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Background Studies of early-term birth after demonstrated fetal lung maturity show that respiratory and other outcomes are worse with early-term birth (370–386 weeks) even after demonstrated fetal lung maturity when compared with full-term birth (390–406 weeks). However, these studies included medically indicated births and are therefore potentially limited by confounding by the indication for delivery. Thus, the increase in adverse outcomes might be due to the indication for early-term birth rather than the early-term birth itself. Objective We examined the prevalence and risks of adverse neonatal outcomes associated with early-term birth after confirmed fetal lung maturity as compared with full-term birth in the absence of indications for early delivery. Study Design This is a secondary analysis of an observational study of births to 115,502 women in 25 hospitals in the United States from 2008 through 2011. Singleton nonanomalous births at 37–40 weeks with no identifiable indication for delivery were included; early-term births after positive fetal lung maturity testing were compared with full-term births. The primary outcome was a composite of death, ventilator for ≥2 days, continuous positive airway pressure, proven sepsis, pneumonia or meningitis, treated hypoglycemia, hyperbilirubinemia (phototherapy), and 5-minute Apgar Results In all, 48,137 births met inclusion criteria; the prevalence of fetal lung maturity testing in the absence of medical or obstetric indications for early delivery was 0.52% (n = 249). There were 180 (0.37%) early-term births after confirmed pulmonary maturity and 47,957 full-term births. Women in the former group were more likely to be non-Hispanic white, smoke, have received antenatal steroids, have induction, and have a cesarean. Risks of the composite (16.1% vs 5.4%; adjusted odds ratio, 3.2; 95% confidence interval, 2.1–4.8 from logistic regression) were more frequent with elective early-term birth. Propensity scores matching confirmed the increased primary composite in elective early-term births: adjusted odds ratios, 4.3 (95% confidence interval, 1.8–10.5) for 1:1 and 3.5 (95% confidence interval, 1.8–6.5) for 1:2 matching. Among components of the primary outcome, CPAP use and hyperbilirubinemia requiring phototherapy were significantly increased. Transient tachypnea of the newborn, neonatal intensive care unit admission, and prolonged neonatal intensive care unit stay (>2 days) were also increased with early-term birth. Conclusion Even with confirmed pulmonary maturity, early-term birth in the absence of medical or obstetric indications is associated with worse neonatal respiratory and hepatic outcomes compared with full-term birth, suggesting relative immaturity of these organ systems in early-term births.

We find that trading volume increases and market liquidity remains unchanged, while the adverse selection and order-processing cost components of the spread increase and decrease, respectively, after margin levels decline when stocks become margin-eligible. This evidence indicates that the information content of trades has increased, thereby improving market quality. However, no changes were detected after the 1997 regulatory reforms. These results have implications across a broad swath of corporate finance dimensions, including the (1) cost of capital, (2) public vs. private financing decision, (3) form of managerial compensation, (4) type of ownership structure, and (5) degree of shareholder monitoring.

An excitation and optical extraction geometry suitable for compact high power gas lasers is described. Multiple slab discharges are established in a diffusion-cooled radial electrode array. Each gain channel is independently driven from a common RF source via a resonant-cavity power distribution system. Radial excitation augmented with multi-channel self-injection phase locking provides stable optical power extraction at good efficiency. The concept is easily scalable to very high powers while dramatically reducing unit size and cost.

We examine a sample of 5896 stocks listed on Nasdaq between 1974 and 1988 to see whether the price per share has significant statistical power in forecasting subsequent returns and attrition rates. Consistent with anecdotal evidence, we document a higher mortality rate for lower-priced stocks than for higher-priced issues. Surprisingly, mortality is not related to market capitalization. Our results also hold for subsamples partitioned by industry and issue year. On average, investors are not adequately compensated for this additional mortality risk, earning lower risk-adjusted rates of return on portfolios of lower-priced shares than on portfolios of higher-priced shares.

A unique way of driving a multi-channel RF excited slab laser is presented. Resonant cavity techniques are employed to provide high power splitting and impedance transformation. Uniform and isolated power division was observed in eight discharge channels, stacked in a radial array, referred to as the Zodiac geometry. Impedance matching networks were not necessary as the RF cavity splitter creates a near ideal voltage source capable of driving any impedance. With 8 out of the 24 electrodes driven in the radial array, optical powers in excess of 1.2 kW have been observed at efficiencies of 12%.

This paper studies expectations of capital appreciation in the housing market. We show that expectations impounded in the rent/price ratio at the beginning of the decade successfully predict appreciation rates, but only if we first control for cross-sectional differences in the quality of rental versus owner-occupied housing. We also demonstrate that observed rent/price ratios contain a disequilibrium component that also has power to forecast subsequent appreciation rates. Finally, we provide evidence consistent with euphoria: participants in housing markets appear to overreact to income growth.

We investigate the relations between trading volumes and our proxies for information flows and divergences in opinions. We view S&P 500 Index futures' open interest as a useful proxy for divergences of traders' opinions, and find that volumes are higher on days when open interest increases than on days with declines. Volume in individual equities is more closely related to firm-specific information flows, while equity basket volume is more closely associated with market information. This differential impact is greatest for small capitalization stocks where market-wide news has no explanatory power.

Background Cesarean delivery in the second stage of labor is common, whereas the frequency of operative vaginal delivery has been declining. However, data comparing outcomes for attempted operative vaginal delivery vs cesarean in the second stage are scant. Previous studies that examine operative vaginal delivery have compared it to a baseline risk of complications from a spontaneous vaginal delivery and cesarean delivery. However, when a woman has a need for intervention in the second stage, spontaneous vaginal delivery is not an option she or the provider can choose. Thus, the appropriate clinical comparison is cesarean vs operative vaginal delivery. Objective Our objective was to compare outcomes by the first attempted operative delivery (vacuum, forceps vs cesarean delivery) in patients needing second-stage assistance at a fetal station of +2 or below. Study Design We conducted secondary analysis of an observational obstetric cohort in 25 academically affiliated US hospitals over a 3-year period. A subset of ≥37 weeks, nonanomalous, vertex, singletons, with no prior vaginal delivery who reached a station of +2 or below and underwent an attempt at an operative delivery were included. Indications included for operative delivery were: failure to descend, nonreassuring fetal status, labor dystocia, or maternal exhaustion. The primary outcomes included a composite neonatal outcome (death, fracture, length of stay ≥3 days beyond mother's, low Apgar, subgaleal hemorrhage, ventilator support, hypoxic encephalopathy, brachial plexus injury, facial nerve palsy) and individual maternal outcomes (postpartum hemorrhage, third- and fourth-degree tears [severe lacerations], and postpartum infection). Outcomes were examined by the 3 attempted modes of delivery. Odds ratios (OR) were calculated for primary outcomes adjusting for confounders. Final mode of delivery was quantified. Results In all, 2531 women met inclusion criteria. No difference in the neonatal composite outcome was observed between groups. Vacuum attempt was associated with the lowest frequency of maternal complications (postpartum infection 0.2% vs 0.9% forceps vs 5.3% cesarean, postpartum hemorrhage 1.4% vs 2.8% forceps vs 3.8% cesarean), except for severe lacerations (19.1% vs 33.8% forceps vs 0% cesarean). When confounders were taken into account, both forceps (OR, 0.16; 95% confidence interval, 0.05–0.49) and vacuum (OR, 0.04; 95% confidence interval, 0.01–0.17) were associated with a significantly lower odds of postpartum infection. The neonatal composite and postpartum hemorrhage were not significantly different between modes of attempted delivery. Cesarean occurred in 6.4% and 4.4% of attempted vacuum and forceps groups ( P = .04). Conclusion In patients needing second-stage delivery assistance with a station of +2 or below, attempted operative vaginal delivery was associated with a lower frequency of postpartum infection, but higher frequency of severe lacerations.

This study examines price stabilization in new equity issues. Stabilizationtruncates the distribution of post-issue prices at a floor price, lowering the risk of adverse price moves and hence, in a competitive dealer market, reducing the bid-ask spread. Using 1.523 NASDAO-traded firm- commitment initial public offerings issued between 1982 and 1987, we find that spreads narrow when the market price is close to the offer price and stabilization is most likely. Moreover, significant negative returns are documented after the hypothesized termination of stabilizing activities, suggesting that stabilization, and its cessation, affect market prices.

A limiting feature in high-power laser technology which has surfaced in recent years is alignment instability induced by thermally generated distortions of the optical hardware and phase perturbations of the gain media under elevated power loading. In an effort to ameliorate these problems, a study was initiated to ascertain the feasibility of utilizing a feedback control system both to monitor and align the resonator optics of a multikilowatt laser; thereby actively preserving optimum mode quality. This papers summarizes the results of this project and outlines the basic approach used to construct a controller which accomplishes fully automatic alignment of both mirrors in an unstable resonator for a 20 kW CO2 machine. A mathematical model of the control system is presented along with a description of the principles of operation. Data are provided to document the major improvement in device performance achievable using this automatic alignment controller concept.

The valence region electronic structure of Ln(acac) 3 complexes (Ln = Nd, Tm, Pr; acac = acetylacetonate) is investigated using, principally, gas-phase ultraviolet photoelectron (PE) spectroscopy. Analysis of PE spectra focuses on the 7–12 eV region containing the first several ionization bands which likely contain metal f-ionizations and acac-based ionizations. These correspond to oxygen 2p-type orbitals and carbon 2p-type orbitals, which are equivalent to oxygen lone pairs and electrons from the pi-bond system of the ligand.

Experimental results on a unique multi-channel slot-type CO 2 laser system fitted with a toric unstable resonator are presented. The discharge structure combines both large-area and multi-beam laser array concepts into a single, compact package. The unstable toric resonator has the unique property that optical radiation is extracted from the center of the system. Experiments have indicated that output beam characteristics are a function of the coupling aperture in the secondary mirror. Output power levels of 35 W per channel in a near diffraction limited beam have been obtained with 10% power conversion efficiency.

This study examines additions of OTC issues to the list of marginable securities and tests the hypothesis that margin trading destabilizes prices and contributes to volatility. No detrimental effects are found. Instead, evidence suggests that margin eligibility increases the flow of information and enhances depth. Though volumes are 30% larger, volatility and noise decrease with the inception of margin trading. Further, margin eligibility is valuable: increases in value of 2% occur upon the announcement of eligibility. Analysis of a small sample of margin eligibility revocations provides no evidence that tightening margin restrictions reduces volatility.

A computer vision system which performs real-time mode control of a high powered CO 2 laser has been developed. The device continuously monitors the output beam to derive alignment data for the primary resonator optic. The technique ensures that the laser's intensity distribution is as uniform as possible. Valuable profile data and beam diagnostics are also generated by the system.

We investigate IPO market efficiency using a sample of equity carve-outs offered during the period of 1985–2005. Unlike IPOs examined in previous studies where trading during the pre-IPO book-building period does not exist and trading on the IPO date is rationed, in equity carve-outs, investors can trade in the non-rationed market for shares of the parent, which holds a significant fraction of the subsidiary. We find that the subsidiary's initial day return is significantly related to its parent's return over the book-building period, but unrelated to its parent's contemporaneous return. Neither the pre-IPO price revision of the subsidiary nor the return to the parent on the initial trading day can be predicted. While the portion of the subsidiary's initial return unpredictable from information available during the book-building period is significantly related to its parent's contemporaneous return, the predictable component of the initial return is not. We interpret these results as evidence consistent with market efficiency.

In this study, we trace the impact of corporate focus by estimating the relationships of focus with cash flow and firm value. In contrast to past studies that examine the effects of diversifying across SIC code defined industries, we show, using Tobin's q, that diversification even within a single industry negatively affects value. Our evidence indicates that this value reduction is not due to poor managerial performance. Project level cash flows are actually higher for less focused firms. However, these gains are exactly offset by higher management, administrative and interest expenses. Thus the corporate cash flows available to shareholders are not related to focus. Finally, we provide empirical evidence that links the effect of focus on value to informational asymmetries which cause the equity of diversified firms to be less liquid.

The inhibitory reflex evoked in single motor units in human masseter by lip stimulation was recorded at several joint angles. The pre-stimulus firing frequency of the unit was kept constant. Some modulation of the inhibitory response at different vertical jaw positions (i.e., temporomandibular joint angle) was observed in most masseter units, with the majority of the modulated units being inhibited less when the teeth were closer together.

Measurements of the electron density within an axial CO 2 laser discharge subjected to a transverse rotating magnetic field are presented. Experiments were performed with a single Langmuir probe. Electron density is evaluated using Su and lam's thick sheath expression for a stationary plasma. Results are presented for a 2.7 kPa (20 torr) discharge with external pre-ionization and for a 0.7 kPa (5 torr) self-sustained discharge.