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Most previous workers have regarded the insoluble residues of high-purity Quaternary limestones (coral reefs and oolites) as the most important parent material for well-developed, clay-rich soils on Caribbean and western Atlantic islands, but this genetic mechanism requires unreasonable amounts of limestone solution in Quaternary time. Other possible parent materials from external sources are volcanic ash from the Lesser Antilles island arc and Saharan dust carried across the Atlantic Ocean on the northeast trade winds. Soils on Quaternary coral terraces and carbonate eolianites on Barbados, Jamaica, the Florida Keys (United States), and New Providence Island (Bahamas) were studied to determine which, if either, external source was important. Caribbean volcanic ashes and Saharan dust can be clearly distinguished using ratios of relatively immobile elements (Al2O3/TiO2, Ti/Y, Ti/Zr, and Ti/Th). Comparison of these ratios in 25 soils, where estimated ages range from 125,000 to about 870,000 yr, shows that Saharan dust is the most important parent material for soils on all islands. These results indicate that the northeast trade winds have been an important component of the regional climatology for much of the Quaterary. Saharan dust may also be an important parent material for Caribbean island bauxites of much greater age.
Lipoprotein-associated phospholipase A2 (Lp-PLA2) is an independent risk factor for CVD and has been proposed as a marker of vascular inflammation. Polyunsaturated n-3 fatty acids (FA) and several n-6 FA are known to suppress inflammation and may influence Lp-PLA2 mass and activity. The associations of n-3 and n-6 plasma FA with Lp-PLA2 mass and activity were analysed using linear regression analysis in 2246 participants of the Multi-Ethnic Study of Atherosclerosis; statistical adjustments were made to control for body mass, inflammation, lipids, diabetes, and additional clinical and demographic factors. Lp-PLA2 mass and activity were significantly lower in participants with the higher n-3 FA EPA (β = − 4·72, P< 0·001; β = − 1·53; P= 0·023) and DHA levels (β = − 4·47, β = − 1·87; both P< 0·001). Those in the highest quintiles of plasma EPA and DHA showed 12·71 and 19·15 ng/ml lower Lp-PLA2 mass and 5·7 and 8·90 nmol/min per ml lower Lp-PLA2 activity than those in the first quintiles, respectively. In addition, lower Lp-PLA2 mass and activity were associated with higher levels of n-6 arachidonic acid (β = − 1·63, β = − 1·30; both P< 0·001), while γ-linolenic acid was negatively associated with activity (β = − 27·7, P= 0·027). Lp-PLA2 mass was significantly higher in participants with greater plasma levels of n-6 linoleic (β = 0·828, P= 0·011) and dihomo-γ-linolenic acids (β = 4·17, P= 0·002). Based on their independent associations with Lp-PLA2 mass and activity, certain n-3 and n-6 FA may have additional influences on CVD risk. Intervention studies are warranted to assess whether these macronutrients may directly influence Lp-PLA2 expression or activity.
We examined the relationship between whole grain intake and obesity, insulin resistance, inflammation, diabetes and subclinical CVD using baseline data from the Multi-Ethnic Study of Atherosclerosis. Whole grain intake was measured by a 127-item FFQ in 5496 men and women free of CHD and previously known diabetes. Mean whole grain intake was 0·5 (sd 0·5) servings per d; biochemical measures reflect fasting levels. After adjustment for demographic and health behaviour variables, mean differences for the highest quintile of whole grain intake minus the lowest quintile of intake were 0·6 kg/m2 for BMI, 0·36 mg/l for C-reactive protein, 0·82 μmol/l for homocysteine, 0·15 mU/l*mmol/l for homeostasis model assessment (HOMA), 0·48 mU/l for serum insulin, 2·0 mg/dl for glucose and 5·7 % for prevalence of newly diagnosed impaired fasting glucose (glucose ≥ 100 mg/dl or diabetes medication). These differences represent 11–13 % of a standard deviation of BMI, HOMA, glucose and impaired fasting glucose, but 23 %, 52 % and 80 % of a standard deviation of homocysteine, C-reactive protein and insulin, respectively. An inverse association between whole grains and urine albumin excretion was suggested but retained statistical significance after adjustment only in Chinese and Hispanic participants. No associations were observed between whole grain intake and two subclinical disease measures: carotid intima-media thickness and coronary artery calcification. Concordant with previous research, whole grain intake was inversely associated with obesity, insulin resistance, inflammation and elevated fasting glucose or newly diagnosed diabetes. Counter to hypothesis, however, whole grain intake was unrelated to subclinical CVD.
Past studies find that attention deficit hyperactivity disorder (ADHD) creates a higher risk for adverse driving outcomes. This study comprehensively evaluated driving in adults with ADHD by comparing 105 young adults with the disorder (age 17–28) to 64 community control (CC) adults on five domains of driving ability and a battery of executive function tasks. The ADHD group self-reported significantly more traffic citations, particularly for speeding, vehicular crashes, and license suspensions than the CC group, with most of these differences corroborated in the official DMV records. Cognitively, the ADHD group was less attentive and made more errors during a visual reaction task under rule-reversed conditions than the CC group. The ADHD group also obtained lower scores on a test of driving rules and decision-making but not on a simple driving simulator. Both self- and other-ratings showed the CC group employed safer routine driving habits than the ADHD group. Relationships between the cognitive and driving measures and the adverse outcomes were limited or absent, calling into question their use in screening ADHD adults for driving risks. Several executive functions also were significantly yet modestly related to accident frequency and total traffic violations after controlling for severity of ADHD. These results are consistent with earlier studies showing significant driving problems are associated with ADHD. This study found that these driving difficulties were not a function of comorbid oppositional defiant disorder, depression, anxiety, or frequency of alcohol or illegal drug use. Findings to date argue for the development of interventions to reduce driving risks among adults with ADHD.
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