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PubMed2003

The hidden dangers of winter sliding.

One of the irresistible allures of freshly fallen snow is the urge to flop onto the ground and slide downhill. Generations of families have been coming together to go sledding for centuries. Unfortunately, this perceived innocuous activity has predictable injury patterns, many of which are preventable with minimal effort or expense. Catastrophic injuries, not infrequently involving younger children, also seem to be preventable with education of the parents and the general public. The current authors reviewed the available literature on sledding injuries and summarized the findings on injury patterns and the recommendations on injury prevention. Proposals for injury prevention and public education, several of which have been designed by national interest groups, are included.

Accident Prevention↗
PubMed2005

The relative role of winter and spring conditions: linking climate and landscape-scale plant phenology to alpine reindeer body mass.

The relative importance of winter harshness and early summer foraging conditions are of prime interest when assessing the effect of global warming on Arctic and mountainous ecosystems. We explored how climate and vegetation onset (satellite-derived normalized difference vegetation index data) determined individual performance in three reindeer populations (data on 27814 calves sampled over 11 years). Snow conditions, spring temperatures and topography were the main determinants of the onset of the vegetation. An earlier onset positively affected the body mass of calves born the following autumn, while there was no significant direct negative impact of the previous winter. This study underlines the major impact of winter and spring climatic conditions, determining the spring and summer food availability, and the subsequent growth of calves among alpine herbivores.

Animals↗
PubMed2002

Cryptococcus nyarrowii sp. nov., a basidiomycetous yeast from Antarctica.

In December 1997, 196 soil and snow samples were collected from Vestvold Hills, Davis Base, Antarctica. Two isolates, CBS 8804T (pink colonies) and CBS 8805 (yellow colonies), were shown by proteome analysis and DNA sequencing to represent the same species. Results from the sequencing of the D1/D2 region of the large rDNA subunit placed this species in the hymenomycetous tree in a unique sister clade to the Trichosporonales and the Tremellales. The clade consists of Holtermannia corniformis CBS 6979 and CBS strains 8804T, 8805, 8016, 7712, 7713 and 7743. Morphological and physiological characteristics placed this species in the genus Cryptococcus, with characteristics including the assimilation of D-glucuronate and myo-inositol, no fermentation, positive Diazonium blue B and urease reactions, absence of sexual reproduction and production of starch-like compounds. Fatty acid analysis identified large proportions of polyunsaturated lipids, mainly linoleic (C18:2) and, to a lesser extent, linolenic (C18:3) acids. On the basis of the physiological and phylogenetic data, isolates CBS 8804T and CBS 8805 are described as Cryptococcus nyarrowii sp. nov.

Antarctic Regions↗
PubMed2002

A throughfall collection method using mixed bed ion exchange resin columns.

Measurement of ionic deposition in throughfall is a widely used method for measuring deposition inputs to the forest floor. Many studies have been published, providing a large database of throughfall deposition inputs to forests. However, throughfall collection and analysis is labor intensive and expensive because of the large number of replicate collectors needed and because sample collection and chemical analyses are required on a stochastic precipitation event-based schedule. Therefore we developed and tested a throughfall collector system using a mixed bed ion exchange resin column. We anticipate that this method will typically require only one to three samplings per year. With this method, bulk deposition and bulk throughfall are collected by a funnel or snow tube and ions are retained as the solution percolates through the resin column. Ions retained by the resin are then extracted in the same column with 2 N KCl and analyzed for nitrate and ammonium. Deposition values in throughfall from conventional throughfall solution collectors and colocated ion exchange samplers were not significantly different during consecutive 3- and 4-month exposure periods at a high (Camp Paivika; >35 kg N ha(-1) year(-1)) and a low deposition (Barton Flats; 5-9 kg N ha(-1) year(-1)) site in the San Bernardino Mountains in southern California. N deposition in throughfall under mature pine trees at Camp Paivika after 7 months of exposure was extremely high (87 and 92 kg ha-1 based on the two collector types) compared to Barton Flats (11 and 13 kg ha(-1)). A large proportion of the N deposited in throughfall at Camp Paivika occurred as fog drip, demonstrating the importance of fog deposition as an input source of N at this site. By comparison, bulk deposition rates in open areas were 5.1 and 5.4 kg ha(-1) at Camp Paivika based on the two collector types, and 1.9 and 3.0 kg ha(-1) at Barton Flats.

Ammonia↗
PubMed2004

Concentrations of atmospheric sulfur compounds in an extremely snowy region, the Hokuriku District, Japan.

The diurnal and seasonal characteristics in gaseous sulfur dioxide and sulfate in aerosol particles, as well as the concentrations of sulfate in rain and snow, were measured in the Hokuriku District, Japan in order to investigate the spatial spread pattern of sulfur compounds and identify the origin of sulfur. The concentration of sulfur dioxide showed a distinct diurnal pattern, while the concentrations of nss-SO4(2-) in precipitation and aerosol particles did not. These results implied that the sulfur dioxide might originate in local emissions and did not affect the concentration of nss-SO4(2-) in precipitation, while nss-SO4(2-) in aerosol particles seemed to be widespread and might result from long-range transportation. The deposition of nss-SO42- in precipitation increased in winter, while the concentration of nss-SO4(2-) in aerosol particles decreased. This could be attributed to the lower cloud base often observed in this district in winter associated with a higher washout ratio.

Aerosols↗
PubMed1971

The inotropic and chronotropic effects of catecholamines on the dog heart.

1. The chronotropic and inotropic responses of the denervated dog heart to intravenous infusions of noradrenaline, adrenaline and isoprenaline were studied.2. The maximum rate of rise of pressure in the left ventricle of the heart, (dP/dt max) measured at a constant heart rate and mean systemic arterial pressure during each series of infusions, was used as an index of inotropic changes (Furnival, Linden & Snow, 1970).3. The order of potency of the catecholamines in producing both chronotropic and inotropic effects was isoprenaline > adrenaline > noradrenaline.4. For the same increase in heart rate produced by an infusion of a catecholamine, noradrenaline caused a greater inotropic effect than adrenaline, which in turn caused a greater increase than isoprenaline.5. The chronotropic and inotropic effects of noradrenaline were potentiated by an intravenous injection of cocaine HCl (5 mg/kg), whereas those of isoprenaline were unchanged.6. The relative difference between the responses to noradrenaline and isoprenaline was abolished by an intravenous injection of cocaine HCl.7. It is concluded that the different relative chronotropic and inotropic effects of isoprenaline and noradrenaline are due to the greater uptake of noradrenaline by sympathetic nerve endings in the sinu-atrial node than in the muscle of the left ventricle.

Animals↗
PubMed1977

The morphology of spinocervical tract neurones revealed by intracellular injection of horseradish peroxidase.

1. The morphology of physiologically identified spinocervical tract neurones was studied using the intracellular injection of horseradish peroxidase in anaesthetized cats.2. Thirty-six spinocervical tract neurones were reconstructed from serial sections of the lumbosacral spinal cord, cut in either the transverse or longitudinal planes.3. Horseradish peroxidase provided a more complete picture of the dendrites of spinocervical tract neurones than earlier experiments using Procion Yellow injection (Brown, House, Rose & Snow, 1976a). The longitudinal (rostro-caudal) spread of dendrites from an individual cell was much greater in the present material; neurones in the medial parts of the dorsal horn had dendrites extending for about 500 mum from the soma (1 mm total spread) and neurones in the lateral horn had dendrites extending for about 1 mm from the soma (2 mm total spread). However, the conclusions of the earlier work, on the medio-lateral and dorso-ventral extents of dendritic trees, together with the shapes of dendritic trees viewed as reconstructions in the transverse plane, have been confirmed. Dendrites of spinocervical tract cells barely entered lamina II of Rexed: they often ran in the longitudinal direction along the border between laminae II and III for several hundred mum. Dendritic spines were observed on many spinocervical tract neurones.4. Horseradish peroxidase reaction product stained up to 2.5 cm of the axon of spinocervical tract neurones. Axons usually pursued a tortuous path through the grey matter close to the cell body, giving off up to six collaterals before entering the ipsilateral dorsolateral funiculus. In the funiculus, further collaterals often arose at distances of up to 5.5 mm from the soma; these collaterals ran back into the dorsal horn. Collaterals could be traced sometimes to presumed terminal boutons. The majority of collateral terminal arborizations was between the level of the cell body and 500 mum ventral to it (in laminae IV and V). They were, however, in the same medio-lateral and rostro-caudal region as the dendritic tree of the parent cell.5. It is concluded that the spinocervical tract must now be considered as having a segmental function, in addition to its function of forwarding information towards the cerebral cortex.

Animals↗
PubMed2005

Warming of the Eurasian landmass is making the Arabian Sea more productive.

The recent trend of declining winter and spring snow cover over Eurasia is causing a land-ocean thermal gradient that is particularly favorable to stronger southwest (summer) monsoon winds. Since 1997, sea surface winds have been strengthening over the western Arabian Sea. This escalation in the intensity of summer monsoon winds, accompanied by enhanced upwelling and an increase of more than 350% in average summertime phytoplankton biomass along the coast and over 300% offshore, raises the possibility that the current warming trend of the Eurasian landmass is making the Arabian Sea more productive.

Asia↗
PubMed2000

Prometheus: Io's wandering plume.

Unlike any volcanic behavior ever observed on Earth, the plume from Prometheus on Io has wandered 75 to 95 kilometers west over the last 20 years since it was first discovered by Voyager and more recently observed by Galileo. Despite the source motion, the geometric and optical properties of the plume have remained constant. We propose that this can be explained by vaporization of a sulfur dioxide and/or sulfur "snowfield" over which a lava flow is moving. Eruption of a boundary-layer slurry through a rootless conduit with sonic conditions at the intake of the melted snow can account for the constancy of plume properties.

Cold Temperature↗
PubMed1981

Aetiology of spheroidal degeneration of the cornea in Labrador.

To determine the aetiology of spheroidal degeneration of the cornea (Labrador keratopathy), total population surveys were conducted in 5 communities in coastal Labrador and northern Newfoundland. For 4 years records were also kept on all clinic patients aged 40 or more throughout the region. Both methods gave a peak prevalence at latitudes 55 degrees--56 degrees north. The greatest severity and earliest age of onset occurred around the same latitudes. Of the proposed environmental causative agents only ultraviolet radiation, reflected from ice and snow, explains the distribution of the disease. The high cumulative UV dosage is due to the unique geographical and climatic features of the region.

Adult↗
PubMedDate not supplied

Helicopter skiing wrist injuries. A case report of "bugaboo forearm".

Of the 42 skiers, 5 (11.9%) experienced symptoms of intersection syndrome early in their week of powder skiing. According to the mountain guides employed by the helicopter service, this overuse injury is quite common and does not represent an unusual incidence for this group of skiers. The mechanism of injury is likely repetitive dorsiflexion and radial deviation of the wrist against the resistance of deep snow on withdrawal of the planted ski pole. Interestingly, the more advanced competitive alpine skiers appeared to be most at risk, possibly because of their more aggressive pole plants. Preventive measures should include instruction in proper pole technique for powder skiing, avoidance of pole dragging and deep pole plants, and downsizing baskets from the standard 4-inch diameter to 2.5-inches and pole length 2 inches shorter than the recommended length for that skier. Once symptoms occur, switching to a different diameter grip, using the pole strap, nonsteroidal antiinflammatory medications, ice, taping of the thumb and wrist, and night splinting appear to offer some relief. Surgical treatment as described by others. is generally successful for those who fail conservative treatment.

Adult↗
PubMed2003

The Cresta Run: a uniquely evolving tradition.

The Cresta Run is a unique toboggan run and exists in only one place in the world, namely, St. Moritz, Switzerland. The height of the resort is over 6,000 feet (1828 metres). Therefore there is a diminution of oxygen content in the air. Normally it takes from three to seven days for a person from lower habitat altitudes, visiting the resort, to become fully acclimatized if they are to be involved in energetic competitive sport. The age and fitness of the toboggan rider is a factor. The Cresta Run takes place each year and has, since its inception under the auspices of the St Moritz Tobogganing Club, been built from virgin snow to a formula determined by a brilliant 22-year-old Swiss geometrician, Peter Bonorand, who devised the first Run in 1884. Using his exceptional mathematical knowledge to determine a course from St. Moritz to Celerina, he drew up plans and drawings for the first Cresta Run. The Run therefore is constructed to a known formula and it is significant that in over 115 years the times on the Run have only improved on average by a few tenths of a second progressively each year despite improvements to riding equipment. Since the Run's inception in 1885 there has always been an element of danger, but accidents have invariably occurred on the section of the Run that comprises the competition course between the start line and the finish line. During the past few seasons, an increasing number of accidents have taken place after the finish line. The problem is short-term blackout while riding (Reader, 1978). There is now a need to investigate what changes have been made or have evolved to cause this. However, certain immutable facts have remained constant and these must be identified and then considered in the context of recent changes as a result of improvements in equipment. Considerable improvements have been made over the past 25 years to safety helmets. These are the result of different materials, their suitability and ease of manufacture, particularly with regard to the full-face type helmet. The full-face helmet could be a significant contributing factor to the problem of accidents, particularly after the finish line, on the Cresta Run.

Accident Prevention↗
PubMedDate not supplied

Hydrologic behavior of two engineered barriers following extreme wetting.

Many engineered barriers are expected to function for hundreds of years or longer. Over the course of time, it is likely that some barriers will experience infiltration to the point of breakthrough. This study compares the recovery from breakthrough of two storage-evapotranspiration type engineered barriers. Replicates of test plots comprising thick soil and capillary-biobarrier covers were wetted to breakthrough in 1997. Test plots were kept cleared of vegetation to maximize hydrologic stress during recovery. Following cessation of drainage resulting from the wetting irrigations, water storage levels in all plots were at elevated levels compared with pre-irrigation levels. As a result, infiltration of melting snow during the subsequent spring overloaded the storage capacity and produced drainage in all plots. Relatively rapid melting of accumulated snowfall produced the most significant infiltration events each year during the study. Capillary barriers yielded less total drainage than thick soil barriers. By limiting drainage, capillary barriers increased water storage in the upper portions of the test plots, which led to increased evaporation from the capillary barrier plots compared with thick soil plots. Increased evaporation in the capillary barrier plots allowed more water to infiltrate in the second season following the wetting tests without triggering drainage. All thick soil plots again yielded drainage in the second season. Within two years of intentionally induced breakthrough, evaporation alone (without transpiration) restored the capability of the capillary barrier covers to function as intended, although water storage in these covers remained at elevated levels.

Environmental Pollution↗
PubMed2006

Current and future water issues in the Oldman River Basin of Alberta, Canada.

Long-term trends in alpine and prairie snow pack accumulation and melt are affecting streamflow within the Oldman River Basin in southern Alberta, Canada. Unchecked rural and urban development also has contributed to changes in water quality, including enhanced microbial populations and increased waterborne pathogen occurrence. In this study we look at changing environment within the Oldman River Basin and its impact on water quality and quantity. The cumulative effects include a decline in net water supplies, and declining quality resulting in increased risk of disease. Our data indicates that decreases in the rate of flow of water can result in sedimentation of bacterial contaminants within the water column. Water for ecosystems, urban consumption, recreation and distribution through irrigation is often drawn from waterholding facilities such as dams and weirs, and concern must be expressed over the potential for contaminate build-up and disproportionate potential of these structures to pose a risk to human and animal health. With disruption of natural flow rates for water resulting from environmental change such as global warming and/or human intervention, increased attention needs to be paid to use of best management practices to protect source water supplies.

Alberta↗
PubMedDate not supplied

The storm of the century. How some hospitals survived it.

The March snowstorm that hit Alabama is already the stuff of legend. It paralyzed businesses and travel, and left people trapped indoors wondering if the white stuff would ever melt. Hospitals were not immune to these problems, but the brave men and women who make Alabama's medical facilities what they are persevered and were there when their communities needed them. These are the responses we received from our call for snow stories and the heroes who kept the hospitals going.

Alabama↗
PubMed2001

[Elevation distribution of precipitation chemistry in middle/upper troposphere in summer, the northern slope of central Himalayas].

During 1997 summer, fresh snow samples were collected from four snowfall events from the elevation of 5800 to 7000 m in the Dasuopu Glacier region on the northern slope of Mt. Xixabangma (28 degrees 33'N, 85 degrees 44'E), in order to understand the elevation distribution of the middle/upper tropospheric components in the remote region. The correlation between SO4(2-), NO3-, Ca2+ and Mg2+ in precipitation differs with type of air mass, indicating the dominant sources of ions vary in short-term (e.g. several days) during summer low dust period. In general, with elevation increases, the concentrations of NO3-, Ca2+ and Mg2+ decreases, while SO4(2-) increases, which are influenced by the variation of dominant sources of ions.

Air Pollutants↗
PubMed2001

Runoff of faecal microorganisms and nutrients from perennial grass ley after application of slurry and mineral fertiliser.

Perennial grass was fertilised with cattle slurry either surface-spread or injected into the soil. Slurry was spread once (early summer) in 1996 and 1997 and twice (both summer and autumn) in 1998 and 1999. The control was mineral fertilisation in summer. Faecal microbial numbers in surface runoff water were very high in late June 1998 soon after very heavy rains even though the last slurry application had been made almost one year earlier. There was no clear difference between slurry spreading methods. Autumn spreading of slurry lead to high microbial levels in runoff waters and water hygiene was protected better by slurry injection than by surface spreading. In spring, after snow melt, some faecal microorganisms were found in surface runoff water and the numbers of faecal microorganisms were less from plots with slurry surface spreading than those with slurry-injection. Losses of total phosphorus (TP) and total nitrogen (TN) in surface runoff were 2.7 and 7.7 kg/ha respectively from grass with surface-spread slurry in winter 1998-1999. The injection of slurry decreased TP and TN runoff by an average of 81% and 73% respectively. In 1999 there was little runoff because the summer was sunny and dry.

Agriculture↗