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At least 811 records · Page 45Linked to original sources
PubMed2006

Stable oxygen isotopes (delta18(O)) in Austrocedrus chilensis tree rings reflect climate variability in northwestern Patagonia, Argentina.

The stable oxygen isotope (delta (18)O) composition of Austrocedrus chilensis (D. Don) Endl. (Cupressaceae) tree rings potentially provide retrospective views of changes in environment and climate in the semi-arid lands of Patagonia. We report the development of the first annually resolved delta (18)O tree-ring chronology obtained from natural forests of the foothills of the northwestern Patagonian Andes. The isotope record spans between 1890 and 1994 AD. We explore the probable links between this record and the climate of the region. Air temperatures during summer conditions are significantly, but not strongly, inversely correlated with annual delta (18)O values from Austrocedrus tree rings. The strongest correlations are between the southern oscillation index (SOI) and the tree rings. The existence of millennial-age Austrocedrus trees in northern Patagonia provides interesting possibilities for examining these climate-related isotopic signals over most of the last 1,000 years.

Argentina↗
PubMed2001

The influence of climatic variability on the quality of wine.

In this paper, the quality of the wine from the Dão (Viseu) region of Portugal is examined and relationships between wine quality and climatic variability are obtained using spectral and correlation analysis to determine the structure of the temporal variations. The spectra of the series of quality of wine values show statistically significant oscillations coherent with those found in the series of teleconnection indices. The series cover a period of 33 years. A significant correlation was obtained between wine quality and minimum air temperature in May, December and total precipitation in April. The teleconnection circulation indices are used to provide some physical insight into the most significant oscillating components of the climatic and the wine quality series. We found significant and positive correlations between the quality of the wine and the Southern Oscillation Index (SOI) of August and negative with the SOI of January and with the North Atlantic Oscillation of April. Wine quality and climatic series can be predicted using statistical models depending on significant oscillations.

Analysis of Variance↗
PubMed2005

Climatic factors and lower respiratory tract infection due to respiratory syncytial virus in hospitalised infants in northern Spain.

OBJECTIVE: To analyse the influence of climatic factors on the number of hospitalised infants with respiratory syncytial virus (RSV) per week. METHODS: A retrospective observational case-control study was designed enrolling infants under 2 years of age, admitted to hospital between October 1995 and June 2000 with lower respiratory tract infection due to RSV. Climatic and seasonal data were included. The week variable was used as the study unit: weeks with more than one admission for the case group and weeks without admissions for the control group. The total number of weeks excluding summer months, from June to September, was 174. RESULTS: A total of 167 infants were admitted to hospital with lower respiratory tract infection due to RSV with a peak in January and February. There was 82 weeks with one or more admissions (case group) and 92 without admissions (control group). The case group demonstrated lower levels of humidity (absolute: 5.6 +/- 1.5 vs. 6.5 +/- 1.5; p < 0.001) and lower temperature (ground level: 0.4 +/- 3.2 vs. 2.2 +/- 3.5; p < 0.001). When climatic factors were analysed in a logistic regression model, absolute humidity (p < 0.001) was an independent variable associated with a higher risk of infection. CONCLUSIONS: Low absolute humidity was independently associated with hospital admission of infants with lower respiratory tract infection due to RSV.

Case-Control Studies↗
PubMed2006

Geostatistical analysis of data on air temperature and plant phenology from Baden-Württemberg (Germany) as a basis for regional scaled models of climate change.

The rise of the air temperature is assured to be part of the global climatic change, but there is still a lack of knowledge about its effects at a regional scale. The article tackles the correlation of air temperature with the phenology of selected plants by the example of Baden-Württemberg to provide a spatial valid data base for regional climate change models. To this end, the data on air temperature and plant phenology, gathered from measurement sites without congruent coverage, were correlated after performing geostatistical analysis and estimation. In addition, geostatistics are used to analyze and cartographically depict the spatial structure of the phenology of plants in spring and in summer. The statistical analysis reveals a significant relationship between the rising air temperature and the earlier beginning of phenological phases like blooming or fruit maturation: From 1991 to 1999 spring time, as indicated by plant phenology, has begun up to 15 days earlier than from 1961 to 1990. As shown by geostatistics, this holds true for the whole territory of Baden-Württemberg. The effects of the rise of air temperature should be investigated not only by monitoring biological individuals, as for example plants, but on an ecosystem level as well. In Germany, the environmental monitoring should be supplemented by the study of the effects of the climatic change in ecosystems. Because air temperature and humidity have a great influence on the temporal and spatial distribution of pathogen carriers (vectors) and pathogens, mapping of the environmental determinants of vector and pathogen distribution in space and time should be performed in order to identify hot spots for risk assessment and further detailed epidemiological studies.

Air↗
PubMed2006

Climatic selection on genes and traits after a 100 year-old invasion: a critical look at the temperate-tropical clines in Drosophila melanogaster from eastern Australia.

Drosophila melanogaster invaded Australia around 100 years ago, most likely through a northern invasion. The wide range of climatic conditions in eastern Australia across which D. melanogaster is now found provides an opportunity for researchers to identify traits and genes that are associated with climatic adaptation. Allozyme studies indicate clinal patterns for at least four loci including a strong linear cline in Adh and a non-linear cline in alpha-Gpdh. Inversion clines were initially established from cytological studies but have now been validated with larger sample sizes using molecular markers for breakpoints. Recent collections indicate that some genetic markers (Adh and In(3R)Payne) have changed over the last 20 years reflecting continuing evolution. Heritable clines have been established for quantitative traits including wing length/area, thorax length and cold and heat resistance. A cline in egg size independent of body size and a weak cline in competitive ability have also been established. Postulated clinal patterns for resistance to desiccation and starvation have not been supported by extensive sampling. Experiments under laboratory and semi-natural conditions have suggested selective factors generating clinal patterns, particularly for reproductive patterns over winter. Attempts are being made to link clinal variation in traits to specific genes using QTL analysis and the candidate locus approach, and to identify the genetic architecture of trait variation along the cline. This is proving difficult because of inversion polymorphisms that generate disequilibrium among genes. Substantial gaps still remain in linking clines to field selection and understanding the genetic and physiological basis of the adaptive shifts. However D. melanogaster populations in eastern Australia remain an excellent resource for understanding past and future evolutionary responses to climate change.

Acclimatization↗
PubMed1984

Pyomyositis. Increasing recognition in temperate climates.

Pyomyositis is common in the tropics yet is rarely reported in temperate climates. A woman in whom pyomyositis developed in a temperate climate is presented. Computed tomography was the key in the diagnosis of the disease involving the muscles of the left lateral chest wall. The patient's condition responded to intravenous antibiotics and open abscess drainage. The 31 cases reported in the United States are reviewed. Unfamiliarity still poses a barrier to early diagnosis, although pyomyositis is being more frequently described in temperate climates.

Adult↗
PubMed1987

The case for a wet, warm climate on early Mars.

Theoretical arguments are presented in support of the idea that Mars possessed a dense CO2 atmosphere and a wet, warm climate early in its history. Calculations with a one-dimensional radiative-convective climate model indicate that CO2 pressures between 1 and 5 bars would have been required to keep the surface temperature above the freezing point of water early in the planet's history. The higher value corresponds to globally and orbitally averaged conditions and a 30% reduction in solar luminosity; the lower value corresponds to conditions at the equator during perihelion at times of high orbital eccentricity and the same reduced solar luminosity. The plausibility of such a CO2 greenhouse is tested by formulating a simple model of the CO2 geochemical cycle on early Mars. By appropriately scaling the rate of silicate weathering on present Earth, we estimate a weathering time constant of the order of several times 10(7) years for early Mars. Thus, a dense atmosphere could have persisted for a geologically significant time period (approximately 10(9) years) only if atmospheric CO2 was being continuously resupplied. The most likely mechanism by which this might have been accomplished is the thermal decomposition of carbonate rocks induced directly and indirectly (through burial) by intense, global-scale volcanism. For plausible values of the early heat flux, the recycling time constant is also of the order of several times 10(7) years. The amount of CO2 dissolved in standing bodies of water was probably small; thus, the total surficial CO2 inventory required to maintain these conditions was approximately 2 to 10 bars. The amount of CO2 in Mars' atmosphere would eventually have dwindled, and the climate cooled, as the planet's internal heat engine ran down. A test for this theory will be provided by spectroscopic searches for carbonates in Mars' crust.

Atmosphere↗
PubMed1984

Climate, socioeconomic status and Hodgkin's disease mortality in the United States.

This study examines the relative effects of climate and socioeconomic status (SES) on standard mortality ratios (SMR) from both young adult and older adult Hodgkin's disease (HD) in the United States. Climate variables explain a greater percentage of the variation in the SMR for HD than do SES variables. After adjusting for SES, indicators of climate exhibit a strong correlation with the young adult SMR, but not with the older adult SMR. These findings suggest that environmental factors play an important role in the etiology of young adult HD and support the hypothesis that young adult HD is a different disease from the older adult form.

Adult↗
PubMed1996

Instability of (methyl)ergometrine in tropical climates: an overview.

Parenteral ergometrine is widely used for the prevention and treatment of excessive uterine bleeding following birth. Unfortunately, in tropical climates it is often found to contain very little active ingredient: only 32 of 100 field samples from Bangladesh, Gambia, Malawi, Yemen and Zimbabwe contained 90-110% of the amount of active ingredient stated on the label, and 34 contained less than 60%. In this paper the results of nine studies, of which eight were initiated and coordinated by WHO, are reviewed to formulate answers to the following questions: (1) what is the extent of the problem of low potency of ergometrine in tropical climates; (2) is the problem due to instability or low initial quality, or both; (3) which practical measures can assure the quality of injectable ergometrine; and (4) are there any alternative drugs which are more stable? Injectable ergometrine is very unstable under tropical conditions and particularly if stored unrefrigerated and exposed to light, when it may loose up to 20% of its potency per month. However, there are differences between brands. Practical measures to assure the quality of injectable ergometrine therefore include a careful supplier selection and refrigerated storage. Ergometrine injection should always be protected from light until given to the patient. Loss of active ingredient can easily be detected by regular visual checks of the colour of the solution. Any discoloration implies that the solution contains less than 90% of the stated amount of active ingredient, and should not be used. Methylergometrine is no more stable than ergometrine. Parenteral oxytocin is more stable than both ergometrine and methylergometrine injection. Oral and buccal dosage forms are less stable than injections. In view of the better stability in tropical climates, similar cost, fewer side effects and comparative efficacy, parenteral oxytocin, rather than parenteral ergometrine, is the drug of choice in the prevention and treatment of postpartum haemorrhage.

Administration, Oral↗
PubMed1996

The effects of variable biome distribution on global climate.

In projecting climatic adjustments to anthropogenically elevated atmospheric carbon dioxide, most global climate models fix biome distribution to current geographic conditions. Previous biome maps either remain unchanging or shift without taking into account climatic feedbacks such as radiation and temperature. We develop a model that examines the albedo-related effects of biome distribution on global temperature. The model was tested on historical biome changes since 1860 and the results fit both the observed temperature trend and order of magnitude change. The model is then used to generate an optimized future biome distribution that minimizes projected greenhouse effects on global temperature. Because of the complexity of this combinatorial search, an artificial intelligence method, the genetic algorithm, was employed. The method is to adjust biome areas subject to a constant global temperature and total surface area constraint. For regulating global temperature, oceans are found to dominate continental biomes. Algal beds are significant radiative levers as are other carbon intensive biomes including estuaries and tropical deciduous forests. To hold global temperature constant over the next 70 years this simulation requires that deserts decrease and forested areas increase. The effect of biome change on global temperature is revealed as a significant forecasting factor.

Algorithms↗
PubMed1995

Weather changes and pain: perceived influence of local climate on pain complaint in chronic pain patients.

Patients with chronic pain frequently report that changes in the weather influence their pain. This study investigated differences in the perceived influence of weather on pain among 558 chronic pain patients living in 4 cities (San Diego, California; Nashville, Tennessee; Worcester, Massachusetts; and Boston, Massachusetts) in the United States. Local climatologic data for each city were obtained from the National Climatic Data Center. All patients completed a weather questionnaire, and the information they provided was compared with demographic and weather variables. The majority of all patients believed that changes in the weather affected their pain. Pain patients who were younger and who had arthritis reported the most sensitivity to changes in weather. Weather sensitivity was unrelated to all other demographic variables and to geographic region. Cold and damp conditions were considered to influence pain the most. However, the perceived effect of weather on pain was not found to be related to regional climate. Thus, the belief that pain is worsened by living in a colder climate was not supported. An equilibrium theory of weather changes and pain is discussed. Further investigations are needed to identify the mechanisms involved in the effects of weather changes on pain.

Adolescent↗
PubMed1988

Climate and the distribution of intestinal Trichostrongylus spp. of sheep.

The relative prevalences of Trichostrongylus vitrinus, T. colubriformis and T. rugatus in sheep in south-west Western Australia were examined for evidence of associations with climatic conditions in different localities. The region has a mediterranean-type climate with hot, dry summers and cool, wet winters. The intestinal Trichostrongylus spp. populations in sheep sampled comprised 50% T. vitrinus, 38% T. colubriformis and 12% T. rugatus. The prevalence of T. vitrinus was negatively correlated with mean autumn, winter and spring temperatures of a locality. The prevalence of T. colubriformis was positively correlated with mean autumn, winter and spring temperatures. The prevalence of T. rugatus was not correlated with temperature of any season, but was negatively correlated with mean annual rainfall and length of growing season of a locality. There were suggestions of association of amount of rainfall of a locality and prevalence of T. rugatus was not correlated with temperature of any season, but was negatively correlated with mean annual rainfall and length of growing season of a locality. There were suggestions of association of amount of rainfall of a locality and prevalence of T. colubriformis and of differences in seasonal prevalence of T. vitrinus, but the significance of these was obscured by confounding of some climatic factors. The differences in prevalence of the three Trichostrongylus spp. at different locations was attributed to differences in preferred ambient conditions for development and survival of the free-living stages.

Animals↗
PubMed2006

When smoke gets in our eyes: the multiple impacts of atmospheric black carbon on climate, air quality and health.

With both climate change and air quality on political and social agendas from local to global scale, the links between these hitherto separate fields are becoming more apparent. Black carbon, largely from combustion processes, scatters and absorbs incoming solar radiation, contributes to poor air quality and induces respiratory and cardiovascular problems. Uncertainties in the amount, location, size and shape of atmospheric black carbon cause large uncertainty in both climate change estimates and toxicology studies alike. Increased research has led to new effects and areas of uncertainty being uncovered. Here we draw together recent results and explore the increasing opportunities for synergistic research that will lead to improved confidence in the impact of black carbon on climate change, air quality and human health. Topics of mutual interest include better information on spatial distribution, size, mixing state and measuring and monitoring.

Aerosols↗
PubMed2006

Integrated effects of air pollution and climate change on forests: a northern hemisphere perspective.

Many air pollutants and greenhouse gases have common sources, contribute to radiative balance, interact in the atmosphere, and affect ecosystems. The impacts on forest ecosystems have been traditionally treated separately for air pollution and climate change. However, the combined effects may significantly differ from a sum of separate effects. We review the links between air pollution and climate change and their interactive effects on northern hemisphere forests. A simultaneous addressing of the air pollution and climate change effects on forests may result in more effective research, management and monitoring as well as better integration of local, national and global environmental policies.

Air Pollution↗
PubMed2006

Impact of weather and climate on the incidence of acute coronary syndromes.

BACKGROUND: First investigations of the interactions between weather and the incidence of acute myocardial infarctions date back to 1938. The early observation of a higher incidence of myocardial infarctions in the cold season could be confirmed in very different geographical regions and cohorts. While the influence of seasonal variations on the incidence of myocardial infarctions has been extensively documented, the impact of individual meteorological parameters on the disease has so far not been investigated systematically. Hence the present study intended to assess the impact of the essential variables of weather and climate on the incidence of myocardial infarctions. METHODS: The daily incidence of myocardial infarctions was calculated from a national hospitalization survey. The hourly weather and climate data were provided by the database of the national weather forecast. The epidemiological and meteorological data were correlated by multivariate analysis based on a generalized linear model assuming a log-link-function and a Poisson distribution. RESULTS: High ambient pressure, high pressure gradients, and heavy wind activity were associated with an increase in the incidence of the totally 6560 hospitalizations for myocardial infarction irrespective of the geographical region. Snow- and rainfall had inconsistent effects. Temperature, Foehn, and lightning showed no statistically significant impact. CONCLUSIONS: Ambient pressure, pressure gradient, and wind activity had a statistical impact on the incidence of myocardial infarctions in Switzerland from 1990 to 1994. To establish a cause-and-effect relationship more data are needed on the interaction between the pathophysiological mechanisms of the acute coronary syndrome and weather and climate variables.

Climate↗
PubMed2006

Suicide rates and the association with climate: a population-based study.

BACKGROUND: Seasonality of suicide has been noted in several studies. A spring peak of suicide was observed, and associations between various climatic parameters and suicide have been suggested. This study sets out to verify seasonal patterns of suicide rates and to explore the association with climate in Taiwan. METHOD: The study used a nationwide mortality database in Taiwan from January 1997 to December 2003. An autoregressive integrated moving average model was applied to examine the presence of seasonality and the association of climate with suicidal death. RESULTS: Seasonality with a spring peak was evident in suicidal death regardless of gender or age. Ambient temperature was positively associated with suicide after adjustment for trend and seasonality. LIMITATIONS: Misclassification and underreporting of suicidal death in the registry system might confound the results. Ecological fallacies might exist. CONCLUSIONS: The seasonal effect on suicide is significant in Taiwan. Suicide rates may be influenced by ambient temperatures. The findings are of research interest for future studies regarding mechanisms of suicidal behavior, and also of practical interest for better timing of suicide interventions and effective preventive strategies.

Adolescent↗
PubMed2005

Effects of climate and land use changes on groundwater resources in coastal aquifers.

To estimate the freshwater loss in coastal aquifers due to salinisation, a numerical model based on the sharp interface assumption has been introduced. The developed methodology will be useful in areas where limited hydrological data are available. This model will elaborate on the changes in fresh groundwater loss with respect to climate change, land use pattern and hydrologic soil condition. The aridity index has been introduced to represent the variations in precipitation and temperature. The interesting finding is that the deforestation leads to increase groundwater recharge in arid areas, because deforestation leads to reduce evapotranspiration even though it favors runoff. The combined climate and land use scenarios show that when the aridity index is less than 60, the agricultural lands give higher groundwater recharge than other land use patterns for all hydrologic soil conditions. The calculated recharge was then used to estimate the freshwater-saltwater interface and percentage of freshwater loss due to salinity intrusion. We found that in arid areas, the fresh groundwater loss increases as the percentage of forest cover increases. The combined effects of deforestation and aridity index on fresh groundwater loss show that deforestation causes an increase in the recharge and existing fresh groundwater resource in areas having low precipitation and high temperature (arid climates).

Agriculture↗
PubMed2006

Temporal neural networks for downscaling climate variability and extremes.

This paper presents an application of temporal neural networks for downscaling global climate models (GCMs) output. Because of computational constraints, GCMs are usually run at coarse grid resolution (in the order of 100s of kilometres) and as a result they are inherently unable to present local sub-grid scale features and dynamics. Consequently, outputs from these models cannot be used directly in many climate change impact studies. This research explored the issues of 'downscaling' the outputs of GCMs using a temporal neural network (TNN) approach. The method is proposed for downscaling daily precipitation and temperature series for a region in northern Quebec, Canada. The downscaling models are developed and validated using large-scale predictor variables derived from the National Center for Environmental Prediction (NCEP) reanalysis data set. The performance of the temporal neural network downscaling model is also compared to a regression-based statistical downscaling model with emphasis on their ability in reproducing the observed climate variability and extremes. The downscaling results for the base period (1961-2000) suggest that the TNN is an efficient method for downscaling both daily precipitation as well as daily maximum and minimum temperature series. Furthermore, the different model test results indicate that the TNN model mostly outperforms the statistical models for the downscaling of daily precipitation extremes and variability.

Climate↗