Kelu-1 is a Binary L Dwarf: First Brown Dwarf Science from Laser Guide Star Adaptive Optics

(Abridged) We present near-IR imaging of the nearby L dwarf Kelu-1 obtained with the Keck sodium laser guide star adaptive optics (LGS AO) system as part of a high angular resolution survey for substellar binaries. Kelu-1 was one of the first free-floating L dwarfs identified, and the origin of its overluminosity compared to other similar objects has been a long-standing question. Our images clearly resolve Kelu-1 into a 0.29'' (5.4 AU) binary, and a previous non-detection by HST demonstrates that the system is a true physical pair. Binarity explains the properties of Kelu-1 that were previously noted to be anomalous compared to other early-L dwarfs. We estimate spectral types of L1.5-L3 and L3-L4.5 for the two components, giving model-derived masses of 0.05-0.07 Msun and 0.045-0.065 Msun for an estimated age of 0.3-0.8 Gyr. More distant companions are not detected to a limit of 5-9 Mjup. The presence of lithium absorption indicates that both components are substellar, but the weakness of this feature relative to other L dwarfs can be explained if only Kelu-1B is Li-bearing. Determining whether both or only one of the components possesses lithium could constrain the age of Kelu-1 (and other Li-bearing L binaries) with higher precision than is possible for most ultracool field objects. These results are the first LGS AO observations of brown dwarfs and demonstrate the potential of this new instrumental capability for substellar astronomy.Comment: 24 pages, Astrophysical Journal, in press (Nov 20, 2005 issue). Note that Figure 1 of the PDF version is degraded by arxiv.org, but the Postscript version is fine. Version 2 includes very minor changes to match the published versio

Studying the Child Obesity Epidemic with Natural Experiments

We utilize clinical records of successive visits by children to pediatric clinics in Indianapolis to estimate the effects on their body mass of environmental changes near their homes. We compare results for fixed-residence children with those for cross-sectional data. Our environmental factors are fast food restaurants, supermarkets, parks, trails, and violent crimes, and 13 types of recreational amenities derived from the interpretation of annual aerial photographs. We looked for responses to these factors changing within buffers of 0.1, 0.25, 0.5, and 1 mile. We found that cross-sectional estimates are quite different from the Fixed Effects estimates of the impacts of amenities locating near a child. In cross section nearby fast food restaurants were associated with higher BMI and supermarkets with lower BMI. These results were reversed in the FE estimates. The recreational amenities that appear to lower children's BMI were fitness areas, kickball diamonds, and volleyball courts. We estimated that locating these amenities near their homes could reduce the weight of an overweight eight-year old boy by 3 to 6 pounds

Postpartum Psychosis: A Legitimate Defense for Negating Criminal Responsibility (Comment)

Part I traces the slaughter of children throughout history and literature, and reveals the functions and reasons behind the ancient practice of infanticide. Part II discusses the medical debate regarding the causes of postpartum psychosis. Part III evaluates the legal recognition of postpartum psychosis as a defense in terms of usage and success rates. Analyzing postpartum depression to determine whether it meets the legal test of insanity, it compares the English common law to the American perspective of infanticide. Four tests are examined in detail: the M'Naghten test, the American Law Institute Model Penal Code test, the "Irresistible Impulse" test, and the Durham or "Product" test. Part IV looks to the effects of gender on sentencing, and compares sentencing for maternal as opposed to paternal infanticides. It examines how mothers are punished under the Texas justice system. Postpartum psychosis is a gender-specific defense. Part IV determines whether gender is a relevant factor in the charge of murder, and examines the validity of postpartum psychosis as an "Excuse" defense, along with the partial defense of "Extreme Mental and Emotional Disturbance." Evaluating current Congressional bills regarding postpartum disorders, Part IV also addresses the Texas approach to postpartum psychosis, as related to mental illness through the Texas Mental Health Code and the Texas Penal Code. Part V advocates proposed approaches to the defense of postpartum psychosis by either changing the burden of proof or considering such a defense as a mitigating factor at sentencing, if not both; it advocates the possibility of manslaughter for infanticide and involuntary manslaughter for neonaticide. Lastly, the Texas Penal Code and proposed amendments are analyzed and compared to the "guilty but mentally ill" standard' of other states, as well as the Model Penal Code. Part V ultimately looks to various statutes-state, federal, and foreign-for possible answers to the puzzle of postpartum psychosis in Texas courts today

Pathways: Augmenting interoperability across scholarly repositories

In the emerging eScience environment, repositories of papers, datasets, software, etc., should be the foundation of a global and natively-digital scholarly communications system. The current infrastructure falls far short of this goal. Cross-repository interoperability must be augmented to support the many workflows and value-chains involved in scholarly communication. This will not be achieved through the promotion of single repository architecture or content representation, but instead requires an interoperability framework to connect the many heterogeneous systems that will exist. We present a simple data model and service architecture that augments repository interoperability to enable scholarly value-chains to be implemented. We describe an experiment that demonstrates how the proposed infrastructure can be deployed to implement the workflow involved in the creation of an overlay journal over several different repository systems (Fedora, aDORe, DSpace and arXiv).Comment: 18 pages. Accepted for International Journal on Digital Libraries special issue on Digital Libraries and eScienc

Noise reducing screen devices for in-flow pressure sensors

An acoustic sensor assembly is provided for sensing acoustic signals in a moving fluid such as high speed fluid stream. The assembly includes one or more acoustic sensors and a porous, acoustically transparent screen supported between the moving fluid stream and the sensor and having a major surface disposed so as to be tangent to the moving fluid. A layer of reduced velocity fluid separating the sensor from the porous screen. This reduced velocity fluid can comprise substantially still air. A foam filler material attenuates acoustic signals arriving at the assembly from other than a predetermined range of incident angles