bluuebunny/crossref_metadata_2025_split huggingface dataset:
The immediate cause of the diurnal changes of nitrogen metabolism in leaves of nitrate‐replete tobacco: a major imbalance between the rate of nitrate reduction and the rates of nitrate uptake and ammonium metabolism during the first part of the light period
Authors: Matt P. , Geiger M. , Walch‐Liu P. , Engels C. , Krapp A. , Stitt M. 
Published: January 2004

ABSTRACTTo assess how diurnal changes of nitrate reductase (NIA) expression in leaves interact with upstream and downstream processes during nitrate utilization, nitrate uptake, and nitrate and ammonium metabolism were investigated at several times during the diurnal cycle in wild‐type tobacco. Plants were grown hydroponically on 2 mM nitrate to exclude possible complications due to changes in the external availability of nitrate, and to allow nitrate uptake to be measured in the growth conditions. (a) In leaves, the NIA transcript decreases during the day and recovers at night, and NIA activity increases three‐fold during the first part and declines during the second part of the light period. Nitrate decreases during the day and recovers at night, ammonium, glutamine, glycine and serine increase during the day and decrease at night, and 2‐oxoglutarate increases three‐fold after illumination and decreases during the last part of the light period. The amplitudes of the diurnal changes are similar to or larger than in tobacco grown on high nitrate in sand. The transcript for plastid glutamine synthetase (GLN2) is low at the end of the night and increases during the day, and glutamine synthetase activity increases to a peak at the end of the day and decreases at night. (b) In the roots, transcript levels for the high affinity nitrate transporter (NRT2) increase in the day and decrease at night. Nitrate uptake is about 40% higher during the day than at night. (c) Comparison of the diurnal changes of the leaf metabolite pools with the rate of nitrate uptake allows diurnal changes in fluxes to be estimated. During the first part of the light, the rate of nitrate assimilation is about two‐fold higher than the rate of nitrate uptake, and also exceeds the rate at which reduced nitrogen is metabolized in the GOGAT pathway. The resulting decrease of leaf nitrate and accumulation of nitrogen in intermediates of ammonium metabolism and photorespiration represent about 40 and 15%, respectively, of the total nitrate that enters the plant in 24 h. Later in the diurnal cycle as NIA expression and activity decline, this imbalance is reversed. NRT2 expression and nitrate uptake remain relatively high, and nitrate taken up during the night is used to replenish the leaf nitrate pool. Increased GLN2 expression in leaves during the second part of the light period allows continued assimilation of ammonium released during photorespiration and remobilization of the reduced nitrogen that accumulated earlier in the diurnal cycle.
Why aren't all Truck Drivers Owner‐Operators? Asset Ownership and the Employment Relation in Interstate for‐hire Trucking
Authors: Nickerson Jack A. , Silverman Brian S. 
Published: January 2004

Transaction‐cost and agency theorists have frequently cited trucks as prototypical user‐owned assets, and have consequently predicted a predominance of self‐employed drivers who contract with motor carriers. In fact, owner‐operators accounted for less than one‐third of US trucking activity conducted by large interstate trucking firms in 1991, a proportion that has changed little since deregulation. Given the predictions of organizational economists, why is self‐employment in the interstate trucking industry not the dominant organization form?We propose that transaction costs and agency costs are indeed important in the trucking industry. In the absence of externalities across hauls, contracting between carriers and owner‐operators is preferred for traditional agency reasons. However, when the outcome of one haul imposes externalities on other hauls or on the carrier's reputation, an owner‐operator will not internalize all costs associated with poor outcomes. Given problems of noncontractibility of maintenance effort, carrier ownership of the vehicle is the preferred organizational form in such a case. We also propose that vehicle idiosyncrasy can create thin market conditions that encourage carrier ownership of vehicles. A study of the organization and operations of 354 trucking firms for 1991 provides evidence consistent with these predictions.
Traded and Nontraded Goods and Real Wages
Authors: Beladi Hamid , Batra Ravi 
Published: January 2004

AbstractThe paper explains most, if not all, observations made by the empirical literature regarding the behavior of skilled and unskilled real wages in the United States, especially those since 1980. Generalizing the Stopler–Samuelson theorem, the authors show that the nontraded sector is critical to explaining the effects of changes in the price of traded goods on relative and absolute wages. Factor‐intensities play their role as in the traditional Stolper–Samuelson model, but the output of the nontraded sector matters as well. Specifically, freer trade benefits capital and hurts both the skilled and unskilled labor if the import as well as the nontraded sectors contract. This is a new result to the literature on Stolper–Samuelson issues.
Household Strategies of Coping with Shocks in Post‐crisis Russia
Authors: Lokshin Michael M. , Yemtsov Ruslan 
Published: January 2004

AbstractThe paper looks at the subjective evaluations of a number of coping strategies that respondents undertook to mitigate the effect on their welfare of the Russian financial crisis. Given the dramatic drop in formal cash incomes, how are people able to adapt? What are the relative importance and effectiveness of coping strategies to resist hardship in reducing poverty for different groups of households? The results of the analysis indicate that the choices of survival strategies are determined by the level of human capital in the household. The higher the household human capital, the more likely the household is to choose active strategies. Households with low human capital, households headed by pensioners, and low‐educated households are more likely to be socially excluded. A specific set of policy interventions should be targeted on such households to avoid the entrenchment of poverty, and the trend toward marginalization and impoverishment of these groups should be expressly monitored.
Is an Exhaustible Resource Economy Sustainable?
Authors: Farzin Y. Hossein 
Published: January 2004

AbstractThe paper focuses on two alternative concepts of sustainability dominating the literature: (i) maximum permanently maintainable consumption level (Fisherian income) and (ii) the amount of consumption that leaves total value of wealth intact (Hicksian income). In the context of a pure exhaustible resource economy, the author derives an explicit relationship between the two sustainability criteria and shows that while such an economy is not sustainable in the former sense, itisin the latter sense provided social preferences are represented by a logarithmic utility function. The implications of the two concepts for greening of national income are derived. Finally, the paper shows the range of values of the parameters of the model for which the utilitarian optimal path can be close to paths satisfying the alternative sustainability criteria, suggesting that such outcomes are less likely for very poor resource‐dependent countries than for the rich ones.
Consequences of Imitation by Poor Countries on International Wage Inequalities and Global Growth
Authors: Kind Hans Jarle 
Published: January 2004

AbstractThe paper presents an endogenous growth model where the level of international transaction costs may be decisive for whether the relatively poor East specializes in agriculture production, imitates goods from the rich West, or makes its own innovations. The author shows that the East produces only agricultural goods if transaction costs are high, while innovation is profitable when transaction costs are low. In between there are a range of transaction costs where the East imitates, possibly resulting in a lower global growth rate and a larger international wage gap than if imitation were not possible.
Effectiveness of Capital Controls: the Case of Brazil
Authors: Miles William 
Published: January 2004

AbstractThe emerging market crises of the past decade have led some observers to question the wisdom of a completely open capital account. But even if capital controls are desirable, empirical evidence is needed to demonstrate when and under what circumstances restrictions are effective. This paper investigates this issue for Brazil. Much analysis of policy effectiveness has been conducted with vector autoregressions. The validity of policy inference based on this technique has been cast into doubt, so this paper employs a more “narrative” method, modeling flows to Brazil as ARMAX processes. This approach yields the interesting result that controls can be effective when the reaction of financial market participants to restrictions is taken into account, and derivatives and debt market activities curtailed.
A Barrier to the Diffusion of Tacit Knowledge
Authors: Takii Katsuya 
Published: January 2004

AbstractThe paper examines the impact of skill transfer on economic growth. Even if there are the benefits of backwardness and the ability to absorb them, the South may not exploit them, because the skilled workers in the North are not willing to come to the South owing to their high opportunity cost. It is shown that if the South's relative income is low, the South cannot offer high wages to attract skilled workers from the North, and stays in the low rank. But if its relative income is high enough, exploiting the benefits of backwardness, it attains high growth and converges to a relatively higher position. This prediction is consistent with the evidence that the world distribution of relative income has two peaks. The study also shows that an increase in human capital in the North increases the minimum requirement for human capital in the South to soar.
Using Quality of Interview Information to Assess Nonrandom Attrition Bias in Developing‐Country Panel Data
Authors: Maluccio John A. 
Published: January 2004

AbstractPanel data often provide an understanding of household behavior not possible with cross‐sectional information alone. However, a disturbing feature of such data is that there can be substantial, nonrandom attrition and many analysts share the concern that this inhibits the ability to make accurate inferences. The author examines attrition in the KwaZulu–Natal Income Dynamics Study 1993–1998, assesses the extent of attrition bias for a specific empirical example, and proposes and implements a selection correction methodology using quality of first round interview variables as identifying instruments. The results show that attrition does lead to statistical bias in the “behavioral” coefficients in estimation of household‐level expenditure functions. Since it is typically difficult to determine the bias for a particular analysis a priori, and such bias is by its nature model‐specific, it behooves researchers using panel data to evaluate the effects of attrition in their analyses.
Measuring the Impact of Various Income Sources on the Link between Inequality and Development: Implications for the Kuznets Curve
Authors: Deutsch Joseph , Silber Jacques 
Published: January 2004

AbstractTo understand the link between inequality and development, a decomposition of the Gini index by income sources is used that emphasizes the role of three components measuring the impact of the shares of the sources, the degree to which they are unequally distributed, and their correlation with total income. Such a breakdown explains why the rising section of the Kuznets curve is mainly the consequence of the increasing share of wages while its declining section reflects the decreasing share of entrepreneurial income and the negative correlation between transfers and total income. The data sources were provided by the International Labour Office.
Simple Model of Resource Degradation and Agricultural Productivity in a Subsistence Economy
Authors: Sylwester Kevin 
Published: January 2004

AbstractResource degradation poses problems in many developing countries. In the model presented in the paper, current agricultural production lowers future land productivity. Since agents must produce to meet current subsistence needs, this can lead to a poverty trap in which land quality is continuously degraded over time. However, the model shows that not all subsistence farmers fall into this trap, although it might be difficult in practice to distinguish among those belonging to each case. The model also demonstrates why government programs such as income transfers, loans, and price controls might have differing effects upon economic outcomes depending upon the specific circumstances of farmers.
The Effect of Inequality on Growth: Theory and Evidence from the Indian States
Authors: Ghosh Sugata , Pal Sarmistha 
Published: January 2004

AbstractThe paper examines the effect of inequality on growth among the subnational states in India. Theoretically, growth of the regional economy is driven by productive public investment in the provision of health and education services financed by a linear output tax, and the optimum tax rate is determined by the median voter. In contrast to existing results, the authors obtain an ambiguous relationship between initial inequality and subsequent economic growth. Analysis of the Indian state‐level data suggests that rural inequality influences growth of total output more than urban inequality, and does so negatively. The indicator of intersectoral inequality is more important in explaining sectoral output growth.
Disability and risk of school related injury
Authors: Ramirez M , Peek-Asa C , Kraus J F 
Published: February 2004

Objective:Approximately six million children with disabilities attend school in the United States. Cognitive and physical limitations may compromise their ability to handle environmental hazards and hence increase their risk for injury. The objective of this study was to describe the epidemiology of school related injury among children enrolled in 17 special education schools in one large, urban school district.Design:Altogether 6769 schoolchildren with disabilities were followed up from 1994–98. Injury and population data were collected from pupil accident reports and existing school records. Associations were estimated through generalized estimating equations.Results:A total of 697 injuries were reported for a rate of 4.7/100 students per year. Children with multiple disabilities had a 70% increased odds of injury compared with the developmentally disabled (odds ratio (OR) 1.7, 95% confidence interval (CI) 1.3 to 2.3). The physically disabled (OR 1.4, 95% CI 1.0 to 1.9) had a modest increased odds of injury. Cuts, bruises, and abrasions composed almost three fourths of all injuries; almost half of these injuries were to the face. Falls (34%) and insults by other students (31%) were the most common external causes. More than a fourth of injuries were sports related, and 21% occurred on the playground/athletic field. Injury patterns differed across disabilities.Conclusions:Although limited to one school district, the population studied is the largest cohort thus far of schoolchildren with disabilities. With this large study base, potentially high risk groups were identified and circumstances of injury described. This information is imperative for developing and improving school based injury prevention measures.
Are older drivers actually at higher risk of involvement in collisions resulting in deaths or non-fatal injuries among their passengers and other road users?
Authors: Braver E R , Trempel R E 
Published: February 2004

Objectives:With more older drivers on the road, public concern has been expressed about their impact on traffic safety. This study revisited the question of driver age in relation to the risks of older drivers and others sharing the road with them, including pedestrians, passengers in the same vehicle, and occupants of other vehicles.Methods:Using United States federal data on fatal and non-fatal crashes, injury rates per driver were calculated for different types of road users. In addition, using data supplied by nine insurers, insurance claims per insured vehicle year were examined by driver age. The reference drivers were aged 30–59.Results:For fatal crashes, older drivers’ major impact on road users other than themselves was an increase in death rates among their passengers, who also tended to be elderly and thus more vulnerable to injuries (rate ratio (RR) for drivers aged 75+ 2.52; 95% confidence interval (CI) 2.39 to 2.66). For non-fatal crashes, drivers aged 75+ had a RR of 1.10 (95% CI 0.98 to 1.24) for involvement in collisions resulting in injuries to other passenger vehicles’ occupants compared with 30–59 year old drivers. The oldest drivers (aged 85+) had significant increases in insurance claims for injuries to other road users in crashes in which they were deemed at fault (RR 1.8; 95% CI 1.71 to 1.89).Conclusions:These findings suggest that the oldest drivers, a group with low average annual mileage, do pose some increased risks to occupants of other vehicles, and pose the most serious risks to themselves and their passengers.
ON THE STUDY OF ELECTROCHEMICAL TURBULENT NOISE IN A STIRRED VESSEL
Authors: MARTEMIANOV S. , DANAILA L. 
Published: January 2004

Electrochemical measurements of turbulent fluctuations of limiting diffusion current have been performed in a stirred reactor, where an axisymmetric mean flow is produced using a small cylindrical impeller. We used an electrochemical probe with three electrodes: two small circular electrodes geometrically included in another circular, large electrode. The first small electrode was in the centre of the large electrode, the second small electrode was near the leading edge. An electrochemical reaction is carried out on the surface of the electrodes, under conditions that the reaction rate is fast enough and the concentration of the reacting species is zero at the probe surface. Three signals are simultaneously measured, when the probe is placed very close to the agitator extremity. Spectral and wavelets analysis emphasize the presence of spikes for the three signals. There is significant evidence to indicate that a strong local energy concentration appears, at some particular frequencies. Further signal analysis is performed by calculating third-order and fourth-order structure functions (e.g. the skewness and flatness factors respectively). For each electrode, a different qualitative behaviour could be noted. This is an unexpected result for a "perfectly agitated" stirred reactor.
Inversion of magnetotelluric data for 2D structure with sharp resistivity contrasts
Authors: de Groot‐Hedlin Catherine , Constable Steven 
Published: January 2004

We have developed a linearized algorithm to invert noisy 2‐D magnetotelluric data for subsurface conductivity structures represented by smooth boundaries defining sharp resistivity contrasts. We solve for both a fixed number of subsurface resistivities and for the boundary locations between adjacent units. The boundary depths are forced to be discrete values defined by the mesh used in the forward modeling code. The algorithm employs a Lagrange multiplier approach in a manner similar to the widely used Occam method. The main difference is that we penalize variations in the boundary depths, rather than in resistivity contrasts between a large number of adjacent blocks. To reduce instabilities resulting from the breakdown of the linear approximation, we allow an option to penalize contrasts in the resistivities of adjacent units. We compare this boundary inversion method to the smooth Occam inversion for two synthetic models, one that includes a conductive wedge between two resistors and another that includes a resistive wedge between two conductors. The two methods give good agreement for the conductive wedge, but the solutions differ for the more poorly resolved resistive wedge, with the boundary inversion method giving a more geologically realistic result. Application of the boundary inversion method to the resistive Gemini subsalt petroleum prospect in the Gulf of Mexico indicates that the shape of this salt feature is accurately imaged by this method, and that the method remains stable when applied to real data.
Relative performance of moveout‐based multiple‐suppression methods for amplitude variation with offset (AVO) analysis and common midpoint (CMP) stacking
Authors: Alvarez Gabriel , Larner Ken 
Published: January 2004

We apply three moveout‐based methods for multiple suppression to simple synthetic common midpoint (CMP) gathers and compare their performance in terms of level of multiple rejection and, more importantly, in terms of (1) suitability of processed output for use in analysis of amplitude variations with offset (AVO), (2) primary‐to‐multiple amplitude (p/m) ratio of the data after CMP stacking, and (3) preservation of primary wavelet shape and amplitude on the stack. The three approaches are filtering in the frequency–wavenumber f–k domain, the Hampson method of filtering in the parabolic Radon transform domain, and a hybrid method that improves upon Hampson's approach by using a variation of Harlan's statistical pattern recognition approach to separate primaries from multiples in the parabolic Radon transform domain. The f–k approach is unsuitable prior to AVO analysis; moreover, it is little better in suppressing the multiples than the CMP stack itself. Hampson's method performs considerably better and is suitable for both purposes, although it can yield distorted AVO response where multiples are relatively strong on input. At about 50% additional computation effort over that of Hampson's method, the hybrid approach has superior treatment of amplitude behavior with offset. For many situations, the hybrid method yields up to twice the primary‐to‐multiples amplitude ratio on the CMP stack.
Voriconazole in Fungal Keratitis Caused by Scedosporium apiospermum
Authors: Prats Hernández Carmen , Tello Francisca Llinares , José Amparo Burgos San , Otaolaurruchi Juan Selva , Baines Juan Pablo Ordovás 
Published: February 2004

OBJECTIVE To describe the first case, to the best of our knowledge, of posttraumatic Scedosporium apiospermum (ScA) keratitis successfully treated with systemic and topical voriconazole. CASE SUMMARY A 19-year-old man was admitted to the hospital with an incisive wound of his left eye and the cornea totally sectioned after trauma with a cutter used in gardening. Initial empirical treatment was followed by systemic and topical voriconazole, and the eye did not have to be enucleated. Five months after the trauma, a penetrating keratoplasty and chamber intraocular lens implantation was performed with a favorable visual outcome. DISCUSSION ScA keratitis is rare, but it must be suspected if a history of ocular injury with contaminated objects exists. Among the antifungals available to treat ScA keratitis, voriconazole has shown advantages such as the lowest minimum inhibitory concentration and the availability of an oral formulation. CONCLUSION Voriconazole shows promise as an effective alternative to conventional antifungals in the treatment of ScA keratitis. It is available both as oral and intravenous preparations, which is a great advantage in these lengthy infections.