4,677 research outputs found
Integrating visual and tactile information in the perirhinal cortex
By virtue of its widespread afferent projections, perirhinal cortex is thought to bind polymodal information into abstract object-level representations. Consistent with this proposal, deficits in cross-modal integration have been reported after perirhinal lesions in nonhuman primates. It is therefore surprising that imaging studies of humans have not observed perirhinal activation during visual–tactile object matching. Critically, however, these studies did not differentiate between congruent and incongruent trials. This is important because successful integration can only occur when polymodal information indicates a single object (congruent) rather than different objects (incongruent). We scanned neurologically intact individuals using functional magnetic resonance imaging (fMRI) while they matched shapes. We found higher perirhinal activation bilaterally for cross-modal (visual–tactile) than unimodal (visual–visual or tactile–tactile) matching, but only when visual and tactile attributes were congruent. Our results demonstrate that the human perirhinal cortex is involved in cross-modal, visual–tactile, integration and, thus, indicate a functional homology between human and monkey perirhinal cortices
Accelerator measurement of the energy spectra of neutrons emitted in the interaction of 3-GeV protons with several elements
The application of time of flight techniques for determining the shapes of the energy spectra of neutrons between 20 and 400 MeV is discussed. The neutrons are emitted at 20, 34, and 90 degrees in the bombardment of targets by 3 GeV protons. The targets used are carbon, aluminum, cobalt, and platinum with cylindrical cross section. Targets being bombarded are located in the internal circulating beam of a particle accelerator
A Study of Null Effects for the Use of Transcranial Direct Current Stimulation (tDCS) in Adults With and Without Reading Impairment
There is evidence to support the hypothesis that the delivery of anodal transcranial direct current stimulation (tDCS) to the left temporoparietal junction can enhance performance on reading speed and reading accuracy (Costanzo et al., 2016b; Heth & Lavidor, 2015). Here, we explored whether we could demonstrate similar effects in adults with and without reading impairments. Method: Adults with (N = 33) and without (N = 29) reading impairment were randomly assigned to anodal or sham stimulation conditions. All individuals underwent a battery of reading assessments pre and post stimulation. The stimulation session involved 15 min of anodal/sham stimulation over the left temporoparietal junction while concurrently completing a computerized nonword segmentation task known to activate the temporoparietal junction. Results: There were no conclusive findings that anodal stimulation impacted reading performance for skilled or impaired readers. Conclusions: While tDCS may provide useful gains on reading performance in the paediatric population, much more work is needed to establish the parameters under which such findings would transfer to adult populations. The documentation, reporting, and interpreting of null effects of tDCS are immensely important to a field that is growing exponentially with much uncertainty
Global water level variability observed after the Hunga Tonga-Hunga Ha'apai volcanic tsunami of 2022
The eruption of the Hunga Tonga-Hunga Ha'apai volcano on 15 January 2022 provided a rare opportunity to understand global tsunami
impacts of explosive volcanism and to evaluate future hazards, including
dangers from “volcanic meteotsunamis” (VMTs) induced by the atmospheric
shock waves that followed the eruption. The propagation of the volcanic and
marine tsunamis was analyzed using globally distributed 1 min measurements
of air pressure and water level (WL) (from both tide gauges and deep-water
buoys). The marine tsunami propagated primarily throughout the Pacific,
reaching nearly 2 m at some locations, though most Pacific locations
recorded maximums lower than 1 m. However, the VMT resulting from the
atmospheric shock wave arrived before the marine tsunami and propagated
globally, producing water level perturbations in the Indian Ocean, the
Mediterranean, and the Caribbean. The resulting water level response of many
Pacific Rim gauges was amplified, likely related to wave interaction with
bathymetry. The meteotsunami repeatedly boosted tsunami wave energy as it
circled the planet several times. In some locations, the VMT was amplified
by as much as 35-fold relative to the inverse barometer due to near-Proudman
resonance and topographic effects. Thus, a meteotsunami from a larger
eruption (such as the Krakatoa eruption of 1883) could yield atmospheric
pressure changes of 10 to 30 mb, yielding a 3–10 m near-field tsunami that
would occur in advance of (usually) larger marine tsunami waves, posing
additional hazards to local populations. Present tsunami warning systems do
not consider this threat.</p
A Measurement of the Angular Power Spectrum of the CMB from l = 100 to 400
We report on a measurement of the angular spectrum of the CMB between
and made at 144 GHz from Cerro Toco in the
Chilean altiplano. When the new data are combined with previous data at 30 and
40 GHz, taken with the same instrument observing the same section of sky, we
find: 1) a rise in the angular spectrum to a maximum with K at and a fall at , thereby localizing the peak
near ; and 2) that the anisotropy at has the
spectrum of the CMB.Comment: 4 pages, 2 figures. Revised version; includes Ned Wright's postscript
fix. Accepted by ApJL. Website at http://physics.princeton.edu/~cmb
Breakfast and exercise contingently affect postprandial metabolism and energy balance in physically active males
The present study examined the impact of breakfast and exercise on postprandial metabolism, appetite and macronutrient balance.
A sample of twelve (blood variables n 11) physically active males completed four trials in a randomised, crossover design comprising a continued overnight fast followed by: (1) rest without breakfast (FR); (2) exercise without breakfast (FE); (3) breakfast consumption(1859 kJ) followed by rest (BR); (4) breakfast consumption followed by exercise (BE). Exercise was continuous, moderate-intensity running (expending approximately 2·9MJ of energy). The equivalent time was spent sitting during resting trials. A test drink (1500 kJ) was ingested on all trials followed 90 min later by an ad libitum lunch. The difference between the BR and FR trials in blood glucose time-averaged AUC following test drink consumption approached significance (BR: 4·33 (SEM 0·14) v. FR: 4·75 (SEM 0·16) mmol/l; P¼0·08); but it was not different between FR and FE (FE: 4·77 (SEM 0·14) mmol/l; P¼0·65); and was greater in BE (BE: 4·97 (SEM 0·13) mmol/l) v. BR(P¼0·012). Appetite following the test drink was reduced in BR v. FR (P¼0·006) and in BE v. FE (P¼0·029). Following lunch, the most positive energy balance was observed in BR and least positive in FE. Regardless of breakfast, acute exercise produced a less positive energy balance following ad libitum lunch consumption. Energy and fat balance is further reduced with breakfast omission. Breakfast improved the overall appetite responses to foods consumed later in the day, but abrogated the appetite suppressive effect of exercise
Galactic microwave emission at degree angular scales
We cross-correlate the Saskatoon Ka and Q-Band Cosmic Microwave Background
(CMB) data with different maps to quantify possible foreground contamination.
We detect a marginal correlation (2 sigma) with the Diffuse Infrared Background
Experiment (DIRBE) 240, 140 and 100 microm maps, but we find no significant
correlation with point sources, with the Haslam 408 MHz map or with the Reich
and Reich 1420 MHz map. The rms amplitude of the component correlated with
DIRBE is about 20% of the CMB signal. Interpreting this component as free-free
emission, this normalization agrees with that of Kogut et al. (1996a; 1996b)
and supports the hypothesis that the spatial correlation between dust and warm
ionized gas observed on large angular scales persists to smaller angular
scales. Subtracting this contribution from the CMB data reduces the
normalization of the Saskatoon power spectrum by only a few percent.Comment: Minor revisions to match published version. 14 pages, with 2 figures
included. Color figure and links at
http://www.sns.ias.edu/~angelica/foreground.htm
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