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PubMed2004

Do dietary intakes affect search for nutrient information on food labels?

Nutrition labels on food packages are designed to promote and protect public health by providing nutrition information so that consumers can make informed dietary choices. High levels of total fat, saturated fat and cholesterol in diets are linked to increased blood cholesterol levels and a greater risk of heart disease. Therefore, an understanding of consumer use of total fat, saturated fat, and cholesterol information on food labels has important implications for public health and nutrition education. This study explores the association between dietary intakes of these three nutrients and psychological or demographic factors and the search for total fat, saturated fat, and cholesterol information on food labels. Psychology literature suggests a negative association between intakes of these nutrients and probability of search for their information on food labels. Health behavior theories also suggest perceived benefits and costs of using labels and perceived capability of using labels are associated with the search behavior. We estimate the relationship between label information search and its predictors using logistic regressions. Our samples came from the 1994-1996 Continuing Survey of Food Intakes by Individuals and Diet and Health Knowledge Survey conducted by the United States Department of Agriculture. Results suggest that search for total fat, saturated fat, and cholesterol information on food labels is less likely among individuals who consume more of the three nutrients, respectively. The search is also related to perceived benefits and costs of using the label, perceived capability of using the label, knowledge of nutrition and fats, perceived efficacy of diets in reducing the risk of illnesses, perceived importance of nutrition in food shopping, perceived importance of a healthy diet, and awareness of linkage between excessive consumption of the nutrients and health problems. These findings suggest encouraging search of food label information among consumers with unhealthy dietary habits would need innovative approaches. Yet, nutrition education can be instrumental in encouraging this search by stimulating motivation and providing technical help.

Adult↗
PubMed1997

Spatial memory deficits in patients with unilateral damage to the right hippocampal formation.

Patients with unilateral temporal lobe damage resulting from intractable temporal lobe epilepsy (TLE, n = 30) or from temporal lobe resection (temporal lobectomy, TLR, n = 47) were investigated on the Nine-box Maze. The task, analogous to the radial arm maze, was designed to compare spatial mapping and working memory theories of the functions of the hippocampus. The task provides measures of spatial, object, working and reference memory, incorporated into a within subjects design. The spatial component was designed to encourage the formation of allocentric rather than egocentric spatial representations. Spatial memory deficits were found (across working and reference memory components) in both TLE and TLR patients with right temporal lobe damage, with intact spatial memory in patients with corresponding left temporal lobe damage. Performance on the matched non-spatial (object) working memory component was equal to healthy controls for all groups. However all patient groups showed a deficit on object reference memory. These findings are discussed in relation to the underlying temporal lobe pathology and particularly atrophy of the hippocampal formation. Overall, the results support the cognitive mapping theory of hippocampal function, with the demonstration of a selective (and probably allocentric) spatial memory deficit in patients with right hippocampal damage.

Adolescent↗
PubMed1998

An information typology for understanding living systems.

It is argued that we can improve our understanding of living systems by focusing on their informational processes. Recent developments, primarily in evolutionary biology, cybernetics and systems theory, suggest that informational processes are of at least two, and probably three, different types; and that the interaction of these types can be seen as a basis for the self-construction of living systems. Following the work of Csanyi and Kampis, a distinction is drawn between referential and nonreferential information. This typology is further extended to include statereferential information. The statereferential type serves to lend stability to informational arrangements (organization) that are viable so that they may be propagated in space and time.

Information Science↗
PubMedDate not supplied

Event-based categorical sequential analyses of the medical interview: a review.

When the doctor-patient interaction is viewed as a series of utterances, the temporal position of utterances becomes a central information in understanding the nature of interaction. Important concepts are interdependence and serial dependence which account for the fact that two partners influence each other in their talk and that each partner influences him/herself. Lag sequential analysis studies the associations between doctor and patient utterances in a two-way contingency table (lag one sequences) and is used for exploratory purposes. Long-linear modelling, based on multi-way contingency tables, is used as an extension of lag-sequential analysis to study longer sequences. Markov chains test sequences in terms of processes with the aim to find predictive models and require a theory driven approach. Pattern recognition aims to discover regularities in the temporal evolution of the utterance sequences. Theory driven applications analyse manifest patterns in terms of their conditional probability distribution while empirically driven applications are used to detect "hidden" patterns. These different approaches to sequential data can be regarded as complementary tools to describe the doctor patient consultations at various levels of complexity.

Communication↗
PubMed2002

Measuring and modeling the trajectory of visual spatial attention.

In a novel choice attention-gating paradigm, observers monitor a stream of 3 x 3 letter arrays until a tonal cue directs them to report 1 row. Analyses of the particular arrays from which reported letters are chosen and of the joint probabilities of reporting pairs of letters are used to derive a theory of attention dynamics. An attention window opens 0.15 s following a cue to attend to a location, remains open (minimally) 0.2 s, and admits information simultaneously from all the newly attended locations. The window dynamics are independent of the distance moved. The theory accounts for about 90% of the variance from the over 400 data points obtained from each of the observers in the 3 experiments reported here. With minor elaborations, it applies to all the principal paradigms used to study the dynamics of visual spatial attention.

Adult↗
PubMed2002

Semantic interference from objects both in and out of a scene context.

Prior studies have found that, despite the intentions of the participants, objects automatically activate their semantic representations; however, this research examined only objects presented in isolation without a background context. The present set of experiments examined the automaticity issue for objects presented in isolation as well as in scenes. In Experiments 1 and 2, words were categorized more slowly when they were embedded inside incongruent objects (e.g., the word chair in a picture of a duck) than inside neutral nonobjects, suggesting that the meanings of the objects were activated despite participants' intentions. A new interference task was introduced in Experiment 3. When the same objects and words from the first 2 experiments were inserted into scenes in which those objects were probable or improbable, interference occurred from probable pictured objects but not from improbable pictured objects. Implications for theories of automaticity and models of object identification are discussed.

Association Learning↗
PubMed1988

Extra-pair copulation and sperm competition in the zebra finch.

Most birds are monogamous, but recent studies have shown that extra-pair copulations (EPCs) occur frequently despite a range of paternity guards, including mate-guarding and frequent copulation. Although EPCs are known to result in extra-pair paternity, there are no previous quantitative estimates of the success of EPCs in fertilizing eggs. We present here estimates of the likelihood of success of extra-pair copulations in a monogamous passerine, the zebra finch Poephila guttata. We show that (1) EPCs occurring under semi-natural conditions in captivity result in extra-pair paternity, (2) sperm from the last male to mate has precedence over previous matings: a single EPC occurring last is disproportionately successful in fertilizing eggs, but EPCs followed by further pair copulations have a low probability of success. These results have important implications for sexual selection theory.

Animals↗
PubMed2002

Plant sex determination and sex chromosomes.

Sex determination systems in plants have evolved many times from hermaphroditic ancestors (including monoecious plants with separate male and female flowers on the same individual), and sex chromosome systems have arisen several times in flowering plant evolution. Consistent with theoretical models for the evolutionary transition from hermaphroditism to monoecy, multiple sex determining genes are involved, including male-sterility and female-sterility factors. The requirement that recombination should be rare between these different loci is probably the chief reason for the genetic degeneration of Y chromosomes. Theories for Y chromosome degeneration are reviewed in the light of recent results from genes on plant sex chromosomes.

Evolution, Molecular↗
PubMed2002

Glandular patterns in a thyroid carcinoma with insular and anaplastic features: a case with possible implications for the classification of thyroid carcinomas.

We describe the case of a 33-year-old woman with a thyroid carcinoma showing poorly differentiated (insular), anaplastic, and glandular features, the latter with extensive clear cell changes. Grossly, the well-circumscribed tumor nodule measured 3.6 cm in maximum dimension and was confined to the thyroid. Microscopically, the majority of the tumor was composed of well-defined "insular" nests showing microfollicular formation, high mitotic activity, and areas of necrosis. Other regions, as well as the intervening stroma of the insular nests, were characterized by highly atypical and pleomorphic stromal cells, extensive necrosis, and malignant cartilaginous nodules. Approximately 30% of the tumor was composed of diffuse glandular formations, each of which were lined by elongated, simple columnar cells with basally situated, mildly pleomorphic nuclei, clear supranuclear, periodic acid-Schiff + (and diastase sensitive) cytoplasm, empty lumens, and no myoepithelia or basement membranes. Immunohistochemically, the glandular elements displayed diffuse and strong positivity for thyroid transcription factor-1, bcl-2, and CAM 5.2, sparse positivity for thyroglobulin and Ki67, and diffuse but weak positivity for p53. Calcitonin was negative throughout the tumor. Karyotypic analysis of a primary culture showed a complex hypertriploid karyotype including structural abnormalities of chromosomes X, 1, 4, 6, 9, 13, and 14 in the majority of cells examined. This composite of histologic findings, especially the glandular patterns, is unusual and their prognostic significance is unclear. The patient is alive with no evidence of tumor recurrence or metastasis at 5 months follow-up. Overall, the morphologic and immunohistochemical properties of the glandular component suggests that they are less differentiated than well-differentiated carcinomas and are probably more differentiated than the insular component. This case supports the theory that the various primary carcinomas of the thyroid may represent points along a spectrum rather than distinct entities.

Adult↗
PubMed2005

Absolute rate theories of epigenetic stability.

Spontaneous switching events in most characterized genetic switches are rare, resulting in extremely stable epigenetic properties. We show how simple arguments lead to theories of the rate of such events much like the absolute rate theory of chemical reactions corrected by a transmission factor. Both the probability of the rare cellular states that allow epigenetic escape and the transmission factor depend on the rates of DNA binding and unbinding events and on the rates of protein synthesis and degradation. Different mechanisms of escape from the stable attractors occur in the nonadiabatic, weakly adiabatic, and strictly adiabatic regimes, characterized by the relative values of those input rates.

DNA↗
PubMed1981

Effect of nonspecific forces and finite receptor number on rate constants of ligand--cell bound-receptor interactions.

We develop a theory of ligand diffusion in the presence of a central potential toward or away from receptor patches that are uniformly distributed over a spherical cell. The current onto the receptors is reduced to less than that onto the sphere by a factor that is a nonlinear function of the number of free receptors, their size, and their potential energy. Similarly, under conditions defined by the theory, the dissociation rate from a receptor is reduced by the probability of rebinding to some other receptor on the same cell. This complicates the kinetic analysis, leading to the possibility of an occupancy-dependent dissociation rate, but has no effect on the interpretation of thermodynamic data.

Cell Membrane↗
PubMed1988

Current versus historical population sizes in vertebrate species with high gene flow: a comparison based on mitochondrial DNA lineages and inbreeding theory for neutral mutations.

Using inbreeding theory as applied to neutral alleles inherited maternally, we generate expected probability distributions of times to identity by descent for random pairs of mitochondrial genotypes within a population or within an entire species characterized by high gene flow. For comparisons with these expectations, empirical distributions of times to most recent common ancestry were calculated (by conventional mtDNA clock calibrations) from mtDNA haplotype distances observed within each of three vertebrate species--American eels, hardhead catfish, and redwinged blackbirds. These species were chosen for analysis because census population size in each is currently large and because both genetic and life-history data are consistent with the postulate that historical gene flow within these species has been high. The observed molecular distances among mtDNA lineages were two to three orders of magnitude lower than predicted from census sizes of breeding females, suggesting that rate of mtDNA evolution is decelerated in these species and/or that long-term effective population size is vastly smaller than present-day population size. Several considerations point to the latter possibility as most likely. The genetic structure of any species is greatly influenced by historical demography; even for species that are currently abundant, mtDNA gene lineages appear to have been channeled through fairly small numbers of ancestors.

Animals↗
PubMedDate not supplied

Effects of multi-talker competing speech on the variability of the California Consonant Test.

The interference effects of multi-talker speech babble on the California Consonant Test scores were examined. Phoneme recognition was assessed in a sound field in quiet and under 4 message-to-competition ratio conditions for normal-hearing subjects and in three MCR conditions for listeners with bilateral high-frequency sensorineural hearing loss. The noise interference functions for both subject groups were characterized by a gradual decline in recognition performance as the signal-to-noise ratio decreased. The slope of the function for the 2 groups was parallel with the mean scores for the hearing-impaired subjects approximately 30% lower than those for the normal hearers. Test-retest reliability across conditions was examined via correlational analysis and by computing test-retest difference scores for individual subjects. These data are discussed in terms of sampling theory for full-list and half-list presentations and probabilities of measurement error for determining significance between 2 scores.

Adolescent↗
PubMed2001

Chaos-assisted tunneling with cold atoms.

In the context of quantum chaos, both theory and numerical analysis predict large fluctuations of the tunneling transition probabilities when irregular dynamics is present at the classical level. Here we consider the nondissipative quantum evolution of cold atoms trapped in a time-dependent modulated periodic potential generated by two laser beams. We give some precise guidelines for the observation of chaos-assisted tunneling between invariant phase space structures paired by time-reversal symmetry.

Journal Article↗
PubMed2006

Continuous probabilistic approach to species dynamics in Hubbell's zero-sum local community.

In this paper a continuous probabilistic approach formulated using Kolmogorov-Fokker-Planck forward and backward models is applied to Hubbell's zero-sum neutral theory for species dynamics in local community. Using this technique the probability density of species abundance, distribution of the first passage time to extinction or fixation and probability of extinction are defined. The resulting values for the distribution of the first passage time to extinction are verified by the simulation study of Hubbell's zero-sum neutral model for the local community. Based on the sensitivity analysis for the continuous probabilistic models, the realistic classification of local communities subject to their diversity and species dynamics is proposed with respect to the immigration probability, the species metacommunity relative abundance, and the size of local community.

Computer Simulation↗
PubMed2000

Network robustness and fragility: percolation on random graphs.

Recent work on the Internet, social networks, and the power grid has addressed the resilience of these networks to either random or targeted deletion of network nodes or links. Such deletions include, for example, the failure of Internet routers or power transmission lines. Percolation models on random graphs provide a simple representation of this process but have typically been limited to graphs with Poisson degree distribution at their vertices. Such graphs are quite unlike real-world networks, which often possess power-law or other highly skewed degree distributions. In this paper we study percolation on graphs with completely general degree distribution, giving exact solutions for a variety of cases, including site percolation, bond percolation, and models in which occupation probabilities depend on vertex degree. We discuss the application of our theory to the understanding of network resilience.

Algorithms↗
PubMed2003

Fluctuations of g factors in metal nanoparticles: effects of electron-electron interaction and spin-orbit scattering.

We investigate the combined effect of spin-orbit scattering and electron-electron interactions on the probability distribution of g factors of metal nanoparticles. Using random matrix theory, we find that even a relatively small interaction strength significantly increases g-factor fluctuations for not-too-strong spin-orbit scattering (ratio of spin-orbit rate and single-electron level spacing 1/tau(so)delta < or near 1), and leads to the possibility to observe g factors larger than 2.

Journal Article↗