Assessing sampling of the fossil record in a geographically and stratigraphically constrained dataset: the Chalk Group of Hampshire, southern UK

Taphonomic, geological and sampling processes have been cited as biasing richness measurements in the fossil record, and sampling proxies have been widely used to assess this. However, the link between sampling and taxonomic richness is poorly understood, and there has been much debate on the equivalence and relevance of proxies. We approach this question by combining both historical and novel data: a historical fossil occurrence dataset with uniquely high spatial resolution from the Upper Cretaceous Chalk Group of Hampshire, UK, and a newly compiled 3D geological model that maps subsurface extent. The geological model provides rock volumes, and these are compared with exposure and outcrop area, sampling proxies that have often been conflated in previous studies. The extent to which exposure area (true rock availability) has changed over research time is also tested. We find a trend of low Cenomanian to high Turonian to Campanian raw richness, which correlates with, and is possibly driven by, the number of specimens found. After sampling standardization, an unexpected mid-Turonian peak diversity is recovered, and sampling-standardized genus richness is best predicted by rock volume, suggesting a species–area (or ‘genus–area’) effect. Additionally, total exposure area has changed over time, but relative exposure remains the same. Supplementary materials: A locality list, abundance matrix and all correlation and modelling results are available at https://doi.org/10.6084/m9.figshare.c.3592208

Assessing sampling of the fossil record in a geographically and stratigraphically constrained dataset: the Chalk Group of Hampshire, southern UK

Taphonomic, geological and sampling processes have been cited as biasing richness measurements in the fossil record, and sampling proxies have been widely used to assess this. However, the link between sampling and taxonomic richness is poorly understood, and there has been much debate on the equivalence and relevance of proxies. We approach this question by combining both historical and novel data: a historical fossil occurrence dataset with uniquely high spatial resolution from the Upper Cretaceous Chalk Group of Hampshire, UK, and a newly compiled 3D geological model that maps subsurface extent. The geological model provides rock volumes, and these are compared with exposure and outcrop area, sampling proxies that have often been conflated in previous studies. The extent to which exposure area (true rock availability) has changed over research time is also tested. We find a trend of low Cenomanian to high Turonian to Campanian raw richness, which correlates with, and is possibly driven by, the number of specimens found. After sampling standardization, an unexpected mid-Turonian peak diversity is recovered, and sampling-standardized genus richness is best predicted by rock volume, suggesting a species–area (or ‘genus–area’) effect. Additionally, total exposure area has changed over time, but relative exposure remains the same. Supplementary materials: A locality list, abundance matrix and all correlation and modelling results are available at https://doi.org/10.6084/m9.figshare.c.3592208

Ammonium recycling supports toxic Planktothrix blooms in Sandusky Bay, Lake Erie: Evidence from stable isotope and metatranscriptome data

Sandusky Bay, Lake Erie, receives high nutrient loadings (nitrogen and phosphorus) from the Sandusky River, which drains an agricultural watershed. Eutrophication and cyanobacterial harmful algal blooms (cyanoHABs) persist throughout summer. Planktothrix agardhii is the dominant bloom-forming species and the main producer of microcystins in Sandusky Bay. Non-N2 fixing cyanobacteria, such as Planktothrix and Microcystis, thrive on chemically reduced forms of nitrogen, such as ammonium (NH4+) and urea. Ammonium regeneration and potential uptake rates and total microbial community demand for NH4+ were quantified in Sandusky Bay. Potential NH4+ uptake rates in the light increased from June to August at all stations. Dark uptake rates also increased seasonally and, by the end of August, were on par with light uptake rates. Regeneration rates followed a similar pattern and were significantly higher in August than June. Ammonium uptake kinetics during a Planktothrix-dominated bloom in Sandusky Bay and a Microcystis-dominated bloom in Maumee Bay were also compared. The highest half saturation constant (Km) in Sandusky Bay was measured in June and decreased throughout the season. In contrast, Km values in Maumee Bay were lowest at the beginning of summer and increased in October. A significant increase in Vmax in Sandusky Bay was observed between July and the end of August, reflective of intense competition for depleted NH4+. Metatranscriptome results from Sandusky Bay show a shift from cyanophycin synthetase (luxury NH4+ uptake; cphA1) expression in early summer to cyanophycinase (intracellular N mobilization; cphB/cphA2) expression in August, supporting the interpretation that the microbial community is nitrogen-starved in late summer. Combined, our results show that, in late summer, when nitrogen concentrations are low, cyanoHABs in Sandusky Bay rely on regenerated NH4+ to support growth and toxin production. Increased dark NH4+ uptake late in summer suggests an important heterotrophic contribution to NH4+ depletion in the phycosphere. Kinetic experiments in the two bays suggest a competitive advantage for Planktothrix over Microcystis in Sandusky Bay due to its higher affinity for NH4+ at low concentrations

Tunable microwave signal generator with an optically-injected 1310nm QD-DFB laser

Tunable microwave signal generation with frequencies ranging from below 1 GHz to values over 40 GHz is demonstrated experimentally with a 1310nm Quantum Dot (QD) Distributed-Feedback (DFB) laser. Microwave signal generation is achieved using the period 1 dynamics induced in the QD DFB under optical injection. Continuous tuning in the positive detuning frequency range of the quantum dot's unique stability map is demonstrated. The simplicity of the experimental configuration offers promise for novel uses of these nanostructure lasers in Radio-over-Fiber (RoF) applications and future mobile networks. © 2013 Optical Society of America

Mapping pneumonia research: a systematic analysis of UK investments and published outputs 1997–2013

BackgroundThe burden of pneumonia continues to be substantial, particularly among the poorest in global society. We describe here the trends for UK pneumonia R&D investment and published outputs, and correlate with 2013 global mortality.MethodsData related to awards to UK institutions for pneumonia research from 1997 to 2013 were systematically sourced and categorised by disease area and type of science. Investment was compared to mortality figures in 2010 and 2013 for pneumonia, tuberculosis and influenza. Investment was also compared to publication data.ResultsOf all infectious disease research between 2011 and 2013 (£917.0 million), £28.8 million (3.1%) was for pneumonia. This was an absolute and proportionate increase from previous time periods. Translational pneumonia research (33.3%) received increased funding compared with 1997–2010 where funding was almost entirely preclinical (87.5%, here 30.9%), but high-burden areas such as paediatrics, elderly care and antimicrobial resistance received little investment. Annual investment remains volatile; publication temporal trends show a consistent increase. When comparing investment to global burden with a novel ‘investment by mortality observed’ metric, tuberculosis (£48.36) and influenza (£484.21) receive relatively more funding than pneumonia (£43.08), despite investment for pneumonia greatly increasing in 2013 compared to 2010 (£7.39). Limitations include a lack of private sector data and the need for careful interpretation of the comparisons with burden, plus categorisation is subjective.ConclusionsThere has been a welcome increase for pneumonia funding awarded to UK institutions in 2011–2013 compared with 1997–2010, along with increases for more translational research. Published outputs relating to pneumonia rose steadily from 1997 to 2013. Investment relative to mortality for pneumonia has increased, but it remains low compared to other respiratory infections and clear inequities remain. Analyses that measure investments in pneumonia can provide an insight into funding trends and research gaps.Research in contextPneumonia continues to be a high-burden illness around the globe. This paper shows that although research funding is increasing in the UK (between 1997 and 2013), it remains poorly funded compared to other important respiratory infectious diseases such as tuberculosis and influenza. Publications about pneumonia have been steadily increasing over time, indicating continuing academic and clinical interest in the topic. Though global mortality of pneumonia is declining, it should still be an area of high priority for funders, policymakers and researchers

Echocardiographic assessment of patients with infectious endocarditis: Prediction of risk for complications

AbstractTo enhance the echocardiographic identification of high risk lesions in patients with infectious endocarditis, the medical records and two-dimensional echocardiograms of 204 patients with this condition were analyzed. The occurrence of specific clinical complications was recorded and vegetations were assessed with respect to predetermined morphologic characteristics.The overall complication rates were roughly equivalent for patients with mitral (53%), aortic (62%), tricuspid (77%) and prosthetic valve (61%) vegetations, as well as for those with nonspecific valvular changes but no discrete vegetations (57%), although the distribution of specific complications varied considerably among these groups. There were significantly fewer complications in patients without discernible valvular abnormalities (27%).In native left-sided valve endocarditis, vegetation size, extent, mobility and consistency were all found to be significant univariate predictors of complications. In multivariate analysis, vegetation size, extent and mobility emerged as optimal predictors and an echocardiographic score based on these factors predicted the occurrence of complications with 70% sensitivity and 92% specificity in mitral valve endocarditis and with 76% sensitivity and 62% specificity in aortic valve endocarditis

Altered fluvial patterns in North China indicate rapid climate change linked to the Permian-Triassic mass extinction

The causes of the severest crisis in the history of life around the Permian-Triassic boundary (PTB) remain controversial. Here we report that the latest Permian alluvial plains in Shanxi, North China, went through a rapid transition from meandering rivers to braided rivers and aeolian systems. Soil carbonate carbon isotope (δ13C), oxygen isotope (δ18O), and geochemical signatures of weathering intensity reveal a consistent pattern of deteriorating environments (cool, arid, and anoxic conditions) and climate fluctuations across the PTB. The synchronous ecological collapse is confirmed by a dramatic reduction or disappearance of dominant plants, tetrapods and invertebrates and a bloom of microbially-induced sedimentary structures. A similar rapid switch in fluvial style is seen worldwide (e.g. Karoo Basin, Russia, Australia) in terrestrial boundary sequences, all of which may be considered against a background of global marine regression. The synchronous global expansion of alluvial fans and high-energy braided streams is a response to abrupt climate change associated with aridity, hypoxia, acid rain, and mass wasting. Where neighbouring uplands were not uplifting or basins subsiding, alluvial fans are absent, but in these areas the climate change is evidenced by the disruption of pedogenesis

Prolonged Cycling Exercise Alters Neural Control Strategy, Irrespective of Carbohydrate Dose Ingested

The interactions between CHO dosage and neuromuscular regulation following fatiguing endurance exercise are not well understood. Fifteen well‐trained male cyclists completed 4 experimental trials of 120‐min submaximal cycling (95% lactate threshold) during which water (0 g CHO·h−1) or CHO beverages (20, 39, or 64 g CHO·h−1) were consumed every 15 minutes, at a rate of 1 L·h−1, followed by a work‐matched time trial ~30 minutes. Maximal voluntary contraction (MVC), M‐wave twitch potentiation and torque, motor unit recruitment and firing rate were recorded pre‐ and post‐cycling. Time trial performance improved following 39 and 64 versus 0 and 20 g CHO·h−1, with no effect of CHO dose on any pre‐ to post‐neuromuscular function measures. Pre‐ to post‐cycling exercise: (1) MVC, and M‐wave amplitude and duration declined by −21.5 Nm, and −4.9 mV and −7.1 ms, respectively; (2) peak evoked torque remained unchanged; (3) Firing rate of early‐ and mid‐recruited motor units increased by 0.93 pps and 0.74 pps, respectively, with no change in later‐recruited motor units. Thus, central drive to early‐ and mid‐recruited motor units increases as a result of endurance cycling, due to a likely fatigue compensatory mechanism. However, CHO availability does not appear to influence increased neuromuscular drive

Impact of Tumour Epithelial Subtype on Circulating MicroRNAs in Breast Cancer Patients

While a range of miRNAs have been shown to be dysregulated in the circulation of patients with breast cancer, little is known about the relationship between circulating levels and tumour characteristics. The aim of this study was to analyse alterations in circulating miRNA expression during tumour progression in a murine model of breast cancer, and to detemine the clinical relevance of identified miRNAs at both tissue and circulating level in patient samples. Athymic nude mice received a subcutaneous or mammary fat pad injection of MDA-MB-231 cells. Blood sampling was performed at weeks 1, 3 and 6 following tumour induction, and microRNA extracted. MicroRNA microArray analysis was performed comparing samples harvested at week 1 to those collected at week 6 from the same animals. Significantly altered miRNAs were validated across all murine samples by RQ-PCR (n = 45). Three miRNAs of interest were then quantified in the circulation(n = 166) and tissue (n = 100) of breast cancer patients and healthy control individuals. MicroArray-based analysis of murine blood samples revealed levels of 77 circulating microRNAs to be changed during disease progression, with 44 demonstrating changes .2-fold. Validation across all samples revealed miR-138 to be significantly elevated in the circulation of animals during disease development, with miR-191 and miR-106a levels significantly decreased. Analysis of patient tissue and blood samples revealed miR-138 to be significantly up-regulated in the circulation of patients with breast cancer, with no change observed in the tissue setting. While not significantly changed overall in breast cancer patients compared to controls, circulating miR-106a and miR-191 were significantly decreased in patients with basal breast cancer. In tissue, both miRNAs were significantly elevated in breast cancer compared to normal breast tissue. The data demonstrates an impact of tumour epithelial subtype on circulating levels of miRNAs, and highlights divergent miRNA profiles between tissue and blood samples from breast cancer patients