Publications by authors named "John Dudgeon"

Article Synopsis
  • The study investigates ancient microbiomes in archaeological dental calculus from 102 individuals across 10 Pacific islands and one island in Southeast Asia over ~3000 years, revealing insights into human migration patterns.
  • DNA from oral microbiomes in dental calculus is better preserved than human DNA from bones, allowing for a clearer analysis of historical microbial communities.
  • The oral microbial communities from the Pacific and Island Southeast Asia are distinct from those in Europe, Africa, and Asia, indicating that geographic factors influence the composition of these ancient microbiomes.
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Remote islands in the Pacific Ocean (Oceania) experienced dramatic environmental transformations after initial human settlement in the past 3,000 yr. Here, human causality of this environmental degradation has been unquestioned and viewed as evidence of the inherent destructive tendencies of human societies in both archaeological and popular discourse. We use charcoal and stable carbon isotopes from deep soil cores to reconstruct the dynamics of fire activity and deforestation across the Sigatoka River valley on the leeward (dry) side of Viti Levu, Fiji.

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In this study, a microbial fuel cell was integrated into a hydroponic system (MFC-Hyp) using a ceramic membrane as a separator. The MFC-Hyp is a passive system that allows the transport of nutrients from wastewater in the microbial fuel cell (MFC) to water in the hydroponic vessel (Hyp) through a ceramic membrane separator, with no external energy input. The performance of this system was examined using potato-process wastewater as a source of energy and nutrients (K, P, N) and garlic chives () as a hydroponic plant.

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Article Synopsis
  • - The study examines the use of stable isotope ratio analyses in understanding the prehistoric diet of Rapa Nui, comparing bone collagen, carbonate isotopes, and compound-specific isotope analyses (CSIA) of amino acids for more accurate dietary reconstructions.
  • - Researchers analyzed carbon isotopes in bone carbonate from 28 prehistoric human teeth and modern plant samples to assess the dietary habits, revealing a primarily terrestrial diet with variable marine resource consumption over time.
  • - Findings suggest that previous assumptions of high marine food intake may need reevaluation, as they reflect the carbon assimilated rather than actual consumption; further understanding of isotopic processes and endmember values is crucial for accurate dietary assessments.
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Analyzing uranium isotopic and activity ratios can give valuable information for hydrologic and environmental studies such as insights to weathering processes, estimating water mixing ratios, and identifying water sources. The authors employed an inductively coupled plasma mass spectrometer (ICP-MS) to perform environmental level concentration measurements of isotopic uranium on 380 groundwater samples from various locations within the state of Idaho. The U:U uranium activity ratios (UAR) for these samples range between 0.

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A novel and highly sensitive nonenzymatic glucose biosensor was developed by nucleating colloidal silver nanoparticles (AgNPs) on MoS₂. The facile fabrication method, high reproducibility (97.5%) and stability indicates a promising capability for large-scale manufacturing.

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The determination of uranium concentrations in natural water samples is of great interest due to the environmental consequences of this radionuclide. In this study, 380 groundwater samples from various locations within the state of Idaho were analyzed using two different techniques. The first method was Kinetic Phosphorescence Analysis (KPA), which gives the total uranium concentrations in water samples.

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Ecological and environmental evidence suggests that Rapa Nui was among the most marginally habitable islands in Eastern Polynesia, with only a fraction of the biotic diversity found on archipelagos to the west, and capable of sustaining many fewer cultigens traditionally transported by Polynesian colonizers. However, archaeological evidence for human dietary adaptations under such restrictions is limited. Little is known about the particulars of the subsistence base and dietary changes on Rapa Nui that may be associated with a hypothesized late prehistoric decline in the quality and diversity of food sources.

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To examine possible links between neurotoxicant exposure and neuropsychological disorders and child behavior, relative concentrations of lead, mercury, and manganese were examined in prenatal and postnatal enamel regions of deciduous teeth from children with Autism Spectrum Disorders (ASDs), high levels of disruptive behavior (HDB), and typically developing (TD) children. Using laser ablation inductively coupled plasma mass spectrometry, we found no significant differences in levels of these neurotoxicants for children with ASDs compared with TD children, but there was marginal significance indicating that children with ASDs have lower manganese levels. No significant differences emerged between children with HDB and TD children.

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Objectives: To establish normal development of rod electroretinograms in preterm infants and to assess the effects of retinopathy of prematurity (ROP).

Study Design: We measured 88 Naka-Rushton functions from 41 preterm infants at maturities from 30 to 72 weeks postmenstrual age (PMA). Outcomes (log sigma, retinal sensitivity and V(max), retinal responsivity) were compared between control (no ROP), untreated ROP, and treated ROP.

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Maturation of the electroretinogram (ERG) reflects retinal development. Serial ERGs recorded from a preterm infant between 30 and 50 weeks after conception showed rapid maturation. A transient loss of retinal sensitivity coincided with clinical signs of stage 2 retinopathy of prematurity (ROP).

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