Lorenzo Cecconi | Università degli Studi di Firenze (University of Florence) (original) (raw)
Papers by Lorenzo Cecconi
Spinal Cord
Study design Multicenter prospective observational study of people with acute traumatic spinal co... more Study design Multicenter prospective observational study of people with acute traumatic spinal cord injury (TSCI) admitted to rehabilitation. Objectives To update epidemiological characteristics of a TSCI Italian population and verify the impact of patient characteristics at admission on two outcomes: functional gain (SCIM III) and discharge destination. Setting Thirty-one SCI centers for comprehensive rehabilitation in 13 Italian regions. Methods All consecutive individuals admitted with acute TSCI were enrolled from October 1, 2013 to September 30, 2014; data were recorded on rehabilitation admission and discharge. Functional gain and discharge destination were identified as outcome measures and statistically analyzed with patient characteristics at admission to identify early outcome predictors. Results Five hundred and ten individuals with TSCI met inclusion criteria; falls represented the most frequent etiology (45%). On admission, AIS A-B-C tetraplegia was reported in 35% of cases; AIS A-B-C paraplegia in 40%; AIS D paraplegia/tetraplegia in 25%. The majority were discharged home (72%). The mean (SD) SCIM gain was 38 ± 26 points. A predictive model was found for discharge setting: individuals with fall-related injuries, severe SCI (AIS A-B-C tetraplegia), tracheal cannula or indwelling catheter on admission, were less likely to be discharged home (OR 95% CI 0.15 [0.06, 0.35]). A model with a lower predictive power was found for SCIM gain, with lower score expected for females, older age, higher severity of SCI, a longer onset of injury admission interval (OAI), and mechanical ventilation on admission. Conclusions Prognostic factors in early rehabilitation are still hard to identify, making it difficult to correctly approach customized rehabilitation.
American journal of physical medicine & rehabilitation, Jan 23, 2018
to assess early post-stroke prognostic factors in patients admitted for post-acute phase rehabili... more to assess early post-stroke prognostic factors in patients admitted for post-acute phase rehabilitation. a one-year multicenter prospective project was conducted in four Italian regions on 352 patients who were hospitalized after a first stroke and were eligible for post-acute rehabilitation. Clinical data were collected in the Stroke or Acute Care Units (acute phase), then in Rehabilitation Units (post-acute phase) and, subsequently, after a 6-month post-stroke period (follow-up). Clinical outcome measures were represented using the Barthel Index (BI) and the modified Rankin Scale (mRS). Univariate and multivariate analyses were performed to identify the most important prognostic index. mRS score, minor neurologic impairment and early out-of-bed mobilization (within 2 days after the stroke) proved to be important factors related to a better recovery according to BI (power of prediction = 37%). Similarly, age, pre-morbid mRS score and early out-of-bed mobilization were seen to be si...
PloS one, 2018
The outcome of stroke patients is complex and multidimensional. We evaluated the impact of acute-... more The outcome of stroke patients is complex and multidimensional. We evaluated the impact of acute-phase variables, including clinical state, complications, resource use and interventions, on 6-month survival after first-ever stroke, taking into account baseline conditions exerting a possible effect on outcome. As part of a National Research Program, we performed a prospective observational study of acute stroke patients in four Italian Regions. Consecutive patients admitted for a period of 3 months to the emergency rooms of participating hospitals were included. A total of 1030 patients were enrolled (median age 76.0 years, 52.1% males). At 6 months, 816 (79.2%) were alive, and 164 (15.9%) deceased. Survival status at the 6-month follow-up was missing for 50 (4.9%). Neurological state in the acute phase was significantly worse in patients deceased at 6 months, who showed also higher frequency of acute-phase complications. Cox regression analysis adjusted for demographics, pre-stroke ...
American Journal of Otolaryngology, 2017
Adenoid cystic carcinoma (ACC) is a uncommon salivary malignant tumor. Our aim was to review our ... more Adenoid cystic carcinoma (ACC) is a uncommon salivary malignant tumor. Our aim was to review our experience with parotid ACC, to identify clinical-pathological parameters predictive for outcome. Materials and methods: We retrospectively reviewed 228 patients affected by parotid gland carcinomas surgically treated at our Institution. Forty-four ACC were included in this study. Multivariate analysis risk models were built to predict recurrence free probability (RFP), distant recurrence free probability (DRFP), overall survival (OS) and disease free survival (DFS). Results: Twenty-one patients (47.7%) died from ACC and 2.3% for other causes. The 41% presented local-regional recurrence, with a regional-RFP rate of 93%, and the 34% reported distant metastases (DM). The five and ten-year OS rates were 74% and 50%, respectively. Conclusions: Recurrences were mainly influenced by the presence of perineural invasion and nerve paralysis, whilst female gender and age b 50 were predictors for good prognosis.
Statistical Methods in Medical Research, 2016
Preferential sampling refers to any situation in which the spatial process and the sampling locat... more Preferential sampling refers to any situation in which the spatial process and the sampling locations are not stochastically independent. In this paper, we present two examples of geostatistical analysis in which the usual assumption of stochastic independence between the point process and the measurement process is violated. To account for preferential sampling, we specify a flexible and general Bayesian geostatistical model that includes a shared spatial random component. We apply the proposed model to two different case studies that allow us to highlight three different modeling and inferential aspects of geostatistical modeling under preferential sampling: (1) continuous or finite spatial sampling frame; (2) underlying causal model and relevant covariates; and (3) inferential goals related to mean prediction surface or prediction uncertainty.
Breast Cancer, 2016
Reconstruction options following nipple-sparing mastectomy (NSM) are diverse and not yet investig... more Reconstruction options following nipple-sparing mastectomy (NSM) are diverse and not yet investigated with level IA evidence. The analysis of surgical and oncological outcomes of NSM from the Italian National Registry shows its safety and wide acceptance both for prophylactic and therapeutic cases. A further in-depth analysis of the reconstructive approaches with their trend over time and their failures is the aim of this study. Data extraction from the National Database was performed restricting cases to the 2009-2014 period. Different reconstruction procedures were analyzed in terms of their distribution over time and with respect to specific indications. A 1-year minimum follow-up was conducted to assess reconstructive unsuccessful events. Univariate and multivariate analyses were performed to investigate the causes of both prosthetic and autologous failures. 913 patients, for a total of 1006 procedures, are included in the analysis. A prosthetic only reconstruction is accomplished in 92.2 % of cases, while pure autologous tissues are employed in 4.2 % and a hybrid (prosthetic plus autologous) in 3.6 %. Direct-to-implant (DTI) reaches 48.7 % of all reconstructions in the year 2014. Prophylactic NSMs have a DTI reconstruction in 35.6 % of cases and an autologous tissue flap in 12.9 % of cases. Failures are 2.7 % overall: 0 % in pure autologous flaps and 9.1 % in hybrid cases. Significant risk factors for failures are diabetes and the previous radiation therapy on the operated breast. Reconstruction following NSM is mostly prosthetic in Italy, with DTI gaining large acceptance over time. Failures are low and occurring in diabetic and irradiated patients at the multivariate analysis.
Critical Reviews in Oncology/Hematology, 2016
Background: Multi-step cancerogenesis guides laryngeal cancer onset and it includes a wide variet... more Background: Multi-step cancerogenesis guides laryngeal cancer onset and it includes a wide variety of pre-cancerous lesions that are macroscopically challenging to identify and distinguish from initial cancerous foci. Since the treatment of laryngeal cancer and its precursor lesions has a great impact on important laryngeal basic functions, early detection and preoperative assessment are important for a curative and function-preserving therapy. Nowadays, despite the high number of more advanced diagnostic techniques and methods, unfortunately, it is not uncommon for different clinicians to use different nomenclature or to identify different stage for the same laryngeal lesion. From these observations, it is obvious that an instrument offering the possibility to detect precancerous lesions, early cancerous lesions, and satellite foci or second primaries would be the key to improving management and outcome in laryngeal patients. Object. Different modalities of diagnostic techniques of laryngeal lesions exist. Rather than difference between benign and obvious malignant diseases, more difficult is to detect the presence of precancerous epithelial alterations. Not all tests achieve the same diagnostic accuracy, hence this meta-analysis of literature aimed to synthesize the validity of each single diagnostic technique in identifying and staging laryngeal disease. Methods: A systematic review of literature was led searching for articles mentioning the following terms including their various combinations to maximize the yield: larynx, laryngeal precancerous lesions, laryngeal cancer, white light (WL) endoscopy, stroboscopy, contact endoscopy (CE), autofluorescence (AF), ultrasound (US), narrow band imaging (NBI), computed axial tomography (CAT), magnetic resonance imaging (MRI), positron emission tomography (PET), CAT/PET. Then, a quantitative analysis was carried on for paper published after 2005 onward, reporting a minumun series of 10 patients each study, declaring sensitivity and specificity of each diagnostic system. Results: The search identified 7215 publications, of which 3616 published after 2005, with a final results of a total of 214 articles stratified and included by our selection criteria. 42 out of 214 articles were selected for quantitative synthesis. 25 out of 41 studies had a quality score of ≥ 6 (good), 16 presented a score between 4 and 5 (fair). While objections can be raised about the pooling of different diagnostic procedures under the same group and the high level of heterogeneity in the meta-analyses, the inclusion of over 4400 laryngeal lesions makes the results fairly robust. Conclusions: A comprehensive overview of the most recent advances in laryngeal imaging technology combined with all of the information needed to interpret findings and successfully manage patients with voice disorders can be found herein. With these data, clinicians can riskstratify patients and select proper examination modalities in order to provide appropriate care. Moreover, study limitations, together with possible clinical and research implications have been counted, as well.
Geospatial Health, 2016
In this paper the focus is on environmental statistics, with the aim of estimating the concentrat... more In this paper the focus is on environmental statistics, with the aim of estimating the concentration surface and related uncertainty of an air pollutant. We used air quality data recorded by a network of monitoring stations within a Bayesian framework to overcome difficulties in accounting for prediction uncertainty and to integrate information provided by deterministic models based on emissions meteorology and chemico-physical characteristics of the atmosphere. Several authors have proposed such integration, but all the proposed approaches rely on representativeness and completeness of existing air pollution monitoring networks. We considered the situation in which the spatial process of interest and the sampling locations are not independent. This is known in the literature as the preferential sampling problem, which if ignored in the analysis, can bias geostatistical inferences. We developed a Bayesian geostatistical model to account for preferential sampling with the main intere...
Geospatial Health, 2016
Incidence distribution of cutaneous melanoma depends on phenotypic characteristics of population ... more Incidence distribution of cutaneous melanoma depends on phenotypic characteristics of population and geographic location. In Italy, in the period 1999-2003 Friuli Venezia Giulia (FVG) region had the second highest incidence rates for males and the third for females. We analysed melanoma and lip cancer incidence data of the FVG cancer registry for the period 1995-2005. We used Bayesian hierarchical spatial models to describe the spatial pattern by gender. We decomposed the geographical distribution of the risk in two parts: a component linked to chronic exposure and a component related to intermittent exposure. In order to model the chronic component we considered the geographical distribution of incidence cases of lip cancer, for which chronic occupational solar radiation exposure is a documented risk factor. We also analysed the distribution by site and we calculated standardised rates for body surface area. This study documents a significant gradient in the incidence of cutaneous ...
Geospatial Health, 2016
In parasitological surveillance of livestock, prevalence surveys are conducted on a sample of far... more In parasitological surveillance of livestock, prevalence surveys are conducted on a sample of farms using several sampling designs. For example, opportunistic surveys or informative sampling designs are very common. Preferential sampling refers to any situation in which the spatial process and the sampling locations are not independent. Most examples of preferential sampling in the spatial statistics literature are in environmental statistics with focus on pollutant monitors, and it has been shown that, if preferential sampling is present and is not accounted for in the statistical modelling and data analysis, statistical inference can be misleading. In this paper, working in the context of veterinary parasitology, we propose and use geostatistical models to predict the continuous and spatially-varying risk of a parasite infection. Specifically, breaking with the common practice in veterinary parasitological surveillance to ignore preferential sampling even though informative or opp...
Plastic and Reconstructive Surgery - Global Open, 2015
A n implant-based breast reconstruction (IBBR) is by far the preferred way of restoring a female ... more A n implant-based breast reconstruction (IBBR) is by far the preferred way of restoring a female breast after mastectomy and a 2-stage breast reconstruction, by means of a tissue expander, accounts for approximately 70% of all reconstructions according to the American Society of Plastic Surgeons statistics. 1 Nonetheless, the opportunity of
Geospatial health, Jan 18, 2016
In this paper the focus is on environmental statistics, with the aim of estimating the concentrat... more In this paper the focus is on environmental statistics, with the aim of estimating the concentration surface and related uncertainty of an air pollutant. We used air quality data recorded by a network of monitoring stations within a Bayesian framework to overcome difficulties in accounting for prediction uncertainty and to integrate information provided by deterministic models based on emissions meteorology and chemico-physical characteristics of the atmosphere. Several authors have proposed such integration, but all the proposed approaches rely on representativeness and completeness of existing air pollution monitoring networks. We considered the situation in which the spatial process of interest and the sampling locations are not independent. This is known in the literature as the preferential sampling problem, which if ignored in the analysis, can bias geostatistical inferences. We developed a Bayesian geostatistical model to account for preferential sampling with the main intere...
Abstract We consider the classic problem of estimating the total number T of species in a populat... more Abstract We consider the classic problem of estimating the total number T of species in a population, from repeated counts in a simple random sample. We first show that one of the most widely used estimators can be obtained via a Bayesian method from a Dirichlet prior, ...
Arxiv preprint arXiv:1107.1532, Jan 1, 2011
Spinal Cord
Study design Multicenter prospective observational study of people with acute traumatic spinal co... more Study design Multicenter prospective observational study of people with acute traumatic spinal cord injury (TSCI) admitted to rehabilitation. Objectives To update epidemiological characteristics of a TSCI Italian population and verify the impact of patient characteristics at admission on two outcomes: functional gain (SCIM III) and discharge destination. Setting Thirty-one SCI centers for comprehensive rehabilitation in 13 Italian regions. Methods All consecutive individuals admitted with acute TSCI were enrolled from October 1, 2013 to September 30, 2014; data were recorded on rehabilitation admission and discharge. Functional gain and discharge destination were identified as outcome measures and statistically analyzed with patient characteristics at admission to identify early outcome predictors. Results Five hundred and ten individuals with TSCI met inclusion criteria; falls represented the most frequent etiology (45%). On admission, AIS A-B-C tetraplegia was reported in 35% of cases; AIS A-B-C paraplegia in 40%; AIS D paraplegia/tetraplegia in 25%. The majority were discharged home (72%). The mean (SD) SCIM gain was 38 ± 26 points. A predictive model was found for discharge setting: individuals with fall-related injuries, severe SCI (AIS A-B-C tetraplegia), tracheal cannula or indwelling catheter on admission, were less likely to be discharged home (OR 95% CI 0.15 [0.06, 0.35]). A model with a lower predictive power was found for SCIM gain, with lower score expected for females, older age, higher severity of SCI, a longer onset of injury admission interval (OAI), and mechanical ventilation on admission. Conclusions Prognostic factors in early rehabilitation are still hard to identify, making it difficult to correctly approach customized rehabilitation.
American journal of physical medicine & rehabilitation, Jan 23, 2018
to assess early post-stroke prognostic factors in patients admitted for post-acute phase rehabili... more to assess early post-stroke prognostic factors in patients admitted for post-acute phase rehabilitation. a one-year multicenter prospective project was conducted in four Italian regions on 352 patients who were hospitalized after a first stroke and were eligible for post-acute rehabilitation. Clinical data were collected in the Stroke or Acute Care Units (acute phase), then in Rehabilitation Units (post-acute phase) and, subsequently, after a 6-month post-stroke period (follow-up). Clinical outcome measures were represented using the Barthel Index (BI) and the modified Rankin Scale (mRS). Univariate and multivariate analyses were performed to identify the most important prognostic index. mRS score, minor neurologic impairment and early out-of-bed mobilization (within 2 days after the stroke) proved to be important factors related to a better recovery according to BI (power of prediction = 37%). Similarly, age, pre-morbid mRS score and early out-of-bed mobilization were seen to be si...
PloS one, 2018
The outcome of stroke patients is complex and multidimensional. We evaluated the impact of acute-... more The outcome of stroke patients is complex and multidimensional. We evaluated the impact of acute-phase variables, including clinical state, complications, resource use and interventions, on 6-month survival after first-ever stroke, taking into account baseline conditions exerting a possible effect on outcome. As part of a National Research Program, we performed a prospective observational study of acute stroke patients in four Italian Regions. Consecutive patients admitted for a period of 3 months to the emergency rooms of participating hospitals were included. A total of 1030 patients were enrolled (median age 76.0 years, 52.1% males). At 6 months, 816 (79.2%) were alive, and 164 (15.9%) deceased. Survival status at the 6-month follow-up was missing for 50 (4.9%). Neurological state in the acute phase was significantly worse in patients deceased at 6 months, who showed also higher frequency of acute-phase complications. Cox regression analysis adjusted for demographics, pre-stroke ...
American Journal of Otolaryngology, 2017
Adenoid cystic carcinoma (ACC) is a uncommon salivary malignant tumor. Our aim was to review our ... more Adenoid cystic carcinoma (ACC) is a uncommon salivary malignant tumor. Our aim was to review our experience with parotid ACC, to identify clinical-pathological parameters predictive for outcome. Materials and methods: We retrospectively reviewed 228 patients affected by parotid gland carcinomas surgically treated at our Institution. Forty-four ACC were included in this study. Multivariate analysis risk models were built to predict recurrence free probability (RFP), distant recurrence free probability (DRFP), overall survival (OS) and disease free survival (DFS). Results: Twenty-one patients (47.7%) died from ACC and 2.3% for other causes. The 41% presented local-regional recurrence, with a regional-RFP rate of 93%, and the 34% reported distant metastases (DM). The five and ten-year OS rates were 74% and 50%, respectively. Conclusions: Recurrences were mainly influenced by the presence of perineural invasion and nerve paralysis, whilst female gender and age b 50 were predictors for good prognosis.
Statistical Methods in Medical Research, 2016
Preferential sampling refers to any situation in which the spatial process and the sampling locat... more Preferential sampling refers to any situation in which the spatial process and the sampling locations are not stochastically independent. In this paper, we present two examples of geostatistical analysis in which the usual assumption of stochastic independence between the point process and the measurement process is violated. To account for preferential sampling, we specify a flexible and general Bayesian geostatistical model that includes a shared spatial random component. We apply the proposed model to two different case studies that allow us to highlight three different modeling and inferential aspects of geostatistical modeling under preferential sampling: (1) continuous or finite spatial sampling frame; (2) underlying causal model and relevant covariates; and (3) inferential goals related to mean prediction surface or prediction uncertainty.
Breast Cancer, 2016
Reconstruction options following nipple-sparing mastectomy (NSM) are diverse and not yet investig... more Reconstruction options following nipple-sparing mastectomy (NSM) are diverse and not yet investigated with level IA evidence. The analysis of surgical and oncological outcomes of NSM from the Italian National Registry shows its safety and wide acceptance both for prophylactic and therapeutic cases. A further in-depth analysis of the reconstructive approaches with their trend over time and their failures is the aim of this study. Data extraction from the National Database was performed restricting cases to the 2009-2014 period. Different reconstruction procedures were analyzed in terms of their distribution over time and with respect to specific indications. A 1-year minimum follow-up was conducted to assess reconstructive unsuccessful events. Univariate and multivariate analyses were performed to investigate the causes of both prosthetic and autologous failures. 913 patients, for a total of 1006 procedures, are included in the analysis. A prosthetic only reconstruction is accomplished in 92.2 % of cases, while pure autologous tissues are employed in 4.2 % and a hybrid (prosthetic plus autologous) in 3.6 %. Direct-to-implant (DTI) reaches 48.7 % of all reconstructions in the year 2014. Prophylactic NSMs have a DTI reconstruction in 35.6 % of cases and an autologous tissue flap in 12.9 % of cases. Failures are 2.7 % overall: 0 % in pure autologous flaps and 9.1 % in hybrid cases. Significant risk factors for failures are diabetes and the previous radiation therapy on the operated breast. Reconstruction following NSM is mostly prosthetic in Italy, with DTI gaining large acceptance over time. Failures are low and occurring in diabetic and irradiated patients at the multivariate analysis.
Critical Reviews in Oncology/Hematology, 2016
Background: Multi-step cancerogenesis guides laryngeal cancer onset and it includes a wide variet... more Background: Multi-step cancerogenesis guides laryngeal cancer onset and it includes a wide variety of pre-cancerous lesions that are macroscopically challenging to identify and distinguish from initial cancerous foci. Since the treatment of laryngeal cancer and its precursor lesions has a great impact on important laryngeal basic functions, early detection and preoperative assessment are important for a curative and function-preserving therapy. Nowadays, despite the high number of more advanced diagnostic techniques and methods, unfortunately, it is not uncommon for different clinicians to use different nomenclature or to identify different stage for the same laryngeal lesion. From these observations, it is obvious that an instrument offering the possibility to detect precancerous lesions, early cancerous lesions, and satellite foci or second primaries would be the key to improving management and outcome in laryngeal patients. Object. Different modalities of diagnostic techniques of laryngeal lesions exist. Rather than difference between benign and obvious malignant diseases, more difficult is to detect the presence of precancerous epithelial alterations. Not all tests achieve the same diagnostic accuracy, hence this meta-analysis of literature aimed to synthesize the validity of each single diagnostic technique in identifying and staging laryngeal disease. Methods: A systematic review of literature was led searching for articles mentioning the following terms including their various combinations to maximize the yield: larynx, laryngeal precancerous lesions, laryngeal cancer, white light (WL) endoscopy, stroboscopy, contact endoscopy (CE), autofluorescence (AF), ultrasound (US), narrow band imaging (NBI), computed axial tomography (CAT), magnetic resonance imaging (MRI), positron emission tomography (PET), CAT/PET. Then, a quantitative analysis was carried on for paper published after 2005 onward, reporting a minumun series of 10 patients each study, declaring sensitivity and specificity of each diagnostic system. Results: The search identified 7215 publications, of which 3616 published after 2005, with a final results of a total of 214 articles stratified and included by our selection criteria. 42 out of 214 articles were selected for quantitative synthesis. 25 out of 41 studies had a quality score of ≥ 6 (good), 16 presented a score between 4 and 5 (fair). While objections can be raised about the pooling of different diagnostic procedures under the same group and the high level of heterogeneity in the meta-analyses, the inclusion of over 4400 laryngeal lesions makes the results fairly robust. Conclusions: A comprehensive overview of the most recent advances in laryngeal imaging technology combined with all of the information needed to interpret findings and successfully manage patients with voice disorders can be found herein. With these data, clinicians can riskstratify patients and select proper examination modalities in order to provide appropriate care. Moreover, study limitations, together with possible clinical and research implications have been counted, as well.
Geospatial Health, 2016
In this paper the focus is on environmental statistics, with the aim of estimating the concentrat... more In this paper the focus is on environmental statistics, with the aim of estimating the concentration surface and related uncertainty of an air pollutant. We used air quality data recorded by a network of monitoring stations within a Bayesian framework to overcome difficulties in accounting for prediction uncertainty and to integrate information provided by deterministic models based on emissions meteorology and chemico-physical characteristics of the atmosphere. Several authors have proposed such integration, but all the proposed approaches rely on representativeness and completeness of existing air pollution monitoring networks. We considered the situation in which the spatial process of interest and the sampling locations are not independent. This is known in the literature as the preferential sampling problem, which if ignored in the analysis, can bias geostatistical inferences. We developed a Bayesian geostatistical model to account for preferential sampling with the main intere...
Geospatial Health, 2016
Incidence distribution of cutaneous melanoma depends on phenotypic characteristics of population ... more Incidence distribution of cutaneous melanoma depends on phenotypic characteristics of population and geographic location. In Italy, in the period 1999-2003 Friuli Venezia Giulia (FVG) region had the second highest incidence rates for males and the third for females. We analysed melanoma and lip cancer incidence data of the FVG cancer registry for the period 1995-2005. We used Bayesian hierarchical spatial models to describe the spatial pattern by gender. We decomposed the geographical distribution of the risk in two parts: a component linked to chronic exposure and a component related to intermittent exposure. In order to model the chronic component we considered the geographical distribution of incidence cases of lip cancer, for which chronic occupational solar radiation exposure is a documented risk factor. We also analysed the distribution by site and we calculated standardised rates for body surface area. This study documents a significant gradient in the incidence of cutaneous ...
Geospatial Health, 2016
In parasitological surveillance of livestock, prevalence surveys are conducted on a sample of far... more In parasitological surveillance of livestock, prevalence surveys are conducted on a sample of farms using several sampling designs. For example, opportunistic surveys or informative sampling designs are very common. Preferential sampling refers to any situation in which the spatial process and the sampling locations are not independent. Most examples of preferential sampling in the spatial statistics literature are in environmental statistics with focus on pollutant monitors, and it has been shown that, if preferential sampling is present and is not accounted for in the statistical modelling and data analysis, statistical inference can be misleading. In this paper, working in the context of veterinary parasitology, we propose and use geostatistical models to predict the continuous and spatially-varying risk of a parasite infection. Specifically, breaking with the common practice in veterinary parasitological surveillance to ignore preferential sampling even though informative or opp...
Plastic and Reconstructive Surgery - Global Open, 2015
A n implant-based breast reconstruction (IBBR) is by far the preferred way of restoring a female ... more A n implant-based breast reconstruction (IBBR) is by far the preferred way of restoring a female breast after mastectomy and a 2-stage breast reconstruction, by means of a tissue expander, accounts for approximately 70% of all reconstructions according to the American Society of Plastic Surgeons statistics. 1 Nonetheless, the opportunity of
Geospatial health, Jan 18, 2016
In this paper the focus is on environmental statistics, with the aim of estimating the concentrat... more In this paper the focus is on environmental statistics, with the aim of estimating the concentration surface and related uncertainty of an air pollutant. We used air quality data recorded by a network of monitoring stations within a Bayesian framework to overcome difficulties in accounting for prediction uncertainty and to integrate information provided by deterministic models based on emissions meteorology and chemico-physical characteristics of the atmosphere. Several authors have proposed such integration, but all the proposed approaches rely on representativeness and completeness of existing air pollution monitoring networks. We considered the situation in which the spatial process of interest and the sampling locations are not independent. This is known in the literature as the preferential sampling problem, which if ignored in the analysis, can bias geostatistical inferences. We developed a Bayesian geostatistical model to account for preferential sampling with the main intere...
Abstract We consider the classic problem of estimating the total number T of species in a populat... more Abstract We consider the classic problem of estimating the total number T of species in a population, from repeated counts in a simple random sample. We first show that one of the most widely used estimators can be obtained via a Bayesian method from a Dirichlet prior, ...
Arxiv preprint arXiv:1107.1532, Jan 1, 2011