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PubMed2004

Divalproex ER prophylaxis in migraineurs with probable chronic migraine and probable medication-overuse headache: a case series.

This case series prospectively evaluated divalproex ER in 15 headache clinic migraine patients fulfilling International Headache Society criteria for probable chronic migraine and probable medication-overuse headache. Divalproex ER was initiated at 500 mg QHS and increased after Week 2 to 1000 mg QHS for a total treatment period of 2 months. Mean headache days per month dropped from 21.6 to 10.4 at month 1 and 8.9 at month 2. All 10 patients who completed the study rated their satisfaction with treatment as changed from unsatisfied at baseline to satisfied at study completion. The results of this study support the prophylactic efficacy of divalproex ER in migraine patients with probable chronic migraine and probable medication-overuse headache.

Journal Article↗
PubMed2005

What is preexisting strength? Predicting free association probabilities, similarity ratings, and cued recall probabilities.

Measuring lexical knowledge poses a challenge to the study of the influence of preexisting knowledge on the retrieval of new memories. Many tasks focus on word pairs, but words are embedded in associative networks, so how should preexisting pair strength be measured? It has been measured by free association, similarity ratings, and co-occurrence statistics. Researchers interpret free association response probabilities as unbiased estimates of forward cue-to-target strength. In Study 1, analyses of large free association and extralist cued recall databases indicate that this interpretation is incorrect. Competitor and backward strengths bias free association probabilities, and as with other recall tasks, preexisting strength is described by a ratio rule. In Study 2, associative similarity ratings are predicted by forward and backward, but not by competitor, strength. Preexisting strength is not a unitary construct, because its measurement varies with method. Furthermore, free association probabilities predict extralist cued recall better than do ratings and co-occurrence statistics. The measure that most closely matches the criterion task may provide the best estimate of the identity of preexisting strength.

Comprehension↗
PubMed1988

[Probability of the occurrence of radiation complications in tissues as a function of the probability of the death of their constituent cells].

The author considers some theoretical aspects of the problem of development of mathematical models to describe probabilities of the absence of radiation complications in tissues as function of the probability of a cell to survive. Since the number of tissue cells in great, a mathematical model based on an assumption of the existence of the maximum number of cells associated with development of radiation complication, leads to a sharp change in dependence of probability of radiation complications in tissues as dose function, which becomes steadier and more adequate to actual functions if one assumes the existence of reparable and irreparable spacious structures which form cells survived after irradiation and characterize cell tissue organization.

Cell Survival↗
PubMed2003

A method to combine non-probability sample data with probability sample data in estimating spatial means of environmental variables.

In estimating spatial means of environmental variables of a region from data collected by convenience or purposive sampling, validity of the results can be ensured by collecting additional data through probability sampling. The precision of the pi estimator that uses the probability sample can be increased by interpolating the values at the nonprobability sample points to the probability sample points, and using these interpolated values as an auxiliary variable in the difference or regression estimator. These estimators are (approximately) unbiased, even when the nonprobability sample is severely biased such as in preferential samples. The gain in precision compared to the pi estimator in combination with Simple Random Sampling is controlled by the correlation between the target variable and interpolated variable. This correlation is determined by the size (density) and spatial coverage of the nonprobability sample, and the spatial continuity of the target variable. In a case study the average ratio of the variances of the simple regression estimator and pi estimator was 0.68 for preferential samples of size 150 with moderate spatial clustering, and 0.80 for preferential samples of similar size with strong spatial clustering. In the latter case the simple regression estimator was substantially more precise than the simple difference estimator.

Data Collection↗
PubMed1966

Probability of response and probability of reinforcement in a response-defined analogue of an interval schedule.

Variable interval (VI) responding was hypothesized to be a function of differential reinforcement susceptibilities of various unspecified behavior chains that mediate interresponse times (IRTs). To test this hypothesis, probabilities of reinforcement were regulated for the lengths of chains of key pecking responses of pigeons, analogous to the way that VI regulates probabilities of reinforcement for IRTs. This procedure generated a number of VI-like effects, supporting the notion that VI behavior can be construed as a special case of an interaction between the organism's function relating reinforcement susceptibilities to chain length and the experimenter's function relating probabilities of reinforcement to chain length.

Animals↗
PubMed1990

Analysis of the probability distribution of small random samples by nonlinear fitting of integrated probabilities.

Small random samples of biochemical and biological data are often representative of complex distribution functions and are difficult to analyze in detail by conventional means. The common approaches reduce the data to a few representative parameters (such as their moments) or combine the data into a histogram plot. Both approaches reduce the information content of the data. By fitting the empirical cumulative distribution function itself with models of integrated probability distributions, the information content of the raw data can be fully utilized. This approach, distribution analysis by nonlinear fitting of integrated probabilities, allows analysis of normally distributed samples, truncated data sets, and multimodal distributions with a single, powerful data processing procedure.

Data Interpretation, Statistical↗
PubMed2004

Impact of candidate sire number and sire relatedness on DNA polymorphism-based measures of exclusion probability and probability of unambiguous parentage.

Genetic paternity testing can provide sire identity data for offspring when females have been exposed to multiple males. However, correct paternity assignment can be influenced by factors determined in the laboratory and by size and genetic composition of breeding groups. In the present study, DNA samples from 26 commingled beef bulls and their calves from the Nebraska Reference Herd-1 (NRH1), along with previously reported Illinois Reference/Resource Families data, were used to estimate the impact of sire number and sire relatedness on microsatellite-based paternity testing. Assay performance was measured by exclusion probabilities and probabilities of unambiguous parentage (PUP) were derived. Proportion of calves with unambiguous parentage (PCUP) was also calculated to provide a readily understandable whole-herd measure of unambiguous paternity assignment. For NRH1, theoretical and observed PCUP values were in close agreement (85.3 and 85.8%, respectively) indicating good predictive value. While the qualitative effects on PUP values of altering sire number and sire relatedness were generally predictable, we demonstrate that the impacts of these variables, and their interaction effects, can be large, are non-linear, and are quantitatively distinct for different combinations of sire number and degree of sire relatedness. In view of the potentially complex dynamics and practical consequences of these relationships in both research and animal production settings, we suggest that a priori estimation of the quantitative impact of a given set of interacting breeding group-specific and assay-specific parameters on PUP may be indicated, particularly when candidate sire pools are large, sire relatedness may be high, and/or loci numbers or heterozygosity values may be limiting.

Animals↗
PubMed1984

Interpretation of laboratory tests using a programmable hand-held calculator: calculation of posterior probability and relative risk on the basis of prior probability and sensitivity, specificity and result of the test.

A program is presented for the Hewlett-Packard HP- 41C programmable hand-held calculator that calculates the posterior probability and relative risk of an event (e.g. a disease) on the basis of prior probability (prevalence) and sensitivity, specificity and result of the test.

Bayes Theorem↗
PubMed2004

Quantum study of the N+N(2) exchange reaction: state-to-state reaction probabilities, initial state selected probabilities, Feshbach resonances, and product distributions.

We report a detailed three-dimensional time-dependent quantum dynamics study of the state-to-state N+N(2) exchange scattering in the 2.1-3.2 eV range using a recently developed ab initio potential energy surface (PES). The reactive flux arrives at the dividing surface in the asymptotic product region in a series of six packets, instead of a single packet. Further study shows that these features arise from the "Lake Eyring" region of the PES, a region with a shallow well between two transition states. Trappings due to Feshbach resonances are found to be the major cause of the time delay. A detailed analysis of the Feshbach resonance features is carried out using an L(2) calculation of the metastable states in the "Lake Eyring" region. Strong resonance features are found in the state-to-state and initial state selected reaction probabilities. The metastable states with bending motions and/or bending coupled with stretching motions are found to be the predominant source of the resonance structure. Initial state selected reaction probabilities further indicate that the lifetimes of the metastable states with bending motions in the "Lake Eyring" region are longer than those of states with stretching motions and thus dominate the reactive resonances. Resonance structures are also visible in some of the integral cross sections and should provide a means for future experimental observation of the resonance behavior. A study of the final rotational distributions shows that, for the energy range studied here, the final products are distributed toward high-rotational states. Final vibrational distributions at the temperatures 2000 and 10,000 K are also reported.

Journal Article↗
PubMed1999

The probability distribution function of structure factors with non-integral indices. III. The joint probability distribution in the P1; case.

The joint probability distribution function method has been developed in P1; for reflections with rational indices. The positional atomic parameters are considered to be the primitive random variables, uniformly distributed in the interval (0, 1), while the reflection indices are kept fixed. Owing to the rationality of the indices, distributions like P(F(p1), F(p2)) are found to be useful for phasing purposes, where p1 and p2 are any pair of vectorial indices. A variety of conditional distributions like P(|F(p1)| | |F(p2)|), P(|F(p1)| |F(p2)), P(varphi(p1)| |F(p1)|, F(p2)) are derived, which are able to estimate the modulus and phase of F(p1) given the modulus and/or phase of F(p2). The method has been generalized to handle the joint probability distribution of any set of structure factors, i.e. the distributions P(F(1), F(2),ellipsis, F(n+1)), P(|F(1)| |F(2),ellipsis, F(n+1)) and P(varphi(1)| |F|(1), F(2),ellipsis, F(n+1)) have been obtained. Some practical tests prove the efficiency of the method.

Journal Article↗
PubMed2006

[Vagueness and the directionality of verbal probability expressions: the properties of probability information and their effects on decision making].

We examined the relationship between two properties of verbal probability (VP) expressions, "vagueness" and "directionality", and investigated the effects of these properties on decision making. Vagueness is defined as its imprecise characteristic of uncertainty expressions in VP, whereas the directionality is communicative functions which cause one to focus on the occurrence or non-occurrence of the target event described by VP. Experiment 1 contrasted a disagreement in the literature as to whether one can predict the directionality from vagueness properties, and our analyses resolved the conflict by showing the ineffectiveness of the vagueness in predicting the directionality. Experiment 2 administered decision tasks involving VP and numerical translation tasks of VP. We discovered that the directionality affects only on decision tasks. The results of Experiments 1 and 2 indicated that the directionality is distinct characteristic from the vagueness of VP, and these properties affect decisions independently. Implications are discussed.

Adult↗
PubMed1989

[The role of migration in assessing age-specific event probabilities exemplified by the probability of death].

Estimating probabilities of age-specific events both in demography and in epidemiology (force of mortality, force of morbidity) will contain additional errors if the frequency of the respective events is influenced by net migration and if migration is not taken into consideration when estimating these events. The terms used in including migration into estimating the respective rates are refined terms. The influence of migration on age-specific events is demonstrated by age-specific mortality and the life expectancy computed on the basis of age-specific mortality rates for the GDR in 1984. The results demonstrate that the life expectancy of the population of Berlin will be underestimated by 0.28 years if migration processes are not taken into consideration.

Berlin↗
PubMed2006

Comparison of most probable number-PCR and most probable number-foci detection method for quantifying infectious Cryptosporidium parvum oocysts in environmental samples.

Microbial contamination of public water supplies is of significant concern, as numerous outbreaks, including Cryptosporidium, have been reported worldwide. Detection and enumeration of Cryptosporidium parvum oocysts in water supplies is important for the prevention of future cryptosporidiosis outbreaks. In addition to not identifying the oocyst species, the U.S. EPA Method 1622 does not provide information on oocyst viability or infectivity. As such, current detection strategies have been coupled with in vitro culture methods to assess oocyst infectivity. In this study, a most probable number (MPN) method was coupled with PCR (MPN-PCR) to quantify the number of infectious oocysts recovered from seeded raw water concentrates. The frequency of positive MPN-PCR results decreased as the oocyst numbers decreased. Similar results were observed when MPN was coupled to the foci detection method (MPN-FDM), which was done for comparison. For both methods, infectious oocysts were not detected below 10(3) seeded oocysts and the MPN-PCR and MPN-FDM estimates for each seed dose were generally within one-log unit of directly enumerated foci of infection. MPN-PCR estimates were 0.25, 0.54, 0 and 0.66 log(10) units higher than MPN-FDM estimates for the positive control, 10(5), 10(4) and 10(3) seed doses, respectively. The results show the MPN-PCR was the better method for the detection of infectious C. parvum oocysts in environmental water samples.

Animals↗
PubMed2002

Complex probabilities on R(N) as real probabilities on C(N) and an application to path integrals.

We establish a necessary and sufficient condition for averages over complex-valued weight functions on R(N) to be represented as statistical averages over real, non-negative probability weights on C(N). Using this result, we show that many path integrals for time-ordered expectation values of bosonic degrees of freedom in real-valued time can be expressed as statistical averages over ensembles of paths with complex-valued coordinates, and then speculate on possible consequences of this result for the relation between quantum and classical mechanics.

Journal Article↗