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At least 1,027 records · Page 57Linked to original sources
PubMed2003

School climate and implementation of the Pathways study.

BACKGROUND: Pathways was a multisite school-based study to prevent obesity in American Indian school children by encouraging healthy eating and physical activity. METHODS: Over the 3-year study, a total of 290 in-depth interviews were conducted with school administrators, food service managers, classroom teachers, and physical education instructors in all 21 intervention schools to examine support and barriers for Pathways. Analysis included qualitative assessment of key themes using NUD*IST and quantitative modeling of the impact of a school climate score on implementation of intervention components. RESULTS: Overall, teachers, food service managers, and physical education instructors were supportive of the Pathways interventions. School administration and lack of family participation were perceived barriers at some schools. Attitudes toward the program ranged from neutral to positive during the first year, with about two-thirds giving positive ratings, with greater variation in successive years. Overall, the mean score was 3.5 on a 5-point scale (1=very negative, 5=very positive). School climate score was positively associated with classroom curriculum and student exposure indices, but not with family attendance, food service, or physical activity implementation indices. The latter two indices were associated with site. CONCLUSIONS: An assessment of school climate through interviews is useful in understanding successes and failures in a school-based health intervention and can predict implementation success for some programs.

Child↗
PubMed1998

Biological dosimetry to determine the UV radiation climate inside the MIR station and its role in vitamin D biosynthesis.

The vitamin D synthesis in the human skin, is absolutely dependent on UVB radiation. Natural UVB from sunlight is normally absent in the closed environment of a space station like MIR. Therefore it was necessary to investigate the UV radiation climate inside the station resulting from different lamps as well as from occasional solar irradiation behind a UV-transparent quartz window. Biofilms, biologically weighting and integrating UV dosimeters successfully applied on Earth (e.g. in Antarctica) and in space (D-2, Biopan I) were used to determine the biological effectiveness of the UV radiation climate at different locations in the space station. Biofilms were also used to determine the personal UV dose of an individual cosmonaut. These UV data were correlated with the concentration of vitamin D in the cosmonaut's blood and the dietary vitamin D intake. The results showed that the UV radiation climate inside the Mir station is not sufficient for an adequate supply of vitamin D, which should therefore be secured either by vitamin D supplemental and/or by the regular exposure to special UV lamps like those in sun-beds. The use of natural solar UV radiation through the quartz window for 'sunbathing' is dangerous and should be avoided even for short exposure periods.

25-Hydroxyvitamin D 2↗
PubMedDate not supplied

Use of local climatic data to determine if weather precludes the operation of an air medical system.

INTRODUCTION: Weather is one of many factors that affect safety in an air medical program. Syracuse, New York, has notoriously bad weather, and some have questioned whether an air medical service is practical given central New York's climate. This study was undertaken to determine the extent to which the area's climate could be expected to limit the availability of an air medical service. METHODS: CAMTS weather minimums for rotor-wing programs were compared with 1996-1997 hourly weather observations from the Northeastern Regional Climate Center (NRCC) and sunrise/sunset data from the United States Naval Observatory to determine how frequently weather conditions could be expected to preclude an air medical response in the greater Syracuse area. RESULTS: Exactly 17,544 hourly observations were made. CAMTS weather minimums would have precluded local flights for 606 (3.5%) of these hours and cross-country flights for 1111 (6.3%) hours. Cross-country flights were more likely to be precluded than local flights (P = .001), and both local and cross-country flights were more likely to be precluded at nighttime than in the daytime (P = .001). All flights were more likely to be precluded during winter months than during summer months (P = .000). CONCLUSION: The weather in central New York generally does not preclude the operation of an air medical services system.

Air Ambulances↗
PubMedDate not supplied

Relationships among student and graduate caring ability and professional school climate.

This study represents the second phase in a longitudinal study of the development of caring ability in registered nurses. A nationwide sample of female graduates of US baccalaureate nursing programs was resurveyed 3 years after the phase-one survey taken during nursing school. The purpose of the study was to continue an evaluation of several variables contributing to the development of professional caring ability. Previously validated instruments were used to measure caring ability (Caring Ability Inventory), maternal and paternal care (Parental Bonding Instrument), and the caring climate of the respective nursing schools (Charles F. Kettering Ltd. School Climate Profile). Although parental bonding scores remained unchanged from the initial survey, caring ability scores significantly increased after entry into practice (paired student's t test, P < .001). The strongest predictor of postgraduate caring ability was student caring ability scores (r = .58, P < .001). When student caring ability scores were excluded as a potential predictor during stepwise multiple regression analysis, school climate scores were the strongest predictor of postgraduate caring ability (r = .17, P < .05). This suggests that development of professional caring ability is related to caring school environments. Furthermore, caring ability as a student predicts further development of caring ability after entry into practice.

Adult↗
PubMedDate not supplied

Nurse practitioners: leadership behaviors and organizational climate.

The purpose of this article is to examine the relationships of individual nurse practitioners' perceptions of the leadership climate in their organizations and self-reported formal and informal leadership behaviors. The nine climate dimensions (Structure, Responsibility, Reward, Perceived Support of Risk Taking, Warmth, Support, Standard Setting, Conflict, and Identity) identified by Litwin and Stringer in 1968 were used to predict five leadership dimensions (Meeting Organizational Needs, Managing Resources, Leadership Competence, Task Accomplishment, and Communications). Demographic variables of age, educational level, and percent of time spent performing administrative functions were forced as a first step in each multiple regression analysis and used to explain a significant amount of variance in all but one analysis. All leadership dimensions were predicted by at least one organizational climate dimension: (1) Meeting Organizational Needs by Risk and Reward; (2) Managing Resources by Risk and Structure; (3) Leadership Competence by Risk and Standards; (4) Task Accomplishment by Structure, Risk, and Standards; and (5) Communication by Rewards.

Adult↗
PubMed2003

Atmospheric deposition of V, Cr, and Ni since the late glacial: effects of climatic cycles, human impacts, and comparison with crustal abundances.

Vanadium, Cr, and Ni accumulating in a Swiss peat bog since 12 370 14C yr B.P. have been measured using inductively coupled plasma-mass spectrometry (ICP-MS) after acid dissolution in a microwave autoclave. Strict quality control schemes were applied to guarantee the accuracy of the applied analytical methodology. The concentration gradients in the peat column and comparison with Pb indicate that V, Cr, and Ni are effectively immobile in the ombrotrophic section of the peat profile but that Ni is added to the minerotrophic peat layers by chemical weathering of the underlying sediments. The lowest metal concentrations were found during the Holocene climate optimum (5320-8230 14C yr B.P.) when "natural background" values averaged 0.55 +/- 0.13 microg g(-1) V, 0.76 +/- 0.17 microg g(-1) Cr, and 0.46 +/- 0.09 microg g(-1) Ni (n = 18); given the average bulk density (0.05 g/cm3) and accumulation rate (0.05 cm/ yr) of peat in this zone, the corresponding atmospheric fluxes are approximately 14, 19, and 12 microg m(-2) yr(-1) for V, Cr, and Ni, respectively. The highest concentrations of V, Cr, and Ni were found during the Younger Dryas cold climate event (centered at 10 590 14C yr B.P.) when background values were exceeded by about 40 times. Elevated concentrations and accumulation rates were also found at 8230 and 5320 14C yr B.P., which are consistent with the elevated dust fluxes recorded by Greenland ice cores. By far the greatest contribution of the three elements to the peat inventory is atmospheric soil dust, and the metal fluxes vary not only with climate change but also land-use history (especially the beginning of forest clearing for agriculture ca. 6 millennia ago). The V/Sc, Cr/Sc, and Ni/ Sc ratios were remarkably similar to their corresponding ratios in the earth's crust until the onset of the Industrial Revolution (240 14C yr B.P.), which largely validates the use of crustal concentrations for calculating enrichment factors (EF) for these elements. In modern samples, the EFs of V, Cr, and Ni reach maximum values between 2.4 and 4.1, relative to background; anthropogenic emissions are a more likely explanation of the elevated EFs than either plant uptake or chemical diagenesis. This study demonstrates the usefulness of peat bogs as archives of atmospheric metal deposition and underpins the potential of peat cores to help distinguish between lithogenic and anthropogenic metal sources.

Air Pollutants↗
PubMed2000

Spontaneous pneumothorax related with climatic characteristics in the Valencia area (Spain).

Spontaneous pneumothorax (SP) is a common respiratory condition that is easily recognized and treated, though the etiology remains largely unknown. Apart from individual factors, it has been suggested that changes in atmospheric pressure may trigger the onset of SP. Our aim was to examine the association between the onset of episodes of SP with atmospheric pressure changes in the general population of an area with a Mediterranean climate. A prospective survey was conducted to detect all episodes of SP in a region of Valencia (Spain) from January 1994 to January 1996. A total of 69 cases were identified; of these, 62 episodes of SP met the inclusion criteria for this survey. Climatic measurements during the two years studied were obtained from the Spanish National Meteorological Institute, including 6-hour readings of temperature, relative humidity, clear sunlight, atmospheric pressure, visibility, wind speed and rainfall. Associations were evaluated between the daily number of hospital admissions for SP and diurnal changes in atmospheric pressure involving rises and falls of as much as 7 and 10 mbar. In addition, the association of atmospheric pressure changes to time periods of 1 a.m., 7 a.m., 1 p.m. and 7 p.m. was assessed. Drops in atmospheric pressure below the fifth percentile and elevations above the ninety-fifth percentile were regarded as 'unusual'. There was no association between the development of SP and changes in atmospheric pressure, and no correlation was found with repeated exposure to unusual changes of atmospheric pressure. Further research is needed using similar methods to establish comparisons between countries with different climates.

Adolescent↗
PubMed1996

A new look at psychological climate and its relationship to job involvement, effort, and performance.

This study investigated the process by which employee perceptions of the organizational environment are related to job involvement, effort, and performance. The researchers developed an operational definition of psychological climate that was based on how employees perceive aspects of the organizational environment and interpret them in relation to their own well-being. Perceived psychological climate was then related to job involvement, effort, and performance in a path-analytic framework. Results showed that perceptions of a motivating and involving psychological climate were related to job involvement, which in turn was related to effort. Effort was also related to work performance. Results revealed that a modest but statistically significant effect of job involvement on performance became nonsignificant when effort was inserted into the model, indicating the mediating effect of effort on the relationship. The results cross-validated well across 2 samples of outside salespeople, indicating that relationships are generalizable across these different sales contexts.

Adult↗
PubMed2001

To transfer or not to transfer? Investigating the combined effects of trainee characteristics, team leader support, and team climate.

Eighty pilots participated in a study of variables influencing the transfer process. Posttraining performance was assessed in a flight simulation under 1 of 2 conditions. Those in the maximum performance condition were made aware of the skill to be assessed and the fact that their teammates were confederates, whereas those in the typical performance condition were not. The results indicated that (a) simulator ratings correlated with a measure of transfer to the cockpit for those in the typical condition only; (b) team leader support, manipulated in a pretask brief, moderated the disparity between maximum and typical performance; (c) team climate mediated the impact of support on performance in the typical condition; (d) those with a stronger predisposition toward the trained skill viewed their climate as more supportive; and (e) perceptions of team climate were better predictors of performance for those with a more external locus of control.

Adult↗
PubMed2000

Acclimation of ecosystem CO2 exchange in the Alaskan Arctic in response to decadal climate warming

Long-term sequestration of carbon in Alaskan Arctic tundra ecosystems was reversed by warming and drying of the climate in the early 1980s, resulting in substantial losses of terrestrial carbon. But recent measurements suggest that continued warming and drying has resulted in diminished CO2 efflux, and in some cases, summer CO2 sink activity. Here we compile summer CO2 flux data for two Arctic ecosystems from 1960 to the end of 1998. The results show that a return to summer sink activity has come during the warmest and driest period observed over the past four decades, and indicates a previously undemonstrated capacity for ecosystems to metabolically adjust to long-term (decadal or longer) changes in climate. The mechanisms involved are likely to include changes in nutrient cycling, physiological acclimation, and population and community reorganization. Nevertheless, despite the observed acclimation, the Arctic ecosystems studied are still annual net sources of CO2 to the atmosphere of at least 40 g C m(-2) yr(-1), due to winter release of CO2, implying that further climate change may still exacerbate CO2 emissions from Arctic ecosystems.

Journal Article↗
PubMed2000

Quantifying the uncertainty in forecasts of anthropogenic climate change

Forecasts of climate change are inevitably uncertain. It is therefore essential to quantify the risk of significant departures from the predicted response to a given emission scenario. Previous analyses of this risk have been based either on expert opinion, perturbation analysis of simplified climate models or the comparison of predictions from general circulation models. Recent observed changes that appear to be attributable to human influence provide a powerful constraint on the uncertainties in multi-decadal forecasts. Here we assess the range of warming rates over the coming 50 years that are consistent with the observed near-surface temperature record as well as with the overall patterns of response predicted by several general circulation models. We expect global mean temperatures in the decade 2036-46 to be 1-2.5 K warmer than in pre-industrial times under a 'business as usual' emission scenario. This range is relatively robust to errors in the models' climate sensitivity, rate of oceanic heat uptake or global response to sulphate aerosols as long as these errors are persistent over time. Substantial changes in the current balance of greenhouse warming and sulphate aerosol cooling would, however, increase the uncertainty. Unlike 50-year warming rates, the final equilibrium warming after the atmospheric composition stabilizes remains very uncertain, despite the evidence provided by the emerging signal.

Journal Article↗
PubMed2000

Microseismological evidence for a changing wave climate in the northeast Atlantic Ocean.

One possible consequence of a change in climate over the past several decades is an increase in wave heights, potentially threatening coastal areas as well as the marine industry. But the difficulties in observing wave heights exacerbates a general problem of climate-change detection: inhomogeneities in long-term observational records owing to changes in the instruments or techniques used, which may cause artificial trends. Ground movements with periods of 4-16 seconds, known as microseisms, are associated with ocean waves and coastal surf, and have been recorded continuously since the early days of seismology. Here we use such a 40-year record of wintertime microseisms from Hamburg, Germany, to reconstruct the wave climate in the northeast Atlantic Ocean. For the period 1954-77, we detect an average of seven days per month with strong microseismic activity, without a significant trend. This number increases significantly in the second half of the record, reaching approximately 14 days of strong microseisms per month. The implied increase in northeast Atlantic wave height over the past 20 years parallels increased surface air temperatures and storminess in this region, suggesting a common forcing.

Journal Article↗
PubMed2001

An abrupt climate event in a coupled ocean-atmosphere simulation without external forcing.

Temperature reconstructions from the North Atlantic region indicate frequent abrupt and severe climate fluctuations during the last glacial and Holocene periods. The driving forces for these events are unclear and coupled atmosphere-ocean models of global circulation have only simulated such events by inserting large amounts of fresh water into the northern North Atlantic Ocean. Here we report a drastic cooling event in a 15,000-yr simulation of global circulation with present-day climate conditions without the use of such external forcing. In our simulation, the annual average surface temperature near southern Greenland spontaneously fell 6-10 standard deviations below its mean value for a period of 30-40 yr. The event was triggered by a persistent northwesterly wind that transported large amounts of buoyant cold and fresh water into the northern North Atlantic Ocean. Oceanic convection shut down in response to this flow, concentrating the entire cooling of the northern North Atlantic by the colder atmosphere in the uppermost ocean layer. Given the similarity between our simulation and observed records of rapid cooling events, our results indicate that internal atmospheric variability alone could have generated the extreme climate disruptions in this region.

Journal Article↗
PubMed2001

Increased sedimentation rates and grain sizes 2-4 Myr ago due to the influence of climate change on erosion rates.

Around the globe, and in a variety of settings including active and inactive mountain belts, increases in sedimentation rates as well as in grain sizes of sediments were recorded at approximately 2-4 Myr ago, implying increased erosion rates. A change in climate represents the only process that is globally synchronous and can potentially account for the widespread increase in erosion and sedimentation, but no single process-like a lowering of sea levels or expanded glaciation-can explain increases in sedimentation in all environments, encompassing continental margins and interiors, and tropical as well as higher latitudes. We suggest that climate affected erosion mainly by the transition from a period of climate stability, in which landscapes had attained equilibrium configurations, to a time of frequent and abrupt changes in temperature, precipitation and vegetation, which prevented fluvial and glacial systems from establishing equilibrium states.

Journal Article↗
PubMed2002

Quantifying the risk of extreme seasonal precipitation events in a changing climate.

Increasing concentrations of atmospheric carbon dioxide will almost certainly lead to changes in global mean climate. But because--by definition--extreme events are rare, it is significantly more difficult to quantify the risk of extremes. Ensemble-based probabilistic predictions, as used in short- and medium-term forecasts of weather and climate, are more useful than deterministic forecasts using a 'best guess' scenario to address this sort of problem. Here we present a probabilistic analysis of 19 global climate model simulations with a generic binary decision model. We estimate that the probability of total boreal winter precipitation exceeding two standard deviations above normal will increase by a factor of five over parts of the UK over the next 100 years. We find similar increases in probability for the Asian monsoon region in boreal summer, with implications for flooding in Bangladesh. Further practical applications of our techniques would be helped by the use of larger ensembles (for a more complete sampling of model uncertainty) and a wider range of scenarios at a resolution adequate to analyse average-size river basins.

Journal Article↗
PubMed2002

Increasing risk of great floods in a changing climate.

Radiative effects of anthropogenic changes in atmospheric composition are expected to cause climate changes, in particular an intensification of the global water cycle with a consequent increase in flood risk. But the detection of anthropogenically forced changes in flooding is difficult because of the substantial natural variability; the dependence of streamflow trends on flow regime further complicates the issue. Here we investigate the changes in risk of great floods--that is, floods with discharges exceeding 100-year levels from basins larger than 200,000 km(2)--using both streamflow measurements and numerical simulations of the anthropogenic climate change associated with greenhouse gases and direct radiative effects of sulphate aerosols. We find that the frequency of great floods increased substantially during the twentieth century. The recent emergence of a statistically significant positive trend in risk of great floods is consistent with results from the climate model, and the model suggests that the trend will continue.

Journal Article↗
PubMed2002

Climate change in the North Pacific region over the past three centuries.

The relatively short length of most instrumental climate records restricts the study of climate variability, and it is therefore essential to extend the record into the past with the help of proxy data. Only since the late 1940s have atmospheric data been available that are sufficient in quality and spatial resolution to identify the dominant patterns of climate variability, such as the Pacific North America pattern and the Pacific Decadal Oscillation. Here we present a 301-year snow accumulation record from an ice core at a height of 5,340 m above sea level-from Mount Logan, in northwestern North America. This record shows features that are closely linked with the Pacific North America pattern for the period of instrumental data availability. Our record extends back in time to cover the period from the closing stages of the Little Ice Age to the warmest decade in the past millennium. We find a positive, accelerating trend in snow accumulation after the middle of the nineteenth century. This trend is paralleled by a warming over northwestern North America which has been associated with secular changes in both the Pacific North America pattern and the Pacific Decadal Oscillation.

Journal Article↗
PubMed2003

Homogeneous climate variability across East Antarctica over the past three glacial cycles.

Recent ice core studies have raised the disturbing possibility that glacial-interglacial climate changes may be non-uniform across Antarctica. These findings have been confined to records from the Ross Sea sector of the continent, but significant deviations in other areas would call into question the widely assumed validity of the climate record obtained from Vostok, East Antarctica, on large spatial scales. Here we present an isotopic profile from a core drilled at Dome Fuji, situated 1,500 km from Vostok in a different sector of East Antarctica. The two records show remarkable similarities over the past three glacial cycles (the extent of the Dome Fuji record) in both large-amplitude changes, such as terminations, interglacials and interstadials and more subtle glacial events, even when the origin of precipitation is accounted for. Our results indicate that Antarctic climate is essentially homogeneous at the scale of the East Antarctic Plateau, possibly as a consequence of the symmetry of the plateau and the adjacent ocean.

Journal Article↗