) resources. This pattern includes Oase 1, the oldest directly dated modern human in Europe (almost equal to40,000 cal BP) with the highest nitrogen isotope value of all of the humans studied, likely because of freshwater fish consumption. As Oase 1 was close in time to the last Neanderthals, these data may indicate a significant dietary shift associated with the changing population dynamics of modern human emergence in Europe.
Radiocarbon dating is the most widely applied dating method in archaeology, especially in human evolution studies, where it is used to determine the chronology of key events, such as the replacement ...of Neanderthals by modern humans in Europe. However, the method does not always provide precise and accurate enough ages to understand the important processes of human evolution. Here we review the newest method developments in radiocarbon dating ('Radiocarbon 3.0'), which can lead us to much better chronologies and understanding of the major events in recent human evolution. As an example, we apply these new methods to discuss the dating of the important Palaeolithic site of Bacho Kiro (Bulgaria).
Prior to the introduction of wheat and barley from Central Asia during the Neolithic period, northern Chinese agricultural groups subsisted heavily on millet. Despite being the focus of many decades ...of intensive interest and research, the exact route(s), date(s), and mechanisms of the spread and adoption of wheat and barley into the existing well-established millet-based diet in northern China are still debated. As the majority of the important introduced crops are C3 plants, while the indigenous millet is C4, archaeologists can effectively identify the consumption of any introduced crops using stable carbon isotope analysis. Here we examine published stable isotope and dental caries data of human skeletal remains from 77 archaeological sites across northern and northwestern China. These sites date between 9000 to 1750 BP, encompassing the period from the beginning of agriculture to wheat's emergence as a staple crop in northern China. The aim of this study is to evaluate the implications of the spread and adoption of these crops in ancient China. Detailed analysis of human bone collagen δ13C values reveals an almost concurrent shift from a C4-based to a mixed C3/ C4- based subsistence economy across all regions at around 4500-4000 BP. This coincided with a global climatic event, Holocene Event 3 at 4200 BP, suggesting that the sudden change in subsistence economy across northern and northwestern China was likely related to climate change. Moreover, the substantially increased prevalence of dental caries from pre-to post-4000 BP indicates an increase in the consumption of cariogenic cereals during the later period. The results from this study have significant implications for understanding how the adoption of a staple crop can be indicative of large-scale environmental and socio-political changes in a region.
Consolidation of physician practices by hospitals, or vertical integration, increased across all practice types in 2007-17. Rates of growth were highest among medical and surgical specialty practices ...and lowest among primary care practices. There was substantial variation within the specialties, ranging from 4 percentage points in dermatology to 34 percentage points in cardiology and oncology.
A geostatistical model to predict human skeletal oxygen isotope values (δ
O
) in Britain is presented here based on a new dataset of Chalcolithic and Early Bronze Age human teeth. The spatial ...statistics which underpin this model allow the identification of individuals interpreted as 'non-local' to the areas where they were buried (spatial outliers). A marked variation in δ
O
is observed in several areas, including the Stonehenge region, the Peak District, and the Yorkshire Wolds, suggesting a high degree of human mobility. These areas, rich in funerary and ceremonial monuments, may have formed focal points for people, some of whom would have travelled long distances, ultimately being buried there. The dataset and model represent a baseline for future archaeological studies, avoiding the complex conversions from skeletal to water δ
O values-a process known to be problematic.
Hospitals anchor much of US health care and receive a third of all medical spending, including various subsidies. Nevertheless, some become insolvent and exit the market. Research has documented ...subsequent access problems; however, less is understood about broader implications. We examine over 100 rural hospital closures spanning 2005–2017 to quantify the effects on the local economy. We find sharp and persistent reductions in employment, but these localize to health care occupations and are more impactful in areas experiencing complete closures. Aggregate consumer financial health and housing markets appear unaffected by the shuttering of a rural hospital.
Retail health clinics (RHCs) have been described as a disruptive model of care delivery. We describe RHC market presence in the United States from 2008 to 2016 with a focus on the characteristics of ...counties where new clinics open. We merge national data on RHC openings and closings from Merchant Medicine with the Area Health Resources File. We examined county-level counts and ownership of RHCs over time. From 2008 to 2016, we found increasing ownership of RHCs by retail pharmacies, and, contrary to earlier predictions, RHCs continue to be located in affluent counties and did not open in underserved or provider shortage areas. Most new clinics opened in counties where RHCs already had a presence, and these counties also had greater primary care physician, nurse practitioner, and physician assistant density per capita (100,000). As RHCs expand and offer more services, they may place new competitive pressures on nearby primary care providers and practices.
Medicare pricing is known to indirectly influence provider prices and care provision for non-Medicare patients; however, Medicare's regulatory externalities beyond fee-setting are less well ...understood. We study how physicians’ outpatient surgery choices for non-Medicare patients responded to Medicare removing a ban on ambulatory surgery center (ASC) use for a specific procedure. Following the rule change, surgeons began reallocating both Medicare and commercially insured patients to ASCs. Specifically, physicians became 70% more likely to use ASCs for the policy-targeted procedure among their non-Medicare patients. These novel findings demonstrate that Medicare rulemaking affects physician behavior beyond the program's statutory scope.
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