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​According to Mayr, polar organic synthesis can be rationalized by a simple empirical relationship linking bimolecular rate constants to as few as three reactivity parameters. Here, we propose an extension to Mayr’s reactivity method that is rooted in uncertainty quantification and transforms the reactivity parameters into probability distributions. Through uncertainty propagation, these distributions can be transformed into uncertainty estimates for bimolecular rate constants. Chemists can exploit these virtual error bars to enhance synthesis planning and to decrease the ambiguity of conclusions drawn from experimental data. We demonstrate the above at the example of the reference data set released by Mayr and co-workers [J. Am. Chem. Soc. 2001, 123, 9500; J. Am. Chem. Soc. 2012, 134, 13902]. As by-product of the new approach, we obtain revised reactivity parameters for 36 π-nucleophiles and 32 benzhydrylium ions.

We re‐examine the theoretical and empirical relationship between income inequality and long‐run economic growth in an endogenous growth model with a flat tax on income, distributive conflicts among agents, and median voter dynamics. We show that when government spends tax revenue on the provision of public goods in the form of both production and consumption services, the theoretical relationship between inequality and economic growth is neither strictly positive nor strictly negative, but ambiguous. An empirical evaluation of the theoretical findings is carried out by applying a semi‐parametric model on a sample of 63 countries for the period 1991–2017. Results show that the relationship between income inequality and growth takes the form of an inverted U‐shape in that income inequality initially has a positive impact on growth up to an average Gini coefficient threshold of 35.92, beyond which it negatively impacts on growth.

This paper examines the empirical relationship between trade agreements and domestic labour mobility. The domestic‐commitment motive from Maggi and Rodriguez‐Clare (American Economic Review, 97, 2007, 1374) and standard trade models with labour frictions predict that trade liberalisation should occur when labour is more mobile. I find support for this prediction. Using regional trade agreements (RTAs) covering 56 countries in 2015, I show labour mobility is a strong predictor of trade liberalisation. The probability of an RTA increases when the country pair's average domestic labour market is less rigid. When the average labour mobility increases by 1 standard deviation from the mean, the probability of an RTA increases by 14–26%. These results are also consistent with the bound tariffs negotiated under the World Trade Organization, where less rigid labour markets are associated with lower bound tariffs.

A critical porosity model establishes the empirical relationship between a grain matrix and a dry rock by the concept of critical porosity. The model is simple and practical and widely used. But the critical porosity in the model is a fixed value that cannot relate to pore structure. The aim of this paper is to establish the theoretical relationship between critical porosity and pore structure by combining Kuster–Toksoz theory with the critical porosity model. Different from the traditional critical porosity model, critical porosity is not an empirical value but varied with pore shape and the ratio of bulk modulus versus shear modulus of the grain matrix. The substitution of the theoretical relationship into Kuster–Toksoz theory will generate the formulae for the bulk and shear moduli of multiple‐porosity dry rocks, which is named the multiple‐porosity variable critical porosity model. The new model has been used to predict elastic moduli for sandstone and carbonate rock. We compare the modelling results for P‐ and S‐wave velocities and elastic moduli with the experimental data. The comparison shows that the new model can be used to describe the elastic properties for the rocks with multiple pore types.

While the literature is extensive on school districts' revenue sources, less research has been done on the impact of donations on school district funds. In this paper, we extend the theoretical literature on crowding out of private donations by government grants for one type of nonprofit firm, namely charter schools. The theoretical model leads us to focus on the key relationships among fundraising effort, enrollment (which is tied to federal and state funding) and donations. Using a dataset on Texas charter schools we adopt a two‐stage approach to examine the empirical relationship between changes in nondonor revenues and the donations received by charter schools. Like the extensive empirical estimates of the effects of government grants on donations for other types of nonprofit firms, we find evidence of crowding‐out with respect to our sample of charter schools. We also find a significant, positive effect of fundraising on donations with a $1 increase in fundraising associated to a $0.58 increase in donations, a pattern consistent with overinvestment in fundraising. Enrollments exhibit a robust inverse relationship to changes in nondonor revenues. (JEL H00, H32, H50)

This work presents a new approach to defining drought, establishing an empirical relationship between historical droughts (and wet spells) documented in impact reports, and a broad range of observe...

We study the real long‐run effects of the structural stance of monetary policy and of inflation, in the context of a monetary growth model where R&D is complemented with physical capital accumulation. We look into the effects on a set of real macroeconomic variables that have been of interest to policymakers—the economic growth rate, real interest rate, physical investment rate, capital‐to‐labor ratio, R&D intensity, and velocity of money. These variables have been previously analyzed from the perspective of different, separated, strands of the theoretical and empirical literature. Additionally, we analyze the long‐run relationship between inflation and both the effectiveness of real industrial‐policy shocks and the market structure, assessed namely by average firm size. We present novel cross‐country evidence on the empirical relationship between the latter and long‐run inflation.

Recent published evidence indicates a negative correlation between density of populations and the distance of their environments to a suitably defined ‘niche centroid’. This empirical observation lacks theoretical grounds. We provide a theoretical underpinning for the empirical relationship between population density and position in niche space, and use this framework to understand the circumstances under which the relationship will fail. We propose a metapopulation model for the area of distribution, as a system of ordinary differential equations coupled with a dispersal kernel. We present an analytical approximation to the solution of the system as well as R code to solve the full model numerically. We use this tool to analyze various scenarios and assumptions. General and realistic demographic assumptions imply a good correlation between position in niche space and population abundance. Factors that modify this correlation are: transitory states, a heterogeneous spatial structure of suitability, and Allee effects. We also explain why the raw output of the niche modeling algorithm MaxEnt is not a good predictor of environmental suitability. Our results elucidate the empirical results for spatial patterns of population size in niche terms, and provide a theoretical basis for a structured theory of the niche.

This paper considers whether a fairly well-established empirical relationship between liberalized trade and firm productivity growth is sensitive to the choice of an identification strategy for production function estimation. We estimate the productivity of Colombian manufacturing plants using the methods of Levinsohn and Petrin (2003), Ackerberg, Caves, and Frazer (2006), and Gandhi, Navarro, and Rivers (2012), and at times come to surprisingly different conclusions about the country's experience with trade policy reform during the 1980s. Results from a quantile regression model and a productivity growth decomposition exercise tend to vary as we experiment with different specifications of the production function. Research that is concerned with the short and medium-term impact of trade liberalization on domestic manufacturing industries should therefore pay close attention to issues of robustness to alternative strategies for estimating the productivity of firms.

We investigate the empirical relationship between macroeconomic risk, bank liquidity, and bank risk surrounding the 1999 Financial Services Modernization Act. We propose that bank risk and liquidity are positively related as macroeconomic risk increases, and that this effect is particularly strong after the Gramm–Leach–Bliley Act (GLBA). We test our hypotheses by collecting data from 1994 to 2006 for banks in the United States. The results show that banks flush with liquid assets in a high macroeconomic risk environment conducted more lending activities following the enactment of the GLBA, leading to higher bank risk. Our study complements the understanding of bank liquidity management.

The empirical relationship between economic diversity and economic stability varies when it is measured at different geographical scales. This paper evaluates the role of geographical scales in assessing this diversity-stability relationship among counties, states, Economic Areas (EAs), metropolitan counties and metropolitan statistical areas (MSAs) in the contiguous U.S. When choosing geographical units to analyze regional economic structure, it is necessary that the geographical units be large enough in population and employment to quantify effectively the regional economic structure. In addition, this paper proposes that geographical units also should be functionally aggregated regions as they better represent spatial interactions than formal regions do, and they consider the possible temporal variations in the boundaries of regional economic structures.

Forecasting distribution shifts under novel environmental conditions is a major task for ecologists and conservationists. Researchers forecast distribution shifts using several tools including: predicting from an empirical relationship between a summary of distribution (population centroid) and annual time series (“annual regression,” AR); or fitting a habitat‐envelope model to historical distribution and forecasting given predictions of future environmental conditions (“habitat envelope,” HE). However, surprisingly little research has estimated forecast skill by fitting to historical data, forecasting distribution shifts and comparing forecasts with subsequent observations of distribution shifts. I demonstrate the important role of retrospective skill testing by forecasting poleward movement over 1‐, 2‐ or 3‐year periods for 20 fish and crab species in the Eastern Bering Sea and comparing forecasts with observed shifts. I specifically introduce an alternative vector‐autoregressive spatio‐temporal (VAST) forecasting model, which can include species temperature responses, and compare skill for AR, HE and VAST forecasts. Results show that the HE forecast has 30%–43% greater variance than predicting that future distribution is identical to the estimated distribution in the final year (a “persistence” forecast). Meanwhile, the AR explains 2%–6% and VAST explains 8%–25% of variance in poleward movement, and both have better performance than a persistence forecast. HE and AR both generate forecast intervals that are too narrow, while VAST models with or without temperature have appropriate width for forecast intervals. Retrospective skill testing for more regions and taxa should be used as a test bed to guide future improvements in methods for forecasting distribution shifts.

[The BQART formulais an empirical relationship between observed total suspend sediment load (Tss) and catchment area (A), relief (R), temperature (T), water discharge (Q) and erodibility (B) in modern river systems. Application of the method for anancient S2S mass budget study requires: (1) an assessment of the methods suitability, (2) a paleogeographicreconstruction, (3) a paleoclimate reconstruction and (4) Monte Carlo simulations. , Abstract Constraining the timing and volume of sediment dispersal in an ancient sedimentary system is vital to understand a basin's infill history. One preferred method for a first‐order approximation of ancient sediment load estimates, the BQART model, is based on empirical observations of modern river systems relating basin morphology, topography, climate, run‐off and bedrock characteristics. Despite the popularity of such methods, a comprehensive assessment on the validity of using modern river observations to measure sediment load on geological timescales is lacking. Here, we investigate the uncertainties, sensitivities and practicalities surrounding the use of modern empirical observations in general and the BQART model in particular, to evaluate ancient sediment river loads. Although catchment area and relief are the least constrained parameters in an ancient sedimentary system, the temperature parameter may have an even more significant impact in the range of predicted sediment load estimates using a BQART approach. The applicability of BQART is most suitable for regional to continental scale source‐to‐sink systems that are based on robust paleogeographic and paleoclimatic models of cold ( 8°C) climates. One further needs to consider the high amplitude discharge events that can dominate the stratigraphic record which are not captured by historical observations of sediment load over a 30‐year period. In addition, our limited understanding of bedload material transport and an unknown pristine environment in the Anthropocene reduce the reliability of modern sediment load estimates for the ancient. Mass budget estimates in deep time based on empirical relationships of modern river systems can thus provide first‐order estimates within an order of magnitude but need to consider the limitations imposed by extrapolating the modern to the ancient. Here, we present a framework to consider the suitability of the BQART method for ancient source‐to‐sink mass budget analyses.]

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link. We use the Least Absolute Shrinkage and Selection Operator (LASSO) quantile regression technique to construct and analyse the complete tail risk connectedness network of the whole US industry system. We also investigate the empirical relationship between input-output linkages and the tail risk spillovers among US industries. Our findings identify the tail-risk drivers, tail-risk receivers, and tail-risk distributors among industries and confirm that the actual trade flow between industries is a major driver of their tail risk connectedness.

We assess the time‐varying features of fiscal sustainability in the euro area via revisiting the empirical relationship between the primary budget surplus and the debt‐to‐GDP ratio. Focusing on a sample of 11 Euro‐area countries between 1999Q1 and 2013Q4 and by means of time series analyses, we find that (a) fiscal policy seems to have been sustainable in Belgium, France, Germany, and the Netherlands and a Ricardian (monetary dominant) regime might have been present; (b) debt exhibited a negative response following an innovation in the budget surplus in half of the sample; (c) the time‐varying coefficient model shows that the 2008– 2009 global economic and financial crisis exerted a sizeable negative impact on fiscal sustainability; and (d) expenditure‐based fiscal rules are strong determinants of fiscal sustainability. All in all, we found some evidence against the Fiscal Theory of the Price Level. info:eu-repo/semantics/publishedVersion

Countries with different levels of state capacity have access to different sets of policies. In particular, countries with strong state capabilities are able to draw from a broader menu of policies than countries with lower capabilities. We apply and test this insight to the case of exposure to trade-related risk. So far, most of the literature has considered that only one type of policy—the one that increases government size—can help to overcome the challenge imposed by openness. However, there are a number of policies that can mitigate trade-induced risks, many of which do not have the necessary implication of increasing public spending. Yet, many such policies require governmental capabilities not available to any country. For that reason, while the choice of a particular policy within a menu depends on political conditions, the relationship between openness and the size of government might be mediated by the capabilities of states. This paper provides reduced form evidence confirming that the empirical relationship between openness and government size is conditional on state capabilities. Therefore, public policies cannot be assessed independently of the capacity of the State that would have to implement them.

Modern coexistence theory and contemporary niche theory represent parallel frameworks for understanding the niche's role in species coexistence. Despite increasing prominence and shared goals, their compatibility and complementarity have received little attention. This paucity of overlap not only presents an obstacle to newcomers to the field, but it also precludes further conceptual advances at their interface. Here, we present a synthetic treatment of the two frameworks. We review their main concepts and explore their theoretical and empirical relationship, focusing on how the resource supply ratio, impact niche, and requirement niche of contemporary niche theory translate into the stabilizing and equalizing processes of modern coexistence theory. We show, for a general consumer–resource model, that varying resource supply ratios reflects an equalizing process; varying impact niche overlap reflects a stabilizing process; and varying requirement niche overlap may be both stabilizing and equalizing, but has no qualitative effect on coexistence. These generalizations provide mechanistic insight into modern coexistence theory, while also clarifying the role of contemporary niche theory's impacts and requirements in mediating coexistence. From an empirical perspective, we recommend a hierarchical approach, in which quantification of the strength of stabilizing mechanisms is used to guide more focused investigation into the underlying niche factors determining species coexistence. Future research that considers alternative assumptions, including different forms of species interaction, spatiotemporal heterogeneity, and priority effects, would facilitate a more complete synthesis of the two frameworks.

Gas transfer velocities (k) of CO2 and CH4 were determined from 209 deployments of a newly designed floating chamber in six mangrove dominated estuaries in Australia and the United States to estimate mangrove system specific k. k600-CO2 and k600-CH4 (k normalized to the Schmidt number of 600) varied greatly within and between mangrove creeks, ranging from 0.9 cm h−1 to 28.3 cm h−1. The gas transfer velocity correlated well with current velocity at all study sites suggesting current generated turbulence was the main driver controlling k. An empirical relationship that accounts for current velocity and a linearly additive contribution of wind speed and water depth was a good predictor of k600-CO2 (R2 = 0.67) and k600-CH4 (R2 = 0.57) in the mangrove creeks in Australia. In a side-by-side study, good agreement was found between k determined from this new floating chamber and a 3He/SF6 dual tracer release experiment (∼5% discrepancy). k600-CH4 correlated well with k600-CO2 (R2 = 0.81), however, k600-CH4 was on average 1.2 times higher than k600-CO2, most likely reflecting a microbubble flux contribution. The microbubble flux contributed up to 73% of the total CH4 flux and was best predicted by a model that included CH4 supersaturation, temperature, and current velocity. A large overestimation was found for both CO2 and CH4 fluxes when calculated using empirically derived k models from previous studies in estuaries. The high temporal and spatial variabilities of kCO2 and kCH4 highlights the importance of site specific transfer velocity measurements in dynamic ecosystems such as mangrove estuaries.

The first part of this investigation was aimed at testing the use of a three-dimensional (3D) Digital Terrain Model (DTM) and a quasi-tridimensional (2.5D) Digital Elevation Model (DEM) obtained by a large series of oblique images of eroded channels taken from consumer un-calibrated and non-metric cameras. For two closed earth channels having a different sinuosity the ground measurement of some cross-sections by a profilometer (P) was carried out. The real volume of each channel was also measured by waterproofing it by a plastic film and filling it with a known volume of water. The comparison among the three methods (3D, 2.5D and P) pointed out that a limited underestimation of the total volume always occurs and that the 3D method is characterized by the minimum difference between measured and real volume.This preliminary analysis allowed to conclude that 3D model can be used as benchmark and the 2.5D model is accurate enough to describe the investigated earth channels. In the subsequent part of the investigation the three ground measurement methods were applied for surveying of an ephemeral gully (EG) channel at the Sparacia area. Using the 3D model as benchmark, the morphological and hydraulic variable values of the 24 surveyed cross-sections determined by both 2.5D model and profilometer were compared. This comparison showed that the estimate error is generally less than ±10%. The EG measurements carried out by the three methods agreed with the available literature measurements and supported the applicability both of the empirical relationship between EG length and its eroded volume and the theoretical dimensionless relationship among the morphological variables describing the channelized erosion process. Finally, it was demonstrated that the effect of the distance interval on the EG volume measurement by 3D and 2.5D models is negligible for the investigated EG.

Research summary: We revisit the empirical relationship between multinationality and performance by attempting to replicate the widely cited S-shape relationship reported in Lu and Beamish (2004). Using a longitudinal and comprehensive database on the population of U.S. MNCs from 1989 to 2007, we find no evidence of an S-shaped relationship; nor do we see a moderating effect of intangible assets. Although our results do show a marginally significant U-shaped association between multinationality and performance for a subsample of manufacturing firms, this relationship disappears once we account for the endogeneity of multinationality. Our study contributes to empirical research on the multinationality-performance relationship, highlighting the need for caution in generalizing results across countries and the importance of controlling for the endogeneity of multinationality when assessing its effect on performance. Managerial summary: Our study examines the relationship between a firm's multinationality and its performance. In a much-cited study, Lu and Beamish (2004) found evidence of an S-shaped relationship-with firm performance first decreasing, then increasing, then decreasing again as firms internationalized-in a sample of Japanese firms from 1986 to 1997. We test for the same relationship across all U.S. MNCs from 1989 to 2007, and find no evidence of an S-shaped pattern, or indeed, of any effect of multinationality at an aggregate level. Our study thus suggests that the effect of multinationality may vary with firm capabilities and home country environments, and that managers and academics alike should focus on understanding these specifics, rather than searching for a universal effect of multinationality on performance. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This paper presents new evidence on the empirical relationship between bank solvency and funding costs. Building on a newly constructed data set drawing on the supervisory data of 54 large banks from six advanced countries over 2004–2013, we use a simultaneous equation approach with panel data to estimate the contemporaneous interaction between solvency and funding costs. Our results and test statistics show that these two are (a) determined simultaneously and (b) more pronounced than suggested by the existing empirical literature. A 100‐bps increase in regulatory capital ratios is associated with a decrease of bank funding costs of about 113 bps. A 100‐bps increase in funding costs reduces regulatory capital buffers by 48 bps. Applying our estimation results to the 2014 EU‐wide stress test reveals that neglecting the solvency‐funding cost nexus leads to the systematical and significant underestimation of the impact of shocks on bank capital ratios.

The size of animal home ranges often varies inversely with population density among populations of a species. This fact has implications for population monitoring using spatially explicit capture–recapture (SECR) models, in which both the scale of home-range movements σ and population density D usually appear as parameters, and both may vary among populations. It will often be appropriate to model a structural relationship between population-specific values of these parameters, rather than to assume independence. We suggest re-parameterizing the SECR model using kp = σp √Dp, where kp relates to the degree of overlap between home ranges and the subscript p distinguishes populations. We observe that kp is often nearly constant for populations spanning a range of densities. This justifies fitting a model in which the separate kp are replaced by the single parameter k and σp is a density-dependent derived parameter. Continuous density-dependent spatial variation in σ may also be modelled, using a scaled non-Euclidean distance between detectors and the locations of animals. We illustrate these methods with data from automatic photography of tigers Panthera tigris across India, in which the variation is among populations, from mist-netting of ovenbirds Seiurus aurocapilla in Maryland, USA, in which the variation is within a single population over time, and from live-trapping of brushtail possums Trichosurus vulpecula in New Zealand, modelling spatial variation within one population. Possible applications and limitations of the methods are discussed. A model in which kp is constant, while density varies, provides a parsimonious null model for SECR. The parameter k of the null model is a concise summary of the empirical relationship between home-range size and density that is useful in comparative studies. We expect deviations from this model, particularly the dependence of kp on covariates, to be biologically interesting.

Various remote-sensing methods are available to estimate soil moisture, but few address the fine spatial resolutions (e.g. 30-m grid cells) and root-zone depth requirements of agricultural and other similar applications. One approach that has been previously proposed to estimate fine-resolution soil moisture is to first estimate the evaporative fraction from an energy balance that is inferred from optical and thermal remote-sensing images [e.g. using the Remote Sensing of Evapotranspiration (ReSET) algorithm] and then estimate soil moisture through an empirical relationship to evaporative fraction. A similar approach has also been proposed to estimate the degree of saturation. The primary objective of this study is to evaluate these methods for estimating soil moisture and degree of saturation, particularly for a semi-arid grassland with relatively dry conditions. Soil moisture was monitored at 28 field locations in south-eastern Colorado with herbaceous vegetation during the summer months of 3 years. In situ soil moisture and degree of saturation observations are compared with estimates calculated from Landsat imagery using the ReSET algorithm. The in situ observations suggest that the empirical relationships with evaporative fraction that have been proposed in previous studies typically provide overestimates of soil moisture and degree of saturation in this region. However, calibrated functions produce estimates with an accuracy that may be adequate for various applications. The estimates produced by this approach are more reliable for degree of saturation than for soil moisture, and the method is more successful at identifying temporal variability than spatial variability in degree of saturation for this region. Copyright © 2015 John Wiley & Sons, Ltd.

Radar-based estimates of rainfall are affected by many sources of uncertainties, which would propagate through the hydrological model when radar rainfall estimates are used as input or initial conditions. An elegant solution to quantify these uncertainties is to model the empirical relationship between radar measurements and rain gauge observations (as the ‘ground reference’). However, most current studies only use a fixed and uniform model to represent the uncertainty of radar rainfall, without consideration of its variation under different synoptic regimes. Wind is such a typical weather factor, as it not only induces error in rain gauge measurements but also causes the raindrops observed by weather radar to drift when they reach the ground. For this reason, as a first attempt, this study introduces the wind field into the uncertainty model and designs the radar rainfall uncertainty model under different wind conditions. We separate the original dataset into three subsamples according to wind speed, which are named as WDI (0–2 m/s), WDII (2–4 m/s) and WDIII (>4 m/s). The multivariate distributed ensemble generator is introduced and established for each subsample. Thirty typical events (10 at each wind range) are selected to explore the behaviours of uncertainty under different wind ranges. In each time step, 500 ensemble members are generated, and the values of 5th to 95th percentile values are used to produce the uncertainty bands. Two basic features of uncertainty bands, namely dispersion and ensemble bias, increase significantly with the growth of wind speed, demonstrating that wind speed plays a considerable role in influencing the behaviour of the uncertainty band. On the basis of these pieces of evidence, we conclude that the radar rainfall uncertainty model established under different wind conditions should be more realistic in representing the radar rainfall uncertainty. This study is only a start in incorporating synoptic regimes into rainfall uncertainty analysis, and a great deal of more effort is still needed to build a realistic and comprehensive uncertainty model for radar rainfall data. Copyright © 2014 John Wiley & Sons, Ltd.

Comparison of the movements in the VIX index, the rand – dollar exchange rate and South African CPI inflation reveals a striking resemblance between them, raising the question as to whether or not there is an empirical relationship among them. The aim of this paper is to determine whether or not changes in market uncertainty, as reflected in the VIX index, influence South African inflation. Given that the VIX index reflects market uncertainty, its impact on the inflation rate may differ between times of heightened uncertainty and normality, thus suggesting the presence of multiple regimes. To cater for this possibility, the analysis first uses the general-to-specific procedure (including squared and cubed values of dependent and independent variables) with impulse indicator saturation dummies to look for non-linear behaviour in the form of statistically significant squared and cubed variables and clustered periods of outlier dummies that might reflect an alternative regime. Finding such periods, the analysis next uses a Markov-switching model to model this non-linear behaviour explicitly. The results show that market volatility as measured by the VIX indeed explains South African inflation. Moreover, as shown by the second regime of the Markov-switching model, when market volatility is elevated, its influence on inflation also increases.

A model of dissolved oxygen (DO) and biological oxygen demand (BOD) was developed to assess the water quality of Panshet and Ujjani Reservoir in Maharashtra, India, to ascertain if their water was suitable for various beneficial and designated uses. The model was calibrated with observed data from these two reservoirs. Seasonal water quality variations were studied during 2010–2011 The pH of Panshet Reservoir water is almost neutral, whereas Ujjani Reservoir is marginally alkaline. A rapid decrease in DO with depth during the summer appeared to be a common phenomenon for both reservoirs. Although the mean phosphate concentrations of both reservoirs were comparable, biological growth was much higher in Ujjani Reservoir, being attributed to a higher dissolved salt concentration in Ujjani Reservoir. The nitrate (NO3−) concentrations in both reservoirs remained within a range close to the global average for unpolluted freshwater. Sewage contamination appears to be a major problem for Ujjani Reservoir, especially as it relates to domestic water uses. A two-layer, two-dimensional mathematical model also was developed to assess reservoir water quality. An explicit, second-order-accuracy finite-volume technique was used to solve two-dimensional shallow water equations. The governing equations were solved with a Mac Cormack predictor–corrector scheme. The Reynolds turbulence terms were modelled with a sub-grid-scale (SGS) model, using a large eddy simulation (LES) approach. An empirical relationship developed by Street and Phelps describing liquid–air phase demand and natural re-aeration was used to determine water quality parameters. The model was validated with numerical results from the literature. The field investigations were satisfactorily applied for the simulation of hydrodynamics and the prediction of DO and BOD in Panshet and Ujjani Reservoir.

This paper documents important changes in the Chinese macroeconomic environ- ment over the last three decades. The volatility of Chinese aggregate economic activities has fallen dramatically by nearly 60 per cent during its reform period, a phenomenon that coincides with the 'Great Moderation' that occurred in most industrialized economies. We employ a provincial panel-data method to investigate the driving forces of the increasing macroeconomic stability in China. We examine the empirical relationship between output volatility and various economic, policy, institutional, and demographic factors. Our results suggest that the accelera- tion of reform toward the market economy, which began around 1994, generally leads to a widespread output volatility reduction across Chinese provinces. Both state-owned enterprise reform and human capital accumulation are important determinants of output volatility since the mid-1990s; they play an important role in explaining the provincial differences on volatility reduction.

The empirical relationship between differences in endowments and different types of trade is investigated in this paper. Although net trade (NT) and vertical intra-industry trade (IIT) are both broadly viewed as reflecting endowment differences, we suggest that there will be systematic differences in the way their shares of trade adjust as endowment differences become larger. Empirical evidence for European Union trade with its 52 major trading partners confirms this. The share of horizontal IIT (net trade) decreases (increases) for all increases in absolute endowment differences, but the share of vertical IIT can both increase and decrease with increases in endowment differences.

A near-complete 4 year data set of 10 min average 80 m wind speeds is used to examine the impact of missing data on monthly and yearly estimates of mean wind speed and energy production from a generic wind turbine. Missing data is a source of uncertainty in wind energy resource assessment studies. Quantifying that uncertainty can improve the reliability of P90 and related wind farm energy production estimates. An empirical relationship between missing data percentage and relative uncertainty in monthly mean wind speed is derived. Relationships between uncertainties in monthly average wind speed and uncertainties in monthly energy production are also explored. In many cases with monthly data losses of 10% or less the contribution to the overall uncertainty in annual energy production will be small (

Ground level vapour (GLV) samples were collected at Roorkee, Uttarakhand, India using two methods: liquid condensation (LC) at 0 °C and cryogenic trap (CT) at −78 °C for the period 2009–2011. The study reveals that there is a considerable fluctuation in stable isotopic composition of GLV throughout the year. The study area receives complex moisture source during different seasons, which is evident from the moisture flux received during different seasons. The isotopic composition of the GLV in both methods shows depleted nature during rainout process. CT method shows exact isotopic signature of GLV because of maximum trapping of air moisture and its condensation, whereas LC method shows depleted or enriched character because of the prevalence of kinetic and diffusive fractionation. The d value shows that LC method acts as magnifier of the CT method and clearly shows seasonal effect than the clustered CT method. Hence, to decipher the original isotopic signature of GLV, isotopic composition of GLVLC can be converted to GLVCT by deriving an empirical relationship with changing season and locations. Meteorological parameters show varied behaviour with GLVCT and LC because of moisture sources in all seasons. The GLVCT and LC method shows significant correlation with meteorological parameters when the region is dominated by single moisture source. The GLVLC method magnifies the correlation with meteorological parameters when the region is influenced by more than one source. The study shows that the GLVLC methods can be used in place of GLVCT when the objective is to understand the influence of different moisture sources on GLV. Copyright © 2012 John Wiley & Sons, Ltd.

SUMMARY In this study, to determine the elastic and inelastic structural responses of mid-rise building frames under the influence of soil–structure interaction, three types of mid-rise moment-resisting building frames, including 5-storey, 10-storey and 15-storey buildings are selected. In addition, three soil types with the shear wave velocities less than 600 m/s, representing soil classes Ce, De and Ee according to AS 1170.4–2007 (Earthquake action in Australia, Australian Standards), having three bedrock depths of 10 m, 20 m and 30 m are adopted. The structural sections are designed after conducting nonlinear time history analysis, on the basis of both elastic method and inelastic procedure considering elastic-perfectly plastic behaviour of structural elements. The frame sections are modelled and analysed, employing finite difference method adopting FLAC2D software under two different boundary conditions: (a) fixed base (no soil–structure interaction) and (b) considering soil–structure interaction. Fully nonlinear dynamic analyses under the influence of different earthquake records are conducted, and the results in terms of the maximum lateral displacements and base shears for the above mentioned boundary conditions for both elastic and inelastic behaviours of the structural models are obtained, compared and discussed. With the results, a comprehensive empirical relationship is proposed to determine the lateral displacements of the mid-rise moment-resisting building frames under earthquake and the influence of soil–structure interaction. Copyright © 2012 John Wiley & Sons, Ltd.

For many citizens and policymakers, the empirical relationship between economic growth and biodiversity conservation has not been sufficiently established for purposes of identifying the types of economic policies amenable to biodiversity conservation. Some think economic growth conflicts with biodiversity conservation; others think economic growth conduces biodiversity conservation. With panel data from 1997-2011, encompassing US continental states, we developed a series of statistical models to investigate the relationships among species endangerment, human population, and economic growth as indicated by GDP and per capita GDP. Species endangerment is highly correlated with population and GDP, and per capita GDP is a significant regressor of species endangerment. Across US continental states, competitive exclusion of non-human species occurs via human economic growth and population growth.

I. INTRODUCTION There is a shared belief among economists, policy makers, and the general public that more open economies grow faster than closed economies. Many international organizations emphasize this correlation: for example, the World Trade Organization proclaims on its website that it has "helped to create a strong and prosperous trading system contributing to unprecedented growth." However, the empirical evidence is mixed. While many studies demonstrate a positive relationship between trade openness and economic growth (Edwards 1998; Frankel and Romer 1999; Sachs and Warner 1995; and many others), others find no evidence of such a relationship. Harrison and Hanson (1999) demonstrate the lack of robustness of several proxies for "openness," for example, while Vamvakidis (2002) finds that the positive correlation between openness and growth exists only after 1970, and Clemens and Williamson (2004) show that the correlation between tariffs and growth was positive prior to World War II and negative after it, which they attribute to changes in the world economy. Perhaps it is not surprising that empirical work has failed to reach a consensus about the correlation between trade protection and growth, because theory does not generally provide an unambiguously negative relationship. In endogenous growth models in open-economy frameworks such as Grossman and Helpman (1990) and Matsuyama (1992), the relationship between trade policy and growth is frequently a contingent one, in which the effect of trade barriers on growth depends on the pattern of comparative advantage across countries. Rodr{guez and Rodrik (2000) expand upon this idea, and also provide a comprehensive and critical review of the empirical literature. As discussed in more detail below, DeJong and Ripoll (2006) allow for contingencies in the correlation between tariffs and growth, based primarily on countries' levels of economic development. Motivated by open-economy endogenous growth models, we examine the relationship between trade protection and growth in a nonlinear framework, and investigate whether the relationship between trade barriers and growth depends on the pattern of comparative advantage across countries. Using a cross-country regression model, we find that such contingencies do in fact exist, and that the correlation between tariffs and growth is strong and positive for skill-abundant countries. Our results are robust to a number of different specifications of conditioning variables and dependent variables. This paper is related to a large literature on openness and growth. As indicated above, many previous empirical studies have assumed a linear relationship between openness and growth. Notable exceptions in which nonlinearities in this relationship are the main focus of the paper are DeJong and Ripoll (2006) and Papageorgiou (2002). (1) In Papageorgiou (2002), trade openness is a threshold variable separating countries into distinct growth regimes; however, openness is not directly included in the growth specification, but operates indirectly, as a separating variable. In contrast, we focus on the potential nonlinearity of the direct relationship between trade barriers and growth, and we find evidence that such nonlinearities do, in fact, exist, in that the relationship between tariffs and growth is contingent on the pattern of comparative advantage across countries. Using a panel of 60 countries, DeJong and Ripoll (2006) investigate the relationship between tariffs and growth and how this relationship depends on income levels. Among higher-income countries, they find a negative correlation between tariffs and growth. Unlike DeJong and Ripoll (2006), we allow for the possibility that the relationship between trade barriers and growth is contingent on the pattern of comparative advantage. Relying on the pattern of comparative advantage, rather than income, as the source of differences in the correlation between growth and tariffs is more consistent with the endogenous growth models, although we do include an interaction between income and tariffs in our sensitivity analysis as a comparison to their paper. …

SUMMARY This paper analyzes how the establishment of the United States Court of Appeals for the Federal Circuit in 1982 has affected the relationship between innovation and competition. Using the same dataset as Aghion et al. (Competition and innovation: an inverted-u relationship. Quarterly Journal of Economics 2005; 120(2):701–728) I find a structural break in the early 1980s. Taking this break into consideration, the inverted-U empirical relationship between innovation and competition found by Aghion et al. does not hold. In fact, I find that there is a positive innovation–competition relationship during the period 1973–1982 and no relationship at all in the 1983–1994 period. Copyright © 2011 John Wiley & Sons, Ltd.

Summary 1. Predation rate (PR) and kill rate are both fundamental statistics for understanding predation. However, relatively little is known about how these statistics relate to one another and how they relate to prey population dynamics. We assess these relationships across three systems where wolf‐ prey dynamics have been observed for 41 years (Isle Royale), 19 years (Banff) and 12 years (Yellowstone). 2. To provide context for this empirical assessment, we developed theoretical predictions of the relationship between kill rate and PR under a broad range of predator‐prey models including predator-dependent, ratio-dependent andLotka-Volterradynamics. 3. The theoretical predictions indicate that kill rate can be related to PR in a variety of diverse ways (e.g. positive, negative, unrelated) that depend on the nature of predator‐prey dynamics (e.g. structure of the functional response). These simulations also suggested that the ratio of predatorto-prey is a good predictor of prey growth rate. That result motivated us to assess the empirical relationship between the ratio andprey growthrate foreachof thethree studysites. 4. The empirical relationships indicate that PR is not well predicted by kill rate, but is better predicted by the ratio of predator-to-prey. Kill rate is also a poor predictor of prey growth rate. However, PR and ratio of predator-to-prey each explained significant portions of variation in prey growthrate fortwoof thethree studysites. 5. Our analyses offer two general insights. First, Isle Royale, Banff and Yellowstone are similar insomuch as they allinclude wolves preyingon largeungulates.However,they also differ in species diversityofpredatorandpreycommunities,exploitationbyhumansandtheroleofdispersal. Even with the benefit of our analysis, it remains difficult to judge whether to be more impressed by the similarities or differences. This difficulty nicely illustrates a fundamental property of ecological communities. Second, kill rate is the primary statistic for many traditional models of predation. However, our work suggests that kill rate and PR are similarly important for understanding why predation is such a complexprocess.

Soil water content measurement using ground-penetrating radar (GPR) requires an appropriate petrophysical relationship between the dielectric permittivity and volumetric water content of the soil. The suitability of different relationships for GPR soil water content estimation has not been thoroughly investigated under natural field conditions for a complete range of seasonal soil conditions. In this study, we examined the ability of various empirical relationships, volumetric mixing formulae, and effective medium approximations to predict near-surface volumetric soil water content using high-frequency direct ground wave (DGW) velocity measurements for three soil textures. The estimated water contents were compared with values obtained from gravimetric sampling. The accuracy of soil water content predictions obtained from the various relationships ranged considerably. The best predictions for the overall data set in terms of RMSE were obtained with a differential effective medium approximation based on a coated sphere model (RMSE = 0.045 m3 m−3); however, an empirical relationship (RMSE = 0.052 m3 m−3) and a volumetric mixing formula (RMSE = 0.048 m3 m−3) also performed well. These best-fitting relationships do exhibit some degree of textural bias that should be considered in the choice of petrophysical relationship for a given data set. Further improvements in water content estimates were obtained using our best-fit third-order polynomial relationship (RMSE = 0.041 m3 m−3) and our three-phase volumetric mixing formula with geometric parameter α = 0.36 (RMSE = 0.042 m3 m−3); these optimized relationships were developed using the DGW permittivity and soil water content data collected in this study.

We conducted a PHABSIM study on Bingham Creek, Washington, by using validated habitat suitability criteria for the rearing of coho salmon Oncorhynchus kisutch. We compared the relationship between weighted usable area (WUA) and flow with a previously determined empirical relationship that showed increasing coho salmon smolt production with increasing summer low flow (). The relationship between juvenile coho salmon WUA and flow indicated that the greatest amount of habitat occurred at a flow that was lower than our low-flow measurement, and the amount of habitat decreased with increasing flow. Thus, PHABSIM results were contrary to empirical measurement of coho salmon smolt production. Based on the relationship between summer flow and smolt production, production of smolts would decline if flow was reduced to the flow that maximizes WUA. The failure of PHABSIM to be consistent with empirical results may have be related to habitat suitability being influenced more by the numerous subdominant, scho...

The complexity of binary maps that is provided by the areal arrangement of colors is considered, and measured using information theory. In addition, information theory provides other measures that have an interpretation in a map context. One of these, redundancy, is examined and found to bear a striking empirical relationship to a spatial autocorrelation statistic. It is argued that spatial autocorrelation is, conceptually as well as empirically, the two-dimensional equivalent of redundancy. It too measures the extent to which the occurrence of an event (color) in an areal unit constrains, or makes more probable, the occurrence of an event in a neighboring areal unit.

What is the relationship between trade and economic growth? Does trade positively affect economic growth? Owing to the ambiguity of this relationship, the empirical relationship has remained open (Rodriguez and Rodrik, 2001; Baldwin, 2003). This paper introduces “trade structure” variables, borrowed from the paper of Lederman and Maloney (2003), and applies them to the relationship. A dynamic panel estimation for the data of 66 countries during 1991–2004 is used to verify the validity and robustness of the relationship. Trade structure variables show strong evidence of positive effects on growth. Free-trade agreements/areas (FTAs) also enhance economic growth. East Asia shows a different relationship between trade and growth than the world and reflects a weaker role of FTAs in its growth.

In this paper an empirical mathematical relationship for concrete’s moisture storage function is proposed. Most of the simple relationships that are used in hygrothermal models for the approximation of building materials’ moisture storage functions cannot provide a very satisfactory estimation for concrete. In this paper, an empirical function, having three branches, is formulated to express concrete’s moisture storage function and to be used in hygrothermal calculations. The formulation of this relationship is analytically presented. The proposed expression can be adjusted to a type of concrete when only the values of free saturation moisture content (relative humidity 100 %) and of moisture content corresponding to 80% air relative humidity are known for this concrete. Vorschlag einer empirischen Beziehung fur die Feuchtespeicherfunktion von Beton. Im vorliegenden Beitrag wird eine empirische mathematische Beziehung fur die Feuchtespeicherfunktion von Beton vorgeschlagen. Die meisten der einfachen Beziehungen, die in hygrothermischen Modellen zur Approximation der Feuchtespeicherfunktionen von Baustoffen zur Anwendung kommen, konnen fur Beton keine vollig zufriedenstellende Bewertung liefern. Im vorliegenden Beitrag wird zur Darstellung der Feuchtespeicherfunktion von Beton und zur Verwendung in hygrothermischen Berechnungen eine empirische Funktion mit drei Zweigen formuliert. Die Formulierung dieser Beziehung wird analytisch prasentiert. Der vorgeschlagene Ausdruck kann an einen Betonbaustoff angepasst werden, wenn fur diesen Betonbaustoff lediglich die Werte fur den Sattigungsfeuchtegehalt (freie Sattigung, relative Feuchte 100 %) und den Feuchtegehalt bekannt sind, der 80 % relativer Luftfeuchte entspricht.

Traditional measures of competition are inappropriate for banking markets and there exists no consensus alternative measure. As a direct consequence, the empirical relationship between interbank competition and financial stability remains unclear. This paper adopts ideas from the new industrial organisation literature to measure interbank competition in the early twentieth-century Dutch rural market for small-scale deposits using newly collected data. It finds that transaction and information switching costs are both important sources of banks' market power.

Although it is traditionally thought that drainage basins are geometrically similar, we present new results which indicate that the aspect ratio of weakly dissected river basins at large scales (10–103 km2) depends on the surface slope: steeper surfaces develop narrower and lengthier basins whereas more gently dipping surfaces develop more equant and wider basins. This relationship is interpreted to be related to the nature of water flow over rough surfaces, with steeper slopes causing less flow convergence and lengthier and narrower basins. We derive an empirical relationship that can be used to infer the slope of a surface on which a river basin acquired its geometry based solely on a measure of its basin form. This relation provides a unique means of inferring the relative chronology of river basin development with respect to surface tilting and therefore provides a direct link between river basin morphology and tectonics.

This article provides new evidence on the empirical relationship between inflation and relative prices in the United States. In line with the predictions of recent monetary search models, we find that the impact of expected inflation on relative price variability (RPV) has disappeared during the recent period when inflation expectations have been stabilized on a low level. Endogenous break-point tests are applied to identify the timing and to confirm the significance of the changing role of inflation for RPV. The empirical findings are robust with respect to different price indices, disaggregation levels, and measurement concepts.

Do politics affect trade policy? Despite an extensive literature examining the relationship between trade policy and some political factors, relatively few studies have explored the role of a country's electoral system, arguably one of the most fundamental characteristics of a nation's political landscape. This paper examines the empirical relationship between tariffs and electoral systems across countries and over time. The broad theoretical framework is provided by Grossman and Helpman, which predicts a bias towards a non-zero average tariff, i.e. a “protectionist bias”, in countries with majoritarian systems, since politicians in a majoritarian system aim to maximize the welfare of their home districts, as opposed to the welfare of the nation as a whole. I compare average tariffs of countries with majoritarian systems to those with proportional systems, using methods that address the omitted variables/sample selection problem inherent to this analysis. I find that countries with majoritarian systems do indeed appear to have higher average tariffs than do countries with proportional systems. This result holds after controlling for other country-specific characteristics, such as a country's legal origins, colonial history, and geographic location.

From the consideration of thermal energy, the maximum intensity of tropical cyclones largely depends upon the Sea Surface Temperature (SST). In this paper an empirical relationship between SST and Maximum Potential Intensity (MPI) of tropical cyclones over the Bay of Bengal has been developed using a sample of 60 cyclones from 20 years data (1981–2000). The relationship between SST and MPI is found to be linear. The MPI of each storm is computed using this empirical relationship and compared with observed intensity to examine how close the cyclones come to reaching their MPI. The result shows that about 18% of cyclones reach more than 80% of their MPI and about 38% of cyclones reach more than 50% of their MPI at their peak intensity. In general, cyclones attain about 51% of their MPI. The inter-seasonal variability shows cyclones in the pre-monsoon and the post-monsoon seasons tend to reach a higher percentage of their MPI than in the monsoon season. The inter-annual variability suggests there is appreciable variation in the yearly average of the ratio of observed maximum intensity to the MPI. The MPI could provide useful information to a forecaster about the possible extreme intensity of tropical cyclones, which has direct relevance to disaster management preparedness. Copyright © 2008 Royal Meteorological Society

Aim This study aims to improve the formulation and results of the Brazilian Center for Weather Forecasting and Climate Studies Potential Vegetation Model (CPTECPVM) by developing a new parameterization for the long-term occurrence of fire in regions of potential savannas in the tropics. Compared with the relatively slow processes of carbon uptake and growth in vegetation, fast mortality and biomass consumption by fires may favour grasses and reduce tree coverage. Location The tropics. Methods For finding large-scale relationships between fires and other environmental factors, we made two main simplifying assumptions. First, lightning is the most important source of ignition for natural fires. Second, over continental areas in the tropics, lightning is mainly related to the zonal flux of moisture transport. Results The parameterization of fire occurrence was built based on a simple empirical relationship, combining information on mean and intra-annual variance of the zonal wind. Main conclusions The implementation of this new relationship improved the formulation and the results of the CPTEC-PVM. As a result of this new parameter, the accuracy of the model in allocating the correct vegetation (seasonal forests) instead of savannas for large regions in India and Southeast Asia is now substantially higher than in previous studies.

This article extends recent research on partisan agenda control in the U.S. House of Representatives to the issue of procedural control of the legislative agenda via special rules. In particular, we draw out a facet of cartel and conditional party government theories that has not been addressed in prior analyses: the simultaneous interrelationship between positive and negative agenda control. Using roll-call data on two procedural matters—votes to order the previous question on a special rule and votes to adopt a special rule—over the 1953–2002 period, we found that, in the area of procedural control of the floor agenda, the majority party’s amount of agenda control depends to a significant degree upon the party’s homogeneity and power. In recent work, Cox and McCubbins (2002, 2005) have elaborated on their theory of parties in Congress by focusing on the ability of the majority party, as a procedural cartel, to control the floor agenda of the U.S. House of Representatives. In this article, we build upon their efforts by considering the concept of agenda control as it relates to one of the primary mechanisms used to shape the floor agenda: procedural decisions contained in the special rules that govern consideration of bills coming before the House. Prior research has been largely confined to questions surrounding the nature of special rules, while the variation in the use of special rules and changes in party success in this area have received much less attention. To further our understanding of this aspect of legislative organization, and to elaborate the theoretical and empirical relationship between positive and negative agenda control, we take as our starting point two closely related perspectives, cartel theory and conditional party government theory. We posit that, although there are not large-scale conflicts between the two theories, there are some differences between them with regard to procedural control.

The spatial intensities of both industries and population are highly uneven across space. Moreover, these intensities differ not only across industries, but also change through time. Nevertheless, we show using Japanese data for metropolitan areas in two time periods that the location intensities of both industries and population are linked by surprisingly simple and persistent patterns. In particular, we identify a strong negative log-linear relation between the number and the average (population) size of metro areas in which a given industry is found. This relation, which we designate as the Number-Average Size (NAS) Rule, is also shown to be intimately connected to both the Rank-Size Rule and Christaller's (1966) Hierarchy Principle applied to metropolitan areas. In particular, we show mathematically that in the presence of the Hierarchy Principle (which holds quite well in Japan) this NAS Rule is essentially equivalent to the Rank Size Rule.