Glaciers caused zooplankton mortality?

Dead zooplankton were found in grab samples collected in Kongsfjorden(79N, Svalbard archipelago) in summer of 1995 and 1996. Theconcentration of dead plankters reached over 500 individualsof copepods and 130 individuals of Themicto per square metre.The biomass of dead zooplank ton reached 0.17 g C m^–2locally, and was not correlated with the depth of the locality,nor with the surface salinity. The bulk of sedimented planktonwas, however, found behind the sill of the inner fjord basin.We assume that massive discharge of glacial waters in summercauses mass mortality of surface zooplankton, which drift awayand sink in the innerfjord pool, thus supplying benthic communitieswith organic carbon.     

Is avian mortality preprogrammed?

The recent development of life history theory has led to an upsurge of interest in species-specific mortality patterns. Some recent findings on the geographic variation of avian mortality may help to bring more sharply into focus some fundamental issues of ageing (senescence). To say that a bird 'ages' is tantamount to saying that its likelihood of dying increases with age. To what extent are species life spans preprogrammed, to what extent are they the chance product of environmental hazards, and how do these factors interact with each other?     

Is hunting mortality additive or compensatory to natural mortality? Effects of experimental harvest on the survival and cause-specific mortality of willow ptarmigan

1. The effects of harvest on the annual and seasonal survival of willow ptarmigan Lagopus lagopus L. were tested in a large-scale harvest experiment. Management units were randomly assigned to one of three experimental treatments: 0%, 15% or 30% harvest. Seasonal quotas were based on the experimental treatment and estimates of bird density before the hunting season. Survival rates and hazard functions for radio-marked ptarmigan were then estimated under the competing risks of harvest and natural mortality. 2. The partially compensatory mortality hypothesis was supported: annual survival of ptarmigan was 0·54 ± 0·08 SE under 0% harvest, 0·47 ± 0·06 under 15% harvest, and was reduced to 0·30 ± 0·05 under 30% harvest. Harvest mortality increased linearly from 0·08 ± 0·05, 0·27 ± 0·05 and 0·42 ± 0·06 from 0% to 30% harvest, whereas natural mortality was 0·38 ± 0·08, 0·25 ± 0·05 and 0·28 ± 0·06 under the same treatments. 3. Realized risk of harvest mortality was 0·08-0·12 points higher than our set harvest treatments of 0-30% because birds were exposed to risk if they moved out of protected areas. The superadditive hypothesis was supported because birds in the 30% harvest treatment had higher natural mortality during winter after the hunting season. 4. Natural mortality was mainly because of raptor predation, with two seasonal peaks in fall and spring. Natural and harvest mortality coincided during early autumn with little potential for compensation during winter months. Peak risk of harvest mortality was 5× higher than natural mortality. Low natural mortality during winter suggests that most late season harvest would be additive mortality. 5. Environmental correlates of natural mortality of ptarmigan included seasonal changes in snow cover, onset of juvenile dispersal, and periods of territorial activity. Natural mortality of ptarmigan was highest during autumn movements and nesting by gyrfalcons Falco rusticolus L. Mortality was low when gyrfalcons had departed for coastal wintering sites, and during summer when ptarmigan were attending nests and broods. 6. Our experimental results have important implications for harvest management of upland gamebirds. Seasonal quotas based on proportional harvest were effective and should be set at ≤ 15% of August populations for regional management plans. Under threshold harvest of a reproductive surplus, 15% harvest would be sustainable at productivity rates ≥ 2·5 young per pair. Impacts of winter harvest could be minimized by closing the hunting season in early November or by reducing late season quotas.     

Genetic determinants of mortality. Can findings from genome-wide association studies explain variation in human mortality?

Twin studies have estimated the heritability of longevity to be approximately 20–30 %. Genome-wide association studies (GWAS) have revealed a large number of determinants of morbidity, but so far, no new polymorphisms have been discovered to be associated with longevity per se in GWAS. We aim to determine whether the genetic architecture of mortality can be explained by single nucleotide polymorphisms (SNPs) associated with common traits and diseases related to mortality. By extensive quality control of published GWAS we created a genetic score from 707 common SNPs associated with 125 diseases or risk factors related with overall mortality. We prospectively studied the association of the genetic score with: (1) time-to-death; (2) incidence of the first of nine major diseases (coronary heart disease, stroke, heart failure, diabetes, dementia, lung, breast, colon and prostate cancers) in two population-based cohorts of Dutch and Swedish individuals (N = 15,039; age range 47–99 years). During a median follow-up of 6.3 years (max 22.2 years), we observed 4,318 deaths and 2,132 incident disease events. The genetic score was significantly associated with time-to-death [hazard ratio (HR) per added risk allele = 1.003, P value = 0.006; HR 4th vs. 1st quartile = 1.103]. The association between the genetic score and incidence of major diseases was stronger (HR per added risk allele = 1.004, P value = 0.002; HR 4th vs. 1st quartile = 1.160). Associations were stronger for individuals dying at older ages. Our findings are compatible with the view of mortality as a complex and highly polygenetic trait, not easily explainable by common genetic variants related to diseases and physiological traits.     

Do well-connected landscapes promote road-related mortality?

Cost surface (CS) models have emerged as a useful tool to examine the interactions between landscapes patterns and wildlife at large-scale extents. This approach is particularly relevant to guide conservation planning for species that show vulnerability to road networks in human-dominated landscapes. In this study, we measured the functional connectivity of the landscape in southern Portugal and examined how it may be related to stone marten road mortality risk. We addressed three questions: (1) How different levels of landscape connectivity influence stone marten occurrence in montado patches? (2) Is there any relation between montado patches connectivity and stone marten road mortality risk? (3) If so, which road-related features might be responsible for the species’ high road mortality? We developed a series of connectivity models using CS scenarios with different resistance values given to each vegetation cover type to reflect different resistance to species movement. Our models showed that the likelihood of occurrence of stone marten decreased with distance to source areas, meaning continuous montado. Open areas and riparian areas within open area matrices entailed increased costs. We found higher stone marten mortality on roads in well-connected areas. Road sinuosity was an important factor influencing the mortality in those areas. This result challenges the way that connectivity and its relation to mortality has been generally regarded. Clearly, landscape connectivity and road-related mortality are not independent.     

Are low cholesterol values associated with excess mortality?

The relation between cholesterol concentration and mortality was studied prospectively over 17 years in 630 New Zealand Maoris aged 25-74. The dead or alive state of each person was determined in 1981. The causes of death were divided into three categories: cancer, cardiovascular disease, and "other." Using univariate and both linear and non-linear multivariate methods of analysis for survivorship data, significant inverse relations with serum cholesterol were found for total mortality in women, for mortality from cancer in men and women, and for other causes of mortality in both men and women. The inverse and non-linear association with total mortality in women remained significant when deaths in the first five years of follow up were excluded. This suggests that the association was not explained by undetected illness causing low cholesterol concentrations at the time of initial examination.     

Why fly? The possible benefits for lower mortality

In adult endotherms—birds and mammals—mortality rates are lower in flying than non-flying species. Rates vary with size, but allowing for this they are higher in penguins than flying birds, and in rodents than bats. These observations are most simply explained in terms of predation since flight, allowing movement in three dimensions, increases the chances of escape.
There are various problems in obtaining and comparing data on rates of mortality and this partly explains a wide scattering of points. Nevertheless the main results are statistically significant, mostly at P<0.001. Amongst birds, there are several other significant differences. Mortality rates are lower at lower latitudes, and in aquatic compared to terrestrial species, with cliff-nesters having lower rates than other aquatic birds and co-operative breeders than other terrestrial ones. No latitudinal effect was detected in mammals. The exceptionally low rates of mortality in bats and swifts are attributed to their being particularly hard to catch.     

Can road mortality limit populations of pool-breeding amphibians?

We integrated road maps, traffic volume data, and pool locations in a modeling study to estimate the potential effects of road mortality on populations of pool-breeding spotted salamanders (Ambystoma maculatum Shaw). Population projections based on spotted salamander life tables imply that an annual risk of road mortality for adults of >10% can lead to local population extirpation; mitigation efforts (tunnels, road closures, and other measures) should seek to reduce road mortality rates to below this threshold. For central and western Massachusetts, we estimated that salamanders would be exposed to at least this threshold level of risk at 22–73% of populations (assuming a 100 vs. 500 m migration distance, respectively). We conclude that road mortality can be a significant source of additive mortality for individual spotted salamanders in many parts of the species’ range. Efforts to prevent such mortality by transportation planners are likely warranted strictly on a biological basis in areas with road densities >2.5 km per km² of landscape and traffic volumes >250 vehicles/lane/day within the migration range of a breeding population of spotted salamanders.     

Natural-trap ursid mortality and the Kurtén Response

Ursid mortality data have long been used to evaluate associations between cave-bear remains (Ursus deningeri and U. spelaeus) and hominin (Homo sp.) remains. Typically, such ursid assemblages produce mortality patterns that indicate that juvenile and old bears died during hibernation, a pattern that is used to suggest that humans and bears occupied the same caves at different times. However, a different kind of mortality pattern can also be used to suggest human influence on cave bears, particularly under circumstances when bears and humans compete for habitat. In particular, data from Lawson Cave and Jerry Long Cave, Missouri indicate that young-adult North American black bears (Ursus americanus) are prone to capture in natural-trap caves. Similar faunal data from Sima de los Huesos in Spain, where cave-bear and hominin remains are found in the same deposit, might also suggest that the bears died from falling into a natural trap. It is concluded that mortality analysis of ursid remains from caves is a useful tool with which to evaluate accumulation histories of cave deposits and relations between humans, artifacts, and cave-bear remains. In particular, ursid mortality data are relevant to the Kurtén Response, a hypothesis reiterated in the recent literature that implicates human encroachment on ursid habitat (e.g., cave den sites) as a potential cause in cave-bear extinction.     

Predators and parasites of temporary row crop pests: Agents of irreplaceable mortality or scavengers acting prior to other mortality factors?

A study was conducted with the cabbage looper,Trichoplusia ni (Hübner), to determine: 1) whether naturally occurring entomophagous arthropods impart irreplaceable mortality to the cabbage looper in celery, and 2) whether entomophagous arthropods are present to impart such mortality toT. ni eggs and 1st instar larvae when the crop is sensitive to the pest. Predator evaluation involved 1) insecticidal + cage exclusion, 2) insecticidal exclusion alone, 3) D-vac removal of predators, and 4) sticky barrier exclusion. In all the exclusion regimes survival of eggs and larvae was higher than in the unexcluded control. Analysis of life table data was consistent with the hypothesis that some mortality of eggs due to parasitism byTrichogramma and of medium-larvae by other hymenopterous parasites was not replaceable by other mortality factors. The time of appearance of the first marketable petiole was correlated with both the height of the tallest petiole and the number of petioles on the plant. Peak densities ofTrichogramma and important predators occurred before the first marketable petiole appeared and declined to low levels as harvest approached.     

Cancer mortality 1981–2016 and contribution of specific cancers to current socioeconomic inequalities in all cancer mortality: A population-based study

BackgroundIn many high-income countries cancer mortality rates have declined, however, socioeconomic inequalities in cancer mortality have widened over time with those in the most deprived areas bearing the greatest burden. Less is known about the contribution of specific cancers to inequalities in total cancer mortality.MethodsUsing high-quality routinely collected population and mortality records we examine long-term trends in cancer mortality rates in Scotland by age group, sex, and area deprivation. We use the decomposed slope and relative indices of inequality to identify the specific cancers that contribute most to absolute and relative inequalities, respectively, in total cancer mortality.ResultsCancer mortality rates fell by 24 % for males and 10 % for females over the last 35 years; declining across all age groups except females aged 75+ where rates rose by 14 %. Lung cancer remains the most common cause of cancer death. Mortality rates of lung cancer have more than halved for males since 1981, while rates among females have almost doubled over the same period.ConclusionCurrent relative inequalities in total cancer mortality are dominated by inequalities in lung cancer mortality, but with contributions from other cancer sites including liver, and head and neck (males); and breast (females), stomach and cervical (younger females). An understanding of which cancer sites contribute most to inequalities in total cancer mortality is crucial for improving cancer health and care, and for reducing preventable cancer deaths.     

Does the decline in child injury mortality vary by social class? A comparison of class specific mortality in 1981 and 1991.

OBJECTIVE: To examine whether the decline in child injury death rates between 1981 and 1991 varied by social class. DESIGN: Comparison of class specific child injury death rates for 1979, 1980, 1982, and 1983, with those for the four years 1989-92. SETTING: England and Wales. SUBJECTS: Children aged 0-15 years. MAIN OUTCOME MEASURES: Death rates from injury and poisoning. RESULTS: Death rates from injury and poisoning have fallen for children in all social classes. The decline for children in social classes IV and V (21% and 2% respectively), however, is smaller than that for children in social classes I and II (32% and 37%). As a result of the differential decline in injury death rates, socioeconomic mortality differentials have increased. In the four years 1979-80 and 1982-83 the injury death rate for children in social class V was 3.5 times that of children in social class I. For the four years 1989-92 the injury death rate for children in social class V was 5.0 times that of children in social class I. Poisson regression modelling showed that the trend in the decline in death rates across the social classes was unlikely to have arisen by chance alone. CONCLUSIONS: Socioeconomic inequalities in child injury death rates have increased. If these gradients persist, the Health of the Nation''s target is likely to be met for children in the non-manual social classes but not for those in the manual social classes.     

Trends in regional cancer mortality in Taiwan 1992–2014

BackgroundAlthough the cancer mortality rate in Taiwan has been declining in recent years, no study has yet reported any regional differences in cancer mortality rates in Taiwan. We hypothesized that regional cancer mortality rates in Taiwan, an ethnically homogeneous society, exhibited no significant variations.MethodsWe investigated the trends in Taiwan regional cancer mortality between 1992 and 2014. We analyzed regional age-standardized cancer mortality rates for lung, liver, colon, stomach, oral, breast, and prostate cancers using the Taiwan Longitudinal Health Insurance Database and Demographic Database. Furthermore, we applied Joinpoint regression analysis to evaluate the trends across different regions.ResultsThere are clear regional variations in mortality rates for liver, stomach, and oral cancers, but not for lung, colon, breast, and prostate cancers. The regional death rates of oral cancer, especially for eastern Taiwan, not only elevate the fastest (APC = 14.78% per year, P < 0.001) but also show the largest disparities between men and women. Regional death rates for stomach cancer, which declined most rapidly, are converging in both general and gender groups. Liver cancer is the only one with regional variations whose trends do not all go in the same direction. We also demonstrated that northern Taiwan has significant regional advantages with respect to cancer mortality.ConclusionsSome but not all cancers in Taiwan show regional disparities. Liver, stomach, and oral cancers in Taiwan exhibit clear regional variations in mortality rates. In particular, the regional variations in oral cancer mortality rates are consistent with those in alcohol consumption.     

Malnutrition and child mortality: are socioeconomic factors important?

The influences of household economic condition, maternal education, sex, and nutritional status of children on mortality were examined using multivariate analytical techniques. Weights of around 1700 children aged 2 60 months in five villages of Matlab, Bangladesh, were taken during the first half of 1981. The children were followed for 18 months and their survival was recorded. The severely malnourished children had a risk of death nine times that of their counterparts with better nutritional status. Female children had a higher risk of death than the males. Mother's education and economic condition of household also showed negative relationships with the risk of death, but the effect of mother's education was modified by economic condition and sex of the children.     

Changes in Jewish mortality and survival, 1963–1987

Abstract

From information on mortality of Jews obtained from individual death certificates and population data from surveys of the Jewish population undertaken in 1963 and 1987, age‐specific death rates and life expectancy of the Jewish population of Rhode Island are compared with those of the total white population for 1963 and 1987 to assess changing differentials. The Jewish mortality experience continues to differ from that of the larger population even while both groups have experienced noticeable improvements. For males, the age standardized rates have widened in favor of Jews as have the life expectancies at birth and the percentage surviving to old age. By contrast, for females, the standardized death rate has widened considerably in favor of whites, while life expectancy has improved almost identically for both groups and therefore remained about equal, as it was in 1963. Reasons for these patterns are explored through attention to differences between Jews and the general white population in death rates at particular stages of the life cycle. Jews tend to be more advantaged at all but the most advanced ages, age groups in which proportionally more of the Jewish population and Jewish deaths are concentrated.     

Does female mortality drive male semelparity in dasyurid marsupials?

In some members of the marsupial families Didelphidae and Dasyuridae, males are semelparous, that is, they live for only one mating season. Semelparity is proposed to be the result of the high energy demands of competing for matings with many females during a short breeding season. We argue that high adult female mortality rates between mating and weaning of the offspring selects for a 'bethedging' mating strategy in males. We tested this hypothesis in a well-studied field population of Antechinus agilis by estimating the number of females a male needs to mate with in order to have a high chance of siring at least one offspring that survives to the next breeding season. Our hypothesis predicts that species in which males are semelparous should have higher female mortality rates than species in which males are iteroparous. The limited available data for dasyurid marsupials support this prediction.     

Trends in schistosomiasis-related mortality in Brazil, 2000–2011

Schistosomiasis is an important public health problem, with high morbidity and mortality in endemic countries. We analysed the epidemiological characteristics and time trends of schistosomiasis-related mortality in Brazil. We performed a nationwide study based on official mortality data obtained from the Brazilian Mortality Information System. We included all deaths in Brazil between 2000 and 2011, in which schistosomiasis was mentioned on the death certificate as an underlying or associated cause of death (multiple causes of death). We calculated crude and age-adjusted mortality rates (per 100,000 inhabitants), and proportional mortality rates. Trends over time were assessed using joinpoint regression models. Over the 12-year study period, 12,491,280 deaths were recorded in Brazil. Schistosomiasis was mentioned in 8,756 deaths, including in 6,319 (72.2%) as an underlying cause and in 2,437 (27.8%) as an associated cause. The average annual age-adjusted mortality rate was 0.49 deaths/100,000 inhabitants (95% confidence interval: 0.46–0.52) and proportional mortality rate was 0.070% (95% confidence interval: 0.069–0.072). Males (0.53 deaths/100,000 inhabitants), those aged ⩾70 years (3.41 deaths/100,000 inhabitants), those of brown race/colour (0.44 deaths/100,000 inhabitants), and residents in the Northeast region of Brazil (1.19 deaths/100,000 inhabitants) had the highest schistosomiasis-related death rates. Age-adjusted mortality rates showed a significant decrease at a national level (Annual Percent Change: −2.8%; 95% confidence interval: −4.2 to −2.4) during the studied period. We observed decreasing mortality rates in the Northeast (Annual Percent Change: −2.5%; 95% confidence interval: −4.2 to −0.8), Southeast (Annual Percent Change: −2.2%; 95% confidence interval: −3.6 to −0.9), and Central-West (Annual Percent Change: −7.9%; 95% confidence interval: −11.3 to −4.3) regions, while the rates remained stable in the North and South regions. Despite the reduced mortality, schistosomiasis is still a neglected cause of death in Brazil, with considerable regional differences. Sustainable control measures should focus on increased coverage, and intensified and tailored control measures, to prevent the occurrence of severe forms of schistosomiasis and associated deaths.