The lithic assemblage of Barranco León (BL), attributed to the Oldowan techno-complex, contributes valuable information to reconstruct behavioral patterning of the first hominins to disperse into ...Western Europe. This archaic stone tool assemblage comprises two, very different groups of tools, made from distinct raw materials. On the one hand, a small-sized toolkit knapped from Jurassic flint, comprising intensively exploited cores and small-sized flakes and fragments and, on the other hand, a large-sized limestone toolkit that is mainly linked to percussive activities. In recent years, the limestone macro-tools have been the center of particular attention, leading to a re-evaluation of their role in the assemblage. Main results bring to light strict hominin selective processes, mainly concerning the quality of the limestone and the morphology of the cobbles, in relation to their use-patterning. In addition to the variety of traces of percussion identified on the limestone tools, recurrences have recently been documented in their positioning and in the morphology of the active surfaces. Coupled with experimental work, this data has contributed to formulating hypothesis about the range of uses for these tools, beyond stone knapping and butchery, for activities such as: wood-working or tendon and meat tenderizing. The abundance of hammerstones, as well as the presence of heavy-duty scrapers, are special features recognized for the limestone component of the Barranco León assemblage. This paper presents, for the first time, another characteristic of the assemblage: the presence of polyhedral and, especially, subspheroid morphologies, virtually unknown in the European context for this timeframe. We present an analysis of these tools, combining qualitative evaluation of the raw materials, diacritical study, 3D geometric morphometric analysis of facet angles and an evaluation of the type and position of percussive traces; opening up the discussion of the late Oldowan beyond the African context.
The Guadix-Baza Basin (GBB) in Andalucía, Spain, comprises palaeontological and archaeological sites dating from the Early Pliocene to the Middle Pleistocene, including some of the earliest sites ...with evidence for the presence of early humans (Homo sp.) in Europe. Thus, the history of climate and environments in this basin contributes significantly to our understanding of the conditions under which early humans spread into Europe during the Early Pleistocene. Here we present estimates of precipitation and primary productivity in the GBB from the Pliocene to the Middle Pleistocene based on dental ecometrics in fossil communities of large herbivorous mammals, and perform an ecometrics-based distribution modelling to analyse the environmental conditions of Early and Middle Pleistocene human sites in Europe. Our results show that Early Pleistocene humans generally occupied on average relatively diverse habitats with ecotones, such as woodlands and savannas, but avoided very open and harsh (cool or dry) environments. During the Middle Pleistocene in Europe, humans occupied a comparatively much broader range of environments than during the Early Pleistocene, but were on average more concentrated in environments where the dental ecometric of mammals indicate wooded palaeoenvironments. In the earliest human occupation sites of the GBB, Barranco León and Fuente Nueva 3, the mean annual precipitation and net primary production estimates indicate climatic conditions close to modern Mediterranean sclerophyllous woodland environments, but with slightly higher primary productivity, indicating some similarity with East African woodlands. On the other hand, the environments did not resemble African grassland savannas. The browse-dominated diets of ungulates from Barranco León and Fuente Nueva 3 further suggest palaeoenvironments where grasses were a minor component of the vegetation. In the slightly older site of Venta Micena that has no evidence for the presence of hominins, dental ecometric estimates indicate climate and environments similar to Mediterranean “forest steppe” environments existing in the surroundings of Baza today. Grasses were prevalent in the diet of some taxa, especially equids, in Venta Micena, but most of the species show browse-dominated diets even there.
•Plio-Pleistocene climate history of the Guadix-Baza Basin was reconstructed based on large mammal dental ecometrics.•The climate during the Pleistocene ranged from that of the modern Mediterranean to slightly more humid and productive.•Environments in the Guadix-Baza Basin during the Pleistocene were mostly Mediterranean woodlands and shrublands.•There were hardly any grazers among the ungulates of the three Orce sites studied, suggesting grass-poor paleoenvironments.•Early humans dispersed in Europe during the Early Pleistocene in climatically mild environments, avoiding harsh conditions.
Venta Micena is an area containing several palaeontological sites marking the beginning of the Calabrian stage (Early Pleistocene). The richness of the fossil accumulation including species of Asian, ...African and European origin, makes Venta Micena a key site for the the palaeoecological and palaeoenvironmental study of southern Europe during the Early Pleistocene. Thus, research has been focused on Venta Micena 3, which was originally interpreted as a single palaeosurface associated with a marshy context, in which most of the fauna was accumulated by Pachycrocuta brevirostris. Recent excavations have unearthed a new site, Venta Micena 4, located in the same stratigraphic unit (Unit C) and in close proximity to Venta Micena 3. Here we show the first analyses regarding the taphonomic and spatial nature of this new site, defining two stratigraphic boundaries corresponding to two different depositional events. Furthermore, the taphonomic analyses of fossil remains seem to indicate a different accumulative agent than Pachycrocuta, thus adding more complexity to the palaeobiological interpretation of the Venta Micena area. These results contribute to the discussion of traditional interpretations made from Venta Micena 3.
Artificial neural network-based electro-optic chipsets constitute a very promising platform because of its remarkable energy efficiency, dense wavelength parallelization possibilities and ultrafast ...modulation speeds, which can accelerate computation by many orders of magnitude. Furthermore, since the optical field carries information in both amplitude and phase, photonic hardware can be leveraged to naturally implement complex-valued neural networks (CVNNs). Operating with complex numbers may double the internal degrees of freedom as compared with real-valued neural networks, resulting in twice the size of the hardware network and, thus, increased performance in the convergence and stability properties. To this end, the present work revolves on the concept of CVNNs by offering a design, and simulation demonstration, for an electro-optical dual phase and amplitude modulator implemented by integrating a transparent conducting oxide (TCO) in a silicon waveguide structure. The design is powered by the enhancement of the optical-field confinement effect occurring at the epsilon-near-zero (ENZ) condition, which can be tuned electro-optically in TCOs. Operating near the ENZ resonance enables large changes on the real and imaginary parts of the TCO’s permittivity. In this way, phase and amplitude (dual) modulation can be achieved in single device. Optimal design rules are discussed in-depth by exploring device’s geometry and voltage-dependent effects of carrier accumulation inside the TCO film. The device is proposed as a complex-valued activation function for photonic neural systems and its performance tested by simulating the training of a photonic hardware neural network loaded with our custom activation function.
We present a methodology to simulate the quantum thermodynamics of thermal machines which are built from an interacting working medium in contact with fermionic reservoirs at a fixed temperature and ...chemical potential. Our method works at a finite temperature, beyond linear response and weak system-reservoir coupling, and allows for nonquadratic interactions in the working medium. The method uses mesoscopic reservoirs, continuously damped toward thermal equilibrium, in order to represent continuum baths and a novel tensor-network algorithm to simulate the steady-state thermodynamics. Using the example of a quantum-dot heat engine, we demonstrate that our technique replicates the well-known Landauer-Büttiker theory for efficiency and power. We then go beyond the quadratic limit to demonstrate the capability of our method by simulating a three-site machine with nonquadratic interactions. Remarkably, we find that such interactions lead to power enhancement, without being detrimental to the efficiency. Furthermore, we demonstrate the capability of our method to tackle complex many-body systems by extracting the superdiffusive exponent for high-temperature transport in the isotropic Heisenberg model. Finally, we discuss transport in the gapless phase of the anisotropic Heisenberg model at a finite temperature and its connection to charge conjugation parity, going beyond the predictions of single-site boundary driving configurations.
A protocol to successfully transmit the huanglongbing (HLB) pathogen, '
Liberibacter asiaticus', between citrus plants by using the Asian citrus psyllid (ACP) and an alternative way to help growers ...control ACP are proposed. Best results were obtained when pathogen acquisition by adults reared on fully symptomatic '
Liberibacter asiaticus'-positive plants, latency, and inoculation occurred at ambient air temperatures ranging from 24 to 28°C and when a single infective adult ACP was confined for 7 days on soft, newly developing vegetative shoots (stages v2 to v4). No infection resulted from confinement of infective ACP adults on mature leaves (stage v6). Under the described conditions, single ACP adults could successfully transmit '
Liberibacter asiaticus' to an average of 56.5% (35 to 83%) of plantlets with v2 to v4 shoots growing in 0.3-liter tubes and to 80.5% (76 to 86%) of plants with v2 to v4 shoots growing in 4.7-liter pots. The use of single insects and plantlets reduces labor, space, and other resources necessary to undertake transmission tests. It also reduces time needed for transmission studies and should help accelerate research on HLB. The results were used to develop an index for favorability to infection (IFI) to determine orchard vulnerabilities to '
Liberibacter asiaticus'. The IFI is based on the heterogeneous population of new shoots that occurs on tree canopies and may offer alternative or complementary alternatives to the laborious and costly insect surveys currently used in most instances to determine threshold levels for insecticide applications.
The prevalence of nonalcoholic fatty liver disease (NAFLD) is high. NAFLD is linked to obesity, diabetes mellitus, and hypertriglyceridemia. Approximately 20% of patients with NAFLD will eventually ...develop cirrhosis. Our purpose was to investigate whether resveratrol decreased hepatic steatosis in an animal model of steatosis, and whether this therapeutic approach resulted in a decrease in tumor necrosis factor alpha (TNF-alpha) production, lipid peroxidation and oxidative stress.
Male Wistar CRL: Wi (Han) (225 g) rats were randomized into three groups. A control group (n = 12) was given free access to regular dry rat chow for 4 weeks. The steatosis (n = 12) and resveratrol (n = 12) groups were given free access to feed (a high carbohydrate-fat free modified diet) and water 4 days per week, and fasted for the remaining 3 days for 4 weeks. Rats in the resveratrol group were given resveratrol 10 mg daily by the oral route. All rats were killed at 4 weeks and assessed for fatty infiltration and bacterial translocation. Levels of TNF-alpha in serum, hepatic malondialdehyde (MDA), oxidative stress (superoxide dismutase, glutathione peroxidase, catalase and nitric oxide synthase) and biochemical parameters were measured.
Fat deposition was decreased in the resveratrol group as compared to the steatosis group (Grade 1 vs Grade 3, P < 0.05). TNF-alpha and MDA levels were significantly increased in the steatosis group (TNF-alpha; 33.4 +/- 5.2 vs 26.24 +/- 3.47 pg/ml and MDA; 9.08 +/- 0.8 vs 3.17 +/- 1.45 muM respectively, P < 0.05). This was accompanied by increased superoxide dismutase, glutathione peroxidase and catalase and decreased nitric oxide synthase in the liver of resveratrol group significantly (P < 0.05 vs steatosis group). Bacterial translocation was not found in any of the groups. Glucose levels were decreased in the group of rats given resveratrol (P < 0.05).
Resveratrol decreased NAFLD severity in rats. This effect was mediated, at least in part, by TNF-alpha inhibition and antioxidant activities.
The oldest handaxes in Europe: fact or artefact? Jiménez-Arenas, Juan Manuel; Santonja, Manuel; Botella, Miguel ...
Journal of archaeological science,
12/2011, Letnik:
38, Številka:
12
Journal Article
Recenzirano
Hominin presence is well documented in a number of Early Pleistocene and early Middle Pleistocene European localities. However, the evidence currently available indicates that Acheulean handaxes ...spread in the fluvial basins of Western Europe during MIS 11, ∼400 kyr ago, associated with
Homo heidelbergensis, although a number of early Middle Pleistocene Acheulean assemblages have been dated from MIS 16 onwards. For this reason, the magnetostratigraphic dating in Southeast Spain of two archaeological localities, the open-air site of Solana del Zamborino (SZ) and the rock-shelter site of Cueva Negra del Estrecho del Quípar (EQ), that put back the appearance of handaxes to the Early-Middle Pleistocene limit (
Scott and Gibert, 2009) is of particular interest, as the new ages suggest that
H. heidelbergensis was a contemporary of
H. antecessor that had the ability to produce Levallois debitage and to control fire during the Early-Middle Pleistocene transition. However, we have detected a number of errors in the interpretation of the archaeological assemblage from the first site as well as striking discrepancies with the original faunal lists published for both localities, with several large mammal species that are omitted or arbitrarily changed to make the assemblages consistent with the new ages deduced from magnetostratigraphy. For this reason, we suggest that: (1) the finding of reverse polarity in the sediments sampled for paleomagnetism in SZ may simply record one of the polarity reversals that took place during the Brunhes Chron, although the use by
Scott and Gibert (2009) of a composite stratigraphic column precludes correlating these levels with a specific reversal; and (2) the fauna and tools of EQ correspond to the late Middle Pleistocene sedimentary infillings of this karst site, while the samples taken for paleomagnetism belong to a previous sedimentary cycle during the Matuyama Chron. Such interpretations would be in better agreement with the age estimates provided by biostratigraphy and also with the currently accepted chronology for the appearance of Acheulean industries in Western Europe.
► The chronology of the earliest Acheulean in Southeast Spain is discussed. ► The magnetostratigraphic evidence for two archaeological localities is re-evaluated. ► The taxonomic affinities of the mammal species identified are discussed. ► We suggest a late Middle Pleistocene age for both localities.
PDF
