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Seismic reflection data and implicitly sonic velocity are undoubtedly the most important source of information for large-scale subsurface characterization. Yet, deriving reservoir and fluid flow properties from acoustic data is still challenging in carbonates, which display large acoustic velocity variations that contest many of the conventional assumptions regarding wave propagation in porous media. In this comprehensive study on 370 carbonate samples (247 limestones and 123 dolomites), we re-evaluate the impact of mineral velocity on bulk rock acoustic properties of dolomite and limestone by assessing the link between sonic velocity and the rock’s pore geometry. We quantify pore size and pore network complexity using parameters from both digital image analysis (DIA) and the extended Biot theory (EBT). We then compare DIA and EBT parameters to assess the impact of pore network geometry versus mineral velocity on the acoustic velocity of carbonate rocks. We explore the usefulness of EBT parameter γk in improving permeability estimates. Published values of velocity indicate that dolomites exhibit higher velocities than limestones at any given porosity. Our laboratory measurements of acoustic velocity, however, reveal that both dolomites and limestones show extreme variations in sonic velocities where samples with compressional velocity of ~5000 m/s may range in porosity from 5% to 25% and samples with porosity of ~20% may range in velocity from ~4000 m/s to 5700 m/s. Through the quantitative assessment of the pore network in our samples we document that pore network geometry has much more impact on the acoustic velocity of carbonates than variations in mineralogy, in this case dolomite and calcite. Most of the dolostone samples studied are dominated by small pores, resulting in relatively low velocities for their given porosity, while limestones with similar velocity–porosity values often possess simpler pore networks with larger pores. This pore size difference offsets the faster velocity of dolomite. The extended Biot theory parameter γk, captures this variation in pore size and internal geometry and exhibits a strong correlation to specific surface. Moreover, γk captures the impact of internal pore geometry on acoustic velocity, providing the basis for challenging existing assumptions regarding the importance of mineral velocity. By quantifying internal geometry, γk can improve permeability estimates in reservoir characterization and enhance evaluations of producibility and injectability. With that, it has direct implications on general geophysics, hydrocarbon exploration, and CCS initiatives.

The international pet trade is a major driver of non-native species spread, including species both sold in the trade, and organisms incidentally transported alongside. Here, we document the discovery of invasive zebra mussels, Dreissena polymorpha, in Germany, transported alongside a commonly traded garden pond snail and European native, Viviparus viviparus, ordered from a German pet website. We highlight that the trade poses yet another way in which zebra mussels and other invasive species can expand their invaded range into novel ecosystems. We call for stricter biosecurity enforcement towards sellers, and encourage raising awareness amongst customers to inhibit the further spread of invasive species through the pet trade.

Predicting the myriad effects of climate change on ecological communities is a major challenge for scientists, and to date relatively few studies have focused on the effects of sea freshening on species interactions. In particular, changes in keystone species predatory effects could be pervasive. Here, we assess the consequences of decreasing salinity on the ecological impact exerted by a keystone predatory sea star, Asterias rubens. We quantified sea star functional responses (FRs; per capita predation as a function of prey density) under decreasing salinity treatments aligned with climate change projections (18ppt, 15ppt, 12ppt). Furthermore, we combined FRs with larval recruitment estimates, i.e. ecological “Impact Potential”, to act as an ecological indicator of predator population-level responses under this environmental change. Attack and maximum feeding rates of sea stars were reduced by decreasing salinities, with no instances of predation found at 12ppt. Given that decreasing salinities also reduced larval sea star recruitment, the overall Impact Potential of this keystone predator species was lessened by decreased salinity. Sea freshening projections by the end of this century could thus drive significant decreases in the effects of this keystone predator, with serious implications for the structuring and functioning of ecological communities.

Electron microscopy can reveal a material’s chemical structure down to the atomic level, but has so far been blind to isotopic differences. Here the authors are able to map isotope concentrations in graphene by measuring the probability of ejecting atoms, demonstrating a ‘mass spectrometer in the microscope’.

A site assessment was conducted at a coal fired power plant in South Africa to determine whether surrounding soils were being enriched with trace metals resulting from activities at the power plant. It was found that deposition of fly ash from the flue stacks and the ash dump along with deposition of coal dust from the coal stock yard were the activities most likely to lead to such enrichment. Eighty topsoil samples were gathered and analysed for total metal content. Results were interpreted within the context of background values. It was found that concentrations of As, Cu, Mn, Ni and Pb exceeded local screening levels, but only As and Pb could be confidently attributed to anthropogenic intervention and actual enrichment.

Nature Communications 7: Article number: 13040 (2016); Published: 10 October 2016; Updated: 30 August 2017 This Article contains typographical errors in Fig. 3 and Equation 23. In Fig. 3c, the labels ‘12C’ and ‘13C’ in the key should be reversed. The correct version of Fig. 3 appears below as Fig. 1.

We report the preparation of freestanding membranes of cross-linked gold nanoparticles (GNPs) and demonstrate their application as electromechanical sensors for volatile organic compounds (VOCs). First, we show that the fundamental vibrational mode frequency of electrostatically excited GNP-membranes shifts significantly when exposing them to solvent vapors. We attribute this effect mainly to the reduction of the membranes’ pre-stress. Second, the relief in pre-stress upon analyte sorption can also be detected via quasi-static actuation of the membranes. In this case, the increase of the deflection amplitudes at constant bias voltages can be measured as the sensor signal and correlated to the analyte’s concentration. Additionally, we propose a facile route to the fabrication of such hybrid MEMS/NEMS sensors using layer-by-layer spin-coating and contact printing.

En las últimas décadas está teniendo lugar un discreto, aunque continuo, proceso de convergencias y fertilización cruzada o entrecruzamiento entre, de un lado, los derechos fundamentales conocidos como civiles y políticos y, de otro lado, los esenciales si bien frecuentemente subestimados derechos humanos conocidos como derechos económicos, sociales y culturales. Desde un punto de vista teórico, los autores admiten ampliamente en la actualidad que ambos «grupos» de derechos humanos son indivisibles, interdependientes e interrelacionados, en el sentido de que ninguna categoría puede en puridad cumplir con sus tareas protectoras si la otra está siendo sistemáticamente violada y/o sacrificada en el altar de un utópico bien común. Además, cada derecho humano genera per se múltiples «oleadas de deberes» que deben ser abordadas por los Estados y por sus agentes. Desde una perspectiva académica, esas oleadas se reconducen tradicionalmente a tres tipos de obligaciones: respetar, proteger y cumplir cada derecho humano. La práctica y la jurisprudencia que se viene desarrollando por el Tribunal Europeo de Derechos Humanos y por el Comité Europeo de Derechos Sociales ponen de manifiesto lo que en verdad se esconde detrás de esos conceptos teóricos, ya sea con relación a los tipos de deberes que pesan sobre los Estados y cuya protección viene encomendada a cada órgano internacional, ya sea con respecto a los fuertes vínculos que existen y seguirán existiendo entre cada «grupo» de derechos humanos. Por añadidura, el Tribunal Europeo de Derechos Humanos y el Comité Europeo de Derechos Sociales se están remitiendo crecientemente cada uno a la jurisprudencia del otro, especialmente desde el momento en que al Comité Europeo se le atribuyó la competencia de examinar reclamaciones colectivas y, con ella, la de ejercer poderes cuasijudiciales. Aunque limitada por diversos factores, la armonización de métodos, vocabulario, enfoques e interpretaciones se va abriendo camino y, con el tiempo, avanzando hacia la práctica realización de una plena igualdad de trato entre los derechos humanos civiles y sociales.

Despite the importance of South Africa's Afromontane grasslands for ecosystem services (water supply and biodiversity), soil organic carbon (SOC) research remains limited. These grasslands evolved with fire, and fire exclusion leads to native plant afforestation. This study investigated SOC fractions and origin to understand the impact of fire‐exclusion‐driven afforestation and aspect on SOC storage in Afromontane grasslands. This study in Cathedral Peak Research Catchments, initiated in the 1940s, compared an afforested fire‐excluded site (AF) to a periodically burnt (accidental fires, 2–5 years interval) grassland (PB) within the same catchment (Catchment‐IX). Additionally, it compared a south‐facing periodically burnt grassland (Catchment‐IX) to a north‐facing biennially burnt grassland (Catchment‐VI). Soil samples collected at soil‐depth increments (0–5, 5–10, 10–15, 15–20, 20–30, 30–60 and 60–100 cm) revealed that, within Catchment IX, PB had more topsoil SOC stocks and microbial activity than AF but similar active carbon (C) concentrations. As expected, δ13C values revealed that SOC in PB originates from C4 grasses, whilst it mostly originates from C3 plants in AF. The south‐facing slope (Catchment‐IX) had more SOC stocks, microbial activity and active C compared to the north‐facing slope (Catchment‐VI). Fire‐exclusion‐driven afforestation changed SOC input from roots to litter, thus reducing SOC storage. Cooler south‐facing slopes are better C reservoirs. Afromontane grasslands show greater potential for C sequestration than afforested systems. [ABSTRACT FROM AUTHOR]

Metazoan genes are embedded in a rich milieu of regulatory information that often includes multiple enhancers possessing overlapping activities. In this study, we employ quantitative live imaging methods to assess the function of pairs of primary and shadow enhancers in the regulation of key patterning genes-knirps, hunchback, and snail-in developing Drosophila embryos. The knirps enhancers exhibit additive, sometimes even super-additive activities, consistent with classical gene fusion studies. In contrast, the hunchback enhancers function sub-additively in anterior regions containing saturating levels of the Bicoid activator, but function additively in regions where there are diminishing levels of the Bicoid gradient. Strikingly sub-additive behavior is also observed for snail, whereby removal of the proximal enhancer causes a significant increase in gene expression. Quantitative modeling of enhancer–promoter interactions suggests that weakly active enhancers function additively while strong enhancers behave sub-additively due to competition with the target promoter.

Background: Prior work has shown that transcranial alternating current stimulation (tACS) of parietooccipital alpha oscillations (8–14 Hz) can modulate working memory (WM) performance as a function of the phase lag to endogenous oscillations. However, leveraging this effect using real-time phase-tuned tACS has not been feasible so far due to stimulation artifacts preventing continuous phase tracking. Objectives and hypothesis: We aimed to develop a system that tracks and adapts the phase lag between tACS and ongoing parietooccipital alpha oscillations in real-time. We hypothesized that such real-time phase-tuned tACS enhances working memory performance, depending on the phase lag. Methods: We developed real-time phase-tuned closed-loop amplitude-modulated tACS (CLAM-tACS) targeting parietooccipital alpha oscillations. CLAM-tACS was applied at six different phase lags relative to ongoing alpha oscillations while participants (N = 21) performed a working memory task. To exclude that behavioral effects of CLAM-tACS were mediated by other factors such as sensory co-stimulation, a second group of participants (N = 25) received equivalent stimulation of the forehead. Results: WM accuracy improved in a phase lag dependent manner (p = 0.0350) in the group receiving parietooccipital stimulation, with the strongest enhancement observed at 330° phase lag between tACS and ongoing alpha oscillations (p = 0.00273, d = 0.976). Moreover, across participants, modulation of frontoparietal alpha oscillations correlated both in amplitude (p = 0.0248) and phase (p = 0.0270) with the modulation of WM accuracy. No such effects were observed in the control group receiving frontal stimulation. Conclusions: Our results demonstrate the feasibility and efficacy of real-time phase-tuned CLAM-tACS in modulating both brain activity and behavior, thereby paving the way for further investigation into brain-behavior relationships and the exploration of innovative therapeutic applications.

Abstract Background Evolution is a unifying theme in biology and its understanding is essential to address sustainability problems. However, many people across the world do not understand evolution. Textbooks are among the most widely used educational resources and the way they depict evolution may greatly impact students’ scientific literacy in evolution. In this paper we investigate which evolution concepts are addressed in European science textbooks, from the 1st to the 9th grade. A content analysis using the ‘Framework for the Assessment of school Curricula on the presence of Evolutionary concepts”, was performed on textbooks from eight European countries: Belgium, Cyprus, Czech Republic, Greece, Italy, Netherlands, Portugal and Slovenia. At least two experienced coders per country independently analysed the texts, images and activities, discussed the results and reached a final consensus. Results Our results show that textbooks lack or rarely address concepts considered important for evolution understanding, notably the processes driving evolution and their daily life implications, limiting opportunities for education for sustainability. Conclusions We recommend that science textbooks emphasize evolution and its processes since the first school years. This recommendation is particularly relevant for the analysed textbooks from Cyprus and Belgium, that cover less than 45% of the concepts important to evolution literacy.

The international pet trade is a major driver of non-native species spread, including species both sold in the trade, and organisms incidentally transported alongside. Here, we document the discovery of invasive zebra mussels, Dreissena polymorpha, in Germany, transported alongside a commonly traded garden pond snail and European native, Viviparus viviparus, ordered from a German pet website. We highlight that the trade poses yet another way in which zebra mussels and other invasive species can expand their invaded range into novel ecosystems. We call for stricter biosecurity enforcement towards sellers, and encourage raising awareness amongst customers to inhibit the further spread of invasive species through the pet trade. [ABSTRACT FROM AUTHOR]