Correlation analysis of anemia and renal function decline in patients with IgA nephropathy by using generalized additive mixed model / 中华肾脏病杂志

Objective:To investigate the relationship between anemia and renal function prognosis in IgA nephropathy (IgAN) patients.Methods:Patients diagnosed with IgAN by renal biopsy in Shenzhen Second People′s Hospital (The First Affiliated Hospital of Shenzhen University) from January 1, 2010 to December 31, 2018 were retrospectively analyzed. Patients who lacked baseline estimated glomerular filtration rate (eGFR), or patients with the baseline eGFR<15 ml·min -1·(1.73 m 2) -1, or patients who lacked baseline hemoglobin data were excluded. Clinical data, laboratory data, pathological data and follow-up data of renal function were collected. Patients were divided into anemic group (hemoglobin level<120 g/L in males and<110 g/L in females) and non-anemic group. A generalized additive mixed model (GAMM) was used to analyze the relationship between anemia at baseline and decreased renal function (eGFR) in follow-up. Results:A total of 821 IgAN patients were enrolled in this study, including 666 non-anemia patients and 155 anemia patients. There were 397 males (48.36%), aged (34.91±9.46) years. The median baseline eGFR was 72.00(15.00, 167.46) ml·min -1·(1.73 m 2) -1, and the median baseline urinary protein quantification was 1.00(0.01, 15.82) g/24 h. The median follow-up time was 176(0, 3 770) days. A total of 2 352 repeated measurements were performed of which 1 268 (53.91%) repeated measurements were from males. Compared with those in non-anemia group, patients in anemia group had lower levels of baseline eGFR, body mass index (BMI) and serum albumin, higher proportion of females, and higher pathologic manifestations of glomerular segmental sclerosis (S1), tubulointerstitial atrophy/fibrosis (T1 and T2), and crescent (C1 and C2) (all P<0.05). Using the single-factor GAMM, the eGFR decreased by 4.778 ml·min -1·(1.73 m 2) -1 (95% CI 2.727-6.830, P<0.001) more per year in the anemia group than that in the non-anemia group. After adjusting for age, gender, BMI, blood uric acid, mean arterial pressure, serum albumin, blood cholesterol, 24 h urinary protein, glomerular mesangial cell proliferation (M), capillary cell proliferation (E), glomerular segmental sclerosis (S), tubulointerstitial atrophy/fibrosis (T), and crescent formation (C), each additional year of time, eGFR decreased by 6.817 ml·min -1·(1.73 m 2) -1 (95% CI 4.245-9.388, P<0.001) more in the anemia group than that in the non-anemia group. Conclusions:Anemia is correlated with renal function decline in IgAN patiens. IgAN patients with anemia have accelerated deterioration of progress. Early intervention of anemia might delay renal function progression.

Latent categories of adolescents' short video media use tendency and their relationships with personality traits / 中华行为医学与脑科学杂志

Objective:To explore the latent categories of short video media use tendency among adolescents and the influence of personality traits on different categories.Methods:Totally 1 362 adolescents were tested by the five factors of adolescent personality questionnaire and the problematic short video media use scale in March 2022.SPSS 26.0 software was used for data collation and descriptive statistics.Mplus 8.3 software was used for latent profile analysis (LPA) to explore the latent categories of adolescents’ short video media use tendency.Regression mixed model (R3STEP) was used to explore the relationship between different categories of short video media use tendency and personality traits.Results:The short video media use tendency among adolescents was divided into 4 latent categories (by proportion from low to high): " problematic short video media use tendency type" (C4, 11%), " safe short video media use tendency type" (C3, 21%), " social short video media use tendency type" (C1, 29%), and " transitional short video media use tendency type" (C2, 39%). Different personality traits had different effects on the 4 latent categories of short video media use tendency, and using C3 as a reference, openness ( OR=1.95) was a triggering predictor of C1, neuroticism ( OR=0.72) was a protective predictor of C1; cautiousness ( OR=0.46) was a protective predictor of C2, neuroticism ( OR=1.60) was a triggering predictor of C2; cautiousness ( OR=0.33) was a protective predictor of C4, neuroticism ( OR=3.24) was a triggering predictor of C4. Conclusion:There are four different latent categories of Chinese adolescents' short video media use tendency, respectively " safe" , " social" , " transitional" and " problematic" . Further research reveal that, personality traits have a significant impact on the different categories of adolescents' short video media use tendency.This study suggests that educators reasonably guide " transitional" , intervene " problematic" , and focus on helping adolescents with high neuroticism to effectively regulate their negative emotions and reduce the occurrence of problematic short video use.

Application of adjusted limited dependent variable mixed model in the mapping of pharmacoeconomic health utility scale / 中国药房

OBJ ECTIVE To introduce adjusted limited dependent variable mixed model （ALDVMM）and study its application in mapping research ，so as to provide reference for pharmacoeconomic evaluation that needs to obtain health utility value through mapping. METHODS Using the method of literature research ，ALDVMM was introduced from the aspects of development background，model principle ，model determination and test ，model advantages and the current application of the model in empirical research. RESULTS & CONCLUSIONS ALDVMM is a mixed model developed by foreign scholars for the truncation and multimodality phenomenon of EuroQoL group ’s 5D（EQ-5D）at the health utility value 1. Compared with the traditional model，ALDVMM is feasible and has more advantages ，and can more effectively and flexibly capture the actual distribution of EQ-5D and deal with the boundary value problem ，which is helpful to obtain the health utility value more accurately and efficiently and carry out high-quality pharmacoeconomic evaluation.

Analysis of salary characteristics and influencing factors of personnel expenditure in medical institutions in Sichuan province / 中华医院管理杂志

Objective:To analyze the salary characteristics of medical institutions and the influencing factors of personnel expenditure as found in the salary system reform of public hospitals in Sichuan province, for reference in furthering such reform in public hospitals.Methods:The data of personnel expenditure, business operation and medical services came from 96 medical institutions in 21 cities(prefectures)of Sichuan province from 2017 to 2020 by means of institutional survey. The average salary level and salary structure of medical staff were used to describe the salary characteristics, and the total salary was presented by the level of personnel expenditure. The measurement data was represented by M(IQR), the counting data was described by frequency and constituent ratio, and the influencing factors of personnel expenditure were analyzed by generalized linear mixed model. Results:From 2017 to 2020, the personnel expenditure of medical institutions increased by 13.04% annually. In 2020, the per capita salary level of medical staff was 151 900 yuan, while the basic salary and performance salary accounted for 16.20% and 54.60% of personnel expenditure respectively. The analysis results of the generalized linear mixed model showed that the average cost of patients per visit( β=0.596), the level of drugs and sanitary materials consumed per 100 yuan medical income( β=0.286), the number of medical visits( β=0.328), and the years [(2018, 2019, 2020) β=0.025, 0.052, 0.066] were positively correlated to personnel expenditure, while the average length of stay( β=-0.693), the proportion of medical service income( β=-0.392), and the balance rate of income and expenditure( β=-0.062)were negatively correlated to personnel expenditure( P<0.05). The proportion of fiscal subsidy revenue, regional GDP and asset-liability ratio were not the influencing factors of personnel expenditure( P> 0.05). Conclusions:In the reform of the salary system of the province, its salary level of medical institutions has surpassed the current wage ceiling of these institutions. As the salary distribution was mainly made based on the workload, the " baton" role of the salary system reform has begun to pay off. However, the basic guarantee role of compensation has not yet been fully leveraged.Further reform is needed in upgrading refined management, and timely dynamic adjustment of personnel expenditure in combination with the hospital's financial performance and cost analysis, and reasonably optimizing the level of medical staff compensation.

Identification of factors affecting Oncomelania hupensis density in Eastern Dongting Lake regions / 中国血吸虫病防治杂志

Objective To evaluate the impact of water pollutants, water levels and meteorological factors on the Oncomelania hupensis density in Eastern Dongting Lake regions, so as to provide insights into schistosomiasis control. Methods O. hupensis snails were surveyed using a systematic sampling method in snail-infested marshlands in Eastern Dongting Lake regions from 2007 to 2014, and data pertaining to water pollutants, water levels and meteorological factors were collected. The duration of submergence and the date of the start of submergence were calculated. The snail density and its influencing factors were descriptively analyzed, and a linear mixed model was generated to examine the impacts of variables on the snail density. In addition, smooth curves were fitted to investigate the relationship between snail density and variables. Results The snail density appeared a fluctuation in Eastern Dongting Lake regions during the period from 2007 to 2014, with the highest density on October, 2010 (52.79 snails/0.1 m2) and the lowest density on January 2009 (2.15 snails/0.1 m2). Linear mixed-model analysis showed that permanganate index, total phosphorus and the date of the start of submergence affected the snail density (t = 6.386, −2.920 and −3.892, all P values < 0.01). Smooth curve analysis revealed that the associations of the snail density with the permanganate index and total phosphorus appeared an approximately quadratic curve. After the end of April, the earlier date of the start of submergence resulted in a higher snail density. Conclusion Permenganate index, total phosphorus and the date of the start of submergence affect the O. hupensis snail density in Eastern Dongting Lake regions.

Small numbers are an opportunity, not a problem / Números pequenos são uma oportunidade, não um problema

Aims: outcomes of research in education and training are partly a function of the context in which that study takes place, the questions we ask, and what is feasible. Many questions are about learning, which involves repeated measurements in a particular time window, and the practical context is usually such that offering an intervention to some but not to all learners does not make sense or is unethical. For quality assurance and other purposes, education and training centers may have very locally oriented questions that they seek to answer, such as whether an intervention can be considered effective in their context of small numbers of learners. While the rationale behind the design and outcomes of this kind of studies may be of interest to a much wider community, for example to study the transferability of findings to other contexts, people are often discouraged to report on the outcomes of such studies at conferences or in educational research journals. The aim of this paper is to counter that discouragement and instead encourage people to see small numbers as an opportunity instead of as a problem. Method: a worked example of a parametric and a non-parametric method for this type of situation, using simulated data in the zero-cost Open Source statistical program R version 4.0.5. Results: contrary to the non-parametric method, the parametric method can provide estimates of intervention effectiveness for the individual participant, account for trends in different phases of a study. However, the non-parametric method provides a solution in several situations where the parametric method should be used. Conclusion: Given the costs of research, the lessons to be learned from research, and statistical methods available, small numbers should be considered an opportunity, not a problem.

Objetivo: os resultados da pesquisa em educação e treinamento são, em parte, uma função do contexto em que esse estudo ocorre, das perguntas que fazemos e do que é viável. Muitas perguntas são sobre a aprendizagem, que envolve medições repetidas em uma janela de tempo específica, e o contexto prático, geralmente, é tal, que oferecer uma intervenção a alguns, mas não a todos os alunos, não faz sentido ou é antiético. Para garantia de qualidade e outros propósitos, os centros de educação e treinamento podem ter perguntas orientadas localmente que procuram responder, como, por exemplo, se uma intervenção pode ser considerada eficaz em seu contexto de pequeno número de alunos. Embora a justificativa por trás do projeto e dos resultados deste tipo de estudos possa ser do interesse de uma comunidade muito mais ampla, por exemplo, para estudar a possibilidade de transferência de resultados para outros contextos, as pessoas são frequentemente desencorajadas a relatar os resultados de tais estudos em conferências ou em revistas de pesquisa educacional. O objetivo deste artigo é combater esse desânimo e, em vez disso, incentivar as pessoas a verem os pequenos números como uma oportunidade em vez de um problema. Método: realizado um exemplo de método paramétrico e não paramétrico para este tipo de situação, utilizando dados simulados no programa estatístico Open Source R versão 4.0.5 de custo zero. Resultados: ao contrário do método não paramétrico, o método paramétrico pode fornecer estimativas da eficácia da intervenção para o participante individual, levando em conta as tendências em diferentes fases de um estudo. No entanto, o método não paramétrico fornece uma solução em várias situações, onde o método paramétrico deve ser usado. Conclusão: dados os custos da pesquisa, as lições a serem aprendidas com a pesquisa e os métodos estatísticos disponíveis, pequenos números devem ser considerados uma oportunidade, não um problema.

Assessment of individual competence: a sequential mixed model 1 / Avaliação da competência individual: um modelo sequencial misto

Aims: the assessment of individual competence in medical education is about finding a balance between having sufficient resources to make valid and reliable decisions and not using more resources than necessary. Sequential assessment, in which more resources are used for borderline performing candidates than for poorly or clearly satisfactorily performing candidates, can be used to achieve that balance. Although sequential assessment is commonly associated with larger groups of candidates to be assessed, in many practical settings numbers of candidates may be small. Objective: this article presents a single case design with a statistical model for the assessment of individual competence that can be used regardless of the number of candidates. Method: a worked example of a solution that can be used for an individual candidate, using simulated data in the zero-cost Open Source statistical program R version 4.0.5, is provided. Results: the aforementioned solution provides statistics that can be used to make pass/fail decisions at the level of the individual candidate as well as to make decisions regarding the length and timing of an exam (or parts thereof) for the individual candidate. Conclusion: the solution provided can help to reduce resources needed for assessment to a considerable extent while maximizing resources for borderline candidates. This facilitates both decision making and cost reduction in assessment.

Introdução: a avaliação da competência individual na educação médica consiste em encontrar um equilíbrio entre ter recursos suficientes para tomar decisões válidas e confiáveis e não usar mais recursos do que o necessário. A avaliação sequencial, na qual mais recursos são usados para candidatos limítrofes do que para candidatos com desempenho insatisfatório ou claramente satisfatório, pode ser usada para atingir esse equilíbrio. Embora a avaliação sequencial seja comumente associada a grupos maiores de candidatos a serem avaliados, em muitos ambientes práticos, o número de candidatos pode ser pequeno. Objetivo: este artigo apresenta um desenho de caso único com um modelo estatístico de avaliação de competência individual que pode ser utilizado independentemente do número de candidatos. Método: é fornecido um exemplo prático de uma solução que pode ser usada para um candidato individual, usando dados simulados no programa estatístico Open Source de custo zero R versão 4.0.5. Resultados: a solução mencionada fornece estatísticas que podem ser usadas para tomar decisões individuais de aprovação/reprovação para cada candidato, bem como para tomar decisões individualizadas sobre a duração e o tempo de um exame (ou partes dele) para um candidato. Conclusão: a solução fornecida pode ajudar a reduzir consideravelmente os recursos necessários para a avaliação, ao mesmo tempo que maximiza os recursos para os candidatos limítrofes. Isso facilita a tomada de decisões e a redução de custos na avaliação.

Analysis on latent categories of college student′s emotional regulation self-efficacy and its relationship with social anxiety / 中华行为医学与脑科学杂志

Objective:To explore the latent categories of college students′ regulation emotional self-efficacy and its relationship with social anxiety, so as to provide theoretical basis for different groups to implement relevant intervention.Methods:A total of 415 college students were investigated by scale of regulation emotional self-efficacy(SRESE)and interaction anxiousness scale(SIAS). SPSS 26.0 was used for descriptive statistics and data collation, and Mplus 8.3 was used for latent profile analysis (LPA) to explore the potential categories of regulation emotional self-efficacy of college students. The modified BCH method was used to explore the relationship between different categories of regulation emotional self-efficacy and social anxiety.Results:Regulation emotional self-efficacy can be divided into three categories: " high positive expression and low management negative regulation emotional efficiency" , " low regulation emotional efficiency" and " high regulation emotional efficiency" , accounting for 30.3%, 22.3% and 47.4% of all college students. The three categories had different predictive effects on social anxiety. The " high positive expression and low management negative regulation emotional efficiency" (48.66±0.75) and " the low regulation emotional efficacy" (48.05±0.97) had higher scores in social anxiety and there was no significant difference in the prediction of social anxiety between them( χ2=0.24, P=0.62). However, " high regulation emotional efficiency" ( 45.29±0.56) had a lower score on social anxiety, which was significantly different in the prediction of social anxiety compare the other two categories( χ2=6.06, 12.30, both P<0.05). Conclusion:There are three different potential categories of regulation emotional self-efficacy. Different potential categories of regulation emotional self-efficacy have different social anxiety, so targeted intervention methods can be developed to improve the regulation emotional self-efficacy and reduce social anxiety.

Study on genetic structure differences and adjustment strategies in different areas of China / 中华流行病学杂志

Objective To describe the genetic structure of populations in different areas of China,and explore the effects of different strategies to control the confounding factors of the genetic structure in cohort studies.Methods By using the genome-wide association study (GWAS) on data of 4 500 samples from 10 areas of the China Kadoorie Biobank (CKB),we performed principal components analysis to extract the fast and second principal components of the samples for the component two-dimensional diagram generation,and then compared them with the source of sample area to analyze the characteristics of genetic structure of the samples from different areas of China.Based on the CKB cohort data,a simulation data set with cluster sample characteristics such as genetic structure differences and extensive kinship was generated;and the effects of different analysis strategies including traditional analysis scheme and mixed linear model on the inflation factor (λ) were evaluated.Results There were significant genetic structure differences in different areas of China.Distribution of the principal components of the population genetic structure was basically consistent with the geographical distribution of the project area.The first principal component corresponds to the latitude of different areas,and the second principal component corresponds to the longitude of different areas.The generated simulation data showed high false positive rate (λ =1.16),even if the principal components of the genetic structure was adjusted or the area specific subgroup analysis was performed,λ could not be effectively controlled (λ ＞ 1.05);while,by using a mixed linear model adjusting for the kinship matrix,λ was effectively controlled regardless of whether the genetic structure principal component was further adjusted (λ =0.99).Conclusions There were large differences in genetic structure among populations in different areas of China.In molecular epidemiology studies,bias caused by population genetic structure needs to be carefully treated.For large cohort data with complex genetic structure and extensive kinship,it is necessary to use a mixed linear model for association analysis.

Study on genetic structure differences and adjustment strategies in different areas of China / 中华流行病学杂志

Objective To describe the genetic structure of populations in different areas of China,and explore the effects of different strategies to control the confounding factors of the genetic structure in cohort studies.Methods By using the genome-wide association study (GWAS) on data of 4 500 samples from 10 areas of the China Kadoorie Biobank (CKB),we performed principal components analysis to extract the fast and second principal components of the samples for the component two-dimensional diagram generation,and then compared them with the source of sample area to analyze the characteristics of genetic structure of the samples from different areas of China.Based on the CKB cohort data,a simulation data set with cluster sample characteristics such as genetic structure differences and extensive kinship was generated;and the effects of different analysis strategies including traditional analysis scheme and mixed linear model on the inflation factor (λ) were evaluated.Results There were significant genetic structure differences in different areas of China.Distribution of the principal components of the population genetic structure was basically consistent with the geographical distribution of the project area.The first principal component corresponds to the latitude of different areas,and the second principal component corresponds to the longitude of different areas.The generated simulation data showed high false positive rate (λ =1.16),even if the principal components of the genetic structure was adjusted or the area specific subgroup analysis was performed,λ could not be effectively controlled (λ ＞ 1.05);while,by using a mixed linear model adjusting for the kinship matrix,λ was effectively controlled regardless of whether the genetic structure principal component was further adjusted (λ =0.99).Conclusions There were large differences in genetic structure among populations in different areas of China.In molecular epidemiology studies,bias caused by population genetic structure needs to be carefully treated.For large cohort data with complex genetic structure and extensive kinship,it is necessary to use a mixed linear model for association analysis.

Quantitative Study on the Development of Basic Medical Insurance Schemes in China: A Mixed Model Based on Universal Health Coverage / 中国卫生经济

Objective:Based on the perspective of Universal Health Coverage(UHC),a mathematical model was developed to conduct quantitative study on the development status of Basic Medical Insurance Schemes(BMIS) in China.Methods:A mixed model was developed to conduct quantitative study on the development of BMIS in the period of 2003-2015 from five dimensions:coverage of population,benefit package,reimbursement rate,risk pooling level and unity of the schemes.Sensitivity analysis was also performed.Results:The UHC scores for BMIS in China from 2003 to 2015 fluctuated obviously.Given the range of 0-100 percent,the UHC score in 2003 was 52.2％,28.5％ in 2006,23.9％ in 2010 and 26.5％ in 2015.The integration and equalization of BMIS and scaling up the risk pooling levels were shown to contribute significantly to UHC.Conclusion:The construction of mixed models was developed to provide a new calculation assessment tool for measuring the UHC,which consisted of completed evaluation tool package with addition model and multiplication model.Considering the future development of UHC,there is a still long way to go for BMIS in China.Emphases should be given to integration and equalization of BMIS as well as scaling up the risk polling to provincial and national level.

Association between 7-year Changes in Intraocular Pressure and Systemic Factors in Koreans: A Longitudinal Study

PURPOSE: To investigate the changes in intraocular pressure (IOP) and associated systemic factors over 7 years in a healthy Korean population. METHODS: This longitudinal study included healthy subjects with no history of ocular disease and who had been receiving health examinations seven years apart at the Konkuk University Medical Center, Healthcare Center. The participants completed lifestyle questionnaires and underwent general health examinations (blood pressure, height and weight, and blood biochemical tests) and ocular examinations including noncontact tonometry and fundus photography. Subjects with abnormal fundus photography findings and ocular hypertension were excluded. Changes in IOP and systemic factors over 7 years were analyzed. RESULTS: Of 524 possible subjects, 469 were enrolled (55 subjects were excluded: 50 due to abnormal fundus photography and 5 for missing data). The left eye was analyzed in all patients. In all subjects, initial IOP (mean 14.50 ± 3.14 mmHg) was not significantly different from final IOP (14.72 ± 3.38 mmHg) (paired t-test, p = 0.074). In male patients, the final IOP was significantly higher than the initial IOP (paired t-test, p = 0.035). Lifestyle questionnaire variables were associated with a final IOP that was significantly higher than the initial IOP (smokers, alcohol drinkers and less exercisers, paired t-test; p = 0.014, 0.010 and 0.024, respectively). A linear mixed-effects model analysis showed that the change in IOP was negatively associated with age, but this was not statistically significant. Changes in systolic blood pressure (SBP), body mass index (BMI), total cholesterol (T.Chol) and low density lipoprotein (LDL) were positively correlated with change in IOP. CONCLUSIONS: A linear mixed-model analysis showed IOP decreased with age but this was not statistically significant. Changes in SBP, BMI, T.Chol and LDL were significantly positively correlated with change in IOP.

Parasite abundance and its determinants in fishes from Brazil: an eco-epidemiological approach / Abundância parasitária e seus determinantes em peixes do Brasil: uma abordagem ecoepidemiológica

Abstract The variability in parasite abundance has an ecological basis; however, from an epidemiological point of view, the contribution of factors inherent to the host to the variability in parasite abundance remains an open question. A database consisting of 3,746 specimens of 73 fish species was used to verify the relation between the distribution of parasite abundance in fishes and a set of biotic factors inherent to the hosts. Classical and mixed Poisson regression models were constructed. Prevalence ratios (PR) and their respective 95% confidence intervals were estimated. The parasite abundance was significantly higher in female hosts, nonschooling species, species from benthopelagic and pelagic habitats, and fishes with greater body length. Overall, these results suggest that the variability in the abundance of infection is an attribute of the parasite species. Although the results are biologically plausible, important gaps may still exist and should be explored to better understand the variations in parasite abundance, which has great relevance in epidemiological studies. We reinforce the importance of choosing the statistical model most appropriate for the nature of the data to avoid spurious results, especially when the autocorrelation in the data is not taken into account.

Resumo A variabilidade na abundância parasitária tem embasamento na perspectiva ecológica, entretanto, do ponto de vista epidemiológico, permanece em aberto a possibilidade da contribuição de fatores inerentes aos hospedeiros para essa variabilidade. Foram analisados 3.746 espécimes, pertencentes a 73 espécies de peixes, para verificar a relação entre a distribuição da abundância parasitária em peixes e um conjunto de fatores bióticos inerentes aos hospedeiros. Modelos de Regressão de Poisson clássico e misto foram ajustados. As razões de prevalência (RP) e seus respectivos intervalos, com 95% de confiança, foram estimados. A abundância parasitária foi significativamente maior em hospedeiros fêmeas, não formadoras de cardumes, de hábitats bentopelágico e pelágico e com maior comprimento do corporal. De um modo geral, esses resultados sugerem que a abundância de infecção é um atributo da espécie de parasitos que pode ser variável. Apesar dos resultados apresentarem plausibilidade biológica, ainda pode haver lacunas importantes a serem exploradas para o melhor entendimento das variações da abundância parasitária que, por sua vez, tem grande relevância nos estudos epidemiológicos. Reforça-se a importância da escolha de um modelo estatístico mais adequado à natureza dos dados, evitando-se resultados espúrios, principalmente quando não se leva em conta a autocorrelação entre os dados.

Factors associated with parasite dominance in fishes from Brazil / Fatores associados com a dominância parasitária em peixes do Brasil

Abstract The present study used regression models to evaluate the existence of factors that may influence the numerical parasite dominance with an epidemiological approximation. A database including 3,746 fish specimens and their respective parasites were used to evaluate the relationship between parasite dominance and biotic characteristics inherent to the studied hosts and the parasite taxa. Multivariate, classical, and mixed effects linear regression models were fitted. The calculations were performed using R software (95% CI). In the fitting of the classical multiple linear regression model, freshwater and planktivorous fish species and body length, as well as the species of the taxa Trematoda, Monogenea, and Hirudinea, were associated with parasite dominance. However, the fitting of the mixed effects model showed that the body length of the host and the species of the taxa Nematoda, Trematoda, Monogenea, Hirudinea, and Crustacea were significantly associated with parasite dominance. Studies that consider specific biological aspects of the hosts and parasites should expand the knowledge regarding factors that influence the numerical dominance of fish in Brazil. The use of a mixed model shows, once again, the importance of the appropriate use of a model correlated with the characteristics of the data to obtain consistent results.

Resumo Este estudo avaliou, por meio de modelos de regressão e sob o ponto de vista epidemiológico, a existência de fatores que podem influenciar a dominância numérica parasitária. Utilizou-se um banco de dados, contendo 3.746 espécimes de peixes e seus respectivos parasitos, para avaliar a relação da dominância parasitária com características bióticas inerentes aos hospedeiros e aos táxons parasitários estudados. Foram ajustados modelos de regressão linear multivariada, clássico e de efeitos mistos. Os cálculos foram realizados no software R (IC 95%). No ajuste do modelo de regressão linear múltipla clássico, as espécies de peixes dulcícolas, as planctívoras e o comprimento do corpo foram associadas à dominância parasitária, assim como os táxons Trematoda, Monogenea e Hirudínea. Entretanto, o ajuste do modelo de efeitos mistos demonstrou que apenas o comprimento do hospedeiro e os táxons Nematota, Trematoda, Monogenea, Hirudínea e Crustácea estão associados significativamente a dominância parasitária. Estudos que considerem os aspectos biológicos específicos dos hospedeiros e dos parasitos devem ampliar o entendimento sobre os fatores que interferem na dominância numérica em peixes do Brasil. A utilização do modelo misto demonstra, mais uma vez, a importância do uso adequado do modelo que respeite a natureza dos dados para a obtenção de resultados consistentes.

External Quality Assessment of Institutions and Instruments Using a Linear Mixed Model

BACKGROUND: External quality assessment (EQA) uses a standard deviation index (SDI), based on a peer group, to evaluate laboratory performance. However, evaluations using peer group SDIs often have limited applicability, because they are not statistically valid unless the number of institutions in the same peer group is large. The present study proposes a statistical model for simultaneously evaluating the performance of all participating institutions, as well as the performance of instruments on the market. METHODS: By assuming that proficiency test results were affected by the manufacturer, the instrument, and the institution, the effects of those factors were estimated using a linear mixed model. We used these effect estimates to calculate manufacturer, instrument, and institution SDIs. Using simulation, we evaluated the false positive rates and efficiencies of the proposed linear mixed model. RESULTS: Simulations showed that the linear mixed model empirical type I error rates preserved the nominal significance level. This model was also more statistically efficient than the peer group SDI. Rates of unacceptability were lower when using institution SDI than they were when using peer group SDI. Additional outliers that could not be evaluated using the current system were detected by the institution SDI statistic. The instrument SDI statistic detected outliers among different instrument groups. CONCLUSIONS: Institution and instrument SDIs are robust and efficient tools for EQA, and they can replace the currently used system of peer group SDI.

Seleção genética em progênies de Eucalyptus camaldulensis em área de cerrado matogrossense / Genetic selection in Eucalyptus camaldulensis progenies in savanna area of Mato Grosso State, Brazil

O presente trabalho objetivou estimar parâmetros, correlações e ganhos genéticos para caracteres de crescimento e forma, em um teste de progênies deEucalyptus camaldulensisna região centro-oeste do Brasil. Aos três anos de idade, as progênies foram avaliadas quanto aos caracteres: altura total (ALTT), altura comercial (ALTC), diâmetro à altura do peito (DAP) e forma de fuste (FF). A análise de deviance detectou diferenças significativas para os caracteres ALTC, DAP e FF. As estimativas das herdabilidades individuais foram de baixa magnitude para ALTT (0,10) e DAP (0,16), porém, ALTC (0,18) e FF (0,25) apresentaram valores de média a alta magnitude. Os coeficientes de variação genética individual (CVgi%) variaram de 8,59% para FF a 15,91% para ALTC. As correlações fenotípicas e genéticas preditas foram positivas e de alta magnitude entre ALTT e ALTC (0,80 e 0,82, respectivamente) e ALTT e DAP (0,85 e 0,86, respectivamente), indicando que a seleção indireta pode ser utilizada para essas associações. A seleção individual se mostrou superior, quando comparada à seleção entre e dentro. Os valores encontrados indicaram perspectivas de progressos genéticos com seleção baseada nos caracteres avaliados.

This study aimed to estimate parameters, correlations and genetic gain for growth and shape traits in a progeny trial using Eucalyptus camaldulensisin Central Brazil. When it was three years old, progenies were evaluated for the following traits: total height (ALTT), commercial height (ALTC), diameter at breast height (DAP) and stem form (FF). Deviance analysis detected significant differences for ALTC, DAP and FF. Estimates of individual heritability showed low magnitude for ALTT (0.10) and DAP (0.16). However, ALTC (0.18) and FF (0.25), showed median to high magnitude values. Individual genetic variation coefficients (CVgi%), ranged from 8.59% (FF) to 15.91% (ALTC). Predicted phenotypic and genetic correlations were positive and of high magnitude between ALTT and ALTC (0.80 and 0.82) as well as between ALTT and DAP (0.85 and 0.86), indicating that indirect selection can be used for these associations. Individual selection showed to be superior when compared to selection between and within. Found values indicated perspectives of genetic progress with selection based on the evaluated characters.

Regeneration rate after fission in the fissiparous sea star Allostichaster capensis (Asteroidea) / Tasa de regeneración luego de la fisión en la estrella de mar fisipara Allostichaster capensis (Asteroidea)

Abstract Many studies have focused on the regeneration rate of arms in Asteroidea but no studies have focused on the regeneration rate after fission. Allostichaster capensis is a fissiparous sea star with a wide range of distribution. In Golfo Nuevo (42°46'49'' S - 64°59' 26'' W) sea stars undergo fission every spring and summer and regenerate the rest of the year. To analyze the regeneration rate, we conducted an experiment with sea stars collected just before fission. After sea stars underwent fission, the length of the three non-regenerating and the three regenerating arms were measured weekly. The arm length (regenerating and non-regenerating) was used in non-Linear Mixed Effect models in order to account for within-individual correlation in different models. The regenerating arms regenerate according to a Quadratic model, while the non-regenerating arms regenerate according to a linear model. In the regenerating arms, the regeneration rate was estimated to be 0.1 mm.week-1 and in the non-regenerating arms, the growth rate was 0.004 mm.week -1. Sea stars regenerate ca. 20 % of the arm in one month, and it takes about 5 months to be completely regenerated. At the beginning, the regeneration rate is fast generating the growth of the arms, once the pyloric caeca and gonads are present inside the arms the regeneration rate slows down probably due to allocation to gametes and pyloric caeca and arms. The factors that regulate the regeneration rate are unknown. However, food availability and energy storage seem to play an important role. Rev. Biol. Trop. 63 (Suppl. 2): 321-328. Epub 2015 June 01.

Resumen Numerosos estudios se han enfocado en estudiar la tasa de regeneración de brazos en Asteroidea, sin embargo ninguno se han centrado en la tasa de regeneración después del proceso de fisión. Allostichaster capensis es una estrella de mar fisípara con un amplio rango de distribución. En el Golfo Nuevo (42°46'49'' S - 64°59'26'' W) las estrellas de mar se fisionan cada primavera y verano y se regeneran durante el resto del año. Para analizar la tasa de regeneración, se realizó un experimento con estrellas de mar colectadas justo antes de la fisión. Después de estrellas de mar se fisionaron, se midió la longitud de los tres brazos en regeneración y de los tres brazos originales semanalmente. Se utilizaron modelos no lineales de efectos mixtos para analizar la correlación dentro de individuos del largo de los brazos (regenerados y que no regeneran). Los brazos en regeneración, regeneraron sus brazos de acuerdo con un modelo cuadrático, mientras que los brazos originales ajustaron a un modelo lineal. En los brazos de regeneración se estimó que la tasa de regeneración era de 0.1 mm/ semana; mientras que en los brazos originales, la tasa de crecimiento fue de 0.004 mm/semana. Las estrellas de mar se regeneran un 20 % aproximadamente del brazo en un mes, y tardan alrededor de cinco meses en estar completamente regenerado. Al principio, la alta tasa de regeneración genera el crecimiento rápido de los brazos en longitud, una vez que el ciego pilórico y las gónadas están presentes en el interior de los brazos; la tasa de regeneración disminuye, probablemente debido a la asignación de energía en la producción de gametas, en el ciego pilórico y en los brazos. Los factores que regulan la tasa de regeneración son desconocidos. Sin embargo, la disponibilidad de alimentos y el almacenamiento de energía parecen jugar un papel importante.

Use of direct and iterative solvers for estimation of SNP effects in genome-wide selection

The aim of this study was to compare iterative and direct solvers for estimation of marker effects in genomic selection. One iterative and two direct methods were used: Gauss-Seidel with Residual Update, Cholesky Decomposition and Gentleman-Givens rotations. For resembling different scenarios with respect to number of markers and of genotyped animals, a simulated data set divided into 25 subsets was used. Number of markers ranged from 1,200 to 5,925 and number of animals ranged from 1,200 to 5,865. Methods were also applied to real data comprising 3081 individuals genotyped for 45181 SNPs. Results from simulated data showed that the iterative solver was substantially faster than direct methods for larger numbers of markers. Use of a direct solver may allow for computing (co)variances of SNP effects. When applied to real data, performance of the iterative method varied substantially, depending on the level of ill-conditioning of the coefficient matrix. From results with real data, Gentleman-Givens rotations would be the method of choice in this particular application as it provided an exact solution within a fairly reasonable time frame (less than two hours). It would indeed be the preferred method whenever computer resources allow its use.

Curva de crescimento usando modelo misto: uma aplicação na progressão da Doença de Machado-Joseph / Growth curve using mixed model: an application on Machado-Joseph Disease progression

Introdução: A obtenção dos dados por meio de medidas repetidas em diversas ocasiões no tempo em um mesmo sujeito torna possível o ajuste de curvas que descrevam padrões de evolução e identificam preditores de evolução. O objetivo deste trabalho foi ajustar curvas para descrever a progressão da doença de Machado-Joseph (DMJ), quantificada pelo escore NESSCA (Neurological Examination Score for Spinocerebellar Ataxia), utilizando modelos mistos. Métodos: Os dados foram obtidos de uma coorte de pacientes da DMJ acompanhada no Hospital de Clínicas de Porto Alegre (HCPA) durante um período de 10 anos. Nas avaliações clínicas realizadas, o comprometimento clínico do paciente foi mensurado várias vezes através do escore NESSCA. Esse escore foi considerado como desfecho, e a progressão da doença poderia ser influenciada pelas variáveis explicativas: idade no início da doença e comprimento da mutação. O procedimento Proc MIXED do software SAS foi utilizado para realizar o ajuste dos modelos. Resultados: Progressão da doença ocorre mais lentamente com o aumento na idade de início da doença, por outro lado, com o aumento do comprimento da mutação, mais rápida é a progressão da doença. Conclusão: Uma maior idade no início da doença é fator de proteção para a progressão da DMJ e um maior comprimento da mutação é fator de risco. Ressalta-se que as atribuições de proteção e risco estão relacionadas exclusivamente com a velocidade de progressão da doença, não sendo observados efeitos significativos dessas variáveis para o escore no início da doença.

Background: Obtaining data with repeated measures in different occasions, from the same patient, makes the growth curve adjustment possible. These curves describe evolution patterns and identify evolution predictors. The main purpose of this study was to adjust growth curve to describe Machado-Joseph disease progression (MJD), quantified by the NESSCA score (Neurological Examination Score for Spinocerebellar Ataxia) using linear mixed model. Methods: the data were obtained from a cohort of MJD patients observed at Hospital de Clínicas de Porto Alegre (HCPA) during 10 years. In the clinical evaluation performed, the clinical implications of these patients were measured by the NESSCA score. In order to accomplish the data analysis, the NESSCA score was used as an outcome and it was considered that the disease progression could be influenced by explaining variables such as age at onset and CAG length. The procedure Proc MIXED of the software SAS was used to perform the models adjustment. Results: the disease progression is slower with the increase of age at onset, on the other hand, the progression of the disease is faster with CAG length increase. Conclusion: a higher age at onset is a protection factor to the MJD progression and a higher CAG length is a risk factor. It is highlighted that the attributions of protection and risk are exclusively related with the progression speed of the disease, since there were no significant effects of these variables to the score at the beginning of the disease.

Mixed Model in the Hierarchical Classification Datas and Implementation of SAS / 中国卫生统计

Objective To investigate the mixed model in bier-archical classification datas and implementing with mixed model in SAS. Methods Hierarchical classification datas exemplify the mixed model u-sing procedure mixed,and compared with traditional general linear model. Results The example shows the same result between the SAS mixed model and the general linear model. Conclusion SAS MIXED can flexi-bly fit and analysis hieraxchical classification datas.