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Reallocation
Selected AbstractsCapital Inflows, Resource Reallocation and the Real Exchange Rate,INTERNATIONAL FINANCE, Issue 2 2008Emmanuel K. K. Lartey A large capital inflow to a developing economy can potentially cause a real exchange rate appreciation that is detrimental to the prospects of its tradable sector; a phenomenon known as the Dutch Disease. I analyse the effects of both the level and share of capital inflow on resource reallocation and real exchange rate movements in a small open economy. I find that there exists a trade-off between resource reallocation and the degree of real exchange rate appreciation. In particular, the less labour the tradable sector loses to the non-tradable sector, the greater is the real exchange rate appreciation. This result is driven by the share of investment accounted for by foreign capital, and suggests that an emerging market economy that adopts a production technique which utilizes a greater share of foreign capital relative to domestic capital will be more susceptible to the Dutch Disease following an increase in capital inflow. The results also imply that a policy designed to minimize real exchange rate appreciation during capital inflow episodes should encompass measures aimed at stabilizing prices of non-tradables. [source] The Antitrust Implications of Capacity Reallocation by a Dominant FirmTHE JOURNAL OF INDUSTRIAL ECONOMICS, Issue 2 2001Ian Gale When a firm acquires rival firms in one market, and moves their capacity to another market, should antitrust authorities be concerned? We address this question by studying a multi-stage game. A dominant firm has the opportunity to acquire fringe firms that operate in the same market. Then, the dominant firm has the opportunity to move capacity from that market to a second market. The model is motivated by a series of acquisitions in the Specialized Mobile Radio industry aimed at establishing a new cellular carrier. We derive necessary and sufficient conditions for the dominant firm to acquire too little capacity relative to the social optimum. The results shed light on the Consent Decree negotiated in US v. Motorola Inc. and Nextel Communications Inc., 1994. [source] The Impact of Trade on Intra-Industry Reallocations and Aggregate Industry ProductivityECONOMETRICA, Issue 6 2003Marc J. Melitz This paper develops a dynamic industry model with heterogeneous firms to analyze the intra-industry effects of international trade. The model shows how the exposure to trade will induce only the more productive firms to enter the export market (while some less productive firms continue to produce only for the domestic market) and will simultaneously force the least productive firms to exit. It then shows how further increases in the industry's exposure to trade lead to additional inter-firm reallocations towards more productive firms. The paper also shows how the aggregate industry productivity growth generated by the reallocations contributes to a welfare gain, thus highlighting a benefit from trade that has not been examined theoretically before. The paper adapts Hopenhayn's (1992a) dynamic industry model to monopolistic competition in a general equilibrium setting. In so doing, the paper provides an extension of Krugman's (1980) trade model that incorporates firm level productivity differences. Firms with different productivity levels coexist in an industry because each firm faces initial uncertainty concerning its productivity before making an irreversible investment to enter the industry. Entry into the export market is also costly, but the firm's decision to export occurs after it gains knowledge of its productivity. [source] Post-ingestive effects of nectar alkaloids depend on dominance status of bumblebeesECOLOGICAL ENTOMOLOGY, Issue 4 2009JESSAMYN S. MANSON Abstract 1.,Secondary metabolites have acute or chronic post-ingestive effects on animals, ranging from death to growth inhibition to reduced nutrient assimilation. 2.,Although characterised as toxic, the nectar of Gelsemium sempervirens is not lethal to pollinators, even when the concentration of the nectar alkaloid gelsemine is very high. However, little is known about the sublethal costs of nectar alkaloids. 3.,Using a microcolony assay and paired worker bumblebees, the present study measured the effects of artificial nectar containing gelsemine on oocyte development. Oocytes are a sensitive indicator of protein utilisation and general metabolic processes. We also calculated carbohydrate concentrations in the haemolymph to examine energetic costs of gelsemine consumption. 4.,High concentrations of gelsemine significantly reduced mean oocyte width in subordinate bees, while dominant bees showed only a trend towards oocyte inhibition. Gelsemine consumption did not reduce carbohydrate concentrations in haemolymph. 5.,The cost of ingesting gelsemine may be due to direct toxicity of alkaloids or may be an expense associated with detoxifying gelsemine. Detoxification of alkaloids can require reallocation of resources away from essential metabolic functions like reproduction. The risks associated with nectar alkaloid consumption are tied to both the social and nutritional status of the bee. [source] The Impact of Uncertainty ShocksECONOMETRICA, Issue 3 2009Nicholas Bloom Uncertainty appears to jump up after major shocks like the Cuban Missile crisis, the assassination of JFK, the OPEC I oil-price shock, and the 9/11 terrorist attacks. This paper offers a structural framework to analyze the impact of these uncertainty shocks. I build a model with a time-varying second moment, which is numerically solved and estimated using firm-level data. The parameterized model is then used to simulate a macro uncertainty shock, which produces a rapid drop and rebound in aggregate output and employment. This occurs because higher uncertainty causes firms to temporarily pause their investment and hiring. Productivity growth also falls because this pause in activity freezes reallocation across units. In the medium term the increased volatility from the shock induces an overshoot in output, employment, and productivity. Thus, uncertainty shocks generate short sharp recessions and recoveries. This simulated impact of an uncertainty shock is compared to vector autoregression estimations on actual data, showing a good match in both magnitude and timing. The paper also jointly estimates labor and capital adjustment costs (both convex and nonconvex). Ignoring capital adjustment costs is shown to lead to substantial bias, while ignoring labor adjustment costs does not. [source] Implication of the glutamine synthetase/glutamate synthase pathway in conditioning the amino acid metabolism in bundle sheath and mesophyll cells of maize leavesFEBS JOURNAL, Issue 12 2008Marie-Hélène Valadier We investigated the role of glutamine synthetases (cytosolic GS1 and chloroplast GS2) and glutamate synthases (ferredoxin-GOGAT and NADH-GOGAT) in the inorganic nitrogen assimilation and reassimilation into amino acids between bundle sheath cells and mesophyll cells for the remobilization of amino acids during the early phase of grain filling in Zea mays L. The plants responded to a light/dark cycle at the level of nitrate, ammonium and amino acids in the second leaf, upward from the primary ear, which acted as the source organ. The assimilation of ammonium issued from distinct pathways and amino acid synthesis were evaluated from the diurnal rhythms of the transcripts and the encoded enzyme activities of nitrate reductase, nitrite reductase, GS1, GS2, ferredoxin-GOGAT, NADH-GOGAT, NADH-glutamate dehydrogenase and asparagine synthetase. We discerned the specific role of the isoproteins of ferredoxin and ferredoxin:NADP+ oxidoreductase in providing ferredoxin-GOGAT with photoreduced or enzymatically reduced ferredoxin as the electron donor. The spatial distribution of ferredoxin-GOGAT supported its role in the nitrogen (re)assimilation and reallocation in bundle sheath cells and mesophyll cells of the source leaf. The diurnal nitrogen recycling within the plants took place via the specific amino acids in the phloem and xylem exudates. Taken together, we conclude that the GS1/ferredoxin-GOGAT cycle is the main pathway of inorganic nitrogen assimilation and recycling into glutamine and glutamate, and preconditions amino acid interconversion and remobilization. [source] How Did the 2003 Dividend Tax Cut Affect Stock Prices?FINANCIAL MANAGEMENT, Issue 4 2008Gene Amromin We test the hypothesis that the 2003 dividend tax cut boosted US stock prices and thereby lowered the cost of equity capital. Using an event-study methodology, we attempt to identify an aggregate stock market effect by comparing the behavior of US common stock prices with that of foreign equities and the equities of real estate investment trusts (REITs). We also examine the relative cross-sectional response of prices of high- and low-dividend-paying stocks. We do not find any imprint of the dividend tax cut news on the value of the aggregate US stock market. On the other hand, high-dividend stocks outperformed low-dividend stocks by a few percentage points over the event windows, suggesting that the tax cut may have induced asset reallocation within equity portfolios. Finally, the positive abnormal return on nondividend paying US stocks in 2003 does not appear to be tied to tax cut news. [source] Control of tiller recruitment in bunchgrasses: uniting physiology and ecologyFUNCTIONAL ECOLOGY, Issue 4 2004K. W. TOMLINSON Summary 1Bunchgrasses are clonal plants whose dominance of moist grasslands worldwide is maintained largely through tiller recruitment. Tiller recruitment in clonal plants is a subset of the problem of lateral bud outgrowth in higher plants. This paper proposes that three currently competing hypotheses of lateral bud outgrowth , apical dominance; the nutrition hypothesis; and photosensitivity to the red : far-red light ratio , all operate in a manner dependent on environment and plant form. 2The evidence for each hypothesis is reviewed, following which an integrated model is provided that links the three hypotheses into a cohesive strategy. Consequently we assess tiller recruitment by bunchgrasses in terms of the constraints of their functional growth form and their environment. Of the mineral nutrients, only nitrogen is considered because it is the only nutrient whose relationship with tiller recruitment is well established. 3The integrated model maintains the accepted paradigm that actual bud release is hormonally controlled by the auxin : cytokinin ratio, although local nutrient concentrations may also be inhibitory. Importantly, each hormone is controlled by local signals in the shoots and roots, respectively, facilitating appropriate responses to environmental conditions. Auxin production and export from the shoots is moderated by phytochrome responses to red : far-red light ratios. Cytokinin production is mediated by root N concentration which, in turn, is a function of N absorption from the soil and seasonal reallocation of tissue N. 4The growth form of bunchgrasses and the environment in which they are found emphasize that N has a strong mediatory role over tiller production which allows the grass plant to respond appropriately to shifts in this limiting resource. This suggests that control of lateral bud outgrowth may have an evolutionary basis in resource competition for N. [source] The application of an empowerment modelHUMAN FACTORS AND ERGONOMICS IN MANUFACTURING & SERVICE INDUSTRIES, Issue 4 2001Eric Molleman In this study we applied an empowerment model that focuses on (a) the need for empowerment in light of organizational strategy, (b) job design issues such as job enlargement and job enrichment that facilitate empowerment, and (c) the abilities, and (d) the attitudes of workers that make empowerment work. We applied the model in the manufacturing department of a firm that produces catheters for medical use and interviewed managers and supporting staff and surveyed 231 operators. The leading performance indicators in this firm are efficiency and quality. The reassignment of 12 out of 33 tasks was believed to contribute to these organizational objectives. For most workers, their abilities and their attitudes toward empowerment proved to be no major barrier to the reallocation of these tasks. However, for temporary workers, mainly working in a "short shift," the leeway to learn skills is limited, which probably impedes empowerment. The study shows that our model helps to diagnose the need for empowerment, to design work structures that facilitate empowerment, and to select appropriate human resource management practices. Further validation in other organizational settings is desirable. © 2001 John Wiley & Sons, Inc. [source] Capital Inflows, Resource Reallocation and the Real Exchange Rate,INTERNATIONAL FINANCE, Issue 2 2008Emmanuel K. K. Lartey A large capital inflow to a developing economy can potentially cause a real exchange rate appreciation that is detrimental to the prospects of its tradable sector; a phenomenon known as the Dutch Disease. I analyse the effects of both the level and share of capital inflow on resource reallocation and real exchange rate movements in a small open economy. I find that there exists a trade-off between resource reallocation and the degree of real exchange rate appreciation. In particular, the less labour the tradable sector loses to the non-tradable sector, the greater is the real exchange rate appreciation. This result is driven by the share of investment accounted for by foreign capital, and suggests that an emerging market economy that adopts a production technique which utilizes a greater share of foreign capital relative to domestic capital will be more susceptible to the Dutch Disease following an increase in capital inflow. The results also imply that a policy designed to minimize real exchange rate appreciation during capital inflow episodes should encompass measures aimed at stabilizing prices of non-tradables. [source] Structural Traps, Politics and Monetary PolicyINTERNATIONAL FINANCE, Issue 1 2004Robert H. Dugger Structural conditions pose a challenge to monetary policy, as the example of Japan shows. In this paper we develop the concept of structural trap, where the interplay of long-term economic development incentives, politics, and demographics results in economies being unable to efficiently reallocate capital from low- to high-return uses. The resulting macroeconomic picture looks like a liquidity trap , low GDP growth and deflation despite extreme monetary easing. But the optimal policy responses are very different and mistaking them could lead to perverse results. The key difference between a liquidity trap and a structural one is the role of politics. We show how, in the Japanese case, longstanding economic incentives and protections and demographic trends have resulted in a political leadership that resists capital reallocation from older protected low-return sectors to higher-return newer ones. If the Japanese case is instructive, in a structural trap, extremely loose monetary policy perpetuates deflation and low GDP growth, because unproductive but politically important firms are allowed to survive and capital reallocation is prevented. By preventing the needed reduction in excess capacity, a structural trap condemns reflationary policies to failure by making the creation of credible inflation expectations impossible. Faced with a structural trap, an independent central bank with a price stability mandate should adopt a monetary policy stance consistent with restructuring. If political resistance is high, monetary policy decision makers will need to keep nominal rates high enough to ensure that capital reallocation takes place at an acceptable pace. [source] Energy metabolism in young pigs as affected by establishment of new groups prior to transportJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 5-6 2002M. J. W. HEETKAMP Energy metabolism was studied in 9-week-old-pigs as affected by mixing just before transport. In each of three trials, two groups of 20 pigs (two litters of 10) were randomly assigned to one of two treatments: control and mixing. Each group was housed in one of two climatic chambers with each subgroup in one of two pens. In each trial, the two litters within the mixing treatment were mixed, just before transport, at the start of a 2-week experimental period. In the control treatment, the social structure of both litters in each trial was not altered. In both treatments, large alterations of energy partitioning from week 1 to week 2, are probably signs of recovering from transportation and/or adaptation to new feeding and housing conditions. Mixing just before transport did not change total energy metabolism but only increased nonactivity-related heat production by 3.1% for the total experimental period. Most likely, long-term performance is also not affected negatively by mixing. Animals seem to be able to change energy expenditure on activity when more energy is required for other physiological processes. This symptom of possible reallocation of energy between different vital live processes (e.g. behavior, protein turn-over) might be one of the first indications of an impaired well-being. [source] A structural model of US aggregate job flowsJOURNAL OF APPLIED ECONOMETRICS, Issue 3 2002Fabrice Collard This paper contributes to the analysis of jobs flows dynamics through the explicit modelling of job creations and job destructions. We propose a simple matching model extended for endogenous separation and tractable heterogeneity. The parameters of the model are estimated using a simulation-based estimation method. We then test the ability of trade externalities, generated by the matching process, to (i) propagate reallocation and aggregate disturbances in the whole labor market and (ii) generate the observed distribution of aggregate job flows. The results clearly indicate that the model is able to match the dynamics of US aggregate job flows. Copyright © 2002 John Wiley & Sons, Ltd. [source] Cost of resistance to parasites in digital organismsJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 3 2007A. R. KRAAIJEVELD Abstract Virtually all organisms are attacked by parasites and are therefore expected to evolve resistance against these natural enemies. Parasite resistance is costly in a wide range of organisms, although the generality of such costs has been questioned, especially when resistance is not based on reallocation of resources. Digital organisms are increasingly used to explore aspects of life in general. In the Tierra system, there is a trade-off between resistance against parasites and competitive ability. Because digital organisms are too simple to store resources, the finding that resistance to parasites is costly in digital organisms suggests that costs of parasite resistance can also occur when resistance is not resource based. [source] Intertemporal analysis of employment decisions on agricultural holdings in SloveniaAGRICULTURAL ECONOMICS, Issue 2 2005Luka Juvan Employment decisions; Mobility of labor supply; Off-farm employment; Probit model Abstract The article attempts to quantify determinants influencing the dynamics of employment decisions on agricultural holdings in Slovenia and to test specific aspects of labor reallocation during the transition period by the application of an agricultural household model. Through the use of a 1991,2000 longitudinal data set for 22,055 farm households, quantitative analysis of intertemporal employment decisions by farm holders is carried out using probit techniques. The determinants tested relate to the personal characteristics of farm holders (gender, age, education level, and potential off-farm income), household characteristics (size, structure), characteristics of the agricultural holding (economic size, labor intensity), and local labor market conditions. The model results generally confirm existing empirical evidence on asymmetrical and irreversible participation of holders on the labor market. Despite intensive restructuring of agriculture and profound changes in the nonfarm labor market in the analyzed period, labor supply of farm holders remains rigid. The mobility of labor supply is lower than expected, which can be attributed to the importance of structural problems constraining intersectoral mobility. Low labor mobility reduces the efficiency of labor allocation on agricultural holdings in Slovenia. Elements of this problem emerge on both supply (e.g., low level of educational and professional attainment of reference persons) and demand sides of the labor market (e.g., unfavorable local labor market conditions). A marked tendency toward maintaining the same employment status is more distinct in the case of holders employed on-farm only. [source] Pollution and Cost in the Coke-Making Supply Chain in Shanxi Province, ChinaJOURNAL OF INDUSTRIAL ECOLOGY, Issue 3-4 2002Applying an Integrated System Model to Siting, Transportation Trade-Offs Summary An integrated system trade-off model has been developed to assess costs and pollution associated with transportation in the coke-making supply chain in Shanxi Province, China. A transportation-flow, cost-minimization solver is combined with models for calculating coke-making plant costs, estimating transportation costs from a geographic information system road and rail database, and aggregating coke-making capacity among plants. Model outputs of economic cost, nitrogen oxides (NOx) emissions, and transport distributions are visualized using an Internet-based graphic user interface. Data for the model were collected on survey trips to Shanxi Province as well as from secondary references and proxies. The modularity and extensibility of the system trade-off model facilitate introduction of new data sets in order to examine various planning scenarios. Scenarios of coke-making plant aggregation, rail infrastructure improvement, and technology transfer were evaluated using the model. Costs and pollution emissions can be reduced by enlarging coke-making plants near the rail stations and closing down other plants. Preferential minimization of transportation costs gives a lower total cost than simply minimizing plant costs. Therefore, policy makers should consider transportation costs when planning the reallocation of coke-making capacity in Shanxi Province. Increasing rail-transport capacity is less effective than aggregating plant capacity. On the other hand, transfer of low-pollution truck technology results in a large emission reduction, however, reflecting the importance of truck transportation in the Shanxi Province coke-making industry. [source] Floating without flotations,the exchange rate and the Mexican stock market: 1995,2001JOURNAL OF INTERNATIONAL DEVELOPMENT, Issue 3 2006Jesús Muñoz Abstract Pegged exchange rates in capital importing countries partially ,socialised' the risks of international borrowing. A corollary of managed floating, therefore, is a reallocation of risk bearing to private capital markets. Equity finance offers explicit risk sharing but Mexican experience since 1995 confirms that it may not expand spontaneously under a floating regime, despite buoyant international conditions. As an explanation for this disappointing outcome, the analysis highlights the implications of managed floating for equity demand when corporate debt is high. Policy must recognize that while firms need to reduce gearing, investors may not be attracted to the shares of indebted companies. Copyright © 2006 John Wiley & Sons, Ltd. [source] Regulated Firms with Transboundary Pollution: Does International Competition Improve Efficiency?JOURNAL OF PUBLIC ECONOMIC THEORY, Issue 3 2003Isabelle Péchoux We consider a model of strategic trade and environmental policies with transboundary pollution. A regulated monopoly produces in each country and emits pollution. Under complete information, opening borders leads to a reallocation of the production from the large country to the small one. Total production increases, leading to an increase in the total level of pollution. The creation of a common market sometimes leads to a deterioration of total welfare. Under asymmetric information, the international competition generated by the common market decreases the informational rents of the firms, thereby reinforcing the potential gain to open markets to international competition. [source] Equity Risk, Conversion Risk, and the Demand for InsuranceJOURNAL OF RISK AND INSURANCE, Issue 3 2003Rod Garratt Existing insurance theory fails when applied to real property because it does not account for variations in the economic environment. The article studies optimal property insurance in the presence of two sources of variation: equity risk and conversion risk. Equity risk is randomness of the value of a property. It tends to raise demand for conventional insurance. In contrast, conversion risk is randomness in the value the property would have if, after severe damage, it were converted to the highest-valued use. It is distinct from equity risk because the highest-valued use is typically not the current one. Under independent conversion risk, the optimum upper limit is a compromise among underlying conversion thresholds. Absent independence, the optimum can be quite different. Conversion risk can raise or lower the demand for property insurance. Insurance contracts that fail to address conversion tend to undermine the orderly disposition of obligations and reduce the gains from reallocation of risks through insurance. [source] Evaluation of pre-hospital trauma triage criteria: a prospective study at a Danish level I trauma centreACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 9 2007S. H. Kann Background:, The aim of the present study was to evaluate the precision of our trauma triage protocol [based on the American College of Surgeons, Committee on Trauma (ACS COT)] in identifying severely injured defined as an injury severity score (ISS) > 15. Our hypothesis was that isolated mechanism-of-injury criteria were responsible for a significant over-triage leading to over-use of our trauma team. Methods:, Design: A prospective cohort study. Setting: A level I trauma centre, Aarhus, Denmark. Patients and participants: Among all injured patients admitted during a 6-month period in 2003 we identified severely injured. During the study period, trauma team activations were consecutively registered and triage criteria were prospectively collected. Sensitivity, specificity, positive predictive value, over-triage and under-triage were calculated. Results:, Out of 15,162 patients in the emergency department, 848 injured patients were included and 59 (7%) were severely injured. We had 242 trauma team activations with 54 (22%) severely injured. Sensitivity was 92%, specificity 76%, giving an over-triage of 24% and an under-triage of 8%. The positive predictive value was 22%. Among 60 patients with mechanism-of-injury as the only criterion, five were severely injured in contrast to 12 out of 20 patients with mechanism-of-injury combined with physiological and/or anatomical criteria. Conclusion:, The positive predictive value of our triage protocol was low, only 22%. This was mainly as a result of a significant over-triage from isolated mechanism-of-injury criteria. We recommend revision of the triage protocol and reallocation of our trauma team resources. [source] Groundwater Banking in Aquifers that Interact With Surface Water: Aquifer Response Functions and Double-Entry Accounting,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 6 2009Bryce A. Contor Contor, Bryce A., 2009. Groundwater Banking in Aquifers That Interact With Surface Water: Aquifer Response Functions and Double-Entry Accounting. Journal of the American Water Resources Association (JAWRA) 45(6):1465-1474. Abstract:, Increasing worldwide demands for water call for mechanisms to facilitate storage of seasonal supplies and mechanisms to facilitate reallocation of water. Markets are economically efficient reallocation and incentive mechanisms when market conditions prevail, but special hydrologic and administrative conditions of water use and allocation interfere with required market conditions. Water banking in general can bring market forces to bear on water storage and reallocation, improving economic efficiency and therefore the welfare of society as a whole. Groundwater banking can utilize advantages of aquifers as storage vessels with vast capacity, low construction cost, and protection of stored water. For groundwater banking in aquifers that interact with surface water, an accounting system is needed that addresses the depletion of stored volumes of water as water migrates to surface water. Constructing such a system requires integration of hydrologic, economic, and legal principles with principles of financial accounting. Simple mass-balance accounting, even with allowances for depletion, is not adequate in these aquifers. Aquifer response functions are mathematical descriptions of the impact that aquifer pumping or recharge events have upon hydraulically connected surface water bodies. Double-entry accounting is a financial accounting methodology for tracking asset inventories and ownership claims upon assets. The powerful innovation of linking aquifer response functions with double-entry accounting technologies allows application of groundwater banking to aquifers where deposits can be depleted by migration to hydraulically connected surface water. It honors the hydrologic realities of groundwater/surface water interaction, the legal requirements of prior appropriation water law, and the economic requirements for equitable and efficient allocation of resources. [source] Short but catching up: Statural growth among native Amazonian Bolivian childrenAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 3 2010Ricardo Godoy The ubiquity and consequences of childhood growth stunting (<,2 SD in height-for-age Z score, HAZ) in rural areas of low-income nations has galvanized research into the reversibility of stunting, but the shortage of panel data has hindered progress. Using panel data from a native Amazonian society of foragers-farmers in Bolivia (Tsimane'), we estimate rates of catch-up growth for stunted children. One hundred forty-six girls and 158 boys 2 , age , 7 were measured annually during 2002,2006. Annual , height in cm and in HAZ were regressed separately against baseline stunting and control variables related to attributes of the child, mother, household, and village. Children stunted at baseline had catch-up growth rates 0.11 SD/year higher than their nonstunted age and sex peers, with a higher rate among children farther from towns. The rate of catch up did not differ by the child's sex. A 10% rise in household income and an additional younger sibling lowered by 0.16 SD/year and 0.53 SD/year the rate of growth. Results were weaker when measuring , height in cm rather than in HAZ. Possible reasons for catch-up growth include (a) omitted variable bias, (b) parental reallocation of resources to redress growth faltering, particularly if parents perceive the benefits of redressing growth faltering for child school achievement, and (c) developmental plasticity during this period when growth rates are most rapid and linear growth trajectories have not yet canalized. Am. J. Hum. Biol., 2010. © 2009 Wiley-Liss, Inc. [source] Seasonal and circadian variation in salivary testosterone in rural Bolivian menAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 6 2009Virginia J. Vitzthum Testosterone (T) plays a key role in the increase and maintenance of muscle mass and bone density in adult men. Life history theory predicts that environmental stress may prompt a reallocation of such investments to those functions critical to survival. We tested this hypothesis in two studies of rural Bolivian adult men by comparing free T levels and circadian rhythms during late winter, which is especially severe, to those in less arduous seasons. For each pair of salivary TAM/TPM samples (collected in a , 12-h period), circadian rhythm was considered classic (CCLASSIC) if TAM > 110%TPM, reverse (CREVERSE) if TPM > 110%TAM, and flat (CFLAT) otherwise. We tested the hypotheses that mean TAM > mean TPM and that mean TLW < mean TOTHER (LW = late winter, OTHER = other seasons). In Study A, of 115 TPM,TAM pairs, 51% = CCLASSIC, 39% = CREVERSE, 10% = CFLAT; in Study B, of 184 TAM,TPM pairs, 55% = CCLASSIC, 33% = CREVERSE, 12% = CFLAT. Based on fitting linear mixed models, in both studies TOTHER-AM > TOTHER-PM (A: P = 0.035, B: P = 0.0005) and TOTHER-AM > TLW-AM (A: P = 0.054, B: P = 0.007); TPM did not vary seasonally, and T diurnality was not significant during late winter. T diurnality varied substantially between days within an individual, between individuals and between seasons, but neither T levels nor diurnality varied with age. These patterns may reflect the seasonally varying but unscheduled, life-long, strenuous physical labor that typifies many non-industrialized economies. These results also suggest that single morning samples may substantially underestimate peak circulating T for an individual and, most importantly, that exogenous signals may moderate diurnality and the trajectory of age-related change in the male gonadal axis. Am. J. Hum. Biol., 2009. © 2009 Wiley-Liss, Inc. [source] The different fates of mitochondria and chloroplasts during dark-induced senescence in Arabidopsis leavesPLANT CELL & ENVIRONMENT, Issue 12 2007OLIVIER KEECH ABSTRACT Senescence is an active process allowing the reallocation of valuable nutrients from the senescing organ towards storage and/or growing tissues. Using Arabidopsis thaliana leaves from both whole darkened plants (DPs) and individually darkened leaves (IDLs), we investigated the fate of mitochondria and chloroplasts during dark-induced leaf senescence. Combining in vivo visualization of fates of the two organelles by three-dimensional reconstructions of abaxial parts of leaves with functional measurements of photosynthesis and respiration, we showed that the two experimental systems displayed major differences during 6 d of dark treatment. In whole DPs, organelles were largely retained in both epidermal and mesophyll cells. However, while the photosynthetic capacity was maintained, the capacity of mitochondrial respiration decreased. In contrast, IDLs showed a rapid decline in photosynthetic capacity while maintaining a high capacity for mitochondrial respiration throughout the treatment. In addition, we noticed an unequal degradation of organelles in the different cell types of the senescing leaf. From these data, we suggest that metabolism in leaves of the whole DPs enters a ,stand-by mode' to preserve the photosynthetic machinery for as long as possible. However, in IDLs, mitochondria actively provide energy and carbon skeletons for the degradation of cell constituents, facilitating the retrieval of nutrients. Finally, the heterogeneity of the degradation processes involved during senescence is discussed with regard to the fate of mitochondria and chloroplasts in the different cell types. [source] Adjustment of leaf photosynthesis to shade in a natural canopy: reallocation of nitrogenPLANT CELL & ENVIRONMENT, Issue 3 2005H. EICHELMANN ABSTRACT The present study was performed to investigate the adjustment of the constituents of the light and dark reactions of photosynthesis to the natural growth irradiance in the leaves of an overstorey species, Betula pendula Roth, a subcanopy species Tilia cordata P. Mill., and a herb Solidago virgaurea L. growing in a natural plant community in Järvselja, Estonia. Shoots were collected from the site and properties of individual leaves were measured in a laboratory, by applying a routine of kinetic gas exchange and optical measurements that revealed photosystem II (PSII), photosystem I (PSI), and cytochrome b6f densities per leaf area and the distribution of excitation (or chlorophyll, Chl) between the two photosystems. In parallel, N, Chl and ribulose-bisphosphate carboxylase-oxygenase (Rubisco) content was measured from the same leaves. The amount of N in photosynthetic proteins was calculated from the measured contents of the components of the photosynthetic machinery. Non-photosynthetic N was found as the residual of the budget. Growth in shade resulted in the decrease of leaf dry mass to a half of the DW in sun leaves in each species, but the total variation, from the top to the bottom of the canopy, was larger. Through the whole cross-section of the canopy, leaf dry weight (DW) and Rubisco content per area decreased by a factor of four, N content by a factor of three, but Chl content only by a factor of 1.7. PSII density decreased by a factor of 1.9, but PSI density by a factor of 3.2. The density of PSI adjusted to shade to a greater extent than the density of PSII. In shade, the distribution of N between the components of the photosynthetic machinery was shifted toward light-harvesting proteins at the expense of Rubisco. Non-photosynthetic N decreased the most substantially, from 54% in the sun leaves of B. pendula to 11% in the shade leaves of T. cordata. It is concluded that the redistribution of N toward light-harvesting Chl proteins in shade is not sufficient to keep the excitation rate of a PSII centre invariant. Contrary to PSII, the density of PSI , the photosystem that is in immediate contact with the carbon assimilation system , shade-adjusts almost proportionally with the latter, whereas its Chl antenna correspondingly increases. Even under N deficiency, a likely condition in the natural plant community, a substantial part of N is stored in non-photosynthetic proteins under abundant irradiation, but much less under limiting irradiation. At least in trees the general sequence of down-regulation due to shade adjustment is the following: (1) non-protein cell structures and non-photosynthetic proteins; (2) carbon assimilation proteins; (3) light reaction centre proteins, first PSI; and (4) chlorophyll-binding proteins. [source] The n -back as a dual-task: P300 morphology under divided attentionPSYCHOPHYSIOLOGY, Issue 6 2001Scott Watter The n -back task was hypothesized to be a dual task, permitting the imposition of parametrically increasing attentional and working memory demands, while keeping constant the demands of an embedded matching subtask. Visual targets were presented for 200 ms every 2.2 s at pseudorandomly varying positions on a computer screen. Participants were required to remember the most recent 0, 1, 2, or 3 positions and responded with a choice button push to whether the current target position matched the position presented n items previously. P300 peak latency was constant across n -back tasks, reflecting constant perceptual and cognitive demands of the matching subtask. P300 peak amplitude decreased with increasing memory load, reflecting reallocation of attention and processing capacity away from the matching subtask to working memory activity. These data support a dual-task nature of the n -back, which should be considered when employing this paradigm. [source] Business Management Reform in the Department of Defense in Anticipation of Declining BudgetsPUBLIC BUDGETING AND FINANCE, Issue 3 2007DOUGLAS A. BROOK Business management reform efforts have been part of the U.S. Defense Department agenda for decades. Current reform efforts have explicitly established the goal of generating, harvesting, and reinvesting savings from business management reform to buy more capital items; that is, they have focused on a measurable reallocation from operating and support costs to investment within a given budget top line. Recent increases in the defense top line, largely related to the war on terrorism, are not likely to persist; in addition, an examination of the factors affecting the top line suggests that a decline in the near term is likely. An examination of current and past defense management reforms suggests that efficiency-seeking business management reforms are not likely to generate sufficient resources to cover a budget decline. Instead, management reform should be sustained for reasons of stewardship and accountability. [source] Inventor bricolage and firm technology research and developmentR & D MANAGEMENT, Issue 5 2009Preeta M. Banerjee We examine the conditions around firm use of ,inventor bricolage,' or the reconstruction of technological capabilities through reallocation of extant individual inventors to address new opportunities embodied in patents. Empirically, we examine the dynamics of both firm and individual patenting activity in publicly traded Life Science Diagnostic firms to explore how inventor bricolage is related to firms' existing research and development (R&D) capabilities and firms' acquisition of external capabilities through merger and acquisition (M&A) activities. Evidence at the firm level suggests that breadth of inventors' human capital and collaboration with co-researchers with relevant experience is positively related to inventor bricolage. At the inventor level, the fewer patents an inventor has, the broader the individual's prior patent portfolio, and the more co-researchers with relevant experience, the more likely inventors will patent in a new area. M&A does not appear to have an impact on the utilization of existing human capital. Our findings suggest that R&D managers should assign inventors with less assimilative capacity and more creative capacity in teams where there is relevant experience in order to promote inventor bricolage. [source] WHY DID JAPAN'S TFP GROWTH SLOW DOWN IN THE LOST DECADE?THE JAPANESE ECONOMIC REVIEW, Issue 2 2006AN EMPIRICAL ANALYSIS BASED ON FIRM-LEVEL DATA OF MANUFACTURING FIRMS This study analyses the cause of the slowdown in Japan's TFP growth during the 1990s. Many preceding studies, examining the issue at the macro- or industry-level, have found that the slowdown was primarily due to the stagnation in TFP growth in the manufacturing sector. Using firm level panel data covering the entire sector, we investigate the causes of the TFP slowdown and find that the reallocation of resources from less efficient to more efficient firms was very slow and limited. This "low metabolism" seems to be an important cause for the slowdown in Japan's TFP growth. [source] HOW THE GLOBALIZATION OF R&D COMPETITION AFFECTS TRADE AND GROWTHTHE JAPANESE ECONOMIC REVIEW, Issue 3 2004GWANGHOON LEE The implications of international R&D competition on trade and growth are investigated. The model is one in which a separate R&D sector competes with the manufacturing sector to secure human capital, and technology is licensed to manufacturers by the winner of a pre-emptive R&D competition. The results show that globalization of R&D competition leads to trade between countries (even identical countries), because the result of competition leads to a reallocation of human capital between sectors. The winning country exports technology and traditional goods, while the loser exports manufactured goods. Globalization with indiscriminate technology licensing increases the world's economic growth rate. [source] | ||||||||||||||||||||||||||||||||||||||||