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Classifying accuracy of fin whale range estimates from single seismic sensors
No full textOcean-bottom seismometers (OBSs) are used increasingly often to track baleen whale signals, employing single-station ranging techniques such as the three-component (3C) method. By using the orientation of ground motion from OBS components, the 3C method provides robust range estimates of direct-path signals within a validity range that relates to instrument depth. Consequently, the method requires a classification process to determine whether a signal falls within the validity range. Fin whale tracks, composed of 20-Hz notes from six locations, were used to develop and evaluate three classification models: decision trees (DTs), generalized additive models, and neural networks. Models were trained using different data combinations and incorporated a comprehensive set of variables related to channel amplitude, signal quality, polarization, and estimated signal angles. The DT achieved the highest performance, reaching an accuracy of 0.94 on the test data. Key variables for predicting the validity of the 3C ranges included the difference between observed horizontal-to-vertical amplitude ratios and its theoretical value, polarization metrics, and the amplitude of one horizontally oriented OBS component (Y-channel). The resulting framework contributes to improving the utility of seismic data for biological studies, which are critical for marine mammal monitoring and conservation strategies
Natural warning signals unexpectedly shape human metamemory ratings but not image recognition success
No full textAlthough the bold warning signals of prey (known as aposematic) have been shown to facilitate predator learning through repeated encounters, it remains unclear to what extent their visual patterns and colours support memory retention. Here, we tested whether aposematic species appear more memorable to human observers, and whether they have an intrinsic advantage in being recognised from memory—even after a single exposure. Observers viewed images of aposematic and non-aposematic butterflies and moths, judged how likely they were to remember each one (metamemory rating), and later completed a test distinguishing previously seen species from novel ones (recognition memory). While aposematic patterns elicited higher metamemory ratings upon first sight, we found no evidence that they were more likely to be recognised when seen again. Despite this apparent metacognitive failure, for aposematic species the observers tend to remember and forget the same images as one another. This suggests that these images exhibit ‘memorability’, an intrinsic property of an image that allows one to predict how well images can be remembered. These findings raise the possibility that an effective visual warning may hinge less on recognition of a previously seen signal, and more on perceptual processes at play when it is first encountered
Degradation of fish food webs in the Anthropocene
No full textGlobal change reshapes biodiversity through shifts in species composition, richness, and body size. How these shifts combine to alter higher-level ecological processes within food webs can have important implications for entire ecosystems. However, the strength and direction of these shifts will depend on combinations of ways that species and trait compositions change through time. We combine long-term data from ~15,000 freshwater and marine fish communities (1949-2019) with information about their size, diets, and trophic status to evaluate how food webs change through time at local spatial scale. We found that selective species turnover driven by body size reductions is associated with widespread alteration to fish food web topology and function, including increased connectance and generalism, leading to higher predation pressure and increased prey vulnerability. Food webs were also less modular. These changes extend across food web trophic structures, causing a cascading shift in the proportion of species across trophic levels. Our study highlights complex biodiversity responses to confluent changes across multiple facets.</p
The effect of differing levels of intrasexual and intersexual selection on survival and reproduction under a heatwave
No full textHeatwaves are set to become more common due to climate change, and the potential of heatwaves to damage a species' populations is becoming more apparent. One way heatwaves can affect reproduction is by changing the dynamics of precopulatory mating behaviours, which can detrimentally impact individuals' survival and reproductive success. However, little work has been done to investigate how different levels of intrasexual and intersexual selection in precopulatory behaviours, such as male–male competition or female-mate choice, modulate fitness responses to heatwave. Here we investigate how differing levels of male competition and female choice impact survival and reproductive success when a heatwave event occurs, using cool-adapted Scottish populations of the burying beetle Nicrophorus vespilloides as a model system. We implemented three treatments for precopulatory conditions: monogamy (one male, one female, no male–male competition), polyandry with male competition (one female, two males, where males and females could freely interact), and polyandry with low male competition (one female, two males, where males could not interact with each other or the female freely). We then subjected the beetles to a heatwave event (3 days at 25°C) at the time of mating. We found that reproductive fitness decreased under a heatwave in the polyandry/low male competition treatment, compared to both the monogamy and the male competition treatments. Our results indicate that differing levels of intrasexual and intersexual selection can moderate the detrimental effects of heatwaves in wild species.</p
Geomagnetic night vision:a data-driven approach to study geomagnetic navigation in a migratory bird
No full textGeomagnetic navigation during long-distant bird migration is widely debated and it remains unclear which properties of the geomagnetic field birds use and how information might be used. This study is the first use of high-resolution GPS tracking data with co-located and contemporaneous satellite geomagnetic data applied in a step-selection analysis to objectively model geomagnetic navigational strategies in a data-driven approach. We use a day and night-time migrant, the Eurasian Curlew (Numenius arquata) as a model species. Additionally, we test the effect of additional factors (day vs night, spring vs autumn) which have been suggested in the literature or tested indirectly with behavioural experiments. To our knowledge, this study is the first empirical evidence for the effect of night-time and the effect of the angle between the two navigational cues involved (intensity and inclination), on geomagnetic navigation. Our data support previous findings that taxis cue use based on the geomagnetic field intensity showed the best model fit (adj. R² ≈ 0.82 at night) suggesting this as a potential geomagnetic cue use mechanism for animals. The use of a data-driven and step-selection analysis has important implications for future studies of navigational cue use. This can be used for studying interaction effects of different navigation mechanisms, the effect of environmental factors like wind, and the comparison of navigation mechanisms between different species and geographical areas
From earth and water to Spandarmaz and Anahita:women as archetypal agents of emancipation and sovereignty in Iranian romances and folktales
No full textElection cycles and systemic risk
No full textWe examine whether election periods are associated with systemic risk. Our sample comprises banks from 22 OECD economies over the period 2000 to 2023, and covers 147 national elections. The findings indicate that systemic risk increases during election and post-election periods, while it is reduced in the pre-election period in the case of end-of-term elections. More specifically, the year in which elections occur is associated with a 3.57% higher systemic risk relative to the overall average. The results can be attributed to the suppression of negative information and expansionary fiscal policies in the period before elections. Notably, the impact is more pronounced for snap elections and when the incumbent government is not re-elected. The effect is also stronger in common-law countries, where more market-based financial systems transmit political shocks more rapidly than in civil-law jurisdictions. In addition, we find that macroprudential policies, strong economic growth, trust in the current government and banks’ financial health can partially mitigate the impact of elections on systemic risk. Finally, to alleviate endogeneity concerns, we employ two instrumental variables, namely, term limits and an election uncertainty index based on Google Trends and the results hold and confirm our previous findings, further validating the robustness of our analysis
The probability of generating a uniserial group
No full textFamously, every finite simple group can be generated by a pair of elements. Moreover, Liebeck and Shalev (1995) proved that the probability that a pair of elements generate tends to as . More generally, work of Lucchini and Menegazzo (1997) implies that can be generated by a pair of elements whenever has a unique chief series. In this paper, we generalize the theorem of Liebeck and Shalev by proving that if has a unique chief series and the unique simple quotient of is , then the probability that a pair of elements generate tends to as . As a consequence of our main theorem, for any profinite group where the open normal subgroups form a chain, the probability that a pair of elements topologically generate is positive. Along the way, we establish results on the maximal subgroup zeta function of groups with a unique minimal normal subgroup
Sibling sub-Neptunes around sibling M dwarfs:TOI-521 and TOI-912
No full textContext. Sub-Neptunes are absent in the Solar System, yet they are the most common category of planets found in our Galaxy. This kind of planet challenges the internal structure models, prompts investigations into its formation and evolution, and pushes atmospheric characterisation studies to break the degeneracy in their inner composition.Aims. We report here the discovery and characterisation of new sub-Neptunes orbiting two similar M dwarfs, TOI-521 (Teff = 3544 ± 100 K, V = 14.7 mag) and TOI-912 (Teff = 3572 ± 100 K, V = 12.7 mag). Each star hosts a transiting planetary candidate identified by TESS and is part of the THIRSTEE follow-up programme, which aims to understand the sub-Neptune population through in-depth and precise characterisation studies on a population level.Methods. We analysed TESS light curves, ground-based photometry, and high-precision ESPRESSO, HARPS, and IRD radial velocities to confirm the planetary nature of both candidates, infer the precise orbital and physical parameters of the planets, and investigate the presence of additional planets in the systems.Results. The two stars host nearly identical planets in terms of mass and radius. TOI-521 hosts a transiting sub-Neptune in a 1.5-day orbit with radius and mass of Rb = 1.98 ± 0.14 R⊕ and Mb = 5.3 ± 1.0 M⊕, respectively. Moreover, we identified an additional candidate at 20.3 days, with a minimum mass of Mp sin i = 10.7−2.4+2.5 M⊕, currently not detected as transiting in our photometric dataset. Similarly, the planet orbiting TOI-912 is a 4.7-d sub-Neptune with Rb = 1.93 ± 0.13 R⊕ and Mb = 5.1 ± 0.5 M⊕. Interestingly, TOI-912 b likely possesses an unusually high eccentricity (e = 0.58 ± 0.02) and is probably undergoing strong tidal dissipation. If such eccentricity were confirmed, it would make TOI-912 b one of the most eccentric sub-Neptunes known to date. TOI-521 b and TOI-912 b have very similar densities (~4 g cm−3), and they lie in the degenerate region of the mass-radius diagram where different compositions are plausible, including a volatile-rich composition, or a rocky core surrounded by a H-He envelope. When compared to the other THIRSTEE M-dwarf targets, our sample supports the division of sub-Neptunes into two distinct populations divided by a density gap. Both planets are interesting targets for atmospheric follow-up in the context of understanding the temperature-atmospheric feature trend that starts to emerge thanks to JWST observations
Bahram Beyzaie’s dramatic and cinematic oeuvre
No full textIn this entry, I trace the trajectory of Bahrām Bayzā’ī’s creative impulse and examine his oeuvre to offer an analytical overview of his aesthetic and thematic concerns and innovations. Before embarking on my chronological overview, however, I need to clarify a few general points. In my writing, I pay attention to a number of key ideas and practices which are central to Bayzā’ī’s vision: (1) modernity, modernization, and democracy, (2) marginalization, trauma, and creativity, (3) outsider gaze, epistemic privilege, and epistemic authority, (4) transgressive and emancipatory framing and reframing, (5) redistributing the sensible by introducing new ways of seeing, doing, and understanding, (6) modalities and transformations of personal and collective identities, (7) desire for belonging, recognition, and self-recognition as incentives for change, (8) constructive curiosity, worldliness, and intellectuality, (9) citizenship and leadership, (10) gender relations and hegemonic masculinity and femininity, (11) totalitarianism, patriarchy, and power, (12) sociopolitical and religious surveillance, (13) reformulation of Iranian and non-Iranian dramatic and cinematic forms to create new artistic forms, and (14) yoking these reformulated forms to particular situations to construct his emancipatory aesthetics
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