Water chemistry and endangered white-clawed crayfish: A literature review and field study of water chemistry association in Austropotamobius pallipes

Populations of the endangered white-clawed crayfish (Austropotamobius pallipes) have rapidly declined in distribution and density in recent decades as a result of invasive crayfish, disease and habitat degradation. The species is thought to be particularly sensitive to water chemistry, and has been proposed as a bio-indicator of water quality. Here we detail the results of a systematic review of the literature regarding the chemistry of waterbodies inhabited by white-clawed crayfish, along with a wide-scale field study of the chemistry of crayfish-inhabited waterbodies in the UK. We use these data to examine potentially significant variables influencing crayfish distribution. Several variables appear to have thresholds that affect crayfish distribution; crayfish presence was associated with high dissolved oxygen, low conductivity, ammonium, sodium, and phosphate, and to a lesser extent low sulphate, nitrate, and total suspended solids. Some variables (magnesium, potassium, sodium, sulphate, nitrate, and total suspended solids) may be tolerated at moderate to high concentrations in isolation (indicated by the presence of some populations in high levels of these variables), but suites of chemical conditions may act synergistically in situ and must be considered together. Recent efforts to conserve white-clawed crayfish have included relocations to Ark Sites; novel protected habitats with reduced risk of the introduction of disease, invasive crayfish and habitat degradation. We use our findings to propose the first detailed guidelines for common water chemistry variables of potential Ark Sites for the conservation of the species throughout its European range

Rooting out ultraweak photon emission a-mung bean sprouts

It is well known that life has evolved to use and generate light, for instance, photosynthesis, vision and bioluminescence. What is less well known is that during normal metabolism, it can generate 1–100 photons s−1 cm–2 known as ultra-weak photon emission (UPE), biophoton emission or biological autoluminescence. The highest generation of these metabolic photons seem to occur during oxidative stress due to the generation and decay of reactive oxygen species (ROS), and their interaction with other components of the cell. To study this further, we have configured a sensitive detection system to study photon emission in germinating mung beans. Here we investigated growing mung beans over 7 days at a constant temperature of 21 ± 1 °C in a light tight box, using dual top and bottom opposing photomultiplier tubes. Over this time period we showed that in total, mung beans grown from seeds generated an average of 5 ± 1 counts s−1 above background. As the new bean stems grew, they showed a gradual linear increase in emission of up to 30 ± 1 counts s−1, in agreement with previous literature. In addition to this “steady-state” emission we also observe delayed luminescence and drought-stress response emission previously observed in other species. Finally, we also observe episodic increased emission events of between 2 and 15 counts s−1 for durations of around 3 h detected underneath the sample, and assign these to the growing of secondary roots. We then induce secondary root formation using aqueous solutions of growth hormones hydrogen peroxide (H2O2, 167 µM) or 3-indole acetic acid (IAA, 0.5 µM) for watering. Both hormones show prolonged increase in emission above steady-state, over days 3–5 with at least 3 times the number of secondary roots formed compared with water alone. We also observed a significant peak increase in photon emission (474 and 1738 cps vs. 28 and 55 cps for water alone) for the H2O2 which we attribute to direct ROS reaction emission as confirmed by measurement on dead plants. Altogether we have expanded upon and demonstrated an instrument and biological system for reliably producing and measuring intrinsic metabolic photons, first observed 100 years ago by Alexander Gurwitsch

Comparison of organic and conventional farming systems with particular reference to soil fertility

Organic farmers in Europe and North America often achieve comparable returns to conventional farmers. In contrast with soils of Europe and North America, to those in southern Australia are often highly weathered and have very low nutrient reserves. The present study was conducted to quantify wheat production levels in organic and conventionally grown wheat fields in south-west Australia, and to relate these to soil nutrient status

Groundwater resilience Nepal: preliminary findings from a case study in the Middle Hills

Groundwater resources in the Middle Hills of Nepal perform a major role in supplying domestic and irrigation water and in regulating river flows. However, there has been little systematic study of groundwater within the region, making it difficult to evaluate how water supplies and river flows may change in response to climatic and anthropogenic change. To begin to build an evidence base, two catchments in the Middle Hills were investigated. The aim of the study was to characterise the hydrogeology of the catchments, assess water supplies and water usage and evaluate how resilient groundwater may be to change. Two contrasting sub-catchments within the Kali Gandaki River catchment were chosen: Ramche Village Development Committee (VDC), at an elevation of 2000 – 3000 m, with subsistence terraced farming and highly forested slopes, and Madanpokhara VDC which is largely below 1000 m, with expanding commercial agriculture. Groundwater sampling was undertaken during the post-monsoon season 2013 and pre-monsoon season 2014. Springs, tube wells and rivers across the two catchments were investigated using a combination of surveys, flow measurements, and sampling for inorganic chemistry, stable isotopes, groundwater residence time indicators (CFC and SF6) and noble gases. In addition, 12 months of weekly hydrological monitoring and monthly water usage surveys were undertaken at several sites. There is a heavy reliance on springs for water supply in Ramche. The springs are typically perennial but with significantly reduced flows during the winter and pre-monsoon season. The springs have bicarbonate groundwater chemistry and generally low overall mineralisation. Springs issuing from the higher slopes are reliant on seasonal monsoon rainfall and snow to sustain higher flows, but baseflows are sustained by groundwater storage within the weathered aquifer and will therefore have some inter-annual storage. Discrete springs issuing from lower slopes are most likely to be fed from groundwater storage within the fractured aquifer network. Groundwater residence time indicators (CFC and SF6) suggest a mean residence time of 10-20 years for pre-monsoon groundwater, implying inter-annual storage and therefore some built in resilience. However the general low storage of the groundwater environment suggests that none of the springs would be resilient to a long term reduction in precipitation. In the lower catchment of Madanpokhara where floodplain and outwash deposits are present, many hand-drilled shallow tubewells have been installed in the last 5-10 years, decreasing the reliance on springs. The development of groundwater resources has resulted in a thriving agricultural co-operative, inward migration and a growing population. These shallow tubewells have increased the resilience of the water supplies to change but are potentially vulnerable to over-exploitation as a result of the rapid increase in abstraction. Groundwater sampled in tubewells along the margin of the floodplain is modern (~20 yrs Mean Residence Time (MRT)) with bicarbonate groundwater chemistry and no significant water quality concerns. Groundwater sampled from tubewells towards the centre of the floodplain appears to be older (~50 yrs MRT) with elevated concentrations of iron, manganese, zinc and arsenic detected at some sites. With a growing recognition of the importance of groundwater storage in the Middle Hills there is significant potential to further advance the characterisation of groundwater systems and investigate the resilience of groundwater supplies to change. Systematic monitoring of groundwater, as springs flows, groundwater levels and chemistry would give a much better understanding of emerging trends. Likewise, monitoring current yields of springs and comparing to historic values at installation may allow some conclusions to be drawn about the trajectory of springflow. There are several groundwater-related initiatives underway within organisations in Nepal; the lessons learned from this current research, the methodologies used and the preliminary findings will be of value to these

Production of cold bromine atoms at zero mean velocity by photodissociation

The production of a translationally cold (T < 1 K) sample of bromine atoms with estimated densities of up to 108 cm−3 using photodissociation is presented. A molecular beam of Br2 seeded in Kr is photodissociated into Br + Br* fragments, and the velocity distribution of the atomic fragments is determined using (2 + 1) REMPI and velocity map ion imaging. By recording images with varying delay times between the dissociation and probe lasers, we investigate the length of time after dissociation for which atoms remain in the laser focus, and determine the velocity spread of those atoms. By careful selection of the photolysis energy, it is found that a fraction of the atoms can be detected for delay times in excess of 100 μs. These are atoms for which the fragment recoil velocity vector is directly opposed and equal in magnitude to the parent beam velocity leading to a resultant lab frame velocity of approximately zero. The FWHM velocity spreads of detected atoms along the beam axis after 100 μs are less than 5 ms−1, corresponding to temperatures in the milliKelvin range, opening the possibility that this technique could be utilized as a slow Br atom source

Particle Acceleration at Relativistic Shocks

I review the current status of Fermi acceleration theory at relativistic shocks. I first discuss the relativistic shock jump conditions, then describe the non-relativistic Fermi mechanism and the differences introduced by relativistic flows. I present numerical calculations of the accelerated particle spectrum, and examine the maximum energy attainable by this process. I briefly consider the minimum energy for Fermi acceleration, and a possible electron pre-acceleration mechanism.Comment: 17 pages, 4 figures. To appear in "Relativistic Flows in Astrophysics", A.W. Guthmann, M. Georganopoulos, A. Marcowith and K. Manolokou, eds., Lecture Notes in Pysics, Springer Verla

Polarization Correlations of 1S0 Proton Pairs as Tests of Bell and Wigner Inequalities

In an experiment designed to overcome the loophole of observer dependent reality and satisfying the counterfactuality condition, we measured polarization correlations of 1S0 proton pairs produced in 12C(d,2He) and 1H(d,He) reactions in one setting. The results of these measurements are used to test the Bell and Wigner inequalties against the predictions of quantum mechanics.Comment: 8 pages, 4 figure

Efficacy of increased resistant starch consumption in human type 2 diabetes

Resistant starch (RS) has been shown to beneficially affect insulin sensitivity in healthy individuals and those with metabolic syndrome, but its effects on human type 2 diabetes (T2DM) are unknown. This study aimed to determine the effects of increased RS consumption on insulin sensitivity and glucose control and changes in postprandial metabolites and body fat in T2DM. Seventeen individuals with well-controlled T2DM (HbA1c 46.6±2 mmol/mol) consumed, in a random order, either 40 g of type 2 RS (HAM-RS2) or a placebo, daily for 12 weeks with a 12-week washout period in between. At the end of each intervention period, participants attended for three metabolic investigations: a two-step euglycemic–hyperinsulinemic clamp combined with an infusion of [6,6-2H2] glucose, a meal tolerance test (MTT) with arterio-venous sampling across the forearm, and whole-body imaging. HAM-RS2 resulted in significantly lower postprandial glucose concentrations (P=0.045) and a trend for greater glucose uptake across the forearm muscle (P=0.077); however, there was no effect of HAM-RS2 on hepatic or peripheral insulin sensitivity, or on HbA1c. Fasting non-esterified fatty acid (NEFA) concentrations were significantly lower (P=0.004) and NEFA suppression was greater during the clamp with HAM-RS2 (P=0.001). Fasting triglyceride (TG) concentrations and soleus intramuscular TG concentrations were significantly higher following the consumption of HAM-RS2 (P=0.039 and P=0.027 respectively). Although fasting GLP1 concentrations were significantly lower following HAM-RS2 consumption (P=0.049), postprandial GLP1 excursions during the MTT were significantly greater (P=0.009). HAM-RS2 did not improve tissue insulin sensitivity in well-controlled T2DM, but demonstrated beneficial effects on meal handling, possibly due to higher postprandial GLP1

Trustworthiness perception is mandatory : Task instructions do not modulate fast periodic visual stimulation trustworthiness responses

Acknowledgments The authors thank Bruno Rossion, Joan Liu-Shuang, Talia Retter, and Amy Dawel for their advice and helpful discussions, and Alex Todorov for providing the face stimuli. Supported by an RTP scholarship from the University of Western Australia to DS, an Australian Research Council (ARC) Discovery Early Career Research Award to CS (DE190101043), and ARC Discovery Projects to CS and RP (DP170104602) and RP (DP140101743).Peer reviewedPublisher PD

Magnetic fields in cosmic particle acceleration sources

We review here some magnetic phenomena in astrophysical particle accelerators associated with collisionless shocks in supernova remnants, radio galaxies and clusters of galaxies. A specific feature is that the accelerated particles can play an important role in magnetic field evolution in the objects. We discuss a number of CR-driven, magnetic field amplification processes that are likely to operate when diffusive shock acceleration (DSA) becomes efficient and nonlinear. The turbulent magnetic fields produced by these processes determine the maximum energies of accelerated particles and result in specific features in the observed photon radiation of the sources. Equally important, magnetic field amplification by the CR currents and pressure anisotropies may affect the shocked gas temperatures and compression, both in the shock precursor and in the downstream flow, if the shock is an efficient CR accelerator. Strong fluctuations of the magnetic field on scales above the radiation formation length in the shock vicinity result in intermittent structures observable in synchrotron emission images. Resonant and non-resonant CR streaming instabilities in the shock precursor can generate mesoscale magnetic fields with scale-sizes comparable to supernova remnants and even superbubbles. This opens the possibility that magnetic fields in the earliest galaxies were produced by the first generation Population III supernova remnants and by clustered supernovae in star forming regions.Comment: 30 pages, Space Science Review