Predicted Melt Curve and Liquid Shear Viscosity of RDX up to 30 GPa

Recent grain scale simulations of HMX and TATB have shown that predictions for hot spot formation in high explosives are particularly sensitive to accurate determinations of the pressure-dependent melt curve and the shear viscosity of the liquid phase. These physics terms are poorly constrained beyond ambient pressure for the explosive RDX. We adopt an all-atom modeling approach using molecular dynamics (MD) simulations to predict the melt curve of RDX near to detonation conditions (30 GPa) and determine the shear viscosity of the liquid as a function of temperature and pressure above the melt curve. Phase-coexistence simulations were used to determine the melt curve, which is predicted to vary by almost 1100 K as the pressure increases from 0 GPa to 30 GPa. Equilibrium MD simulations and the Green-Kubo formalism were used to obtain the pressure-temperature dependent shear viscosity. The shear viscosity of RDX is predicted to be of similar magnitude to the viscosity of TATB at low GPa-range pressures, and to be roughly an order of magnitude lower than the viscosity of HMX. The temperature dependence of the shear viscosity is Arrhenius at a given pressure, and the exponential pre-factor and activation term exhibit a strong, yet complicated, pressure dependence. An empirical pressure-temperature dependent function for RDX shear viscosity is developed that simultaneously captures a wide range of MD predictions while taking an analytic form that extrapolates smoothly beyond the fitted regime. The relative strength of the pressure and temperature dependencies of these two physics terms is found to be of similar magnitude for RDX, HMX, and TATB, which motivates incorporating these results in future RDX grain scale modeling.

Copeptin response to acute physical stress during hypohydration: An exploratory secondary analysis

Purpose: Plasma copeptin (a surrogate marker of arginine vasopressin) is increasingly being used as a marker of stress in several research and clinical contexts. However, the response to an acute physical stressor in healthy adults has not yet been tested meaning it is unclear whether copeptin reflects dynamic changes in stress or whether this is moderated by different basal copeptin concentrations and how this relates to other stress hormones. Methods: Secondary data analysis in a subsample of participants (n = 7; n = 1 woman) who opted-in for muscle biopsies in a randomised crossover study investigating the effects of acute hypohydration (HYPO) versus rehydration (RE) on metabolism. Results: Plasma copeptin responded to the muscle biopsy stress stimulus, with a similar magnitude of difference according to basal concentrations during HYPO and RE; however, the peak was higher and concentrations typically took longer to return to baseline during HYPO. Despite large differences in copeptin concentrations, adrenocorticotropin hormone (ACTH) and cortisol showed a similar trends in response to the biopsies, regardless of hydration status. Conclusion: Copeptin responded dynamically to an acute physical stressor (muscle biopsy). HYPO induced higher basal copeptin concentrations compared to RE, and resulted in a higher and prolonged copeptin response. Further research should investigate the mechanisms underlying the lack of differences in ACTH and cortisol according to hydration status.

Thermoelectric Power in Ce Systems with Unstable Valence

In this paper, we report on a few exemplary tests of the applicability of analysis based on the interconfiguration fluctuation model (ICF) for a description of the temperature dependence of the thermoelectric power, S(T). The examples include a series of alloys: CeNi2(Si1−yGey)2, Ce(Ni1−xCux)2Si2, and the fluctuating valence (FV) compound CeNi4Ga. The two series develop from CeNi2Si2 being the FV system, where the f states occupation increases progressively with the Ge or Cu substitution. We find here that the ICF model parameters are of similar magnitude both for the analysis of the temperature dependence of the magnetic susceptibility and thermoelectric power. The ICF-type model appears to be a powerful tool for the analysis of S(T) dependences in Ce-based FV compounds and alloys.

Using structural priming to test links between constructions: English caused-motion and resultative sentences inhibit each other

Cognitive-linguistic theories commonly model speakers’ grammatical knowledge as a network of constructions related by a variety of associative links. The present study proposes that structural priming can provide psycholinguistic evidence of such links, and crucially, that the method can be extended to non-alternating constructions (i.e., constructions that differ in both form and meaning). In a comprehension priming experiment using the “maze” variant of self-paced reading, English caused-motion sentences were found to have an inhibitory effect by slowing down participants’ subsequent processing of resultatives, and vice versa, providing evidence that speakers store distinct but related representations for the constructions. Priming effects of a similar magnitude emerged in both directions, suggesting that the constructions are bidirectionally related, while not supporting previous claims about a metaphorical asymmetry between the patterns. Moreover, priming was only marginally affected when prime and target contained the same rather than different verbs, demonstrating that cross-constructional priming in comprehension can be observed in the absence of a “lexical boost”. The results raise questions for follow-up research on the role of inhibition in the grammatical network and the extension of structural priming to other types of constructional links.

SI on economic costs of invasions - Feeling the pinch: global economic costs of crayfish invasions and comparison with other aquatic crustaceans

Despite voluminous literature identifying invasive species impacts, understandings of monetary costs remain limited. Recently, profound impacts have been attributed to invasive crustaceans, but associated monetary costs lack synthesis. Here, we analyse globally reported costs of invasive freshwater crayfish across taxonomic, spatial and temporal descriptors. Moreover, we compare their cost magnitude to other invasive crustaceans — crabs, amphipods and lobsters. Between 2000 and 2020, crayfish caused US$ 1.28 billion in reported costs; the vast majority (95%) attributed to Astacidae (principally the signal crayfish Pacifastacus leniusculus) and the remainder to Cambaridae. According to reports, crayfish costs mostly impacted European economies (US$ 1.23 billion), followed by costs reported for North America and Asia. Despite well-known damages caused by invasive crayfish, costs were unreported elsewhere, highlighting knowledge gaps and challenges in cost quantifications. Invasive crayfish costs increased exponentially in the last two decades, averaging at US$ 61 million per-annum. Invasive crabs caused costs of similar magnitude (US$ 1.25 billion; US$ 53 million per-annum) but were mostly confined to North America (95%). Damage-related costs dominated for both crayfish (83%) and crabs (99%), with management spending lacking. Reported economic impacts from amphipods (US$ 178.8 thousand) and lobsters (US$ 44.6 thousand) were considerably lower. We identify burgeoning economic costs from these invasive groups yet highlight pervasive knowledge gaps at multiple scales. Further cost reporting is required to better-ascertain the true scale of monetary costs caused by invasive aquatic crustaceans.

Capturing Subjective Age, Subjective Life Expectancy, and Their Links With Older Adults’ Health: The Dutch Longitudinal Aging Study Amsterdam

Objectives: This study compares the associations of two subjective lifetime perspectives, subjective age (SA) and subjective life expectancy (SLE), with physical performance, self-rated health, and depressive symptoms. Methods: 64 91-year-old participants were selected from three waves of the Longitudinal Aging Study Amsterdam (2008/09, 2011/12, 2015/16; n = 1822 participants, n = 3500 observations) that included graphical and numerical measures of SA and SLE. We used generalized estimating equations to examine their associations with health. Results: Associations of SA/SLE with health were weaker for physical performance than for self-rated health and depressive symptoms. The associations of SA and SLE with physical performance were of similar magnitude but with self-rated health depended on the type of measure. Depressive symptoms, instead, showed a stronger association with SA than with SLE. Graphical measures showed weaker associations than numerical measures. Discussion: The way in which subjective lifetime perspectives and health are conceptualized and measured influences the strength of their associations.

Microplastics Contamination versus Inorganic Particles: Effects on the Dynamics of Marine Dissolved Organic Matter

Microplastic contamination has been linked to a range of impacts on aquatic environments. One important area that is only beginning to be addressed is the effect of microplastics on marine carbon cycling and how these compare to the effects related to inorganic particles typically present in ocean waters. The present study explores these impacts on dissolved organic matter dynamics by comparing three scenarios: a particle-free environment, a particle-enriched system with polystyrene microplastics, and a particle-enriched system with inorganic particles (water insoluble SiO2). Natural marine organic matter was obtained by culturing a non-axenic strain of Chaetoceros socialis in 2 L flasks under each of three scenarios. Following the diatom growth phase, filtered samples from the three flasks containing dissolved organic matter and bacteria were incubated separately in the dark for 5 days to monitor changes in dissolved organic matter. Chromophoric dissolved organic matter (CDOM), a bulk optical property, was monitored daily to examine changes in its quality and quantity and to compare degradation dynamics in the three systems. CDOM absorbance (quantity) remained higher in the control with respect to particle-enriched systems, suggesting that the presence of particles led to different rates of CDOM production and degradation. Using indicators for CDOM that could be related to microbial activity, results showed a higher CDOM alteration in the particle-enriched systems. These results indicate that microplastics have a potential role in modifying marine organic matter dynamics, on a similar magnitude to that of biogenic inorganic particles. Given their increasing concentrations of marine ecosystems, their role in marine microbial processing of organic matter needs to be better understood.

ARTS, CULTURE AND TOURISM AS VERITABLE INSTRUMENTS OF A STABLE NIGERIAN POLITY: THE NEED FOR AN INCLUSIVE PUBLIC POLICY

Like in most other nations of the world, the round leather game (football) is one sport that triggers the display of solidarity among Nigerians irrespective of tribe, religion and other social affiliations. Another experience of a similar magnitude of show of solidarity in this country is the Festivals of Arts and Culture which also displays the potentials in tourism. This study examined the potentials of Arts, Culture and Tourism as instruments of unification of Nigerians for purposes of a stable Nigerian political environment as well as the need for an inclusive public policy. Data was obtained from secondary materials while the mode of analysis was content analysis. The secondary materials include – books, journals, periodicals, newspapers, the internet, etc. The sociological and anthropological modernized theory, Durkheim (1997) was adopted as the theoretical framework of the study. Findings showed that, the Festivals of Arts and Culture across this country are often associated with so much fanfare, enthusiasm, relaxation, show of solidarity, oneness, that people tend to forget their social identities, groups, ethnicities, religions and other social inclinations. Hence, this paper suggested that government evolves an inclusive policy that would regularize and formalize the organization of Festivals of Arts and Culture in this country. The paper came to the conclusion that such festivals with great potentials for the unification of nationals should be harnessed for purposes of the peaceful co-existence of all Nigerians. The paper noted that this could only be realized through a well-articulated and inclusive public policy on Arts, Culture and Tourism.

Finding Antarctica’s Pole of Inaccessibility

Antarctica’s Pole of Inaccessibility (Southern Pole of Inaccessibility (SPI)) is the point on the Antarctic continent farthest from its edge. Existing literature exhibits disagreement over its location. Using two revisions of the Scientific Committee on Antarctic Research’s Antarctic Digital Database, we calculate modern-day positions for the SPI around 10 years apart, based on the position of the “outer” Antarctic coastline, i.e. its boundary with the ocean. These show that the position of the SPI in the year 2010 was around 83° 54’ S, 64° 53’ E, shifting on the order of 1 km per year as a result of changes of a similar magnitude in the Amery, Ronne-Filchner and Ross Ice Shelves. Excepting a position of the SPI calculated by British Antarctic Survey in 2005, to which it is very close, our newly calculated position differs by 150–900 km from others reported in the literature. We also consider the “inner” SPI, defined by the coastline with floating ice removed. The position of this SPI in 2010 is estimated as 83°37’ S, 53° 43’ E, differing significantly from other reported positions. Earlier cartographic data are probably not sufficiently accurate to allow its rate of change to be calculated meaningfully.

Evaluation of the Worldwide Occurrence of Rabies in Dogs and Cats Using a Simple and Homogenous Framework for Quantitative Risk Assessments of Rabies Reintroduction in Disease-Free Areas through Pet Movements

Dog and cat rabies cases imported from rabies enzootic countries represent a major threat for areas that have acquired rabies-free status and quantitative risk analyses (QRAs) are developed in order to assess this risk of rabies reintroduction through dog and cat movements. Herein we describe a framework to evaluate dog and cat rabies incidence levels in exporting countries along with the associated uncertainty for such QRAs. For enzootic dog rabies areas (EDRAs), we extended and adapted a previously published method to specify the relationship between dog rabies vaccination coverage and canine rabies incidence; the relationship between dog and cat rabies incidences; and then to predict annual dog and cat rabies incidences. In non-enzootic dog rabies areas (nEDRAs), we provided annual incidence based on declared dog and cat rabies cases. For EDRAs, we predicted an annual incidence potentially greater than 1.5% in dogs and about ten times lower in cats with a high burden in Africa and Asia but much lower in Latin America. In nEDRAs, the occurrence of rabies was lower and of similar magnitude in dogs and cats. However, wildlife could still potentially infect dogs and cats through spillover events. This framework can directly be incorporated in QRAs of rabies reintroduction.