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PubMed1991

[Mitral regurgitation due to redundant chordae].

This paper reports the etiology and the findings of phonocardiograms and echocardiograms in four cases with mitral regurgitation caused by the redundant chordae. Redundancy of the chordae were determined by the surgeon during operation. The results were as follows: 1. The etiology of redundant chordae was either congenital, rheumatic, or mucoid degeneration. 2. Phonocardiographic findings of this condition are a holosystolic murmur accompanied by a diastolic rumble at the apex. 3. Two-dimensional echocardiogram shows holosystolic bulging of the mitral leaflet to which redundant chordae are attached. 4. The findings of the M-mode echocardiogram are multiple linear echoes and bowing of the mitral valve in systole.

Adult↗
PubMed1984

Why young listeners do not benefit from differentiating verbal redundancy.

Previous research has shown that young listeners, unlike older ones, do not benefit from verbal redundancy because of developmental differences in the decision criterion used when responding. Could some of the developmental differences in how listeners respond to redundant communications be due to their drawing age-related different conclusions about what the speaker meant to convey with the utterance? This study investigated whether young listeners make certain, perhaps unwarranted, assumptions about speaker authoritativeness. First and fourth graders heard stories in which a protagonist had to respond to what could be interpreted as redundant directions. They were asked to judge how the protagonist would respond. Stories varied in terms of both the age and the certainty of the speaker. Possible response options varied on how the protagonist utilized and hence responded to the "verbal redundancy." The results indicated that when there are no explicit markers indicating speaker certainty, young children make different inferences than older ones about speaker meaning. Thus, these data help to show the importance of determining how listeners in a communicative interaction judge and interpret what they hear.

Child↗
PubMedDate not supplied

[Redundancy of genetic sequences and mosaic structure of a genome].

A new method is developed to measure and compare the redundancy of genes. The method is based on the creating a Frequency/Correlation Dictionary of a gene. The Dictionary is a set of all possible words (i.e., subsequences) which could be met within a gene, of a length from 1 to N, where N is the length of the gene. The measure of redundancy of a gene is the minimal length of words which occur in the gene as a single copy. The results of the redundancy measurements are presented in the paper. It is shown that genes are not homogeneous in respect of redundancy of various sites in the gene. This phenomenon was called a mosaic pattern.

Genome, Human↗
PubMed1999

Intuitive theories of information: beliefs about the value of redundancy.

In many situations, quantity estimates from multiple experts or diagnostic instruments must be collected and combined. Normatively, and all else equal, one should value information sources that are nonredundant, in the sense that correlation in forecast errors should be minimized. Past research on the preference for redundancy has been inconclusive. While some studies have suggested that people correctly place higher value on uncorrelated inputs when collecting estimates, others have shown that people either ignore correlation or, in some cases, even prefer it. The present experiments show that the preference for redundancy depends on one's intuitive theory of information. The most common intuitive theory identified is the Error Tradeoff Model (ETM), which explicitly distinguishes between measurement error and bias. According to ETM, measurement error can only be averaged out by consulting the same source multiple times (normatively false), and bias can only be averaged out by consulting different sources (normatively true). As a result, ETM leads people to prefer redundant estimates when the ratio of measurement error to bias is relatively high. Other participants favored different theories. Some adopted the normative model, while others were reluctant to mathematically average estimates from different sources in any circumstance. In a post hoc analysis, science majors were more likely than others to subscribe to the normative model. While tentative, this result lends insight into how intuitive theories might develop and also has potential ramifications for how statistical concepts such as correlation might best be learned and internalized.

Adult↗
PubMed2000

Characterization of Hoxa-10/Hoxa-11 transheterozygotes reveals functional redundancy and regulatory interactions.

Hox genes show related sequences and overlapping expression domains that often reflect functional redundancy as well as a common evolutionary origin. To accurately define their functions, it has become necessary to compare phenotypes of mice with single and multiple Hox gene mutations. Here, we focus on two Abd-B-type genes, Hoxa-10 and Hoxa-11, which are coexpressed in developing vertebrae, limbs, and reproductive tracts. To assess possible functional redundancy between these two genes, Hoxa-10/Hoxa-11 transheterozygotes were produced by genetic intercrosses and analyzed. This compound mutation resulted in synergistic defects in transheterozygous limbs and reproductive tracts, but not in vertebrae. In the forelimb, distal radial/ulnar thickening and pisiform/triangular carpal fusion were observed in 35 and 21% of transheterozygotes, respectively, but were effectively absent in Hoxa-10 and Hoxa-11 +/- forelimbs. In the hindlimb, distal tibial/fibular thickening and loss of tibial/fibular fusion were observed in >80% of transheterozygotes but in no Hoxa-10 or Hoxa-11 +/- hindlimbs, and all transheterozygotes displayed reduced medial patellar sesamoids, compared to modest incidences in Hoxa-10 and Hoxa-11 +/- mutants. Furthermore, while the reproductive tracts of Hoxa-10 and Hoxa-11 single heterozygous mutants of both sexes were primarily unaffected, male transheterozygotes displayed cryptorchidism and abnormal tortuosity of the ductus deferens, and female transheterozygotes exhibited abnormal uterotubal junctions and narrowing of the uterus. In addition we observed that the targeted mutations of Hoxa-10 and Hoxa-11 each affected the expression of the other gene in the developing prevertebra and reproductive tracts. These results provide a measure of the functional redundancy of Hoxa-10 and Hoxa-11 and a deeper understanding of the phenotypes resulting in the single mutants and help elucidate the regulatory interactions between these two genes.

Animals↗
PubMed1998

Intersensory redundancy facilitates learning of arbitrary relations between vowel sounds and objects in seven-month-old infants.

This study investigated 7-month-old infants' ability to relate vowel sounds with objects when intersensory redundancy was present versus absent. Infants (N = 48) were habituated to two alternating video-films of vowel-object pairs in one of three conditions. In the moving-synchronous condition, where redundancy was present, the movement of one object was temporally coordinated with the spoken vowel /a/ and that of the other with /i/, simulating showing and naming the objects to the infant. In the still and in the moving-asynchronous conditions, where redundancy was absent, infants saw static objects, and objects moving out of synchrony with the vowel sounds, respectively. The results indicated that infants detected a mismatch in the vowel-object pairs in the moving-synchronous condition but not in the still or the moving-asynchronous condition. These findings demonstrate that temporal synchrony between vocalizations and the motions of an object facilitates learning of arbitrary speech-object relations, an important precursor to the development of lexical comprehension in infancy.

Attention↗
PubMed1990

The pattern of population growth as a function of redundancy and repair.

A basic model of hierarchical structure, expressed by simple, linear differential equations, shows that the pattern of population growth is essentially determined by conditions of redundancy in the sub-structure of individuals. There does not exist any possible combination between growth rate and accident rate that could balance population numbers and/or the level of redundancy within the population; all possible combinations either lead to extinction or to positive population growth with a decline of the fraction of individuals with redundant substructure. Declining populations, however, can be held fluctuating between certain limits by periodic phases of sub-unit repair. These results are particularly pertinent to the population dynamics of diploid (polyploid) organisms.

DNA Repair↗
PubMed1980

Length determination of the terminal redundant regions in the DNA of phage T7.

The length of the terminal redundant regions in T7 DNA has been determined by two methods. One involved the specific labeling and isolation of the redundant DNA fragment and determination of the molecular weight by polyacrylamide gel electrophoresis. A value of 150 +/- 10 nucleotide pairs was obtained. The other determination based on a correlation of the melting temperature of the redundant region to that of whole T7 DNA confirmed the result obtained by the first method.

Base Sequence↗
PubMed1984

Redundancy reducing processes in single neurons.

Interaction mechanisms between excitatory and inhibitory impulse sequences operating on neurons play an important role for the processing of information by the nervous system. For instance, the convergence of excitatory and inhibitory influences on retinal ganglion cells to form their receptive fields has been taken as an example for the process of neuronal sharpening by lateral inhibition. In order to analyze quantitatively the functional behavior of such a system, Shannon's entropy method for multiple access channels has been applied to biological two-inputs-one-output systems using the theoretical model developed by Tsukada et al. (1979). Here we give an extension of this procedure from the point of view to reduce redundancy of information in the input signal space of single neurons and attempt to obtain a new interpretation for the information processing of the system. The concept for the redundancy reducing mechanism in single neurons is examined and discussed for the following two processes. The first process is concerned with a signal space formed by superposing two random sequences on the input of a neuron. In this process, we introduce a coding technique to encode the inhibitory sequence by using the timing of the excitatory sequence, which is closely related to an encoding technique of multiple access channels with a correlated source (Marko, 1966, 1970, 1973; Slepian and Wolf, 1973) and which is an invariant transformation in the input signal space without changing the information contents of the input. The second process is concerned with a procedure of reducing redundant signals in the signal space mentioned before.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

The problem of redundancy in movement control: the adaptive model theory approach.

The problem of redundancy in movement control is encountered when one attempts to answer the question: How does the central nervous system (CNS) determine the pattern of neural activity required in some 5,000,000 descending motor fibres to control only 100-150 biomechanical degrees of freedom of movement? Mathematically this is equivalent to solving a set of simultaneous equations with many more unknowns than equations. This system of equations is redundant because it has an infinite number of possible solutions. The problem is solved by the neuronal circuitry hypothesized in Adaptive Model Theory (AMT). According to AMT, the CNS includes neuronal circuitry able to compute and maintain adaptively the accuracy of internal models of the reciprocal multivariable relationships between outgoing motor commands and their resulting sensory consequences. To identify these input-output relationships by means of regression analysis, correlations between the input signals have to be taken into account. For example, if the inputs are perfectly correlated, the model reduces to a virtual one-input system. In general, the number of inputs modelled equals the number of degrees of freedom encoded by the signals; that is, the number of independently varying (orthogonal) signals. The adaptive modelling circuitry proposed in AMT automatically tunes itself to extract independently varying sensory and motor signals before computing the dynamic relationships between them. Inverse models are employed during response execution to translate movements pre-planned as desired trajectories of these high-level sensory-feature signals into appropriately co-ordinated motor commands to send to the muscles. Since movement is pre-planned in terms of a number of orthogonalized sensory-feature signals equal to the number of degrees of freedom in the desired response, the problem of redundancy is solved and the correlation or co-ordination between motor-command signals is automatically introduced by the adaptive models.

Biomechanical Phenomena↗
PubMed1987

Separating the redundancy of voicing from nasality in American English.

This paper reports the results of a study designed to separate the voicing redundancy from nasality in American English and to determine their individual saliencies. Sixty-seven subjects judged the similarity of nonnasal pairs versus nasal pairs of CV and VC nonsense syllables on a 5-point magnitude-estimation task. The 80 stimuli were constructed to control and to demand subjects' cognitive strategies for coping with redundancy rather than experimental manipulation of the data. They were developed from the consonantal repertoire of (b d g m n p t k) paired with the vowels (i a u), totaling 72 pairs of dyads. Eight additional stimuli of similar structure, testing multifeature and identity contrasts, were included to monitor the validity of the experimental procedure. Results indicated that speech redundancy can be circumvented cognitively, nasality was more salient (different) than voicing, and a recency effect was found. These findings are discussed in reference to existing data.

Cognition↗
PubMed1989

Pneumatosis coli: is there a relationship with sigmoid colon redundancy?

Pneumatosis coli (PC) is a process characterized by gas-filled cysts in the wall of the large intestine. The barium enema examinations of 14 patients with idiopathic PC were assessed: 93% involved the sigmoid colon, and 84% of patients with sigmoid pneumatosis had sigmoid colon redundancy in comparison to 14% of the control population (p less than 0.001). It is proposed that the sigmoid cysts result in redundancy by affecting the mesentery and colon length. This redundancy may account for the increased risk of sigmoid volvulus in this condition.

Barium Sulfate↗
PubMed2004

Sexual selection, redundancy and survival of the most beautiful.

A model is described of a highly redundant complex organism that has overlapping banks of genes such that each vital function is specified by several different genetic systems. This generates a synergistic profile linking probability of survival to the number of deleterious mutations in the genome. Computer models show that there is a dynamic interaction between the mean number of new deleterious mutations per generation (X), the mean number of deleterious mutations in the genome of the population (Y) and percentage zygote survival (Zs). Increased X leads to increased Y and a fall in Zs but it takes several generations before a new equilibrium is reached. If sexual attraction is influenced by the number of deleterious mutations in the genome of individuals then Y is reduced and Zs increased for any given value of X. This fall in Y and rise in Zs is more marked in polygamous than monogamous mating systems. The model is specified such that deleterious mutations can occur without any observable or measurable effect on function. Thus sexual selection, in this organism, for low levels of deleterious mutations cannot be based on assessment of performance. Instead it is based on a simple symmetrical surface pattern that is flawlessly reproduced by organisms with no deleterious mutations, but is less than perfect, and therefore less attractive, if genetic systems have been deleted. A complex vital task requires a system with a high level of redundancy that acts so that the loss of one component has no observable effect and therefore cannot be used for sexual selection. The reproduction of a beautiful surface pattern also requires a low error, high redundancy genetic system; however, in this case there is advantage if a single deleterious mutation produces a recognisable change. This leads to the conclusion that sexual selection and sexual attraction should be based on beauty rather than utility, and explains the common observation in nature that it is the most beautiful that survive.

Animals↗
PubMed2004

The role of the magnocellular and parvocellular systems in the redundant target effect.

The redundant target effect (RTE) consists in the speeding of reaction time with single versus multiple targets and can be explained either by a neural coactivation or by a race model. To try to understand the role of the magnocellular and parvocellular systems in the determination of the RTE we carried out three experiments using onset or feature singletons. The former are likely to be mainly processed by the magnocellular system while the latter are mainly processed by the parvocellular system. In experiment 1 we found an RTE both when the target (red disk) was presented in isolation and when it was surrounded by equiluminant green distractors. Thus, the RTE occurred both with onset and feature singletons. However, with the former, the RTE could be accounted for by neural coactivation while with the latter it could be accounted for by a probabilistic explanation. In experiment 2 we tried to ascertain the role of distractors in yielding a probabilistic RTE: we used either targets in isolation or surrounded by distractors of lower luminance and found an RTE that could be explained by neural coactivation for both kinds of targets. This ruled out an effect of distractors per se in determining a probabilistic RTE. Finally, in experiment 3 we used targets of lower luminance than either the background or the distractors. We found that the RTE could be accounted for by neural coactivation with targets alone while it was probabilistic with distractors. Overall, these results show that stimuli presumably processed by the magnocellular system yield redundancy gains that result from a neural coactivation mechanism. In contrast, stimuli presumably processed by the parvocellular system are compatible with a probabilistic redundancy gain.

Adult↗
PubMed2006

The role of kinematic redundancy in adaptation of reaching.

Although important differences exist between learning a new motor skill and adapting a well-learned skill to new environmental constraints, studies of force field adaptation have been used frequently in recent years to identify processes underlying learning. Most of these studies have been of reaching tasks that were each hand position was specified by a unique combination of joint angles. At the same time, evidence has been provided from a variety of tasks that the central nervous system takes advantage of the redundancy available to it when planning and executing functional movements. The current study attempted to determine whether a change in the use of joint motion redundancy is associated with the adaptation process. Both experimental and control subjects performed 160 trials of reaching in each of four adaptation phases, while holding the handle of a robot manipulandum. During the first and last adaptation phases, the robot motors were turned off. During phases 2 and 3 the motors produced a velocity-dependent force field to which experimental subjects had to adapt to regain relatively straight line hand movements during reaching to a target, while the motors remained off for the control group. The uncontrolled manifold (UCM) method was used to partition the variance of planar clavicle-scapular, shoulder, elbow and wrist joint movements into two orthogonal components, one (V(UCM)) that reflected combinations of joint angles that were equivalent with respect to achieving the average hand path and another (V(ORT)) that took the hand away from its average path. There was no change in either variance component for the control group performing 640 non-perturbed reaches across four 'pseudo-adaptation' phases. The experimental group showed adaptation to reaching in the force field that was accompanied initially by an increase in both components of variance, followed by a smaller decrease of V(UCM) than V(ORT) during 320 practice reaches in the force field. After initial re-adaptation to reaching to the null field, V(UCM) was higher in experimental than in control subjects after performing a comparable number of reaches. V(UCM) was also larger in the experimental group after re-adaptation when compared to the 160 null field reaching trials performed prior to initial force field introduction. The results suggest that the central nervous system makes use of kinematic redundancy, or flexibility of motor patterns, to adapt reaching performance to unusual force fields, a fact that has implications for the hypothesis that motor adaptation requires learning of formal models of limb and environmental dynamics.

Adaptation, Physiological↗
PubMed2003

Interspecies comparison of a gene pair with partially redundant function: the rst and kirre genes in D. virilis and D. melanogaster.

The D. melanogaster rst and kirre genes encode two highly related immunoglobulin-like cell adhesion molecules that function redundantly during embryonic muscle development. The two genes appear to be derived from a common ancestor by gene duplication. Gene duplications have been proposed to be of major evolutionary significance since duplicated redundant sequences can accumulate mutations without detrimental effects for the organism and leave the duplicated genes free to assume novel functions. To address the issue of conservation of the duplicated sequences and their putative redundancy, as well as to identify putative functional divergence of the paralogs during drosophilid evolution, we performed an interspecies comparison of the rst and kirre genes from D. virilis and D. melanogaster. The D. virilis genome contains orthologues of both rst and kirre and hence the duplication took place before the split of the two lineages and has subsequently been conserved. However, whilst the Rst orthologues show a high degree of sequence similarity, this similarity is lower in Kirre orthologues. Especially the intracellular domains of D. virilis and D. melanogaster Kirre sequences are highly divergent: the D. virilis kirre gene lacks the 3'-most exon present in D. melanogaster, which contains motifs conserved between kirre and rst in D. melanogaster. Hence, while each of the two genes is highly conserved at the level of its exon-intron organization, the selection forces acting on the rst and kirre coding sequences are different. These findings are discussed in the light of general evolutionary mechanisms.

Amino Acid Sequence↗
PubMed2005

Redundant and distinct functions of the ABA response loci ABA-INSENSITIVE(ABI)5 and ABRE-BINDING FACTOR (ABF)3.

Abscisic acid-responsive gene expression is regulated by numerous transcription factors, including a subgroup of basic leucine zipper factors that bind to the conserved cis-acting sequences known as ABA-responsive elements. Although one of these factors, ABA-insensitive 5 (ABI5), was identified genetically, the paucity of genetic data for the other family members has left it unclear whether they perform unique functions or act redundantly to ABI5 or each other. To test for potential redundancy with ABI5, we identified the family members with most similar effects and interactions in transient expression systems (ABF3 and ABF1), then characterized loss-of-function lines for those loci. The abf1 and abf3 monogenic mutant lines had at most minimal effects on germination or seed-specific gene expression, but the enhanced ABA- and stress-resistance of abf3 abi5 double mutants revealed redundant action of these genes in multiple stress responses of seeds and seedlings. Although ABI5, ABF3, and ABF1 have some overlapping effects, they appear to antagonistically regulate each other's expression at specific stages. Consequently, loss of any one factor may be partially compensated by increased expression of other family members.

Abscisic Acid↗
PubMed1993

Redundant clothing: a readily observable marker for schizophrenia in the psychiatric emergency room population.

Most mental health workers have seen bizarrely dressed patients who wear multiple pieces of some item of clothing. Since many of these patients carried a schizophrenic diagnosis, we devised a study to test whether redundant clothing is a reliable indicator of schizophrenia. Of 25 patients who presented at the city psychiatric emergency room wearing redundant clothes, 18 received schizophrenic diagnoses. A Chi square analysis comparing proportions attained significance at the P < .0001 level. Although not a particularly sensitive measure, wearing redundant clothes appears to be a readily observable behavior associated with schizophrenia in the psychiatric emergency room.

Clothing↗