Small-scale Changes Research Articles

Past, present and future global mangrove primary productivity

Mangrove productivity is crucial for the global carbon cycle, yet previous research has mostly focused on small-scale temporal changes or static global patterns, with limited investigation into global or regional temporal trends. This study used existing data on mangrove leaf litter to model mangrove Net Primary Productivity (NPP) on a monthly timescale from 1980 to 2094 across global regions defined by the Marine Ecoregions of the World framework. The models showed a slight global decrease in NPP of approximately 1.4 %, from 239.2 ± 87.6 Tg yr−1 (1980–1990) to 235.9 ± 81.9 Tg yr−1 (2085–2094). However, significant regional changes were identified, including substantial increases in NPP in the Southwest Australian Shelf (60.58 ± 97.9 %), the Warm Temperate Northeast Pacific (43.75 ± 65.7 %), and the Warm Temperate Northwest Pacific (31.55 ± 55.7 %), as well as decreases in Southeast Asian provinces like the Java Transitional (11.45 ± 6.2 %) and Western Coral Triangle (7.61 ± 9.6 %). These findings highlight previously unreported regional shifts in mangrove productivity, which could significantly impact carbon sequestration and the transfer of organic matter to adjacent ecosystems.

Study on improved control strategy of virtual synchronous generator

Virtual synchronous generator (VSG) control technology for photovoltaic, energy storage, wind power, and other new energy to provide flexibility in the grid interface characteristics, is conducive to improving the stability of the power system, and has been widely considered by many scholars. Firstly, an improved VSG control method is proposed through simulation and analysis, which realizes the complete decoupling of the frequency response time constant and the inertia quantity of the active power control loop and reduces the complexity of the parameter design of the VSG system. Secondly, to avoid the frequent action of the VSG system caused by small-scale frequency change perturbation, this study proposes a VSG frequency optimization control method for VSG frequency control with rated angular velocity ωset feedforward composed of multivariate factors when considering a primary frequency regulation dead zone. Thirdly, the impact of VSG parameter design on the system is investigated through the system response characteristics of power scheduling, primary frequency regulation at the grid connection, and the small-signal dynamic characterization of the improved VSG. Finally, Simulation and experimental verification yielded an active power overshoot of 7% and a maximum frequency deviation of 0.17 Hz for the improved system. The improved control method resulted in an improvement of 0.1 s in the frequency response time and a reduction of 0.15 Hz in the oscillation amplitude. The response speed of the improved control method is much better, while the oscillation amplitude is reduced to meet the grid's regulation requirements. The simulation and experimental analysis verify the feasibility of the improved VSG control method.

Cellular Characteristics and Protein Signatures of Human Adipose Tissues from Donors With or Without Advanced Coronary Artery Disease.

Background/Objectives: Perivascular adipose tissue (PVAT) exerts a paracrine effect on blood vessels and our objective was to understand PVAT molecular signatures related to cardiovascular disease. Methods: We studied two groups: those undergoing mitral valve repair/replacement (VR, n = 16) and coronary artery bypass graft (CABG, n = 38). VR donors did not have coronary artery disease, whereas CABG donors had advanced coronary artery disease. Clinical and tissue pathologies and proteomics from adipose tissue were assessed. Results: Donors undergoing VR had a lower body mass index (p = 0.01), HbA1C (p = 0.0023), and incidence of diabetes (p = 0.022) compared to CABG. VR donors were overall healthier, with higher cardiac function compared to CABG donors, based on ejection fraction. Although adipose histopathology between groups was not markedly different, PVAT had smaller and more adipocytes compared to subcutaneous adipose tissues. These differences were validated by whole specimen automated morphological analysis, and anisotropy analysis showed small (2.8-7.5 μm) and large (22.8-64.4 μm) scale differences between perivascular and subcutaneous adipose tissue from CABG donors, and small scale changes (2.8-7.5 μm) between perivascular and subcutaneous adipose tissue from VR donors. Distinct protein signatures in PVAT and subcutaneous adipose tissue include those involved in secretion, exosomes and vesicles, insulin resistance, and adipocyte identity. Comparing PVAT and subcutaneous adipose tissue from CABG donors, there were 82 significantly different proteins identified with log fold change ≥ 0.3 or ≤-0.3 (p < 0.05). Using this threshold, there were 36 differences when comparing PVAT and subcutaneous adipose tissue from VR donors, 58 differences when comparing PVAT from CABG or VR donors, and 55 when comparing subcutaneous adipose tissue from CABG vs. VR donors. Conclusions: Routine histopathology cannot differentiate between PVAT from donors with or without coronary artery disease, but multiscale anisotropy analysis discriminated between these populations. Our mass spectrometry analysis identified a cohort of proteins that distinguish between adipose depots, and are also associated with the presence or absence of coronary artery disease.

Strong decline in grasshopper abundance over 20 years without major land-use changes: Is soil drying one of the drivers?

Strong declines in insect numbers have been described for different taxa and regions. These observations are of great concern such that broad scientific and public attention has been raised. Among other urgencies, the need for long-term insect data has been identified. Here, we present data on grasshopper (Caelifera) abundances recorded between 1992 and 2011 at over 600 sites in north-western Switzerland. While vegetation type, often semi-natural grasslands, had remained largely constant, total grasshopper abundance declined by around 50 % (while many other taxa showed much less decline). Numbers in July remained relatively stable until about 2003 but then declined similar to the declines seen in August–October already before. Greatest losses were observed for drier habitats and steeper slopes, suggesting that soil drying might be an important factor for the decline. Second, more nutrient-rich habitats suffered greater losses; possible reasons for this include small-scale vegetation changes in these habitats e.g. due to atmospheric nitrogen deposition, or isolation of sites. Other than abundance, species richness decreased much less, illustrating that important ecological changes may be strongly underestimated when only species lists are available. The strong declines at our sites, which often are in an agri-environmental scheme, is alarming. Apart from being yet another call to fight climate change, our results also point to the urgent need to reduce atmospheric nitrogen deposition and to continue extensive farming, but also to adapt it in preparation of expected effects of climate change, with the aim to favour a divers, ecologically robust insect community.

Neutral atomic and molecular gas dynamics in the nearby spiral galaxies NGC 1512, NGC 4535, and NGC 7496

Neutral atomic gas (H I) effectively traces galactic dynamics across mid to large galactocentric radii. However, its limitations in observing small-scale changes within the central few kiloparsecs, coupled with the often observed H I deficit in galactic centers, necessitates the use of molecular gas emission as a preferred tracer in these regions. Understanding the dynamics of both neutral atomic and molecular gas is crucial for a more complete understanding of how galaxies evolve, funnel gas from the outer disk into their central parts, and eventually form stars. In this work we aim to quantify the dynamics of both, the neutral atomic and molecular gas, in the nearby spiral galaxies NGC 1512, NGC 4535, and NGC 7496 using new MeerKAT H I observations together with ALMA CO (2-1) observations from the PHANGS collaboration. We use the analysis tool 3DBarolo to fit tilted ring models to the H I and CO observations. A combined approach of using the H I to constrain the true disk orientation parameters before applying these to the CO datasets is tested. This paper sets expectations for the results of the upcoming high-resolution H I coverage of many galaxies in the PHANGS-ALMA sample using MeerKAT or VLA, to establish a robust methodology for characterizing galaxy orientations and deriving dynamics from combing new H I with existing CO data.

Lack of Small-Scale Changes in Breeding Birds after a Fire: Does the Resilience of Cork Oaks Favor Rapid Recolonization in Suburban Wood Patches?

Forest fires are disturbance events that can impact biological assemblages at multiple scales. In this study, the structures of breeding bird communities in cork oak patches located in an agro-mosaic suburban landscape of central Italy (Rome) were compared at the local scale with a fine-grained mapping method before (2018) and after (2023) a fire event occurred in July 2022. The analyses did not reveal any significant changes in the density of territorial pairs or in the diversity metrics, both univariate (Shannon–Wiener index, evenness, Margalef normalized richness) and bivariate (Whittaker and k-dominance plots, abundance/biomass curves) of diversity. Even when the guilds of strictly forest-related species were compared, no differences emerged before and after the fire. This counterintuitive phenomenon may be due to the characteristics of the dominant tree, the cork oak (Quercus suber), a sclerophilous tree that is very resilient to fires and able to recover foliage in the following spring season, thus allowing rapid bird recolonization. However, other small-scale phenomena (e.g., the ‘crowding effect’ and local dispersal of territorial pairs from remnant wood patches not affected by fire) may explain this lack of change in breeding bird density and diversity. Further studies should be carried out at larger spatial and temporal scales and at different levels of fire frequency and intensity to confirm these responses at the guild/community level in suburban cork oak wood patches.

Outcomes of co-designed communities of practice that support members to address public health issues.

Communities of practice are commonly used to support members in responding to public health issues. This study evaluated the outcomes of five co-designed communities of practice to determine if members' expectations were met, if knowledge sharing between members extended to knowledge translation, and if that supported members in addressing public health issues. Data were collected through an initial needs assessment, observations were made during community of practice sessions over 1 year, and qualitative interviews were conducted at the end of that year. The findings provided evidence that members' expectations were met, knowledge sharing took place within the communities of practice, and personal benefits gained supported members in advancing knowledge sharing with other members to knowledge translation outside their community of practice. Results demonstrate three outcomes of knowledge translation for members: disseminating knowledge to others, applying knowledge to make small-scale changes in practice and leveraging the knowledge to expand its reach beyond members' organizations. While the scale and speed of expanding outcomes were below initial expectations as indicated in the initial needs assessments, members remained optimistic about achieving larger-scale impacts in the future. This study showed that communities of practice achieve gradual progress rather than quick wins. Co-design supports the facilitators in meeting members' needs, which can positively contribute to members sharing knowledge and translating that knowledge to support their practice to address public health issues.

Weser Old Frisian Dative Plural -on: A West Germanic Isogloss?

Abstract The Weser Old Frisian a-stem dative plural ending -on is unusual, since the other Old Frisian dialects reflect -um. This article discusses whether -on is the result of affix borrowing from Old Saxon or the result of a regular sound change, guided by typological and dialectological considerations. The truth appears to lie somewhere in the middle: The ending -on is likely the result of a small-scale sound change that only affected the dialects ancestral to Weser Old Frisian, Old Saxon, and Old Dutch.

Incorporation of RCM-simulated spatial details into climate change projections derived from global climate models

Regional climate models (RCMs) exhibit greater potential than global models (GCMs) in capturing geographical details of climate change arising from orography and land–water distribution, but dynamical downscalings are only available for a limited number of GCMs. The full GCM ensembles are much more representative. Furthermore, the current EURO-CORDEX RCM runs most likely underestimate future warming. Thus, neither GCMs nor RCMs as such constitute an ideal tool for preparing reliable spatially detailed climate projections. This study introduces an easy-to-use GCM-RCM hybrid method that takes advantage of the best properties of both model categories. The large-scale response is adopted from GCM simulations, but the pattern is enriched with RCM-simulated details. For temperature projections, the procedure resembles the conventional pattern-scaling technique. However, the spatial averages of temperature change used for scaling are calculated over an area surrounding each grid point, either by giving an equal weight to the entire area or by taking into account the land–sea distribution. For precipitation, a linearised version of the method has been formulated. The method is demonstrated by integrating spatial details from 12 EURO-CORDEX RCM simulations with the CMIP6 multi-GCM mean projection. The resulting temperature responses include RCM-generated spatial details of up to ∼\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\sim$$\\end{document} 1 ∘\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^\\circ$$\\end{document}C while effectively correcting the general tendency of RCMs to underestimate warming in Europe. For precipitation, geographical details originating from the different CORDEX runs tend to diverge, resulting in a low signal-to-noise ratio. This probably reflects the substantial impact of internal variability on small-scale changes in precipitation.

Valuing wildlife sightings at the species-wide and individual animal levels: an approach and application to bear viewing in Yellowstone National Park

ABSTRACT Wildlife viewing is a popular recreation activity in parks and protected areas around the world, yet information on the nonmarket value that visitors derive from viewing specific species, and how that value is affected by small-scale population changes, is lacking. We devised an approach to fill the gap. First, we applied the travel cost method to obtain the value of a wildlife viewing trip. Next, we estimated a value per animal sighting, which we aggregated by the number of visitors who experienced and valued a sighting. Finally, we incorporated the probability of viewing an animal to determine an individual animal’s contribution to sighting value, which varies by species type, visibility, and seasonality. We examined bear viewing in Yellowstone National Park. For grizzly and black bears, respectively, per-sighting values are $16 and $14, aggregate annual sighting values are $6.9 and $9.7 million, and annual per-bear viewing values are $46,000 and $15,000.

Microtopography effects on pedogenesis in the mudstone-derived soils of the hilly mountainous regions

Topography is a critical factor that determines the characteristics of regional soil formation. Small-scale topographic changes are referred to microtopographies. In hilly mountainous regions, the redistribution of water and soil materials caused by microtopography is the main factor affecting the spatial heterogeneity of soil and the utilization of land resources. In this study, the influence of microtopography on pedogenesis was investigated using soil samples formed from mudstones with lacustrine facies deposition in the middle of the Sichuan Basin. Soil profiles were sampled along the slopes at the summit, shoulder, backslope, footslope, and toeslope positions. The morphological, physicochemical, and geochemical attributes of profiles were analyzed. The results showed that from the summit to the toeslope, soil thickness increased significantly and profile configuration changed from A–C to A–B–C. The total contents of Ca and Na decreased at the summit, backslope, and footslope, while the total contents of Al, Fe and Mg showed an opposite trend. On the summit and shoulder of the hillslope, weathered materials were transported away by gravity and surface erosion, exposing new rocks. As a result, soil development in these areas was relatively weak. In flat areas such as the footslope and toeslope with sufficient water conditions, the addition of weathered components and the prolonged contact between water, soil, and sediment led to further chemical weathering, resulting in highly developed characteristics. Microtopography may influence physicochemical properties, chemical weathering, and redistribution of water and materials, causing variations in pedogenic characteristics at different slope positions.

Autonomous driving in traffic with end-to-end vision-based deep learning

This paper presents a shallow end-to-end vision-based deep learning approach for autonomous vehicle driving in traffic scenarios. The primary objectives include lane keeping and maintaining a safe distance from preceding vehicles. This study leverages an imitation learning approach, creating a supervised dataset for robot control from expert agent demonstrations using the state-of-the-art Carla simulator in different traffic conditions. This dataset encompasses three different versions complementary to each other and we have made it publicly available along with the rest of the materials. The PilotNet neural model is utilized in two variants: the first one with complementary outputs for brake and throttle control commands along with dropout; the second one incorporates these improvements and adds the vehicle speed. Both models have been trained with the aforementioned dataset. The experimental results demonstrate that the models, despite their simplicity and shallow architecture, including only small-scale changes, successfully drive in traffic conditions without sacrificing performance in free-road environments, broadening their area of application widely. Additionally, the second model adeptly maintains a safe distance from leading cars and exhibits satisfactory generalization capabilities to diverse vehicle types. A new evaluation metric to measure the distance to the front vehicle has been created and added to Behavior Metrics; an open-source autonomous driving assessment tool built on CARLA that performs experimental validations of autonomous driving solutions.

Temporal and spatial variations of terrestrial water storage in the northeastern Tibetan Plateau retrieved by GNSS observations

The variation of solid Earth's hydrologic loading could cause the elastic vertical deformation of the crust, and the Global Navigation Satellite System (GNSS) could effectively monitor the vertical displacement of surface loads. However, the widely used Green's function method does not work well in areas where GNSS sites are sparse. Here, the vertical displacement time series of GNSS stations and the Slepian basis function method have been applied to convert displacement signals into spatial spectrum signals. The elastic mass load theory is used to study the changes in terrestrial water storage on the Northeastern Tibetan Plateau (NETP). The temporal and spatial characteristics of seasonal water changes are well-represented by the GNSS, the Gravity Recovery and Climate Experiment (GRACE), and the Global Land Data Assimilation System (GLDAS). Several data points suggest that the change in water storage shows a gradual increase from the northeast to the southwest. The greatest annual amplitude of water storage retrieved by GNSS is ∼159 mm, which is greater than the ∼47 mm and ∼44 mm obtained by GRACE and GLDAS. These results demonstrate that GNSS is capable of capturing small-scale hydrological changes in this region, whereas GRACE and GLDAS data tend to underestimate seasonal variations in water storage. We also used GNSS to describe the hydrological drought conditions in NETP, showing that GNSS could be used as an independent method to characterize hydrological drought events. The findings suggest it could observe water storage with high spatial and temporal resolution and aid in comprehending regional hydrological trends with a sparse GNSS station network.

The Danger of the Interpretation of Facts: Legal Uncertainty in the Spanish Saga Cases

Enhancing legal certainty is one of the main values that are sought in the investor–state dispute settlement system. The importance of legal certainty is strengthened in the case of renewable energy investments, which are in the global public interest, long-term and capital-intensive up-front. The first part of the paper presents the importance of legal certainty in investment arbitration in general, its limits and its importance in the context of the green energy transition. In addition, it addresses the special features of renewable energy investments. The second part of the paper analyses from the perspective of legal certainty the Spanish renewable energy cases initiated under the Energy Charter Treaty (ECT), which deal with similar factual and legal issues. In this respect, the paper presents the varying weight tribunals gave to the important facts that led them further to conclude whether Spain breached the fair and equitable treatment standard, and if so, whether the investor was entitled to full compensation or a reasonable rate of return. In addition, it presents different approaches to perceiving the stability provision of Article 10 (1) of the ECT. The paper concludes that it remains uncertain to what extent RE investors will be protected under the ECT’s stability condition in the case of fundamental or small-scale changes. Although one group of arbitrators may argue that the fundamental change triggers per se a breach of a stability condition, others may argue that for the breach to be established, the host state’s measures must be arbitrary, unreasonable or discriminatory. Moreover, the threat to legal certainty might not only be the vague provisions of the ECT but also the significant discretion tribunals have towards the interpretation of facts, leading to different outcomes. Indeed, it is at the discretion of arbitrators to consider whether the timing of investment, presence of evidence indicating possible regulatory changes, and the reasonable rate of return prescribed in Spain’s domestic law will be relevant or irrelevant.

Multiscale insights into electric field orientation effects on piezoelectric strain and crystallography in P(VDF–TrFE) and P(VDF–TrFE–CTFE) fibers

This research primarily focuses on the effect of changing electric field directions on the crystal structure of piezoelectric fibers, notably, P(VDF–TrFE) and P(VDF–TrFE–CTFE). The study also explores the deformation mechanisms of fibers at micro- and nanoscales. A significant aspect of the research involves the application of parallel and perpendicular electric fields and observation of their impact on fiber properties. In situ wide-angle X-ray diffraction (WAXD) studies are crucial for determining the nanoscale properties when the electric field orientations change. The results show that the direction of the electric field significantly affects the sign (positive or negative) of the dipole vector within the β-crystal lattice structure of the fibers. This can be attributed to the rotation of dipole vectors in response to the electric field–fiber alignment angle. Furthermore, the research identifies the crystal plane (201,111)β as exhibiting the highest magnitude of piezoelectric response strain in the β phase. The study also employs scanning electron microscopy and digital image correlation (DIC) to reveal the material's morphology and to assess fiber strain distribution at the micrometer scale under different voltages. DIC results particularly highlight that stress concentration leads to the deformation of fibers into voids, which are spaces between fibers created by electrospinning. This work comprehensively elucidates how deformation works in piezoelectric polymers by connecting large-scale changes observed in fibers through DIC and small-scale changes observed in WAXD studies presenting the piezoelectric strain responses at the crystal plane.

Sea Surface Height Wavenumber Spectrum from Airborne Interferometric Radar Altimeter

The proposed “Guanlan” ocean science satellite, led by China’s Laoshan Laboratory, includes an interferometric radar altimeter (IRA) as a key payload. As an integral part of its development, an airborne IRA experiment was conducted on 6 November 2021, with a flight path of approximately 90 km in the South China Sea. This study investigates the IRA’s ability to observe ocean sea surface height (SSH) across scales ranging from meters to mesoscale. The sea surface height anomaly (SSHA) of the IRA is aligned with the SSHA of the AVISO at scales greater than 30 km, but also demonstrates the ability to capture small-scale SSHA changes in two dimensions. We analyzed wavenumber spectra of SSHA obtained from the airborne IRA, ICESat-2, and SARAL/AltiKa satellite for this region. The results show a good agreement in power spectral density (PSD) levels between ICESat-2, SARAL/AltiKa and IRA at scales larger than 30 km. Within the submesoscale range of 1–10 km, the IRA SSHA spectrum exhibits a distinctly negative slope and the lowest energy level. The minimum PSD level of the IRA fell in the range of 10−4–10−3 m2/cycle/km, at scales around 1 km, which is more than an order of magnitude lower than that of ICESat-2, forming a spectral gap that is in agreement with the theoretical expectation. Furthermore, IRA-derived wave direction and significant wave height matched well with the MFWAM wave data. The results of this study underscore the considerable potential of airborne IRA in capturing SSHA across a range of scales, from oceanic waves to submesoscale.

Small-scale land-use change effects on breeding success in a desert-living social bird

Abstract Human villages in deserts can provide resources in an otherwise stark environment, potentially buffering against extreme environmental conditions. It is thus expected that breeding within these villages would result in higher fitness. However, choosing to raise offspring in these resource-rich environments may have unintended negative consequences. Here, we studied the breeding success of a cooperative breeding bird nesting in habitats with different levels of human disturbance—the Arabian babbler (Argya squamiceps), in the Negev desert of Israel. We recorded 42 breeding attempts from 15 groups between March and July 2022. We examined overall breeding success, brood size, and causes of nest failure. When nestlings were 6 days old, we also calculated daily change in body mass and adult provisioning rate. We found that despite higher resource abundance in villages, proximity to villages did not affect provisioning rate, and nestlings gained less mass at higher temperatures for all nests. Currently, there is no evidence that human villages are providing oases of resources for nesting babblers. Further, various conservation interventions (e.g., encouraging residents to keep cats indoors) could improve babblers’ overall fitness. Ultimately, we highlight how, for some desert specialists, additional resources provided by humans may not do enough to counter potential negative effects.

Habitat changes explain shifts in bird community composition in abandoned military training areas: Lessons for conservation

Military training areas are important biodiversity refuges and may serve as viable components of regional conservation networks, mainly due to the blocking of ecological succession by the disturbance regime creating a heterogeneous open habitat mosaic hosting many threatened species. However, European armies have undergone downsizing over the past decades and numerous military training areas have been abandoned. The assessment of the consequences of this abandonment for biodiversity would show us whether these abandoned areas still provide conservation benefits. For this purpose, we carried out bird surveys in 30 abandoned military training areas in Czechia. The surveys were performed in two periods (2009 and 2020–2021) to track small-scale changes in land cover and bird abundance after the areas were abandoned in the 1990s. We tested (i) whether changes in bird abundance were related to land cover changes and (ii) whether the observed bird species’ responses to the land cover changes can be explained by species-specific characteristics. Multivariate spatial analyses uncovered significant shifts in land cover composition towards a higher representation of dense shrub, forest and built-up areas at the expense of open areas represented by grassland and sparse shrub. These land cover changes explained a small but significant part of bird abundance variation across the areas. Correspondingly, species benefiting from these land cover changes were associated with dense scrub or forest, such as the Common Chiffchaff, Willow Warbler, or Eurasian Blackcap, whereas species suffering from these changes were associated with grassland, such as the European Stonechat and Eurasian Skylark. Phylogenetically informed interspecific analysis aiming to explain changes in bird abundance between periods confirmed that population declines were linked to open habitat preference, while population increases were linked to the preference for dense shrub and forest. In addition, we found that protected species increased their abundance, most likely due to the existence of conservation management that kept their habitats available. These patterns indicate that military training areas transform toward later successional stages after their abandonment with corresponding changes in bird community composition. However, these changes may not necessarily be negative provided that species of conservation concern enjoy the support of conservation management.

Predator-prey interactions in a coastal setting: Linking crab feeding rates to small scale distribution of clams

A coastal predator-prey system, juvenile green crabs (Carcinus maenas) preying upon juvenile hard clams (Mercenaria mercenaria), was used to explore the link between crab predation rates and clam density and small-scale distribution patterns. The channel working area of a racetrack flume was adapted to form a sedimentary arena in a flowing seawater system (5 cm s−1) to assess crab predation rates in relation to clam density and distribution patterns (clams clustered in one patch vs two nearby vs two farther apart). The trials detected significant differences in relation to clam initial density and distribution with strong (∼50%) declines in clam mortality levels among spatial arrangements (one patch > two nearby > two farther apart). Feeding of clams was associated with the time taken by crabs to handle the first clam (first patch), and the frequency of three distinct types of crab behavior (eating, resting, and searching). Altogether these results suggest that small-scale changes in number and distribution of juvenile clams matter and may have unexpectedly strong effects on the outcome of predator-prey interactions.

Non-extensive (Tsallis) q-statistics and auroral glow

It is well-known that the auroral region of the magnetosphere–ionosphere interaction is an open, nonlinear dissipative system far from the equilibrium state. It is in this region that auroras are regularly observed, demonstrating not only a wide variety of dynamic forms but also a wide range of temporal and spatial scales. Due to the memory effects and fractal properties of auroral plasma, as well as strong correlations between its individual parts, the dynamics of the high-latitude system are primarily determined by long-range electromagnetic forces. Therefore, it is expected that non-additive and non-extensive thermodynamic principles may characterize their macroscopic behavior. In the presented study, it is shown that pulsating auroras exhibit non-extensive properties and can be described by q-statistics. The correlation of the parameter q with traditional indicators of nonlinear dynamics, such as the flatness coefficient, standard deviation, and scaling index, has been investigated. Small-scale changes are superimposed on large-scale processes characterized by a low correlation dimension, and this leads to an increase in the correlation dimension during geomagnetic activity, which approximately coincides with increased values of q. It is concluded that the q-statistics (Tsallis distribution) can be used to analyze optical phenomena in the auroral region.