A Dynamic Theory of China-U.S. Trade: Making Sense of the Imbalances

China’s trade surplus with the U.S. is now more than a quarter of the U.S. trade deficit and, with China growing faster than the U.S., raises questions about its future course. Some media commentators term the chronic trade surplus “mercantilist” but offer no persuasive motive for it. Academics taking the classical static view regard the trade surpluses as a policy error. We offer a rudimentary model in which trade surplus in the early years is central for an optimal growth trajectory. The novelty derives from two features of underdevelopment shaping trade between backward economies like China and advanced economies like the U.S. First, the initial comparative disadvantages in China are an artifact of the uneven technical advances made by the U.S., so China may be able to erase those disadvantages through technological transfers bought with surpluses of exports over imports in goods and services. Reserves may be accumulated to pay for large lumps of knowhow. Second, the diffusion of new products requires learning, which takes time, so the initial dearth of familiarity in China with a range of U.S. consumer goods operates as a drag on import demand for them, which may tip trade balances into surplus

European association of perinatal medicine (EAPM) position statement: Screening, diagnosis and management of congenital anomalies of the umbilical cord

Congenital anomalies of the umbilical cord are associated with an increased risk of pregnancy and perinatal complications. Some anomalies of the cord have a higher prevalence than other fetal structural anomalies. The most common anomalies are the absence of an umbilical artery and velamentous insertion of the cord (with or without vasa previa). These anomalies, even when not associated with fetal structural defects, increase the risk of adverse perinatal outcome including, fetal growth restriction and stillbirth. In the absence of prenatal diagnosis, vasa previa is associated with the highest perinatal morbidity and mortality of all congenital anomalies of the umbilical cord. Most cases can be detected by ultrasound from the beginning of the second trimester and should be included in the routine mid-pregnancy ultrasound examination. Documentation should include cord insertion site, number of vessels in the cord, and if other pathologies have been detected. Pregnancies at increased risk of velamentous cord insertion should be screened for vasa previa using transvaginal ultrasound and colour Doppler imaging. If a velamentous cord insertion or isolated single umbilical artery is detected, individualised follow-up during pregnancy and tailored obstetric management are indicated

Methane and carbon dioxide adsorption on edge-functionalized graphene: A comparative DFT study

With a view towards optimizing gas storage and separation in crystalline and disordered nanoporous carbon-based materials, we use ab initio density functional theory calculations to explore the effect of chemical functionalization on gas binding to exposed edges within model carbon nanostructures. We test the geometry, energetics, and charge distribution of in-plane and out-of-plane binding of CO2 and CH4 to model zigzag graphene nanoribbons edge-functionalized with COOH, OH, NH2, H2PO3, NO2, and CH3. Although different choices for the exchange-correlation functional lead to a spread of values for the binding energy, trends across the functional groups are largely preserved for each choice, as are the final orientations of the adsorbed gas molecules. We find binding of CO2 to exceed that of CH4 by roughly a factor of two. However, the two gases follow very similar trends with changes in the attached functional group, despite different molecular symmetries. Our results indicate that the presence of NH2, H2PO3, NO2, and COOH functional groups can significantly enhance gas binding with respect to a hydrogen-passivated edge, making the edges potentially viable binding sites in materials with high concentrations of edge carbons. To first order, in-plane binding strength correlates with the larger permanent and induced dipole moments on these groups. Implications for tailoring carbon structures for increased gas uptake and improved CO2/CH4 selectivity are discussed.Comment: 12 pages, 7 figure

Is Cerebroplacental Ratio A Marker of Impaired Fetal Growth Velocity and Adverse Pregnancy Outcome?

BACKGROUND: The cerebroplacental ratio has been proposed as a marker of failure to reach growth potential near term. Low cerebroplacental ratio, regardless of the fetal size, is independently associated with the need for operative delivery for presumed fetal compromise and with neonatal unit admission at term. OBJECTIVE: The main aim of this study was to evaluate whether the cerebroplacental ratio at term is a marker of reduced fetal growth rate. The secondary aim was to investigate the relationship between low cerebroplacental ratio at term, reduced fetal growth velocity and adverse pregnancy outcome. DESIGN: retrospective cohort study of singleton pregnancies in a tertiary referral center. The abdominal circumference was measured at 20-24 weeks' gestation, and both abdominal circumference and fetal Dopplers recorded at or beyond 35 weeks, within two weeks of delivery. Abdominal circumference and birthweight values were converted into Z scores and centiles, respectively, and fetal Doppler parameters into multiples of median, adjusting for gestational age. Abdominal circumference growth velocity was quantified using the difference in abdominal circumference Z score, comparing the scan at or beyond 35 weeks with the scan at 20-24 weeks. Both univariable and multivariable logistic regression analyses were performed to investigate the association between low cerebroplacental ratio, low abdominal circumference growth velocity (in the lowest decile), and to identify and adjust for potential confounders. As a sensitivity analysis, we refitted the model excluding the data on pregnancies with small for gestational age neonates. RESULTS: The study included 7944 pregnancies. Low cerebroplacental ratio multiples of median was significantly associated with both low abdominal circumference growth velocity (adjusted OR 2.10; 95%CI 1.71-2.57, p<0.001) and small for gestational age (adjusted OR 3.60; 95%CI 3.04-4.25, p<0.001). After the exclusion of pregnancies resulting in small for gestational age neonates, low cerebroplacental ratio multiples of median remained significantly associated with both low abdominal circumference growth velocity (adjusted OR 1.76; 95%CI 1.34-2.30, p<0.001) and birthweight centile (adjusted OR 0.99; 95%CI 0.998-0.995, p<0.001). The need for operative delivery for fetal compromise was significantly associated with low cerebroplacental ratio (adjusted OR 1.40; 95%CI 1.10-1.78, p=0.006), even after adjusting for both the umbilical artery pulsatility index multiples of median and middle cerebral artery pulsatility index multiples of median. The results were similar even after the exclusion of pregnancies resulting in small for gestational age neonates (adjusted OR 1.39; 95%CI 1.06-1.84, p=0.018). Low cerebroplacental ratio multiples of median remained significantly associated with the risk of operative delivery for presumed fetal compromise (p<0.001), even after adjusting for the known antenatal and intrapartum risk factors. These associations persisted even after exclusion of small for gestational age births. In appropriate for gestational age sized fetuses, abdominal circumference growth velocity was significantly lower in those with low cerebroplacental ratio multiples of median than in those with normal cerebroplacental ratio multiples of median (p<0.001). CONCLUSION: Cerebroplacental ratio is a marker of impaired fetal growth velocity and adverse pregnancy outcome, even in fetuses whose size is considered appropriate using conventional biometry

The theory of the firm and its critics: a stocktaking and assessment

Includes bibliographical references."Prepared for Jean-Michel Glachant and Eric Brousseau, eds. New Institutional Economics: A Textbook, Cambridge, Cambridge University Press.""This version: August 22, 2005."Since its emergence in the 1970s the modern economic or Coasian theory of the firm has been discussed and challenged by sociologists, heterodox economists, management scholars, and other critics. This chapter reviews and assesses these critiques, focusing on behavioral issues (bounded rationality and motivation), process (including path dependence and the selection argument), entrepreneurship, and the challenge from knowledge-based theories of the firm

Market Liquidity, Investor Participation and Managerial Autonomy: Why Do Firms Go Private?

We analyze a publicly-traded firm's decision to stay public or go private when managerial autonomy from shareholder intervention affects the supply of productive inputs by management. We show that both the advantage and the disadvantage of public ownership relative to private ownership lie in the liquidity of public ownership. While the liquidity of public ownership lets shareholders trade easily and supply capital at a lower cost, the liquidity-engendered trading also results in stochastic shocks to a firm's shareholder base. This exposes management to uncertainty regarding the identity of future shareholders and their extent of intervention in management decisions and in turn curtails managerial incentives. By contrast, because of its illiquidity, private ownership provides a stable shareholder base and improves these inputprovision incentives but results in a higher cost of capital. Thus, capital market liquidity, while being a principal advantage of public ownership, also has a surprising 'dark side' that discourages public ownership. Our model takes seriously a key difference between private and public equity markets in that, unlike the private market, the firm's shareholder base, namely the extent of investor participation, is stochastic in the public market. This allows us to extract predictions about the effects of investor participation on the stock price level and volatility and on the public firm's incentives to go private, thereby providing a link between investor participation and firm participation in public markets. Lesser investor participation induces lower and more volatile stock prices, encouraging public firms to go private, whereas greater investor participation encourages younger firms to go public. Moreover, IPO underpricing is optimal because it is shown to lead to a higher and less volatile post-IPO stock price, greater autonomy for the manager and a higher supply of privately-costly managerial inputs

Harvard Business Review on Entrepreneurship

v. 217 hal.;21 c