Grassland connectivity by motor vehicles and grazing livestock

In addition to habitat loss and fragmentation, agricultural change has led to a change in seed dispersal processes in the rural landscape through a loss of structural and functional connectivity. Here, human‐mediated dispersal vectors are prevalent, and we explored whether the loss of connectivity via free‐ranging livestock could be mitigated by the increase in roads and motor vehicles. We found that structurally, 39% of all valuable semi‐natural grassland habitats in southern Sweden are adjacent to public road verges, which in the rural landscape are often considered to be suitable habitat for grassland species. Additionally, by collecting mud attached to cars and farming machinery and manure from livestock (cattle, horse, sheep) grazing semi‐natural grassland pasture, we found that motor vehicles are also capable seed dispersers. A similar number of species were dispersed by both vectors, although the composition of samples was quite different. Motor vehicles dispersed more grassland specialists than invasive species, although in much lower abundances than did grazing livestock. Despite these differences, motor vehicles were found to be able to disperse species with the same kinds of dispersal traits as livestock. A high number of seeds, species and specialists in manure samples means that greater movement of livestock is desirable to increase functional grassland connectivity. However, effective management could improve the suitability of roadsides as grassland corridors and increase the availability of seeds for long‐distance human‐mediated dispersal via cars and tractors. Our results suggest that in many rural landscapes, connectivity by road networks could help mediate habitat loss and fragmentation of grasslands. However, such effects can be context dependent, and the connectivity provided by roads could have serious negative consequences in other regions.     

ADHD and comorbid conduct problems among adolescents: associations with self-esteem and substance use

Attention-deficit/hyperactivity disorder (ADHD) is a common child and adolescent disorder that is associated with negative outcomes (e.g., emotional and behavioral problems, substance use) and is often comorbid with Conduct Problems (CP). Research findings are mixed as to whether youth with ADHD alone or comorbid ADHD/CP suffer from low self-esteem. Research has also shown links between low self-esteem and ADHD (alone and with CP) with substance use; yet, no research has examined the links between self-esteem and substance use in adolescents with ADHD and CP. The current study examined the relation between ADHD with and without comorbid CP and self-esteem, and whether self-esteem moderated the relation between ADHD and ADHD/CP with substance use among adolescents. We hypothesized that adolescents with comorbid ADHD/CP would experience lower self-esteem than adolescents with ADHD alone or with neither disorder and that self-esteem would moderate the association between ADHD, CP, and substance use. Participants were 62 adolescents who completed the laboratory-based study with a parent. Results suggested that adolescents with comorbid ADHD and CP had significantly lower self-esteem than adolescents with ADHD alone or neither disorder. Self-esteem was not significantly different for adolescents with ADHD alone versus those in the control group. There was one marginally significant interaction between ADHD and self-esteem predicting substance use, such that individuals with comorbid ADHD/CP who also had low self-esteem tended to use more substances. Results have implications for treatments that target adolescents with ADHD and comorbid CP, as these adolescents are at risk for many deleterious outcomes.     

Mobile telephone use is associated with changes in cognitive function in young adolescents

As part of the Mobile Radiofrequency Phone Exposed Users' Study (MoRPhEUS), a cross‐sectional epidemiological study examined cognitive function in secondary school students. We recruited 317, 7th grade students (144 boys, 173 girls, median age 13 years) from 20 schools around Melbourne, Australia. Participants completed an exposure questionnaire based on the Interphone study, a computerised cognitive test battery, and the Stroop colour‐word test. The principal exposure metric was the total number of reported mobile phone voice calls per week. Linear regression models were fitted to cognitive test response times and accuracies. Age, gender, ethnicity, socio‐economic status and handedness were fitted as covariates and standard errors were adjusted for clustering by school. The accuracy of working memory was poorer, reaction time for a simple learning task shorter, associative learning response time shorter and accuracy poorer in children reporting more mobile phone voice calls. There were no significant relationships between exposure and signal detection, movement monitoring or estimation. The completion time for Stroop word naming tasks was longer for those reporting more mobile phone voice calls. The findings were similar for total short message service (SMS, also known as text) messages per week, suggesting these cognitive changes were unlikely due to radiofrequency (RF) exposure. Overall, mobile phone use was associated with faster and less accurate responding to higher level cognitive tasks. These behaviours may have been learned through frequent use of a mobile phone. Bioelectromagnetics 30:678–686, 2009. © 2009 Wiley‐Liss, Inc.     

Catechol‐O‐methyltransferase gene methylation and substance use in adolescents: the TRAILS study

Substance use often starts in adolescence and poses a major problem for society and individual health. The dopamine system plays a role in substance use, and catechol‐O‐methyltransferase (COMT) is an important enzyme that degrades dopamine. The Val^108/158Met polymorphism modulates COMT activity and thus dopamine levels, and has been linked to substance use. COMT gene methylation, on the other hand, may affect expression and thus indirectly COMT activity. We investigated whether methylation of the COMT gene was associated with adolescents' substance use. Furthermore, we explored whether the COMT Val^108/158Met polymorphism interacts with COMT gene methylation in association with substance use. In 463 adolescents (mean age = 16, 50.8% girls), substance use (cigarette smoking, alcohol and cannabis use) was assessed with self‐report questionnaires. From blood samples, COMT Val^108/158Met genotype and methylation rates of membrane bound (MB) and soluble (S) COMT promoters were assessed. MB‐COMT promoter methylation was associated with non‐daily smoking [odds ratio (OR) = 1.82, P = 0.03], but not with daily smoking (OR = 1.20, P = 0.34), MB‐COMT promoter methylation was not associated with alcohol use. Adolescents with the Met/Met genotype and high rates of MB‐COMT promoter methylation were less likely to be high‐frequent cannabis users than adolescents with the Val/Val or Val/Met genotype. S‐COMT promoter methylation was not associated with substance use. These results indicate that there is an association between substance use and COMT gene methylation. Although this association is complex, combining genetic and epigenetic variation of the COMT gene may be helpful in further elucidating the influence of the dopamine system on substance use in adolescence.     

The forensic use of luminol chemiluminescence to detect traces of blood inside motor vehicles.

The luminol test for blood was carried out on a set of interior fittings and surfaces inside three different makes of modern motor car. The surfaces and fittings provided little interference with the test for blood, although there was some detectable chemiluminescence when the test was applied to blood-free material from a seatbelt, a boot-lining and a gear-knob. The case with which haemoglobin samples could be washed off interior car surfaces was also examined for seat fabrics, carpets, roof-linings and various other plastic interior surfaces. A standard wash with water alone was not very effective and removed only ca. 50% of the haemoglobin. A standard wash with soapy water or with a proprietary multipurpose car cleaner removed ca. 90% of the haemoglobin from the tested surface. The effect of high car interior temperatures on haemoglobin samples that were subsequently used in the luminol test was also examined. It was shown that the sensitivity of the luminol test was not decreased but was increased by the prior heating of a haemoglobin sample. This effect was attributed to the thermal conversion of haemoglobin to the more brighter catalyst for chemiluminescence, methaemoglobin. The enthalpy of this conversion in the solid state was found to be 14.1 kJ/mol.     

Drug consumptions by the young adolescents: 1. Epidemiological data

Adolescence is often the time of experimentation with psychoactive substances, sometimes leading to more regular use. This paper gives an update of drug consumptions by the young adolescents, from results of recent general population surveys in France, and focuses on the specificity of this consumption when compared to that of older adolescents. It shows that regular uses of such substances usually do not start before the age of 14, but that early initiated adolescents show a higher risk of moving towards more intensive or problematic uses. Through presenting the limitations of such surveys, the authors discuss the nature of the link observed between early experimentation and level of use: while acknowledging the unquestionable prognostic value of early initiation to predict future problematic use, they show that its interpretation should be made with caution when based on such transversal epidemiological surveys.     

Benzodiazepine use and abuse in Canada.

Benzodiazepines are frequently prescribed, yet the extent of their use in Canada has not been described. Such data would be valuable in assessing patient exposure to benzodiazepines and would provide a context to estimate the risk-benefit ratio of these drugs. Analysis of benzodiazepine sales in 1978-87 in Canada, expressed as the defined daily dose (DDD) per 1000 inhabitants per day, showed that the use of these drugs was stable during the first half of the decade, at 33 DDD/1000 inhabitants per day, then steadily increased from 1983 to 1987, reaching 48 DDD/1000 inhabitants per day in 1987. The total use of slowly eliminated benzodiazepines declined, whereas the overall use of rapidly eliminated benzodiazepines increased linearly. In 1978-83 Canada had the second-lowest total benzodiazepine use among several Western countries. The patterns of use and abuse of rapidly eliminated benzodiazepines in 1978-84 showed a close correlation. Our findings indicate that data on drug use can be monitored and linked to clinical data, providing a mechanism for monitoring the relation between use and related illness.     

Acetylcholinesterase: a histochemical identification of motor and sensory fascicles in human peripheral nerve and its use during operation

To evaluate the precision of acetylcholinesterase histochemical identification of motor and sensory fascicles, this study presents a systematic observation of human peripheral nerves by Karnovsky and Roots' histochemical method. The results indicate that either of the enzymatic activities of myelinated and unmyelinated fibers was different between motor and sensory fascicles. Fifty-seven percent of the myelinated fibers showed enzymatic activity in the motor fascicles, while none of the myelinated fibers in the sensory fascicles showed enzymatic activity. The unmyelinated fibers showing enzymatic activity in the sensory fascicles were far denser than those in the motor fascicles. Our study demonstrated that the unmyelinated fibers were sympathetic postganglionic unmyelinated fibers. From these results it is concluded that the motor and sensory fascicles may be identified not only according to the enzymatic activities of the myelinated fibers, but also according to the enzymatic activities of the sympathetic postganglionic unmyelinated fibers. An improved histochemical method was suggested for its applicability as a method of intraoperative nerve fascicle identification. Simulated experiments were done on the radial nerves and the median nerves in human cadavers. This improved histochemical process can be completed within 50 minutes and can be used in intraoperative nerve fascicle identification.     

Anthropometric and motor features of young judoists in Vojvodina

The aim of the study was to identify differences between trained and untrained subjects with respect to body composition and motor abilities. Two groups of subjects participated in the study: young judoists (110 boys and 56 girls) and their untrained mates (115 boys and 60 girls), aged 11 to 16 years, all from the Province of Vojvodina, Serbia. Young male judoists proved significantly better than their untrained mates in repetitive and static strength exercises, running speed, whole-body coordination, and had lower subcutaneous fat tissue of the upper arm. Young female judoists were significantly better in repetitive strength, whole-body coordination and plate tapping, chest girth and stretched upper arm, and also had lower subcutaneous fat tissue of the upper arm and back.     

Global regulations on diabetic treated with insulin and their operation of commercial motor vehicles. DiaMond Project Group on Social Issues.

Governments often regulate who may and may not drive vocationally for public safety purposes. Recent arguments, however, imply that employment opportunities may be limited unnecessarily for people with medical impairments. Drivers with diabetes treated with insulin are commonly perceived to pose an increased risk of accidents because of their susceptibility to hypoglycaemia. Much uncertainty, though, surrounds the data on the risks of these drivers. An international survey studied the licensing policies applied to professional lorry drivers with diabetes treated with insulin. Responses from 24 countries indicated that regulations differ considerably; ranging from a complete ban on professional driving to no restrictions at all. Many reasons may explain this difference, including the lack of data on the effects of hypoglycaemia on the incidence of traffic accidents. A proper account of the risks of diabetic drivers is necessary to balance fairly the rights of employment against the risks.     

Horned grebe habitat use of constructed wetlands in Alberta,Canada

Wetland degradation has resulted in declines in populations of aquatic birds throughout North America. Horned grebe (Podiceps auritus), a migratory diving bird experiencing population decline, may benefit from wetland construction. We examined horned grebe use of borrow pits (ponds created during highway construction) in Alberta, Canada. Our goals were to document patterns of occurrence and breeding success of grebes on borrow pits and to determine if occupied and unoccupied sites differed in local habitat or landscape characteristics. In May 2003 and 2007, 330 constructed ponds were surveyed for horned grebes. We chose 100 occupied and 100 unoccupied ponds for additional surveys in 2007 and 2008, and collected habitat and landscape data for these sites. We used generalized linear mixed model and generalized linear model regression, coupled with Akaike's Information Criterion, to determine which environmental variables were most effective in explaining occurrence of horned grebes. The best model included all measured local and landscape habitat features. Horned grebes occurred on 36% of ponds in May 2003 and 2007, and chicks were produced on 74.5–81.3% of occupied ponds in 2007 and 2008. Grebes occupied larger ponds with more emergent and riparian vegetation and avoided ponds that supported beavers, contained human structures, and were primarily surrounded by forest within 1 km. On ponds with grebe pairs, chicks were produced more often on sites surrounded by more riparian vegetation. We conclude that the construction of small wetlands offers a promising means of increasing breeding habitat for horned grebes and present specific recommendations for breeding pond construction. © 2012 The Wildlife Society.     

Prevalence of asthma among Chinese adolescents living in Canada and in China

Background

Studies of the prevalence of asthma among migrating populations may help in identifying environmental risk factors.

Methods

We analyzed data from Vancouver, Canada, and from Guangzhou, Beijing and Hong Kong, China, collected during phase 3 of the International Study of Asthma and Allergies in Childhood. We subdivided the Vancouver adolescents according to whether they were Chinese immigrants to Canada, Canadian-born Chinese or Canadian-born non-Chinese. We compared the prevalence of asthma and wheezing among Chinese adolescents born in Canada, Chinese adolescents who had immigrated to Canada and Chinese adolescents living in China.

Results

Of 7794 Chinese adolescents who met the inclusion criteria, 3058 were from Guangzhou, 2824 were from Beijing, and 1912 were from Hong Kong. Of 2235 adolescents in Vancouver, Canada, 475 were Chinese immigrants, 617 were Canadian-born Chinese, and 1143 were Canadian-born non-Chinese. The prevalence of current wheezing among boys ranged from 5.9% in Guangzhou to 11.2% in Canadian-born Chinese adolescents. For girls, the range was 4.3% in Guangzhou to 9.8% in Canadian-born Chinese adolescents. The prevalence of ever having had asthma ranged from 6.6% to 16.6% for boys and from 2.9% to 15.0% for girls. Prevalence gradients persisted after adjustment for other environmental variables (odds ratios for ever having had asthma among Canadian-born Chinese compared with native Chinese in Guangzhou: 2.72 [95% confidence interval 1.75–4.23] for boys and 5.50 [95% confidence interval 3.21–9.44] for girls; p < 0.001 for both). Among Chinese adolescents living in Vancouver, the prevalence of ever wheezing increased with duration of residence, from 14.5% among those living in Canada for less than 7 years to 20.9% among those living their entire life in Canada. The same pattern was observed for the prevalence of ever having had asthma, from 7.7% to 15.9%.

Interpretation

Asthma symptoms in Chinese adolescents were lowest among residents of mainland China, were greater for those in Hong Kong and those who had immigrated to Canada, and were highest among those born in Canada. These findings suggest that environmental factors and duration of exposure influence asthma prevalence.The prevalence of asthma symptoms exhibits large geographic variations, even among genetically similar groups,^1,2 which suggests that differences may reflect variation in environmental factors. Epidemiologic studies have demonstrated associations between asthma and exposure to household allergens,³ pets,⁴ environmental tobacco smoke⁵ and environmental pollution,⁶ as well as sex,⁷ obesity,⁸ number of siblings and birth order,⁹ and maternal education.¹⁰ Increasing “westernization” of environmental factors (such as changes in maternal diet, smaller family size, fewer infections during infancy, increased use of antibiotics and vaccination, less exposure to rural environments and improved sanitation) has been associated with an increased risk of childhood asthma.¹¹ Conversely, the hygiene hypothesis proposed by Strachan in 1989 suggested that infections and contact with older siblings may reduce the risk of allergic diseases.¹²Migration studies examining children of the same ethnic background living in different environments for part or all of their lives may help to identify factors relevant to the development of diseases and may explain some of the observed geographic variations in prevalence. In the International Study of Asthma and Allergies in Childhood, prevalence rates for asthma in Canada were among the highest in the world, whereas those in China were among the lowest.² This difference could reflect genetic or environmental factors. China has been and continues to be a major source of international migration.^13,14 Of immigrants in Vancouver, Canada, who landed between 1985 and 2001, half were born in East Asia, mainly Hong Kong and mainland China.¹⁵ Few studies on the prevalence of asthma among immigrants have been undertaken in Canada,¹⁶ and data for Chinese people living in Canada are not available.We hypothesized that the prevalence of asthma would be highest among Canadian-born Chinese adolescents, lower among Chinese adolescents who had immigrated to Canada and lowest among Chinese adolescents living in China. We further hypothesized that, among Chinese immigrants to Canada, prevalence rates of asthma would relate to duration of residence in Canada.     

Home range and habitat use of wolverines Gulo gulo in Yukon, Canada

Home ranges and habitat use are described for three adult female, one adult male, and one subadult male wolverines in the Kluane Game Sanctuary, Yukon. When long distance excursions are not included, home ranges of wolverines in the Kluane Game Sanctuary were between 76 and 269 km² for females and 209 and 269 km² for males. Habitat use of females was similar to habitat availability. Males used subalpine coniferous habitats more frequently than other habitat types during winter. Although individual variation in the use of forest cover types, aspects, slopes and elevations was apparent, seasonal use did not differ from availability for each sex. Within the 1590 km² study area, three adult males and six adult females were present, corresponding to a density of one resident wolverine 177 km^-2.