Large Geographical Variations Research Articles

Geographical variation in the incidence of acute myocardial infarction in eastern Finland — a Bayesian perspective

BACKGROUND: Large geographical variation in the incidence and mortality of cardiovascular disease (CHD) has been repeatedly reported in Finland with persistent difference between east and west. We undertook this study to estimate the geographical distribution of Acute Myocardial Infarction (AMI) incidence in the high‐risk province of North Karelia and in the province of Kuopio.METHODS: Data on men aged 25–64 years with first event of acute myocardial infarction (AMI) were obtained from the FINMONICA AMI register, which recorded detailed information of AMI events during the period 1983 to 1992. The geographical pattern of AMI incidence was studied in two five‐year periods 1983 to 1987 and 1988 to 1992 separately in 10 km × 10 km grid cells employing the Geographical Information System (GIS) and a Bayesian hierarchical approach.RESULTS: In both periods Bayesian modeling revealed a geographical pattern of AMI incidence and high risk (probability that incidence exceeds the observed mean incidence) in the remote rural areas.CONCLUSIONS: Detection of high‐risk areas in both provinces showed that underlying environmental and/or genetic risk factors of AMI are not evenly distributed within the province but enriched in certain geographical non‐administratively defined locations in eastern Finland.

Geographical Variations in Prosome Length and Body Weight of Neocalanus Copepods in the North Pacific

Geographical variations in prosome length and body weight of Neocalanus copepods (N. cristatus, N. plumchrus and N. flemingeri) were investigated on samples from North-South and East-West transects in the North Pacific during spring to early summer in 1998 and 1999. Southward and eastward increasing patterns were pronounced for water temperature, although no significant pattern was observed for chlorophyll a concentrations. All Neocalanus species showed large geographical variations in prosome length and body weight, being smaller in the southern and eastern waters. Comparing the relationship between prosome length and body weight, large deviations (lower body weight at a given prosome length) were evident for the eastern specimens of N. cristatus and N. plumchrus. In stepwise regression analysis, the geographical variations of prosome length and body weight revealed a significantly negative correlation with temperature variations. These results suggest that temperature is a more important environmental factor than chlorophyll a concentration in its effect on geographical variations in prosome length and body weight of Neocalanus copepods in the North Pacific.

The Fate of Clades in a World of Recurrent Climatic Change: Milankovitch Oscillations and Evolution

▪ Abstract Variations in Earth's orbit with periods of 10–100 thousand years (kyr) (Milankovitch oscillations) have led to recurrent and rapid climatic shifts throughout Earth's history. These cause changes in the geographical distributions of clades, which we term orbitally forced range dynamics (ORD). The magnitude of ORD varies geographically, e.g., with latitude. Climatic shifts cause extinction, splitting, and merging of gene pools and clades. They select among individuals and clades for traits enhancing the ability to survive in situ and to establish new populations. There is also nonadaptive sorting caused by the large geographical variation in ORD, as only gene pools that are in the right place when climate shifts survive. ORD lead to sorting at many levels of genealogic inclusiveness. Clades that have survived climatic shifts during at least one entire period of the longest significant Milankovitch oscillations (100 kyr), we name β-clades. The products of more recent cladogenesis are α-clades, which are always nested within a β-clade. We conclude that ORD may promote α-clade formation but curb rates of β-clade formation. In areas with little ORD, where gene pools persist without going extinct or merging, clade splits and divergence may accumulate leading to high rates of β-clade formation and β-anagenesis (evolutionary change persisting >100 kyr). High ORD should lead to low numbers of β-clades, β-clades with low levels of spatial genetic divergence, little geographical subdivision and large ranges, organisms with high vagility and low specialization, high proportions of β-clades formed by polyploidization, and little β-anagenesis. We predict global and interregional geographic patterns in these variables caused by differential ORD. Thus, ORD potentially explains a wide array of patterns, suggesting ORD as a fundamental factor in evolution. The vulnerability of biotas to many human activities should vary with the magnitude of ORD.

Tropospheric Aerosol Optical Thickness from the GOCART Model and Comparisons with Satellite and Sun Photometer Measurements

The Georgia Institute of Technology‐Goddard Global Ozone Chemistry Aerosol Radiation and Transport (GOCART) model is used to simulate the aerosol optical thickness t for major types of tropospheric aerosols including sulfate, dust, organic carbon (OC), black carbon (BC), and sea salt. The GOCART model uses a dust emission algorithm that quantifies the dust source as a function of the degree of topographic depression, and a biomass burning emission source that includes seasonal and interannual variability based on satellite observations. Results presented here show that on global average, dust aerosol has the highest t at 500 nm (0.051), followed by sulfate (0.040), sea salt (0.027), OC (0.017), and BC (0.007). There are large geographical and seasonal variations of t, controlled mainly by emission, transport, and hygroscopic properties of aerosols. The model calculated total ts at 500 nm have been compared with the satellite retrieval products from the Total Ozone Mapping Spectrometer (TOMS) over both land and ocean and from the Advanced Very High Resolution Radiometer (AVHRR) over the ocean. The model reproduces most of the prominent features in the satellite data, with an overall agreement within a factor of 2 over the aerosol source areas and outflow regions. While there are clear differences among the satellite products, a major discrepancy between the model and the satellite data is that the model shows a stronger variation of t from source to remote regions. Quantitative comparison of model and satellite data is still difficult, due to the large uncertainties involved in deriving the t values by both the model and satellite retrieval, and by the inconsistency in physical and optical parameters used between the model and the satellite retrieval. The comparison of monthly averaged model results with the sun photometer network [Aerosol Robotics Network (AERONET)] measurements shows that the model reproduces the seasonal variations at most of the sites, especially the places where biomass burning or dust aerosol dominates.

Asthma and allergy in Albania and the UK

In the first phase of the International Study of Asthma and Allergies in Childhood, a large difference in occurrence of asthma symptoms was seen between children in Albania and the UK. We did skin-prick tests with various allergens and measured peak expiratory flow rate in about 1000 children from each country. A large difference in the proportion of exercise-induced bronchial reactivity was evident between children from Albania and the UK (0.8% vs 5.4%, respectively). However, the frequency of allergic sensitisation was closely similar (15.0% vs 17.8%, respectively). These results suggest that large geographical variations in asthma prevalence can arise without differences in frequency of atopy.

Prevalence of antimicrobial resistance in Streptococcus pneumoniae circulating in Italy: results of the Italian Epidemiological Observatory Survey (1997-1999).

The Italian Epidemiological Observatory (IEO), a surveillance program supported by the SmithKline Foundation, analyzed the susceptibility of 2,664 community-acquired respiratory Streptococcus pneumoniae derived from over 50 clinical microbiology laboratories during 1997-1999, against 21 antibiotics adopting a quantitative methodology. Throughout these years, total penicillin resistance varied from 14.3% to 10.2%. High-level resistance has remained stable, ranging from 3.8% to 4.1%, while a decrease in low-level resistance (from 10.3% to 6.1%) has been recorded. Lack of susceptibility to macrolides ranged from 29.1% in 1997 to 25.5% in 1999. Similar figures have also been observed with tetracycline and co-trimoxazole (rates of resistance around 30%). As expected, large geographical variations in resistance rates were found for all drugs. Amoxicillin and amoxicillin-clavulanate were 100% active on penicillin-intermediate isolates. Injectable third-generation cephalosporins and carbapenems were also capable of inhibiting a large proportion of these microorganisms. Rifampin was the most potent non-beta-lactam compound tested. In contrast to the situation prevailing elsewhere, in Italian children (aged 0-5 years) presenting with respiratory conditions, the total rate of penicillin resistance (3%) was lower than that shown by the adult population (10.9%). However, lack of susceptibility to macrolides, tetracycline, and cotrimoxazole (35%, 41%, 44%) was more incident in pediatric than in adult patients (25%, 26%, 28% respectively). Strains recovered from blood in 1999 (67) were much more susceptible to penicillin (98.5%) than respiratory pneumococci (89.8%), whereas macrolides, tetracycline, and cotrimoxazole were consistently less active (75%, 67%, 64%).

Defining the importance of including transient ecosystem responses to simulate C-cycle dynamics in a global change model

Summary The ability of plant species to migrate is one of the critical issues in assessing accurately the future response of the terrestrial biosphere to climate change. This ability is confined by both natural and human-induced changes in land cover. In this paper we present land-cover and Carbon (C) cycle models designed to simulate the biospheric consequences of different types of land-cover changes. These models, imbedded in the larger integrated assessment model IMAGE 2, were used to demonstrate the importance of considering spatial aspects for global C-cycle modelling. A gradual-migration, an unlimited-migration and a no-migration case were compared to show the range of possible consequences. Major differences between these cases were simulated for land-cover patterns and the carbon budget. A large geographical variation in the biospheric response was also simulated. The strongest response was simulated in high-latitude regions, especially for the migration cases in which land-cover changes were permitted. In low-latitudes regions the differences between the migration cases were smaller, mainly due to the effects of land-use changes. The geographical variation among, and the different responses, the migration cases clearly demonstrate how essential it is to assess biospheric responses to climate change and land use simultaneously. Moreover, it also shows the urgent need for enhanced understanding of spatial and temporal dynamics of the biospheric responses.

Recent Trends of Minimum and Maximum Surface Temperatures over Eastern Africa

This study investigated recent trends in the mean surface minimum and maximum air temperatures over eastern Africa by use of both graphical and statistical techniques. Daily records for 71 stations for the period 1939-92 were used. Attempts were also made to associate the temperature characteristics with the anomalies in the major systems that control the climate of the region including the El Nino-Southern Oscillation (ENSO), the quasi-biennial oscillation, and the prevailing convective processes represented by the outgoing longwave radiation. The northern part of the study region generally indicated nighttime warming and daytime cooling in recent years. The trend patterns were, however, reversed at coastal and lake areas. The Mozambique channel region showed cooling during both nighttime and daytime. There were thus large geographical and temporal variations in the observed trends, with some neighboring locations at times indicating opposite trends. A significant feature in the temperature variability patterns was the recurrence of extreme values. Such recurrences were significantly correlated with the patterns of convective activities, especially ENSO, cloudiness, and above/below normal rainfall. Although some of the variations in the trend patterns could be attributed to urbanization and land use patterns, such effects were not delineated in the current study.

Clinical radiation doses for spinal cord: the 1998 international questionnaire

Background and purpose: Emmanuel van der Schueren gave a keynote lecture at the 1988 ASTRO annual conference pointing out that the spinal cord ‘tolerance doses’ then prescribed were probably unnecessarily cautious, resulting in probable underdosing of some tumours. This lecture was supported both by an international questionnaire which he and two of the present authors had conducted, and by animal experimental data. In 1997 he initiated a 10-year follow-up questionnaire, the results of which are summarised here. Materials and methods: The present report analyses the change in prescriptions from 1988 to 1998 and the variation in prescriptions among various regions of the World. Results and conclusions: The main conclusion is that prescribed dose levels have increased significantly in this period. Large geographical variations still exist. Among responders who use a formula to correct for changed dose per fraction, 90% are now using the linear-quadratic model vs. 33% in 1988. The current status of clinically acceptable doses to spinal cord in 2-Gy fractions is discussed briefly. Further details from the responses to the 1998 questionnaire will be presented in another publication.

Prostate cancer registration in four Swedish regions 1996-- differences in incidence, age structure and management.

In 1996 registration of prostate cancer in four of the six Swedish regions was started to facilitate evaluation of geographical variations in incidence and treatment. For all cases of prostate cancer, personal identification number, tumour stage, tumour grade and primary treatment were registered. In the four regions covered by the register, 3541 cases of prostate cancer were registered. Altogether there were 5795 cases of prostate cancer diagnosed in Sweden the same year. The age-standardized incidence varied from 89/100000 to 169/100000 among counties. The proportion of localized tumours correlated positively to the incidence (p < 0.05) and negatively to mean age at diagnosis (p < 0.01). There was also a significant positive correlation between the proportion of localized tumours and the percentage of patients given curative treatment. All registered variables showed large geographical variations, especially concerning percentage of T1c tumours, treatment of localized tumours and choice of palliative treatment. Diagnostic activity varied considerably among counties, resulting in large variation in age-standardized incidence. High incidence is associated with a larger proportion of localized tumours, which, in turn, is associated with early age at diagnosis. In counties where a policy of detecting tumours early is practised, curative treatment is also given more often. Treatment of localized tumours and preference for palliative treatment seem to depend on local traditions. The lack of cytological and histopathological standards makes geographical comparisons based on tumour grade impossible.

Intra-lake Variation in Maturity, Fecundity, and Spawning of Slimy Sculpins ( Cottus cognatus) in Southern Lake Ontario

Knowledge of the spawning cycle and factors affecting fecundity of slimy sculpins (Cottus cognatus) are important in understanding the population dynamics of this species in large lake systems, like Lake Ontario. Fecundity and the spawning cycle of slimy sculpins were described from samples of slimy sculpins and their egg masses collected with bottom trawls during four annual surveys, April to October, 1988 to 1994. Incidence of gravid females and collections of their egg masses indicated that spawning by slimy sculpins likely occurred from late April to mid October in Lake Ontario. Protracted spawning by slimy sculpins in Lake Ontario is probably a function of the annual water temperature cycle at various depths. Mean length of gravid females was inversely related to density of slimy sculpins. Fecundity ranged from 55 to 1,157 eggs among fish 55 to 127 mm long, and for similar-sized fish, fecundity was inversely related to density of slimy sculpins. Fecundity was about 50% higher at Olcott, where population indices of slimy sculpins were low, compared with Nine Mile Point where indices were much higher. Somatic weight or total length were both good predictors of fecundity. Lipid content of slimy sculpins was lower in an area of high sculpin abundance than in an area of low sculpin abundance, suggesting that fecundity was a function of density-dependent food availability. In large aquatic ecosystems, samples from more than one area may be necessary to describe fecundity of a sedentary species like slimy sculpin, especially if fish densities vary considerably among geographic areas. Large geographic variations in fecundity may be an indicator of spatial imbalance of a species with its prey. Low fecundity may be a compensatory response of slimy sculpins to low food supplies, thereby limiting population growth.

Epidemiological aspects of ageing.

A major societal challenge is to improve quality of life and prevent or reduce disability and dependency in an ageing population. Increasing age is associated with increasing risk of disability and loss of independence, due to functional impairments such as loss of mobility, hearing and vision; a major issue must be how far disability can be prevented. Ageing is associated with loss of bone tissue, reduction in muscle mass, reduced respiratory function, decline in cognitive function, rise in blood pressure and macular degeneration which predispose to disabling conditions such as osteoporosis, heart disease, dementia and blindness. However, there are considerable variations in different communities in terms of the rate of age-related decline. Large geographic and secular variations in the age-adjusted incidence of major chronic diseases such as stroke, hip fracture, coronary heart disease, cancer, visual loss from cataract, glaucoma and macular degeneration suggest strong environmental determinants in diet, physical activity and smoking habit. The evidence suggests that a substantial proportion of chronic disabling conditions associated with ageing are preventable, or at least postponable and not an inevitable accompaniment of growing old. Postponement or prevention of these conditions may not only increase longevity, but, more importantly, reduce the period of illnesses such that the majority of older persons may live high-quality lives, free of disability, until very shortly before death. We need to understand better the factors influencing the onset of age-related disability in the population, so that we have appropriate strategies to maintain optimal health in an ageing population.

Nutrient contents and concentrations in relation to growth of Picea abies and Fagus sylvatica along a European transect.

Mineral nutrition of Norway spruce (Picea abies (L.) Karst.) and beech (Fagus sylvatica L.) was investigated along a transect extending from northern Sweden to central Italy. Nitrogen (N) concentrations of needles and leaves in stands growing on acid soils did not differ significantly between central Italy and southern Sweden (1.0 +/- 0.1 mmol N g(-1) for needles and 1.9 +/- 0.14 mmol N g(-1) for leaves). In both species, foliar N concentrations were highest in Germany (1.2 mmol N g(-1) for needles and 2.0 mmol N g(-1) for leaves) and decreased by 50% toward northern Sweden (0.5 mmol N g(-1)). Both species showed constant S/N and P/N ratios along the transect. Calcium, K and Mg concentrations generally reflected local soil conditions; however, Mg concentrations reached deficiency values in Germany. Leaf area per unit dry weight varied significantly along the transect with lowest values for Norway spruce recorded in northern Sweden and Italy (3.4 m(2) kg(-1)) and a maximum in central Europe (4.7 m(2) kg(-1)). A similar pattern was observed for beech. Despite the low variation in foliar N concentrations on the large geographic scale, local and regional variations in N concentrations equalled or exceeded the variation along the entire continental transect. Furthermore, nutrient contents (i.e., nutrient concentration x dry weight per needle or leaf) showed a greater variation than nutrient concentrations along the transect. Nitrogen contents of Norway spruce needles reached minimum values in northern Sweden (2.4 micro mol N needle(-1)) and maximum values in Denmark (5.0 micro mol N needle(-1)). The N content of beech leaves was highest in Denmark (242 micro mol N leaf(-1)). At the German site, foliar N content rather than N concentration reflected the seasonal dynamics of foliar growth and N storage of the two species. During foliage expansion, there was an initial rapid increase in N content and a decrease in N concentration. This pattern lasted for about 2 weeks after bud break and was followed by 6 weeks during which dry weight and N content of the foliage increased, resulting in a further decrease in N concentration. During summer, dry weight and N content of mature needles of Norway spruce increased further to reach a maximum in autumn, whereas N concentration remained constant. In spring, reallocation of N from 1- and 2-year-old needles was 1.5 and 1.0 micro mol N needle(-1), respectively. This remobilized N was a major source of N for the development of new needles, which had an N content of 1.5 micro mol N needle(-1) after bud break. The seasonal remobilization of N from old foliage decreased with increasing needle age. Needle N content and dry weight decreased progressively with age (1 micro mol N needle(-1) between age classes 2 and 5), whereas N concentrations remained constant. For Norway spruce, annual stemwood production was correlated with needle N content but not with foliar N concentration or with the total amount of N in the canopy. Interspecific and geographical differences in plant nutrition are discussed on the basis of competitive demands for C and N between growth of foliage and wood.

Phylogenetic analysis of thermal acclimation of the glycolytic enzymes in the genus Fundulus.

Physiological acclimation that alters enzyme activity can compensate for the effect of temperature on function and may be achieved by altering enzyme concentration. This study uses phylogenetic analyses to investigate the evolutionary history of and to test several hypotheses about acclimation responses among all the glycolytic enzymes. These hypotheses are that (1) acclimation increases enzyme concentration at lower temperatures to compensate for reduced activity; (2) equilibrium enzymes tend to show acclimation responses; and (3) acclimation responses are more common in species whose populations experience either large temporal or geographical temperature variations. Using maximal activities as indices of enzyme concentration, the presence of acclimation responses in all the glycolytic enzymes in the heart ventricle was determined for five species in the teleost genus Fundulus. Three of these species are distributed along the steep thermal cline of the North American Atlantic coast, and thus these species experience both seasonal and geographical variation in temperature. The other two species are found in the Gulf of Mexico and experience seasonal variation similar to the Atlantic species but no geographical variation in temperature. Two Atlantic coast species, Fundulus heteroclitus and Fundulus majalis, have unique derived acclimation responses. No derived acclimation responses occur in the Gulf species. A conserved response in hexokinase was observed within one subgenus comprising both Atlantic and Gulf species. In F. heteroclitus, enolase responded to acclimation, and in F majalis, aldolase, triphosphate isomerase, and lactate dehydrogenase had acclimation responses. These enzymes are equilibrium enzymes, and the concentrations of all of them increase at lower temperatures, which would compensate for the effect of temperature on enzyme activity. The compensatory changes all occur in the Atlantic species and may be a mechanism for species to expand their ranges. These data suggest that physiological acclimation is evolutionarily labile.

The geoepidemiology of primary biliary cirrhosis.

There are apparently large geographical and secular variations in the prevalence of primary biliary cirrhosis worldwide. Most studies suggest that the disease is most common in Northern Europe, particularly northern Britain and Scandinavia, and that the prevalence is increasing. This comprehensive review of the literature explores to what extent these variations could be real rather than artifactual due to lack of comparability among studies. The major design flaws are examined and guidelines for better practice are outlined. It is hoped that other researches will utilize these recommendations for future studies so that true variations can be identified and hypotheses regarding disease causation may be formulated and investigated. These guidelines include: stringent case inclusion criteria; definition of date of disease onset; well-defined study period, area and population; multiple case finding methods; rigorous tracing of all possible cases. Preliminary results of the authors' study using these guidelines are described and report a point prevalence of 235 per million population in 1994 in the north of England, the highest yet reported.

Regional variations in the utilization rate of vaginal and abdominal hysterectomies in the United Kingdom.

Large geographic variations in hysterectomy rates are well known; however, very little is known about geographic variations in the route of the procedure, i.e. whether it is performed abdominally or vaginally. We compared utilization rates for abdominal and vaginal hysterectomies for the 14 Regional Health Authorities of England, and Northern Ireland over a three-year period. Data were collected in the form of hospital episode statistics and small area analysis techniques were used to document regional variations. Large regional differences in the utilization of vaginal hysterectomies were recorded. Three areas in particular (Northern Ireland, Yorkshire and NW Thames) displayed high vaginal to abdominal ratios. Northern Ireland recorded the highest ratio (0.366), Mersey Regional Health Authority the lowest (0.139). The use of the vaginal route was found to increase with age, and was the most common route for the > 65 years age group. Despite an increasing volume of evidence advocating the use of the vaginal route, there appears to be a resistance to its use, except in older women. The role of physician practice style, and in particular group clinical judgement, is highlighted as being significantly involved in explaining the observed geographic variations.

Serologic association between human papillomavirus type 16 infection and esophageal cancer in Shaanxi Province, China.

The existence of large geographic variations in the prevalence of esophageal cancer in some countries, such as China, indicates that environmental risk factors may be important in the development of this disease. Some studies have implicated genital-mucosal strains of human papillomaviruses (HPVs) in the etiology of this cancer. We conducted a case-control study in Shaanxi Province, China, an area with a population at high risk for esophageal cancer, to assess the association of this disease with infection by HPV type 16 (HPV16), the most common cancer-associated genital-mucosal HPV type. Ninety individuals with esophageal cancer and 121 cancer-free control subjects were identified among the patients in two hospitals in Xi'an, Shaanxi Province. The control subjects were matched to the case patients on the basis of age and sex. Blood specimens were drawn from all study subjects, and serum was isolated by routine methods. The presence of HPV16 antibodies in serum samples was determined by use of an enzyme-linked immunosorbent assay (ELISA) that used baculovirus-derived HPV16 virus-like particles as the antigen. A similar ELISA that used bovine papillomavirus type 1 (BPV1) virus-like particles as the antigen controlled for the specificity of HPV16 seroreactivity. Data from the HPV16 and the BPV1 assays were normalized with respect to results obtained in each assay with a control serum of known HPV16 seroreactivity. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to examine the association between HPV16 seroreactivity and esophageal cancer. Reported P values are two-sided. The mean seroreactivity to HPV16 virus-like particles was significantly higher for the cancer patients than for the control subjects (mean value +/- standard deviation = 0.85 +/- 0.22 versus 0.74 +/- 0.18; P<.0001). When the cancer patients and control subjects were compared by sex and age groups, the differences in mean seroreactivity remained statistically significant. The difference in mean seroreactivity to BPV1 virus-like particles between cancer patients and control subjects was not statistically significant (0.81 +/- 0.28 versus 0.88 +/- 0.32; P = .12); this result was not altered when sex and age groups were compared. By use of a cutoff point for HPV16 seropositivity that was established in studies of cervical neoplasia, 24% of the cancer patients were seropositive compared with 7% of the control subjects, yielding a sex- and age-adjusted OR of 4.5 (95% CI = 1.8-11.9). In general, the OR for esophageal cancer increased with increasing HPV16 seroreactivity. HPV16 infection may be a risk factor for esophageal cancer. Further studies of the association between HPV16 infection and the incidence of esophageal cancer are needed.

Recreational fishing in Norway from 1970 to 1993: trends and geographical variation

Abstract Participation in recreational fishing by Norwegians and geographical differences in fishing behaviour in Norway were investigated from 1970 to 1993 by comparing results from several household surveys at the national level and in different municipalities. Approximately 50% of the adult population fish every year. Only slight changes in participation rates were observed between 1970–1993, but considerable local variation in rates of participation and type of fishing were found. Participation rates among people living in northern Norway and in rural municipalities was higher than among people living in southern Norway and urban citizens. Among people living in the capital city, Oslo, the rate of participation was particularly low. Recreational fishing in Norway includes angling as well as subsistence fishing. Large geographical variation in fishing, continuing urbanization and an increasing population of elderly people should be taken into account by managers when developing a recreational fisheries strategy for the future.

Predictions of climate changes caused by man-made emissions of greenhouse gases: A critical assessment

Abstract Predictions of the most advanced computer models of the changes in the global climate that may result from man-made emissions of greenhouse gases are described and assessed in the light of the uncertainties in future emissions and atmospheric concentrations of these gases, and of the limitations of the models Predictions of the globally averaged temperature rise, produced by the doubling of atmospheric carbon dioxide over 70 years, range from 1·3 to 2·6°C, on average about 0·3°C decade−1. The scattering of solar radiation by atmospheric aerosols is calculated to reduce this global warming to about 1·0°C or 0·2°C decade−1. Warming is predicted to occur everywhere but to be most marked in high latitudes of the Northern Hemisphere. Globally averaged precipitation is predicted to rise by a few per cent but with large geographical variations and areas of both increase and decrease. The largest increases are expected to occur in intertropical convergence zone, and in middle and high latitudes, especially in winter. Decreases are predicted in the subtropics. The best current estimate of the rise in sea level resulting from an annual increase of 1% p.a. of carbon dioxide is 4 cm decade−1.

Hospital characteristics, diagnoses, and staff reasons associated with use of seclusion and restraint.

Patterns of seclusion and restraint over a one-year period at 82 Veterans Affairs medical centers were examined to determine whether use of these interventions was influenced by hospital characteristics (such as geographic location, per diem cost, patient-staff ratio, and university affiliation), patient diagnoses, or reasons for use. For comparison, medical centers were grouped into seven geographic regions and into three frequency-of-use groups. Mean use rates and hospital characteristics were examined by rank correlational analysis. Among hospital characteristics, only geographic location was associated with differences in use of seclusion and restraint. Mean rates of use in the Pacific and Mid-Atlantic regions were significantly lower than those in other regions. Total hours of seclusion and restraint at the 20 highest-use centers differed from those at the 20 lowest-use centers by a factor of ten. Patients with schizophrenic disorders were secluded or restrained most frequently. Centers with the highest rates used these interventions most frequently for reasons not associated with violent or potentially violent behaviors. The large geographic variations in use of seclusion and restraint may be a function of different standards of practice or of different state laws.