Teenage Childbearing and Its Life Cycle Consequences: Exploiting a Natural Experiment

In this paper, we exploit a 'natural experiment' associated with human reproduction to identify the effect of teen childbearing on subsequent educational attainment, family structure, labor market outcomes and financial self-sufficiency. In particular, we exploit the fact that a substantial fraction of women who become pregnant experience a miscarriage (spontaneous abortion) and thus do not have a birth. If miscarriages were purely random and if miscarriages were the only way, other than by live births, that a pregnancy ended, then women, who had a miscarriage as a teen, would constitute an ideal control group with which to contrast teenage mothers. Exploiting this natural experiment, we devise an Instrumental Variables (IV) estimators for the consequences of teen mothers not delaying their childbearing, using data from the National Longitudinal Survey of Youth, 1979 (NLSY79). Our major finding is that many of the negative consequences of not delaying childbearing until adulthood are much smaller than has been estimated in previous studies. While we do find adverse consequences of teenage childbearing immediately following a teen mother's first birth, these negative consequences appear short- lived. By the time a teen mother reachers her late twenties, she appears to have only slightly more children, is only slightly more likely to be single mother, and has no lower levels of educational attainment than if she had delayed her childbearing to adulthood. In fact, by this age teen mothers appear to be better off in some aspects of their lives. Teenage childbearing appears to raise levels of labor supply, accumulated work experience and labor market earnings and appears to reduce the chances of living in poverty and participating in the associated social welfare programs. These estimated effects imply that the cost of teenage childbearing to U.S. taxpayers is negligible. In particular, our estimates imply that the widely held view that teenage childbearing imposes a substantial cost on government is an artifact of the failure to appropriately account for pre- existing socioeconomic differences between teen mothers and other women when estimating the causal effects of early childbearing. While teen mothers are very likely to live in poverty and experience other forms of adversity, our results imply that little of this would be changed just by getting teen mothers to delay their childbearing into adulthood.

BIASED BIASED TECHNOLOGICAL PROGRESS IN THE U.S. FARM SECTOR: A STRUCTURAL PERSPECTIVE

Research and Development/Tech Change/Emerging Technologies,

The Three Component Electronic Structure of the Cuprates Derived from SI-STM

We present a phenomenological model that describes the low energy electronic structure of the cuprate high temperature superconductor Bi2Sr2CaCu2O8+x as observed by Spectroscopic Imagining Scanning Tunneling Microscopy (SI-STM). Our model is based on observations from Quasiparticle Interference (QPI) measurements and Local Density of States (LDOS) measurements that span a range of hole densities from critical doping, p~0.19, to extremely underdoped, p~0.06. The model presented below unifies the spectral density of states observed in QPI studies with that of the LDOS. In unifying these two separate measurements, we find that the previously reported phenomena, the Bogoliubov QPI termination, the checkerboard conductance modulations, and the pseudogap are associated with unique energy scales that have features present in both the q-space and LDOS(E) data sets

Acute bronchitis in Australian general practice - a prescription too far?

OBJECTIVE: To quantify how frequently general practitioners in Australia prescribe antibiotics for acute bronchitis, which antibiotics are used, and whether there are subgroups of patients who might benefit from their use. DESIGN AND SETTING: A retrospective descriptive study using 3 sets of data: Australian Sentinel Practice Research Network, the Bettering the Evaluation and Care of Health (BEACH) Program, and the General Practice Research Network (GPRN). RESULTS: Over 50% of all patients with ‘acute bronchitis’ had either chest or one or more systemic signs on physical examination. The rate of antibiotic prescribing for acute bronchitis was 79.6% of acute bronchitis visits using BEACH data 2001–2002 and varied from 68.6 (95% CI: 62.8–74.5%) in 2001 to 78.7 (95% CI: 72.2–85.2%) in 1999 using GPRN data. Penicillins, followed by macrolides, were the most commonly prescribed antibiotics. DISCUSSION: Australian GPs frequently prescribe antibiotics for ‘acute bronchitis’ despite guidelines to the contrary. One reason may be that many patients present with chest or systemic signs.N.P. Stocks, H. McElroy, G.P. Sayer and K. Duszynsk

Anti-phase Modulation of Electron- and Hole-like States in Vortex Core of Bi2Sr2CaCu2Ox Probed by Scanning Tunneling Spectroscopy

In the vortex core of slightly overdoped Bi2Sr2CaCu2Ox, the electron-like and hole-like states have been found to exhibit spatial modulations in anti-phase with each other along the Cu-O bonding direction. Some kind of one-dimensionality has been observed in the vortex core, and it is more clearly seen in differential conductance maps at lower biases below +-9 mV