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81.
82.
Anderson Michael C.; Reinholz Julia; Kuhl Brice A.; Mayr Ulrich 《Canadian Metallurgical Quarterly》2011,26(2):397
People often encounter reminders to memories that they would prefer not to think about. When this happens, they often try to exclude the unwanted memory from awareness, a process that relies upon inhibitory control. We propose that the ability to regulate awareness of unwanted memories through inhibition declines with advancing age. In two experiments, we examined younger and older adults' ability to intentionally suppress retrieval when repeatedly confronted with reminders to an experience they were instructed to not think about. Older adults exhibited significantly less forgetting of the suppressed items compared to younger adults on a later independent probe test of recall, indicating that older adults failed to inhibit the to-be-avoided memories. These findings demonstrate that the ability to intentionally regulate conscious awareness of unwanted memories through inhibitory control declines with age, highlighting differences in memory control that may be of clinical relevance in the aftermath of unpleasant life events. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
83.
Temporal and spatial trends of atmospheric polychlorinated biphenyl concentrations near the Great Lakes 总被引:1,自引:0,他引:1
Polychlorinated biphenyl (PCB) concentrations were measured in the atmosphere at six regionally representative sites near the five Great Lakes from 1990 to 2003 as part of the Integrated Atmospheric Deposition Network (IADN). Concentration data for several individual PCB congeners and for total PCBs were analyzed for temporal and spatial trends after correcting for the temperature dependency of the partial pressures. Atmospheric PCB concentrations are decreasing relatively slowly for tetra- and pentachlorinated congeners, an observation that is in agreement with primary emissions modeling. Relatively rapid decreases in PCB concentrations at the sites near Lakes Michigan and Ontario may reflect successful reduction efforts in Chicago and Toronto, respectively. Atmospheric PCB concentrations near Lakes Superior and Huron are now so low that the air and water concentrations may be close to equilibrium. Atmospheric PCB concentrations at sites near Lakes Michigan, Erie, and Ontario are relatively higher than those measured at sites near Lakes Superior and Huron. The highest PCB level was observed at the site near Lake Erie, most likely due to nearby urban activity. However, this relatively higher concentration is still 6-10 times lower than that previously reported at the Chicago site. A correlation between average gas-phase PCB concentration with local population indicates a strong urban source of PCBs. The temperature dependence of gas-phase PCB concentrations is similar at most sites except at Burnt Island on Lake Huron, where very low concentrations, approaching virtual elimination, prevent reliable temperature correlation calculations. 相似文献
84.
85.
The study of the Na3PO4Na2SO4 system at 1050°C has proved the existence of the solid solution Na3?xP1?xSxO4 (0<x≤0.58) for which the cubic symmetry (Li3Bi-type structure) of the “high temperature” form γ-Na3PO4 is maintained. The room temperature variation of the parameter of the unit cell as a function of doping level and the homogeneity range are discussed. The replacement of PO3?4 ions by SO2?4 ions in Na3?xP1?xSxO4 leads to better ionic conductivity. The results are explained on the bases of structural and size considerations. A conduction mechanism is proposed. 相似文献
86.
JM Vallat P Sindou PM Preux F Tabaraud AM Milor P Couratier E LeGuern A Brice 《Canadian Metallurgical Quarterly》1996,39(6):813-817
The purpose of this study was to determine the accuracy of a video system which our laboratory has been using to measure soft tissue strain. Both static and dynamic error analyses were performed to assess the accuracy of our video system. Static error was defined as the amount of movement reported by the video system for markers that were stationary. Dynamic error was defined as the difference between the motion of the markers as reported by the video system and their actual motion. Two sets of fluorescent markers were attached to a servo-hydraulic materials test machine. One marker set was attached to the hydraulic actuator (moving markers) and the other set was attached to the base of the machine (stationary markers). Five different marker sizes, five camera distances, and seven different loading rates were studied. Results indicated that the static error was independent of marker size, and that the dynamic error was independent of the loading rate and marker size for loading rates of 50% of the camera field of view (CFV) per second or slower. For loading rates greater than 50 percent of CFV per second, the marker size did have an affect on the dynamic error. The mean static error was found to be 0.026 percent of CFV and the mean dynamic error was found to be 0.062 percent of CFV. 相似文献
87.
A Brice 《Canadian Metallurgical Quarterly》1998,46(9):710-712
Parkinson's disease (PD) is one of the most frequent neurodegenerative disorders. The role of genetic factors in its pathogenesis is supported by several lines of evidence: the high concordance in twins using PET scan; the increased risk among relatives of PD patients in case control and family studies; the existence of monogenic forms of PD. the alpha-synuclein gene is involved in a rare dominant form of the disease for which a new locus has been recently mapped to chromosome 2. Early onset autosomal recessive parkinsonism, which maps to chromosome 6q, appears to be frequent in Japan and in Europe. The genes for several monogenic forms of this entity should be identified soon, providing new insight into the pathophysiology of the disease. However, it is not clear if these genes will be relevant to apparently sporadic cases. In the long term, genotyping of affected sib-pairs should permit localisation and identification of other genetic susceptibility factors. These complementary approaches will contribute to the elucidation of the mechanism of PD and should provide new targets for drug therapies. 相似文献
88.
Brice Lecampion Andrei Constantinescu Laurent Malinsky 《Canadian Metallurgical Quarterly》2006,6(3):201-208
This paper discusses the identification of poroelastic constants and hydraulic conductivity from two transient laboratory tests performed on cylindrical core: drained isotropic confinement and pulse test. The combination of the two tests allows us to estimate all poroelastic parameters with the exception of the shear modulus. Despite the lack of analytical solutions for the fully coupled case, closed form solutions of the forward problems are obtained for a slender specimen. The validity of these solutions for a realistic aspect ratio of the core is assessed by a comparison with a finite element model. The identification problem is solved by minimizing a least square functional using an explicit gradient computed using the direct differentiation of the closed form solution and a Levenberg–Marquardt algorithm. The uniqueness of this inverse problem as well as the effect of noise on input data are fully discussed. The identification procedure is then applied to tests performed on a deep argillaceous rock (argillite of Meuse Haute–Marne). 相似文献
89.
Ivira B Benech P Fillit R Ndagijimana F Ancey P Parat G 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2008,55(2):421-430
This paper deals with the temperature dependence of electrical and physical features of various kinds of solidly mounted resonators (SMR). The presented bulk acoustic wave (BAW) devices are designed for the 2 GHz application. The temperature coefficient of frequency (TCF) is determined from measurements well above the temperature range defined for wireless telecommunication system specifications. Therefore, evolution of electromechanical coupling factors and quality factors at resonance and antiresonance are also monitored. Results of characterizations show the trend for a subsequent theoretical temperature compensation study by using analytical modeling. To improve accuracy of modeling, an attempt to extract temperature dependence of dielectric permittivity epsilon(33) and piezoelectric coefficient e(33) is made. Finally, a well-known analytical model is modified to take into account the temperature dependence of length, density, stiffness coefficient, dielectric permittivity, and piezoelectric coefficient. Modeling highlights the need to deposit a material with positive temperature coefficient of stiffness on the top electrode. Realistic thickness of such a layer is determined. At the same time, it is necessary to adjust piezoelectric and electrode thin film thicknesses for simultaneously keeping a constant antiresonance frequency, reaching a zero temperature coefficient of frequency for antiresonance, and minimizing the decrease in the coupling factor because of the mass-loading deposition. 相似文献
90.
Since the mid 1990s, Phytophthora ramorum has been responsible for the widespread mortality of tanoaks, as well as several oak species throughout California and Oregon
forests. However, not all trees die, even in areas with high disease pressure, suggesting that some trees may be resistant
to the pathogen. In this study, the chemical basis of host resistance was investigated. Three field experiments were carried
out in California between December 2004 and September 2005. The levels of nine phenolic compounds (gallic acid, catechin,
tyrosol, a tyrosol derivative, ellagic acid, and four ellagic acid derivatives) extracted from the phloem of trees that had
been either artificially inoculated with P. ramorum or trees putatively infected with P. ramorum (based on canker symptoms) were quantified by high-performance liquid chromatography (HPLC). Significant differences in phenolic
profiles were found between phloem sampled from the active margins of cankers, healthy phloem from asymptomatic trees, and
phloem sampled 60 cm away from canker sites, although the magnitude and direction of the responses was not consistent across
all experiments. Concentrations of gallic acid, tyrosol, and ellagic acid showed the greatest differences in these different
tissues, but varied considerably across treatments. Gallic acid and tyrosol were tested in in vitro bioassays and showed strong dose-dependent inhibitory effects against P. ramorum, P. cinnamomi, P. citricola, and P. citrophthora. These results suggest that phloem chemistry varies in response to pathogen infection in California coast live oak populations
and that changes in phloem chemistry may be related to apparently resistant phenotypes observed in the field.
Frances S. Ockels and Alieta Eyles contributed equally to the paper 相似文献