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At least 865 records · Page 48Linked to original sources
PubMed1999

Penetrating sledding injuries to the lower torso--2 case reports.

Sledding accidents are frequent and vary in severity. Penetrating sledding injuries are uncommon but may be devastating. Snow-racers--sleds with both steering and braking devices--may be associated with an increased rate of injury. The authors present 2 cases of lower-torso penetrating trauma associated with the use of snow-racers. Both cases involved penetration--of the perineum in one case and the inguinal area in the other--by wooden sticks. Both patients recovered fully after prompt surgical intervention. The authors suggest that the absence of a protective panel at the front of the snow-racer may result in the sledder's lower torso being more exposed to objects encountered while sledding. The injuries reported raise concerns about the safety of modern sleds and the possibility that design changes are needed.

Adolescent↗
PubMed2000

Trace element contamination in Antarctic ecosystems.

Data concerning trace element concentrations in both abiotic and biotic components of the Antarctic ecosystems are summarized here to be used as a first background database for pollution detection. Antarctic ancient ice and snow cores have been used to assess past and present-day changes in global atmospheric levels of certain trace elements. Concentrations of Pb, Cd, and Hg in the Antarctic tropospheric cell have varied according to glacial and interglacial periods before humans began to contaminate the atmosphere with these metals. Based on data of Pb concentrations in the Antarctic ancient ice cores and samples of recent snow, most of the Pb in Antarctica is anthropogenic. Moreover, this metal has decreased in recent years as a consequence of the reduced use of leaded gasoline in countries of the Southern Hemisphere. Reliable experimental and field data have indicated, however, that human activity in Antarctica contributes significantly to increasing atmospheric Pb levels in this continent, whereas the environmental impact of other metals such as Cd, Zn, or Hg is restricted to the area a few hundreds of meters about the anthropogenic source. Trace element concentrations in Antarctic abiotic matrixes are generally at ultratrace levels, challenging analytical detection limits and increasing the risk of unwanted contamination. Pb and Hg concentrations in Antarctic snow, surficial soil, air, and marine sediment have been considered as the lowest concentrations ever reported. Conversely, concentrations in Antarctic biota, are comparable to those from polar and temperate areas of the Northern Hemisphere, in particular Cd and Hg. Environmental and biological factors favoring a greater metal accumulation by Antarctic biota are discussed. Growth rate of the organisms and detoxification mechanisms (e.g., metallothioneins, molting cycles) are largely affected by the extreme environmental conditions in Antarctica (water supply, temperature regimen, light availability) that probably interfere with uptake, storage, and excretion of trace elements by organisms. On the other hand, environmental factors such as the upwelling of Cd-rich waters and local volcanism undoubtedly increase the bioavailability of metals in the Antarctic environment. In this context, several Antarctic organisms such as fish, mollusks, lichens, and mosses have been proposed as suitable biomonitors, and their trace element concentrations have been suggested as baselines. Structure and dynamics of Antarctic ecosystems as well as quantifying metal point sources and long-range atmospheric transport require in-depth studies to improve the assessment of human impact in Antarctica.

Animals↗
PubMed2001

Pathological evaluation of venous emboli during total hip arthroplasty.

One of the possible causes of bone cement implantation syndrome during total hip arthroplasty is pulmonary embolism, as has been suggested by a characteristic image seen during transoesophageal echocardiography, the so-called 'Snow Flurry'. However, the nature of the embolic material has not been definitively determined. We studied seven patients undergoing cemented or uncemented total hip arthroplasty. 'Snow Flurry' images were detected in all patients. Blood was aspirated from the right atrium during 'Snow Flurries' and was subjected to pathological examination. Amorphous, eosinophilic, fine granular material was seen in all specimens. The material did not originate from cement. Fat and bone marrow were not detected. The material seen may consist of fine particles of bone ('bone dust') originating from reamed bone.

Adult↗
PubMed1992

[New perspectives of avalanche disasters. Phase classification using pathophysiologic considerations].

This study comprises an analysis of the data on 332 persons totally buried by avalanches in Switzerland between 1981 and 1989. The survival rate was calculated with the aid of a computer-assisted estimation procedure according to Turnbull. The curve pattern was interpreted according to pathophysiological considerations, on the basis of which the time course of the battle for survival was divided into 4 phases: 1) Survival phase: until 15 minutes after burial under the snow masses. The survival probability amounts to 93% and is, thus, higher than so far assumed. Almost all those buried survived this period of the time provided they were not fatally injured and received first aid. 2) Asphyxia phase: duration of burial under the avalanche from 15 to 45 minutes. The probability of survival sank dramatically during this period from 93% to about 25% (fatal kink of the survival probability curve). Those buried under the snow without an air pocket die of acute asphyxia (the point of no return) and the mortality rate reaches its maximum in this phase. 3) Latent phase: the period as from 45 minutes following the avalanche until the time of rescue. This phase is survived only in the presence of an air pocket. With sufficient oxygen reserves and freedom of thoracic movement a "phase of relative safety" occurs, whereby the survival probability diminishes further only slowly. The first deaths due to hypothermia arise after 90 minutes. 4) Rescue phase: from the time of extrication from the snow until arrival in hospital. There is an increased risk of a fatal outcome during the rescue procedure and immediately afterwards through augmented hypothermia.(ABSTRACT TRUNCATED AT 250 WORDS)

Asphyxia↗
PubMed1987

On the threshold radiant exposure for keratitis solaris.

Marked inflammation of the cornea (keratitis solaris) is often observed after exposure to strong solar radiation, especially in high altitudes and snow-covered terrain. Using the action spectrum and the solar spectrum, the radiant exposure causing keratitis solaris was calculated for a horizontal surface. The parameters selected were altitude, season, ozone content and albedo. The radiant exposure of the eye increases approximately 16-fold, comparing terrain without snow-cover and terrain with snow-cover. Radiant exposures in clinically observed cases of keratitis solaris were calculated to range from 1200 to 5600 Jm-2. A discussion on these figures with regard to threshold doses shows a significant difference between long-term exposure to solar radiation and short-term exposure to artificial sources.

Humans↗
PubMed1986

Description of the goose coccidium Eimeria stigmosa (Klimes, 1963), with evidence of intranuclear development.

Oocysts of Eimeria stigmosa isolated from a wild juvenile lesser snow goose (Anser caerulescens caerulescens) were used in experimental infections of laboratory-reared geese. The structure of oocysts is described; a peculiar bumpy surface and a calyx-like thickening around the micropyle are illustrated by scanning electron microscopy. Experimentally infected geese had reduced feed intake and passed blood in their feces. Six days post-inoculation (p.i.) oocysts were passed for about 24 hr. Oocyst production was not increased in dexamethasone-treated geese. Complete sporulation of oocysts occurred after about 3.5 days. Developmental stages in lesser snow geese were occasionally present throughout the intestine, but were concentrated at Meckel's diverticulum, and at foci in the ileum and colon. Meronts were found 2, 3 and 4 days p.i. and gamonts and developing oocysts were observed 4, 5 and 5.5 days p.i. All endogenous stages of E. stigmosa were present in the nucleoplasm of enterocytes, primarily at the apical half of villi. Nuclear hypertrophy occurred in infected cells and nuclei containing gamonts were enlarged up to 4 times their normal size. Mild lesions were observed in the intestine of infected geese. Patent infections were established in lesser snow, Canada (Branta canadensis) and domestic (Anser anser domesticus) geese, but oocysts were not passed by inoculated ducks.

Animals↗
PubMed1995

[Progressive non-inflammatory lesions of the vitreous and intermediate uveitis].

A 77 year old man presented with a decreased vision, quite anterior segments, vitreous haze (++) (cells and flare) OD > OS, snow banks and snow balls at the inferior pars plana, suggesting an intermediate uveitis. Two subTenon injections of steroids were performed on the right eye, with improvement of his right visual acuity from 5 to 10/10. Cells and snow balls disappeared but the vitreous became more fluffy and more organized. Investigations did not demonstrate any systemic disease. The vitreous haze progressed bilaterally and failed to respond to systemic steroids. A year later, visual acuity was limited to hand movements (OD) and remained at 9/10 (OS). The vitreous haze + (OD) and ++ (OS) was extremely fluffy and moderately organized without inflammatory cells. Vitrectomy was performed in both eyes. Non inflammatory fibro-cellular membranes in a dense collagenous network with amorphous precipitates were observed in electron microscopy. One year later, he developed a systemic B-cell lymphoma. This unusual case illustrates the possible evolution of intermediate uveitis in a secondary PVR-like progressive non inflammatory vitreous haze with a particular increase of the amount of collagen fibrils and amorphous precipitates responsible for the fluffy aspect of the vitreous failing to respond to steroids.

Aged↗
PubMed1995

Formation and microbial utilization of amorphous aggregates in the sea: ecological significance.

Amorphous organic particles, ("marine snow"), are thought to play a vital role in the transfer of carbon and energy from the euphotic layers of the ocean to the deep sea bed. These particles are mainly derived from phytoplankton extracellular release. As 10 to 40% of the dissolved organic carbon consists of colloidal material, colloids may represent a prominent role in these transfer processes. These colloids adsorb charged molecules efficiently and can coagulate further to form the recently described transparent exopolymer particles and eventually the ubiquitous macroscopic marine snow. The other mechanism proposed leading ultimately to marine snow formation is inefficient top-down control of phytoplankton growth by zooplankton. In the senesce of the phytoplankton bloom the cell surface becomes sticky due to the release of polysaccharides, and single phytoplankton cells then aggregate. Subsequently these aggregates become densely colonized by auto- and heterotrophic microbes, but while the abundance of these microorganisms is from 2 to 4 orders of magnitude higher than in the ambient water, their growth rates are usually not significantly increased in the aggregates. In this review, the reasons for this conspicuous pattern are discussed and recently investigated novel types of particles and their significance in the light of oceanic carbon transfer are presented.

Colloids↗
PubMed1996

Asphyxial death of a young skier.

OBJECTIVE: Review of the cause of death in fatal downhill skiing accidents is important to prevention: this report concerns a boy found dead with his head buried in powder snow. EXPERIMENTAL DESIGN: Case history of an 11-year-old boy who was found dead 4 hours following descent of a steep ski slope. SETTING: Treatment by mountain rescue team and hospital emergency room. PATIENT: A boy who was discovered immersed head first in one meter of powder snow, with no sign of an avalanche or struggling, and no vital signs. The differential diagnosis included concussion + asphyxia, cervical injury, loss of consciousness from other causes, and hypothermia. INTERVENTIONS: Standard cardio-pulmonary resuscitation, rewarming by bladder irrigation and extracorporeal circulation. RESULTS: The rectal temperature, initially 29.4 degrees C, fell further to 23.3 degrees C during evacuation in a heated ambulance. On hospital admission, a blood sample showed creatine kinase 5306 units, K+ 16 mM, pH 6.38, PaCO2 223 Torr, and PaO2 67 Torr. There was no ECG rhythm, and radiography revealed pulmonary edema but no cervical malignment. Emergency measures normalized blood gases, but did not restore cardiac action. CONCLUSIONS: Death was caused by asphyxia, secondary to mild concussion. The public needs education on the dangers of deep powder snow. Adventurous skiers should wear helmets, and should not ski alone on steep mountainsides.

Asphyxia↗
PubMed1998

Inclement weather and the risk of hip fracture.

An association between inclement weather and hip fractures has been documented, but specific subgroups of the population at particular risk have not been identified. We obtained information that included hospitalization data on all hip fractures in Montreal from 1982 to 1992, and meteorologic data on the amount of snow, rain, and freezing rain and the temperature on each day of study. We used a cross-level design to examine the association between the rate of hip fractures and the meteorologic conditions on the day of the accident in both sexes and five age strata. There were a total of 18,455 hip fractures over the 4,018-day study period. We found a cyclical pattern in occurrence of hip fractures, with the peak occurring in mid-December among women and the first week of January among men. The pattern was less pronounced among women than men, with peak-to-trough ratios of 1.2 and 1.4, respectively. Days with lower temperatures, snow, and freezing rain were associated with increased rates of hip fracture. The meteorologic condition carrying the greatest risk was freezing rain. The association between inclement weather and hip fractures was stronger among younger persons, both women and men. After adjusting for meteorologic variables, there remained increases in winter of 5% among women and 12% among men. The residual effect of winter may be related to cold temperatures or due to an accumulation of ice and snow even on fine days. Other possible mechanisms to explain the residual effect of winter include slower reaction times and winter bone loss, both of which could affect indoor as well as outdoor falls.

Age Factors↗
PubMed1992

Neurite outgrowth on a step gradient of chondroitin sulfate proteoglycan (CS-PG).

Sulfated proteoglycans (PGs) may play a significant role in the regulation of neurite outgrowth. They are present in axon-free regions of the developing nervous system and repel elongating neurites in a concentration-dependent manner in vitro. The addition of growth-promoting molecules, such as laminin, can modify the inhibitory effect of PGs on neurite outgrowth (Snow, Steindler, and Silver, 1990b). Substrata containing a high-PG/low-laminin ratio completely inhibit neurite outgrowth, while normal, unimpeded outgrowth is observed on low-PG/high-laminin substrata. Therefore, different patterns of neurite outgrowth may result from regulation of the ratio of growth-promoting molecules to growth-inhibiting molecules. Using video microscopy, embryonic chicken dorsal root ganglia neurons (DRG), chicken retinal ganglia neurons (RGC), and rat forebrain neurons (FB) were analyzed as they extended processes from a substratum consisting of laminin alone onto a step gradient of increasing concentrations of chondroitin sulfate proteoglycan (CS-PG) bound to laminin. In contrast to neurite outgrowth inhibition that occurs at the border of a single stripe of high concentration of CS-PG (Snow et al., 1990b and this study), growth cones grew onto and up CS-PG presented in a step-wise graded distribution. Although the behavior of the different cell types was unique, a common behavior of each cell type was a decrease in the rate of neurite outgrowth with increasing CS-PG concentration. These data suggest that appropriate concentrations of growth-promoting molecules combined with growth-inhibiting molecules may regulate the direction and possibly the timing of neurite outgrowth in vivo. The different responses of different neuronal types suggest that the presence of sulfated PG may have varying effects on different aspects of neuronal development.

Aggrecans↗
PubMed2005

Biometeorological effects on worker absenteeism.

The effects of six biometeorological variables (temperature, precipitation, air pressure, humidity, wind speed, and snow) on plant-wide worker absenteeism rates were investigated using 4 years of daily absence data (n=889). After holding constant temporal variables (years, season, and day of week), and then other biometeorological variables, all but one of the variables under consideration were uniquely and significantly related to absenteeism: temperature (r(partial)=-0.17***), precipitation (r(partial)=0.12***), air pressure (r(partial)=-0.09**), wind speed (r(partial)=0.11*), and snow (r(partial)=0.30***). Humidity (r(partial)=-00, ns) was not uniquely correlated. The adjusted R(2) of .29 (full R=0.55) for the entire model was also significant, illustrating the importance of these exogenous, meteorological variables in developing a prediction model of plant-wide absenteeism.

Absenteeism↗
PubMed2003

Two types of matter economy for the wintering of evergreen shrubs in regions of heavy snowfall.

Plant adaptation to an environment subject to heavy snowfalls was investigated in four species of evergreen shrubs growing in a Fagus crenata forest in an area of Honshu on the Sea of Japan. These shrubs stored carbohydrates in some organs before the snowy season and were covered with snow for 4-5 months. Aucuba japonica var. borealis, Camellia rusticana, and Ilex crenata var. paludosa maintained a reserve of carbohydrates during the snowy season. In Daphniphyllum macropodum var. humile, the reserve of carbohydrates decreased during winter. The respiration rates in the first three species decreased from autumn to winter, whereas the decrease in D. macropodum was slight. It was found that the first three species could use reserve carbohydrates for the growth of new shoots after the thaw, whereas in the last species the growth of new shoots depends on high photosynthetic activity in late spring. Our findings suggest some types of matter economy in evergreen shrubs for wintering in an environment of heavy snow.

Acclimatization↗
PubMed2006

The influence of snowfall, temperature and social relationships on sleeping clusters of Japanese monkeys during winter in Shiga Heights.

We studied Japanese monkeys (Macaca fuscata) of the Shiga A(1) troop at their sleeping sites in Shiga Heights, Japan, for 41 nights during 3 winters. Monkeys chose their sleeping sites in Japanese cedars and in deciduous broad-leaved forests on non-snowing nights and in Japanese cedar forests on snowing nights. We counted 399 sleeping clusters in which 2 or more monkeys remained in physical contact through the night and 43 solitary sleeping monkeys, though monkeys did not maintain physical contact with others in the daytime. We found 397 clusters on tree branches and 2 clusters on rocks. The mean size of huddling clusters was 3.06+/-1.22 SD. The cluster size (3.17+/-1.26 SD) at lower ambient temperatures between -7 and -4 degrees C was larger than that at higher temperatures between -2 and 4 degrees C (cluster size 2.88+/-1.13 SD). Most clusters were composed of kin. Females kept close to related females in the daytime and huddled with them at night. The highest-ranking male mainly huddled with his kin and his familiar females. Other males kept farther apart from each other in the daytime, probably to avoid social conflicts. Through cold winter nights, however, such males reduced inter-individual distances and huddled with other males. Japanese monkeys appear to recognize three types of inter-individual distances: an intimate distance less than 1 m, a personal distance of 1-3 m and a social distance of 3-20 m; they change their inter-individual distances according to social and ecological circumstances.

Age Factors↗
PubMed2005

RDX and TNT residues from live-fire and blow-in-place detonations.

Snow was used as a collection medium to examine 1,3,5-hexahydro-1,3,5-trinitrotriazine (RDX) and 2,4,6-trinitrotoluene (TNT) residues post-detonation of 60-, 81-, and 120-mm mortar rounds, 105- and 155-mm howitzer rounds, M67 hand grenades, 40-mm rifle grenades, and blocks of C4. Residue-covered snow samples were collected, processed, and analyzed for explosives without cross-contamination from previous detonations and other potential matrix interferences. Detonation trials were performed following standard military live-fire and blow-in-place techniques. When possible, replicate munitions were detonated under similar conditions to provide a more reliable estimation of the mass of unconsumed high explosive residues. Overall the amount of energetic residues deposited from live-fire detonations were considerably less than the energetic residues deposited by blow-in-place detonations.

Environmental Monitoring↗
PubMed2004

Heavy metal pollution and forest health in the Ukrainian Carpathians.

The Ukrainian Carpathians are characterized by high air pollution caused by emissions from numerous industries. We have been monitoring the state of forests in this region since 1989. The highest levels of tree defoliation (>30%) are found close to industrial emission sources and in the upper mountain forests of the Ivano-Frankivsk and Chernivtsi regions. This is caused by a combination of strong anthropogenic influences (pollution, illegal uses, recreation) as well as poor site and climatic conditions. In the Ivano-Frankivsk region, Cd and Mo accumulate in forest soils; Cr, Mo and Zn soil concentrations are higher than their limit levels; and Pb concentrations exceed toxic levels close to industrial areas (10% of the region territory). Local background levels of heavy metals are greatly exceeded in snow close to industrial regions. Analysis of correlation matrices shows that the chemical elements Ba, Cd, Co, Cr, Cu, Mo, Ni, Pb, V and Zn occur at pollution levels in natural ecosystems in the Ukrainian Carpathians. Maximum concentrations of toxic elements occur in the oak forest zone; the most industrially developed area of the region. Toxic heavy metals in the Ukrainian Carpathians forests enter with precipitation and dustfall, then become fixed in soil and accumulate in leaves, needles of vascular plants and mosses. Concentrations of these metals decrease with altitude: highest in the oak forests, less in beech, and lowest in the spruce forest zones. However, some chemical elements have the highest concentrations in spruce forests; V in needles, As in snow, and Ba and Al in soils.

Air Pollution↗
PubMed2002

Injury patterns in skiboarding. A 2-year study in Scotland.

OBJECTIVES: To examine the incidence and patterns of injury associated with skiboarding, a new snow sport whose popularity has increased in recent years. METHODS: A prospective study of all injured skiboarders at Cairngorm, Glenshee and Nevis Range ski areas during the 1999-2000 and 2000-2001 winter seasons. Personal details, skiboarding parameters, diagnosis and treatment were recorded. Random counts were performed to analyse the percentage of skiboarders amongst the on-slope population. RESULTS: The 84 injuries were recorded in 80 individuals. The injury rate for skiboarding was 252 mean days between injury (MDBI). Skiboarders comprised 5% of the total on-slope population. Ligament sprains and fractures accounted for 49 and 36% of all injuries, respectively. Over 70% of all injuries affected the lower limb and 21% of injuries were below knee fractures. The incidence of upper limb injuries was lower than expected at 13% of total. CONCLUSIONS: Skiboarding, whilst not associated with an excess injury rate, has a unique pattern of injury with a higher fracture rate than any other snow sport. The rates of lower limb and upper limb injury may be explained by the use of a non-release binding and inherent differences in the nature of a skiboard fall.

Adolescent↗
PubMed2003

Review of behaviour of oil in freezing environments.

The current knowledge of the physical fate and behaviour of crude oil and petroleum products spilled in Arctic situations is reviewed. The fate and final deposition of oil in marine conditions is presented as based on the extant literature. Spreading models were evaluated for oil on ice, under ice, in snow, in brash ice, and between blocks of ice. Models of oil transport under sheet and broken ice were considered, both for sea and river conditions. The ability of ice sheets to trap oil is discussed in relation to oil storage capacity. The effects of oil on a growing ice sheet were examined, both in terms of ice formation and the thermal effects of oil inclusions in ice. The migration of oil through ice was reviewed, focussing primarily on the movement through brine channels. The effects of oil on the surface of ice were considered, with emphasis on the effects of surface pools on ice melt. Similar consideration was given to the effects of oil on snow on the surface of ice. The few quantitative studies of oil in open and dynamic ice conditions are reviewed. Observations of intentional small-scale spills in leads and ice fields are reviewed and compared with observations from real spills. The conditions under which "oil pumping" from leads occurs were quantified. The most common ultimate fate of oil in an ice field is to be released onto the water surface.

Accidents↗