University of Stirling

About: University of Stirling is a education organization based out in Stirling, Stirling, United Kingdom. It is known for research contribution in the topics: Population & Polyunsaturated fatty acid. The organization has 7722 authors who have published 20549 publications receiving 732940 citations. The organization is also known as: Stirling University.

Social structure and life-history patterns in western gorillas (Gorilla gorilla gorilla).

Abstract: Life-history traits and ecological conditions have an important influence on primate social systems. Most of what we know about the life-history patterns and social structure of gorillas comes from studies of eastern gorillas (Gorilla beringei sp.), which live under dramatically different ecological conditions compared to western gorillas (Gorilla gorilla sp.). In this paper we present new data on western gorilla social structure and life histories from four study sites, and make comparisons with eastern gorilla populations. Data were obtained from two study sites with gorilla groups undergoing the habituation process (Lossi, Democratic Republic of Congo and Bai Hokou, Central African Republic) and two "bai" studies (Maya Nord and Mbeli Bai, Republic of Congo). The size and structure of these groups were similar to those seen in eastern gorillas. However, differences in the occurrence of various group transitions (group formations, changes between one-male and multimale composition, and group disintegrations) exist, and western gorillas notably exhibit much higher rates of male emigration and correspondingly fewer multimale groups compared to mountain gorillas. Certain phenomena have been observed only rarely, including predation by leopards. The preliminary data show no significant differences in birth rates between western gorillas and mountain gorillas. The ecological variability across gorilla habitats likely explains the flexibility in the social system of gorillas, but we need more information on the social relationships and ecology of western gorillas to elucidate the causes for the similarities and differences between western and eastern gorillas on the levels of individuals, social groups, and population dynamics.

A high quality assembly of the Nile Tilapia ( Oreochromis niloticus ) genome reveals the structure of two sex determination regions

Abstract: Tilapias are the second most farmed fishes in the world and a sustainable source of food. Like many other fish, tilapias are sexually dimorphic and sex is a commercially important trait in these fish. In this study, we developed a significantly improved assembly of the tilapia genome using the latest genome sequencing methods and show how it improves the characterization of two sex determination regions in two tilapia species. A homozygous clonal XX female Nile tilapia (Oreochromis niloticus) was sequenced to 44X coverage using Pacific Biosciences (PacBio) SMRT sequencing. Dozens of candidate de novo assemblies were generated and an optimal assembly (contig NG50 of 3.3Mbp) was selected using principal component analysis of likelihood scores calculated from several paired-end sequencing libraries. Comparison of the new assembly to the previous O. niloticus genome assembly reveals that recently duplicated portions of the genome are now well represented. The overall number of genes in the new assembly increased by 27.3%, including a 67% increase in pseudogenes. The new tilapia genome assembly correctly represents two recent vasa gene duplication events that have been verified with BAC sequencing. At total of 146Mbp of additional transposable element sequence are now assembled, a large proportion of which are recent insertions. Large centromeric satellite repeats are assembled and annotated in cichlid fish for the first time. Finally, the new assembly identifies the long-range structure of both a ~9Mbp XY sex determination region on LG1 in O. niloticus, and a ~50Mbp WZ sex determination region on LG3 in the related species O. aureus. This study highlights the use of long read sequencing to correctly assemble recent duplications and to characterize repeat-filled regions of the genome. The study serves as an example of the need for high quality genome assemblies and provides a framework for identifying sex determining genes in tilapia and related fish species.

Relationship between Prostate Specific Antigen, Prostate Volume and Age in the Benign Prostate

Abstract: Summary— The relationship between prostate specific antigen (PSA) levels, prostate volume and age was examined in 472 men who underwent PSA assay (Hybritech), digital rectal examination (D RE) and transrectal ultrasound (TRUS) as part of a community survey of benign prostatic hyperplasia following exclusion of men with prostate cancer. The mean age of the study population was 60 years (range 40–79). The mean PSA was 2.4 ng/ml and 85% of the men had levels <4 ng/ml. There was a modest correlation between PSA and both age and prostate volume. The mean prostate and adenoma volumes were 32 ml (SD 13.4) and 15 ml (SD 10.7) respectively. Prostate volume increased with age. Linear regression analysis revealed an independent association between PSA and age when controlling for volume. The mean ratio of PSA per unit of prostate volume was 0.072 ng/ml. This ratio also increased with age. Age and prostate volume influences PSA levels independently. The sensitivity and specificity of PSA adjusted for volume and age in the diagnosis of prostate cancer need to be evaluated in association with DRE and TRUS.

Nest building by lowland gorillas in the Lopé Reserve, Gabon: Environmental influences and implications for censusing

Abstract: We analyzed data from 373 fresh nest-sites (containing 2435 nests) of lowland gorillas (Gorilla g. gorilla)during a 4-year period in the Lope Reserve, Gabon, to determine whether the observed variability in nest building was due to environmental influences. We recognized and defined seven types of nest in terms of the degree of construction and the raw materials used. Overall, nests built on the ground from herbaceous plants are the most common type (40%), followed by tree nests (35%). Frequencies of the different nest-types vary significantly between eight habitat-types. In habitat-types with high densities of understory herbs, ground nests predominated, but when herbs were rare, the majority of nests were in trees. A general preference for sleeping in herbaceous ground nests is indicated since trees are abundant in all habitat-types, except savanna. The frequency of nesting in trees shows a significant positive correlation with rainfall, but effects of climate are confounded by seasonal variation in use of different habitat-types. When elephants were attracted to the same localized food sources as gorillas, many tree nests were built even when herbs were available. We conclude that different nest-types reflect a variety of solutions to maximize comfort, depending on available raw materials and the probability of rainfall or disturbance by elephants or both factors. Nests are a powerful tool for population censuses and demographic studies of great apes, but problems exist in interpreting data on lowland gorilla nests. Results from this analysis show that only a third of nest-sites accurately reflects group size (of weaned individuals) and that 26% of all gorilla nest-sites could be mistaken for those of chimpanzees, as all nests, or all those visible from a transect, were in trees. Gorilla nests at Lope were nonrandomly distributed with respect to habitat-types, and nest construction varied seasonally, thereby introducing sources of bias to transect nest counts. We discuss these problems and ones related to assessing the decay rate of nest-sites and make recommendations relevant to census work.