Use of high resolution microscopy (FESEM and TEM) to investigate carbonate precipitates in association with organic matter from hot spring, salt pond, and reef environments

Carbonate precipitates in biofilm were investigated from hot springs near Viterbo, Italy; Salt Pond, San Salvador; and Fowl Cay Reef, Abaco, Bahamas. Features shared by hot springs and salt ponds are supersaturation with CaCO3, abundant Spirulina, and clustered acicular aragonite crystals termed “fuzzy dumbbells.” TEM and FESEM microscopy show fuzzy dumbbells contain a core of amorphous organic matter and subhedral CaCO3 microcrystals arranged in linear fabrics. Micron- to millimeter-scale microenvironments are identified by localized dissolution, the occurrence of gothic calcite inter-grown with organic filaments, and the presence of calcite in biofilm where aragonite is chemically favored. Spherical CaCO3 precipitates in reefs were anticipated, but not encountered in TEM sections of reef biofilm. In conclusion, biofilm creates the microenvironment and organic matter provides substrate for fuzzy dumbbell precipitation. TEM is a novel technique for studying the relationship between organic matter and CaCO3 precipitation, and has potential medical, industrial, and academic applications

Leaving Home: Demographic, Endocrine, And Behavioral Correlates Of Dispersal In Monogamous Owl Monkeys (aotus Azarae) Of Argentina

Natal dispersal, the movement of individuals from their birthplace to new areas in which they may breed, is an important aspect of life history that influences a variety of processes. Understanding dispersal not only increases our theoretical knowledge of the evolution of mating systems and social dynamics, but also provides insights essential for effective population management and for predicting the consequences that environmental changes may have on species’ distributions. This dissertation takes a holistic approach to explore natal dispersal at the level of the population, group, and individual in Azara’s owl monkey (Aotus azarae), a social monogamous primate native to South America. All data presented in this dissertation were collected at a long-term field site of the Owl Monkey Project in the Gran Chaco region of Formosa, Argentina. Chapter two examines dispersal at the level of the community, by exploring how demographic changes and environmental variables are associated with dispersal. The timing of dispersal was highly flexible, suggesting that delaying dispersal may be an adaptive strategy that owl monkeys utilize to minimize dispersal costs and maintain access to benefits provided by the natal group. Chapter three narrows the focus to the level of the group, and finds that behaviors, particularly agonism among group members, may function to regulate dispersal as well as mediate competition amongst adults and predispersed offspring. The next two chapters narrow the focus even further, to the individual level. Chapter four, which examines hormonal correlates of development and dispersal, finds that females experience the onset of sexual maturity prior to dispersing. Chapter five follows dispersing individuals thorough the entire process of dispersal to investigate the ultimate fates of dispersers. Dispersal strategies were highly variable, but individuals often prospected prior to permanently dispersing and almost always spent time as solitary “floaters”. Together, these investigations provide insight into both proximate and ultimate causes for dispersal and allow for the development of a multifaceted understanding of dispersal patterns in a socially monogamous primate. The holistic approach to understanding dispersal taken in this dissertation is one that could be useful for increasing our understanding of dispersal in many other taxa

Partially sighted children: the visual processing of words and pictures.

Reading is normally by eye and by ear, but what happens if eyesight is severely\ud impaired? The hypothesis put forward in the first part of this thesis is that partially\ud sighted children adopt a predominantly nonlexical word recognition and production\ud strategy. This is likely to be because of the reading tuition they receive, which\ud emphasises individual letters and letter patterns in words in relation to pronunciation.\ud This study explores the word and picture processing abilities of a small group of\ud partially sighted children, using a series of experimental tasks.\ud Surprisingly, the analysis of oral reading errors in Study 1 revealed that the partially\ud sighted children were using the same salient graphic cues as young fully sighted\ud readers were normally found to be using.\ud Further experiments using lexical decision tasks were carried out in Study 2 to\ud investigate more closely the strategies used by partially sighted and matched fully\ud sighted children in relation to lexical and nonlexical processing. Although there was\ud clear evidence of nonlexical processing on the part of partially sighted children, there\ud were also signs of lexical processing, too. Additional evidence was provided by their\ud spellings presented in Study 3. The investigations described here suggest that the\ud compensatory reading tuition experienced by the PS children led to a dominant\ud nonlexical processing strategy, though not to the exclusion of lexical processing.\ud Impaired eyesight was not associated inevitably with poor reading and spelling levels.\ud The second hypothesis is that impaired eyesight is associated with poor visual\ud recognition and recall of pictures, because of difficulty in accurate identification and\ud slow processing. However, under the favourable conditions provided, which included\ud a relatively lengthy exposure time, this was not entirely the case. The ability of the PS\ud children to recognise pictures was remarkably good. Greater difficulty by them with the\ud recall of pictures suggested partial specification of internal representations.\ud These studies were set alongside comparable work with blind children. They contribute\ud to the very sparse literature on PS children and confirm that these children can\ud overcome severe visual handicap to present a profile of skilled accomplishment

The Long Range Gravitational Potential Energy Between Strings

We calculate the gravitational potential energy between infinitely long parallel strings with tensions \tau_1 and \tau_2. Classically, it vanishes, but at one loop, we find that the long range gravitational potential energy per unit length is U/L = 24G_N^2\tau_1\tau_2/(5 \pi a^2) + ..., where a is the separation between the strings, G_N is Newton's constant, and we set \hbar = c =1. The ellipses represent terms suppressed by more powers of G_N \tau_i. Typically, massless bulk fields give rise at one loop to a long range potential between p-branes in space-times of dimension p+2+1. The contribution to this potential from bulk scalars is computed for arbitrary p (strings correspond to p=1) and in the case of three-branes its possible relevance for cosmological quintessence is commented on.Comment: 10 pages, 6 figure

A genotyping array for the globally invasive vector mosquito, Aedes albopictus

Background: Although whole-genome sequencing (WGS) is the preferred genotyping method for most genomic analyses, limitations are often experienced when studying genomes characterized by a high percentage of repetitive elements, high linkage, and recombination deserts. The Asian tiger mosquito (Aedes albopictus), for example, has a genome comprising up to 72% repetitive elements, and therefore we set out to develop a single-nucleotide polymorphism (SNP) chip to be more cost-effective. Aedes albopictus is an invasive species originating from Southeast Asia that has recently spread around the world and is a vector for many human diseases. Developing an accessible genotyping platform is essential in advancing biological control methods and understanding the population dynamics of this pest species, with significant implications for public health. Methods: We designed a SNP chip for Ae. albopictus (Aealbo chip) based on approximately 2.7 million SNPs identified using WGS data from 819 worldwide samples. We validated the chip using laboratory single-pair crosses, comparing technical replicates, and comparing genotypes of samples genotyped by WGS and the SNP chip. We then used the chip for a population genomic analysis of 237 samples from 28 sites in the native range to evaluate its usefulness in describing patterns of genomic variation and tracing the origins of invasions. Results: Probes on the Aealbo chip targeted 175,396 SNPs in coding and non-coding regions across all three chromosomes, with a density of 102 SNPs per 1 Mb window, and at least one SNP in each of the 17,461 protein-coding genes. Overall, 70% of the probes captured the genetic variation. Segregation analysis found that 98% of the SNPs followed expectations of single-copy Mendelian genes. Comparisons with WGS indicated that sites with genotype disagreements were mostly heterozygotes at loci with WGS read depth \u3c 20, while there was near complete agreement with WGS read depths \u3e 20, indicating that the chip more accurately detects heterozygotes than low-coverage WGS. Sample sizes did not affect the accuracy of the SNP chip genotype calls. Ancestry analyses identified four to five genetic clusters in the native range with various levels of admixture. Conclusions: The Aealbo chip is highly accurate, is concordant with genotypes from WGS with high sequence coverage, and may be more accurate than low-coverage WGS. Graphical Abstract: (Figure presented.) © The Author(s) 2024

Germline variation in inflammation-related pathways and risk of Barrett's oesophagus and oesophageal adenocarcinoma

Esophageal adenocarcinoma (EA) incidence has risen sharply in Western countries over recent decades. Local and systemic inflammation, operating downstream of disease-associated exposures, is considered an important contributor to EA pathogenesis. Several risk factors have been identified for EA and its precursor, Barrett’s esophagus (BE), including symptomatic reflux, obesity, and smoking. The role of inherited genetic susceptibility remains an area of active investigation. To explore whether germline variation related to inflammatory processes influences susceptibility to BE/EA, we used data from a genome-wide association study (GWAS) of 2,515 EA cases, 3,295 BE cases, and 3,207 controls. Our analysis included 7,863 single nucleotide polymorphisms (SNPs) in 449 genes assigned to five pathways: cyclooxygenase (COX), cytokine signaling, oxidative stress, human leukocyte antigen, and NFκB. A principal components-based analytic framework was employed to evaluate pathway-level and gene-level associations with disease risk. We identified a significant signal for the COX pathway in relation to BE risk (P=0.0059, FDR q=0.03), and in gene-level analyses found an association with MGST1 (microsomal glutathione-S-transferase 1; P=0.0005, q=0.005). Assessment of 36 MGST1 SNPs identified 14 variants associated with elevated BE risk (q<0.05). Of these, four were subsequently confirmed (P<5.5 × 10−5) in a meta-analysis encompassing an independent set of 1,851 BE cases and 3,496 controls. Three of these SNPs (rs3852575, rs73112090, rs4149204) were associated with similar elevations in EA risk. This study provides the most comprehensive evaluation of inflammation-related germline variation in relation to risk of BE/EA, and suggests that variants in MGST1 influence disease susceptibility

A Genotyping Array for the Globally Invasive Vector Mosquito, Aedes albopictus

BACKGROUND: Although whole-genome sequencing (WGS) is the preferred genotyping method for most genomic analyses, limitations are often experienced when studying genomes characterized by a high percentage of repetitive elements, high linkage, and recombination deserts. The Asian tiger mosquito (Aedes albopictus), for example, has a genome comprising up to 72% repetitive elements, and therefore we set out to develop a single-nucleotide polymorphism (SNP) chip to be more cost-effective. Aedes albopictus is an invasive species originating from Southeast Asia that has recently spread around the world and is a vector for many human diseases. Developing an accessible genotyping platform is essential in advancing biological control methods and understanding the population dynamics of this pest species, with significant implications for public health. METHODS: We designed a SNP chip for Ae. albopictus (Aealbo chip) based on approximately 2.7 million SNPs identified using WGS data from 819 worldwide samples. We validated the chip using laboratory single-pair crosses, comparing technical replicates, and comparing genotypes of samples genotyped by WGS and the SNP chip. We then used the chip for a population genomic analysis of 237 samples from 28 sites in the native range to evaluate its usefulness in describing patterns of genomic variation and tracing the origins of invasions. RESULTS: Probes on the Aealbo chip targeted 175,396 SNPs in coding and non-coding regions across all three chromosomes, with a density of 102 SNPs per 1 Mb window, and at least one SNP in each of the 17,461 protein-coding genes. Overall, 70% of the probes captured the genetic variation. Segregation analysis found that 98% of the SNPs followed expectations of single-copy Mendelian genes. Comparisons with WGS indicated that sites with genotype disagreements were mostly heterozygotes at loci with WGS read depth \u3c 20, while there was near complete agreement with WGS read depths \u3e 20, indicating that the chip more accurately detects heterozygotes than low-coverage WGS. Sample sizes did not affect the accuracy of the SNP chip genotype calls. Ancestry analyses identified four to five genetic clusters in the native range with various levels of admixture. CONCLUSIONS: The Aealbo chip is highly accurate, is concordant with genotypes from WGS with high sequence coverage, and may be more accurate than low-coverage WGS

Genetic and environmental influences on human height from infancy through adulthood at different levels of parental education

Genetic factors explain a major proportion of human height variation, but differences in mean stature have also been found between socio-economic categories suggesting a possible effect of environment. By utilizing a classical twin design which allows decomposing the variation of height into genetic and environmental components, we tested the hypothesis that environmental variation in height is greater in offspring of lower educated parents. Twin data from 29 cohorts including 65,978 complete twin pairs with information on height at ages 1 to 69 years and on parental education were pooled allowing the analyses at different ages and in three geographic-cultural regions (Europe, North America and Australia, and East Asia). Parental education mostly showed a positive association with offspring height, with significant associations in mid-childhood and from adolescence onwards. In variance decomposition modeling, the genetic and environmental variance components of height did not show a consistent relation to parental education. A random-effects meta-regression analysis of the aggregate-level data showed a trend towards greater shared environmental variation of height in low parental education families. In conclusion, in our very large dataset from twin cohorts around the globe, these results provide only weak evidence for the study hypothesis.Peer reviewe

Genetic and environmental variation in educational attainment : an individual-based analysis of 28 twin cohorts

We investigated the heritability of educational attainment and how it differed between birth cohorts and cultural-geographic regions. A classical twin design was applied to pooled data from 28 cohorts representing 16 countries and including 193,518 twins with information on educational attainment at 25 years of age or older. Genetic factors explained the major part of individual differences in educational attainment (heritability: a(2)=0.43; 0.41-0.44), but also environmental variation shared by co-twins was substantial (c(2)=0.31; 0.30-0.33). The proportions of educational variation explained by genetic and shared environmental factors did not differ between Europe, North America and Australia, and East Asia. When restricted to twins 30 years or older to confirm finalized education, the heritability was higher in the older cohorts born in 1900-1949 (a(2)=0.44; 0.41-0.46) than in the later cohorts born in 1950-1989 (a(2)=0.38; 0.36-0.40), with a corresponding lower influence of common environmental factors (c(2)=0.31; 0.29-0.33 and c(2)=0.34; 0.32-0.36, respectively). In conclusion, both genetic and environmental factors shared by co-twins have an important influence on individual differences in educational attainment. The effect of genetic factors on educational attainment has decreased from the cohorts born before to those born after the 1950s.Peer reviewe