Models of cation exchange mechanisms and driving forces have proven effective predictors of clay behavior and chemistry, but are largely theoretical, particularly in complex systems involving high ionic strength brines or systems where hydration is controlled by relative humidity. In arid and cold environments, such as Mars, cyclical relative humidity variations may play a role in chemical alteration, particularly if clay minerals such as smectite are in the presence of salts. This study examines the effects of relative humidity on smectite-salt mixtures using environmental scanning electron microscopy (ESEM) to observe the physiochemical effects of salt deliquescence and desiccation on smectite textures and elemental distributions. Results demonstrate that even reaction periods as short as a few minutes allow ample time for relative humidity to affect the smectite-salt mixtures. In addition to smectite swelling and salt deliquescence, we also observed rapid changes in element distributions within the smectite and new crystal growth in the presence of high relative humidity. Even in the absence of bulk liquid water, exchangeable cations migrated out of the smectite and formed new crystals at the smectite-salt interface. The observed microscopic changes in elemental distributions indicate that the migration of cations driven by cation exchange led to secondary mineral precipitation, likely a CaSO4 mineral, within a sub-micrometer-thick layer of water on the smectite grains. The results of this study demonstrate that during periods of elevated relative humidity, active smectite mineral alteration and secondary mineral precipitation may be possible on present-day Mars where salts and smectites are in direct physical contact.

The relationship between frailty and glycemic control in older adults with diabetes remains uncertain, mainly due to the fact that previous studies have not accounted for measures of body composition. In older adults with diabetes, we examined the association between three types of frailty measures and glycemic control, while accounting for fat-free mass (FFM) and waist circumference (WC). Eighty older adults (age ≥65, 27 women and 53 men, mean age 80.5 ± 0.6 years) had gait speed, Cardiovascular Health Study Index (CHSI), Rockwood Clinical Frailty Scale (RCFS), and glycosylated hemoglobin (HgA1C) measured. HgA1C showed a negative association only with CHSI (standardized β = −0.255 ± 0.120, p = 0.038), but no association with gait speed or the RCFS. Even after accounting for FFM and WC, we demonstrated a negative association between glycated hemoglobin and increasing frailty in older adults with diabetes.

The coefficient of friction of clay minerals at the micro-scale has generally not been studied due to difficulties in obtaining measurements in a bulk-soil volume undergoing shear at such small scales. Information on friction at the micro-scale may provide insight into grain-scale processes that operate in bulk samples or in natural faults. The objective of this study was to develop a method to measure the microscale friction coefficient of smectites. The experiments described show that the axial atomic force microscopy method can be adapted to easily obtain accurate coefficient of friction (μ) measurements for smectites from force curves involving colloidal probes. The method allows for the measurements to be performed over spatial scales of a few μm, can be carried out under dry conditions or a wide range of aqueous solutions, and requires no calibration beyond making a few microscopic measurements of the probe. This method provides measurements of micro-scale normal and shear forces between minerals, which can be used for a variety of applications such as the study of shear deformation, consolidation, and fault dynamics. Control tests of silica on mica (μ = 0.29±0.02) agree with literature values where limits indicate one standard deviation. Coefficient of friction values for wet and dry Na-montmorillonite were determined to be 0.20±0.03 and 0.72±0.03, respectively.

Nontronite NAu-1 was exposed to moderate temperature and pressure conditions (250 and 300°C at 100 MPa pressure) in KCl brine to simulate burial diagenetic systems over accelerated time periods appropriate for laboratory experiments. Powder X-ray diffraction and transmission electron microscopy analysis of the coexisting mixed-layer and discrete 10 Å clay reaction products, and inductively coupled plasma-mass spectrometry analysis of the remaining fluids, indicated that the clay retained octahedral Fe and was identified as Fe-celadonite. The release of Fe from smectite during burial diagenesis has been hypothesized as a mechanism for magnetite authigenesis. High Al activity relative to Fe may be critical to the formation of an aluminous illite and any associated authigenic magnetite.

The magnitude of the postprandial hypotensive (PPH) response has been shown to be an independent risk factor for falls, fractures, and death. Despite this well-established risk, meal tests are rarely done in the falls clinic setting because of logistical issues. In order to better target potential PPH patients among older falling adults, this study examines which subject characteristics are associated with larger PPH responses. A total of 52 falls clinic patients (mean age 77.8 ± 0.9 years, 29 women, 23 men) were recruited for a 90 minute meal test. Significant variables were then entered into a stepwise multivariate linear model containing age, sex, presence of diabetes, presence of hypertension, baseline systolic blood pressure (SBP), and the orthostatic drop in SBP. Although further work is required, our study suggests that men, patients with higher blood pressure, and patients with an orthostatic drop might be more likely to have higher postprandial hemodynamic responses.

With the recent discovery of a dozen dusty star-forming galaxies and around 30 quasars at z > 5 that are hyper-luminous in the infrared (μ LIR > 1013 L⊙, where μ is a lensing magnification factor), the possibility has opened up for SPICA, the proposed ESA M5 mid-/far-infrared mission, to extend its spectroscopic studies toward the epoch of reionisation and beyond. In this paper, we examine the feasibility and scientific potential of such observations with SPICA’s far-infrared spectrometer SAFARI, which will probe a spectral range (35–230 μm) that will be unexplored by ALMA and JWST. Our simulations show that SAFARI is capable of delivering good-quality spectra for hyper-luminous infrared galaxies at z = 5 − 10, allowing us to sample spectral features in the rest-frame mid-infrared and to investigate a host of key scientific issues, such as the relative importance of star formation versus AGN, the hardness of the radiation field, the level of chemical enrichment, and the properties of the molecular gas. From a broader perspective, SAFARI offers the potential to open up a new frontier in the study of the early Universe, providing access to uniquely powerful spectral features for probing first-generation objects, such as the key cooling lines of low-metallicity or metal-free forming galaxies (fine-structure and H2 lines) and emission features of solid compounds freshly synthesised by Population III supernovae. Ultimately, SAFARI’s ability to explore the high-redshift Universe will be determined by the availability of sufficiently bright targets (whether intrinsically luminous or gravitationally lensed). With its launch expected around 2030, SPICA is ideally positioned to take full advantage of upcoming wide-field surveys such as LSST, SKA, Euclid, and WFIRST, which are likely to provide extraordinary targets for SAFARI.

Measurements in the infrared wavelength domain allow direct assessment of the physical state and energy balance of cool matter in space, enabling the detailed study of the processes that govern the formation and evolution of stars and planetary systems in galaxies over cosmic time. Previous infrared missions revealed a great deal about the obscured Universe, but were hampered by limited sensitivity.

SPICA takes the next step in infrared observational capability by combining a large 2.5-meter diameter telescope, cooled to below 8 K, with instruments employing ultra-sensitive detectors. A combination of passive cooling and mechanical coolers will be used to cool both the telescope and the instruments. With mechanical coolers the mission lifetime is not limited by the supply of cryogen. With the combination of low telescope background and instruments with state-of-the-art detectors SPICA provides a huge advance on the capabilities of previous missions.

SPICA instruments offer spectral resolving power ranging from R ~50 through 11 000 in the 17–230 μm domain and R ~28.000 spectroscopy between 12 and 18 μm. SPICA will provide efficient 30–37 μm broad band mapping, and small field spectroscopic and polarimetric imaging at 100, 200 and 350 μm. SPICA will provide infrared spectroscopy with an unprecedented sensitivity of ~5 × 10−20 W m−2 (5σ/1 h)—over two orders of magnitude improvement over what earlier missions. This exceptional performance leap, will open entirely new domains in infrared astronomy; galaxy evolution and metal production over cosmic time, dust formation and evolution from very early epochs onwards, the formation history of planetary systems.

Six hundred and forty four gamma-ray spectrometer assays of U and Th obtained within the late Caledonian Galway Granite western Ireland are presented. The data cover the range of granodiorites, adamellites and leucogranites (Murvey Granite) present in the batholith. There is an overall increase in U and Th abundances with petrological evolution. The broad scatter of values that characterizes the Murvey Granite reflects the geographically separate occurrences of this leucogranite. Rubidium and strontium data imply varying degrees of fractionation among these separate Murvey Granite occurrences. Y and HREE are notably enriched in the Murvey granite at Costelloe which also contains the highest Th levels amongst the leucogranites. Thorite, uraninite, monazite and Y-zircon are present in this leucogranite and are responsible for the observed enrichments in U, Th, Y and HREE.

Excavations at several locations in Verteba Cave have uncovered a large amount of human skeletal remains in association with faunal bones and Tripolye material culture. We aim to establish radiocarbon (14C) dates for eight sites and to evaluate whether these deposits are singular events, or slow accumulations over time. 14C measurements, along with stable carbon and nitrogen isotope data from human and faunal remains, were collected from 18 specimens. Stable isotope values were used to evaluate human and animal diet, and whether freshwater reservoir effects offset measured dates. We found diets of the sampled species had limited to no influence from freshwater resources. Human diet appears to be dominated by terrestrial plants and herbivores. Four new sites were identified as Eneolithic. Comparisons of dates from top and bottom strata for two sites (7 and 20) reveal coeval dates, and we suggest that these deposits represent discrete events rather than slow continuous use. Lastly, we identified dates from the Mesolithic (8490±45 BP, 8765±30 BP), Iron Age (2505±20 BP), Slavic state era (1315±25 BP), and Medieval Period (585±15 BP), demonstrating periodic use of the cave by humans prior to and after the Eneolithic.

The SPICA mid- and far-infrared telescope will address fundamental issues in our understanding of star formation and ISM physics in galaxies. A particular hallmark of SPICA is the outstanding sensitivity enabled by the cold telescope, optimised detectors, and wide instantaneous bandwidth throughout the mid- and far-infrared. The spectroscopic, imaging, and polarimetric observations that SPICA will be able to collect will help in clarifying the complex physical mechanisms which underlie the baryon cycle of galaxies. In particular, (i) the access to a large suite of atomic and ionic fine-structure lines for large samples of galaxies will shed light on the origin of the observed spread in star-formation rates within and between galaxies, (ii) observations of HD rotational lines (out to ~10 Mpc) and fine structure lines such as [C ii] 158 μm (out to ~100 Mpc) will clarify the main reservoirs of interstellar matter in galaxies, including phases where CO does not emit, (iii) far-infrared spectroscopy of dust and ice features will address uncertainties in the mass and composition of dust in galaxies, and the contributions of supernovae to the interstellar dust budget will be quantified by photometry and monitoring of supernova remnants in nearby galaxies, (iv) observations of far-infrared cooling lines such as [O i] 63 μm from star-forming molecular clouds in our Galaxy will evaluate the importance of shocks to dissipate turbulent energy. The paper concludes with requirements for the telescope and instruments, and recommendations for the observing strategy.

IR spectroscopy in the range 12–230 μm with the SPace IR telescope for Cosmology and Astrophysics (SPICA) will reveal the physical processes governing the formation and evolution of galaxies and black holes through cosmic time, bridging the gap between the James Webb Space Telescope and the upcoming Extremely Large Telescopes at shorter wavelengths and the Atacama Large Millimeter Array at longer wavelengths. The SPICA, with its 2.5-m telescope actively cooled to below 8 K, will obtain the first spectroscopic determination, in the mid-IR rest-frame, of both the star-formation rate and black hole accretion rate histories of galaxies, reaching lookback times of 12 Gyr, for large statistically significant samples. Densities, temperatures, radiation fields, and gas-phase metallicities will be measured in dust-obscured galaxies and active galactic nuclei, sampling a large range in mass and luminosity, from faint local dwarf galaxies to luminous quasars in the distant Universe. Active galactic nuclei and starburst feedback and feeding mechanisms in distant galaxies will be uncovered through detailed measurements of molecular and atomic line profiles. The SPICA’s large-area deep spectrophotometric surveys will provide mid-IR spectra and continuum fluxes for unbiased samples of tens of thousands of galaxies, out to redshifts of z ~ 6.

The physical processes driving the chemical evolution of galaxies in the last ~ 11Gyr cannot be understood without directly probing the dust-obscured phase of star-forming galaxies and active galactic nuclei. This phase, hidden to optical tracers, represents the bulk of the star formation and black hole accretion activity in galaxies at 1 < z < 3. Spectroscopic observations with a cryogenic infrared observatory like SPICA, will be sensitive enough to peer through the dust-obscured regions of galaxies and access the rest-frame mid- to far-infrared range in galaxies at high-z. This wavelength range contains a unique suite of spectral lines and dust features that serve as proxies for the abundances of heavy elements and the dust composition, providing tracers with a feeble response to both extinction and temperature. In this work, we investigate how SPICA observations could be exploited to understand key aspects in the chemical evolution of galaxies: the assembly of nearby galaxies based on the spatial distribution of heavy element abundances, the global content of metals in galaxies reaching the knee of the luminosity function up to z ~ 3, and the dust composition of galaxies at high-z. Possible synergies with facilities available in the late 2020s are also discussed.

Background. This paper examines genetic and environmental contributions to risk of cannabis dependence.

Method. Symptoms of cannabis dependence and measures of social, family and individual risk factors were assessed in a sample of 6265 young adult male and female Australian twins born 1964–1971.

Results. Symptoms of cannabis dependence were common: 11·0% of sample (15·1% of men and 7·8% of women) reported two or more symptoms of dependence. Correlates of cannabis dependence included educational attainment, exposure to parental conflict, sexual abuse, major depression, social anxiety and childhood conduct disorder. However, even after control for the effects of these factors, there was evidence of significant genetic effects on risk of cannabis dependence. Standard genetic modelling indicated that 44·7% (95% CI = 15–72·2) of the variance in liability to cannabis dependence could be accounted for by genetic factors, 20·1% (95% CI = 0–43·6) could be attributed to shared environment factors and 35·3% (95% CI = 26·4–45·7) could be attributed to non-shared environmental factors. However, while there was no evidence of significant gender differences in the magnitude of genetic and environmental influences, a model which assumed both genetic and shared environmental influences on risks of cannabis dependence among men and shared environmental but no genetic influences among women provided an equally good fit to the data.

Conclusions. There was consistent evidence that genetic risk factors are important determinants of risk of cannabis dependence among men. However, it remains uncertain whether there are genetic influences on liability to cannabis dependence among women.

New experimental and theoretical studies of low-density amorphous solid water (H2O(as)) and of polycrystalline ice lh are reported and integrated with other available data. A variety of evidence is put forward to support the conclusion that low-density H20(as) is derived from ice lh by slightly increasing the dispersion in the O—O separation and by introducing a distribution O—O—O angles (width c. 8°). Our theoretical analysis focusses attention on the consequences of strong intermolecular coupling of OH oscillators. The vibrational modes of both ice lh and H20(as) are found to be complex mixtures of molecular motions, so the identification of regions of the Raman or infrared spectra of these materials with particular isolated molecule modes is not useful. The theory developed gives a good, but not perfect, account of the OH stretching regions of the observed Raman and infrared spectra of ice lh and, to a lesser degree of low-density H20(as).

The current study examined a stage-based alcohol use trajectory model to test for potential causal effects of earlier drinking milestones on later drinking milestones in a combined sample of two cohorts of Australian monozygotic and same-sex dizygotic twins (N = 7,398, age M = 30.46, SD = 2.61, 61% male, 56% monozygotic twins). Ages of drinking, drunkenness, regular drinking, tolerance, first nontolerance alcohol use disorder symptom, and alcohol use disorder symptom onsets were assessed retrospectively. Ages of milestone attainment (i.e., age-of-onset) and time between milestones (i.e., time-to-event) were examined via frailty models within a multilevel discordant twin design. For age-of-onset models, earlier ages of onset of antecedent drinking milestones increased hazards for earlier ages of onset for more proximal subsequent drinking milestones. For the time-to-event models, however, earlier ages of onset for the “starting” milestone decreased risk for a shorter time period between the starting and the “ending” milestone. Earlier age of onset of intermediate milestones between starting and ending drinking milestones had the opposite effect, increasing risk for a shorter time period between the starting and ending milestones. These results are consistent with a causal effect of an earlier age of drinking milestone onset on temporally proximal subsequent drinking milestones.

A novel pressure sensor is proposed exhibiting generative properties fromdisplacement-induced ionic charge separation in gel electrolytes. Amechano-ionic or ‘piezo-ionic’ effect, in analogy to thewell-known piezoelectric effect, is hypothesized to originate from a differencein mobilities between cationic and anionic species causing a localized ioniccharge gradient upon application of pressure. This gradient can be detected as avoltage or current by using copper electrodes placed at the sides or at regularintervals along a surface of the gel. The voltage generated may be a result ofthe local concentration gradient induced by the deformation of the gel orperhaps is the result of some ions moving faster through the porous gel thanothers. In this work, ionic polymer gels based on Poly(vinylidenefluoride-hexafluoropropylene) (PVDF-HFP) co-polymer were synthesized insitu to incorporate an organic electrolyte consisting ofbis(trifluoromethane)sulfonimide lithium salt in propylene carbonate. With twoelectrodes placed under the gel, the samples were subjected to a sinusoidalmechanical force while open circuit voltage was measured to determine therelationship between electrical signal and mechanical input. The voltagesgenerated are 10’s of mV in magnitude at 1 kPa. Results suggest amaximum sensitivity of 25 µV/Pa at 10 mHz, comparable to the voltagesexpected in piezoelectric polymers such as PVDF (44 µV/Pa for similardimensions). The non-aqueous, solid-state ionic gels presented in this workprovide improved stability and is less prone to evaporation than its aqueous,hydrogel based counterpart. The new mechanism of sensing provides an alternativeto the more rigid and less stretchable piezoelectric sensors.