Browsing by Issue Date, starting with "2020-03"
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- Faunal turnover at Mille-Logya (Plio-Pleistocene, Ethiopia) reflects in situ environmental change: implications for the origins of HomoPublication . Barr, W. Andrew; Geraads, Denis; Reed, Denne; Bobe, Rene; Wynn, Jonathan; Alemseged, ZeresenayThe lower Awash Valley of Ethiopia preserves a significant record of Australopithecus afarensis at Hadar and Dikika in addition to the earliest fossil yet attributed to Homo from Ledi-Geraru at 2.8 Ma. However, understanding the context of the extinction of A. afarensis and the origin of Homo is hampered by the limited preservation of sediments between 2.9 – 2.3 Ma in the region. The Mille-Logya Project (MLP) preserves fossiliferous sediments post-dating 2.9 Ma. Here we present a quantitative analysis of the MLP mammalian fauna and explore implications of MLP faunal change for the origin of Homo.
- Using remote sensing and machine learning to reconstruct paleoenvironmental features in the Koobi Fora FormationPublication . Dorans, Elizabeth R.; Coelho, Joao D'Oliveira; Anemone, Robert L.; Bobe, Rene; Carvalho, Susana; Forrest, Frances; Braun, David R.Advances in Geographic Information Systems and Remote Sensing technologies have the potential to revolutionize archaeological and paleontological fieldwork. Machine learning models have been effective in identifying conditions ideal for preservation, exposure, and discovery of fossils in a range of geographic contexts. Researchers working in the Koobi Fora Formation of northern Kenya have long inquired about the geographic patterning of extinct fauna and their respective paleoenvironments. This project is the first attempt to use machine learning techniques to capture paleoecological patterns utilizing topographical and spectral variables that may be predictive of the input of aquatic components in the paleoenvironments of the Koobi Fora Formation.
- Breve caraterização do porta-enxerto ‘Gou Tou’ e a sua adequação à citricultura portuguesaPublication . Reis, Adélia; Duarte, A.Os porta-enxertos predominantes hoje na bacia do Mediterrâneo são as citranjeiras, sobretudo a ‘Carrizo’. A laranjeira ‘Gou Tou’ é considerada um híbrido natural de laranjeira azeda, e é um dos porta-enxertos mais comuns na China. Este híbrido pode contribuir para a diversificação dos porta-enxertos usados em Portugal e em países vizinhos. Parece ser tolerante à Tristeza, cresce bem em solos calcários, é tolerante à salinidade e à seca. O seu efeito sobre a produtividade e a qualidade do fruto devem ser estudados.
- Biodiversity of intertidal food webs in response to warming across latitudesPublication . Gauzens, Benoit; Rall, Bjoern C.; Mendonca, Vanessa; Vinagre, Catarina; Brose, UlrichGlobal warming will affect food-web structure and species persistence, and real world data is needed for better prediction. Combining species counts and temperature data from rock pools with dynamic modelling predicts biodiversity increases in arctic to temperate regions and declines in the tropics. Global warming threatens community stability and biodiversity around the globe. Knowledge of the mechanisms underlying the responses to rising temperatures depends heavily on generic food-web models that do not account for changes in network structure along latitudes and temperature gradients. Using 124 marine rock-pool food webs sampled across four continents, we show that despite substantial variation in ambient temperature (mean 11.5-28.4 degrees C), similar empirical food-web and body-mass structures emerge. We have used dynamic modelling to test whether communities from warmer regions are more sensitive to warming and found a general hump-shaped relationship between simulated biodiversity and temperature (gradient from 0-50 degrees C). This implies that an expected anthropogenic global warming of 4 degrees C should increase biodiversity in arctic to temperate regions while biodiversity in tropical regions should decrease. Interestingly, simulations of synthetic networks did not yield similar results, which stresses the importance of considering the specificities of natural food webs for predicting community responses to environmental changes.
- Sinonasal undifferentiated carcinoma (SNUC): from an entity to morphologic pattern and back again-a historical perspectivePublication . Agaimy, Abbas; Franchi, Alessandro; Lund, Valerie J.; Skalova, Alena; Bishop, Justin A.; Triantafyllou, Asterios; Andreasen, Simon; Gnepp, Douglas R.; Hellquist, Henrik; Thompson, Lester D. R.; Rinaldo, Alessandra; Ferlito, AlfioSince the first description of sinonasal undifferentiated carcinoma (SNUC) as a distinctive highly aggressive sinonasal neoplasm with probable origin from the sinonasal mucosa (Schneiderian epithelium), SNUC has been the subject of ongoing study and controversy. In particular, the SNUC category gradually became a "wastebasket" for any undifferentiated or unclassifiable sinonasal malignancy of definite or probable epithelial origin. However, with the availability of more specific and sensitive immunohistochemical antibodies and increasing implementation of novel genetic tools, the historical SNUC category became the subject of progressive subdivision leading to recognition of specific genetically defined, reproducible subtypes. These recently recognized entities are characterized by distinctive genetic aberrations including NUTM1-rearranged carcinoma (NUT carcinoma) and carcinomas associated with inactivation of different members of the SWI/SNF chromatin-remodeling gene complex such as SMARCB1-deficient and less frequently SMARCA4-deficient carcinoma. The ring became almost closed, with recent studies highlighting frequent oncogenic IDH2 mutations in the vast majority of histologically defined SNUCs, with a frequency of 82%. A review of these cases suggests the possibility that "true SNUC" probably represents a distinctive neoplastic disease entity, morphologically, phenotypically, and genetically. This review addresses this topic from a historical perspective, with a focus on recently recognized genetically defined subsets within the SNUC spectrum.
- Surface and deep water variability in the Western Mediterranean (ODP Site 975) during insolation cycle 74: high-resolution calcareous plankton and molecular biomarker signalsPublication . Quivelli, Ornella; Marino, Maria; Rodrigues, Teresa; Girone, Angela; Maiorano, Patrizia; Abrantes, Fatima; Salgueiro, Emilia; Bassinot, FrankWe reconstructed changes in productivity and surface/subsurface and deep-water dynamics in the Western Mediterranean through a multi-proxy study of Ocean Drilling Program Site 975 between late Marine Isotope Stage (MIS) 20 and early interglacial MIS 19. Our high-resolution study (down to similar to 200-year resolution) combines calcareous plankton assemblages (coccolithophores and foraminifera), biomarkers (C-37-alkenones, n-alkanes, n-alcohols) and elemental proxies (total organic carbon, total nitrogen, calcium carbonate). Surface water conditions are derived (i) from high-resolution delta O-18 and delta C-13 records obtained from the planktonic foraminifer Globigerina bulloides, and (ii) from summer and winter, foraminifera-based sea surface temperature reconstructions (SSTJAS-foram, SSTJFM-foram) achieved through transfer function. The integration of the whole dataset makes it possible to identify in the Balearic Sea, and to accurately characterize for the first time, an Organic Rich Layer (ORL) during latest MIS 20-early MIS 19, close to i-cycle 74. Its presence is marked firstly by higher values of total nitrogen (TN) and an increase of total C-37-alkenone and total organic carbon (TOC) preserved in the sediments. The multi-proxy approach reveals that the deglacial phase played a prominent role for ORL formation that was characterized by centennial scale phases. The alcohol preservation index (API) suggests that the shoaling of the circulation, which boosted marine productivity, started in the deglaciation and, in combination with freshening by Atlantic water inflow/riverine input and surface water buoyancy during sea level rising, culminated during the ORL event. At this time calcareous plankton proliferated on subsurface-surface waters, benefiting from ameliorating conditions, which promoted maximum marine productivity and higher organic matter preservation on the seafloor.
- Resistive switching of silicon-silver thin film devices in flexible substratesPublication . Dias, C.; Leitao, D. C.; Freire, C. S. R.; H, Gomes; Cardoso, S.; Ventura, J.Novel applications for memory devices demand nanoscale flexible structures. In particular, resistive switching (RS) devices are promising candidates for wearable and implantable technologies. Here, the Pt/Si/Ag/TiW metal-insulator-metal structure was fabricated and characterized on top of flexible substrates using a straightforward microfabrication process. We also showed that these substrates are compatible with sputtering deposition. RS was successfully achieved using both commercial cellulose cleanroom paper and bacterial cellulose, and polymer (PET) substrates. The bipolar switching behavior was observed for both flat and bent (under a radius of 3.5 mm) configurations. The observed phenomenon was explained by the formation/rupture of metallic Ag filaments in the otherwise insulating Si host layer.
- Care and the shadow of the fourth age: how does home care get caught up in it and how does it stay away from it?Publication . São José, JoséThis article examines how care encounters at the elders' homes are forged, and how the way these encounters are forged avoids or evokes the social imaginary of the fourth age. Data were gathered in Portugal from elders receiving home care (16 cases), their care workers (eight cases) and family carers (six cases), through participant observation and informal conversations (conducted at the elders' homes), as well as focus groups. The collected data were analysed according to the procedures of Framework Analysis. This study found five forms of care encounters - marked by conflict, infantilisation, burden, harmony and indifference - the harmony form being the only one found to maintain the fourth age at a distance. It concludes that home care has a Janus-like nature in relation to the fourth age, and that the way home care encounters are forged depends on the conditions of the care settings and the actions of all participants in care encounters. It also concludes that it is difficult to maintain the social imaginary of the fourth age at a distance when the elders exhibit high levels of infirmity. Finally, it concludes that family carers play a crucial role in the way care encounters unfold. Implications for practice and policy include vocational training regarding the relational component of care, and information and educational programmes for family carers.
- Non-indigenous species in soft-sediments: are some estuaries more invaded than others?Publication . Cabral, Sara; Carvalho, Frederico; Gaspar, Miguel; Ramajal, Joao; Sa, Erica; Santos, Catia; Silva, Gilda; Sousa, Antonio; Costa, Jose Lino; Chainho, PaulaNon-indigenous species (NIS) are increasingly widespread and abundant in coastal areas, hence being considered indicators to assess the environmental status of marine waters under the Marine Strategy Framework Directive. However, information on the effects of biological invasions on species composition and abundance is still scarce, particularly for soft-sediment benthic communities, which remain poorly understood. Therefore, the present study aimed at monitoring the benthic communities of two Portuguese estuarine systems, with a particular focus on NIS. Sampling surveys were conducted at the Tagus and Sado estuaries, in three different years. Invertebrate communities were collected at sampling stations located along the estuarine gradient, using a clam dredge, and several water and sediment parameters were measured at the same locations. NIS represented nearly one fourth (23%) of the total observed individuals across all years and estuaries, with Ruditapes philippinarum accounting for 22% of the total abundance across estuaries and years. Although both estuaries presented a similar total number of species (91 at the Tagus and 81 at the Sado), three-fold more NIS were identified at the Tagus estuary. The frequency of occurrence of the NIS Crassostrea (Magallana) gigas, Mya arenaria and Panopeus occidentalis increased significantly over the three years at the Tagus estuary and decreased significantly for Dyspanopeus sayi from 2015 to 2018. The Tagus and Sado estuaries presented distinct and diverse communities, with the abundance of R. philippinarum being eleven-fold greater at the Tagus estuary than at the Sado estuary. This study provides a baseline list of the NIS occurring in two of the main Portuguese estuarine systems, as well as an approach to estimate NIS abundance, richness, frequency of occurrence and community diversity. Although most studies on NIS impacts have focused on single species, the assessment of the environmental status of marine waters requires that overall impacts of NIS on marine ecosystems are determined. This study indicated metrics that are appropriate to evaluate changes in soft-sediment benthic communities associated to the introduction of NIS.
- On difunctionality of class relationsPublication . Hoefnagel, Michael; Janelidze, Zurab; Rodelo, DianaFor a given variety V of algebras, we define a class relation to be a binary relation R subset of S(2)which is of the form R = S-2 boolean AND K for some congruence class K on A(2), where A is an algebra in V such that S subset of A. In this paper we study the following property of V : every reflexive class relation is an equivalence relation. In particular, we obtain equivalent characterizations of this property analogous to well-known equivalent characterizations of congruence-permutable varieties. This property determines a Mal'tsev condition on the variety and in a suitable sense, it is a join of Chajda's egg-box property as well as Duda's direct decomposability of congruence classes.