111 research outputs found
A MULTIMEDIA MODEL FOR THE EVALUATION OF ENVIRONMENTAL BEHAVIOR OF DIOXINS
Joint Research on Environmental Science and Technology for the Eart
Effects of simultaneously performed dual-task training with aerobic exercise and working memory training on cognitive functions and neural systems in the elderly
Working memory (WM) training (WMT), aerobic exercise training (AET), and dual-task training improve cognitive functions and alter neural systems in older adults. In particular, the effects have been investigated of dual-task training that combines a walking or standing activity (balance exercise) simultaneously performed with cognitive training (which is ecologically difficult for the elderly). In this study, we investigated the effects of simultaneously performed dual-task training incorporating both AET and WMT (SDAEWMT), using a recumbent ergocycle bicycle and a WMT program that provided a portable console and made the training ecologically easy for the elderly. Older adults ( years old) participated in 3 months of SDAEWMT, WMT, or AET after random allocation, and the effects of SDAEWMT were compared with those of WMT and AET. Prior to and after training, all the subjects underwent cognitive testing, magnetic resonance imaging (MRI) involving diffusion tensor imaging (DTI), and functional MRI during performance of an N-back WM task. SDAEWMT improved executive function (performance of a frontal assessment battery); however, there was no evidence of broader transfer effects or enhanced learning with WMT. SDAEWMT resulted in mean diffusivity changes in brain areas involving the dopaminergic system, suggesting that neural tissue changes occurred in these areas. SDAEWMT also resulted in an increase in brain activity during the 2-back working memory task in brain areas involved in attentional reorientation. These results suggest that SDAEWMT is effective for improving cognitive functions and inducing beneficial neural changes in older adults
Effects of image lag on real-time target tracking in radiotherapy
There is a concern that image lag may reduce accuracy of real-time target tracking in radiotherapy. This study was performed to investigate influence of image lag on the accuracy of target tracking in radiotherapy. Fluoroscopic image: were obtained using a direct type of dynamic flat-panel detector (FPD) system under conditions of target tracking during radiotherapy. The images continued to be read out after X-irradiations and cutoff, and image lag properties in the system were then determined. Subsequently, a tungsten materials plate with a precision edge was mounted on to a motor control device, which provided a constant velocity. The plate was moved into the center of the detector at movement rate of 1 and 20 mm/s, covering lung tumor movement of normal breathing, and MTF and profile curves were measured on the edges covering and uncovering the detector. A lung tumor with blurred edge due to image lag was simulated using the results and then superimposed on breathing chest radiographs of a patient. The moving target with and without image lag was traced using a template-matching technique. In the results, the target could be traced within a margin for error ii external radiotherapy. The results indicated that there was no effect of image lag on target tracking in usual breathing speed in a radiotherapy situation. Further studies are required to investigate influence by the other factors, such a: exposure dose, target size and shape, imaging rate, and thickness of a patient\u27s body. © 2010 SPIE
Effects of time-compressed speech training on multiple functional and structural neural mechanisms involving the left superior temporal gyrus
Time-compressed speech is an artificial form of rapidly presented speech. Training with time-compressed speech (TCSSL) in a second language leads to adaptation toward TCSSL. Here, we newly investigated the effects of 4 weeks of training with TCSSL on diverse cognitive functions and neural systems using the fractional amplitude of spontaneous low-frequency fluctuations (fALFF), resting-state functional connectivity (RSFC) with the left superior temporal gyrus (STG), fractional anisotropy (FA), and regional gray matter volume (rGMV) of young adults by magnetic resonance imaging. There were no significant differences in change of performance of measures of cognitive functions or second language skills after training with TCSSL compared with that of the active control group. However, compared with the active control group, training with TCSSL was associated with increased fALFF, RSFC, and FA and decreased rGMV involving areas in the left STG. These results lacked evidence of a far transfer effect of time-compressed speech training on a wide range of cognitive functions and second language skills in young adults. However, these results demonstrated effects of time-compressed speech training on gray and white matter structures as well as on resting-state intrinsic activity and connectivity involving the left STG, which plays a key role in listening comprehension
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Effects of training of shadowing and reading aloud of second language on working memory and neural systems
Shadowing and reading aloud both involve multiple complex cognitive processes, and both are considered effective methods for second-language learning. The working memory system, particularly the phonological loop, has been suggested to be involved in shadowing and reading aloud. The purpose of this study was to investigate the effects of a 4-week intensive adaptive training including shadowing and reading aloud of second language on working-memory capacity, regional gray matter volume (rGMV), and functional activation related to the n-back working-memory task in young adults. The results showed that compared with the training groups without speaking (listening to compressed speech and active control involving the second language), the training groups with speaking (shadowing and reading aloud) showed a tendency for greater test-retest increases in digit-span scores, and significantly greater test-retest decreases in N-back task reaction time (increase in working memory performance). Imaging analyses revealed compared with the active control group, shadowing group exhibited decreases in rGMV and brain activity during the working memory task (2-back task), in the left cerebellum and reading group exhibited decreases in them in the right anterior insula. These regions are parts of the phonological loop, suggesting the presence of training-induced neural plasticity in these neurocognitive mechanisms
Monitoring the Size and Flux Density of Sgr A* during the Active State in 2019 with East Asian VLBI Network
This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).In this work, we studied the Galactic Center supermassive black hole (SMBH), Sagittarius A* (Sgr A∗
), with the KVN and VERA Array (KaVA)/East Asian VLBI Network (EAVN) monitoring observations. Especially in 13 May 2019, Sgr A∗ experienced an unprecedented bright near infra-red (NIR) flare; so, we find a possible counterpart at 43 GHz (7 mm). As a result, a large temporal variation of the flux density at the level ∼15.4%, with the highest flux density of 2.04 Jy, is found on 11 May 2019. Interestingly, the intrinsic sizes are also variable, and the area and major-axis size show marginal correlation with flux density with ≳2 . Thus, we interpret that the emission region at 43 GHz follows the larger-when-brighter relation in 2019. The possible origins are discussed with an emergence of a weak jet/outflow component and the position angle change of the rotation axis of the accretion disk in time. © 2023 by the authors. Licensee MDPI, Basel, Switzerland.The work at the IAA-CSIC is supported in part by the Spanish Ministerio de Economía y Competitividad (grants AYA2016-80889-P and PID2019-108995GB-C21), the Consejería de Economía, Conocimiento, Empresas y Universidad of the Junta de Andalucía (grant P18-FR-1769), the Consejo Superior de Investigaciones Científicas (grant 2019AEP112), and the State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709). This work was also supported by JSPS KAKENHI Grant Numbers JP18K13594, and MEXT as “Program for Promoting Researches on the Supercomputer Fugaku” (Toward a unified view of the universe: from large scale structures to planets, JPMXP1020200109) (T.K). Numerical computations were in part carried out on Cray XC50 at Center for Computational Astrophysics, National Astronomical Observatory of Japan. This work was supported by Brain Pool Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (2019H1D3A1A01102564).With funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (CEX2021-001131-S).Peer reviewe
Effects of time-compressed speech training on multiple functional and structural neural mechanisms involving the left superior temporal gyrus
Time-compressed speech is an artificial form of rapidly presented speech.
Training with time compressed speech in a second language leads to adaptation toward
time-compressed speech in a second language and toward time compressed speech in
different languages. However, the effects of training with time-compressed speech of a
second language (TCSSL) on diverse cognitive functions and neural mechanisms
beyond time compressed speech-related activation are unknown. We investigated the
effects of 4 weeks of training with TCSSL on the fractional amplitude of spontaneous
low-frequency fluctuations (fALFF) of 0.01–0.08 Hz, resting-state functional
connectivity (RSFC) with the left superior temporal gyrus (STG), fractional anisotropy
(FA), and regional gray matter volume (rGMV) of young adults by magnetic resonance
imaging. There were no significant differences in change of performance of measures of
cognitive functions or second language skills after training with TCSSL compared with
that of the active control group. However, compared with the active control group,
training with TCSSL was associated with increased fALFF, RSFC, and FA and
decreased rGMV involving areas in the left STG. These results lacked evidence of a far
transfer effect of time compressed speech training on a wide range of cognitive
functions and second language skills in young adults. However, these results
demonstrated effects of time compressed speech training on gray and white matter
structures as well as on resting-state intrinsic activity and connectivity involving the left
STG, which plays a key role in listening comprehension
Studying black holes on horizon scales with space-VLBI
The Event Horizon Telescope (EHT) recently produced the first horizon-scale image of a supermassive black hole. Expanding the array to include a 3-meter space telescope operating at >200 GHz enables mass measurements of many black holes, movies of black hole accretion flows, and new tests of general relativity that are impossible from the ground
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