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PubMed2000

Preliminary study of the role of red foxes in Echinococcus multilocularis transmission in the urban area of Sapporo, Japan.

In order to assess the infection risk of alveolar echinococcosis among urban residents of Sapporo, the capital of Hokkaido, Japan, a survey was conducted on fox distribution in the urban area and on the prevalence of Echinococcus multilocularis among the foxes. The fox distribution, evaluated from fox footprints left on the snow in parks and woodlands, and from locations of fox carcasses recorded by the Sapporo municipality, was concentrated along the border of the urban area and in the southwestern part of the city, facing the mountain. Fox faeces were collected around active fox dens, and analysed by a coproantigen detection assay and parasite egg examination for the Echinococcus infection. Thirty-three out of 155 faeces were coproantigen positive. Coproantigen-positive faeces were collected from 11 den sites (57.9% of total den sites), and all except 1 were located in the urban fringe. A high intensity of taeniid eggs (> 100 eggs per 0.5 g) containing faeces were also collected in the 3 sites of them. Although Echinococcus infection in rodents was not observed from the necropsy of 23 rodents captured around active fox dens, arvicolid rodents, a suitable intermediate host for E. multilocularis, were captured in the urban fringe. Therefore, the urban fringe offers suitable conditions in which the life-cycle of E. multilocularis could be maintained. Prompt measures to control echinococcus infection should be taken, even in urban areas.

Animals↗
PubMed1992

Pagophagia, or compulsive ice consumption: a historical perspective.

Pagophagia, or the excessive consumption of ice or iced drinks, is popularly regarded as a novel manifestation of pica, which has emerged, predominantly in the USA, over the last 30 years. However, a sampling of historical sources reveals that not only are there warnings in the writings of both Hippocrates and Aristotle concerning the dangers of excessive intake of cold or iced water, but a series of medical works, from the sixteenth century on, incorporate discussion and illustrative case histories about the detrimental effect of immoderate usage of cold water, ice and snow, frequently in the context of disordered eating.

Adolescent↗
PubMed1995

Children's overregularization of English plurals: a quantitative analysis.

This paper brings a quantitative study of children's noun plural overregularizations (foots, mans) to bear on recent comparisons of connectionist and symbolic models of language. The speech of 10 English-speaking children (aged 1;3 to 5;2) from the CHILDES database (MacWhinney & Snow, 1985, 1990) were analysed. The rate of noun overregularization is low, mean = 8.5%, demonstrating that children prefer correct to overregularized forms. Rates of noun overregularization are not significantly different from their rates of past tense overregularization, and noun plurals, like verb past tenses, follow a U-shaped developmental curve in which correct irregulars precede the first overregularized forms. These facts suggest that plural and past tense overregularizations are caused by similar underlying processes. The results pose challenges to connectionist models, but are consistent with Marcus et al.'s (1992) blocking-and-retrieval-failure model in which regulars are generated by a default rule while irregulars are retrieved from the lexicon.

Child Language↗
PubMed1989

Limits on negative information in language input.

Hirsh-Pasek, Treiman & Schneiderman (1984) and Demetras, Post & Snow (1986) have recently suggested that certain types of parental repetitions and clarification questions may provide children with subtle cues to their grammatical errors. We further investigated this possibility by examining parental responses to inflectional over-regularizations and wh-question auxiliary-verb omission errors in the sets of transcripts from Adam, Eve and Sarah (Brown 1973). These errors were chosen because they are exemplars of overgeneralization, the type of mistake for which negative information is, in theory, most critically needed. Expansions and Clarification Questions occurred more often following ill-formed utterances in Adam's and Eve's input, but not in Sarah's. However, these corrective responses formed only a small proportion of all adult responses following Adam's and Eve's grammatical errors. Moreover, corrective responses appear to drop out of children's input while they continue to make overgeneralization errors. Whereas negative feedback may occasionally be available, in the light of these findings the contention that language input generally incorporates negative information appears to be unfounded.

Child, Preschool↗
PubMed2006

'To define means to say what you know about things': the development of definitional skills as metalinguistic acquisition.

Some authors have suggested that definitional skills include metalinguistic components (Watson, 1985; Snow, 1990; McGhee-Bidlack, 1991). The present study therefore empirically investigated relations between the ability to define words and level of metalinguistic awareness in 280 Italian children (with ages ranging from 5 to 11 years) and in two groups of 40 adults each (with low and high educational levels, respectively). We used a definitional task presenting 24 terms (nouns, verbs, and adjectives, which were either concrete or abstract) and a task examining 6 different aspects of metalinguistic awareness. Our aim was to demonstrate that metalinguistic skills can positively predict the formal quality of definitions and to identify various aspects of metalinguistic skills that might be directly related to definitional skills. Results showed better performance on both tasks as a function of age and educational level; they also confirmed the important roles of metalinguistic ability and educational level in producing well-structured formal definitions.

Adult↗
PubMed1997

Linguistic cues in the acquisition of number words.

Previous research has shown that children go through a stage in which they know that the number words each refer to a distinct numerosity, yet do not know WHICH numerosity each number word picks out (Wynn, 1992). How do children attain this level of knowledge? We explore the possibility that particular properties of how number words are used within sentences inform children of the semantic class to which they belong. An analysis of transcripts of the spontaneous speech of three one- and two-year-old children and their parents (from the CHILDES database; MacWhinney & Snow, 1990) suggests that the relevant cues are available as input in parents' speech to children, and that children generally honour these properties of number words in their own speech. Implications of this proposal for word learning more generally are discussed.

Child Language↗
PubMed1994

Measurement of IgA responses following Norwalk virus infection and other human caliciviruses using a recombinant Norwalk virus protein EIA.

An enzyme immunoassay employing recombinant Norwalk virus capsid protein was evaluated for the measurement of IgA responses. Tests on 23 volunteers and patients known to have been infected with Norwalk virus (NV) showed that 19 developed significant IgA responses, 2 had unchanging levels of IgA and 2 failed to respond. There was no evidence of IgA responses to NV following infection with Hawaii or Snow Mountain-like viruses. Tests on sera from patients involved in outbreaks associated with eating contaminated shellfish suggest that some patients may have been infected with more than one strain of calicivirus. The use of the rNV EIA for measuring IgA and IgG responses in patients involved in a major outbreak of food poisoning affecting hospital staff indicated that the causative agent was probably NV.

Adult↗
PubMed2002

Epidemiology of Sindbis virus infections in Finland 1981-96: possible factors explaining a peculiar disease pattern.

Pogosta disease (PD), an epidemic rash-arthritis occurring in late summer is caused by Sindbis virus (SINV) and is transmitted to humans by mosquitoes. Altogether 2183 PD cases were serologically confirmed 1981-96 in Finland, with an annual incidence of 2.7/100000 (18 in the most endemic area of Northern Karelia). The annual average was 136 (varying from 1 to 1282) with epidemics occurring in August-September with a 7-year interval. Studies on 6320 patients with suspected rubella (1973-89) revealed 107 PD cases. The depth of snow cover and the temperature in May-July seemed to predict the number of cases. The morbidity was highest in 45- to 65-year-old females and lowest in children. Subclinical SINV infections were 17 times more common than the clinical ones. The SINV-antibody prevalence in fertile-age females was 0.6% in 1992; the estimated seroprevalence in Finland is about 2%. Among game animals the tetraonids (black grouse and capercaillie) had the highest seroprevalence (65%) in the epidemic year of 1981.

Adolescent↗
PubMed2001

Evaluation of depth profiling using laser resonant desorption as a method to measure diffusion coefficients in ice.

Diffusion of gases in ice is involved in cloud, snow, and ice core chemistry, but few data exist on the relevant diffusion coefficients. A novel method to measure diffusion coefficients in ice has recently been proposed by Livingston et al. (Anal. Chem., 2000, 72, 5590-5599). It is based on depth profiling of doped ice crystals epitaxially grown on Ru(001) by laser resonant desorption (LRD). Using this method, Livingston et al. obtained a value of the diffusion coefficient of the HCl hydrate in ice at 190 K of about 5 x 10(-11) cm2/s. We argue here that this value is many orders of magnitude higher than what could be expected from literature values, which are not reported in sufficient detail by Livingston et al. We investigate the possibilities that their high value could be due to (1) diffusion in defects in the ice, which would be present in very high concentrations because of the ice growth method; and (2) the fact that diffusion of high concentrations of HCl in ice at 190 K forms an amorphous HCl:H2O solid mixture, where HCl diffusion is fast. We present new infrared spectroscopic data on solid HCl:H2O mixtures that confirm that such mixtures can indeed be formed in an amorphous state at 190 K. Our proposed interpretation is that by depositing large amounts of HCl on epitaxially grown ice, Livingston et al. created a superficial amorphous binary mixture and that fast diffusion of HCl in the ice, possibly accelerated by a high defect density, produced an amorphous HCl:H2O mixture. We conclude that the processes studied by Livingston et al. are different from those involved in the atmospheric and cryospheric sciences, and that their data, obtained by depth profiling using LRD, probably cannot be applied to those fields.

Journal Article↗
PubMed2004

Direct determination of lead isotopes (206Pb, 207Pb, 208Pb) in arctic ice samples at picogram per gram levels using inductively coupled plasma-sector field MS coupled with a high-efficiency sample introduction system.

Adopting strict cleanroom procedures, ice samples from the Canadian High Arctic have been analyzed for Pb concentrations and Pb isotopes (206Pb, 207Pb, 208Pb) using ICP-SMS. The detection limit for Pb (0.06 pg g(-1)) was approximately 2 orders of magnitude lower than the lowest concentration of Pb in the ice samples (range, 4.3-1660 pg g(-1); median, 45 pg g(-1)). Acidification of ice samples with high-purity HNO3 for stabilization purposes contributed only 0.004 pg of Pb g(-1), which is an insignificant source of Pb. Using a new sample introduction system consisting of a heated (140 degrees C) minicyclonic spray chamber and a Peltier cooled condenser (2 degrees C) and by replacing the conventional sample cone with a high-performance cone, signal intensities for Pb were increased by approximately 1 order of magnitude. Thus, it was possible not only to measure Pb isotope ratios directly using ICP-SMS but also to achieve reasonable precision (approximately 0.2%) at low picogram per gram concentrations of total Pb. This precision is comparable to that achievable by thermal ionization mass spectrometry at such low Pb concentrations, but the ICP-SMS requires much less sample volume (approximately 2 mL), needs no sample pretreatment, and therefore is considerably faster and less expensive than the conventional approach. Even though absolute Pb concentrations in two ice samples dating from 1974 and 1852 were very similar (9 and 6 pg g(-1)) their fundamentally different isotopic signature (206Pb/207Pb: 1.169 +/- 0.002 vs 1.147 +/- 0.003) clearly indicates different sources of Pb. The analytical procedures described here, therefore, offer great promise for fingerprinting the predominant sources of atmospheric Pb in polar snow and ice.

Journal Article↗
PubMed1984

Effects of heating on the ion-gating function and structural domains of the acetylcholine receptor.

The ion-gating ability and the protein electrophoretic band patterns of the acetylcholine receptor from Torpedo californica electroplax were examined after receptor-enriched membrane vesicles were progressively heated. The ion translocation function was lost over a temperature range of 40-55 degrees C. Previous results have shown that the stoichiometry of alpha-bungarotoxin binding is not affected by these temperatures, although bound toxin reversibly dissociates within this temperature range, and that toxin binding is irreversibly lost at somewhat higher temperatures [Soler, G., Farach, M.C., Farach, H. A., Jr., Mattingly, J.R., Jr., & Martinez-Carrion, M. (1983) Arch. Biochem. Biophys. 225, 872]. Thermal gel analysis [Lysko, K. A., Carlson, R., Taverna, R., Snow, J., & Brandts, J.F. (1981) Biochemistry 20, 5570], a sodium dodecyl sulfate-polyacrylamide gel electrophoretic procedure which detects thermally induced aggregation of the components of multimeric systems, was applied to heated acetylcholine receptor enriched membranes. This technique suggests two structural domains susceptible to thermal perturbation within the receptor molecule, one consisting of the Mr 50 000 and the two Mr 40 000 subunits and the other consisting of the Mr 60 000 and 65 000 subunits. Heat disrupts molecular events linking agonist binding with ion-channel opening in the acetylcholine receptor molecule.

Animals↗
PubMed2001

129I from the nuclear reprocessing facilities traced in precipitation and runoff in northern Europe.

A huge amount of radioactive 129I has been released into the environment from the nuclear energy industry, atomic weapon tests, and nuclear accidents. In this study, we present weekly and seasonal data on 129I measured in precipitation and runoff of northern Europe during 1998 and 1999. The 129I concentration is at 10(8)-10(9) atoms/L in precipitation and (2-5) x 10(8) atoms/L in runoff water, and it is 3-4 orders of magnitude higher than in the prenuclear era. Snow shows lower 129I concentration than rain, and there is apparently a positive correlation between surface air temperature and 129I. Precipitation chemistry, expressed as the content of Cl, SO4, and NO3 and atmospheric ozone, exhibits weak negative correlation with 129I values. Our 129I data on precipitation suggest significant influence of the northern European atmosphere by the discharges from the nuclear reprocessing facilities at Sellafield and La Hague.

Europe↗
PubMed2004

Atmospheric deposition of polycyclic aromatic hydrocarbons to Atlantic Canada: geographic and temporal distributions and trends 1980-2001.

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants. The semivolatile organic compounds may disperse into the atmosphere by direct input from several sources such as the burning of fossil fuels, from motor vehicle emissions, and forest fires. Once in the atmosphere, they may travel great distances before being deposited to the earth's surface by the scavenging action of rain and snow. Up to 14 PAHs were determined in wet precipitation samples collected monthly from five sites in the four Canadian Atlantic Provinces during 1980-2001. The relatively more volatile PAHs (phenanthrene, fluoranthene, naphthalene, and pyrene) were predominant in the samples. Significant (P < 0.05) spatial variations in the deposition of some PAHs were observed among sites, but there were no consistent geographic patterns. Seasonal patterns were discernible with peak deposition for sigma6&14 PAHs occurring during the colder months of the year (December to March) and coinciding with higher energy consumption for heating and transport. The monthly volume weighed mean concentration for sigma6 PAHs has declined steadily since the mid-1980s at Kejimkujik National Park in southwest Nova Scotia, with a calculated half-life of 6.4 +/- 0.3 years. The maximum annual deposition flux of 20 microg m(-2) yr(-1) reached in 1985 for sigma6 PAHs decreased approximately 1 order of magnitude by the year 2000. The decrease in sigma6&14 PAHs for the region was found to be correlated (P < 0.05) with decreasing sulfate ion concentrations in the precipitation. The implementation of air pollution abatement programs in Canada, the United States, and elsewhere, switching to cleaner sources of energy and improved technology during the pastfew decades is most likely responsible for the observed decline.

Air Movements↗
PubMed2005

Biogeographic provinces of total and methyl mercury in zooplankton and fish from the Beaufort and Chukchi seas: results from the SHEBA drift.

Samples of copepods (Calanus hyperboreus) and arctic cod (Boreogadus saida) were collected along the SHEBA (Surface HEat Budget of the Arctic) drift track, which commenced in the Canada Basin (October 1997) and finished in the Mendeleev Basin (October 1998). Here, we report total mercury (HgT) and CH3Hg concentrations in these biological samples and examine concentration variability along the drift track in the context of trophic variation, inputs from land, spring mercury depletion events (MDEs), and oceanographic provinces. We find background concentrations of HgT in C. hyperboreus as low as 0.02 microg/g (dw), with the Canada Basin samples exhibiting approximately 2-fold higher mercury concentrations than those from the Chukchi Plateau and Mendeleev Abyssal Plain. This east-to-west trend in mercury concentration is punctuated by two and possibly three intervals of elevated mercury (HgT, 0.10-0.12 microg/g (dw); CH3Hg, 0.023-0.028 microg/g (dw)) along the drift track. One interval of elevated HgT and CH3-Hg levels occurred during and shortly after melt. %CH3Hg reached a maximum of 60% during this time period, three times higher than any other time during the drift. This transient rise in C. hyperboreus CH3Hg concentration seems to strongly point to mercury accumulated in snow during MDEs. However, the alignment of elevated mercury samples with oceanographic fronts and the observed regional differences between basins suggest that variation of mercury concentration is primarily a consequence of ocean structure. Given that large animals such as whales selectively forage in regions of higher food concentration such as fronts, recent change in the ice climate of the western Arctic Ocean, perhaps mediated by changes in heat storage, may provide the means to change their exposure to mercury thus explaining observed increases in mercury concentrations in western beluga whales during the 1990s.

Animals↗
PubMed2004

Annual variations of pesticide concentrations in Great Lakes precipitation.

Twenty pesticides and related analytes were measured in 28-day integrated precipitation samples from five U.S. sites in the Integrated Atmospheric Deposition Network (IADN) between 1997 and 2002. Consistent, significant decreases in concentration as a function of time were observed only for p,p'-DDE and p,p'-DDD, while increases in beta-HCH were observed at all sites. Significant annual variations were observed for most analytes at each site with higher concentrations in the summer for current-use pesticides (endosulfan and gamma-HCH) and peaks in the winter for most others. The increased concentrations in the winter are likely the result of the increased scavenging efficiency of snow compared to rain and, for some analytes, higher concentrations in the particulate phase during winter. These seasonal differences appear to account for a large portion of the observed variability in pesticide concentrations in precipitation samples.

Air Pollutants↗
PubMed2005

Polybrominated diphenyl ethers in airborne particulates collected during a research expedition from the Bohai Sea to the Arctic.

In July to September 2003, particulates in the oceanic atmosphere from the Bohai Sea to the high Arctic (37 degrees N to 80 degrees N) were collected aboard a research expedition icebreaker, Xuelong (Snow Dragon), under the 2003 Chinese Arctic Research Expedition Program (CHINARE 2003). These samples were analyzed to elucidate the atmospheric distributions of polybrominated diphenyl ethers (PBDEs) in the North Pacific Ocean and adjacent Arctic region. The levels of 11 PBDE congeners (BDE-28, -47, -66, -100, -99, -85, -154, -153, -138, -183, and -209; the sum was defined as sigma11PBDE) in the oceanic atmosphere of Far East Asia (34-48 degrees N/122-148 degrees E) ranged from 2.25 to 198.9 pg/m3 with a mean of 58.3 pg/m3. BDE-47, -99, -100, and -209 were the dominant congeners in all the samples, suggesting that the widely used commercial penta- and deca-BDE products were the original sources. The PBDE levels exhibited a decreasing trend from the mid- to high-latitudinal regions of the North Pacific Ocean, probably resulting from dilution, deposition, and decomposition of PBDEs during long-range transport of air masses. On the other hand, no apparent geographical pattern of PBDE distribution was observed within the Arctic, attributable to unstable air circulation and strong air mixing. Correlations among the PBDE congeners suggested that air masses collected from the North Pacific Ocean were relatively fresh, whereas those from the Arctic were aged as a result of photodecompoisiton. The higher average level (17.3 pg/m3) of PBDE congeners in the Arctic than those in the adjacent North Pacific Ocean (12.8 pg/m3) or other remote areas reported in the literature was attributed to the impact of the North American continent and temperature effects, which was consistent with the hypotheses of global fractionation.

Air Movements↗
PubMed2005

Seasonal variation in the occurrence of pharmaceuticals in effluents from a sewage treatment plant and in the recipient water.

The occurrence of five pharmaceuticals (ibuprofen, naproxen, ketoprofen, diclofenac, and bezafibrate) in the influent and effluent water of a sewage treatment plant (STP) in the recipient river water and in a drinking water treatment plant (DWTP) located downstream from the STP was followed during three seasons: winter, spring, and summer. In the STP, the elimination of the pharmaceuticals decreased significantly (an average of 25% compared to spring and summer) in wintertime leading to increased concentrations of pharmaceuticals in the effluent water. The total concentration of all the studied pharmaceuticals in the effluent water was 3-5 times higher in wintertime (about 2500 ng L(-1)) than during the other seasons (about 500-900 ng L(-1)). Accordingly, the highest concentrations (up to 129 ng L(-1)) in the recipient river were measured in the wintertime. Pharmaceuticals were carried longer distances downstream from the STP when the river was covered by ice and snow. During a drastic increase in water flow rate (i.e., during snowmelting), a fast transportation of the pharmaceuticals was observed. The DWTP located downstream from the STP produced water that contained about 8 ng L(-1) of ibuprofen and ketoprofen in the winter sample, whereas in spring and summer the studied pharmaceuticals could not be detected in the drinking water. The results show that cold seasons in boreal areas can severely increase the environmental risk of pharmaceuticals and the risk for contamination of drinking water.

Chromatography, High Pressure Liquid↗
PubMed2006

Temporal and spatial trends of organochlorine pesticides in Great Lakes precipitation.

Organochlorine pesticide concentrations in precipitation samples collected from 1997 to 2003 at seven Integrated Atmospheric Deposition Network sites around the Great Lakes are reported. The 28-day volume weighted mean concentrations of several pesticides, including gamma-hexachlorocyclohexane (HCH), endosulfan, hexachlorobenzene, chlordane, and DDE, showed significant seasonal trends. For current-use pesticides (endosulfan and gamma-HCH), their concentrations peaked in late spring to summer just after their agricultural application. For the banned pesticides, higher concentrations were observed in the winter due to their enhanced partitioning to particles and scavenging by snow. Long-term decreasing trends were observed for several pesticides such as gamma-HCH and DDE. On the other hand, beta-HCH showed significant increasing concentrations as a function of time at Brule River, Eagle Harbor, and Sleeping Bear Dunes. Generally, Chicago had the highest concentration of chlordanes, dieldrin, and DDT, indicating that urban areas could be a source for these compounds to precipitation. For gamma-HCH and endosulfans, Point Petre had the highest concentrations due to the application of these pesticides in the surrounding areas.

Fresh Water↗