A distributed memory model for serial-order information.

Presents a theory for the storage and retrieval of item and serial-order information in which items or events are represented as random vectors. Convolution is used as the storage operation, and correlation is used as the retrieval operation. A distributed memory system is assumed; all information is stored in a common memory vector. In principle, the theory can apply to item recognition, order recognition, probe and ordered recall, judgments of recency and frequency, lexical decision, and storage of higher-order units such as chunks or propositions. It applies to both accuracy and latency. Performance is predicted from the moments (expectation and variance) of the similarity distributions, and these can be derived from the theory. A canonical version of discrete memory models is outlined as a basis for comparison; it does not fit some serial-order recognition data as well as the distributed memory model does. (78 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Why we live and why we die

Several different techniques for urodynamic signal compression have been proposed in the last few years. Using these techniques it is possible to reduce the requirements for digital storage or transmission. There are a number of applications where it is essential to use such techniques in diagnostic and ambulatory urodynamics. The purpose of this study is to compare different techniques of urodynamic data compression. The so-called FAN, voltage triggered, two point projection and second difference methods. The comparison between the methods is based on 65 pressure, 46 uroflow and 18 surface electromyogram signals. The reduction ratio achieved for different allowable errors between the original and compressed signals is calculated and compared for the different techniques. Results show that it is possible to store urodynamic signals accurately at a low sampling rate, where FAN and voltage triggered methods seem to be superior to the rest.     

钢铁企业MES系统中的数据存储技术及其应用

对目前主要的数据存储技术进行了论述和分析,详细讨论了数据的存储及容灾管理问题,包括建立SAN存储体系,实现数据的集中存储、数据的备份管理、以及数据远程容灾等内容.构建了一个具有良好扩展性、可用性、可靠性,能提高网络整体性能的钢铁企业MES系统数据存储、备份及容灾解决方案.     

Memory skill.

Argues that acquired memory skills best account for individual differences in memory performance. W. G. Chase and K. A. Ericsson's (1982) theory that improved memory or memory skills are due to the acquisition of more efficient storage and retrieval processes using long-term memory (LTM) is presented. This theory specifies 3 principles that characterize the structure of memory skills: (1) Information rapidly stored in LTM is encoded in terms of knowledge structures in semantic memory (meaningful encoding); (2) during storage in LTM, special retrieval cues are explicitly associated with the memory encoding of the presented information (retrieval structure); and (3) encoding and retrieval operations using LTM can be dramatically sped up by practice, making the rate of information storage in LTM comparable to that of short-term memory. Empirical evidence of the exceptional performance of a large number of memory experts is examined in the light of these principles. It is contended that strong evidence for these principles has also been found for normal Ss, when they are given more than a couple of hours of practice or training on memory tasks. It is concluded that expert memory skill is related to normal Ss' superior memory for meaningful information. (French abstract) (4? p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A preliminary investigation into postmortem changes in skinfold impedance during the early postmortem period in rats

A highly accurate and reproducible technique was used to measure the electrical impedance (1 kHz) of a lateral abdominal skinfold, in each of eight rat cadavers stored at 9.0 +/- 0.7 degrees C, during the early postmortem period. Impedance increased exponentially between 1 and 120 h post mortem. Whether or not similar changes occur during the human postmortem period, and their potential value as a means of objective estimation of postmortem interval (PMI), remains to be established.     

Computerised transient hyperaemic response test--a method for the assessment of cerebral autoregulation

A simple bedside test has been developed to assess the state of autoregulation in subarachnoid haemorrhage patients. Transcranial Doppler was used to measure blood flow velocity in the middle cerebral artery after a brief common carotid compression. Acceleration of blood flow postcompression was interpreted as evidence of intact cerebral autoregulation. A program using the Windows environment was designed for signal analysis of the transient hyperaemic response test (THRT). The flow velocity signal from the TCD was recorded, carotid compression and release automatically detected and the test results immediately displayed and stored in a database. The program was verified in 614 tests; 552 of them were analysed off-line using previously recorded data and 62 on-line during the examination. A significant correlation was found between the results of computerised testing and the patient's neurological state.     

Effects of varying signal duration on pure-tone frequency discrimination in humans and monkeys

This study examined the effects of varying signal duration and pulse repetition rate on pure tone frequency difference limens (FDLs) at 500 Hz and 4 kHz in humans and monkeys. Two experiments examined FDLs as a function of tone duration from 12-400 ms, using stimuli presented either with a constant pulse rate, or with a constant interstimulus interval. In both cases, at 500 Hz, human FDLs increased more than monkey FDLs as duration decreased from 400 to 12 ms. This effect resulted in monkey FDLs that were about 14 times larger than human FDLs at 400 ms, but only about 4 times larger at 12 ms. At 4 kHz, human and monkey FDLs showed more similar rates of increase as duration decreased. A third experiment examined FDLs at 500 Hz for a 100-ms tone as a function of pulse rate (1 per 250-2000 ms). Here, FDLs for humans and monkeys varied in a similar fashion, indicating that both species' sensitivity was similarly affected by manipulating temporal variables relating to memory load, rather than sensory coding. These data provide evidence that, at 500 Hz, humans have a qualitatively different pure tone frequency analyzing mechanism from monkeys, possibly based on better access to phase-locking mechanisms.     

Analysis of the Doppler signal (color and pulsed) in hepatocarcinoma

Real time echocardiography associated with pulsed Doppler (duplex) and color (triplex) provide a non invasive technique to determine the vascular morphology of a lesion. The duplex and triplex signal of 35 liver tumors, 23 hepatocarcinomas and 12 angiomas found in the first high frequency signals greater than 1.81 kHz and traced with pulsatile or mixed morphology (pulsed and continuous) were analyzed. The second signals were of low frequency, less than 1 kHz and continuous tracing. It may be concluded than echo-Doppler is a complementary technique to conventional echography and is useful in the diagnosis of hepatocellular carcinoma.     

Selective adjustment of the speed of internal clock and memory processes.

Four experiments studied the scaling of time by male Charles River albino rats to determine if internal clock and memory processes could be selectively adjusted by pharmacological manipulations. Experiments used a temporal discrimination procedure in which 1 response ("short") was reinforced following a 2-sec noise signal and a different response ("long") was reinforced following an 8-sec noise signal; unreinforced signals of intermediate duration were also presented. The proportion of long responses increased as a function of signal duration. All drugs were administered ip. In Exp I, methamphetamine selectively increased and haloperidol selectively decreased clock speed. In Exp II, footshock stress increased clock speed during continuous administration but decreased clock speed below control values when the footshock was abruptly terminated. Exp III demonstrated that vasopressin and oxytocin selectively decreased the remembered durations of reinforced times, which suggests that memory storage speed increased. In Exp IV, physostigmine decreased, and atropine increased, these remembered durations, which suggests that memory storage speed was differentially affected. It is concluded that internal clock and memory processes can be dissociated by selectively adjusting their speed of operation and that these changes can be quantitatively modeled by a scalar timing theory. (61 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Transient evoked otoacoustic emissions in patients with normal hearing and in patients with hearing loss

OBJECTIVES: 1) To evaluate transient evoked otoacoustic emission (TEOAE) test performance when measurements are made under routine clinical conditions. 2) To evaluate TEOAE test performance as a function of frequency and as a function of the magnitude of hearing loss. 3) To compare test performance using univariate and multivariate approaches to data analyses. 4) To provide a means of interpreting clinical TEOAE measurements. DESIGN: TEOAEs were measured in 452 ears of 246 patients. All measurements were made after acoustic immittance assessments, which were used to demonstrate that middle-ear function was normal at the time of the TEOAE test. TEOAE amplitudes and signal to noise ratios (SNRs), analyzed into octave bands centered at 1, 2, and 4 kHz, were compared with the pure-tone threshold at the same frequencies. Data were analyzed with clinical decision theory, cumulative distributions, discriminant analyses, and logistic regressions. RESULTS: Using univariate analysis techniques, TEOAEs accurately identified auditory status at 2 and 4 kHz but were less accurate at 1 kHz. Test performance was best when audiometric thresholds between 20 and 30 dB HL were used as the criteria for normal hearing. TEOAE SNR resulted in better test performance than did TEOAE amplitude alone; this effect decreased as frequency increased. Multivariate analysis methods resulted in better separation between normal and impaired ears than did univariate approaches, which relied on only TEOAE amplitude or SNR when test frequency band and audiometric frequency were the same. This improvement in test performance was greatest at 1 kHz, decreased as frequency increased, and was negligible at 4 kHz. CONCLUSIONS: TEOAEs can be used to identify hearing loss in children under routine clinical conditions. Univariate tests accurately identified auditory status at mid and high frequencies but performed more poorly at lower frequencies. The decrease in performance as frequency decreases may be a result of increased noise at lower frequencies but also may be due to properties of the measurement paradigm ("QuickScreen," high-pass filter at 0.8 kHz), which would not be ideal for recording energy around 1 kHz. The improvement in test performance when SNR was used and the interaction of this effect with frequency, however, would be consistent with the view that test performance in lower frequencies is at least partially influenced by the level of background noise. Multivariate analysis techniques improved test performance compared with the more traditional univariate approaches to data analysis. An approach is provided that allows one to assign measured TEOAE amplitudes, SNRs, or outputs from multivariate analyses to one of three categories: response properties consistent with normal hearing; results consistent with hearing loss; hearing status undetermined.     

Repeated recall: A new model and tests of its generality from childhood to old age.

Describes a theory of human memory and formalizes it as a Markov model, tailored to predict sequences of recalls and forgets over successive attempts to remember a set of items. The memory processes governing the recall of an item are formalized as a probability of initial storage and as 4 memory functions, each providing a formal account of a certain process: a discrepancy function, an accumulation function, a relativity function, and a 1st-recall function. Exp I, using 33 undergraduates, found that a model that estimates the storage parameter and the 4 memory functions gave a good account of data, using 8 free parameters. In Exp II, the model was cross-validated and was fitted to data from 3 groups of Ss: 30 5th and 6th graders, 30 undergraduates, and 30 adults aged 53–73 yrs. The model fitted all ages equally well. The storage parameter varied with age; the parameters of the 4 memory functions did not. Discussion centers on competing models of memory and on the locus of age changes in memory. (49 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Discrete resource allocation in visual working memory.

Are resources in visual working memory allocated in a continuous or a discrete fashion? On one hand, flexible resource models suggest that capacity is determined by a central resource pool that can be flexibly divided such that items of greater complexity receive a larger share of resources. On the other hand, if capacity in working memory is defined in terms of discrete storage “slots,” then observers may be able to determine which items are assigned to a slot but not how resources are divided between stored items. To test these predictions, the authors manipulated the relative complexity of the items to be stored while holding the number items constant. Although mnemonic resolution declined when set size increased (Experiment 1), resolution for a given item was unaffected by large variations in the complexity of the other items to be stored when set size was held constant (Experiments 2–4). Thus, resources in visual working memory are distributed in a discrete slot-based fashion, even when interitem variations in complexity motivate an asymmetrical division of resources across items. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

How marsh tits find their hoards: The roles of site preference and spatial memory.

Marsh tits (Parus palustris) store single food items in scattered locations and recover them hours or days later. Some properties of the spatial memory involved were analyzed in 2 studies with 4 wild-caught marsh tits. In Exp I, Ss were offered 97 sites for storing 12 seeds. They recovered a median of 65% of them 2–3 hrs later, making only 2 errors/seed while doing so. Over trials, they used some sites more often than others, but during recovery they were more likely to visit a site of any preference value if they had stored a seed there that day than if they had not. Recovery performance was much worse if the experimenters moved the seeds between storage and recovery. A fixed search strategy that had some of the same average properties as the Ss' search behavior also did worse than the real birds. In Exp II, any tendency to visit the same sites on successive daily tests in the aviary was placed in opposition to memory for storage sites by allowing Ss to store more seeds 2 hrs after storing a 1st batch. They tended to avoid individual storage sites holding seeds from the 1st batch. When Ss searched for all the seeds 2 hrs later, they tended to recover more seeds from the 2nd than from the 1st batch, demonstrating a recency effect. (30 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Synthetic 2-amino alcohol derivatives as chiral auxiliaries

This work describes both the concepts used in an Object Manager for storage of medical images as one more data type associated to objects, and a support system developed to offer this kind of tool to medical application developers. The purpose of this work is to support the retrieval of images through queries based on the graphical contents of the stored images. The usual approach uses icons and textual attributes stored with the images to specify the queries. This work uses a novel modeling technique to define the "image data type," by means of which it is possible to decide, before the query itself, the key data of each image that must be extracted from the image when it is stored in the database, so the search can be accelerated when queries are issued. This approach enables building of expansible systems, where new image processing algorithms can be added easily, using its syntactic representation stored through an Image Meta-schema into the application database schema. This work shows how such a system has been implemented, and also provides a query language used to refer and execute these algorithms from inside the database management system.     

Distortion product otoacoustic emissions for the assessment of auditory sensitivity

Distortion product otoacoustic emissions (DPOAEs) were evaluated in 494 normal and 506 cochlear-impaired human ears, to determine whether DPOAEs depend on factors such as background noise, the shape of the pure tone audiogram, sex and aging, and whether a DPOAE test can perform well in distinguishing normal-hearing from hearing-impaired ears. The amplitudes of DPOAEs were measured at the frequency of 2f1-f2 (f1 < f2, f2/f1 = 1.22, f2 at 1, 2 and 4 kHz) using as stimuli two pure tones at level of 70 dB from an ILO92 Otoacoustic Emission Analyzer. The correlation coefficients between the DPOAE level and the auditory threshold decreased as the background noise levels at 1 kHz and 2 kHz increased. Therefore, it appeared that ears with large background noise levels would be inadequate for the study of DPOAEs predicting the hearing state. The sensitivity (normal-hearing ears identified as normal hearing) and the specificity (hearing-impaired ears identified as hearing impaired) at the equal-sensitivity-specificity condition were 80.7-86.7% at 1, 2 and 4 kHz, and the areas under the receiver operating characteristic (ROC) curves, which were used to estimate the test performance, were 0.88 for 1 kHz, 0.91 for 2 kHz and 0.92 for 4 kHz. Since these results suggest that a DPOAE can be used as a reliable technique for objective auditory tests, it is thought that actual values (DPOAE level: 4.3 dB at 1 kHz, 5.0 dB at 2 kHz and 2.9 dB at 4 kHz) of false-positive (hearing-impaired ears identified as normal hearing) rates corresponding to 5% can be used in clinical evaluation to separate normal hearing from hearing-impaired ears. There was, however, a significant age effect at 4 kHz on DPOAEs in the ears with the same pure tone hearing thresholds, and the areas of the ROC curves in subjects ranging from 10 to 29 years old were larger than in subjects over 50 years (1 kHz: 0.88 to 0.94 versus 0.83 to 0.84, 2 kHz: 0.95 versus 0.89, 4 kHz: 0.95 to 0.96 versus 0.88 to 0.89). Therefore, it is thought that age-adjusted norms may be necessary for the accurate interpretation of DPOAE results.     

攀钢MES应用服务器TMesAppPlatform的设计研发

介绍了为攀钢MES建设所设计研发的MES应用服务器平台软件TMesAppPlatform,简述了软件的设计思路和基本架构,重点阐述了系统研发所采用的关键技术及实现,可供类似平台软件的研发参考。     

Consequences of the 1979 Three Mile Island accident continued: further comment

The development of multimedia image review stations offers the cardiologist the ability to review multiple image sets in a single setting rather than moving from one review station to another. To accomplish this goal there are three essential barriers: 1) memory requirements for digital images; 2) standardization of data format; and 3) practical user interfaces. Image compression algorithms can be used to overcome the digital barrier; however, these must be used cautiously so as to not adversely affect image quality. The lack of standardization is being addressed by the implementation of the Digital Communication in Medicine (DICOM) standard, and practical user interfaces are being developed every day with the widespread implementation of World Wide Web technology. These solutions will allow the clinician to review all of a patient's image data in one location, such as in the office, on the nursing unit, or at home.     

The "One-Shot" Hypothesis for Context Storage.

In 3 experiments motivated by the implicit memory literature, the authors investigated the effects of different strengthening operations on the list strength effect (LSE) for explicit free recall, an effect posited by R. M. Shiffrin, R. Ratcliff, and S. E. Clark (1990) to be due to context cuing. According to the one-shot hypothesis, a fixed amount of context is stored when an item is studied for at least 1 or 2 s. Beyond the initial context storage, increases in study time or different orienting tasks do not influence the amount of context that is stored, and thus only spaced repetitions should produce a positive LSE. Consistent with prior findings, spaced repetitions always produced a positive LSE, but increases in depth of processing, study time, and massed repetitions did not. A model implements the one-shot hypothesis, and a role for context storage as a link between episodic and semantic memory is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A theory for the storage and retrieval of item and associative information.

Describes a theory in which items or events are represented as random vectors. Convolution is used as the storage operation, and correlation is used as the retrieval operation. A distributed-memory system is assumed; all information is stored in a common memory vector. The theory applies to both recognition and recall and covers both accuracy and latency. Noise in the decision stage necessitates a 2-criterion decision system, and over time the criteria converge until a decision is reached. Performance is predicted from the moments (expectation and variance) of the similarity distributions, and these can be derived from the theory. Several alternative models with varying degrees of distributed memory are considered, and expressions for signal-to-noise ratio and relative efficiency are derived. (40 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of storage conditions on cortisol, total thyroxine, and free thyroxine concentrations in serum and plasma of dogs

OBJECTIVE: To determine for dogs stability of cortisol, thyroxine (T4), and free thyroxine (fT4) in plasma and serum stored in glass or plastic tubes at -20, 4, 25, and 37 C. DESIGN: Prospective study. ANIMALS: Phase I, 7 Greyhounds; Phase II, 6 mixed-breed dogs. PROCEDURE: Phase I: blood was obtained after administration of thyroid-stimulating hormone and adrenocorticotropin. Serum and plasma samples from each dog were divided into 8 aliquots, 4 in glass and 4 in plastic tubes. A pair of aliquots, 1 in plastic and 1 in glass, were stored at -20, 4, 25, or 37 C for 5 days and then assayed for hormones. Phase II: blood was obtained without prior stimulation. For fT4 determination, serum from each dog was placed in plastic or glass tubes, assayed immediately, stored at -20 C for 5 days, and reassayed. Aliquots from each dog were also stored for 1 day at 4 or 25 C and then assayed. Samples for cortisol determination were handled as in phase I. RESULTS: Phase I: there was no effect of tube type (glass vs plastic) on cortisol. Cortisol concentrations decreased after storage in serum at 4, 25, and 37 C, and in plasma at 37 C, compared with storage at -20 C. There was no effect of sample type (serum or plasma) on T4. Thyroxine concentrations increased after storage at 37 C in glass, compared with storage at -20 C. The fT4 concentrations were lower in serum than plasma after storage at -20 C. Concentrations of fT4 increased after storage at 37 C in glass, compared with storage at -20 C. Phase II: the fT4 concentrations did not change after storage in any condition. There was no effect of tube type on cortisol concentrations. Serum cortisol concentrations decreased after storage at 37 C, compared with storage at -20 C. CLINICAL IMPLICATIONS: For cortisol, cooling of plasma is not necessary, but serum should be shipped cold. For T4 and fT4, serum is sufficient; contained within plastic tubes, samples can be shipped without cooling if assayed within 5 days.