Alginate block structure in phaeophyceae from Nova Scotia: Variation with species,environment and tissue-type

The block composition of alginate from a number of Phaeophyceae from Nova Scotia, Canada, has been determined by circular dichroism analysis. Laminaria longicruris from three different ecological locations shows appreciable morphological variation, which is reflected in differences in alginate composition of the blades. Stipe material shows less variability, but is higher in polyguluronate, consistent with the greater mechanical rigidity of this tissue. Similarly, differences in alginate composition with tissue type and growth location have been observed for L. digitata. Agarum cribrosum shows little tissue-to-tissue variation in alginate composition, material from both blades and mid-ribs being very similar in block structure to commercially available alginate from Macrocystis pyrifera and Ascophyllum nodosum. Stilophora rhizodes and Leathesia difformis, from the order Ectocarpales, both yield alginate of very high polyguluronate content, consistent with the brittle texture of both species. Stilophora rhizoides harvested during two consecutive growing seasons showed no appreciable variation in alginate block structure. Two alginate samples analysed in this work (from Leathesia difformis and from blades of Laminaria longicruris from one of the populations studied) show respectively higher and lower levels of the structure-forming polyguluronate sequences than any previously reported alginate samples from mature plant tissue.     

Acid Sensitivity of Lakes in Nova Scotia,Canada: Assessment of Lakes at Risk

The sensitivity of surface waters to acidic deposition is governed by the interaction of catchment geology, soils, topography, land use, climate and atmospheric deposition. Accordingly at the landscape scale, catchment attributes may be used to predict lake chemistry (for example, acid neutralising capacity (ANC), pH, calcium (Ca²⁺) and dissolved organic carbon (DOC)). Empirical (multiple linear regression) models based on average measured chemistry (2000–2006) for 204 lakes in Nova Scotia (NS) Canada, and their catchment attributes, were used to predict chemistry for all lakes in NS (n = 6104). Damage to aquatic biota, such as loss of species and/or reduced biodiversity has been widely evaluated using critical chemical thresholds commonly based on pH, ANC and Ca²⁺. The proportion of sensitive lakes in NS (that is, the stock at risk) was estimated as lakes with ANC less than 20 μeq l⁻¹, pH below 6, and Ca²⁺ less than 75 μeq l⁻¹ (13, 73 and 74%, respectively). Many lakes in NS are characterized by high DOC (>7 mg l⁻¹); in these lakes organic acids contribute to total acidity, making anthropogenic influences difficult to discern. To account for the potential contribution of organic acidity, all lakes with pH below 6 (and DOC < 7 mg l⁻¹) and lakes below a threshold for ANC adjusted for organic acids were quantified; 63% of the lakes fell below either of these thresholds. Despite substantial reductions in sulphur emissions in North America since the 1980s, many lakes in NS remain at risk to acidic deposition.     

Echinoids,epizootics and ecological stability in the rocky subtidal off Nova Scotia,Canada

Mass mortalities ofStrongylocentrotus droebachiensis, attributed to disease, have occurred along the Atlantic coast of Nova Scotia from 1980 to 1982. An amoeboid protist has been tentatively identified as the pathogenic agent. Temperature appears to play an important role in triggering epizootics and determining the extent of mortality. Epizootics have occurred in the autumn of each year during months of record high temperatures. The virtual elimination of echinoids over a large area of coast has enabled regeneration of kelp beds. Disease may play a key role in determining the structure and stability of benthic communities off Nova Scotia and elsewhere by controlling echinoid abundance.     

Fishing and fertility: a study of a Nova Scotia fishing village.

The relationship between fertility and occupation is compared for: 1) deep-sea fishermen who are away from home as long as 21 days at a time with short rests between; 2) in-shore fishermen who are away at sea most nights; and 3) plant workers in the locality, used as controls. Particular attention was given to the families of fishermen who had done the same job since marriage. The population was old, relatively speaking, due to outmigration of younger people. 73% of the wives were over 30 years of age. Deep-sea fishermen are younger and have higher incomes than in-shore men (42.1 years vs 49.7 and $3544 vs $2900). Among women 15-44 years of age mean number of children for deep-sea fishermen was 3.35; in-shore, 3.60; plant workers, 3.62. Among those whose husbands had held the same job since marriage the variation was greater: deep-sea, 2.54; in-shore, 3.46; plant workers, 3.35. Among women over 45-years-old whose husbands had held the same job since marriage the number of children was 2.61, 3.94, and 4.27, respectively. 33% of plant workers had more children than desired and 66.7% said they had as many as desired. However, 25.9% of in-shore fishermen and 50% of deep-sea fishermen had fewer than desired. Interval between births was similar for all occupational groups (23.5-26.7 months) but the wives of deep-sea fishermen terminated childbearing earlier. Contraception was used only by the younger women, usually coitus interruptus or rhythm. Sterilization may have been important but it was hard to find out whether the 15% of wives who reported operations which made further childbearing impossible intended sterilization. 35.7% of deep-sea fishermens' wives reported such operations, generally women with larger families.     

A novel formulary: collaboration between health care professionals,seniors, private sector and government in Nova Scotia

A novel formulary has been developed in Nova Scotia with the objective of providing quality treatment with needed medications at affordable cost. Creation of the formulary has involved collaboration among health care professionals, seniors, the Department of Health and pharmaceutical companies. This is the first Canadian formulary to use the Anatomic, Therapeutic, Chemical system. Drug listing is comprehensive rather than exclusive. Colour-coded recommendations on use assist physicians with drug choice. Relative costs are indicated within each therapeutic grouping. Listings indicate drugs approved for reimbursement, interchangeable medications, maximum allowable cost, drug identification number and manufacturer code. Treatment summaries provide brief overviews of therapeutic advice. Updates on new products and new or modified treatment summaries are provided every 6 months. The formulary will be the focus of coordinated educational activities on treatment for seniors and health care professionals.     

The experience and effectiveness of the Nova Scotia Rh program, 1964-84.

A program to reduce the incidence of erythroblastosis fetalis was started in Nova Scotia in 1964. Up to the end of 1984, 120 fetuses received 247 intrauterine transfusions. The survival rate was 45.6% in the first 10 years of the program and 66.7% in the next 11 years. For fetuses at or over 26 weeks'' gestation the figures were 51.5% and 73.7% respectively. Postpartum prevention was started in 1968, with administration of Rh immune globulin (RhIG) to Rh-negative unimmunized women within 72 hours after the birth of an Rh-positive infant. Antepartum prevention, started in 1979, consisted of administration of RhIG at 28 weeks'' gestation to Rh-negative unimmunized women. The effectiveness of the prevention program was evaluated by enumerating the known cases of Rh(D) alloimmunization in the province from 1982 to 1984: 55 cases were identified, a rate of 1.5 per 1000 births instead of the expected rate of about 10 per 1000.     

Toward a global view of alcohol, tobacco, cannabis, and cocaine use: findings from the WHO World Mental Health Surveys

Background

Alcohol, tobacco, and illegal drug use cause considerable morbidity and mortality, but good cross-national epidemiological data are limited. This paper describes such data from the first 17 countries participating in the World Health Organization''s (WHO''s) World Mental Health (WMH) Survey Initiative.

Methods and Findings

Household surveys with a combined sample size of 85,052 were carried out in the Americas (Colombia, Mexico, United States), Europe (Belgium, France, Germany, Italy, Netherlands, Spain, Ukraine), Middle East and Africa (Israel, Lebanon, Nigeria, South Africa), Asia (Japan, People''s Republic of China), and Oceania (New Zealand). The WHO Composite International Diagnostic Interview (CIDI) was used to assess the prevalence and correlates of a wide variety of mental and substance disorders. This paper focuses on lifetime use and age of initiation of tobacco, alcohol, cannabis, and cocaine. Alcohol had been used by most in the Americas, Europe, Japan, and New Zealand, with smaller proportions in the Middle East, Africa, and China. Cannabis use in the US and New Zealand (both 42%) was far higher than in any other country. The US was also an outlier in cocaine use (16%). Males were more likely than females to have used drugs; and a sex–cohort interaction was observed, whereby not only were younger cohorts more likely to use all drugs, but the male–female gap was closing in more recent cohorts. The period of risk for drug initiation also appears to be lengthening longer into adulthood among more recent cohorts. Associations with sociodemographic variables were consistent across countries, as were the curves of incidence of lifetime use.

Conclusions

Globally, drug use is not distributed evenly and is not simply related to drug policy, since countries with stringent user-level illegal drug policies did not have lower levels of use than countries with liberal ones. Sex differences were consistently documented, but are decreasing in more recent cohorts, who also have higher levels of illegal drug use and extensions in the period of risk for initiation.     

The Smallest Known Tetrapod Footprints: Batrachichnus Salamandroides from the Carboniferous of Joggins,Nova Scotia,Canada

A new specimen of Batrachichnus salamandroides from the classic Carboniferous section at Joggins, Nova Scotia, is the smallest set of tetrapod footprints known in the fossil record. The trackmaker was a juvenile, quadrupedal temnospondyl or microsaur with a trunk length of 3.55 mm and an estimated body length of 8 mm (skull, presacral vertebrae, and caudal vertebrae). The 48 mm-long trackway preserves a high degree of extramorphological variation along its course, including a gait change associated with a change in direction along with an increased stride and pace, and the appearance of overstepped imprints, in the latter portion of the trackway. These morphological changes suggest the tetrapod changed from a walking gait to a running gait.     

Long-term lake acidification trends in high- and low-sulphate deposition regions from Nova Scotia,Canada

Diatom-based paleolimnological techniques were used to study 14 lakes from two regions of Nova Scotia which represent regions of high and low sulphate deposition. Using decadal scale intervals, changes in diatom assemblages and diatom-inferred pH were tracked in relation to deposition of anthropogenic-sourced strong acids. Eight study lakes were located in Kejimkujik National Park in the southwestern part of the province, which receives an annual sulphate deposition (2000–2002) of ~10.5 kg ha⁻¹ yr⁻¹. These lakes showed significant changes in diatom assemblages with overall diatom-inferred acidification of ~0.5 pH units starting between 1925 and 1940, with the timing of acidification related to pre-industrial (or pre−1850) lakewater pH. Six study lakes were located in Cape Breton Highlands National Park, in northern Nova Scotia, a region of lower sulphate deposition. These lakes did not show any consistent trends in diatom assemblages or inferred pH values consistent with recent acidic deposition, but rather variations that may be related to climatic influences. Nova Scotia lakes that have been most impacted by acidic deposition had the lowest pre-industrial lakewater pH values and were in an area of relatively high sulphate deposition. Handling editor: K. Martens     

Stressful life events and drug use among adolescents

The authors investigated the hypothesis that increased amounts of stress during and/or prior to adolescence would be associated with elevated use or abuse of drug substances by adolescents. Through the study the authors also provided further information regarding the usefulness of various techniques of life event surveying in the measurement of presumptive stress among adolescents. Using a multivariate analysis of the data, a number of conclusions were drawn with the overall conclusion that increased life stress levels are significantly associated with elevated drug use.     

Repeated call sequences and behavioural context in long-finned pilot whales off Cape Breton,Nova Scotia,Canada

Repeated calls are part of the vocal repertoire of a diverse array of species, often presented in sequences that take time and effort on the part of the signal producer. Rhythmic repeated call sequences make up a significant portion of long-finned pilot whale (Globicephala melas) vocal production, yet the function of these sequences has not been investigated until now. In this study, we explored the relationship between behavioural context and the presence of these vocal sequences using recordings of a population of pilot whales found off Cape Breton, Nova Scotia, Canada. We used a binomial logit-link generalized linear model to look for possible predictors of the presence of repeated call sequences. They were more common in recordings of socializing whales than in those of whales in other behavioural states, and least common in resting whales. These vocal repetitions were also more common with larger group size. These results suggest that sequences function in maintaining contact and cohesion within this social species, possibly also serving in individual or group identification. The context of repeated call sequences indicate that they are not primarily mother–calf interactions, as they are heard just as commonly from groups without young. Future studies of pilot whale repeated call sequences should include individual-level behaviour and detailed acoustic calling context.