Comparison of Chuvashes,Maris, and Russians with Respect to Vital Statistics and Crow's Index

Genetic demographic characteristics were calculated for Chuvash and Russian inhabitants of the Republic of Chuvashia. The generation lengths were 27.09 and 26.4 years and the sibship sizes were 2.54 and 1.82 for Chuvashes and Russians, respectively. Crow's indices and their components were as follows: I _m = 0.05, I _f = 0.31, and I _tot = 0.37 for Chuvashes and I _m = 0.03, I _f = 0.43, and I _tot = 0.46 for Russians. The genetic demographic characteristics obtained were compared with those for Highland and Meadow Maris.     

Comparative vital statistics along the pastoral nomadism-sedentarism continuum

Vital statistics on pastoral nomadic and sedentarizing nomadic societies are by-and-large non-existent. Such information is highly important for both academic and policy-making reasons as pastoral nomadism as a mode of life is disappearing. This paper attempts to gather and present as much information as possible on crude birth and death rates and natural increase rates for various pastoral nomadic societies in different African and Middle Eastern countries. The information is arranged by a subdivision into nomads, seminomads, and sedentarized nomads. A summarization of this information suggests a possible pattern by which birth rates rise, death rates fall (but may rise in certain circumstances), and natural increase rates rise along the nomadism-sedentarism continuum. Such a possible pattern has several policy implications for governments assessing the needs of a nomadic society undergoing a process of change in its socio-ecological relationships.This article was written while the author was a visiting scholar at the Department of Geography at the University of California. The author wishes to thank Nga and Allen Scott and Melanine M. Patton, as well as two anonymous referees, for their assistance and suggestions for this paper.     

The natural variability of vital rates and associated statistics

The first concern of this work is the development of approximations to the distributions of crude mortality rates, age-specific mortality rates, age-standardized rates, standardized mortality ratios, and the like for the case of a closed population or period study. It is found that assuming Poisson birthtimes and independent lifetimes implies that the number of deaths and the corresponding midyear population have a bivariate Poisson distribution. The Lexis diagram is seen to make direct use of the result. It is suggested that in a variety of cases, it will be satisfactory to approximate the distribution of the number of deaths given the population size, by a Poisson with mean proportional to the population size. It is further suggested that situations in which explanatory variables are present may be modelled via a doubly stochastic Poisson distribution for the number of deaths, with mean proportional to the population size and an exponential function of a linear combination of the explanatories. Such a model is fit to mortality data for Canadian females classified by age and year. A dynamic variant of the model is further fit to the time series of total female deaths alone by year. The models with extra-Poisson variation are found to lead to substantially improved fits.     

The relationship of climatological variables to selected vital statistics

Correlations were examined between 10 climatological variables and 8 types of death rate for the 143 largest Standard Metropolitan Statistical Areas in the USA. Most of the relationships could be attributed to population factors such as proportion of foreign stock and median age in the areas. The data support weather conditions as possible causal factors in fatal heart attacks and accidents only.     

Estimated life expectancy and risk of death from cancer by quartiles in the older Japanese population: 2010 vital statistics

Data on life expectancies and risk of death from cancer are essential information to have when making informed decisions about cancer screening and treatment options, but has never been presented in a way that is readily available to use for physicians in Japan. We provided estimates of life expectancies and predicted risk of death from seven most common types of cancer (lung, gastric, liver, colon, prostate, breast, and cervical) by quartiles for the older Japanese population above 50 years old, using 2010 life tables and cancer mortality statistics data. We found that there was a large difference in life expectancy between older persons in the upper and lower quartiles. Risk of death from breast cancer was low. By using this data, physicians can more accurately obtain life expectancy estimates by assessing which quartile the patient is most likely to fall under, and help patients make better informed decisions.     

The effect of skewed distributions of vital statistics on growth of age-structured populations

Given that the variance of vital statistics can influence population projections, it seems reasonable that positive skew as observed for the distribution of larval survivorship of spruce budworms might also have a significant effect on stochastic projections of population growth. Simulations of population growth, using variable survivorship for a single age class, demonstrate that shape of the distribution of survivorship influences the outcome of stochastic population growth, and therefore is important for evolutionary and ecological theory. Unfortunately, empirical distributions of survivorships or fecundities for single life history stages are rare in the current literature.     

Using statistics to design and estimate vital rates in matrix population models for a perennial herb

Matrix population models are widely used to assess population status and to inform management decisions. Despite existing theories for building such models, model construction is often partially based on expert opinion. So far, model structure has received relatively little attention, although it may affect estimates of population dynamics. Here, we assessed the consequences of two published matrix structures (a 4 × 4 matrix based on expert opinion and a 10 × 10 matrix based on statistical modeling) for estimates of vital rates and stochastic population dynamics of the long-lived herb Astragalus scaphoides. We explored the ways in which choice of model structure alters the accuracy (i.e., mean) and precision (i.e., variance) of predicted population dynamics. We found that model structure had a negligible effect on the accuracy and precision of vital rates and stochastic stage distribution. However, the 10 × 10 matrix produced lower estimates of stochastic population growth rates than the 4 × 4 matrix, and more accurately predicted the observed trends in population abundance for three out of four study populations. Moreover, estimates of realized variation in population growth rate due to fluctuations in population stage structure over time were occasionally sensitive to matrix structure, suggesting differential roles of transient dynamics. Our study indicates that statistical modeling for choosing categories in matrix models might be preferable over expert opinion to accurately predict population trends and can provide a more objective way for model construction when the biological knowledge of the species is limited.     

Comparison of responses to Mn deficiency between the UK wheat genotypes Maris Butler, Paragon and the Australian wheat genotype C8MM

Wheat grown in Mn-deficient soil has been widely observed to produce much reduced yields. Breeding for Mn-efficient wheat genotypes adapted to Mn-deficient soils would represent a long-term solution for wheat agronomy, To characterize the physiological basis of Mn efficiency in wheat genotypes would facilitate the breeding programs for producing Mn-efficient wheat. Using a solution culture and a soil culture system in the present study, a Mn-efficient UK wheat genotype Maris Butler and a Mn-inefficient UK wheat genotype Paragon have been compared with a Mn-efficient Australian wheat genotype C8MM in the responses to Mn deficiency In order to characterize the Mn efficiency in these wheat genotypes.Results showed that in solution culture, Marls Butler grown under Mn deficiency had 77% relative dry matter yield of control plants that were grown under Mn sufficiency, whereas C8MM and Paragon had 60% and 58% relative dry matter yield of their respective controls. Results from the soil culture demonstrated that relative dry matter yield remained high for Marie Butler and C8MM (53% and 56%, respectively), whereas the value for Paragon dropped to 33%. In terms of dry matter yield and photosynthetic efficiency, Mads Butler demonstrated Mn efficiency in both solution culture and soil culture, whereas C8MM showed Mn efficiency only In soil culture. Results also demonstrated that under Mn-depleted supply in soil, plants of C8MM had a significantly higher ability in Mn uptake, whereas plants of Marls Butler showed a higher internal Mn usa efficiency in comparison with plants of Paragon. Results from the present study indicate that the ability of C8MM to accumulate higher amounts of Mn is the basis of the improved Mn efficiency of this genotype in comparison with Paragon, and in Marls Butler there is a higher internal use of Mn expressed as an improved photosynthetic efficiency in conferring its Mn efficiency. It is suggested that more than one mechanism has arisen in wheat to confer tolerance to Mn deficiency.     

Functional region prediction with a set of appropriate homologous sequences-an index for sequence selection by integrating structure and sequence information with spatial statistics

ABSTRACT: BACKGROUND: The detection of conserved residue clusters on a protein structure is one of the effective strategies for the prediction of functional protein regions. Various methods, such as Evolutionary Trace, have been developed based on this strategy. In such approaches, the conserved residues are identified through comparisons of homologous amino acid sequences. Therefore, the selection of homologous sequences is a critical step. It is empirically known that a certain degree of sequence divergence in the set of homologous sequences is required for the identification of conserved residues. However, the development of a method to select homologous sequences appropriate for the identification of conserved residues has not been sufficiently addressed. An objective and general method to select appropriate homologous sequences is desired for the efficient prediction of functional regions. RESULTS: We have developed a novel index to select the sequences appropriate for the identification of conserved residues, and implemented the index within our method to predict the functional regions of a protein. The implementation of the index improved the performance of the functional region prediction. The index represents the degree of conserved residue clustering on the tertiary structure of the protein. For this purpose, the structure and sequence information were integrated within the index by the application of spatial statistics. Spatial statistics is a field of statistics in which not only the attributes but also the geometrical coordinates of the data are considered simultaneously. Higher degrees of clustering generate larger index scores. We adopted the set of homologous sequences with the highest indexscore, under the assumption that the best prediction accuracy is obtained when the degree of clustering is the maximum. The set of sequences selected by the index led to higher functional region prediction performance than the sets of sequences selected by other sequence-based methods. CONCLUSIONS: Appropriate homologous sequences are selected automatically and objectively by the index. Such sequence selection improved the performance of functional region prediction. As far as we know, this is the first approach in which spatial statistics have been applied t o protein analyses. Such integration of structure and sequence information would be useful for other bioinformatics problems.