Association studies of genetic variants and obesity and/or obesity-related risk factors have yielded contradictory results. The aim of the present study was to determine the possible association of ...five single-nucleotide polymorphisms (SNPs) located in the IGF2, LEPR, POMC, PPARG, and PPARGC1 genes with obesity or obesity-related risk phenotypes. This case-control study assessed overweight (n=192) and normal-weight (n=211) children and adolescents. The SNPs were analyzed using minisequencing assays, and variables and genotype distributions between the groups were compared using one-way analysis of variance and Pearson's chi-square or Fisher's exact tests. Logistic regression analysis adjusted for age and gender was used to calculate the odds ratios (ORs) for selected phenotype risks in each group. No difference in SNP distribution was observed between groups. In children, POMC rs28932472(C) was associated with lower diastolic blood pressure (P=0.001), higher low-density lipoprotein (LDL) cholesterol (P=0.014), and higher risk in overweight children of altered total cholesterol (OR=7.35, P=0.006). In adolescents, IGF2 rs680(A) was associated with higher glucose (P=0.012) and higher risk in overweight adolescents for altered insulin (OR=10.08, P=0.005) and homeostasis model of insulin resistance (HOMA-IR) (OR=6.34, P=0.010). PPARG rs1801282(G) conferred a higher risk of altered insulin (OR=12.31, P=0.003), and HOMA-IR (OR=7.47, P=0.005) in overweight adolescents. PARGC1 rs8192678(A) was associated with higher triacylglycerols (P=0.005), and LEPR rs1137101(A) was marginally associated with higher LDL cholesterol (P=0.017). LEPR rs1137101(A) conferred higher risk for altered insulin, and HOMA-IR in overweight adolescents. The associations observed in this population suggested increased risk for cardiovascular diseases and/or type 2 diabetes later in life for individuals carrying these alleles.
The uncertainty associated with option price predictions has largely been overlooked in the literature. This paper aims to fill this gap by quantifying such uncertainty using conformal prediction. ...Conformal prediction is a model-agnostic procedure that constructs prediction intervals, ensuring valid coverage in finite samples without relying on distributional assumptions. Through the simulation of synthetic option prices, we find that conformal prediction generates prediction intervals for gradient boosting machines with an empirical coverage close to the nominal level. Conversely, non-conformal prediction intervals exhibit empirical coverage levels that fall short of the nominal target. In other words, they fail to contain the actual option price more frequently than expected for a given coverage level. As anticipated, we also observe a decrease in the width of prediction intervals as the size of the training data increases. However, we uncover significant variations in the width of these intervals across different options. Specifically, out-of-the-money options and those with a short time-to-maturity exhibit relatively wider prediction intervals. Then, we perform an empirical study using American call and put options on individual stocks. We find that the empirical results replicate those obtained in the simulation experiment.
•Conformal prediction quantifies well the uncertainty of option price predictions.•Conformal prediction intervals have empirical coverage near the nominal level.•Non-conformal prediction intervals have empirical coverage below the nominal level.•Large variations in prediction intervals are found for American call and put options.•Larger intervals are found for out-of-the-money and short time-to-maturity options.
In many domains, the combined opinion of a committee of experts provides better decisions than the judgment of a single expert. This paper shows how to implement a successful ensemble strategy for ...predicting recovery rates on defaulted debts. Using data from Moody’s Ultimate Recovery Database, it is shown that committees of models derived from the same regression method present better forecasts of recovery rates than a single model. More accurate predictions are observed whether we forecast bond or loan recoveries, and across the entire range of actual recovery values.
Abstract
Background
Deaths from diseases of the circulatory system and ischemic heart diseases are declining, but slowly in developing countries, emphasizing its probable relationship with ...determinants of social vulnerability.
Objectives
To analyze the temporal progression of mortality rates of diseases of the circulatory system and ischemic heart diseases from 1980 to 2019 and the association of the rates with the Municipal Human Development Index and Social Vulnerability Index in Brazil.
Methods
We estimated the crude and standardized mortality rates of diseases of the circulatory system and ischemic heart diseases and analyzed the relationship between the obtained data and the Municipal Human Development Index and Social Vulnerability Index. Data on deaths and population were obtained from the DATASUS. The Municipal Human Development Index and the Social Vulnerability Index of each federative unit were extracted from the websites
Atlas Brazil
and
Atlas of Social Vulnerability
, respectively.
Results
The age-standardized mortality rates of diseases of the circulatory system and ischemic heart diseases showed a downward trend nationwide, which was unequal across the federative units. There was an inversely proportional relationship between the standardized mortality rates of diseases of the circulatory system and ischemic heart diseases and the Municipal Human Development Index. The downward mortality trend was observed when the indices were greater than 0.70 and 0.75, respectively. The Social Vulnerability Index was directly proportional to the standardized mortality rates of diseases of the circulatory system and ischemic heart diseases. An upward mortality trend was observed with a Social Vulnerability Index greater than 0.35.
Conclusions
Social determinants represented by the Municipal Human Development Index and the Social Vulnerability Index were related to mortality from diseases of the circulatory system and ischemic heart diseases across the Brazilian federative units. The units with most development and least social inequalities had the lowest mortality from these causes. The most vulnerable die the most.
Is there only one electric eel species? For two and a half centuries since its description by Linnaeus, Electrophorus electricus has captivated humankind by its capacity to generate strong electric ...discharges. Despite the importance of Electrophorus in multiple fields of science, the possibility of additional species-level diversity in the genus, which could also reveal a hidden variety of substances and bioelectrogenic functions, has hitherto not been explored. Here, based on overwhelming patterns of genetic, morphological, and ecological data, we reject the hypothesis of a single species broadly distributed throughout Greater Amazonia. Our analyses readily identify three major lineages that diverged during the Miocene and Pliocene-two of which warrant recognition as new species. For one of the new species, we recorded a discharge of 860 V, well above 650 V previously cited for Electrophorus, making it the strongest living bioelectricity generator.
The work makes use of the scanning vibrating electrode technique (SVET) and the scanning electrochemical microscope (SECM) to investigate microscopic aspects of the electrochemical reactions that ...occur in an iron–zinc galvanic couple immersed in aqueous sodium chloride solution. Detection of the corrosion processes was made by sensing the phenomena occurring in solution. The SVET provided information on the distribution of ionic currents arising from the metal surface, whereas the SECM measured the concentration of chemical species relevant to the corrosion processes. The two techniques had comparable sensitivity for the corrosion of iron but significant differences were observed concerning the detection of corrosion of zinc.
•The softening process of Al–30wt%Zn alloy during high pressure torsion (HPT).•Development of a new microstructure-based model (MBWG).•Effect of the solid solution decomposition, Orowan looping and ...dislocation density.•Observation of the strong grain refinement during HPT.•Simulation of the softening and saturation processes of Al–Zn alloy during HPT.
In this work, super saturated solid solution Al–30wt%Zn alloy was subjected to high pressure torsion (HPT). The material properties and microstructural evolution were experimentally studied. Despite strong grain refinement during HPT, the process of softening is observed. Such a material behavior is captured by a proposed model (MBWG) that takes into consideration the effects of solid solution hardening, Orowan looping and evolution of the dislocation density. Namely, the softening process occurred during HPT is attributed to decomposition of super saturated solid solution and evolution of the dislocation mean free path with plastic strain. Our simulation shows that the proposed model describes well the softening and saturation processes, and the decomposition of solid solution plays a significant role during the HPT process.
Phylogenetic analyses of
Rhipicephalus sanguineus group specimens separated New World specimens into two distinct clades, one represented by haplotypes A–C, together with African specimens, and ...another with haplotypes D–F, together with European specimens.
Phylogenetic analyses based on mitochondrial 16S rDNA sequences were generated from
Rhipicephalus sanguineus group specimens collected in 29 localities among 9 Latin-American countries, plus ticks collected in South Africa, Spain, and Italy. Sequences from Latin America generated six different haplotypes (A, B, C, D, E, and F). Phylogenetic analyses generated trees that segregated our tick sequences into two distinct clades: one is represented by haplotypes A–C, and South African
R. sanguineus and
Rhipicephalus turanicus ticks; the second clade is represented by haplotypes D–F, and European
R. sanguineus and
R. turanicus ticks. When haplotypes A–F are plotted in the Latin America map according to their geographical coordinates, it is clearly seen that haplotypes D–F are restricted to the southern portion of this continent, whereas haplotypes A–C are distributed in areas between northern Mexico and Brazil (except for the extreme south of this last country, where haplotype E was present). Hence, our phylogenetic analyses separated New World specimens of
R. sanguineus into two distinct clades, one represented by tropical and subtropical populations (haplotypes A–C), here designated as the ‘tropical’ species. On the other hand, haplotypes D–F are here designated as the ‘temperate’ species because of their distribution in the southern portion of South America. Until recently, it was assumed that the
R. sanguineus group was represented by a single species in the New World, namely
R. sanguineus. While the present results coupled with recent studies support the presence of at least two species under the taxon
R. sanguineus in the New World, they also show that even in the Old World, the taxon
R. sanguineus might be represented by more than one species, since our phylogenetic analysis segregated European and South African
R. sanguineus ticks into two distinct clades. The same can be applied for Spanish and South African
R. turanicus.
Ichthyological surveys have traditionally been conducted using whole-specimen, capture-based sampling with varied but conventional fishing gear. Recently, environmental DNA (eDNA) metabarcoding has ...emerged as a complementary, and possible alternative, approach to whole-specimen methodologies. In the tropics, where much of the diversity remains undescribed, vast reaches continue unexplored, and anthropogenic activities are constant threats; there have been few eDNA attempts for ichthyological inventories. We tested the discriminatory power of eDNA using MiFish primers with existing public reference libraries and compared this with capture-based methods in two distinct ecosystems in the megadiverse Amazon basin. In our study, eDNA provided an accurate snapshot of the fishes at higher taxonomic levels and corroborated its effectiveness to detect specialized fish assemblages. Some flaws in fish metabarcoding studies are routine issues addressed in natural history museums. Thus, by expanding their archives and adopting a series of initiatives linking collection-based research, training and outreach, natural history museums can enable the effective use of eDNA to survey Earth's hotspots of biodiversity before taxa go extinct. Our project surveying poorly explored rivers and using DNA vouchered archives to build metabarcoding libraries for Neotropical fishes can serve as a model of this protocol.
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•Mg-Gd PVD coatings have been deposited onto Mg5Gd magnesium alloy pins.•The coating is effective in corrosion protection of Mg5Gd magnesium pins.•The protection mechanism involved ...sacrificial anodic dissolution of the PVD coating.•Galvanic current, OCP and SVET measurements supported galvanic protection mechanism.•The polished pin and PVD coating displayed similar VPD levels measured by SKPFM.
In this work metallic pins made of Mg5Gd alloy were coated with magnetron sputtered PVD Mg5Gd layers. Immersion tests in Hank’s balanced salt solution (HBSS) were performed. The PVD coating drastically reduced the corrosion rate of the Mg5Gd pin. The corrosion mechanism of the coating was studied in model electrochemical measurements by Scanning Vibrating Electrode Technique and galvanic current measurements. The tests revealed the preferential anodic dissolution of the Mg5Gd coating galvanically coupled with the bulk Mg5Gd pin. Local measurements of Volta potential difference revealed the VPD contrast between the pin and the coating surfaces only after immersion in HBSS.
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