Mass gatherings (MG) present a number of challenges to public health authorities and governments across the world with sporting events, tournaments, music festivals, religious gatherings and all other MG having historically posed a risk to the spread and amplification of a range of infectious diseases. Transmission of gastrointestinal, respiratory, waterborne and sexually transmitted infectious diseases pose a particular risk: all have been linked to MG events [1–4]. Infection risk often depends on the nature of the mass gathering, and on the profile and behaviour of its participants. The interaction between environmental, psychological, biological and social factors plays a vital part. The risk of outbreaks particularly as a result of respiratory transmission remains high at MG, with the majority of outbreaks over the last two decades resulting from a variety of respiratory and vaccine preventable pathogens [5–7]. Concerns about the spread of infectious diseases at MG are often focussed on crowding, lack of sanitation and the mixing of population groups from different places. Sporting events, which have in recent decades become more complex and international in nature, pose a challenge to the control of communicable disease transmission [8]. Despite this, large scale outbreaks at sporting events have been rare in recent decades, particularly since the rise of more robust public health planning, prevention, risk assessment and improved health infrastructures in host countries [9].

Ancient metamorphic processes are recorded by the formation of metallic-Pb nanospheres in zircon, a product of internal Pb mobilisation and thermally driven concentration. Here, metallic-Pb nanospheres formed within an ore deposit are characterised for the first time using high-angle annular dark field scanning transmission electron microscopy and energy-dispersive X-ray spectroscopy element-distribution mapping. Exceptional examples from the migmatite-hosted Archean–Paleoproterozoic Challenger Au deposit (Central Gawler Craton, South Australia) support widespread metallic-Pb nanosphere formation in zircon from rocks experiencing granulite-facies metamorphism. We also report new trace-element associations found with metallic-Pb nanospheres and a new mode of occurrence, in which Sc ‘haloes’ form adjacent to metallic-Pb nanospheres within the crystalline zircon lattice. This differs to previously characterised examples of metallic-Pb nanospheres associated with amorphous Si-rich glasses and unidentified Al–Ti, or Fe-bearing phases. Multiple modes of metallic-Pb nanosphere occurrences and trace-element associations suggests multiple modes of formation, probably dependant on zircon composition and metamorphic conditions. Identification of metallic-Pb nanospheres in a growing range of geological settings further highlights the mobility of Pb in zircon and the importance of detailed, nanoscale mineral characterisation, in order to constrain accurate geochronological histories for rocks within high-temperature geological environments.

Gravitational waves from coalescing neutron stars encode information about nuclear matter at extreme densities, inaccessible by laboratory experiments. The late inspiral is influenced by the presence of tides, which depend on the neutron star equation of state. Neutron star mergers are expected to often produce rapidly rotating remnant neutron stars that emit gravitational waves. These will provide clues to the extremely hot post-merger environment. This signature of nuclear matter in gravitational waves contains most information in the 2–4 kHz frequency band, which is outside of the most sensitive band of current detectors. We present the design concept and science case for a Neutron Star Extreme Matter Observatory (NEMO): a gravitational-wave interferometer optimised to study nuclear physics with merging neutron stars. The concept uses high-circulating laser power, quantum squeezing, and a detector topology specifically designed to achieve the high-frequency sensitivity necessary to probe nuclear matter using gravitational waves. Above 1 kHz, the proposed strain sensitivity is comparable to full third-generation detectors at a fraction of the cost. Such sensitivity changes expected event rates for detection of post-merger remnants from approximately one per few decades with two A+ detectors to a few per year and potentially allow for the first gravitational-wave observations of supernovae, isolated neutron stars, and other exotica.

Noncommunicable diseases (NCDs) are a growing challenge in the Republic of Moldova. A previously reported pilot cluster randomized controlled trial aimed to determine the feasibility of implementing and evaluating essential interventions for NCDs (e.g. cardiovascular risk scoring, hypertension management, statin treatment, etc.) in primary health care in the Republic of Moldova, with a view toward national scale up. One-year follow-up data (previously published) demonstrated modest improvements in NCD risk factor identification and management could be achieved. Herein, we report the second-year follow-up data and conclude that sustainable improvements in NCD risk factor control (e.g. hypertension control) can be achieved in primary health care in low resource settings by adapting existing resources (e.g. WHO PEN) and conducting focused clinical training and support. If scaled to a national level, these improvements in risk factor control could significantly translate to reductions in premature mortality from NCDs.

Preferential removal of W relative to other trace elements from zoned, W–Sn–U–Pb-bearing hematite coupled with disturbance of U–Pb isotope systematics is attributed to pseudomorphic replacement via coupled dissolution reprecipitation reaction (CDRR). This hematite has been studied down to the nanoscale to understand the mechanisms leading to compositional and U/Pb isotope heterogeneity at the grain scale. High-Angle Annular Dark Field Scanning Transmission Electron Microscopy (HAADF STEM) imaging of foils extracted in situ from three locations across the W-rich to W-depleted domains show lattice-scale defects and crystal structure modifications adjacent to twin planes. Secondary sets of twins and associated splays are common, but wider (up to ~100 nm) inclusion trails occur only at the boundary between the W-rich and W-depleted domains. STEM energy-dispersive X-ray mapping reveals W- and Pb-enrichment along 2–3 nm-wide features defining the twin planes; W-bearing nanoparticles occur along the splays. Tungsten and Pb are both present, albeit at low concentrations, within Na–K–Cl-bearing inclusions along the trails. HAADF STEM imaging of hematite reveals modifications relative to ideal crystal structure. A two-fold hematite superstructure (a = b = c = 10.85 Å; α = β = γ = 55.28°) involving oxygen vacancies was constructed and assessed by STEM simulations with a good match to data. This model can account for significant W release during interaction with fluids percolating through twin planes and secondary structures as CDRR progresses from the zoned domain, otherwise apparently undisturbed at the micrometre scale. Lead remobilisation is confirmed here at the nanoscale and is responsible for a disturbance of U/Pb ratios in hematite affected by CDRR. Twin planes can provide pathways for fluid percolation and metal entrapment during post-crystallisation overprinting. The presence of complex twinning can therefore predict potential disturbances of isotope systems in hematite that will affect its performance as a robust geochronometer.

In the medical field, the monitoring of the neurotransmitters in depressive patients represents a major demand focusing of course on the health state of the patients, with social and economical effects. The efficient control of the health state cannot be realized with the help of the traditional chemical and/or biochemical methods precise and selective, but expensive and laborious. Traditional methods for identification and detection and of neurotransmitters lack the speed and sensitivity to be of real usage since that they are not real time or even typically completed in a single day. One possible solution is represented by the use of the chemically modified electrodes. The compatibility with micro-fabrication technology and the low cost of these devices make them promising tool for the rapid and inexpensive detection on-line of neurotransmitters.

In the study of phthalocyanine (PhC) chemistry, an area of particular interest in recent years has been the formation and characterization of polymeric compounds in various forms and the use of these compounds to carry out well known PhC applications involving catalysis, analysis, etc. Metallophthalocyanine (MPhC) complexes catalyze the detection of neurotransmitters. The catalytic activity of ferophthalocyanine towards different neurotransmitters was compared with those of Co and NiMPhC complexes. The chemically modified electrodes have been tested for the capacity to electrochemically detect dopamine, epinephrine and serotonin (5-HT). Interference of ascorbic acid in the CP modified electrodes response was also investigated. Applications on real samples will be considered.

In this paper we introduce and study the conjugacy ratio of a finitely generated group, which is the limit at infinity of the quotient of the conjugacy and standard growth functions. We conjecture that the conjugacy ratio is 0 for all groups except the virtually abelian ones, and confirm this conjecture for certain residually finite groups of subexponential growth, hyperbolic groups, right-angled Artin groups and the lamplighter group.

Trace mineral assemblages in the bornite- and chalcopyrite-rich Cu-Fe zone of the Ocna de Fier-Dognecea skarn deposits, Banat, SW Romania provide additional constraints on the genesis of this classic zoned skarn system. Observed assemblages substantiate a model, in which the Cu-Fe zone forms the proximal fluid-plume root of the system. Observed trace mineral assemblages in the magnesian forsterite-bearing skarns crystallized at ~650°C in a volatile-rich environment, evidenced by widespread phlogopite, ludwigite, valleriite and apatite. The entire assemblage thus belongs to the initial stage of skarn formation. Prolonged cooling led to sequential exsolution of trace mineral phases from bornite and chalcopyrite during the retrograde stage, although still at temperatures in excess of 500°C. Bornite is typified by the abundance of exsolved phases along cleavage planes and along crystal margins, notably chalcopyrite and pyrrhotite, but also cobalt pentlandite, carrollite, wittichenite, galena, mawsonite, silver and electrum. Chalcopyrite hosts cobalt pentlandite, carrollite, wittichenite, galena and a sequence of Se- and Te-bearing minerals (kawazulite, bohdanowiczite, hessite, volynskite), along, although not restricted to, grain margins. The assemblage bornite-chalcopyrite-magnetite, with the trace phases, cobalt pentlandite, carrollite, wittichenite and various Se- and Te-bearing minerals represents a characteristic assemblage common to a disparate range of deposits formed at temperatures in excess of 500°C in the presence of volatiles and typified by relatively low fS2 fluids.

Coherent intergrowths, at the lattice scale, between cuprobismutite (N = 2) and structurally related paděraite along both major axes (15 Å and 17 Å repeats) of the two minerals are reported within skarn from Ocna de Fier, Romania. The structural subunit, DTD, 3 layers of paděraite, is involved at interfaces of the two minerals along the 15 Å repeat, as well as in transposition of 1 paděraite unit to 2 cuprobismutite units along the 17 Å repeat in slip defects. Lattice images obtained by HRTEM across intervals of 200–400 nm show short- to long-range stacking sequences of cuprobismutite and padeÏ raite ribbons. Such nanoscale slabs mimic mm-scale intergrowths observed in back-scattered electron images at three orders of magnitude greater. These slabs are compositionally equivalent to intermediaries in the cuprobismutite-paděraite range encountered during microanalysis. Hodrushite (N = 1.5) is identified in the mm-scale intergrowths, but its absence in the lattice images indicates that, in this case, formation of polysomes between structurally related phases is favoured instead of stacking disorder among cuprobismutite homologues. The tendency for short-range ordering and semi-periodic occurrence of polysomes suggests they are the result of an oscillatory chemical signal with periodicity varying from one to three repeats of 15 Å, rather than simple ‘accidents’ or irregular structural defects. Lead distribution along the polysomes is modelled as an output signal modulated by the periodicity of stacking sequences, with Pb carried within the D units of paděraite. This type of modulator acts as a patterning operator activated by chemical waves with amplitudes that encompass the chemical difference between the minerals. Conversion of the paděraite structural subunit DTD to the C unit of cuprobismutite, conserving interval width, emphasizes that polysomatic modularity also assists interference of chemical signals with opposite amplitudes. Observed coarsening of lattice-scale intergrowths up to the mm-scale implies coupling between diffusion-controlled structural modulation, and rhythmic precipitation at the skarn front during crystallization.

Intermediate levels of the Larga-Fatţa Báii field, Metaliferi Mts., Romania, are host to epithermal vein mineralization, small skarn-like bodies and ‘geode’-like replacement ores, that together form a complex hydrothermal system rooted in the subjacent andesite stock. Silver-Pb-Bi sulphosalts, some with Sb and/or Se, are intimately associated with hessite and a range of Bi-tellurides with Bi/(Te+S+Se) ≤1 (tetradymite, tellurobismuthite, tsumoite, Pb-free rucklidgeite) within all these ore types. Lillianite homologues, both ordered 4L and 7L derivatives (lillianite, gustavite), and disordered varieties are the most abundant sulphosalts, with subordinate bismuthinite derivatives (aikinite, krupkaite, bismuthinite). An exceptionally Ag-rich lillianite homologue, intimately intergrown with tetradymite and hessite, is identified as treasureite on the basis of chemical composition. Porphyry-style mineralization from 600 m beneath the studied level contains rucklidgeite as the single stable Bi-telluride. The trace mineralogy of the system is suggestive of a hydrothermal system strongly zoned with respect to fTe2 and, to a lesser extent, also fS2. Mineralogical and textural evidence suggests that initial crystallization took place at temperatures in excess of 400°C. The association of gold with Bi-minerals is linked to the role of Bimelt as a scavenger for gold, and deposition within ‘droplets’ simultaneous with the formation of arsenopyrite from löllingite + pyrrhotite. Both Bi-tellurosulphides and sulphosalts are commonly non-stoichiometric, a fact that can be correlated with order-disorder in both series. When widely distributed, as in the Larga system, trace amounts of Bi-minerals (sulphosalts, tellurides/tellurosulphides) have considerable, untapped potential as tracers of the physical-chemical character of an evolving hydrothermal system.