6,591 research outputs found
The self-reference effect on memory in early childhood
The self-reference effect in memory is the advantage for information encoded about self, relative to other people. The early development of this effect was explored here using a concrete encoding paradigm. Trials comprised presentation of a self- or other-image paired with a concrete object. In Study 1, 4- to 6-year-old children (N = 53) were asked in each trial whether the child pictured would like the object. Recognition memory showed an advantage for self-paired objects. Study 2 (N = 55) replicated this finding in source memory. In Study 3 (N = 56), participants simply indicated object location. Again, recognition and source memory showed an advantage for self-paired items. These findings are discussed with reference to mechanisms that ensure information of potential self-relevance is reliably encoded
Structural MRI Correlates of Episodic Memory Processes in Parkinson's Disease Without Mild Cognitive Impairment.
BackgroundChanges in episodic memory are common early in Parkinson's disease (PD) and may be a risk factor for future cognitive decline. Although medial temporal lobe (MTL) memory and frontostriatal (FS) executive systems are thought to play different roles in distinct components of episodic memory impairment in PD, no study has investigated whether different aspects of memory functioning are differentially associated with MTL and FS volumes in nondemented patients without mild cognitive impairment (PD-woMCI).ObjectivesThe present study investigated MRI markers of different facets of memory functioning in 48 PD-woMCI patients and 42 controls.MethodsRegional volumes were measured in structures comprising the MTL and FS systems and then correlated with key indices of memory from the California Verbal Learning Test.ResultsIn PD-woMCI patients, memory was impaired only for verbal learning, which was not associated with executive, attention/working memory, or visuospatial functioning. Despite an absence of cortical atrophy, smaller right MTL volumes in patients were associated with poorer verbal learning, long delayed free recall, long delayed cued recall, and recognition memory hits and false positives. Smaller right pars triangularis (inferior frontal) volumes were also associated with poorer long delayed cued recall and recognition memory hits. These relationships were not found in controls.ConclusionsThe findings indicate that MTL volumes are sensitive to subtle changes in almost all facets of memory in PD-woMCI, whereas FS volumes are sensitive only to memory performances in cued-testing formats
Contaminant removal from enclosed atmospheres by regenerable adsorbents
A system for removing contaminants from spacecraft atmospheres was studied, which utilizes catalyst-impregnated activated carbon followed by in-situ regeneration by low-temperature catalytic oxidation of the adsorbed contaminants. Platinum was deposited on activated carbon by liquid phase impregnation with chloroplatinic acid, followed by drying and high-temperature reduction. Results were obtained for the seven selected spacecraft contaminants by means of three experimental test systems. The results indicate that the contaminants could be removed by oxidation with very little loss in adsorptive capacity. The advantages of a catalyst-impregnated carbon for oxidative regeneration are found to be significant enough to warrent its use
Increased resistance in splenectomized mice to a methylcholanthrene-induced tumour.
Prior splenectomy increased the resistance of BALB/c mice to a syngeneic methylcholanthrene-induced ascitic tumour inoculated i.p. The survival rate of splenectomized mice was 81-6% while those of normal and sham-operated controls were 11-5% and 20% respectively. The effect of splenectomy, however, was seen only within the dose range of 10(3) to 10(4) tumour cells. This effect of splenectomy was abolished by the transfer to mice of serum from tumour-bearing mice, and of spleen cells from normal donors, immediately after the inoculation of tumour cells. Cell-free ascitis fluid did not abolish the effect of splenectomy. The findings suggest that there is a subpopulation of spleen cells which produces a tumour growth enhancing factor which is found in the serum of tumour-bearing mice
Parallel HOP: A Scalable Halo Finder for Massive Cosmological Data Sets
Modern N-body cosmological simulations contain billions () of dark
matter particles. These simulations require hundreds to thousands of gigabytes
of memory, and employ hundreds to tens of thousands of processing cores on many
compute nodes. In order to study the distribution of dark matter in a
cosmological simulation, the dark matter halos must be identified using a halo
finder, which establishes the halo membership of every particle in the
simulation. The resources required for halo finding are similar to the
requirements for the simulation itself. In particular, simulations have become
too extensive to use commonly-employed halo finders, such that the
computational requirements to identify halos must now be spread across multiple
nodes and cores. Here we present a scalable-parallel halo finding method called
Parallel HOP for large-scale cosmological simulation data. Based on the halo
finder HOP, it utilizes MPI and domain decomposition to distribute the halo
finding workload across multiple compute nodes, enabling analysis of much
larger datasets than is possible with the strictly serial or previous parallel
implementations of HOP. We provide a reference implementation of this method as
a part of the toolkit yt, an analysis toolkit for Adaptive Mesh Refinement
(AMR) data that includes complementary analysis modules. Additionally, we
discuss a suite of benchmarks that demonstrate that this method scales well up
to several hundred tasks and datasets in excess of particles. The
Parallel HOP method and our implementation can be readily applied to any kind
of N-body simulation data and is therefore widely applicable.Comment: 29 pages, 11 figures, 2 table
Evaluation of techniques for removal of spacecraft contaminants from activated carbon
Alternative techniques for the regeneration of carbon contaminated with various spacecraft contaminants were evaluated. Four different modes of regeneration were evaluated: (1) thermal desorption via vacuum, (2) thermal desorption via nitrogen purge, (3) in-situ catalytic oxidation of adsorbed contaminants, and (4) in-situ non-catalytic oxidation of adsorbed contaminants
Comparing stakeholder attitudes toward white-tailed deer and rare plant management in Canaan Valley, West Virginia
Canaan Valley, West Virginia, USA provides habitat for many plants considered rare in West Virginia. The local white-tailed deer (Odocoileus virginianus Zimm.) are a popular attraction for visitors as well as resident and nonresident hunters. However, concerns exist over the impact of white-tailed deer herbivory on rare plant communities in the wetlands. We evaluated stakeholder attitudes regarding white-tailed deer management and rare plant conservation by mailing surveys to property owners in Canaan Valley and Tucker County, WV, and providing surveys to visitors at Canaan Valley State Park and National Wildlife Refuge. Individuals that had incurred crop damage were more likely to view the Canaan Valley population as overabundant while nonresident landowners placed higher values on the conservation of rare plants and plant communities in Canaan Valley. We found that hunters were more likely than nonhunters to support white-tailed deer management actions. Results of this survey may help managers to direct management and education goals toward actual rather than perceived stakeholder attitudes
The Birth of a Galaxy - III. Propelling reionisation with the faintest galaxies
Starlight from galaxies plays a pivotal role throughout the process of cosmic
reionisation. We present the statistics of dwarf galaxy properties at z > 7 in
haloes with masses up to 10^9 solar masses, using a cosmological radiation
hydrodynamics simulation that follows their buildup starting with their
Population III progenitors. We find that metal-enriched star formation is not
restricted to atomic cooling ( K) haloes, but can occur
in haloes down to masses ~10^6 solar masses, especially in neutral regions.
Even though these smallest galaxies only host up to 10^4 solar masses of stars,
they provide nearly 30 per cent of the ionising photon budget. We find that the
galaxy luminosity function flattens above M_UV ~ -12 with a number density that
is unchanged at z < 10. The fraction of ionising radiation escaping into the
intergalactic medium is inversely dependent on halo mass, decreasing from 50 to
5 per cent in the mass range . Using our galaxy
statistics in a semi-analytic reionisation model, we find a Thomson scattering
optical depth consistent with the latest Planck results, while still being
consistent with the UV emissivity constraints provided by Ly forest
observations at z = 4-6.Comment: 21 pages, 15 figures, 4 tables. Accepted in MNRA
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