The application of S isotopes and S/Se ratios in determining ore-forming processes of magmatic Ni–Cu–PGE sulfide deposits: a cautionary case study from the northern Bushveld Complex

The application of S/Se ratios and S isotopes in the study of magmatic Ni–Cu–PGE sulfide deposits has long been used to trace the source of S and to constrain the role of crustal contamination in triggering sulfide saturation. However, both S/Se ratios and S isotopes are subject to syn- and post-magmatic processes that may alter their initial signatures. We present in situ mineral δ34S signatures and S/Se ratios combined with bulk S/Se ratios to investigate and assess their utility in constraining ore-forming processes and the source of S within magmatic sulfide deposits. Magmatic Ni–Cu–PGE sulfide mineralization in the Grasvally Norite–Pyroxenite–Anorthosite (GNPA) member, northern Bushveld Complex was used as a case study based on well-defined constraints of sulfide paragenesis and local S isotope signatures. A crustal δ34S component is evident in the most primary sulfide assemblage regardless of footwall lithology, and is inferred that the parental magma(s) of the GNPA member was crustally contaminated and sulfide saturated at the time of emplacement. However, S/Se ratios of both the primary and in particular secondary sulfide assemblages record values within or below the mantle range, rather than high crustal S/Se ratios. In addition, there is a wide range of S/Se ratio for each sulfide mineral within individual assemblages that is not necessarily consistent with the bulk ratio. The initial crustal S/Se ratio is interpreted to have been significantly modified by syn-magmatic lowering of S/Se ratio by sulfide dissolution, and post-magmatic lowering of the S/Se ratio from hydrothermal S-loss, which also increases the PGE tenor of the sulfides. Trace element signatures and variations in Th/Yb and Nb/Th ratios support both an early pre-emplacement contamination event as seen by the S isotopes and S/Se ratios, but also a second contamination event resulting from the interaction of the GNPA magma with the local footwall country rocks at the time of emplacement; though this did not add any additional S. We are able to present an integrated emplacement and contamination model for the northern limb of the Bushveld Complex. Although the multitude of processes that affect variations in the δ34S signature and in particular S/Se ratio may be problematic in interpreting ore genesis, they can reveal a wealth of additional detail on a number of processes involved in the genetic history of a Ni–Cu–PGE deposit in addition to crustal contamination. However, a prerequisite for being able to do this is to utilize other independent petrological and mineralogical techniques that provide constraints on both the timing and effect of various ore-forming and modifying processes. Utilizing both bulk and in situ methods in concert to determine the S/Se ratio allows for the assessment of multiple sulfide populations, the partitioning behaviour of Se during sulfide liquid fractionation and also the effects of low temperature fluid alteration. In comparison, S isotopes are relatively more robust and represent a more reliable indicator of the role of crustal S contamination. The addition of trace element data to the above makes for an incredibly powerful approach in assessing the role of crustal contamination in magmatic sulfide systems

Foot and Mouth Epidemic Reduces Cases of Human Cryptosporidiosis in Scotland.

In Scotland, rates of cryptosporidiosis infection in humans peak during the spring, a peak that is coincident with the peak in rates of infection in farm animals (during lambing and calving time). Here we show that, during the outbreak of foot and mouth disease (FMD) in 2001, there was a significant reduction in human cases of cryptosporidiosis infection in southern Scotland, where FMD was present, whereas, in the rest of Scotland, there was a reduction in cases that was not significant. We associate the reduction in human cases of cryptosporidiosis infection with the reduction in the number of young farm animals, together with restrictions on movement of both farm animals and humans, during the outbreak of FMD in 2001. We further show that, during 2002, there was recovery in the rate of cryptosporidiosis infection in humans throughout Scotland, particularly in the FMD-infected area, but that rates of infection remained lower, though not significantly, than pre-2001 levels

Insulin signaling as a therapeutic mechanism of lithium in bipolar disorder

In this paper, we propose that lithium may exert its therapeutic effect in bipolar disorder by acting on insulin signaling pathways. Specifically, we assess the importance of the phosphatidylinositol 3-kinase/Protein Kinase B (PI3K/Akt) insulin signaling pathway and we assess how the action of lithium on both glycogen synthase kinase-3 (GSK3) and the phosphatidylinositol cycle may lead to mood stabilization mediated by PI3K/Akt insulin signaling. We also highlight evidence that several other actions of lithium (including effects on Akt, Protein kinase C (PKC), and sodium myo-inositol transporters) are putative mediators of insulin signaling. This novel mode of action of lithium is consistent with an emerging consensus that energy dysregulation represents a core deficit in bipolar disorder. It may also provide context for the significant co-morbidity between bipolar disorder, type 2 diabetes, and other forms of metabolic illness characterized by impaired glucose metabolism. It is suggested that developments in assessing neuronal insulin signaling using extracellular vesicles would allow for this hypothesis to be tested in bipolar disorder patients

CumbraeCraft:a virtual environment for teaching cultural heritage to primary schoolchildren

Game-based learning is a research area that has grown within the past two decades, with evidence of tailoring commercial-off-the-shelf gaming, developing bespoke educational games, and using gamification-based learning tools in a variety of educational settings. However, the Covid-19 pandemic has accelerated the need to focus on virtual learning experiences that are engaging and motivating for schoolchildren to participate in as they face learning from home. Games are one such method of virtual learning experiences that aim to provide a stimulating experience for young people to continue their compulsory education. This paper introduces a project developed between Millport Conservation Area Regeneration Scheme (CARS) and a small team of game development students and academics from Abertay University. The purpose of the project was to develop a Minecraft Education world that could be used by teachers to engage primary schoolchildren in the history and heritage of the Isle of Cumbrae, an island in North Ayrshire, western Scotland. The project also set out to achieve aims of promoting local heritage and heritage tourism, enhancing national educational standards, serving as an electronic record of local heritage, and introducing potential career options in gaming to young people. The result - CumbraeCraft - is a suite of eight lessons that support teachers to use the game within the classroom as a way of teaching young people about local heritage and culture. The world focused on recreating locations and events from the Isle of Cumbrae to present interesting facts and knowledge to pupils in an interactive and enjoyable manner, focusing on interactions of exploration and discovery, narrative and communication, fellowship and teamwork, expression and creativity, and challenge-based learning. The aim of this paper is to present a case study on the design and development of CumbraeCraft as an educational environment to teach the heritage and history of island communities in western Scotland. Additionally, the paper spotlights a gap for games to be used to teach young people about local heritage and the historical significance of their communities and culture, with a particular emphasis on Scottish culture, language, and tradition.</p

A grounded theory of inspirational coach leadership

The purpose of this study was to develop a grounded theory of the process of inspirational coach leadership in sport. A Straussian grounded theory methodology was used. Semi‐structured interviews and focus groups were conducted with athletes (n = 22) and coaches (n = 15). Data were analyzed through a process of open and axial coding, and theoretical integration. Through the process of analysis, data were broken down into smaller units (concepts), relationships between concepts were identified, and a substantive grounded theory was developed. The grounded theory of inspirational coach leadership was built around the core category of “athlete(s) inspired through changed awareness of their capabilities.” The core category was underpinned by three categories: (a) establishment of mutual trust and respect with athletes, whereby coaches need to establish trust with athletes in order to inspire athletes; (b) conditions under which inspiration has the potential to occur, which highlighted that athletes are inspired in situations where they are vulnerable or ignorant regarding their potential; and (c) coach acts to change athlete's awareness of their capabilities, which denotes the specific behaviors coaches should display to inspire athletes in such conditions. The theory also highlights that a range of contextual factors relating to the coach, athletes, and performance‐environment interact to impact upon the process. The theory predicts that consistency between coach behavior and the conditions in which inspiration can occur will lead to athlete inspiration, but only if the coach has established a foundation of trust and respect with the athlete

NuSTAR hard X-ray observation of a sub-A class solar flare

We report a NuSTAR observation of a solar microflare, SOL2015-09-01T04. Although it was too faint to be observed by the GOES X-ray Sensor, we estimate the event to be an A0.1 class flare in brightness. This microflare, with only 5 counts per second per detector observed by RHESSI, is fainter than any hard X-ray (HXR) flare in the existing literature. The microflare occurred during a solar pointing by the highly sensitive NuSTAR astrophysical observatory, which used its direct focusing optics to produce detailed HXR microflare spectra and images. The microflare exhibits HXR properties commonly observed in larger flares, including a fast rise and more gradual decay, earlier peak time with higher energy, spatial dimensions similar to the RHESSI microflares, and a high-energy excess beyond an isothermal spectral component during the impulsive phase. The microflare is small in emission measure, temperature, and energy, though not in physical size; observations are consistent with an origin via the interaction of at least two magnetic loops. We estimate the increase in thermal energy at the time of the microflare to be 2.4x10^27 ergs. The observation suggests that flares do indeed scale down to extremely small energies and retain what we customarily think of as "flarelike" properties.Comment: Status: Accepted by the Astrophysical Journal, 2017 July 1

Habitat Selection of Invasive Sika Deer Cervus nippon Living in a UK Lowland Heathland-Woodland-Grassland Mosaic: Implications for Habitat Conservation Management.

Understanding the factors determining the choice and use of habitats by invasive species is key to the conservation management of habitats and may also enable species to be harnessed as conservation tools. Here we explore the habitat use of an invasive population of sika deer, Cervus nippon on internationally important heathland in a landscape of heathland, grassland and woodland in southern UK. We used radio telemetry to test two hypotheses 1) grasses form a major part of the diet of non-native UK sika deer throughout the year 2) deer select grassland habitats above other habitats available. Results showed that although grasses form a major part of their diet, the strongest habitat selection was for heathland, the habitat that offered the least nutrient reward but which offered a source of roughage in the diet and some harbourage from human disturbance. This has implications for the conservation management of heathlands used by sika deer as it strongly indicates that heathland is a vulnerable habitat due to being favoured by sika deer but that its vulnerability can be reduced by coupling population control with targeted habitat management action such as increased disturbance or the removal of harbourage

Microflare Heating of a Solar Active Region Observed with NuSTAR, Hinode/XRT, and SDO/AIA

NuSTAR is a highly sensitive focusing hard X-ray (HXR) telescope and has observed several small microflares in its initial solar pointings. In this paper, we present the first joint observation of a microflare with NuSTAR and Hinode/XRT on 2015 April 29 at ~11:29 UT. This microflare shows heating of material to several million Kelvin, observed in Soft X-rays (SXRs) with Hinode/XRT, and was faintly visible in Extreme Ultraviolet (EUV) with SDO/AIA. For three of the four NuSTAR observations of this region (pre-, decay, and post phases) the spectrum is well fitted by a single thermal model of 3.2-3.5 MK, but the spectrum during the impulsive phase shows additional emission up to 10 MK, emission equivalent to A0.1 GOES class. We recover the differential emission measure (DEM) using SDO/AIA, Hinode/XRT, and NuSTAR, giving unprecedented coverage in temperature. We find the pre-flare DEM peaks at ~3 MK and falls off sharply by 5 MK; but during the microflare's impulsive phase the emission above 3 MK is brighter and extends to 10 MK, giving a heating rate of about $2.5 \times 10^{25}$ erg s$^{-1}$. As the NuSTAR spectrum is purely thermal we determined upper-limits on the possible non-thermal bremsstrahlung emission. We find that for the accelerated electrons to be the source of the heating requires a power-law spectrum of $\delta \ge 7$ with a low energy cut-off $E_{c} \lesssim 7$ keV. In summary, this first NuSTAR microflare strongly resembles much more powerful flares.Comment: Accepted for publication in ApJ. 14 pages with 12 figures and 1 tabl

On the Mutual Information Distribution of OFDM-Based Spatial Multiplexing: Exact Variance and Outage Approximation

This paper considers the distribution of the mutual information of frequency-selective spatially-uncorrelated Rayleigh fading MIMO channels. Results are presented for OFDM-based spatial multiplexing. New exact closed-form expressions are derived for the variance of the mutual information. In contrast to previous results, our new expressions apply for systems with both arbitrary numbers of antennas and arbitrary-length channels. Simplified expressions are also presented for high and low SNR regimes. The analytical variance results are used to provide accurate analytical approximations for the distribution of the mutual information and the outage capacity.Comment: 18 pages, 10 figures, accepted for publication in IEEE Transactions on Information Theor