Teen Smoking and Birth Outcomes

In the U.S. teen mothers are more likely to give birth to low birth weight babies than non-teen mothers. There is also substantial evidence that smoking is a risk factor correlated with low birth weight. Low birth weight is a costly outcome in both the short and long term for parents, children, and society at large. This paper examines the causal link between teen age smoking behavior and low birth weight. We use a variety of empirical techniques including fixed effects and a matching estimator to identify the impact of smoking on babies of teen and non-teen mothers. We find that both OLS and matching estimator results yield large impacts of smoking on birth weight for teens and adults. However, when we control for unobservables through a fixed effects model, the impact of smoking on birth weight is diminished and there are relatively small differences in the impact of smoking on birth weight between teens and non-teens.

An Analysis of Private School Closings

We add to the small literature on private school supply by exploring exits of K-12 private schools. We find that the closure of private schools is not an infrequent event, and use national survey data from the National Center for Education Statistics to study closures of private schools. We assume that the probability of an exit is a function of excess supply of private schools over the demand, as well as the school's characteristics such as age, size, and religious affiliation. Our empirical results generally support the implications of the model. Working Paper 07-0

Perspectives of Pre-Service and In-Service Special Education Teachers About Homework Interventions

This purpose of this study was to integrate the research on empirically supported strategies for improving homework with the perspectives and attitudes of teachers who are expected to implement such strategies. Primary focus was on gathering and summarizing descriptive statistics of the types of interventions used for specific student populations throughout K-12 education. Data were obtained from graduate students enrolled in the Special Education program at Minnesota State University. Participants were asked to specify the types of homework support strategies they have implemented and indicate those students they think will benefit most from the particular strategies. Finally, participants were asked about their willingness to implement different strategies and their estimates of both the feasibility and barriers to implementation. It is hypothesized that only a subset of empirically supported strategies will be considered for use by in-service teachers. Also, it is expected that different strategies will be judged to be applicable to different grade levels of students requiring accommodations (e.g., kindergarten through fifth grade versus sixth through eighth grade versus high school students). Providing a list of commonly implemented strategies for homework problems will help teachers and other educational professionals incorporate standard practice concepts with best practice

Scarless skin repair in immunodeficient mice

Ohmic heating has been shown to increase the extraction yields of sucrose from sugar beets, apple juice from apples, beet dye from beet root, and soymilk from soybeans. Rice bran is a byproduct of the rice milling process that has economic potential by virtue of highly nutritious rice bran oil contained within the bran. In this study, ohmic heating was used to stabilize rice bran and to improve rice bran oil extraction yield as compared to microwave heating and a control (no heating). Results showed that ohmic heating is an effective method for rice bran stabilization with moisture addition. Free fatty acid concentration increased more slowly than the control for raw bran samples subjected to ohmic heating with no corresponding temperature rise, indicating that electricity has a non-thermal effect on lipase activity. Ohmic heating increased the total percent of lipids extracted from rice bran to a maximum of 92%, while 53% of total lipids were extracted from the control samples. Lowering the frequency of alternating current significantly increased the amount of oil extracted, probably due to electroporation. Ohmic heating was successfully applied to rice bran despite its high oil content. This could have important implications for the enhanced extraction of non-polar constituents

The Efficacy of Ultraviolet Radiation for Sterilizing Tools Used for Surgically Implanting Transmitters into Fish

Telemetry is frequently used to examine the behavior of fish, and the transmitters used are normally surgically implanted into the coelom of fish. Implantation requires the use of surgical tools such as scalpels, forceps, needle holders, and sutures. When several fish are implanted consecutively for large telemetry studies, it is common for surgical tools to be sterilized or, at minimum, disinfected between each use so that pathogens that may be present are not spread among fish. However, autoclaving tools can take a long period of time, and chemical sterilants or disinfectants can be harmful to both humans and fish and have varied effectiveness. Ultraviolet (UV) radiation is commonly used to disinfect water in aquaculture facilities. However, this technology has not been widely used to sterilize tools for surgical implantation of transmitters in fish. To determine its efficacy for this application, Pacific Northwest National Laboratory researchers used UV radiation to disinfect surgical tools (i.e., forceps, needle holder, stab scalpel, and suture) that were exposed to one of four aquatic organisms that typically lead to negative health issues for salmonids. These organisms included Aeromonas salmonicida, Flavobacterium psychrophilum, Renibacterium salmoninarum, and Saprolegnia parasitica. Surgical tools were exposed to the bacteria by dipping them into a confluent suspension of three varying concentrations (i.e., low, medium, high). After exposure to the bacterial culture, tools were placed into a mobile Millipore UV sterilization apparatus. The tools were then exposed for three different time periods—2, 5, or 15 min. S. parasitica, a water mold, was tested using an agar plate method and forceps-pinch method. UV light exposures of 5 and 15 min were effective at killing all four organisms. UV light was also effective at killing Geobacillus stearothermophilus, the organism used as a biological indicator to verify effectiveness of steam sterilizers. These techniques appear to provide a quick alternative disinfection technique for some surgical tools that is less harmful to both humans and fish while not producing chemical waste. However, we do not recommend using these methods with tools that have overlapping parts or other structures that cannot be directly exposed to UV light such as needle holders