Automatic detection of discordant outliers via the Ueda's method

The importance of identifying outliers in a data set is well known. Although variousoutlier detection methods have been proposed in order to enable reliable inferencesregarding a data set, a simple but less known method has been proposed by Ueda(1996/2009). Since this new method, called Uedas method, has not been systematicallyanalysed in previous research, a simulation study addressing its performance androbustness is presented. Although the method was derived assuming that theunderlying data is normally distributed, its performance was analysed using data fromvarious outlier-prone distributions commonly found in several research fields. Theresults obtained enable us to define the strengths and weaknesses of the methodalong with its limits of applicability. Furthermore, an unforeseen field of application ofthe method, which requires further studies was also identified

Innovation, public support and productivity in Colombia

We investigate the association between perceived barriers to innovation and the allocation of public support for innovation in manufacturing and service industries in Colombia, as well as the potential heterogeneity of returns to innovation across the firm-level productivity distribution. We extend the CDM recursive system by including an equation for the allocation of direct support and using quantile regression methods to estimate the productivity equation. We find some differences across manufacturing and service industries. Financing constraints are correlated with obtaining public support in manufacturing and in some services, but in knowledge intensive services (KIS) barriers associated with regulations are more significant. The introduction of innovations increases mostly the productivity of firms below the median of the productivity distribution, especially in services. Increasing human capital would boost productivity of firms in all industries, providing support to the hypothesis that human capital is indeed a bottleneck for productivity growth across the board in Colombia. We conclude that addressing factors that hinder innovation by low productivity firms in all service industries could significantly contribute to increasing productivity and reduce its dispersion

Protected land enhances the survival of native aquatic macrophytes and limits invasive species spread in the Panama Canal

1. This study examined whether protected land in a tropical reservoir's catchment can promote the survival of native aquatic plants (macrophytes) and limit the spread of invasive alien plant species (macrophyte IAS), which can threaten native wildlife and require expensive remediation. As the number of tropical river dams is expected to increase in the coming decades to meet societal demands, it is crucial to explore solutions for preserving aquatic biodiversity. 2. The study used a before–after–control–intervention design, based on monitoring data and long-term sedimentological, climatic and ecological records from both lake and river zones adjacent to protected and unprotected lands around the 100-year-old Gatun Lake in the Panama Canal, Panama. The research examined the impact of impoundment and the invasion of Pontederia crassipes (water hyacinth) and Hydrilla verticillata (water thyme) on native macrophyte communities and environmental variables. 3. Lake zones adjacent to protected lands had lower nutrient concentrations, greater variations in water depth profiles and reduced fluctuations in water chemistry than lake zones outside areas of land protection. In addition, the results showed that whereas zones adjacent to unprotected land became dominated by macrophyte IAS, lake zones adjacent to protected areas were more resilient to the spread of macrophyte IAS and were able to maintain viable populations of native pre-dam species for >100 years. 4. This study indicates that protecting land adjacent to tropical reservoirs could be a cost-effective solution for preserving aquatic macrophyte biodiversity by retaining nutrients, stabilizing water chemistry, providing habitat heterogeneity and protecting native vegetation, while still supporting terrestrial conservation goals. These findings could aid in planning measures for the hundreds of proposed dam projects across lowland tropical areas and provide new insights into best practices for enhancing river ecosystem resilience

Subsidizing innovation over the business cycle

We investigate whether the impact of direct support for business investment in R&D and innovation varies over the business cycle. We address several questions: whether firms that obtain public support in a recession differ from firms that obtain it during expansions; whether the impact of support is smaller in recessions than in expansions, and whether effects vary with the treatment pattern. Using firm-level data from Spain during the period 2005 to 2014, we combine propensity score matching and difference-in-differences methods to estimate firms' response to direct support in different phases of the cycle. Two findings stand out. First, while the impact of support on monetary investment in innovation is pro-cyclical, it is countercyclical in terms of the employee-time allocation to innovation activities. Second, the additionality of a one-year treatment is smaller than that of longer treatments, or repeate program participation. Firms receiving public support during the recession have assigned more employee time to innovation activities than a matched control group, preventing a decline of knowledge capital during the big recessio

A new pipeline for structural characterization and classification of RNA-Seq microbiome data

Background High-throughput sequencing enables the analysis of the composition of numerous biological systems, such as microbial communities. The identification of dependencies within these systems requires the analysis and assimilation of the underlying interaction patterns between all the variables that make up that system. However, this task poses a challenge when considering the compositional nature of the data coming from DNA-sequencing experiments because traditional interaction metrics (e.g., correlation) produce unreliable results when analyzing relative fractions instead of absolute abundances. The compositionality-associated challenges extend to the classification task, as it usually involves the characterization of the interactions between the principal descriptive variables of the datasets. The classification of new samples/patients into binary categories corresponding to dissimilar biological settings or phenotypes (e.g., control and cases) could help researchers in the development of treatments/drugs. Results Here, we develop and exemplify a new approach, applicable to compositional data, for the classification of new samples into two groups with different biological settings. We propose a new metric to characterize and quantify the overall correlation structure deviation between these groups and a technique for dimensionality reduction to facilitate graphical representation. We conduct simulation experiments with synthetic data to assess the proposed method’s classification accuracy. Moreover, we illustrate the performance of the proposed approach using Operational Taxonomic Unit (OTU) count tables obtained through 16S rRNA gene sequencing data from two microbiota experiments. Also, compare our method’s performance with that of two state-of-the-art methods. Conclusions Simulation experiments show that our method achieves a classification accuracy equal to or greater than 98% when using synthetic data. Finally, our method outperforms the other classification methods with real datasets from gene sequencing experiments

The spanish body image state scale: factor structure, reliability and validity in a colombian population

Objective: Body image is a construct highly dependent on culture and ethnicity. Furthermore, recent studies reveal that body image is not only a trait, but also a momentary state subject to change in diverse situational contexts. However, cultural influences on momentary body image have not been sufficiently investigated. To assess the influence of Latin American culture on momentary body image and to enable its comparison to Western countries, the Spanish translation of an existing state body image scale such as the Body Image States Scale (BISS) is needed. In addition, the factor structure, reliability and general validity of the Spanish BISS (S-BISS) should be evaluated prior to its application in diverse situational contexts. Method: We conducted a cross-sectional study evaluating 1137 individuals between the ages of 18 and 28 years from Barranquilla, Colombia, South America. The original BISS, which assesses body satisfaction, was translated from English to Spanish. Factorial structure, scale score reliability and convergent/divergent validity were assessed. Results: Exploratory and confirmatory factor analyses revealed that a one-factor model with correlated items best described the factorial structure present in the BISS questionnaire. The coefficient of scale score reliability was a = 0.92 (McDonalds & = 0.93), with similar results for men and women. Significant differences between males and females were found with lesser body satisfaction in females (W = 163260, p = 0.016). Lower S-BISS scores indicating less body satisfaction were associated with higher BMI (r = −0.287, p < 0.001) and obtained in participants who were currently on a diet (t1135 = −3.98, p < 0.001). The S-BISS was negatively correlated with a trait body image measurement assessing body dissatisfaction (Body Shape Questionnaire, r = −0.577, p < 0.001) and a psychopathology questionnaire (Brief Symptom Inventory 53, r = −0.331, p < 0.001). Conclusion: The S-BISS is a valid and reliable instrument to assess body image in the Colombian population, and exhibits similar psychometric properties to those of the original version. Future studies should examine whether the S-BISS captures change in state body image when applied in diverse situational contexts

Neuropsychological Performance in Patients with Asymptomatic HIV-1 Infection

Human immunodeficiency virus (HIV-1) infection and acquired immunodeficiency syndrome (AIDS) lead to neurocognitive disorders; however, there is still much knowledge to be gained regarding HIV-associated neurocognitive disorders. The purpose of this study was to assess the cognitive performance, instrumental activities of daily living, depression, and anxiety in patients with asymptomatic HIV-1 infections compared with seronegative participants without neurocognitive impairment. We studied a sample consisted of 60 patients with asymptomatic HIV-1 infections and 60 seronegative participants without neurocognitive impairment from the city of Barranquilla, Colombia, with a mean age of 36.07 years. A protocol of neuropsychological and psychopathological tests was applied to the participants. The group of patients with asymptomatic HIV infections significantly underperformed on tasks that assessed global cognitive screening, attention span, learning, phonemic verbal fluency, auditory-verbal comprehension, information processing speed, cognitive flexibility, and motor skills compared to the group of seronegative participants. No significant differences were found in memory, visual confrontation naming, vocabulary, inhibition, and instrumental activities of daily living. Additionally, the patients with asymptomatic HIV-1 infection had a higher anxiety index than the seronegative participants, but no significant difference was found in depression. A correlation was found between depression and anxiety. In conclusion, the patients with asymptomatic HIV-1 infection had lower cognitive performances than the seronegative participants in the cognitive functions mentioned above and more anxiety but still performed the instrumental activities of daily living

ADGRL3 (LPHN3) variants predict substance use disorder

Factors genètics; Desordre d'ús de substànciesFactores genéticos; Desorden de uso de sustanciasGenetic factors; Substance use disorder; ADGRL3 (LPHN3)Genetic factors are strongly implicated in the susceptibility to develop externalizing syndromes such as attention-deficit/hyperactivity disorder (ADHD), oppositional defiant disorder, conduct disorder, and substance use disorder (SUD). Variants in the ADGRL3 (LPHN3) gene predispose to ADHD and predict ADHD severity, disruptive behaviors comorbidity, long-term outcome, and response to treatment. In this study, we investigated whether variants within ADGRL3 are associated with SUD, a disorder that is frequently co-morbid with ADHD. Using family-based, case-control, and longitudinal samples from disparate regions of the world (n = 2698), recruited either for clinical, genetic epidemiological or pharmacogenomic studies of ADHD, we assembled recursive-partitioning frameworks (classification tree analyses) with clinical, demographic, and ADGRL3 genetic information to predict SUD susceptibility. Our results indicate that SUD can be efficiently and robustly predicted in ADHD participants. The genetic models used remained highly efficient in predicting SUD in a large sample of individuals with severe SUD from a psychiatric institution that were not ascertained on the basis of ADHD diagnosis, thus identifying ADGRL3 as a risk gene for SUD. Recursive-partitioning analyses revealed that rs4860437 was the predominant predictive variant. This new methodological approach offers novel insights into higher order predictive interactions and offers a unique opportunity for translational application in the clinical assessment of patients at high risk for SUDR01 DA039881/DA/NIDA NIH HHS/United States. DA039881/U.S. Department of Health & Human Services NIH, National Institute on Drug Abuse (NIDA)

Utility of a Short Neuropsychological Protocol for Detecting HIV-Associated Neurocognitive Disorders in Patients with Asymptomatic HIV-1 Infection

Human Immunodeficiency Virus type 1 (HIV-1) infection is a chronic disease that affects ~40 million people worldwide. HIV-associated neurocognitive disorders (HAND) are common in individuals with HIV-1 Infection, and represent a recent public health problem. Here we evaluate the performance of a recently proposed short protocol for detecting HAND by studying 60 individuals with HIV-1-Infection and 60 seronegative controls from a Caribbean community in Barranquilla, Colombia. The short evaluation protocol used significant neuropsychological tests from a previous study of asymptomatic HIV-1 infected patients and a group of seronegative controls. Brief screening instruments, i.e., the Mini-mental State Examination (MMSE) and the International HIV Dementia Scale (IHDS), were also applied. Using machine-learning techniques, we derived predictive models of HAND status, and evaluated their performance with the ROC curves. The proposed short protocol performs exceptionally well yielding sensitivity, specificity, and overall prediction values >90%, and better predictive capacity than that of the MMSE and IHDS. Community-specific cut-off values for HAND diagnosis, based on the MMSE and IHDS, make this protocol suitable for HAND screening in individuals from this Caribbean community. This study shows the effectivity of a recently proposed short protocol to detect HAND in individuals with asymptomatic HIV-1-Infection. The application of community-specific cut-off values for HAND diagnosis in the clinical setting may improve HAND screening accuracy and facilitate patients’ treatment and follow-up. Further studies are needed to assess the performance of this protocol in other Latin American populations