Fossil insect eyes shed light on trilobite optics and the arthropod pigment screen.

Fossilized eyes permit inferences of the visual capacity of extinct arthropods1-3. However, structural and/or chemical modifications as a result of taphonomic and diagenetic processes can alter the original features, thereby necessitating comparisons with modern species. Here we report the detailed molecular composition and microanatomy of the eyes of 54-million-year-old crane-flies, which together provide a proxy for the interpretation of optical systems in some other ancient arthropods. These well-preserved visual organs comprise calcified corneal lenses that are separated by intervening spaces containing eumelanin pigment. We also show that eumelanin is present in the facet walls of living crane-flies, in which it forms the outermost ommatidial pigment shield in compound eyes incorporating a chitinous cornea. To our knowledge, this is the first record of melanic screening pigments in arthropods, and reveals a fossilization mode in insect eyes that involves a decay-resistant biochrome coupled with early diagenetic mineralization of the ommatidial lenses. The demonstrable secondary calcification of lens cuticle that was initially chitinous has implications for the proposed calcitic corneas of trilobites, which we posit are artefacts of preservation rather than a product of in vivo biomineralization4-7. Although trilobite eyes might have been partly mineralized for mechanical strength, a (more likely) organic composition would have enhanced function via gradient-index optics and increased control of lens shape.

Cancer incidence and mortality associated with non-occupational and low dose exposure to Libby vermiculite in Minnesota.

BACKGROUND: A vermiculite processing plant in a Minneapolis, Minnesota neighborhood utilized asbestos-containing ore from Libby, Montana from the late 1930's until 1989. Multiple pathways of exposure to Libby asbestos were characterized in a cohort of over 6000 plant workers and residents living near the plant. OBJECTIVE: We conducted a cohort linkage study to assess the impact of cumulative low dose exposure and the role of occupational history on asbestos-related mortality and cancer morbidity among cohort members residing near a vermiculite plant. METHODS: Cohort members alive in 1988 (n = 5848) were linked to the Minnesota Cancer Surveillance System to identify incident cases of mesothelioma, lung cancer, and all-cancer diagnosed from 1988 to 2010. Proportional incidence ratios (PIRs) were calculated for mesothelioma and lung cancer. Vital status and cause of death were ascertained from Minnesota vital records and the National Death Index (1988-2011). Mortality rates of the cohort (2001-2011) for asbestos-related outcomes were compared to the Minnesota population to estimate standardized mortality ratios (SMRs) and stratified by gender, exposure, and occupational history categories. RESULTS: We identified seven cases of mesothelioma, with elevated incidence only in females (PIR = 11.76, 95% CI: 3.17, 30.12). Lung cancer was elevated in both genders: PIR = 1.54 (95% CI: 1.19, 2.0) in males and 1.62 (95% CI: 1.21, 2.12) in females. We found elevated mortality from COPD, lung cancer, and mesothelioma among females (SMR for mesothelioma in females = 18.97, CI: 3.91, 55.45), among the 546 deaths identified. All four deaths from mesothelioma occurred in the >75th percentile of exposure (>0.0156 fiber/cc x months). The SMR for lung cancer and all respiratory cancer was elevated even after controlling for occupation. CONCLUSIONS: Community exposure to Libby amphibole asbestos from a vermiculite processing plant is associated with increased risk of COPD, lung cancer and mesothelioma incidence and mortality, most notably among females, and is likely to remain a public health issue for years to come.

Estimating the Public Health Impact of Air Pollution for Informing Policy in the Twin Cities: A Minnesota Tracking Collaboration.

OBJECTIVE: The Minnesota Department of Health and the Minnesota Pollution Control Agency used local air pollution and public health data to estimate the impacts of particulate matter and ozone on population health, to identify disparities, and to inform decisions that will improve health. SETTING: While air quality in Minnesota currently meets federal standards, urban communities are concerned about the impact of air pollution on their health. The Twin Cities (Minneapolis-St Paul) metropolitan area includes 7 counties where fine particulate levels and rates of asthma exacerbations are elevated in some communities. DESIGN: We used the Environmental Protection Agency's BenMAP (Environmental Benefits Mapping and Analysis Program) software, along with local PM2.5 (fine particulate) and ozone ambient concentrations, census and population health data, to calculate impacts for 2008 at the zip code level. The impacts were summed across all zip codes for area-wide estimates. American Community Survey data were used to stratify zip codes by poverty and race for assessment of disparities. MAIN OUTCOME MEASURES: Attributable fraction, attributable rate and counts for all-cause mortality, asthma and chronic obstructive pulmonary disease hospitalizations, asthma emergency department (ED) visits, and cardiovascular disease hospitalizations. RESULTS: In the Twin Cities (2008), air pollution was a contributing cause for an estimated 2% to 5% of respiratory and cardiovascular hospitalizations and ED visits and between 6% and 13% of premature deaths. The elderly (aged 65+ years) experienced the highest air pollution-attributable rates of death and respiratory hospitalizations; children experienced the highest asthma ED visit rates. Geographical and demographic differences in air pollution-attributable health impacts across the region reflected the differences in the underlying morbidity and mortality rates. CONCLUSIONS: Method was effective in demonstrating that changes in air quality can have quantifiable health impacts across the Twin Cities. Key messages and implications from this work were shared with the media, community groups, legislators and the public. The results are being used to inform initiatives aimed at reducing sources of air pollution and to address health disparities in urban communities.

Asthma exacerbations and traffic: examining relationships using link-based traffic metrics and a comprehensive patient database.

BACKGROUND: The Rochester Epidemiology Project (REP) is a unique community-based medical record data linkage system that provides individual patient address, diagnosis and visit information for all hospitalizations, as well as emergency department, urgent care and outpatient clinic visits for asthma. Proximity to traffic is known to be associated with asthma exacerbations and severity. Our null hypothesis was that there is no association between residential proximity to traffic and asthma exacerbations over eleven years of REP data. METHODS: Spatial coordinates of the homes of 19,915 individuals diagnosed with asthma were extracted from the REP database. Three metrics of traffic exposure at residences were calculated from link-based traffic count data. We used exploratory statistics as well as logistic and Poisson regression to examine associations between three traffic metrics at the home address and asthma exacerbations. RESULTS: Asthma exacerbations increased as traffic levels near the home increased. Proximity to traffic was a significant predictor of asthma exacerbations in logistic and Poisson regressions controlling for age, gender and block group poverty. CONCLUSIONS: Over eleven years in a comprehensive county-wide data set of asthma patients, and after controlling for demographic effects, we found evidence that living in proximity to traffic increased the risk of asthma exacerbations.

Adult Blood Lead Levels in Minnesota: Rates and Trends, 2005-2012.

Lead exposure is associated with a number of adverse health events including peripheral neuropathy, anemia, renal damage and cognitive impairment. The vast majority of adult lead exposures occur in the workplace. By statute, all results from blood lead level (BLL) tests performed in Minnesota are submitted to the Minnesota Department of Health for surveillance purposes. We analyzed that data to examine lead exposure trends from 2005 through 2012. We found that an average of 548 persons 16 years of age and older had a BLL greater than 10 µg/dL each year during that period. Analysis of the prevalence rate of elevated BLLs among adults for the years 2005-2012 showed a modest, nonsignificant decline among those with BLLs greater than 1O µg/dL. Much has been done to reduce exposures and BLLs among young children. However, the policies and standards that protect workers have not been similarly adjusted, and many workers remain at risk of exposure. Although OSHA is responsible for developing and implementing policies and standards to protect workers, health care providers can play a critical role in identifying cases of lead exposure by asking patients about their occupation and industry. Those working in high-risk industries should be tested to determine whether they have been exposed and intervention is warranted.

The Economic Impact for Farm Injury in Minnesota, 2004-2010.

Only 2% of Minnesota's employed population worked in agriculture between the years 2005 and 2012. However, this small portion of the state's employed population accounted for 31% of total work-related deaths in the state during that same time period. During a similar time period, 2007-2013, the contribution of agriculture to Minnesota's gross domestic product increased from approximately 1.5% to about 2.3%. This article describes the economic impact of injuries related to farm work between the years 2004 and 2010. Using hospital discharge data and the Census of Fatal Occupational Injuries (CFOI), estimates of the number of injuries and fatalities related to agricultural work were compiled. A cost of illness model was applied to these injury and fatality estimates to calculate the related indirect and direct costs in 2010 dollars. Estimated total costs, in 2010 dollars, ranged between $21 and $31 million annually over the 7-year study period. The majority of the costs were attributable to indirect costs, such as lost productivity at work and home. Fatal injuries accrued the largest proportion of the estimated costs followed by hospitalized and nonhospitalized injuries. A sensitivity analysis was performed to evaluate the impact each selected data source had upon the cost estimate. The magnitude of the costs associated with these injuries argues for better surveillance of injury related to agriculture to prioritize resources and evaluate intervention and prevention programs.

Incidence Rates and Trend of Serious Farm-Related Injury in Minnesota, 2000-2011.

Only about 2% of Minnesota's workers were employed in agriculture for the years 2005-2012, this small portion of the workforce accounted for 31% of the 563 work-related deaths that occurred in Minnesota during that same time period. Agricultural fatalities in Minnesota and elsewhere are well documented; however, nonfatal injuries are not. To explore the burden of injury, Minnesota hospital discharge data were used to examine rates and trends of farm injury for the years 2000-2011. Cases were identified through the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM), injury codes and external cause of injury codes (E codes). Probable cases were defined as E code E849.1 (occurred on a farm) or E919.0 (involving agricultural machinery). Possible cases were based on five less specific E codes primarily involving animals or pesticides. Multiple data sources were used to estimate the agricultural population. An annual average of over 500 cases was identified as probable, whereas 2,000 cases were identified as possible. Trend analysis of all identified cases indicated a small but significant average annual increase of 1.5% for the time period 2000-2011. Probable cases were predominantly male (81.5%), whereas possible cases were predominantly female (63.9%). The average age of an injury case was 38.5 years, with the majority of injuries occurring in late summer and fall months. Despite the undercount of less serious injuries, hospital discharge data provide a meaningful data source for the identification and surveillance of nonfatal agricultural injuries. These methods could be utilized by other states for ongoing surveillance for nonfatal agricultural injuries.

4.6-billion-year-old aragonite and its implications for understanding the geological record of Ca-carbonate.

Owing to its diagenetic instability, aragonite is rare in the geological record and almost entirely absent from pre-carboniferous sedimentary rocks. The former presence of this mineral in older deposits has to be inferred from petrographic, chemical or isotopic proxies. Crystals of aragonite that formed around 4563 million years ago occur in carbonaceous chondrite meteorites, showing that under certain conditions, the orthorhombic polymorph of Ca-carbonate can survive essentially indefinitely. Together with other carbonate minerals, phyllosilicates and sulphides, this aragonite formed by low-temperature water-mediated alteration of anhydrous minerals and glass in the interior of the meteorite's parent asteroid(s). The survival of aragonite for such a long time can be attributed to the loss of free water by its incorporation into phyllosilicates, and to the very low permeability of the fine-grained and organic-rich rock matrix that prevented the ingress of fresh solutions via intergranular flow. By analogy with these meteorites, terrestrial aragonite is likely to survive where it has been similarly isolated from liquid water, particularly in organic-rich mudrocks, and such deposits may provide important new evidence for deducing the original mineralogy of skeletal and non-skeletal carbonates in deep-time.

Quantifying traffic exposure.

Living near traffic adversely affects health outcomes. Traffic exposure metrics include distance to high-traffic roads, traffic volume on nearby roads, traffic within buffer distances, measured pollutant concentrations, land-use regression estimates of pollution concentrations, and others. We used Geographic Information System software to explore a new approach using traffic count data and a kernel density calculation to generate a traffic density surface with a resolution of 50 m. The density value in each cell reflects all the traffic on all the roads within the distance specified in the kernel density algorithm. The effect of a given roadway on the raster cell value depends on the amount of traffic on the road segment, its distance from the raster cell, and the form of the algorithm. We used a Gaussian algorithm in which traffic influence became insignificant beyond 300 m. This metric integrates the deleterious effects of traffic rather than focusing on one pollutant. The density surface can be used to impute exposure at any point, and it can be used to quantify integrated exposure along a global positioning system route. The traffic density calculation compares favorably with other metrics for assessing traffic exposure and can be used in a variety of applications.

A demonstration of an affinity between pyrite and organic matter in a hydrothermal setting.

One of the key-principles of the iron-sulphur world theory is to bring organic molecules close enough to interact with each other, using the surface of pyrite as a substrate in a hydrothermal setting. The present paper explores the relationship of pyrite and organic matter in a hydrothermal setting from the geological record; in hydrothermal calcite veins from Carboniferous limestones in central Ireland. Here, the organic matter is accumulated as coatings around, and through, pyrite grains. Most of the pyrite grains are euhedral-subhedral crystals, ranging in size from ca 0.1-0.5 mm in diameter, and they are scattered throughout the matrix of the vein calcite. The organic matter was deposited from a hydrothermal fluid at a temperature of at least 200°C, and gives a Raman signature of disordered carbon. This study points to an example from a hydrothermal setting in the geological record, demonstrating that pyrite can have a high potential for the concentration and accumulation of organic materials.

Preservation of biological markers in clasts within impact melt breccias from the Haughton impact structure, Devon Island.

The 39 +/- 2 Ma Haughton impact structure on Devon Island comprises a thick target succession of sedimentary rocks, mainly carbonates. The carbonates contain pre-impact organic matter, including fossil biological markers. Haughton is located in an area where no major thermal event has affected the sedimentary succession after heating caused by impact. This makes Haughton uniquely suitable for studies concerning the preservation of fossil biological markers following an impact event. Melt breccia is the most common impactite at Haughton. It is composed of clasts of the target, mainly carbonates, embedded in a fine groundmass. The groundmass is composed of material that was melted during impact. In this study, fossil biological marker maturity parameters (tricyclic terpane-hopane ratio and pregnane-sterane ratio) and an aromatic maturity parameter [methylphenanthrene ratio (MPR)] were used to compare the degree of thermal alteration in different size fractions of carbonate clasts (<0.5-4 cm in diameter) and between edges and centers of large carbonate clasts (15-20 cm in diameter). The data show that fossil biological markers can be preserved and detected in isolated large and small fractions of carbonate clasts that are embedded in an impact melt. The results also indicate that there is a thermal gradient from the center of a clast to the edge of a clast, which suggests that biological markers are more likely to be found preserved in the center of a clast. The thermal maturity values point to a higher degree of thermal alteration in the melt breccia carbonate clasts than in the coherent carbonate bedrock.

Asthma among rural Minnesota adolescents.

This study examined the prevalence of and risk factors for wheezing and asthma in rural Minnesota adolescents. A survey querying about wheezing, asthma, farm residence, and other respiratory-related factors was administered to all 9th to 11th grade students (N = 13,490) in a stratified, random sample of high schools in rural Minnesota. Nearly one in 8 (12.6%) students reported ever-diagnosed asthma, and 9.2% reported current asthma. Students living on farms reported less wheezing and asthma than rural non-farm students. Obesity and smoking were associated with wheezing and asthma in all rural adolescents. Asthma rates increased with age among girls and may be largely accounted for by simultaneous increases in smoking rates. Despite the apparent protective effect of farm residence, asthma remains a significant public health issue among rural Minnesota adolescents.

Smoking reduction in the Lung Health Study.

We examined the ability of smokers who failed to quit smoking in the Lung Health Study to reduce the number of cigarettes per day and maintain this reduction and whether reduction predicted increased or decreased future cessation. In the Lung Health Study, among smokers with early lung disease who wished to stop smoking, 3923 were randomized to a special intervention of counseling and nicotine gum for smoking cessation and to bronchodilator therapy or placebo. Among the 1722 who were still smoking at the first year follow-up, 27% smoked the same, 43% smoked 1%-49% fewer, and 30% smoked at least 50% fewer cigarettes per day. Reduction in cigarettes per day was accompanied by reduction in expired-air carbon monoxide. About half of the less-than-50% reducers and one-fifth of the at-least-50% reducers maintained or exceeded this reduction over the next 4 years. Reduction was associated with nicotine gum use. Greater reduction at year 1 predicted more quit attempts in year 2 but not more point prevalence abstinence at year 2 nor more quits or abstinence between years 2 and 5. We conclude that reduction can be maintained but such reduction neither predicts an increased nor decreased probability of future cessation.

The effect of smoking intervention and an inhaled bronchodilator on airways reactivity in COPD: the Lung Health Study.

BACKGROUND: The Lung Health Study (LHS), a 5-year, randomized, prospective clinical trial, studied the effects of smoking intervention and therapy with inhaled anticholinergic bronchodilators on FEV(1) in participants who were 35 to 60 years of age and had mild COPD. Participants were randomized into the following three groups: usual care; smoking cessation plus inhaled ipratropium bromide; and smoking cessation plus placebo inhaler. This report evaluates the effects of these interventions, demographic characteristics, smoking status, and FEV(1) changes on airway responsiveness (AR). METHODS AND RESULTS: Of 5,887 participants, 4,201 underwent methacholine challenge testing both at study entry and study completion. All groups increased AR during the 5-year period. The increase in AR was greatest in continuing smokers and was associated with a greater FEV(1) decline. An intent-to-treat analysis indicated no significant differences in AR changes among the three groups. CONCLUSIONS: Changes in AR over a 5-year period in the LHS were primarily related to changes in the FEV(1). The greater the decline in FEV(1), the greater the increase in AR. Smoking cessation had a small additional benefit in AR beyond its favorable effects on FEV(1) changes.

Changes in smoking status affect women more than men: results of the Lung Health Study.

Lung Health Study participants were smokers aged 35-60 years with mild lung function impairment who participated in a 5-year, 10-center (nine in the United States, one in Canada) clinical trial in 1986-1994. The authors compared the relation of randomized treatment assignments and of smoking history during the study with changes in lung function between men and women. Spirometry was performed annually, and 3,348 men and 1,998 women attended the follow-up clinic visit that included spirometry at year 5. This paper reports on an analysis of changes in lung function by gender, treatment group, and three smoking history categories: sustained quitters, intermittent quitters, and continuing smokers. Among participants who quit smoking in the first year, mean forced expiratory volume in 1 second (FEV(1)) expressed as a percentage of the predicted value of FEV(1 )given the person's age, height, gender, and race (FEV(1)%) increased more in women (3.7% of predicted) than in men (1.6% of predicted) (p < 0.001). Across the 5-year follow-up period, among sustained quitters, women gained more in FEV(1)% of predicted than did men. Methacholine reactivity was more strongly related to rates of decline in women than in men (p < 0.001). Therefore, among persons at risk for chronic obstructive pulmonary disease, smoking cessation has an even clearer advantage for women than it does for men.