Techniques to Produce and Evaluate Realistic Multivariate Synthetic Data

Background: Proper data modeling in biomedical research requires sufficient data for exploration and reproducibility purposes. A limited sample size can inhibit objective performance evaluation. Objective: We are developing a synthetic population (SP) generation technique to address the limited sample size condition. We show how to estimate a multivariate empirical probability density function (pdf) by converting the task to multiple one-dimensional (1D) pdf estimations. Methods: Kernel density estimation (KDE) in 1D was used to construct univariate maps that converted the input variables (X) to normally distributed variables (Y). Principal component analysis (PCA) was used to transform the variables in Y to the uncoupled representation (T), where the univariate pdfs were assumed normal with specified variances. A standard random number generator was used to create synthetic variables with specified variances in T. Applying the inverse PCA transform to the synthetic variables in T produced the SP in Y. Applying the inverse maps produced the respective SP in X. Multiple tests were developed to compare univariate and multivariate pdfs and covariance matrices between the input (sample) and synthetic samples. Three datasets were investigated (n = 667) each with 10 input variables. Results: For all three datasets, both the univariate (in X, Y, and T) and multivariate (in X, Y, and T) tests showed that the univariate and multivariate pdfs from synthetic samples were statistically similar to their pdfs from the respective samples. Application of several tests for multivariate normality indicated that the SPs in Y were approximately normal. Covariance matrix comparisons (in X and Y) also indicated the same similarity. Conclusions: The work demonstrates how to generate multivariate synthetic data that matches the real input data by converting the input into multiple 1D problems. The work also shows that it is possible to convert a multivariate input pdf to a form that approximates a multivariate normal, although the technique is not dependent upon this finding. Further studies are required to evaluate the generalizability of the approach.

Submerged microfiltration membrane and activated carbon processes for recalcitrant compounds removal in Oil refinery effluent as electrodialysis pre-treatment

The combination of suspended activated carbon (AC) and submerged microfiltration (SMF) processes was applied to polish a biotreated effluent generated in a refinery industry. Preliminary results indicated that Norit 1240 W AC was more suitable than Carbomafra AC brand for Total Organic Carbon (TOC) removal due to the highest Freundlich adsorption constant value (1.97 ± 0.42 and 0.96 ± 0.23 (mg/g)(L/mg)1/n, respectively), thus the first one was used in the combined system. Among all particle sizes of AC tested (0.041–1.01 mm), AC/SMF system was better performed, according to permeation flux, when applying granular AC instead of the powder one. On the other hand, the best response regarding TOC removal and Absorbance at 254 nm (ABS254 nm) reduction were observed when applying powder AC (89 and 97%, respectively). Statistical analysis with Two-sample T-test (p-value <0.05) endorsed the need of both air purge (20 L/h) and backwash strategies (8 min of permeation and 10 seconds of backwash) to diminish fouling occurrence in the SMF system. Finally, it was found that 2 g/L of Norit 1240 W PAC (0.041 mm particle size) condition fitted the effluent to further EDR process (3.4 mg/L TOC) with consistent normalized permeate flux after 5 h of permeation (0.76 ± 0.1 J/J0).

Increasing value through gear flexibility: A case study of U.S. West Coast Sablefish

This paper explores the potential economic gains of allowing additional flexibility in gear-choice, within rights-based management programs. A case study of U.S. West Coast sablefish (Anoplopoma fimbria) provides an example of a commercially important species where gear-switching is currently occurring within the IFQ program, allowing us to isolate the economic potential of gear flexibility along two important margins: size and quality. We conduct a hedonic price analysis of ex-vessel prices using panel fish ticket data and linear mixed-effect econometric models to examine the influences of gear, size, condition, fishing sector, port group, landing month and year on the price of sablefish. We generate a counter-factual scenario that represents the IFQ fishery where the use of fixed-gear is prohibited, by predicting what the size-composition of catch would have been if the sablefish had been caught with trawl gear. We find that the flexibility of targeting sablefish with fixed gear between 2011-2016 generated an annual average 10.45% increase in total revenue, or $1.17M, compared to the trawl-only scenario. These results show sablefish value increases through implementing gear flexibility, which contributes to a broader conversation of allocative efficiency.

Boundedness of vector-valued sublinear operators on weighted Herz-Morrey spaces with variable exponents

If vector-valued sublinear operators satisfy the size condition and the vector-valued inequality on weighted Lebesgue spaces with variable exponent, then we obtain their boundedness on weighted Herz-Morrey spaces with variable exponents.

Snakebite Envenoming a Challenging Diagnosis for the Forensic Pathologist: A Systematic Review

Snakebite envenoming (SBE) is a public health issue in developing countries. The estimated annual global incidence of snakebites is about 5.4 million snakebites per year, resulting from 1.8 to 2.7 million cases of SBE and from 81,000 to 138,000 deaths with 400,000 survivors suffering permanent physical and psychological disabilities. There are more than 3000 species of snakes around the world: 600 are venomous and over 200 are considered to be medically important because of their clinical effects. The severity of SBE depends on several factors among which bite localization, snake’s size, condition of glands and teeth, bite angle and bite duration, the microflora of the snake’s mouth and victim’s skin, age of the victim, weight, health status, and victim’s activity after a bite. Snake venoms are mixtures of protein families, and each of these families contains many different toxins or toxin isoforms. Based on their effects, snake venoms can be classified as hemotoxic, neurotoxic, or cytotoxic and they can all act together involving multiple tissues and organs. When the bite is fatal, the mechanism of death is primarily related to the paralysis of respiratory muscles, which causes asphyxia and hypoxic-ischemic encephalopathy, but also anaphylactic shock, hemorrhagic shock, cardiomyopathy, acute tubular necrosis (ATN). The purpose of this literature review is to evaluate epidemiological and post-mortem examination findings in fatal SBEs in order to better understand the pathophysiological mechanisms, thus helping pathologists in defining the correct diagnosis.

Recursive strategy for decomposing Betti tables of complete intersections

In the spirit of Boij–Söderberg theory, we introduce a recursive decomposition algorithm for the Betti diagram of a complete intersection using the diagram of a complete intersection defined by a subset of the original generators. This alternative algorithm is the main tool that we use to investigate stability and compatibility of the Boij–Söderberg decompositions of related diagrams; indeed, when the biggest generating degree is sufficiently large, the alternative algorithm produces the Boij–Söderberg decomposition. We also provide a detailed analysis of the Boij–Söderberg decomposition for Betti diagrams of codimension four complete intersections where the largest generating degree satisfies the size condition.

Females of a cannibalistic spider control mutilation of their genitalia by males

When females can mate multiply, the interests of both sexes over female remating may not coincide, leading to selection for adaptations and counteradaptations in males and females. In several orb-weaving spiders, males damage external structures of the female genitalia during copulation, which hinders the female from remating. We investigated whether females have control over the mutilation of their genitalia in the orb-weaving spider Larinia jeskovi. We found that female sexual cannibalism during copulation reduced the number of insertions a male was able to perform and hence limited the probability of genital mutilation by the male. Genital mutilation did not differ between treatments in which females experienced different availabilities of other males before the mating trial: males absent, males near the female (“vicinity group”), and males in the female’s web (“web group”). However, traits of the mating male (size, condition) were significantly correlated with the occurrence of cannibalism during mating in “web” and “vicinity” treatments. These results suggest that females have control over mutilation by an early termination of mating, can respond to the availability of potential mates and can alter the probability of mutilation according to certain male traits. Female sexual cannibalism may represent a counteradaptation to genital mutilation allowing females to mate multiply.