79 research outputs found
Evidence for bone grease rendering during the Upper Paleolithic at Vale Boi (Algarve, Portugal)
El análisis traceológico como medio de aproximación a las actividades realizadas en los asentamientos: el ejemplo de los yacimientos del Paleolítico Superior de Vale Boi y Lapa do Picareiro (Portugal)
Lapa do Picareiro, un asentamiento de caza magdaleniense en la Estremadura portuguesa
Lapa do Picareiro es un yacimiento situado en la Estremadura portuguesa, en la Serra d’Aire. Los estudios zooarqueológicos llevados a cabo nos hablan de un lugar especializado de caza y procesado de distintas especies animales durante el magdaleniense y el epipaleolítico. Por su parte, los análisis líticos confirman la presencia de un utillaje en el que destacan las laminillas de dorso empleadas como proyectiles y las lascas y láminas destinadas al corte de carne y al tratamiento de la piel.Lapa do Picareiro is a cave site located in Serra d’Aire, Portuguese Estremadura. Zooarchaeological studies suggest that the cave was a specialized site for hunting and processing animals during the Magdalenian and the Epipaleolithic. Lithic analyses seem to confirm this idea with the presence of backed bladelets used as projectile points and flakes with evidence of cutting meat and hide processing
Discrimination of idiopathic Parkinson's disease and vascular parkinsonism based on gait time series and the levodopa effect
Idiopathic Parkinson's disease (IPD) and vascular parkinsonism (VaP) present highly overlapping phenotypes, making it challenging to distinguish between these two parkinsonian syndromes. Recent evidence suggests that gait assessment and response to levodopa medication may assist in the objective evaluation of clinical differences. In this paper, we propose a new approach for gait pattern differentiation that uses convolutional neural networks (CNNs) based on gait time series with and without the influence of levodopa medication. Wearable sensors positioned on both feet were used to acquire gait data from 14 VaP patients, 15 IPD patients, and 34 healthy subjects. An individual's gait features are affected by physical characteristics, including age, height, weight, sex, and walking speed or stride length. Therefore, to reduce bias due to intersubject variations, a multiple regression normalization approach was used to obtain gait data. Recursive feature elimination using the linear support vector machine, lasso, and random forest were applied to infer the optimal feature subset that led to the best results. CNNs were implemented by means of various hyperparameters and feature subsets. The best CNN classifiers achieved accuracies of 79.33%±6.46, 82.33%±10.62, and 86.00%±7.12 without (off state), with (on state), and with the simultaneous consideration of the effect of levodopa medication (off/on state), respectively. The response to levodopa medication improved classification performance. Based on gait time series and response to medication, the proposed approach differentiates between IPD and VaP gait patterns and reveals a high accuracy rate, which might prove useful when distinguishing other diseases related to movement disorders.This research was partially financed by NORTE2020 and FEDER within the project NORTE-01–0145-FEDER- 000026 (DeM-Deus Ex Machina) and by Portuguese Funds through FCT (Fundação para a Ciência e a Tecnologia) within the Projects UIDB/00013/2020, UIDP/00013/2020 and UIDB/00319/2020
Compensatory postural adjustments in na oculus virtual reality environment and the risk of falling in Alzheimer’s disease
Background/Aims
Alzheimer's disease (AD) patients have an impaired ability to quickly reweight central sensory dependence in response to unexpected body perturbations. Herein, we aim to study provoked compensatory postural adjustments (CPAs) in a conflicting sensory paradigm with unpredictable visual displacements using virtual reality goggles.
Methods
We used kinematic time-frequency analyses of two frequency bands: a low-frequency band (LB; 0.3-1.5 Hz; mechanical strategy) and a high-frequency band (HB; 1.5-3.5 Hz; cognitive strategy). We enrolled 19 healthy subjects (controls) and 21 AD patients, divided according to their previous history of falls.
Results
The AD faller group presented higher-power LB CPAs, reflecting their worse inherent postural stability. The AD patients had a time lag in their HB CPA reaction.
Conclusion
The slower reaction by CPA in AD may be a reflection of different cognitive resources including body schema self-perception, visual motion, depth perception, or a different state of fear and/or anxiety.The Centro ALGORITMI was funded by the FP7 Marie Curie ITN Neural Engineering Transformative Technologies (NETT) project. The authors have no conflicts of interest to report.info:eu-repo/semantics/publishedVersio
Gait classification of patients with Fabry's disease based on normalized gait features obtained using multiple regression models
Diagnosis of Fabry disease (FD) remains a challenge mostly due to its rare occurrence and phenotipical variability, with considerable delay between onset and clinical diagnosis. It is then of extreme importance to explore biomarkers capable of assisting the earlier diagnosis of FD. There is growing evidence supporting the use of gait assessment in the diagnosis and management of several neurological diseases. In fact, gait abnormalities have previously been observed in FD, justifying further investigation. The aim of this study is to evaluate the effectiveness of different machine learning strategies when distinguishing patients with FD from healthy controls based on normalized gait features. Gait features of an individual are affected by physical characteristics including age, height, weight, and gender, as well as walking speed or stride length. Therefore, in order to reduce bias due to inter-subject variations a multiple regression (MR) normalization approach for gait data was performed. Four different machine learning strategies - Support Vector Machines (SVM), Random Forest (RF), Multiple Layer Perceptrons (MLPs), and Deep Belief Networks (DBNs) - were employed on raw and normalized gait data. Wearable sensors positioned on both feet were used to acquire the gait data from 36 patients with FD and 34 healthy subjects. Gait normalization using MR revealed significant differences in percentage of stance phase spent in foot flat and pushing (p < 0.05), with FD presenting lower percentages in foot flat and higher in pushing. No significant differences were observed before gait normalization. Support Vector Machine was the superior classifier achieving an FD classification accuracy of 78.21% after gait normalization, compared to 71.96% using raw gait data. Gait normalization improved the performance of all classifiers. To the best of our knowledge, this is the first study on gait classification that includes patients with FD, and our results support the use of gait assessment on the clinical assessment of FD.This work was partially supported by the projects NORTE-01-0145-
FEDER- 000026 (DeM-Deus Ex Machina) financed by NORTE2020 and
FEDER, and the Pluriannual Funding Programs of the research centres CMAT
and Algoritm
Variabilité des techniques de récolte et traitements des céréales dans l'occident Méditerranéen au Néolithique Ancien et Moyen: facteurs environnementaux, économiques et sociaux
La reconstitution des techniques agricoles préhistoriques constitue un élément fondamental pour la compréhension du processus d’expansion de l’agriculture en Méditerranée occidentale. Dans le cadre d’un projet européen rassemblant des tracéologues et des carpologues espagnols et français, nous avons, dans une première phase, étudié les méthodes de récolte des céréales pratiquées durant le Néolithique en Espagne et dans le Sud de la France, du Néolithique ancien au Néolithique moyen. L’étude des outils de récolte a permis de distinguer trois aires distinctes. Le Sud-Est de l’Espagne est caractérisé par des faucilles courbes avec des éléments insérés obliquement dans le manche. En Catalogne, Languedoc et Provence, la majorité des faucilles sont constituées de longues lames emmanchées parallèlement au manche, mais d’autres modèles existent. En Espagne cantabrique, les céréales étaient récoltées sans faucille. Nos travaux en cours explorent différents facteurs pouvant expliquer cette variabilité : conditions environnementales, types de céréales cultivées, finalités techniques et alimentaires de la culture des céréales, techniques de conservation des céréales, rôle de l’agriculture céréalière dans l’économie, dynamiques historiques de l’expansion et de l’adoption des
innovations néolithiques.Peer Reviewe
On the chronological structure of the solutrean in Southern Iberia
The Solutrean techno-complex has gained particular significance over time for representing a clear demographic and techno-typological deviation from the developments occurred during the course of the Upper Paleolithic in Western Europe. Some of Solutrean's most relevant features are the diversity and techno-typological characteristics of the lithic armatures. These have been recurrently used as pivotal elements in numerous Solutrean-related debates, including the chronological organization of the techno-complex across Iberia and Southwestern France. In Southern Iberia, patterns of presence and/or absence of specific point types in stratified sequences tend to validate the classical ordering of the techno-complex into Lower, Middle and Upper phases, although some evidence, namely radiocarbon determinations, have not always been corroborative. Here we present the first comprehensive analysis of the currently available radiocarbon data for the Solutrean in Southern Iberia. We use a Bayesian statistical approach from 13 stratified sequences to compare the duration, and the start and end moments of each classic Solutrean phase across sites. We conclude that, based on the current data, the traditional organization of the Solutrean cannot be unquestionably confirmed for Southern Iberia, calling into doubt the status of the classically defined type-fossils as precise temporal markers.Fundacao para a Ciencia e Tecnologia [PTDC/HAH/64184/2006, PTDC/HIS-ARQ/117540/2010, SFRH/BD/65527/2009, SFRH/BPD/96277/2013]; National Geographic Society [8045-06]; Wenner-Gren Foundation for Anthropological Research [8290
Earliest Known Use of Marine Resources by Neanderthals
Numerous studies along the northern Mediterranean borderland have documented the use of shellfish by Neanderthals but none of these finds are prior to Marine Isotopic Stage 3 (MIS 3). In this paper we present evidence that gathering and consumption of mollusks can now be traced back to the lowest level of the archaeological sequence at Bajondillo Cave (Málaga, Spain), dated during the MIS 6. The paper describes the taxonomical and taphonomical features of the mollusk assemblages from this level Bj19 and briefly touches upon those retrieved in levels Bj18 (MIS 5) and Bj17 (MIS 4), evidencing a continuity of the shellfishing activity that reaches to MIS 3. This evidence is substantiated on 29 datings through radiocarbon, thermoluminescence and U series methods. Obtained dates and paleoenvironmental records from the cave include isotopic, pollen, lithostratigraphic and sedimentological analyses and they are fully coherent with paleoclimate conditions expected for the different stages. We conclude that described use of shellfish resources by Neanderthals (H. neanderthalensis) in Southern Spain started ∼150 ka and were almost contemporaneous to Pinnacle Point (South Africa), when shellfishing is first documented in archaic modern humans
Fossil Carder Bee's nest from the Hominin locality of Taung, South Africa
The Buxton-Norlim Limeworks southwest of Taung, South Africa, is renowned for the discovery of the first Australopithecus africanus fossil, the ‘Taung Child’. The hominin was recovered from a distinctive pink calcrete that contains an abundance of invertebrate ichnofauna belonging to the Coprinisphaera ichnofacies. Here we describe the first fossil bee’s nest, attributed to the ichnogenus Celliforma, from the Plio-Pleistocene of Africa. Petrographic examination of a cell lining revealed the preservation of an intricate organic matrix lined with the calcitic casts of numerous plant trichomes–a nesting behaviour unique to the modern-day carder bees (Anthidiini). The presence of Celliforma considered alongside several other recorded ichnofossils can be indicative of a dry, savannah environment, in agreement with recent work on the palaeoenvironment of Plio-Pleistocene southern Africa. Moreover, the occurrence of ground-nesting bees provides further evidence that the pink calcrete deposits are of pedogenic origin, rather than speleogenic origin as has previously been assumed. This study demonstrates the potential value of insect trace fossils as palaeoenvironmental indicators
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