ADBD - Anàlisi de Dades Complexes per a les Decisions Empresarials
http://hdl.handle.net/2117/79665
Wed, 17 Jul 2019 00:35:00 GMT2019-07-17T00:35:00ZDifferences in eye health, access to eye care specialists and use of lenses among immigrant and native-Born Workers in Spain
http://hdl.handle.net/2117/134344
Differences in eye health, access to eye care specialists and use of lenses among immigrant and native-Born Workers in Spain
Seguí Crespo, Mari Mar; Cantó Sancho, Natalia; Reid, Alison; Martínez Martínez, José Miguel; Ronda Pérez, Elena
Latin American immigrants make up 49% of the total immigrant population in Spain, yet little is known about their eye health. The aim of this study is to determine if there are differences in self-perceived eye health, access to eye care specialists, and use of lenses between a sample of Latin American immigrant workers from Colombia and Ecuador, and native-born workers in Spain. We used data from the PELFI cohort (Project for Longitudinal Studies of Immigrant Families). The sample consisted of 179 immigrant workers born in Colombia or Ecuador, and 83 Spanish-born workers. The outcome variables were self-perceived eye health, access to eye specialists, and use of lenses. A descriptive analysis of the sample was carried out, and the prevalence of the three outcome variables in immigrants and natives was calculated and adjusted for explanatory variables. Random effects logistic regression models examined eye health outcomes by workers’ country of birth. Immigrants are less likely to report poor self-perceived eye health than native-born (ORc 0.46; CI 95%, 0.22–0.96). Furthermore, they have less access to specialists (ORc 2.61; CI 95%, 1.32–5.15) and a higher probability of needing lenses but not having them (ORc 14.14; CI 95%, 1.77–112.69). This latter variable remained statistically significant after adjusting for covariates (ORa 34.05; CI 95%, 1.59–729.04). Latin American immigrants may not value the use of lenses, despite eye care specialists indicating that they need them. Eye health education is required to recognize the importance of using lenses according to their visual needs
Wed, 12 Jun 2019 12:11:30 GMThttp://hdl.handle.net/2117/1343442019-06-12T12:11:30ZSeguí Crespo, Mari MarCantó Sancho, NataliaReid, AlisonMartínez Martínez, José MiguelRonda Pérez, ElenaLatin American immigrants make up 49% of the total immigrant population in Spain, yet little is known about their eye health. The aim of this study is to determine if there are differences in self-perceived eye health, access to eye care specialists, and use of lenses between a sample of Latin American immigrant workers from Colombia and Ecuador, and native-born workers in Spain. We used data from the PELFI cohort (Project for Longitudinal Studies of Immigrant Families). The sample consisted of 179 immigrant workers born in Colombia or Ecuador, and 83 Spanish-born workers. The outcome variables were self-perceived eye health, access to eye specialists, and use of lenses. A descriptive analysis of the sample was carried out, and the prevalence of the three outcome variables in immigrants and natives was calculated and adjusted for explanatory variables. Random effects logistic regression models examined eye health outcomes by workers’ country of birth. Immigrants are less likely to report poor self-perceived eye health than native-born (ORc 0.46; CI 95%, 0.22–0.96). Furthermore, they have less access to specialists (ORc 2.61; CI 95%, 1.32–5.15) and a higher probability of needing lenses but not having them (ORc 14.14; CI 95%, 1.77–112.69). This latter variable remained statistically significant after adjusting for covariates (ORa 34.05; CI 95%, 1.59–729.04). Latin American immigrants may not value the use of lenses, despite eye care specialists indicating that they need them. Eye health education is required to recognize the importance of using lenses according to their visual needsBayesian model selection for the study of Hardy-Weinberg proportions and homogeneity of gender allele frequencies
http://hdl.handle.net/2117/134111
Bayesian model selection for the study of Hardy-Weinberg proportions and homogeneity of gender allele frequencies
Puig Oriol, Xavier; Ginebra Molins, Josep; Graffelman, Jan
Standard statistical tests for Hardy-Weinberg equilibrium assume the equality of allele frequencies in the sexes, whereas tests for the equality of allele frequencies in the sexes assume Hardy–Weinberg equilibrium. This produces a circularity in the testing of genetic variants, which has recently been resolved with new frequentist likelihood and exact procedures. In this paper, we tackle the same problem by posing it as a Bayesian model comparison problem. We formulate an exhaustive
set of ten alternative scenarios for biallelic genetic variants. Using Dirichlet and Beta priors for genotype and allele frequencies, we derive marginal likelihoods for all scenarios, and select the most likely scenario using the posterior probabilities that each of these scenarios is the one in place. Different from the usual frequentist testing approach, the Bayesian approach allows one to compare any number of models, and not just two at a time, and the models compared do not have to be nested. We illustrate our Bayesian approach with genetic data from the 1,000 genomes project and through a simulation study.
Thu, 06 Jun 2019 11:19:54 GMThttp://hdl.handle.net/2117/1341112019-06-06T11:19:54ZPuig Oriol, XavierGinebra Molins, JosepGraffelman, JanStandard statistical tests for Hardy-Weinberg equilibrium assume the equality of allele frequencies in the sexes, whereas tests for the equality of allele frequencies in the sexes assume Hardy–Weinberg equilibrium. This produces a circularity in the testing of genetic variants, which has recently been resolved with new frequentist likelihood and exact procedures. In this paper, we tackle the same problem by posing it as a Bayesian model comparison problem. We formulate an exhaustive
set of ten alternative scenarios for biallelic genetic variants. Using Dirichlet and Beta priors for genotype and allele frequencies, we derive marginal likelihoods for all scenarios, and select the most likely scenario using the posterior probabilities that each of these scenarios is the one in place. Different from the usual frequentist testing approach, the Bayesian approach allows one to compare any number of models, and not just two at a time, and the models compared do not have to be nested. We illustrate our Bayesian approach with genetic data from the 1,000 genomes project and through a simulation study.Transfer function and time series outlier analysis: modelling Soil salinity in loamy sand soil by including the influences of irrigation management and soil temperature
http://hdl.handle.net/2117/130637
Transfer function and time series outlier analysis: modelling Soil salinity in loamy sand soil by including the influences of irrigation management and soil temperature
Aljoumani, Basem; Sánchez Espigares, Josep Anton; Cañameras Riba, Núria; Wessdek, Gerd; Josa March, Ramon
In variable interval irrigation, simply including soil salinity data in the soil salinity model is not valid for making predictions, because changes in irrigation frequency must also be taken into account. This study on variable interval irrigation used capacitance soil sensors simultaneously to obtain hourly measurements of bulk electrical conductivity (sb), soil temperature (t) and soil water content (¿). Observations of sb were converted so that the electrical conductivity of the pore water (sp) could be estimated as an indicator of soil salinity. Values of ¿, t and sp were used to test a mathematical model for studying how sp cross-correlates with t and ¿ to predict soil salinity at a given depth. These predictions were based on measurements of sp, t, and ¿ at a shallow depth. As a result, prediction at shallow depth was successful after integrating intervention analysis and outlier detection into the seasonal autoregressive integrated moving average (ARIMA) model. We then used the (multiple-input/one-output) transfer function models to logically predict soil salinity at the depths of interest. The model could also correctly determine the effect of the irrigation event on soil salinity
Wed, 20 Mar 2019 07:49:21 GMThttp://hdl.handle.net/2117/1306372019-03-20T07:49:21ZAljoumani, BasemSánchez Espigares, Josep AntonCañameras Riba, NúriaWessdek, GerdJosa March, RamonIn variable interval irrigation, simply including soil salinity data in the soil salinity model is not valid for making predictions, because changes in irrigation frequency must also be taken into account. This study on variable interval irrigation used capacitance soil sensors simultaneously to obtain hourly measurements of bulk electrical conductivity (sb), soil temperature (t) and soil water content (¿). Observations of sb were converted so that the electrical conductivity of the pore water (sp) could be estimated as an indicator of soil salinity. Values of ¿, t and sp were used to test a mathematical model for studying how sp cross-correlates with t and ¿ to predict soil salinity at a given depth. These predictions were based on measurements of sp, t, and ¿ at a shallow depth. As a result, prediction at shallow depth was successful after integrating intervention analysis and outlier detection into the seasonal autoregressive integrated moving average (ARIMA) model. We then used the (multiple-input/one-output) transfer function models to logically predict soil salinity at the depths of interest. The model could also correctly determine the effect of the irrigation event on soil salinityWhich runs to skip in two-level factorial designs when not all can be performed
http://hdl.handle.net/2117/130379
Which runs to skip in two-level factorial designs when not all can be performed
Xampeny Solani, Rafael; Grima Cintas, Pedro; Tort-Martorell Llabrés, Xavier
When a two-level factorial design allows estimating contrasts that can be considered negligible from scratch, it is possible to omit some runs and later estimate their values by equating to zero the expressions of some of that contrasts. This article presents the combinations of runs to be omitted in 8 and 16 runs two-level factorial designs so that the responses can be estimated in such a way as to produce the least possible impact on the desired properties of the estimated contrasts: low and equal variance and the smallest possible correlation among them.
Wed, 13 Mar 2019 12:22:31 GMThttp://hdl.handle.net/2117/1303792019-03-13T12:22:31ZXampeny Solani, RafaelGrima Cintas, PedroTort-Martorell Llabrés, XavierWhen a two-level factorial design allows estimating contrasts that can be considered negligible from scratch, it is possible to omit some runs and later estimate their values by equating to zero the expressions of some of that contrasts. This article presents the combinations of runs to be omitted in 8 and 16 runs two-level factorial designs so that the responses can be estimated in such a way as to produce the least possible impact on the desired properties of the estimated contrasts: low and equal variance and the smallest possible correlation among them.Selecting significant effects in factorial designs: Lenth's method versus using negligible interactions
http://hdl.handle.net/2117/130367
Selecting significant effects in factorial designs: Lenth's method versus using negligible interactions
Xampeny Solani, Rafael; Grima Cintas, Pedro; Tort-Martorell Llabrés, Xavier
Among the many analytical techniques that have been published to analyze the significance of the effects in the absence of replications, two have emerged as the most widely used in text books as well as statistical software packages: The Lenth's method and the estimation of the variance of the effects from the values of those considered negligible. This article shows that neither is better than the other in all cases, and by analyzing the results obtained in a wide variety of situations it provides guidelines on when it is preferable to use one or the other technique
Wed, 13 Mar 2019 11:43:26 GMThttp://hdl.handle.net/2117/1303672019-03-13T11:43:26ZXampeny Solani, RafaelGrima Cintas, PedroTort-Martorell Llabrés, XavierAmong the many analytical techniques that have been published to analyze the significance of the effects in the absence of replications, two have emerged as the most widely used in text books as well as statistical software packages: The Lenth's method and the estimation of the variance of the effects from the values of those considered negligible. This article shows that neither is better than the other in all cases, and by analyzing the results obtained in a wide variety of situations it provides guidelines on when it is preferable to use one or the other techniqueBrassica aphid (Hemiptera: Aphididae) populations are conditioned by climatic variables and parasitism level: a study case of Triângulo Mineiro, Brazil
http://hdl.handle.net/2117/130097
Brassica aphid (Hemiptera: Aphididae) populations are conditioned by climatic variables and parasitism level: a study case of Triângulo Mineiro, Brazil
Sampaio, M. V.; Korndörfer, A. P.; Pujade Villar, Juli; Hubaide, J.E.A.; Ferreira, S. E.; Arantes, S. O.; Bortoletto, D. M.; Guimarães, C. M.; Sánchez Espigares, Josep Anton; Caballero López, Berta
Cosmopolitan pests such as Brevicoryne brassicae, Lipaphis pseudobrassicae, and Myzus persicae (Aphididae) cause significant damage to Brassicaceae crops. Assessment of the important biotic and abiotic factors that regulate these pests is an essential step in the development of effective Integrated Pest Management programs for these aphids. This study evaluated the influence of leaf position, precipitation, temperature, and parasitism on populations of L. pseudobrassicae, M. persicae, and B. brassicae in collard greens fields in the Triângulo Mineiro region (Minas Gerais state), Brazil. Similar numbers of B. brassicae were found on all parts of the collard green plants, whereas M. persicae and L. pseudobrassicae were found in greatest numbers on the middle and lower parts of the plant. While temperature and precipitation were positively related to aphid population size, their effects were not accumulative, as indicated by a negative interaction term. Although Diaeretiella rapae was the main parasitoid of these aphids, hyperparasitism was dominant; the main hyperparasitoid species recovered from plant samples was Alloxysta fuscicornis. Parasitoids seem to have similar distributions on plants as their hosts. These results may help predict aphid outbreaks and gives clues for specific intra-plant locations when searching for and monitoring aphid populations.
Wed, 06 Mar 2019 12:08:41 GMThttp://hdl.handle.net/2117/1300972019-03-06T12:08:41ZSampaio, M. V.Korndörfer, A. P.Pujade Villar, JuliHubaide, J.E.A.Ferreira, S. E.Arantes, S. O.Bortoletto, D. M.Guimarães, C. M.Sánchez Espigares, Josep AntonCaballero López, BertaCosmopolitan pests such as Brevicoryne brassicae, Lipaphis pseudobrassicae, and Myzus persicae (Aphididae) cause significant damage to Brassicaceae crops. Assessment of the important biotic and abiotic factors that regulate these pests is an essential step in the development of effective Integrated Pest Management programs for these aphids. This study evaluated the influence of leaf position, precipitation, temperature, and parasitism on populations of L. pseudobrassicae, M. persicae, and B. brassicae in collard greens fields in the Triângulo Mineiro region (Minas Gerais state), Brazil. Similar numbers of B. brassicae were found on all parts of the collard green plants, whereas M. persicae and L. pseudobrassicae were found in greatest numbers on the middle and lower parts of the plant. While temperature and precipitation were positively related to aphid population size, their effects were not accumulative, as indicated by a negative interaction term. Although Diaeretiella rapae was the main parasitoid of these aphids, hyperparasitism was dominant; the main hyperparasitoid species recovered from plant samples was Alloxysta fuscicornis. Parasitoids seem to have similar distributions on plants as their hosts. These results may help predict aphid outbreaks and gives clues for specific intra-plant locations when searching for and monitoring aphid populations.Validation and implementation of a diagnostic algorithm for DNA Detection of Bordetella pertussis, B. parapertussis, and B-holmesii in a Pediatric Referral Hospital in Barcelona, Spain
http://hdl.handle.net/2117/129052
Validation and implementation of a diagnostic algorithm for DNA Detection of Bordetella pertussis, B. parapertussis, and B-holmesii in a Pediatric Referral Hospital in Barcelona, Spain
Valero Rello, Anna; Henares Bonilla, Desirée; Acosta Argueta, Lesly María; Jané Checa, Mireia; Godoy Garcia, Pere; Muñoz Almagro, Carmen
This study aimed to validate a comprehensive diagnostic protocolbased on real-time PCR for the rapid detection and identification ofBordetella per-tussis,Bordetella parapertussis, andBordetella holmesii, as well as its implementationin the diagnostic routine of a reference children’s hospital. The new algorithm in-cluded a triplex quantitative PCR (qPCR) targeting IS481gene (inB. pertussis,B. hol-mesii, and someBordetella bronchisepticastrains), pIS1001(B. parapertussis-specific)andrnaseP as the human internal control. Two confirmatory singleplex tests forB.pertussis(ptxA-Pr) andB. holmesii(hIS1001) were performed if IS481was positive. An-alytical validation included determination of linear range, linearity, efficiency, preci-sion, sensitivity, and a reference panel with clinical samples. Once validated, the newalgorithm was prospectively implemented in children with clinical suspicion ofwhooping cough presenting to Hospital Sant Joan de Deu (Barcelona, Spain) over12 months. Lower limits of detection obtained were 4.4, 13.9, and 27.3 genomicequivalents/ml of sample for IS481(onB. pertussis), pIS1001and hIS1001, and 777.9forptxA-Pr. qPCR efficiencies ranged from 86.0% to 96.9%. Intra- and interassay vari-abilities were 3% and 5%, respectively. Among 566 samples analyzed,B. pertus-sis,B. holmesii, andB. parapertussiswere detected in 11.1%, 0.9% (only in females 4 years old), and 0.2% of samples, respectively. The new algorithm proved to be auseful microbiological diagnostic tool for whooping cough, demonstrating a low rateof other non-pertussis Bordetellaspecies in our surveilled area
Wed, 13 Feb 2019 12:56:16 GMThttp://hdl.handle.net/2117/1290522019-02-13T12:56:16ZValero Rello, AnnaHenares Bonilla, DesiréeAcosta Argueta, Lesly MaríaJané Checa, MireiaGodoy Garcia, PereMuñoz Almagro, CarmenThis study aimed to validate a comprehensive diagnostic protocolbased on real-time PCR for the rapid detection and identification ofBordetella per-tussis,Bordetella parapertussis, andBordetella holmesii, as well as its implementationin the diagnostic routine of a reference children’s hospital. The new algorithm in-cluded a triplex quantitative PCR (qPCR) targeting IS481gene (inB. pertussis,B. hol-mesii, and someBordetella bronchisepticastrains), pIS1001(B. parapertussis-specific)andrnaseP as the human internal control. Two confirmatory singleplex tests forB.pertussis(ptxA-Pr) andB. holmesii(hIS1001) were performed if IS481was positive. An-alytical validation included determination of linear range, linearity, efficiency, preci-sion, sensitivity, and a reference panel with clinical samples. Once validated, the newalgorithm was prospectively implemented in children with clinical suspicion ofwhooping cough presenting to Hospital Sant Joan de Deu (Barcelona, Spain) over12 months. Lower limits of detection obtained were 4.4, 13.9, and 27.3 genomicequivalents/ml of sample for IS481(onB. pertussis), pIS1001and hIS1001, and 777.9forptxA-Pr. qPCR efficiencies ranged from 86.0% to 96.9%. Intra- and interassay vari-abilities were 3% and 5%, respectively. Among 566 samples analyzed,B. pertus-sis,B. holmesii, andB. parapertussiswere detected in 11.1%, 0.9% (only in females 4 years old), and 0.2% of samples, respectively. The new algorithm proved to be auseful microbiological diagnostic tool for whooping cough, demonstrating a low rateof other non-pertussis Bordetellaspecies in our surveilled areaEstimating pore water electrical conductivity of sandy soil from time domain reflectometry records using a time-varying dynamic linear model
http://hdl.handle.net/2117/127845
Estimating pore water electrical conductivity of sandy soil from time domain reflectometry records using a time-varying dynamic linear model
Aljoumani, Basem; Sánchez Espigares, Josep Anton; Wessolek, Gerd
Despite the importance of computing soil pore water electrical conductivity (sp) from soil bulk electrical conductivity (sb) in ecological and hydrological applications, a good method of doing so remains elusive. The Hilhorst concept offers a theoretical model describing a linear relationship between sb, and relative dielectric permittivity (eb) in moist soil. The reciprocal of pore water electrical conductivity (1/sp) appears as a slope of the Hilhorst model and the ordinary least squares (OLS) of this linear relationship yields a single estimate ( 1/spˆ ) of the regression parameter vector (sp) for the entire data. This study was carried out on a sandy soil under laboratory conditions. We used a time-varying dynamic linear model (DLM) and the Kalman filter (Kf) to estimate the evolution of sp over time. A time series of the relative dielectric permittivity (eb) and sb of the soil were measured using time domain reflectometry (TDR) at different depths in a soil column to transform the deterministic Hilhorst model into a stochastic model and evaluate the linear relationship between eb and sb in order to capture deterministic changes to (1/sp). Applying the Hilhorst model, strong positive autocorrelations between the residuals could be found. By using and modifying them to DLM, the observed and modeled data of eb obtain a much better match and the estimated evolution of sp converged to its true value. Moreover, the offset of this linear relation varies for each soil depth
Wed, 30 Jan 2019 07:34:00 GMThttp://hdl.handle.net/2117/1278452019-01-30T07:34:00ZAljoumani, BasemSánchez Espigares, Josep AntonWessolek, GerdDespite the importance of computing soil pore water electrical conductivity (sp) from soil bulk electrical conductivity (sb) in ecological and hydrological applications, a good method of doing so remains elusive. The Hilhorst concept offers a theoretical model describing a linear relationship between sb, and relative dielectric permittivity (eb) in moist soil. The reciprocal of pore water electrical conductivity (1/sp) appears as a slope of the Hilhorst model and the ordinary least squares (OLS) of this linear relationship yields a single estimate ( 1/spˆ ) of the regression parameter vector (sp) for the entire data. This study was carried out on a sandy soil under laboratory conditions. We used a time-varying dynamic linear model (DLM) and the Kalman filter (Kf) to estimate the evolution of sp over time. A time series of the relative dielectric permittivity (eb) and sb of the soil were measured using time domain reflectometry (TDR) at different depths in a soil column to transform the deterministic Hilhorst model into a stochastic model and evaluate the linear relationship between eb and sb in order to capture deterministic changes to (1/sp). Applying the Hilhorst model, strong positive autocorrelations between the residuals could be found. By using and modifying them to DLM, the observed and modeled data of eb obtain a much better match and the estimated evolution of sp converged to its true value. Moreover, the offset of this linear relation varies for each soil depthSaving runs in fractional factorial designs
http://hdl.handle.net/2117/127443
Saving runs in fractional factorial designs
Grima Cintas, Pedro; Rodero de Lamo, Lourdes; Tort-Martorell Llabrés, Xavier
When it is known a priori that some contrasts are negligible in a factorial design, their expressions can be used to deduce the missing results. In this article we propose a method for using this procedure when, as in the case of fractional designs, it is not known which contrasts will be null. The method is based on first establishing an interval of possible values corresponding to each of the missing results, then identifying which contrasts are always null independently of the value of said results.
Wed, 23 Jan 2019 12:02:32 GMThttp://hdl.handle.net/2117/1274432019-01-23T12:02:32ZGrima Cintas, PedroRodero de Lamo, LourdesTort-Martorell Llabrés, XavierWhen it is known a priori that some contrasts are negligible in a factorial design, their expressions can be used to deduce the missing results. In this article we propose a method for using this procedure when, as in the case of fractional designs, it is not known which contrasts will be null. The method is based on first establishing an interval of possible values corresponding to each of the missing results, then identifying which contrasts are always null independently of the value of said results.Consequences of using estimated response values from negligible interactions in factorial designs
http://hdl.handle.net/2117/127438
Consequences of using estimated response values from negligible interactions in factorial designs
Xampeny Solani, Rafael; Grima Cintas, Pedro; Tort-Martorell Llabrés, Xavier
This article analyzes the increase in the probability of committing type I and type II errors in assessing the significance of the effects when some properly selected runs have not been carried out and their responses have been estimated from the interactions considered null from scratch. This is done by simulating the responses from known models that represent a wide variety of practical situations that the experimenter will encounter; the responses considered to be missing are then estimated and the significance of the effects is assessed. Through comparison with the parameters of the model, the errors are then identified. To assess the significance of the effects when there are missing values, the Box-Meyer method has been used. The conclusions are that 1 missing value in 8 run designs and up to 3 missing values in 16 run designs experiments can be estimated without hardly any notable increase in the probability of error when assessing the significance of the effects.
Wed, 23 Jan 2019 11:44:04 GMThttp://hdl.handle.net/2117/1274382019-01-23T11:44:04ZXampeny Solani, RafaelGrima Cintas, PedroTort-Martorell Llabrés, XavierThis article analyzes the increase in the probability of committing type I and type II errors in assessing the significance of the effects when some properly selected runs have not been carried out and their responses have been estimated from the interactions considered null from scratch. This is done by simulating the responses from known models that represent a wide variety of practical situations that the experimenter will encounter; the responses considered to be missing are then estimated and the significance of the effects is assessed. Through comparison with the parameters of the model, the errors are then identified. To assess the significance of the effects when there are missing values, the Box-Meyer method has been used. The conclusions are that 1 missing value in 8 run designs and up to 3 missing values in 16 run designs experiments can be estimated without hardly any notable increase in the probability of error when assessing the significance of the effects.