Quantifying the risks and benefits of efavirenz use in HIV-infected women of childbearing age in the USA.

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Hsu, H E; Rydzak, C E; Cotich, K L; Wang, B; Sax, P E; Losina, E; Freedberg, K A; Goldie, S J; Lu, Z; Walensky, R P

2011-02-01

The aim of the study was to quantify the benefits (life expectancy gains) and risks (efavirenz-related teratogenicity) associated with using efavirenz in HIV-infected women of childbearing age in the USA. We used data from the Women's Interagency HIV Study in an HIV disease simulation model to estimate life expectancy in women who receive an efavirenz-based initial antiretroviral regimen compared with those who delay efavirenz use and receive a boosted protease inhibitor-based initial regimen. To estimate excess risk of teratogenic events with and without efavirenz exposure per 100,000 women, we incorporated literature-based rates of pregnancy, live births, and teratogenic events into a decision analytic model. We assumed a teratogenicity risk of 2.90 events/100 live births in women exposed to efavirenz during pregnancy and 2.68/100 live births in unexposed women. Survival for HIV-infected women who received an efavirenz-based initial antiretroviral therapy (ART) regimen was 0.89 years greater than for women receiving non-efavirenz-based initial therapy (28.91 vs. 28.02 years). The rate of teratogenic events was 77.26/100,000 exposed women, compared with 72.46/100,000 unexposed women. Survival estimates were sensitive to variations in treatment efficacy and AIDS-related mortality. Estimates of excess teratogenic events were most sensitive to pregnancy rates and number of teratogenic events/100 live births in efavirenz-exposed women. Use of non-efavirenz-based initial ART in HIV-infected women of childbearing age may reduce life expectancy gains from antiretroviral treatment, but may also prevent teratogenic events. Decision-making regarding efavirenz use presents a trade-off between these two risks; this study can inform discussions between patients and health care providers.

Quantifying the risks and benefits of efavirenz use in HIV-infected women of childbearing age in the United States

Science.gov (United States)

Hsu, HE; Rydzak, CE; Cotich, KL; Wang, B; Sax, PE; Losina, E; Freedberg, KA; Goldie, SJ; Lu, Z; Walensky, RP

2010-01-01

Objectives We quantified the benefits (life expectancy gains) and harms (efavirenz-related teratogenicity) associated with using efavirenz in HIV-infected women of childbearing age in the United States. Methods We used data from the Women’s Interagency HIV Study in an HIV disease simulation model to estimate life expectancy in women who receive an efavirenz-based initial antiretroviral regimen compared with those who delay efavirenz use and receive a boosted protease inhibitor-based initial regimen. To estimate excess risk of teratogenic events with and without efavirenz exposure per 100,000 women, we incorporated literature-based rates of pregnancy, live births, and teratogenic events into a decision analytic model. We assumed a teratogenicity risk of 2.90 events/100 live births in women exposed to efavirenz during pregnancy and 2.68/100 live births in unexposed women. Results Survival for HIV-infected women who received an efavirenz-based initial antiretroviral therapy regimen was 0.89 years greater than for women receiving non-efavirenz-based initial therapy (28.91 vs. 28.02 years). The rate of teratogenic events was 77.26/100,000 exposed women, compared with 72.46/100,000 unexposed women. Survival estimates were sensitive to variations in treatment efficacy and AIDS-related mortality. Estimates of excess teratogenic events were most sensitive to pregnancy rates and number of teratogenic events/100 live births in efavirenz-exposed women. Conclusions Use of non-efavirenz-based initial antiretroviral therapy in HIV-infected women of childbearing age may reduce life expectancy gains from antiretroviral treatment, but may also prevent teratogenic events. Decision-making regarding efavirenz use presents a tradeoff between these two risks; this study can inform discussions between patients and health care providers. PMID:20561082

Pharmacokinetics of efavirenz and treatment of HIV-1 among pregnant women with and without tuberculosis coinfection.

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Dooley, Kelly E; Denti, Paolo; Martinson, Neil; Cohn, Silvia; Mashabela, Fildah; Hoffmann, Jennifer; Haas, David W; Hull, Jennifer; Msandiwa, Regina; Castel, Sandra; Wiesner, Lubbe; Chaisson, Richard E; McIlleron, Helen

2015-01-15

Pregnancy and tuberculosis treatment or prophylaxis can affect efavirenz pharmacokinetics, maternal human immunodeficiency virus type 1 (HIV-1) treatment outcomes, and mother-to-child transmission (MTCT) risk. We evaluated a prospective cohort of pregnant, HIV-infected women with and without tuberculosis in Soweto, South Africa. Pharmacokinetic sampling was performed at gestation week 37 and during the postpartum period. Efavirenz trough concentrations (Cmin) were predicted using population pharmacokinetic models. HIV-viral load was measured at delivery for mothers and at 6 weeks of age for infants. Ninety-seven women participated; 44 had tuberculosis. Median efavirenz Cmin during pregnancy was 1.35 µg/mL (interquartile range [IQR], 0.90-2.07 µg/mL; 27% had an efavirenz Cmin of pregnant women with extensive CYP2B6 genotypes had an efavirenz Cmin of HIV-viral load at delivery was more common among pregnant women with tuberculosis, in whom ART was generally initiated later. © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Efavirenz Has the Highest Anti-Proliferative Effect of Non-Nucleoside Reverse Transcriptase Inhibitors against Pancreatic Cancer Cells.

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Markus Hecht

Full Text Available Cancer prevention and therapy in HIV-1-infected patients will play an important role in future. The non-nucleoside reverse transcriptase inhibitors (NNRTI Efavirenz and Nevirapine are cytotoxic against cancer cells in vitro. As other NNRTIs have not been studied so far, all clinically used NNRTIs were tested and the in vitro toxic concentrations were compared to drug levels in patients to predict possible anti-cancer effects in vivo.Cytotoxicity was studied by Annexin-V-APC/7AAD staining and flow cytometry in the pancreatic cancer cell lines BxPC-3 and Panc-1 and confirmed by colony formation assays. The 50% effective cytotoxic concentrations (EC50 were calculated and compared to the blood levels in our patients and published data.The in vitro EC50 of the different drugs in the BxPC-3 pancreatic cancer cells were: Efavirenz 31.5 μmol/l (= 9944 ng/ml, Nevirapine 239 μmol/l (= 63,786 ng/ml, Etravirine 89.0 μmol/l (= 38,740 ng/ml, Lersivirine 543 μmol/l (= 168,523 ng/ml, Delavirdine 171 μmol/l (= 78,072 ng/ml, Rilpivirine 24.4 μmol/l (= 8941 ng/ml. As Efavirenz and Rilpivirine had the highest cytotoxic potential and Nevirapine is frequently used in HIV-1 positive patients, the results of these three drugs were further studied in Panc-1 pancreatic cancer cells and confirmed with colony formation assays. 205 patient blood levels of Efavirenz, 127 of Rilpivirine and 31 of Nevirapine were analyzed. The mean blood level of Efavirenz was 3587 ng/ml (range 162-15,363 ng/ml, of Rilpivirine 144 ng/ml (range 0-572 ng/ml and of Nevirapine 4955 ng/ml (range 1856-8697 ng/ml. Blood levels from our patients and from published data had comparable Efavirenz levels to the in vitro toxic EC50 in about 1 to 5% of all patients.All studied NNRTIs were toxic against cancer cells. A low percentage of patients taking Efavirenz reached in vitro cytotoxic blood levels. It can be speculated that in HIV-1 positive patients having high Efavirenz blood levels pancreatic

Acute Liver Failure among Patients on Efavirenz-Based Antiretroviral Therapy

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Innocent Lule Segamwenge

2018-01-01

Full Text Available Objectives. To describe the clinical characteristics of patients presenting with fulminant liver failure after varying periods of exposure to Efavirenz containing antiretroviral medications. Methods. We report a series of 4 patients with human immunodeficiency virus (HIV infection who were admitted with acute liver failure (ALF over a 6-month period. All these patients had been treated with a range of Efavirenz containing antiretroviral regimens and were negative for hepatitis A, B, and C infections as well as other opportunistic infections, all were negative for autoimmune hepatitis, and none had evidence of chronic liver disease or use of alcohol or herbal medications. Information on patient clinical characteristics, current antiretroviral regimen, CD4 count, HIV-1 RNA levels, and clinical chemistry parameters was collected. Informed consent was provided. Results. During a 6-month period, four patients without other known risk factors for acute hepatitis presented with symptomatic drug-induced liver injury with varying symptoms and outcomes. The pattern of liver injury was hepatocellular for all the 4 cases. Liver biopsies were done for all the four cases and the results showed a heavy mixed inflammatory cell infiltrate with eosinophils. For three patients withdrawal of Efavirenz from their antiretroviral regimen was sufficient to restore transaminase levels to normal and led to improvement of clinical symptoms. For one patient his clinical course was characterized by fulminant liver failure and fluctuating episodes of hepatic encephalopathy which ultimately resulted in his death. Conclusion. Hepatotoxicity of Efavirenz is not as rare as previously described in the literature and does actually present with fatal outcomes. The key message to note is that frequent monitoring of liver enzymes should be done at initiation of antiretroviral therapy and should continue throughout the treatment period.

Chemical interactions study of antiretroviral drugs efavirenz and lamivudine concerning the development of stable fixed-dose combination formulations for AIDS treatment

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Gomes, Elionai C. de L.; Mussel, Wagner N.; Resende, Jarbas M.; Yoshida, Maria I., E-mail: mirene@ufmg.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Instituto de Ciencias Exatas. Departamento de Quimica; Fialho, Silvia L.; Barbosa, Jamile; Fialho, Silvia L. [Fundacao Ezequiel Dias, Belo Horizonte, MG (Brazil)

2013-04-15

Lamivudine and efavirenz are among the most worldwide used drugs for acquired immune deficiency syndrome (AIDS) treatment. Solid state nuclear magnetic resonance (ssNMR), Fourier-transformed infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and thermo-optical analysis (TOA) were used to study possible interactions between these drugs, aiming the development of a fixed-dose drug combination. DSC and TOA have evidenced significant shifts on the melting points of both drugs in the mixture, which may be due to interaction between them. Although DSC and TOA results indicated incompatibility between the drugs, FTIR spectra were mostly unmodified due to overlapping peaks. The ssNMR analyses showed significant changes in chemical shifts values of the mixture when compared with spectra of pure drugs, especially in the signals relating to the deficient electron carbon atoms of both drugs. These results confirm the interactions suggested by DSC and TOA, which is probably due to acid-base interactions between electronegative and deficient electron atoms of both lamivudine and efavirenz. (author)

Chemical interactions study of antiretroviral drugs efavirenz and lamivudine concerning the development of stable fixed-dose combination formulations for AIDS treatment

International Nuclear Information System (INIS)

Gomes, Elionai C. de L.; Mussel, Wagner N.; Resende, Jarbas M.; Yoshida, Maria I.

2013-01-01

Lamivudine and efavirenz are among the most worldwide used drugs for acquired immune deficiency syndrome (AIDS) treatment. Solid state nuclear magnetic resonance (ssNMR), Fourier-transformed infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and thermo-optical analysis (TOA) were used to study possible interactions between these drugs, aiming the development of a fixed-dose drug combination. DSC and TOA have evidenced significant shifts on the melting points of both drugs in the mixture, which may be due to interaction between them. Although DSC and TOA results indicated incompatibility between the drugs, FTIR spectra were mostly unmodified due to overlapping peaks. The ssNMR analyses showed significant changes in chemical shifts values of the mixture when compared with spectra of pure drugs, especially in the signals relating to the deficient electron carbon atoms of both drugs. These results confirm the interactions suggested by DSC and TOA, which is probably due to acid-base interactions between electronegative and deficient electron atoms of both lamivudine and efavirenz. (author)

A sensitive and selective liquid chromatography/tandem mass spectrometry method for quantitative analysis of efavirenz in human plasma.

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Praveen Srivastava

Full Text Available A selective and a highly sensitive method for the determination of the non-nucleoside reverse transcriptase inhibitor (NNRTI, efavirenz, in human plasma has been developed and fully validated based on high performance liquid chromatography tandem mass spectrometry (LC-MS/MS. Sample preparation involved protein precipitation followed by one to one dilution with water. The analyte, efavirenz was separated by high performance liquid chromatography and detected with tandem mass spectrometry in negative ionization mode with multiple reaction monitoring. Efavirenz and ¹³C₆-efavirenz (Internal Standard, respectively, were detected via the following MRM transitions: m/z 314.20243.90 and m/z 320.20249.90. A gradient program was used to elute the analytes using 0.1% formic acid in water and 0.1% formic acid in acetonitrile as mobile phase solvents, at a flow-rate of 0.3 mL/min. The total run time was 5 min and the retention times for the internal standard (¹³C₆-efavirenz and efavirenz was approximately 2.6 min. The calibration curves showed linearity (coefficient of regression, r>0.99 over the concentration range of 1.0-2,500 ng/mL. The intraday precision based on the standard deviation of replicates of lower limit of quantification (LLOQ was 9.24% and for quality control (QC samples ranged from 2.41% to 6.42% and with accuracy from 112% and 100-111% for LLOQ and QC samples. The inter day precision was 12.3% and 3.03-9.18% for LLOQ and quality controls samples, and the accuracy was 108% and 95.2-108% for LLOQ and QC samples. Stability studies showed that efavirenz was stable during the expected conditions for sample preparation and storage. The lower limit of quantification for efavirenz was 1 ng/mL. The analytical method showed excellent sensitivity, precision, and accuracy. This method is robust and is being successfully applied for therapeutic drug monitoring and pharmacokinetic studies in HIV-infected patients.

Influence of the Efavirenz Micronization on Tableting and Dissolution

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Lucio Mendes Cabral

2012-09-01

Full Text Available The purpose of this study was to propose an analytical procedure that provides the effects of particle size and surface area on dissolution of efavirenz. Five different batches obtained by different micronization processes and with different particle size distribution and surface area were studied. The preformulation studies and dissolution curves were used to confirm the particle size distribution effect on drug solubility. No polymorphic variety or amorphization was observed in the tested batches and the particle size distribution was determined as directly responsible for the improvement of drug dissolution. The influence of the preparation process on the tablets derived from efavirenz was observed in the final dissolution result in which agglomeration, usually seen in non-lipophilic micronized material, was avoided through the use of an appropriate wet granulation method. For these reasons, micronization may represent one viable alternative for the formulation of brick dust drugs.

Pharmacogenetic associations with plasma efavirenz concentrations and clinical correlates in a retrospective cohort of Ghanaian HIV-infected patients.

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Sarfo, Fred S; Zhang, Yuan; Egan, Deirdre; Tetteh, Lambert A; Phillips, Richard; Bedu-Addo, George; Sarfo, Maame Anima; Khoo, Saye; Owen, Andrew; Chadwick, David R

2014-02-01

Efavirenz is widely used in first-line antiretroviral therapy in sub-Saharan Africa. However, exposure to efavirenz shows marked interindividual variability that is genetically mediated with potential for important pharmacodynamic consequences. The aims of this study were to assess the frequencies of CYP2B6, CYP2A6, UGT2B7 and CAR single nucleotide polymorphisms (SNPs) and their impact on plasma efavirenz concentration and clinical/immunological responses in Ghanaian patients. Genomic DNA from 800 HIV-infected patients was genotyped for selected SNPs by real-time PCR-based allelic discrimination. Mid-dose plasma efavirenz concentrations were measured for 521 patients using HPLC with UV detection. Clinical outcomes in 299 patients on efavirenz were retrospectively assessed. Univariate and multivariate linear regression were performed using best subset selection. Time-to-event outcomes were analysed using a Cox proportional hazards regression model. The variant allele frequencies for CYP2B6 516G>T (rs3745274), CYP2B6 983T>C (rs28399499), CYP2A6 -48T>G (CYP2B6*9B; rs28399433), UGT2B7 802C>T (UGT2B7*2; rs7439366), UGT2B7 735A>G (UGT2B7*1c; rs28365062) and CAR 540C>T (rs2307424) were 48%, 4%, 3%, 23%, 15% and 7%, respectively. CYP2B6 516G>T, CYP2B6 983T>C and CYP2A6 -48T>G were associated with significantly elevated efavirenz concentrations. A trend towards association between plasma efavirenz concentration and CAR 540C>T was observed. CYP2B6 516G homozygosity was associated with immunological failure [adjusted hazards ratio compared with T homozygosity, 1.70 (1.04-2.76); P = 0.03]. CYP2B6 and CYP2A6 SNPs were associated with higher plasma efavirenz concentrations due to reduction in major and minor phase I routes of elimination, respectively. Further prospective studies are needed to validate the pharmacodynamic correlates of these polymorphisms in this population.

Race/Ethnicity and the Pharmacogenetics of Reported Suicidality With Efavirenz Among Clinical Trials Participants.

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Mollan, Katie R; Tierney, Camlin; Hellwege, Jacklyn N; Eron, Joseph J; Hudgens, Michael G; Gulick, Roy M; Haubrich, Richard; Sax, Paul E; Campbell, Thomas B; Daar, Eric S; Robertson, Kevin R; Ventura, Diana; Ma, Qing; Edwards, Digna R Velez; Haas, David W

2017-09-01

We examined associations between suicidality and genotypes that predict plasma efavirenz exposure among AIDS Clinical Trials Group study participants in the United States. Four clinical trials randomly assigned treatment-naive participants to efavirenz-containing regimens; suicidality was defined as reported suicidal ideation or attempted or completed suicide. Genotypes that predict plasma efavirenz exposure were defined by CYP2B6 and CYP2A6 polymorphisms. Associations were evaluated with weighted Cox proportional hazards models stratified by race/ethnicity. Additional analyses adjusted for genetic ancestry and selected covariates. Among 1833 participants, suicidality was documented in 41 in exposed analyses, and 34 in on-treatment analyses. In unadjusted analyses based on 12 genotype levels, suicidality increased per level in exposed (hazard ratio, 1.11; 95% confidence interval, .96-1.27) and on-treatment 1.16; 1.01-1.34) analyses. In the on-treatment analysis, the association was strongest among white but nearly null among black participants. Considering 3 metabolizer levels (extensive, intermediate and slow), slow metabolizers were at increased risk. Results were similar after baseline covariate-adjustment for genetic ancestry, sex, age, weight, injection drug use history, and psychiatric history or recent psychoactive medication. Genotypes that predict higher plasma efavirenz exposure were associated with increased risk of suicidality. Strength of association varied by race/ethnicity. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America.

Efavirenz Dissolution Enhancement I: Co-Micronization

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Helvécio Vinícius Antunes Rocha

2012-12-01

Full Text Available AIDS constitutes one of the most serious infectious diseases, representing a major public health priority. Efavirenz (EFV, one of the most widely used drugs for this pathology, belongs to the Class II of the Biopharmaceutics Classification System for drugs with very poor water solubility. To improve EFV’s dissolution profile, changes can be made to the physical properties of the drug that do not lead to any accompanying molecular modifications. Therefore, the study objective was to develop and characterize systems with efavirenz able to improve its dissolution, which were co-processed with sodium lauryl sulfate (SLS and polyvinylpyrrolidone (PVP. The technique used was co-micronization. Three different drug:excipient ratios were tested for each of the two carriers. The drug dispersion dissolution results showed significant improvement for all the co-processed samples in comparison to non-processed material and corresponding physical mixtures. The dissolution profiles obtained for dispersion with co-micronized SLS samples proved superior to those of co-micronized PVP, with the proportion (1:0.25 proving the optimal mixture. The improvements may be explained by the hypothesis that formation of a hydrophilic layer on the surface of the micronized drug increases the wettability of the system formed, corroborated by characterization results indicating no loss of crystallinity and an absence of interaction at the molecular level.

Efficacy and Safety of Lopinavir/ritonavir- versus Efavirenz-based Antiretroviral Therapy in HIV-Infected Pregnant Ugandan Women

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COHAN, Deborah; NATUREEBA, Paul; KOSS, Catherine A.; PLENTY, Albert; LUWEDDE, Flavia; MWESIGWA, Julia; ADES, Veronica; CHARLEBOIS, Edwin D.; GANDHI, Monica; CLARK, Tamara D.; NZARUBARA, Bridget; ACHAN, Jane; RUEL, Theodore; KAMYA, Moses R.; HAVLIR, Diane V.

2015-01-01

Objective Combination antiretroviral therapy (ART) is now the global standard for HIV-infected pregnant and breastfeeding women at all CD4 cell counts. We compared the efficacy and safety of an efavirenz versus lopinavir/ritonavir regimen for HIV-infected pregnant women initiating ART in rural Uganda. Design Randomized clinical trial. Methods We performed a planned secondary analysis comparing viral load suppression (HIV-1 RNA ≤400 copies/ml), safety, and HIV transmission to infants in a trial designed to test the hypothesis that lopinavir/ritonavir- versus efavirenz-based ART would reduce placental malaria (PROMOTE, ClinicalTrials.gov, NCT00993031). HIV-infected, ART-naïve pregnant women at 12–28 weeks gestation and any CD4 cell count were randomized. ART was provided and participants were counseled to breastfeed for one year postpartum. Results The median age of the 389 study participants was 29 years; median CD4 cell count was 370 cells/mm3. At delivery, virologic suppression was 97.6% in the efavirenz arm and 86.0% in the lopinavir/ritonavir arm, p HIV (both in the lopinavir/ritonavir arm) and HIV-free infant survival was similar between study arms: 92.9% (lopinavir/ritonavir) versus 97.2% (efavirenz), p = 0.10. Conclusions Virologic suppression at delivery was higher with an efavirenz- versus lopinavir/ritonavir-based regimen. However, women in both arms achieved high levels of virologic suppression through one year postpartum and the risk of transmission to infants was low. PMID:25426808

Efficacy and safety of lopinavir/ritonavir versus efavirenz-based antiretroviral therapy in HIV-infected pregnant Ugandan women.

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Cohan, Deborah; Natureeba, Paul; Koss, Catherine A; Plenty, Albert; Luwedde, Flavia; Mwesigwa, Julia; Ades, Veronica; Charlebois, Edwin D; Gandhi, Monica; Clark, Tamara D; Nzarubara, Bridget; Achan, Jane; Ruel, Theodore; Kamya, Moses R; Havlir, Diane V

2015-01-14

Combination antiretroviral therapy (ART) is now the global standard for HIV-infected pregnant and breastfeeding women at all CD4⁺ cell counts. We compared the efficacy and safety of an efavirenz versus lopinavir/ritonavir regimen for HIV-infected pregnant women initiating ART in rural Uganda. Randomized clinical trial. We performed a planned secondary analysis comparing viral load suppression (HIV-1 RNA ≤400 copies/ml), safety, and HIV transmission to infants in a trial designed to test the hypothesis that lopinavir/ritonavir versus efavirenz-based ART would reduce placental malaria (PROMOTE, ClinicalTrials.gov, NCT00993031). HIV-infected, ART-naive pregnant women at 12-28 weeks gestation and any CD4⁺ cell count were randomized. ART was provided and participants were counseled to breastfeed for 1 year postpartum. The median age of the 389 study participants was 29 years; median CD4⁺ cell count was 370 cells/μl. At delivery, virologic suppression was 97.6% in the efavirenz arm and 86.0% in the lopinavir/ritonavir arm (P HIV (both in the lopinavir/ritonavir arm), and HIV-free infant survival was similar between study arms: 92.9% (lopinavir/ritonavir) versus 97.2% (efavirenz) (P = 0.10). Virologic suppression at delivery was higher with an efavirenz versus lopinavir/ritonavir-based regimen. However, women in both arms achieved high levels of virologic suppression through 1 year postpartum and the risk of transmission to infants was low.

Efavirenz: A review of the epidemiology, severity and management ...

African Journals Online (AJOL)

The NPSEs tend to occur within the first few days of initiation of therapy and resolve spontaneously within the first 4 - 6 weeks, with the most commonly reported being dizziness, insomnia, headache, abnormal dreams and impaired concentration. The plasma level of efavirenz and genetic polymorphisms are thought to play ...

Crystal structure determination of Efavirenz

International Nuclear Information System (INIS)

Popeneciu, Horea; Dumitru, Ristoiu; Tripon, Carmen; Borodi, Gheorghe; Pop, Mihaela Maria

2015-01-01

Needle-shaped single crystals of the title compound, C 14 H 9 ClF 3 NO 2 , were obtained from a co-crystallization experiment of Efavirenz with maleic acid in a (1:1) ratio, using methanol as solvent. Crystal structure determination at room temperature revealed a significant anisotropy of the lattice expansion compared to the previously reported low-temperature structure. In both low- and room temperature structures the cyclopropylethynyl fragment in one of the asymmetric unit molecules is disordered. While at low-temperature only one C atom exhibits positional disorder, at room temperature the disorder is present for two C atoms of the cyclopropane ring

Pharmacogenetic & pharmacokinetic biomarker for efavirenz based ARV and rifampicin based anti-TB drug induced liver injury in TB-HIV infected patients.

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Getnet Yimer

Full Text Available BACKGROUND: Implication of pharmacogenetic variations and efavirenz pharmacokinetics in concomitant efavirenz based antiviral therapy and anti-tubercular drug induced liver injury (DILI has not been yet studied. We performed a prospective case-control association study to identify the incidence, pharmacogenetic, pharmacokinetic and biochemical predictors for anti-tubercular and antiretroviral drugs induced liver injury (DILI in HIV and tuberculosis (TB co-infected patients. METHODS AND FINDINGS: Newly diagnosed treatment naïve TB-HIV co-infected patients (n = 353 were enrolled to receive efavirenz based ART and rifampicin based anti-TB therapy, and assessed clinically and biochemically for DILI up to 56 weeks. Quantification of plasma efavirenz and 8-hydroxyefaviernz levels and genotyping for NAT2, CYP2B6, CYP3A5, ABCB1, UGT2B7 and SLCO1B1 genes were done. The incidence of DILI and identification of predictors was evaluated using survival analysis and the Cox Proportional Hazards Model. The incidence of DILI was 30.0%, or 14.5 per 1000 person-week, and that of severe was 18.4%, or 7.49 per 1000 person-week. A statistically significant association of DILI with being of the female sex (p = 0.001, higher plasma efavirenz level (p = 0.009, efavirenz/8-hydroxyefavirenz ratio (p = 0.036, baseline AST (p = 0.022, ALT (p = 0.014, lower hemoglobin (p = 0.008, and serum albumin (p = 0.007, NAT2 slow-acetylator genotype (p = 0.039 and ABCB1 3435TT genotype (p = 0.001. CONCLUSION: We report high incidence of anti-tubercular and antiretroviral DILI in Ethiopian patients. Between patient variability in systemic efavirenz exposure and pharmacogenetic variations in NAT2, CYP2B6 and ABCB1 genes determines susceptibility to DILI in TB-HIV co-infected patients. Close monitoring of plasma efavirenz level and liver enzymes during early therapy and/or genotyping practice in HIV clinics is recommended for early identification

Effect of Food on the Steady-State Pharmacokinetics of Tenofovir and Emtricitabine plus Efavirenz in Ugandan Adults

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Mohammed Lamorde

2012-01-01

Full Text Available We investigated the effect of food on the steady-state pharmacokinetics of a proprietary fixed-dose combination (FDC tablet containing tenofovir disoproxil fumarate (TDF/emtricitabine/efavirenz. Fifteen Ugandan HIV-1 patients at steady-state dosing with TDF/emtricitabine/efavirenz were admitted for 24-hour intensive pharmacokinetic sampling after dosing in the fasting state. Blood sampling was repeated seven days later with TDF/emtricitabine/efavirenz administered with food (19 g fat. Drug concentrations in plasma were determined by liquid chromatography and tandem mass spectrometry. Geometric mean ratios (GMRs and confidence intervals (CIs of parameters were calculated (reference, fasting. For efavirenz, GMRs (90% CIs for Cmax, AUC0-24, and C24 were 1.47 (1.24–1.75, 1.13 (1.03–1.23, and 1.01 (0.91–1.11, respectively. Corresponding GMRs were 1.04 (0.84–1.27, 1.19 (1.10–1.29, and 0.99 (0.82–1.19 for tenofovir, 0.83 (0.76–0.92, 0.87 (0.78–0.97, and 0.91 (0.73–1.14 for emtricitabine. Stable patients may take the FDC without meal restrictions. The FDC should be taken without food by patients experiencing central nervous system toxicities.

Formulation and development of bicontinuous nanostructured liquid crystalline particles of efavirenz.

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Avachat, Amelia M; Parpani, Shreekrishna S

2015-02-01

Efavirenz is a lipophilic non-nucleoside reverse transcriptase inhibitor used in the first-line pediatric therapeutic cocktail. Due to its high lipophilicity (logP = 5.4) and poor aqueous solubility (intrinsic water solubility = 8.3 μg/mL) efavirenz has low bioavailability. A 30 mg/mL solution in a medium-chain triglyceride vehicle is the only pediatric formulation available with an oral bioavailability 20% lower than the solid form. The current work was aimed at formulating and characterizing liquid crystal nanoparticles for oral delivery of efavirenz to improve oral bioavailability, provide sustained release, minimize side effects and drug resistance. Formulation of cubosomes was done by two methods; sonication and spray drying. Sonication gave highest entrapment efficiency and least particle size. Further, monoolein was substituted with phytantriol as monoolein gets degraded in the presence of lipase when administered orally with consequent loss of liquid crystalline structure. It was confirmed that there was no difference in particle size, entrapment efficiency and nature of product formed by using monoolein or phytantriol. The best formulation was found to be F9, having particle size 104.19 ± 0.21 nm and entrapment efficiency 91.40 ± 0.10%. In vitro release at the end of 12h was found to be 56.45% and zeta potential to be -23.14 mV which stabilized the cubic phase dispersions. It was further characterized for TEM, small angle X-ray scattering (SAXS), DSC and stability studies. SAXS revealed Pn3m space group, indicating a diamond cubic phase which was further confirmed by TEM. Pharmacokinetics of EFV was studied in male Wistar rats. EFV-loaded cubosome dispersions exhibited 1.93 and 1.62-fold increase in peak plasma concentration (Cmax) and 1.48 and 1.42-fold increase in AUC in comparison to that of a suspension prepared with the contents of EFV capsules suspended in 1.5% carboxymethylcellulose PBS solution (pH 5.0), and an EFV solution in medium

Can voluntary pooled procurement reduce the price of antiretroviral drugs? a case study of Efavirenz.

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Kim, Sung Wook; Skordis-Worrall, Jolene

2017-05-01

: A number of strategies have aimed to assist countries in procuring antiretroviral therapy (ARV) at lower prices. In 2009, as the Global Fund to Fight AIDS, Tuberculosis and Malaria (GFATM) commenced a voluntary pooled procurement scheme, however, the impact of the scheme on ARV prices remains uncertain. This study aims to estimate the effect of VPP on drug prices using Efavirenz as a case study. This analysis uses WHO Global price report mechanism (GPRM) data from 2004 to 2013. Due to the highly skewed distribution of drug Prices, a generalized linear model (GLM) was used to conduct a difference-in-difference estimation of drug price changes over time. These analyses found that voluntary pooled procurement reduced both the ex-works price of generic Efavirenz and the incoterms price by 16.2 and 19.1%, respectively ( P <  0.001) in both cases). The year dummies were also statistically significant from 2006 to 2013 ( P <  0.001), indicating a strong decreasing trend in the price of Efavirenz over that period. Voluntary pooled procurement significantly reduced the price of 600 mg generic Efavirenz between 2009 and 2013. Voluntary pooled procurement therefore offers a potentially effective strategy for the reduction in HIV drug prices and the improvement of technical efficiency in HIV programming. Further work is required to establish if these findings hold also for other drugs. © The Author 2017. Published by Oxford University Press in association with The London School of Hygiene and Tropical Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Lipid profiles for etravirine versus efavirenz in treatment-naive patients in the randomized, double-blind SENSE trial

DEFF Research Database (Denmark)

Fätkenheuer, G; Duvivier, C; Rieger, A

2012-01-01

Etravirine is approved for use in treatment-experienced patients at a dose of 200 mg twice daily. Efavirenz has been associated with greater increases in serum lipids compared with other non-nucleosides in randomized trials of first-line treatment.......Etravirine is approved for use in treatment-experienced patients at a dose of 200 mg twice daily. Efavirenz has been associated with greater increases in serum lipids compared with other non-nucleosides in randomized trials of first-line treatment....

Development and validation of reversed-phase HPLC gradient method for the estimation of efavirenz in plasma.

Directory of Open Access Journals (Sweden)

Shweta Gupta

Full Text Available Efavirenz is an anti-viral agent of non-nucleoside reverse transcriptase inhibitor category used as a part of highly active retroviral therapy for the treatment of infections of human immune deficiency virus type-1. A simple, sensitive and rapid reversed-phase high performance liquid chromatographic gradient method was developed and validated for the determination of efavirenz in plasma. The method was developed with high performance liquid chromatography using Waters X-Terra Shield, RP18 50 x 4.6 mm, 3.5 μm column and a mobile phase consisting of phosphate buffer pH 3.5 and Acetonitrile. The elute was monitored with the UV-Visible detector at 260 nm with a flow rate of 1.5 mL/min. Tenofovir disoproxil fumarate was used as internal standard. The method was validated for linearity, precision, accuracy, specificity, robustness and data obtained were statistically analyzed. Calibration curve was found to be linear over the concentration range of 1-300 μg/mL. The retention times of efavirenz and tenofovir disoproxil fumarate (internal standard were 5.941 min and 4.356 min respectively. The regression coefficient value was found to be 0.999. The limit of detection and the limit of quantification obtained were 0.03 and 0.1 μg/mL respectively. The developed HPLC method can be useful for quantitative pharmacokinetic parameters determination of efavirenz in plasma.

Importance of ethnicity, CYP2B6 and ABCB1 genotype for efavirenz pharmacokinetics and treatment outcomes: a parallel-group prospective cohort study in two sub-Saharan Africa populations.

Directory of Open Access Journals (Sweden)

Eliford Ngaimisi

Full Text Available We evaluated the importance of ethnicity and pharmacogenetic variations in determining efavirenz pharmacokinetics, auto-induction and immunological outcomes in two African populations.ART naïve HIV patients from Ethiopia (n = 285 and Tanzania (n = 209 were prospectively enrolled in parallel to start efavirenz based HAART. CD4+ cell counts were determined at baseline, 12, 24 and 48 weeks. Plasma and intracellular efavirenz and 8-hydroxyefvairenz concentrations were determined at week 4 and 16. Genotyping for common functional CYP2B6, CYP3A5, ABCB1, UGT2B7 and SLCO1B1 variant alleles were done.Patient country, CYP2B6*6 and ABCB1 c.4036A>G (rs3842A>G genotype were significant predictors of plasma and intracellular efavirenz concentration. CYP2B6*6 and ABCB1 c.4036A>G (rs3842 genotype were significantly associated with higher plasma efavirenz concentration and their allele frequencies were significantly higher in Tanzanians than Ethiopians. Tanzanians displayed significantly higher efavirenz plasma concentration at week 4 (pG genotype. Within country analyses indicated a significant decrease in the mean plasma efavirenz concentration by week 16 compared to week 4 in Tanzanians (p = 0.006, whereas no significant differences in plasma concentration over time was observed in Ethiopians (p = 0.84. Intracellular efavirenz concentration and patient country were significant predictors of CD4 gain during HAART.We report substantial differences in efavirenz pharmacokinetics, extent of auto-induction and immunologic recovery between Ethiopian and Tanzanian HIV patients, partly but not solely, due to pharmacogenetic variations. The observed inter-ethnic variations in efavirenz plasma exposure may possibly result in varying clinical treatment outcome or adverse event profiles between populations.

Enhancement of Solubility, Dissolution rate and Bioavailability of Efavirenz by Cyclodextrins and Solutol HS15 - A Factorial Study

OpenAIRE

R. Yogananda; K. P. R. Chowdary

2013-01-01

Efavirenz widely prescribed anti-retroviral drug belongs to class II BCS and exhibit low and variable oral bioavailability due to its poor aqueous solubility and it requires enhancement in solubility and dissolution rate for increasing its oral bioavailability. The objective of the present investigation is to enhance the solubility, dissolution rate and bioavailability of efavirenz by the use of cyclodextrins (%CD and HP%CD) and surfactant, Solutol HS15. The individual main effects and combin...

Efavirenz and 8-hydroxyefavirenz induce cell death via a JNK- and BimEL-dependent mechanism in primary human hepatocytes

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Bumpus, Namandje N., E-mail: nbumpus1@jhmi.edu

2011-12-15

Chronic use of efavirenz (EFV) has been linked to incidences of hepatotoxicity in patients receiving EFV to treat HIV-1. While recent studies have demonstrated that EFV stimulates hepatic cell death a role for the metabolites of efavirenz in this process has yet to be examined. In the present study, incubation of primary human hepatocytes with synthetic 8-hydroxyEFV (8-OHEFV), which is the primary metabolite of EFV, resulted in cell death, caspase-3 activation and reactive oxygen species formation. The metabolite exerted these effects at earlier time points and using lower concentrations than were required for the parent compound. In addition, pharmacological inhibition of cytochrome P450-dependent metabolism of EFV using 1-aminobenzotriazole markedly decreased reactive oxygen species formation and cell death. Treatment of primary human hepatocytes with EFV and 8-OHEFV also stimulated phosphorylation of c-Jun N-terminal kinase (JNK) as well as phosphorylation of the JNK substrate c-Jun. Further, the mRNA and protein expression of an isoform of Bim (Bcl-2 interacting mediator of cell death) denoted as BimEL, which is proapoptotic and has been shown to be modulated by JNK, was increased. Inhibition of JNK using SP600125 prevented the EFV- and 8-OHEFV-mediated cell death. Silencing of Bim using siRNA transfected into hepatocytes also prevented cell death resulting from 8-OHEFV-treatment. These data suggest that the oxidative metabolite 8-OHEFV is a more potent inducer of hepatic cell death than the parent compound EFV. Further, activation of the JNK signaling pathway and BimEL mRNA expression appear to be required for EFV- and 8-OHEFV-mediated hepatocyte death. -- Highlights: Black-Right-Pointing-Pointer 8-Hydroxyefavirenz is a more potent stimulator of cell death than efavirenz. Black-Right-Pointing-Pointer Efavirenz and 8-hydroxyefavirenz increase JNK activity and BimEL mRNA expression. Black-Right-Pointing-Pointer JNK and Bim are required for efavirenz- and 8

Long term adverse drug reaction to Efavirenz in a HIV infected ...

African Journals Online (AJOL)

There is only one published case of serious adverse reaction to Efavirenz in an adolescent after long-term use. The case of a male HIV Positive Nigerian patient aged 13 years. He presented with five-day history of Difficulty sleeping, abnormal dreams, inability to concentrate, restlessness, irrational behavior and long-term ...

Lipid-based nutrient supplements do not affect efavirenz but lower plasma nevirapine concentrations in Ethiopian adult HIV patients

DEFF Research Database (Denmark)

Abdissa, A; Olsen, Mette Frahm; Yilma, D

2015-01-01

OBJECTIVES: Lipid-based nutrient supplements (LNSs) are increasingly used in HIV programmes in resource-limited settings. However, the possible effects of LNSs on the plasma concentrations of antiretroviral drugs have not been assessed. Here, we aimed to assess the effects of LNSs on plasma...... efavirenz and nevirapine trough concentrations in Ethiopian adult HIV-infected patients. METHODS: The effects of LNSs were studied in adults initiating antiretroviral therapy (ART) in a randomized trial. Patients with body mass index (BMI) > 17 kg/m(2) (n = 282) received daily supplementation of an LNS.......9; -0.9 μg/mL; P = 0.01), respectively, compared with the group not receiving supplements. There were no differences between groups with respect to efavirenz plasma concentrations. The CYP2B6 516 G>T polymorphism was associated with a 5 μg/mL higher plasma efavirenz concentration compared with the wild...

Pregnancy rates in HIV-positive women using contraceptives and efavirenz-based or nevirapine-based antiretroviral therapy in Kenya: a retrospective cohort study.

Science.gov (United States)

Patel, Rena C; Onono, Maricianah; Gandhi, Monica; Blat, Cinthia; Hagey, Jill; Shade, Starley B; Vittinghoff, Eric; Bukusi, Elizabeth A; Newmann, Sara J; Cohen, Craig R

2015-11-01

Concerns have been raised about efavirenz reducing the effectiveness of contraceptive implants. We aimed to establish whether pregnancy rates differ between HIV-positive women who use various contraceptive methods and either efavirenz-based or nevirapine-based antiretroviral therapy (ART) regimens. We did this retrospective cohort study of HIV-positive women aged 15-45 years enrolled in 19 HIV care facilities supported by Family AIDS Care and Education Services in western Kenya between Jan 1, 2011, and Dec 31, 2013. Our primary outcome was incident pregnancy diagnosed clinically. The primary exposure was a combination of contraceptive method and efavirenz-based or nevirapine-based ART regimen. We used Poisson models, adjusting for repeated measures, and demographic, behavioural, and clinical factors, to compare pregnancy rates among women receiving different contraceptive and ART combinations. 24,560 women contributed 37,635 years of follow-up with 3337 incident pregnancies. In women using implants, adjusted pregnancy incidence was 1.1 per 100 person-years (95% CI 0.72-1.5) for nevirapine-based ART users and 3.3 per 100 person-years (1.8-4.8) for efavirenz-based ART users (adjusted incidence rate ratio [IRR] 3.0, 95% CI 1.3-4.6). In women using depot medroxyprogesterone acetate, adjusted pregnancy incidence was 4.5 per 100 person-years (95% CI 3.7-5.2) for nevirapine-based ART users and 5.4 per 100 person-years (4.0-6.8) for efavirenz-based ART users (adjusted IRR 1.2, 95% CI 0.91-1.5). Women using other contraceptive methods, except for intrauterine devices and permanent methods, had 3.1-4.1 higher rates of pregnancy than did those using implants, with 1.6-2.8 higher rates in women using efavirenz-based ART. Although HIV-positive women using implants and efavirenz-based ART had a three-times higher risk of contraceptive failure than did those using nevirapine-based ART, these women still had lower contraceptive failure rates than did those receiving all other

Effects to chronic administration of Efavirenz on the body and brain ...

African Journals Online (AJOL)

The rats of both sexes (n=16), with the average weight of 200g were randomly assigned into treatment (n=8) and control (n=8) groups. The rats in the treatment group received 8.57mg/kg bogy weight of Efavirenz dissolved in distilled water daily for 30 days (thirty days) through the orogastric tube. The control group received ...

Efavirenz, tenofovir and emtricitabine combined with first-line tuberculosis treatment in tuberculosis-HIV-coinfected Tanzanian patients: a pharmacokinetic and safety study.

Science.gov (United States)

Semvua, Hadija H; Mtabho, Charles M; Fillekes, Quirine; van den Boogaard, Jossy; Kisonga, Riziki M; Mleoh, Liberate; Ndaro, Arnold; Kisanga, Elton R; van der Ven, Andre; Aarnoutse, Rob E; Kibiki, Gibson S; Boeree, Martin J; Burger, David M

2013-01-01

To evaluate the effect of rifampicin-based tuberculosis (TB) treatment on the pharmacokinetics of efavirenz/tenofovir/emtricitabine in a fixed-dose combination tablet, and vice versa, in Tanzanian TB-HIV-coinfected patients. This was a Phase II open-label multiple dose pharmacokinetic and safety study. This study was conducted in TB-HIV-coinfected Tanzanian patients who started TB treatment (rifampicin/isoniazid/pyrazinamide/ethambutol) at week 1 to week 8 and continued with rifampicin and isoniazid for another 16 weeks. Antiretroviral treatment (ART) of efavirenz/tenofovir/emtricitabine in a fixed-dose combination tablet was started at week 4 after initiation of TB treatment. A 24-h pharmacokinetic sampling curve was recorded at week 8 (with TB treatment) and week 28 (ART alone). For TB drugs, blood samples at 2 and 5 h post-dose were taken at week 3 (TB treatment alone) and week 8 (with ART). A total of 25 patients (56% male) completed the study; 21 had evaluable pharmacokinetic profiles. The area under the concentration-time curve 0-24 h post-dose of efavirenz, tenofovir and emtricitabine were slightly higher when these drugs were coadministered with TB drugs; geometric mean ratios (90% CI) were 1.08 (0.90, 1.30), 1.13 (0.93, 1.38) and 1.05 (0.85, 1.29), respectively. For TB drugs, equivalence was suggested for peak plasma concentrations when administered with and without efavirenz/tenofovir/emtricitabine. Adverse events were mostly mild and no serious adverse events or drug discontinuations were reported. Coadministration of efavirenz, tenofovir and emtricitabine with a standard first-line TB treatment regimen did not significantly alter the pharmacokinetic parameters of these drugs and was tolerated well by Tanzanian TB patients who are coinfected with HIV.

Efficacy and safety of rilpivirine (TMC278) versus efavirenz at 48 weeks in treatment-naive HIV-1-infected patients: pooled results from the phase 3 double-blind randomized ECHO and THRIVE Trials.

Science.gov (United States)

Cohen, Calvin J; Molina, Jean-Michel; Cahn, Pedro; Clotet, Bonaventura; Fourie, Jan; Grinsztejn, Beatriz; Wu, Hao; Johnson, Margaret A; Saag, Michael; Supparatpinyo, Khuanchai; Crauwels, Herta; Lefebvre, Eric; Rimsky, Laurence T; Vanveggel, Simon; Williams, Peter; Boven, Katia

2012-05-01

Pooled analysis of phase 3, double-blind, double-dummy ECHO and THRIVE trials comparing rilpivirine (TMC278) and efavirenz. Treatment-naive HIV-1-infected adults were randomized 1:1 to rilpivirine 25 mg once daily or efavirenz 600 mg once daily, with background tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) (ECHO) or TDF/FTC, zidovudine/lamivudine, or abacavir/lamivudine (THRIVE). The primary endpoint was confirmed response [viral load effects on virologic failure were more apparent with rilpivirine. CD4 cell count increased over time in both groups. Rilpivirine compared with efavirenz gave smaller incidences of adverse events leading to discontinuation (3% vs. 8%, respectively), treatment-related grade 2-4 adverse events (16% vs. 31%), rash (3% vs. 14%), dizziness (8% vs. 26%), abnormal dreams/nightmares (8% vs. 13%), and grade 2-4 lipid abnormalities. At week 48, rilpivirine 25 mg once daily and efavirenz 600 mg once daily had comparable response rates. Rilpivirine had more virologic failures and improved tolerability versus efavirenz.

Comprehensive Evaluation for Substrate Selectivity of Cynomolgus Monkey Cytochrome P450 2C9, a New Efavirenz Oxidase.

Science.gov (United States)

Hosaka, Shinya; Murayama, Norie; Satsukawa, Masahiro; Uehara, Shotaro; Shimizu, Makiko; Iwasaki, Kazuhide; Iwano, Shunsuke; Uno, Yasuhiro; Yamazaki, Hiroshi

2015-07-01

Cynomolgus monkeys are widely used as primate models in preclinical studies, because of their evolutionary closeness to humans. In humans, the cytochrome P450 (P450) 2C enzymes are important drug-metabolizing enzymes and highly expressed in livers. The CYP2C enzymes, including CYP2C9, are also expressed abundantly in cynomolgus monkey liver and metabolize some endogenous and exogenous substances like testosterone, S-mephenytoin, and diclofenac. However, comprehensive evaluation regarding substrate specificity of monkey CYP2C9 has not been conducted. In the present study, 89 commercially available drugs were examined to find potential monkey CYP2C9 substrates. Among the compounds screened, 20 drugs were metabolized by monkey CYP2C9 at a relatively high rates. Seventeen of these compounds were substrates or inhibitors of human CYP2C9 or CYP2C19, whereas three drugs were not, indicating that substrate specificity of monkey CYP2C9 resembled those of human CYP2C9 or CYP2C19, with some differences in substrate specificities. Although efavirenz is known as a marker substrate for human CYP2B6, efavirenz was not oxidized by CYP2B6 but by CYP2C9 in monkeys. Liquid chromatography-mass spectrometry analysis revealed that monkey CYP2C9 and human CYP2B6 formed the same mono- and di-oxidized metabolites of efavirenz at 8 and 14 positions. These results suggest that the efavirenz 8-oxidation could be one of the selective markers for cynomolgus monkey CYP2C9 among the major three CYP2C enzymes tested. Therefore, monkey CYP2C9 has the possibility of contributing to limited specific differences in drug oxidative metabolism between cynomolgus monkeys and humans. Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.

A retrospective cohort analysis comparing pregnancy rates among HIV-positive women using contraceptives and efavirenz- or nevirapine-based antiretroviral therapy in Kenya

Science.gov (United States)

PATEL, Rena C.; ONONO, Maricianah; GANDHI, Monica; BLAT, Cinthia; HAGEY, Jill; SHADE, Starley B.; VITTINGHOFF, Eric; BUKUSI, Elizabeth A.; NEWMANN, Sara J.; COHEN, Craig R.

2015-01-01

SUMMARY Background Given recent concerns of efavirenz reducing the efficacy of contraceptive implants, we sought to determine if pregnancy rates differ among HIV-positive women using various contraceptive methods and efavirenz- or nevirapine-based antiretroviral therapy (ART) regimens. Methods We conducted a retrospective cohort analysis of HIV-positive women aged 15–45 years enrolled in HIV care facilities in western Kenya from January 2011 to December 2013. Pregnancy was diagnosed clinically and the primary exposure was a combination of contraceptive method and ART regimen. We used Poisson models, adjusting for repeated measures, as well as demographic, behavioral and clinical factors, to compare pregnancy rates among women on different contraceptive/ART combinations. Findings 24,560 women contributed 37,635 years of follow-up with 3,337 incident pregnancies. Among women using implants, adjusted pregnancy incidence for nevirapine- and efavirenz-based ART users were 1·1 (95% CI 0·72–1·5) and 3·3 (95% CI 1·8–4·8) per 100 women-years (w-y), respectively (adjusted incidence rate ratio (aIRR) 3·0, 95% CI 1·3–4·6). Among women using depomedroxyprogesterone acetate (DMPA), adjusted pregnancy incidence for nevirapine- and efavirenz-based ART users were 4·5 (95% CI 3·7–5·2) and 5·4 (95% CI 4·0–6·8) per 100 w-y, respectively (aIRR 1·2, 95% CI 0·91–1·5). Women using other contraceptive methods, except for intrauterine devices and permanent methods, experienced 3·1–4·1 higher rates of pregnancy than women using implants, with 1·6–2·8 higher rates specifically among women using efavirenz-based ART. Interpretation While HIV-positive women using implants on efavirenz-based ART faced three times higher risk of contraceptive failure than those on nevirapine-based ART, these women still experienced lower contraceptive failure rates than women on all other contraceptive methods, except for intrauterine devices and permanent methods

PXR and CAR single nucleotide polymorphisms influence plasma efavirenz levels in South African HIV/AIDS patients

Directory of Open Access Journals (Sweden)

Swart Marelize

2012-11-01

Full Text Available Abstract Background This study investigated variation in NR1I2 and NR1I3 and its effect on plasma efavirenz levels in HIV/AIDS patients. Variability in plasma drug levels has largely led research on identifying causative variants in drug metabolising enzyme (DME genes, with little focus on the nuclear receptor genes NR1I2 and NR1I3, coding for PXR and CAR, respectively, that are involved in regulating DMEs. Methods 464 Bantu-speaking South Africans comprising of HIV/AIDS patients on efavirenz-based treatment (n=301 and 163 healthy subjects were genotyped for 6 SNPs in NR1I2 and NR1I3. 32 of the 301 patients had their DNA binding domains (DBDs in NR1I2 and NR1I3 sequenced. Results Significantly decreased efavirenz plasma concentrations were observed in patients carrying the NR1I3 rs3003596C/C and T/C genotypes (P=0.015 and P=0.010, respectively. Sequencing resulted in the discovery of a further 13 SNPs, 3 of which are novel variants in the DBD of NR1I2. There were significant differences in the distribution of NR1I2 and NR1I3 SNPs between South Africans when compared to Caucasian, Asian and Yoruba population groups. Conclusion For the realisation of personalised medicine, PXR and CAR genetic variation should be taken into consideration because of their involvement in the regulation of DMEs.

Predicting Optimal Dihydroartemisinin-Piperaquine Regimens to Prevent Malaria During Pregnancy for Human Immunodeficiency Virus-Infected Women Receiving Efavirenz.

Science.gov (United States)

Wallender, Erika; Vucicevic, Katarina; Jagannathan, Prasanna; Huang, Liusheng; Natureeba, Paul; Kakuru, Abel; Muhindo, Mary; Nakalembe, Mirium; Havlir, Diane; Kamya, Moses; Aweeka, Francesca; Dorsey, Grant; Rosenthal, Philip J; Savic, Radojka M

2018-03-05

A monthly treatment course of dihydroartemisinin-piperaquine (DHA-PQ) effectively prevents malaria during pregnancy. However, a drug-drug interaction pharmacokinetic (PK) study found that pregnant human immunodeficiency virus (HIV)-infected women receiving efavirenz-based antiretroviral therapy (ART) had markedly reduced piperaquine (PQ) exposure. This suggests the need for alternative DHA-PQ chemoprevention regimens in this population. Eighty-three HIV-infected pregnant women who received monthly DHA-PQ and efavirenz contributed longitudinal PK and corrected QT interval (QTc) (n = 25) data. Population PK and PK-QTc models for PQ were developed to consider the benefits (protective PQ coverage) and risks (QTc prolongation) of alternative DHA-PQ chemoprevention regimens. Protective PQ coverage was defined as maintaining a concentration >10 ng/mL for >95% of the chemoprevention period. PQ clearance was 4540 L/day. With monthly DHA-PQ (2880 mg PQ), 96% of women, respectively. All regimens were safe, with ≤2% of women predicted to have ≥30 msec QTc increase. For HIV-infected pregnant women receiving efavirenz, low daily DHA-PQ dosing was predicted to improve protection against parasitemia and reduce risk of toxicity compared to monthly dosing. NCT02282293. © The Author(s) 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.

Comparison of genotypic resistance profiles and virological response between patients starting nevirapine and efavirenz in EuroSIDA

DEFF Research Database (Denmark)

Bannister, Wendy P; Ruiz, Lidia; Cozzi-Lepri, Alessandro

2008-01-01

OBJECTIVE: To compare virological outcome and genotypic resistance profiles in HIV-1-infected patients starting non-nucleoside reverse transcriptase inhibitor (NNRTI)-containing regimens. METHODS: NNRTI-naive patients were included who started treatment with nevirapine (NVP) or efavirenz (EFV) wi...

Efficacy and safety of maraviroc versus efavirenz, both with zidovudine/lamivudine: 96-week results from the MERIT study.

Science.gov (United States)

Sierra-Madero, Juan; Di Perri, Giovanni; Wood, Robin; Saag, Michael; Frank, Ian; Craig, Charles; Burnside, Robert; McCracken, Jennifer; Pontani, Dennis; Goodrich, James; Heera, Jayvant; Mayer, Howard

2010-01-01

The MERIT study evaluated maraviroc versus efavirenz, both with zidovudine/lamivudine, in treatment-naïve patients with CCR5-tropic (R5) HIV-1. Post hoc analyses previously assessed week 48 outcomes in patients rescreened with R5 virus by a more sensitive tropism assay. Week 96 efficacy (post hoc, n = 614) and safety (n = 721) were assessed. Proportions of subjects <50 copies/mL (58.8% maraviroc, 62.7% efavirenz) and time to loss of virologic response (TLOVR) responders (<50 copies/mL: 60.5% vs 60.7%) were similar. Maraviroc recipients had greater CD4 increases (+ 212 vs + 171 cells/mm(3)) and fewer adverse event discontinuations (6.1% vs 15.5%), malignancies, and category C events. Week 96 data confirm week 48 observations in MERIT.

Concomitant contraceptive implant and efavirenz use in women living with HIV: perspectives on current evidence and policy implications for family planning and HIV treatment guidelines.

Science.gov (United States)

Patel, Rena C; Morroni, Chelsea; Scarsi, Kimberly K; Sripipatana, Tabitha; Kiarie, James; Cohen, Craig R

2017-05-11

Preventing unintended pregnancies is important among all women, including those living with HIV. Increasing numbers of women, including HIV-positive women, choose progestin-containing subdermal implants, which are one of the most effective forms of contraception. However, drug-drug interactions between contraceptive hormones and efavirenz-based antiretroviral therapy (ART) may reduce implant effectiveness. We present four inter-related perspectives on this issue. First, as a case study, we discuss how limited data prompted country-level guidance against the use of implants among women concomitantly using efavirenz in South Africa and its subsequent negative effects on the use of implants in general. Second, we discuss the existing clinical data on this topic, including the observational study from Kenya showing women using implants plus efavirenz-based ART had three-fold higher rates of pregnancy than women using implants plus nevirapine-based ART. However, the higher rates of pregnancy in the implant plus efavirenz group were still lower than the pregnancy rates among women using common alternative contraceptive methods, such as injectables. Third, we discuss the four pharmacokinetic studies that show 50-70% reductions in plasma progestin concentrations in women concurrently using efavirenz-based ART as compared to women not on any ART. These pharmacokinetic studies provide the biologic basis for the clinical findings. Fourth, we discuss how data on this topic have marked implications for both family planning and HIV programmes and policies globally. This controversy underlines the importance of integrating family planning services into routine HIV care, counselling women appropriately on increased risk of pregnancy with concomitant implant and efavirenz use, and expanding contraceptive method mix for all women. As global access to ART expands, greater research is needed to explore implant effectiveness when used concomitantly with newer ART regimens. Data on how

The effect of efavirenz versus nevirapine-containing regimens on immunologic, virologic and clinical outcomes in a prospective observational study

NARCIS (Netherlands)

Collaboration, H.-C.; Koopmans †, P.P.; Brouwer, A.M.; Dofferhoff, A.S.M.; Flier, M. van der; Groot, R. de; Hofstede, H.J.M. ter; Keuter, M.; Ven, A.J.A.M. van der; et al.,

2012-01-01

OBJECTIVE: To compare regimens consisting of either efavirenz or nevirapine and two or more nucleoside reverse transcriptase inhibitors (NRTIs) among HIV-infected, antiretroviral-naive, and AIDS-free individuals with respect to clinical, immunologic, and virologic outcomes. DESIGN: Prospective

Safety, strength and simplicity of efavirenz in pregnancy

Directory of Open Access Journals (Sweden)

Prinitha Pillay

2012-03-01

Full Text Available The WHO recommends starting lifelong ART for all pregnant women with a CD4 count at or below 350 cells/mm³, which recognises the important component of ‘when to start’ and the role that timing of initiation plays in reducing mortality and disease progression. The data on ‘what to start’ are conflicting, and options for resource-limited settings are limited. The choice of an ART regimen for pregnant women is complicated by the need to take into account the health and safety of both the mother and baby. Particularly contentious is whether to use a nevirapine- (NVP or efavirenz- (EFV based regimen. This review presents the latest evidence on the safety and efficacy of EFV and NVP in pregnancy and offers recommendations for improving maternal and child health outcomes and avoid mother-to-child transmission as South Africa moves toward turning back the tide on its HIV epidemic.

Efavirenz, tenofovir and emtricitabine combined with first-line tuberculosis treatment in tuberculosis-HIV-coinfected Tanzanian patients: a pharmacokinetic and safety study

NARCIS (Netherlands)

Semvua, H.H.; Mtabho, C.M.; Fillekes, Q.; Boogaard, J. van den; Kisonga, R.M.; Mleoh, L.; Ndaro, A.; Kisanga, E.R.; Ven, A. van der; Aarnoutse, R.E.; Kibiki, G.S.; Boeree, M.J.; Burger, D.M.

2013-01-01

BACKGROUND: To evaluate the effect of rifampicin-based tuberculosis (TB) treatment on the pharmacokinetics of efavirenz/tenofovir/emtricitabine in a fixed-dose combination tablet, and vice versa, in Tanzanian TB-HIV-coinfected patients. METHODS: This was a Phase II open-label multiple dose

Design and formulation of nano-sized spray dried efavirenz-part I: influence of formulation parameters

Energy Technology Data Exchange (ETDEWEB)

Katata, Lebogang, E-mail: lebzakate@yahoo.com; Tshweu, Lesego; Naidoo, Saloshnee; Kalombo, Lonji; Swai, Hulda [Materials Science and Manufacturing, Centre of Polymers and Composites, Council for Scientific and Industrial Research (South Africa)

2012-11-15

Efavirenz (EFV) is one of the first-line antiretroviral drugs recommended by the World Health Organisation for treating HIV. It is a hydrophobic drug that suffers from low aqueous solubility (4 {mu}g/mL), which leads to a limited oral absorption and low bioavailability. In order to improve its oral bioavailability, nano-sized polymeric delivery systems are suggested. Spray dried polycaprolactone-efavirenz (PCL-EFV) nanoparticles were prepared by the double emulsion method. The Taguchi method, a statistical design with an L{sub 8} orthogonal array, was implemented to optimise the formulation parameters of PCL-EFV nanoparticles. The types of sugar (lactose or trehalose), surfactant concentration and solvent (dichloromethane and ethyl acetate) were chosen as significant parameters affecting the particle size and polydispersity index (PDI). Small nanoparticles with an average particle size of less than 254 {+-} 0.95 nm in the case of ethyl acetate as organic solvent were obtained as compared to more than 360 {+-} 19.96 nm for dichloromethane. In this study, the type of solvent and sugar were the most influencing parameters of the particle size and PDI. Taguchi method proved to be a quick, valuable tool in optimising the particle size and PDI of PCL-EFV nanoparticles. The optimised experimental values for the nanoparticle size and PDI were 217 {+-} 2.48 nm and 0.093 {+-} 0.02.

Design and formulation of nano-sized spray dried efavirenz-part I: influence of formulation parameters

International Nuclear Information System (INIS)

Katata, Lebogang; Tshweu, Lesego; Naidoo, Saloshnee; Kalombo, Lonji; Swai, Hulda

2012-01-01

Efavirenz (EFV) is one of the first-line antiretroviral drugs recommended by the World Health Organisation for treating HIV. It is a hydrophobic drug that suffers from low aqueous solubility (4 μg/mL), which leads to a limited oral absorption and low bioavailability. In order to improve its oral bioavailability, nano-sized polymeric delivery systems are suggested. Spray dried polycaprolactone-efavirenz (PCL-EFV) nanoparticles were prepared by the double emulsion method. The Taguchi method, a statistical design with an L 8 orthogonal array, was implemented to optimise the formulation parameters of PCL-EFV nanoparticles. The types of sugar (lactose or trehalose), surfactant concentration and solvent (dichloromethane and ethyl acetate) were chosen as significant parameters affecting the particle size and polydispersity index (PDI). Small nanoparticles with an average particle size of less than 254 ± 0.95 nm in the case of ethyl acetate as organic solvent were obtained as compared to more than 360 ± 19.96 nm for dichloromethane. In this study, the type of solvent and sugar were the most influencing parameters of the particle size and PDI. Taguchi method proved to be a quick, valuable tool in optimising the particle size and PDI of PCL-EFV nanoparticles. The optimised experimental values for the nanoparticle size and PDI were 217 ± 2.48 nm and 0.093 ± 0.02.

Antioxidants as recipes for efavirenz-induced liver damage: A study in albino rats

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Elias Adikwu

2018-03-01

Full Text Available Objective: Hepatotoxicity is a clinical challenge associated with the use of efavirenz (EFV. This study investigated the effects of n-acetylcysteine (NAC, vitamins C and E on EFV-induced hepatotoxicity in albino rats. Methods: Rats were divided into groups and administered with NAC (20mg/kg, Vit C (50mg/kg, Vit  E (50mg/kg, Vit C+ E and 60mg/kg of EFV respectively. Rats were also divided into groups and pretreated with NAC, Vit C, E, and combined doses of Vit C+E prior to treatment with EFV for 15 days respectively. After drug administration rats were sacrificed and serum was collected and evaluated for liver function parameters. Rats were dissected, liver was collected weighed and evaluated for alkaline phosphatase (ALP, alanine aminotransferase (AST, aspartate aminotransferase (ALT, gamma glutamyl transferase (GGT, lactate dehydrogenase (LDH, malondialdehyde (MDA, super oxide dismutase (SOD, catalase (CAT, glutathione (GSH, gluthatione peroxidase (GPX levels and pathological damage. Results: Effects were not significant (p>0.05 on body and liver weights, however, the levels of AST, ALT, AST, GGT, LDH, CB, TB and MDA were increased significantly (p<0.05 whereas SOD, CAT, SOD, GSH and GPX were decreased significantly (p<0.05 in EFV-treated rats in comparison to control. The liver of EFV-treated rats showed necrosis of hepatocytes. Nevertheless, EFV-induced alterations in the above parameters were significantly (p<0.05 ameliorated in antioxidants pretreated rats.  The combined doses of Vit C and E produced the best and significant (p<0.05 ameliorative effects in comparison to their individual doses. Conclusion: This study shows the prospects of antioxidants as candidates for the treatments of efavirenz-induced hepatotoxicity.

The effect of malnutrition on the pharmacokinetics and virologic outcomes of lopinavir, efavirenz and nevirapine in food insecure HIV-infected children in Tororo, Uganda

NARCIS (Netherlands)

Bartelink, Imke H.; Savic, Rada M.; Dorsey, Grant; Ruel, Theodore; Gingrich, David; Scherpbier, Henriette J.; Capparelli, Edmund; Jullien, Vincent; Young, Sera L.; Achan, Jane; Plenty, Albert; Charlebois, Edwin; Kamya, Moses; Havlir, Diane; Aweeka, Francesca

2015-01-01

Malnutrition may impact the pharmacokinetics (PKs) of antiretroviral medications and virologic responses in HIV-infected children. The authors therefore evaluated the PK of nevirapine (NVP), efavirenz (EFV) and lopinavir (LPV) in associations with nutritional status in a cohort of HIV-infected

Lack of association between use of efavirenz and death from suicide

DEFF Research Database (Denmark)

Smith, Colette; Ryom, Lene; Monforte, Antonella d'Arminio

2014-01-01

INTRODUCTION: A recent meta-analysis of 4 RCTs showed an increased rate of suicidality events (suicidal ideation or attempted/completed suicide) associated with efavirenz (EFV) compared to other regimens, but only a trend towards a higher rate of completed/attempted suicides, as only 17 events...... occurred. We investigated the association between EFV use and completed suicide. MATERIALS AND METHODS: All D:A:D participants were followed from study entry to the first of death, last study visit or 1 February 2013. Deaths are centrally validated using cause of death methodology, which assigns underlying......, immediate and up to four contributing causes of death. Two endpoints were considered: 1) suicide or psychiatric disease as the underlying cause, and 2) suicide or psychiatric disease mentioned as an underlying, immediate or contributing cause of death (anywhere). Adjusted rate ratios were calculated using...

Incidence of neuropsychiatric side effects of efavirenz in HIV-positive treatment-naïve patients in public-sector clinics in the Eastern Cape

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Razia Gaida

2016-06-01

Full Text Available Background: It is acknowledged that almost half of patients initiated on efavirenz will experience at least one neuropsychiatric side effect. Objectives: The aim was to determine the incidence and severity of neuropsychiatric side effects associated with efavirenz use in five public-sector primary healthcare clinics in the Eastern Cape. Method: The study was a prospective drug utilisation study. A total of 126 medical records were reviewed to obtain the required information. After baseline assessment, follow-up reviews were conducted at 4 weeks, 12 weeks and 24 weeks from 2014 to 2015. Results: The participant group was 74.60% female (n = 94, and the average age was 37.57±10.60 years. There were no neuropsychiatric side effects recorded for any patient. After the full follow-up period, there were a total of 49 non-adherent patients and one patient had demised. A non-adherent patient was defined as a patient who did not return to the clinic for follow-up assessment and medication refills 30 days or more after the appointed date. Some patients (n = 11 had sent a third party to the clinic to collect their antiretroviral therapy (ART. The clinic pharmacy would at times dispense a two-month supply of medication resulting in the patient presenting only every two months. Conclusion: Further pharmacovigilance studies need to be conducted to determine the true incidence of these side effects. Healthcare staff must be encouraged to keep complete records to ensure meaningful patient assessments. Patients being initiated on ART need to personally attend the clinic monthly for at least the first 6 months of treatment. Clinic staff should receive regular training concerning ART, including changes made to guidelines as well as reminders of side effects experienced. Keywords: neuropsychiatric; side effects; efavirenz; HIV-positive patients

Impact of body weight on virological and immunological responses to efavirenz-containing regimens in HIV-infected, treatment-naive adults

DEFF Research Database (Denmark)

Marzolini, Catia; Sabin, Caroline; Raffi, François

2015-01-01

OBJECTIVE: The prevalence of overweight and obesity is increasing among HIV-infected patients. Whether standard antiretroviral drug dosage is adequate in heavy individuals remains unresolved. We assessed the virological and immunological responses to initial efavirenz (EFV)-containing regimens...... individuals had significantly higher CD4 cell count at baseline, CD4 cell recovery at 6 and 12 months after EFV initiation was comparable to normal-weight individuals. CONCLUSION: Virological and immunological responses to initial EFV-containing regimens were not impaired in heavy individuals, suggesting...

The male genital tract is not a pharmacological sanctuary from efavirenz.

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Avery, L B; Bakshi, R P; Cao, Y J; Hendrix, C W

2011-07-01

Many antiretroviral (ARV) drugs have large blood plasma-to-seminal plasma (BP/SP) concentration ratios. Concern exists that these drugs do not adequately penetrate the male genital tract (MGT), resulting in the MGT becoming a "pharmacological sanctuary" from these agents, with ineffective MGT concentrations despite effective blood concentrations. Efavirenz (EFV) is the most highly protein-bound ARV drug, with >99% binding in blood plasma and the largest BP/SP total EFV concentration ratio, reportedly ranging from 11 to 33. To evaluate protein binding as an explanation for the differences between the drug concentrations in blood and semen, we developed a novel ultrafiltration method, corrected for the duration of centrifugation, to measure protein binding in the two matrices. In six subjects, protein-free EFV concentrations were the same in blood and semen; the median (interquartile range (IQR)) protein-free EFV SP/BP ratio was 1.21 (0.99-1.35); EFV protein binding was 99.82% (99.79-99.86) in BP and 95.26% (93.24-96.67) in SP. This shows that the MGT is not a sanctuary from EFV.

Tribal ethnicity and CYP2B6 genetics in Ugandan and Zimbabwean populations in the UK: implications for efavirenz dosing in HIV infection.

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Jamshidi, Y; Moreton, M; McKeown, D A; Andrews, S; Nithiyananthan, T; Tinworth, L; Holt, D W; Sadiq, S T

2010-12-01

To determine differences in CYP2B6 loss of function (LoF) single nucleotide polymorphisms (SNPs) and haplotypes between Zimbabweans and Ugandans, and within Ugandan populations (Bantu and Nilotic). Genetic epidemiological study enrolling adult black African Ugandan and Zimbabwean patients attending a UK HIV-1 clinic, irrespective of antiretroviral therapy status. Genomic DNA was extracted from whole blood and the presence of CYP2B6 alleles was determined by direct sequencing of all nine exons of the CYP2B6 gene. Blood was also collected, where appropriate, for determination of efavirenz concentrations. Frequency of SNPs in all patients and LoF haplotype frequencies were calculated. The relationship between the number of LoF haplotype alleles possessed and efavirenz trough concentration (ETC) was determined. Thirty-six Zimbabweans and 74 Ugandans (58 Bantu and 16 Nilotic) were recruited. The definite haplotypes determined were *6, *18, *20 and *27 as LoF and *4 as gain of function. Among those with definite genotypes, the frequency of LoF alleles was 65% [95% confidence interval (95% CI): 51-80] of Zimbabweans versus 22% (95% CI: 12-31) of Ugandan Bantus (P = 10(-6)) and versus 39% (95% CI: 14-64) of Ugandan Nilotics (P = 0.09). Among the 19 patients with definite genotype and with available ETCs, log ETCs were associated with a greater number of LoF haplotype alleles [848 ng/mL (n = 12), 1069 ng/mL (n = 4) and 1813 ng/mL (n = 3) for 0, 1 or 2 LoF haplotypes, respectively (P = 0.016)]. Among Zimbabweans, LoF haplotypes constitute the majority of CYP2B6 alleles and are significantly higher in prevalence compared with Ugandans. Frequencies of LoF haplotypes and SNPs in Ugandan Nilotics appear to lie between those of Zimbabweans and Ugandan Bantus. These findings may have relevance to pharmacokinetics and dosing of efavirenz in African populations.

Pharmacokinetic Interactions between the Hormonal Emergency Contraception, Levonorgestrel (Plan B, and Efavirenz

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Monica L. Carten

2012-01-01

Full Text Available Objectives. Compare the Plan B levonorgestrel (LNG area under the concentration- time curve (AUC12 prior to and with efavirenz (EFV. Design. Prospective, open-label, single-arm, equivalence study. Methods. Healthy HIV-negative subjects underwent 12 hr intensive pharmacokinetic (PK sampling following single dose LNG alone and after 14 days of EFV. Geometric means, Geometric Mean Ratios, and 90% confidence intervals (CI are reported for PK Parameters. T-tests were utilized. Clinical parameters and liver function tests (LFTs were assessed. Results. 24 women enrolled and 21 completed the study. With EFV, LNG AUC12 was reduced 56% (95% CI: 49%, 62% from 42.9 to 17.8 ng*hr/mL, and maximum concentration (Cmax⁡ was reduced 41% (95% CI: 33%, 50% from 8.4 to 4.6 ng/mL. LNG was well tolerated with no grade 3 or 4 treatment-related toxicities. Conclusions. EFV significantly reduced LNG exposures. Higher LNG doses may be required with EFV. These results reinforce the importance of effective contraception in women taking EFV.

Issues in resistance, adherence, and comparative efficacy of the single-tablet regimen combination of tenofovir, emtricitabine, and efavirenz in the management of HIV-1 infection

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Rebick G

2012-09-01

Full Text Available Gabriel Rebick, Sharon L WalmsleyDivision of Infectious Diseases, Department of Medicine, University Health Network, University of Toronto, Toronto, ON, CanadaAbstract: Atripla is the first once-daily, single-tablet, triple-combination antiretroviral therapy. It is recommended for the initial treatment of the naïve patient with human immunodeficiency virus-1 (HIV-1 infection in all current guidelines, based on its proven efficacy in numerous head-to-head randomized clinical trials. Not only has it proven efficacy, but the fixed-dose combination, Atripla, has resulted in an improvement in adherence, quality of life, and satisfaction among naïve as well as virally suppressed patients switching from another regimen. Despite the advantages, tolerability issues can arise that are related primarily to the efavirenz component, which is known to cause central nervous side effects such as dizziness, abnormal dreams, and anxiety. Although generally self-limited, these side-effects can lead to treatment discontinuation in the short- or long-term. Based on the observation of neural tube defects in macaque models, and isolated case reports in human fetuses with first trimester exposure, it is rated as Food and Drug Administration pregnancy category D, and considered as contraindicated in the first trimester of pregnancy where alternatives are available. Given the low genetic barrier of each of the individual components, resistance remains an important issue for patients with poor adherence, but is balanced in part by the long half-life of the drugs. Transmitted resistance is described in up to 16% of newly infected patients in population surveys, and is particularly prevalent in men who have sex with men. Minority variants that may impart resistant to efavirenz are not detected with currently used HIV-1 genotype assays, but nonetheless may also be implicated in patients who fail initial treatment. Several single-tablet regimens are recently licensed or in

Solubility and dissolution performances of spray-dried solid dispersion of Efavirenz in Soluplus.

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Lavra, Zênia Maria Maciel; Pereira de Santana, Davi; Ré, Maria Inês

2017-01-01

Efavirenz (EFV), a first-line anti-HIV drug largely used as part of antiretroviral therapies, is practically insoluble in water and belongs to BCS class II (low solubility/high permeability). The aim of this study was to improve the solubility and dissolution performances of EFV by formulating an amorphous solid dispersion of the drug in polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer (Soluplus ® ) using spray-drying technique. To this purpose, spray-dried dispersions of EFV in Soluplus ® at different mass ratios (1:1.25, 1:7, 1:10) were prepared and characterized using particle size measurements, SEM, XRD, DSC, FTIR and Raman microscopy mapping. Solubility and dissolution were determined in different media. Stability was studied at accelerated conditions (40 °C/75% RH) and ambient conditions for 12 months. DSC and XRD analyses confirmed the EFV amorphous state. FTIR spectroscopy analyses revealed possible drug-polymer molecular interaction. Solubility and dissolution rate of EFV was enhanced remarkably in the developed spray-dried solid dispersions, as a function of the polymer concentration. Spray-drying was concluded to be a proper technique to formulate a physically stable dispersion of amorphous EFV in Soluplus ® , when protected from moisture.

Incident AIDS or Death After Initiation of Human Immunodeficiency Virus Treatment Regimens Including Raltegravir or Efavirenz Among Adults in the United States.

Science.gov (United States)

Cole, Stephen R; Edwards, Jessie K; Hall, H Irene; Brookhart, M Alan; Mathews, W Christopher; Moore, Richard D; Crane, Heidi M; Kitahata, Mari M; Mugavero, Michael J; Saag, Michael S; Eron, Joseph J

2017-06-01

The long-term effectiveness of human immunodeficiency virus (HIV) treatments containing integrase inhibitors is unknown. We use observational data from the Centers for AIDS Research Network of Integrated Clinical Systems and the Centers for Disease Control and Prevention to estimate 4-year risk of AIDS and all-cause mortality among 415 patients starting a raltegravir regimen compared to 2646 starting an efavirenz regimen (both regimens include emtricitabine and tenofovir disoproxil fumarate). We account for confounding and selection bias as well as generalizability by standardization for measured variables, and present both observational intent-to-treat and per-protocol estimates. At treatment initiation, 12% of patients were female, 36% black, 13% Hispanic; median age was 37 years, CD4 count 321 cells/µL, and viral load 4.5 log10 copies/mL. Two hundred thirty-five patients incurred an AIDS-defining illness or died, and 741 patients left follow-up. After accounting for measured differences, the 4-year risk was similar among those starting both regimens (ie, intent-to treat hazard ratio [HR], 0.96 [95% confidence interval {CI}, .63-1.45]; risk difference, -0.9 [95% CI, -4.5 to 2.7]), as well as among those remaining on regimens (ie, per-protocol HR, 0.95 [95% CI, .59-1.54]; risk difference, -0.5 [95% CI, -3.8 to 2.9]). Raltegravir and efavirenz-based initial antiretroviral therapy have similar 4-year clinical effects. Vigilance regarding longer-term comparative effectiveness of HIV regimens using observational data is needed because large-scale experimental data are not forthcoming. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.

Improvement of lipoatrophy by switching from efavirenz to lopinavir/ritonavir.

Science.gov (United States)

Rojas, J; Lonca, M; Imaz, A; Estrada, V; Asensi, V; Miralles, C; Domingo, P; Montero, M; del Rio, L; Fontdevila, J; Perez, I; Cruceta, A; Gatell, J M; Arnedo, M; Martínez, E

2016-05-01

To assess whether changes in antiretroviral drugs other than thymidine nucleoside reverse transcriptase inhibitors (NRTI) may have a body fat impact in HIV-infected patients with lipoatrophy. Ninety-six-week phase IV, open-label, multicentre, pilot randomized trial. HIV-infected patients with moderate/severe lipoatrophy at one or more body sites despite long-term thymidine NRTI-free therapy were randomized to continue their efavirenz (EFV)-based antiretroviral regimen or to switch from EFV to lopinavir/ritonavir (LPV/r). The primary endpoint was the absolute change in limb fat mass measured by dual X-ray absorptiometry from baseline to 96 weeks. Changes in other body fat measurements, subjective perception of lipoatrophy, subcutaneous fat gene expression and plasma lipids were also assessed. Thirty-three patients (73% men, median age 52 years) were recruited. At 96 weeks, absolute limb fat mass increased in the LPV/r arm vs. the EFV arm (estimated difference +1082.1 g; 95% CI +63.7 to +2103.5; P = 0.04); this difference remained significant after adjustment by gender, age, fat mass, body mass index and CD4 cell count at baseline. Subjective lipoatrophy perception scores also improved in the LPV/r arm relative to the EFV arm. Adipogenesis, glucose and lipid metabolism, and mitochondrial gene expression increased in the LPV/r arm compared with the EFV arm at 96 weeks. HDL cholesterol decreased in the LPV/r arm relative to the EFV arm. Switching from EFV to LPV/r in HIV-infected patients with lipoatrophy may offer further limb fat gain beyond thymidine NRTI discontinuation, although this strategy decreased plasma HDL cholesterol and caused changes in subcutaneous fat gene expression that may be associated with increased insulin resistance. © 2015 British HIV Association.

Liver enzyme abnormalities and associated risk factors in HIV patients on efavirenz-based HAART with or without tuberculosis co-infection in Tanzania.

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Sabina Mugusi

Full Text Available To investigate the timing, incidence, clinical presentation, pharmacokinetics and pharmacogenetic predictors for antiretroviral and anti-tuberculosis drug induced liver injury (DILI in HIV patients with or without TB co-infection.A total of 473 treatment naïve HIV patients (253 HIV only and 220 with HIV-TB co-infection were enrolled prospectively. Plasma efavirenz concentration and CYP2B6*6, CYP3A5*3, *6 and *7, ABCB1 3435C/T and SLCO1B1 genotypes were determined. Demographic, clinical and laboratory data were collected at baseline and up to 48 weeks of antiretroviral therapy. DILI case definition was according to Council for International Organizations of Medical Sciences (CIOMS. Incidence of DILI and identification of predictors was evaluated using Cox Proportional Hazards Model. The overall incidence of DILI was 7.8% (8.3 per 1000 person-week, being non-significantly higher among patients receiving concomitant anti-TB and HAART (10.0%, 10.7 per 1000 person-week than those receiving HAART alone (5.9%, 6.3 per 1000 person-week. Frequency of CYP2B6*6 allele (p = 0.03 and CYP2B6*6/*6 genotype (p = 0.06 was significantly higher in patients with DILI than those without. Multivariate cox regression model indicated that CYP2B6*6/*6 genotype and anti-HCV IgG antibody positive as significant predictors of DILI. Median time to DILI was 2 weeks after HAART initiation and no DILI onset was observed after 12 weeks. No severe DILI was seen and the gain in CD4 was similar in patients with or without DILI.Antiretroviral and anti-tuberculosis DILI does occur in our setting, presenting early following HAART initiation. DILI seen is mild, transient and may not require treatment interruption. There is good tolerance to HAART and anti-TB with similar immunological outcomes. Genetic make-up mainly CYP2B6 genotype influences the development of efavirenz based HAART liver injury in Tanzanians.

CYP2B6 genotype-based efavirenz dose recommendations during rifampicin-based antituberculosis cotreatment for a sub-Saharan Africa population.

Science.gov (United States)

Mukonzo, Jackson K; Bisaso, Ronald K; Ogwal-Okeng, Jasper; Gustafsson, Lars L; Owen, Joel S; Aklillu, Eleni

2016-04-01

To assess genotype effect on efavirenz (EFV) pharmacokinetics, treatment outcomes and provide genotype-based EFV doses recommendations during for tuberculosis (TB)-HIV-1 cotreatment. EFV concentrations from 158 HIV-TB co-infected patients treated with EFV/lamivudine/zidovidine and rifampicin were analyzed. Genotype and CD4 and viral load data were analyzed using a population PK model. Simulated AUCs for 600 mg EFV dose were 1.2- and 2.4-times greater than the product label for Ugandans in general and CYP2B6*6/*6 genotypes respectively. EFV daily doses of 450 and 250 mg for Ugandans and CYP2B6*6/*6 genotypes, respectively, yielded simulated exposures comparable to the product label. Around 450 and 250 mg daily doses might meet EFV dosing needs of HIV-TB infected Ugandans in general and CYP2B6*6/*6 genotypes, respectively.

Why did the FDA approve efavirenz 800 mg when co-administered with rifampin?

Science.gov (United States)

Liu, Jiang; Chan-Tack, Kirk M; Jadhav, Pravin; Seo, Shirley; Robertson, Sarah M; Kraft, Jeffrey; Singer, Mary E; Struble, Kimberly A; Arya, Vikram

2014-06-01

Literature reports regarding the efficacy of efavirenz (EFV) 600 mg with rifampin (RIF) are not consistent. Evaluation of a drug-drug interaction (DDI) study and supportive semi-mechanistic population pharmacokinetic (PK) analyses were undertaken to help delineate this issue. DDI study and supportive semi-mechanistic population PK analyses were provided by BMS. Population PK analysis was based on six studies with intensive EFV PK sampling. An ACTG study with sparse PK sampling was used for model evaluation. Simulations compared EFV exposure at various doses in combination with RIF to EFV exposures at 600 mg once daily (QD). Effects of CYP2B6 genotypes on the magnitude of EFV-RIF interaction were also explored. In DDI study, co-administering EFV 600 mg QD and RIF reduced mean EFV exposure by ~ 30%. Population PK model provided acceptable predictive performance of central tendency and variability for EFV C0, Cmax, and AUC. Simulations predicted that increasing EFV to 800 mg QD with RIF would result in EFV AUC and Cmax similar to EFV 600 mg QD alone. EFV AUC and Cmax were ~ 2 times higher in subjects with reduced function CYP2B6 genotypes. However, the RIF effect was consistent across all genotypes. EFV dose adjustment to 800 mg QD did not increase the risk of overexposure compared to 600 mg EFV QD within each genotype. Dose adjustment based on matching systemic exposure was recommended to mitigate the potential for sub-therapeutic EFV exposures. Our review did not reveal any safety concerns in subjects receiving EFV 800 mg QD with RIF.

Generalized Probability-Probability Plots

NARCIS (Netherlands)

Mushkudiani, N.A.; Einmahl, J.H.J.

2004-01-01

We introduce generalized Probability-Probability (P-P) plots in order to study the one-sample goodness-of-fit problem and the two-sample problem, for real valued data.These plots, that are constructed by indexing with the class of closed intervals, globally preserve the properties of classical P-P

Quantum Probabilities as Behavioral Probabilities

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Vyacheslav I. Yukalov

2017-03-01

Full Text Available We demonstrate that behavioral probabilities of human decision makers share many common features with quantum probabilities. This does not imply that humans are some quantum objects, but just shows that the mathematics of quantum theory is applicable to the description of human decision making. The applicability of quantum rules for describing decision making is connected with the nontrivial process of making decisions in the case of composite prospects under uncertainty. Such a process involves deliberations of a decision maker when making a choice. In addition to the evaluation of the utilities of considered prospects, real decision makers also appreciate their respective attractiveness. Therefore, human choice is not based solely on the utility of prospects, but includes the necessity of resolving the utility-attraction duality. In order to justify that human consciousness really functions similarly to the rules of quantum theory, we develop an approach defining human behavioral probabilities as the probabilities determined by quantum rules. We show that quantum behavioral probabilities of humans do not merely explain qualitatively how human decisions are made, but they predict quantitative values of the behavioral probabilities. Analyzing a large set of empirical data, we find good quantitative agreement between theoretical predictions and observed experimental data.

Probability Aggregates in Probability Answer Set Programming

OpenAIRE

Saad, Emad

2013-01-01

Probability answer set programming is a declarative programming that has been shown effective for representing and reasoning about a variety of probability reasoning tasks. However, the lack of probability aggregates, e.g. {\\em expected values}, in the language of disjunctive hybrid probability logic programs (DHPP) disallows the natural and concise representation of many interesting problems. In this paper, we extend DHPP to allow arbitrary probability aggregates. We introduce two types of p...

Probable brote de transmisión oral de enfermedad de Chagas en Turbo, Antioquia

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Juan Fernando Ríos

2011-03-01

Conclusión. Se identificó un probable brote agudo de enfermedad de Chagas en Antioquia y se plantea como hipótesis la transmisión por vía oral, mediante la ingestión de T. cruzi en alimentos contaminados con restos de triatominos o excrementos de marsupiales.

Negative probability in the framework of combined probability

OpenAIRE

Burgin, Mark

2013-01-01

Negative probability has found diverse applications in theoretical physics. Thus, construction of sound and rigorous mathematical foundations for negative probability is important for physics. There are different axiomatizations of conventional probability. So, it is natural that negative probability also has different axiomatic frameworks. In the previous publications (Burgin, 2009; 2010), negative probability was mathematically formalized and rigorously interpreted in the context of extende...

Anti-HIV drugs nevirapine and efavirenz affect anxiety-related behavior and cognitive performance in mice.

Science.gov (United States)

Romão, Pedro R T; Lemos, Joelson C; Moreira, Jeverson; de Chaves, Gisele; Moretti, Morgana; Castro, Adalberto A; Andrade, Vanessa M; Boeck, Carina R; Quevedo, João; Gavioli, Elaine C

2011-01-01

Nevirapine (NVP) and efavirenz (EFV) belong to the class of anti-HIV drugs called non-nucleoside reverse transcriptase inhibitors (NNRTIs), commonly used as part of highly active antiretroviral therapy (HAART). Although the HAART is able to bring down viral load to undetectable levels and restore immune function, their prolonged use causes several adverse effects. It has been demonstrated that both NVP and EFV are able to cross the blood-brain barrier, causing important central nervous system-related side effects. Thus, this study investigated the effects of chronic administration of EFV (10 mg/kg) and NVP (3.3 mg/kg) in mice submitted to two distinct series of experiments, which aimed to evaluate: (1) the emotional behavior (elevated plus-maze, forced swimming, and open-field test) and (2) the cognitive performance (object recognition and inhibitory avoidance test) of mice. Our results demonstrated that EFV, but not NVP, reduced the exploration to open arms in the elevated plus-maze test. Neither NVP nor EFV altered mouse behavior in the forced swimming and open-field tests. Both drugs reduced the recognition index in the object recognition test, but only EFV significantly impaired the aversive memory assessed in the inhibitory avoidance test 24 h after training. In conclusion, our findings point to a genuine anxiogenic-like effect to EFV, since it reduced exploration to open arms of elevated plus-maze test without affecting spontaneous locomotion. Additionally, both drugs impaired recognition memory, while only the treatment with EFV impaired significantly aversive memory.

El CO2 como disolvente y como reactivo

OpenAIRE

La Franca Pitarresi, Vincenzo Rosario

2016-01-01

Existen numerosas ventajas asociada con el uso de CO2 , tanto como disolvente que como reactivo, y todas se pueden resumir en cuatro categorías generales: beneficios ambiental, beneficios de salud y seguridad, beneficios en el procedimiento y beneficios químicos. Los procesos que implican el CO2 como disolvente no aumentaría las emisiones de CO2, más bien proporcionaría una oportunidad para el reciclaje de CO2 residual. Además, los esfuerzos para secuestrar el CO2 producido de los gases de co...

Probability

CERN Document Server

Shiryaev, A N

1996-01-01

This book contains a systematic treatment of probability from the ground up, starting with intuitive ideas and gradually developing more sophisticated subjects, such as random walks, martingales, Markov chains, ergodic theory, weak convergence of probability measures, stationary stochastic processes, and the Kalman-Bucy filter Many examples are discussed in detail, and there are a large number of exercises The book is accessible to advanced undergraduates and can be used as a text for self-study This new edition contains substantial revisions and updated references The reader will find a deeper study of topics such as the distance between probability measures, metrization of weak convergence, and contiguity of probability measures Proofs for a number of some important results which were merely stated in the first edition have been added The author included new material on the probability of large deviations, and on the central limit theorem for sums of dependent random variables

Carolee Schneemann. El cine como autobiografía, la artista como actriz, el cuerpo como pincel

Directory of Open Access Journals (Sweden)

María Barbaño González-Moreno

2017-10-01

Full Text Available Este trabajo analiza la relación de cine y mujer a partir de la obra fílmica de Carolee Schneemann, principalmente de su obra autobiográfica Fuses (1964-1966. Desde ella, se plantea el papel de la artista como productora, directora y protagonista principal de todas sus obras. Reflexionamos así sobre el rol del creador-director como actor que derivaría en la consecución de una obra cinematográfica de tintes necesariamente autobiográficos. Asumiendo la visión vanguardista del cine como diario personal/Entendido el cine como diario personal, Schneemann va a explorar en su obra diferentes aspectos de la identidad y la sexualidad de la mujer en un cine artístico, alternativo y de tendencia política feminista. Entendido/Asumido su cine como elemento plástico, la artista explorará de forma paralela la experimentación matérica y física a través de los cuerpos filmados así como de la propia materialidad de la película, excluyendo toda posibilidad narrativa, dramática e ilusoria de proyección del espectador en el espacio cinematográfico y el espacio privado del creador.

Scaling Qualitative Probability

OpenAIRE

Burgin, Mark

2017-01-01

There are different approaches to qualitative probability, which includes subjective probability. We developed a representation of qualitative probability based on relational systems, which allows modeling uncertainty by probability structures and is more coherent than existing approaches. This setting makes it possible proving that any comparative probability is induced by some probability structure (Theorem 2.1), that classical probability is a probability structure (Theorem 2.2) and that i...

Toward a generalized probability theory: conditional probabilities

International Nuclear Information System (INIS)

Cassinelli, G.

1979-01-01

The main mathematical object of interest in the quantum logic approach to the foundations of quantum mechanics is the orthomodular lattice and a set of probability measures, or states, defined by the lattice. This mathematical structure is studied per se, independently from the intuitive or physical motivation of its definition, as a generalized probability theory. It is thought that the building-up of such a probability theory could eventually throw light on the mathematical structure of Hilbert-space quantum mechanics as a particular concrete model of the generalized theory. (Auth.)

Quantum probability measures and tomographic probability densities

NARCIS (Netherlands)

Amosov, GG; Man'ko, [No Value

2004-01-01

Using a simple relation of the Dirac delta-function to generalized the theta-function, the relationship between the tomographic probability approach and the quantum probability measure approach with the description of quantum states is discussed. The quantum state tomogram expressed in terms of the

COVAL, Compound Probability Distribution for Function of Probability Distribution

International Nuclear Information System (INIS)

Astolfi, M.; Elbaz, J.

1979-01-01

1 - Nature of the physical problem solved: Computation of the probability distribution of a function of variables, given the probability distribution of the variables themselves. 'COVAL' has been applied to reliability analysis of a structure subject to random loads. 2 - Method of solution: Numerical transformation of probability distributions

On Probability Leakage

OpenAIRE

Briggs, William M.

2012-01-01

The probability leakage of model M with respect to evidence E is defined. Probability leakage is a kind of model error. It occurs when M implies that events $y$, which are impossible given E, have positive probability. Leakage does not imply model falsification. Models with probability leakage cannot be calibrated empirically. Regression models, which are ubiquitous in statistical practice, often evince probability leakage.

Efficacy and safety of rilpivirine in treatment-naive, HIV-1-infected patients with hepatitis B virus/hepatitis C virus coinfection enrolled in the Phase III randomized, double-blind ECHO and THRIVE trials.

Science.gov (United States)

Nelson, Mark; Amaya, Gerardo; Clumeck, Nathan; Arns da Cunha, Clovis; Jayaweera, Dushyantha; Junod, Patrice; Li, Taisheng; Tebas, Pablo; Stevens, Marita; Buelens, Annemie; Vanveggel, Simon; Boven, Katia

2012-08-01

The efficacy and hepatic safety of the non-nucleoside reverse transcriptase inhibitors rilpivirine (TMC278) and efavirenz were compared in treatment-naive, HIV-infected adults with concurrent hepatitis B virus (HBV) and/or hepatitis C virus (HCV) infection in the pooled week 48 analysis of the Phase III, double-blind, randomized ECHO (NCT00540449) and THRIVE (NCT00543725) trials. Patients received 25 mg of rilpivirine once daily or 600 mg of efavirenz once daily, plus two nucleoside/nucleotide reverse transcriptase inhibitors. At screening, patients had alanine aminotransferase/aspartate aminotransferase levels ≤5× the upper limit of normal. HBV and HCV status was determined at baseline by HBV surface antigen, HCV antibody and HCV RNA testing. HBV/HCV coinfection status was known for 670 patients in the rilpivirine group and 665 in the efavirenz group. At baseline, 49 rilpivirine and 63 efavirenz patients [112/1335 (8.4%)] were coinfected with either HBV [55/1357 (4.1%)] or HCV [57/1333 (4.3%)]. The safety analysis included all available data, including beyond week 48. Eight patients seroconverted during the study (rilpivirine: five; efavirenz: three). A higher proportion of patients achieved viral load <50 copies/mL (intent to treat, time to loss of virological response) in the subgroup without HBV/HCV coinfection (rilpivirine: 85.0%; efavirenz: 82.6%) than in the coinfected subgroup (rilpivirine: 73.5%; efavirenz: 79.4%) (rilpivirine, P = 0.04 and efavirenz, P = 0.49, Fisher's exact test). The incidence of hepatic adverse events (AEs) was low in both groups in the overall population (rilpivirine: 5.5% versus efavirenz: 6.6%) and was higher in HBV/HCV-coinfected patients than in those not coinfected (26.7% versus 4.1%, respectively). Hepatic AEs were more common and response rates lower in HBV/HCV-coinfected patients treated with rilpivirine or efavirenz than in those who were not coinfected.

Quantum probabilities as Dempster-Shafer probabilities in the lattice of subspaces

International Nuclear Information System (INIS)

Vourdas, A.

2014-01-01

The orthocomplemented modular lattice of subspaces L[H(d)], of a quantum system with d-dimensional Hilbert space H(d), is considered. A generalized additivity relation which holds for Kolmogorov probabilities is violated by quantum probabilities in the full lattice L[H(d)] (it is only valid within the Boolean subalgebras of L[H(d)]). This suggests the use of more general (than Kolmogorov) probability theories, and here the Dempster-Shafer probability theory is adopted. An operator D(H 1 ,H 2 ), which quantifies deviations from Kolmogorov probability theory is introduced, and it is shown to be intimately related to the commutator of the projectors P(H 1 ),P(H 2 ), to the subspaces H 1 , H 2 . As an application, it is shown that the proof of the inequalities of Clauser, Horne, Shimony, and Holt for a system of two spin 1/2 particles is valid for Kolmogorov probabilities, but it is not valid for Dempster-Shafer probabilities. The violation of these inequalities in experiments supports the interpretation of quantum probabilities as Dempster-Shafer probabilities

PROBABILITY SURVEYS , CONDITIONAL PROBABILITIES AND ECOLOGICAL RISK ASSESSMENT

Science.gov (United States)

We show that probability-based environmental resource monitoring programs, such as the U.S. Environmental Protection Agency's (U.S. EPA) Environmental Monitoring and Assessment Program, and conditional probability analysis can serve as a basis for estimating ecological risk over ...

Probability an introduction

CERN Document Server

Goldberg, Samuel

1960-01-01

Excellent basic text covers set theory, probability theory for finite sample spaces, binomial theorem, probability distributions, means, standard deviations, probability function of binomial distribution, more. Includes 360 problems with answers for half.

Probability 1/e

Science.gov (United States)

Koo, Reginald; Jones, Martin L.

2011-01-01

Quite a number of interesting problems in probability feature an event with probability equal to 1/e. This article discusses three such problems and attempts to explain why this probability occurs with such frequency.

Foundations of probability

International Nuclear Information System (INIS)

Fraassen, B.C. van

1979-01-01

The interpretation of probabilities in physical theories are considered, whether quantum or classical. The following points are discussed 1) the functions P(μ, Q) in terms of which states and propositions can be represented, are classical (Kolmogoroff) probabilities, formally speaking, 2) these probabilities are generally interpreted as themselves conditional, and the conditions are mutually incompatible where the observables are maximal and 3) testing of the theory typically takes the form of confronting the expectation values of observable Q calculated with probability measures P(μ, Q) for states μ; hence, of comparing the probabilities P(μ, Q)(E) with the frequencies of occurrence of the corresponding events. It seems that even the interpretation of quantum mechanics, in so far as it concerns what the theory says about the empirical (i.e. actual, observable) phenomena, deals with the confrontation of classical probability measures with observable frequencies. This confrontation is studied. (Auth./C.F.)

TUBERCULOSIS COMO ENFERMEDAD OCUPACIONAL

Science.gov (United States)

Mendoza-Ticona, Alberto

2014-01-01

Existe evidencia suficiente para declarar a la tuberculosis como enfermedad ocupacional en diversos profesionales especialmente entre los trabajadores de salud. En el Perú están normados y reglamentados los derechos laborales inherentes a la tuberculosis como enfermedad ocupacional, como la cobertura por discapacidad temporal o permanente. Sin embargo, estos derechos aún no han sido suficientemente socializados. En este trabajo se presenta información sobre el riesgo de adquirir tuberculosis en el lugar de trabajo, se revisan las evidencias para declarar a la tuberculosis como enfermedad ocupacional en trabajadores de salud y se presenta la legislación peruana vigente al respecto. PMID:22858771

Non-Archimedean Probability

NARCIS (Netherlands)

Benci, Vieri; Horsten, Leon; Wenmackers, Sylvia

We propose an alternative approach to probability theory closely related to the framework of numerosity theory: non-Archimedean probability (NAP). In our approach, unlike in classical probability theory, all subsets of an infinite sample space are measurable and only the empty set gets assigned

Probables casos de alergia endocrínea

Directory of Open Access Journals (Sweden)

Miguel Agustín Solari

1951-01-01

Full Text Available Objeto. Por respecto a una terminología utilizada por autores de indiscutible valor, repetimos en este trabajo la expresión "Alergia Endócrina", pero dejamos constancia de que, en nuestra opinión, no es adecuada para referirse a fenómenos alérgicos en los que las hormones desempeñan el papel de alergenos. En realidad "Alergia Endócrina" corresponde a los fenómenos alérgicos localizados en las glándulas de secreción interna; significa que el órgano de "shock" es alguna parte del sistema endocrino. Cuando un hormón actúa como alergeno debería utilizarse la expresión "alergia hormónica" y si se trata de un hormón que se produce en el mismo organismo a quien enferma correspondería decir "alergia hormonica autógena". Este trabajo es en realidad un estudio hecho sobre probables casos de alergia hormónica autógena; es además una simple "nota previa", casuística, de un trabajo de mayor envergadura en plena evolución. Se presentan aquí tres casos en los que el resultado terapéutico exitoso impone una seria meditación para tratar de comprenderlo; de ahí que este trabajo lleve en el título la palabra "probable", que es prudente y la única que nos hemos permitido utilizar.

Handbook of probability

CERN Document Server

Florescu, Ionut

2013-01-01

THE COMPLETE COLLECTION NECESSARY FOR A CONCRETE UNDERSTANDING OF PROBABILITY Written in a clear, accessible, and comprehensive manner, the Handbook of Probability presents the fundamentals of probability with an emphasis on the balance of theory, application, and methodology. Utilizing basic examples throughout, the handbook expertly transitions between concepts and practice to allow readers an inclusive introduction to the field of probability. The book provides a useful format with self-contained chapters, allowing the reader easy and quick reference. Each chapter includes an introductio

Probability-1

CERN Document Server

Shiryaev, Albert N

2016-01-01

This book contains a systematic treatment of probability from the ground up, starting with intuitive ideas and gradually developing more sophisticated subjects, such as random walks, martingales, Markov chains, the measure-theoretic foundations of probability theory, weak convergence of probability measures, and the central limit theorem. Many examples are discussed in detail, and there are a large number of exercises. The book is accessible to advanced undergraduates and can be used as a text for independent study. To accommodate the greatly expanded material in the third edition of Probability, the book is now divided into two volumes. This first volume contains updated references and substantial revisions of the first three chapters of the second edition. In particular, new material has been added on generating functions, the inclusion-exclusion principle, theorems on monotonic classes (relying on a detailed treatment of “π-λ” systems), and the fundamental theorems of mathematical statistics.

Probability Machines: Consistent Probability Estimation Using Nonparametric Learning Machines

Science.gov (United States)

Malley, J. D.; Kruppa, J.; Dasgupta, A.; Malley, K. G.; Ziegler, A.

2011-01-01

Summary Background Most machine learning approaches only provide a classification for binary responses. However, probabilities are required for risk estimation using individual patient characteristics. It has been shown recently that every statistical learning machine known to be consistent for a nonparametric regression problem is a probability machine that is provably consistent for this estimation problem. Objectives The aim of this paper is to show how random forests and nearest neighbors can be used for consistent estimation of individual probabilities. Methods Two random forest algorithms and two nearest neighbor algorithms are described in detail for estimation of individual probabilities. We discuss the consistency of random forests, nearest neighbors and other learning machines in detail. We conduct a simulation study to illustrate the validity of the methods. We exemplify the algorithms by analyzing two well-known data sets on the diagnosis of appendicitis and the diagnosis of diabetes in Pima Indians. Results Simulations demonstrate the validity of the method. With the real data application, we show the accuracy and practicality of this approach. We provide sample code from R packages in which the probability estimation is already available. This means that all calculations can be performed using existing software. Conclusions Random forest algorithms as well as nearest neighbor approaches are valid machine learning methods for estimating individual probabilities for binary responses. Freely available implementations are available in R and may be used for applications. PMID:21915433

Prevalence of etravirine-associated mutations in clinical samples with resistance to nevirapine and efavirenz.

Science.gov (United States)

Llibre, J M; Santos, J R; Puig, T; Moltó, J; Ruiz, L; Paredes, R; Clotet, B

2008-11-01

To evaluate the expected activity of etravirine in clinical samples, according to mutational patterns associated with decreased virological response (VR). We identified 1586 routine clinical samples with resistance-associated mutations (RAMs) to nevirapine and efavirenz (K103N 60%, Y181C 37%, G190A 27%, V108I 13%). Concerning in vitro identified etravirine mutations, samples with F227C, Y181I, M230L or L100I plus K103N plus Y181C were considered highly resistant. Samples with two RAMs plus Y181C or V179D or K101E or Y188L were considered intermediate. The prevalence of 13 RAMs recently associated with decreased VR to etravirine in the DUET clinical trials was also investigated. Most samples (69%) harboured more than one IAS-USA RAM to first-generation non-nucleoside reverse transcriptase inhibitors (NNRTIs): 42% harboured two RAMs, 21% three RAMs and 6% four or more RAMs. The prevalence of 13 specific etravirine RAMs was V179F 0.12%, G190S 3.9%, Y181V 0.1%, V106I 2.6%, V179D 1.6%, K101P 2.0%, K101E 10.1%, Y181C 36.9%, A98G 5.9%, V90I 6.9%, Y181I 3.6%, G190A 27% and L100I 9.1%. The five RAMs with the most impact on VR (V179F/D, G190S, Y181V and V106I) occurred less often. Overall, 8.2% of the samples had three or more etravirine RAMs and only 1.1% had four or more. In addition, patterns of RAMs previously associated with intermediate etravirine resistance were present in 26.2% of the samples, whereas 4.85% displayed patterns of high-degree resistance. For RAMs associated with decreased VR, etravirine resistance in routine clinical samples was lower than previously reported. High-degree resistance was uncommon, even in patients with resistance to first-generation NNRTIs, whereas low-to-intermediate etravirine resistance was more common.

Janus-faced probability

CERN Document Server

Rocchi, Paolo

2014-01-01

The problem of probability interpretation was long overlooked before exploding in the 20th century, when the frequentist and subjectivist schools formalized two conflicting conceptions of probability. Beyond the radical followers of the two schools, a circle of pluralist thinkers tends to reconcile the opposing concepts. The author uses two theorems in order to prove that the various interpretations of probability do not come into opposition and can be used in different contexts. The goal here is to clarify the multifold nature of probability by means of a purely mathematical approach and to show how philosophical arguments can only serve to deepen actual intellectual contrasts. The book can be considered as one of the most important contributions in the analysis of probability interpretation in the last 10-15 years.

Ruin probabilities

DEFF Research Database (Denmark)

Asmussen, Søren; Albrecher, Hansjörg

The book gives a comprehensive treatment of the classical and modern ruin probability theory. Some of the topics are Lundberg's inequality, the Cramér-Lundberg approximation, exact solutions, other approximations (e.g., for heavy-tailed claim size distributions), finite horizon ruin probabilities......, extensions of the classical compound Poisson model to allow for reserve-dependent premiums, Markov-modulation, periodicity, change of measure techniques, phase-type distributions as a computational vehicle and the connection to other applied probability areas, like queueing theory. In this substantially...... updated and extended second version, new topics include stochastic control, fluctuation theory for Levy processes, Gerber–Shiu functions and dependence....

Interpretations of probability

CERN Document Server

Khrennikov, Andrei

2009-01-01

This is the first fundamental book devoted to non-Kolmogorov probability models. It provides a mathematical theory of negative probabilities, with numerous applications to quantum physics, information theory, complexity, biology and psychology. The book also presents an interesting model of cognitive information reality with flows of information probabilities, describing the process of thinking, social, and psychological phenomena.

Determination of Efavirenz in Human Dried Blood Spots by Reversed-Phase High Performance Liquid Chromatography with UV Detection

Science.gov (United States)

Hoffman, Justin T; Rossi, Steven S; Espina-Quinto, Rowena; Letendre, Scott; Capparelli, Edmund V

2013-01-01

Background Previously published methods for determination of efavirenz (EFV) in human dried blood spots (DBS) employ costly and complex liquid chromatography/mass spectrometry. We describe the validation and evaluation of a simple and inexpensive high-performance liquid chromatography (HPLC) method for EFV quantification in human DBS and dried plasma spots (DPS), using ultraviolet (UV) detection appropriate for resource-limited settings. Methods 100μl of heparinized whole blood or plasma were spotted onto blood collection cards, dried, punched, and eluted. Eluates are injected onto a C-18 reversed phase HPLC column. EFV is separated isocratically using a potassium phosphate and ACN mobile phase. UV detection is at 245nm. Quantitation is by use of external calibration standards. Following validation, the method was evaluated using whole blood and plasma from HIV-positive patients undergoing EFV therapy. Results Mean recovery of drug from dried blood spots is 91.5%. The method is linear over the validated concentration range of 0.3125 – 20.0μg/mL. A good correlation (Spearman r=0.96) between paired plasma and DBS EFV concentrations from the clinical samples was observed, and hematocrit level was not found to be a significant determinant of the EFV DBS level. The mean observed CDBS/Cplasma ratio was 0.68. A good correlation (Spearman r=0.96) between paired plasma and DPS EFV concentrations from the clinical samples was observed. The mean percent deviation of DPS samples from plasma samples is 1.68%. Conclusions Dried whole blood spot or dried plasma spot sampling is well suited for monitoring EFV therapy in resource limited settings, particularly when high sensitivity is not essential. PMID:23503446

Heidegger E A Técnica Moderna Como Perigo E Como Salvação

Directory of Open Access Journals (Sweden)

Robson Costa Cordeiro

2014-04-01

Full Text Available O mundo contemporâneo é marcado por uma compreensão de técnica que se ergue como tal a partir de um sentido próprio e autônomo. Este sentido pode ser caracterizado como um logos que se constitui a partir de sua própria natureza e se manifesta como tecnologia no decorrer da história. Compreender esse sentido e assumi-lo como condição de nossa existência no mundo é comprender a técnica como nossa herança e nosso envio. Nesse sentido, compreender a essência da técnica é fundamental para o mundo contemporâneo, assumindo que, nesse processo, consiste o perigo e a salvação da espécie.

El B-hidroxi-B-metilbutirato (HMB) como suplemento nutricional (I): metabolismo y toxicidad

OpenAIRE

Rafael Manjarrez-Montes-de-Oca

2015-01-01

Introducción: El β-hidroxi-β-metilbutirato (HMB) es un metabolito de la leucina producido a partir del ácido α-cetoisocaproico. El HMB se utiliza como suplemento nutricional en el deporte desde 1997, atribuyéndosele una disminución de la proteólisis muscular. En los últimos años, se han descrito efectos positivos del HMB en diversas patologías, lo cual aumenta su probable utilidad para la mejora de la salud. Objetivos: Los objetivos de la presente revisión son: conocer el metabolismo del HMB,...

Improving Ranking Using Quantum Probability

OpenAIRE

Melucci, Massimo

2011-01-01

The paper shows that ranking information units by quantum probability differs from ranking them by classical probability provided the same data used for parameter estimation. As probability of detection (also known as recall or power) and probability of false alarm (also known as fallout or size) measure the quality of ranking, we point out and show that ranking by quantum probability yields higher probability of detection than ranking by classical probability provided a given probability of ...

Calculating the Probability of Returning a Loan with Binary Probability Models

Directory of Open Access Journals (Sweden)

Julian Vasilev

2014-12-01

Full Text Available The purpose of this article is to give a new approach in calculating the probability of returning a loan. A lot of factors affect the value of the probability. In this article by using statistical and econometric models some influencing factors are proved. The main approach is concerned with applying probit and logit models in loan management institutions. A new aspect of the credit risk analysis is given. Calculating the probability of returning a loan is a difficult task. We assume that specific data fields concerning the contract (month of signing, year of signing, given sum and data fields concerning the borrower of the loan (month of birth, year of birth (age, gender, region, where he/she lives may be independent variables in a binary logistics model with a dependent variable “the probability of returning a loan”. It is proved that the month of signing a contract, the year of signing a contract, the gender and the age of the loan owner do not affect the probability of returning a loan. It is proved that the probability of returning a loan depends on the sum of contract, the remoteness of the loan owner and the month of birth. The probability of returning a loan increases with the increase of the given sum, decreases with the proximity of the customer, increases for people born in the beginning of the year and decreases for people born at the end of the year.

The Effect of Malnutrition on the Pharmacokinetics and Virologic Outcomes of Lopinavir, Efavirenz and Nevirapine in Food Insecure HIV-Infected Children in Tororo, Uganda

Science.gov (United States)

Bartelink, Imke H.; Savic, Rada M.; Dorsey, Grant; Ruel, Theodore; Gingrich, David; Scherpbier, Henriette J.; Capparelli, Edmund; Jullien, Vincent; Young, Sera L.; Achan, Jane; Plenty, Albert; Charlebois, Edwin; Kamya, Moses; Havlir, Diane; Aweeka, Francesca

2014-01-01

Background Malnutrition may impact the pharmacokinetics (PK) of antiretroviral medications and virologic responses in HIV-infected children. We therefore evaluated the PK of nevirapine (NVP), efavirenz (EFV) and lopinavir (LPV) in associations with nutritional status in a cohort of HIV-infected Ugandan children. Methods Sparse dried blood spot (DBS) samples from Ugandan children were used to estimate plasma concentrations. Historical PK data from children from three resource-rich countries (RRC) were utilized to develop the PK models. Results Concentrations in 330 DBS from 163 Ugandan children aged 0.7–7 years were analyzed in reference to plasma PK data (1189 samples) from 204 children from RRC aged 0.5–12 years. Among Ugandan children 48% was malnourished (underweight, thin or stunted). Compared to RRC, Ugandan children exhibited reduced bioavailability of EFV and LPV; 11% (P=0.045) and 18% (P=0.008) respectively. In contrast, NVP bioavailability was 46% higher in Ugandan children (Pmalnutrition on bioavailability. In children receiving NVP, the relation between exposure, malnutrition and outcome turned out to be marginally significant. Further investigations are warranted using more intensive PK measurements and adequate adherence assessements, to further assess causes of virologic failure in Ugandan children. PMID:25742090

On the Possibility of Assigning Probabilities to Singular Cases, or: Probability Is Subjective Too!

Directory of Open Access Journals (Sweden)

Mark R. Crovelli

2009-06-01

Full Text Available Both Ludwig von Mises and Richard von Mises claimed that numerical probability could not be legitimately applied to singular cases. This paper challenges this aspect of the von Mises brothers’ theory of probability. It is argued that their denial that numerical probability could be applied to singular cases was based solely upon Richard von Mises’ exceptionally restrictive definition of probability. This paper challenges Richard von Mises’ definition of probability by arguing that the definition of probability necessarily depends upon whether the world is governed by time-invariant causal laws. It is argued that if the world is governed by time-invariant causal laws, a subjective definition of probability must be adopted. It is further argued that both the nature of human action and the relative frequency method for calculating numerical probabilities both presuppose that the world is indeed governed by time-invariant causal laws. It is finally argued that the subjective definition of probability undercuts the von Mises claim that numerical probability cannot legitimately be applied to singular, non-replicable cases.

Effectiveness and Safety of Generic Fixed-Dose Combination of Tenofovir/Emtricitabine/Efavirenz in HIV-1-Infected Patients in Western India.

Science.gov (United States)

Pujari, Sanjay; Dravid, Ameet; Gupte, Nikhil; Joshix, Kedar; Bele, Vivek

2008-08-20

To assess effectiveness and safety of a generic fixed-dose combination of tenofovir (TDF)/emtricitabine (FTC)/efavirenz (EFV) among HIV-1-infected patients in Western India. Antiretroviral (ARV)-naive and experienced (thymidine analog nucleoside reverse transcriptase inhibitor [tNRTI] replaced by TDF) patients were started on a regimen of 1 TDF/FTC/EFV pill once a day. They were followed clinically on a periodic basis, and viral loads and CD4 counts were measured at 6 and 12 months. Creatinine clearance was calculated at baseline and at 6 months and/or as clinically indicated. Effectiveness was defined as not having to discontinue the regimen due to failure or toxicity. One hundred forty-one patients who started TDF/FTC/EFV before 1 June 2007 were eligible. Of these, 130 (92.2%) and 44 (31.2%) had 6- and 12-months follow-up, respectively. Thirty-five percent of the patients were ARV-naive. Eleven patients discontinued treatment (4 for virologic failure, 1 for grade 3-4 central nervous system disturbances, 4 for grade 3-4 renal toxicity, and 2 for cost). Ninety-six percent of patients were virologically suppressed at 6 months. Frequency of TDF-associated grade 3-4 renal toxicity was 2.8%; however, 3 of these patients had comorbid conditions associated with renal dysfunction. A fixed-dose combination of generic TDF/FTC/EFV is effective in ARV-naive and experienced patients. Although frequency of severe renal toxicity was higher than has been reported in the literature, it was safe in patients with no comorbid renal conditions.

Probability in physics

CERN Document Server

Hemmo, Meir

2012-01-01

What is the role and meaning of probability in physical theory, in particular in two of the most successful theories of our age, quantum physics and statistical mechanics? Laws once conceived as universal and deterministic, such as Newton‘s laws of motion, or the second law of thermodynamics, are replaced in these theories by inherently probabilistic laws. This collection of essays by some of the world‘s foremost experts presents an in-depth analysis of the meaning of probability in contemporary physics. Among the questions addressed are: How are probabilities defined? Are they objective or subjective? What is their  explanatory value? What are the differences between quantum and classical probabilities? The result is an informative and thought-provoking book for the scientifically inquisitive. 

Philosophical theories of probability

CERN Document Server

Gillies, Donald

2000-01-01

The Twentieth Century has seen a dramatic rise in the use of probability and statistics in almost all fields of research. This has stimulated many new philosophical ideas on probability. Philosophical Theories of Probability is the first book to present a clear, comprehensive and systematic account of these various theories and to explain how they relate to one another. Gillies also offers a distinctive version of the propensity theory of probability, and the intersubjective interpretation, which develops the subjective theory.

Probability for statisticians

CERN Document Server

Shorack, Galen R

2017-01-01

This 2nd edition textbook offers a rigorous introduction to measure theoretic probability with particular attention to topics of interest to mathematical statisticians—a textbook for courses in probability for students in mathematical statistics. It is recommended to anyone interested in the probability underlying modern statistics, providing a solid grounding in the probabilistic tools and techniques necessary to do theoretical research in statistics. For the teaching of probability theory to post graduate statistics students, this is one of the most attractive books available. Of particular interest is a presentation of the major central limit theorems via Stein's method either prior to or alternative to a characteristic function presentation. Additionally, there is considerable emphasis placed on the quantile function as well as the distribution function. The bootstrap and trimming are both presented. Martingale coverage includes coverage of censored data martingales. The text includes measure theoretic...

A brief introduction to probability.

Science.gov (United States)

Di Paola, Gioacchino; Bertani, Alessandro; De Monte, Lavinia; Tuzzolino, Fabio

2018-02-01

The theory of probability has been debated for centuries: back in 1600, French mathematics used the rules of probability to place and win bets. Subsequently, the knowledge of probability has significantly evolved and is now an essential tool for statistics. In this paper, the basic theoretical principles of probability will be reviewed, with the aim of facilitating the comprehension of statistical inference. After a brief general introduction on probability, we will review the concept of the "probability distribution" that is a function providing the probabilities of occurrence of different possible outcomes of a categorical or continuous variable. Specific attention will be focused on normal distribution that is the most relevant distribution applied to statistical analysis.

Choice probability generating functions

DEFF Research Database (Denmark)

Fosgerau, Mogens; McFadden, Daniel; Bierlaire, Michel

2013-01-01

This paper considers discrete choice, with choice probabilities coming from maximization of preferences from a random utility field perturbed by additive location shifters (ARUM). Any ARUM can be characterized by a choice-probability generating function (CPGF) whose gradient gives the choice...... probabilities, and every CPGF is consistent with an ARUM. We relate CPGF to multivariate extreme value distributions, and review and extend methods for constructing CPGF for applications. The choice probabilities of any ARUM may be approximated by a cross-nested logit model. The results for ARUM are extended...

Probability of satellite collision

Science.gov (United States)

Mccarter, J. W.

1972-01-01

A method is presented for computing the probability of a collision between a particular artificial earth satellite and any one of the total population of earth satellites. The collision hazard incurred by the proposed modular Space Station is assessed using the technique presented. The results of a parametric study to determine what type of satellite orbits produce the greatest contribution to the total collision probability are presented. Collision probability for the Space Station is given as a function of Space Station altitude and inclination. Collision probability was also parameterized over miss distance and mission duration.

Real analysis and probability

CERN Document Server

Ash, Robert B; Lukacs, E

1972-01-01

Real Analysis and Probability provides the background in real analysis needed for the study of probability. Topics covered range from measure and integration theory to functional analysis and basic concepts of probability. The interplay between measure theory and topology is also discussed, along with conditional probability and expectation, the central limit theorem, and strong laws of large numbers with respect to martingale theory.Comprised of eight chapters, this volume begins with an overview of the basic concepts of the theory of measure and integration, followed by a presentation of var

Probability and Measure

CERN Document Server

Billingsley, Patrick

2012-01-01

Praise for the Third Edition "It is, as far as I'm concerned, among the best books in math ever written....if you are a mathematician and want to have the top reference in probability, this is it." (Amazon.com, January 2006) A complete and comprehensive classic in probability and measure theory Probability and Measure, Anniversary Edition by Patrick Billingsley celebrates the achievements and advancements that have made this book a classic in its field for the past 35 years. Now re-issued in a new style and format, but with the reliable content that the third edition was revered for, this

Experimental Probability in Elementary School

Science.gov (United States)

Andrew, Lane

2009-01-01

Concepts in probability can be more readily understood if students are first exposed to probability via experiment. Performing probability experiments encourages students to develop understandings of probability grounded in real events, as opposed to merely computing answers based on formulae.

A condicionalidade como zona conceitual

Directory of Open Access Journals (Sweden)

Taísa Peres de OLIVEIRA

Full Text Available RESUMO Neste trabalho avaliam-se diferentes padrões de construções condicionais no português a partir dos parâmetros de condicionalidade. O objetivo principal é mostrar como a categoria está internamente organizada não apenas em termos de um núcleo prototípico, mas mostrando como os exemplares mais periféricos se relacionam a ele. As bases teóricas deste trabalho assentam-se sobre concepções funcional-cognitivistas, nos termos de Bybee (2010 e Dancygier (1998, especialmente considerando a relativa instabilidade da gramática e a fluidez da categoria. As reflexões principais apontam a condicionalidade como uma categoria bastante complexa que serve de/como abrigo de múltiplas construções.

Probabilities in physics

CERN Document Server

Hartmann, Stephan

2011-01-01

Many results of modern physics--those of quantum mechanics, for instance--come in a probabilistic guise. But what do probabilistic statements in physics mean? Are probabilities matters of objective fact and part of the furniture of the world, as objectivists think? Or do they only express ignorance or belief, as Bayesians suggest? And how are probabilistic hypotheses justified and supported by empirical evidence? Finally, what does the probabilistic nature of physics imply for our understanding of the world? This volume is the first to provide a philosophical appraisal of probabilities in all of physics. Its main aim is to make sense of probabilistic statements as they occur in the various physical theories and models and to provide a plausible epistemology and metaphysics of probabilities. The essays collected here consider statistical physics, probabilistic modelling, and quantum mechanics, and critically assess the merits and disadvantages of objectivist and subjectivist views of probabilities in these fie...

Probability an introduction

CERN Document Server

Grimmett, Geoffrey

2014-01-01

Probability is an area of mathematics of tremendous contemporary importance across all aspects of human endeavour. This book is a compact account of the basic features of probability and random processes at the level of first and second year mathematics undergraduates and Masters' students in cognate fields. It is suitable for a first course in probability, plus a follow-up course in random processes including Markov chains. A special feature is the authors' attention to rigorous mathematics: not everything is rigorous, but the need for rigour is explained at difficult junctures. The text is enriched by simple exercises, together with problems (with very brief hints) many of which are taken from final examinations at Cambridge and Oxford. The first eight chapters form a course in basic probability, being an account of events, random variables, and distributions - discrete and continuous random variables are treated separately - together with simple versions of the law of large numbers and the central limit th...

Evaluation of nuclear power plant component failure probability and core damage probability using simplified PSA model

International Nuclear Information System (INIS)

Shimada, Yoshio

2000-01-01

It is anticipated that the change of frequency of surveillance tests, preventive maintenance or parts replacement of safety related components may cause the change of component failure probability and result in the change of core damage probability. It is also anticipated that the change is different depending on the initiating event frequency or the component types. This study assessed the change of core damage probability using simplified PSA model capable of calculating core damage probability in a short time period, which is developed by the US NRC to process accident sequence precursors, when various component's failure probability is changed between 0 and 1, or Japanese or American initiating event frequency data are used. As a result of the analysis, (1) It was clarified that frequency of surveillance test, preventive maintenance or parts replacement of motor driven pumps (high pressure injection pumps, residual heat removal pumps, auxiliary feedwater pumps) should be carefully changed, since the core damage probability's change is large, when the base failure probability changes toward increasing direction. (2) Core damage probability change is insensitive to surveillance test frequency change, since the core damage probability change is small, when motor operated valves and turbine driven auxiliary feed water pump failure probability changes around one figure. (3) Core damage probability change is small, when Japanese failure probability data are applied to emergency diesel generator, even if failure probability changes one figure from the base value. On the other hand, when American failure probability data is applied, core damage probability increase is large, even if failure probability changes toward increasing direction. Therefore, when Japanese failure probability data is applied, core damage probability change is insensitive to surveillance tests frequency change etc. (author)

Introduction to probability

CERN Document Server

Freund, John E

1993-01-01

Thorough, lucid coverage of permutations and factorials, probabilities and odds, frequency interpretation, mathematical expectation, decision making, postulates of probability, rule of elimination, binomial distribution, geometric distribution, standard deviation, law of large numbers, and much more. Exercises with some solutions. Summary. Bibliography. Includes 42 black-and-white illustrations. 1973 edition.

El trabajo de campo como proceso. La "etnografía colaborativa" como perspectiva analítica

Directory of Open Access Journals (Sweden)

Leticia Katzer

2011-10-01

Full Text Available El presente artículo contiene una serie de reflexiones elaboradas al poner en diálogo experiencias de campo en el marco de investigaciones individuales; una, con indígenas adscriptos como Huarpes, en el noreste de la provincia de Mendoza; la otra, con indígenas adscriptos como Qom. Éstas reflexiones intentan contribuir a desnaturalizar y visibilizar la complejidad de los contextos de interacción, considerando que abarcan distintas dimensiones y aspectos —tales como posición de los interlocutores en la estructura social, expectativas individuales, experiencias y relaciones previas de los sujetos, y recursos materiales y simbólicos en intermediación—, enfatizando así el carácter situacional y dinámico de esas relaciones de interlocución.A la luz de los actuales debates de la crítica cultural y en un intento por contribuir a los estudios de la Etnografía Colaborativa, el objetivo de este artículo es exponer y describir comparativamente lo que entendemos como performances de campo, situando como objeto de análisis la experiencia etnográfica en sí misma. Entendiendo el trabajo etnográfico como proceso y texto, identificamos tres grandes nudos críticos, reunidos en tres escenas etnográficas, que analizamos como una red multisituada de mediaciones e interrelaciones.

Probably not future prediction using probability and statistical inference

CERN Document Server

Dworsky, Lawrence N

2008-01-01

An engaging, entertaining, and informative introduction to probability and prediction in our everyday lives Although Probably Not deals with probability and statistics, it is not heavily mathematical and is not filled with complex derivations, proofs, and theoretical problem sets. This book unveils the world of statistics through questions such as what is known based upon the information at hand and what can be expected to happen. While learning essential concepts including "the confidence factor" and "random walks," readers will be entertained and intrigued as they move from chapter to chapter. Moreover, the author provides a foundation of basic principles to guide decision making in almost all facets of life including playing games, developing winning business strategies, and managing personal finances. Much of the book is organized around easy-to-follow examples that address common, everyday issues such as: How travel time is affected by congestion, driving speed, and traffic lights Why different gambling ...

Risk Probabilities

DEFF Research Database (Denmark)

Rojas-Nandayapa, Leonardo

Tail probabilities of sums of heavy-tailed random variables are of a major importance in various branches of Applied Probability, such as Risk Theory, Queueing Theory, Financial Management, and are subject to intense research nowadays. To understand their relevance one just needs to think...... analytic expression for the distribution function of a sum of random variables. The presence of heavy-tailed random variables complicates the problem even more. The objective of this dissertation is to provide better approximations by means of sharp asymptotic expressions and Monte Carlo estimators...

Efavirenz

Science.gov (United States)

... along with practicing safer sex and making other life-style changes may decrease the risk of transmitting ( ... exist), loss of touch with reality, or other strange thoughts. Be sure your family knows which symptoms ...

Tolerability of central nervous system symptoms among HIV-1 infected efavirenz users: analysis of patient electronic medical record data.

Science.gov (United States)

Rosenblatt, Lisa; Broder, Michael S; Bentley, Tanya G K; Chang, Eunice; Reddy, Sheila R; Papoyan, Elya; Myers, Joel

2017-08-01

Efavirenz (EFV) is a non-nucleoside reverse transcriptase inhibitor indicated for treatment of HIV-1 infection. Despite concern over EFV tolerability in clinical trials and practice, particularly related to central nervous system (CNS) adverse events, some observational studies have shown high rates of EFV continuation at one year and low rates of CNS-related EFV substitution. The objective of this study was to further examine the real-world rate of CNS-related EFV discontinuation in antiretroviral therapy naïve HIV-1 patients. This retrospective cohort study used a nationally representative electronic medical records database to identify HIV-1 patients ≥12 years old, treated with a 1st-line EFV-based regimen (single or combination antiretroviral tablet) from 1 January 2009 to 30 June 2013. Patients without prior record of EFV use during 6-month baseline (i.e., antiretroviral therapy naïve) were followed 12 months post-medication initiation. CNS-related EFV discontinuation was defined as evidence of a switch to a replacement antiretroviral coupled with record of a CNS symptom within 30 days prior, absent lab evidence of virologic failure. We identified 1742 1st-line EFV patients. Mean age was 48 years, 22.7% were female, and 8.1% had a prior report of CNS symptoms. The first year, overall discontinuation rate among new users of EFV was 16.2%. Ten percent of patients (n = 174) reported a CNS symptom and 1.1% (n = 19) discontinued EFV due to CNS symptoms: insomnia (n = 12), headache (n = 5), impaired concentration (n = 1), and somnolence (n = 1). The frequency of CNS symptoms was similar for patients who discontinued EFV compared to those who did not (10.3 vs. 9.9%; P = .86). Our study found that EFV discontinuation due to CNS symptoms was low, consistent with prior reports.

Outcomes for efavirenz versus nevirapine-containing regimens for treatment of HIV-1 infection: a systematic review and meta-analysis.

Directory of Open Access Journals (Sweden)

Prinitha Pillay

Full Text Available There is conflicting evidence and practice regarding the use of the non-nucleoside reverse transcriptase inhibitors (NNRTI efavirenz (EFV and nevirapine (NVP in first-line antiretroviral therapy (ART.We systematically reviewed virological outcomes in HIV-1 infected, treatment-naive patients on regimens containing EFV versus NVP from randomised trials and observational cohort studies. Data sources include PubMed, Embase, the Cochrane Central Register of Controlled Trials and conference proceedings of the International AIDS Society, Conference on Retroviruses and Opportunistic Infections, between 1996 to May 2013. Relative risks (RR and 95% confidence intervals were synthesized using random-effects meta-analysis. Heterogeneity was assessed using the I(2 statistic, and subgroup analyses performed to assess the potential influence of study design, duration of follow up, location, and tuberculosis treatment. Sensitivity analyses explored the potential influence of different dosages of NVP and different viral load thresholds.Of 5011 citations retrieved, 38 reports of studies comprising 114 391 patients were included for review. EFV was significantly less likely than NVP to lead to virologic failure in both trials (RR 0.85 [0.73-0.99] I(2 = 0% and observational studies (RR 0.65 [0.59-0.71] I(2 = 54%. EFV was more likely to achieve virologic success than NVP, though marginally significant, in both randomised controlled trials (RR 1.04 [1.00-1.08] I(2 = 0% and observational studies (RR 1.06 [1.00-1.12] I(2 = 68%.EFV-based first line ART is significantly less likely to lead to virologic failure compared to NVP-based ART. This finding supports the use of EFV as the preferred NNRTI in first-line treatment regimen for HIV treatment, particularly in resource limited settings.

Quantum processes: probability fluxes, transition probabilities in unit time and vacuum vibrations

International Nuclear Information System (INIS)

Oleinik, V.P.; Arepjev, Ju D.

1989-01-01

Transition probabilities in unit time and probability fluxes are compared in studying the elementary quantum processes -the decay of a bound state under the action of time-varying and constant electric fields. It is shown that the difference between these quantities may be considerable, and so the use of transition probabilities W instead of probability fluxes Π, in calculating the particle fluxes, may lead to serious errors. The quantity W represents the rate of change with time of the population of the energy levels relating partly to the real states and partly to the virtual ones, and it cannot be directly measured in experiment. The vacuum background is shown to be continuously distorted when a perturbation acts on a system. Because of this the viewpoint of an observer on the physical properties of real particles continuously varies with time. This fact is not taken into consideration in the conventional theory of quantum transitions based on using the notion of probability amplitude. As a result, the probability amplitudes lose their physical meaning. All the physical information on quantum dynamics of a system is contained in the mean values of physical quantities. The existence of considerable differences between the quantities W and Π permits one in principle to make a choice of the correct theory of quantum transitions on the basis of experimental data. (author)

Hoy como ayer

OpenAIRE

Rodríguez M.

2010-01-01

Leyendo el artículo titulado “Los medicamentos baratos” de la revista La Farmacia Española, publicada en Madrid el jueves 21 de diciembre de 1893, uno se pregunta cómo puede ser que se reconozca la situación como si fuera de ahora mismo, cómo puede ser que estemos igual que hace más de cien años. Entonces eran los descuentos que se empezaban a extender en las farmacias, francesas sobre todo, y que amenazaban el prestigio profesional de todo el colectivo. Con frases como éstas se define la sit...

Propensity, Probability, and Quantum Theory

Science.gov (United States)

Ballentine, Leslie E.

2016-08-01

Quantum mechanics and probability theory share one peculiarity. Both have well established mathematical formalisms, yet both are subject to controversy about the meaning and interpretation of their basic concepts. Since probability plays a fundamental role in QM, the conceptual problems of one theory can affect the other. We first classify the interpretations of probability into three major classes: (a) inferential probability, (b) ensemble probability, and (c) propensity. Class (a) is the basis of inductive logic; (b) deals with the frequencies of events in repeatable experiments; (c) describes a form of causality that is weaker than determinism. An important, but neglected, paper by P. Humphreys demonstrated that propensity must differ mathematically, as well as conceptually, from probability, but he did not develop a theory of propensity. Such a theory is developed in this paper. Propensity theory shares many, but not all, of the axioms of probability theory. As a consequence, propensity supports the Law of Large Numbers from probability theory, but does not support Bayes theorem. Although there are particular problems within QM to which any of the classes of probability may be applied, it is argued that the intrinsic quantum probabilities (calculated from a state vector or density matrix) are most naturally interpreted as quantum propensities. This does not alter the familiar statistical interpretation of QM. But the interpretation of quantum states as representing knowledge is untenable. Examples show that a density matrix fails to represent knowledge.

Choice Probability Generating Functions

DEFF Research Database (Denmark)

Fosgerau, Mogens; McFadden, Daniel L; Bierlaire, Michel

This paper considers discrete choice, with choice probabilities coming from maximization of preferences from a random utility field perturbed by additive location shifters (ARUM). Any ARUM can be characterized by a choice-probability generating function (CPGF) whose gradient gives the choice...... probabilities, and every CPGF is consistent with an ARUM. We relate CPGF to multivariate extreme value distributions, and review and extend methods for constructing CPGF for applications....

Prediction and probability in sciences

International Nuclear Information System (INIS)

Klein, E.; Sacquin, Y.

1998-01-01

This book reports the 7 presentations made at the third meeting 'physics and fundamental questions' whose theme was probability and prediction. The concept of probability that was invented to apprehend random phenomena has become an important branch of mathematics and its application range spreads from radioactivity to species evolution via cosmology or the management of very weak risks. The notion of probability is the basis of quantum mechanics and then is bound to the very nature of matter. The 7 topics are: - radioactivity and probability, - statistical and quantum fluctuations, - quantum mechanics as a generalized probability theory, - probability and the irrational efficiency of mathematics, - can we foresee the future of the universe?, - chance, eventuality and necessity in biology, - how to manage weak risks? (A.C.)

The quantum probability calculus

International Nuclear Information System (INIS)

Jauch, J.M.

1976-01-01

The Wigner anomaly (1932) for the joint distribution of noncompatible observables is an indication that the classical probability calculus is not applicable for quantum probabilities. It should, therefore, be replaced by another, more general calculus, which is specifically adapted to quantal systems. In this article this calculus is exhibited and its mathematical axioms and the definitions of the basic concepts such as probability field, random variable, and expectation values are given. (B.R.H)

Excluding joint probabilities from quantum theory

Science.gov (United States)

Allahverdyan, Armen E.; Danageozian, Arshag

2018-03-01

Quantum theory does not provide a unique definition for the joint probability of two noncommuting observables, which is the next important question after the Born's probability for a single observable. Instead, various definitions were suggested, e.g., via quasiprobabilities or via hidden-variable theories. After reviewing open issues of the joint probability, we relate it to quantum imprecise probabilities, which are noncontextual and are consistent with all constraints expected from a quantum probability. We study two noncommuting observables in a two-dimensional Hilbert space and show that there is no precise joint probability that applies for any quantum state and is consistent with imprecise probabilities. This contrasts with theorems by Bell and Kochen-Specker that exclude joint probabilities for more than two noncommuting observables, in Hilbert space with dimension larger than two. If measurement contexts are included into the definition, joint probabilities are not excluded anymore, but they are still constrained by imprecise probabilities.

Linear positivity and virtual probability

International Nuclear Information System (INIS)

Hartle, James B.

2004-01-01

We investigate the quantum theory of closed systems based on the linear positivity decoherence condition of Goldstein and Page. The objective of any quantum theory of a closed system, most generally the universe, is the prediction of probabilities for the individual members of sets of alternative coarse-grained histories of the system. Quantum interference between members of a set of alternative histories is an obstacle to assigning probabilities that are consistent with the rules of probability theory. A quantum theory of closed systems therefore requires two elements: (1) a condition specifying which sets of histories may be assigned probabilities and (2) a rule for those probabilities. The linear positivity condition of Goldstein and Page is the weakest of the general conditions proposed so far. Its general properties relating to exact probability sum rules, time neutrality, and conservation laws are explored. Its inconsistency with the usual notion of independent subsystems in quantum mechanics is reviewed. Its relation to the stronger condition of medium decoherence necessary for classicality is discussed. The linear positivity of histories in a number of simple model systems is investigated with the aim of exhibiting linearly positive sets of histories that are not decoherent. The utility of extending the notion of probability to include values outside the range of 0-1 is described. Alternatives with such virtual probabilities cannot be measured or recorded, but can be used in the intermediate steps of calculations of real probabilities. Extended probabilities give a simple and general way of formulating quantum theory. The various decoherence conditions are compared in terms of their utility for characterizing classicality and the role they might play in further generalizations of quantum mechanics

The pleasures of probability

CERN Document Server

Isaac, Richard

1995-01-01

The ideas of probability are all around us. Lotteries, casino gambling, the al­ most non-stop polling which seems to mold public policy more and more­ these are a few of the areas where principles of probability impinge in a direct way on the lives and fortunes of the general public. At a more re­ moved level there is modern science which uses probability and its offshoots like statistics and the theory of random processes to build mathematical descriptions of the real world. In fact, twentieth-century physics, in embrac­ ing quantum mechanics, has a world view that is at its core probabilistic in nature, contrary to the deterministic one of classical physics. In addition to all this muscular evidence of the importance of probability ideas it should also be said that probability can be lots of fun. It is a subject where you can start thinking about amusing, interesting, and often difficult problems with very little mathematical background. In this book, I wanted to introduce a reader with at least a fairl...

Probable Inference and Quantum Mechanics

International Nuclear Information System (INIS)

Grandy, W. T. Jr.

2009-01-01

In its current very successful interpretation the quantum theory is fundamentally statistical in nature. Although commonly viewed as a probability amplitude whose (complex) square is a probability, the wavefunction or state vector continues to defy consensus as to its exact meaning, primarily because it is not a physical observable. Rather than approach this problem directly, it is suggested that it is first necessary to clarify the precise role of probability theory in quantum mechanics, either as applied to, or as an intrinsic part of the quantum theory. When all is said and done the unsurprising conclusion is that quantum mechanics does not constitute a logic and probability unto itself, but adheres to the long-established rules of classical probability theory while providing a means within itself for calculating the relevant probabilities. In addition, the wavefunction is seen to be a description of the quantum state assigned by an observer based on definite information, such that the same state must be assigned by any other observer based on the same information, in much the same way that probabilities are assigned.

Psychophysics of the probability weighting function

Science.gov (United States)

Takahashi, Taiki

2011-03-01

A probability weighting function w(p) for an objective probability p in decision under risk plays a pivotal role in Kahneman-Tversky prospect theory. Although recent studies in econophysics and neuroeconomics widely utilized probability weighting functions, psychophysical foundations of the probability weighting functions have been unknown. Notably, a behavioral economist Prelec (1998) [4] axiomatically derived the probability weighting function w(p)=exp(-() (01e)=1e,w(1)=1), which has extensively been studied in behavioral neuroeconomics. The present study utilizes psychophysical theory to derive Prelec's probability weighting function from psychophysical laws of perceived waiting time in probabilistic choices. Also, the relations between the parameters in the probability weighting function and the probability discounting function in behavioral psychology are derived. Future directions in the application of the psychophysical theory of the probability weighting function in econophysics and neuroeconomics are discussed.

Probability concepts in quality risk management.

Science.gov (United States)

Claycamp, H Gregg

2012-01-01

Essentially any concept of risk is built on fundamental concepts of chance, likelihood, or probability. Although risk is generally a probability of loss of something of value, given that a risk-generating event will occur or has occurred, it is ironic that the quality risk management literature and guidelines on quality risk management tools are relatively silent on the meaning and uses of "probability." The probability concept is typically applied by risk managers as a combination of frequency-based calculation and a "degree of belief" meaning of probability. Probability as a concept that is crucial for understanding and managing risk is discussed through examples from the most general, scenario-defining and ranking tools that use probability implicitly to more specific probabilistic tools in risk management. A rich history of probability in risk management applied to other fields suggests that high-quality risk management decisions benefit from the implementation of more thoughtful probability concepts in both risk modeling and risk management. Essentially any concept of risk is built on fundamental concepts of chance, likelihood, or probability. Although "risk" generally describes a probability of loss of something of value, given that a risk-generating event will occur or has occurred, it is ironic that the quality risk management literature and guidelines on quality risk management methodologies and respective tools focus on managing severity but are relatively silent on the in-depth meaning and uses of "probability." Pharmaceutical manufacturers are expanding their use of quality risk management to identify and manage risks to the patient that might occur in phases of the pharmaceutical life cycle from drug development to manufacture, marketing to product discontinuation. A probability concept is typically applied by risk managers as a combination of data-based measures of probability and a subjective "degree of belief" meaning of probability. Probability as

Genotypic evaluation of etravirine sensitivity of clinical human immunodeficiency virus type 1 (HIV-1) isolates carrying resistance mutations to nevirapine and efavirenz.

Science.gov (United States)

Oumar, A A; Jnaoui, K; Kabamba-Mukadi, B; Yombi, J C; Vandercam, B; Goubau, P; Ruelle, J

2010-01-01

Etravirine is a second-generation non-nucleoside reverse transcriptase inhibitor (NNRTI) with a pattern of resistance mutations quite distinct from the current NNRTIs. We collected all routine samples of HIV-1 patients followed in the AIDS reference laboratory of UCLouvain (in 2006 and 2007) carrying resistance-associated mutations to nevirapine (NVP) or efavirenz (EFV). The sensitivity to Etravirine was estimated using three different drug resistance algorithms: ANRS (July 2008), IAS (December 2008) and Stanford (November 2008). We also verified whether the mutations described as resistance mutations are not due to virus polymorphisms by the study of 58 genotypes of NNRTI-naive patients. Sixty one samples harboured resistance to NVP and EFV: 41/61 had at least one resistance mutation to Etravirine according to ANRS-IAS algorithms; 42/61 samples had at least one resistance mutation to Etravirine according to the Stanford algorithm. 48 and 53 cases were fully sensitive to Etravirine according to ANRS-IAS and Stanford algorithms, respectively. Three cases harboured more than three mutations and presented a pattern of high-degree resistance to Etravirine according to ANRS-IAS algorithm, while one case harboured more than three mutations and presented high degree resistance to Etravirine according to the Stanford algorithm. The V1061 and V179D mutations were more frequent in the ARV-naive group than in the NNRTI-experienced one. According to the currently available algorithms, Etravirine can still be used in the majority of patients with virus showing resistance to NVP and/or EFV, if a combination of other active drugs is included.

The perception of probability.

Science.gov (United States)

Gallistel, C R; Krishan, Monika; Liu, Ye; Miller, Reilly; Latham, Peter E

2014-01-01

We present a computational model to explain the results from experiments in which subjects estimate the hidden probability parameter of a stepwise nonstationary Bernoulli process outcome by outcome. The model captures the following results qualitatively and quantitatively, with only 2 free parameters: (a) Subjects do not update their estimate after each outcome; they step from one estimate to another at irregular intervals. (b) The joint distribution of step widths and heights cannot be explained on the assumption that a threshold amount of change must be exceeded in order for them to indicate a change in their perception. (c) The mapping of observed probability to the median perceived probability is the identity function over the full range of probabilities. (d) Precision (how close estimates are to the best possible estimate) is good and constant over the full range. (e) Subjects quickly detect substantial changes in the hidden probability parameter. (f) The perceived probability sometimes changes dramatically from one observation to the next. (g) Subjects sometimes have second thoughts about a previous change perception, after observing further outcomes. (h) The frequency with which they perceive changes moves in the direction of the true frequency over sessions. (Explaining this finding requires 2 additional parametric assumptions.) The model treats the perception of the current probability as a by-product of the construction of a compact encoding of the experienced sequence in terms of its change points. It illustrates the why and the how of intermittent Bayesian belief updating and retrospective revision in simple perception. It suggests a reinterpretation of findings in the recent literature on the neurobiology of decision making. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

Introduction to probability with R

CERN Document Server

Baclawski, Kenneth

2008-01-01

FOREWORD PREFACE Sets, Events, and Probability The Algebra of Sets The Bernoulli Sample Space The Algebra of Multisets The Concept of Probability Properties of Probability Measures Independent Events The Bernoulli Process The R Language Finite Processes The Basic Models Counting Rules Computing Factorials The Second Rule of Counting Computing Probabilities Discrete Random Variables The Bernoulli Process: Tossing a Coin The Bernoulli Process: Random Walk Independence and Joint Distributions Expectations The Inclusion-Exclusion Principle General Random Variable

Applied probability and stochastic processes

CERN Document Server

Sumita, Ushio

1999-01-01

Applied Probability and Stochastic Processes is an edited work written in honor of Julien Keilson. This volume has attracted a host of scholars in applied probability, who have made major contributions to the field, and have written survey and state-of-the-art papers on a variety of applied probability topics, including, but not limited to: perturbation method, time reversible Markov chains, Poisson processes, Brownian techniques, Bayesian probability, optimal quality control, Markov decision processes, random matrices, queueing theory and a variety of applications of stochastic processes. The book has a mixture of theoretical, algorithmic, and application chapters providing examples of the cutting-edge work that Professor Keilson has done or influenced over the course of his highly-productive and energetic career in applied probability and stochastic processes. The book will be of interest to academic researchers, students, and industrial practitioners who seek to use the mathematics of applied probability i...

Las leyendas regionales como intangibles territoriales

Directory of Open Access Journals (Sweden)

Eloy Martos Núñez

2015-01-01

Full Text Available El artículo examina el concepto de leyenda como intangible territorial en diversas escalas, desde la local a la regional o nacional, y su relación con la construcción de mitos étnicos y la emergencia de tradiciones translocales. Para ello, se revisan la metodología de los estudios corográficos y las nociones de ecotipo y de paisaje cultural, así como la etnografía de los territorios simbólicos a la luz de conceptos como el clásico «témenos» y modernos como el «mytho-moteur» (Abadal, 1958. Se aplican estudios de casos que evidencian cómo es el Imaginario, en interacción con factores geohistóricos del lugar, el que a menudo acota y perimetrea un territorio a través de cauces como la fabulación legendaria y los ritos paralitúgicos, como procesiones o peregrinaciones. La conclusión es que las leyendas y los arquetipos de origen étnico y genealógico reescriben tradiciones que crean identidades y se pueden proyectar en ámbitos diferentes de la vida política o recreativa, con perfiles igualmente diferentes.

Systematic Approach for the Formulation and Optimization of Solid Lipid Nanoparticles of Efavirenz by High Pressure Homogenization Using Design of Experiments for Brain Targeting and Enhanced Bioavailability

Science.gov (United States)

Gupta, Shweta; Kesarla, Rajesh; Chotai, Narendra; Misra, Ambikanandan

2017-01-01

The nonnucleoside reverse transcriptase inhibitors, used for the treatment of HIV infections, are reported to have low bioavailability pertaining to high first-pass metabolism, high protein binding, and enzymatic metabolism. They also show low permeability across blood brain barrier. The CNS is reported to be the most important HIV reservoir site. In the present study, solid lipid nanoparticles of efavirenz were prepared with the objective of providing increased permeability and protection of drug due to biocompatible lipidic content and nanoscale size and thus developing formulation having potential for enhanced bioavailability and brain targeting. Solid lipid nanoparticles were prepared by high pressure homogenization technique using a systematic approach of design of experiments (DoE) and evaluated for particle size, polydispersity index, zeta potential, and entrapment efficiency. Particles of average size 108.5 nm having PDI of 0.172 with 64.9% entrapment efficiency were produced. Zeta potential was found to be −21.2 mV and the formulation was found stable. The in-vivo pharmacokinetic studies revealed increased concentration of the drug in brain, as desired, when administered through intranasal route indicating its potential for an attempt towards complete eradication of HIV and cure of HIV-infected patients. PMID:28243600

Changes in Liver Steatosis After Switching From Efavirenz to Raltegravir Among Human Immunodeficiency Virus-Infected Patients With Nonalcoholic Fatty Liver Disease.

Science.gov (United States)

Macías, Juan; Mancebo, María; Merino, Dolores; Téllez, Francisco; Montes-Ramírez, M Luisa; Pulido, Federico; Rivero-Juárez, Antonio; Raffo, Miguel; Pérez-Pérez, Montserrat; Merchante, Nicolás; Cotarelo, Manuel; Pineda, Juan A

2017-09-15

Antiretroviral drugs with a lower potential to induce hepatic steatosis in human immunodeficiency virus (HIV) infection need to be identified. We compared the effect of switching efavirenz (EFV) to raltegravir (RAL) on hepatic steatosis among HIV-infected patients with nonalcoholic fatty liver disease (NAFLD) receiving EFV plus 2 nucleoside analogues. HIV-infected patients on EFV plus tenofovir/emtricitabine or abacavir/lamivudine with NAFLD were randomized 1:1 to switch from EFV to RAL (400 mg twice daily), maintaining nucleoside analogues unchanged, or to continue with EFV plus 2 nucleoside analogues. At baseline, eligible patients should show controlled attenuation parameter (CAP) values ≥238 dB/m. Changes in hepatic steatosis at 48 weeks of follow-up over baseline levels were measured by CAP. Overall, 39 patients were included, and 19 of them were randomized to switch to RAL. At week 48, median CAP for the RAL group was 250 (Q1-Q3, 221-277) dB/m and 286 (Q1-Q3, 269-314) dB/m for the EFV group (P = .035). The median decrease in CAP values was -20 (Q1-Q3, -67 to 15) dB/m for the RAL arm and 30 (Q1-Q3, -17 to 49) dB/m for the EFV group (P = .011). CAP values hepatic steatosis, as measured by CAP, compared with those continuing with EFV. In addition, the proportion of patients without significant hepatic steatosis after 48 weeks was greater for those who switched to RAL. NCT01900015. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.

Collision Probability Analysis

DEFF Research Database (Denmark)

Hansen, Peter Friis; Pedersen, Preben Terndrup

1998-01-01

It is the purpose of this report to apply a rational model for prediction of ship-ship collision probabilities as function of the ship and the crew characteristics and the navigational environment for MS Dextra sailing on a route between Cadiz and the Canary Islands.The most important ship and crew...... characteristics are: ship speed, ship manoeuvrability, the layout of the navigational bridge, the radar system, the number and the training of navigators, the presence of a look out etc. The main parameters affecting the navigational environment are ship traffic density, probability distributions of wind speeds...... probability, i.e. a study of the navigator's role in resolving critical situations, a causation factor is derived as a second step.The report documents the first step in a probabilistic collision damage analysis. Future work will inlcude calculation of energy released for crushing of structures giving...

Irreversibility and conditional probability

International Nuclear Information System (INIS)

Stuart, C.I.J.M.

1989-01-01

The mathematical entropy - unlike physical entropy - is simply a measure of uniformity for probability distributions in general. So understood, conditional entropies have the same logical structure as conditional probabilities. If, as is sometimes supposed, conditional probabilities are time-reversible, then so are conditional entropies and, paradoxically, both then share this symmetry with physical equations of motion. The paradox is, of course that probabilities yield a direction to time both in statistical mechanics and quantum mechanics, while the equations of motion do not. The supposed time-reversibility of both conditionals seems also to involve a form of retrocausality that is related to, but possibly not the same as, that described by Costa de Beaurgard. The retrocausality is paradoxically at odds with the generally presumed irreversibility of the quantum mechanical measurement process. Further paradox emerges if the supposed time-reversibility of the conditionals is linked with the idea that the thermodynamic entropy is the same thing as 'missing information' since this confounds the thermodynamic and mathematical entropies. However, it is shown that irreversibility is a formal consequence of conditional entropies and, hence, of conditional probabilities also. 8 refs. (Author)

Introduction to probability with Mathematica

CERN Document Server

Hastings, Kevin J

2009-01-01

Discrete ProbabilityThe Cast of Characters Properties of Probability Simulation Random SamplingConditional ProbabilityIndependenceDiscrete DistributionsDiscrete Random Variables, Distributions, and ExpectationsBernoulli and Binomial Random VariablesGeometric and Negative Binomial Random Variables Poisson DistributionJoint, Marginal, and Conditional Distributions More on ExpectationContinuous ProbabilityFrom the Finite to the (Very) Infinite Continuous Random Variables and DistributionsContinuous ExpectationContinuous DistributionsThe Normal Distribution Bivariate Normal DistributionNew Random Variables from OldOrder Statistics Gamma DistributionsChi-Square, Student's t, and F-DistributionsTransformations of Normal Random VariablesAsymptotic TheoryStrong and Weak Laws of Large Numbers Central Limit TheoremStochastic Processes and ApplicationsMarkov ChainsPoisson Processes QueuesBrownian MotionFinancial MathematicsAppendixIntroduction to Mathematica Glossary of Mathematica Commands for Probability Short Answers...

Failure probability under parameter uncertainty.

Science.gov (United States)

Gerrard, R; Tsanakas, A

2011-05-01

In many problems of risk analysis, failure is equivalent to the event of a random risk factor exceeding a given threshold. Failure probabilities can be controlled if a decisionmaker is able to set the threshold at an appropriate level. This abstract situation applies, for example, to environmental risks with infrastructure controls; to supply chain risks with inventory controls; and to insurance solvency risks with capital controls. However, uncertainty around the distribution of the risk factor implies that parameter error will be present and the measures taken to control failure probabilities may not be effective. We show that parameter uncertainty increases the probability (understood as expected frequency) of failures. For a large class of loss distributions, arising from increasing transformations of location-scale families (including the log-normal, Weibull, and Pareto distributions), the article shows that failure probabilities can be exactly calculated, as they are independent of the true (but unknown) parameters. Hence it is possible to obtain an explicit measure of the effect of parameter uncertainty on failure probability. Failure probability can be controlled in two different ways: (1) by reducing the nominal required failure probability, depending on the size of the available data set, and (2) by modifying of the distribution itself that is used to calculate the risk control. Approach (1) corresponds to a frequentist/regulatory view of probability, while approach (2) is consistent with a Bayesian/personalistic view. We furthermore show that the two approaches are consistent in achieving the required failure probability. Finally, we briefly discuss the effects of data pooling and its systemic risk implications. © 2010 Society for Risk Analysis.

Conditional Probability Modulates Visual Search Efficiency

Directory of Open Access Journals (Sweden)

Bryan eCort

2013-10-01

Full Text Available We investigated the effects of probability on visual search. Previous work has shown that people can utilize spatial and sequential probability information to improve target detection. We hypothesized that performance improvements from probability information would extend to the efficiency of visual search. Our task was a simple visual search in which the target was always present among a field of distractors, and could take one of two colors. The absolute probability of the target being either color was 0.5; however, the conditional probability – the likelihood of a particular color given a particular combination of two cues – varied from 0.1 to 0.9. We found that participants searched more efficiently for high conditional probability targets and less efficiently for low conditional probability targets, but only when they were explicitly informed of the probability relationship between cues and target color.

La razonabilidad como virtud

OpenAIRE

Muñoz Oliveira, Luis Humberto

2008-01-01

Consultable des del TDX Títol obtingut de la portada digitalitzada Esta tesis doctoral explora la idea de que la razonabilidad es una virtud fundamental para que las sociedades plurales puedan convertirse en, o mantenerse como, un sistema de cooperación donde la justicia sea posible. La hipótesis central es que la razonabilidad como virtud es una manera de ser tolerante de forma solidaria, es entender al conciudadano, escucharlo, saber que juntos acordaron las reglas de cooperación y ac...

Josep Beuys : el arte como creencia y como salvación

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María López Ruido

1995-01-01

Full Text Available Joseph Beuys, nacido en Cléveris (Renania del Norte-Westfalia en 1921 y faliecido en Dusseldorf en 1986, posee una obra madura casi desde un primer momento. Superficialmente podríamos verla como el canto a sí mismo de un gran narcisista, donde sus experiencias y su persona son los grandes protagonistas. En una lectura más profunda, estos hechos personales no son más que el medio para ir más allá del yo y dar lugar a una creación plástica de trascendencia social. Tras la 2- Guerra Mundial, en la que lucha como piloto de la Luftwaffe, estudia en la Academia de Bellas Artes de Dusseldorf. Será a partir de los años 60 cuando encontremos al auténtico Beuys, escultor objetual e instalador, el creador de la plástica social, y desde sus contactos con Fluxus en 1962, el Beuys accionista. En los 70, se nos presenta el artista más claramente politizado. La educación, la incidencia social del arte, el arte como «tercera vía o vía alternativa» entre socialismo y capitalismo, la ecología serán sus materiales de trabajo.

La universidad como organización

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Luis Aurelio Ordoñez Burbano

2001-07-01

Full Text Available El presente artículo versa sobre la unviersidad como organización y tiene como objetivo hacer una reflexión sobre la misión de la universidad colombiana en el marco de diversos entornos. Como punto de partida, se propone una precisión sobre la misión de la universidad moderna y la investigación, a diferencia de la universidad colonial y decimonónica limitada a la divulgación de conocimientos preexistentes.

Present trophic conditions of the Como and Lecco basins of lake Como; Attuali condizioni trofiche dei bacini di Como e Lecco del Lario

Energy Technology Data Exchange (ETDEWEB)

Mosello, R.; Brizzio, M.C. [Consiglio Nazionale delle Ricerche, Verbania (Italy). Ist. Italiano di Idrobiologia; Garibaldi, L. [Milan Univ. La Bicocca, Milan (Italy). Dipt. di Scienze dell' Ambiente; Buzzi, P. [Azienda Sanitaria Locale, Lecco (Italy). Unita' Operativa Fisica e Tutela Ambiente; Colzani, L.; Pizzotti, E. [Azienda Sanitaria Locale, Como (Italy). Unita' Operativa Chimica; Mocellin, D. [Azienda Sanitaria Locale, Sondrio (Italy). Unita' Operativa Chimica

1999-12-01

Monthly measurements of temperature, water chemistry and phytoplankton performed from september 1997 to August 1998 in lake basins close the towns of Como and Lecco (Italy) are presented and discussed. Chemical variables show a high trophic level in both stations, more pronounced in the Como station due to unfavourable hydrological conditions and to urban and industrial sources of pollution, which show the predominance of Oscillatoria rubescens. [Italian] Il presente lavoro riporta i risultati di un'indagine condotta con campionamenti mensili dal settembre 1997 all'agosto 1998 nei bacini di Como e Lecco. Le variabili chimiche analizzate evidenziano, per entrambe le stazioni considerate, un elevato livello di trofia piu' pronunciato nella stazione di Come a causa di sfavorevoli condizioni idrologiche e per la presenza di sorgenti di inquinamento urbano e industriale, confermato dalla predominanza di Oscillatoria rubescens.

El Derecho como argumentación

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Atienza, Manuel

1999-11-01

Full Text Available Not available

Frente a las concepciones del Derecho como norma, como hecho o como valor (que caracterizan, respectivamente, al norrnativismo, al realismo jurídico y al iusnaturalismo, se propone aquí un cuarto enfoque que consiste en ver el Derecho como argumentación (y que cohra especial relevancia en las sociedades democráticas. Sin embargo, no hay una única forma de entender la argumentación jurídica. Aunque conectadas entre sí, en el trabajo se distinguen tres concepciones: la formal, la material y la pragmática o dialéctica; muchas cuestiones que se plantean en el ámbito de la teoría de la argumentación jurídica pueden resolverse -o aclararse- teniendo en cuenta esa triple perspectiva.

Terapia antiviral para VIH-SIDA

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Alicia Tarinas Reyes

2000-12-01

Full Text Available En los últimos años, muchos agentes antivirales nuevos han sido incorporados a la quimioterapéutica. En esta revisión se resumen tanto los fármacos establecidos de años atrás como los nuevos medicamentos desarrollados para el tratamiento de individuos infectados por VIH. El AZT fue el primero aprobado en marzo de 1987, le siguió el ddl (1991, ddC (1992, d4T (1994, 3TC (1995. Luego fue aprobado el primer inhibidor de proteasa, saquinavir en diciembre de 1995, seguido de ritonavir (1996, indinavir (1996, nelfinavir (1997; además de otros inhibidores de la reverso transcriptasa como nevirapine (1996, delavirdine (1997, efavirenz (1998, entre otros. En estos momentos se siguen buscando y desarrollando nuevas terapias alternativas para esta afección. En este trabajo se exponen algunas de las características de dichos medicamentos, como son: mecanismos de acción (sobre qué enzima actúa cada uno y cómo lo hacen, el ciclo viral, dosificación, incompatibilidades y reacciones adversas.During the last years many new antiviral agents have been incorporated to the chemotherapeutics. The pharmaceuticals established years ago as well as the new ones developed to treat HIV infected individuals are included in this review. The AZT was the first approved in March, 1987, followed by ddl (1991, ddc (1992, d4t (1994, and 3TC (1995. Later, the first protease inhibitor, saquinovir, was approved in December, 1995, followed by ritonavir (1996, indinavir (1996, and nelfinavir (1997; in addition to other inhibitors of the reverse transcriptase as neviparine (1996, delavirdine (1997, and efavirenz (1998, among others. At present new alternative therapies for this affection are being searched and developed. Some of the characteristics of these dugs, such as: action mechanisms (on which enzime each of them act and how they do it, viral cycle, dosage, incompatibilites and adverse reactions are dealt with in this paper.

A first course in probability

CERN Document Server

Ross, Sheldon

2014-01-01

A First Course in Probability, Ninth Edition, features clear and intuitive explanations of the mathematics of probability theory, outstanding problem sets, and a variety of diverse examples and applications. This book is ideal for an upper-level undergraduate or graduate level introduction to probability for math, science, engineering and business students. It assumes a background in elementary calculus.

Estimating Subjective Probabilities

DEFF Research Database (Denmark)

Andersen, Steffen; Fountain, John; Harrison, Glenn W.

2014-01-01

either construct elicitation mechanisms that control for risk aversion, or construct elicitation mechanisms which undertake 'calibrating adjustments' to elicited reports. We illustrate how the joint estimation of risk attitudes and subjective probabilities can provide the calibration adjustments...... that theory calls for. We illustrate this approach using data from a controlled experiment with real monetary consequences to the subjects. This allows the observer to make inferences about the latent subjective probability, under virtually any well-specified model of choice under subjective risk, while still...

La sabidur?a como competencia gerencial

OpenAIRE

Pinzon-Barrios, Ana-Maria; Cort?s Zapata, Gabriela

2012-01-01

Aunque el concepto de sabidur?a ha sido ampliamente estudiado por expertos de ?reas como la filosof?a, la religi?n y la psicolog?a, a?n enfrenta limitaciones en cuanto a su definici?n y evaluaci?n. Por esto, el presente trabajo tiene como objetivo, formular una definici?n del concepto de sabidur?a que permita realizar una propuesta de evaluaci?n del concepto como competencia en los gerentes. Para esto, se realiz? un an?lisis documental de tipo cualitativo. De esta manera, se analizaron divers...

Probability and Bayesian statistics

CERN Document Server

1987-01-01

This book contains selected and refereed contributions to the "Inter­ national Symposium on Probability and Bayesian Statistics" which was orga­ nized to celebrate the 80th birthday of Professor Bruno de Finetti at his birthplace Innsbruck in Austria. Since Professor de Finetti died in 1985 the symposium was dedicated to the memory of Bruno de Finetti and took place at Igls near Innsbruck from 23 to 26 September 1986. Some of the pa­ pers are published especially by the relationship to Bruno de Finetti's scientific work. The evolution of stochastics shows growing importance of probability as coherent assessment of numerical values as degrees of believe in certain events. This is the basis for Bayesian inference in the sense of modern statistics. The contributions in this volume cover a broad spectrum ranging from foundations of probability across psychological aspects of formulating sub­ jective probability statements, abstract measure theoretical considerations, contributions to theoretical statistics an...

Market-implied risk-neutral probabilities, actual probabilities, credit risk and news

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Shashidhar Murthy

2011-09-01

Full Text Available Motivated by the credit crisis, this paper investigates links between risk-neutral probabilities of default implied by markets (e.g. from yield spreads and their actual counterparts (e.g. from ratings. It discusses differences between the two and clarifies underlying economic intuition using simple representations of credit risk pricing. Observed large differences across bonds in the ratio of the two probabilities are shown to imply that apparently safer securities can be more sensitive to news.

Aprendizagem como/na prática

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Jean Lave

2015-12-01

Full Text Available ResumoEste artigo considera como o estudo da cultura e da aprendizagem pode ser de particular relevância para o campo da antropologia sociocultural em geral. O termo mais importante na expressão “cultura & aprendizagem” talvez seja o logograma “&” – ou seja, coloca-se a questão sobre o que conecta cultura e aprendizagem, perguntando-se como esses termos estão relacionados. Como devemos compreender cultura e aprendizagem como instâncias produtoras delas próprias, e uma da outra, na prática? Recalibrando em termos relacionais, podemos dizer que não é possível abordar a “aprendizagem” ou “cultura e aprendizagem” sem o seu emaranhamento na vida político-econômica, nas lutas e disputas históricas, em suas coerências e incoerências, e na produção relacional e histórica da vida cotidiana. Através das lentes da teoria da prática social, os estudos etnográficos sobre aprendizagem na prática oferecem diferentes entendimentos sobre como certa vida e certas disputas e incoerências são produzidas.

Spatial probability aids visual stimulus discrimination

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Michael Druker

2010-08-01

Full Text Available We investigated whether the statistical predictability of a target's location would influence how quickly and accurately it was classified. Recent results have suggested that spatial probability can be a cue for the allocation of attention in visual search. One explanation for probability cuing is spatial repetition priming. In our two experiments we used probability distributions that were continuous across the display rather than relying on a few arbitrary screen locations. This produced fewer spatial repeats and allowed us to dissociate the effect of a high probability location from that of short-term spatial repetition. The task required participants to quickly judge the color of a single dot presented on a computer screen. In Experiment 1, targets were more probable in an off-center hotspot of high probability that gradually declined to a background rate. Targets garnered faster responses if they were near earlier target locations (priming and if they were near the high probability hotspot (probability cuing. In Experiment 2, target locations were chosen on three concentric circles around fixation. One circle contained 80% of targets. The value of this ring distribution is that it allowed for a spatially restricted high probability zone in which sequentially repeated trials were not likely to be physically close. Participant performance was sensitive to the high-probability circle in addition to the expected effects of eccentricity and the distance to recent targets. These two experiments suggest that inhomogeneities in spatial probability can be learned and used by participants on-line and without prompting as an aid for visual stimulus discrimination and that spatial repetition priming is not a sufficient explanation for this effect. Future models of attention should consider explicitly incorporating the probabilities of targets locations and features.

A probability space for quantum models

Science.gov (United States)

Lemmens, L. F.

2017-06-01

A probability space contains a set of outcomes, a collection of events formed by subsets of the set of outcomes and probabilities defined for all events. A reformulation in terms of propositions allows to use the maximum entropy method to assign the probabilities taking some constraints into account. The construction of a probability space for quantum models is determined by the choice of propositions, choosing the constraints and making the probability assignment by the maximum entropy method. This approach shows, how typical quantum distributions such as Maxwell-Boltzmann, Fermi-Dirac and Bose-Einstein are partly related with well-known classical distributions. The relation between the conditional probability density, given some averages as constraints and the appropriate ensemble is elucidated.

Probability, Nondeterminism and Concurrency

DEFF Research Database (Denmark)

Varacca, Daniele

Nondeterminism is modelled in domain theory by the notion of a powerdomain, while probability is modelled by that of the probabilistic powerdomain. Some problems arise when we want to combine them in order to model computation in which both nondeterminism and probability are present. In particula...

Ignition Probability

Data.gov (United States)

Earth Data Analysis Center, University of New Mexico — USFS, State Forestry, BLM, and DOI fire occurrence point locations from 1987 to 2008 were combined and converted into a fire occurrence probability or density grid...

Probability of Failure in Random Vibration

DEFF Research Database (Denmark)

Nielsen, Søren R.K.; Sørensen, John Dalsgaard

1988-01-01

Close approximations to the first-passage probability of failure in random vibration can be obtained by integral equation methods. A simple relation exists between the first-passage probability density function and the distribution function for the time interval spent below a barrier before out......-crossing. An integral equation for the probability density function of the time interval is formulated, and adequate approximations for the kernel are suggested. The kernel approximation results in approximate solutions for the probability density function of the time interval and thus for the first-passage probability...

Como reescribir funciones aleatorias multivariadas como univariadas para hacer cokrigeage. La teoría

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Adrian Martínez-Vargas

2010-03-01

Full Text Available En el año 2005 Martínez-Vargas formuló un sistema de cokrigeage puro heterotópico para estimar una función aleatoria regionalizada (RF Z*(x definida como la combinación lineal de n RF's univariadas Zi(x, cuyos coeficientes 1i(x son indicatrices de un set disyuntivo de categorías i. Aparentemente este modelo se contradice pues asume que las covarianzas cruzadas existen en un mismo punto, a pesar de su carácter puramente heterotópico. Para evadir dicha contradicción se redefinió el set de RF Zi(x como una única RF Z(x,i, siendo los puntos (x,i y (x,j no coincidentes si i y j no son iguales. La heterotopía fue simplemente considerada como una omisión de la RF Z(x,. en los datos y en los puntos a estimar, no impuesta por el modelo; entonces el resultado es simplemente un caso particular del cokrigeage clásico. Con esta notación se reescribió el sistema de cokrigeage clásico como el sistema de krigeage de la RF univariada Z(x,i, asumiendo que esta posee un drift definido como m(x,i,j, donde los miembros fl(x,i,j de m(x,i,j pueden ser linealmente dependientes o independientes. Bajo esta notación el sistema de krigeage se reduce a un sistema univariado, la existencia de más de una variable o la presencia de heterotropía no impone la necesidad de manipulaciones extras para definir el sistema de ecuaciones de krigeage, incrementándose la eficiencia computacional.

A rota como memória

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Patrick Fraysse

Full Text Available No contexto de estudo do patrimônio por um ponto de vista comunicacional, este artigo permitiu-nos visualisar um objeto de comunicação por excelência « a estrada » como portador de informação a decifrar e a interpretar um documento, mas também como um repositário da memória coletiva, quer dizer um monumento. Paralelamente, a patrimonialização dos monumentos, dos conjuntos arquiteturais e sobretudo dos itinerários que os religam, dito de outra maneira, da estrada, assim como a sua documentarização (relatos de viagens, guias, bancos de dados participam de uma nova institucionalização da memória integrante também das estradas míticas como o caminho de São Tiago na França ou a famosa estrada 66 nos Estados-Unidos.

Role of Rilpivirine and Etravirine in Efavirenz and Nevirapine-Based Regimens Failure in a Resource-Limited Country: A Cross- Sectional Study.

Directory of Open Access Journals (Sweden)

Phairote Teeranaipong

Full Text Available Etravirine(ETR can be used for patients who have failed NNRTI-based regimen. In Thailand, ETR is approximately 45 times more expensive than rilpivirine(RPV. However, there are no data of RPV use in NNRTI failure. Therefore, we assessed the susceptibility and mutation patterns of first line NNRTI failure and the possibility of using RPV compared to ETV in patients who have failed efavirenz(EFV- and nevirapine(NVP-based regimens.Clinical samples with confirmed virological failure from EFV- or NVP-based regimens were retrospectively analyzed. Resistance-associated mutations (RAMs were interpreted by IAS-USA Drug Resistance Mutations. Susceptibility of ETR and RPV were interpreted by DUET, Monogram scoring system, and Stanford University HIV Drug Resistance Database.1,279 and 528 patients failed EFV- and NVP-based regimens, respectively. Y181C was the most common NVP-associated RAM (54.3% vs. 14.7%, p<0.01. K103N was the most common EFV-associated RAM (56.5% vs. 19.1%, P<0.01. The results from all three scoring systems were concordant. 165(11.1% and 161(10.9% patients who failed NVP-based regimen were susceptible to ETR and RPV, respectively (p = 0.85. 195 (32.2% and 191 (31.6% patients who failed EFV-based regimen, were susceptible to ETR and RPV, respectively (p = 0.79. The susceptibility of ETV and RPV in EFV failure was significantly higher than NVP failure (p<0.01.The mutation patterns for ETR and RPV were similar but 32% and 11% of patients who failed EFV and NVP -based regimen, respectivly were susceptible to RPV. This finding suggests that RPV can be used as the alternative antiretroviral agent in patients who have failed EFV-based regimen.

Role of Rilpivirine and Etravirine in Efavirenz and Nevirapine-Based Regimens Failure in a Resource-Limited Country: A Cross- Sectional Study.

Science.gov (United States)

Teeranaipong, Phairote; Sirivichayakul, Sunee; Mekprasan, Suwanna; Ohata, Pirapon June; Avihingsanon, Anchalee; Ruxrungtham, Kiat; Putcharoen, Opass

2016-01-01

Etravirine(ETR) can be used for patients who have failed NNRTI-based regimen. In Thailand, ETR is approximately 45 times more expensive than rilpivirine(RPV). However, there are no data of RPV use in NNRTI failure. Therefore, we assessed the susceptibility and mutation patterns of first line NNRTI failure and the possibility of using RPV compared to ETV in patients who have failed efavirenz(EFV)- and nevirapine(NVP)-based regimens. Clinical samples with confirmed virological failure from EFV- or NVP-based regimens were retrospectively analyzed. Resistance-associated mutations (RAMs) were interpreted by IAS-USA Drug Resistance Mutations. Susceptibility of ETR and RPV were interpreted by DUET, Monogram scoring system, and Stanford University HIV Drug Resistance Database. 1,279 and 528 patients failed EFV- and NVP-based regimens, respectively. Y181C was the most common NVP-associated RAM (54.3% vs. 14.7%, p<0.01). K103N was the most common EFV-associated RAM (56.5% vs. 19.1%, P<0.01). The results from all three scoring systems were concordant. 165(11.1%) and 161(10.9%) patients who failed NVP-based regimen were susceptible to ETR and RPV, respectively (p = 0.85). 195 (32.2%) and 191 (31.6%) patients who failed EFV-based regimen, were susceptible to ETR and RPV, respectively (p = 0.79). The susceptibility of ETV and RPV in EFV failure was significantly higher than NVP failure (p<0.01). The mutation patterns for ETR and RPV were similar but 32% and 11% of patients who failed EFV and NVP -based regimen, respectivly were susceptible to RPV. This finding suggests that RPV can be used as the alternative antiretroviral agent in patients who have failed EFV-based regimen.

Invariant probabilities of transition functions

CERN Document Server

Zaharopol, Radu

2014-01-01

The structure of the set of all the invariant probabilities and the structure of various types of individual invariant probabilities of a transition function are two topics of significant interest in the theory of transition functions, and are studied in this book. The results obtained are useful in ergodic theory and the theory of dynamical systems, which, in turn, can be applied in various other areas (like number theory). They are illustrated using transition functions defined by flows, semiflows, and one-parameter convolution semigroups of probability measures. In this book, all results on transition probabilities that have been published by the author between 2004 and 2008 are extended to transition functions. The proofs of the results obtained are new. For transition functions that satisfy very general conditions the book describes an ergodic decomposition that provides relevant information on the structure of the corresponding set of invariant probabilities. Ergodic decomposition means a splitting of t...

The concept of probability

International Nuclear Information System (INIS)

Bitsakis, E.I.; Nicolaides, C.A.

1989-01-01

The concept of probability is now, and always has been, central to the debate on the interpretation of quantum mechanics. Furthermore, probability permeates all of science, as well as our every day life. The papers included in this volume, written by leading proponents of the ideas expressed, embrace a broad spectrum of thought and results: mathematical, physical epistemological, and experimental, both specific and general. The contributions are arranged in parts under the following headings: Following Schroedinger's thoughts; Probability and quantum mechanics; Aspects of the arguments on nonlocality; Bell's theorem and EPR correlations; Real or Gedanken experiments and their interpretation; Questions about irreversibility and stochasticity; and Epistemology, interpretation and culture. (author). refs.; figs.; tabs

Choice probability generating functions

DEFF Research Database (Denmark)

Fosgerau, Mogens; McFadden, Daniel; Bierlaire, Michel

2010-01-01

This paper establishes that every random utility discrete choice model (RUM) has a representation that can be characterized by a choice-probability generating function (CPGF) with specific properties, and that every function with these specific properties is consistent with a RUM. The choice...... probabilities from the RUM are obtained from the gradient of the CPGF. Mixtures of RUM are characterized by logarithmic mixtures of their associated CPGF. The paper relates CPGF to multivariate extreme value distributions, and reviews and extends methods for constructing generating functions for applications....... The choice probabilities of any ARUM may be approximated by a cross-nested logit model. The results for ARUM are extended to competing risk survival models....

Probability via expectation

CERN Document Server

Whittle, Peter

1992-01-01

This book is a complete revision of the earlier work Probability which ap­ peared in 1970. While revised so radically and incorporating so much new material as to amount to a new text, it preserves both the aim and the approach of the original. That aim was stated as the provision of a 'first text in probability, de­ manding a reasonable but not extensive knowledge of mathematics, and taking the reader to what one might describe as a good intermediate level'. In doing so it attempted to break away from stereotyped applications, and consider applications of a more novel and significant character. The particular novelty of the approach was that expectation was taken as the prime concept, and the concept of expectation axiomatized rather than that of a probability measure. In the preface to the original text of 1970 (reproduced below, together with that to the Russian edition of 1982) I listed what I saw as the advantages of the approach in as unlaboured a fashion as I could. I also took the view that the text...

The probability outcome correpondence principle : a dispositional view of the interpretation of probability statements

NARCIS (Netherlands)

Keren, G.; Teigen, K.H.

2001-01-01

This article presents a framework for lay people's internal representations of probabilities, which supposedly reflect the strength of underlying dispositions, or propensities, associated with the predicted event. From this framework, we derive the probability-outcome correspondence principle, which

Poisson Processes in Free Probability

OpenAIRE

An, Guimei; Gao, Mingchu

2015-01-01

We prove a multidimensional Poisson limit theorem in free probability, and define joint free Poisson distributions in a non-commutative probability space. We define (compound) free Poisson process explicitly, similar to the definitions of (compound) Poisson processes in classical probability. We proved that the sum of finitely many freely independent compound free Poisson processes is a compound free Poisson processes. We give a step by step procedure for constructing a (compound) free Poisso...

Solving probability reasoning based on DNA strand displacement and probability modules.

Science.gov (United States)

Zhang, Qiang; Wang, Xiaobiao; Wang, Xiaojun; Zhou, Changjun

2017-12-01

In computation biology, DNA strand displacement technology is used to simulate the computation process and has shown strong computing ability. Most researchers use it to solve logic problems, but it is only rarely used in probabilistic reasoning. To process probabilistic reasoning, a conditional probability derivation model and total probability model based on DNA strand displacement were established in this paper. The models were assessed through the game "read your mind." It has been shown to enable the application of probabilistic reasoning in genetic diagnosis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Sensitivity of the probability of failure to probability of detection curve regions

International Nuclear Information System (INIS)

Garza, J.; Millwater, H.

2016-01-01

Non-destructive inspection (NDI) techniques have been shown to play a vital role in fracture control plans, structural health monitoring, and ensuring availability and reliability of piping, pressure vessels, mechanical and aerospace equipment. Probabilistic fatigue simulations are often used in order to determine the efficacy of an inspection procedure with the NDI method modeled as a probability of detection (POD) curve. These simulations can be used to determine the most advantageous NDI method for a given application. As an aid to this process, a first order sensitivity method of the probability-of-failure (POF) with respect to regions of the POD curve (lower tail, middle region, right tail) is developed and presented here. The sensitivity method computes the partial derivative of the POF with respect to a change in each region of a POD or multiple POD curves. The sensitivities are computed at no cost by reusing the samples from an existing Monte Carlo (MC) analysis. A numerical example is presented considering single and multiple inspections. - Highlights: • Sensitivities of probability-of-failure to a region of probability-of-detection curve. • The sensitivities are computed with negligible cost. • Sensitivities identify the important region of a POD curve. • Sensitivities can be used as a guide to selecting the optimal POD curve.

Truth, possibility and probability new logical foundations of probability and statistical inference

CERN Document Server

Chuaqui, R

1991-01-01

Anyone involved in the philosophy of science is naturally drawn into the study of the foundations of probability. Different interpretations of probability, based on competing philosophical ideas, lead to different statistical techniques, and frequently to mutually contradictory consequences. This unique book presents a new interpretation of probability, rooted in the traditional interpretation that was current in the 17th and 18th centuries. Mathematical models are constructed based on this interpretation, and statistical inference and decision theory are applied, including some examples in artificial intelligence, solving the main foundational problems. Nonstandard analysis is extensively developed for the construction of the models and in some of the proofs. Many nonstandard theorems are proved, some of them new, in particular, a representation theorem that asserts that any stochastic process can be approximated by a process defined over a space with equiprobable outcomes.

Logic, probability, and human reasoning.

Science.gov (United States)

Johnson-Laird, P N; Khemlani, Sangeet S; Goodwin, Geoffrey P

2015-04-01

This review addresses the long-standing puzzle of how logic and probability fit together in human reasoning. Many cognitive scientists argue that conventional logic cannot underlie deductions, because it never requires valid conclusions to be withdrawn - not even if they are false; it treats conditional assertions implausibly; and it yields many vapid, although valid, conclusions. A new paradigm of probability logic allows conclusions to be withdrawn and treats conditionals more plausibly, although it does not address the problem of vapidity. The theory of mental models solves all of these problems. It explains how people reason about probabilities and postulates that the machinery for reasoning is itself probabilistic. Recent investigations accordingly suggest a way to integrate probability and deduction. Copyright © 2015 Elsevier Ltd. All rights reserved.

Pre-Aggregation with Probability Distributions

DEFF Research Database (Denmark)

Timko, Igor; Dyreson, Curtis E.; Pedersen, Torben Bach

2006-01-01

Motivated by the increasing need to analyze complex, uncertain multidimensional data this paper proposes probabilistic OLAP queries that are computed using probability distributions rather than atomic values. The paper describes how to create probability distributions from base data, and how...... the distributions can be subsequently used in pre-aggregation. Since the probability distributions can become large, we show how to achieve good time and space efficiency by approximating the distributions. We present the results of several experiments that demonstrate the effectiveness of our methods. The work...... is motivated with a real-world case study, based on our collaboration with a leading Danish vendor of location-based services. This paper is the first to consider the approximate processing of probabilistic OLAP queries over probability distributions....

Probability and stochastic modeling

CERN Document Server

Rotar, Vladimir I

2012-01-01

Basic NotionsSample Space and EventsProbabilitiesCounting TechniquesIndependence and Conditional ProbabilityIndependenceConditioningThe Borel-Cantelli TheoremDiscrete Random VariablesRandom Variables and VectorsExpected ValueVariance and Other Moments. Inequalities for DeviationsSome Basic DistributionsConvergence of Random Variables. The Law of Large NumbersConditional ExpectationGenerating Functions. Branching Processes. Random Walk RevisitedBranching Processes Generating Functions Branching Processes Revisited More on Random WalkMarkov ChainsDefinitions and Examples. Probability Distributions of Markov ChainsThe First Step Analysis. Passage TimesVariables Defined on a Markov ChainErgodicity and Stationary DistributionsA Classification of States and ErgodicityContinuous Random VariablesContinuous DistributionsSome Basic Distributions Continuous Multivariate Distributions Sums of Independent Random Variables Conditional Distributions and ExpectationsDistributions in the General Case. SimulationDistribution F...

Differences in response to antiretroviral therapy in HIV-positive patients being treated for tuberculosis in Eastern Europe, Western Europe and Latin America

DEFF Research Database (Denmark)

Caro-Vega, Yanink; Schultze, Anna; W Efsen, Anne Marie

2018-01-01

-positive patients aged ≥16 years with a diagnosis of tuberculosis recruited to the TB:HIV study between Jan 1, 2011, and Dec 31, 2013 in 19 countries in Eastern Europe (EE), Western Europe (WE), and Latin America (LA) who received ART concomitantly with TB treatment were included. Patients either received efavirenz......-containing ART, and 318 a non-efavirenz regimen) 50% were from EE, 28% from WE, and 22% from LA. Among those not receiving efavirenz-containing ART, regimens mainly contained a ritonavir-boosted protease inhibitor (57%), or raltegravir (22%). At 12 months 1.4% of patients in WE had died, compared to 20% in EE...

Transitional Probabilities Are Prioritized over Stimulus/Pattern Probabilities in Auditory Deviance Detection: Memory Basis for Predictive Sound Processing.

Science.gov (United States)

Mittag, Maria; Takegata, Rika; Winkler, István

2016-09-14

Representations encoding the probabilities of auditory events do not directly support predictive processing. In contrast, information about the probability with which a given sound follows another (transitional probability) allows predictions of upcoming sounds. We tested whether behavioral and cortical auditory deviance detection (the latter indexed by the mismatch negativity event-related potential) relies on probabilities of sound patterns or on transitional probabilities. We presented healthy adult volunteers with three types of rare tone-triplets among frequent standard triplets of high-low-high (H-L-H) or L-H-L pitch structure: proximity deviant (H-H-H/L-L-L), reversal deviant (L-H-L/H-L-H), and first-tone deviant (L-L-H/H-H-L). If deviance detection was based on pattern probability, reversal and first-tone deviants should be detected with similar latency because both differ from the standard at the first pattern position. If deviance detection was based on transitional probabilities, then reversal deviants should be the most difficult to detect because, unlike the other two deviants, they contain no low-probability pitch transitions. The data clearly showed that both behavioral and cortical auditory deviance detection uses transitional probabilities. Thus, the memory traces underlying cortical deviance detection may provide a link between stimulus probability-based change/novelty detectors operating at lower levels of the auditory system and higher auditory cognitive functions that involve predictive processing. Our research presents the first definite evidence for the auditory system prioritizing transitional probabilities over probabilities of individual sensory events. Forming representations for transitional probabilities paves the way for predictions of upcoming sounds. Several recent theories suggest that predictive processing provides the general basis of human perception, including important auditory functions, such as auditory scene analysis. Our

The effect of malnutrition on the pharmacokinetics and virologic outcomes of lopinavir, efavirenz and nevirapine in food insecure HIV-infected children in Tororo, Uganda.

Science.gov (United States)

Bartelink, Imke H; Savic, Rada M; Dorsey, Grant; Ruel, Theodore; Gingrich, David; Scherpbier, Henriette J; Capparelli, Edmund; Jullien, Vincent; Young, Sera L; Achan, Jane; Plenty, Albert; Charlebois, Edwin; Kamya, Moses; Havlir, Diane; Aweeka, Francesca

2015-03-01

Malnutrition may impact the pharmacokinetics (PKs) of antiretroviral medications and virologic responses in HIV-infected children. The authors therefore evaluated the PK of nevirapine (NVP), efavirenz (EFV) and lopinavir (LPV) in associations with nutritional status in a cohort of HIV-infected Ugandan children. Sparse dried blood spot samples from Ugandan children were used to estimate plasma concentrations. Historical PK data from children from 3 resource-rich countries (RRC) were utilized to develop the PK models. Concentrations in 330 dried blood spot from 163 Ugandan children aged 0.7-7 years were analyzed in reference to plasma PK data (1189 samples) from 204 children from RRC aged 0.5-12 years. Among Ugandan children, 48% was malnourished (underweight, thin or stunted). Compared to RRC, Ugandan children exhibited reduced bioavailability of EFV and LPV; 11% (P=0.045) and 18% (P=0.008), respectively. In contrast, NVP bioavailability was 46% higher in Ugandan children (PChildren receiving LPV, EFV or NVP had comparable risk of virologic failure. Among children on NVP, low height and weight for age Z scores were associated with reduced risk of virologic failure (P=0.034, P=0.068, respectively). Ugandan children demonstrated lower EFV and LPV and higher NVP exposure compared to children in RRC, perhaps reflecting the consequence of malnutrition on bioavailability. In children receiving NVP, the relation between exposure, malnutrition and outcome turned out to be marginally significant. Further investigations are warranted using more intensive PK measurements and adequate adherence assessments, to further assess causes of virologic failure in Ugandan children.

Brief Report: CYP2B6 516G>T Minor Allele Protective of Late Virologic Failure in Efavirenz-Treated HIV-Infected Patients in Botswana.

Science.gov (United States)

Vujkovic, Marijana; Bellamy, Scarlett L; Zuppa, Athena F; Gastonguay, Marc; Moorthy, Ganesh S; Ratshaa, Bakgaki R; Han, Xiaoyan; Steenhoff, Andrew P; Mosepele, Mosepele; Strom, Brian L; Aplenc, Richard; Bisson, Gregory P; Gross, Robert

2017-08-01

CYP2B6 polymorphisms that affect efavirenz (EFV) concentrations are common, but the effect of this polymorphism on HIV virologic failure in clinical practice settings has not fully been elucidated. Our objective was to investigate the relationship between the CYP2B6 516G>T genotype and late virologic failure in patients treated with EFV in Gaborone, Botswana. We performed a case-control study that included 1338 HIV-infected black Batswana on EFV-based antiretroviral therapy (ART). Patients were approached for enrollment during regular visits at one of the outpatient HIV clinics between July 2013 and April 2014. Cases experienced late HIV failure, defined as plasma HIV RNA >1000 copies/mL after maintaining viral suppression (ART for at least 6 months. Logistic regression was used to determine the adjusted odds of late HIV failure by 516G>T genotype. After adjustment for the confounding variables age and CD4 count, the CYP2B6 516 T-allele was protective against late HIV virologic breakthrough, adjusted OR 0.70; 95% CI: 0.50 to 0.97. The CYP2B6 516 T-allele was protective against late virologic breakthrough in patients with initial (6 month) HIV RNA suppression on EFV-based ART. Future studies are needed to assess long-term viral benefits of identifying and offering EFV containing ART to black African HIV-infected patients with CYP2B6 T-alleles, especially given the wider availability of a single pill EFV in this setting.

Probability tales

CERN Document Server

Grinstead, Charles M; Snell, J Laurie

2011-01-01

This book explores four real-world topics through the lens of probability theory. It can be used to supplement a standard text in probability or statistics. Most elementary textbooks present the basic theory and then illustrate the ideas with some neatly packaged examples. Here the authors assume that the reader has seen, or is learning, the basic theory from another book and concentrate in some depth on the following topics: streaks, the stock market, lotteries, and fingerprints. This extended format allows the authors to present multiple approaches to problems and to pursue promising side discussions in ways that would not be possible in a book constrained to cover a fixed set of topics. To keep the main narrative accessible, the authors have placed the more technical mathematical details in appendices. The appendices can be understood by someone who has taken one or two semesters of calculus.

A Tale of Two Probabilities

Science.gov (United States)

Falk, Ruma; Kendig, Keith

2013-01-01

Two contestants debate the notorious probability problem of the sex of the second child. The conclusions boil down to explication of the underlying scenarios and assumptions. Basic principles of probability theory are highlighted.

Hoy como ayer

Directory of Open Access Journals (Sweden)

Rodríguez M.

2010-06-01

Full Text Available Leyendo el artículo titulado “Los medicamentos baratos” de la revista La Farmacia Española, publicada en Madrid el jueves 21 de diciembre de 1893, uno se pregunta cómo puede ser que se reconozca la situación como si fuera de ahora mismo, cómo puede ser que estemos igual que hace más de cien años. Entonces eran los descuentos que se empezaban a extender en las farmacias, francesas sobre todo, y que amenazaban el prestigio profesional de todo el colectivo. Con frases como éstas se define la situación que se presentaba en aquel momento: “…el desprestigio de que vaya por unos cuantos desnaturalizándose el ejercicio de la farmacia en tal forma que se convierta en un comercio impuro y de la peor estofa; pero conviene mucho combatir con mano firme la tendencia a la baratería, tanto más cuanto que no puede dudarse que significa un rebajamiento a todas luces nocivo y que supone una desorganización que nos llevaría en breve a la más completa ruina, y lo que creo aún más grave, a la desmoralización y el desorden, que no se compadecen en modo alguno con lo que en realidad es hoy y ha sido siempre el ejercicio de una profesión genuinamente científica como lo es la de la farmacia”. La propuesta que se hacía para controlar la situación era “la limitación de farmacias, con vigilancia estrecha del Estado y tarifa uniforme oficial”, así como “hace falta mucha inteligencia y mucha unión, hace falta que nadie permanezca indiferente, que todos y cada uno pongan de su parte lo que puedan”. Nuestra profesión mezcla una doble vertiente sanitaria y comercial que no siempre es fácil mantener equilibrada y, por lo que se ve, esto ha ocurrido así desde siempre. El problema que existe hoy en día es la mercantilización de la farmacia, un desplazamiento de establecimiento sanitario hacia una simple empresa.

Impact of controlling the sum of error probability in the sequential probability ratio test

Directory of Open Access Journals (Sweden)

Bijoy Kumarr Pradhan

2013-05-01

Full Text Available A generalized modified method is proposed to control the sum of error probabilities in sequential probability ratio test to minimize the weighted average of the two average sample numbers under a simple null hypothesis and a simple alternative hypothesis with the restriction that the sum of error probabilities is a pre-assigned constant to find the optimal sample size and finally a comparison is done with the optimal sample size found from fixed sample size procedure. The results are applied to the cases when the random variate follows a normal law as well as Bernoullian law.

El videojuego como material educativo: La Odisea

Directory of Open Access Journals (Sweden)

Belén Mainer Blanco

2012-04-01

Full Text Available La investigación se basa en la función educativa que pueden cumplir los videojuegos, un campo que consideramos inexplorado por tres motivos principalmente: su reciente incorporación, su impopularidad educativa (el rechazo el videojuego como herramienta de aprendizaje y considerado, por el contrario, como una distracción, y la incompleta incorporación de las nuevas tecnologías de información y comunicación (TIC en el ámbito familiar y educativo. En una segunda parte, se ha realizado una aplicación práctica tomando como referencia la gran obra universal “La Odisea”, cuya intención es mostrar la utilidad del videojuego como complemento educativo.

Upgrading Probability via Fractions of Events

Directory of Open Access Journals (Sweden)

Frič Roman

2016-08-01

Full Text Available The influence of “Grundbegriffe” by A. N. Kolmogorov (published in 1933 on education in the area of probability and its impact on research in stochastics cannot be overestimated. We would like to point out three aspects of the classical probability theory “calling for” an upgrade: (i classical random events are black-and-white (Boolean; (ii classical random variables do not model quantum phenomena; (iii basic maps (probability measures and observables { dual maps to random variables have very different “mathematical nature”. Accordingly, we propose an upgraded probability theory based on Łukasiewicz operations (multivalued logic on events, elementary category theory, and covering the classical probability theory as a special case. The upgrade can be compared to replacing calculations with integers by calculations with rational (and real numbers. Namely, to avoid the three objections, we embed the classical (Boolean random events (represented by the f0; 1g-valued indicator functions of sets into upgraded random events (represented by measurable {0; 1}-valued functions, the minimal domain of probability containing “fractions” of classical random events, and we upgrade the notions of probability measure and random variable.

A Comprehensive Probability Project for the Upper Division One-Semester Probability Course Using Yahtzee

Science.gov (United States)

Wilson, Jason; Lawman, Joshua; Murphy, Rachael; Nelson, Marissa

2011-01-01

This article describes a probability project used in an upper division, one-semester probability course with third-semester calculus and linear algebra prerequisites. The student learning outcome focused on developing the skills necessary for approaching project-sized math/stat application problems. These skills include appropriately defining…

Incidence of nevirapine-associated hepatitis in an antenatal clinic

African Journals Online (AJOL)

2008-01-22

Jan 22, 2008 ... together with a non-nucleoside reverse transcriptase inhibitor, either efavirenz or nevirapine.1 As efavirenz is thought to be a teratogen and is classified as a Food and Drug Administration. (FDA) category D drug, nevirapine is the preferred agent for use in pregnant women, for women planning a pregnancy ...

Is probability of frequency too narrow?

International Nuclear Information System (INIS)

Martz, H.F.

1993-01-01

Modern methods of statistical data analysis, such as empirical and hierarchical Bayesian methods, should find increasing use in future Probabilistic Risk Assessment (PRA) applications. In addition, there will be a more formalized use of expert judgment in future PRAs. These methods require an extension of the probabilistic framework of PRA, in particular, the popular notion of probability of frequency, to consideration of frequency of frequency, frequency of probability, and probability of probability. The genesis, interpretation, and examples of these three extended notions are discussed

Contabilidade gerencial como apoio ao "just in time"

OpenAIRE

Costa, Sérgio De Carvalho

2010-01-01

Descreve as técnicas da filosofia "Just in Time" e apresenta as modificações necessárias aos Sistemas Gerencias para que se tornem coerentes com a filosofia JIT, bem como meçam adequadamente a melhoria contínua da Empresa. Critica tanto o Custeio' Direto como o Custeio por Absorção, apresentando como alternativa o Custeio "ABC". Mostra como o JIT facilita o Custeio dos Produtos e destaca os aspectos estratégicos da Avaliação de Desempenho. Finalmente discorre sobre um estudo de...

An Alternative Version of Conditional Probabilities and Bayes' Rule: An Application of Probability Logic

Science.gov (United States)

Satake, Eiki; Amato, Philip P.

2008-01-01

This paper presents an alternative version of formulas of conditional probabilities and Bayes' rule that demonstrate how the truth table of elementary mathematical logic applies to the derivations of the conditional probabilities of various complex, compound statements. This new approach is used to calculate the prior and posterior probabilities…

Normal probability plots with confidence.

Science.gov (United States)

Chantarangsi, Wanpen; Liu, Wei; Bretz, Frank; Kiatsupaibul, Seksan; Hayter, Anthony J; Wan, Fang

2015-01-01

Normal probability plots are widely used as a statistical tool for assessing whether an observed simple random sample is drawn from a normally distributed population. The users, however, have to judge subjectively, if no objective rule is provided, whether the plotted points fall close to a straight line. In this paper, we focus on how a normal probability plot can be augmented by intervals for all the points so that, if the population distribution is normal, then all the points should fall into the corresponding intervals simultaneously with probability 1-α. These simultaneous 1-α probability intervals provide therefore an objective mean to judge whether the plotted points fall close to the straight line: the plotted points fall close to the straight line if and only if all the points fall into the corresponding intervals. The powers of several normal probability plot based (graphical) tests and the most popular nongraphical Anderson-Darling and Shapiro-Wilk tests are compared by simulation. Based on this comparison, recommendations are given in Section 3 on which graphical tests should be used in what circumstances. An example is provided to illustrate the methods. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

El Derecho Agrario como derecho para la paz

Directory of Open Access Journals (Sweden)

Ricardo Zeledón Zeledón

2015-01-01

Full Text Available Contenido: El Derecho agrario surgido de la paz y para la consolidación de la paz, como fuente e instrumento para su cumplimiento. La visión de Carrozza como conjunto de reglas destinadas al fin de la paz, y la equidad. Explicación de un Derecho agrario vinculado a la paz por su origen en los Derechos Humanos Económicos y Sociales. Evolución del Derecho Agrario en los Derechos Humanos de la tercera generación (principalmente ambiente, desarrollo y paz, en las nuevas dimensiones del Derecho agrario del futuro. Derecho agrario como derecho para la paz y el respeto de los derechos humanos. Desarrollo sostenible y agricultura del futuro. La nueva orientación de los institutos del derecho agrario como instrumentos de paz, dirigidos a cumplir los fines de la justicia social, el desarrollo económico y el equilibrio ambiental. Desarrollo como respuesta a los problemas del ambiente, alimentario, de la pobreza, indígena y de la mujer rural. El rol de la justicia agraria y ambiental como derecho para la paz. El derecho agrario, disciplina forjada en una concepción iushumanista, acorde con los derechos humanos y la paz. El derecho agrario como derecho para la paz.

Los ritmos como terapia para la impulsividad

Directory of Open Access Journals (Sweden)

Mónica Triviño

2012-10-01

Full Text Available Investigaciones recientes muestran que el uso de patrones rítmicos facilita la respuesta óptima en el tiempo, por lo que el entrenamiento mediante ritmos podría proponerse como terapia novedosa ante problemas como la impulsividad. Esto podría beneficiar a pacientes con daño prefrontal o personas con trastorno por déficit de atención e hiperactividad (TDAH, que suelen mostrar conductas impulsivas, así como dificultad para estimar el paso del tiempo.

Free probability and random matrices

CERN Document Server

Mingo, James A

2017-01-01

This volume opens the world of free probability to a wide variety of readers. From its roots in the theory of operator algebras, free probability has intertwined with non-crossing partitions, random matrices, applications in wireless communications, representation theory of large groups, quantum groups, the invariant subspace problem, large deviations, subfactors, and beyond. This book puts a special emphasis on the relation of free probability to random matrices, but also touches upon the operator algebraic, combinatorial, and analytic aspects of the theory. The book serves as a combination textbook/research monograph, with self-contained chapters, exercises scattered throughout the text, and coverage of important ongoing progress of the theory. It will appeal to graduate students and all mathematicians interested in random matrices and free probability from the point of view of operator algebras, combinatorics, analytic functions, or applications in engineering and statistical physics.

Probability with applications and R

CERN Document Server

Dobrow, Robert P

2013-01-01

An introduction to probability at the undergraduate level Chance and randomness are encountered on a daily basis. Authored by a highly qualified professor in the field, Probability: With Applications and R delves into the theories and applications essential to obtaining a thorough understanding of probability. With real-life examples and thoughtful exercises from fields as diverse as biology, computer science, cryptology, ecology, public health, and sports, the book is accessible for a variety of readers. The book's emphasis on simulation through the use of the popular R software language c

A philosophical essay on probabilities

CERN Document Server

Laplace, Marquis de

1996-01-01

A classic of science, this famous essay by ""the Newton of France"" introduces lay readers to the concepts and uses of probability theory. It is of especial interest today as an application of mathematical techniques to problems in social and biological sciences.Generally recognized as the founder of the modern phase of probability theory, Laplace here applies the principles and general results of his theory ""to the most important questions of life, which are, in effect, for the most part, problems in probability."" Thus, without the use of higher mathematics, he demonstrates the application

Development and validation of a liquid chromatography-MS/MS method for simultaneous quantification of tenofovir and efavirenz in biological tissues and fluids.

Science.gov (United States)

Barreiros, Luisa; Cunha-Reis, Cassilda; Silva, Eduarda M P; Carvalho, Joana R B; das Neves, José; Sarmento, Bruno; Segundo, Marcela A

2017-03-20

Millions of people worldwide live with human immunodeficiency virus (HIV) infection thus justifying the continuous search for new prevention and treatment strategies, including topical microbicide products combining antiretroviral drugs (ARVs) such as tenofovir (TFV) and efavirenz (EFV). Therefore, the aim of this work was to develop and validate a high performance liquid chromatography method coupled to triple quadrupole-tandem mass spectrometry (HPLC-MS/MS) for the quantification of TFV and EFV in biological matrices (mouse vaginal tissue, vaginal lavage and blood plasma). Chromatographic separation was achieved using a reversed phase C18 column (3μm, 100×2.1mm) at 45°C and elution in gradient mode using a combination of 0.1% (v/v) formic acid in water and 0.1% (v/v) formic acid in acetonitrile at 0.35mLmin -1 . Total run time was 9min, with retention time of 2.8 and 4.1min for TFV and EFV, respectively. The MS was operated in positive ionization mode (ESI+) for TFV and in negative ionization mode (ESI-) for EFV detection. Data were acquired in selected reaction monitoring (SRM) mode and deuterated ARVs were employed as internal standards. Calibration curves were linear for ARV concentrations ranging from 4 to 500ngmL -1 with LOD and LOQ for both analytes ≤0.4 and ≤0.7ngmL -1 in sample extracts, respectively. The method was found to be specific, accurate (96.0-106.0% of nominal values) and precise (RSDfluids were ≥88.4%. Matrix effects were observed for EFV determination in tissue and plasma extracts but compensated by the use of deuterated internal standards. The proposed methodology was successfully applied to a pharmacokinetic study following intravaginal administration of both ARVs. Copyright © 2016 Elsevier B.V. All rights reserved.

Alternative probability theories for cognitive psychology.

Science.gov (United States)

Narens, Louis

2014-01-01

Various proposals for generalizing event spaces for probability functions have been put forth in the mathematical, scientific, and philosophic literatures. In cognitive psychology such generalizations are used for explaining puzzling results in decision theory and for modeling the influence of context effects. This commentary discusses proposals for generalizing probability theory to event spaces that are not necessarily boolean algebras. Two prominent examples are quantum probability theory, which is based on the set of closed subspaces of a Hilbert space, and topological probability theory, which is based on the set of open sets of a topology. Both have been applied to a variety of cognitive situations. This commentary focuses on how event space properties can influence probability concepts and impact cognitive modeling. Copyright © 2013 Cognitive Science Society, Inc.

Probability theory and mathematical statistics for engineers

CERN Document Server

Pugachev, V S

1984-01-01

Probability Theory and Mathematical Statistics for Engineers focuses on the concepts of probability theory and mathematical statistics for finite-dimensional random variables.The publication first underscores the probabilities of events, random variables, and numerical characteristics of random variables. Discussions focus on canonical expansions of random vectors, second-order moments of random vectors, generalization of the density concept, entropy of a distribution, direct evaluation of probabilities, and conditional probabilities. The text then examines projections of random vector

Introduction to probability theory with contemporary applications

CERN Document Server

Helms, Lester L

2010-01-01

This introduction to probability theory transforms a highly abstract subject into a series of coherent concepts. Its extensive discussions and clear examples, written in plain language, expose students to the rules and methods of probability. Suitable for an introductory probability course, this volume requires abstract and conceptual thinking skills and a background in calculus.Topics include classical probability, set theory, axioms, probability functions, random and independent random variables, expected values, and covariance and correlations. Additional subjects include stochastic process

Probability in quantum mechanics

Directory of Open Access Journals (Sweden)

J. G. Gilson

1982-01-01

Full Text Available By using a fluid theory which is an alternative to quantum theory but from which the latter can be deduced exactly, the long-standing problem of how quantum mechanics is related to stochastic processes is studied. It can be seen how the Schrödinger probability density has a relationship to time spent on small sections of an orbit, just as the probability density has in some classical contexts.

Pre-Service Teachers' Conceptions of Probability

Science.gov (United States)

Odafe, Victor U.

2011-01-01

Probability knowledge and skills are needed in science and in making daily decisions that are sometimes made under uncertain conditions. Hence, there is the need to ensure that the pre-service teachers of our children are well prepared to teach probability. Pre-service teachers' conceptions of probability are identified, and ways of helping them…

Nuclear data uncertainties: I, Basic concepts of probability

Energy Technology Data Exchange (ETDEWEB)

Smith, D.L.

1988-12-01

Some basic concepts of probability theory are presented from a nuclear-data perspective, in order to provide a foundation for thorough understanding of the role of uncertainties in nuclear data research. Topics included in this report are: events, event spaces, calculus of events, randomness, random variables, random-variable distributions, intuitive and axiomatic probability, calculus of probability, conditional probability and independence, probability distributions, binomial and multinomial probability, Poisson and interval probability, normal probability, the relationships existing between these probability laws, and Bayes' theorem. This treatment emphasizes the practical application of basic mathematical concepts to nuclear data research, and it includes numerous simple examples. 34 refs.

Nuclear data uncertainties: I, Basic concepts of probability

International Nuclear Information System (INIS)

Smith, D.L.

1988-12-01

Some basic concepts of probability theory are presented from a nuclear-data perspective, in order to provide a foundation for thorough understanding of the role of uncertainties in nuclear data research. Topics included in this report are: events, event spaces, calculus of events, randomness, random variables, random-variable distributions, intuitive and axiomatic probability, calculus of probability, conditional probability and independence, probability distributions, binomial and multinomial probability, Poisson and interval probability, normal probability, the relationships existing between these probability laws, and Bayes' theorem. This treatment emphasizes the practical application of basic mathematical concepts to nuclear data research, and it includes numerous simple examples. 34 refs

LOS ACTORES DEL ESCENARIO PEDAGÓGICO COMO COMPONENTE DEL MODELO PEDAGÓGICO PARA INDISCIPLINAR EL DERECHO COMO CIENCIA

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Jorge Eduardo Vásquez Santamaría

2011-01-01

Full Text Available Resultado del escenario pedagógico como plataforma inicial problematizadora a partir de la cual se identifican y describen fundamentos orientadores tradicionales y no tradicionales que permitan reevaluar el Derecho para acreditarlo como ciencia social, se exponen los resultados obtenidos en el trabajo de campo adelantado con abogados docentes y estudiantes de Derecho como sus actores pedagógicos, quienes representan los elementos “Quién” y “A quién” del modelo pedagógico, en este caso primordialmente tradicionalista, imperante en los currículos de los programas de Derecho deColombia.

Economic choices reveal probability distortion in macaque monkeys.

Science.gov (United States)

Stauffer, William R; Lak, Armin; Bossaerts, Peter; Schultz, Wolfram

2015-02-18

Economic choices are largely determined by two principal elements, reward value (utility) and probability. Although nonlinear utility functions have been acknowledged for centuries, nonlinear probability weighting (probability distortion) was only recently recognized as a ubiquitous aspect of real-world choice behavior. Even when outcome probabilities are known and acknowledged, human decision makers often overweight low probability outcomes and underweight high probability outcomes. Whereas recent studies measured utility functions and their corresponding neural correlates in monkeys, it is not known whether monkeys distort probability in a manner similar to humans. Therefore, we investigated economic choices in macaque monkeys for evidence of probability distortion. We trained two monkeys to predict reward from probabilistic gambles with constant outcome values (0.5 ml or nothing). The probability of winning was conveyed using explicit visual cues (sector stimuli). Choices between the gambles revealed that the monkeys used the explicit probability information to make meaningful decisions. Using these cues, we measured probability distortion from choices between the gambles and safe rewards. Parametric modeling of the choices revealed classic probability weighting functions with inverted-S shape. Therefore, the animals overweighted low probability rewards and underweighted high probability rewards. Empirical investigation of the behavior verified that the choices were best explained by a combination of nonlinear value and nonlinear probability distortion. Together, these results suggest that probability distortion may reflect evolutionarily preserved neuronal processing. Copyright © 2015 Stauffer et al.

LA CUESTIÓN AGRARIA COMO ENFOQUE Y COMO PROBLEMA

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Carlos Salgado

2000-01-01

Full Text Available Este ensayo trata de llamar la atención sobre los problemas del agro hoy, colocando especial énfasis en la disrupción entre las razones tecnológicas -que se asumen como ideológicas-, económicas y políticas que han inspirado el desarrollo del agro, o mejor, sobre las cuales se han basado las políticas de crecimiento agropecuario.

La realidad como materia novelable: Alejo Carpentier

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Raquel Arias Careaga

2007-12-01

Full Text Available Desde que en 1897 Benito Pérez Galdós defendiera como materia prima legítima de la literatura «la vida misma, de donde el artista saca las ficciones que nos instruyen y embelesan» (Pérez Galdós, 1990: 159, el realismo como instrumento de indagación y análisis de la sociedad no ha dejado de crecer y expandirse. Realismo crítico, como este de Galdós, que implica una ampliación del concepto chato de «realidad», incluyendo en ella «recuerdos, sueños, imaginación, locura, símbolos» para contribuir a la formación de un «realismo total» (Rodríguez Puértolas, 2000, II: 93, al que se une también la asimilación de enseñanzas esenciales como la que representa la narrativa de Cervantes: La novelística de Galdós hunde sus raíces en el mejor Cervantes, como puede verse en su peculiar sentido del humor y de la ironía, en la concepción perspectivista de la realidad y en tantas otras cosas, algunas de ellas en verdad fundamentales. Así el concepto de la Naturaleza y sus relaciones dialécticas con el ser humano; así el Amor como elemento vital y animador del orden cósmico, muy alejado del idealismo vulgar romántico (Ibid., 93.

Expected utility with lower probabilities

DEFF Research Database (Denmark)

Hendon, Ebbe; Jacobsen, Hans Jørgen; Sloth, Birgitte

1994-01-01

An uncertain and not just risky situation may be modeled using so-called belief functions assigning lower probabilities to subsets of outcomes. In this article we extend the von Neumann-Morgenstern expected utility theory from probability measures to belief functions. We use this theory...

El humanismo como paradigma de la enfermería como ciencia

Directory of Open Access Journals (Sweden)

Núñez Gómez Nicolás Arturo

1999-12-01

Full Text Available

Humanism's philosophical conception is presented to development a paradigm of nursing science. The nursing from creation has been guided toward professional practice and category; of Care has been fundamental contribution. In this article our intends is to grow some fine general of reflection so that nurses contribute to development of a science called nursing and whose accent is man in their multiple dimensions.

A partir del humanismo como concepción filosófica se presenta una propuesta para crear un paradigma de la enfermería como ciencia. Desde su creación, la enfermería se ha orientado hacia su práctica profesional y la categoría de cuidado ha sido su aporte fundamental. Este artículo se propone crear unas líneas generales de reflexión, para que las enfermeras aporten al desarrollo de una ciencia llamada enfermería y cuyo acento es el hombre en sus múltiples dimensiones.

Striatal activity is modulated by target probability.

Science.gov (United States)

Hon, Nicholas

2017-06-14

Target probability has well-known neural effects. In the brain, target probability is known to affect frontal activity, with lower probability targets producing more prefrontal activation than those that occur with higher probability. Although the effect of target probability on cortical activity is well specified, its effect on subcortical structures such as the striatum is less well understood. Here, I examined this issue and found that the striatum was highly responsive to target probability. This is consistent with its hypothesized role in the gating of salient information into higher-order task representations. The current data are interpreted in light of that fact that different components of the striatum are sensitive to different types of task-relevant information.

Failure probability analysis of optical grid

Science.gov (United States)

Zhong, Yaoquan; Guo, Wei; Sun, Weiqiang; Jin, Yaohui; Hu, Weisheng

2008-11-01

Optical grid, the integrated computing environment based on optical network, is expected to be an efficient infrastructure to support advanced data-intensive grid applications. In optical grid, the faults of both computational and network resources are inevitable due to the large scale and high complexity of the system. With the optical network based distributed computing systems extensive applied in the processing of data, the requirement of the application failure probability have been an important indicator of the quality of application and an important aspect the operators consider. This paper will present a task-based analysis method of the application failure probability in optical grid. Then the failure probability of the entire application can be quantified, and the performance of reducing application failure probability in different backup strategies can be compared, so that the different requirements of different clients can be satisfied according to the application failure probability respectively. In optical grid, when the application based DAG (directed acyclic graph) is executed in different backup strategies, the application failure probability and the application complete time is different. This paper will propose new multi-objective differentiated services algorithm (MDSA). New application scheduling algorithm can guarantee the requirement of the failure probability and improve the network resource utilization, realize a compromise between the network operator and the application submission. Then differentiated services can be achieved in optical grid.

Montagem e Imagem como Paradigma

Directory of Open Access Journals (Sweden)

Cesar Huapaya

2016-01-01

Full Text Available O pensar como montagem e imagem tornou-se um método revelador nos processos de estudos práticos e teóricos do artista e dos pesquisadores nos séculos XX e XXI. Este artigo procura articular três formas de pensar por montagem: nas obras de Bertolt Brecht, Sergei Eisenstein e Georges DidiHuberman. O filósofo e historiador da arte Georges Didi-Huberman reinaugura o debate e o exercício de pensar a antropologia da imagem e a montagem como metalinguagem e forma de conhecimento.

La biblioteca como editora de contenidos

Directory of Open Access Journals (Sweden)

Alonso-Arévalo, Julio

2015-12-01

Full Text Available Una de las características más innovadoras de la biblioteca del siglo 21 tiene que ver con la toma de una postura activa frente a la gestión y generación de contenidos. Con la llegada de la Web 2.0 las bibliotecas no sólo siguen salvaguardando y difundiendo información como han venido realizando a lo largo de su historia, también cada vez con más frecuencia crean nueva información con el objetivo de prestar los mejores servicios a sus ciudadanos, a través de recursos y servicios tales como la elaboración guías de investigación, boletines de alerta y novedades, recursos web, información a través de sus blogs, y como administradores de contenidos a través de repositorios y revistas de acceso abierto. Un paso más allá en esta dinámica tienen que ver con la biblioteca como editora y distribuidora de libros, especialmente en el ámbito local, siendo la impulsora, formadora, dinamizador y difusoras de las obras de los autores de su comunidad.

An Objective Theory of Probability (Routledge Revivals)

CERN Document Server

Gillies, Donald

2012-01-01

This reissue of D. A. Gillies highly influential work, first published in 1973, is a philosophical theory of probability which seeks to develop von Mises' views on the subject. In agreement with von Mises, the author regards probability theory as a mathematical science like mechanics or electrodynamics, and probability as an objective, measurable concept like force, mass or charge. On the other hand, Dr Gillies rejects von Mises' definition of probability in terms of limiting frequency and claims that probability should be taken as a primitive or undefined term in accordance with modern axioma

Fundamentals of applied probability and random processes

CERN Document Server

Ibe, Oliver

2014-01-01

The long-awaited revision of Fundamentals of Applied Probability and Random Processes expands on the central components that made the first edition a classic. The title is based on the premise that engineers use probability as a modeling tool, and that probability can be applied to the solution of engineering problems. Engineers and students studying probability and random processes also need to analyze data, and thus need some knowledge of statistics. This book is designed to provide students with a thorough grounding in probability and stochastic processes, demonstrate their applicability t

Defining Probability in Sex Offender Risk Assessment.

Science.gov (United States)

Elwood, Richard W

2016-12-01

There is ongoing debate and confusion over using actuarial scales to predict individuals' risk of sexual recidivism. Much of the debate comes from not distinguishing Frequentist from Bayesian definitions of probability. Much of the confusion comes from applying Frequentist probability to individuals' risk. By definition, only Bayesian probability can be applied to the single case. The Bayesian concept of probability resolves most of the confusion and much of the debate in sex offender risk assessment. Although Bayesian probability is well accepted in risk assessment generally, it has not been widely used to assess the risk of sex offenders. I review the two concepts of probability and show how the Bayesian view alone provides a coherent scheme to conceptualize individuals' risk of sexual recidivism.

UT Biomedical Informatics Lab (BMIL) probability wheel

Science.gov (United States)

Huang, Sheng-Cheng; Lee, Sara; Wang, Allen; Cantor, Scott B.; Sun, Clement; Fan, Kaili; Reece, Gregory P.; Kim, Min Soon; Markey, Mia K.

A probability wheel app is intended to facilitate communication between two people, an "investigator" and a "participant", about uncertainties inherent in decision-making. Traditionally, a probability wheel is a mechanical prop with two colored slices. A user adjusts the sizes of the slices to indicate the relative value of the probabilities assigned to them. A probability wheel can improve the adjustment process and attenuate the effect of anchoring bias when it is used to estimate or communicate probabilities of outcomes. The goal of this work was to develop a mobile application of the probability wheel that is portable, easily available, and more versatile. We provide a motivating example from medical decision-making, but the tool is widely applicable for researchers in the decision sciences.

Quantum computing and probability.

Science.gov (United States)

Ferry, David K

2009-11-25

Over the past two decades, quantum computing has become a popular and promising approach to trying to solve computationally difficult problems. Missing in many descriptions of quantum computing is just how probability enters into the process. Here, we discuss some simple examples of how uncertainty and probability enter, and how this and the ideas of quantum computing challenge our interpretations of quantum mechanics. It is found that this uncertainty can lead to intrinsic decoherence, and this raises challenges for error correction.

Quantum computing and probability

International Nuclear Information System (INIS)

Ferry, David K

2009-01-01

Over the past two decades, quantum computing has become a popular and promising approach to trying to solve computationally difficult problems. Missing in many descriptions of quantum computing is just how probability enters into the process. Here, we discuss some simple examples of how uncertainty and probability enter, and how this and the ideas of quantum computing challenge our interpretations of quantum mechanics. It is found that this uncertainty can lead to intrinsic decoherence, and this raises challenges for error correction. (viewpoint)

[Biometric bases: basic concepts of probability calculation].

Science.gov (United States)

Dinya, E

1998-04-26

The author gives or outline of the basic concepts of probability theory. The bases of the event algebra, definition of the probability, the classical probability model and the random variable are presented.

Pre-aggregation for Probability Distributions

DEFF Research Database (Denmark)

Timko, Igor; Dyreson, Curtis E.; Pedersen, Torben Bach

Motivated by the increasing need to analyze complex uncertain multidimensional data (e.g., in order to optimize and personalize location-based services), this paper proposes novel types of {\\em probabilistic} OLAP queries that operate on aggregate values that are probability distributions...... and the techniques to process these queries. The paper also presents the methods for computing the probability distributions, which enables pre-aggregation, and for using the pre-aggregated distributions for further aggregation. In order to achieve good time and space efficiency, the methods perform approximate...... multidimensional data analysis that is considered in this paper (i.e., approximate processing of probabilistic OLAP queries over probability distributions)....

Quando um primitivo é como um orbe? Quando um primitivo é como um orbe?

Directory of Open Access Journals (Sweden)

J. Hillis Miller

2008-04-01

Full Text Available Minhas estratégias de analise textual se tornarão mais ou menos evidentes na leitura que se segue. Sua proveniência deveriam tornar-se & cia. 0 ensaio foi inicialmente pensado come parte do livro The Linguistic Moment (Princeton: Princeton University Press, 1985. Aqui, como no livro, minha preocupação maior e com aqueles momentos em poemas em que a poesia como meio de comunicação constitui problema. Interessa-me particularmente a forma pela qual as fronteiras entre a linguagem conceitual e a figurative se tornam pouco visiveis no poema "A Primitive like an Orb", da última fase da poesia de Wallace Stevens.

Contributions to quantum probability

International Nuclear Information System (INIS)

Fritz, Tobias

2010-01-01

Chapter 1: On the existence of quantum representations for two dichotomic measurements. Under which conditions do outcome probabilities of measurements possess a quantum-mechanical model? This kind of problem is solved here for the case of two dichotomic von Neumann measurements which can be applied repeatedly to a quantum system with trivial dynamics. The solution uses methods from the theory of operator algebras and the theory of moment problems. The ensuing conditions reveal surprisingly simple relations between certain quantum-mechanical probabilities. It also shown that generally, none of these relations holds in general probabilistic models. This result might facilitate further experimental discrimination between quantum mechanics and other general probabilistic theories. Chapter 2: Possibilistic Physics. I try to outline a framework for fundamental physics where the concept of probability gets replaced by the concept of possibility. Whereas a probabilistic theory assigns a state-dependent probability value to each outcome of each measurement, a possibilistic theory merely assigns one of the state-dependent labels ''possible to occur'' or ''impossible to occur'' to each outcome of each measurement. It is argued that Spekkens' combinatorial toy theory of quantum mechanics is inconsistent in a probabilistic framework, but can be regarded as possibilistic. Then, I introduce the concept of possibilistic local hidden variable models and derive a class of possibilistic Bell inequalities which are violated for the possibilistic Popescu-Rohrlich boxes. The chapter ends with a philosophical discussion on possibilistic vs. probabilistic. It can be argued that, due to better falsifiability properties, a possibilistic theory has higher predictive power than a probabilistic one. Chapter 3: The quantum region for von Neumann measurements with postselection. It is determined under which conditions a probability distribution on a finite set can occur as the outcome

Probability inequalities for decomposition integrals

Czech Academy of Sciences Publication Activity Database

Agahi, H.; Mesiar, Radko

2017-01-01

Roč. 315, č. 1 (2017), s. 240-248 ISSN 0377-0427 Institutional support: RVO:67985556 Keywords : Decomposition integral * Superdecomposition integral * Probability inequalities Subject RIV: BA - General Mathematics OBOR OECD: Statistics and probability Impact factor: 1.357, year: 2016 http://library.utia.cas.cz/separaty/2017/E/mesiar-0470959.pdf

Probability, conditional probability and complementary cumulative distribution functions in performance assessment for radioactive waste disposal

International Nuclear Information System (INIS)

Helton, J.C.

1996-03-01

A formal description of the structure of several recent performance assessments (PAs) for the Waste Isolation Pilot Plant (WIPP) is given in terms of the following three components: a probability space (S st , S st , p st ) for stochastic uncertainty, a probability space (S su , S su , p su ) for subjective uncertainty and a function (i.e., a random variable) defined on the product space associated with (S st , S st , p st ) and (S su , S su , p su ). The explicit recognition of the existence of these three components allows a careful description of the use of probability, conditional probability and complementary cumulative distribution functions within the WIPP PA. This usage is illustrated in the context of the U.S. Environmental Protection Agency's standard for the geologic disposal of radioactive waste (40 CFR 191, Subpart B). The paradigm described in this presentation can also be used to impose a logically consistent structure on PAs for other complex systems

Probability, conditional probability and complementary cumulative distribution functions in performance assessment for radioactive waste disposal

International Nuclear Information System (INIS)

Helton, J.C.

1996-01-01

A formal description of the structure of several recent performance assessments (PAs) for the Waste Isolation Pilot Plant (WIPP) is given in terms of the following three components: a probability space (S st , L st , P st ) for stochastic uncertainty, a probability space (S su , L su , P su ) for subjective uncertainty and a function (i.e., a random variable) defined on the product space associated with (S st , L st , P st ) and (S su , L su , P su ). The explicit recognition of the existence of these three components allows a careful description of the use of probability, conditional probability and complementary cumulative distribution functions within the WIPP PA. This usage is illustrated in the context of the US Environmental Protection Agency's standard for the geologic disposal of radioactive waste (40 CFR 191, Subpart B). The paradigm described in this presentation can also be used to impose a logically consistent structure on PAs for other complex systems

Void probability scaling in hadron nucleus interactions

International Nuclear Information System (INIS)

Ghosh, Dipak; Deb, Argha; Bhattacharyya, Swarnapratim; Ghosh, Jayita; Bandyopadhyay, Prabhat; Das, Rupa; Mukherjee, Sima

2002-01-01

Heygi while investigating with the rapidity gap probability (that measures the chance of finding no particle in the pseudo-rapidity interval Δη) found that a scaling behavior in the rapidity gap probability has a close correspondence with the scaling of a void probability in galaxy correlation study. The main aim in this paper is to study the scaling behavior of the rapidity gap probability

La transparencia como objetivo del desarrollo sostenible

OpenAIRE

Juan José Gilli

2017-01-01

El presente trabajo tiene por propósito precisar el significado de la transparencia en la gestión pública como una exigencia de carácter ético relacionada con la información que los agentes deben dar en el ámbito sus funciones, reconociendo al ciudadano como el dueño de la información que producen y guardan. La transparencia tiene un especial valor como herramienta para combatir la corrupción y, de esa forma, contribuir a la meta de lograr instituciones inclusivas y efectivas para el desarrol...

A montagem cinematográfica como ato criativo

Directory of Open Access Journals (Sweden)

Maria Dora Genis Mourão

2006-06-01

Full Text Available O foco deste trabalho é refletir sobre a montagem cinematográfica como ato criativo, não a montagem pensada como simples agenciadora de planos, mas como criadora de sentidos. É na maneira como o cinema articula e aproxima as imagens e os sons que verificamos sua transformação em discurso. Criam-se novos sentidos, uma nova lógica onde os significados não são transparentes, nascida da associação de fragmentos. Justapõem-se duas realidades: a da vida propriamente dita e a do filme, a do discurso e, ainda dentro do filme, a justaposição de planos determinando novas leituras das Imagens. Partindo dos princípios da teoria da montagem cinematográfica de S. M. Eisenstein, faremos um rápido panorama de como o cinema, no decorrer de sua história, foi influenciado pelos conceitos desenvolvidos em sua teoria.

Paraconsistent Probabilities: Consistency, Contradictions and Bayes’ Theorem

Directory of Open Access Journals (Sweden)

Juliana Bueno-Soler

2016-09-01

Full Text Available This paper represents the first steps towards constructing a paraconsistent theory of probability based on the Logics of Formal Inconsistency (LFIs. We show that LFIs encode very naturally an extension of the notion of probability able to express sophisticated probabilistic reasoning under contradictions employing appropriate notions of conditional probability and paraconsistent updating, via a version of Bayes’ theorem for conditionalization. We argue that the dissimilarity between the notions of inconsistency and contradiction, one of the pillars of LFIs, plays a central role in our extended notion of probability. Some critical historical and conceptual points about probability theory are also reviewed.

Exploring non-signalling polytopes with negative probability

International Nuclear Information System (INIS)

Oas, G; Barros, J Acacio de; Carvalhaes, C

2014-01-01

Bipartite and tripartite EPR–Bell type systems are examined via joint quasi-probability distributions where probabilities are permitted to be negative. It is shown that such distributions exist only when the no-signalling condition is satisfied. A characteristic measure, the probability mass, is introduced and, via its minimization, limits the number of quasi-distributions describing a given marginal probability distribution. The minimized probability mass is shown to be an alternative way to characterize non-local systems. Non-signalling polytopes for two to eight settings in the bipartite scenario are examined and compared to prior work. Examining perfect cloning of non-local systems within the tripartite scenario suggests defining two categories of signalling. It is seen that many properties of non-local systems can be efficiently described by quasi-probability theory. (paper)

Fundamentals of applied probability and random processes

CERN Document Server

Ibe, Oliver

2005-01-01

This book is based on the premise that engineers use probability as a modeling tool, and that probability can be applied to the solution of engineering problems. Engineers and students studying probability and random processes also need to analyze data, and thus need some knowledge of statistics. This book is designed to provide students with a thorough grounding in probability and stochastic processes, demonstrate their applicability to real-world problems, and introduce the basics of statistics. The book''s clear writing style and homework problems make it ideal for the classroom or for self-study.* Good and solid introduction to probability theory and stochastic processes * Logically organized; writing is presented in a clear manner * Choice of topics is comprehensive within the area of probability * Ample homework problems are organized into chapter sections

The enigma of probability and physics

International Nuclear Information System (INIS)

Mayants, L.

1984-01-01

This volume contains a coherent exposition of the elements of two unique sciences: probabilistics (science of probability) and probabilistic physics (application of probabilistics to physics). Proceeding from a key methodological principle, it starts with the disclosure of the true content of probability and the interrelation between probability theory and experimental statistics. This makes is possible to introduce a proper order in all the sciences dealing with probability and, by conceiving the real content of statistical mechanics and quantum mechanics in particular, to construct both as two interconnected domains of probabilistic physics. Consistent theories of kinetics of physical transformations, decay processes, and intramolecular rearrangements are also outlined. The interrelation between the electromagnetic field, photons, and the theoretically discovered subatomic particle 'emon' is considered. Numerous internal imperfections of conventional probability theory, statistical physics, and quantum physics are exposed and removed - quantum physics no longer needs special interpretation. EPR, Bohm, and Bell paradoxes are easily resolved, among others. (Auth.)

Pilot study of once-daily simplification therapy with abacavir/lamivudine/zidovudine and efavirenz for treatment of HIV-1 infection.

Science.gov (United States)

Ruane, Peter; Lang, Joseph; DeJesus, Edwin; Berger, Daniel S; Dretler, Robin; Rodriguez, Allan; Ward, Douglas J; Lim, Michael L; Liao, Qiming; Reddy, Sunila; Clair, Marty St; Vila, Tania; Shaefer, Mark S

2006-01-01

The purpose of this pilot study was to explore the efficacy and safety of the abacavir/lamivudine/zidovudine fixed-dose combination tablet administered as two tablets once daily (qd) versus one tablet twice daily (bid) in combination with efavirenz (EFV). This was a prospective, randomized, open-label, multicenter study with a 24-week treatment period in 7 outpatient HIV clinics in the United States. Patients currently receiving an initial regimen of abacavir/lamivudine/zidovudine bid plus EFV qd for at least 6 months with HIV-1 RNA or = 200 cells/mm3 were eligible. Thirty-six patients enrolled, and 35 (97%) completed the study. Participants were randomized to switch to 2 tablets of abacavir/lamivudine/zidovudine qd plus EFV qd (QD arm) or continue current treatment (BID arm) for 24 weeks. Efficacy, safety, and adherence were evaluated. Median baseline CD4+ cell count was 521 cells/mm3. At week 24, HIV-1 RNA or = 0.29 to +0.18, p = 1.000). At week 24, median CD4+ cell count change from baseline was +26 cells/mm3 for the QD arm and -39 cells/mm3 for BID arm. One patient randomized to the QD arm met virologic failure criteria (confirmed HIV-1 RNA >120 copies/mL) at week 20 and viral genotype showed M184V. After failure, this patient revealed he never took EFV throughout the entire study after randomization, effectively receiving only abacavir/lamivudine/zidovudine qd alone. Median adherence was slightly higher in the QD arm, although both arms had broad variability and overlapping interquartile ranges. Adverse events were infrequent and occurred with similar frequency between arms; treatment-related adverse events were abdominal pain, flatulence, nausea, headache, and abnormal dreams (1 patient [3%] for each adverse event). No patients withdrew due to adverse events, and no abacavir hypersensitivity reactions were reported. In this pilot study of patients suppressed on abacavir/lamivudine/zidovudine bid plus EFV, 94% of participants switching to abacavir

F.Y. Edgeworth’s Treatise on Probabilities

OpenAIRE

Alberto Baccini

2007-01-01

Probability theory has a central role in Edgeworth’s thought; this paper examines the philosophical foundation of the theory. Starting from a frequentist position, Edgeworth introduced some innovations on the definition of primitive probabilities. He distinguished between primitive probabilities based on experience of statistical evidence, and primitive a priori probabilities based on a more general and less precise kind of experience, inherited by the human race through evolution. Given prim...

Quantitative analysis of the effect of zidovudine, efavirenz, and ritonavir on insulin aggregation by multivariate curve resolution alternating least squares of infrared spectra

International Nuclear Information System (INIS)

Martí-Aluja, Idoia; Ruisánchez, Itziar; Larrechi, M. Soledad

2013-01-01

Highlights: ► The structure of insulin can be changed via interaction with antiretroviral drugs. ► The chemical interaction promotes the formation of aggregates. ► This drug effect was evaluated by MCR-ALS coupled to IR spectroscopy. ► Formation of aggregates was favourable if drugs were able to form hydrogen bonds. ► Higher drug concentrations favoured formation of amorphous aggregates. - Abstract: Quantification of the effect of antiretroviral drugs on the insulin aggregation process is an important area of research due to the serious metabolic diseases observed in AIDS patients after prolonged treatment with these drugs. In this work, multivariate curve resolution alternating least squares (MCR-ALS) was applied to infrared monitoring of the insulin aggregation process in the presence of three antiretroviral drugs to quantify their effect. To evidence concentration dependence in this process, mixtures at two different insulin:drug molar ratios were used. The interaction between insulin and each drug was analysed by 1 H NMR spectroscopy. In all cases, the aggregation process was monitored during 45 min by infrared spectroscopy. The aggregates were further characterised by scanning electron microscopy (SEM). MCR-ALS provided the spectral and concentration profiles of the different insulin–drug conformations that are involved in the process. Their feasible band boundaries were calculated using the MCR-BANDS methodology. The kinetic profiles describe the aggregation pathway and the spectral profiles characterise the conformations involved. The retrieved results show that each of the three drugs modifies insulin conformation in a different way, promoting the formation of aggregates. Ritonavir shows the strongest promotion of aggregation, followed by efavirenz and zidovudine. In the studied concentration range, concentration dependence was only observed for zidovudine, with shorter aggregation time obtained as the amount of zidovudine increased. This factor

Tuberculosis como enfermedad ocupacional Tuberculosis as occupational disease

OpenAIRE

Alberto Mendoza-Ticona

2012-01-01

Existe evidencia suficiente para declarar a la tuberculosis como enfermedad ocupacional en diversos profesionales especialmente entre los trabajadores de salud. En el Perú están normados y reglamentados los derechos laborales inherentes a la tuberculosis como enfermedad ocupacional, como la cobertura por discapacidad temporal o permanente. Sin embargo, estos derechos aún no han sido suficientemente socializados. En este trabajo se presenta información sobre el riesgo de adquirir tuberculosis ...

Approximation methods in probability theory

CERN Document Server

Čekanavičius, Vydas

2016-01-01

This book presents a wide range of well-known and less common methods used for estimating the accuracy of probabilistic approximations, including the Esseen type inversion formulas, the Stein method as well as the methods of convolutions and triangle function. Emphasising the correct usage of the methods presented, each step required for the proofs is examined in detail. As a result, this textbook provides valuable tools for proving approximation theorems. While Approximation Methods in Probability Theory will appeal to everyone interested in limit theorems of probability theory, the book is particularly aimed at graduate students who have completed a standard intermediate course in probability theory. Furthermore, experienced researchers wanting to enlarge their toolkit will also find this book useful.

Introduction to imprecise probabilities

CERN Document Server

Augustin, Thomas; de Cooman, Gert; Troffaes, Matthias C M

2014-01-01

In recent years, the theory has become widely accepted and has been further developed, but a detailed introduction is needed in order to make the material available and accessible to a wide audience. This will be the first book providing such an introduction, covering core theory and recent developments which can be applied to many application areas. All authors of individual chapters are leading researchers on the specific topics, assuring high quality and up-to-date contents. An Introduction to Imprecise Probabilities provides a comprehensive introduction to imprecise probabilities, includin

Classic Problems of Probability

CERN Document Server

Gorroochurn, Prakash

2012-01-01

"A great book, one that I will certainly add to my personal library."—Paul J. Nahin, Professor Emeritus of Electrical Engineering, University of New Hampshire Classic Problems of Probability presents a lively account of the most intriguing aspects of statistics. The book features a large collection of more than thirty classic probability problems which have been carefully selected for their interesting history, the way they have shaped the field, and their counterintuitive nature. From Cardano's 1564 Games of Chance to Jacob Bernoulli's 1713 Golden Theorem to Parrondo's 1996 Perplexin

A Imagem como Ruína

Directory of Open Access Journals (Sweden)

Míriam Volpe

2001-12-01

Full Text Available O dialogismo ente o filme Citizen Kane, de Orson Welles, e o poema “Kubla Khan”, de S.T. Coleridgé, é analisado, sendo evidenciados não só o tema em comum – o mito do Paraíso perdido – como também a similariedade na organização do disurso na justaposição das images, como fragmentos da memória a serem preservados.

El Derecho como práctica y como discurso. La perspectiva de la persona como garantía de objetividad y razonabilidad en la interpretación

Directory of Open Access Journals (Sweden)

PILAR ZAMBRANO

2009-01-01

Full Text Available El trabajo se propone ofrecer una comprensión tanto de los orígenes como de los límites de la problematicidad de la interpretación jurídica -en particular, aunque no de modo único, de la interpretación constitucional-, focalizada en la estructura intencional del Derecho como discurso escrito y como práctica social. En cuanto discurso, el Derecho se concibe como un conjunto de "actos del habla"; en tanto práctica social, la comprensibilidad del Derecho se vincula a los fines o a las intenciones que se proponen sus participantes y que lo distinguen de otras prácticas sociales. Se concluye desde esta doble perspectiva que, lejos de ser un método entre otros, la interpretación teleológica es la estructura formal indisponible de toda interpretación jurídica. Sobre esta base se intenta mostrar que, aunque la proyección teleológica del Derecho opere como causal de la problematicidad de la interpretación jurídica, al mismo tiempo se constituye en el límite o marco para la dimensión creativa de la interpretación. A partir de aquí se defiende la tesis de que la problematicidad de la interpretación jurídica no es sinónimo de arbitrariedad en el Derecho constitucionalizado, al menos si se asumen dos postulados. Primero, que la abstracción del lenguaje jurídico es indeterminación, pero no vaguedad. Segundo, que los fines últimos del Derecho se ligan a una concepción de persona objetiva -metafísica, no política-.

Contributions to quantum probability

Energy Technology Data Exchange (ETDEWEB)

Fritz, Tobias

2010-06-25

Chapter 1: On the existence of quantum representations for two dichotomic measurements. Under which conditions do outcome probabilities of measurements possess a quantum-mechanical model? This kind of problem is solved here for the case of two dichotomic von Neumann measurements which can be applied repeatedly to a quantum system with trivial dynamics. The solution uses methods from the theory of operator algebras and the theory of moment problems. The ensuing conditions reveal surprisingly simple relations between certain quantum-mechanical probabilities. It also shown that generally, none of these relations holds in general probabilistic models. This result might facilitate further experimental discrimination between quantum mechanics and other general probabilistic theories. Chapter 2: Possibilistic Physics. I try to outline a framework for fundamental physics where the concept of probability gets replaced by the concept of possibility. Whereas a probabilistic theory assigns a state-dependent probability value to each outcome of each measurement, a possibilistic theory merely assigns one of the state-dependent labels ''possible to occur'' or ''impossible to occur'' to each outcome of each measurement. It is argued that Spekkens' combinatorial toy theory of quantum mechanics is inconsistent in a probabilistic framework, but can be regarded as possibilistic. Then, I introduce the concept of possibilistic local hidden variable models and derive a class of possibilistic Bell inequalities which are violated for the possibilistic Popescu-Rohrlich boxes. The chapter ends with a philosophical discussion on possibilistic vs. probabilistic. It can be argued that, due to better falsifiability properties, a possibilistic theory has higher predictive power than a probabilistic one. Chapter 3: The quantum region for von Neumann measurements with postselection. It is determined under which conditions a probability distribution on a

Assessing the clinical probability of pulmonary embolism

International Nuclear Information System (INIS)

Miniati, M.; Pistolesi, M.

2001-01-01

Clinical assessment is a cornerstone of the recently validated diagnostic strategies for pulmonary embolism (PE). Although the diagnostic yield of individual symptoms, signs, and common laboratory tests is limited, the combination of these variables, either by empirical assessment or by a prediction rule, can be used to express a clinical probability of PE. The latter may serve as pretest probability to predict the probability of PE after further objective testing (posterior or post-test probability). Over the last few years, attempts have been made to develop structured prediction models for PE. In a Canadian multicenter prospective study, the clinical probability of PE was rated as low, intermediate, or high according to a model which included assessment of presenting symptoms and signs, risk factors, and presence or absence of an alternative diagnosis at least as likely as PE. Recently, a simple clinical score was developed to stratify outpatients with suspected PE into groups with low, intermediate, or high clinical probability. Logistic regression was used to predict parameters associated with PE. A score ≤ 4 identified patients with low probability of whom 10% had PE. The prevalence of PE in patients with intermediate (score 5-8) and high probability (score ≥ 9) was 38 and 81%, respectively. As opposed to the Canadian model, this clinical score is standardized. The predictor variables identified in the model, however, were derived from a database of emergency ward patients. This model may, therefore, not be valid in assessing the clinical probability of PE in inpatients. In the PISA-PED study, a clinical diagnostic algorithm was developed which rests on the identification of three relevant clinical symptoms and on their association with electrocardiographic and/or radiographic abnormalities specific for PE. Among patients who, according to the model, had been rated as having a high clinical probability, the prevalence of proven PE was 97%, while it was 3

Using Playing Cards to Differentiate Probability Interpretations

Science.gov (United States)

López Puga, Jorge

2014-01-01

The aprioristic (classical, naïve and symmetric) and frequentist interpretations of probability are commonly known. Bayesian or subjective interpretation of probability is receiving increasing attention. This paper describes an activity to help students differentiate between the three types of probability interpretations.

LAS CIUDADES COMO TERRITORIO DE LA EDUCACIÓN INTEGRAL

Directory of Open Access Journals (Sweden)

Maria Silvia Serra

2015-12-01

Full Text Available RESUMEN: Habitar las ciudades es un proceso en el que se encuentran anudadas cuestiones materiales y simbólicas. Este lazo debe ser atendido y puesto en valor en términos históricos y culturales ya que forma parte de nuestro aprendizaje como sujetos urbanos. En este sentido, tal como afirma Andreas Huyssen (2002: 191 "...la ciudad funciona como un tipo de prisma" que permite "enfocar" una multiplicidad de temáticas que no están solo ligadas al urbanismo o a la arquitectura, sino también a experiencias culturales y construcciones simbólicas que articulan el hecho concreto de vivir en las ciudades. Es así que, siguiendo a este autor, podemos afirmar que la ciudad es un texto que puede ser leído como un verdadero espacio de signos. Una casa, un barrio, un edificio, los espacios públicos, las calles y veredas, los monumentos son reservorios de un tiempo y una memoria que requieren de una multiplicidad de lecturas para transformarse en escenarios de aprendizajes integradores. Cuestionar a la ciudad como territorio de la educación integral así como reconocer las cuestiones centrales que se ponen a prueba cuando esto se postula como una política pública son los objetivos principales del presente artículo, para lo cual proponemos un recorrido a partir de considerar conceptos nodales como los de educación integral y pedagogía urbana.

Towards a Categorical Account of Conditional Probability

Directory of Open Access Journals (Sweden)

Robert Furber

2015-11-01

Full Text Available This paper presents a categorical account of conditional probability, covering both the classical and the quantum case. Classical conditional probabilities are expressed as a certain "triangle-fill-in" condition, connecting marginal and joint probabilities, in the Kleisli category of the distribution monad. The conditional probabilities are induced by a map together with a predicate (the condition. The latter is a predicate in the logic of effect modules on this Kleisli category. This same approach can be transferred to the category of C*-algebras (with positive unital maps, whose predicate logic is also expressed in terms of effect modules. Conditional probabilities can again be expressed via a triangle-fill-in property. In the literature, there are several proposals for what quantum conditional probability should be, and also there are extra difficulties not present in the classical case. At this stage, we only describe quantum systems with classical parametrization.

Probability, conditional probability and complementary cumulative distribution functions in performance assessment for radioactive waste disposal

Energy Technology Data Exchange (ETDEWEB)

Helton, J.C. [Arizona State Univ., Tempe, AZ (United States)

1996-03-01

A formal description of the structure of several recent performance assessments (PAs) for the Waste Isolation Pilot Plant (WIPP) is given in terms of the following three components: a probability space (S{sub st}, S{sub st}, p{sub st}) for stochastic uncertainty, a probability space (S{sub su}, S{sub su}, p{sub su}) for subjective uncertainty and a function (i.e., a random variable) defined on the product space associated with (S{sub st}, S{sub st}, p{sub st}) and (S{sub su}, S{sub su}, p{sub su}). The explicit recognition of the existence of these three components allows a careful description of the use of probability, conditional probability and complementary cumulative distribution functions within the WIPP PA. This usage is illustrated in the context of the U.S. Environmental Protection Agency`s standard for the geologic disposal of radioactive waste (40 CFR 191, Subpart B). The paradigm described in this presentation can also be used to impose a logically consistent structure on PAs for other complex systems.

Sensitivity of probability-of-failure estimates with respect to probability of detection curve parameters

Energy Technology Data Exchange (ETDEWEB)

Garza, J. [University of Texas at San Antonio, Mechanical Engineering, 1 UTSA circle, EB 3.04.50, San Antonio, TX 78249 (United States); Millwater, H., E-mail: harry.millwater@utsa.edu [University of Texas at San Antonio, Mechanical Engineering, 1 UTSA circle, EB 3.04.50, San Antonio, TX 78249 (United States)

2012-04-15

A methodology has been developed and demonstrated that can be used to compute the sensitivity of the probability-of-failure (POF) with respect to the parameters of inspection processes that are simulated using probability of detection (POD) curves. The formulation is such that the probabilistic sensitivities can be obtained at negligible cost using sampling methods by reusing the samples used to compute the POF. As a result, the methodology can be implemented for negligible cost in a post-processing non-intrusive manner thereby facilitating implementation with existing or commercial codes. The formulation is generic and not limited to any specific random variables, fracture mechanics formulation, or any specific POD curve as long as the POD is modeled parametrically. Sensitivity estimates for the cases of different POD curves at multiple inspections, and the same POD curves at multiple inspections have been derived. Several numerical examples are presented and show excellent agreement with finite difference estimates with significant computational savings. - Highlights: Black-Right-Pointing-Pointer Sensitivity of the probability-of-failure with respect to the probability-of-detection curve. Black-Right-Pointing-Pointer The sensitivities are computed with negligible cost using Monte Carlo sampling. Black-Right-Pointing-Pointer The change in the POF due to a change in the POD curve parameters can be easily estimated.

Sensitivity of probability-of-failure estimates with respect to probability of detection curve parameters

International Nuclear Information System (INIS)

Garza, J.; Millwater, H.

2012-01-01

A methodology has been developed and demonstrated that can be used to compute the sensitivity of the probability-of-failure (POF) with respect to the parameters of inspection processes that are simulated using probability of detection (POD) curves. The formulation is such that the probabilistic sensitivities can be obtained at negligible cost using sampling methods by reusing the samples used to compute the POF. As a result, the methodology can be implemented for negligible cost in a post-processing non-intrusive manner thereby facilitating implementation with existing or commercial codes. The formulation is generic and not limited to any specific random variables, fracture mechanics formulation, or any specific POD curve as long as the POD is modeled parametrically. Sensitivity estimates for the cases of different POD curves at multiple inspections, and the same POD curves at multiple inspections have been derived. Several numerical examples are presented and show excellent agreement with finite difference estimates with significant computational savings. - Highlights: ► Sensitivity of the probability-of-failure with respect to the probability-of-detection curve. ►The sensitivities are computed with negligible cost using Monte Carlo sampling. ► The change in the POF due to a change in the POD curve parameters can be easily estimated.

PROBABILITY CALIBRATION BY THE MINIMUM AND MAXIMUM PROBABILITY SCORES IN ONE-CLASS BAYES LEARNING FOR ANOMALY DETECTION

Data.gov (United States)

National Aeronautics and Space Administration — PROBABILITY CALIBRATION BY THE MINIMUM AND MAXIMUM PROBABILITY SCORES IN ONE-CLASS BAYES LEARNING FOR ANOMALY DETECTION GUICHONG LI, NATHALIE JAPKOWICZ, IAN HOFFMAN,...

Collective probabilities algorithm for surface hopping calculations

International Nuclear Information System (INIS)

Bastida, Adolfo; Cruz, Carlos; Zuniga, Jose; Requena, Alberto

2003-01-01

General equations that transition probabilities of the hopping algorithms in surface hopping calculations must obey to assure the equality between the average quantum and classical populations are derived. These equations are solved for two particular cases. In the first it is assumed that probabilities are the same for all trajectories and that the number of hops is kept to a minimum. These assumptions specify the collective probabilities (CP) algorithm, for which the transition probabilities depend on the average populations for all trajectories. In the second case, the probabilities for each trajectory are supposed to be completely independent of the results from the other trajectories. There is, then, a unique solution of the general equations assuring that the transition probabilities are equal to the quantum population of the target state, which is referred to as the independent probabilities (IP) algorithm. The fewest switches (FS) algorithm developed by Tully is accordingly understood as an approximate hopping algorithm which takes elements from the accurate CP and IP solutions. A numerical test of all these hopping algorithms is carried out for a one-dimensional two-state problem with two avoiding crossings which shows the accuracy and computational efficiency of the collective probabilities algorithm proposed, the limitations of the FS algorithm and the similarity between the results offered by the IP algorithm and those obtained with the Ehrenfest method

Foundations of the theory of probability

CERN Document Server

Kolmogorov, AN

2018-01-01

This famous little book remains a foundational text for the understanding of probability theory, important both to students beginning a serious study of probability and to historians of modern mathematics. 1956 second edition.

La sangre como espectáculo.

Directory of Open Access Journals (Sweden)

Rubén Darío Buitrón

2015-01-01

Full Text Available El autor asevera que cuando la información es concebida y tratada como una mercancía y no como un bien social, la avidez por el lucro la degenera en productos abyectos donde la sangre es espectáculo que sirve para exacerbar el morbo social, incrementar las ventas y los ingresos publicitarios. Señala que lamentablemente en el Ecuador este tipo de periodismo es una plaga muy bien vendida.

Probability an introduction with statistical applications

CERN Document Server

Kinney, John J

2014-01-01

Praise for the First Edition""This is a well-written and impressively presented introduction to probability and statistics. The text throughout is highly readable, and the author makes liberal use of graphs and diagrams to clarify the theory.""  - The StatisticianThoroughly updated, Probability: An Introduction with Statistical Applications, Second Edition features a comprehensive exploration of statistical data analysis as an application of probability. The new edition provides an introduction to statistics with accessible coverage of reliability, acceptance sampling, confidence intervals, h

Probability Distributome: A Web Computational Infrastructure for Exploring the Properties, Interrelations, and Applications of Probability Distributions.

Science.gov (United States)

Dinov, Ivo D; Siegrist, Kyle; Pearl, Dennis K; Kalinin, Alexandr; Christou, Nicolas

2016-06-01

Probability distributions are useful for modeling, simulation, analysis, and inference on varieties of natural processes and physical phenomena. There are uncountably many probability distributions. However, a few dozen families of distributions are commonly defined and are frequently used in practice for problem solving, experimental applications, and theoretical studies. In this paper, we present a new computational and graphical infrastructure, the Distributome , which facilitates the discovery, exploration and application of diverse spectra of probability distributions. The extensible Distributome infrastructure provides interfaces for (human and machine) traversal, search, and navigation of all common probability distributions. It also enables distribution modeling, applications, investigation of inter-distribution relations, as well as their analytical representations and computational utilization. The entire Distributome framework is designed and implemented as an open-source, community-built, and Internet-accessible infrastructure. It is portable, extensible and compatible with HTML5 and Web2.0 standards (http://Distributome.org). We demonstrate two types of applications of the probability Distributome resources: computational research and science education. The Distributome tools may be employed to address five complementary computational modeling applications (simulation, data-analysis and inference, model-fitting, examination of the analytical, mathematical and computational properties of specific probability distributions, and exploration of the inter-distributional relations). Many high school and college science, technology, engineering and mathematics (STEM) courses may be enriched by the use of modern pedagogical approaches and technology-enhanced methods. The Distributome resources provide enhancements for blended STEM education by improving student motivation, augmenting the classical curriculum with interactive webapps, and overhauling the

Nevirapine and efavirenz elicit different changes in lipid profiles in antiretroviral-therapy-naive patients infected with HIV-1.

Directory of Open Access Journals (Sweden)

Frank van Leth

2004-10-01

Full Text Available BACKGROUND: Patients infected with HIV-1 initiating antiretroviral therapy (ART containing a non-nucleoside reverse transcriptase inhibitor (NNRTI show presumably fewer atherogenic lipid changes than those initiating most ARTs containing a protease inhibitor. We analysed whether lipid changes differed between the two most commonly used NNRTIs, nevirapine (NVP and efavirenz (EFV. METHODS AND FINDINGS: Prospective analysis of lipids and lipoproteins was performed in patients enrolled in the NVP and EFV treatment groups of the 2NN study who remained on allocated treatment during 48 wk of follow-up. Patients were allocated to NVP (n = 417, or EFV (n = 289 in combination with stavudine and lamivudine. The primary endpoint was percentage change over 48 wk in high-density lipoprotein cholesterol (HDL-c, total cholesterol (TC, TC:HDL-c ratio, non-HDL-c, low-density lipoprotein cholesterol, and triglycerides. The increase of HDL-c was significantly larger for patients receiving NVP (42.5% than for patients receiving EFV (33.7%; p = 0.036, while the increase in TC was lower (26.9% and 31.1%, respectively; p = 0.073, resulting in a decrease of the TC:HDL-c ratio for patients receiving NVP (-4.1% and an increase for patients receiving EFV (+5.9%; p < 0.001. The increase of non-HDL-c was smaller for patients receiving NVP (24.7% than for patients receiving EFV (33.6%; p = 0.007, as were the increases of triglycerides (20.1% and 49.0%, respectively; p < 0.001 and low-density lipoprotein cholesterol (35.0% and 40.0%, respectively; p = 0.378. These differences remained, or even increased, after adjusting for changes in HIV-1 RNA and CD4+ cell levels, indicating an effect of the drugs on lipids over and above that which may be explained by suppression of HIV-1 infection. The increases in HDL-c were of the same order of magnitude as those seen with the use of the investigational HDL-c-increasing drugs. CONCLUSION: NVP-containing ART shows larger increases in HDL

Esposas como principais provedoras de renda familiar Esposas como principales proveedoras de la renta familiar Wives as the main household earners

Directory of Open Access Journals (Sweden)

Izabel Guimarães Marri

2007-06-01

Full Text Available Este trabalho procura discutir um aspecto ainda pouco explorado do papel da mulher na formação dos rendimentos familiares, que é a situação na qual as esposas obtêm, no mercado de trabalho, rendimentos superiores aos de seus cônjuges. Além da descrição de características demográficas e socioocupacionais destas mulheres e de seus cônjuges, procura-se discutir as seguintes questões: como algumas das características observadas estão correlacionadas com a probabilidade de as famílias terem as esposas como principais provedoras; a não reversão dos padrões tradicionais de divisão do trabalho, já que a mulher mantém um número de horas muito maior do que seus cônjuges nas tarefas domésticas, mesmo quando é a principal provedora financeira do casal; e os diferenciais no rendimento médio de maridos e esposas provedores e a decomposição deste diferencial entre o que pode ser atribuído às características produtivas de ambos os grupos e o que é geralmente chamado de discriminação.Este trabajo procura discutir un aspecto aún poco explorado del papel de la mujer en la formación de los rendimientos familiares, que es la situación en la cual las esposas obtienen, en el mercado de trabajo, rendimientos superiores a los de sus cónyuges. Además de la descripción de características demográficas y socio-ocupacionales de estas mujeres y de sus cónyuges, se busca discutir los siguientes aspectos: como algunas de las características observadas están correlacionadas con la probabilidad de que las familias tengan a las esposas como principales proveedoras; la no reversión de los estándares tradicionales de división del trabajo, ya que la mujer dedica un número de horas mucho mayor que sus cónyuges a las tareas domésticas, aún cuando es la principal proveedora financiera de la pareja; los diferenciales en el rendimiento promedio de maridos y esposas proveedores y la descomposición de este diferencial entre lo que puede

Transition probability spaces in loop quantum gravity

Science.gov (United States)

Guo, Xiao-Kan

2018-03-01

We study the (generalized) transition probability spaces, in the sense of Mielnik and Cantoni, for spacetime quantum states in loop quantum gravity. First, we show that loop quantum gravity admits the structures of transition probability spaces. This is exemplified by first checking such structures in covariant quantum mechanics and then identifying the transition probability spaces in spin foam models via a simplified version of general boundary formulation. The transition probability space thus defined gives a simple way to reconstruct the discrete analog of the Hilbert space of the canonical theory and the relevant quantum logical structures. Second, we show that the transition probability space and in particular the spin foam model are 2-categories. Then we discuss how to realize in spin foam models two proposals by Crane about the mathematical structures of quantum gravity, namely, the quantum topos and causal sites. We conclude that transition probability spaces provide us with an alternative framework to understand various foundational questions of loop quantum gravity.

Bayesian Probability Theory

Science.gov (United States)

von der Linden, Wolfgang; Dose, Volker; von Toussaint, Udo

2014-06-01

Preface; Part I. Introduction: 1. The meaning of probability; 2. Basic definitions; 3. Bayesian inference; 4. Combinatrics; 5. Random walks; 6. Limit theorems; 7. Continuous distributions; 8. The central limit theorem; 9. Poisson processes and waiting times; Part II. Assigning Probabilities: 10. Transformation invariance; 11. Maximum entropy; 12. Qualified maximum entropy; 13. Global smoothness; Part III. Parameter Estimation: 14. Bayesian parameter estimation; 15. Frequentist parameter estimation; 16. The Cramer-Rao inequality; Part IV. Testing Hypotheses: 17. The Bayesian way; 18. The frequentist way; 19. Sampling distributions; 20. Bayesian vs frequentist hypothesis tests; Part V. Real World Applications: 21. Regression; 22. Inconsistent data; 23. Unrecognized signal contributions; 24. Change point problems; 25. Function estimation; 26. Integral equations; 27. Model selection; 28. Bayesian experimental design; Part VI. Probabilistic Numerical Techniques: 29. Numerical integration; 30. Monte Carlo methods; 31. Nested sampling; Appendixes; References; Index.

Encounter Probability of Individual Wave Height

DEFF Research Database (Denmark)

Liu, Z.; Burcharth, H. F.

1998-01-01

wave height corresponding to a certain exceedence probability within a structure lifetime (encounter probability), based on the statistical analysis of long-term extreme significant wave height. Then the design individual wave height is calculated as the expected maximum individual wave height...... associated with the design significant wave height, with the assumption that the individual wave heights follow the Rayleigh distribution. However, the exceedence probability of such a design individual wave height within the structure lifetime is unknown. The paper presents a method for the determination...... of the design individual wave height corresponding to an exceedence probability within the structure lifetime, given the long-term extreme significant wave height. The method can also be applied for estimation of the number of relatively large waves for fatigue analysis of constructions....

Two-slit experiment: quantum and classical probabilities

International Nuclear Information System (INIS)

Khrennikov, Andrei

2015-01-01

Inter-relation between quantum and classical probability models is one of the most fundamental problems of quantum foundations. Nowadays this problem also plays an important role in quantum technologies, in quantum cryptography and the theory of quantum random generators. In this letter, we compare the viewpoint of Richard Feynman that the behavior of quantum particles cannot be described by classical probability theory with the viewpoint that quantum–classical inter-relation is more complicated (cf, in particular, with the tomographic model of quantum mechanics developed in detail by Vladimir Man'ko). As a basic example, we consider the two-slit experiment, which played a crucial role in quantum foundational debates at the beginning of quantum mechanics (QM). In particular, its analysis led Niels Bohr to the formulation of the principle of complementarity. First, we demonstrate that in complete accordance with Feynman's viewpoint, the probabilities for the two-slit experiment have the non-Kolmogorovian structure, since they violate one of basic laws of classical probability theory, the law of total probability (the heart of the Bayesian analysis). However, then we show that these probabilities can be embedded in a natural way into the classical (Kolmogorov, 1933) probability model. To do this, one has to take into account the randomness of selection of different experimental contexts, the joint consideration of which led Feynman to a conclusion about the non-classicality of quantum probability. We compare this embedding of non-Kolmogorovian quantum probabilities into the Kolmogorov model with well-known embeddings of non-Euclidean geometries into Euclidean space (e.g., the Poincaré disk model for the Lobachvesky plane). (paper)

Handbook of probability theory and applications

CERN Document Server

Rudas, Tamas

2008-01-01

""This is a valuable reference guide for readers interested in gaining a basic understanding of probability theory or its applications in problem solving in the other disciplines.""-CHOICEProviding cutting-edge perspectives and real-world insights into the greater utility of probability and its applications, the Handbook of Probability offers an equal balance of theory and direct applications in a non-technical, yet comprehensive, format. Editor Tamás Rudas and the internationally-known contributors present the material in a manner so that researchers of vari

Computation of the Complex Probability Function

Energy Technology Data Exchange (ETDEWEB)

Trainer, Amelia Jo [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ledwith, Patrick John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-08-22

The complex probability function is important in many areas of physics and many techniques have been developed in an attempt to compute it for some z quickly and e ciently. Most prominent are the methods that use Gauss-Hermite quadrature, which uses the roots of the n^th degree Hermite polynomial and corresponding weights to approximate the complex probability function. This document serves as an overview and discussion of the use, shortcomings, and potential improvements on the Gauss-Hermite quadrature for the complex probability function.

The Probabilities of Unique Events

Science.gov (United States)

2012-08-30

Washington, DC USA Max Lotstein and Phil Johnson-Laird Department of Psychology Princeton University Princeton, NJ USA August 30th 2012...social justice and also participated in antinuclear demonstrations. The participants ranked the probability that Linda is a feminist bank teller as...retorted that such a flagrant violation of the probability calculus was a result of a psychological experiment that obscured the rationality of the

La fatiga como estado motivacional subjetivo

OpenAIRE

D. Cárdenas; J. Conde-González; J.C. Perales

2017-01-01

Actualmente no existe consenso sobre los factores que determinan la aparición de la fatiga. Hay factores que se derivan exclusivamente del esfuerzo físico, otros que dependen del esfuerzo mental que este lleva aparejado, y otros de los resultados de la tarea que se está realizando. Como consecuencia, se han desarrollado diferentes modelos explicativos que pretenden aunar las diferentes razones de su aparición. No obstante, la tendencia actual es entender la fatiga como un estado motivacion...

Risk Factors for Incident Diabetes in a Cohort Taking First-Line Nonnucleoside Reverse Transcriptase Inhibitor-Based Antiretroviral Therapy.

Science.gov (United States)

Karamchand, Sumanth; Leisegang, Rory; Schomaker, Michael; Maartens, Gary; Walters, Lourens; Hislop, Michael; Dave, Joel A; Levitt, Naomi S; Cohen, Karen

2016-03-01

Efavirenz is the preferred nonnucleoside reverse transcriptase inhibitor (NNRTI) in first-line antiretroviral therapy (ART) regimens in low- and middle-income countries, where the prevalence of diabetes is increasing. Randomized control trials have shown mild increases in plasma glucose in participants in the efavirenz arms, but no association has been reported with overt diabetes. We explored the association between efavirenz exposure and incident diabetes in a large Southern African cohort commencing NNRTI-based first-line ART. Our cohort included HIV-infected adults starting NNRTI-based ART in a private sector HIV disease management program from January 2002 to December 2011. Incident diabetes was identified by the initiation of diabetes treatment. Patients with prevalent diabetes were excluded. We included 56,298 patients with 113,297 patient-years of follow-up (PYFU) on first-line ART. The crude incidence of diabetes was 13.24 per 1000 PYFU. Treatment with efavirenz rather than nevirapine was associated with increased risk of developing diabetes (hazard ratio 1.27 (95% confidence interval (CI): 1.10-1.46)) in a multivariate analysis adjusting for age, sex, body mass index, baseline CD4 count, viral load, NRTI backbone, and exposure to other diabetogenic medicines. Zidovudine and stavudine exposure were also associated with an increased risk of developing diabetes. We found that treatment with efavirenz, as well as stavudine and zidovudine, increased the risk of incident diabetes. Interventions to detect and prevent diabetes should be implemented in ART programs, and use of antiretrovirals with lower risk of metabolic complications should be encouraged.

High throughput nonparametric probability density estimation.

Science.gov (United States)

Farmer, Jenny; Jacobs, Donald

2018-01-01

In high throughput applications, such as those found in bioinformatics and finance, it is important to determine accurate probability distribution functions despite only minimal information about data characteristics, and without using human subjectivity. Such an automated process for univariate data is implemented to achieve this goal by merging the maximum entropy method with single order statistics and maximum likelihood. The only required properties of the random variables are that they are continuous and that they are, or can be approximated as, independent and identically distributed. A quasi-log-likelihood function based on single order statistics for sampled uniform random data is used to empirically construct a sample size invariant universal scoring function. Then a probability density estimate is determined by iteratively improving trial cumulative distribution functions, where better estimates are quantified by the scoring function that identifies atypical fluctuations. This criterion resists under and over fitting data as an alternative to employing the Bayesian or Akaike information criterion. Multiple estimates for the probability density reflect uncertainties due to statistical fluctuations in random samples. Scaled quantile residual plots are also introduced as an effective diagnostic to visualize the quality of the estimated probability densities. Benchmark tests show that estimates for the probability density function (PDF) converge to the true PDF as sample size increases on particularly difficult test probability densities that include cases with discontinuities, multi-resolution scales, heavy tails, and singularities. These results indicate the method has general applicability for high throughput statistical inference.

"I Don't Really Understand Probability at All": Final Year Pre-Service Teachers' Understanding of Probability

Science.gov (United States)

Maher, Nicole; Muir, Tracey

2014-01-01

This paper reports on one aspect of a wider study that investigated a selection of final year pre-service primary teachers' responses to four probability tasks. The tasks focused on foundational ideas of probability including sample space, independence, variation and expectation. Responses suggested that strongly held intuitions appeared to…

Probability of spent fuel transportation accidents

International Nuclear Information System (INIS)

McClure, J.D.

1981-07-01

The transported volume of spent fuel, incident/accident experience and accident environment probabilities were reviewed in order to provide an estimate of spent fuel accident probabilities. In particular, the accident review assessed the accident experience for large casks of the type that could transport spent (irradiated) nuclear fuel. This review determined that since 1971, the beginning of official US Department of Transportation record keeping for accidents/incidents, there has been one spent fuel transportation accident. This information, coupled with estimated annual shipping volumes for spent fuel, indicated an estimated annual probability of a spent fuel transport accident of 5 x 10 -7 spent fuel accidents per mile. This is consistent with ordinary truck accident rates. A comparison of accident environments and regulatory test environments suggests that the probability of truck accidents exceeding regulatory test for impact is approximately 10 -9 /mile

Probabilities on Streams and Reflexive Games

Directory of Open Access Journals (Sweden)

Andrew Schumann

2014-01-01

Full Text Available Probability measures on streams (e.g. on hypernumbers and p-adic numbers have been defined. It was shown that these probabilities can be used for simulations of reflexive games. In particular, it can be proved that Aumann's agreement theorem does not hold for these probabilities. Instead of this theorem, there is a statement that is called the reflexion disagreement theorem. Based on this theorem, probabilistic and knowledge conditions can be defined for reflexive games at various reflexion levels up to the infinite level. (original abstract

Uncertainty about probability: a decision analysis perspective

International Nuclear Information System (INIS)

Howard, R.A.

1988-01-01

The issue of how to think about uncertainty about probability is framed and analyzed from the viewpoint of a decision analyst. The failure of nuclear power plants is used as an example. The key idea is to think of probability as describing a state of information on an uncertain event, and to pose the issue of uncertainty in this quantity as uncertainty about a number that would be definitive: it has the property that you would assign it as the probability if you knew it. Logical consistency requires that the probability to assign to a single occurrence in the absence of further information be the mean of the distribution of this definitive number, not the medium as is sometimes suggested. Any decision that must be made without the benefit of further information must also be made using the mean of the definitive number's distribution. With this formulation, they find further that the probability of r occurrences in n exchangeable trials will depend on the first n moments of the definitive number's distribution. In making decisions, the expected value of clairvoyance on the occurrence of the event must be at least as great as that on the definitive number. If one of the events in question occurs, then the increase in probability of another such event is readily computed. This means, in terms of coin tossing, that unless one is absolutely sure of the fairness of a coin, seeing a head must increase the probability of heads, in distinction to usual thought. A numerical example for nuclear power shows that the failure of one plant of a group with a low probability of failure can significantly increase the probability that must be assigned to failure of a second plant in the group

La reforma agraria como factor del desarrollo regional

Directory of Open Access Journals (Sweden)

José Ambrósio Ferreira Neto

2017-01-01

Full Text Available Este trabajo debate la reforma agraria brasilera como instrumento de desarrollo regional, discutiendo la política actual de asentamientos rurales y su importancia en los procesos de interacción con las dinámicas locales y regionales, investigando las transformaciones que esos proyectos pueden provocar en los municipios donde están inmersos. El trabajo toma como punto central de discusión los argumentos de Polanyi sobre los factores de producción, tierra, capital y trabajo, y de Amartya Sen sobre libertad como factor de desarrollo. La discusión emprendida defiende la reforma agraria como forma de conceder oportunidades y una condición de agentes a sus beneficiarios. Argumentamos que el acceso a la tierra, y a los medios de producción, garantiza al trabajador el control sobre su fuerza de trabajo.

Teaching Probability: A Socio-Constructivist Perspective

Science.gov (United States)

Sharma, Sashi

2015-01-01

There is a considerable and rich literature on students' misconceptions in probability. However, less attention has been paid to the development of students' probabilistic thinking in the classroom. This paper offers a sequence, grounded in socio-constructivist perspective for teaching probability.

Default probabilities and default correlations

OpenAIRE

Erlenmaier, Ulrich; Gersbach, Hans

2001-01-01

Starting from the Merton framework for firm defaults, we provide the analytics and robustness of the relationship between default correlations. We show that loans with higher default probabilities will not only have higher variances but also higher correlations between loans. As a consequence, portfolio standard deviation can increase substantially when loan default probabilities rise. This result has two important implications. First, relative prices of loans with different default probabili...

Probability Matching, Fast and Slow

OpenAIRE

Koehler, Derek J.; James, Greta

2014-01-01

A prominent point of contention among researchers regarding the interpretation of probability-matching behavior is whether it represents a cognitively sophisticated, adaptive response to the inherent uncertainty of the tasks or settings in which it is observed, or whether instead it represents a fundamental shortcoming in the heuristics that support and guide human decision making. Put crudely, researchers disagree on whether probability matching is "smart" or "dumb." Here, we consider eviden...

La proyección como proceso y como mecanismo

OpenAIRE

Brusset, Bernard

2001-01-01

La proyección es a la vez un mecanismo elemental testimonio de la fragilidad de la organización defensiva y un proceso cuyo rol es fundamental en el funcionamiento psíquico. En este doble aspecto, la proyección guarda especificidades diferentes en la neurosis y en la psicosis al punto que se las deba considerar como fundamentalmente diferentes? O bien las diferencias de contexto, del nivel del funcionamiento psíquico, de lugar, de función pueden explicar las diferencias clínicas justificando ...

Posterior Probability Matching and Human Perceptual Decision Making.

Directory of Open Access Journals (Sweden)

Richard F Murray

2015-06-01

Full Text Available Probability matching is a classic theory of decision making that was first developed in models of cognition. Posterior probability matching, a variant in which observers match their response probabilities to the posterior probability of each response being correct, is being used increasingly often in models of perception. However, little is known about whether posterior probability matching is consistent with the vast literature on vision and hearing that has developed within signal detection theory. Here we test posterior probability matching models using two tools from detection theory. First, we examine the models' performance in a two-pass experiment, where each block of trials is presented twice, and we measure the proportion of times that the model gives the same response twice to repeated stimuli. We show that at low performance levels, posterior probability matching models give highly inconsistent responses across repeated presentations of identical trials. We find that practised human observers are more consistent across repeated trials than these models predict, and we find some evidence that less practised observers more consistent as well. Second, we compare the performance of posterior probability matching models on a discrimination task to the performance of a theoretical ideal observer that achieves the best possible performance. We find that posterior probability matching is very inefficient at low-to-moderate performance levels, and that human observers can be more efficient than is ever possible according to posterior probability matching models. These findings support classic signal detection models, and rule out a broad class of posterior probability matching models for expert performance on perceptual tasks that range in complexity from contrast discrimination to symmetry detection. However, our findings leave open the possibility that inexperienced observers may show posterior probability matching behaviour, and our methods

Quitina y carboximetilquitosana como agentes desintegrantes

OpenAIRE

Sol A Fernández Monagas; María D Rodríguez Albadalejo; Ofelia Bilbao Revoredo; Olga M Nieto Acosta

1998-01-01

Se realizó un estudio comparativo de la quitina y la carboximetilquitosana como agentes desintegrantes, y se evaluó la influencia ejercida por el método empleado en la elaboración de las tabletas sobre la actividad desintegrante de ambos polímeros. La quitina presentó buenas características como agente desintegrante independientemente del método utilizado en la elaboración de las tabletas, mientras que la actividad desintegrante de la carboximetilquitosana fue afectada por el proceso de granu...

Dibujo infantil como medio de diagnostico

OpenAIRE

González Hernando, Elisa

2015-01-01

Con este documento se pretende demostrar la importancia que tiene el dibujo infantil en el correcto desarrollo integral de las personas. Se estudia la importancia del dibujo y su valor a la hora de utilizarlo como método de diagnóstico ante determinados aspectos que pueden determinar la vida de una persona. En definitiva lo que se desarrolla en este trabajo de Fin de Grado es el papel que juega el dibujo como herramienta para el seguimiento del desarrollo de los individuos centrándonos ...

Filosofia da ciência como ferramenta microeconômica

Directory of Open Access Journals (Sweden)

Fabio Barbieri

2009-06-01

Full Text Available A teoria neoclássica pressupõe conhecimento perfeito. A crítica hayekiana a essa teoria, por sua vez, afirma que esse conhecimento é resultado do processo competitivo e, portanto, não pode ser considerado como dado. O “Problema de Hayek” investiga sob que condições o conhecimento do agente se aproxima dos reais fundamentos de uma economia. A fim de solucionar o “Problema de Hayek”, o nosso artigo utiliza algumas idéias da literatura de metodologia da Ciência, conhecida como teoria do “crescimento do conhecimento” (Popper, Kuhn, Lakatos e outros. Essas idéias são utilizadas para se compreender como evolui o conhecimento dos agentes econômicos, em especial o dos empresários. Estes são vistos como ativos formuladores de teorias empresariais conjecturais criticadas no processo competitivo, não como agentes passivos que maximizam funções já conhecidas da teoria convencional. Utiliza-se a Filosofia da Ciência não para analisar metodologicamente a microeconomia, mas, sim, como ferramenta analítica pertencente à própria teoria econômica.

Multiple-event probability in general-relativistic quantum mechanics

International Nuclear Information System (INIS)

Hellmann, Frank; Mondragon, Mauricio; Perez, Alejandro; Rovelli, Carlo

2007-01-01

We discuss the definition of quantum probability in the context of 'timeless' general-relativistic quantum mechanics. In particular, we study the probability of sequences of events, or multievent probability. In conventional quantum mechanics this can be obtained by means of the 'wave function collapse' algorithm. We first point out certain difficulties of some natural definitions of multievent probability, including the conditional probability widely considered in the literature. We then observe that multievent probability can be reduced to single-event probability, by taking into account the quantum nature of the measuring apparatus. In fact, by exploiting the von-Neumann freedom of moving the quantum/classical boundary, one can always trade a sequence of noncommuting quantum measurements at different times, with an ensemble of simultaneous commuting measurements on the joint system+apparatus system. This observation permits a formulation of quantum theory based only on single-event probability, where the results of the wave function collapse algorithm can nevertheless be recovered. The discussion also bears on the nature of the quantum collapse

Evaluation of probability and hazard in nuclear energy

International Nuclear Information System (INIS)

Novikov, V.Ya.; Romanov, N.L.

1979-01-01

Various methods of evaluation of accident probability on NPP are proposed because of NPP security statistic evaluation unreliability. The conception of subjective probability for quantitative analysis of security and hazard are described. Intrepretation of probability as real faith of an expert is assumed as a basis of the conception. It is suggested to study the event uncertainty in the framework of subjective probability theory which not only permits but demands to take into account expert opinions when evaluating the probability. These subjective expert evaluations effect to a certain extent the calculation of the usual mathematical event probability. The above technique is advantageous to use for consideration of a separate experiment or random event

Current Efavirenz (EFV or ritonavir-boosted lopinavir (LPV/r use correlates with elevate markers of atherosclerosis in HIV-infected subjects in Addis Ababa, Ethiopia.

Directory of Open Access Journals (Sweden)

Rudolph L Gleason

Full Text Available HIV patients on antiretroviral therapy have shown elevated incidence of dyslipidemia, lipodystrophy, and cardiovascular disease (CVD. Most studies, however, focus on cohorts from developed countries, with less data available for these co-morbidities in Ethiopia and sub-Saharan Africa.Adult HIV-negative (n = 36, treatment naïve (n = 51, efavirenz (EFV-treated (n = 91, nevirapine (NVP-treated (n = 95, or ritonavir-boosted lopinavir (LPV/r-treated (n=44 subjects were recruited from Black Lion Hospital in Addis Ababa, Ethiopia. Aortic pressure, augmentation pressure, and pulse wave velocity (PWV were measured via applanation tonometry and carotid intima-media thickness (cIMT and carotid arterial stiffness, and brachial artery flow-mediated dilation (FMD were measured via non-invasive ultrasound. Body mass index, waist-to-hip circumference ratio (WHR, skinfold thickness, and self-reported fat redistribution were used to quantify lipodystrophy. CD4+ cell count, plasma HIV RNA levels, fasting glucose, total-, HDL-, and LDL-cholesterol, triglycerides, hsCRP, sVCAM-1, sICAM-1, leptin and complete blood count were measured.PWV and normalized cIMT were elevate and FMD impaired in EFV- and LPV/r-treated subjects compared to NVP-treated subjects; normalized cIMT was also elevated and FMD impaired in the EFV- and LPV/r-treated subjects compared to treatment-naïve subjects. cIMT was not statistically different across groups. Treated subjects exhibited elevated markers of dyslipidemia, inflammation, and lipodystrophy. PWV was associated with age, current EFV and LPV/r used, heart rate, blood pressure, triglycerides, LDL, and hsCRP, FMD with age, HIV duration, WHR, and glucose, and cIMT with age, current EFV use, skinfold thickness, and blood pressure.Current EFV- or LPV/r-treatment, but not NVP-treatment, correlated with elevated markers of atherosclerosis, which may involve mechanisms distinct from traditional risk factors.

p-adic probability interpretation of Bell's inequality

International Nuclear Information System (INIS)

Khrennikov, A.

1995-01-01

We study the violation of Bell's inequality using a p-adic generalization of the theory of probability. p-adic probability is introduced as a limit of relative frequencies but this limit exists with respect to a p-adic metric. In particular, negative probability distributions are well defined on the basis of the frequency definition. This new type of stochastics can be used to describe hidden-variables distributions of some quantum models. If the hidden variables have a p-adic probability distribution, Bell's inequality is not valid and it is not necessary to discuss the experimental violations of this inequality. ((orig.))

Dynamic SEP event probability forecasts

Science.gov (United States)

Kahler, S. W.; Ling, A.

2015-10-01

The forecasting of solar energetic particle (SEP) event probabilities at Earth has been based primarily on the estimates of magnetic free energy in active regions and on the observations of peak fluxes and fluences of large (≥ M2) solar X-ray flares. These forecasts are typically issued for the next 24 h or with no definite expiration time, which can be deficient for time-critical operations when no SEP event appears following a large X-ray flare. It is therefore important to decrease the event probability forecast with time as a SEP event fails to appear. We use the NOAA listing of major (≥10 pfu) SEP events from 1976 to 2014 to plot the delay times from X-ray peaks to SEP threshold onsets as a function of solar source longitude. An algorithm is derived to decrease the SEP event probabilities with time when no event is observed to reach the 10 pfu threshold. In addition, we use known SEP event size distributions to modify probability forecasts when SEP intensity increases occur below the 10 pfu event threshold. An algorithm to provide a dynamic SEP event forecast, Pd, for both situations of SEP intensities following a large flare is derived.

Swedish earthquakes and acceleration probabilities

International Nuclear Information System (INIS)

Slunga, R.

1979-03-01

A method to assign probabilities to ground accelerations for Swedish sites is described. As hardly any nearfield instrumental data is available we are left with the problem of interpreting macroseismic data in terms of acceleration. By theoretical wave propagation computations the relation between seismic strength of the earthquake, focal depth, distance and ground accelerations are calculated. We found that most Swedish earthquake of the area, the 1904 earthquake 100 km south of Oslo, is an exception and probably had a focal depth exceeding 25 km. For the nuclear power plant sites an annual probability of 10 -5 has been proposed as interesting. This probability gives ground accelerations in the range 5-20 % for the sites. This acceleration is for a free bedrock site. For consistency all acceleration results in this study are given for bedrock sites. When applicating our model to the 1904 earthquake and assuming the focal zone to be in the lower crust we get the epicentral acceleration of this earthquake to be 5-15 % g. The results above are based on an analyses of macrosismic data as relevant instrumental data is lacking. However, the macroseismic acceleration model deduced in this study gives epicentral ground acceleration of small Swedish earthquakes in agreement with existent distant instrumental data. (author)

Modelling the probability of building fires

Directory of Open Access Journals (Sweden)

Vojtěch Barták

2014-12-01

Full Text Available Systematic spatial risk analysis plays a crucial role in preventing emergencies.In the Czech Republic, risk mapping is currently based on the risk accumulationprinciple, area vulnerability, and preparedness levels of Integrated Rescue Systemcomponents. Expert estimates are used to determine risk levels for individualhazard types, while statistical modelling based on data from actual incidents andtheir possible causes is not used. Our model study, conducted in cooperation withthe Fire Rescue Service of the Czech Republic as a model within the Liberec andHradec Králové regions, presents an analytical procedure leading to the creation ofbuilding fire probability maps based on recent incidents in the studied areas andon building parameters. In order to estimate the probability of building fires, aprediction model based on logistic regression was used. Probability of fire calculatedby means of model parameters and attributes of specific buildings can subsequentlybe visualized in probability maps.

Probability theory

CERN Document Server

Dorogovtsev, A Ya; Skorokhod, A V; Silvestrov, D S; Skorokhod, A V

1997-01-01

This book of problems is intended for students in pure and applied mathematics. There are problems in traditional areas of probability theory and problems in the theory of stochastic processes, which has wide applications in the theory of automatic control, queuing and reliability theories, and in many other modern science and engineering fields. Answers to most of the problems are given, and the book provides hints and solutions for more complicated problems.

Trial type probability modulates the cost of antisaccades

Science.gov (United States)

Chiau, Hui-Yan; Tseng, Philip; Su, Jia-Han; Tzeng, Ovid J. L.; Hung, Daisy L.; Muggleton, Neil G.

2011-01-01

The antisaccade task, where eye movements are made away from a target, has been used to investigate the flexibility of cognitive control of behavior. Antisaccades usually have longer saccade latencies than prosaccades, the so-called antisaccade cost. Recent studies have shown that this antisaccade cost can be modulated by event probability. This may mean that the antisaccade cost can be reduced, or even reversed, if the probability of surrounding events favors the execution of antisaccades. The probabilities of prosaccades and antisaccades were systematically manipulated by changing the proportion of a certain type of trial in an interleaved pro/antisaccades task. We aimed to disentangle the intertwined relationship between trial type probabilities and the antisaccade cost with the ultimate goal of elucidating how probabilities of trial types modulate human flexible behaviors, as well as the characteristics of such modulation effects. To this end, we examined whether implicit trial type probability can influence saccade latencies and also manipulated the difficulty of cue discriminability to see how effects of trial type probability would change when the demand on visual perceptual analysis was high or low. A mixed-effects model was applied to the analysis to dissect the factors contributing to the modulation effects of trial type probabilities. Our results suggest that the trial type probability is one robust determinant of antisaccade cost. These findings highlight the importance of implicit probability in the flexibility of cognitive control of behavior. PMID:21543748

Joint probabilities and quantum cognition

International Nuclear Information System (INIS)

Acacio de Barros, J.

2012-01-01

In this paper we discuss the existence of joint probability distributions for quantumlike response computations in the brain. We do so by focusing on a contextual neural-oscillator model shown to reproduce the main features of behavioral stimulus-response theory. We then exhibit a simple example of contextual random variables not having a joint probability distribution, and describe how such variables can be obtained from neural oscillators, but not from a quantum observable algebra.

Joint probabilities and quantum cognition

Energy Technology Data Exchange (ETDEWEB)

Acacio de Barros, J. [Liberal Studies, 1600 Holloway Ave., San Francisco State University, San Francisco, CA 94132 (United States)

2012-12-18

In this paper we discuss the existence of joint probability distributions for quantumlike response computations in the brain. We do so by focusing on a contextual neural-oscillator model shown to reproduce the main features of behavioral stimulus-response theory. We then exhibit a simple example of contextual random variables not having a joint probability distribution, and describe how such variables can be obtained from neural oscillators, but not from a quantum observable algebra.

Probability Issues in without Replacement Sampling

Science.gov (United States)

Joarder, A. H.; Al-Sabah, W. S.

2007-01-01

Sampling without replacement is an important aspect in teaching conditional probabilities in elementary statistics courses. Different methods proposed in different texts for calculating probabilities of events in this context are reviewed and their relative merits and limitations in applications are pinpointed. An alternative representation of…

Selected papers on probability and statistics

CERN Document Server

2009-01-01

This volume contains translations of papers that originally appeared in the Japanese journal Sūgaku. The papers range over a variety of topics in probability theory, statistics, and applications. This volume is suitable for graduate students and research mathematicians interested in probability and statistics.

Probability of Grounding and Collision Events

DEFF Research Database (Denmark)

Pedersen, Preben Terndrup

1996-01-01

To quantify the risks involved in ship traffic, rational criteria for collision and grounding accidents are developed. This implies that probabilities as well as inherent consequences can be analysed and assessed. The presnt paper outlines a method for evaluation of the probability of ship...

Probability of Grounding and Collision Events

DEFF Research Database (Denmark)

Pedersen, Preben Terndrup

1996-01-01

To quantify the risks involved in ship traffic, rational criteria for collision and grounding accidents have to be developed. This implies that probabilities as well as inherent consequences have to be analyzed and assessed.The present notes outline a method for evaluation of the probability...

Eliciting Subjective Probabilities with Binary Lotteries

DEFF Research Database (Denmark)

Harrison, Glenn W.; Martínez-Correa, Jimmy; Swarthout, J. Todd

objective probabilities. Drawing a sample from the same subject population, we find evidence that the binary lottery procedure induces linear utility in a subjective probability elicitation task using the Quadratic Scoring Rule. We also show that the binary lottery procedure can induce direct revelation...

47 CFR 1.1623 - Probability calculation.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 1 2010-10-01 2010-10-01 false Probability calculation. 1.1623 Section 1.1623 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL PRACTICE AND PROCEDURE Random Selection Procedures for Mass Media Services General Procedures § 1.1623 Probability calculation. (a) All calculations shall be...

Orthogonal Algorithm of Logic Probability and Syndrome-Testable Analysis

Institute of Scientific and Technical Information of China (English)

无

1990-01-01

A new method,orthogonal algoritm,is presented to compute the logic probabilities(i.e.signal probabilities)accurately,The transfer properties of logic probabilities are studied first,which are useful for the calculation of logic probability of the circuit with random independent inputs.Then the orthogonal algoritm is described to compute the logic probability of Boolean function realized by a combinational circuit.This algorithm can make Boolean function “ORTHOGONAL”so that the logic probabilities can be easily calculated by summing up the logic probabilities of all orthogonal terms of the Booleam function.

Probability sampling in legal cases: Kansas cellphone users

Science.gov (United States)

Kadane, Joseph B.

2012-10-01

Probability sampling is a standard statistical technique. This article introduces the basic ideas of probability sampling, and shows in detail how probability sampling was used in a particular legal case.

Effects of NMDA receptor antagonists on probability discounting depend on the order of probability presentation.

Science.gov (United States)

Yates, Justin R; Breitenstein, Kerry A; Gunkel, Benjamin T; Hughes, Mallory N; Johnson, Anthony B; Rogers, Katherine K; Shape, Sara M

Risky decision making can be measured using a probability-discounting procedure, in which animals choose between a small, certain reinforcer and a large, uncertain reinforcer. Recent evidence has identified glutamate as a mediator of risky decision making, as blocking the N-methyl-d-aspartate (NMDA) receptor with MK-801 increases preference for a large, uncertain reinforcer. Because the order in which probabilities associated with the large reinforcer can modulate the effects of drugs on choice, the current study determined if NMDA receptor ligands alter probability discounting using ascending and descending schedules. Sixteen rats were trained in a probability-discounting procedure in which the odds against obtaining the large reinforcer increased (n=8) or decreased (n=8) across blocks of trials. Following behavioral training, rats received treatments of the NMDA receptor ligands MK-801 (uncompetitive antagonist; 0, 0.003, 0.01, or 0.03mg/kg), ketamine (uncompetitive antagonist; 0, 1.0, 5.0, or 10.0mg/kg), and ifenprodil (NR2B-selective non-competitive antagonist; 0, 1.0, 3.0, or 10.0mg/kg). Results showed discounting was steeper (indicating increased risk aversion) for rats on an ascending schedule relative to rats on the descending schedule. Furthermore, the effects of MK-801, ketamine, and ifenprodil on discounting were dependent on the schedule used. Specifically, the highest dose of each drug decreased risk taking in rats in the descending schedule, but only MK-801 (0.03mg/kg) increased risk taking in rats on an ascending schedule. These results show that probability presentation order modulates the effects of NMDA receptor ligands on risky decision making. Copyright © 2016 Elsevier Inc. All rights reserved.

Expert estimation of human error probabilities in nuclear power plant operations: a review of probability assessment and scaling

International Nuclear Information System (INIS)

Stillwell, W.G.; Seaver, D.A.; Schwartz, J.P.

1982-05-01

This report reviews probability assessment and psychological scaling techniques that could be used to estimate human error probabilities (HEPs) in nuclear power plant operations. The techniques rely on expert opinion and can be used to estimate HEPs where data do not exist or are inadequate. These techniques have been used in various other contexts and have been shown to produce reasonably accurate probabilities. Some problems do exist, and limitations are discussed. Additional topics covered include methods for combining estimates from multiple experts, the effects of training on probability estimates, and some ideas on structuring the relationship between performance shaping factors and HEPs. Preliminary recommendations are provided along with cautions regarding the costs of implementing the recommendations. Additional research is required before definitive recommendations can be made

Stimulus Probability Effects in Absolute Identification

Science.gov (United States)

Kent, Christopher; Lamberts, Koen

2016-01-01

This study investigated the effect of stimulus presentation probability on accuracy and response times in an absolute identification task. Three schedules of presentation were used to investigate the interaction between presentation probability and stimulus position within the set. Data from individual participants indicated strong effects of…

Probability numeracy and health insurance purchase

NARCIS (Netherlands)

Dillingh, Rik; Kooreman, Peter; Potters, Jan

2016-01-01

This paper provides new field evidence on the role of probability numeracy in health insurance purchase. Our regression results, based on rich survey panel data, indicate that the expenditure on two out of three measures of health insurance first rises with probability numeracy and then falls again.

El anisakis y sus enfermedades como enfermedad profesional

OpenAIRE

Vicente Pardo, José Manuel

2016-01-01

El anisakis es un parásito complejo de los animales marinos. El hombre no es el hospedador adecuado, ya que en él la larva L3 no puede completar su ciclo vital, siendo por tanto un hospedador accidental u ocasional, que se interpone en el ciclo vital del nemátodo, y al que el anisakis le puede causar tanto la parasitación como la alergia, cuando ingiere pescado o cefalópodos crudos o poco cocinados: tales como sushi, sashimi, ceviche gravlax noruego, lomi-lomi hawaiano, así como pescados en e...

Convergence of Transition Probability Matrix in CLVMarkov Models

Science.gov (United States)

Permana, D.; Pasaribu, U. S.; Indratno, S. W.; Suprayogi, S.

2018-04-01

A transition probability matrix is an arrangement of transition probability from one states to another in a Markov chain model (MCM). One of interesting study on the MCM is its behavior for a long time in the future. The behavior is derived from one property of transition probabilty matrix for n steps. This term is called the convergence of the n-step transition matrix for n move to infinity. Mathematically, the convergence of the transition probability matrix is finding the limit of the transition matrix which is powered by n where n moves to infinity. The convergence form of the transition probability matrix is very interesting as it will bring the matrix to its stationary form. This form is useful for predicting the probability of transitions between states in the future. The method usually used to find the convergence of transition probability matrix is through the process of limiting the distribution. In this paper, the convergence of the transition probability matrix is searched using a simple concept of linear algebra that is by diagonalizing the matrix.This method has a higher level of complexity because it has to perform the process of diagonalization in its matrix. But this way has the advantage of obtaining a common form of power n of the transition probability matrix. This form is useful to see transition matrix before stationary. For example cases are taken from CLV model using MCM called Model of CLV-Markov. There are several models taken by its transition probability matrix to find its convergence form. The result is that the convergence of the matrix of transition probability through diagonalization has similarity with convergence with commonly used distribution of probability limiting method.

Probability Theory Plus Noise: Descriptive Estimation and Inferential Judgment.

Science.gov (United States)

Costello, Fintan; Watts, Paul

2018-01-01

We describe a computational model of two central aspects of people's probabilistic reasoning: descriptive probability estimation and inferential probability judgment. This model assumes that people's reasoning follows standard frequentist probability theory, but it is subject to random noise. This random noise has a regressive effect in descriptive probability estimation, moving probability estimates away from normative probabilities and toward the center of the probability scale. This random noise has an anti-regressive effect in inferential judgement, however. These regressive and anti-regressive effects explain various reliable and systematic biases seen in people's descriptive probability estimation and inferential probability judgment. This model predicts that these contrary effects will tend to cancel out in tasks that involve both descriptive estimation and inferential judgement, leading to unbiased responses in those tasks. We test this model by applying it to one such task, described by Gallistel et al. ). Participants' median responses in this task were unbiased, agreeing with normative probability theory over the full range of responses. Our model captures the pattern of unbiased responses in this task, while simultaneously explaining systematic biases away from normatively correct probabilities seen in other tasks. Copyright © 2018 Cognitive Science Society, Inc.

VIBRATION ISOLATION SYSTEM PROBABILITY ANALYSIS

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Smirnov Vladimir Alexandrovich

2012-10-01

Full Text Available The article deals with the probability analysis for a vibration isolation system of high-precision equipment, which is extremely sensitive to low-frequency oscillations even of submicron amplitude. The external sources of low-frequency vibrations may include the natural city background or internal low-frequency sources inside buildings (pedestrian activity, HVAC. Taking Gauss distribution into account, the author estimates the probability of the relative displacement of the isolated mass being still lower than the vibration criteria. This problem is being solved in the three dimensional space, evolved by the system parameters, including damping and natural frequency. According to this probability distribution, the chance of exceeding the vibration criteria for a vibration isolation system is evaluated. Optimal system parameters - damping and natural frequency - are being developed, thus the possibility of exceeding vibration criteria VC-E and VC-D is assumed to be less than 0.04.

EL APRENDIZAJE ORGANIZACIONAL COMO FACILITADOR DE RELACIONES SOCIALES RESPONSABLES

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Eliecer Mayorca Capataz

2014-08-01

Full Text Available La importancia que tienen las relaciones sociales y el aprendizaje en la vida del ser humano: ser social, ser de relaciones, un ser abierto que se define por las relaciones con los demás, se considera imprescindible, abordar el tema para favorecer el desarrollo integral de la personas. Ello supone que, la vida para su permanente desarrollo implica en la persona, articular un entramado de relaciones, mediante la experiencia de aprendizaje y el reconocimiento de los valores fundamentales como el respeto por la humanidad, en un todo interrelacionado, en el que, de alguna forma, remite el actuar de las personas, a su racionalidad, a su espontaneidad, a la forma como se comunica y trabaja con los otros, a la manera constante de aprender, de buscar la calidad de vida, de amar su oficio como forma de influencia positiva, y establecer relaciones socialmente responsables. Para ello, se estableció como objetivo: realizar un análisis conceptual del aprendizaje organizacional como facilitador de las relaciones sociales responsables en la organización. Metodológicamente, el trabajo es de carácter documental y bibliográfico, soportadas en investigaciones previas; y como reflexión se estableció que el centro para aprender y relacionarse es el hombre.

EL CONFLICTO COMO CONSTRUCTOR DE CIUDAD

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Twiggy Ortegón

2012-04-01

Full Text Available El planteamiento central de este articulo, es el de sugerir una análisis en torno a algunas de las condiciones o mecanismo necesarios para que el conflicto opere como un potenciador de la diferencia y creador de alternativas para la convivencia Se realiza una distinción del concepto, un análisis de contenidos interaccionales en dinámicas de conflicto y su relación con el contexto urbano de Bogotá, enfocándose en ámbitos escolares. En ciudades como Bogotá, las discusiones y acciones que diferentes estamentos han emprendido frente a la manera de concebir y gestionar el conflicto, desembocan en la creación de diferentes organismos como los centros de conciliación, la aplicación de fórmulas y técnicas para la solución de conflictos, el desarrollo de propuestas desde entes administrativos a nivel distrital y las nuevas disposiciones que plantea la Ley 115 sobre Gobierno Escolar y manuales de convivencia.

The Virtue of Knowing-How = A virtude do saber-como

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Santos, Felipe Rocha Lima

2015-01-01

Full Text Available Intelectualistas sobre o conhecimento-como afirmam que o conhecimento-como é um tipo de conhecimento proposicional. Antiintelectualistas procuram demonstrar que existem casos em que o agente possui conhecimento-como, mas não possuem conhecimento proposicional. Este artigo se concentra nos recentes argumentos antiintelectualistas propostos por Carter e Pritchard. Procuro mostrar que os argumentos de Carter e Pritchard não são bem sucedidos e que, aplicando a epistemologia das virtudes ao debate, pode-se concluir que o conhecimento-como compartilha as mesmas propriedades epistêmicas que o conhecimento proposicional. Se isso é o caso, então é possível afirmar que o conhecimento-como é um tipo de conhecimento proposicional, deixando a salvo novamente o intelectualismo

Robots como ferramenta pedagógica nos primeiros anos a aprendizagem como participação

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SÓNIA MATILDE PINTO CORREIA MARTINS

2015-01-01

Full Text Available El presente artículo describe y analiza un proyecto realizado con dos grados del 1er ciclo de enseñanza básica en Portugal (2doy 3er grado que trabajaron en conjunto con robots, tomando el aprendizaje como un fenómeno intrín-secamente relacionado a la participación en comunidades de práctica (Lave, 1996; Lave; Wenger, 1991. Se pretende caracterizar a los participantes, a la metodología de trabajo implementada, describirlos artefactos utilizados (robots y escritura de una historia y analizar la relación de los participantes con los robots, así como los patrones de participación que se relevaron con este tipo de trabajo. Se busca enfatizar e las contribuciones derivadas de la participación en ambientes sociales digitales para el aprendizaje de los alumnos, como la participación y la negociación conjunta de significados, la importancia de que los robots y la historia hayan sido “construidos” por los alumnos y la existencia de un repertorio compartido y un emprendi-miento conjunto.

Optimizing Probability of Detection Point Estimate Demonstration

Science.gov (United States)

Koshti, Ajay M.

2017-01-01

Probability of detection (POD) analysis is used in assessing reliably detectable flaw size in nondestructive evaluation (NDE). MIL-HDBK-18231and associated mh18232POD software gives most common methods of POD analysis. Real flaws such as cracks and crack-like flaws are desired to be detected using these NDE methods. A reliably detectable crack size is required for safe life analysis of fracture critical parts. The paper provides discussion on optimizing probability of detection (POD) demonstration experiments using Point Estimate Method. POD Point estimate method is used by NASA for qualifying special NDE procedures. The point estimate method uses binomial distribution for probability density. Normally, a set of 29 flaws of same size within some tolerance are used in the demonstration. The optimization is performed to provide acceptable value for probability of passing demonstration (PPD) and achieving acceptable value for probability of false (POF) calls while keeping the flaw sizes in the set as small as possible.

Tragédias nas escolas americanas: como entendê-las? Como impedir que voltem a acontecer?

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Eva Paulino Bueno

2011-05-01

Full Text Available

Este artigo dá uma visão histórica do direito de portar armas nos Estados Unidos, e como a existência e facilidade de obtenção de armas têm causado inúmeras tragédias em escolas. Fala também das diferentes maneiras que as pessoas reagem às tragédias e como impedir que ocorram.

Some open problems in noncommutative probability

International Nuclear Information System (INIS)

Kruszynski, P.

1981-01-01

A generalization of probability measures to non-Boolean structures is discussed. The starting point of the theory is the Gleason theorem about the form of measures on closed subspaces of a Hilbert space. The problems are formulated in terms of probability on lattices of projections in arbitrary von Neumann algebras. (Auth.)

Counterexamples in probability

CERN Document Server

Stoyanov, Jordan M

2013-01-01

While most mathematical examples illustrate the truth of a statement, counterexamples demonstrate a statement's falsity. Enjoyable topics of study, counterexamples are valuable tools for teaching and learning. The definitive book on the subject in regards to probability, this third edition features the author's revisions and corrections plus a substantial new appendix.

Rates and reasons for early change of first HAART in HIV-1-infected patients in 7 sites throughout the Caribbean and Latin America.

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Carina Cesar

Full Text Available BACKGROUND: HAART rollout in Latin America and the Caribbean has increased from approximately 210,000 in 2003 to 390,000 patients in 2007, covering 62% (51%-70% of eligible patients, with considerable variation among countries. No multi-cohort study has examined rates of and reasons for change of initial HAART in this region. METHODOLOGY: Antiretroviral-naïve patients >or= 18 years who started HAART between 1996 and 2007 and had at least one follow-up visit from sites in Argentina, Brazil, Chile, Haiti, Honduras, Mexico and Peru were included. Time from HAART initiation to change (stopping or switching any antiretrovirals was estimated using Kaplan-Meier techniques. Cox proportional hazards modeled the associations between change and demographics, initial regimen, baseline CD4 count, and clinical stage. PRINCIPAL FINDINGS: Of 5026 HIV-infected patients, 35% were female, median age at HAART initiation was 37 years (interquartile range [IQR], 31-44, and median CD4 count was 105 cells/uL (IQR, 38-200. Estimated probabilities of changing within 3 months and one year of HAART initiation were 16% (95% confidence interval (CI 15-17% and 28% (95% CI 27-29%, respectively. Efavirenz-based regimens and no clinical AIDS at HAART initiation were associated with lower risk of change (hazard ratio (HR = 1.7 (95% CI 1.1-2.6 and 2.1 (95% CI 1.7-2.5 comparing neverapine-based regimens and other regimens to efavirenz, respectively; HR = 1.3 (95% CI 1.1-1.5 for clinical AIDS at HAART initiation. The primary reason for change among HAART initiators were adverse events (14%, death (5.7% and failure (1.3% with specific toxicities varying among sites. After change, most patients remained in first line regimens. CONCLUSIONS: Adverse events were the leading cause for changing initial HAART. Predictors for change due to any reason were AIDS at baseline and the use of a non-efavirenz containing regimen. Differences between participant sites were observed and require

Rates and Reasons for Early Change of First HAART in HIV-1-Infected Patients in 7 Sites throughout the Caribbean and Latin America

Science.gov (United States)

Cesar, Carina; Shepherd, Bryan E.; Krolewiecki, Alejandro J.; Fink, Valeria I.; Schechter, Mauro; Tuboi, Suely H.; Wolff, Marcelo; Pape, Jean W.; Leger, Paul; Padgett, Denis; Madero, Juan Sierra; Gotuzzo, Eduardo; Sued, Omar; McGowan, Catherine C.; Masys, Daniel R.; Cahn, Pedro E.

2010-01-01

Background HAART rollout in Latin America and the Caribbean has increased from approximately 210,000 in 2003 to 390,000 patients in 2007, covering 62% (51%–70%) of eligible patients, with considerable variation among countries. No multi-cohort study has examined rates of and reasons for change of initial HAART in this region. Methodology Antiretroviral-naïve patients > = 18 years who started HAART between 1996 and 2007 and had at least one follow-up visit from sites in Argentina, Brazil, Chile, Haiti, Honduras, Mexico and Peru were included. Time from HAART initiation to change (stopping or switching any antiretrovirals) was estimated using Kaplan-Meier techniques. Cox proportional hazards modeled the associations between change and demographics, initial regimen, baseline CD4 count, and clinical stage. Principal Findings Of 5026 HIV-infected patients, 35% were female, median age at HAART initiation was 37 years (interquartile range [IQR], 31–44), and median CD4 count was 105 cells/uL (IQR, 38–200). Estimated probabilities of changing within 3 months and one year of HAART initiation were 16% (95% confidence interval (CI) 15–17%) and 28% (95% CI 27–29%), respectively. Efavirenz-based regimens and no clinical AIDS at HAART initiation were associated with lower risk of change (hazard ratio (HR) = 1.7 (95% CI 1.1–2.6) and 2.1 (95% CI 1.7–2.5) comparing neverapine-based regimens and other regimens to efavirenz, respectively; HR = 1.3 (95% CI 1.1–1.5) for clinical AIDS at HAART initiation). The primary reason for change among HAART initiators were adverse events (14%), death (5.7%) and failure (1.3%) with specific toxicities varying among sites. After change, most patients remained in first line regimens. Conclusions Adverse events were the leading cause for changing initial HAART. Predictors for change due to any reason were AIDS at baseline and the use of a non-efavirenz containing regimen. Differences between participant sites were observed

La Realidad Aumentada como complemento motivacional

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Gazcón, Nicolás Fernando

2016-06-01

Full Text Available El acelerado avance de la tecnología permite que las tecnologías emergentes sean accesibles por todos los usuarios. Ejemplos de estas tecnologías son la Realidad Aumentada y la Reconstrucción 3D, que gracias a dispositivos como tabletas o teléfonos inteligentes, pueden utilizarse de manera ubicua. Éstas tienen un enorme potencial en el campo de la educación, ya sea como recurso para entender conceptos complejos, como para motivar el aprendizaje de nuevos contenidos. El desafío de estas tecnologías es integrarlas para que sean accesibles y fáciles de utilizar por los docentes y los alumnos. En este trabajo presentamos una metodología para motivar el aprendizaje tanto en tareas de campo, mediante el uso de la Reconstrucción 3D, como en el ámbito escolar mediante libros aumentados. Por medio de un caso de estudio introducimos la Reconstrucción 3D de elementos fósiles de un sitio paleontológico bonaerense, para luego incorporar estos contenidos generados en un libro aumentado. A partir de la digitalización de huellas y fósiles de sitios paleontológicos, se obtuvieron modelos 3D que se integraron en un ambiente de aprendizaje inmersivo en el aula mediante los libros aumentados. Presentamos las opiniones de docentes de distintas disciplinas, que resaltan las posibilidades de esta metodología para su inclusión en el ámbito educacional regional.

Los ancianos como actores sociales

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Mª PIA ARENYS

1996-01-01

Full Text Available En este artículo se recogen las discusiones de grupo que se realizaron durante cuatro meses en Barcelona como preparación del "II congreso de la gent gran" (II congreso de ancianos de esta ciudad, en noviembre de 1993. las discusiones se llevaron a cabo en las sedes de cada distrito, previa presentación de la ponencia por parte de un técnico. los componentes de los grupos son personas mayores sensibilizadas y comprometidas que forman parte del consejo de bienestar social del ayuntamiento de Barcelona. la metodología utilizada es cualitativa para el análisis del discurso, que se ha estructurado en los siguientes puntos: bajo el epígrafe "los ancianos como ciudadanos de derechos y obligaciones" se recogen los temas de valoración de la vejez, la familia, la jubilación, las implicaciones de los ancianos como ciudadanos de derechos y deberes y las funciones sociales de los ancianos.-- sobre estos temas, los mayores expresaron sus opiniones, que se vertieron, resumidamente, en la redacción final de la ponencia. aquí se recogen y se han analizado los materiales que ofrecen una versión de primera mano sobre lo que opinan los ancianos respecto al tema de "la valoración de la vejez".

On the shake-off probability for atomic systems

Energy Technology Data Exchange (ETDEWEB)

Santos, A.C.F., E-mail: toniufrj@gmail.com [Instituto de Física, Universidade Federal do Rio de Janeiro, P.O. Box 68528, 21941-972 Rio de Janeiro, RJ (Brazil); Almeida, D.P. [Departamento de Física, Universidade Federal de Santa Catarina, 88040-900 Florianópolis (Brazil)

2016-07-15

Highlights: • The scope is to find the relationship among SO probabilities, Z and electron density. • A scaling law is suggested, allowing us to find the SO probabilities for atoms. • SO probabilities have been scaled as a function of target Z and polarizability. - Abstract: The main scope in this work has been upon the relationship between shake-off probabilities, target atomic number and electron density. By comparing the saturation values of measured double-to-single photoionization ratios from the literature, a simple scaling law has been found, which allows us to predict the shake-off probabilities for several elements up to Z = 54 within a factor 2. The electron shake-off probabilities accompanying valence shell photoionization have been scaled as a function of the target atomic number, Z, and polarizability, α. This behavior is in qualitative agreement with the experimental results.

Quests em World Of Warcraft como estrutura narrativa seriada

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Jônatas Kerr de Oliveira

2010-10-01

Full Text Available Assumindo que as quests em World of Warcraft funcionam como uma estrutura narrativa dentro do jogo, busca-se verificar se esta estrutura apresenta características que possam caracterizá-la como uma narrativa seriada. Para tal, é feita uma análise das principais características da narrativa seriada televisiva, assim como da estrutura de quests, para verificar a viabilidade de tal aproximação. Sendo a estrutura narrativa de quests em MMORPGs uma estrutura narrativa seriada, abre-se um grande leque de possibilidades, tanto para as análises teóricas dos videogames, utilizando o ferramental adaptado, como para os game designers utilizarem este referencial para acrescer detalhes aos mundos ficcionais criados.

Simulations of Probabilities for Quantum Computing

Science.gov (United States)

Zak, M.

1996-01-01

It has been demonstrated that classical probabilities, and in particular, probabilistic Turing machine, can be simulated by combining chaos and non-LIpschitz dynamics, without utilization of any man-made devices (such as random number generators). Self-organizing properties of systems coupling simulated and calculated probabilities and their link to quantum computations are discussed.

Probability theory a foundational course

CERN Document Server

Pakshirajan, R P

2013-01-01

This book shares the dictum of J. L. Doob in treating Probability Theory as a branch of Measure Theory and establishes this relation early. Probability measures in product spaces are introduced right at the start by way of laying the ground work to later claim the existence of stochastic processes with prescribed finite dimensional distributions. Other topics analysed in the book include supports of probability measures, zero-one laws in product measure spaces, Erdos-Kac invariance principle, functional central limit theorem and functional law of the iterated logarithm for independent variables, Skorohod embedding, and the use of analytic functions of a complex variable in the study of geometric ergodicity in Markov chains. This book is offered as a text book for students pursuing graduate programs in Mathematics and or Statistics. The book aims to help the teacher present the theory with ease, and to help the student sustain his interest and joy in learning the subject.

O SERTÃO COMO FORMA DE PENSAMENTO

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Willi Bolle

1998-10-01

Full Text Available Focalizando um micromodelo do sertão, o "Liso do Sussuarão", este ensaio es tuda a construção da paisagem em Grande sertão: veredas como componente de um retrato do Brasil. Partindo do confronto entregeografia inventada e geografia rea l, examina-se a tese rosiana do sertãocomo um "pensamento" que "se forma mais forte do que o poder do lugar", comparando essa tese com o paradigma dos viajantes naturalistas, o determinismo positivista de Euclides da Cunha e a nova historiografia. Como traço estilístico dominante é detectado um modo de escreverque S€ pode chamar de "poética da dissolução", pela qual o romance de Rosa se configura como um poderoso dissolvente de outros tipos de discursos sobre o Brasil.

La subjetividad como superación del reproductivismo

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Gabriela Yamila Gómez

2013-01-01

Full Text Available El artículo tiene como objetivo recuperar la esfera de lo subjetivo como eje de la teoría y de la investigación social. Se proponen dos argumentos principales: a el abordaje de la subjetividad no equivale a subjetivismo; y b tampoco equivale a una mirada microsociológica que no dé cuenta de los procesos sociales generales. Partiendo de estas dos premisas, el estudio del mundo de la vida experimentado y realizado por los sujetos permitirá superar el reproductivismo, comprendiendo la relación entre las condiciones objetivas y subjetivas, así como la posibilidad y existencia del cambio social.

Epistemology and Probability

CERN Document Server

Plotnitsky, Arkady

2010-01-01

Offers an exploration of the relationships between epistemology and probability in the work of Niels Bohr, Werner Heisenberg, and Erwin Schrodinger; in quantum mechanics; and in modern physics. This book considers the implications of these relationships and of quantum theory for our understanding of the nature of thinking and knowledge in general

Pesquisa como instrumento da prática

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Maura Maria Guimarães de Almeida

1995-06-01

Full Text Available O trabalho aborda a utilização da pesquisa como instrumento da prática profissional da enfermaria na área de assistência, administração e ensino. Situa a ciência como processo. Ressalta a responsabilidade da enfermeira na produção da conhecimento científico. Destaca os fatores que dificultam e facilitam a pesquisa, além dos aspectos éticos envolvidos.

Ensayos argumentativos en inglés como lengua extranjera y su escritura como una práctica social situada: revisión de conceptos

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Pedro Antonio Chala

2013-01-01

Full Text Available Este artículo presenta una discusión sobre las tendencias teóricas que ven la escritura de ensayos argumentativos en inglés lengua extranjera como práctica social situada. Los conceptos que se exploran en este documento constituyen la base de una propuesta de investigación que aborda la escritura argumentativa desde una perspectiva innovadora, social, situada, y basada en la enseñanza de géneros que se puede ver como una alternativa para fomentar la escritura de ensayos en inglés lengua extranjera como una práctica social situada que trascienda los límites del salón de clase. La discusión de los conceptos se visualiza primero desde la teoría de aprendizaje de una segunda lengua y los dominios de la lingüística aplicada que fundamentan la propuesta. Luego se presentan, se exploran y se explican los conceptos centrales; éstos incluyen, primero, la escritura como práctica social situada, segundo, la escritura de ensayos argumentativos como un proceso dinámico de creación, y tercero, el género como acción social situada. Finalmente, el artículo presenta una reflexión sobre cómo estos conceptos se pueden entender e interrelacionar para que la escritura de ensayos argumentativos sea abordada como una práctica de alfabetización que contribuya a la formación de estudiantes de inglés lengua extranjera como escritores reflexivos, críticos y sociales.

Analytic Neutrino Oscillation Probabilities in Matter: Revisited

Energy Technology Data Exchange (ETDEWEB)

Parke, Stephen J. [Fermilab; Denton, Peter B. [Copenhagen U.; Minakata, Hisakazu [Madrid, IFT

2018-01-02

We summarize our recent paper on neutrino oscillation probabilities in matter, explaining the importance, relevance and need for simple, highly accurate approximations to the neutrino oscillation probabilities in matter.

The estimation of small probabilities and risk assessment

International Nuclear Information System (INIS)

Kalbfleisch, J.D.; Lawless, J.F.; MacKay, R.J.

1982-01-01

The primary contribution of statistics to risk assessment is in the estimation of probabilities. Frequently the probabilities in question are small, and their estimation is particularly difficult. The authors consider three examples illustrating some problems inherent in the estimation of small probabilities

Probability Weighting and Loss Aversion in Futures Hedging

NARCIS (Netherlands)

Mattos, F.; Garcia, P.; Pennings, J.M.E.

2008-01-01

We analyze how the introduction of probability weighting and loss aversion in a futures hedging model affects decision making. Analytical findings indicate that probability weighting alone always affects optimal hedge ratios, while loss and risk aversion only have an impact when probability

Probability theory and applications

CERN Document Server

Hsu, Elton P

1999-01-01

This volume, with contributions by leading experts in the field, is a collection of lecture notes of the six minicourses given at the IAS/Park City Summer Mathematics Institute. It introduces advanced graduates and researchers in probability theory to several of the currently active research areas in the field. Each course is self-contained with references and contains basic materials and recent results. Topics include interacting particle systems, percolation theory, analysis on path and loop spaces, and mathematical finance. The volume gives a balanced overview of the current status of probability theory. An extensive bibliography for further study and research is included. This unique collection presents several important areas of current research and a valuable survey reflecting the diversity of the field.

Waste Package Misload Probability

International Nuclear Information System (INIS)

Knudsen, J.K.

2001-01-01

The objective of this calculation is to calculate the probability of occurrence for fuel assembly (FA) misloads (i.e., Fa placed in the wrong location) and FA damage during FA movements. The scope of this calculation is provided by the information obtained from the Framatome ANP 2001a report. The first step in this calculation is to categorize each fuel-handling events that occurred at nuclear power plants. The different categories are based on FAs being damaged or misloaded. The next step is to determine the total number of FAs involved in the event. Using the information, a probability of occurrence will be calculated for FA misload and FA damage events. This calculation is an expansion of preliminary work performed by Framatome ANP 2001a

Concept of probability in statistical physics

CERN Document Server

Guttmann, Y M

1999-01-01

Foundational issues in statistical mechanics and the more general question of how probability is to be understood in the context of physical theories are both areas that have been neglected by philosophers of physics. This book fills an important gap in the literature by providing a most systematic study of how to interpret probabilistic assertions in the context of statistical mechanics. The book explores both subjectivist and objectivist accounts of probability, and takes full measure of work in the foundations of probability theory, in statistical mechanics, and in mathematical theory. It will be of particular interest to philosophers of science, physicists and mathematicians interested in foundational issues, and also to historians of science.

Maximum Entropy and Probability Kinematics Constrained by Conditionals

Directory of Open Access Journals (Sweden)

Stefan Lukits

2015-03-01

Full Text Available Two open questions of inductive reasoning are solved: (1 does the principle of maximum entropy (PME give a solution to the obverse Majerník problem; and (2 isWagner correct when he claims that Jeffrey’s updating principle (JUP contradicts PME? Majerník shows that PME provides unique and plausible marginal probabilities, given conditional probabilities. The obverse problem posed here is whether PME also provides such conditional probabilities, given certain marginal probabilities. The theorem developed to solve the obverse Majerník problem demonstrates that in the special case introduced by Wagner PME does not contradict JUP, but elegantly generalizes it and offers a more integrated approach to probability updating.

Determining probabilities of geologic events and processes

International Nuclear Information System (INIS)

Hunter, R.L.; Mann, C.J.; Cranwell, R.M.

1985-01-01

The Environmental Protection Agency has recently published a probabilistic standard for releases of high-level radioactive waste from a mined geologic repository. The standard sets limits for contaminant releases with more than one chance in 100 of occurring within 10,000 years, and less strict limits for releases of lower probability. The standard offers no methods for determining probabilities of geologic events and processes, and no consensus exists in the waste-management community on how to do this. Sandia National Laboratories is developing a general method for determining probabilities of a given set of geologic events and processes. In addition, we will develop a repeatable method for dealing with events and processes whose probability cannot be determined. 22 refs., 4 figs

Probability and statistics with integrated software routines

CERN Document Server

Deep, Ronald

2005-01-01

Probability & Statistics with Integrated Software Routines is a calculus-based treatment of probability concurrent with and integrated with statistics through interactive, tailored software applications designed to enhance the phenomena of probability and statistics. The software programs make the book unique.The book comes with a CD containing the interactive software leading to the Statistical Genie. The student can issue commands repeatedly while making parameter changes to observe the effects. Computer programming is an excellent skill for problem solvers, involving design, prototyping, data gathering, testing, redesign, validating, etc, all wrapped up in the scientific method.See also: CD to accompany Probability and Stats with Integrated Software Routines (0123694698)* Incorporates more than 1,000 engaging problems with answers* Includes more than 300 solved examples* Uses varied problem solving methods

La Seguridad ciudadana como función del Estado

OpenAIRE

Ridaura Martínez, María Josefa

2014-01-01

Este trabajo se centra en uno de los temas medulares de la organización del Estado como es la garantía de la seguridad, y tiene como objeto reivindicar, al calor la reciente sacudida legislativa en materia, la función de la Seguridad ciudadana como una función pública a desarrollar por las Fuerzas y Cuerpos de Seguridad; en tanto que exigencia constitucional, presupuesto de la salvaguarda de los derechos fundamentales y de las libertades públicas.

Random phenomena fundamentals of probability and statistics for engineers

CERN Document Server

Ogunnaike, Babatunde A

2009-01-01

PreludeApproach PhilosophyFour Basic PrinciplesI FoundationsTwo Motivating ExamplesYield Improvement in a Chemical ProcessQuality Assurance in a Glass Sheet Manufacturing ProcessOutline of a Systematic ApproachRandom Phenomena, Variability, and UncertaintyTwo Extreme Idealizations of Natural PhenomenaRandom Mass PhenomenaIntroducing ProbabilityThe Probabilistic FrameworkII ProbabilityFundamentals of Probability TheoryBuilding BlocksOperationsProbabilityConditional ProbabilityIndependenceRandom Variables and DistributionsDistributionsMathematical ExpectationCharacterizing DistributionsSpecial Derived Probability FunctionsMultidimensional Random VariablesDistributions of Several Random VariablesDistributional Characteristics of Jointly Distributed Random VariablesRandom Variable TransformationsSingle Variable TransformationsBivariate TransformationsGeneral Multivariate TransformationsApplication Case Studies I: ProbabilityMendel and HeredityWorld War II Warship Tactical Response Under AttackIII DistributionsIde...

Examples of Neutrosophic Probability in Physics

Directory of Open Access Journals (Sweden)

Fu Yuhua

2015-01-01

Full Text Available This paper re-discusses the problems of the so-called “law of nonconservation of parity” and “accelerating expansion of the universe”, and presents the examples of determining Neutrosophic Probability of the experiment of Chien-Shiung Wu et al in 1957, and determining Neutrosophic Probability of accelerating expansion of the partial universe.

Probability elements of the mathematical theory

CERN Document Server

Heathcote, C R

2000-01-01

Designed for students studying mathematical statistics and probability after completing a course in calculus and real variables, this text deals with basic notions of probability spaces, random variables, distribution functions and generating functions, as well as joint distributions and the convergence properties of sequences of random variables. Includes worked examples and over 250 exercises with solutions.

Electrofishing capture probability of smallmouth bass in streams

Science.gov (United States)

Dauwalter, D.C.; Fisher, W.L.

2007-01-01

Abundance estimation is an integral part of understanding the ecology and advancing the management of fish populations and communities. Mark-recapture and removal methods are commonly used to estimate the abundance of stream fishes. Alternatively, abundance can be estimated by dividing the number of individuals sampled by the probability of capture. We conducted a mark-recapture study and used multiple repeated-measures logistic regression to determine the influence of fish size, sampling procedures, and stream habitat variables on the cumulative capture probability for smallmouth bass Micropterus dolomieu in two eastern Oklahoma streams. The predicted capture probability was used to adjust the number of individuals sampled to obtain abundance estimates. The observed capture probabilities were higher for larger fish and decreased with successive electrofishing passes for larger fish only. Model selection suggested that the number of electrofishing passes, fish length, and mean thalweg depth affected capture probabilities the most; there was little evidence for any effect of electrofishing power density and woody debris density on capture probability. Leave-one-out cross validation showed that the cumulative capture probability model predicts smallmouth abundance accurately. ?? Copyright by the American Fisheries Society 2007.

On the Hitting Probability of Max-Stable Processes

OpenAIRE

Hofmann, Martin

2012-01-01

The probability that a max-stable process {\\eta} in C[0, 1] with identical marginal distribution function F hits x \\in R with 0 < F (x) < 1 is the hitting probability of x. We show that the hitting probability is always positive, unless the components of {\\eta} are completely dependent. Moreover, we consider the event that the paths of standard MSP hit some x \\in R twice and we give a sufficient condition for a positive probability of this event.

Risk estimation using probability machines

Science.gov (United States)

2014-01-01

Background Logistic regression has been the de facto, and often the only, model used in the description and analysis of relationships between a binary outcome and observed features. It is widely used to obtain the conditional probabilities of the outcome given predictors, as well as predictor effect size estimates using conditional odds ratios. Results We show how statistical learning machines for binary outcomes, provably consistent for the nonparametric regression problem, can be used to provide both consistent conditional probability estimation and conditional effect size estimates. Effect size estimates from learning machines leverage our understanding of counterfactual arguments central to the interpretation of such estimates. We show that, if the data generating model is logistic, we can recover accurate probability predictions and effect size estimates with nearly the same efficiency as a correct logistic model, both for main effects and interactions. We also propose a method using learning machines to scan for possible interaction effects quickly and efficiently. Simulations using random forest probability machines are presented. Conclusions The models we propose make no assumptions about the data structure, and capture the patterns in the data by just specifying the predictors involved and not any particular model structure. So they do not run the same risks of model mis-specification and the resultant estimation biases as a logistic model. This methodology, which we call a “risk machine”, will share properties from the statistical machine that it is derived from. PMID:24581306

Fixation Probability in a Haploid-Diploid Population.

Science.gov (United States)

Bessho, Kazuhiro; Otto, Sarah P

2017-01-01

Classical population genetic theory generally assumes either a fully haploid or fully diploid life cycle. However, many organisms exhibit more complex life cycles, with both free-living haploid and diploid stages. Here we ask what the probability of fixation is for selected alleles in organisms with haploid-diploid life cycles. We develop a genetic model that considers the population dynamics using both the Moran model and Wright-Fisher model. Applying a branching process approximation, we obtain an accurate fixation probability assuming that the population is large and the net effect of the mutation is beneficial. We also find the diffusion approximation for the fixation probability, which is accurate even in small populations and for deleterious alleles, as long as selection is weak. These fixation probabilities from branching process and diffusion approximations are similar when selection is weak for beneficial mutations that are not fully recessive. In many cases, particularly when one phase predominates, the fixation probability differs substantially for haploid-diploid organisms compared to either fully haploid or diploid species. Copyright © 2017 by the Genetics Society of America.

Causal inference, probability theory, and graphical insights.

Science.gov (United States)

Baker, Stuart G

2013-11-10

Causal inference from observational studies is a fundamental topic in biostatistics. The causal graph literature typically views probability theory as insufficient to express causal concepts in observational studies. In contrast, the view here is that probability theory is a desirable and sufficient basis for many topics in causal inference for the following two reasons. First, probability theory is generally more flexible than causal graphs: Besides explaining such causal graph topics as M-bias (adjusting for a collider) and bias amplification and attenuation (when adjusting for instrumental variable), probability theory is also the foundation of the paired availability design for historical controls, which does not fit into a causal graph framework. Second, probability theory is the basis for insightful graphical displays including the BK-Plot for understanding Simpson's paradox with a binary confounder, the BK2-Plot for understanding bias amplification and attenuation in the presence of an unobserved binary confounder, and the PAD-Plot for understanding the principal stratification component of the paired availability design. Published 2013. This article is a US Government work and is in the public domain in the USA.

Chance, determinism and the classical theory of probability.

Science.gov (United States)

Vasudevan, Anubav

2018-02-01

This paper situates the metaphysical antinomy between chance and determinism in the historical context of some of the earliest developments in the mathematical theory of probability. Since Hacking's seminal work on the subject, it has been a widely held view that the classical theorists of probability were guilty of an unwitting equivocation between a subjective, or epistemic, interpretation of probability, on the one hand, and an objective, or statistical, interpretation, on the other. While there is some truth to this account, I argue that the tension at the heart of the classical theory of probability is not best understood in terms of the duality between subjective and objective interpretations of probability. Rather, the apparent paradox of chance and determinism, when viewed through the lens of the classical theory of probability, manifests itself in a much deeper ambivalence on the part of the classical probabilists as to the rational commensurability of causal and probabilistic reasoning. Copyright © 2017 Elsevier Ltd. All rights reserved.

LA UTOPÍA FEMINISTA COMO TRANSGRESIÓN

Directory of Open Access Journals (Sweden)

Maria Luisa Femenias

2013-04-01

Full Text Available Resumen Tal como sucede –según lo enunció Kate Millet hace más de cincuenta años- respecto de las vanguardias literarias de comienzos del siglo XX, las estudiosas actuales de la literatura utópica reconocen que el esquema tradicional seguido por los escritores varones es “utópico” en todos sus aspectos, menos en la deconstrucción de los roles de sexo-género. Sobre este marco general, revisaré la noción de “utopía feminista” como transgresión al modelo canónico y, a su vez, desafío al orden social considerado “natural”. Para ello, examinaré algunos problemas vinculados a la caracterización de la literatura utópica como tal, y el frecuente abandono de sus fundamentos filosóficos.

Probability, statistics, and queueing theory

CERN Document Server

Allen, Arnold O

1990-01-01

This is a textbook on applied probability and statistics with computer science applications for students at the upper undergraduate level. It may also be used as a self study book for the practicing computer science professional. The successful first edition of this book proved extremely useful to students who need to use probability, statistics and queueing theory to solve problems in other fields, such as engineering, physics, operations research, and management science. The book has also been successfully used for courses in queueing theory for operations research students. This second edit

Probability, Statistics, and Stochastic Processes

CERN Document Server

Olofsson, Peter

2011-01-01

A mathematical and intuitive approach to probability, statistics, and stochastic processes This textbook provides a unique, balanced approach to probability, statistics, and stochastic processes. Readers gain a solid foundation in all three fields that serves as a stepping stone to more advanced investigations into each area. This text combines a rigorous, calculus-based development of theory with a more intuitive approach that appeals to readers' sense of reason and logic, an approach developed through the author's many years of classroom experience. The text begins with three chapters that d

Probability and Statistics: 5 Questions

DEFF Research Database (Denmark)

Probability and Statistics: 5 Questions is a collection of short interviews based on 5 questions presented to some of the most influential and prominent scholars in probability and statistics. We hear their views on the fields, aims, scopes, the future direction of research and how their work fits...... in these respects. Interviews with Nick Bingham, Luc Bovens, Terrence L. Fine, Haim Gaifman, Donald Gillies, James Hawthorne, Carl Hoefer, James M. Joyce, Joseph B. Kadane Isaac Levi, D.H. Mellor, Patrick Suppes, Jan von Plato, Carl Wagner, Sandy Zabell...

14 CFR 417.224 - Probability of failure analysis.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Probability of failure analysis. 417.224..., DEPARTMENT OF TRANSPORTATION LICENSING LAUNCH SAFETY Flight Safety Analysis § 417.224 Probability of failure..., must account for launch vehicle failure probability in a consistent manner. A launch vehicle failure...

Students' Understanding of Conditional Probability on Entering University

Science.gov (United States)

Reaburn, Robyn

2013-01-01

An understanding of conditional probability is essential for students of inferential statistics as it is used in Null Hypothesis Tests. Conditional probability is also used in Bayes' theorem, in the interpretation of medical screening tests and in quality control procedures. This study examines the understanding of conditional probability of…

Elements of probability and statistics an introduction to probability with De Finetti’s approach and to Bayesian statistics

CERN Document Server

Biagini, Francesca

2016-01-01

This book provides an introduction to elementary probability and to Bayesian statistics using de Finetti's subjectivist approach. One of the features of this approach is that it does not require the introduction of sample space – a non-intrinsic concept that makes the treatment of elementary probability unnecessarily complicate – but introduces as fundamental the concept of random numbers directly related to their interpretation in applications. Events become a particular case of random numbers and probability a particular case of expectation when it is applied to events. The subjective evaluation of expectation and of conditional expectation is based on an economic choice of an acceptable bet or penalty. The properties of expectation and conditional expectation are derived by applying a coherence criterion that the evaluation has to follow. The book is suitable for all introductory courses in probability and statistics for students in Mathematics, Informatics, Engineering, and Physics.

The collision probability modules of WIMS-E

International Nuclear Information System (INIS)

Roth, M.J.

1985-04-01

This report describes how flat source first flight collision probabilities are calculated and used in the WIMS-E modular program. It includes a description of the input to the modules W-FLU, W-THES, W-PIP, W-PERS and W-MERGE. Input to other collision probability modules are described in separate reports. WIMS-E is capable of calculating collision probabilities in a wide variety of geometries, some of them quite complicated. It can also use them for a variety of purposes. (author)

La naturaleza como contraseña del comportamiento moral en Lucrecio

Directory of Open Access Journals (Sweden)

Ramón Román Alcalá

2015-01-01

Full Text Available Voy a intentar probar que en Lucrecio la naturaleza actúa como elemento clave para todo su sistema. Con una lógica coherente el poeta demuestra que la naturaleza como principio de realidad está sustentando, primero la creación del cosmos como principio material, segundo, el desarrollo de la raza humana, como principio antropológico y, por último, la acción y la conducta humana como principio moral. La naturaleza es, así, una marca para la comprensión del cosmos, una clave para el conocimiento de la humanidad y una contraseña que activa el comportamiento moral.

Ouabaina como Hormona

OpenAIRE

J. Hernando Ordoñez

1996-01-01

Comentario sobre su origen endógeno y sus aplicaciones terapéuticas

Pocas drogas han sido más estudiadas que el grupo de los digitálicos, estrofantinas y ouabaina, cuyo estudio es objeto del presente trabajo.

La ouabaina empezó a ser estudiada desde el siglo pasado. La primera referencia conocida corresponde a Pelikan, 1865 (1), como veneno que empleaban para las flechas en Gabón (Africa). (.)

Los patrones de asentamiento como recurso patrimonial

Directory of Open Access Journals (Sweden)

Antonio Lista Martín

2012-12-01

Full Text Available Los patrones de asentamiento son las pautas con las que distribuyen los diferentes elementos construidos, como casas, caminos, campos, espacios públicos o fábricas, y son una expresión cultural de la sociedad que los construye. Tanto el tipo de elementos, su número como su distribución, dependen del nivel tecnológico, de la estructura social y de su bagaje cultural. Se puede decir, por tanto, que en los patrones estaría reflejado el conocimiento que la sociedad tenia del medio, así como sus anhelos, prioridades e, incluso, sus malas prácticas. La presente comunicación propone que estos patrones puedan servir de base para el planeamiento territorial actual, no sólo preservando aquello que realmente tenga valor, sino incluso recreándolos o reproduciéndolos a otras escalas siempre que puedan aportar un valor añadido al territorio. El escrito plantea una pregunta: ¿Qué se debe mantener de los patrones tradicionales y qué se puede, o incluso se debe, cambiar?, y para responderla en la primera parte se analizan someramente algunos asentamientos-tipo y en la segunda se indican pautas de actuación que han aparecido como propuestas en planes de ordenación territorial en los últimos años.

Fixation probability on clique-based graphs

Science.gov (United States)

Choi, Jeong-Ok; Yu, Unjong

2018-02-01

The fixation probability of a mutant in the evolutionary dynamics of Moran process is calculated by the Monte-Carlo method on a few families of clique-based graphs. It is shown that the complete suppression of fixation can be realized with the generalized clique-wheel graph in the limit of small wheel-clique ratio and infinite size. The family of clique-star is an amplifier, and clique-arms graph changes from amplifier to suppressor as the fitness of the mutant increases. We demonstrate that the overall structure of a graph can be more important to determine the fixation probability than the degree or the heat heterogeneity. The dependence of the fixation probability on the position of the first mutant is discussed.

Correlations and Non-Linear Probability Models

DEFF Research Database (Denmark)

Breen, Richard; Holm, Anders; Karlson, Kristian Bernt

2014-01-01

the dependent variable of the latent variable model and its predictor variables. We show how this correlation can be derived from the parameters of non-linear probability models, develop tests for the statistical significance of the derived correlation, and illustrate its usefulness in two applications. Under......Although the parameters of logit and probit and other non-linear probability models are often explained and interpreted in relation to the regression coefficients of an underlying linear latent variable model, we argue that they may also be usefully interpreted in terms of the correlations between...... certain circumstances, which we explain, the derived correlation provides a way of overcoming the problems inherent in cross-sample comparisons of the parameters of non-linear probability models....

Paradoxes in probability theory

CERN Document Server

Eckhardt, William

2013-01-01

Paradoxes provide a vehicle for exposing misinterpretations and misapplications of accepted principles. This book discusses seven paradoxes surrounding probability theory.  Some remain the focus of controversy; others have allegedly been solved, however the accepted solutions are demonstrably incorrect. Each paradox is shown to rest on one or more fallacies.  Instead of the esoteric, idiosyncratic, and untested methods that have been brought to bear on these problems, the book invokes uncontroversial probability principles, acceptable both to frequentists and subjectivists. The philosophical disputation inspired by these paradoxes is shown to be misguided and unnecessary; for instance, startling claims concerning human destiny and the nature of reality are directly related to fallacious reasoning in a betting paradox, and a problem analyzed in philosophy journals is resolved by means of a computer program.

Danzas como tradición y como disputa: la ilusión comunitaria china en el Soconusco chiapaneco

OpenAIRE

Lisbona Guillén, Miguel

2015-01-01

Referir la impronta dejada por los inmigrantes chinos que llegaron a Chiapas a finales del siglo XIX y principios del XX parece algo manido para quien conoce el estado y, muy especialmente, su región costera: el Soconusco. Sin embargo, lo obvio, por perceptible, como puede ser la existencia de una tradición gastronómica conocida como comida china, y convertida en marca de identidad en la región, no significa que la construcción de "lo chino" o de una "comunidad china" por parte de los hijos o...

Probabilities the little numbers that rule our lives

CERN Document Server

Olofsson, Peter

2014-01-01

Praise for the First Edition"If there is anything you want to know, or remind yourself, about probabilities, then look no further than this comprehensive, yet wittily written and enjoyable, compendium of how to apply probability calculations in real-world situations."- Keith Devlin, Stanford University, National Public Radio's "Math Guy" and author of The Math Gene and The Unfinished GameFrom probable improbabilities to regular irregularities, Probabilities: The Little Numbers That Rule Our Lives, Second Edition investigates the often surprising effects of risk and chance in our lives. Featur

Probability and Statistical Inference

OpenAIRE

Prosper, Harrison B.

2006-01-01

These lectures introduce key concepts in probability and statistical inference at a level suitable for graduate students in particle physics. Our goal is to paint as vivid a picture as possible of the concepts covered.

Crash probability estimation via quantifying driver hazard perception.

Science.gov (United States)

Li, Yang; Zheng, Yang; Wang, Jianqiang; Kodaka, Kenji; Li, Keqiang

2018-07-01

Crash probability estimation is an important method to predict the potential reduction of crash probability contributed by forward collision avoidance technologies (FCATs). In this study, we propose a practical approach to estimate crash probability, which combines a field operational test and numerical simulations of a typical rear-end crash model. To consider driver hazard perception characteristics, we define a novel hazard perception measure, called as driver risk response time, by considering both time-to-collision (TTC) and driver braking response to impending collision risk in a near-crash scenario. Also, we establish a driving database under mixed Chinese traffic conditions based on a CMBS (Collision Mitigation Braking Systems)-equipped vehicle. Applying the crash probability estimation in this database, we estimate the potential decrease in crash probability owing to use of CMBS. A comparison of the results with CMBS on and off shows a 13.7% reduction of crash probability in a typical rear-end near-crash scenario with a one-second delay of driver's braking response. These results indicate that CMBS is positive in collision prevention, especially in the case of inattentive drivers or ole drivers. The proposed crash probability estimation offers a practical way for evaluating the safety benefits in the design and testing of FCATs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Escape probabilities for fluorescent x-rays

International Nuclear Information System (INIS)

Dance, D.R.; Day, G.J.

1985-01-01

Computation of the energy absorption efficiency of an x-ray photon detector involves consideration of the histories of the secondary particles produced in any initial or secondary interaction which may occur within the detector. In particular, the K or higher shell fluorescent x-rays which may be emitted following a photoelectric interaction can carry away a large fraction of the energy of the incident photon, especially if this energy is just above an absorption edge. The effects of such photons cannot be ignored and a correction term, depending upon the probability that the fluorescent x-rays will escape from the detector, must be applied to the energy absorption efficiency. For detectors such as x-ray intensifying screens, it has been usual to calculate this probability by numerical integration. In this note analytic expressions are derived for the escape probability of fluorescent photons from planar detectors in terms of exponential integral functions. Rational approximations for these functions are readily available and these analytic expressions therefore facilitate the computation of photon absorption efficiencies. A table is presented which should obviate the need for calculating the escape probability for most cases of interest. (author)

Concepts of probability theory

CERN Document Server

Pfeiffer, Paul E

1979-01-01

Using the Kolmogorov model, this intermediate-level text discusses random variables, probability distributions, mathematical expectation, random processes, more. For advanced undergraduates students of science, engineering, or math. Includes problems with answers and six appendixes. 1965 edition.

Dependency models and probability of joint events

International Nuclear Information System (INIS)

Oerjasaeter, O.

1982-08-01

Probabilistic dependencies between components/systems are discussed with reference to a broad classification of potential failure mechanisms. Further, a generalized time-dependency model, based on conditional probabilities for estimation of the probability of joint events and event sequences is described. The applicability of this model is clarified/demonstrated by various examples. It is concluded that the described model of dependency is a useful tool for solving a variety of practical problems concerning the probability of joint events and event sequences where common cause and time-dependent failure mechanisms are involved. (Auth.)

Probability shapes perceptual precision: A study in orientation estimation.

Science.gov (United States)

Jabar, Syaheed B; Anderson, Britt

2015-12-01

Probability is known to affect perceptual estimations, but an understanding of mechanisms is lacking. Moving beyond binary classification tasks, we had naive participants report the orientation of briefly viewed gratings where we systematically manipulated contingent probability. Participants rapidly developed faster and more precise estimations for high-probability tilts. The shapes of their error distributions, as indexed by a kurtosis measure, also showed a distortion from Gaussian. This kurtosis metric was robust, capturing probability effects that were graded, contextual, and varying as a function of stimulus orientation. Our data can be understood as a probability-induced reduction in the variability or "shape" of estimation errors, as would be expected if probability affects the perceptual representations. As probability manipulations are an implicit component of many endogenous cuing paradigms, changes at the perceptual level could account for changes in performance that might have traditionally been ascribed to "attention." (c) 2015 APA, all rights reserved).

Model uncertainty: Probabilities for models?

International Nuclear Information System (INIS)

Winkler, R.L.

1994-01-01

Like any other type of uncertainty, model uncertainty should be treated in terms of probabilities. The question is how to do this. The most commonly-used approach has a drawback related to the interpretation of the probabilities assigned to the models. If we step back and look at the big picture, asking what the appropriate focus of the model uncertainty question should be in the context of risk and decision analysis, we see that a different probabilistic approach makes more sense, although it raise some implementation questions. Current work that is underway to address these questions looks very promising

Scoring Rules for Subjective Probability Distributions

DEFF Research Database (Denmark)

Harrison, Glenn W.; Martínez-Correa, Jimmy; Swarthout, J. Todd

The theoretical literature has a rich characterization of scoring rules for eliciting the subjective beliefs that an individual has for continuous events, but under the restrictive assumption of risk neutrality. It is well known that risk aversion can dramatically affect the incentives to correctly...... report the true subjective probability of a binary event, even under Subjective Expected Utility. To address this one can “calibrate” inferences about true subjective probabilities from elicited subjective probabilities over binary events, recognizing the incentives that risk averse agents have...... to distort reports. We characterize the comparable implications of the general case of a risk averse agent when facing a popular scoring rule over continuous events, and find that these concerns do not apply with anything like the same force. For empirically plausible levels of risk aversion, one can...

The Probability Distribution for a Biased Spinner

Science.gov (United States)

Foster, Colin

2012-01-01

This article advocates biased spinners as an engaging context for statistics students. Calculating the probability of a biased spinner landing on a particular side makes valuable connections between probability and other areas of mathematics. (Contains 2 figures and 1 table.)

Los rincones como contextos significativos de aprendizaje

OpenAIRE

Sánchez Molero, María Luisa

2016-01-01

En el presente trabajo se pretende hacer un estudio sobre los rincones de trabajo en el aula de Educación Infantil, describiéndolos como modelo de organización del espacio y como estrategia metodológica que aboga por un aprendizaje socioconstructivista. El estudio se completa con la descripción y el análisis de los rincones de un aula específica de un centro escolar, incorporando diversas propuestas de mejora fundamentadas en el previo estudio teórico

Inglês como língua franca: desenvolvimentos recentes

Directory of Open Access Journals (Sweden)

Telma Gimenez

Full Text Available Em face da atual posição do inglês como uma língua franca global, este artigo tem como principal objetivo discutir os desenvolvimentos recentes dessa área, tomando como base os trabalhos apresentados durante a 7th International Conference on English as a Lingua Franca, realizada em Atenas, Grécia, em setembro de 2014. As reflexões, aprofundadas nos tópicos i Teorizações sobre ILF; ii ILF e formação de professores; iii Desenvolvimentos futuros, trazem um olhar analítico sobre os temas discutidos no evento. Espera-se que as informações e reflexões aqui contempladas possam contribuir para o desenvolvimento de uma "curiosidade acadêmica" a respeito do paradigma ILF (inglês como língua franca e para o engajamento com suas questões e implicações.

A discussion on the origin of quantum probabilities

International Nuclear Information System (INIS)

Holik, Federico; Sáenz, Manuel; Plastino, Angel

2014-01-01

We study the origin of quantum probabilities as arising from non-Boolean propositional-operational structures. We apply the method developed by Cox to non distributive lattices and develop an alternative formulation of non-Kolmogorovian probability measures for quantum mechanics. By generalizing the method presented in previous works, we outline a general framework for the deduction of probabilities in general propositional structures represented by lattices (including the non-distributive case). -- Highlights: •Several recent works use a derivation similar to that of R.T. Cox to obtain quantum probabilities. •We apply Cox’s method to the lattice of subspaces of the Hilbert space. •We obtain a derivation of quantum probabilities which includes mixed states. •The method presented in this work is susceptible to generalization. •It includes quantum mechanics and classical mechanics as particular cases

Tuberculosis como enfermedad ocupacional Tuberculosis as occupational disease

Directory of Open Access Journals (Sweden)

Alberto Mendoza-Ticona

2012-06-01

Full Text Available Existe evidencia suficiente para declarar a la tuberculosis como enfermedad ocupacional en diversos profesionales especialmente entre los trabajadores de salud. En el Perú están normados y reglamentados los derechos laborales inherentes a la tuberculosis como enfermedad ocupacional, como la cobertura por discapacidad temporal o permanente. Sin embargo, estos derechos aún no han sido suficientemente socializados. En este trabajo se presenta información sobre el riesgo de adquirir tuberculosis en el lugar de trabajo, se revisan las evidencias para declarar a la tuberculosis como enfermedad ocupacional en trabajadores de salud y se presenta la legislación peruana vigente al respecto.There is enough evidence to declare tuberculosis as an occupational disease among healthcare workers. In Peru, there are regulations granting employment rights regarding tuberculosis as an occupational disease, such as healthcare coverage for temporary or permanent disability. However, these rights have not been sufficiently socialized. This study presents information on the risk of acquiring tuberculosis in the workplace, and a review of the evidence to declare tuberculosis as an occupational disease among health care workers, presenting the current Peruvian law related.

More efficient integrated safeguards by applying a reasonable detection probability for maintaining low presence probability of undetected nuclear proliferating activities

International Nuclear Information System (INIS)

Otsuka, Naoto

2013-01-01

Highlights: • A theoretical foundation is presented for more efficient Integrated Safeguards (IS). • Probability of undetected nuclear proliferation activities should be maintained low. • For nations under IS, the probability to start proliferation activities is very low. • The fact can decrease the detection probability of IS by dozens of percentage points. • The cost of IS per nation can be cut down by reducing inspection frequencies etc. - Abstract: A theoretical foundation is presented for implementing more efficiently the present International Atomic Energy Agency (IAEA) integrated safeguards (ISs) on the basis of fuzzy evaluation of the probability that the evaluated nation will continue peaceful activities. It is shown that by determining the presence probability of undetected nuclear proliferating activities, nations under IS can be maintained at acceptably low proliferation risk levels even if the detection probability of current IS is decreased by dozens of percentage from the present value. This makes it possible to reduce inspection frequency and the number of collected samples, allowing the IAEA to cut costs per nation. This will contribute to further promotion and application of IS to more nations by the IAEA, and more efficient utilization of IAEA resources from the viewpoint of whole IS framework

Single Trial Probability Applications: Can Subjectivity Evade Frequency Limitations?

Directory of Open Access Journals (Sweden)

David Howden

2009-10-01

Full Text Available Frequency probability theorists define an event’s probability distribution as the limit of a repeated set of trials belonging to a homogeneous collective. The subsets of this collective are events which we have deficient knowledge about on an individual level, although for the larger collective we have knowledge its aggregate behavior. Hence, probabilities can only be achieved through repeated trials of these subsets arriving at the established frequencies that define the probabilities. Crovelli (2009 argues that this is a mistaken approach, and that a subjective assessment of individual trials should be used instead. Bifurcating between the two concepts of risk and uncertainty, Crovelli first asserts that probability is the tool used to manage uncertain situations, and then attempts to rebuild a definition of probability theory with this in mind. We show that such an attempt has little to gain, and results in an indeterminate application of entrepreneurial forecasting to uncertain decisions—a process far-removed from any application of probability theory.

Predicting Cumulative Incidence Probability by Direct Binomial Regression

DEFF Research Database (Denmark)

Scheike, Thomas H.; Zhang, Mei-Jie

Binomial modelling; cumulative incidence probability; cause-specific hazards; subdistribution hazard......Binomial modelling; cumulative incidence probability; cause-specific hazards; subdistribution hazard...

Subjective Probabilities for State-Dependent Continuous Utility

NARCIS (Netherlands)

P.P. Wakker (Peter)

1987-01-01

textabstractFor the expected utility model with state dependent utilities, Karni, Schmeidler and Vind (1983) have shown how to recover uniquely the involved subjective probabilities if the preferences, contingent on a hypothetical probability distribution over the state space, are known. This they

Surprisingly rational: probability theory plus noise explains biases in judgment.

Science.gov (United States)

Costello, Fintan; Watts, Paul

2014-07-01

The systematic biases seen in people's probability judgments are typically taken as evidence that people do not use the rules of probability theory when reasoning about probability but instead use heuristics, which sometimes yield reasonable judgments and sometimes yield systematic biases. This view has had a major impact in economics, law, medicine, and other fields; indeed, the idea that people cannot reason with probabilities has become a truism. We present a simple alternative to this view, where people reason about probability according to probability theory but are subject to random variation or noise in the reasoning process. In this account the effect of noise is canceled for some probabilistic expressions. Analyzing data from 2 experiments, we find that, for these expressions, people's probability judgments are strikingly close to those required by probability theory. For other expressions, this account produces systematic deviations in probability estimates. These deviations explain 4 reliable biases in human probabilistic reasoning (conservatism, subadditivity, conjunction, and disjunction fallacies). These results suggest that people's probability judgments embody the rules of probability theory and that biases in those judgments are due to the effects of random noise. (c) 2014 APA, all rights reserved.

Eruption probabilities for the Lassen Volcanic Center and regional volcanism, northern California, and probabilities for large explosive eruptions in the Cascade Range

Science.gov (United States)

Nathenson, Manuel; Clynne, Michael A.; Muffler, L.J. Patrick

2012-01-01

Chronologies for eruptive activity of the Lassen Volcanic Center and for eruptions from the regional mafic vents in the surrounding area of the Lassen segment of the Cascade Range are here used to estimate probabilities of future eruptions. For the regional mafic volcanism, the ages of many vents are known only within broad ranges, and two models are developed that should bracket the actual eruptive ages. These chronologies are used with exponential, Weibull, and mixed-exponential probability distributions to match the data for time intervals between eruptions. For the Lassen Volcanic Center, the probability of an eruption in the next year is 1.4x10-4 for the exponential distribution and 2.3x10-4 for the mixed exponential distribution. For the regional mafic vents, the exponential distribution gives a probability of an eruption in the next year of 6.5x10-4, but the mixed exponential distribution indicates that the current probability, 12,000 years after the last event, could be significantly lower. For the exponential distribution, the highest probability is for an eruption from a regional mafic vent. Data on areas and volumes of lava flows and domes of the Lassen Volcanic Center and of eruptions from the regional mafic vents provide constraints on the probable sizes of future eruptions. Probabilities of lava-flow coverage are similar for the Lassen Volcanic Center and for regional mafic vents, whereas the probable eruptive volumes for the mafic vents are generally smaller. Data have been compiled for large explosive eruptions (>≈ 5 km3 in deposit volume) in the Cascade Range during the past 1.2 m.y. in order to estimate probabilities of eruption. For erupted volumes >≈5 km3, the rate of occurrence since 13.6 ka is much higher than for the entire period, and we use these data to calculate the annual probability of a large eruption at 4.6x10-4. For erupted volumes ≥10 km3, the rate of occurrence has been reasonably constant from 630 ka to the present, giving

Predicting binary choices from probability phrase meanings.

Science.gov (United States)

Wallsten, Thomas S; Jang, Yoonhee

2008-08-01

The issues of how individuals decide which of two events is more likely and of how they understand probability phrases both involve judging relative likelihoods. In this study, we investigated whether derived scales representing probability phrase meanings could be used within a choice model to predict independently observed binary choices. If they can, this simultaneously provides support for our model and suggests that the phrase meanings are measured meaningfully. The model assumes that, when deciding which of two events is more likely, judges take a single sample from memory regarding each event and respond accordingly. The model predicts choice probabilities by using the scaled meanings of individually selected probability phrases as proxies for confidence distributions associated with sampling from memory. Predictions are sustained for 34 of 41 participants but, nevertheless, are biased slightly low. Sequential sampling models improve the fit. The results have both theoretical and applied implications.

Derivados de pirazol bivalentes como inhibidores de ingesta

OpenAIRE

Rodríguez de Fonseca, Fernando; Jagerovic, Nadine; Fernández Fernández, Cristina; Bermúdez-Silva, Francisco Javier; Goya, Pilar

2011-01-01

Derivados de pirazol bivalentes como inhibidores de ingesta. Nuevos derivados alquílicos y cicloalquílicos disustituidos por pirazol-3-carboxamidas, así como su procedimiento de obtención. Estos compuestos presentan propiedades, entre otras, para la inducción de saciedad y control de la ingesta, modulación de la grasa corporal y regulación del metabolismo lipídico.

Transition probabilities for atoms

International Nuclear Information System (INIS)

Kim, Y.K.

1980-01-01

Current status of advanced theoretical methods for transition probabilities for atoms and ions is discussed. An experiment on the f values of the resonance transitions of the Kr and Xe isoelectronic sequences is suggested as a test for the theoretical methods

La prosodia como identificador biométrico

OpenAIRE

Farrús i Cabeceran, Mireia

2011-01-01

La biometría tiene como objetivo el reconocimiento de personas mediante uno o más identificadores biométricos como la voz, la cara o las huellas dactilares, entre otros. Gracias a la buena aceptación social y el poco intrusismo en los individuos, la voz ha sido, tradicionalmente, uno de los identificadores más utilizados en los sistemas biométricos. Estos sistemas de reconocimiento basados en la voz utilizan, habitualmente, características relacionadas con el espectro de la voz. No obstante, ...

The transition probabilities of the reciprocity model

NARCIS (Netherlands)

Snijders, T.A.B.

1999-01-01

The reciprocity model is a continuous-time Markov chain model used for modeling longitudinal network data. A new explicit expression is derived for its transition probability matrix. This expression can be checked relatively easily. Some properties of the transition probabilities are given, as well

Hamiltonian theories quantization based on a probability operator

International Nuclear Information System (INIS)

Entral'go, E.E.

1986-01-01

The quantization method with a linear reflection of classical coordinate-momentum-time functions Λ(q,p,t) at quantum operators in a space of quantum states ψ, is considered. The probability operator satisfies a system of equations representing the principles of dynamical and canonical correspondences between the classical and quantum theories. The quantization based on a probability operator leads to a quantum theory with a nonnegative joint coordinate-momentum distribution function for any state ψ. The main consequences of quantum mechanics with a probability operator are discussed in comparison with the generally accepted quantum and classical theories. It is shown that a probability operator leads to an appearance of some new notions called ''subquantum'' ones. Hence the quantum theory with a probability operator does not pretend to any complete description of physical reality in terms of classical variables and by this reason contains no problems like Einstein-Podolsky-Rosen paradox. The results of some concrete problems are given: a free particle, a harmonic oscillator, an electron in the Coulomb field. These results give hope on the possibility of an experimental verification of the quantization based on a probability operator

La ciudad como ecosistema urbano

OpenAIRE

Higueras García, Esther

2013-01-01

LA CIUDAD COMO ECOSISTEMA URBANO .- La ecología y los ecosistemas .- El ecosistema urbano, definición, alcance y oportunidad .- El metabolismo urbano .- Los síntomas de la patología urbana .- Los objetivos del nuevo ecosistema urbano .- Las aportaciones de los ecobarrios

Fitness Probability Distribution of Bit-Flip Mutation.

Science.gov (United States)

Chicano, Francisco; Sutton, Andrew M; Whitley, L Darrell; Alba, Enrique

2015-01-01

Bit-flip mutation is a common mutation operator for evolutionary algorithms applied to optimize functions over binary strings. In this paper, we develop results from the theory of landscapes and Krawtchouk polynomials to exactly compute the probability distribution of fitness values of a binary string undergoing uniform bit-flip mutation. We prove that this probability distribution can be expressed as a polynomial in p, the probability of flipping each bit. We analyze these polynomials and provide closed-form expressions for an easy linear problem (Onemax), and an NP-hard problem, MAX-SAT. We also discuss a connection of the results with runtime analysis.

Comparing linear probability model coefficients across groups

DEFF Research Database (Denmark)

Holm, Anders; Ejrnæs, Mette; Karlson, Kristian Bernt

2015-01-01

of the following three components: outcome truncation, scale parameters and distributional shape of the predictor variable. These results point to limitations in using linear probability model coefficients for group comparisons. We also provide Monte Carlo simulations and real examples to illustrate......This article offers a formal identification analysis of the problem in comparing coefficients from linear probability models between groups. We show that differences in coefficients from these models can result not only from genuine differences in effects, but also from differences in one or more...... these limitations, and we suggest a restricted approach to using linear probability model coefficients in group comparisons....

Modeling experiments using quantum and Kolmogorov probability

International Nuclear Information System (INIS)

Hess, Karl

2008-01-01

Criteria are presented that permit a straightforward partition of experiments into sets that can be modeled using both quantum probability and the classical probability framework of Kolmogorov. These new criteria concentrate on the operational aspects of the experiments and lead beyond the commonly appreciated partition by relating experiments to commuting and non-commuting quantum operators as well as non-entangled and entangled wavefunctions. In other words the space of experiments that can be understood using classical probability is larger than usually assumed. This knowledge provides advantages for areas such as nanoscience and engineering or quantum computation.

Probability calculations for three-part mineral resource assessments

Science.gov (United States)

Ellefsen, Karl J.

2017-06-27

Three-part mineral resource assessment is a methodology for predicting, in a specified geographic region, both the number of undiscovered mineral deposits and the amount of mineral resources in those deposits. These predictions are based on probability calculations that are performed with computer software that is newly implemented. Compared to the previous implementation, the new implementation includes new features for the probability calculations themselves and for checks of those calculations. The development of the new implementation lead to a new understanding of the probability calculations, namely the assumptions inherent in the probability calculations. Several assumptions strongly affect the mineral resource predictions, so it is crucial that they are checked during an assessment. The evaluation of the new implementation leads to new findings about the probability calculations,namely findings regarding the precision of the computations,the computation time, and the sensitivity of the calculation results to the input.

Los portales educativos como fuente de recursos materiales

Directory of Open Access Journals (Sweden)

Felipe Gértrudix Barrio

2012-04-01

Full Text Available Los portales educativos por sus características como “distribuidores” de información y “almacenes” de recursos, constituyen para la escuela actual un soporte ideal y eficiente de información relacionado con el mundo educativo. Por otro lado, los portales temáticos educativos, como referente específico de una materia, suponen la plataforma ideal en el que los miembros de un colectivo (profesores, maestros, educadores y familias puedan establecer un punto de encuentro para participar, reflexionar, así como cooperar en la actividad docente incentivando nuevas formas de trabajo en el aula. En este sentido presentamos un ejemplo de portal temático educativo dedicado a la educación musical: MOS.

Independent events in elementary probability theory

Science.gov (United States)

Csenki, Attila

2011-07-01

In Probability and Statistics taught to mathematicians as a first introduction or to a non-mathematical audience, joint independence of events is introduced by requiring that the multiplication rule is satisfied. The following statement is usually tacitly assumed to hold (and, at best, intuitively motivated): quote specific-use="indent"> If the n events E 1, E 2, … , E n are jointly independent then any two events A and B built in finitely many steps from two disjoint subsets of E 1, E 2, … , E n are also independent. The operations 'union', 'intersection' and 'complementation' are permitted only when forming the events A and B. quote>Here we examine this statement from the point of view of elementary probability theory. The approach described here is accessible also to users of probability theory and is believed to be novel.

Introduction to probability with statistical applications

CERN Document Server

Schay, Géza

2016-01-01

Now in its second edition, this textbook serves as an introduction to probability and statistics for non-mathematics majors who do not need the exhaustive detail and mathematical depth provided in more comprehensive treatments of the subject. The presentation covers the mathematical laws of random phenomena, including discrete and continuous random variables, expectation and variance, and common probability distributions such as the binomial, Poisson, and normal distributions. More classical examples such as Montmort's problem, the ballot problem, and Bertrand’s paradox are now included, along with applications such as the Maxwell-Boltzmann and Bose-Einstein distributions in physics. Key features in new edition: * 35 new exercises * Expanded section on the algebra of sets * Expanded chapters on probabilities to include more classical examples * New section on regression * Online instructors' manual containing solutions to all exercises

Quantum interference of probabilities and hidden variable theories

International Nuclear Information System (INIS)

Srinivas, M.D.

1984-01-01

One of the fundamental contributions of Louis de Broglie, which does not get cited often, has been his analysis of the basic difference between the calculus of the probabilities as predicted by quantum theory and the usual calculus of probabilities - the one employed by most mathematicians, in its standard axiomatised version due to Kolmogorov. This paper is basically devoted to a discussion of the 'quantum interference of probabilities', discovered by de Broglie. In particular, it is shown that it is this feature of the quantum theoretic probabilities which leads to some serious constraints on the possible 'hidden-variable formulations' of quantum mechanics, including the celebrated theorem of Bell. (Auth.)

A Challenge to Ludwig von Mises’s Theory of Probability

Directory of Open Access Journals (Sweden)

Mark R. Crovelli

2010-10-01

Full Text Available The most interesting and completely overlooked aspect of Ludwig von Mises’s theory of probability is the total absence of any explicit definition for probability in his theory. This paper examines Mises’s theory of probability in light of the fact that his theory possesses no definition for probability. It is argued, first, that Mises’s theory differs in important respects from his brother’s famous theory of probability. A defense of the subjective definition for probability is then provided, which is subsequently used to critique Ludwig von Mises’s theory. It is argued that only the subjective definition for probability comports with Mises’s other philosophical positions. Since Mises did not provide an explicit definition for probability, it is suggested that he ought to have adopted a subjective definition.

Statistical probability tables CALENDF program

International Nuclear Information System (INIS)

Ribon, P.

1989-01-01

The purpose of the probability tables is: - to obtain dense data representation - to calculate integrals by quadratures. They are mainly used in the USA for calculations by Monte Carlo and in the USSR and Europe for self-shielding calculations by the sub-group method. The moment probability tables, in addition to providing a more substantial mathematical basis and calculation methods, are adapted for condensation and mixture calculations, which are the crucial operations for reactor physics specialists. However, their extension is limited by the statistical hypothesis they imply. Efforts are being made to remove this obstacle, at the cost, it must be said, of greater complexity

Knowledge typology for imprecise probabilities.

Energy Technology Data Exchange (ETDEWEB)

Wilson, G. D. (Gregory D.); Zucker, L. J. (Lauren J.)

2002-01-01

When characterizing the reliability of a complex system there are often gaps in the data available for specific subsystems or other factors influencing total system reliability. At Los Alamos National Laboratory we employ ethnographic methods to elicit expert knowledge when traditional data is scarce. Typically, we elicit expert knowledge in probabilistic terms. This paper will explore how we might approach elicitation if methods other than probability (i.e., Dempster-Shafer, or fuzzy sets) prove more useful for quantifying certain types of expert knowledge. Specifically, we will consider if experts have different types of knowledge that may be better characterized in ways other than standard probability theory.

A note on iterated function systems with discontinuous probabilities

International Nuclear Information System (INIS)

Jaroszewska, Joanna

2013-01-01

Highlights: ► Certain iterated function system with discontinuous probabilities is discussed. ► Existence of an invariant measure via the Schauder–Tychonov theorem is established. ► Asymptotic stability of the system under examination is proved. -- Abstract: We consider an example of an iterated function system with discontinuous probabilities. We prove that it posses an invariant probability measure. We also prove that it is asymptotically stable provided probabilities are positive

Measurement uncertainty and probability

CERN Document Server

Willink, Robin

2013-01-01

A measurement result is incomplete without a statement of its 'uncertainty' or 'margin of error'. But what does this statement actually tell us? By examining the practical meaning of probability, this book discusses what is meant by a '95 percent interval of measurement uncertainty', and how such an interval can be calculated. The book argues that the concept of an unknown 'target value' is essential if probability is to be used as a tool for evaluating measurement uncertainty. It uses statistical concepts, such as a conditional confidence interval, to present 'extended' classical methods for evaluating measurement uncertainty. The use of the Monte Carlo principle for the simulation of experiments is described. Useful for researchers and graduate students, the book also discusses other philosophies relating to the evaluation of measurement uncertainty. It employs clear notation and language to avoid the confusion that exists in this controversial field of science.

Bayesian optimization for computationally extensive probability distributions.

Science.gov (United States)

Tamura, Ryo; Hukushima, Koji

2018-01-01

An efficient method for finding a better maximizer of computationally extensive probability distributions is proposed on the basis of a Bayesian optimization technique. A key idea of the proposed method is to use extreme values of acquisition functions by Gaussian processes for the next training phase, which should be located near a local maximum or a global maximum of the probability distribution. Our Bayesian optimization technique is applied to the posterior distribution in the effective physical model estimation, which is a computationally extensive probability distribution. Even when the number of sampling points on the posterior distributions is fixed to be small, the Bayesian optimization provides a better maximizer of the posterior distributions in comparison to those by the random search method, the steepest descent method, or the Monte Carlo method. Furthermore, the Bayesian optimization improves the results efficiently by combining the steepest descent method and thus it is a powerful tool to search for a better maximizer of computationally extensive probability distributions.

Characteristic length of the knotting probability revisited

International Nuclear Information System (INIS)

Uehara, Erica; Deguchi, Tetsuo

2015-01-01

We present a self-avoiding polygon (SAP) model for circular DNA in which the radius of impermeable cylindrical segments corresponds to the screening length of double-stranded DNA surrounded by counter ions. For the model we evaluate the probability for a generated SAP with N segments having a given knot K through simulation. We call it the knotting probability of a knot K with N segments for the SAP model. We show that when N is large the most significant factor in the knotting probability is given by the exponentially decaying part exp(−N/N K ), where the estimates of parameter N K are consistent with the same value for all the different knots we investigated. We thus call it the characteristic length of the knotting probability. We give formulae expressing the characteristic length as a function of the cylindrical radius r ex , i.e. the screening length of double-stranded DNA. (paper)

La mundialización del Darwinismo como proceso y como texto

Directory of Open Access Journals (Sweden)

Olga Matilde Restrepo Forero

2009-10-01

Full Text Available El fenómeno de la difusión del Darwinismo ha sido ampliamente estudiado. No solo existe una “Industria de Darwin” que se ha ocupado de investigar cómo se produjo la obra de Darwin, sino que también existe una “Industria de la Difusión del Darwinismo”, que investiga los procesos de recepción del Darwinismo en diversas partes del mundo. En el artículo se cuestiona la separación entre los estudios que examinan la producción del Origen de las especies y los que estudian su posterior difusión, considerados como procesos completamente independientes. Con base en unos pocos ejemplos, se muestra cómo Darwin fue produciendo y modificando su obra a partir de las contribuciones que fue recogiendo en diferentes partes del mundo y a partir de las respuestas que fue recibiendo a medida que su obra era comentada y discutida. Fianlmente se examina cómo al estudiar la mundialización del darwinismo surge el problema de cómo definir el fenómeno bajo estudio, si con una perspectiva normativa, que imponga un orden en la proliferación de sentidos que surge como consecuencia de la expansión, o con una perspectiva no-esencialista que más bien sitúe al darwinismo en relación con sus diferentes usos y apropiaciones locales.

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

NARCIS (Netherlands)

Brus, D.J.; Gruijter, de J.J.

2003-01-01

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

Probability mapping of contaminants

International Nuclear Information System (INIS)

Rautman, C.A.; Kaplan, P.G.; McGraw, M.A.; Istok, J.D.; Sigda, J.M.

1994-01-01

Exhaustive characterization of a contaminated site is a physical and practical impossibility. Descriptions of the nature, extent, and level of contamination, as well as decisions regarding proposed remediation activities, must be made in a state of uncertainty based upon limited physical sampling. The probability mapping approach illustrated in this paper appears to offer site operators a reasonable, quantitative methodology for many environmental remediation decisions and allows evaluation of the risk associated with those decisions. For example, output from this approach can be used in quantitative, cost-based decision models for evaluating possible site characterization and/or remediation plans, resulting in selection of the risk-adjusted, least-cost alternative. The methodology is completely general, and the techniques are applicable to a wide variety of environmental restoration projects. The probability-mapping approach is illustrated by application to a contaminated site at the former DOE Feed Materials Production Center near Fernald, Ohio. Soil geochemical data, collected as part of the Uranium-in-Soils Integrated Demonstration Project, have been used to construct a number of geostatistical simulations of potential contamination for parcels approximately the size of a selective remediation unit (the 3-m width of a bulldozer blade). Each such simulation accurately reflects the actual measured sample values, and reproduces the univariate statistics and spatial character of the extant data. Post-processing of a large number of these equally likely statistically similar images produces maps directly showing the probability of exceeding specified levels of contamination (potential clean-up or personnel-hazard thresholds)

Probability mapping of contaminants

Energy Technology Data Exchange (ETDEWEB)

Rautman, C.A.; Kaplan, P.G. [Sandia National Labs., Albuquerque, NM (United States); McGraw, M.A. [Univ. of California, Berkeley, CA (United States); Istok, J.D. [Oregon State Univ., Corvallis, OR (United States); Sigda, J.M. [New Mexico Inst. of Mining and Technology, Socorro, NM (United States)

1994-04-01

Exhaustive characterization of a contaminated site is a physical and practical impossibility. Descriptions of the nature, extent, and level of contamination, as well as decisions regarding proposed remediation activities, must be made in a state of uncertainty based upon limited physical sampling. The probability mapping approach illustrated in this paper appears to offer site operators a reasonable, quantitative methodology for many environmental remediation decisions and allows evaluation of the risk associated with those decisions. For example, output from this approach can be used in quantitative, cost-based decision models for evaluating possible site characterization and/or remediation plans, resulting in selection of the risk-adjusted, least-cost alternative. The methodology is completely general, and the techniques are applicable to a wide variety of environmental restoration projects. The probability-mapping approach is illustrated by application to a contaminated site at the former DOE Feed Materials Production Center near Fernald, Ohio. Soil geochemical data, collected as part of the Uranium-in-Soils Integrated Demonstration Project, have been used to construct a number of geostatistical simulations of potential contamination for parcels approximately the size of a selective remediation unit (the 3-m width of a bulldozer blade). Each such simulation accurately reflects the actual measured sample values, and reproduces the univariate statistics and spatial character of the extant data. Post-processing of a large number of these equally likely statistically similar images produces maps directly showing the probability of exceeding specified levels of contamination (potential clean-up or personnel-hazard thresholds).

Factors influencing reporting and harvest probabilities in North American geese

Science.gov (United States)

Zimmerman, G.S.; Moser, T.J.; Kendall, W.L.; Doherty, P.F.; White, Gary C.; Caswell, D.F.

2009-01-01

We assessed variation in reporting probabilities of standard bands among species, populations, harvest locations, and size classes of North American geese to enable estimation of unbiased harvest probabilities. We included reward (US10,20,30,50, or100) and control (0) banded geese from 16 recognized goose populations of 4 species: Canada (Branta canadensis), cackling (B. hutchinsii), Ross's (Chen rossii), and snow geese (C. caerulescens). We incorporated spatially explicit direct recoveries and live recaptures into a multinomial model to estimate reporting, harvest, and band-retention probabilities. We compared various models for estimating harvest probabilities at country (United States vs. Canada), flyway (5 administrative regions), and harvest area (i.e., flyways divided into northern and southern sections) scales. Mean reporting probability of standard bands was 0.73 (95 CI 0.690.77). Point estimates of reporting probabilities for goose populations or spatial units varied from 0.52 to 0.93, but confidence intervals for individual estimates overlapped and model selection indicated that models with species, population, or spatial effects were less parsimonious than those without these effects. Our estimates were similar to recently reported estimates for mallards (Anas platyrhynchos). We provide current harvest probability estimates for these populations using our direct measures of reporting probability, improving the accuracy of previous estimates obtained from recovery probabilities alone. Goose managers and researchers throughout North America can use our reporting probabilities to correct recovery probabilities estimated from standard banding operations for deriving spatially explicit harvest probabilities.

Probability functions in the context of signed involutive meadows

NARCIS (Netherlands)

Bergstra, J.A.; Ponse, A.

2016-01-01

The Kolmogorov axioms for probability functions are placed in the context of signed meadows. A completeness theorem is stated and proven for the resulting equational theory of probability calculus. Elementary definitions of probability theory are restated in this framework.

VOLCANIC RISK ASSESSMENT - PROBABILITY AND CONSEQUENCES

International Nuclear Information System (INIS)

G.A. Valentine; F.V. Perry; S. Dartevelle

2005-01-01

Risk is the product of the probability and consequences of an event. Both of these must be based upon sound science that integrates field data, experiments, and modeling, but must also be useful to decision makers who likely do not understand all aspects of the underlying science. We review a decision framework used in many fields such as performance assessment for hazardous and/or radioactive waste disposal sites that can serve to guide the volcanological community towards integrated risk assessment. In this framework the underlying scientific understanding of processes that affect probability and consequences drive the decision-level results, but in turn these results can drive focused research in areas that cause the greatest level of uncertainty at the decision level. We review two examples of the determination of volcanic event probability: (1) probability of a new volcano forming at the proposed Yucca Mountain radioactive waste repository, and (2) probability that a subsurface repository in Japan would be affected by the nearby formation of a new stratovolcano. We also provide examples of work on consequences of explosive eruptions, within the framework mentioned above. These include field-based studies aimed at providing data for ''closure'' of wall rock erosion terms in a conduit flow model, predictions of dynamic pressure and other variables related to damage by pyroclastic flow into underground structures, and vulnerability criteria for structures subjected to conditions of explosive eruption. Process models (e.g., multiphase flow) are important for testing the validity or relative importance of possible scenarios in a volcanic risk assessment. We show how time-dependent multiphase modeling of explosive ''eruption'' of basaltic magma into an open tunnel (drift) at the Yucca Mountain repository provides insight into proposed scenarios that include the development of secondary pathways to the Earth's surface. Addressing volcanic risk within a decision

Imprecise Probability Methods for Weapons UQ

Energy Technology Data Exchange (ETDEWEB)

Picard, Richard Roy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Vander Wiel, Scott Alan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-05-13

Building on recent work in uncertainty quanti cation, we examine the use of imprecise probability methods to better characterize expert knowledge and to improve on misleading aspects of Bayesian analysis with informative prior distributions. Quantitative approaches to incorporate uncertainties in weapons certi cation are subject to rigorous external peer review, and in this regard, certain imprecise probability methods are well established in the literature and attractive. These methods are illustrated using experimental data from LANL detonator impact testing.

Probability and statistics for computer science

CERN Document Server

Johnson, James L

2011-01-01

Comprehensive and thorough development of both probability and statistics for serious computer scientists; goal-oriented: ""to present the mathematical analysis underlying probability results"" Special emphases on simulation and discrete decision theory Mathematically-rich, but self-contained text, at a gentle pace Review of calculus and linear algebra in an appendix Mathematical interludes (in each chapter) which examine mathematical techniques in the context of probabilistic or statistical importance Numerous section exercises, summaries, historical notes, and Further Readings for reinforcem

Uncertainty relation and probability. Numerical illustration

International Nuclear Information System (INIS)

Fujikawa, Kazuo; Umetsu, Koichiro

2011-01-01

The uncertainty relation and the probability interpretation of quantum mechanics are intrinsically connected, as is evidenced by the evaluation of standard deviations. It is thus natural to ask if one can associate a very small uncertainty product of suitably sampled events with a very small probability. We have shown elsewhere that some examples of the evasion of the uncertainty relation noted in the past are in fact understood in this way. We here numerically illustrate that a very small uncertainty product is realized if one performs a suitable sampling of measured data that occur with a very small probability. We introduce a notion of cyclic measurements. It is also shown that our analysis is consistent with the Landau-Pollak-type uncertainty relation. It is suggested that the present analysis may help reconcile the contradicting views about the 'standard quantum limit' in the detection of gravitational waves. (author)

A basic course in probability theory

CERN Document Server

Bhattacharya, Rabi

2016-01-01

This text develops the necessary background in probability theory underlying diverse treatments of stochastic processes and their wide-ranging applications. In this second edition, the text has been reorganized for didactic purposes, new exercises have been added and basic theory has been expanded. General Markov dependent sequences and their convergence to equilibrium is the subject of an entirely new chapter. The introduction of conditional expectation and conditional probability very early in the text maintains the pedagogic innovation of the first edition; conditional expectation is illustrated in detail in the context of an expanded treatment of martingales, the Markov property, and the strong Markov property. Weak convergence of probabilities on metric spaces and Brownian motion are two topics to highlight. A selection of large deviation and/or concentration inequalities ranging from those of Chebyshev, Cramer–Chernoff, Bahadur–Rao, to Hoeffding have been added, with illustrative comparisons of thei...

Geometric modeling in probability and statistics

CERN Document Server

Calin, Ovidiu

2014-01-01

This book covers topics of Informational Geometry, a field which deals with the differential geometric study of the manifold probability density functions. This is a field that is increasingly attracting the interest of researchers from many different areas of science, including mathematics, statistics, geometry, computer science, signal processing, physics and neuroscience. It is the authors’ hope that the present book will be a valuable reference for researchers and graduate students in one of the aforementioned fields. This textbook is a unified presentation of differential geometry and probability theory, and constitutes a text for a course directed at graduate or advanced undergraduate students interested in applications of differential geometry in probability and statistics. The book contains over 100 proposed exercises meant to help students deepen their understanding, and it is accompanied by software that is able to provide numerical computations of several information geometric objects. The reader...

Establishment probability in newly founded populations

Directory of Open Access Journals (Sweden)

Gusset Markus

2012-06-01

Full Text Available Abstract Background Establishment success in newly founded populations relies on reaching the established phase, which is defined by characteristic fluctuations of the population’s state variables. Stochastic population models can be used to quantify the establishment probability of newly founded populations; however, so far no simple but robust method for doing so existed. To determine a critical initial number of individuals that need to be released to reach the established phase, we used a novel application of the “Wissel plot”, where –ln(1 – P0(t is plotted against time t. This plot is based on the equation P0t=1–c1e–ω1t, which relates the probability of extinction by time t, P0(t, to two constants: c1 describes the probability of a newly founded population to reach the established phase, whereas ω1 describes the population’s probability of extinction per short time interval once established. Results For illustration, we applied the method to a previously developed stochastic population model of the endangered African wild dog (Lycaon pictus. A newly founded population reaches the established phase if the intercept of the (extrapolated linear parts of the “Wissel plot” with the y-axis, which is –ln(c1, is negative. For wild dogs in our model, this is the case if a critical initial number of four packs, consisting of eight individuals each, are released. Conclusions The method we present to quantify the establishment probability of newly founded populations is generic and inferences thus are transferable to other systems across the field of conservation biology. In contrast to other methods, our approach disaggregates the components of a population’s viability by distinguishing establishment from persistence.

A verdade como um problema epistemológico

Directory of Open Access Journals (Sweden)

Geilson Fernandes de Oliveira

2016-07-01

Full Text Available O presente ensaio é fruto das discussões realizadas durante a disciplina de mestrado Epistemologia das Ciências Sociais e Humanas. Aqui, objetivamos discutir sobre a verdade como um problema epistemológico. Assim, a partir do conceitual teórico utilizado durante a disciplina, entre os quais destacamos Michel Foucault, Norbert Elias, Friedrich Nietzsche e Pierre Bourdieu, tecemos considerações sobre as concepções de verdade no pensamento social contemporâneo, bem como no que diz respeito as rupturas que favoreceram a emergência de seu estado corrente – concepção da verdade como produção social e histórica. Consonante a esta discussão, realizamos ainda uma breve discussão sobre as relações de poder e saber que favorecem a constituição da verdade.

Introducing Disjoint and Independent Events in Probability.

Science.gov (United States)

Kelly, I. W.; Zwiers, F. W.

Two central concepts in probability theory are those of independence and mutually exclusive events. This document is intended to provide suggestions to teachers that can be used to equip students with an intuitive, comprehensive understanding of these basic concepts in probability. The first section of the paper delineates mutually exclusive and…

Against All Odds: When Logic Meets Probability

NARCIS (Netherlands)

van Benthem, J.; Katoen, J.-P.; Langerak, R.; Rensink, A.

2017-01-01

This paper is a light walk along interfaces between logic and probability, triggered by a chance encounter with Ed Brinksma. It is not a research paper, or a literature survey, but a pointer to issues. I discuss both direct combinations of logic and probability and structured ways in which logic can

Prospect evaluation as a function of numeracy and probability denominator.

Science.gov (United States)

Millroth, Philip; Juslin, Peter

2015-05-01

This study examines how numeracy and probability denominator (a direct-ratio probability, a relative frequency with denominator 100, a relative frequency with denominator 10,000) affect the evaluation of prospects in an expected-value based pricing task. We expected that numeracy would affect the results due to differences in the linearity of number perception and the susceptibility to denominator neglect with different probability formats. An analysis with functional measurement verified that participants integrated value and probability into an expected value. However, a significant interaction between numeracy and probability format and subsequent analyses of the parameters of cumulative prospect theory showed that the manipulation of probability denominator changed participants' psychophysical response to probability and value. Standard methods in decision research may thus confound people's genuine risk attitude with their numerical capacities and the probability format used. Copyright © 2015 Elsevier B.V. All rights reserved.

Metaversos y educación: Second Life como plataforma educativa

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Israel V. Márquez

2011-05-01

Full Text Available Presentamos en este artículo algunas de las particularidades de los metaversos como nuevos espacios formativos. Tomando como ejemplo el caso de Second Life y a partir de la propia experiencia del autor en este metaverso, se exploran las posibilidades formativas de estas nuevas plataformas audiovisuales 3D así como algunas de sus ventajas y desventajas como plataforma educativa. El estudio de las dinámicas complejas entre avatares y entre el usuario y el propio metaverso nos abren nuevas vías de investigación para el estudio de la educación en el siglo XXI que deben ser exploradas y examinadas por la comunidad educativa y académica por su importancia actual y sus posibles alternativas futuras.   

Como pieza de un rompecabezas: la construcción del paisaje como objeto jurídico

Directory of Open Access Journals (Sweden)

Norma Elizabeth Levrand

2017-01-01

Full Text Available La regulación jurídica del paisaje es relativamente nueva. Concebido a partir de la interrelación entre el hombre y la naturaleza, el derecho lo ha asimilado, en ciertos momentos, a un objeto estático, esencialmente natural. En otro periodo ha aprehendido su dinámica, regulándolo como un objeto híbrido. El paisaje está constituido por un conjunto de bienes y valores que trascienden lo puramente cultural o natural, y se conjugan en la confluencia de ambos elementos. Esta hibridez conlleva dificultades tanto en el punto previo a su regulación, es decir, en la concepción jurídica del paisaje, como al momento de su gobernanza. En este trabajo pretendemos desentrañar la construcción del paisaje como un particular objeto de regulación dentro del campo legal argentino. Para ello, realizaremos una sucinta historiografía de la regulación del paisaje para profundizar en las dos normas de mayor relevancia a nivel internacional (la Convención para la Protección del Patrimonio Mundial, Cultural y Natural de Unesco y el Convenio Europeo del Paisaje aprobado por el Consejo de Europa, a fin de analizar la construcción de este particular objeto y los dispositivos jurídicos para su Gobierno. Culminaremos con una reflexión acerca del proceso de construcción de esta pieza del rompecabezas legal.

On probability-possibility transformations

Science.gov (United States)

Klir, George J.; Parviz, Behzad

1992-01-01

Several probability-possibility transformations are compared in terms of the closeness of preserving second-order properties. The comparison is based on experimental results obtained by computer simulation. Two second-order properties are involved in this study: noninteraction of two distributions and projections of a joint distribution.

MEMORIA VISUAL COMO PARTE DEL PROCESO LECTOR

OpenAIRE

Gamero-Muñiz, Antonia

2013-01-01

Este trabajo tiene como objetivo indagar la relación entre los movimientos sacádicos, velocidad y comprensión lectora y la memoria visual en alumnos de 2ºESO, con el propósito de contribuir a la labor docente en los apoyos del aprendizaje de una correcta lectura y tomando como fundamentación teórica la importancia de la memoria visual en el proceso lector. Se ha seleccionado una muestra de 24 niños y 21 niñas con edades comprendidas entre 13 y 15 años. Se evaluaron los movimientos sacádico...

PARP-1 como regulador del ciclo celular

OpenAIRE

Iglesias Vázquez, Pablo

2015-01-01

En el presente estudio hemos querido investigar las implicaciones biológicas de la interacción PARP-1/E2F-1 en escenarios en los que el factor de transcripción E2F-1 resulta de gran importancia como son el desarrollo embrionario y la oncogénesis. En este respecto, hemos demostrado que tanto PJ34, inhibidor de la actividad enzimática de PARP, como gosipol, inhibidor de las interacciones proteína-proteína, son capaces de reducir la actividad transcripcional de E2F-1 y la proli...

Historia como interrupción del tiempo

OpenAIRE

Aguilera Pedrosa, Antonio

2006-01-01

Frente a un concepto de presente como transición y a otro como repetición, Benjamín elabora uno donde el tiempo se detiene, clave para entender su concepto de historia. La interpretación habitual que separa tiempo histórico de tiempo físico quiere facilitar la comprensión de Benjamin, pero al precio de olvidar ciertas paradojas: la misma detención, la reversibilidad del tiempo, la redención del pasado entero, la invocación de la teología, la posibilidad de un cambio respecto al tiempo natural...

Probability: A Matter of Life and Death

Science.gov (United States)

Hassani, Mehdi; Kippen, Rebecca; Mills, Terence

2016-01-01

Life tables are mathematical tables that document probabilities of dying and life expectancies at different ages in a society. Thus, the life table contains some essential features of the health of a population. Probability is often regarded as a difficult branch of mathematics. Life tables provide an interesting approach to introducing concepts…

An introduction to probability and stochastic processes

CERN Document Server

Melsa, James L

2013-01-01

Geared toward college seniors and first-year graduate students, this text is designed for a one-semester course in probability and stochastic processes. Topics covered in detail include probability theory, random variables and their functions, stochastic processes, linear system response to stochastic processes, Gaussian and Markov processes, and stochastic differential equations. 1973 edition.

AtriplaR/anti-TB combination in TB/HIV patients. Drug in focus

Directory of Open Access Journals (Sweden)

Semvua Hadija H

2011-11-01

Full Text Available Abstract Background Co-administration of anti-tuberculosis and antiretroviral therapy is often inevitable in high-burden countries where tuberculosis is the most common opportunistic infection associated with HIV/AIDS. Concurrent use of rifampicin and several antiretroviral drugs is complicated by pharmacokinetic drug-drug interaction. Method Pubmed and Google search following the key words tuberculosis, HIV, emtricitabine, tenofovir efavirenz, interaction were used to find relevant information on each drug of the fixed dose combination AtriplaR Results Information on generic name, trade name, pharmacokinetic parameter, metabolism and the pharmacokinetic interaction with Anti-TB drugs of emtricitabine, tenofovir, and efavirenz was obtained. Conclusion Fixed dose combination of emtricitabine/tenofovir/efavirenz (ATRIPLAR which has been approved by Food and Drug Administration shows promising results as far as safety and efficacy is concerned in TB/HIV co-infection patients, hence can be considered effective and safe antiretroviral drug in TB/HIV management for adult and children above 3 years of age.

Probability densities and Lévy densities

DEFF Research Database (Denmark)

Barndorff-Nielsen, Ole Eiler

For positive Lévy processes (i.e. subordinators) formulae are derived that express the probability density or the distribution function in terms of power series in time t. The applicability of the results to finance and to turbulence is briefly indicated.......For positive Lévy processes (i.e. subordinators) formulae are derived that express the probability density or the distribution function in terms of power series in time t. The applicability of the results to finance and to turbulence is briefly indicated....

Maximization of regional probabilities using Optimal Surface Graphs

DEFF Research Database (Denmark)

Arias Lorza, Andres M.; Van Engelen, Arna; Petersen, Jens

2018-01-01

Purpose: We present a segmentation method that maximizes regional probabilities enclosed by coupled surfaces using an Optimal Surface Graph (OSG) cut approach. This OSG cut determines the globally optimal solution given a graph constructed around an initial surface. While most methods for vessel...... wall segmentation only use edge information, we show that maximizing regional probabilities using an OSG improves the segmentation results. We applied this to automatically segment the vessel wall of the carotid artery in magnetic resonance images. Methods: First, voxel-wise regional probability maps...... were obtained using a Support Vector Machine classifier trained on local image features. Then, the OSG segments the regions which maximizes the regional probabilities considering smoothness and topological constraints. Results: The method was evaluated on 49 carotid arteries from 30 subjects...

Zero field reversal probability in thermally assisted magnetization reversal

Science.gov (United States)

Prasetya, E. B.; Utari; Purnama, B.

2017-11-01

This paper discussed about zero field reversal probability in thermally assisted magnetization reversal (TAMR). Appearance of reversal probability in zero field investigated through micromagnetic simulation by solving stochastic Landau-Lifshitz-Gibert (LLG). The perpendicularly anisotropy magnetic dot of 50×50×20 nm3 is considered as single cell magnetic storage of magnetic random acces memory (MRAM). Thermally assisted magnetization reversal was performed by cooling writing process from near/almost Curie point to room temperature on 20 times runs for different randomly magnetized state. The results show that the probability reversal under zero magnetic field decreased with the increase of the energy barrier. The zero-field probability switching of 55% attained for energy barrier of 60 k B T and the reversal probability become zero noted at energy barrier of 2348 k B T. The higest zero-field switching probability of 55% attained for energy barrier of 60 k B T which corespond to magnetif field of 150 Oe for switching.

Path probability of stochastic motion: A functional approach

Science.gov (United States)

Hattori, Masayuki; Abe, Sumiyoshi

2016-06-01

The path probability of a particle undergoing stochastic motion is studied by the use of functional technique, and the general formula is derived for the path probability distribution functional. The probability of finding paths inside a tube/band, the center of which is stipulated by a given path, is analytically evaluated in a way analogous to continuous measurements in quantum mechanics. Then, the formalism developed here is applied to the stochastic dynamics of stock price in finance.

Probability and containment of turbine missiles

International Nuclear Information System (INIS)

Yeh, G.C.K.

1976-01-01

With the trend toward ever larger power generating plants with large high-speed turbines, an important plant design consideration is the potential for and consequences of mechanical failure of turbine rotors. Such rotor failure could result in high-velocity disc fragments (turbine missiles) perforating the turbine casing and jeopardizing vital plant systems. The designer must first estimate the probability of any turbine missile damaging any safety-related plant component for his turbine and his plant arrangement. If the probability is not low enough to be acceptable to the regulatory agency, he must design a shield to contain the postulated turbine missiles. Alternatively, the shield could be designed to retard (to reduce the velocity of) the missiles such that they would not damage any vital plant system. In this paper, some of the presently available references that can be used to evaluate the probability, containment and retardation of turbine missiles are reviewed; various alternative methods are compared; and subjects for future research are recommended. (Auth.)

Como aquí, allá; como nosotros, ellos: la internacionalización de la precariedad en el ejercicio ciudadano

Directory of Open Access Journals (Sweden)

Patricia Zamudio Grave

2007-05-01

Full Text Available La universalidad de los derechos humanos ha sido proclamada y reiterada por la comunidad de naciones, desde mediados del siglo veinte. Al mismo tiempo, procesos globalizadores parecen contradecir el derecho de todos los seres humanos a gozar de una vida digna, en todos los aspectos que ésta engloba, tanto en países desarrollados, como en aquéllos en proceso de desarrollo. Este trabajo reflexiona sobre la forma como la migración internacional conecta experiencias de precariedad en el ejercicio de derechos y sus consecuencias para la vida cotidiana de los migrantes.

O neoliberalismo como um dos fundamentos da educação domiciliar

Directory of Open Access Journals (Sweden)

Romualdo Luiz Portela de Oliveira

Full Text Available Resumo Este artigo tem como objetivo analisar o neoliberalismo como um dos fundamentos da educação domiciliar, fenômeno de interesse crescente no Brasil, dada a tentativa de regulamentá-lo no país. Para tanto, foram tomados como referência três autorizados representantes do neoliberalismo: Friedrich Hayek; Milton Friedman e Ludwig von Mises e a reiterada preocupação destes com as liberdades, sobretudo as individuais. O artigo argumenta que o neoliberalismo se apresenta como uma das correntes teóricas que também dá suporte ao homeschooling, tendo como ponto crucial de sua fundamentação a rejeição da compulsoriedade da educação escolar, o que gera fortes implicações para o debate educacional, principalmente como desafios à escola pública compulsória.

NARRATIVAS TRANSMIDIÁTICAS COMO ESTRATÉGIAS PUBLICITÁRIAS

OpenAIRE

Costa, Marcela

2013-01-01

Resumo: O trabalho reflete sobre as narrativas transmidiáticas como estratégiaspublicitárias. Para tal, realizamos um levantamento bibliográfico visandoentender que é uma narrativa, sua estrutura e definir o que são as narrativas transmidáticas. Por fim, analisamos a campanha The Happiness Factory paracompreender se, de fato, as narrativas transmidiáticas têm sido empregadaspela publicidade e como isso ocorre.Palavras-chave: publicidade; narrativa; narrativa transmidiática.Narrativas transmed...

La fenomenología como atavismo

Directory of Open Access Journals (Sweden)

Galán, Iván

2009-04-01

Full Text Available This paper deals with phenomenology as a result of phenomenological freedom in its possibility of understanding a phenomenon as wild phenomenon. From this perspective, we are enabled to transcend established symbolic systems and to pose the question on the existence of a sense which is immature, not-saturated and imperfect without exception.El artículo pretende mostrar la vigencia de la fenomenología como expresión de la libertad fenomenológica, como posibilidad siempre abierta de acceder al fenómeno en cuanto fenómeno puro, registro arquitectónico en el que, saltando por sobre los sistemas simbólicos instituidos, nos es permitido plantear en toda su radicalidad la pregunta por la existencia de un sentido siempre prematuro, no saturado y jamás clausurable.

Estimation of Extreme Response and Failure Probability of Wind Turbines under Normal Operation using Probability Density Evolution Method

DEFF Research Database (Denmark)

Sichani, Mahdi Teimouri; Nielsen, Søren R.K.; Liu, W. F.

2013-01-01

Estimation of extreme response and failure probability of structures subjected to ultimate design loads is essential for structural design of wind turbines according to the new standard IEC61400-1. This task is focused on in the present paper in virtue of probability density evolution method (PDEM......), which underlies the schemes of random vibration analysis and structural reliability assessment. The short-term rare failure probability of 5-mega-watt wind turbines, for illustrative purposes, in case of given mean wind speeds and turbulence levels is investigated through the scheme of extreme value...... distribution instead of any other approximate schemes of fitted distribution currently used in statistical extrapolation techniques. Besides, the comparative studies against the classical fitted distributions and the standard Monte Carlo techniques are carried out. Numerical results indicate that PDEM exhibits...

The probability of the false vacuum decay

International Nuclear Information System (INIS)

Kiselev, V.; Selivanov, K.

1983-01-01

The closed expession for the probability of the false vacuum decay in (1+1) dimensions is given. The probability of false vacuum decay is expessed as the product of exponential quasiclassical factor and a functional determinant of the given form. The method for calcutation of this determinant is developed and a complete answer for (1+1) dimensions is given

Influence of the Probability Level on the Framing Effect

Directory of Open Access Journals (Sweden)

Kaja Damnjanovic

2016-11-01

Full Text Available Research of the framing effect of risky choice mostly applies to the tasks where the effect of only one probability or risk level on the choice of non-risky or risky options was examined. The conducted research was aimed to examine the framing effect in the function of probability level in the outcome of a risk option in three decision-making domains: health, money and human lives. It has been confirmed that the decision-making domain moderates the framing effect. In the monetary domain, the general risk aversion has been confirmed as registered in earlier research. At high probability levels, the framing effect is registered in both frames, while no framing effect is registered at lower probability levels. In the domain of decision-making about human lives, the framing effect is registered at medium high and medium low probability levels. In the domain of decision-making about health, the framing effect is registered almost in the entire probability range while this domain differs from the former two. The results show that the attitude to risk is not identical at different probability levels, that the dynamics of the attitude to risk influences the framing effect, and that the framing effect pattern is different in different decision-making domains. In other words, linguistic manipulation representing the frame in the tasks affects the change in the preference order only when the possibility of gain (expressed in probability is estimated as sufficiently high.

Probability of crack-initiation and application to NDE

Energy Technology Data Exchange (ETDEWEB)

Prantl, G [Nuclear Safety Inspectorate HSK, (Switzerland)

1988-12-31

Fracture toughness is a property with a certain variability. When a statistical distribution is assumed, the probability of crack initiation may be calculated for a given problem defined by its geometry and the applied stress. Experiments have shown, that cracks which experience a certain small amount of ductile growth can reliably be detected by acoustic emission measurements. The probability of crack detection by AE-techniques may be estimated using this experimental finding and the calculated probability of crack initiation. (author).

Introduction to probability and stochastic processes with applications

CERN Document Server

Castañ, Blanco; Arunachalam, Viswanathan; Dharmaraja, Selvamuthu

2012-01-01

An easily accessible, real-world approach to probability and stochastic processes Introduction to Probability and Stochastic Processes with Applications presents a clear, easy-to-understand treatment of probability and stochastic processes, providing readers with a solid foundation they can build upon throughout their careers. With an emphasis on applications in engineering, applied sciences, business and finance, statistics, mathematics, and operations research, the book features numerous real-world examples that illustrate how random phenomena occur in nature and how to use probabilistic t

El Sistema Penal como Instrumento de Control Social: El Papel del Encarcelamiento

Directory of Open Access Journals (Sweden)

Kelly Ribeiro Felix de Souza

2015-12-01

Full Text Available El objetivo de este estudio es analizar el sistema penal con el fin de encontrar elementos capaces de entenderlo como una técnica de control social de los considerados indeseables para la vida en sociedad. Adoptando como marco teórico la criminología crítica, más especificamente las contribuciones de autores como Massimo Pavarini y Michel Foucault, así como el método de investigación dialéctico, se busca, desde un enfoque jurídico y sociológico, indicar las transformaciones del poder disciplinario hasta su diseño actual, así como demostrar sus relaciones con uno de los principales instrumentos del poder punitivo hoy en día - la privación de libertad. En este sentido, parece que la selectividad del ejercicio del poder punitivo se muestra como un importante instrumento de control social de los excluidos.

La docencia como práctica profesional

Directory of Open Access Journals (Sweden)

Martínez de Acosta Carmen H.

1993-12-01

Full Text Available

No es fácil determinar si la actividad docente corresponde o no a una modalidad de práctica, rol, área de desempeño o ejercicio profesional como indiscriminadamente se denomina a las diferentes formas del quehacer de enfermería. Uno de los conceptos básicos de sociología es el de rol. El rol consiste en las conductas cumplidas o conductas percibidas como aceptables, referidas a una situación dada. La identificación de un rol se alcanza por medio de un proceso mutuo de validación y socialización profesional.

Use of probability tables for propagating uncertainties in neutronics

International Nuclear Information System (INIS)

Coste-Delclaux, M.; Diop, C.M.; Lahaye, S.

2017-01-01

Highlights: • Moment-based probability table formalism is described. • Representation by probability tables of any uncertainty distribution is established. • Multiband equations for two kinds of uncertainty propagation problems are solved. • Numerical examples are provided and validated against Monte Carlo simulations. - Abstract: Probability tables are a generic tool that allows representing any random variable whose probability density function is known. In the field of nuclear reactor physics, this tool is currently used to represent the variation of cross-sections versus energy (neutron transport codes TRIPOLI4®, MCNP, APOLLO2, APOLLO3®, ECCO/ERANOS…). In the present article we show how we can propagate uncertainties, thanks to a probability table representation, through two simple physical problems: an eigenvalue problem (neutron multiplication factor) and a depletion problem.

Quantum correlations in terms of neutrino oscillation probabilities

Energy Technology Data Exchange (ETDEWEB)

Alok, Ashutosh Kumar, E-mail: akalok@iitj.ac.in [Indian Institute of Technology Jodhpur, Jodhpur 342011 (India); Banerjee, Subhashish, E-mail: subhashish@iitj.ac.in [Indian Institute of Technology Jodhpur, Jodhpur 342011 (India); Uma Sankar, S., E-mail: uma@phy.iitb.ac.in [Indian Institute of Technology Bombay, Mumbai 400076 (India)

2016-08-15

Neutrino oscillations provide evidence for the mode entanglement of neutrino mass eigenstates in a given flavour eigenstate. Given this mode entanglement, it is pertinent to consider the relation between the oscillation probabilities and other quantum correlations. In this work, we show that all the well-known quantum correlations, such as the Bell's inequality, are directly related to the neutrino oscillation probabilities. The results of the neutrino oscillation experiments, which measure the neutrino survival probability to be less than unity, imply Bell's inequality violation.

Risk Probability Estimating Based on Clustering

DEFF Research Database (Denmark)

Chen, Yong; Jensen, Christian D.; Gray, Elizabeth

2003-01-01

of prior experiences, recommendations from a trusted entity or the reputation of the other entity. In this paper we propose a dynamic mechanism for estimating the risk probability of a certain interaction in a given environment using hybrid neural networks. We argue that traditional risk assessment models...... from the insurance industry do not directly apply to ubiquitous computing environments. Instead, we propose a dynamic mechanism for risk assessment, which is based on pattern matching, classification and prediction procedures. This mechanism uses an estimator of risk probability, which is based...

Duelling idiots and other probability puzzlers

CERN Document Server

Nahin, Paul J

2002-01-01

What are your chances of dying on your next flight, being called for jury duty, or winning the lottery? We all encounter probability problems in our everyday lives. In this collection of twenty-one puzzles, Paul Nahin challenges us to think creatively about the laws of probability as they apply in playful, sometimes deceptive, ways to a fascinating array of speculative situations. Games of Russian roulette, problems involving the accumulation of insects on flypaper, and strategies for determining the odds of the underdog winning the World Series all reveal intriguing dimensions to the worki

Efavirenz or nevirapine in three-drug combination therapy with two nucleoside or nucleotide-reverse transcriptase inhibitors for initial treatment of HIV infection in antiretroviral-naïve individuals.

Science.gov (United States)

Mbuagbaw, Lawrence; Mursleen, Sara; Irlam, James H; Spaulding, Alicen B; Rutherford, George W; Siegfried, Nandi

2016-12-10

The advent of highly active antiretroviral therapy (ART) has reduced the morbidity and mortality due to HIV infection. The World Health Organization (WHO) ART guidelines focus on three classes of antiretroviral drugs, namely nucleoside or nucleotide reverse transcriptase inhibitors (NRTI), non-nucleoside reverse transcriptase inhibitors (NNRTI) and protease inhibitors. Two of the most common medications given as first-line treatment are the NNRTIs, efavirenz (EFV) and nevirapine (NVP). It is unclear which NNRTI is more efficacious for initial therapy. This systematic review was first published in 2010. To determine which non-nucleoside reverse transcriptase inhibitor, either EFV or NVP, is more effective in suppressing viral load when given in combination with two nucleoside reverse transcriptase inhibitors as part of initial antiretroviral therapy for HIV infection in adults and children. We attempted to identify all relevant studies, regardless of language or publication status, in electronic databases and conference proceedings up to 12 August 2016. We searched MEDLINE, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL), the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) and ClinicalTrials.gov to 12 August 2016. We searched LILACS (Latin American and Caribbean Health Sciences Literature) and the Web of Science from 1996 to 12 August 2016. We checked the National Library of Medicine (NLM) Gateway from 1996 to 2009, as it was no longer available after 2009. We included all randomized controlled trials (RCTs) that compared EFV to NVP in people with HIV without prior exposure to ART, irrespective of the dosage or NRTI's given in combination.The primary outcome of interest was virological success. Other primary outcomes included mortality, clinical progression to AIDS, severe adverse events, and discontinuation of therapy for any reason. Secondary outcomes were change in CD4 count, treatment failure

El dictado como tarea comunicativa

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Daniel Cassany

2004-01-01

Full Text Available El artículo explora las utilidades didácticas del dictado (la práctica comunicativa de oralizar o leer en voz alta un escrito para el aprendizaje funcional de una lengua materna o extranjera, en los diversos niveles de enseñanza. Después de criticar el uso tradicional de este ejercicio lingüístico, presentamos once formas diferentes de desarrollar un dictado en clase, con sus particulares contenidos, objetivos y metodologías. También analizamos con detalle la técnica más tradicional del dictado magistral, en la que el docente dicta palabra por palabra un texto al alumnado, poniendo énfasis en la ortografía; ofrecemos algunas orientaciones para incrementar el componente comunicativo de esta propuesta. Las conclusiones finales proponen entender esta técnica como un recurso metodológico variado, rico y sugerente, adaptado a cada situación de aprendizaje —y no como una práctica obligatoria y fosilizada.

Virological failure of staggered and simultaneous treatment interruption in HIV patients who began Efavirenz-based regimens after allergic reactions to nevirapine

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Siripassorn Krittaecho

2013-01-01

Full Text Available Abstract Objective The objective of this work was to study the virological outcomes associated with two different types of treatment interruption strategies in patients with allergic reactions to nevirapine (NVP. We compared the virological outcomes of (1 HIV-1-infected patients who discontinued an initial NVP-based regimen because of cutaneous allergic reactions to NVP; different types of interruption strategies were used, and second-line regimen was based on efavirenz (EFV; and (2 HIV-1-infected patients who began an EFV-based regimen as a first-line therapy (controls. Methods This retrospective cohort included patients who began an EFV-based regimen, between January 2002 and December 2008, as either an initial regimen or as a subsequent regimen after resolving a cutaneous allergic reaction against an initial NVP-based regimen. The study ended in March 2010. The primary outcome was virological failure, which was defined as either (a two consecutive plasma HIV-1 RNA levels >400 copies/mL or (b a plasma HIV-1 RNA level >1,000 copies/mL plus any genotypic resistance mutation. Results A total of 559 patients were stratified into three groups: (a Simultaneous Interruption, in which the subjects simultaneously discontinued all the drugs in an NVP-based regimen following an allergic reaction (n=161; (b Staggered Interruption, in which the subjects discontinued NVP treatment while continuing nucleoside reverse transcriptase inhibitor (NRTI backbone therapy for a median of 7 days (n=82; and (c Control, in which the subjects were naïve to antiretroviral therapy (n=316. The overall median follow-up time was 43 months. Incidence of virological failure in Simultaneous Interruption was 12.9 cases per 1,000 person-years, which trended toward being higher than the incidences in Staggered Interruption (5.4 and Control (6.6. However, differences were not statistically significant. Conclusions Among the patients who had an acute allergic reaction to first

EARLY HISTORY OF GEOMETRIC PROBABILITY AND STEREOLOGY

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Magdalena Hykšová

2012-03-01

Full Text Available The paper provides an account of the history of geometric probability and stereology from the time of Newton to the early 20th century. It depicts the development of two parallel ways: on one hand, the theory of geometric probability was formed with minor attention paid to other applications than those concerning spatial chance games. On the other hand, practical rules of the estimation of area or volume fraction and other characteristics, easily deducible from geometric probability theory, were proposed without the knowledge of this branch. A special attention is paid to the paper of J.-É. Barbier published in 1860, which contained the fundamental stereological formulas, but remained almost unnoticed both by mathematicians and practicians.

Estimation of post-test probabilities by residents: Bayesian reasoning versus heuristics?

Science.gov (United States)

Hall, Stacey; Phang, Sen Han; Schaefer, Jeffrey P; Ghali, William; Wright, Bruce; McLaughlin, Kevin

2014-08-01

Although the process of diagnosing invariably begins with a heuristic, we encourage our learners to support their diagnoses by analytical cognitive processes, such as Bayesian reasoning, in an attempt to mitigate the effects of heuristics on diagnosing. There are, however, limited data on the use ± impact of Bayesian reasoning on the accuracy of disease probability estimates. In this study our objective was to explore whether Internal Medicine residents use a Bayesian process to estimate disease probabilities by comparing their disease probability estimates to literature-derived Bayesian post-test probabilities. We gave 35 Internal Medicine residents four clinical vignettes in the form of a referral letter and asked them to estimate the post-test probability of the target condition in each case. We then compared these to literature-derived probabilities. For each vignette the estimated probability was significantly different from the literature-derived probability. For the two cases with low literature-derived probability our participants significantly overestimated the probability of these target conditions being the correct diagnosis, whereas for the two cases with high literature-derived probability the estimated probability was significantly lower than the calculated value. Our results suggest that residents generate inaccurate post-test probability estimates. Possible explanations for this include ineffective application of Bayesian reasoning, attribute substitution whereby a complex cognitive task is replaced by an easier one (e.g., a heuristic), or systematic rater bias, such as central tendency bias. Further studies are needed to identify the reasons for inaccuracy of disease probability estimates and to explore ways of improving accuracy.

Illustrating Probability through Roulette: A Spreadsheet Simulation Model

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Kala Chand Seal

2005-11-01

Full Text Available Teaching probability can be challenging because the mathematical formulas often are too abstract and complex for the students to fully grasp the underlying meaning and effect of the concepts. Games can provide a way to address this issue. For example, the game of roulette can be an exciting application for teaching probability concepts. In this paper, we implement a model of roulette in a spreadsheet that can simulate outcomes of various betting strategies. The simulations can be analyzed to gain better insights into the corresponding probability structures. We use the model to simulate a particular betting strategy known as the bet-doubling, or Martingale, strategy. This strategy is quite popular and is often erroneously perceived as a winning strategy even though the probability analysis shows that such a perception is incorrect. The simulation allows us to present the true implications of such a strategy for a player with a limited betting budget and relate the results to the underlying theoretical probability structure. The overall validation of the model, its use for teaching, including its application to analyze other types of betting strategies are discussed.

Tumor control probability after a radiation of animal tumors

International Nuclear Information System (INIS)

Urano, Muneyasu; Ando, Koichi; Koike, Sachiko; Nesumi, Naofumi

1975-01-01

Tumor control and regrowth probability of animal tumors irradiated with a single x-ray dose were determined, using a spontaneous C3H mouse mammary carcinoma. Cellular radiation sensitivity of tumor cells and tumor control probability of the tumor were examined by the TD 50 and TCD 50 assays respectively. Tumor growth kinetics were measured by counting the percentage of labelled mitosis and by measuring the growth curve. A mathematical analysis of tumor control probability was made from these results. A formula proposed, accounted for cell population kinetics or division probability model, cell sensitivity to radiation and number of tumor cells. (auth.)

Pegada Hídrica como Indicador de Sustentabilidade Ambiental1

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Kettrin Farias Bem Maracajá

2012-08-01

Full Text Available O conceito de pegada hídrica tem sido recentemente introduzido como um importante indicador do consumo de água humano, na tentativa de minimizar os impactos ambientais. Esse trabalho aborda o conceito da pegada hídrica como um indicador de sustentabilidade, com vistas o uso racional dos recursos hídricos. Nos últimos anos, a escassez de alguns recursos naturais vem sendo bastante discutido em todo o mundo e quanto à água a preocupação é ainda maior em face do uso desordenado na irrigação, bem como pela poluição da água potável através da indústria e agricultura. Partindo dessa análise, a pegada hídrica surge como um indicador de sustentabilidade da água doce em seus diferentes tipos de consumo para que seja utilizada de forma consciente. Com base na revisão da literatura sobre o tema abordado, conclui-se que para a redução da pegada hídrica se deve tomar medidas de controle do uso direto e indireto da água doce principalmente na agricultura irrigada.

Joseph L Doob and Development of Probability Theory

Indian Academy of Sciences (India)

IAS Admin

(equivalent to BSc in India) in mathematics at the famous Harvard University, ... Doob says that the force of economic circumstances got him into probability theory. ... Books. J L Doob established probability theory as a major discipline of study ...

LA CTE "OTTO PARELLADA" (TALLAPIEDRA COMO BASE MATERIAL DE ESTUDIO

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Alberto E Calvo González

2011-03-01

Full Text Available Se presenta el análisis de las posibilidades que tiene la CTE" Otto Parellada" como elemento fundamental en la formación de ingenieros electricistas, así como para otras especialidades.Se expone el modo en que actualmente se le aprovecha para la carrera de Ingeniería Eléctrica en ladisciplina de Centrales Termoeléctricas, así como para la carrera de Ingeniería Mecánica en la asignatura homónimadel 1er. año. Se exponen otras posibilidades de la planta que podrían ser explotadas aún por otras carreras comoArquitectura, al tener características que la avalan como Patrimonio Industrial.  In this paper is presented the analysis of the possibilities like fundamental element that Otto Parellada SteamPower Plant has for the electrical, as well as other specialties engineers' syllabus. The way that at present time isused for the electrical engineers education, in the thermal engineering subjects is exposed, as well as for themechanical engineering in the 1st year. Other possibilities of the plant that could still be exploited by otherscareers like architecture, due to the characteristic that endorse it as Industrial Patrimony are also exposed.

Tuned by experience: How orientation probability modulates early perceptual processing.

Science.gov (United States)

Jabar, Syaheed B; Filipowicz, Alex; Anderson, Britt

2017-09-01

Probable stimuli are more often and more quickly detected. While stimulus probability is known to affect decision-making, it can also be explained as a perceptual phenomenon. Using spatial gratings, we have previously shown that probable orientations are also more precisely estimated, even while participants remained naive to the manipulation. We conducted an electrophysiological study to investigate the effect that probability has on perception and visual-evoked potentials. In line with previous studies on oddballs and stimulus prevalence, low-probability orientations were associated with a greater late positive 'P300' component which might be related to either surprise or decision-making. However, the early 'C1' component, thought to reflect V1 processing, was dampened for high-probability orientations while later P1 and N1 components were unaffected. Exploratory analyses revealed a participant-level correlation between C1 and P300 amplitudes, suggesting a link between perceptual processing and decision-making. We discuss how these probability effects could be indicative of sharpening of neurons preferring the probable orientations, due either to perceptual learning, or to feature-based attention. Copyright © 2017 Elsevier Ltd. All rights reserved.

Predicting Cumulative Incidence Probability: Marginal and Cause-Specific Modelling

DEFF Research Database (Denmark)

Scheike, Thomas H.; Zhang, Mei-Jie

2005-01-01

cumulative incidence probability; cause-specific hazards; subdistribution hazard; binomial modelling......cumulative incidence probability; cause-specific hazards; subdistribution hazard; binomial modelling...

El anisakis y sus enfermedades como enfermedad profesional

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José Manuel Vicente Pardo

Full Text Available El anisakis es un parásito complejo de los animales marinos. El hombre no es el hospedador adecuado, ya que en él la larva L3 no puede completar su ciclo vital, siendo por tanto un hospedador accidental u ocasional, que se interpone en el ciclo vital del nemátodo, y al que el anisakis le puede causar tanto la parasitación como la alergia, cuando ingiere pescado o cefalópodos crudos o poco cocinados: tales como sushi, sashimi, ceviche gravlax noruego, lomi-lomi hawaiano, así como pescados en escabeche, vinagre, desecado, ahumados, semiconservas, o en salazón que contengan este parásito en su forma de larva en estadio tres L3. Las enfermedades por anisakis constituyen un problema de salud pública, generalizado y que ha aumentado su incidencia en los últimos años. En 2012, se notificaron 20.000 casos de anisakiasis en todo el mundo. España es el segundo país con mayor número de intoxicaciones por Anisakis después de Japón. Diversos estudios en España sobre la prevalencia de la sensibilización reflejan una elevada prevalencia entre pacientes que han sufrido episodios de reacciones alérgicas. El 50 por ciento de quienes manipulan directamente el pescado presentan sensibilidad a anisakis. Siendo por tanto cada vez más común la afectación por y en el desarrollo del trabajo, constituyendo entonces procesos considerados como enfermedad profesional cuando se dan las circunstancias determinantes causales de trabajo, riesgo y exposición que para ello deben concurrir. La afección puede presentarse tanto por contacto laboral como por contacto en el consumo ordinario de pescado infestado, lo que hará difícil el estimar como causa exclusiva o consecuente la aparición de la enfermedad a consecuencia del desempeño del trabajo. Los sectores laborales de riesgo por enfermedades por anisakis, son los pescadores, pescaderos ("pescateros" y cocineros. En general todos aquellos que trabajan tanto en la captura, limpieza, manipulación, venta

Probability for Weather and Climate

Science.gov (United States)

Smith, L. A.

2013-12-01

Over the last 60 years, the availability of large-scale electronic computers has stimulated rapid and significant advances both in meteorology and in our understanding of the Earth System as a whole. The speed of these advances was due, in large part, to the sudden ability to explore nonlinear systems of equations. The computer allows the meteorologist to carry a physical argument to its conclusion; the time scales of weather phenomena then allow the refinement of physical theory, numerical approximation or both in light of new observations. Prior to this extension, as Charney noted, the practicing meteorologist could ignore the results of theory with good conscience. Today, neither the practicing meteorologist nor the practicing climatologist can do so, but to what extent, and in what contexts, should they place the insights of theory above quantitative simulation? And in what circumstances can one confidently estimate the probability of events in the world from model-based simulations? Despite solid advances of theory and insight made possible by the computer, the fidelity of our models of climate differs in kind from the fidelity of models of weather. While all prediction is extrapolation in time, weather resembles interpolation in state space, while climate change is fundamentally an extrapolation. The trichotomy of simulation, observation and theory which has proven essential in meteorology will remain incomplete in climate science. Operationally, the roles of probability, indeed the kinds of probability one has access too, are different in operational weather forecasting and climate services. Significant barriers to forming probability forecasts (which can be used rationally as probabilities) are identified. Monte Carlo ensembles can explore sensitivity, diversity, and (sometimes) the likely impact of measurement uncertainty and structural model error. The aims of different ensemble strategies, and fundamental differences in ensemble design to support of

Cultura e natureza: a viagem e o turismo como necessidades humanas

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Silvio Lima Figueiredo

2014-12-01

Full Text Available O artigo analisa os conceitos e práticas da viagem e do turismo baseado nas discussões sobre as características do fenômeno e de sua gênese. A viagem é então entendida a partir dos estudos da natureza e da cultura e como essas duas categorias se relacionam entre si, de acordo com os estudos antropológicos de Malinowski, Claude Levi-Strauss e Clifford Geertz. É evidenciada a interpretação da viagem como universal cultural, no entanto, nao se pode entendê-la como um aspecto da “natureza humana”. O turismo é entendido como um tipo de viagem cuja origem e características surgiram no mundo moderno.

Probability analysis of nuclear power plant hazards

International Nuclear Information System (INIS)

Kovacs, Z.

1985-01-01

The probability analysis of risk is described used for quantifying the risk of complex technological systems, especially of nuclear power plants. Risk is defined as the product of the probability of the occurrence of a dangerous event and the significance of its consequences. The process of the analysis may be divided into the stage of power plant analysis to the point of release of harmful material into the environment (reliability analysis) and the stage of the analysis of the consequences of this release and the assessment of the risk. The sequence of operations is characterized in the individual stages. The tasks are listed which Czechoslovakia faces in the development of the probability analysis of risk, and the composition is recommended of the work team for coping with the task. (J.C.)

SureTrak Probability of Impact Display

Science.gov (United States)

Elliott, John

2012-01-01

The SureTrak Probability of Impact Display software was developed for use during rocket launch operations. The software displays probability of impact information for each ship near the hazardous area during the time immediately preceding the launch of an unguided vehicle. Wallops range safety officers need to be sure that the risk to humans is below a certain threshold during each use of the Wallops Flight Facility Launch Range. Under the variable conditions that can exist at launch time, the decision to launch must be made in a timely manner to ensure a successful mission while not exceeding those risk criteria. Range safety officers need a tool that can give them the needed probability of impact information quickly, and in a format that is clearly understandable. This application is meant to fill that need. The software is a reuse of part of software developed for an earlier project: Ship Surveillance Software System (S4). The S4 project was written in C++ using Microsoft Visual Studio 6. The data structures and dialog templates from it were copied into a new application that calls the implementation of the algorithms from S4 and displays the results as needed. In the S4 software, the list of ships in the area was received from one local radar interface and from operators who entered the ship information manually. The SureTrak Probability of Impact Display application receives ship data from two local radars as well as the SureTrak system, eliminating the need for manual data entry.

LA PARTICIPACION EN LA SOCIEDAD COMO BASE DEL DESARROLLO

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María Cecilia Múnera López

2012-11-01

Full Text Available A explicação dela participação na sociedade como a base para o desenvolvimento é o resultado dum processo longo de pesquisa, que no âmbito da teoria fundamentada, tem chegado a aspetos essenciais de ordem conceitual e metodológica, que sustentam o desenvolvimento e a participação. Assim, este artigo apresenta o desenvolvimento desde uma perspectiva resignificada, entendida como uma construção sociocultural múltipla, histórica e territorialmente determinada. De acordo com tal renovação teórica, se apresenta uma forma tipológica de participação, chamada "participação sinérgica", como uma opção plausível para impactar positivamente o desenvolvimento.

Quantum probability and quantum decision-making.

Science.gov (United States)

Yukalov, V I; Sornette, D

2016-01-13

A rigorous general definition of quantum probability is given, which is valid not only for elementary events but also for composite events, for operationally testable measurements as well as for inconclusive measurements, and also for non-commuting observables in addition to commutative observables. Our proposed definition of quantum probability makes it possible to describe quantum measurements and quantum decision-making on the same common mathematical footing. Conditions are formulated for the case when quantum decision theory reduces to its classical counterpart and for the situation where the use of quantum decision theory is necessary. © 2015 The Author(s).

Lady luck the theory of probability

CERN Document Server

Weaver, Warren

1982-01-01

""Should I take my umbrella?"" ""Should I buy insurance?"" ""Which horse should I bet on?"" Every day ― in business, in love affairs, in forecasting the weather or the stock market questions arise which cannot be answered by a simple ""yes"" or ""no."" Many of these questions involve probability. Probabilistic thinking is as crucially important in ordinary affairs as it is in the most abstruse realms of science. This book is the best nontechnical introduction to probability ever written. Its author, the late Dr. Warren Weaver, was a professor of mathematics, active in the Rockefeller and Sloa

Bayesian estimation of core-melt probability

International Nuclear Information System (INIS)

Lewis, H.W.

1984-01-01

A very simple application of the canonical Bayesian algorithm is made to the problem of estimation of the probability of core melt in a commercial power reactor. An approximation to the results of the Rasmussen study on reactor safety is used as the prior distribution, and the observation that there has been no core melt yet is used as the single experiment. The result is a substantial decrease in the mean probability of core melt--factors of 2 to 4 for reasonable choices of parameters. The purpose is to illustrate the procedure, not to argue for the decrease

El Leasing como herramienta de financiación

OpenAIRE

Chorén, María Cecilia

2015-01-01

El siguiente trabajo de investigación es planteado para ser utilizado por las Pymes para evaluar la oportunidad de aplicar el Leasing frente a una posibilidad de inversión en activos fijos; ya que hoy en día es tenido en cuenta en los países desarrollados como la herramienta de financiamiento más conveniente y perfecto que existe debido a sus amplios beneficios. Este trabajo tiene como objetivo primordial establecer las ventajas impositivas, jurídicas, financieras y operativas para que las...

La entrevista como encuentro de subjetividades

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Emma Ruiz Martín del Campo

2003-01-01

Full Text Available Se parte de la comprensión de la subjetividad como la expresión preñada de cultura de cada ser humano que se gesta en las relaciones interpersonales, primero entre el infante y las personas que le prodigan los cuidados tempranos, y después en la adolescencia y la edad adulta, con cada vez más representantes de la cultura de la socialización. En dicha interacción, la persona aprende a convivir con otros y a modelar sus impulsos, lo que le permite encontrar las formas más satisfactorias posibles de experimentarse a sí misma y tomar parte en las actividades de su entorno social. El equilibrio entre el individuo que busca satisfacer sus impulsos y necesidades y la cultura a la que pertenece es dinámico, por lo que la subjetividad se transforma a lo largo de toda la vida. Tras abundar sobre la subjetividad, se describen dos formas de orientar la entrevista a profundidad: la psicoanalítica y la etnopsicoanalítica. La entrevista psicoanalítica explora la subjetividad como tal y en ella el entrevistador actúa como un acompañante del sujeto en la progresiva comprensión de sí mismo y de su historia individual, desentrañando significados del comportamiento hasta entonces inconscientes para sí mismo, que se clarifican en la interacción. La entrevista etnopiscoanalítica busca explorar la experiencia cultural de las personas. Expertos en ciencias sociales entrenados a la vez en el descubrimiento del inconsciente se involucran en un medio cultural nuevo para ellos y a través de entrevistas y conversaciones con los integrantes de la comunidad que visitan van descubriendo formas de participación de estos en los espacios de vida social, así como las maneras que dan cuenta de símbolos y modos de reacción propios de su cultura. Cada una de estas dos formas de entrevista es ilustrada con un ejemplo que da muestra plásticamente del encuentro de las subjetividades

Escape and transmission probabilities in cylindrical geometry

International Nuclear Information System (INIS)

Bjerke, M.A.

1980-01-01

An improved technique for the generation of escape and transmission probabilities in cylindrical geometry was applied to the existing resonance cross section processing code ROLAIDS. The algorithm of Hwang and Toppel, [ANL-FRA-TM-118] (with modifications) was employed. The probabilities generated were found to be as accurate as those given by the method previously applied in ROLAIDS, while requiring much less computer core storage and CPU time

Las fortalezas en personas mayores como factor que aumenta el bienestar

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Encarnación Ramírez-Fernández

2015-08-01

Full Text Available En las últimas décadas se ha incrementado el estudio de las fortalezas psicológicas como factor que afecta al bienestar. Éstas pueden ser consideradas como un subconjunto de rasgos de personalidad a los que se otorga un valor moral, definiéndose como cualidades naturales que las personas están intrínsecamente motivada a utilizar porque aumentan la calidad de vida. Las investigaciones demuestran que actúan como factores de protección y prevención de la psicopatología y de los problemas de conducta en las diferentes etapas evolutivas. Hay fortalezas que son más relevantes en personas mayores y su entrenamiento estaría dirigido a influir sobre el comportamiento y el funcionamiento emocional con el objetivo de aumentar la satisfacción con la vida. En el presente trabajo se analizan las fortalezas que predominan en adultos mayores y se propone un programa de intervención para potenciarlas con la finalidad de mejorar su salud y calidad de vida. Se trata de una propuesta novedosa ya que, hasta el momento, las intervenciones en este ámbito han ido encaminadas a paliar diferentes problemas tanto de manera aislada como complemento de terapias de tipo más tradicional pero no como prevención de la aparición de trastornos habituales en edades avanzadas.

AFINAL, COMO SE FORMAM AS ESTRATÉGIAS?

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Maurício Fernandes Pereira

2007-12-01

Full Text Available Tem havido recentemente um grande interesse por parte dos autores em entender como se desenvolve a prática da estratégia organizacional. Partindo desta tendência, o presente trabalho descreve como ocorre o processo de formação estratégica em uma organização pertencente ao terceiro setor – o SESC/SC (Serviço Social do Comércio em Santa Catarina. A criação da estratégia na organização em estudo é analisada tomando-se como base os referenciais propostos por Whittington (2002, analisando duas dimensões principais: os resultados pretendidos com as estratégias e os processos pelos quais ela acontece. Com base nos dados coletados observou-se que, na prática da organização pesquisada, as razões que levam ao estabelecimento da estratégia não estão unicamente voltadas aos aspectos econômicos. Quanto à formação das estratégias, no caso estudado, predominou a formação da estratégia da visão clássica de Whittington (2002, por meio da utilização do planejamento estratégico.

Method to Calculate Accurate Top Event Probability in a Seismic PSA

Energy Technology Data Exchange (ETDEWEB)

Jung, Woo Sik [Sejong Univ., Seoul (Korea, Republic of)

2014-05-15

ACUBE(Advanced Cutset Upper Bound Estimator) calculates the top event probability and importance measures from cutsets by dividing cutsets into major and minor groups depending on the cutset probability, where the cutsets that have higher cutset probability are included in the major group and the others in minor cutsets, converting major cutsets into a Binary Decision Diagram (BDD). By applying the ACUBE algorithm to the seismic PSA cutsets, the accuracy of a top event probability and importance measures can be significantly improved. ACUBE works by dividing the cutsets into two groups (higher and lower cutset probability groups), calculating the top event probability and importance measures in each group, and combining the two results from the two groups. Here, ACUBE calculates the top event probability and importance measures of the higher cutset probability group exactly. On the other hand, ACUBE calculates these measures of the lower cutset probability group with an approximation such as MCUB. The ACUBE algorithm is useful for decreasing the conservatism that is caused by approximating the top event probability and importance measure calculations with given cutsets. By applying the ACUBE algorithm to the seismic PSA cutsets, the accuracy of a top event probability and importance measures can be significantly improved. This study shows that careful attention should be paid and an appropriate method be provided in order to avoid the significant overestimation of the top event probability calculation. Due to the strength of ACUBE that is explained in this study, the ACUBE became a vital tool for calculating more accurate CDF of the seismic PSA cutsets than the conventional probability calculation method.

Joint Probability Distributions for a Class of Non-Markovian Processes

OpenAIRE

Baule, A.; Friedrich, R.

2004-01-01

We consider joint probability distributions for the class of coupled Langevin equations introduced by Fogedby [H.C. Fogedby, Phys. Rev. E 50, 1657 (1994)]. We generalize well-known results for the single time probability distributions to the case of N-time joint probability distributions. It is shown that these probability distribution functions can be obtained by an integral transform from distributions of a Markovian process. The integral kernel obeys a partial differential equation with fr...

El silencio como estrategia en la obra de Juan Rulfo

OpenAIRE

Gómez López-Quiñones, Loreto

2013-01-01

Juan Rulfo utiliza el silencio como un espacio para oír y decir mejor en el contexto del México postrevolucionario. Inspirándonos en la terminología de Spivak, pretendemos mostrar el silencio de Rulfo como una estrategia de resistencia ante la representación occidental del Otro.

Bounding probabilistic safety assessment probabilities by reality

International Nuclear Information System (INIS)

Fragola, J.R.; Shooman, M.L.

1991-01-01

The investigation of the failure in systems where failure is a rare event makes the continual comparisons between the developed probabilities and empirical evidence difficult. The comparison of the predictions of rare event risk assessments with historical reality is essential to prevent probabilistic safety assessment (PSA) predictions from drifting into fantasy. One approach to performing such comparisons is to search out and assign probabilities to natural events which, while extremely rare, have a basis in the history of natural phenomena or human activities. For example the Segovian aqueduct and some of the Roman fortresses in Spain have existed for several millennia and in many cases show no physical signs of earthquake damage. This evidence could be used to bound the probability of earthquakes above a certain magnitude to less than 10 -3 per year. On the other hand, there is evidence that some repetitive actions can be performed with extremely low historical probabilities when operators are properly trained and motivated, and sufficient warning indicators are provided. The point is not that low probability estimates are impossible, but continual reassessment of the analysis assumptions, and a bounding of the analysis predictions by historical reality. This paper reviews the probabilistic predictions of PSA in this light, attempts to develop, in a general way, the limits which can be historically established and the consequent bounds that these limits place upon the predictions, and illustrates the methodology used in computing such limits. Further, the paper discusses the use of empirical evidence and the requirement for disciplined systematic approaches within the bounds of reality and the associated impact on PSA probabilistic estimates