Diffraction Analysis of 2-D Pupil Mapping for High-Contrast Imaging

Pupil-mapping is a technique whereby a uniformly-illuminated input pupil, such as from starlight, can be mapped into a non-uniformly illuminated exit pupil, such that the image formed from this pupil will have suppressed sidelobes, many orders of magnitude weaker than classical Airy ring intensities. Pupil mapping is therefore a candidate technique for coronagraphic imaging of extrasolar planets around nearby stars. Unlike most other high-contrast imaging techniques, pupil mapping is lossless and preserves the full angular resolution of the collecting telescope. So, it could possibly give the highest signal-to-noise ratio of any proposed single-telescope system for detecting extrasolar planets. Prior analyses based on pupil-to-pupil ray-tracing indicate that a planet fainter than 10^{-10} times its parent star, and as close as about 2 lambda/D, should be detectable. In this paper, we describe the results of careful diffraction analysis of pupil mapping systems. These results reveal a serious unresolved issue. Namely, high-contrast pupil mappings distribute light from very near the edge of the first pupil to a broad area of the second pupil and this dramatically amplifies diffraction-based edge effects resulting in a limiting attainable contrast of about 10^{-5}. We hope that by identifying this problem others will provide a solution.Comment: 23 pages, 13 figures, also posted to http://www.orfe.princeton.edu/~rvdb/tex/piaaFresnel/ms.pd

Depression as a risk factor for adverse outcomes in coronary heart disease

BACKGROUND: Depression is firmly established as an independent predictor of mortality and cardiac morbidity in patients with coronary heart disease (CHD). However, it has been difficult to determine whether it is a causal risk factor, and whether treatment of depression can improve cardiac outcomes. In addition, research on biobehavioral mechanisms has not yet produced a definitive causal model of the relationship between depression and cardiac outcomes. DISCUSSION: Key challenges in this line of research concern the measurement of depression, the definition and relevance of certain subtypes of depression, the temporal relationship between depression and CHD, underlying biobehavioral mechanisms, and depression treatment efficacy. SUMMARY: This article examines some of the methodological challenges that will have to be overcome in order to determine whether depression should be regarded as a key target of secondary prevention in CHD

Population Size Structure and Feeding Biology of Bathynerita naticoidea Clarke 1989 (Gastropoda: Neritacea) from Gulf of Mexico Hydrocarbon Seeps

Bathynerita naticoidea is a numerically dominant gastropod in upper continental slope chemosynthetic communities of the northern Gulf of Mexico. A comparison of population size structure at four sites off Louisiana revealed site-specific differences in mean shell size consistent with different recruitment histories and growth rates. Where individuals grow to the largest size, population numbers are low and recruitment seems to be limited. Where individuals grow to the smallest size, populations are high and recruitment seems to be high. These patterns appear to parallel the population size pattern of the beds of Bathymodiolus childressi Gustafson et. al. 1998 inhabited by the snail, which suggests a link between the control of the two. Analysis of gut contents and fecal matter of B. naticoidea and the organic film on the shell surface of B. childressi confirmed initial assumptions that the snail feeds by radular browsing. Free-living bacteria are abundant on mussel surfaces and are ingested by the snail. The presence of bacteria in the gut and feces was, however, lower, possibly because of dilution by mucus and digestion. It is proposed that B. childressi provides more than a passive surface for organic film development. The mussel may control the organic film development, thus controlling availability of food to the snail

Spin Trapping Compounds

Compositions containing as the active ingredient a spin-trapping reagent, preferably α-phenyl butyl nitrone (PBN) or spin-trapping derivatives thereof, in a suitable pharmaceutical carrier for administration to a patient are disclosed for treating or preventing symptoms associated with aging or other conditions associated with oxidative tissue damage. Other spin-trapping agents can also be used, such as 5,5-dimethyl pyrroline N-oxide (DMPO) or α-(4-pyridyl 1-oxide)-N-tert-butylnitrone (POBN), and other spin-trapping derivatives thereof. These compositions and methods are useful in the treatment of age-related disorders, pre-surgical and/or pre-anesthetic preparation or administration of chemotherapeutic agents, and in the treatment of disorders or trauma of the brain, cardiovascular system, and lymphatic system. Studies in animals demonstrate that administration of compound for a two week period reduces the level of oxidized brain enzymes to normal and restores memory to the same level as tested in young control animals

Spin Trapping Pharmaceutical Compositions and Methods for Use Thereof

Spin trapping compositions in general have now been discovered to be effective in treating a variety of disorders, including disorders such as those arising from ischemia, infection, inflammation, exposure to radiation or cytotoxic compounds, not just of the central and peripheral nervous systems but of peripheral organ disease having a wide variety of etiologies. In the preferred embodiment, the compositions for treating tissue damage from ischemia contain PBN, or active derivatives thereof, in a suitable pharmaceutical carrier for intravenous, oral, topical, or nasal/pulmonary administration. Many different disorders can be treated using these compounds, including diseases or disorders of the central and peripheral nervous systems, and disorders arising from ischemia, infection, inflammation, oxidation from exposure to radiation or cytotoxic compounds, as well as due to naturally occurring processes such as aging

Phenylbutyl Nitrone Compositions and Methods for Prevention of Gastric Ulceration

Compositions containing PBN, or active derivatives thereof, in a suitable pharmaceutical carrier for administration to a patient, are disclosed for treating or preventing gastric ulceration caused by ingestion of non-steroidal anti-inflammatories. Based on animal studies, the dosage is in the range of 3 to 300 mg/kg and is administered prior to, simultaneously, or shortly after ingestion of the NSAID compounds(s). In the preferred embodiment, the range is between 10 and 30 mg/kg, depending on the dosage unit required to protect the mucosa. The preferred method of administration is orally, alone or in combination with the non-steroidal anti-inflammatory. It is believed that the PBN is also useful alone for treatment or prevention of ulcers, aspects of diarrhea, gastritis, esophagitis, ileitis, and as an analgesic

PBN, DMPO, and POBN Compositions and Method of Use Thereof for Inhibition of Age-Associated Oxidation

Compositions containing as the active ingredient a spin-trapping reagent, preferably α-phenyl butyl nitrone (PBN) or spin-trapping derivatives thereof, in a suitable pharmaceutical carrier for administration to a patient are disclosed for treating or preventin symptoms associated with aging or other conditions associated with oxidative tissue damage. Other spin-trapping agents can also be used, such as 5,5-dimethyl pyrroline N-oxide (DMPO) or α-(4-pyridyl 1-oxide)-N-tert-butylnitrone (POBN), and other spin-trapping derivatives thereof. These compositions and methods are useful in the treatment of age-related disorders, pre-surgical and/or pre-anesthetic preparation or administration of chemotherapeutic agents, and in the treatment of disorders or trauma of the brain, cardiovascular system, and lymphatic system. Studies in animals demonstrate that administration of compound for a two week period reduces the level of oxidized brain enzymes ot normal and restores memory to the sam level as tested in young control animals

Spin Trapping Pharmaceutical Compositions and Methods for Use Thereof

Spin trapping compositions in general have now been discovered to be effective in treating a variety of disorders, including disorders such as those arising from ischemia, infection, inflammation, exposure to radiation or cytotoxic compounds, not just of the central and peripheral nervous systems but of peripheral organ disease having a wide variety of etiologies. In the preferred embodiment, the compositions for treating tissue damage from ischemia contain PBN, or active derivatives thereof, in a suitable pharmaceutical carrier for intravenous, oral, topical, or nasal/pulmonary administration. Other preferred spin-trapping agents include 5,5-dimethyl pyrroline N-oxide (DMPO), α-(4-pyridyl-1-oxide)-N-tert-butylnitrone (POBN), and (TEMPO) and spin-trapping derivatives thereof. Examples of derivatives of PBN include halogenated derivatives, bifunctional derivatives, conjugates with drugs or targeting molecules, dimers and cyclodextran polymers of PBN. Many different disorders can be treated using these compounds, including diseases or disorders of the central and peripheral nervous systems, and disorders arising from ischemia, infection, inflammation, oxidation from exposure to radiation or cytotoxic compounds, as well as due to naturally occurring processes such as aging

Phenyl Butyl Nitrone Compositions and Methods for Treatment of Oxidative Tissue Damage

Compositions for treating tissue damage from ischemia contain PBN, or active derivatives thereof, which are active during ischemia in preventing ATP depletion of the cells which predisposes them to subsequent injury during reperfusion, and which are active during reperfusion as oxygen radical scavengers, in a suitable pharmaceutical carrier for systemic or local administration, especially to the CNS, spinal column and eyes. Based on animal studies, the dosage for treating damage due to stroke is in the range of 10 to 300 mg/kg. Similar dosages are useful in treating damage resulting from free radical generation during inflammation, either as a product of infection or exposure to inflammatory agents or abusive agents, including drugs and alcohol