Changes In Long-term Rates Research Articles

Why Is the Mean Anomaly at Epoch Not Used in Tests of Non-Newtonian Gravity?

The mean anomaly at epoch η is one of the standard six Keplerian orbital elements in terms of which the motion of the two-body problem is parameterized. Along with the argument of pericenter ω, η experiences long-term rates of change induced, among other things, by general relativity and several modified models of gravity. Thus, in principle, it may be fruitfully adopted together with ω in several tests of post-Newtonian gravity performed with astronomical and astrophysical binary systems. This would allow us to enhance the gravitational signature we are interested in and to disentangle some competing disturbing effects acting as sources of systematic bias. Nonetheless, for some reasons unknown to the present author, η has never been used so far by astronomers in actual data reductions. This note aims to raise interest in the community about the possible practical use of such an orbital element or, at least, to induce experts in astronomical data processing to explicitly make clear if it is not possible to use η for testing gravitational models and, if this is the case, why.

Quantifying long-term rates of texture change on road networks

ABSTRACT Texture is required on pavements to provide safe and comfortable ride performance for users. This paper provides the first meaningful analysis of a long-term study of texture data obtained using TRACS (TRAffic Speed Condition Survey) at a site in the UK. TRACS data were collected annually, over a 2 km stretch of motorway from 1995 to 2019. A new data analysis approach utilising time series data with spectral analysis and spatial filtering procedures is presented. The results reveal that the approach enables legacy TRACS laser profile Sensor Measured Texture Depth (SMTD) data to be used to determine long term rates of change in road surface macrotexture. Thus, the technique has unlocked the potential for SMTD data collected annually for 7000 km of the Strategic Road Network in the UK, to inform road maintenance programmes by extrapolation. Additionally, results expose a systematic periodicity occurring each year within the SMTD data studied, corresponding to longitudinal oscillations with wavelengths between 33 and 62 m. The time-invariant periodicity of these oscillations suggests that it is ‘imprinted’ in the early life of the pavement. ‘Imprinting’ may theoretically arise with cyclic tyre loading applied by the suspension systems of heavy vehicles or during road construction.

Constraining the long-term lowering rates of shore platforms on volcanic islands in the East Sea of the Korean Peninsula, using cosmogenic 36Cl

The occurrence of global warming and concomitant rises in sea level means it is important to assess the vertical lowering rates and evolution of shore platforms. Most previous studies, however, were based on empirical measurements and limited to the decadal scale, implying there is great necessity to learn about long-term rates of change on rocky coasts. In particular, because it is relatively easy to monitor soft rocks such as chalk, there is little information about hard rocky coasts that consist of volcanic, igneous, and metamorphic rocks. In this study, we used cosmogenic 36Cl exposure dating to overcome the spatial and temporal limitations of previous studies that have restricted progress in rocky coast research. Results show that the exposure ages of samples collected from the shore platforms along volcanic islands in the middle of the East Sea (Sea of Japan) range from the mid-Holocene (ca. 4 ka) to the last century (ca. 0.1 ka). The large range in ages along the outer platform edges may be related to stochastic, differential, and mechanical wave erosion. We also calculated the rates of vertical lowering from the 36Cl concentrations of the platform surfaces, yielding a maximum rate, excluding outliers, of 0.68 mm/yr. The rates of vertical lowering inferred from the cosmogenic 36Cl abundances are comparable with previous empirical values, and will improve our understanding of the long-term evolution of rocky coasts.

Long-term rates of change in musculoskeletal aging and body composition: findings from the Health, Aging and Body Composition Study

Musculoskeletal disorders are common among older people. Preventive strategies require understanding of age-related changes in strength, function and body composition, including how they interrelate. We have described, and examined associations between, 9-year changes in these parameters among 2917 Health, Aging and Body Composition Study participants (aged 70–79 years). Appendicular lean mass (ALM), whole body fat mass and total hip BMD were ascertained using DXA; muscle strength by grip dynamometry; and muscle function by gait speed. For each characteristic annualised percentage changes were calculated; measures of conditional change (independent of baseline) were derived and their interrelationships were examined using Pearson correlations; proportion of variance at 9-year follow-up explained by baseline level was estimated; and mean trajectories in relation to age were estimated using linear mixed models. Analyses were stratified by sex. Median [lower quartile, upper quartile] annual percentage declines were grip strength (1.5 [0.0, 2.9]), gait speed (2.0 [0.6, 3.7]), ALM (0.7 [0.1, 1.4]), fat mass (0.4 [− 1.1, 1.9]) and hip BMD (0.5 [0.0, 1.1]). Declines were linear for ALM and accelerated over time for other characteristics. Most conditional change measures were positively correlated, most strongly between ALM, fat mass and hip BMD (r > 0.28). Proportion of variation at follow-up explained by baseline was lower for grip strength and gait speed (39–52%) than other characteristics (69–86%). Strength and function declined more rapidly, and were less correlated between baseline and follow-up, than measures of body composition. Therefore, broader intervention strategies to prevent loss of strength and function in later life are required as those targeting body composition alone may be insufficient.

Measuring Monetary Policy Surprises Using Text Mining: The Case of Korea

We propose a novel approach to measure monetary policy shocks using sentiment analy-\sis, which is relatively free from specification errors compared to VAR-identified shocks and allows time for a wider circle of market participants to digest information com-pared to shocks identified through intraday Fed futures data. We quantify the tones of news articles around 152 dates of Monetary Policy Board (MPB) meetings of the Bank of Korea (BOK) from 2005 to 2017 and then measure monetary policy surprises us-ing the changes of those tones following monetary policy announcements. We estimate its impact on asset prices and find that it better explains changes in long-term rates, while changes in the Bank of Korea’s base rate and VAR-identified monetary shocks are more closely associated with changes in short-term rates. Our result strongly suggests that a text mining approach to measure monetary policy surprises can be an useful complement to extract market expectations on future monetary policy.

Spatial distribution and extent of urban land cover control watershed-scale chloride retention

In some cold regions up to 97% of the chloride (Cl−) entering rivers and lakes is derived from road salts that are applied to impervious surfaces to maintain safe winter travel conditions. While a portion of the Cl− applied as road salt is quickly flushed into streams during melt events via overland flow and flow through storm sewer pipes, the remainder enters the subsurface. Previous studies of individual watersheds have shown that between 28 and 77% of the applied Cl− is retained on an annual basis, however a systematic evaluation of the spatial variability in Cl− retention and potential driving factors has not been carried out. Here we used a mass balance approach to estimate annual Cl− retention in 11 watersheds located in southern Ontario, Canada, which span a gradient of urbanization. We evaluated the influence of multiple landscape variables on the magnitude of Cl− retention as well as the long-term rate of change in stream Cl−concentration for the same systems. We found that mean annual Cl− retention ranged from 40 to 90% and was higher for less urbanized watersheds and for watersheds with urban areas located farther from the stream outlet. This result suggests that less urbanized watersheds and ones with longer flow pathways have more Cl− partitioned into storage and hence the potential for legacy Cl− effects on aquatic organisms. While we did measure statistically significant increasing trends in stream Cl− concentration in some watersheds, there was no consistent relationship between the long-term rate of change in stream Cl− concentrations and patterns of urbanization and the magnitude of Cl− retention. Based on our results we present a detailed conceptual model of watershed Cl− dynamics that can be used to guide future research into the mechanisms of Cl− retention and release within a watershed.

The long-term rate of change in lung function in urban professional firefighters: a systematic review

BackgroundDespite the known occupational hazards, it is not yet clear whether long-term career firefighting leads to a greater rate of decline in lung function than would normally be expected, and how this rate of change is affected by firefighting exposures and other risk/protective factors.MethodsA systematic search of online electronic databases was conducted to identify longitudinal studies reporting on the rate of change in the forced expiratory volume in one second (FEV1) of forced vital capacity (FVC). Included studies were critically appraised to determine their risk of bias using the Research Triangle Institute Item Bank (RTI-IB) on Risk of Bias and Precision of Observational Studies.ResultsTwenty-two studies were identified for inclusion, from four different countries, published between 1974 and 2016. Examined separately, studies were categorised by the type of firefighting exposure. Firefighters experienced variable rates of decline in lung function, which were particularly influenced by cigarette smoking. The influence of routine firefighting exposures is unclear and limited by the methods of measurement, while firefighters exposed to ‘non-routine’ severe exposures unanimously experienced accelerated declines.ConclusionsThe data provided by longitudinal studies provide an unclear picture of how the rate of change in lung function of firefighters relates to routine exposures and how it compares to the rate of change expected in a working-age population. Non-smoking firefighters who routinely wear respiratory protection are more likely than otherwise to have a normal rate of decline in lung function. Exposure to catastrophic events significantly increases the rate of decline in firefighter lung function but there is limited evidence detailing the effect of routine firefighting. Future studies will benefit from more robust methods of measuring exposure.Trial registrationInternational Prospective Register of Systematic Reviews (PROSPERO), registration number (CRD42017058499).

Platelet-related biomarkers and their response to inhibition with aspirin and p2y12-receptor antagonists in patients with acute coronary syndrome.

The PLATelet inhibition and patient Outcomes (PLATO) trial showed that treatment with ticagrelor reduced the rate of death due to vascular causes, myocardial infarction and stroke when compared to clopidogrel in patients with ST-elevation or non-ST-elevation acute coronary syndrome (ACS). While the comparative benefit of ticagrelor over clopidogrel increased over time, event rates accrued in both groups during the study period. The purpose of our biomarker-based exploratory analysis was to determine whether long-term platelet inhibition may be associated with platelet adaptation. A sample of 4000 participants from the PLATO trial also consented to participate in a prospectively designed biomarker substudy. Blood samples were procured at baseline, immediately prior to hospital discharge and at 1 and 6months. Markers of platelet activity, including platelet count, serum CD40-ligand and soluble P-selectin were analyzed. Mean levels were compared at discharge, 1 and 6months following study drug initiation-first for all patients and subsequently stratified by treatment group. A linear mixed model was used to estimate the short-term change rate (baseline to 1month) and long-term change rate (1-6months) for each biomarker. A Cox proportional hazards model was used to calculate hazard ratios for each change in biomarker over the two time periods examined: baseline to 1month and 1 to 6months. Prior to randomized treatment (baseline), sCD40 ligand and sP-selectin levels were elevated above the normal range of the assay (0.39 and 33.5µg/L, respectively). The mean level of each biomarker was significantly different at 1month compared to baseline (p < 0.0001). When stratified by treatment group, at 1month patients treated with ticagrelor had a larger increase in platelet count compared to those treated with clopidogrel (p < 0.0001). Similarly, when comparing biomarker levels for all patients at 6months with those at 1month, each differed significantly (p < 0.05). There was no significant difference between treatment groups during this time period. The rate of change for both platelet count and sP-selectin were significantly different between baseline and 1month when compared to the 1 to 6-month time period (p < 0.0001). When comparing treatment groups, the rate of increase in platelets from baseline to 1month was greater for patients treated with ticagrelor (p < 0.0001). This was no longer observed in the 1 to 6-month interval. Using a Cox proportional hazard model, the increase in platelet count from 1 to 6months was associated with ischemic-thrombotic events, while sCD40 ligand decrease from 1 to 6months was associated with hemorrhagic events. There were no differences between treatment groups for the associations with clinical endpoints. Dynamic changes in platelet count, sCD-40 ligand and sP-selectin occur over time among patients with ACS. Platelet-directed therapy with a P2Y12 receptor inhibitor in combination with aspirin modestly impacts the expression of these biomarkers. Platelet count and sCD40 ligand may offer modest overall predictive value for future ischemic-thrombotic or hemorrhagic clinical events, respectively. The existence of a platelet adaptome and its overall clinical significance among patients at risk for thrombotic events will require a more in-depth and platelet-biology specific investigation.

Neighborhood Predictors of Cognitive Training Outcomes and Trajectories in ACTIVE.

We examined the influence of neighborhood socioeconomic position (SEP), racial/ethnic composition, and living in a major city on cognitive trajectories and intervention outcomes. Data came from the Advanced Cognitive Training for Independent and Vital Elderly study ( N = 2,438). Mixed effects analyses examined the associations between neighborhood variables and memory, reasoning, speed of processing, and everyday cognition, estimating differences in initial gains (potentially related to practice) and long-term rate of change over 10 years. The effect of reasoning training on initial gain was weaker for individuals in a major city. For everyday cognition, there was a stronger initial gain for memory-trained and control participants in areas with more racial/ethnic minorities and for speed-trained and control individuals in higher SEP areas. The racial/ethnic minority effect was no longer significant after adjustment for multiple comparisons. Neighborhood factors may be more important in practice-related improvement than in long-term change.

Sources of variability in tissue chemistry in northern hardwood species

Measurements of tree tissue chemistry are influenced by the precision and accuracy of laboratory analyses, sampling position within the tree, variation among replicate trees of the same species, and variation from year to year. We characterized these sources of uncertainty for six northern hardwood species and compared them with observed rates of long-term change. Uncertainty associated with laboratory quality control was small (1%–5%) and differed among elements, with K concentrations exhibiting the lowest accuracy and precision. Sampling position within the tree was more important for branches (the coefficient of variation was 23%) and wood (37%) than for foliage or bark (12% for both) (p &lt; 0.001). Foliar N and P concentrations in leaves were less variable than other elements or tissue types both from tree to tree (p = 0.02) and from year to year (p = 0.03), which means that more samples would be needed to detect differences over space or time for Ca, Mg, or K in branches or wood. Concentrations of foliar N increased over 25 years at the Huntington Forest (p ≤ 0.03) by &gt; 16%. Uncertainty analysis can be used to guide the allocation of sampling effort, depending on the elements and tissue types of interest and the objectives of the study.

Abstract 16325: Short-Term Changes in Carotid Artery Inflammation Measured by Positron Emission Tomography are Associated With Long Term Atherosclerosis Progression Measured by Magnetic Resonance Imaging

Introduction: It is unknown whether short-term changes arterial wall inflammation are associated with changes in the rate of structural progression of atherosclerosis. Hypothesis: We assessed arterial inflammation, using positron emission tomography (PET) imaging and 18F-fluorodeoxyglucose (FDG) to test the hypothesis that short term changes in arterial inflammation predict long term atherosclerosis progression, measured by magnetic resonance imaging( MRI). Methods: Forty-two participants enrolled in the dal-PLAQUE study , who underwent both PET and MRI imaging of the carotid arteries were evaluated. Short-term change in arterial inflammation was measured as change in the carotid FDG target to background ratio [TBR] by PET between baseline and 6 months. The long-term rate of atherosclerotic plaque progression was assessed using MRI, as percent change in carotid mean wall area [MWA] and mean wall thickness [MWT] between baseline and 24 months. Results: The mean age of the population was 62.5 years, and 12 (28.6 %) were male. In participants with (vs. without) any increase in arterial inflammation over 6 months, long-term rate of change in MWT was significantly higher (% change MWT: 17.49% vs. 1.74%, p=0.038) and long-term rate of change in MWA was significantly higher (% change MWA: 25.50% vs. 3.59%, p = 0.027). Results remained significant after adjusting for clinical and biochemical covariates. Individuals with no increase in arterial inflammation over 6 months had no significant structural progression of atherosclerosis over 24 months, measured as MWT (p=0.616) or MWA (p=0.373). Conclusions: Short-term changes in arterial inflammation predict long-term atherosclerosis progression. In those with no increase in arterial inflammation, no significant changes in atherosclerosis progression were observed.

Term spread regressions of the rational expectations hypothesis of the term structure allowing for risk premium effects

AbstractThis paper suggests a new empirical methodology of testing the predictions of the term spread between long and short-term interest rates about future changes of the former allowing for term premium effects, according to the rational expectations hypothesis of the term structure. To capture the effects of a time-varying term premium on the term spread, the paper relies on an empirically attractive affine Gaussian dynamic term structure model which assumes that the term structure of interest rates is spanned by three unobserved state variables. To retrieve accurate values of these variables from interest rates series, the paper suggests a new method which can overcome the effects of measurement (or pricing) errors inherent in these series on the estimates of the model. This method is assessed by a Monte Carlo study. Ignoring these errors will lead to biased estimates of term structure models. The empirical results of the paper provide support for the suggested term structure model. They show that this model can efficiently capture the time-varying term premium effects embodied in long-term interest rates, which can explain the failures of term spread to forecast future changes in long-term rates.

Assessment of Surface Runoff Vulnerability to Climate Change in the Lerma-Chapala Basin, Mexico

AbstractThe Intergovernmental Panel on Climate Change (IPCC) suggests that vulnerability to climate change depends on three main factors: exposure, sensitivity, and adaptive capacity. Each factor was evaluated in a hydrologic context; for instance, exposure was interpreted as a change in surface runoff. Factors were combined using a geographic information system (GIS), and an overall methodology was proposed to map hydrologic vulnerability. The Lerma-Chapala basin was selected as a case study since the largest water body in Mexico is located at its outlet. The long-term rate of change in surface runoff was estimated considering the variation in future precipitation from 23 atmosphere–ocean general circulation models (AOGCMs) and by using the reliability ensemble averaging (REA) method. Two climate change scenarios from an IPCC special report on emissions scenarios and three time horizons (2030, 2050, and 2100) were chosen. Results showed a decrease in surface runoff of up to 29% (A1B-2100) in the northern...

Downscaling technique to estimate hydrologic vulnerability to climate change: an application to the Conchos River Basin, Mexico

The Intergovernmental Panel on Climate Change (IPCC) suggests that vulnerability to climate change depends on three main factors: exposure, sensitivity and adaptive capacity. Each factor was evaluated in a hydrologic context, for instance exposure was interpreted as a change in surface runoff. Factors were combined using a Geographic Information System (GIS) and an overall methodology to map hydrologic vulnerability was proposed. The Conchos River Basin, which is the main tributary of the Rio Grande, was used as a case study. The long-term rate of change in surface runoff was estimated considering the variation in future precipitation from 23 Atmosphere-Ocean General Circulation Models (AOGCM) by using the Reliability Ensemble Averaging (REA) method. Two climate change scenarios (A1B and A2) and three time horizons (2030, 2050 and 2100) were chosen. Results showed a decrease in surface runoff up to 28% (A1B-2100) north of the Basin. Hence, it is likely to have more frequent droughts. However, it would be challenging to compensate the lack of surface runoff since groundwater resources are already depleted. Finally, overall hydrologic vulnerability maps were obtained to locate the most vulnerable regions, where precisely adaption efforts would be more necessary to sustain environmental conditions.

Long-Term Rate of Change in Memory Functioning Before and After Stroke Onset

Memory impairment is a predictor and a consequence of stroke, but memory decline is common even in healthy elderly individuals. We compared the long-term trajectory of memory functioning before and after stroke with memory change in stroke-free elderly individuals. Health and Retirement Study participants aged 50 years and older (n=17 340) with no stroke history at baseline were interviewed biennially up to 10 years for first self-reported or proxy-reported stroke (n=1574). Age-, sex-, and race-adjusted segmented linear regression models were used to compare annual rates of change in a composite memory score before and after stroke among 3 groups: 1189 stroke survivors; 385 stroke decedents; and 15 766 cohort members who remained stroke-free. Before stroke onset, individuals who later survived stroke had significantly (P<0.001) faster average annual rates of memory decline (-0.143 points per year) than those who remained stroke-free throughout follow-up (-0.101 points per year). Stroke decedents had even faster prestroke memory decline (-0.212 points per year). At stroke onset, memory declined an average of -0.369 points among stroke survivors, comparable with 3.7 years of age-related decline in stroke-free cohort members. After stroke, memory in stroke survivors continued to decline at -0.142 points per year, similar to their prestroke rates (P=0.93). Approximately 50% of the memory difference between stroke survivors soon after stroke and age-matched stroke-free individuals was attributable to prestroke memory. Although stroke onset induced large decrements in memory, memory differences were apparent years before stroke. Memory declines before stroke, especially among those who did not survive the stroke, were faster than declines among stroke-free adults.

An Extreme Value Approach to Estimating Interest-Rate Volatility: Pricing Implications for Interest-Rate Options

This paper proposes an extreme value approach to estimating interest-rate volatility, and shows that during the extreme movements of the U.S. Treasury market the volatility of interest-rate changes is underestimated by the standard approach that uses the thin-tailed normal distribution. The empirical results indicate that (1) the volatility of maximal and minimal changes in interest rates declines as time-to-maturity rises, yielding a downward-sloping volatility curve for the extremes; (2) the minimal changes are more volatile than the maximal changes for all data sets and for all asymptotic distributions used; (3) the minimal changes in Treasury yields have fatter tails than the maximal changes; and (4) for both the maxima and minima, the extreme changes in short-term rates have thicker tails than the extreme changes in long-term rates. This paper extends the standard option-pricing models with lognormal forward rates to accommodate significant kurtosis observed in the interest-rate data. This paper introduces a closed-form option-pricing model based on the generalized extreme value distribution that successfully removes the well-known pricing bias of the lognormal distribution.

Scale sensitivity of synthetic long-term vegetation time series derived through overlay of short-term field records

Abstract Questions: Is change in cover of dominant species driving the velocity of succession or is it species turnover (1)? Is the length of the time-step chosen in sampling affecting our recognition of the long-term rate of change (2)? Location: 74 permanent plots located in the Swiss National Park, SE Switzerland, ca. 1900 m a.s.l. Methods: We superimpose several time-series from permanent plots to one single series solely based on compositional dissimilarity. As shown earlier (Wildi & Schutz 2000) this results in a synthetic series covering about 400 to 650 yr length. Continuous power transformation of cover-percentage scores is used to test if the dominance or the presence-absence of species is governing secondary succession from pasture to forest. The effect of time step length is tested by sub-samples of the time series. Results: Altering the weight of presence-absence versus dominance of species affects the emerging time frame, while altering time step length is uncritical. Where species turnover ...

Power-Law Neuronal Fluctuations in a Recurrent Network Model of Parametric Working Memory

In a working memory system, persistent activity maintains information in the absence of external stimulation, therefore the time scale and structure of correlated neural fluctuations reflect the intrinsic microcircuit dynamics rather than direct responses to sensory inputs. Here we show that a parametric working memory model capable of graded persistent activity is characterized by arbitrarily long correlation times, with Fano factors and power spectra of neural activity described by the power laws of a random walk. Collective drifts of the mnemonic firing pattern induce long-term noise correlations between pairs of cells, with the sign (positive or negative) and amplitude proportional to the product of the gradients of their tuning curves. None of the power-law behavior was observed in a variant of the model endowed with discrete bistable neural groups, where noise fluctuations were unable to cause long-term changes in rate. Therefore such behavior can serve as a probe for a quasi-continuous attractor. We propose that the unusual correlated fluctuations have important implications for neural coding in parametric working memory circuits.

The Information Content of the Term Structure: An Application to French Government Bonds (in French)

This paper evaluates the information content of the term structure about future changes in interest rates and changes in inflation rate, in France. A data set has been constructed, which contains zero-coupon yield curves on government bonds over the period 1980-95. The information content is generally very weak over the whole period. On the contrary, over the period 1985-95, the term structure contains information for certain maturities. On the one hand, spreads vis-a-vis 2-year rates are informative for future changes in short-term rates, whereas spreads vis-a-vis 3-year rates are informative for both future changes in short-term rates and future changes in long-term rates; on the second hand, the spreads from (2- versus 1-year rates) to (5- versus 1-year rates) and (4- versus 2-year rates) are the most informative for future changes in inflation rate.

A Longitudinal Study of Lung Function in Non-asthmatic Workers in an Aluminum Smelter.

This paper reports a longitudinal study carried out between 1977 and 1989 to determine whether the long-term rate of change in the forced expiratory volume in 1 second (FEV&inf1;) is influenced by exposure to the potroom environment of an aluminum smelter. Workers with diagnosed asthma were excluded from the analysis. The study population consisted of 393 potroom workers, with rate of change in FEV&inf1; used to assess any impairment in airway function. Post-shift urinary fluoride levels and length of service were used to measure exposure. After allowing for age, smoking behavior, and a standardized measure of FEV&inf1;, the rate of change in FEV&inf1; was found to be significantly greater for those workers who had worked shorter times in the potroom. Possible explanations for this finding include unrecognized asthma, a healthy-worker effect, and an exposure effect that occurs early in a worker's experience in the potroom; these explanations are not necessarily mutually exclusive. Apart from the risk of occupational asthma, there does not appear to be any long-term effect on the rate of decline in FEV&inf1; associated with exposure to the potroom environment in workers who remain at work longer than 40 months.