Sedimentary ancient DNA reveals the impact of anthropogenic land use disturbance and ecological shifts on fish community structure in small lowland lake

Freshwater fish biodiversity and abundance are decreasing globally. The drivers of decline are primarily anthropogenic; however, the causative links between disturbances and fish community change are complex and challenging to investigate. We used a suite of sedimentary DNA methods (droplet digital PCR and metabarcoding) and traditional paleolimnological approaches, including pollen and trace metal analysis, ITRAX X-ray fluorescence and hyperspectral core scanning to explore changes in fish abundance and drivers over 1390 years in a small lake. This period captured a disturbance trajectory from pre-human settlement through subsistence living to intensive agriculture. Generalized additive mixed models explored the relationships between catchment inputs, internal drivers, and fish community structure. Fish community composition distinctly shifted around 1350 CE, with the decline of a sensitive Galaxias species concomitant with early land use changes. Total fish abundance significantly declined around 1950 CE related to increases in ruminant bacterial DNA (a proxy for ruminant abundance) and cadmium flux (a proxy for phosphate fertilizers), implicating land use intensification as a key driver. Concurrent shifts in phytoplankton and zooplankton suggested that fish communities were likely impacted by food web dynamics. This study highlights the potential of sedDNA to elucidate the long-term disturbance impacts on biological communities in lakes.

Holocene global mean surface temperature, a multi-method reconstruction approach

An extensive new multi-proxy database of paleo-temperature time series (Temperature 12k) enables a more robust analysis of global mean surface temperature (GMST) and associated uncertainties than was previously available. We applied five different statistical methods to reconstruct the GMST of the past 12,000 years (Holocene). Each method used different approaches to averaging the globally distributed time series and to characterizing various sources of uncertainty, including proxy temperature, chronology and methodological choices. The results were aggregated to generate a multi-method ensemble of plausible GMST and latitudinal-zone temperature reconstructions with a realistic range of uncertainties. The warmest 200-year-long interval took place around 6500 years ago when GMST was 0.7 °C (0.3, 1.8) warmer than the 19th Century (median, 5th, 95th percentiles). Following the Holocene global thermal maximum, GMST cooled at an average rate -0.08 °C per 1000 years (-0.24, -0.05). The multi-method ensembles and the code used to generate them highlight the utility of the Temperature 12k database, and they are now available for future use by studies aimed at understanding Holocene evolution of the Earth system.

A global database of Holocene paleotemperature records

A comprehensive database of paleoclimate records is needed to place recent warming into the longer-term context of natural climate variability. We present a global compilation of quality-controlled, published, temperature-sensitive proxy records extending back 12,000 years through the Holocene. Data were compiled from 679 sites where time series cover at least 4000 years, are resolved at sub-millennial scale (median spacing of 400 years or finer) and have at least one age control point every 3000 years, with cut-off values slackened in data-sparse regions. The data derive from lake sediment (51%), marine sediment (31%), peat (11%), glacier ice (3%), and other natural archives. The database contains 1319 records, including 157 from the Southern Hemisphere. The multi-proxy database comprises paleotemperature time series based on ecological assemblages, as well as biophysical and geochemical indicators that reflect mean annual or seasonal temperatures, as encoded in the database. This database can be used to reconstruct the spatiotemporal evolution of Holocene temperature at global to regional scales, and is publicly available in Linked Paleo Data (LiPD) format.

Consistent multi-decadal variability in global temperature reconstructions and simulations over the Common Era

Multi-decadal surface temperature changes may be forced by natural as well as anthropogenic factors, or arise unforced from the climate system. Distinguishing these factors is essential for estimating sensitivity to multiple climatic forcings and the amplitude of the unforced variability. Here we present 2,000-year-long global mean temperature reconstructions using seven different statistical methods that draw from a global collection of temperature-sensitive paleoclimate records. Our reconstructions display synchronous multi-decadal temperature fluctuations, which are coherent with one another and with fully forced CMIP5 millennial model simulations across the Common Era. The most significant attribution of pre-industrial (1300-1800 CE) variability at multi-decadal timescales is to volcanic aerosol forcing. Reconstructions and simulations qualitatively agree on the amplitude of the unforced global mean multi-decadal temperature variability, thereby increasing confidence in future projections of climate change on these timescales. The largest warming trends at timescales of 20 years and longer occur during the second half of the 20^th century, highlighting the unusual character of the warming in recent decades.

Land carbon models underestimate the severity and duration of drought's impact on plant productivity

The ability to accurately predict ecosystem drought response and recovery is necessary to produce reliable forecasts of land carbon uptake and future climate. Using a suite of models from the Multi-scale Synthesis and Terrestrial Model Intercomparison Project (MsTMIP), we assessed modeled net primary productivity (NPP) response to, and recovery from, drought events against a benchmark derived from tree ring observations between 1948 and 2008 across forested regions of the US and Europe. We find short lag times (0-6 months) between climate anomalies and modeled NPP response. Although models accurately simulate the direction of drought legacy effects (i.e. NPP decreases), projected effects are approximately four times shorter and four times weaker than observations suggest. This discrepancy between observed and simulated vegetation recovery from drought reveals a potential critical model deficiency. Since productivity is a crucial component of the land carbon balance, models that underestimate drought recovery time could overestimate predictions of future land carbon sink strength and, consequently, underestimate forecasts of atmospheric CO₂.

Pseudo myocardial infarction

The case is presented of a 66 year old woman who attended the emergency department with severe abdominal pain subsequent to a bout of coughing, following a week's history of productive cough. She was known to have chronic obstructive pulmonary disease and was also on warfarin for recurrent deep vein thromboses. She had no history of ischaemic heart disease. She was found to have a rectus sheath haematoma and an international normalised ratio of 7.7, and admission was arranged for coagulation control and analgesia. However, a routine electrocardiograph (ECG) demonstrated an ST elevation pattern consistent with an acute inferior infarction. Subsequent ECGs showed no ST elevation, although the axis and chest lead QRS morphology remained the same throughout the first 12 hours. Over the next three days, R wave progression decreased in the chest leads. Troponin I at admission and 24 hours later were both <0.2 ng/ml. ECG changes compatible with acute myocardial infarction have been reported in association with a number of non-cardiac presentations; however, to our knowledge, it has never been reported in relation to a rectus sheath haematoma. We speculated on the possible mechanism of such "pseudo myocardial infarction" and the importance of treating the patient, not the ECG.

A case of dextrocardiac ventricular fibrillation arrest

Successful defibrillation of a patient with dextrocardia using conventional anterolateral paddle positions raises doubts about the necessity to place paddles in the exact recommended positions. Evidence found relates either to volunteers in a laboratory setting or to defibrillation of atrial arrhythmias. The conclusion is that there is no published difference either in transthoracic impedance or in success of defibrillation between anteroposterior and anterolateral paddle positions. In the absence of any evidence for an ideal apical paddle position in the standard anterolateral defibrillation of ventricular arrhythmias, the emphasis in ALS and resuscitation guidelines on "correct" positioning seems misplaced, and, by adding unnecessary information, may hinder learning the skill of defibrillation. Early defibrillation is crucial to successful recovery from cardiac arrest and anything that delays cardioversion should be avoided. The limited evidence suggests that the exact position of the paddles does not matter. The time taken to find the "correct" position is time wasted and it may instead be preferable to teach people merely to place the apical paddle to the left of the nipple in the midaxillary line.

Rabies: a review of UK management

Rabies is endemic worldwide, and causes approximately 30 000 deaths per year. In the past 20 years, 12 deaths have occurred in the UK, although all but one case were contracted overseas. We have reviewed the current literature regarding the management of possible rabies exposure in the setting of a UK emergency department. The article offers an overview of rabies, including pathology, risk assessment, and current treatment, including both pre-exposure and post-exposure prophylaxis. We have also included a form online, which allows the correct information to be obtained and recorded prior to seeking advice from the local virology services.

Special considerations for the pediatric perioperative patient. A developmental approach

Children are not just small adults. They have unique differences and needs both physiologically and psychosocially. The pediatric perioperative nurse is challenged to meet these needs by incorporating a knowledge of growth and development in all aspects of the plan of care.

A new robust index for measuring isokinetic trunk flexion and extension. Outcome from a regional study

The purpose of this study was 1) to provide normative data for isokinetic trunk strength as measured by peak torque, best work repetition, and a new composite variable, "muscle performance index"; and 2) to examine the effects of protocol velocity, subject age, gender, height, and weight on these measurements. A significant decrease in peak torque of extension for females (P less than 0.0001) was seen as protocol velocity increased, but no differences were seen in males. A statistically significant amount (0.5-0.7) of the variance in isokinetic measurements was explained by subject age, height, and weight. Multivariant analysis of covariance showed the effects of these variances to be significant on all measurements except for the muscle performance index, which was unaffected by protocol velocity and remained stable without adjustments for subject age, weight, or height.

Lacticacidaemia due to pyruvate dehydrogenase deficiency, with evidence of protein polymorphism in the alpha-subunit of the enzyme

In three infants with neonatal lacticacidaemia, a deficiency in the E1 (pyruvate dehydrogenase) component of the pyruvate dehydrogenase complex was demonstrated in skin fibroblast cultures. Residual activities of the pyruvate dehydrogenase complex in the activated state were 1.6%, 3.9% and 18.8% of control values, respectively. Immunoprecipitation of extracts of cultures skin fibroblasts grown on 35S-methionine with anti-pyruvate dehydrogenase complex antibody revealed an abnormality in the E1 alpha-component of these three patients when visualised after sodium dodecyl sulphate/polyacrylamide gel electrophoresis. This component appeared to have a slightly lower molecular weight than did this protein from control cell strains. Cell strains from other patients with a deficiency of the pyruvate dehydrogenase complex did not exhibit this defect. Three patients also showed dysmorphism and developmental abnormalities of the central nervous system.

Defective intramitochondrial NADH oxidation in skin fibroblasts from an infant with fatal neonatal lacticacidemia

A small-for-gestational-age female infant born at term developed severe lactic acidosis and died on day 13 of life. Two previous sibs had also died of overwhelming lactic acidosis in the neonatal period. The lactate-to-pyruvate and 3-hydroxybutyrate-to-acetoacetate ratios were elevated at 136 and 42 to one, respectively. The activities of the pyruvate dehydrogenase complex and pyruvate carboxylase in cultured skin fibroblasts were normal but a defect in respiration was indicated by the low rates of conversion of 1-[14C]pyruvate, glutamate, and lactate to 14CO2 in these cells. Skin fibroblast cultures also displayed an elevated lactate-to-pyruvate ratio (72:1) when incubated with glucose as substrate compared to control cell cultures (20:1). When mitochondrial preparations of skin fibroblasts (prepared by digitonin extraction) were tested for their ability to synthesize ATP from a variety of substrates, it was found that those of the patient made adequate amounts of ATP with either succinate or ascorbate/tetramethyl-phenylenediamine as substrate but not with the NAD-linked substrates pyruvate, isocitrate, and palmitoyl carnitine. We propose that this is indicative of a defect in the respiratory chain between NADH and coenzyme Q, for the first time demonstrable in cultured skin fibroblasts.