Spatial autocorrelation in biology 2. Some biological implications and four applications of evolutionary and ecological interest

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72158/1/j.1095-8312.1978.tb00014.x.pd

Spatial autocorrelation in biology 1. Methodology

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74811/1/j.1095-8312.1978.tb00013.x.pd

A Bayesian approach to wavelet-based modelling of discontinuous functions applied to inverse problems

Inverse problems are examples of regression with more unknowns than the amount of information in the data and hence constraints are imposed through prior information. The proposed method defines the underlying function as a wavelet approximation which is related to the data through a convolution. The wavelets provide a sparse and multi-resolution solution which can capture local behaviour in an adaptive way. Varied prior models are considered along with level-specific prior parameter estimation. Archaeological stratigraphy data are considered where vertical earth cores are analysed producing clear piecewise constant function estimates

Gear-Specific Population Demographics of Channel Catfish in a Large Midwestern River

Various gear types have been used to sample populations of channel catfish Ictalurus punctatus in lotic systems. However, these gears produce different population characteristics (i.e., recruitment, growth, and mortality). We compared the population demographics of channel catfish in the Wabash River, Indiana, sampled with baited 25- and 32-mm-bar mesh hoop nets and three-phase alternating current (AC) electrofishing. Based on catch per unit effort, the relative abundance of channel catfish sampled with 32-mm hoop nets was lower than that of fish sampled with 25-mm hoop nets and AC electrofishing. Each gear type also resulted in a different length frequency, mean length increasing progressively in sampling with 25-mm hoop nets, 32-mm hoop nets, and AC electrofishing. Similarly, age-frequency distributions differed among gears. The 25-mm hoop nets biased the age structure toward younger individuals (mean age = 2.5), whereas both 32-mm hoop nets (mean age = 4.0) and AC electrofishing (mean age = 5.8) included older fish. Catch-curve analysis generated different mortality rates for the three gear types, the mortality rate being highest (50%) in fish sampled with 25-mm hoop nets. Gear-specific size and age structures led to differences in von Bertalanffy statistics among the 25-mm hoop nets and AC electrofishing, while the results for 32-mm hoop nets were uninterpretable. Because the different gears led to conflicting parameter estimates, management practices based on sampling with single gears may be contradictory. Given the differences in gear selectivity, biologists need to approach management cautiously until calibration to the true size and age structure is conducted

Asymptotic Scaling in the Two-Dimensional O(3)O(3) σ\sigma-Model at Correlation Length 10510^5

We carry out a high-precision Monte Carlo simulation of the two-dimensional $O(3)$-invariant $\sigma$-model at correlation lengths $\xi$ up to $\sim 10^5$. Our work employs a new and powerful method for extrapolating finite-volume Monte Carlo data to infinite volume, based on finite-size-scaling theory. We discuss carefully the systematic and statistical errors in this extrapolation. We then compare the extrapolated data to the renormalization-group predictions. The deviation from asymptotic scaling, which is $\approx 25\%$ at $\xi \sim 10^2$, decreases to $\approx 4\%$ at $\xi \sim 10^5$.Comment: 11 pages including 3 figures, 278964 bytes Postscript (changed storage format

Mathematical Aspects of the Periodic Law

We review different studies of the Periodic Law and the set of chemical elements from a mathematical point of view. This discussion covers the first attempts made in the 19th century up to the present day. Mathematics employed to study the periodic system includes number theory, information theory, order theory, set theory and topology. Each theory used shows that it is possible to provide the Periodic Law with a mathematical structure. We also show that it is possible to study the chemical elements taking advantage of their phenomenological properties, and that it is not always necessary to reduce the concept of chemical elements to the quantum atomic concept to be able to find interpretations for the Periodic Law. Finally, a connection is noted between the lengths of the periods of the Periodic Law and the philosophical Pythagorean doctrine.Comment: 20 pages, PDF fil

A Differentiation-Based Phylogeny of Cancer Subtypes

Histopathological classification of human tumors relies in part on the degree of differentiation of the tumor sample. To date, there is no objective systematic method to categorize tumor subtypes by maturation. In this paper, we introduce a novel computational algorithm to rank tumor subtypes according to the dissimilarity of their gene expression from that of stem cells and fully differentiated tissue, and thereby construct a phylogenetic tree of cancer. We validate our methodology with expression data of leukemia, breast cancer and liposarcoma subtypes and then apply it to a broader group of sarcomas. This ranking of tumor subtypes resulting from the application of our methodology allows the identification of genes correlated with differentiation and may help to identify novel therapeutic targets. Our algorithm represents the first phylogeny-based tool to analyze the differentiation status of human tumors

Selective Breeding for a Behavioral Trait Changes Digit Ratio

The ratio of the length of the second digit (index finger) divided by the fourth digit (ring finger) tends to be lower in men than in women. This 2D∶4D digit ratio is often used as a proxy for prenatal androgen exposure in studies of human health and behavior. For example, 2D∶4D ratio is lower (i.e. more “masculinized”) in both men and women of greater physical fitness and/or sporting ability. Lab mice have also shown variation in 2D∶4D as a function of uterine environment, and mouse digit ratios seem also to correlate with behavioral traits, including daily activity levels. Selective breeding for increased rates of voluntary exercise (wheel running) in four lines of mice has caused correlated increases in aerobic exercise capacity, circulating corticosterone level, and predatory aggression. Here, we show that this selection regime has also increased 2D∶4D. This apparent “feminization” in mice is opposite to the relationship seen between 2D∶4D and physical fitness in human beings. The present results are difficult to reconcile with the notion that 2D∶4D is an effective proxy for prenatal androgen exposure; instead, it may more accurately reflect effects of glucocorticoids, or other factors that regulate any of many genes