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PubMed1988

Heavy metal concentrations in urban snow as an indicator of air pollution.

Manganese, Zn, Pb, Cu, Cr and Cd concentrations in snow collected in and around urban areas and from snow dumping stations in Hokkaido were determined by Zeeman-type atomic absorption spectrophotometry. We compared the heavy metal concentrations in the snow with background levels to see whether they could be used as an effective indicator of urban air pollution. The heavy metal concentrations in the snow clearly increased towards the center of the city of Sapporo; they were influenced by local pollution in the industrial area of the city and by the effect of the seasonal wind from the northwest. In the cities, we found the greatest influence on heavy metal concentrations was air pollution caused by industrial activities. The elemental concentrations in urban snow were from several to tens of times higher than background levels. The mean concentrations of the elements studied were in the order Mn greater than Zn greater than Pb greater than Cu greater than Cr greater than Cd, the same as in water except for Pb. We propose that data on trace metal concentrations in snow are a reliable guide to the degree of air pollution, and can be used as a simple and effective indicator of urban air pollution.

Air Pollution↗
PubMed1998

Snow quality in the city of Luleå, Sweden--time-variation of lead, zinc, copper and phosphorus.

The quality of urban snow was studied with regard to how the concentrations of selected metals and phosphorus vary over time. The area studied is situated in northern Sweden (65 degrees 36' N; 22 degrees 13' E). Snow samples were taken at three different locations in the city centre, approximately every second week, throughout winter. This study has clearly shown the importance of local conditions and snow clearance operations on snow quality. The study also shows that it is difficult to interpret and predict the concentrations of lead, zinc, copper and phosphorus in the snow. However, it should be possible to predict the mass loads of these substances from the deposition velocities, if the snow handling methods and routines, as well as the local circumstances are known.

Copper↗
PubMed1999

Snow algae of the Sierra Nevada, Spain, and High Atlas mountains of Morocco.

Snow algae (Chlorophyta) are reported from the Sierra Nevada mountains in southern Spain and the High Atlas mountains of Morocco. Populations of the snow algae Chlamydomonas sp., coloring the snow orange-red, were collected from Pico de Veleta, Spain, while snow samples from Mt. Neltner in the High Atlas mountains, contained resting spores of an orange-green colored Chloromonas sp. Other microbes observed in snow samples include bacteria, fungi, heterotrophic euglenids, diatoms, nematodes, and heterotrophic mastigotes (flagellated protists). This is the first report of snow algae from the Sierra Nevada mountains of Spain and from the Afro-alpine environment.

Altitude↗
PubMed2001

The impact of variable snow pack accumulation on a major Scottish water resource.

In regions such as northern Scotland, where winter temperatures are such that the occurrence of snow is borderline under the present climate, potential changes affecting precipitation and temperature regimes may have a disproportionately large impact on snow processes and hydrological behaviour. The physical characteristics of mountainous areas in Scotland mean that the spatial variability of snowpack accumulation is high, as well as the temporal variability caused by the climate. There have been few modelling studies aimed at assessing the significance of snow resources in these areas and none that have adopted a spatially distributed approach. This paper describes the approach taken in applying a new distributed model to a headwater catchment in the Cairngorm Mountains. The results demonstrate the importance of wind on re-distributing snow to create deep accumulations in small sheltered pockets. These accumulations are shown to be important in sustaining baseflows in the rivers, long after snow has melted from the rest of the catchment. The model has also produced a first set of maps showing how predicted snow depths vary across the catchment through the winter.

Journal Article↗
PubMed1986

IgE sensitization in snow crab-processing workers.

Occupational asthma is a highly prevalent disease among snow crab-processing workers, but its immunologic mechanism has not been identified. Prick skin tests with snow crab-meat extract, commercial extracts from other crab genera, and snow crab cooking water collected in 1984 were performed on 119 workers. Crab-specific IgE was assessed by RAST in sera from 115 workers with meat and water extracts. Both skin and RAST tests were performed in 58 individuals. Diagnosis of occupational asthma had previously been confirmed in 54 individuals. A highly significant relationship was demonstrated between the presence of immediate skin reactivity or increased serum levels of specific IgE to crab extracts and the occurrence of occupational asthma. There was good agreement between the results of skin and RAST tests with extracts of either meat or snow crab cooking water. Cooking water and snow crab-meat extracts were more sensitive than commercial preparations. Water extract was more potent and more sensitive than meat extract. We conclude that there is evidence that occupational asthma in snow crab-processing workers is mediated through an IgE mechanism.

Aerosols↗
PubMed1995

A new perspective on John Snow's communicable disease theory.

When John Snow undertook the studies of the cholera epidemic of 1854 in London, he was testing his theory of communicable disease, which had been enunciated in an oration delivered at the 80th anniversary of the Medical Society of London. Snow had been elected orator of the year for 1853 and, according to his biographer, had spent the better part of a year in preparation. The oration was titled, "On Continuous Molecular Changes, More Particularly in Their Relation to Epidemic Diseases." Although the text of this oration is readily available in the 1936 Commonwealth Fund facsimile reprint of Snow's more famous cholera studies, few modern epidemiologists are familiar with the work. In it, Snow lays out a theory which includes recognition that for each communicable disease there is a distinct and specific cause, that the causal agent is a living organism which is stable over many generations of propagation, that infection is necessary for communication to occur, and that the quantity of infectious material transmitted is increased by multiplication after infection to produce disease manifestations. Although Snow's theory is similar to Jacob Henle's formulations of a decade earlier, it is more precise, more comprehensive, and more explicit. On the basis of this work alone, Snow deserves broader recognition than he has received.

Cholera↗
PubMed2000

Characterization of the microbial community of lotic organic aggregates ('river snow') in the Elbe River of Germany by cultivation and molecular methods.

Aerobic and anaerobic cultivation techniques, 16S rDNA-based phylogeny, and fluorescent in situ hybridization were used to describe the phylogenetic diversity and physiological versatility of lotic microbial aggregates ('river snow') obtained from the river Elbe. In the course of the year the 'river snow' community changed. It was characterized by a great bacterial diversity in spring, the predominant occurrence of algae in summer and reduction of the total bacterial cell count in autumn and winter. In all 'river snow' samples, more than 70% of the bacteria counted with the general DNA stain DAPI also hybridized with the Bacteria-specific probe EUB338. In situ analysis of the bacterial 'river snow' community with a comprehensive suite of specific rRNA-targeted probes revealed population dynamics to be governed by seasonal factors. During all seasons, beta-Proteobacteria constituted the numerically most important bacterial group forming up to 54% of the total cell counts. In contrast to this, the relative abundance of other major bacterial lineages ranged from 2% for the order Planctomycetales to 36% for Cytophaga-Flavobacteria. Cultivation of 'river snow' under aerobic and anaerobic conditions with a variety of different media resulted in the isolation of 40 new bacterial strains. Phenotypic and phylogenetic analyses revealed these new strains to be mostly unknown organisms affiliated to different bacterial phyla. Application of newly developed specific oligonucleotide probes proved the cultivated bacteria, including clostridia and the numerically abundant beta-Proteobacteria, as relevant in situ members of the 'river snow' community.

Journal Article↗
PubMed1992

Effect of age and coronary artery disease on response to snow shoveling.

OBJECTIVES: The objective of this study was to evaluate the effect of age and coronary artery disease on responses to snow shoveling. BACKGROUND: Little information is available on the hemodynamic and metabolic responses to snow shoveling. METHODS: Sixteen men with asymptomatic coronary artery disease and relatively good functional work capacity, 13 older normal men and 12 younger normal men shoveled snow at a self-paced rate. Oxygen consumption, heart rate and blood pressure were determined. In nine men with coronary artery disease left ventricular ejection fraction was evaluated with an ambulatory radionuclide recorder. RESULTS: Oxygen consumption during snow shoveling differed (p < 0.05) among groups; it was lowest (18.5 +/- 0.8 ml/kg per min) in those with coronary artery disease, intermediate (22.2 +/- 0.9 ml/kg/min) in older normal men and highest (25.6 +/- 1.3 ml/kg/min) in younger normal men. Percent peak treadmill oxygen consumption and heart rate with shoveling in the three groups ranged from 60% to 68% and 75% to 78%, respectively. Left ventricular ejection fraction and frequency of arrhythmias during shoveling were similar to those during treadmill testing. CONCLUSIONS: During snow shoveling 1) the rate of energy expenditure selected varied in relation to each man's peak oxygen consumption; 2) older and younger normal men and asymptomatic men with coronary artery disease paced themselves at similar relative work intensities; 3) the work intensity selected represented hard work but was within commonly recommended criteria for aerobic exercise training; and 4) arrhythmias and left ventricular ejection fraction were similar to those associated with dynamic exercise.

Adult↗
PubMed1999

Forced copulation results in few extrapair fertilizations in Ross's and lesser snow geese.

Extrapair paternity varies from 0 to over 70% of young among various populations of birds. Comparative studies have suggested that this variation is related to nesting density, breeding synchrony and the proportion of extrapair copulations. We used minisatellite DNA fingerprinting to examine levels of extrapair paternity in Ross's geese, Chen rossi, and lesser snow geese, C. caerulescens c. (hereafter snow geese) nesting in the largest known goose colony in the world. These geese have one of the highest known percentages of extrapair copulation (46-56% of all attempted copulations), and all of these appeared to be forced. Among all successful copulations, 33 and 38% were extrapair in Ross's and snow geese, respectively. Despite the high percentage of extrapair copulations, extrapair paternity was low in both Ross's and snow geese (2-5% of young). Extrapair paternity was not related to nest density in either species. However, in snow geese, extrapair paternity was more likely to occur in nests of females that nested asynchronously, either early or late in the season. This is one of a few reported examples of a negative relationship between extrapair paternity and breeding synchrony. Extrapair young also tended to come from eggs laid later in the clutch. Although forced extrapair copulations appear to be a relatively inefficient reproductive tactic for males, they may provide a reproductive advantage for some males. Copyright 1999 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1996

An Attempt to Interpret the Spread of Element Concentration in Antarctic Surface Snow: The Same Element in a Given Test Field, Several Elements in Different Sampling Fields

Sampling surface snow on a large test field always leads to a spread of analyte concentration data which partly follows a Gaussian distribution and partly a rectangular one as can be observed from the analysis of literature data. The spread depends on the nonuniformity of the air-snow interface in the field and on the extent of reproducibility of all the procedures used from sampling to analysis. Consequently a sample relevant to a restricted surface might be poorly representative of the surrounding area. Contamination of the sample during the gathering and storing steps is assumed to be the main source of nonrandom results (outliers). Using various statistical tools we were able to evaluate which part of the spread was due to the snow surface nonuniformity in the case of many samples collected in the same test field. In the case of samples gathered in different geographical areas, the possibility of finding correlations among points is greatly enhanced when three or more analytes are considered for each sample. When the same correlation is found for some analytes and a variable tentatively tested, information can be gained about the source of chemical content of snow samples. The use of UV pretreatment of snow samples has been proven to cut down the interference of organics on the electrochemical process in DPASV, allowing one to obtain accurate and reproducible data.

Journal Article↗
PubMed1999

Models to Assess the Risk of Snow and Wind Damage in Pine, Spruce, and Birch Forests in Sweden.

/ Each year damage to forests caused by snow and wind causes high economic losses. In Sweden, approximately 4 million m3 are damaged annually by snow and wind, roughly corresponding to a value of US$150 million, and in Europe, the damage amounts to hundreds of millions of US dollars each year. To help to reduce these losses, tools for risk assessment within forest management have been developed. Predictions were developed of the risk of damage from snow and wind to Scots pine (Pinus sylvestris L.), Norway spruce [Picea abies (L.) Karst.] and Birch (Betula spp. L.) plots using tree, stand, and site characteristics. The data were obtained from 6756 permanent sample plots within the Swedish National Forest Inventory, which were inventoried twice at five-year intervals between 1983 and 1992. Input data for model development used measurements from the first inventory of tree characteristics for the largest sample tree, stand, and site data, and records of snow and wind damage from the second inventory. Models were developed for three different regions for pine- and spruce-dominated sites, while models for the whole country were developed for birch sites. In general the estimated proportion of damaged plots was highly overestimated (31.7%-56.2%), compared with the observed proportion of 3.4%-11.9%. The models for Norway spruce comprising tree, stand, and site data show the best predictability of damaged plots, with 60.6%-67.6% of plots correctly classified. It is concluded that the models developed can be used to detect sites with a high probability of damage from snow and wind, and thus be used as tools to reduce future damage and costs in practical forestry.KEY WORDS: Birch; Norway spruce; Risk assessment; Risk management; Scots pine; Silviculturehttp://link.springer-ny.com/link/service/journals/00267/bibs/24n2p209.html

Journal Article↗
PubMed1995

[John Snow (1813-1858): experimental studies on rebreathing of anesthetic gases in exhaled air].

As early as in 1850 (only 4 years after the first clinical performance of ether anaesthesia by W. T. G. Morton on 16 October 1846) John Snow recognised that ether and chloroform were exhaled unchanged with the expired air. To reuse these unchanged vapours in the following inspiration and thereby prolonging the narcotic effect of a given amount of anaesthetic vapour, he converted his ether inhaler into a To-and-Fro Rebreathing System: The apparatus was equipped with a facemask without an expiratory valve and a large reservoir bag containing pure oxygen; an aqueous solution of caustic potash was used as CO2 absorbent. In several experiments, performed on himself, Snow succeeded to demonstrate that rebreathing of the exhaled vapours was possible following carbon dioxide absorption, and that it resulted in a pronounced prolongation of the narcotic effects of the volatile anaesthetics. Furthermore, Snow performed experiments on animals using a closed system for evaluating the carbon dioxide production during anaesthesia. It is all the more worthwhile to introduce Snow's publications on these topics, as, despite their extraordinary theoretical and practical significance, they remained nearly unnoticed. Even in the fundamental articles by D. Jackson and R. Waters, both being the respected protagonists of the rebreathing technique in anaesthesia, the Snow papers remained uncited.

Anesthesia, Closed-Circuit↗
PubMed2000

John Snow: the first hired gun?

The 1854 English cholera outbreak led to reform of Victorian public health legislation, including the Nuisances Removal and Diseases Prevention Act. The reforms threatened the closure of many factories whose fumes were considered hazardous to the public's health. The second witness to appear before the Parliamentary committee considering the reforms was Dr. John Snow. Snow testified on behalf of the manufacturers threatened by the reforms. He stated that the fumes from such establishments were not hazardous. He contended that the workers in these factories did not become ill as a result of their exposures, and therefore these fumes could not be a hazard to the general public's health. Snow also presented data from the 1854 cholera outbreak as the basis for his belief that epidemic diseases were transmitted by water, not air. Although the data concerned cholera, Snow extended the inference to all epidemic diseases. When the committee's report was published, The Lancet chastised Snow in a stinging editorial. Parliament subsequently revised the bill in favor of the manufacturers and passed it into law. The implications of this particular episode in the history of epidemiology are discussed.

Cholera↗
PubMed1999

Structure/function/activity relationships in marine snow. Current understanding and suggested research thrusts.

Marine snow and marine snow components contribute to the mucilage phenomenon in the northern Adriatic Sea. Of special relevance is the matrix material, composed of extracellular polymeric substances, which are packaged into fibrils of colloidal dimensions. These 0.005 micron diameter fibrils are physical units of mucilage which can be visualized by transmission electron microscopy (TEM). They form polymer bridges between the various biotic and mineral components of marine snow, creating three-dimensional networks which affect floc porosity, density and settling behaviour. Recent observations of the matrix by TEM reveal complex fibril-delimited channels and capillary systems which partially traverse marine snow flocs and which are postulated to play roles in anomalous settling. Considering the marine snow floc as a microecosystem, the relationships between ultrastructure, chemistry and environmental properties are being explored. On the assumption that colloidal matrix materials, including those released into the bulk water, might provide advance information on anomalous floc behaviour, two new methods are recommended for monitoring the northern Adriatic Sea. One is a technique for chemical quantification of colloidal organic carbon. The other uses TEM, applied to water fractions derived from cascade ultracentrifugation, to estimate fibril quantities as a proportion of colloidal organic carbon.

Chemical Phenomena↗
PubMed1992

[Snow-white in danger. Women, socialization and health. Some messages, by means of allegory].

This is the modern-day allegory of Snow White, the most beautiful woman in the kingdom. Because of her beauty she is banished from the castle. The seven dwarfs who befriend her welcome her into their cottage. Little by little, they begin to impose their demands on her. They try to coerce her into submitting to life's little demands in order to attain beauty, health and happiness. Diet categorizes the foods filled with nasty calories that Snow White must learn to do without. Fitness outlines her spare time exercise regimen to keep her slim and trim. Mr. Clean provides her with specific household cleaning tips. Job tips advise her how to get a job outside the home to maintain her financial autonomy. Pills provide her with a way to assure a smooth transition between work and the household chores. Oh! And we almost forgot Baby. Who will care for Baby? Snow White of course--since she is the only woman in the house. Finally, to assure perfect co-ordination of all these tasks, Excel sends her off to take a time management course. Snow white responds enthusiastically to all the expectations. As anticipated, she loses weight. She then becomes exhausted and collapses and is transformed into Burnt-Out Beauty. She remains in a deep sleep for 100 days and nights. The dwarfs place her in a glass box in a forest clearing where she is discovered by Prince Conscience. He opens the glass box, kisses her lightly on the forehead, and immediately disappears. Snow White awakens and remembers the events preceding her deep sleep.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMedDate not supplied

Hand injuries from snow blowers: a report of an epidemic.

During a record snowfall in Worcester, Massachusetts, 11-13 December 1992, 37 male patients with hand injuries suffered during snow blower operation were seen at three area hospitals. Two previous reports describe 13 patients seen over a 3-year period and 28 patients over a 12-year period. This report describes the largest number of hand injuries from snow blowers that have occurred over a 48-hour period. The snow was unusual because of the high water density in the initial 9 inches (23 cm) that fell at an average temperature of 33 degrees F (0.6 degree C) with the final depth of 30 inches (76 cm), causing the machines to become clogged. Patients admitted to reaching into a running machine in 35/37 (95%) cases, 11/37 (30%) claimed the auger and impeller blades were disengaged, and 2/37 (5%) patients claimed their injuries occurred with the engines turned off. All injuries occurred when the patients placed their hands down the chute, contacting the impeller blades. Injuries involved 32 long, 15 ring, 13 index, and five small fingers and ranged from simple lacerations to partial phalangeal amputations. The majority, 27/37 (73%), were managed in emergency departments without interventions in the operating suites. Infection occurred in one patient who had the lesion repaired in the operating suite. As in previous studies, no differences were found for the variables of snow-blower age, type, or horsepower, or on experience level or age of the operators.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed2026

A chromosome-level assembly of the alpine snow alga Chloromonas typhlos.

Chloromonas typhlos is a cosmopolitan alpine snow alga distributed across continents, and its blooming accelerates snow melting by decreasing the amount of snow albedo. To elucidate the genetic traits underlying the adaptation of C. typhlos to the alpine habitat, we combined PacBio sequencing and Hi-C to generate a high-quality chromosome-level genome assembly (contig N50: 1.29&#x2009;Mb; scaffold N50: 7.23&#x2009;Mb) with 31 chromosomes and a genome size of 200.86&#x2009;Mb. Repetitive elements constituted 11.05% of the genome, and 16,133 protein-coding genes were predicted, of which 82% were functionally annotated. This study provides a set of omics resources both for snow algae and the genus Chloromonas.

Snow↗
PubMed1979

[Studies on medico-legal diagnosis in cold district. 5. The blood shed on the snow (author's transl)].

By using bovine blood as a model, the authors have observed the forms and patterns of the blood drops shed or spurted on the snow and the extent of a large amount of blood absorbed in the deep snows, investigating the influence of the properties of snow upon them. It has been demonstrated that the polarographic method is most excellent for the purpose of determining the amount of blood absorbed in the snow.

Animals↗