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At least 1,063 records · Page 59Linked to original sources
PubMed2004

Historical record of European emissions of heavy metals to the atmosphere since the 1650s from alpine snow/ice cores drilled near Monte Rosa.

Cr, Cu, Zn, Co, Ni, Mo, Rh, Pd, Ag, Cd, Sb, Pt, Au, and U have been determined in clean room conditions by inductively coupled plasma sector field mass spectrometry and other analytical techniques, in various sections of two dated snow/ice cores from the high-altitude (4450 m asl) glacier saddle Colle Gnifetti, Monte Rosa massif, located in the Swiss-Italian Alps. These cores cover a 350-year time period, from 1650 to 1994. The results show highly enhanced concentrations for most metals in snow/ice dated from the second half of the 20th century, compared with concentrations in ancient ice dated from the 17th and 18th centuries. The highest increase factors from the pre-1700 period to the post-1970 period are observed for Cd (36), Zn (19), Bi (15), Cu (11), and Ni (9), confirming the importance of atmospheric pollution by heavy metals in Europe. Metal concentrations observed in Colle Gnifetti snow around 1980 appear to be quantitatively related to metal emissions from Italy, Switzerland, Germany, France, Belgium, and Austria at that time, making it possible to reconstruct past changes in metal emission in these countries during the last centuries.

Air Pollutants↗
PubMed2005

North Pacific seasonality and the glaciation of North America 2.7 million years ago.

In the context of gradual Cenozoic cooling, the timing of the onset of significant Northern Hemisphere glaciation 2.7 million years ago is consistent with Milankovitch's orbital theory, which posited that ice sheets grow when polar summertime insolation and temperature are low. However, the role of moisture supply in the initiation of large Northern Hemisphere ice sheets has remained unclear. The subarctic Pacific Ocean represents a significant source of water vapour to boreal North America, but it has been largely overlooked in efforts to explain Northern Hemisphere glaciation. Here we present alkenone unsaturation ratios and diatom oxygen isotope ratios from a sediment core in the western subarctic Pacific Ocean, indicating that 2.7 million years ago late-summer sea surface temperatures in this ocean region rose in response to an increase in stratification. At the same time, winter sea surface temperatures cooled, winter floating ice became more abundant and global climate descended into glacial conditions. We suggest that the observed summer warming extended into the autumn, providing water vapour to northern North America, where it precipitated and accumulated as snow, and thus allowed the initiation of Northern Hemisphere glaciation.

Arctic Regions↗
PubMed2001

Simultaneous ion-exclusion chromatography and cation-exchange chromatography of anions and cations in environmental water samples on a weakly acidic cation-exchange resin by elution with pyridine-2,6-dicarboxylic acid.

A non-suppressed conductivity detection ion chromatographic method using a weakly acidic cation-exchange column (Tosoh TSKgel OApak-A) was developed for the simultaneous separation and determination of common inorganic anions (Cl-, NO3- and SO4(2-)) and cations (Na+, NH4+, K+, Mg2+ and Ca2+). A satisfactory separation of these anions and cations on the weakly acidic cation-exchange column was achieved in 25 min by elution with a mixture of 1.6 mmol L-1 pyridine-2,6-dicarboxylic acid and 8.0 mmol L-1 18-crown-6 at flow rate of 1.0 mL min-1. On this weakly acidic cation-exchange resin, anions were retained by an ion-exclusion mechanism and cations by a cation-exchange mechanism. The linear range of the peak area calibration curves for all analytes were up to two orders of magnitude. The detection limits calculated at S/N = 3 ranged from 0.25 to 1.9 mumol L-1 for anions and cations. The ion-exclusion chromatography-cation-exchange chromatography method developed in this work was successfully applied to the simultaneous determination of major inorganic anions and cations in rainwater, tap water and snow water samples.

Chromatography, Ion Exchange↗
PubMed2004

[Ozone decline and UV increase].

The following results have been obtained from long-term observations on the ozone layer and UV at the Meteorological Observatory Hohenpeigenberg:The seasonally varying decline of the ozone layer determines the maximum exposure to UV. Since ozone decline shows the highest rates in the spring months the UV exposure has most strongly increased in this time of the year. This is especially important because in spring the human skin is not adapted to UV exposure. Weather changes from day to day can induce rapid ozone reductions in spring about -30% which in turn is followed by an increase in UV of about 40%. Clouds, especially the transparent cirrus clouds (high clouds consisting of ice particles) have increased in frequency during spring and fall while a decrease is observed in summer. This change in cloudiness reduces the daily UV dose in spring and fall while it is enhanced in summer. With increasing height above sea level UV rises by roughly 10% per 1000 m (rule of thumb). Snow reflects the UV-radiation by up to 80% enhancing the UV-doses at relevant conditions. Strong volcano eruptions destroy ozone in the stratosphere additionally during 1-2 years after the eruption. Therafter the ozone layer recovers. In April 1993, after the eruption of Mt. Pinatubo (1991), the UV burden was still 40% higher than average. Miniholes and streamers can appear unexpected on a short-time scale and cross over Central Europe within 1-2 days, thus enhancing UV irradiation. The human skin reacts to UV exposure depending on the type of skin. The campaign "Sonne(n) mit Verstand" of the Bavarian Ministries for Environment, for Health and for Education informs about the danger of UV radiation (see www.sonne-mit-ver-stand.de). The German Weather Service informs the public on present developments of the ozone layer and relevant topics byits ozone bulletin, which is also available via internet under (www.dwd.de/deFundE/Observator/MOHp/hp2/ozon/bulletin.htm).

Climate↗
PubMed2005

Fine-scale processes regulate the response of extreme events to global climate change.

We find that extreme temperature and precipitation events are likely to respond substantially to anthropogenically enhanced greenhouse forcing and that fine-scale climate system modifiers are likely to play a critical role in the net response. At present, such events impact a wide variety of natural and human systems, and future changes in their frequency and/or magnitude could have dramatic ecological, economic, and sociological consequences. Our results indicate that fine-scale snow albedo effects influence the response of both hot and cold events and that peak increases in extreme hot events are amplified by surface moisture feedbacks. Likewise, we find that extreme precipitation is enhanced on the lee side of rain shadows and over coastal areas dominated by convective precipitation. We project substantial, spatially heterogeneous increases in both hot and wet events over the contiguous United States by the end of the next century, suggesting that consideration of fine-scale processes is critical for accurate assessment of local- and regional-scale vulnerability to climate change.

Climate↗
PubMed2000

Climate change is affecting altitudinal migrants and hibernating species.

Calendar date of the beginning of the growing season at high altitude in the Colorado Rocky Mountains is variable but has not changed significantly over the past 25 years. This result differs from growing evidence from low altitudes that climate change is resulting in a longer growing season, earlier migrations, and earlier reproduction in a variety of taxa. At our study site, the beginning of the growing season is controlled by melting of the previous winter's snowpack. Despite a trend for warmer spring temperatures the average date of snowmelt has not changed, perhaps because of the trend for increased winter precipitation. This disjunction between phenology at low and high altitudes may create problems for species, such as many birds, that migrate over altitudinal gradients. We present data indicating that this already may be true for American robins, which are arriving 14 days earlier than they did in 1981; the interval between arrival date and the first date of bare ground has grown by 18 days. We also report evidence for an effect of climate change on hibernation behavior; yellow-bellied marmots are emerging 38 days earlier than 23 years ago, apparently in response to warmer spring air temperatures. Migrants and hibernators may experience problems as a consequence of these changes in phenology, which may be exacerbated if climate models are correct in their predictions of increased winter snowfall in our study area. The trends we report for earlier formation of permanent snowpack and for a longer period of snow cover also have implications for hibernating species.

Altitude↗
PubMed2004

A systems perspective of slip and fall accidents on icy and snowy surfaces.

Current research on slips and falls has mainly focused on floors and/or contaminated floors. Although icy and snowy surfaces near melting temperature are more slippery, more important still, slip and falls on icy and snowy surfaces involve not only outdoor workers, but also pedestrians and the general public; and occur in cold regions and in the winter season in many parts of the world. However, in comparison with the size of the problem, research work done so far in this area has been limited. The objective of this paper is to present a systems perspective of slip and fall accidents, with special focus on its occurrence on icy and snowy surfaces. In order to explore the aetiology of slip and fall accidents further, and to provide the basis for prevention, the authors put forward a systems model towards the slips and falls on icy and snowy surfaces based on a review of literature and current knowledge. Various contributing factors are systematically discussed to highlight the multi-factorial nature of the problem, providing the possibility of a multi-faceted approach to reach systematic prevention. Unresolved issues related to slips and falls on ice and snow are also identified, which necessitate further research.

Accidental Falls↗
PubMed1994

Analysis of the biomechanical characteristics of different swinging techniques in alpine skiing.

As a consequence of the increase in popularity of skiing as a leisure sport, ski teaching has become an important pedagogic and economic issue. Unfortunately, most ski teaching curricula lack a thorough evaluation of the most important swinging techniques. Therefore, this study analyses the biomechanical characteristics of swinging techniques in alpine skiing. The data were collected using biodynamic, kinematic and electromyographic methods, employing 21 test skiers, all of whom were state-certified Austrian ski instructors. For all techniques, the individual turns were divided into a steering phase and an initiation phase. In the main, the fundamental differences between the single techniques became apparent in the initiation phase. There it seemed useful to distinguish between turns with 'up-unweighting' and turns with 'down-unweighting'. It was found that turns with up-unweighting were initiated either from the downhill ski only or from both skis. Turns with down-unweighting were used primarily on mogul pistes and in deep powder snow. Finally, some conclusions for training methodology are given.

Acceleration↗
PubMed1998

Atrazine, alachlor, and total inorganic nitrogen concentrations of winter wind-eroded sediment samples.

The objective of this study was to determine if atrazine (2-chloro-4-ethylamino-6-isopropyl-1,3,5-triazine), alachlor [2-chloro-N-(2,6-diethylphenyl-N-(methoxymethyl)acetamide], or inorganic nitrogen was present on wind-eroded sediments collected from road ditch areas in mid to late winter. Sediment samples that had been deposited in ditches on top of snow were collected during the winters of 1994, 1995, and 1996 at randomly selected sites in eastern South Dakota and western Minnesota. Atrazine, atrazine metabolites [deethylatrazine (DEA)(6-chloro-N-1-methylethyl-1,3,5-triazine-2,4-diamine], and deisopropylatrazine (DIA) (6-chloro-N-ethyl-1,3,5-triazine-2,4-diamine), and alachlor were determined by gas chromatography. Total inorganic N (NO(3-) + NH4+) concentration was determined with a nitrogen analyzer. In all years, atrazine was detected in at least 72% of the samples, with a mean concentration of 8.9 ug kg-1 and, while DEA was detected in at least 18% of the samples. Alachlor was detected in at least 27% of the soil samples for all three years with mean sediment concentration of > 5 ug kg-1. Inorganic N concentration of all samples averaged 33 mg kg-1. These data suggest that deposition of wind-eroded sediment contributes to nonpoint source contamination of nontarget areas by agrichemicals.

Acetamides↗
PubMed2006

UV hazard on Italian Apennines under different shading and ground cover conditions during peak tourist seasons of the year.

In solar UV irradiance monitoring and forecasting services UV information is generally expressed in terms of its effect on erythema and referred to horizontal surface. In this work we define the UV radiative regime, in terms of biologically effective UV irradiance (UVBE) for skin and eye, under full sun and shaded conditions, over a mountainous tourist area of central Italy by means of two all-day measurements (summer and early spring) with different ground albedo (grass and snow cover respectively). UV irradiance was monitored on tilted surfaces (the most frequent for people standing and walking). Results show the significant contribution of ground albedo and sun position in determining the incident UVBE irradiance. On early spring days the UVBE irradiance measured on horizontal surface was much lower than on tilted ones; the opposite condition was observed in summer. The highest UVBE irradiance values, in particular conditions of sun elevation and ground cover, were reached in periods different from the summer both in full sun and shaded condition.

Erythema↗
PubMed1987

Monoclonal antibodies identify a group of nuclear pore complex glycoproteins.

Using monoclonal antibodies we identified a group of eight polypeptides of rat liver nuclear envelopes that have common epitopes. Most or all of these proteins are structurally distinct, as shown by tryptic peptide mapping and analysis with polyclonal antibodies. While these polypeptides are relatively tightly bound to nuclear membranes, only one is an integral membrane protein. The eight antigens cofractionate with the nuclear pore complex under various conditions of ionic strength and detergent. It can be seen by immunofluorescence microscopy that the monoclonal antibodies reacting with these antigens stain the nuclear surface of interphase cells in a finely punctate pattern. When the nuclear envelope is disassembled and subsequently reformed during mitosis, the proteins are reversibly dispersed throughout the cytoplasm in the form of minute foci. By EM immunogold localization on isolated nuclear envelopes, the monoclonal antibodies label exclusively the nuclear pore complex, at both its nucleoplasmic and cytoplasmic margins. Considered together, our biochemical and localization data indicate that the eight nuclear envelope polypeptides are pore complex components. As shown in the accompanying paper (Holt, G. D., C. M. Snow, A. Senior, R. S. Haltiwanger, L. Gerace, and G. W. Hart, J. Cell Biol., 104:1157-1164) these eight polypeptides contain a novel form of glycosylation, O-linked N-acetylglucosamine. The relative abundance and disposition of these O-linked glycoproteins in the pore complex are consistent with their having a role in nucleocytoplasmic transport.

Animals↗
PubMed1987

Nuclear pore complex glycoproteins contain cytoplasmically disposed O-linked N-acetylglucosamine.

A novel form of protein-saccharide linkage consisting of single N-acetylglucosamine (GlcNAc) residues attached in O-linkages directly to the polypeptide backbone has been described (Holt, G. D., and G. W. Hart, 1986, J. Biol. Chem., 261:8049-8057). This modification was found on proteins distributed throughout the cell, although proteins bearing O-linked GlcNAc moieties were particularly abundant in the cytosolic and nuclear envelope fractions of rat liver. In the accompanying article (Snow, C. M., A. Senior, and L. Gerace, 1987, J. Cell. Biol., 104: 1143-1156), the authors describe monoclonal antibodies directed against eight proteins localized to the nuclear pore complex. These proteins occur on the cytoplasmic and nucleoplasmic (but not lumenal) sides of nuclear membranes. In this report, we demonstrate that all members of this group of pore complex proteins bear multiple O-linked GlcNAc residues. Further, we show that the O-linked GlcNAc moieties are linked via serine (and possibly threonine) side chains to these proteins. Perturbing the O-linked GlcNAc residues either by covalently attaching galactose to them or by releasing them with beta-N-acetylglucosaminidase strongly diminishes the immunoreactivity of the proteins with all of the monoclonal antibodies. However, the O-linked GlcNAc moieties are only part of the epitopes recognized, since O-GlcNAc-containing limit pronase fragments of nuclear pore complex proteins cannot be immunoprecipitated by these antibodies. These findings, taken together with those in the accompanying article, are a direct demonstration that proteins of the cytoplasm and nucleoplasm bear O-linked GlcNAc residues.

Acetylglucosamine↗
PubMed1999

Effects of temperature and snowfall on mortality in Pennsylvania.

The relation between exposure to severe cold weather and mortality is examined in a retrospective study of deaths occurring during the month of January from 1991 to 1996 in Pennsylvania. Using division-days as units of observation (n = 1,560) aggregated from death certificates and geographic divisions, the authors estimated mortality rates for total deaths and deaths due to ischemic heart disease, cerebrovascular diseases, and respiratory diseases by analyses based on generalized estimating equations. Total mortality increased on days of "extreme" climatic conditions, that is, when snowfall was greater than 3 cm and when temperatures were below -7 degrees C (rate ratio (RR) = 1.27, 95 percent confidence interval (CI) 1.12-1.44). On days of extreme conditions, mortality due to ischemic heart diseases tripled among males aged 35-49 years (RR = 3.54, 95 percent CI 2.35-5.35), increased for men aged 50-64 years (RR = 1.77, 95 percent CI 1.32-2.38), and rose for males aged 65 years and older (RR = 1.58, 95 percent CI 1.37-1.82), when compared with milder conditions. Among females, mortality for those aged 65 years and older increased for respiratory causes (RR = 1.68, 95 percent CI 1.28-2.21) and cerebrovascular causes (RR = 1.47, 95 percent CI 1.13-1.91). Cold and snow exposure may be hazardous among men as young as 35 years.

Aged↗
PubMed1996

Novel purification and detailed characterization of perlecan isolated from the Engelbreth-Holm-Swarm tumor for use in an animal model of fibrillar A beta amyloid persistence in brain.

Co-infusion of the specific heparan sulfate proteoglycan (HSPG), perlecan, and beta-amyloid protein (A beta) into rodent hippocampus leads to a consistent animal model to study the effects of fibrillar A beta amyloid in brain [Snow, A.D. et al. (1994) Neuron 12, 219-234]. In the present study, we describe our rapid novel method of perlecan isolation. The isolation method does not require cesium chloride centrifugation and exploits a newly discovered aggregating property of a approximately 220 kDa PG observed during gel filtration chromatography, which allowed it to be affectively separated from non-aggregating perlecan. Fifty or 100 g of EHS tumor were routinely extracted using 4 M guanidine-HCl, followed by anion-exchange and gel filtration chromatography. SDS-PAGE (before and after digestion with heparitinase/heparinase or nitrous acid) followed by staining with silver demonstrated no other contaminating proteins in the perlecan preparations. Western blots using a specific perlecan core protein antibody (HK-102) following heparitinase digestion showed a characteristic doublet at 400 and 360 kDa indicative of intact perlecan core protein. Absence of contamination by other basement membrane components produced by the EHS tumor was confirmed by absence of immunoreactive bands on Western blots using antibodies against laminin, fibronectin, or type IV collagen. One week continuous co-infusion of perlecan obtained from this methodology, with A beta (1-40) into rodent hippocampus, led to deposition of fibrillar A beta amyloid in 100% (10 of 10) of animals. The detailed protocol for isolation and characterization of perlecan from EHS tumor ensures perlecan of the highest quality, and maximizes the potential effects of A beta amyloid deposition/persistence in brain using the animal model. High quality perlecan obtained from this novel isolation method will also allow future studies utilizing in vitro assays to determine the potential interactions of this specific HSPG with other macromolecules.

Alzheimer Disease↗
PubMed1998

Snowblower injuries to the hand.

A retrospective review of 22 patients who sustained snowblower injuries to the hand was performed. There were 17 men and 5 women, ranging in age from 20 to 68 years (average age, 39.7 years). Fifty percent were manual laborers, 25% were unemployed, 15% were office workers, and 10% were not categorized. The dominant hand was involved in 86% of patients. In all patients, injuries occurred during an attempt to unclog manually the snowblower of wet snow. Patients were evaluated initially in the emergency room, where their wounds were irrigated and debrided, subungual hematomas drained, and nail bed lacerations repaired. Patients with more extensive injuries were taken to the operating room for definitive treatment including open or closed reduction of fractures, fingertip replacement as composite grafts or skin grafts, revision amputations, tenorrhaphies, and digital nerve repairs. All injuries occurred distal to the metacarpophalangeal joints. Only 1 patient sustained an injury to the proximal phalanx. Ten patients injured only 1 finger, 6 patients injured 2 fingers, and 6 patients injured 3 fingers. The middle and ring fingers were most commonly injured (39.6% and 33.3% respectively), followed by the index and little fingers (16.7% and 8.3% respectively), and the thumb (2.1%). Phalangeal fractures were the most common type of injury, occurring in 29.2% of patients, and usually involved the distal phalanx. This was followed in frequency by nail bed injuries (22.9%), amputations (22.9%), tendon lacerations (14.6%), soft-tissue avulsions (6.3%), and digital nerve injuries (4.2%). Snowblower injuries can involve bone, soft tissue, nail bed structures, nerves, and tendons, and may even result in amputation of one or several fingers. These injuries are localized to the distal portions of the fingers. The middle and ring fingers are most commonly involved, with relative sparing of the thumb. Fractures are the most frequent injury, followed by nail bed injuries and amputations. Snowblower injuries are often managed as open fractures with intravenous antibiotics; irrigation and debridement; and repair of bone, soft tissue, and nail bed structures.

Adult↗
PubMed1989

Chernobyl fallout on Alpine glaciers.

Measurements of the gross beta activity of snow samples from four Alpine glaciers contaminated by radioactive fallout from the Chernobyl nuclear accident and a gamma-spectrum analysis of selected samples are reported. The results are discussed with respect to possible risks to the population from using meltwater from these glaciers as drinking water.

Accidents↗
PubMed1994

Femur fractures in Alpine skiing: classification and mechanisms of injury in 85 cases.

A retrospective review of 85 femur fractures sustained while alpine skiing in the north Lake Tahoe area was performed to determine incidence, severity, and mechanisms of injury. The incidence of femur fractures averaged 0.8 per 100,000 days of skiing and accounted for 0.4% of reported accidents in this series. Skiers sustaining femur fractures had a mean age of 30.2 years, significantly older than the skier mean age overall. Comminuted femoral shaft and trochanteric fractures that were the result of high-energy impact most often occurred in advanced skiers in firm or icy conditions. Firm ski conditions provided the most striking correlation to this type of fracture in the older age groups. In skeletally immature individuals (< 18 years of age), the femur fractures were mainly of the low-energy impact and minimally comminuted variety and were produced by an indirect, torsional, or bending mechanism. This injury typically occurred while skiing fast and resulted from catching the tip of a ski in wet or heavy snow. The majority of fractures (55%) occurred in the young adult population (18-45 years of age). Being predominantly advanced skiers, most of their fractures were the result of a high-energy, direct-impact fall or collision that led to severely comminuted femoral shaft and trochanteric fractures. Nineteen percent of those injured were > 45 years of age. More than two thirds of these individuals sustained fractures about the hip, typically a simple fracture in low-impact falls on hard or icy surfaces.

Adolescent↗
PubMed2003

Snowmobile injuries in North America.

The snowmobile was developed to move people and supplies, and for emergencies in regions where heavy snow prohibited the use of conventional vehicles. Today, snowmobiling has become a popular winter sport enjoyed by more than 2 million people of all ages in North America. However, the modern snowmobile can weigh in excess of 600 pounds and travel at speeds exceeding 90 miles per hour. Each year snowmobile accidents produce approximately 200 deaths and 14,000 injuries. Excess speed, alcohol, driver inexperience, and poor judgment are the leading causes of accidents. Injuries incurred in children and adults often are extremity fractures, but can involve any organ system. Similar to motor vehicle accidents, multisystem trauma occurs frequently with head injury the leading cause of death. Reduction in injury and death rates is urgently needed and can be accomplished through education and legislation.

Adolescent↗