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The late pliocene to early pleistocene lomekwi faunas, west Turkana, Kenya: systematics, paleoecology, and biochronology
No full textWe describe here the vertebrate fauna collected by the West Turkana Paleo Project at Lomekwi, a site best known for yielding the holotype of Kenyanthropus platyops and Lomekwian stone tools, and consisting of several collecting areas providing fossil samples ranging in age from about 3.6 to 2.2 Ma. Analysis of the newly recovered material, alongside a thorough revision of earlier collections, has led to the identification of 85 vertebrate taxa, which provide biochronological indications that help refine the site's chronology and shed light on the paleoenvironmental conditions prevailing during a critical period of early hominin diversification. The newly described fauna illustrates that during the time of Kenyanthropus, hominins shared their landscapes with a rich assemblage of vertebrates, including abundant megaherbivores, some 28 species of artiodactyls, diverse large and medium-size carnivores, and giant crocodiles as apex predators in the lakes and rivers of the Turkana region in the Pliocene. Among primates, the recurring association of Theropithecus with hominins is found at Lomekwi as it is elsewhere. Paleoenvironmental proxies from the Turkana region emphasize the complex and dynamic nature of the habitats that supported this rich biodiversity.BCS 155199
Towards a formation model of the Neanderthal symbolic accumulation of herbivore crania: spatial patterns shaped by rockfall dynamics in level 3 of des-cubierta cave (Lozoya valley, Madrid, Spain)
No full textUnderstanding formation processes is crucial for interpreting sites with complex sedimentary histories and exceptional archaeological records, such as Level 3 of Des-Cubierta Cave. This Middle Paleolithic unit contains an assemblage of anthropically modified ungulate horned crania, Mousterian lithics, and evidence of fire use, all preserved in a clast-supported gravel deposit shaped by successive rockfalls. This study integrates geostatistical analyses with traditional spatial and taphonomic methods to examine the cone-shaped sedimentary structure that dominates the level and its influence on the spatial distribution and preservation of archaeological materials. The results reveal distinct spatial patterns for geological and archaeological materials, indicating separate formation dynamics. Size-based spatial analyses of boulders characterize the morphology of the conical structure, highlighting size sorting and intensity variations that may indicate sedimentary hiatuses. Bone refitting analysis suggests limited post-depositional movement, with material distribution shaped by the conical sedimentary structure and karst gallery morphology. Variability in crania preservation correlates with proximity to the cone's apex and elevation, with better-preserved specimens in central areas and more fragmented remains in zones affected by erosive and edaphic processes. These findings underscore the value of integrating geostatistical and traditional archaeological approaches to advance interpretations of spatial and temporal patterns in karst environments and provide a methodological approach for examining sites with similar sedimentary histories. Moreover, the results support the interpretation of a recurrent, culturally motivated Neanderthal behaviour centred on the deliberate accumulation of large ungulate crania, pointing to a symbolic dimension in these practices.H2019/HUM-5840, PHS-2024/PH-HUM-469, 10115220
Afar fossil shows broad distribution and versatility of paranthropus
No full textThe Afar depression in northeastern Ethiopia contains a rich palaeontological and archaeological record, which documents 6 million years of human evolution. Abundant faunal evidence links evolutionary patterns with palaeoenvironmental change as a principal underlying force1 . Many of the earlier hominin taxa recognized today are found in the Afar, but Paranthropus has been conspicuously absent from the region. Here we report on the discovery, in the Mille-Logya research area, of a partial mandible that we attribute to Paranthropus, dated to between 2.5 and 2.9 million years ago and found in a well-understood chronological and faunal context. The find is among the oldest fossils attributable to Paranthropus and indicates that this genus, from its earliest known appearance, had a greater geographic distribution than previously documented2 . Often seen as a dietary specialist feeding on tough food, the range of diverse habitats with which eastern African Paranthropus can now be associated shows that this suggested adaptive niche did not restrict its ability to disperse as widely as species of Australopithecus and early Homo. The discovery of Paranthropus in the Afar emphasizes how little is known about hominin evolution in eastern Africa during the crucial period between 3 and 2.5 million years ago, when this genus and the Homo lineage presumably emerged
Gravitational waves from two scalar fields unifying the dark sector with inflation
No full textWe investigate the gravitational wave background predicted by a two-scalar-field cosmological model that aims to unify primordial inflation with the dark sector, namely, late-time dark energy and dark matter, in a single and self-consistent theoretical framework. The model is constructed from an action inspired by several extensions of general relativity and string-inspired scenarios and features a nonminimal interaction between the two scalar fields, while both remain minimally coupled to gravity. In this context, we derive the gravitational wave energy spectrum over wavelengths ranging from today’s Hubble horizon to those at the end of inflation. We employ the continuous Bogoliubov coefficient formalism, originally introduced to describe particle creation in an expanding Universe, in analogy to the well-established mechanism of gravitational particle production and, in particular, generalized to gravitons. Using this method, which enables an accurate description of graviton creation across all cosmological epochs, we find that inflation provides the dominant gravitational wave contribution, while subdominant features arise at the inflationradiation, radiation-matter, and matter-dark energy transitions, i.e., epochs naturally encoded inside our scalar field picture. The resulting energy density spectrum is thus compared with the sensitivity curves of the planned next-generation ground- and space-based gravitational wave observatories. The comparison identifies frequency bands where the predicted signal could be probed, providing those windows associated with potentially detectable signals, bounded by our analyses. Consequences of our recipe are thus compared with numerical outcomes and the corresponding physical properties are discussed in detail.UID/04106/2025; UID/PRR/04106/202
Resilient wireless sensor actor networks through multi-objective self-adaptation
No full textWireless Sensor Actor Networks (WSAN) are a key enabler of Internet of Things applications that demand timely and reliable data exchange under dynamic conditions. Among the various domains that benefit from these networks, precision agriculture stands out, demanding adaptive strategies for effective monitoring and control. This study proposes a reinforcement learning approach that leverages the Operationalization construct of the Self-Orchestrated Web of Things (SOrWoT) framework to enhance the adaptability of Things’ internal operations. A problem is formulated as a Markov Decision Process, and a Deep Q-Learning agent is trained in a custom simulation environment to identify the most suitable Operationalizations for optimizing data accuracy and latency, under changing conditions and communication failures. The results show that during normal operation the agent favored parallel sensor data averaging to minimize read error, but after an actor failure and the consequent increase in sensor-to-actor distances, it adapted by prioritizing latency through faster Operationalization choices. Sensitivity analyses further confirmed the agent’s ability to adjust policies in response to partial failures, and to shifts in the relative importance of latency versus accuracy. These findings demonstrate that reinforcement learning can autonomously optimize WSAN performance, contributing to resilient and self-adaptive systems.UI/BD/152864/202
Impact of persistently high sea surface temperatures on the rhizobiomes of Zostera marina in a Baltic Sea benthocosms
No full textbiodiversity. The Baltic Sea, warming faster than other seas, is a good model to study the impact of increasing sea surface temperatures. Zostera marina, a key player in the Baltic ecosystem, faces susceptibility to disturbances, especially under chronic high temperatures. Despite the increasing number of studies on the impact of global warming on seagrasses, little attention has been paid to the role of the holobiont. Using an outdoor benthocosm to replicate near-natural conditions, this study explores the repercussions of persistent warming on the microbiome of Z. marina and its implications for holobiont function. Results show that both seasonal warming and chronic warming, impact Z. marina roots and sediment microbiome. Compared to roots, sediments demonstrate higher diversity and stability throughout the study, but temperature effects manifest earlier in both compartments, possibly linked to premature Z. marina die-offs under chronic warming. Shifts in microbial composition, such as an increase in organic matter-degrading and sulfur-related bacteria, accompany chronic warming. A higher ratio of sulfate-reducing bacteria compared to sulfide oxidizers was found in the warming treatment which may result in the collapse of the seagrasses, due to toxic levels of sulfide. Differentiating predicted pathways for warmest temperatures were related to sulfur and nitrogen cycles, suggest an increase of the microbial metabolism, and possible seagrass protection strategies through the production of isoprene. These structural and compositional variations in the associated microbiome offer early insights into the ecological status of seagrasses. Certain taxa/genes/pathways may serve as markers for specific stresses. Monitoring programs should integrate this aspect to identify early indicators of seagrass health. Understanding microbiome changes under stress is crucial for the use of potential probiotic taxa to mitigate climate change effects. Broader-scale examination of seagrass-microorganism interactions is needed to leverage knowledge on host-microbe interactions in seagrasses.FRH/BPD/116774/2016; CEECINST/00114/2018info:eu-repo/semantics/publishedVersio
Unravelling the chemical nature of the spawning-inducing pheromone (SIP) in the pacific oyster (Magallana gigas)
No full textIn external fertilisation, spawning synchrony is often mediated by pheromones. However, their chemical nature is rarely well-established; this is particularly true for bivalves. This study used an electrophysiological technique—the electro-osphradiogram (EOsG)—to investigate the spawning-inducing pheromone (SIP) in the Pacific oyster (Magallana gigas), a species of economic and environmental relevance. Recording the electrophysiological response of the osphradium to conspecific sperm milt and its fractions, we show that the SIP is multicomponent, likely proteinaceous—with at least one component linked to the spermatozoa and the other components in free solution—and all resistant to freezing. At least three active components are involved: one of about 35 kDa, one between 3 and 10 kDa and one of less than 3 kDa. All three, alone, evoke responses from the osphradium, but all three must probably be present to evoke the full biological response—gamete release— in the receiver. All three are likely polar; none were retained by a range of solid-phase extraction cartridges. We suggest that the EOsG will be useful to isolate and identify the individual components of the oyster SIP. Successful identification of the SIP will represent an important step towards more sustainable and efficient bivalve hatchery practices.UID/04326/2025; UID/PRR/04326/202
Waves of innovation: the role of sustainability in driving impact in the blue economy – a PLS-SEM approach
No full textThe Blue Economy, with its emphasis on ocean-based industries, is critical for achieving sustainable development. This study investigates the intricate relationship between sustainability, innovation, and their economic, environmental, and social impacts within Portugal’s Blue Economy. Partial Least Squares Structural Equation Modeling (PLS-SEM) was used to test the hypothesized relationships between sustainability, innovation, and triple bottom line (TBL) outcomes based on survey data from firms operating in the sector. The findings confirm that innovation acts as both a direct outcome of sustainability efforts and a mechanism for mediating its impacts on economic and environmental performance. However, no significant direct or mediating effects were observed for social outcomes, highlighting a persistent gap in this dimension that requires further research. The study contributes to both theory and practice by highlighting the strategic integration of sustainability into organizational innovation processes and its role in enhancing multidimensional performance. By identifying critical pathways and barriers, this study offers valuable guidance for policymakers and industry leaders striving to enhance the long-term sustainability of the Blue Economy.CEEC—INST/00052/2021/CP2792/CT000
Building resilience in tourism firms: evidence from COVID-19
No full textMultiple factors determine tourism companies' capacity to resist and overcome disruptive events, such as pandemics or wars. This paper investigates this issue using a sensitivity index and finds that reductions in human capital, bigger size, and higher past profitability diminish resilience, while higher leverage and capital intensity strengthen it. Our findings further suggest that these effects differ across countries and underscore the negative consequences of Eurozone membership. This paper broadens our understanding of how companies can improve their resilience, providing valuable insights for future preparedness strategies for tourism firms and policymakers.UIBD/152309/2021, UID/0402
Stone tool shaping without direct cultural transmission
No full textWhile environment and biology play important roles, the complexity and variability of human life today depends in many ways on special cultural processes. Terminologies differ, but the key insight is that these processes are required to enable and to produce copies of behavior or artifacts that otherwise lie fully or partly beyond individual reach. Such “know-how copying” has proven rare in the animal kingdom, and is nearly or fully absent in contemporary apes, suggesting an evolution in hominins. It has been claimed that the earliest widely accepted instances of shaped stone artifacts – handaxes, which appear with the Acheulean (c. 1.9–1.6 Mya) – must have required know-how copying. The argument holds that the knowledge of how to shape (shaping know-how) handaxes is beyond individual reach in principle. If true, handaxes would be a valid marker for the presence of know-how copying. We tested this specific claim in two complementary studies using the “puppet method,” a new methodology that experimentally disentangles knapping know-how and shaping know-how. Knapping-naïve “puppeteers” were tasked with replicating target shapes by directing the flake removals of an expert “puppet” knapper, who was not shown the target shapes. As a validation of the puppet method, we first tested if knappingnaïve puppeteers could shape glass blanks into novel, non-archaeological shapes (Arbitrary Shape Study). Two types of analyses, a sorting task and geometric morphometric analyses, confirmed that they could. We then tested whether knapping-naïve puppeteers could replicate an Acheulean handaxe target shape in stone by directing the puppet knapper (Handaxe Study). Three expert lithic archaeologists independently classified the outcomes and confirmed that naïve participants successfully created handaxe shapes. Across both studies, our findings indicate that not all shaping know-how requires direct access to cultural models, and this also holds true for handaxe shaping per se. This conclusion aligns with recent calls for a reorientation in the search for the origins of knowhow copying in the hominin lineage.2022.13283.B; UID/04211/202