724 research outputs found

    A Split-Stem Lesion on Young Hybrid \u3ci\u3ePopulus\u3c/i\u3e Trees Caused by the Tarnished Plant Bug, \u3ci\u3eLygus Lineolaris\u3c/i\u3e (Hemiptera: [Heteroptera]: Miridae)

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    The tarnished plant bug, known principally as an agricultural pest, injures young hybrid Populus by feeding on the stems and meristems. Tarnished plant bug eggs, fungi associated with some lesions, and simple mechanical stimuli alone from feeding appeared not to cause lesion formation. Of 20 Populus hybrids tested in a clonal trial, four appeared to be consistently susceptible to lesion injury, with Populus nigra var. betulifolia x trichocarpa the most susceptible. Several clones showed high resistance in the trial but a few were susceptible in other plantings and in host preference tests when caged with tarnished plant bugs. Lesions diminished tenfold on Populus where horseweed, the insect\u27s principal wild host, grew along with susceptible poplars. The tarnished plant bug can be suppressed by ultra-low volume pesticides and cultural manipulation of understory vegetation

    Sensory Plasticity in Human Motor Learning.

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    There is accumulating evidence from behavioral, neurophysiological, and neuroimaging studies that the acquisition of motor skills involves both perceptual and motor learning. Perceptual learning alters movements, motor learning, and motor networks of the brain. Motor learning changes perceptual function and the sensory circuits of the brain. Here, we review studies of both human limb movement and speech that indicate that plasticity in sensory and motor systems is reciprocally linked. Taken together, this points to an approach to motor learning in which perceptual learning and sensory plasticity have a fundamental role

    Somatosensory Precision in Speech Production

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    SummarySpeech production is dependent on both auditory and somatosensory feedback [1–3]. Although audition may appear to be the dominant sensory modality in speech production, somatosensory information plays a role that extends from brainstem responses to cortical control [4–6]. Accordingly, the motor commands that underlie speech movements may have somatosensory as well as auditory goals [7]. Here we provide evidence that, independent of the acoustics, somatosensory information is central to achieving the precision requirements of speech movements. We were able to dissociate auditory and somatosensory feedback by using a robotic device that altered the jaw's motion path, and hence proprioception, without affecting speech acoustics. The loads were designed to target either the consonant- or vowel-related portion of an utterance because these are the major sound categories in speech. We found that, even in the absence of any effect on the acoustics, with learning subjects corrected to an equal extent for both kinds of loads. This finding suggests that there are comparable somatosensory precision requirements for both kinds of speech sounds. We provide experimental evidence that the neural control of stiffness or impedance—the resistance to displacement—provides for somatosensory precision in speech production [8–10]

    Speech motor learning changes the neural response to both auditory and somatosensory signals

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    International audienceIn the present paper, we present evidence for the idea that speech motor learning is accompanied by changes to the neural coding of both auditory and somatosensory stimuli. Participants in our experiments undergo adaptation to altered auditory feedback, an experimental model of speech motor learning which like visuo-motor adaptation in limb movement, requires that participants change their speech movements and associated somatosensory inputs to correct for systematic real-time changes to auditory feedback. We measure the sensory effects of adaptation by examining changes to auditory and somatosensory event-related responses. We find that adaptation results in progressive changes to speech acoustical outputs that serve to correct for the perturbation. We also observe changes in both auditory and somatosensory event-related responses that are correlated with the magnitude of adaptation. These results indicate that sensory change occurs in conjunction with the processes involved in speech motor adaptation

    Somatosensory Event-related Potentials from Orofacial Skin Stretch Stimulation

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    International audienceCortical processing associated with orofacial somatosensory function in speech has received limited experimental attention due to the difficulty of providing precise and controlled stimulation. This article introduces a technique for recording somatosensory event-related potentials (ERP) that uses a novel mechanical stimulation method involving skin deformation using a robotic device. Controlled deformation of the facial skin is used to modulate kinesthetic inputs through excitation of cutaneous mechanoreceptors. By combining somatosensory stimulation with electroencephalographic recording, somatosensory evoked responses can be successfully measured at the level of the cortex. Somatosensory stimulation can be combined with the stimulation of other sensory modalities to assess multisensory interactions. For speech, orofacial stimulation is combined with speech sound stimulation to assess the contribution of multi-sensory processing including the effects of timing differences. The ability to precisely control orofacial somatosensory stimulation during speech perception and speech production with ERP recording is an important tool that provides new insight into the neural organization and neural representations for speech. Video Link The video component of this article can be found at http://www.jove.com/video/53621

    Neural correlates of auditory-somatosensory interaction in speech perception

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    International audienceSpeech perception is known to rely on both auditory and visual information. However, sound specific somatosensory input has been shown also to influence speech perceptual processing (Ito et al., 2009). In the present study we addressed further the relationship between somatosensory information and speech perceptual processing by addressing the hypothesis that the temporal relationship between orofacial movement and sound processing contributes to somatosensory-auditory interaction in speech perception. We examined the changes in event-related potentials in response to multisensory synchronous (simultaneous) and asynchronous (90 ms lag and lead) somatosensory and auditory stimulation compared to individual unisensory auditory and somatosensory stimulation alone. We used a robotic device to apply facial skin somatosensory deformations that were similar in timing and duration to those experienced in speech production. Following synchronous multisensory stimulation the amplitude of the event-related potential was reliably different from the two unisensory potentials. More importantly, the magnitude of the event-related potential difference varied as a function of the relative timing of the somatosensory-auditory stimulation. Event-related activity change due to stimulus timing was seen between 160-220 ms following somatosensory onset, mostly around the parietal area. The results demonstrate a dynamic modulation of somatosensory-auditory convergence and suggest the contribution of somatosensory information for speech processing process is dependent on the specific temporal order of sensory inputs in speech production

    The impact of weather on COVID-19 pandemic

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    Rising temperature levels during spring and summer are often argued to enable lifting of strict containment measures even in the absence of herd immunity. Despite broad scholarly interest in the relationship between weather and coronavirus spread, previous studies come to very mixed results. To contribute to this puzzle, the paper examines the impact of weather on the COVID-19 pandemic using a unique granular dataset of over 1.2 million daily observations covering over 3700 counties in nine countries for all seasons of 2020. Our results show that temperature and wind speed have a robust negative effect on virus spread after controlling for a range of potential confounding factors. These effects, however, are substantially larger during mealtimes, as well as in periods of high mobility and low containment, suggesting an important role for social behaviour

    The use of prolog in the realisation of digital transfer functions

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    Systems characterised by general graphs are very flexible because of a given application they offer a great number of degrees of freedom and consequently a great possibility of choice to the designer. This can become a drawback in practice when myriads of cases have to be examined analytically and most of them rejected for a variety of heterogeneous reasons. For such design problems, it appears that logic programming languages are ideally suited because they can implement the heterogeneous rules which describe the desired system in a natural way. An application of the Prolog language to the design of active RC biquad circuits investigated by Mouly in his doctoral thesis illustrates the advantages of such a rule-based approach.<br /

    Human jaw movement in mastication and speech.

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    Summary-The study of jaw movement in humans is a primary source of information about the relationship between voluntary movement and more primitive motor functions. This study focused on the geometric form of the velocity function, as measured by linear voltage displacement transducer. Movement amplitudes, maximum velocities and durations were greater in mastication than in speech. Nevertheless, there were detailed similarities in the shape of the normalized velocity functions. In jaw-closing movements, the normalized functions were similar in form over differences in rate, movement amplitude (speech movements) and the compliance of the bolus (mastication). In opening movements, the functions for mastication and speech were again similar over differences in amplitude and compliance. However, they differed in shape for fast and slow movements. Normalized acceleration and deceleration durations were approximately equal in rapid movements, whereas, for slower movements, deceleration took substantially longer than acceleration

    Monitoring of genetically modified food on the Czech food market and a cross-country comparison

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    The presence of genetically modified organisms (GMOs) was analysed in food samples from the Czech food markets. Four different types of food samples (soya beans, soya bean products, maize flour, and rice) were collected at twelve places in four terms in the years 2008–2013. It represents a total 1152 food samples. Soya and maize were chosen, because these are the major transgenic crops grown worldwide. Increased cultivation of GM rice in China, India, Indonesia, and the Philippines has been observed. Polymerase chain reaction-based methods were applied to detect GMOs. GMOs were detected in 107 samples (9.3%). The results show that in food from the Czech food market GMOs mainly in maize flour and rice were found. GM maize was detected in 63 (21.9%) maize flour samples. Maize lines MON810, NK603, and Bt176 were detected in 14 (22%), 9 (14%), and 1 (1.6%) maize flour samples, respectively. Unauthorised GM rice was detected in 39 (13.5%) rice samples. Unauthorised rice Bt63 was detected in one sample of rice. Roundup Ready soya was detected in 4 (1.4%) soya bean samples and in 1 (0.35%) soya product sample. These results were compared with results of the world´s studies
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