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Results for “list randomization”

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PubMed2004

Episodic memory change in late adulthood: generalizability across samples and performance indices.

Younger adults recall more information from episodic memory tasks than do older adults. Because longitudinal studies are rare and often incompatible, the extent of actual late-life memory change is not well established. We assemble two different longitudinal samples of normal older adults, each of which is tested twice at a 3-year interval, using a large battery of episodic memory indicators. Together, two-wave data from both the Victoria Longitudinal Study in Canada (n = 400) and the Kungsholmen Project in Sweden (n = 168) cover a 40-year span of adulthood, ranging from 54 to 94 years of age. Principal memory tasks include categorizable word lists, story recall, and random word lists, as well as indicators of cognitive support. Overall, an examination of performance on sets of common and complementary episodic tasks reveals that, for both samples, actual 3-year changes are modest and that, when decline occurs, it is gradual. The exception-greater decline for more supported tasks-suggests that these may be especially sensitive to late-life changes.

Adult↗

PubMed1995

Multiple births and risk of breast cancer.

Data from a large, multicenter, population-based case-control study were analyzed to investigate the relation between multiple birth pregnancies and subsequent breast-cancer risk in the gravidas. Women less than 75 years old who had breast cancer were identified from statewide tumor registries in Wisconsin, western Massachusetts, Maine and New Hampshire. Controls aged less than 65 years were selected randomly from lists of licensed drivers, and controls aged between 65 and 74 were selected randomly from lists of Medicare beneficiaries. Information on reproductive history and other factors was obtained by means of telephone interviews. After excluding nulliparous women, 5,880 case subjects and 8,217 controls remained for analysis. Multiple birth pregnancies occurred in 146 cases and 218 controls. Adjusted for the number of full-term pregnancies and other confounders, the odds ratio (OR) for any multiple birth pregnancy was 0.94 (95% confidence interval, 0.75 to 1.17). The null association between multiple birth pregnancies and breast cancer remained if the mother's first pregnancy or last pregnancy resulted in a multiple birth. In addition, no trend in risk emerged for age at first multiple birth or time since last multiple birth. While other investigators have suggested biological mechanisms to explain both protective and detrimental effects of multiple births and subsequent development of breast cancer, this study does not support either assertion.

Adult↗

PubMed2006

Syntactic and semantic modulation of neural activity during auditory sentence comprehension.

In previous functional neuroimaging studies, left anterior temporal and temporal-parietal areas responded more strongly to sentences than to randomly ordered lists of words. The smaller response for word lists could be explained by either (1) less activation of syntactic processes due to the absence of syntactic structure in the random word lists or (2) less activation of semantic processes resulting from failure to combine the content words into a global meaning. To test these two explanations, we conducted a functional magnetic resonance imaging study in which word order and combinatorial word meaning were independently manipulated during auditory comprehension. Subjects heard six different stimuli: normal sentences, semantically incongruent sentences in which content words were randomly replaced with other content words, pseudoword sentences, and versions of these three sentence types in which word order was randomized to remove syntactic structure. Effects of syntactic structure (greater activation to sentences than to word lists) were observed in the left anterior superior temporal sulcus and left angular gyrus. Semantic effects (greater activation to semantically congruent stimuli than either incongruent or pseudoword stimuli) were seen in widespread, bilateral temporal lobe areas and the angular gyrus. Of the two regions that responded to syntactic structure, the angular gyrus showed a greater response to semantic structure, suggesting that reduced activation for word lists in this area is related to a disruption in semantic processing. The anterior temporal lobe, on the other hand, was relatively insensitive to manipulations of semantic structure, suggesting that syntactic information plays a greater role in driving activation in this area.

Adult↗

PubMed2001

Dairy-cattle health in Gyeongnam, Korea.

An animal-health monitoring system in the Gyeongnam area was started in 1997 to develop statistically valid data for use in estimating disease frequencies in dairy cattle, and the associated costs. The objectives of this study were to: (1) describe what was done to implement and maintain the system in Gyeongnam; (2) present selected disease frequencies; (3) discuss the epidemiological consideration of what was done and implications for results obtained. Veterinary medical officers (VMOs), comprising professors and graduate students from Gyeongsang National University, faculty of Gyeongnam Livestock Promotion Institute and clinic veterinarians, served as data collectors. After training on current disease and management problems of dairy cattle, interview techniques, sampling methods and data-collection instruments, the VMOs participated in selection of the sample herds and data gathering. Forty (n=40) of 167 dairy herds were selected randomly using a computer-generated list of random numbers and the VMOs visited farms once in a month for 12 months to collect data about management, disease, inventory, production, preventive treatment, financial and other relevant data. Strict data-quality control devices were used. Specific feed-back was developed for the producers and data collectors. The six disorders found most frequently in cows (from the highest to the lowest) were breeding problems, clinical mastitis, birth problems, gastrointestinal problems, metabolic problems and lameness. In young stock, respiratory, multiple system, breeding and gastrointestinal problems were predominant, whereas in calves, gastrointestinal, respiratory and integumental problems predominated.

Animal Husbandry↗

PubMed1970

Forgetting: trace erosion or retrieval failure?

A series of lists of random words was presented. Following each list, the subject attempted to recall the words of the list prior to the list just presented. Recall probability for a given word depended on the length of the list in which it was embedded, not on the length of the list intervening between presentation and test. These results indicate that forgetting is a failure in the memory search during retrieval rather than a degradation of the memory trace occurring between presentation and test.

Humans↗

PubMed2006

How much evolutionary history in a 10 x 10 m plot?

We use a fully dated phylogenetic tree of the angiosperm families to calculate phylogenetic diversity (PD) in four South African vegetation types with distinct evolutionary histories. Since the branch length values are in this case represented by the ages of plant lineages, PD becomes the cumulative evolutionary age (CEA) of assemblages. Unsurprisingly, total CEA increases with family and with species diversity and observed values are the same as expected from random sampling of family lists. However, when random sampling is done from species lists, observed CEAs are generally lower than expected. In vegetation types which have undergone recent diversification-grassland, fynbos and Nama-karoo-co-occurring species are more closely related than expected, but in subtropical thicket the observed CEAs are well described by random sampling. The use of CEA has great potential for assessing the age of biotic assemblages, particularly as the dating of genus and species-level phylogenies become more accurate.

Evolution, Molecular↗

PubMed1998

Homosexual parents: a comparative forensic study of character and harms to children.

40 appeals cases of custody disputes drawn systematically from all cases involving a homosexual parent in the United States were compared to 38 appeals cases involving heterosexual custody disputes drawn randomly from listings under parental "character" and 18 appeals cases drawn randomly from "general" cases in Dicennial Digest from 1966 to 1991. Each case involving homosexual vs heterosexual claimants was examined for recorded information about (1) the character of the homosexual parent, the associates of the homosexual parent, the heterosexual parent, and the associates of the heterosexual parent, (2) the effects, particularly harms, upon the child(ren), and (3) psychiatric opinion. 82% of the homosexual vs 18% of the heterosexual parents and 54% of the homosexual's associates vs 19% of the heterosexuals' associates were recorded as having poor character in cases involving a homosexual claimant. Of the 66 recorded harms, e.g., molestation, physical abuse, to the 73 children, homosexual persons accounted for 64 (97%). Of the 32 lesbians, 6 were recorded as having engaged in criminal activity and 3 of bringing false charges of child sexual abuse against the father. Psychiatric opinion, however, ran 25 to 12 in favor of custody for the homosexual parent. In the 56 heterosexual vs heterosexual comparison cases, 38% of the heterosexual parents and 28% of their associates were recorded as having poor character. Six harms to their 105 children and 3 instances of criminality but no false charges of sexual abuse were recorded. In the appeals court literature, homosexual parents were disproportionately of poor character and disproportionately associated with various harms to their children.

Adolescent↗

PubMed1993

Effects of structure and clustering on recall and recognition memory in clinical depression.

The present study compared retrieval of high, medium, and low structured material, using word lists consisting of uncategorized words and categorized words presented in randomized and clustered order. Clinically depressed subjects were found to be significantly impaired relative to controls only on the medium level of structure and the randomized categories list when measured by free recall. There were no effects of group nor any interactions for recognition memory, although there was a main effect for group on d' when signal detection analysis was applied. The implications of the findings for models of memory deficits in depression are discussed.

Adult↗

PubMed2004

Can semantic relatedness explain the enhancement of memory for emotional words?

Memory for emotional items is often better than memory for neutral items. In three experiments, we examined whether this typical finding is due to the higher semantic relatedness inherent to emotional items, a confound in previous studies. We also controlled for other possible confounding variables, such as imagery. In Experiments 1 and 2, participants encoded lists of emotional and categorized neutral words equivalent in semantic relatedness, as well as lists of random neutral words with lower semantic relatedness. In Experiment 3, the lists were mixed, containing words from all the conditions. Surprise free recall was tested after a 40- to 55-min retention interval. Free recall of emotional words was better than that of random neutral words, replicating the classic effect. Importantly, categorized words were recalled better than random neutral words, and not worse than emotional words. These results emphasize the important role of semantic relatedness in the classic effect and suggest that organizational processes operate alongside arousal-related ones to enhance memory for emotional material.

Adult↗

PubMed2006

A randomized controlled trial of interim methadone maintenance: 10-Month follow-up.

This study compares interim maintenance (IM) to a waiting list condition at an opioid treatment program (OTP). As defined by US federal regulations, IM provides observed methadone dosing and emergency counseling only for a maximum of 120 days. Three hundred and nineteen individuals enrolled on an OTP waiting list were randomly assigned on a 3:2 basis to either IM or waiting list control. Outcomes were measured at OTP entry (or at 4 months from baseline for those who did not enter treatment), and 6 months thereafter. At the second follow-up, 129 (64.8%) of the IM participants reported being enrolled in an OTP, versus 33 (27.5%) of the controls, p<.001. Significant treatment conditionxtime interaction effects occurred for heroin and cocaine use (both p's<.001) and the ASI Legal composite score (p<.001). Moreover, a significant difference occurred between conditions at the second follow-up for heroin-positive drug tests (interim 48.1% versus control 72.3%, p=.001) but not for cocaine-positive drug tests. At 10 months after study enrollment, there are sustained benefits of IM as compared to waiting list in terms of increased treatment entry and reduced heroin use and criminal behavior.

Adult↗

PubMed2000

Comparison of the standard and the computerized versions of the Symptom Check List (SCL-90-R): a randomized trial.

OBJECTIVE: The purpose of this study was to examine whether computer administration of the Symptom Check List (SCL-90-R) is equivalent to paper-and-pencil originals. METHOD: 282 psychosomatic outpatients were randomly assigned to computer or paper-and-pencil conditions. Statistical equivalence tests were used to examine psychometric equivalence for the means. Reliabilities and correlations were compared for the two methods of administration. RESULTS: No systematic differences were observed in group means for most of the subscales. Subjects of the computer-administered group scored higher on the SCL-90-R subscale 'Obsessive-Compulsive' and 'Anger-Hostility' than the control subjects. Gender and administration mode interaction was observed for one subscale, while age and administration interaction was observed for another subscale. CONCLUSION: Using computer-administered tests makes administration and scoring of tests more efficient. The differences between the two administration modes were small, although noticeable. Further research is needed to determine whether computer environment, computer experience and age may influence the test results.

Adult↗

PubMed1980

A clinician-judged technique for quantifying dysarthric speech based on single-word intelligibility.

A clinician-judged technique for quantifying dysarthric speech based on single-word intelligibility was developed and evaluated in three experiments. Dysarthric speakers were audio-recorded as they read 50-word lists that had been randomly generated from sets of similar sounding words. These tapes were judged by speech pathologists using listening formats that were systematically altered by varying the number of choices available to the judges. Results indicated that some formats were more sensitive to differences that exist among severely dysarthric speakers and others were more sensitive to differences that exist among mild to moderately dysarthric speakers. Judge familiarity with the master word pool increased scores slightly but in a consistent and predictable fashion. Scores from different randomly generated word lists were similar when the influence of a speaker's day-to-day variability was controlled. Clinical implications and uses of this technique for the monitoring of change in speaker performance were discussed.

Adolescent↗

PubMed2000

Random costs in combinatorial optimization

The random cost problem is the problem of indentifying the minimum in a list of random numbers. By definition, this problem cannot be solved faster than by exhaustive search. It is shown that a classical NP-hard optimization problem, number partitioning, is essentially equivalent to the random cost problem. On the one hand this explains the bad performance of heuristic approaches to the number partitioning problem, but on the other hand it allows one to calculate the probability distributions of the optimum and suboptimum costs.

Journal Article↗

PubMed1982

[Immunoglobulins in bacterial and viral meningitis. Results of a controlled randomized clinical study of intravenous and intrathecal application].

The efficacy of additional intravenous and intrathecal immunoglobulin (Ig) therapy was investigated in a randomized clinical trial with 68 patients divided with the aid of a list of random numbers into two groups according to their infection. The group of bacterial infections of the CNS included 29 patients and the group of virus infections of the CNS 39 patients. The statistical evaluation of patients with bacterial infections and of those with virus infections was done separately. Group 1 received 10 g Ig each as a short infusion on two consecutive days. Patients with bacterial infections received in addition on every second day and patients with viral infections on every fifth day 500 mg of the same preparation by intrathecal injection. In contrast to this, a control group received the usual therapy only, principally antibiotics for purulent meningitis. The following characteristics were investigated and compared as variable criteria of the course of the disease and consequently of the efficacy of the additional therapy with Ig: CSF cell count, CSF protein, pyrexia, general condition, paralyses, neuropsychological defects, vigilance and EEG recording. As overall criteria of the course of the disease the length of stay in hospital and the rise in temperature were considered. The results of the statistical analysis showed a statistically significant superiority for the Ig-treatment which was most marked in the regression of the CSF pleocytosis, total CSF protein and pyrexia. For the subjectively graded clinical evaluations such as general condition, disturbances of vigilance, transient paralyses, neuropsychological defects and EEG tracings the statistical significance still applied, even if not so pronounced as for the previously mentioned criteria.

Adult↗

PubMed2002

The effect of item sequence on brain activity during recognition memory.

Two basic types of experimental designs are available to measure the brain indices of successful recognition memory. Both designs have in common that brain activity elicited by correctly recognized studied (old) items is compared to brain activity elicited by correctly rejected new items. In blocked designs, the two item types are presented in separate lists. In random-mixed designs, on the other hand, they are randomly intermixed within the same list. Early studies reported that in random-mixed designs, brain activity can be affected by the sequence in which different types of items are presented. Here, we investigated to what extent such sequence effects also occur in random-mixed designs of recognition memory. Event-related potentials (ERPs) were obtained while subjects made recognition judgments on pseudorandom sequences of visually presented new and old words. Changes in the sequence from one item-type to another (change from old to new and from new to old) were associated with a prominent P300 potential for new words following old words but not vice versa. Subjects with larger P300 potentials made less false alarms to such new words. Successive presentations of the same item-type (sequence 'blocks': three old words in a row and three new words in row) were associated with a left parietal positive slow shift for successive old words but not for successive new words. The data suggest that new words require extensive context-updating if they are presented within the context generated by preceding old words. Due to these sequence effects, the present data question the assumption that random-mixed designs are generally favorable over block designs.

Adult↗

PubMed1991

Semantic organization and verbal episodic memory in patients with mild and moderate Alzheimer's disease.

The objective of the present research was to investigate the relationship between semantic organization and cue utilization in mildly and moderately demented patients with Alzheimer's disease (AD). In Experiment 1, subjects were presented with two lists of words: a list with semantically unrelated words and a list with words from four semantic categories presented randomly intermixed. Free recall was assessed and following the organizable list, subjects received a cued recall test. Normal controls, as opposed to mildly and moderately demented patients, showed higher performance in the organizable list as compared to the random list. In addition, normal controls and mildly demented patients benefited from semantic cues in the organizable list and performed at a higher level in total recall as compared to free recall. In Experiment 2, subjects were presented with two lists of words: a list with words from four semantic categories presented randomly intermixed and a list with words from four semantic categories presented clustered, together with information about the organization of the list. Free recall and cued recall, with the category names serving as cues, were assessed. Free recall performance of normal controls was higher in the clustered than in the organizable list, whereas no such effect was observed for the AD patients. Normal controls and mildly demented patients performed at a higher level in total as compared to free recall in both lists, whereas this effect was present only in the clustered list for the moderately demented patients. The overall pattern of results indicates that there are conditions under which memory facilitation from semantic organization may be obtained in AD.

Aged↗

PubMed2002

Use of a MeSH-based index of faculty research interests to identify faculty publications: an IAIMSian study of precision, recall, and data reusability.

OBJECTIVE: To determine whether MEDLINE searches based on an existing automated faculty research interest index or on author name entities can be used to automate construction of accurate online lists of faculty publications. METHODS: Curricula vitae (CVs) for 36 faculty members were selected at random. Their lists of journal publications were used to determine recall and precision of two MEDLINE search strategies. OUTCOME: Most faculty publications in the CVs (86%) were indexed in MEDLINE. The research-interest-enhanced MEDLINE searches retrieved citations in the CVs that were also in MEDLINE with a recall of 0.53 and precision of 0.85. For every 10 citations in the research interest-enhanced search, on average 8.5 were in the CVs. The name entity searches retrieved a higher proportion of citations in the CVs (recall 0.94, precision 0.59) with a higher rate of citations not in the CVs: For every 10 citations in the faculty name searches, 7.3 citations were in the CVs. Name commonness or clinical or basic sciences appointment did not change these results. CONCLUSION: MEDLINE searches, especially those based on research interests, can be used to populate faculty publication lists with high rates of accuracy. Author based searches can also be used, but they retrieve a higher proportion of irrelevant citations. This study confirms a successful instance of data reusability and integration at a large health academic sciences institution.

Abstracting and Indexing↗

PubMed1980

Knowledge acquisition in oncology from randomized therapeutic trials.

Appreciating the impact, on the progress of our knowledge, of randomized therapeutic trials performed over a period of thirty years leads to a two-fold approach: a) Drawing up the list of randomized trials and assessing the impact of their conclusions on the progress of our knowledge and on the improvement of standard therapy; b) from recognised progress in oncology, appraising the part played by randomized trials in the acquisition of that knowledge.

Clinical Trials as Topic↗