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PubMed2003

The meaning(s) of conditionals: conditional probabilities, mental models, and personal utilities.

Five experiments were conducted to test the hypothesis that people understand conditional statements ("if p then q") as indicating a high conditional probability P(q/p). Participants estimated the probability that a given conditional is true (Experiments 1A, 1B, and 3) or judged whether a conditional was true or false (Experiments 2 and 4) given information about the frequencies of the relevant truth table cases. Judgments were strongly influenced by the ratio of pq to p not q cases, supporting the conditional probability account In Experiments 1A, 1B, and 3, judgments were also affected by the frequency of pq cases, consistent with a version of mental model theory. Experiments 3 and 4 extended the results to thematic conditionals and showed that the pragmatic utility associated with believing a statement also affected the degree of belief in conditionals but not in logically equivalent quantified statements.

Adolescent↗

PubMed2002

Probability of prostate cancer at various levels of per cent free prostate specific antigen in Japanese men with total PSA of 4.1-10.0 ng/ml.

Estimates for the likelihood of prostate cancer at different levels of per cent free prostate specific antigen (PSA) were derived from experience with consecutive Japanese male patients with intermediate total PSA values who underwent ultrasound-guided biopsies and/or transurethral resection of the prostate. Receiver operating characteristic (ROC) curve analysis showed that in patients with a total PSA of 4.1-10.0 ng/ml, per cent free PSA identified those with prostate cancer better than did total PSA; per cent free PSA also proved superior in the subgroup whose glands appeared benign on palpation. The probabilities of prostate cancer at per cent free PSA values of 10-15, >15-20, >20-26 and >26% were 58.3, 40.8, 25.3, 14.3 and 7.6%, respectively, when analyzed without regard to findings on palpation. In patients with palpably benign glands, the corresponding values were 55.3, 35.4, 19.6, 9.7, and 4.6%, respectively. These probabilities are lower than those reported in Western countries, probably reflecting both different patterns of practice and racial differences. Race-specific assessment is recommended before applying a clinical test.

Aged↗

PubMed1997

Probability for detecting hot particles in environmental samples by sample splitting.

The presence of radioactive hot particles in environmental samples (e.g., soil, vegetation, sediments) is frequently detected by observing significant differences in the activities of sub-samples, which are otherwise alike. The probabilities for detecting hot particles in this way were calculated by using Monte Carlo methods as a function of the number of hot particles in the original sample, the number of sub-samples used, the frequency distribution of the activities of the hot particles, and the precision with which the activities of the sub-samples are determined. Assuming, for example, (i) a log-normal distribution of the activities of the hot particles with a relative standard deviation eta > or = 1, and (ii) that a difference of > 30% between the activities of the sub-sample with the largest and that with the smallest activity can be detected, splitting the original sample into three sub-samples will be sufficient to detect the presence of up to five hot particles with a probability of > 95%. If four sub-samples are used, the presence of up to 20 hot particles can be detected with this probability. In general, it will not be effective to increase the precision of the activity measurements of the sub-samples at the expense of the number of sub-samples investigated.

Environmental Pollution↗

PubMed1978

Comprehension strategies in two and three year olds: animate agents or probable events?

Preschoolers may prefer themselves, the handier toy, the smaller toy, the more probable toy, the animate noun, or the first-mentioned noun as agent in interpreting semantically reversible sentences prior to adult performance. This study asked whether individual children consistently showed preferences and, if so, which preference. Twenty-five children, aged two years, two years and six months, or three years and six months, acted out 36 semantically reversible sentences containing one animate and one inanimate noun with toys. Three separate presentations were made of each of 12 sentences, with relative toy size varying on each. The 12 sentences, which varied in presumed probability of the animate noun as agent, consisted of six simple sentences (for example, The kitty pushes the door) and their reversals (for example, The door pushes the kitty). Two and two and a half year olds showed consistent individual preferences for animate nouns as agents in some sentences but not others. Thus there was evidence only for a sentence-specific probable event strategy rather than a generally applied animate agent strategy. Some two-and-a-half-year-old children also showed consistent position preferences or word order strategies. Children did not confine themselves to a single strategy. Three and a half year olds consistently used a word order strategy. Relative object size was not a significant factor. Age and short-term memory span were more closely related than mean length of utterance to comprehension.

Age Factors↗

PubMed2003

Probabilities of alcohol high-risk drinking, abuse or dependence estimated on grounds of tobacco smoking and nicotine dependence.

AIMS: To estimate probabilities of alcohol high-risk drinking, alcohol abuse and alcohol dependence on grounds of smoking-behaviour related variables and single nicotine dependence criteria. DESIGN: Cross-sectional population-based study. SETTING: Adult population of a region in north Germany. PARTICIPANTS: Cigarette smokers (n = 2437) among a random sample of 4075 females and males aged 18-64, drawn in 1996. MEASUREMENT: Smoking, nicotine dependence according to the Diagnostic and Statistical Manual of Psychiatric Disorders (DSM-IV) and the Fagerström Test for Nicotine Dependence (FTND); increasing alcohol-related harm (ARH): high-risk drinking, DSM-IV alcohol abuse, remitted and current alcohol dependence diagnosed by the Composite International Diagnostic Interview (CIDI). FINDINGS: Having smoked 30 cigarettes or more per day, onset of smoking at the age of 17 or younger, nicotine dependence and single nicotine dependence criteria revealed odds ratios higher than 4.0 for alcohol dependence. For alcohol dependence, a logistic regression model showed an increased odds ratios for male gender, smoking for 25 years or more, no attempt to quit or cut down, continuation of smoking despite problems, craving for nicotine, withdrawal experience 1 day or longer, smoking first cigarette in the morning 5 minutes or less after waking. The probability of increasing ARH was more likely in males, smokers for 25 years or more, no attempt to quit or cut down, continuation of smoking despite problems and smoking first cigarette in the morning 5 minutes or less after waking. CONCLUSIONS: Gender and single nicotine dependence criteria show particularly high probabilities of alcohol dependence and increasing ARH. Interventions need to take these connections into account.

Adolescent↗

PubMed2004

Power of exclusion for parentage verification and probability of match for identity in American Kennel Club breeds using 17 canine microsatellite markers.

DNA analysis of microsatellite markers has become a common tool for verifying parentage in breed registries and identifying individual animals that are linked to a database or owner. Panels of markers have been developed in canines, but their utility across and within a wide range of breeds has not been reported. The American Kennel Club (AKC) authorized a study to determine the power to exclude non-parents and identify individuals using DNA genotypes of 17 microsatellite markers in two panels. Cheek swab samples were voluntarily collected at Parent Breed Club National Specialty dog shows and 9561 samples representing 108 breeds were collected, averaging 88.5 dogs per breed. The primary panel of 10 markers exceeded 99% power of exclusion for canine parentage verification of 61% of the breeds. In combination with the secondary panel of seven markers, 100% of the tested breeds exceeded 99% power of exclusion. The minimum probability match rate of the first panel was 3.6 x 10(-5) averaged across breeds, and with the addition of the second panel, the probability match rate was 3.2 x 10(-8); thus the probability of another random, unrelated dog with the same genotype is very low. The results of this analysis indicated that, on average, the primary panel meets the AKC's needs for routine parentage testing, but that a combination of 10-15 genetic markers from the two panels could yield a universal canine panel with enhanced processing efficiency, reliability and informativeness.

Animals↗

PubMed1999

Peripheral markers of oxidative stress in probable Alzheimer patients.

BACKGROUND: The current research on Alzheimer's disease is mainly focused in the post-mortem characterization of pathological and biochemical alterations in the brain. The finding of peripheral markers that could be associated with the changes observed in the Alzheimer's brain would be of interest in this field. The aim of the present study was to evaluate the state of different peripheral markers of oxidative stress in probable Alzheimer patients and compare them with a group of healthy individuals. DESIGN: The determinations made include the plasma total antioxidant capacity (TRAP) and tert-butyl hydroperoxide-initiated chemiluminescence and catalase activity in erythrocytes from 18 patients with probable Alzheimer's disease and 18 matched control subjects with normal cognitive function. RESULTS: TRAP was decreased in Alzheimer patients by 24% (control group 308 micromol L-1 Trolox, SEM 34, n = 18). tert-Butyl hydroperoxide-initiated chemiluminescence and catalase activity showed an increase in erythrocytes from Alzheimer patients by 52% (control group 116 700 cps mg-1 haemoglobin, SEM 6690) and 75% (control group 2.55 pmol mg-1 protein, SEM 0.39, n = 18) respectively. CONCLUSION: Oxidative stress in the blood of probable Alzheimer patients could be a reflection of the brain condition and suggests that oxygen free radicals could be partially responsible of the damage observed in this disease.

Aged↗

PubMed2003

Short-term subjective efficacy of doxazosin in predicting probability of prostatectomy in the management of benign prostatic hyperplasia in patients with severe symptoms.

BACKGROUND: The severity of symptoms still constitutes the major indication for transurethral prostatectomy, despite the extensive utilization of medical treatments. The aim of the study presented here was to investigate the impact of doxazosin on symptoms in relation to the probability of consequent surgery in severely symptomatic patients. METHODS: Patients with an International Prostate Symptom Score (IPSS) between 18 and 35 were included in the study. The patients received 4 mg/day doxazosin, and subjective efficacy was assessed by IPSS at the first and third months. In addition, the patients were classified at the third month according to a single question regarding satisfaction with medical treatment in terms of symptom relief as 'ineffective, no change, and effective'. RESULTS: A total of 178 patients constituted the study group. Mean total symptom scores were 24, 19 and 17 at baseline, first and third months, respectively (P < 0.05). According to results of the questionnaire, 23% of the patients claimed the treatment was ineffective, and subsequently, the majority of this group (93%) underwent prostatectomy in a year. In addition, 33% of the patients reported no change in their symptoms, while 44% reported that the medication was effective. However, after 1 year, 59% and 15% of these cases underwent surgical treatment, respectively. The probability of surgery in the 'ineffective' group was significantly higher compared to the remaining groups (P < 0.05). CONCLUSION: The majority of patients with severe symptoms who were not satisfied with the medication at the 3rd month underwent surgery. This observation may provide a predictor for subsequent probability of prostatectomy. Therefore, reassessment of patients would be a cost-effective approach for the treatment of BPH in severely symptomatic patients.

Adrenergic alpha-Antagonists↗

PubMed2003

Use of computed tomography pulmonary angiography in the diagnosis of pulmonary embolismin patients with an intermediate probability ventilation/perfusion scan.

BACKGROUND: Computed tomography pulmonary -angiography (CTPA) plays an increasingly important role in the diagnosis of pulmonary embolism (PE). Although accurate in the detection of large PE, its accuracy in other patient groups is yet to be defined. AIM: To compare CTPA with pulmonary angiography as a second-line investigation in patients with a ventilation/perfusion (VQ) scan indicating an intermediate probability of PE. METHODS: We recruited 25 patients over a 17-month period. Subjects were eligible if they: (i). had clinically suspected PE, (ii). had a VQ scan indicating an intermediate probability of PE and (iii). were referred for pulmonary angiography. Subjects underwent CTPA within 36 h of the VQ scan. CTPA was interpreted without knowledge of the results of the pulmonary angiogram by two of the authors. RESULTS: PE was prevalent (i.e. embolus detected at pulmonary angiography) in seven of 25 subjects (28%). The sensitivity of CTPA was 57% and the specificity was 94%. CONCLUSIONS: In the setting of intermediate-probability VQ scanning, CTPA may be used to clarify the diagnosis of PE. However, a negative CTPA cannot -definitely exclude PE. Conventional pulmonary angiography may be necessary to determine the presence of PE if CTPA is negative.

Adult↗

PubMed2004

[Ultrasound follow-up of palpable solid, probably benign breast lesions (BI-RADS category III)].

PURPOSE: To determine whether palpable non-calcified solid breast masses with benign morphology on ultrasound can be classified as probably benign and whether these lesions fulfill the criteria required for BI-RADS (TM) category III. MATERIALS AND METHODS: This analysis includes 78 patients with 80 palpable non-calcified solid masses that were classified as probably benign at initial sonography. Of 78 patients, 66 had periodic imaging surveillance (2 - 8 years, mean 4.6 years). The remaining 12 patients had a biopsy after initial imaging. RESULTS: In the 64 patients under surveillance, palpable lesions remained stable at follow-up. In 2 patients lesions increased in size during follow-up and no malignancy was diagnosed at subsequent open biopsy. In 19 of the 66 patients, 29 additional nonpalpable lesions of similar morphology were detected on ultrasound. No malignancy was diagnosed in the 12 patients, who had a biopsy after initial imaging. CONCLUSION: Our data suggest that palpable non-calcified solid breast masses with benign morphology on ultrasound can be classified as probably benign (BI-RADS (TM) category III). Biopsy can be averted when lesions remain stable at follow-up.

Adolescent↗

PubMed2005

The role of qualitative D-dimer assays, clinical probability, and noninvasive imaging tests for the diagnosis of deep vein thrombosis and pulmonary embolism.

Recent advances in the management of patients with suspected venous thromboembolism have both improved diagnostic accuracy as well as made management algorithms safer and more accessible. It is now clear that determination of clinical probability prior to diagnostic testing will improve patient management. D-dimer testing can be employed to decrease the need for imaging tests. Patients at low risk with a negative qualitative D-dimer can avoid imaging tests. Imaging test interpretation benefits from consideration of pretest probability also as this helps clinicians determine when a test may be falsely negative or falsely positive. Diagnostic strategies should include pretest clinical probability, D-dimer assays, and noninvasive imaging tests.

Algorithms↗

PubMed1995

Logarithmic correction to the probability of capture for dissipatively perturbed Hamiltonian systems.

Hamiltonian systems are analyzed with a double homoclinic orbit connecting a saddle to itself. Competing centers exist. A small dissipative perturbation causes the stable and unstable manifolds of the saddle point to break apart. The stable manifolds of the saddle point are the boundaries of the basin of attraction for the competing attractors. With small dissipation, the boundaries of the basins of attraction are known to be tightly wound and spiral-like. Small changes in the initial condition can alter the equilibrium to which the solution is attracted. Near the unperturbed homoclinic orbit, the boundary of the basin of attraction consists of a large sequence of nearly homoclinic orbits surrounded by close approaches to the saddle point. The slow passage through an unperturbed homoclinic orbit (separatrix) is determined by the change in the value of the Hamiltonian from one saddle approach to the next. The probability of capture can be asymptotically approximated using this change in the Hamiltonian. The well-known leading-order change of the Hamiltonian from one saddle approach to the next is due to the effect of the perturbation on the homoclinic orbit. A logarithmic correction to this change of the Hamiltonian is shown to be due to the effect of the perturbation on the saddle point itself. It is shown that the probability of capture can be significantly altered from the well-known leading-order probability for Hamiltonian systems with double homoclinic orbits of the twisted type, an example of which is the Hamiltonian system corresponding to primary resonance. Numerical integration of the perturbed Hamiltonian system is used to verify the accuracy of the analytic formulas for the change in the Hamiltonian from one saddle approach to the next. (c) 1995 American Institute of Physics.

Journal Article↗

PubMed2005

A theoretical study of molecular conduction. II. A Hartree-Fock approach to transmission probability.

In this paper, we discuss molecular conductivity based on Green's function methods. In our calculations, we adopted the self-energy formalism to accommodate semi-infinite electrodes connected to a molecule, and the self-energy was obtained from the surface Green's function of the electrodes. We adopted the formalism of the surface Green's function derived by Sanvito et al. [Phys. Rev. B 59, 11936 (1999)] and Krstic et al. [Phys. Rev. B 66, 205319 (2002)], and although their formalisms for the surface Green's function were different, we were able to demonstrate that these formalisms are mathematically identical. We analyzed the electron transmission probability by using the spectrum expression of Green's function, instead of using the inverse matrix of the effective Hamiltonian that includes an isolated molecule and the electrodes. Finally, we calculated the transmission probability of benzenedithiol based on the Hartree-Fock method and analyzed the disappearance of the transmission probability due to the orbital interference.

Journal Article↗

PubMed2001

Incidence of sensitization, symptoms, and probable occupational rhinoconjunctivitis and asthma in apprentices starting exposure to latex.

Latex is a well-known sensitizer. Prospective studies in apprentices beginning to be exposed to latex have not been carried out. We wanted to determine the incidence of skin reactivity, cutaneous symptoms, rhinoconjunctivitis (RC) symptoms, respiratory symptoms, probable occupational RC, and asthma in apprentices in dental hygiene. A total of 122 students starting a program in dental hygiene technology were recruited between 1993 and 1995. A questionnaire, skin-prick tests with common aeroallergens and latex, and assessment of spirometry and responsiveness to methacholine were carried out on entry and at follow-up visits at 20 and 32 months after the start of exposure. Of the 110 subjects who participated for at least 1 follow-up visit, skin reactivity to latex developed in 7. Cutaneous symptoms developed in 6 of the 7, RC symptoms developed in 2, and respiratory symptoms developed in 1. Five of the 7 subjects had significant changes in methacholine responsiveness and fulfilled the definition of probable occupational asthma. Sensitized subjects were more likely to be atopic and to have a previous history of asthma and respiratory symptoms on exercise than were nonsensitized subjects. Three subjects at the 20-month assessment and 4 subjects at the 32-month visit showed skin reactivity. The cumulative incidences for skin sensitization, probable occupational RC, and occupational asthma to latex were 6.4%, 1.8%, and 4.5%, respectively.

Adolescent↗

PubMed2002

Lévy processes in free probability.

This is the continuation of a previous article that studied the relationship between the classes of infinitely divisible probability measures in classical and free probability, respectively, via the Bercovici-Pata bijection. Drawing on the results of the preceding article, the present paper outlines recent developments in the theory of Lévy processes in free probability.

Journal Article↗

PubMed1969

Probability distributions related to the law of the iterated logarithm.

Let W(t) denote a standard Wiener process for 0 </= t < infinity. We compute the probability that W(t) >/= t((1/2))A(t) for some t >/= 1 (or for some t >/= 0) for a certain class of functions A(t), including functions which are approximately (2 log log t)((1/2)) as t --> infinity. We also give an invariance principle which states that this probability is the limit as m --> infinity of the probability that s(n) >/= n((1/2))A(n/m) for some n >/= m (or for some n >/= 1), where s(n) is the sum of n independent and identically distributed random variables with mean 0 and variance 1.

Journal Article↗

PubMed1979

Triplet phase invariants: Formula for centric case from fourth-order determinantal joint probability distributions.

A formula is derived for centrosymmetric crystals from fourth-order determinantal joint probability distributions that provides, for the triplet invariants, values of P(+)/P(-), the ratio of the probability that an invariant has a plus sign associated with it to the probability that it has a minus sign. The formula makes use of the entire data set in the computations for each invariant. Test calculations indicate that many hundreds of invariants can be selected by use of the formula with essential certainty that their value is equal to zero. Several invariants whose value is equal to pi can also be selected on occasion with very high reliability.

Journal Article↗

PubMed1981

Selecting the highest probability in binomial or multinomial trials.

Some sequential procedures are considered for selecting the binomial population with largest success probability or for selecting the multinomial outcome with highest cell probability. Procedures with and without sequential elimination of inferior populations are evaluated with respect to the expected probability of the population selected.

Journal Article↗