Gabrielle Kelly - Academia.edu (original) (raw)
Papers by Gabrielle Kelly
The American review of respiratory disease, 1982
The thermodilution (TD) method of determining cardiac output (CO) is widely used in clinical prac... more The thermodilution (TD) method of determining cardiac output (CO) is widely used in clinical practice, but its reliability in this setting is not well understood and may be poor. This is especially true when dealing with unstable patients and using commercial TD devices. Numerous published reports have shown markedly variable results when comparing simultaneously the TD method and the Fick or dye-dilution methods in catheterization laboratories, intensive care units, or operating rooms. In order to assist clinicians in interpreting the reliability of the TD method in measuring CO, we analyzed all available published data (14 reports). The differing results in these reports were evaluated by standard statistical methods and by an extension of the influence function method of structural analysis developed to differentiate reproducibility and accuracy errors of each technique. Comparing the accuracy of the TD method with that of the Fick or the dye-dilution methods reveals that the 3 m...
The American review of respiratory disease, 1982
The thermodilution (TD) method of determining cardiac output (CO) is widely used in clinical prac... more The thermodilution (TD) method of determining cardiac output (CO) is widely used in clinical practice, but its reliability in this setting is not well understood and may be poor. This is especially true when dealing with unstable patients and using commercial TD devices. Numerous published reports have shown markedly variable results when comparing simultaneously the TD method and the Fick or dye-dilution methods in catheterization laboratories, intensive care units, or operating rooms. In order to assist clinicians in interpreting the reliability of the TD method in measuring CO, we analyzed all available published data (14 reports). The differing results in these reports were evaluated by standard statistical methods and by an extension of the influence function method of structural analysis developed to differentiate reproducibility and accuracy errors of each technique. Comparing the accuracy of the TD method with that of the Fick or the dye-dilution methods reveals that the 3 m...
Irish Journal of Medical Science, 1986
Epidemiology and Infection, 2007
SUMMARYAn observational study was carried out, using data collected from four areas in the Irish ... more SUMMARYAn observational study was carried out, using data collected from four areas in the Irish midlands, between 1989 and 2004, to critically evaluate the long-term effects of proactive badger culling and to provide insights into reactive badger culling tuberculosis (TB) prevalence in cattle. Confirmed cattle herd TB incidence is the outcome measure used throughout. Relative to reactive culling, proactive badger culling was associated with a decrease in incidence in each of the 16 years of observation, which encompassed periods of both intensive and less-intensive badger removal. By 2004, we observed a decrease of 22% [95% confidence interval (CI) 15–29, P<0·001] in the entire proactive and 37% (95% CI 25–47, P<0·001), in the inner proactive removal areas. The size of the decrease increased with time (P=0·055). There was a decrease (constant over time) of at least 14% (95% CI 76–97, P=0·013) in incidence in the inner compared to the outer control area (herds ⩽2 km, >2 km,...
The general form of the change-point problem is to determine the unknown location τ , based on an... more The general form of the change-point problem is to determine the unknown location τ , based on an ordered sequence of observations x 1 ,. .. , x n , such that the two groups of observations x 1 ,. .. , x τ and x τ +1 ,. .. , x n follow distinct models. We consider the two-phase regression model where x 1 ,. .. , x n follow a model β 01 + β 11 t, for some predictor variable t, and x τ +1 ,. .. , x n follow another model β 02 + β 12 t. There is an extensive statistical literature on this problem. An overview may be found in Carlstein et al. [1]. We use novel statistical methodology of hidden Markov models to determine the existence of a change-point. We use time series models, to estimate the position of the change-point. This extends the work of Kelly et al. [2]. In these models distributions other than the multivariate normal i.e. the multivariate power exponential distribution and the asymmetric multivariate Laplace distribution are considered. The variance may change with the location regression function and this is also incorporated in these models. The results are illustrated using gas exchange data from physiology as in Kelly et al. [3]. The scope for applications also includes drug compliance [4]; in veterinary epidemiology and biology change-point estimation has been used to find seasonal variation; Hall and Titterington [5] list applications from the engineering point of view in computer vision, computer graphics, signal processing, image processing, pattern recognition, geology etc.; Brown et al. [6] applied change-point methods in the field of economics.
A simulation study is implemented to study estimators of the covariance structure of a stationary... more A simulation study is implemented to study estimators of the covariance structure of a stationary Gaussian spatial process and a spatial process with t-distributed margins. The estimators compared are Gaussian restricted maximum likelihood (REML) and curve-fitting by ordinary least squares and by the nonparametric Shapiro-Botha approach. Processes with Matérn covariance functions are considered and the parameters estimated are the nugget, partial sill and practical range. Both parametric and nonparametric bootstrap distributions of the estimators are computed and compared to the true marginal distributions of the estimators. Gaussian REML is the estimator of choice for both Gaussian and t-distributed data and all choices of the Matérn covariance structure. However, accurate estimation of the Matérn shape parameter is critical to achieving a good fit while this does not affect the Shapiro-Botha estimator. The parametric bootstrap performed well for all estimators although it tended t...
Evidence that more people in some countries and fewer in others are dying because of the pandemic... more Evidence that more people in some countries and fewer in others are dying because of the pandemic, than is reflected by reported Covid-19 mortality rates, is derived from mortality data. Using publicly available databases, deaths attributed to Covid-19 in 2020 and all deaths for the years 2015-2020 were tabulated for 35 countries together with economic, health, demographic, and government response stringency index variables. Residual mortality rates (RMR) in 2020 were calculated as excess mortality minus reported mortality rates due to Covid-19 where excess deaths were observed deaths in 2020 minus the average for 2015-2019. Differences in RMR are differences not attributed to reported Covid-19. For about half the countries, RMR’s were negative and for half, positive. The absolute rates in some countries were double those in others. In a regression analysis, population density and proportion of female smokers were positively associated with both Covid-19 and excess mortality while t...
Veterinary and Comparative Orthopaedics and Traumatology, 2020
Objective The aim of this study was to measure the load on the lateral and medial aspects of the ... more Objective The aim of this study was to measure the load on the lateral and medial aspects of the proximal radio-ulnar joint during extension of the carpus. Study Design This was an ex vivo biomechanical study. Sample Population Twenty-two cadaveric Greyhound thoracic limbs were used. Methods Twenty-two paired thoracic limbs were used. The olecranon was attached to a custom jig with the foot resting on a stationary anvil. Load sensors were inserted into the proximal radio-ulnar joint, between the radial head and the lateral coronoid process, and between the radial head and the medial coronoid process. Specimens were tested under compression with measurements taken at 0, 4, 9 and 13.5 mm of axial displacement. Data collected at each point included forces on the specimen and medial and lateral coronoid processes as well as the angle of carpal joint extension. Results A linear mixed effects model relating load on the specimen and carpal joint extension angle had an R-squared value of 0....
Proceedings of the Nutrition Society, 2018
![Research paper thumbnail of Erratum to “Estimation of infection prevalence from correlated binomial samples” [Prev. Vet. Med. 64 (2004) 1–14]](https://attachments.academia-assets.com/85534804/thumbnails/1.jpg)
](Preventive Veterinary Medicine, 2004
The publisher regrets that in the above article Eq. (4) was printed incorrectly. It is now reprod... more The publisher regrets that in the above article Eq. (4) was printed incorrectly. It is now reproduced directly below. p ¼ X k j¼1p j expðm j Þ 1 þ expðm j Þ (4)
Clinical & Experimental Immunology, 2008
SUMMARY In vitro studies shows that recombinant tumour necrosis factor (TNF) α and β, and interfe... more SUMMARY In vitro studies shows that recombinant tumour necrosis factor (TNF) α and β, and interferon-gamma (IFN-γ) can enhance HIV replication, and peripheral blood mononuclear cells (PBMC) infected with HIV in vitro secrete high levels of the same cytokines. As T cells secrete all three mediators, the capacity of T cell activation signals to trigger cytokine production in PBMC from HIV-infected individuals was investigated as such patients may be immunocompromised. We demonstrate that asymptomatic seropositives in CDC group II/III as well as patients who have progressed to CDC group IV of the disease proliferate efficiently to anti-CD3 antibody, recombinant interleukin-2 (rIL-2), phytohaemagglutinin (PHA), PHA plus phorbol 12, 13 dibutyrate (PMA) but secrete significantly (P>0.05) higher amounts of TNF-α, TNF-β and IFN-γ compared with controls in response to the same stimulants. We also show a difference between group II/III and group IV patients with the latter secreting more T...
AIDS, 1997
Objectives: Hepatitis B virus (HBV) and HIV infections share risk factors; therefore, coinfection... more Objectives: Hepatitis B virus (HBV) and HIV infections share risk factors; therefore, coinfection is common. Interactions have been reported but controlled studies have been limited. Our objective was to study the effect of HIV infection on the natural history of chronic HBV infection and the reverse effect of the HBV carrier state on HIV infection. Design: Prospective observational cohort study. Setting: Open-access outpatient HIV/genitourinary medicine clinic at a Central London hospital. Patients: Total of 152 untreated homosexual male HBV carriers and 212 HBV surface antigen-negative controls (41.4 and 70.3% HIV-seropositive, respectively). Outcome measures: The rate of loss of serum HBV e antigen (HBeAg) and its reappearance in HIV-infected and HIV-uninfected HBV carriers; serum HBV DNA levels (measured by dot-blot hybridization assay), HBV DNA polymerase activity and liver transaminase activities; the progression of HIV infection to symptomatic disease or AIDS in HIV-infected compared with HBV-HIV coinfected patients. Results: In HIV-infected HBV carriers, serum HBV DNA polymerase activity was higher, alanine aminotransferase was lower and loss of serum HBeAg (mean followup, 2.8 years) occurred at a lower rate when compared with HIV-uninfected HBV carriers (estimated relative hazard, 0.39; 95% confidence interval, 0.161-0.942). Concomitant chronic HBV infection had no detectable effect on the rate of progression of HIV disease after correction for lead-time bias. Conclusion: This study strengthens the evidence for a significant effect of HIV infection on the natural history of chronic HBV infection, which by prolonging the period of infectivity could have an important impact on the epidemiology of HBV infection in regions, or patient groups, with high HIV seroprevalence. There was no evidence of an important effect of HBV carriage on HIV disease progression.
Bovine tuberculosis, a disease that affects cattle and badgers in Ireland, was studied via stocha... more Bovine tuberculosis, a disease that affects cattle and badgers in Ireland, was studied via stochastic epidemic modeling using incidence data from the Four Area Project (Griffin et al., 2005). The Four Area Project was a large scale field trial conducted in four diverse farming regions of Ireland over a five-year period (1997-2002) to evaluate the impact of badger culling on bovine tuberculosis incidence in cattle herds. Based on the comparison of several models, the model with no between-herd transmission and badger-to-herd transmission proportional to the total number of infected badgers culled was best supported by the data. Detailed model validation was conducted via model prediction, identifiability checks and sensitivity analysis. The results suggest that badger-to-cattle transmission is of more importance than between-herd transmission and that if there was no badger-to-herd transmission, levels of bovine tuberculosis in cattle herds in Ireland could decrease considerably.
Provided by the author(s) and University College Dublin Library in accordance with publisher poli... more Provided by the author(s) and University College Dublin Library in accordance with publisher policies. Please
Optical ray tracing-guided myopic laser in situ keratomileusis: 1-year clinical outcomes
Provided by the author(s) and University College Dublin Library in accordance with publisher poli... more Provided by the author(s) and University College Dublin Library in accordance with publisher policies. Please
The American review of respiratory disease, 1982
The thermodilution (TD) method of determining cardiac output (CO) is widely used in clinical prac... more The thermodilution (TD) method of determining cardiac output (CO) is widely used in clinical practice, but its reliability in this setting is not well understood and may be poor. This is especially true when dealing with unstable patients and using commercial TD devices. Numerous published reports have shown markedly variable results when comparing simultaneously the TD method and the Fick or dye-dilution methods in catheterization laboratories, intensive care units, or operating rooms. In order to assist clinicians in interpreting the reliability of the TD method in measuring CO, we analyzed all available published data (14 reports). The differing results in these reports were evaluated by standard statistical methods and by an extension of the influence function method of structural analysis developed to differentiate reproducibility and accuracy errors of each technique. Comparing the accuracy of the TD method with that of the Fick or the dye-dilution methods reveals that the 3 m...
The American review of respiratory disease, 1982
The thermodilution (TD) method of determining cardiac output (CO) is widely used in clinical prac... more The thermodilution (TD) method of determining cardiac output (CO) is widely used in clinical practice, but its reliability in this setting is not well understood and may be poor. This is especially true when dealing with unstable patients and using commercial TD devices. Numerous published reports have shown markedly variable results when comparing simultaneously the TD method and the Fick or dye-dilution methods in catheterization laboratories, intensive care units, or operating rooms. In order to assist clinicians in interpreting the reliability of the TD method in measuring CO, we analyzed all available published data (14 reports). The differing results in these reports were evaluated by standard statistical methods and by an extension of the influence function method of structural analysis developed to differentiate reproducibility and accuracy errors of each technique. Comparing the accuracy of the TD method with that of the Fick or the dye-dilution methods reveals that the 3 m...
Irish Journal of Medical Science, 1986
Epidemiology and Infection, 2007
SUMMARYAn observational study was carried out, using data collected from four areas in the Irish ... more SUMMARYAn observational study was carried out, using data collected from four areas in the Irish midlands, between 1989 and 2004, to critically evaluate the long-term effects of proactive badger culling and to provide insights into reactive badger culling tuberculosis (TB) prevalence in cattle. Confirmed cattle herd TB incidence is the outcome measure used throughout. Relative to reactive culling, proactive badger culling was associated with a decrease in incidence in each of the 16 years of observation, which encompassed periods of both intensive and less-intensive badger removal. By 2004, we observed a decrease of 22% [95% confidence interval (CI) 15–29, P<0·001] in the entire proactive and 37% (95% CI 25–47, P<0·001), in the inner proactive removal areas. The size of the decrease increased with time (P=0·055). There was a decrease (constant over time) of at least 14% (95% CI 76–97, P=0·013) in incidence in the inner compared to the outer control area (herds ⩽2 km, >2 km,...
The general form of the change-point problem is to determine the unknown location τ , based on an... more The general form of the change-point problem is to determine the unknown location τ , based on an ordered sequence of observations x 1 ,. .. , x n , such that the two groups of observations x 1 ,. .. , x τ and x τ +1 ,. .. , x n follow distinct models. We consider the two-phase regression model where x 1 ,. .. , x n follow a model β 01 + β 11 t, for some predictor variable t, and x τ +1 ,. .. , x n follow another model β 02 + β 12 t. There is an extensive statistical literature on this problem. An overview may be found in Carlstein et al. [1]. We use novel statistical methodology of hidden Markov models to determine the existence of a change-point. We use time series models, to estimate the position of the change-point. This extends the work of Kelly et al. [2]. In these models distributions other than the multivariate normal i.e. the multivariate power exponential distribution and the asymmetric multivariate Laplace distribution are considered. The variance may change with the location regression function and this is also incorporated in these models. The results are illustrated using gas exchange data from physiology as in Kelly et al. [3]. The scope for applications also includes drug compliance [4]; in veterinary epidemiology and biology change-point estimation has been used to find seasonal variation; Hall and Titterington [5] list applications from the engineering point of view in computer vision, computer graphics, signal processing, image processing, pattern recognition, geology etc.; Brown et al. [6] applied change-point methods in the field of economics.
A simulation study is implemented to study estimators of the covariance structure of a stationary... more A simulation study is implemented to study estimators of the covariance structure of a stationary Gaussian spatial process and a spatial process with t-distributed margins. The estimators compared are Gaussian restricted maximum likelihood (REML) and curve-fitting by ordinary least squares and by the nonparametric Shapiro-Botha approach. Processes with Matérn covariance functions are considered and the parameters estimated are the nugget, partial sill and practical range. Both parametric and nonparametric bootstrap distributions of the estimators are computed and compared to the true marginal distributions of the estimators. Gaussian REML is the estimator of choice for both Gaussian and t-distributed data and all choices of the Matérn covariance structure. However, accurate estimation of the Matérn shape parameter is critical to achieving a good fit while this does not affect the Shapiro-Botha estimator. The parametric bootstrap performed well for all estimators although it tended t...
Evidence that more people in some countries and fewer in others are dying because of the pandemic... more Evidence that more people in some countries and fewer in others are dying because of the pandemic, than is reflected by reported Covid-19 mortality rates, is derived from mortality data. Using publicly available databases, deaths attributed to Covid-19 in 2020 and all deaths for the years 2015-2020 were tabulated for 35 countries together with economic, health, demographic, and government response stringency index variables. Residual mortality rates (RMR) in 2020 were calculated as excess mortality minus reported mortality rates due to Covid-19 where excess deaths were observed deaths in 2020 minus the average for 2015-2019. Differences in RMR are differences not attributed to reported Covid-19. For about half the countries, RMR’s were negative and for half, positive. The absolute rates in some countries were double those in others. In a regression analysis, population density and proportion of female smokers were positively associated with both Covid-19 and excess mortality while t...
Veterinary and Comparative Orthopaedics and Traumatology, 2020
Objective The aim of this study was to measure the load on the lateral and medial aspects of the ... more Objective The aim of this study was to measure the load on the lateral and medial aspects of the proximal radio-ulnar joint during extension of the carpus. Study Design This was an ex vivo biomechanical study. Sample Population Twenty-two cadaveric Greyhound thoracic limbs were used. Methods Twenty-two paired thoracic limbs were used. The olecranon was attached to a custom jig with the foot resting on a stationary anvil. Load sensors were inserted into the proximal radio-ulnar joint, between the radial head and the lateral coronoid process, and between the radial head and the medial coronoid process. Specimens were tested under compression with measurements taken at 0, 4, 9 and 13.5 mm of axial displacement. Data collected at each point included forces on the specimen and medial and lateral coronoid processes as well as the angle of carpal joint extension. Results A linear mixed effects model relating load on the specimen and carpal joint extension angle had an R-squared value of 0....
Proceedings of the Nutrition Society, 2018
Preventive Veterinary Medicine, 2004
The publisher regrets that in the above article Eq. (4) was printed incorrectly. It is now reprod... more The publisher regrets that in the above article Eq. (4) was printed incorrectly. It is now reproduced directly below. p ¼ X k j¼1p j expðm j Þ 1 þ expðm j Þ (4)
Clinical & Experimental Immunology, 2008
SUMMARY In vitro studies shows that recombinant tumour necrosis factor (TNF) α and β, and interfe... more SUMMARY In vitro studies shows that recombinant tumour necrosis factor (TNF) α and β, and interferon-gamma (IFN-γ) can enhance HIV replication, and peripheral blood mononuclear cells (PBMC) infected with HIV in vitro secrete high levels of the same cytokines. As T cells secrete all three mediators, the capacity of T cell activation signals to trigger cytokine production in PBMC from HIV-infected individuals was investigated as such patients may be immunocompromised. We demonstrate that asymptomatic seropositives in CDC group II/III as well as patients who have progressed to CDC group IV of the disease proliferate efficiently to anti-CD3 antibody, recombinant interleukin-2 (rIL-2), phytohaemagglutinin (PHA), PHA plus phorbol 12, 13 dibutyrate (PMA) but secrete significantly (P>0.05) higher amounts of TNF-α, TNF-β and IFN-γ compared with controls in response to the same stimulants. We also show a difference between group II/III and group IV patients with the latter secreting more T...
AIDS, 1997
Objectives: Hepatitis B virus (HBV) and HIV infections share risk factors; therefore, coinfection... more Objectives: Hepatitis B virus (HBV) and HIV infections share risk factors; therefore, coinfection is common. Interactions have been reported but controlled studies have been limited. Our objective was to study the effect of HIV infection on the natural history of chronic HBV infection and the reverse effect of the HBV carrier state on HIV infection. Design: Prospective observational cohort study. Setting: Open-access outpatient HIV/genitourinary medicine clinic at a Central London hospital. Patients: Total of 152 untreated homosexual male HBV carriers and 212 HBV surface antigen-negative controls (41.4 and 70.3% HIV-seropositive, respectively). Outcome measures: The rate of loss of serum HBV e antigen (HBeAg) and its reappearance in HIV-infected and HIV-uninfected HBV carriers; serum HBV DNA levels (measured by dot-blot hybridization assay), HBV DNA polymerase activity and liver transaminase activities; the progression of HIV infection to symptomatic disease or AIDS in HIV-infected compared with HBV-HIV coinfected patients. Results: In HIV-infected HBV carriers, serum HBV DNA polymerase activity was higher, alanine aminotransferase was lower and loss of serum HBeAg (mean followup, 2.8 years) occurred at a lower rate when compared with HIV-uninfected HBV carriers (estimated relative hazard, 0.39; 95% confidence interval, 0.161-0.942). Concomitant chronic HBV infection had no detectable effect on the rate of progression of HIV disease after correction for lead-time bias. Conclusion: This study strengthens the evidence for a significant effect of HIV infection on the natural history of chronic HBV infection, which by prolonging the period of infectivity could have an important impact on the epidemiology of HBV infection in regions, or patient groups, with high HIV seroprevalence. There was no evidence of an important effect of HBV carriage on HIV disease progression.
Bovine tuberculosis, a disease that affects cattle and badgers in Ireland, was studied via stocha... more Bovine tuberculosis, a disease that affects cattle and badgers in Ireland, was studied via stochastic epidemic modeling using incidence data from the Four Area Project (Griffin et al., 2005). The Four Area Project was a large scale field trial conducted in four diverse farming regions of Ireland over a five-year period (1997-2002) to evaluate the impact of badger culling on bovine tuberculosis incidence in cattle herds. Based on the comparison of several models, the model with no between-herd transmission and badger-to-herd transmission proportional to the total number of infected badgers culled was best supported by the data. Detailed model validation was conducted via model prediction, identifiability checks and sensitivity analysis. The results suggest that badger-to-cattle transmission is of more importance than between-herd transmission and that if there was no badger-to-herd transmission, levels of bovine tuberculosis in cattle herds in Ireland could decrease considerably.
Provided by the author(s) and University College Dublin Library in accordance with publisher poli... more Provided by the author(s) and University College Dublin Library in accordance with publisher policies. Please
Optical ray tracing-guided myopic laser in situ keratomileusis: 1-year clinical outcomes
Provided by the author(s) and University College Dublin Library in accordance with publisher poli... more Provided by the author(s) and University College Dublin Library in accordance with publisher policies. Please