Socioeconomic factors affecting first marriage and birth rates by sex and age in the total Japanese population.

The effects of a wide variety of social, economic and demographic factors on age-specific first marriage and live birth rates in 46 Japanese prefectures were analyzed using stepwise regression analysis for 1970 and again for 1975 after classification of those twenty-two factors by factor analysis. The principal results were as follows: (1) high employment (high income) and social mobility caused by industrialization had a strongly positive influence on the first marriage and birth rates for young females, (2) rural and urban residence factors had positive effects on the marriage and birth rates for young males and females, respectively, (3) old age factor had an inverse effect on the marriage rates for both males and females over a wide range of ages, and (4) young age factor promoted the birth rate for young and middle-aged females. The characteristics of the first marriage and live birth rates in Japan were discussed in the light of these findings.     

Socioeconomic factors affecting the longevity of the Japanese population: a study for 1980 and 1985.

The effects of urbanisation, low income and rejuvenation of the population on life expectancy at birth and at 20, 40 and 65 years of age for males and females in Japan were examined twice, in 1980 and 1985. For males, urbanisation was the major factor determining life expectancy at birth and at age 20 years, and low income was the key determinant of decreased life expectancy except at 65 years of age. For females high income was the factor significantly decreasing life expectancy at 65 years of age in 1980, and rejuvenation of the population inversely influenced life expectancy except at birth in 1985. Life expectancy for all age groups in 1985 was significantly longer than in 1980 for both males and females.     

The influence of larval density, food availability and habitat longevity on the life history and population growth rate of the midge Chironomus riparius

Despite long‐standing interest in the forms and mechanisms of density dependence, these are still imperfectly understood. However, in a constant environment an increase in density must reduce per capita resource availability, which in turn leads to reduced survival, fecundity and somatic growth rate. Here we report two population experiments examining the density dependent responses under controlled conditions of an important indicator species, Chironomus riparius. The first experiment was run for 35 weeks and was started at low density with replicate populations being fed three different rations. Increased ration reduced generation time and increased population growth rate (pgr) but had no effect on survival, fecundity and female body weight in the first generation. In the second generation there was a six‐fold increase in generation time, presumably due to the greatly reduced per capita resource availability as the estimated initial densities of the second generation were 300 times greater than the first. Juvenile survival to emergence, fecundity, adult body weight and pgr declined by 90%, 75%, 35% and 99%, respectively. These large between‐generation effects may have obscured the effects of the threefold variation in ration, as only survival to emergence significantly increased with ration in the second generation. These results suggest that some chironomid larvae survive a reduction in resource availability by growing more slowly. In the ephemeral habitats sometimes occupied by C. riparius, the effects of population density may depend crucially on the longevity of the environment. A second experiment was therefore performed to measure pgr from six different starting densities over an eight‐week period. The relationship between pgr and density was concave, viewed from above. At densities above 16 larvae per cm², less than 1% of the population emerged and no offspring were produced. Under the conditions of experiment 2 – an 8‐week habitat lifespan – carrying capacity was estimated as 8 larvae per cm².     

Mitochondrial whims: metabolic rate,longevity and the rate of molecular evolution

The evolutionary rate of mitochondrial DNA (mtDNA) is highly variable across lineages in animals, and particularly in mammals. This variation has been interpreted as reflecting variations in metabolic rate: mitochondrial respiratory activity would tend to generate mutagenic agents, thus increasing the mutation rate. Here we review recent evidence suggesting that a direct, mechanical effect of species metabolic rate on mtDNA evolutionary rate is unlikely. We suggest that natural selection could act to reduce the (somatic) mtDNA mutation rate in long-lived species, in agreement with the mitochondrial theory of ageing.     

Cultural and environmental factors affecting the longevity of Escherichia coli in Histosols.

The survival of Escherichia coli in organic soils (Histosols) was examined. The death rate of this organism in Pahokee muck was less than that observed in Pompano fine sand. The number of viable E. coli cells found in the muck was approximately threefold greater than that found in the sand following 8 days of incubation. The initial population of the coliform affected the death rate. The rate of loss of viability varied 100-fold when the population size decreased from 2.5 x 10(7) to 3.4 x 10(4). Other factors affecting the viability of E. coli in muck were aerobic versus anaerobic growth of the organism and moist versus flooded conditions in the soil. The greatest survival of the coliform was noted with anaerobically grown cells amended to flooded soil. That the observed decrease in E. coli viability in soil was the result of biotic factors was demonstrated with amendment of sterile soil with E. coli. When 1.1 x 10(5) bacteria per g of soil were added to sterile muck, a population of 3.0 x 10(7) organisms per g of soil developed over a 10-day period. The role of the protozoa in eradication of the coliform from the muck was indicated by a sixfold increase in the protozoan population in natural soil amended with E. coli. Higher organic matter content in a Histosol compared with a mineral soil resulted in an increased survival of the fecal coliforms. Biotic factors are instrumental in the decline in coliform populations, but the potential for growth of the coliform in the organic soil could extend the survival of the organism.     

Elective total hip replacement: incidence,emergency readmission rate,and postoperative mortality.

OBJECTIVES--To report the incidence of elective total hip replacement and postoperative mortality, emergency readmission rates, and the demographic factors associated with these rates in a large defined population. DESIGN--Analysis of linked, routine abstracts of hospital inpatient records and death certificates. SETTING--10 hospitals in six districts in Oxford Regional Health Authority covered by the Oxford record linkage study. SUBJECTS--Records for 11,607 total hip replacements performed electively in 1976-85. MAIN OUTCOME MEASURES--Incidence of operation, postoperative mortality, relative mortality ratios, and incidence of emergency readmission. RESULTS--NHS operation rates increased over time from 43 to 58 operations/100,000 population. Variation in operation rates between districts reduced over time. Operation rates were on average 25% higher in women than men. There were 93 deaths (11/1000 operations) within 90 days of the operation and 208 emergency readmissions (28/1000 operations) within 28 days of discharge. Postoperative mortality and emergency readmission rates increased with age. No significant trend with time was found. Mortality in the 90 days after the operation was 2.5-fold higher (1.9 to 3.0) than in the rest of the first postoperative year. This represented an estimated excess of 6.5 (4.2 to 8.8) early postoperative deaths/1000 operations. Most deaths were ascribed to cardiovascular events. Thromboembolic disease was the commonest reason for emergency readmission. CONCLUSIONS--The pronounced increase in operations in districts with initially low rates suggests a trend towards greater equity in the local provision of NHS hip arthroplasty. The early postoperative clusters of deaths attributed to cardiovascular disease and of readmissions for thromboembolic disease suggest that there is scope for investigating ways of reducing the incidence of major adverse postoperative events.     

The correlation of the indices of animal longevity and mortality in stationary populations with a constant rate of mortality

Equations have been derived on the basis of general ratios of the numbers of different age groups of animals that allow to estimate the mortality coefficient in populations with stationary age structure and intensity of mortality that does not depend on age at their continuous and discontinuous replenishing by frequency of occurrence of individuals of the maximal age. The proposed method of estimation of mortality has been tested on models with different numbers of animals and age classes. The equation gives a non-biased estimate of mortality coefficient for populations with discontinuous replenishing with young individuals at very small sample sizes (less than 10 individuals).     

Birth-weight-specific infant and neonatal mortality: effects of heterogeneity in the birth cohort

Birth-weight-specific infant mortality is examined using a novel statistical procedure, parametric mixtures of logistic regressions. The results indicate that birth cohorts are composed of two or more subpopulations that are heterogeneous with respect to infant mortality. One subpopulation appears to account for the "normal" process of fetal development, while the other, which accounts for the majority of births at both low and high birth weights, may represent fetuses that were "disturbed" during development. Surprisingly, estimates of neonatal and infant mortality indicate that the "disturbed" subpopulation has lower birth-weight-specific mortality, although overall crude mortality rates are higher for this subpopulation. It is hypothesized that this is due to high rates of fetal loss among the "disturbed" subpopulation, resulting in a highly selected group at birth. The heterogeneity identified in the birth cohort could be responsible for recent decelerations in the decline in infant mortality, and might be the cause of unexplained ethnic differences in birth-weight-specific infant mortality. The novel statistical methodology developed here has broad application within human biology. In particular, it could be used in any context where parametric mixture modeling is applied, such as complex segregation analysis.     

Sex determination,longevity, and the birth and death of reptilian species

Vertebrate sex‐determining mechanisms (SDMs) are triggered by the genotype (GSD), by temperature (TSD), or occasionally, by both. The causes and consequences of SDM diversity remain enigmatic. Theory predicts SDM effects on species diversification, and life‐span effects on SDM evolutionary turnover. Yet, evidence is conflicting in clades with labile SDMs, such as reptiles. Here, we investigate whether SDM is associated with diversification in turtles and lizards, and whether alterative factors, such as lifespan's effect on transition rates, could explain the relative prevalence of SDMs in turtles and lizards (including and excluding snakes). We assembled a comprehensive dataset of SDM states for squamates and turtles and leveraged large phylogenies for these two groups. We found no evidence that SDMs affect turtle, squamate, or lizard diversification. However, SDM transition rates differ between groups. In lizards TSD‐to‐GSD surpass GSD‐to‐TSD transitions, explaining the predominance of GSD lizards in nature. SDM transitions are fewer in turtles and the rates are similar to each other (TSD‐to‐GSD equals GSD‐to‐TSD), which, coupled with TSD ancestry, could explain TSD's predominance in turtles. These contrasting patterns can be explained by differences in life history. Namely, our data support the notion that in general, shorter lizard lifespan renders TSD detrimental favoring GSD evolution in squamates, whereas turtle longevity permits TSD retention. Thus, based on the macro‐evolutionary evidence we uncovered, we hypothesize that turtles and lizards followed different evolutionary trajectories with respect to SDM, likely mediated by differences in lifespan. Combined, our findings revealed a complex evolutionary interplay between SDMs and life histories that warrants further research that should make use of expanded datasets on unexamined taxa to enable more conclusive analyses.     

Ecological and environmental effects of land use change in rapid urbanization: The case of hangzhou,China

Land use changes sharply under rapid urbanization, yet its ecological and environmental effects are often neglected in land use decisions. Using the case of Hangzhou, China, we analyze the ecological and environmental effects of land use changes, including ecosystem services value (ESV) and carbon emissions, based on Landsat TM images from 1995, 2000, 2005, 2010, and 2014. We found significant ecological and environmental effects of land use changes under rapid urbanization. The value of ecosystem services in Hangzhou decreased from 546.7 million USD in 1995 to 448.97 million USD in 2014, and the ratio of ESV to GDP decreased from 5.8% to 0.6%. The net carbon emissions associated with land use changes increased from 4.26 million tons in 1995 to 15.10 million tons in 2014, mainly due to the increase of built-up land carbon emissions and the decrease of forest land carbon sink. The ESV is unevenly distributed spatially and low ESV spread from the central to the peripheral area. We use scenario analysis to illustrate that economic growth and environmental protection could be coordinated by bringing ecological and environmental effects into land use decisions.     

The interactive effects of climate, life history, and interspecific neighbours on mortality in a population of seed harvester ants

Abstract.  1. Fifteen years of census data from a population of the red harvester ant ( Pogonomyrmex barbatus ), 5 years of census data from populations of Aphaenogaster cockerelli and Myrmecocystus mimicus at the same site, and long-term precipitation data from a nearby weather station were used to examine how nearest interspecific neighbours, climate, and life history influence P. barbatus colony mortality.
2. It was found that more P. barbatus colonies die following dry summers than following wet summers, but there is no relationship between the establishment of new colonies and rainfall.
3.  Aphaenogaster cockerelli , but not M. mimicus , nearest neighbours influence P. barbatus colony mortality in some years and for some ages.
4. The effects of nearest A. cockerelli neighbours are usually most severe following dry summers, when resource availability is reduced.     

Influence of month and climatic factors on the period of birth,litter size,birth weight and preweaning mortality of sheep in Ghana

Relationships between month and clinatic factors-rainfall, ambient temperature, relative humidity (RH) and temperature-humidity index (THI)-with time of parturition, litter size, birth weight and preweaning mortality were studied in Djallonke and Dja lonke x Sahelian sheep. Births (4142) occurred all year round although there were significant differences in the number of births per month. Maximum litter size did not coincide with the maximum births. Peak conceptions occurred in the early parts of the major rainy season. There were also significant differences in birth weights and mortalities (%) per month. Maximum and minimum values (of birth weighs and mortalities) occurred in the latter part of the rainy seasons and dry periods respectively. There were significant positive correlations between litter size and cumulative rainfall in the 4th–6th months periods prior to lambing. Birth weights of both males and females were positively and significantly associated with minimum temperature and cumulative rain-fall in the 2- and 3-months period prior to lambing respectively. There were significant positive correlations between mortality and minimum and maximum RH and cumulative rainfall in the 3 months after lambing.     

Management factors affecting mortality,feed intake and feed conversion ratio of grow-finishing pigs

The aim of this study was to determine the effect of animal management and farm facilities on total feed intake (TFI), feed conversion ratio (FCR) and mortality rate (MORT) of grower-finishing pigs. In total, 310 batches from 244 grower-finishing farms, consisting of 454 855 Pietrain sired pigs in six Spanish pig companies were used. Data collection consisted of a survey on management practices (season of placement, split-sex by pens, number of pig origins, water source in the farm, initial or final BW) and facilities (floor, feeder, ventilation or number of animals placed) during 2008 and 2009. Results indicated that batches of pigs placed between January and March had higher TFI (P=0.006), FCR (P=0.005) and MORT (P=0.03) than those placed between July and September. Moreover, batches of pigs placed between April and June had lower MORT (P=0.003) than those placed between January and March. Batches which had split-sex pens had lower TFI (P=0.001) and better FCR (P<0.001) than those with mixed-sex in pens; pigs fed with a single-space feeder with incorporated drinker also had the lowest TFI (P<0.001) and best FCR (P<0.001) in comparison to single and multi-space feeders without a drinker. Pigs placed in pens with <50% slatted floors presented an improvement in FCR (P<0.05) than pens with 50% or more slatted floors. Batches filled with pigs from multiple origins had higher MORT (P<0.001) than those from a single origin. Pigs housed in barns that performed manual ventilation control presented higher MORT (P<0.001) in comparison to automatic ventilation. The regression analysis also indicated that pigs which entered to grower-finisher facilities with higher initial BW had lower MORT (P<0.05) and finally pigs which were sent to slaughterhouse with a higher final BW presented higher TFI (P<0.001). The variables selected for each dependent variable explained 61.9%, 24.8% and 20.4% of the total variability for TFI, FCR and MORT, respectively. This study indicates that farms can increase growth performance and reduce mortality by improving farm facilities and/or modifying management practices.     

The effect of urbanization on ant abundance and diversity: a temporal examination of factors affecting biodiversity

Numerous studies have examined the effect of urbanization on species richness and most studies implicate urbanization as the major cause of biodiversity loss. However, no study has identified an explicit connection between urbanization and biodiversity loss as the impact of urbanization is typically inferred indirectly by comparing species diversity along urban-rural gradients at a single time point. A different approach is to focus on the temporal rather than the spatial aspect and perform "before and after" studies where species diversity is cataloged over time in the same sites. The current study examined changes in ant abundance and diversity associated with the conversion of natural habitats into urban habitats. Ant abundance and diversity were tracked in forested sites that became urbanized through construction and were examined at 3 time points - before, during, and after construction. On average, 4.3±1.2 unique species were detected in undisturbed plots prior to construction. Ant diversity decreased to 0.7±0.8 species in plots undergoing construction and 1.5±1.1 species in plots 1 year after construction was completed. With regard to species richness, urbanization resulted in the permanent loss of 17 of the 20 species initially present in the study plots. Recovery was slow and only 3 species were present right after construction was completed and 4 species were present 1 year after construction was completed. The second objective examined ant fauna recovery in developed residential lots based on time since construction, neighboring habitat quality, pesticide inputs, and the presence of invasive ants. Ant diversity was positively correlated with factors that promoted ecological recovery and negatively correlated with factors that promoted ecological degradation. Taken together, these results address a critical gap in our knowledge by characterizing the short- and long-term the effects of urbanization on the loss of ant biodiversity.