1,835 research outputs found
Neanderthal teeth from Lezetxiki (Arrasate, Iberian Peninsula): New insights and reassessment
Objectives: We reassess the taxonomic assignment and stratigraphic context of a permanent upper first molar and a permanent lower third premolar recovered from the archeological site of Lezetxiki in the North of the Iberian Peninsula. Materials and Methods: We assessed the external and internal morphology of the teeth using qualitative descriptions, crown diameters, dental tissue proportions, and geometric morphometrics. The teeth from Lezetxiki were compared with Middle Pleistocene specimens, Neanderthals, Upper Paleolithic modern humans, and recent modern humans. Results: Both teeth were consistent with a Neanderthal classification. The upper first molar shows taurodontism, and its cusp proportions and overall morphology match those of Neanderthals. Geometric morphometric analyses of occlusal anatomy classify this molar as a Neanderthal with a posterior probability of 76%. The lower third premolar, which was originally classified as a lower fourth premolar, also shows a Neanderthal morphology. This premolar is classified as a Neanderthal with a posterior probability of 60%. Discussion: These teeth represent the only adult Neanderthal teeth from the Western Pyrenees region found to date. The teeth were found at a stratigraphic level (designated Level III) that marks the transition level from Mousterian to Aurignacian, and are among the most recent Neanderthal remains from the north of the Iberian Peninsula
Origin and function of short-latency inputs to the neural substrates underlying the acoustic startle reflex
The acoustic startle reflex (ASR) is a survival mechanism of alarm, which rapidly alerts the organism to a sudden loud auditory stimulus. In rats, the primary ASR circuit encompasses three serially connected structures: cochlear root neurons (CRNs), neurons in the caudal pontine reticular nucleus (PnC), and motoneurons in the medulla and spinal cord. It is well-established that both CRNs and PnC neurons receive short-latency auditory inputs to mediate the ASR. Here, we investigated the anatomical origin and functional role of these inputs using a multidisciplinary approach that combines morphological, electrophysiological and behavioral techniques. Anterograde tracer injections into the cochlea suggest that CRNs somata and dendrites receive inputs depending, respectively, on their basal or apical cochlear origin. Confocal colocalization experiments demonstrated that these cochlear inputs are immunopositive for the vesicular glutamate transporter 1 (VGLUT1). Using extracellular recordings in vivofollowed by subsequent tracer injections, we investigated the response of PnC neurons after contra-, ipsi-, and bilateral acoustic stimulation and identified the source of their auditory afferents. Our results showed that the binaural firing rate of PnC neurons was higher than the monaural, exhibiting higher spike discharges with contralateral than ipsilateral acoustic stimulations. Our histological analysis confirmed the CRNs as the principal source of short-latency acoustic inputs, and indicated that other areas of the cochlear nucleus complex are not likely to innervate PnC. Behaviorally, we observed a strong reduction of ASR amplitude in monaural earplugged rats that corresponds with the binaural summation process shown in our electrophysiological findings. Our study contributes to understand better the role of neuronal mechanisms in auditory alerting behaviors and provides strong evidence that the CRNs-PnC pathway mediates fast neurotransmission and binaural summation of the ASR. © 2014 Gómez-Nieto, Horta-Júnior, Castellano, Millian-Morell, Rubio and López
Characteristic Evolution and Matching
I review the development of numerical evolution codes for general relativity
based upon the characteristic initial value problem. Progress in characteristic
evolution is traced from the early stage of 1D feasibility studies to 2D
axisymmetric codes that accurately simulate the oscillations and gravitational
collapse of relativistic stars and to current 3D codes that provide pieces of a
binary black hole spacetime. Cauchy codes have now been successful at
simulating all aspects of the binary black hole problem inside an artificially
constructed outer boundary. A prime application of characteristic evolution is
to extend such simulations to null infinity where the waveform from the binary
inspiral and merger can be unambiguously computed. This has now been
accomplished by Cauchy-characteristic extraction, where data for the
characteristic evolution is supplied by Cauchy data on an extraction worldtube
inside the artificial outer boundary. The ultimate application of
characteristic evolution is to eliminate the role of this outer boundary by
constructing a global solution via Cauchy-characteristic matching. Progress in
this direction is discussed.Comment: New version to appear in Living Reviews 2012. arXiv admin note:
updated version of arXiv:gr-qc/050809
Searches for Lepton Flavour Violation at a Linear Collider
We investigate the prospects for detection of lepton flavour violation in
sparticle production and decays at a Linear Collider (LC), in models guided by
neutrino oscillation data. We consider both slepton pair production and
sleptons arising from the cascade decays of non-leptonic sparticles. We study
the expected signals when lepton-flavour-violating (LFV) interactions are
induced by renormalization effects in the Constrained Minimal Supersymmetric
extension of the Standard Model (CMSSM), focusing on the subset of the
supersymmetric parameter space that also leads to cosmologically interesting
values of the relic neutralino LSP density. Emphasis is given to the
complementarity between the LC, which is sensitive to mixing in both the left
and right slepton sectors, and the LHC, which is sensitive primarily to mixing
in the right sector. We also emphasize the complementarity between searches for
rare LFV processes at the LC and in low-energy experiments.Comment: 19 pages, 10 figure
Theoretical Aspects of Dark Matter Detection
Direct and indirect dark matter detection relies on the scattering of the dark matter candidate on nucleons or nuclei. Here, attention is focused on dark matter candidates (neutralinos) predicted in the minimal supersymmetric standard model and its constrained version with universal input soft supersymmetry-breaking masses. Current expectations for elastic scattering cross sections for neutralinos on protons are discussed with particular attention to satisfying all current accelerator constraints as well as insuring a sufficient cosmological relic density to account for the dark matter in the Universe
The Impact of Global Warming and Anoxia on Marine Benthic Community Dynamics: an Example from the Toarcian (Early Jurassic)
The Pliensbachian-Toarcian (Early Jurassic) fossil record is an archive of natural data of benthic community response to global warming and marine long-term hypoxia and anoxia. In the early Toarcian mean temperatures increased by the same order of magnitude as that predicted for the near future; laminated, organic-rich, black shales were deposited in many shallow water epicontinental basins; and a biotic crisis occurred in the marine realm, with the extinction of approximately 5% of families and 26% of genera. High-resolution quantitative abundance data of benthic invertebrates were collected from the Cleveland Basin (North Yorkshire, UK), and analysed with multivariate statistical methods to detect how the fauna responded to environmental changes during the early Toarcian. Twelve biofacies were identified. Their changes through time closely resemble the pattern of faunal degradation and recovery observed in modern habitats affected by anoxia. All four successional stages of community structure recorded in modern studies are recognised in the fossil data (i.e. Stage III: climax; II: transitional; I: pioneer; 0: highly disturbed). Two main faunal turnover events occurred: (i) at the onset of anoxia, with the extinction of most benthic species and the survival of a few adapted to thrive in low-oxygen conditions (Stages I to 0) and (ii) in the recovery, when newly evolved species colonized the re-oxygenated soft sediments and the path of recovery did not retrace of pattern of ecological degradation (Stages I to II). The ordination of samples coupled with sedimentological and palaeotemperature proxy data indicate that the onset of anoxia and the extinction horizon coincide with both a rise in temperature and sea level. Our study of how faunal associations co-vary with long and short term sea level and temperature changes has implications for predicting the long-term effects of “dead zones” in modern oceans
The physics of spreading processes in multilayer networks
The study of networks plays a crucial role in investigating the structure,
dynamics, and function of a wide variety of complex systems in myriad
disciplines. Despite the success of traditional network analysis, standard
networks provide a limited representation of complex systems, which often
include different types of relationships (i.e., "multiplexity") among their
constituent components and/or multiple interacting subsystems. Such structural
complexity has a significant effect on both dynamics and function. Throwing
away or aggregating available structural information can generate misleading
results and be a major obstacle towards attempts to understand complex systems.
The recent "multilayer" approach for modeling networked systems explicitly
allows the incorporation of multiplexity and other features of realistic
systems. On one hand, it allows one to couple different structural
relationships by encoding them in a convenient mathematical object. On the
other hand, it also allows one to couple different dynamical processes on top
of such interconnected structures. The resulting framework plays a crucial role
in helping achieve a thorough, accurate understanding of complex systems. The
study of multilayer networks has also revealed new physical phenomena that
remain hidden when using ordinary graphs, the traditional network
representation. Here we survey progress towards attaining a deeper
understanding of spreading processes on multilayer networks, and we highlight
some of the physical phenomena related to spreading processes that emerge from
multilayer structure.Comment: 25 pages, 4 figure
Virtual rehabilitation for multiple sclerosis using a Kinect-based system: randomized controlled trial
©Jose-Antonio Lozano-Quilis, Hermenegildo Gil-Gómez, Jose-Antonio Gil-Gómez, Sergio Albiol-Pérez, Guillermo Palacios-Navarro, Habib M Fardoun, Abdulfattah S Mashat. Originally published in JMIR Serious Games (http://games.jmir.org), 12.11.2014.
This is an open-access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work, first published in JMIR Serious Games, is properly cited. The complete bibliographic information, a link to the original publication on http://games.jmir.org, as well as this copyright and license information must be included.Background: The methods used for the motor rehabilitation of patients with neurological disorders include a number of different rehabilitation exercises. For patients who have been diagnosed with multiple sclerosis (MS), the performance of motor rehabilitation exercises is essential. Nevertheless, this rehabilitation may be tedious, negatively influencing patients motivation and adherence to treatment.
Objective: We present RemoviEM, a system based on Kinect that uses virtual reality (VR) and natural user interfaces (NUI) to offer patients with MS an intuitive and motivating way to perform several motor rehabilitation exercises. It offers therapists a new motor rehabilitation tool for the rehabilitation process, providing feedback on the patient s progress. Moreover, it is a low-cost system, a feature that can facilitate its integration in clinical rehabilitation centers.
Methods: A randomized and controlled single blinded study was carried out to assess the influence of a Kinect-based virtual rehabilitation system on the balance rehabilitation of patients with MS. This study describes RemoviEM and evaluates its effectiveness compared to standard rehabilitation. To achieve this objective, a clinical trial was carried out. Eleven patients from a MS association participated in the clinical trial. The mean age was 44.82 (SD 10.44) and the mean time from diagnosis (years) was 9.77 (SD 10.40). Clinical effectiveness was evaluated using clinical balance scales.
Results: Significant group-by-time interaction was detected in the scores of the Berg Balance Scale (P=.011) and the Anterior Reach Test in standing position (P=.011). Post-hoc analysis showed greater improvement in the experimental group for these variables than in the control group for these variables. The Suitability Evaluation Questionnaire (SEQ) showed good results in usability, acceptance, security, and safety for the evaluated system.
Conclusions: The results obtained suggest that RemoviEM represents a motivational and effective alternative to traditional motor rehabilitation for MS patients. These results have encouraged us to improve the system with new exercises, which are currently being developed.This contribution was partially funded by the Generalitat Valenciana ("Ajudes per a la realitzacio de projectes d'I+D per a grups d'investigacion emergents", projecte GV/2012/069) and by the Fundacion Antonio Gargallo ("Ayudas financiadas por la Obra Social de Ibercaja de proyectos de investigacion 2013", proyecto 2013/B001).Lozano Quilis, JA.; Gil Gómez, H.; Gil-Gómez, J.; Albiol Pérez, S.; Palacios Navarro, G.; Fardoun, HM.; Mashat, AS. (2014). Virtual rehabilitation for multiple sclerosis using a Kinect-based system: randomized controlled trial. JMIR Serious Games. 2(2). https://doi.org/10.2196/games.2933Se1222Adamovich, S. V., Fluet, G. G., Tunik, E., & Merians, A. S. (2009). Sensorimotor training in virtual reality: A review. Neurorehabilitation, 25(1), 29-44. doi:10.3233/nre-2009-0497Lange, B., Flynn, S., Proffitt, R., Chang, C.-Y., & «Skip» Rizzo, A. (2010). Development of an Interactive Game-Based Rehabilitation Tool for Dynamic Balance Training. Topics in Stroke Rehabilitation, 17(5), 345-352. doi:10.1310/tsr1705-345Lozano, J. A., Montesa, J., Juan, M. C., Alcañiz, M., Rey, B., Gil, J., … Morganti, F. (2005). VR-Mirror: A Virtual Reality System for Mental Practice in Post-Stroke Rehabilitation. Lecture Notes in Computer Science, 241-251. doi:10.1007/11536482_23Lange, B. S., Requejo, P., Flynn, S. M., Rizzo, A. A., Valero-Cuevas, F. J., Baker, L., & Winstein, C. (2010). The Potential of Virtual Reality and Gaming to Assist Successful Aging with Disability. Physical Medicine and Rehabilitation Clinics of North America, 21(2), 339-356. doi:10.1016/j.pmr.2009.12.007Wuang, Y.-P., Chiang, C.-S., Su, C.-Y., & Wang, C.-C. (2011). Effectiveness of virtual reality using Wii gaming technology in children with Down syndrome. Research in Developmental Disabilities, 32(1), 312-321. doi:10.1016/j.ridd.2010.10.002Chang, Y.-J., Chen, S.-F., & Huang, J.-D. (2011). A Kinect-based system for physical rehabilitation: A pilot study for young adults with motor disabilities. Research in Developmental Disabilities, 32(6), 2566-2570. doi:10.1016/j.ridd.2011.07.002Da GamaAChavezTFigueiredoLTeichriebVPoster: improving motor rehabilitation process through a natural interaction based system using kinect sensor, IEEE Symposium on 3D User Interfaces 2012: 145-1462012IEEE Symposium on 3D User InterfacesMar 4-5Costa Mesa, CABaram, Y., & Miller, A. (2006). Virtual reality cues for improvement of gait in patients with multiple sclerosis. Neurology, 66(2), 178-181. doi:10.1212/01.wnl.0000194255.82542.6bFulk, G. D. (2005). Locomotor Training and Virtual Reality-based Balance Training for an Individual with Multiple Sclerosis. Journal of Neurologic Physical Therapy, 29(1), 34-42. doi:10.1097/01.npt.0000282260.59078.e4Lozano-QuilisJAAlbiol-PerezSGil-GomezHPalaciosGFardoumHMGil-GomezJAMashatASVirtual reality system for multiple sclerosis rehabilitation using KINECT2013International Conference on Pervasive Computing Technologies for Healthcare (PervasiveHealth)May 5-8Venice, Italy366369Van Hedel, H. J., Wirz, M., & Dietz, V. (2005). Assessing walking ability in subjects with spinal cord injury: Validity and reliability of 3 walking tests. Archives of Physical Medicine and Rehabilitation, 86(2), 190-196. doi:10.1016/j.apmr.2004.02.010Podsiadlo, D., & Richardson, S. (1991). The Timed «Up & Go»: A Test of Basic Functional Mobility for Frail Elderly Persons. Journal of the American Geriatrics Society, 39(2), 142-148. doi:10.1111/j.1532-5415.1991.tb01616.xSteffen, T. M., Hacker, T. A., & Mollinger, L. (2002). Age- and Gender-Related Test Performance in Community-Dwelling Elderly People: Six-Minute Walk Test, Berg Balance Scale, Timed Up & Go Test, and Gait Speeds. Physical Therapy, 82(2), 128-137. doi:10.1093/ptj/82.2.128Gil-GomezJASEQ: Suitability Evaluation Questionnaire for Virtual Rehabilitation systems2013International Conference on Pervasive Computing Technologies for Healthcare (PervasiveHealth)2013Venice, Italy33533
Influence of wiring cost on the large-scale architecture of human cortical connectivity
In the past two decades some fundamental properties of cortical connectivity have been discovered: small-world structure, pronounced hierarchical and modular organisation, and strong core and rich-club structures. A common assumption when interpreting results of this kind is that the observed structural properties are present to enable the brain's function. However, the brain is also embedded into the limited space of the skull and its wiring has associated developmental and metabolic costs. These basic physical and economic aspects place separate, often conflicting, constraints on the brain's connectivity, which must be characterized in order to understand the true relationship between brain structure and function. To address this challenge, here we ask which, and to what extent, aspects of the structural organisation of the brain are conserved if we preserve specific spatial and topological properties of the brain but otherwise randomise its connectivity. We perform a comparative analysis of a connectivity map of the cortical connectome both on high- and low-resolutions utilising three different types of surrogate networks: spatially unconstrained (‘random’), connection length preserving (‘spatial’), and connection length optimised (‘reduced’) surrogates. We find that unconstrained randomisation markedly diminishes all investigated architectural properties of cortical connectivity. By contrast, spatial and reduced surrogates largely preserve most properties and, interestingly, often more so in the reduced surrogates. Specifically, our results suggest that the cortical network is less tightly integrated than its spatial constraints would allow, but more strongly segregated than its spatial constraints would necessitate. We additionally find that hierarchical organisation and rich-club structure of the cortical connectivity are largely preserved in spatial and reduced surrogates and hence may be partially attributable to cortical wiring constraints. In contrast, the high modularity and strong s-core of the high-resolution cortical network are significantly stronger than in the surrogates, underlining their potential functional relevance in the brain
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