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At least 433 records · Page 24Linked to original sources
PubMed2006

Distribution of care information packages for the support of patients with cancer and their families during disaster situations and their evaluation via the internet.

With the aim of preparing for disasters, care information packages for the support of patients with cancer and their families during disaster situations were developed in our previous study, and were provided via the internet with a questionnaire asking the face validity and the usefulness of such information. Thirty replies were received. Most subjects thought the care packages were appropriate and useful in the actual settings, however 43.3% of them thought the amount of information was excessive. Many comments and suggestions on the care information packages also could be obtained via the internet.

Disasters↗
PubMedDate not supplied

Using objective and subjective information to develop distributions for probabilistic exposure assessment.

The propagation of variance through complex exposure models has been simplified by simulation software running on desktop computers; however, the appropriate representation of variability in, and uncertainty about, model inputs remains a challenge. The U.S. Environmental Protection Agency (EPA) has indicated that the Monte Carlo simulation approach to exposure assessment is acceptable as long as input distributions are credible, i.e., rooted in fact (EPA, 1992). The use of distributions based on empirical evidence is certainly desirable; however, it is not always possible to obtain measurements for all exposure model inputs under the conditions of interest. Where objective evidence is scarce or unavailable, subjective judgments are necessary. In this work, the application of both statistical and subjective approaches to the development of distributions for exposure model inputs is explored. The consequences of one's approach to distribution development, on the interpretation and applicability of the output, are also considered.

Data Interpretation, Statistical↗
PubMed1999

Firing rate distributions and efficiency of information transmission of inferior temporal cortex neurons to natural visual stimuli.

The distribution of responses of sensory neurons to ecological stimulation has been proposed to be designed to maximize information transmission, which according to a simple model would imply an exponential distribution of spike counts in a given time window. We have used recordings from inferior temporal cortex neurons responding to quasi-natural visual stimulation (presented using a video of everyday lab scenes and a large number of static images of faces and natural scenes) to assess the validity of this exponential model and to develop an alternative simple model of spike count distributions. We find that the exponential model has to be rejected in 84% of cases (at the p < 0.01 level). A new model, which accounts for the firing rate distribution found in terms of slow and fast variability in the inputs that produce neuronal activation, is rejected statistically in only 16% of cases. Finally, we show that the neurons are moderately efficient at transmitting information but not optimally efficient.

Animals↗
PubMed2006

Optimal movement between patches under incomplete information about the spatial distribution of food items.

If the food distribution contains spatial pattern, the food density in a particular patch provides a forager with information about nearby patches. Foragers might use this information to exploit patchily distributed resources profitably. We model the decision on how far to move to the next patch in linear environments with different spatial patterns in the food distribution (clumped, random, and regular) for foragers that differ in their degree of information. An ignorant forager is uninformed and therefore always moves to the nearest patch (be it empty or filled). In contrast, a prescient forager is fully informed and only exploits filled patches, skipping all empty patches. A Bayesian assessor has prior knowledge about the content of patches (i.e. it knows the characteristics of the spatial pattern) and may skip neighbouring patches accordingly by moving to the patch where the highest gain rate is expected. In most clumped and regular distributions there is a benefit of assessment, i.e. Bayesian assessors achieve substantially higher long-term gain rates than ignorant foragers. However, this is not the case in distributions with less strong spatial pattern, despite the fact that there is a large potential benefit from a sophisticated movement rule (i.e. a large penalty of ignorance). Bayesian assessors do also not achieve substantially higher gain rates in environments that are relatively rich or poor in food. These results underline that an incompletely informed forager that is sensitive to spatial pattern should not always respond to existing pattern. Furthermore, we show that an assessing forager can enhance its long-term gain rate in highly clumped and some specific near-regular food distributions, by sampling the environment in slightly larger spatial units.

Animals↗
PubMed2002

Does a powder surface contain all necessary information for particle size distribution analysis?

The aim of this study was to utilise a new approach where digital image information is used in the characterisation of particle size distributions of a large set of pharmaceutical powders. A novel optical set-up was employed to create images and calculate a stereometric parameter from the digital images of powder surfaces. Analysis was made of 40 granule batches with varying particle sizes and compositions prepared with fluidised bed granulation. The extracted digital image information was then connected to particle size using multivariate modelling. The modelled particle size distributions were compared to particle size determinations with sieve analysis and laser diffraction. The results revealed that the created models corresponded well with the particle size distributions measured with sieve analysis and laser diffraction. This study shows that digital images taken from powder surfaces contain all necessary data that is needed for particle size distribution analysis. To obtain this information from images careful consideration has to be given on the imaging conditions. In conclusion, the results of this study suggest that the new approach is a powerful means of analysis in particle size determination. The method is fast, the sample size needed is very small and the technique enables non-destructive analysis of samples. The method is suitable in the particle size range of approximately 20-1500 microm. However, further investigations with a broad range of powders have to be made to obtain information of the possibilities and limitations of the introduced method in powder characterisation.

Particle Size↗
PubMed2002

How distributed is visual category information in human occipito-temporal cortex? An fMRI study.

We used fMRI to study the distribution of object category information in the ventral visual pathway. Extending the findings of, we find that categories of stimuli can be distinguished by the pattern of activation they elicit across this entire pathway, even when the stimuli within a category differ in viewpoint, exemplar, or image format. However, regions within the ventral visual pathway are neither interchangeable nor equipotential. Although the FFA and PPA permit excellent discrimination between preferred versus nonpreferred stimuli (e.g., faces-bottles and houses-bottles, respectively), we find that neither region alone permits accurate discrimination between pairs of nonpreferred stimuli (e.g., bottles-shoes). These findings indicate that the ventral visual pathway is not homogeneous, but contains some regions (including FFA and PPA) that are primarily involved in the analysis of a single class of stimulus.

Evoked Potentials, Visual↗
PubMed1997

The Canadian Cooperative Wildlife Health Centre and surveillance of wild animal diseases in Canada.

The Canadian Cooperative Wildlife Health Centre (CCWHC) was established in 1992 as an organization among Canada's 4 veterinary colleges, with a mandate to apply veterinary medicine to wildlife management and conservation in Canada. A major function of the CCWHC is nation-wide surveillance of wild animal diseases. Disease surveillance is conceived as consisting of 4 different activities: detection, diagnosis, information management, and use of information. In the CCWHC surveillance program, detection of disease is carried out by a wide range of professional and avocational field personnel, and much effort is expended to stimulate and support this activity. Diagnosis is done by personnel of provincial and federal veterinary laboratories and the CCWHC. Information management is achieved through a national database of wildlife disease incidents developed and maintained by the CCWHC. Use of information is enabled through established channels for distribution of information derived from the surveillance program to persons responsible for wildlife programs and policies, and to the public. There has been a high demand for the services of the CCWHC since its establishment. The CCWHC responds to approximately 2000 requests for information annually, distributes its newsletter to over 1700 recipients, examines approximately 1200 wild animal submissions each year, and has accumulated records of over 5000 disease incidents in its database. Technical information from the CCWHC has benefited federal, provincial/territorial, and nongovernment wildlife agencies; endangered species recovery programs; federal and provincial veterinary services; and federal and provincial public health programs.

Animal Diseases↗
PubMed2002

A straw man proposal for a quantitative definition of the RfD.

This paper discusses the merits and disadvantages of a specific proposal for a numerical calculation of the reference dose (RfD) with explicit recognition of both uncertainty and variability. It is suggested that the RfD be the lower (more restrictive) value of: The daily dose rate that is expected (with 95% confidence) to produce less than 1/100,000 incidence over background of a minimally adverse response in a standard general population of mixed ages and genders, or The daily dose rate that is expected (with 95% confidence) to produce less than a 1/1000 incidence over background of a minimally adverse response in a definable sensitive subpopulation. Developing appropriate procedures to make such estimates poses challenges. To be a viable replacement for current RfDs, a numerical definition needs to be A plausible representation of the risk management values that both lay people and "experts" believe are intended to be achieved by current RfDs, (while better representing the "truth" that current RfDs cannot be expected to achieve zero risk with absolute confidence for a mixed population with widely varying sensitivities), Estimable with no greater amount of chemical specific information than is traditionally collected to estimate current RfD values, Subjected to a series of comparisons with existing RfDs to evaluate overall implications for current regulatory values, A more flexible value in the sense of facilitating the development of procedures to allow the incorporation of more advanced technical information--e.g., defined data on human distributions of sensitivity; information on comparative pharmacokinetic and/or pharmacodynamics in humans vs. test species, etc. The discussion evaluates the straw man proposal in the light of each of these points, and assesses the risks and uncertainties inherent in present RfDs by applying existing distributional information on various uncertainty factors to 18 of 20 randomly-selected entries from IRIS. The analysis here suggests that current RfDs seem to meet the 1/100,000 risk criterion with only somewhat better than 50% confidence. However, the current RfDs appear to generally fall short of the goal of meeting this risk criterion with 95% confidence, typically by an order of magnitude in dose or somewhat more. The single most important uncertainty is the extent of human interindividual variability in the doses of specific chemicals that cause adverse responses. Our major conclusion is that with some important assumptions, it is currently feasible to both specify quantitative probabilistic performance objectives for RfDs and to make tentative assessments about whether specific current RfDs for real chemicals seem to meet those objectives. Similarly it is also possible to make preliminary estimates of how much risk is posed by exposures in the neighborhood of current RfDs, and what the uncertainties are in such estimates. It is therefore possible to harmonize cancer and noncancer risk assessments by making quantitative noncancer risk estimates comparable to those traditionally made for carcinogenic risks. The benefits from this change will be an increase in the candor of public discussion of the possible effects of exposures to chemicals posing non-cancer risks, and encouragement for the collection of better scientific information related to toxic risks in people--particularly the extent and distributional form of interindividual differences among people in susceptibility.

Animals↗
PubMed2001

Consistent integration of non-reliable heterogeneous information resources applied to the annotation of transmembrane proteins.

Information agents integrate multiple distributed heterogeneous information sources. The challenging yet unsolved problem that remains, is to ensure the semantic consistency of the integrated data. In this paper we set out to develop a general approach to inconsistency management for information agents. It is implemented as part of the EDITtoTrEMBL system and applied on a large real-world problem in the domain of bioinformatics.

Amino Acid Sequence↗
PubMed2003

Local information as a resource in distributed quantum systems.

A new paradigm for distributed quantum systems where information is a valuable resource is developed. After finding a unique measure for information, we construct a scheme for its manipulation in analogy with entanglement theory. In this scheme, instead of maximally entangled states, two parties distill local states. We show that, surprisingly, the main tools of entanglement theory are general enough to work in this opposite scheme. Up to plausible assumptions, we show that the amount of information that must be lost during the protocol of concentration of local information can be expressed as the relative entropy distance from some special set of states.

Journal Article↗
PubMed2001

Resolution enhancement in standing-wave total internal reflection microscopy: a point-spread-function engineering approach.

The theoretical basis for resolution enhancement in standing-wave total internal reflection microscopy (SW-TIRM) is examined. This technique relies on the formation of an excitation field containing super-diffraction-limited spatial-frequency components. Although the fluorescence generated at the object planes contains high-frequency information of the object distribution, this information is lost at the image plane, where the detection optics acts as a low-pass filter. From the perspective of point-spread-function (PSF) engineering, one can show that if this excitation field is translatable experimentally, the high-frequency information can be extracted from a set of images where the excitation fields have different displacement vectors. We have developed algorithms to combine this image set to generate a composite image with an effective PSF that is equal to the product of the excitation field and the Fraunhofer PSF. This approach can easily be extended to incorporate nonlinear excitation modalities into SW-TIRM for further resolution improvement. We theoretically examine high-resolution imaging based on the addition of two-photon, pump-probe, and stimulated-emission depletion methods to SW-TIRM and show that resolution better than 1/20 of the emission wavelength may be achievable.

Journal Article↗
PubMedDate not supplied

[Representations of mother to child transmission of AIDS, perception of the risk and health information messages in Burkina Faso].

In Burkina Faso, in rural Mossi areas, popular contemporary representations of the transmission of HIV from mother to child are based on the idea that "the disease is in the blood" and that the fetus is conceived by "mixing the blood" of its parents. Infection of the child is seen as inevitable and systematic and is believed to occur in utero. Maternal milk is thought to have the same potential for infection because "milk is blood" but its role in transmission is seen as secondary, with transmission occurring before birth. However, breast feeding is believed to be responsible for the transmission of the disease in two ways: 1) by infected women transmitting the illness to healthy children via their milk and 2) by healthy women becoming infected by breast feeding infants born to infected mothers. The belief that transmission is systematic and the fear that the child will contaminate others leads to the widely held view within the population that no care should be taken of children born to women with AIDS and that such children should be abandoned and left to die. These representations have recently developed in the population based on preexisting beliefs relating to the physiology and role of blood in the transmission of diseases and the health information that has been distributed. Health information messages are largely responsible for the representations described above. Indeed, the description of the modes of HIV transmission in such messages has been based on the simplified statement of the triad, sex, blood and mother-child, with no indication of the relative risks of transmission for each. Hence, this incomplete information, interpreted in terms of popular conceptions about contagion, has resulted in maximal probability being attributed to each of the listed modes of transmission. Health information messages are the principal means of communicating scientific information to the general population. The stakes associated with the quality and correctness of the information supplied are therefore very high. The notion of the risk of transmission and statement of the level of risk are essential to any explanation of the modes of transmission of HIV. These ideas cannot be neglected because they are essential to the correct understanding of transmission and to the logical management of individual risk.

Acquired Immunodeficiency Syndrome↗
PubMed2006

Photoionization and photodissociation of HCl(B 1Sigma+, J=0) near 236 and 239 nm using three-dimensional ion imaging.

The electronically excited states HCl(*)(E,upsilon(')=0,J(')=0) and HCl(*)(V,upsilon(')=12,J(')=0) have been prepared by two-photon resonant absorption of ground state HCl via Q(0) transitions at 238.719 and at 236.000 nm, respectively. The consequent one-or two-photon excitation at the same wavelength results in the production of H(+), Cl(+), and HCl(+) ions. The speed distributions and anisotropy parameters beta for these ions have been determined by three-dimensional photo-fragment ion imaging based on a position-sensitive delay-line anode assembly. Several results are presented: first, we measured velocity (speed and angle) distributions for HCl(+) due to the electron recoil in the photoionization of HCl(*). Such distributions give information on the photoionization process and on the vibrational distribution of HCl(+) after the laser pulse. Second, the measured beta parameters for Cl(+) and H(+) distributions give information on the symmetries of the upper states in the one-photon photoexcitation of HCl(*). Third, the measured speed distributions for H(+) help to understand the mechanism of the photodissociation of HCl(+) ions.

Journal Article↗
PubMed1997

A federated schema-based middleware architecture for hospital information systems.

An important concern in distributed hospital information systems is the integration of information across heterogeneous subsystems. Consistent data replication is a central problem to be solved in this domain. The specific requirements and problems for integration of information within hospitals are discussed and a middleware architecture which has been designed according to these requirements is presented. Communication servers are often deployed in hospitals to connect heterogeneous subsystems. This paper discusses some problems with this approach and presents a federated schema-based middleware architecture as an alternative solution for propagation of information updates across heterogeneous subsystems within hospitals.

Database Management Systems↗
PubMed1994

Neural ensemble coding in inferior temporal cortex.

1. Isolated, single-neuron extracellular potentials were recorded sequentially in area TE of the inferior temporal cortex (IT) of two macaque monkeys (n = 58 and n = 41 neurons). Data were obtained while the animals were performing a paired-associate task. The task utilized five stimuli and eight stimulus pairings (4 correct and 4 incorrect). Data were evaluated as average spike rate during experimental epochs of 100 or 400 ms. Single-unit and population characteristics were measured using a form of linear discriminant analysis and information theoretic measures. To evaluate the significance of covariance on population code measures, additional data consisting of simultaneous recordings from < or = 8 isolated neurons (n = 37) were obtained from a third macaque monkey that was passively viewing visual stimuli. 2. On average, 43% of IT neurons were activated by any of the stimuli used (60% if those inhibited also are included). Yet the neurons were rather unique in the relative magnitude of their responses to each stimulus in the test set. These results suggest that information may be represented in IT by the pattern of activity across neurons and that the representation is not sparsely coded. It is further suggested that the representation scheme may have similarities to DNA or computer codes wherein a coding element is not a local parametric descriptor. This is a departure from the V1 representation, which appears to be both local and parametric. It is also different from theories of IT representation that suggest a constructive basis set or "alphabet". From this view, determination of stimulus discrimination capacity in IT should be evaluated by measures of population activity patterns. 3. Evaluation of small groups of simultaneously recorded neurons obtained during a fixation task suggests that little information about visual stimuli is conveyed by covariance of activity in IT when a 100-ms time scale is used as in this study. This finding is consistent with a prior report, by Gochin et al., which used a 1-ms time scale and failed to find neural activity coherence or oscillations dependent on stimuli. 4. Population-stimulus-discrimination capacity measures were influenced by the number of neurons and to some extent the number and type of stimuli. 5. Information conveyed by individual neurons (mutual information) averaged 0.26 bits. The distribution of information values was unimodal and is therefore more consistent with a distributed than a local coding scheme.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗