Synchronization to a bouncing ball with a realistic motion trajectory

Daily music experience involves synchronizing movements in time with a perceived periodic beat. It has been established for over a century that beat synchronization is less stable for the visual than for the auditory modality. This auditory advantage of beat synchronization gives rise to the hypotheses that the neural and evolutionary mechanisms underlying beat synchronization are modality-specific. Here, however, we found that synchronization to a periodically bouncing ball with a realistic motion trajectory was not less stable than synchronization to an auditory metronome. This finding challenges the auditory advantage of beat synchronization, and has important implications for the understanding of the biological substrates of beat synchronization

Persistent fluctuations in stride intervals under fractal auditory stimulation

Copyright @ 2014 Marmelat et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Stride sequences of healthy gait are characterized by persistent long-range correlations, which become anti-persistent in the presence of an isochronous metronome. The latter phenomenon is of particular interest because auditory cueing is generally considered to reduce stride variability and may hence be beneficial for stabilizing gait. Complex systems tend to match their correlation structure when synchronizing. In gait training, can one capitalize on this tendency by using a fractal metronome rather than an isochronous one? We examined whether auditory cues with fractal variations in inter-beat intervals yield similar fractal inter-stride interval variability as isochronous auditory cueing in two complementary experiments. In Experiment 1, participants walked on a treadmill while being paced by either an isochronous or a fractal metronome with different variation strengths between beats in order to test whether participants managed to synchronize with a fractal metronome and to determine the necessary amount of variability for participants to switch from anti-persistent to persistent inter-stride intervals. Participants did synchronize with the metronome despite its fractal randomness. The corresponding coefficient of variation of inter-beat intervals was fixed in Experiment 2, in which participants walked on a treadmill while being paced by non-isochronous metronomes with different scaling exponents. As expected, inter-stride intervals showed persistent correlations similar to self-paced walking only when cueing contained persistent correlations. Our results open up a new window to optimize rhythmic auditory cueing for gait stabilization by integrating fractal fluctuations in the inter-beat intervals.Commission of the European Community and the Netherlands Organisation for Scientific Research

Cue properties change timing strategies in group movement synchronisation

To maintain synchrony in group activities, each individual within the group must continuously correct their movements to remain in time with the temporal cues available. Cues might originate from one or more members of the group. Current research suggests that when synchronising movements, individuals optimise their performance in terms of minimising variability of timing errors (asynchronies) between external cues and their own movements. However, the cost of this is an increase in the timing variability of their own movements. Here we investigate whether an individual’s timing strategy changes according to the task, in a group scenario. To investigate this, we employed a novel paradigm that positioned six individuals to form two chains with common origin and termination on the circumference of a circle. We found that participants with access to timing cues from only one other member used a strategy to minimise their asynchrony variance. In contrast, the participant at the common termination of the two chains, who was required to integrate timing cues from two members, used a strategy that minimised movement variability. We conclude that humans are able to flexibly switch timekeeping strategies to maintain task demands and thus optimise the temporal performance of their movements

Synchrony and Physiological Arousal Increase Cohesion and Cooperation in Large Naturalistic Groups

Separate research streams have identified synchrony and arousal as two factors that might contribute to the effects of human rituals on social cohesion and cooperation. But no research has manipulated these variables in the field to investigate their causal – and potentially interactive – effects on prosocial behaviour. Across four experimental sessions involving large samples of strangers, we manipulated the synchronous and physiologically arousing affordances of a group marching task within a sports stadium. We observed participants’ subsequent movement, grouping, and cooperation via a camera hidden in the stadium’s roof. Synchrony and arousal both showed main effects, predicting larger groups, tighter clustering, and more cooperative behaviour in a free-rider dilemma. However, synchrony and arousal interacted on measures of clustering and cooperation: such that synchrony only encouraged closer clustering — and encouraged greater cooperation—when paired with physiological arousal. The research has implications for understanding the nature and co-occurrence of synchrony and physiological arousal in rituals around the world. It also represents the first use of real-time spatial tracking as a precise and naturalistic method of simulating collective rituals

Position and momentum mapping of vibrations in graphene nanostructures in the electron microscope

Propagating atomic vibrational waves, phonons, rule important thermal, mechanical, optoelectronic and transport characteristics of materials. Thus the knowledge of phonon dispersion, namely the dependence of vibrational energy on momentum is a key ingredient to understand and optimize the material's behavior. However, despite its scientific importance in the last decade, the phonon dispersion of a freestanding monolayer of two dimensional (2D) materials such as graphene and its local variations has still remained elusive because of experimental limitations of vibrational spectroscopy. Even though electron energy loss spectroscopy (EELS) in transmission has recently been shown to probe the local vibrational charge responses, these studies are yet limited to polar materials like boron nitride or oxides, in which huge signals induced by strong dipole moments are present. On the other hand, measurements on graphene performed by inelastic x-ray (neutron) scattering spectroscopy or EELS in reflection do not have any spatial resolution and require large microcrystals. Here we provide a new pathway to determine the phonon dispersions down to the scale of an individual freestanding graphene monolayer by mapping the distinct vibration modes for a large momentum transfer. The measured scattering intensities are accurately reproduced and interpreted with density functional perturbation theory (DFPT). Additionally, a nanometre-scale mapping of selected momentum (q) resolved vibration modes using graphene nanoribbon structures has enabled us to spatially disentangle bulk, edge and surface vibrations

A salting out and resin procedure for extracting Schistosoma mansoni DNA from human urine samples

Submitted by Nuzia Santos ([email protected]) on 2012-09-27T14:31:36Z No. of bitstreams: 1 36.2010.pdf: 789056 bytes, checksum: 0a4282ac34d4c6aef08223da45e0f126 (MD5)Made available in DSpace on 2012-09-27T14:31:36Z (GMT). No. of bitstreams: 1 36.2010.pdf: 789056 bytes, checksum: 0a4282ac34d4c6aef08223da45e0f126 (MD5) Previous issue date: 2010Fundação Oswaldo Cruz. Laboratório de Esquistossomose. Belo Horizonte, MG, BrasilFundação Oswaldo Cruz. Laboratório de Imunologia Celular e Molecular. Belo Horizonte, MG, BrasilFundação Oswaldo Cruz. Laboratório de Imunologia Celular e Molecular. Belo Horizonte, MG, Brasil/ Universidade Federal de Ouro Preto. Escola de Farmácia. Laboratório de Pesquisas Clínicas. Ouro Preto, MG, BraziBackground: In this paper a simple and cheap salting out and resin (InstaGene matrix® resin - BioRad) DNA extraction method from urine for PCR assays is introduced. The DNA of the fluke Schistosoma mansoni was chosen as the target since schistosomiasis lacks a suitable diagnostic tool which is sensitive enough to detect low worm burden. It is well known that the PCR technique provides high sensitivity and specificity in detecting parasite DNA. Therefore it is of paramount importance to take advantage of its excellent performance by providing a simple to handle and reliable DNA extraction procedure, which permits the diagnosis of the disease in easily obtainable urine samples. Findings: The description of the extraction procedure is given. This extraction procedure was tested for reproducibility and efficiency in artificially contaminated human urine samples. The reproducibility reached 100%, showing positive results in 5 assay repetitions of 5 tested samples each containing 20 ng DNA/5 ml. The efficiency of the extraction procedure was also evaluated in a serial dilution of the original 20 ng DNA/5 ml sample. Detectable DNA was extracted when it was at a concentration of 1.28 pg DNA/mL, revealing the high efficiency of this procedure. Conclusions: This methodology represents a promising tool for schistosomiasis diagnosis utilizing a bio-molecular technique in urine samples which is now ready to be tested under field conditions and may be applicable to the diagnosis of other parasitic disease

Diagnostic Accuracy and Applicability of a PCR System for the Detection of Schistosoma mansoni DNA in Human Urine Samples from an Endemic Area

Schistosomiasis caused by Schistosoma mansoni, one of the most neglected human parasitoses in Latin America and Africa, is routinely confirmed by microscopic visualization of eggs in stool. The main limitation of this diagnostic approach is its lack of sensitivity in detecting individual low worm burdens and consequently data on infection rates in low transmission settings are little reliable. According to the scientific literature, PCR assays are characterized by high sensitivity and specificity in detecting parasite DNA in biological samples. A simple and cost effective extraction method for DNA of Schistosoma mansoni from urine samples in combination with a conventional PCR assay was developed and applied in an endemic area. This urine based PCR system was tested for diagnostic accuracy among a population of a small village in an endemic area, comparing it to a reference test composed of three different parasitological techniques. The diagnostic parameters revealed a sensitivity of 100%, a specificity of 91.20%, positive and negative predictive values of 86.25% and 100%, respectively, and a test accuracy of 94.33%. Further statistical analysis showed a k index of 0.8806, indicating an excellent agreement between the reference test and the PCR system. Data obtained from the mouse model indicate the infection can be detected one week after cercariae penetration, opening a new perspective for early detection and patient management during this stage of the disease. The data indicate that this innovative PCR system provides a simple to handle and robust diagnostic tool for the detection of S. mansoni DNA from urine samples and a promising approach to overcome the diagnostic obstacles in low transmission settings. Furthermore the principals of this molecular technique, based on the examination of human urine samples may be useful for the diagnosis of other neglected tropical diseases that can be detected by trans-renal DNA

Confocal Laser Scanning Microscopy for Detection of Schistosoma mansoni Eggs in the Gut of Mice

Background: The gold standard for diagnosing Schistosoma mansoni infections is the detection of eggs from stool or biopsy specimens. The viability of collected eggs can be tested by the miracidium hatching procedure. Direct detection methods are often limited in patients with light or early infections, whereas serological tests and PCR methods fail to differentiate between an inactive and persistent infection and between schistosomal species. Recently, confocal laser scanning microscopy (CLSM) has been introduced as a diagnostic tool in several fields of medicine. In this study we evaluated CLSM for the detection of viable eggs of S. mansoni directly within the gut of infected mice. Methodology/Principal Findings: The confocal laser scanning microscope used in this study is based on the Heidelberg Retina Tomograph II scanning laser system in combination with the Rostock Cornea Module (image modality 1) or a rigid endoscope (image modality 2). Colon sections of five infected mice were examined with image modalities 1 and 2 for schistosomal eggs. Afterwards a biopsy specimen was taken from each colon section and examined by bright-field microscopy. Visualised eggs were counted and classified in terms of viability status. Conclusions/Significance: We were able to show that CLSM visualises eggs directly within the gut and permits discrimination of schistosomal species and determination of egg viability. Thus, CLSM may be a suitable non-invasive too

Chronic allergen challenge induces bronchial mast cell accumulation in BALB/c but not C57BL/6 mice and is independent of IL-9

As genetically engineered mutant mice deficient in single genes are usually generated on a C57BL/6 background, to study mast cell trafficking in mutant mice, we initially investigated whether mast cells accumulated in bronchi in C57BL/6 mice challenged with OVA allergen acutely or chronically for 1 to 3 months. The total number of bronchial mast cells were quantitated using toluidine blue staining in airways of different sizes, i.e. , small (<90 µm), medium (90–155 µm), or large (>150 µm) airways. Non-OVA challenged and acute OVA challenged mice (C57BL/6 and BALB/c) had no detectable bronchial mast cells. Chronic OVA challenge in BALB/c mice for 1 or 3 months induced a significant increase in the number of bronchial mast cells in small-, medium-, and large-sized airways but minimal change in the number of bronchial mast cells in C57BL/6 mice. Both BALB/c and C57BL/6 mice developed significant lung eosinophilia following acute or chronic OVA challenge. Studies of IL-9-deficient mice on a BALB/c background demonstrated a significant increase in the number of bronchial mast cells in IL-9-deficient mice suggesting that IL-9 was not required for the bronchial accumulation of mast cells. Overall, these studies demonstrate that the chronic OVA challenge protocol we have utilized in BALB/c mice provides a model to study the mechanism of bronchial mast cell accumulation and that bronchial mast cell accumulation in chronic OVA challenged mice is independent of IL-9 in this model