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21.
Four experiments contrasted the cue-familiarity hypothesis of feeling-of-knowing judgments (FKJs) and tip-of-the-tongue feelings (TOTs) to the target-retrievability hypothesis. Familiarity of the cues was contrasted to memorability of the targets in a paired-associate design (e.g., A-B A-B, A-B A-B', A-B A-D, A-B C-D), in which the number of repetitions of the cue A terms was dissociated from the memorability of the target B terms. Little support was found for the target-retrievability hypothesis, because in none of the 4 experiments were FKJs related to target memorability. In one experiment, an omnibus retrieval hypothesis (which implicates total retrieval rather than just correct retrieval) and the cue-familiarity hypothesis produced isomorphic predictions that were borne out by the FKJ and TOT results. All 4 experiments supported the cue-familiarity hypothesis, because FKJs and TOTs were directly related to the number of presentations (and thereby the familiarity) of the cues. 相似文献
22.
Randomized trial of breast self-examination in Shanghai: methodology and preliminary results 总被引:3,自引:0,他引:3
DB Thomas DL Gao SG Self CJ Allison Y Tao J Mahloch R Ray Q Qin R Presley P Porter 《Canadian Metallurgical Quarterly》1997,89(5):355-365
BACKGROUND: The efficacy of breast self-examination in helping to reduce mortality from breast cancer has not been rigorously demonstrated. PURPOSE: To assess efficacy, a large, randomized trial was initiated in Shanghai, China. METHODS: From October 1989 to October 1991, 267040 current and retired female employees associated with 520 factories in the Shanghai Textile Industry Bureau were randomly assigned on the basis of factory to either a self-examination instruction group (133375 women) or a control group (133665 women). The women were born within the period from 1925 through 1958. Women in the instruction group were given intensive training in breast self-examination, including the use of silicone breast models and personalized instruction, plus two subsequent reinforcement sessions and multiple reminders to practice the technique. Women in the control group were asked to attend training sessions on the prevention of low back pain. All women have been followed for the development of breast diseases and for death from breast cancer. RESULTS: A high level of participation during the first 4-5 years of the trial was documented among women in the instruction group. Randomly sampled women in this group demonstrated greater proficiency in detecting lumps in breast models than did randomly sampled women in the control group. Approximately equal numbers of breast cancers were detected in the two groups (331 in the instruction group and 322 in the control group) through 1994, which is the last year for which case-finding efforts have been completed. The breast cancers detected in the instruction group were not diagnosed at an appreciably earlier stage or smaller size than those in the control group. More benign breast lesions were detected in the instruction group than in the control group (1457 versus 623, respectively), suggesting a higher index of suspicion for women who received training. Cumulative breast cancer mortality rates through 5 years from entry into the study were nearly equivalent for the two groups. CONCLUSIONS: Breast self-examination has not led to a reduction in mortality from breast cancer in this study cohort in the first several years since the trial began. A shift toward the diagnosis of disease at a less advanced stage in women given instruction has also not been demonstrated. Longer follow-up of participants in this trial is required before final assessment can be made of the efficacy of breast self-examination. IMPLICATIONS: At this time, there is insufficient evidence to recommend for or against the teaching of breast self-examination. 相似文献
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The scalar transform is a new representation for signals, offering a perspective that is different from the Fourier transform. We introduce the notion of a scalar periodic function. These functions are then represented through the discrete scale series. We also define the notion of a strictly scale-limited signal. Analogous to the Shannon interpolation formula, we show that such signals can be exactly reconstructed from exponentially spaced samples of the signal in the time domain. As an interesting, practical application, we show how properties unique to the scale transform make it very useful in computing depth maps of a scene 相似文献
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2',4'-Dihydroxyacetophenone, also known as resoacetophenone, is a commercially important intermediate which is generally
prepared by the acylation of resorcinol with acetic acid in the presence of a molar excess of zinc chloride, which leads to
waste disposal problems. The most frequently used acylating agents such as acetic anhydride and acetyl chloride have several
disadvantages and need to be replaced by cheap and benign agents. In this connection, acetic acid is a better choice but with
a non-polluting and reusable catalyst. The synthesis of 2',4'-dihydroxyacetophenone from resorcinol and acetic acid was carried
out in the presence of a variety of solid acid catalysts such as montmorillonite clay (K-10), dodecatungstophosphoric acid
(DTP) supported on K-10, sulfated zirconia and ion exchange resins. Amongst these catalysts, Amberlyst-36, an ion exchange
resin, was found to be the most effective. The effects of various parameters on the rate of reaction and selectivity were
investigated to establish the intrinsic kinetics of the reaction. It was possible to deduce the adsorption equilibrium constant
and rate constant simultaneously for the reaction including the corresponding energies of activation. The catalyst is reusable.
The process is in consonance with the principles of green chemistry.
Electronic Publication 相似文献
27.
In this paper we report the impact of hot-carrier stress on analog performance of n- and p-MOSFET's with conventional oxide, NH3-nitrided oxide (RTN) and reoxidized nitrided oxide (RTN/RTO) as gate dielectrics. Changes due to hot-carrier stress in crucial analog parameters viz., drain output resistance, voltage gain, and input offset voltage of a source coupled differential MOSFET pair are investigated. Results show that RTN/RTO gate dielectrics suppress degradation of analog parameters in n-MOSFET's but increase it slightly in p-MOSFET's, as compared to conventional oxide MOSFET's 相似文献
28.
The exoglucanase/xylanase from Cellulomonas fimi (Cex) has been subjected to a detailed kinetic investigation with a range of aryl beta-D-glycoside substrates. This enzyme hydrolyzes its substrates with net retention of anomeric configuration, and thus it presumably follows a double-displacement mechanism. Values of kcat are found to be invariant with pH whereas kcat/Km is dependent upon two ionizations of pKa = 4.1 and 7.7. The substrate preference of the enzyme increases in the order glucosides < cellobiosides < xylobiosides, and kinetic studies with a range of aryl glucosides and cellobiosides have allowed construction of Broensted relationships for these substrate types. A strong dependence of both kcat (beta 1g = -1) and kcat/Km (beta 1g = -1) upon leaving group ability is observed for the glucosides, indicating that formation of the intermediate is rate-limiting. For the cellobiosides a biphasic, concave downward plot is seenj for kcat, indicating a change in rate-determining step across the series. Pre-steady-state kinetic experiments allowed construction of linear Broensted plots of log k2 and log (k2/Kd) for the cellobiosides of modest (beta 1g = -0.3) slope. These results are consistent with a double-displacement mechanism in which a glycosyl-enzyme intermediate is formed and hydrolyzed via oxocarbonium ion-like transition states. Secondary deuterium kinetic isotope effects and inactivation experiments provide further insight into transition-state structures and, in concert with beta 1g values, reveal that the presence of the distal sugar moiety in cellobiosides results in a less highly charged transition state.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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Of all the methods customarily used to transform E. coli we found only electroporation to be effective for transformation of the Gram-negative bacterium Vitreoscilla, yielding 5.10(5) transformants/microgram of plasmid DNA. The conditions used were close to those described for E. coli E. coli plasmids are stably maintained in Vitreoscilla. This is the first report of exogenous DNA transfer in Vitreoscilla which opens the way for the application of recombinant-DNA techniques to study this unique group of organisms. 相似文献