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Temporal Trends (temporal + trend)
Selected AbstractsAccounting Conservatism and the Temporal Trends in Current Earnings' Ability to Predict Future Cash Flows versus Future Earnings: Evidence on the Trade-off between Relevance and ReliabilityCONTEMPORARY ACCOUNTING RESEARCH, Issue 2 2010SATI P. BANDYOPADHYAY M41; C23; D21; G38 This research reports that an increasing level of accounting conservatism over the 1973,2005 period is associated with: (1) an increase in the ability of current earnings to predict future cash flows and (2) a decrease in the ability of current earnings to predict future earnings. We also find that usefulness of earnings for explaining stock prices over book values is positively related to reliability but not to relevance. Our results hold for the constant and full samples in both in-sample and out-of-sample analyses and are robust to the use of alternative measures for relevance, reliability, earnings usefulness, and conservatism. Our findings about the relations among conservatism, relevance, reliability, and usefulness suggest a trade-off between relevance and reliability and seem to indicate that the adoption of an increasing number of conservative accounting standards has a possible adverse impact on earnings usefulness through a negative effect on reliability. [source] Monounsaturated Fatty Acid Intake by Children and Adults: Temporal Trends and Demographic DifferencesNUTRITION REVIEWS, Issue 4 2004Theresa A. Nicklas Dr.P.H. Epidemiologic evidence suggests that dietary monounsaturated fatty acids (MUFA) may have a beneficial health effect. Twenty-four-hour dietary intake data collected on 10-year-olds from 1978 to 1994 and on children and adults (ages 0,30 years) were examined for time, age, gender, ethnic, and geographic location differences in MUFA intake. Children's percent energy from MUFA decreased significantly from 1978 (14.1%) to 1994 (11.9%) with intake of oleic acid decreasing from 33.9 g/day (1973) to 25.7 g/day (1994). In 1994,96, percent energy from MUFA was 13% for children and adults aged 12 to 30 years, with 5% from palmitoleic acid and 93% from oleic acid. Males and blacks had significantly higher MUFA intake across all age groups than females and whites. Intakes of MUFA increased from 0 to 11 years of age to young adulthood (12,19 years), with no further increase at 20 to 30 years of age. Intakes of MUFA were lowest in the Northeast and highest in the Midwest. There were differences in food sources of MUFA by age group. For children 0 to 5 years of age, major sources were whole milk, peanut butter, 2% milk, and French fries; for children 6 to 11 years of age, major sources were whole milk, peanut butter, French fries, and 2% milk; for children 12 to 19 years of age, French fries, salty snacks, whole milk, and meat pizza were the major sources; for adults, French fries, whole milk, potato chips, and ground beef were the most common sources of MUFA. U.S. children and adults displayed temporal trends and demographic differences in intakes and food sources of MUFA. The implications of these changes and differences on biologic risk factors for specific chronic diseases warrant further investigation. [source] Temporal Trends in the Use of Drug-eluting Stents for Approved and Off-label Indications: A Longitudinal Analysis of a Large Multicenter Percutaneous Coronary Intervention RegistryCLINICAL CARDIOLOGY, Issue 2 2010Sarah K. Gualano MD Background We sought to examine the temporal variations in the rate of both bare-metal stent (BMS) and drug-eluting stent (DES) use for off-label indications after the reports of an increased risk of very late stent thrombosis in patients with DES at the 2006 meeting of the European Society of Cardiology (ESC). Hypothesis To determine whether the decrease in use of DES has affected both on and off-label indications. Methods The study cohort included patients undergoing coronary intervention in a large regional registry, the Blue Cross Blue Shield of Michigan Cardiovascular Consortium (BMC2). Patient demographic and clinical characteristics for patients with DES in the third quarter of 2006 (pre-ESC) were compared to those from the fourth quarter of 2008 (post-guideline changes). Use of DES for off-label indications, such as ST-segment elevation myocardial infarction (STEMI), in-stent restenosis (ISR), and saphenous vein graft (SVG) interventions, were evaluated. Results The overall deployment of DES fell sharply from 83% pre-ESC to a plateau of 58% in the first quarter of 2008. This corresponded to a rise in BMS use, while angioplasty procedures stayed the same. The STEMI subgroup showed the most dramatic change, from 78% to only 36%. Off-label use in SVGs showed a similar trend, from 74% to 43%. Drug-eluting stent deployment for ISR was less affected, though it also fell 25% (from 79%,56%). Conclusions The use of DES has fallen dramatically from June 2006 to December 2008, particularly for nonapproved indications. Our study provides a real-world assessment of contemporary change in DES use in response to the presentation of negative observational studies. Copyright © 2010 Wiley Periodicals, Inc. [source] Posidonia oceanica as a biomonitor of trace elements in the gulf of naples: Temporal trends by lepidochronology,ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 5 2004Stefania Ancora Abstract Levels of Hg, Cd, Pb, Cu, Zn, Fe, and Mn were assessed by using Posidonia oceanica as a bioindicator in the Gulf of Naples (southern Italy). Lepidochronology, which enables retroactive dating of scales and rhizomes of this seagrass, was combined with atomic spectrometry to assess temporal trends of trace elements in dated scales and rhizomes over a 10-year period. Lepidochronology occasionally has been used to monitor Hg in dated scales, but never has been used to determine concentrations of other trace elements in dated rhizomes. Data were compared between various structural parts of seagrass and between sampling sites. Concentrations of some elements found in dated scales or rhizomes showed a similar trend in most of the sites; increasing for Hg and Cu and decreasing for Pb, Fe, and Zn. Contaminant levels indicated by seagrass meadows varied from metal to metal. Concentrations of Hg, Cd, and Pb fell within the ranges measured in other areas considered to have low levels of heavy metal pollution, whereas Cu, Mn, and Zn had higher concentrations only in some years. However, on the basis of other studies, none of the sampling sites are considered to have high contamination levels. [source] Short-term climatic trends affect the temporal variability of macroinvertebrates in California ,Mediterranean' streamsFRESHWATER BIOLOGY, Issue 12 2007LEAH A. BÊCHE Summary 1. Long-term studies in ecology are essential for understanding natural variability and in interpreting responses to disturbances and human perturbations. We assessed the long-term variability, stability and persistence of macroinvertebrate communities by analysing data from three regions in northern California with a mediterranean-climate. During the study period, precipitation either increased or decreased, and extreme drought events occurred in each region. 2. Temporal trends in precipitation resulted in shifts from ,dry-year' communities, dominated by taxa adapted to no or low flow, to ,wet-year' communities dominated by taxa adapted to high flows. The abundance of chironomid larvae was an important driver of community change. Directional change in community composition occurred at all sites and was correlated with precipitation patterns, with more dramatic change occurring in smaller streams. 3. All communities exhibited high to moderate persistence (defined by the presence/absence of a species) and moderate to low stability (defined by changes in abundance) over the study period. Stability and persistence were correlated with climatic variation (precipitation and El Niño Southern Oscillation) and stream size. Stability and persistence increased as a result of drought in small streams (first-order) but decreased in larger streams (second- and third-order). Communities from the dry season were less stable than those from the wet-season. 4. This study demonstrates the importance of long-term studies in capturing the effects of and recovery from rare events, such as the prolonged and extreme droughts considered here. [source] Debating the greening vs. browning of the North American boreal forest: differences between satellite datasetsGLOBAL CHANGE BIOLOGY, Issue 2 2010DOMINGO ALCARAZ-SEGURA Abstract A number of remote sensing studies have evaluated the temporal trends of the normalized difference vegetation index (NDVI or vegetation greenness) in the North American boreal forest during the last two decades, often getting quite different results. To examine the effect that the use of different datasets might be having on the estimated trends, we compared the temporal trends of recently burned and unburned sites of boreal forest in central Canada calculated from two datasets: the Global Inventory, Monitoring, and Modeling Studies (GIMMS), which is the most commonly used 8 km dataset, and a new 1 km dataset developed by the Canadian Centre for Remote Sensing (CCRS). We compared the NDVI trends of both datasets along a fire severity gradient in order to evaluate the variance in regeneration rates. Temporal trends were calculated using the seasonal Mann,Kendall trend test, a rank-based, nonparametric test, which is robust against seasonality, nonnormality, heteroscedasticity, missing values, and serial dependence. The results showed contrasting NDVI trends between the CCRS and the GIMMS datasets. The CCRS dataset showed NDVI increases in all recently burned sites and in 50% of the unburned sites. Surprisingly, the GIMMS dataset did not capture the NDVI recovery in most burned sites and even showed NDVI declines in some burned sites one decade after fire. Between 50% and 75% of GIMMS pixels showed NDVI decreases in the unburned forest compared with <1% of CCRS pixels. Being the most broadly used dataset for monitoring ecosystem and carbon balance changes, the bias towards negative trends in the GIMMS dataset in the North American boreal forest has broad implications for the evaluation of vegetation and carbon dynamics in this region and globally. [source] Temporal dynamics of marginal steppic vegetation over a 26-year period of substantial environmental changeJOURNAL OF VEGETATION SCIENCE, Issue 2 2009Silvia Matesanz Abstract Questions: (1) Is climate a strong driver of vegetation dynamics, including interannual variation, in a range margin steppic community? (2) Are there long-term trends in cover and species richness in this community, and are these consistent across species groups and species within groups? (3) Can long-term trends in plant community data be related to variation in local climate over the last three decades? Location: A range margin steppic grassland community in central Germany. Methods: Cover, number and size of all individuals of all plant species present in three permanent 1-m2 plots were recorded in spring for 26 years (1980,2005). Climatic data for the study area were used to determine the best climatic predictor for each plant community, functional group and species variable (annual data and interannual variation) using best subsets regression. Results: April and autumn temperature showed the highest correlation with total cover and species richness and with interannual variations of cover and richness. However, key climate drivers differed between the five most abundant species. Similarly, total cover and number and cover of perennials significantly decreased over time, while no trend was found for the cover and number of annuals. However, within functional groups there were also contrasting species-specific responses. Long-term temperature increases and high interannual variability in both temperature and precipitation were strongly related to long-term trends and interannual variations in plant community data. Conclusions: Temporal trends in vegetation were strongly associated with temporal trends in climate at the study site, with key roles for autumn and spring temperature and precipitation. Dynamics of functional groups and species within groups and their relationships to changes in temperature and precipitation reveal complex long-term and interannual patterns that cannot be inferred from short-term studies with only one or a few individual species. Our results also highlight that responses detected at the functional group level may mask contrasting responses within functional groups. We discuss the implications of these findings for attempts to predict the future response of biodiversity to climate change. [source] Temporal trends in species composition and plant traits in natural grasslands of UruguayJOURNAL OF VEGETATION SCIENCE, Issue 3 2003Claudia Rodríguez Cabrera (1970) Abstract. We report the successional trends of the major life-forms (graminoids and forbs) in natural grasslands of Uruguay over a 9-yr period after the removal of domestic herbivores. For the whole community, species richness and diversity decreased over the successional period. In graminoids we observed clear temporal trajectories in floristic composition; the rate of floristic change decreased with time and was associated with a shift in plant traits. The exclusion of large herbivores promoted erect and tall grasses with narrow leaves and greater seed length, vegetative growth constrained to the cool season and increased frequency of annual species. Forbs did not show a clear temporal trend in species composition, but there was, nevertheless, a plot-specific species turnover of this functional group that was reflected in their attributes. Species spreading by means of rhizomes, with vegetative growth restricted to the warm season. Species with larger seeds increased under grazing exclusion, as did annual and nitrogen-fixing forbs. The floristic changes induced by cattle exclusion occurred early in the succession. This early high rate of change has practical implications for management and conservation programs of the natural grasslands of Uruguay. Additionally, the shift in plant traits may be helpful in devising simple indicators of grazing impact. [source] Temporal trends in new and recurrent oesophageal strictures in a Medicare populationALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 10 2007H. B. EL-SERAG SUMMARY Background, The widespread use of proton pump inhibitors for gastro-oesophageal reflux disease could result in a decline in new as well as recurrent gastro-oesophageal reflux disease-related oesophageal strictures. The temporal trends of strictures have not been examined in population-based studies. Methods, To examine the temporal trends in strictures, we calculated the age-adjusted incidence rates of new oesophageal strictures with or without oesophageal dilation in a sample of Medicare beneficiaries between 1992 and 2000. We also examined recurrent dilations recorded at least 3 months after a new stricture or the preceding recurrent stricture. Results, The age-adjusted rates for strictures accompanied with dilation declined by approximately 11% from 215 per million to 192 per million. New oesophageal strictures with dilation declined as a proportion of all upper endoscopies procedures (from 2.6% to 1.9%). Recurrent dilation within 1 year declined dramatically from 16% (9.5% CI: 12.5,20.3) in 1992 to 8% (95% CI: 4.43,10.62) in 2000. In multivariable proportional hazards model, there was a 30% risk reduction of recurrent oesophageal strictures. Conclusions, This population-based study indicates that the incidence of new as well as recurrent oesophageal strictures has been declining. In the face of rising incidence of other gastro-oesophageal reflux disease-related complications, it is important to understand the explanation of the present observations. [source] The response of mammals to forest fire and timber harvest in the North American boreal forestMAMMAL REVIEW, Issue 1 2005JASON T. FISHER ABSTRACT 1.,This paper reviews and compares the effects of forest fire and timber harvest on mammalian abundance and diversity, throughout successional time in the boreal forest of North America. 2.,Temporal trends in mammal abundance and diversity are generally similar for both harvested and burned stands, with some differences occurring in the initiation stage (0,10 years post disturbance). 3.,Small mammals and ungulates are most abundant immediately post disturbance, and decrease as stands age. Lynxes and hares utilize mid-successional stands, but are rare in young and old stands. Bats, arboreal sciurids and mustelids increase in abundance with stand age, and are most abundant in old growth. 4.,Substantial gaps in the data exist for carnivores; the response of these species to fire and harvest requires research, as predator,prey interactions can affect mammal community structure in both early and late successional stages. 5.,The lack of explicit treatment of in-stand forest structure post disturbance, in the reviewed literature made comparisons difficult. Where forest structure was considered, the presence of downed woody material, live residual trees and standing dead wood were shown to facilitate convergence of mammal communities to a pre-disturbance state for both disturbance types. 6.,Mammalian assemblages differed considerably between successional stages, emphasizing the importance of maintaining stands of each successional stage on the landscape when implementing forest management strategies. [source] Leaf age affects the seasonal pattern of photosynthetic capacityand net ecosystem exchange of carbon in a deciduous forestPLANT CELL & ENVIRONMENT, Issue 6 2001K. B. Wilson Abstract Temporal trends in photosynthetic capacity are a critical factorin determining the seasonality and magnitude of ecosystem carbonfluxes. At a mixed deciduous forest in the south-eastern United States (Walker Branch Watershed, Oak Ridge, TN, USA), we independently measured seasonal trends in photosynthetic capacity (using single-leaf gas exchange techniques) and the whole-canopycarbon flux (using the eddy covariance method). Soil respiration was also measured using chambers and an eddy covariance system beneath the canopy. These independent chamber and eddy covariance measurements, along with a biophysical model (CANOAK), areused to examine how leaf age affects the seasonal pattern of carbon uptake during the growing season. When the measured seasonality in photosynthetic capacity is representedin the CANOAK simulations, there is good agreement with the eddy covariance data on the seasonal trends in carbon uptake. Removing the temporal trends in the simulations by using the early season maximum value of photosynthetic capacity over the entire growing season over estimates the annual carbon uptake by about 300 g C m,2 year,1, halfthe total estimated annual net ecosystem exchange. Alternatively, use of the mean value of photosynthetic capacity incorrectly simulates the seasonality in carbon uptake by the forest. In addition to changes related to leaf development and senescence, photosynthetic capacitydecreased in the middle and late summer, even when leaf nitrogenwas essentially constant. When only these middle and late summer reductions were neglected in the model simulations, CANOAK still overestimated the carbon uptake by an amount comparable to 25% ofthe total annual net ecosystem exchange. [source] Work-related carpal tunnel syndrome in Washington State workers' compensation: Temporal trends, clinical practices, and disabilityAMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 4 2005William E. Daniell MD Abstract Background Work-related carpal tunnel syndrome (CTS) is a leading cause of disability. There is a need for information about temporal trends, clinical practices, and treatment outcomes. Methods A population based, retrospective cohort study of Washington State workers' compensation claims for CTS was initiated focusing on claims filed during 1990,1994, followed through 2000 (n,=,16,710). Results Half of the claims were filed for conditions other than CTS, but were eventually identified to be or include CTS. The first CTS diagnosis occurred more than 3 months after claim filing in 20% of claims. The longer that the CTS diagnosis occurred after claim filing, the more likely that CTS was accompanied by other problems, and disability tended to be longer. Conclusions Making an accurate diagnosis of CTS and initiating appropriate actions earlier than might otherwise occur could reduce the disability and costs in a large fraction of claims that are ultimately determined to involve CTS. © 2005 Wiley-Liss, Inc. [source] Temporal trends and misclassification in residential 60 Hz magnetic field measurementsBIOELECTROMAGNETICS, Issue 3 2002Robert S. Banks Abstract This research addressed the question of how well measurement data collected during a single visit, made at an arbitrary hour of day, day of week, and season, estimate longer term residential 60 Hz magnetic field levels. We made repeat spot and 24 h measurements in 51 children's home, located in the Detroit, MI, and the Minneapolis-St. Paul, MN metropolitan areas, on a regular bimonthly schedule over a 1 year period, as well as a single 2 week measurement, for total of eight visits, producing 21 days of data for each residence. We defined the long term estimate (LTE) as the geometric mean of all available 24 h geometric means from the first six bimonthly visits. The LTE served as the reference level for assessing seasonal, day of week, and diurnal effects, as well as the potential for misclassification. We found a small, but statistically significant (P,<,.05), seasonal effect, with levels approximately 3% lower than the LTE in the spring and about 4% greater during the summer. No effect was found for day of week. However, we did find a systematic and appreciable diurnal effect, suggesting that, for example, an evening spot measurement may overestimate the LTE by 20% or more. We also assessed how well the 24 h measurement from the last visit, which was not used in calculation of the LTE, estimated the LTE. We found a high degree of correlation (r,=,.92) and fair to good agreement using four exposure categories (,,=,.53). Thus, the 24 h measurement appears to be a satisfactory LTE estimator. However, this finding must be interpreted with caution since considerable unexplained variability was present among the repeat 24 h measurements in about one-third of the homes. While the 2 week measurement does somewhat decrease exposure misclassification, its added intrusiveness and cost are likely to outweigh the improved precision. Bioelectromagnetics 23:196,205, 2002. © 2002 Wiley-Liss, Inc. [source] Trends in melanoma epidemiology suggest three different types of melanomaBRITISH JOURNAL OF DERMATOLOGY, Issue 2 2007D. Lipsker Summary Background It has been suggested that the incidence of thin melanomas but not of thick tumours is rising in fair-skinned populations, although the reason for this discrepancy is not understood. Objectives To describe temporal trends in melanoma epidemiology in a limited part of France in order to confirm this observation and to provide an explanation. Methods This is a retrospective population- and academic centre-based study in which all melanomas diagnosed in the department of the Bas-Rhin, France between January 1980 and December 2004 were included. Results The study included 2094 melanomas diagnosed in 2020 patients. There was a steady increase in incidence of thin (< 1 mm) melanomas, mainly located on the trunk, and to a lesser extent in the head and neck region, in both sexes, and of intermediate (1,2 mm) melanomas in men. The incidence of intermediate melanomas in women and of thick (> 2 mm) melanomas, as well as mortality related to melanoma, remained stable. There was a steady decline of mean and median Breslow thickness. The 12 months median delay to diagnosis of thick tumours was significantly shorter than the 24 months delay to diagnosis of thin tumours. Conclusions Temporal trends suggest the existence of three unrelated types of melanoma: type I, thick melanomas, with stable incidence; type II, thin melanoma with a steady and important increase in incidence, mainly located on the trunk; and type III, melanoma with a slower increase in incidence, mainly located on the head and neck region. [source] Autumnal moth , why autumnal?ECOLOGICAL ENTOMOLOGY, Issue 6 2001Toomas Tammaru Summary 1. As for some other spring-feeding moths, adult flight of Epirrita autumnata (Lepidoptera: Geometridae) occurs in late autumn. Late-season flight is a result of a prolonged pupal period. Potential evolutionary explanations for this phenological pattern are evaluated. 2. In a laboratory rearing, there was a weak correlation between pupation date and the time of adult emergence. A substantial genetic difference in pupal period was found between two geographic populations. Adaptive evolution of eclosion time can thus be expected. 3. Metabolic costs of a prolonged pupal period were found to be moderate but still of some ecological significance. Pupal mortality is likely to form the main cost of the prolonged pupal period. 4. Mortality rates of adults, exposed in the field, showed a declining temporal trend from late summer to normal eclosion time in autumn. Lower predation pressure on adults may constitute the decisive selective advantage of late-season flight. It is suggested that ants, not birds, were the main predators responsible for the temporal trend. 5. Egg mortality was estimated to be low; it is thus unlikely that the late adult period is selected for to reduce the time during which eggs are exposed to predators. 6. In a laboratory experiment, oviposition success was maximal at the time of actual flight peak of E. autumnata, however penalties resulting from sub-optimal timing of oviposition remained limited. [source] The myth of plant species saturationECOLOGY LETTERS, Issue 4 2008Thomas J. Stohlgren Abstract Plant species assemblages, communities or regional floras might be termed ,saturated' when additional immigrant species are unsuccessful at establishing due to competitive exclusion or other inter-specific interactions, or when the immigration of species is off-set by extirpation of species. This is clearly not the case for state, regional or national floras in the USA where colonization (i.e. invasion by exotic species) exceeds extirpation by roughly a 24 to 1 margin. We report an alarming temporal trend in plant invasions in the Pacific Northwest over the past 100 years whereby counties highest in native species richness appear increasingly invaded over time. Despite the possibility of some increased awareness and reporting of native and exotic plant species in recent decades, historical records show a significant, consistent long-term increase in exotic species (number and frequency) at county, state and regional scales in the Pacific Northwest. Here, as in other regions of the country, colonization rates by exotic species are high and extirpation rates are negligible. The rates of species accumulation in space in multi-scale vegetation plots may provide some clues to the mechanisms of the invasion process from local to national scales. [source] Mobility and potential toxicity of sediment-bound metals in a tidal estuaryENVIRONMENTAL TOXICOLOGY, Issue 4 2005O. Geffard Abstract Sediment toxicity in the Gironde Estuary, France, a site contaminated by such trace metals as Cd, Cu, and Zn, was examined monthly from March to October 1997, using concurrently geochemical procedures to assess the mobility of contaminants and ecotoxicity tests with invertebrate larvae (the oyster Crassostrea gigas, the sea urchin Paracentrotus lividus, and the copepod Tigriopus brevicornis). Higher mobility of Cd than of Cu and Zn was shown by desorption tests. Both the gross concentrations of Cu and Zn in the sediment and the mobility of these metals showed a temporal evolution, and changes in the toxicity of the sediment to invertebrate larvae generally were observed concomitantly. Little damage was registered in the spring, and greater damage was found in the summer and fall. Positive correlations were shown between mortality in copepods or abnormalities in oyster larvae with the quantities of metals remobilized from sediment at pH 4. On the contrary, no clear temporal trend was shown for total PAH levels in sediment. These correlations and previous toxicological data suggest that sediment-bound metals, particularly Cu and Zn, possibly play a role in biological responses. © 2005 Wiley Periodicals, Inc. Environ Toxicol 20: 407,417, 2005. [source] Organophosphorus pesticides in storm-water runoff from southern California (USA)ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 8 2004Kenneth Schiff Abstract Large quantities of the organophosphorus (OP) pesticides diazinon and chlorpyrifos are applied to California (USA) watersheds every year, but few data are available on the sources of OP pesticides in urban watersheds. The goal of this study was to characterize diazinon and chlorpyrifos concentrations from different land uses indicative of source categories in urban southern California watersheds. This characterization included analysis of 128 runoff samples from eight different land uses over five storm events. Diazinon was consistently detected (93% of samples) during this study, whereas chlorpyrifos was not consistently detected (12% of samples). The mixed agricultural land use had the highest flow weighted mean (FWM) concentration of diazinon (4,076 ng/L), which exceeded the next-highest land-use categories (commercial and residential) by one to two orders of magnitude (324,99 ng/L, respectively). Open space had the lowest concentration of diazinon (<20 ng/L). Concentrations of diazinon at replicate land-use sites and during replicate storm events at the same site were highly variable. The difference in diazinon FWM concentrations among replicate sites ranged from 1.5-fold to 45-fold. The difference in diazinon FWM concentrations among storms at the same site ranged from 1.25-fold to 30-fold. Part of this variability is a response to the temporal patterns observed within a storm event. The majority of land-use site-events had peak concentrations before peak flow indicating a first-flush effect, but this was not always a predictable temporal trend. The first-flush effect was rarely evident in terms of mass loadings because flows can range orders of magnitude during a single event in highly impervious urban watersheds. Flow variability thus overwhelms the variability in diazinon concentrations attributable to the first-flush effect. [source] Predicting intra-urban variation in air pollution concentrations with complex spatio-temporal dependencies,ENVIRONMETRICS, Issue 6 2010Adam A. Szpiro Abstract We describe a methodology for assigning individual estimates of long-term average air pollution concentrations that accounts for a complex spatio-temporal correlation structure and can accommodate spatio-temporally misaligned observations. This methodology has been developed as part of the Multi-Ethnic Study of Atherosclerosis and Air Pollution (MESA Air), a prospective cohort study funded by the US EPA to investigate the relationship between chronic exposure to air pollution and cardiovascular disease. Our hierarchical model decomposes the space--time field into a "mean" that includes dependence on covariates and spatially varying seasonal and long-term trends and a "residual" that accounts for spatially correlated deviations from the mean model. The model accommodates complex spatio-temporal patterns by characterizing the temporal trend at each location as a linear combination of empirically derived temporal basis functions, and embedding the spatial fields of coefficients for the basis functions in separate linear regression models with spatially correlated residuals (universal kriging). This approach allows us to implement a scalable single-stage estimation procedure that easily accommodates a significant number of missing observations at some monitoring locations. We apply the model to predict long-term average concentrations of oxides of nitrogen (NOx) from 2005 to 2007 in the Los Angeles area, based on data from 18 EPA Air Quality System regulatory monitors. The cross-validated IR2 is 0.67. The MESA Air study is also collecting additional concentration data as part of a supplementary monitoring campaign. We describe the sampling plan and demonstrate in a simulation study that the additional data will contribute to improved predictions of long-term average concentrations. Copyright © 2009 John Wiley & Sons, Ltd. [source] Projecting future N2O emissions from agricultural soils in BelgiumGLOBAL CHANGE BIOLOGY, Issue 1 2007CAROLINE ROELANDT Abstract This study analyses the spatial and temporal variability of N2O emissions from the agricultural soils of Belgium. Annual N2O emission rates are estimated with two statistical models, MCROPS and MGRASS, which take account of the impact of changes in land use, climate, and nitrogen-fertilization rate. The models are used to simulate the temporal trend of N2O emissions between 1990 and 2050 for a 10, latitude and longitude grid. The results are also aggregated to the regional and national scale to facilitate comparison with other studies and national inventories. Changes in climate and land use are derived from the quantitative scenarios developed by the ATEAM project based on the Intergovernmental Panel on Climate Change-Special Report on Emissions Scenarios (IPCC-SRES) storylines. The average N2O flux for Belgium was estimated to be 8.6 × 106 kg N2O-N yr,1 (STD = 2.1 × 106 kg N2O-N yr,1) for the period 1990,2000. Fluxes estimated for a single year (1996) give a reasonable agreement with published results at the national and regional scales for the same year. The scenario-based simulations of future N2O emissions show the strong influence of land-use change. The scenarios A1FI, B1 and B2 produce similar results between 2001 and 2050 with a national emission rate in 2050 of 11.9 × 106 kg N2O-N yr,1. The A2 scenario, however, is very sensitive to the reduction in agricultural land areas (,14% compared with the 1990 baseline), which results in a reduced emission rate in 2050 of 8.3 × 106 kg N2O-N yr,1. Neither the climatic change scenarios nor the reduction in nitrogen fertilization rate could explain these results leading to the conclusion that N2O emissions from Belgian agricultural soils will be more markedly affected by changes in agricultural land areas. [source] The decline of Common Kestrels Falco tinnunculus in a forested area of northern England: the role of predation by Northern Goshawks Accipiter gentilisIBIS, Issue 3 2003S. J. Petty We have previously documented the decline of the Common Kestrel Falco tinnunculus over a 23-year period in a large coniferous forest in northern England. Kestrels fed predominantly on Field Voles Microtus agrestis, which were most abundant in young plantations (1,11 years old). Over the 23 years, voles remained abundant in the study area, but their numbers fluctuated cyclically. Here we consider whether the decline of Kestrels was linked to predation by Northern Goshawk Accipiter gentilis. Goshawks first bred in the study area in 1973 and increased until 1989, after which numbers stabilized. We use a number of approaches to explore the role of Goshawk predation, all of which are correlative, but independent. First, there was a significant negative relationship between Kestrel and Goshawk numbers after controlling for a decline in vole habitat. Short-eared Owls Asio flammeus, which also hunt by day, declined over the same period as Kestrels. Second, numbers of Tawny Owl Strix aluco and Long-eared Owl Asio otus did not decline as Goshawk numbers increased. These two species are also vole-dependent, but active by night, and less vulnerable to Goshawk attack. Third, six species of raptor comprised 4.5% of 5445 Goshawk prey items during the breeding season, but more Kestrels were killed than the combined total of all other raptors. Goshawks not only killed many adult Kestrels in early spring, prior to breeding, when it would have most impact on population levels, but there was also a temporal trend for predation on Kestrels to be inversely density-dependent. Finally, we estimated that Goshawks removed more Kestrels than were recorded each spring in the study area. We interpreted this as indicating that immigrant Kestrels were being removed continually, mostly before they could breed. We conclude that the decline of Kestrels (and possibly Short-eared Owls) was mainly due to predation by Goshawks. This study provides some of the strongest evidence yet of the role of predation in the hierarchical structuring of raptor communities. [source] Rapidly increasing incidence of papillary serous carcinoma of the peritoneum in the United States: Fact or artifact?,INTERNATIONAL JOURNAL OF CANCER, Issue 9 2009Marc T. Goodman Abstract Papillary serous carcinoma of the peritoneum (PSCP) has been recognized for almost 5 decades, but little is known about the etiology or pathogenesis of this uncommon malignancy. The objective of this analysis was to examine trends in the incidence of PSCP in the United States. Invasive PSCP cases (N = 4,389) were identified through 24 population-based registries in the United States during the period 1995-2004. Incidence rates were calculated per million population. PSCP is a disease of older women, with few cases diagnosed before the age of 40 years. The incidence of PSCP was 64% lower among black women and 47% lower among Asian-Pacific Islander women compared with white women. Rates among Hispanic women were 39% lower than among non-Hispanic women. The majority of PSCP (68%) was diagnosed at a distant stage, underscoring the difficulty of diagnosing this malignancy. The incidence of PSCP has increased dramatically during the past decade in the United States with the greatest rise (>13% per year) among non-Hispanic and white women. This trend was more pronounced among older women and women with early stage disease. The incidence of PSCP shows substantial racial and ethnic diversity. The increase in the rate of PSCP among all racial and ethnic groups during the 10-year observation period is cause for some alarm. Although the reason for this temporal trend is unknown, some of the increase may be attributable to reclassification of ovarian carcinoma to the peritoneum. © 2008 Wiley-Liss, Inc. [source] A Temporal Analysis of Earnings Surprises: Profits versus LossesJOURNAL OF ACCOUNTING RESEARCH, Issue 2 2001Lawrence D. Brown I show that median earnings surprise has shifted rightward from small negative (miss analyst estimates by a small amount) to zero (meet analyst estimates exactly) to small positive (beat analyst estimates by a small amount) during the 16 years, 1984 to 1999. I show that a rightward temporal shift in median surprise from negative to positive describes earnings, but neither profits nor losses. Median profit surprise shifts within the positive quadrant, from zero to one cent per share. Median loss surprise shifts within the negative quadrant from extreme negative (about -33 cents per share) to zero. I show that the median surprise for profits exceeds that for losses in every year. I document significant positive temporal trends in both meet and beat analyst estimates for both profits and losses, but I find a greater frequency of profits that either meet or beat analyst estimates in every year. I find a significant positive temporal trend in positive profits that are "a little bit of good news," and a significant negative temporal trend in managers who report losses that are an "extreme amount of bad news." My results are robust to the four internal validity threats I consider,namely temporal changes in: (1) analyst forecast accuracy, (2) the mix of earnings of one sign preceded by earnings of another sign four quarters ago, (3) the timeliness of the most recent analyst forecast, and (4) the I/B/E/S definition of actual earnings. I find that managers of growth firms are relatively more likely than managers of value firms to report good news profits. I show that when they do report positive profit surprises, managers of growth firms are more likely to report "a little bit of good news" in every year. [source] Effects of culling on spatial associations of Mycobacterium bovis infections in badgers and cattleJOURNAL OF APPLIED ECOLOGY, Issue 5 2007HELEN E JENKINS Summary 1Bovine tuberculosis (TB), caused by Mycobacterium bovis, has serious consequences for Britain's cattle industry. European badgers (Meles meles) can transmit infection to cattle, and for many years the British government culled badgers in a series of attempts to reduce cattle infections. 2We investigated the impact of badger culling on the spatial distribution of M. bovis infection in badger and cattle populations in replicated areas in England. 3M. bovis infection was significantly clustered within badger populations, but clustering was reduced when culls were repeated across wide areas. A significant spatial association between M. bovis infections in badgers and cattle herds likewise declined across successive culls. These patterns are consistent with evidence that badgers are less territorial and range more widely in culled areas, allowing transmission to occur over greater distances. 4Prior to culling, M. bovis infections were clustered within cattle populations. Where badger culling was localised, and in unculled areas just outside widespread culling areas, cattle infections became less spatially clustered as badger culling was repeated. This is consistent with expanded badger ranging observed in these areas. 5In contrast, clustering of infection in cattle persisted over time on lands where badgers were repeatedly culled over wide areas. While this lack of a temporal trend must be interpreted with caution, it might reflect persistent infection within, and continued transmission between, cattle herds in areas where transmission from badgers to cattle had been reduced by badger culling. Continued spatial association of infections in cattle and badgers in such areas might partly reflect transmission from cattle. 6Synthesis and applications: Our findings confirm that badger culling can prompt spatial spread of M. bovis infection, a phenomenon likely to undermine the utility of this approach as a disease control measure. Possible evidence of transmission from cattle, both to other cattle and to badgers, suggests that improved cattle controls might yield multiple benefits for TB management. [source] Spatial and temporal variability in seed dynamics of machair sand dune plant communities, the Outer Hebrides, ScotlandJOURNAL OF BIOGEOGRAPHY, Issue 5 2001N. W. Owen Aim The subjects of seed banks and seed rain represent comparatively neglected areas of biogeography, yet at the community scale, exhibit interesting patterns in both space and time. This paper describes the seed bank and seed rain characteristics of the machair sand dune communities of the Outer Hebrides. As well as looking at individual species distributions and variability, the seed banks and seed rain are examined in terms of their detailed subcommunity composition and its local spatial and temporal variation. The machair plant (sub)communities show extensive degrees of anthropogenic modification because of past and present agricultural management, including cultivation for cereals over wide areas and for potatoes in large numbers of ,lazy beds' or small patches. Thus over the historical period, large areas of machair have undergone regular ploughing and cultivation, which have provided the opportunity for a patchwork of secondary succession to occur. This pattern continues to the present day. Furthermore, most other non-cultivated plant (sub)communities are intensively grazed, primarily by cattle and also by sheep and rabbits. Location South Uist, the Outer Hebrides, north-west Scotland. Methods At two carefully selected locations, a range of these various successional subcommunities have been sampled for their seed banks, by taking cores and for their seed rain, by using specially designed traps located where each seed bank sample was removed. This paired sampling strategy allowed direct comparison of the seed bank and the seed rain. Both individual species distributions and the community assemblages of seed bank/seed rain species are examined in space and time using techniques of numerical classification [two-way indicator species analysis (TWINSPAN)] and ordination [detrended correspondence analysis (DCA)]. Results and conclusions There is considerable heterogeneity within and between machair subcommunities in terms of seed bank and seed rain characteristics. The soil seed banks and seed rain of the agriculturally disturbed machair subcommunities are consistently more dense and more species rich than non-cultivated areas of the machair. Overall, machair seed banks are small and stable with no discernible seasonal trends in either size or species composition. In contrast, seed rain on the machair is characterized by a distinct temporal trend. Both seed banks and seed rain are potentially very poor sources of propagules for recolonization following disturbance, indicating that the majority of revegetation following anthropogenic and/or environmental interference is through vegetative reproduction. [source] Deterioration of Organization in the First Minutes of Atrial Fibrillation: A Beat-to-Beat Analysis of Cycle Length and Wave SimilarityJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 1 2007FLAVIA RAVELLI Ph.D. Introduction: It has been recently suggested that many episodes of atrial fibrillation (AF) may be partially organized at the onset and thus more suitable for antitachycardia pacing therapy. Nevertheless, the time course of organization in the first minutes of AF has not been quantified yet. Methods and Results: Twenty episodes of paroxysmal AF were studied. Electrograms were recorded from the right atrium (RA), distal (CSd), and proximal coronary sinus (CSp). The time course of AF cycle length (AFCL) and the regularity of wave morphology (similarity index S) were beat-to-beat measured at each recording site during the first 7 minutes of AF. AFCL and S showed a decreasing trend after the onset of AF. AFCL decreased from 208 ± 31 to 171 ± 21 msec (P < 0.001), from 206 ± 40 to 169 ± 23 msec (P < 0.001) and from 190 ± 42 to 152 ± 18 msec (P < 0.05), respectively, in RA, CSd, and CSp. Similarly, the similarity index decreased in CSd from 0.37 ± 0.27 to 0.12 ± 0.09 (P < 0.01) and in RA from 0.40 ± 0.18 to 0.17 ± 0.16 (P < 0.001). The 80% of the decrease occurred during the first 3 minutes of the arrhythmia, while after this time both cycle length and similarity index did not change significantly anymore. Conversely, the electrical activity in CSp was highly disorganized (S = 0.05 ± 0.03) even in the first minute of AF, and no decreasing temporal trend was observed. Conclusion: Higher levels of organization and longer fibrillation intervals exist at the onset of AF. The degree of organization of the electrical activity decays within less than 3 minutes. Since antitachycardia pacing success rate increases with high levels of organization, these results suggest an early delivery of pacing treatment. [source] Demographic analysis of dormancy and survival in the terrestrial orchid Cypripedium reginaeJOURNAL OF ECOLOGY, Issue 4 2004MARC KÉRY Summary 1We use capture-recapture models to estimate the fraction of dormant ramets, survival and state transition rates, and to identify factors affecting these rates, for the terrestrial orchid Cypripedium reginae. We studied two populations in West Virginia, USA, for 11 years and investigated relationships between grazing and demography. Abe Run's population was small, with moderate herbivory by deer and relatively constant population size. The population at Big Draft was of medium size, with heavy deer grazing, and a sharply declining number of flowering plants up to the spring before our study started, when the population was fenced. 2We observed dormant episodes lasting from 1 to 4 years. At Abe Run and Big Draft, 32.5% and 7.4% of ramets, respectively, were dormant at least once during the study period for an average of 1.6 and 1.3 years, respectively. We estimated the annual fraction of ramets in the dormant state at 12.3% (95% CI 9.5,15.8%) at Abe Run and at 1.8% (95% CI 1.2,2.6%) at Big Draft. Transition rates between the dormant, vegetative and flowering life-states did not vary between years in either population. Most surviving ramets remained in the same state from one year to the next. Survival rates were constant at Abe Run (0.96, 95% CI 0.93,0.97), but varied between years at Big Draft (0.89,0.99, mean 0.95). 3At Big Draft, we found neither a temporal trend in survival after cessation of grazing, nor relationships between survival and the number of spring frost days or cumulative precipitation during the current or the previous 12 months. However, analysis of precipitation on a 3-month basis revealed a positive relationship between survival and precipitation during the spring (March,May) of the previous year. 4Relationship between climate and the population dynamics of orchids may have to be studied with a fine temporal resolution, and considering possible time lags. Capture-recapture modelling provides a comprehensive and flexible framework for demographic analysis of plants with dormancy. [source] Temporal trends in species composition and plant traits in natural grasslands of UruguayJOURNAL OF VEGETATION SCIENCE, Issue 3 2003Claudia Rodríguez Cabrera (1970) Abstract. We report the successional trends of the major life-forms (graminoids and forbs) in natural grasslands of Uruguay over a 9-yr period after the removal of domestic herbivores. For the whole community, species richness and diversity decreased over the successional period. In graminoids we observed clear temporal trajectories in floristic composition; the rate of floristic change decreased with time and was associated with a shift in plant traits. The exclusion of large herbivores promoted erect and tall grasses with narrow leaves and greater seed length, vegetative growth constrained to the cool season and increased frequency of annual species. Forbs did not show a clear temporal trend in species composition, but there was, nevertheless, a plot-specific species turnover of this functional group that was reflected in their attributes. Species spreading by means of rhizomes, with vegetative growth restricted to the warm season. Species with larger seeds increased under grazing exclusion, as did annual and nitrogen-fixing forbs. The floristic changes induced by cattle exclusion occurred early in the succession. This early high rate of change has practical implications for management and conservation programs of the natural grasslands of Uruguay. Additionally, the shift in plant traits may be helpful in devising simple indicators of grazing impact. [source] Does second-to-fourth digit length ratio (2D:4D) predict age at menarche in women?AMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 3 2010Samuli Helle Prenatal steroid levels, estimated as the ratio of second-to-fourth digit length (2D:4D), have been related to reproductive success in women, but direct associations between 2D:4D and physiological measures of fertility remain rare. A recent study reported that lower, masculinized right hand 2D:4D was correlated with delayed age at menarche in women. We addressed this question by investigating whether 2D:4D was associated with recalled age at menarche in 282 post-reproductive Finnish women, using Cox regression model that controlled for a woman's sibling composition, urban or rural residence and temporal trend in menarcheal age. We found no evidence that neither the 2D:4D of the right nor the left hand were related to a woman's age at menarche among these Finnish women. Am. J. Hum. Biol., 2010. © 2009 Wiley-Liss, Inc. [source] Role of wild plant foods among late Holocene hunter-gatherers from Central and North Patagonia (South America): An approach from dental evidenceAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 4 2007Valeria Bernal Abstract This study evaluates the role of plant foods in the subsistence of hunter-gatherers that inhabited the Central East, Northwest, and Northeast Patagonia (Argentina) during the late Holocene (ca. 3,000,500 years BP). The goal of the present study is to assess the temporal variation of dental caries ratio and wear rate in skeletal samples to ascertain if the biological information supports the dietary shift toward greater consumption of wild plant foods around 1,500 years BP, suggested by other types of evidence. The authors registered caries, antemortem and postmortem tooth loss, and tooth wear from eight samples belonging to hunter-gatherers from Patagonia for which chronological sequences from early late Holocene (ca. 3,000,1,500 years BP) up to final late Holocene (ca. 1,500,500 years BP) are available. The results indicate that caries percentages in Patagonian samples fall within the range established for hunter-gatherers but there are significant geographical differences. In addition, caries ratio does not change significantly through time, so the amount of carbohydrates consumed seems to have remained fairly constant since 3,000 years BP. In contrast, there is a marked temporal trend toward the reduction of wear rates in the three areas, suggesting a faster rate in early late Holocene than in final late Holocene. These results would reflect a change to less hard and/or abrasive diets in the final late Holocene, probably owing to differences in food processing methods employed. 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