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1.
Counts of nerve fibers in the brachium of the inferior colliculus in man from birth to 97 years (28 brains) revealed an average on the right of 168,311/mm2 and an average of 168,593/mm2 on the left. The total fiber population for each level studied averaged 350,562 for section A (immediately adjacent to the inferior colliculus), 452, 372 for section B (center of brachium), and 559,242 for section C (immediately adjacent to the medial geniculate body). These figures were averaged from brains whose ages ranged from 11 to 89 years. The area of the brachium, as well as its total fiber population, increased as the medial geniculate body was approached. This indicates that fibers were entering the brachium at various points along its course from the inferior colliculus to the medial geniculate body or were leaving in the reverse direction. A lower fiber density was found in infant brains, and a loss of nerve fibers was evident in the 91- and the 97-year-old specimens.  相似文献   

2.
We report an abnormally high residual dislocation density in aluminium in an Al/Ti/Al laminate annealed at 873 K for seven days. The residual dislocation density reaches 7.5 × 1014 m?2, higher than that in aluminum after severe plastic deformation processes such as accumulative roll bonding and high-pressure torsion. It is proposed that the high residual dislocation density may result from obstruction of the movement of TiAl3 nanoparticles by the grain boundary and Ti atoms conglomerating at vacancies distributed in the aluminium matrix at a high temperature for a sufficient time to allow a relatively stable crystal.  相似文献   

3.
We report the fabrication of Al/n-ZnO/p-Si/Al diode structures with a flower-like ZnO layer. The average grain size, microstrain and dislocation density in the ZnO layer were determined as 25?nm, 1.55?×?10?3 and 3.23?×?1013?cm?2, respectively. From absorption spectra, the optical band gap was found to be ~3.17?eV. A red shift was attributed to non-stoichiometry arising from Zn+2 ions substituting for oxygen vacancies. The ideality factor was determined as 1.55. The barrier height was calculated as 0.71?eV from I–V characteristics and 0.73?eV using the Norde plots.  相似文献   

4.
Gross inspection of 30 human brains (60 hemispheres) from patients without hearing impairment revealed the following configurations of gyri: one on left and two on right (14 of 30); two on left and two on right (11 of 30); one on left and one on right (3 of 30); two on left and one on right (1 of 30); and two on left and three on right (1 of 30). The last group has since been extended to include all combinations other than the first four and the proportions of these combinations appear to persist in larger tallies. Thirteen of the 30 brains displayed double gyri on the left while 25 had double gyri on the right. Seventeen of the 30 brains possessed a single gyrus on the left and four specimens had a single gyrus on the right. In general, the left side has a tendency to fewer gyral markings. The average cortical surface area on the left is 1198 mm2 compared to 1380 on the right.  相似文献   

5.
Abstract

In Si and Ge, the optical dispersion parameters (single-oscillator energy Eo , dispersion energy Ed and bond energy gap Eg developed by Wemple and DiDomenico, and Phillips) have been analysed in the temperature range 100-300 K using data obtained by Icenogle et al. Eo and Eg exhibit a very small temperature dependence in both materials. The thermal coefficients of the dispersion energy, dEd/dT, have opposite signs (Si, –41·9 × 10?4eVK?1; Ge, +37·7 × 10?4eVK?1).  相似文献   

6.
The Peierls stress of the a/2?110? screw dislocation belonging to the shuffle set is calculated for silicon using density functional theory. We have checked the effect of boundary conditions by using two models, the supercell method where one considers a periodic array of dislocations, and the cluster method where a single dislocation is embedded in a small cluster. The Peierls stress is underestimated with the supercell and overestimated with the cluster. These contributions have been calculated and the Peierls stress is determined in the range between 2.4?×?10?2 and 2.8?×?10?2?eV?Å?3. When moving, the dislocation follows the {111} plane going through a low energy metastable configuration and never follows the 100 plane, which includes a higher energy metastable core configuration.  相似文献   

7.
Neurophysiology and optical imaging studies in monkeys and functional magnetic resonance imaging (fMRI) studies in both monkeys and humans have localized clustered neural responses in inferotemporal cortex selective for images of biologically relevant categories, such as faces and limbs. Using higher resolution (1.5 mm voxels) fMRI scanning methods than past studies (3–5 mm voxels), we recently reported a network of multiple face- and limb-selective regions that neighbor one another in human ventral temporal cortex (Weiner and Grill-Spector, Neuroimage, 52(4):1559–1573, 2010) and lateral occipitotemporal cortex (Weiner and Grill-Spector, Neuroimage, 56(4):2183–2199, 2011). Here, we expand on three basic organization principles of high-level visual cortex revealed by these findings: (1) consistency in the anatomical location of functional regions, (2) preserved spatial relationship among functional regions, and (3) a topographic organization of face- and limb-selective regions in adjacent and alternating clusters. We highlight the implications of this structure in comparing functional brain organization between typical and atypical populations. We conclude with a new model of high-level visual cortex consisting of ventral, lateral, and dorsal components, where multimodal processing related to vision, action, haptics, and language converges in the lateral pathway.  相似文献   

8.
We report on the manifestation and interconnected photoluminescence and electron paramagnetic resonance responses in gadolinium oxide (Gd2O3) nanorods subjected to 80 MeV carbon ion irradiation. On increasing the irradiation fluence between 1 × 1011 and 3 × 1012 ions/cm2, the emission associated with neutral oxygen vacancies (VOx), positioned at ~350 nm, undergoes a steady increase compared to that associated with singly charged vacancies (VO+), located at ~414 nm. The enhancement of spin–spin relaxation time (τss) is ascribed to a substantial changeover from VO+ to VOx defects with irradiation, the former being recognized as the major contributor to paramagnetic centres. Interconnected luminescence and spin–spin relaxation could provide insight for making advanced nanophosphors and spin valve elements.  相似文献   

9.
Although it is key to improving acceptability, there is sparse scientific literature on the experience of humans as passengers in partially automated cars. The present study therefore investigated the influence of road type, weather conditions, traffic congestion level, vehicle speed, and human factors (e.g., trust in automated cars) on passenger comfort in an automated car classified as Level 3 according to the Society of Automotive Engineers (SAE). Participants were exposed to scenarios in which a character is driven by an SAE Level 3 automated car in different combinations of conditions (e.g., highway × heavy rain × very congested traffic × vehicle following prescribed speed). They were asked to rate their perceived comfort as if they were the protagonist. Results showed that comfort was negatively affected by driving in downtown (vs. highway), heavy rain, and congested traffic. Interaction analyses showed that reducing the speed of the vehicle improved comfort in these two last conditions, considered either individually or in combination. Cluster analysis revealed four profiles: trusting in automation, averse to speed reduction, risk averse, and mistrusting automation. These profiles were all influenced differently by the driving conditions, and corresponded to varying levels of trust in automated cars. This study suggests that optimizing comfort in automated cars should take account of both driving conditions and human profiles.  相似文献   

10.
Two Fe–Cu binary model alloys, Fe–0.3Cu and Fe–0.6Cu, were irradiated with fission neutrons at doses ranging from 4?×?10?6 to 0.16 dpa (displacements per atom) at ~573 K to investigate the formation of Cu precipitates and microstructural evolution. The Cu content only affected the formation of Cu precipitates and microvoids at low doses. In Fe–0.3Cu, the formation of microvoids and Cu precipitates initiated at doses of 1.2?×?10?4 and 4?×?10?5 dpa, respectively. On the other hand, the formation of microvoids started at a dose of 4?×?10?4 dpa in Fe–0.6Cu, and Cu precipitates were formed even after irradiation to 4?×?10?6 dpa. On further irradiation, the difference in the formation of Cu precipitates and microvoids was small. Microvoids grew with increasing irradiation dose up to 3?×?10?3 dpa in both alloys. Prominent aggregation of Cu atoms occurred upon irradiation from 3?×?10?3 to 1.6?×?10?2 dpa and the microvoids shrank. The Cu precipitates no longer grew, and microvoids nucleated and grew in the matrix above a dose of 1.6?×?10?2 dpa in both alloys. The present studies clearly reveal the relationships between the formation and growth of Cu precipitates and microvoids with irradiation dose.  相似文献   

11.
The effects of chronic novel stressors, for 21 days, on the behavior and the serotoninergic (5-HT) system in Sprague-Dawley (SD) and Wistar Kyoto (WKY) rats were studied. Open-field and forced-swim tests revealed a significantly greater behavioral depression in the WKY strain. SD rats showed a decrease in3H-DPAT binding to 5-HT1A receptors in the hippocampus, whereas WKY rats revealed an increase in3H-DPAT binding in the hippocampus and hypothalamus. Stress did not appear to alter the binding of3H-DPAT to 5-HT1A sites in the dorsal raphe or median raphe in either strains. SD rats revealed a modest increase in 5-HT transporter (5-HTT) sites in the cortex; WKY rats revealed a decrease in 5-HTT sites in the cortex and the hippocampus. Stress caused an increase in3H-CNIMI binding to 5-HTT sites in the dorsal and median raphe nuclei in both strains. The results suggest that the greater susceptibility to behavioral depression in WKY rats may account for the differential effects on 5HT1A sites as well as 5-HTT sites in limbic regions and cell body area as compared to SD rats.  相似文献   

12.
The present study was designed to investigate the effects of self-efficacy on weight loss utilizing self-control techniques. Subjects high and low in preexisting self-efficacy were randomly assigned to high or low manipulated self-efficacy groups in a 2 × 2 (preexisting self-efficacy × manipulated self-efficacy) factorial design. Preexisting self-efficacy was assessed using procedures employed byBandura and Adams (1977, Cognitive Therapy and Research, 1, 287–308). Selfefficacy was manipulated by having subjects attribute successful task performance to a previously unrecognized capacity for self-control. Subjects met in groups once a week for a total of 8 weeks and received a comprehensive weight control program within the context of self-control. Results indicated significant manipulated and preexisting × trials interactions with both the high manipulated and preexisting self-efficacy groups losing more weight over the 8 weeks than the low preexisting and manipulated groups. In addition, locus of control was predictive of weight loss, with internals tending to lose more weight than externals. Results are discussed in terms of Bandura's (1977, Psychological Review, 84, 191–215) theory of self-efficacy.  相似文献   

13.
The spatial distribution of europium-dihalide-type precipitates in KCl?:?KBr?:Eu2+ single crystals annealed at 200°C for long periods of time was determined by epifluorescence optical microscopy. Laue-type patterns and optical spectroscopy were used to test the degree of long-range ordering of the specimens and to monitor the precipitation during annealing, respectively. Precipitates smaller than about 0.08?µm were found (2.84?×?1012 precipitates cm?3) all across the host, whereas larger precipitates of about 0.17?µm were found (2.9?×?104 precipitates cm?1) along certain linear structural singularities of the matrix. These singularities, identified as crystal dislocations, were observed to terminate always either at a triple node of singularities or at the crystal surface, forming a three-dimensional network of crystal singularities (2.0?×?106 singularities cm?2), identified as the Frank network. The presence of europium exhaustive matrix zones accompanying the observed europium-decorated paths indicates that impurity segregation processes, occurring during annealing, favour the precipitation phenomena.  相似文献   

14.
A new type of multichannel olfactometer is described, and the results are given for gas chromatographical standardization of this equipment. The olfactometer keeps 24 odorous substances available for presentation, consecutively, two per trial, or combinations of the two. It produces concentrations of odorous gas in the air between 1 × l0?5 and 1 × 10?11 molecules/liter. The principle of construction is gradual dilution of an odorous gas in streaming purified air. The design provides for electronic control of stimulus sequence and response registration via punched tapes.  相似文献   

15.
Three experiments investigated the role of length, density, and number dimensions in children's numerosity judgments of linear arrays of beads. The number dimension is physically defined by a length × density rule. Judgments based, even in part, on the number dimension would show signs of a length × density rule. Experiment 1 examined numerosity judgments of large arrays. Results showed that judgments by 3- and 4-year-olds obeyed a length + density rule, providing cogent evidence for a general adding strategy in young children's judgments of quantity. The physical length × density rule emerged gradually with increasing age. Experiment 2 showed that numerosity judgments of small arrays by 3- and 4-year-olds obeyed a length × density rule, indicating response to the number dimension. This result was expected and thereby validated the linearity of the response scale at the youngest ages. Experiment 3 verified the integration rules for individual 3- and 4-year-olds. The integration rules were interpreted in terms of Piaget's stages of the development of quantification. No evidence for Piaget's initial stage was found. This leads to a new view of early quantification which grants young children the ability to integrate stimulus dimensions.  相似文献   

16.
The surface tensions of liquid ternary Ni–5%Cu–5%Fe, quaternary Ni–5%Cu–5%Fe–5%Sn and quinary Ni–5%Cu–5%Fe–5%Sn–5%Ge alloys were determined as a function of temperature by the electromagnetic levitation oscillating drop method. The maximum undercoolings obtained in the experiments are 272 (0.15T L), 349 (0.21T L) and 363?K (0.22T L), respectively. For all the three alloys, the surface tension decreases linearly with the rise of temperature. The surface tension values are 1.799, 1.546 and 1.357?N/m at their liquidus temperatures of 1719, 1644 and 1641?K. Their temperature coefficients are ?4.972?×?10–4, ?5.057?×?10?4 and ?5.385?×?10?4?N/m/K. It is revealed that Sn and Ge are much more efficient than Cu and Fe in reducing the surface tension of Ni-based alloys. The addition of Sn can significantly enlarge the maximum undercooling at the same experimental condition. The viscosity of the three undercooled liquid alloys was also derived from the surface tension data.  相似文献   

17.
Secondary defects induced by ion and electron irradiation up to 6?dpa (displacements per atom) at liquid-nitrogen temperature in GaSb thin films are compared. For Sn ion (60?keV) irradiation, voids were observed. However, for high-energy electron (2?MeV) irradiation, interstitial-type dislocation loops were produced. The densities of voids and interstitial-type dislocation loops were almost equivalent (8?×?1014?voids/m2 and 3?×?1014?loops/m2) after irradiations at the same damage level of 6?dpa. It is concluded that the formation of voids by ion irradiation follows the creation of localised vacancy defects in cascade damage.  相似文献   

18.
The pressure dependence of the electrical resistivity of three different samples of cassiterite, namely natural cassiterite SnO2, synthetic nanocrystalline SnO2 (with crystallite size 46?nm) and nanocrystalline Co-doped SnO2 (with crystallite size 32?nm), has been measured up to 7?GPa at room temperature. The resistivity of natural cassiterite SnO2 decreases from 2.5?×?104?Ωm at normal pressure and temperature to 1.7?×?104?Ωm at 7.0?GPa. The nanocrystalline SnO2 has a high resistivity 6.0?×?105?Ωm at normal pressure and temperature and decreases with pressure reaching a value of 2.98?×?105?Ωm at 7?GPa. The activation energy of the electrical conduction of the studied samples were found to be 0.32?eV for the natural SnO2, 0.40?eV for the nanocrystalline SnO2 sample and 0.28?eV for the nanocrystalline Co-doped SnO2. Measurements of the pressure dependence of the electrical resistivity of the Co-doped SnO2 showed a decrease from 3.60?×?105 to 5.4?×?104?Ωm at 7.0?GPa. We did not observe any pressure-induced phase transition in SnO2 up to 7?GPa. This study of the high-pressure phase stability of cassiterite corroborates the experimental findings of SnO2 nanoinclusions in diamonds.  相似文献   

19.
Electrical stimulation of the region of the lateral hypothalamus produced a consistent form of quiet-biting attack behavior in cats. In one series of experiments, cats, implanted with electrodes from which attack had been elicited, were anesthetized and then were injected with a bolus of 14C-2-deoxyglucose at the same time as electrical stimulation was delivered through the attack electrodes. Brains prepared for X-ray autoradiography revealed that lateral hypothalamic stimulation activated the classical medial forebrain bundle pathway supplying the septal region, diagonal band, lateral preoptic area, and ventral tegmental region. Stimulation of quiet-attack sites in perifornical hypothalamus resulted in the activation of a much more extensive projection system which included the central and lateral tegmental fields of the midbrain and pons, and central gray region, as well as the structures described above. In a second series of experiments, 3H-leucine was placed into the region of the electrode tip from which attack was elicited in order to identify more precisely the pathways arising from that site. In general, tritiated amino acid radioautography replicated the 14C-2-deoxyglucose findings. In addition, the amino acid radioautographic data revealed the presence of extensive projections from perifornical hypothalamus to such pontine structures as the nucleus locus coeruleus, motor nucleus of NV , and the lateral pontine tegmental field. The functional connections between the lateral hypothalamic “attack region” and lateral preoptic zone were also confirmed by electrophysiological methods.  相似文献   

20.
The Candecomp/Parafac (CP) method decomposes a three-way array into a prespecified number R of rank-1 arrays, by minimizing the sum of squares of the residual array. The practical use of CP is sometimes complicated by the occurrence of so-called degenerate sequences of solutions, in which several rank-1 arrays become highly correlated in all three modes and some elements of the rank-1 arrays become arbitrarily large. We consider the real-valued CP decomposition of all known three-sliced arrays, i.e., of size p×q×3, with a two-valued typical rank. These are the 5×3×3 and 8×4×3 arrays, and the 3×3×4 and 3×3×5 arrays with symmetric 3×3 slices. In the latter two cases, CP is equivalent to the Indscal model. For a typical rank of {m,m+1}, we consider the CP decomposition with R=m of an array of rank m+1. We show that (in most cases) the CP objective function does not have a minimum but an infimum. Moreover, any sequence of feasible CP solutions in which the objective value approaches the infimum will become degenerate. We use the tools developed in Stegeman (2006), who considers p×p×2 arrays, and present a framework of analysis which is of use to the future study of CP degeneracy related to a two-valued typical rank. Moreover, our examples show that CP uniqueness is not necessary for degenerate solutions to occur. The author is supported by the Dutch Organisation for Scientific Research (NWO), VENI grant 451-04-102.  相似文献   

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