Landesque capital as an alternative to food storage in Melanesia: Irrigated taro terraces in New Georgia, Solomon Islands

In the Pacific islands, subsistence diversity made possible continuous production of food while welldeveloped exchange networks redistributed these foodstuffs as well as items within the prestige economy. All these were aspects of the ‘storage structures’ that enabled social and nutritional value to be saved, accumulated and later mobilised. In addition, there were investments in the land, landesque capital, which secured future food surpluses and so provided an alternative to food storage, in a region where the staple foods were mostly perishable, yams excepted, and food preservation was difficult. Landesque capital included such long-term improvements to productivity as terraces, mounds, irrigation channels, drainage ditches, soil structural changes and tree planting. These investments provided an effective alternative to food storage and made possible surplus production for exchange purposes. As an example, in the New Georgia group of the western Solomon Islands irrigated terraces, termed ruta, were constructed for growing the root crop taro (Colocasia esculenta). Surplus taro from ruta enabled inland groups to participate in regional exchange networks and so obtain the shell valuables that were produced by coastal groups. In this paper, we reconstruct how this exchange system worked in New Georgia using ethno-archaeological evidence, we chart its prehistoric rise and post-colonial fall, and we outline the factors that constrained its long-term expansion.Our gratitude for support during earlier fieldwork in the New Georgia group has already been expressed in previous publications. The 2014 project was supported by the Smuts Fund and Foreign Travel Fund, University of Cambridge, and by St John’s College, Cambridge.This is the accepted manuscript. The final version is available from Maney at http://dx.doi.org/10.1179/1749631414Y.000000004

Riverbed sediments buffer phosphorus concentrations downstream of sewage treatment works across the River Wensum catchment, UK

Purpose: Wastewater effluent discharged into rivers from sewage treatment works (STWs) represents one of the most important point sources of soluble reactive phosphorus (SRP) pollution and is a major driver of freshwater eutrophication. In this study, we assess the ability of riverbed sediments to act as a self-regulating buffering system to reduce SRP dissolved in the water column downstream of STW outflows. Materials and methods: River water and riverbed sediment samples were collected from 10 tributary outlets across the River Wensum catchment, Norfolk, UK, at monthly intervals between July and October 2016, such that 40 sediment and 40 water samples were collected in total. Of these locations, five were located downstream of STWs and five were on tributaries without STWs. Dissolved SRP concentrations were analysed and the Equilibrium Phosphorus Concentration (EPC0) of each sediment sample was measured to determine whether riverbed sediments were acting as net sources or sinks of SRP. Results and discussion: The mean SRP concentration downstream of STWs (382 µg P L-1) was double that of sites without a STW (185 µg P L-1), whilst the mean EPC0 for effluent impacted sites (105 µg P L-1) was 70% higher than that recorded at unaffected sites (62 µg P L-1). Regardless of STW influence, riverbed sediments across all 10 sites almost always acted as net sinks for SRP from the overlying water column. This was particularly true at sites downstream of STWs which displayed enhanced potential to buffer the river against increases in SRP released in sewage effluent. Conclusions: Despite EPC0 values revealing riverbed sediments were consistently acting as sinks for SRP, elevated SRP concentrations downstream of STWs clearly demonstrate the sediments have insufficient SRP sorption capacity to completely buffer the river against effluent discharge. Consequently, SRP concentrations across the catchment continue to exceed recommended standards for good chemical status, thus emphasising the need for enhanced mitigation efforts at STWs to minimise riverine phosphorus loading

From existing in situ, high-resolution measurement technologies to lab-on-a-chip – the future of water quality monitoring?

Abstract. This paper introduces new insights into the hydrochemical functioning of lowland river-systems using field-based spectrophotometric and electrode technologies. The streamwater concentrations of nitrogen species and phosphorus fractions were measured at hourly intervals on a continuous basis at two contrasting sites on tributaries of the River Thames, one draining a rural catchment, the River Enborne, and one draining a more urban system, The Cut. The measurements complement those from an existing network of multi-parameter water quality sondes maintained across the Thames catchment and weekly monitoring based on grab samples. The results of the sub-daily monitoring show that streamwater phosphorus concentrations display highly complex, seemingly chaotic, dynamics under storm conditions dependent on the antecedent catchment wetness, and that diurnal phosphorus and nitrogen cycles occur under low flow conditions. The diurnal patterns highlight the dominance of sewage inputs in controlling the streamwater phosphorus and nitrogen concentrations at low flows, even at a distance of 7 km from the nearest sewage works in the rural, River Enborne, and that the time of sample collection is important when judging water quality against ecological thresholds or standards. An exhaustion of the supply of phosphorus from diffuse and septic tank sources during storm events was evident and load estimation was not improved by sub-daily monitoring beyond that achieved by daily sampling because of the eventual reduction in the phosphorus mass entering the stream during events. The dominance of respiration over photosynthesis in The Cut indicated a prevalence of heterotrophic algae, and the seasonal patterns in respiration and photosynthesis corresponded with those of temperature and light in this nutrient over-enriched stream. These results highlight the utility of sub-daily water quality measurements but the deployment of modified wet-chemistry technologies into the field was limited by mains electricity availability. A new approach is therefore needed to allow measurement of a wide range of analytes at a broader range of locations for the development of water quality web-sensor networks. The development and field deployment of a miniaturised "lab-on-a-chip" ion chromatograph is proposed and justified. </jats:p

Investigating the effects of mobile bottom fishing on benthic carbon processing and storage : a systematic review protocol

Background Marine sediments represent one of the planet’s largest carbon stores. Bottom trawl fisheries constitute the most widespread physical disturbance to seabed habitats, which exert a large influence over the oceanic carbon dioxide (CO2) sink. Recent research has sparked concern that seabed disturbance from trawling can therefore turn marine sediments into a large source of CO2, but the calculations involved carry a high degree of uncertainty. This is primarily due to a lack of quantitative understanding of how trawling mixes and resuspends sediments, how it alters bioturbation, bioirrigation, and oxygenation rates, and how these processes translate into carbon fluxes into or out of sediments. Methods The primary question addressed by this review protocol is: how does mobile bottom fishing affect benthic carbon processing and storage? This question will be split into the following secondary questions: what is the effect of mobile bottom fishing on: (i) the amount and type of carbon found in benthic sediments; (ii) the magnitude and direction of benthic-pelagic carbon fluxes; (iii) the biogeochemical, biological, and physical parameters that control the fate of benthic carbon; and (iv) the biogeochemical, biological, and physical parameters that control the fate of resuspended carbon. Literature searches will be conducted in Web of Science, SCOPUS, PROQUEST, and a range of grey and specialist sources. An initial scoping search in Web of Science informed the final search string, which has been formulated according to Population Intervention Comparator Outcome (PICO) principles. Eligible studies must contain data concerning a change in a population of interest caused by mobile bottom fishing. Eligible study designs are Before and After, Control and Impact, and Gradient studies. Studies included at full-text screening will be critically appraised, and study findings will be extracted.Extracted data will be stored in an Excel spreadsheet. Results will be reported in narrative and quantitative syntheses using a variety of visual tools including forest plots. Meta-analysis will be conducted where sufficient data exists

Estimating parent population of pottery vessels from a sample of fragments: a case study from inter-tidal surface collections, Roviana Lagoon, Solomon Islands

Archaeologists frequently interpret the duration and type of prehistoric occupation at a location/site from the relative abundance of prehistoric materials (accumulations research). Taphonomic factors have the potential to alter substantially the archaeological record leading to inaccurate assumptions about the nature of prehistoric settlement. Where vessel families of potsherds can be established, we provide a general method to estimate the parent population from which the sample of sherds derives, through analysis of vessel completeness of the sample. This provides a basis for archaeological interpretation of the scale of discard represented at a location. The approach used has broad applicability to many archaeological settings where behavioural inferences are made from poorly preserved ceramic samples. Statistical analysis of a ceramic assemblage from Roviana Lagoon stilt villages indicates that most of the ceramic assemblage has been destroyed over time. An unexpectedly severe taphonomic regime is inferred for this relatively sheltered landlocked lagoon setting. Rather than marking an ephemeral occupation, estimating a parent ceramic population indicates instead that early stilt village sites in the Solomon Islands region were probably permanently occupied for several centuries. Results also suggest that the relative absence of recorded Lapita sites in the main Solomon Islands, and possibly elsewhere in Near Oceania may be a result of a harsh taphonomic regime for the remains of stilt village occupation

Diabetic ketoacidosis - A possible complicating factor in deaths associated with drug overdose: Two case reports

Two cases are described where diabetic ketoacidosis was found in conjunction with significant levels of prescription drugs. Case 1: A 45-year-old woman with a history of insulin-dependent diabetes mellitus was found to have Armanni-Ebstein nephropathy characteristic of hyperglycaemia with a vitreous humour glucose level of 63.1 mmol/L and a beta-hydroxybutyrate level of 14.25 mmol/L. Ancillary toxicological evaluation revealed a lethal level of sertraline (2.5 mg/L), with an elevated level of methadone (0.23mg/L). Death was due to diabetic ketoacidosis complicating mixed drug toxicity. Case 2: A 27-year-old man with a history of insulin-dependent diabetes mellitus was found to have Armanni-Ebstein nephropathy with a vitreous humour glucose level of 51.7 mmol/L and a beta-hydroxybutyrate level of 18.6mmol/L. Ancillary toxicological evaluation revealed a potentially lethal level of methadone of 0.39mg/L. Death was attributed to diabetic ketoacidosis complicating methadone toxicity. These cases demonstrate a situation where drug toxicity led to diabetic ketoacidosis resulting in death most likely from a combination of factors. Measuring vitreous humour glucose and beta-hydroxybutyrate levels is important in individuals with histories, or scene evidence, of insulin-dependent diabetes mellitus, in addition to toxicological screening when there is evidence of possible drug taking. It appears that drug intoxication in both cases had impaired the ability to administer insulin, resulting in the development over time of diabetic ketoacidotic states. Lethal mechanisms were, therefore, more complex than simple drug toxicity or diabetic ketoacidosis in isolation

Diabetic Ketoacidosis – A possible Complicating Factor in Deaths associated with Drug Overdose

Two cases are described where diabetic ketoacidosis was found in conjunction with significant levels of prescription drugs. Case 1: A 45-year-old woman with a history of insulin-dependent diabetes mellitus was found to have Armanni-Ebstein nephropathy characteristic of hyperglycaemia with a vitreous humour glucose level of 63.1 mmol/L and a β-hydroxybutyrate level of 14.25 mmol/L. Ancillary toxicological evaluation revealed a lethal level of sertraline (2.5 mg/L), with an elevated level of methadone (0.23 mg/L). Death was due to diabetic ketoacidosis complicating mixed drug toxicity. Case 2: A 27-year-old man with a history of insulin-dependent diabetes mellitus was found to have Armanni-Ebstein nephropathy with a vitreous humour glucose level of 51.7 mmol/L and a β-hydroxybutyrate level of 18.6 mmol/L. Ancillary toxicological evaluation revealed a potentially lethal level of methadone of 0.39 mg/L. Death was attributed to diabetic ketoacidosis complicating methadone toxicity. These cases demonstrate a situation where drug toxicity led to diabetic ketoacidosis resulting in death most likely from a combination of factors. Measuring vitreous humour glucose and β-hydroxybutyrate levels is important in individuals with histories, or scene evidence, of insulin-dependent diabetes mellitus, in addition to toxicological screening when there is evidence of possible drug taking. It appears that drug intoxication in both cases had impaired the ability to administer insulin, resulting in the development over time of diabetic ketoacidotic states. Lethal mechanisms were, therefore, more complex than simple drug toxicity or diabetic ketoacidosis in isolation. </jats:p

Solute transport via the new permeability pathways in Plasmodium falciparum-infected human red blood cells is not consistent with a simple single-channel model

After infection of a red blood cell (RBC), the malaria parasite, Plasmodium falciparum, increases the permeability of the host’s plasma membrane by inducing new permeability pathways (NPPs). Single-channel patch-clamp experiments have shown the presence in infected RBCs of novel anion-selective channel types with low open-state probabilities at positive membrane potentials. These channels have been postulated to form the NPPs. Here, we have used a range of transport techniques to study whether electroneutral solutes use these channels or altered/separate pathways. Transport of the electroneutral solute sorbitol via the NPPs was found to increase by a small but significant amount after gross membrane depolarization. This is inconsistent with transport via a channel with a reduced open-state probability at positive membrane potentials. As has been demonstrated previously for parasite-induced anion currents, sorbitol transport in infected RBCs was found to be sensitive to the presence of bovine serum albumin (BSA). However, it remains to be shown whether the effect is due to serum/BSA altering a single channel type or activating a new pathway. In addition, the study highlights problems that can occur when using different transport techniques to study the NPPs