881 research outputs found

    Aircraft activity and sound levels relative to recreation opportunity spectrum settings in the Great Barrier Reef Marine Park a case study from Whitehaven Beach, Whitsunday Island 2003

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    Aircraft overflights and associated noise in National Parks is an environmental management issue which is becoming increasingly important as growth in the tourism industry occurs in Australia and world-wide. The protection of natural quiet is arguably as crucial as the protection of wildlife and clean water

    The Fate of Chemically Dispersed and Untreated Crude Oil in Arctic Benthic Biota

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    Subtidal benthic biota were monitored for petroleum hydrocarbons following two experimental oil spills at Cape Hatt, N.W.T., Canada. In one spill oil was chemically dispersed into the water column, and in the other oil was released onto the water surface and allowed to strand on the shoreline. In addition to baseline samples, samples were collected immediately after the oil releases, two to three weeks after and one and two years after. Initial observations did not distinguish between effects of the surface and dispersed releases. Total oil content and hydrocarbon compositional analyses were conducted to investigate patterns of uptake and depuration for five different arctic species: Astarte borealis, Macoma calcarea, Mya truncata, Serripes groenlandicus and Strongylocentrotus droebachiensis. Filter-feeding species took up oil rapidly from the water column, while deposit-feeding species took up oil less rapidly from the sediments. All species depurated most of the oil after one year, but after two years the deposit feeders appeared to be taking up more oil from sediments contaminated by stranded oil from the surface oil release.Key words: oil, petroleum, determination, benthos, weathering, degradation, depuration, ArcticMots clés: pétrole, pétroliers, détermination, benthos, dégradation, décomposition, dépuration, arctique

    UVA irradiation of human skin vasodilates arterial vasculature and lowers blood pressure independently of nitric oxide synthase

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    The incidence of hypertension and cardiovascular disease correlates with latitude and rises in winter. The molecular basis for this remains obscure. As nitric oxide (NO) metabolites are abundant in human skin we hypothesised that exposure to UVA may mobilise NO bioactivity into the circulation to exert beneficial cardiovascular effects independently of vitamin D. In 24 healthy volunteers irradiation of the skin with 2 Standard Erythemal Doses of UVA lowered BP, with concomitant decreases in circulating nitrate and rises in nitrite concentrations. Unexpectedly, acute dietary intervention aimed at modulating systemic nitrate availability had no effect on UV-induced hemodynamic changes, indicating that cardiovascular effects were not mediated via direct utilization of circulating nitrate. UVA irradiation of the forearm caused increased blood flow independently of NO-synthase activity, suggesting involvement of pre-formed cutaneous NO stores. Confocal fluorescence microscopy studies of human skin pre-labelled with the NO-imaging probe DAF2-DA revealed that UVA-induced NO release occurs in a NOS-independent, dose-dependent fashion, with the majority of the light-sensitive NO pool in the upper epidermis. Collectively, our data provide mechanistic insights into an important function of the skin in modulating systemic NO bioavailability which may account for the latitudinal and seasonal variations of BP and cardiovascular disease.Journal of Investigative Dermatology accepted article preview online, 20 January 2014

    Information ontrol and the exercise of power in the obstetrical encounter

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    Interactions between doctor and patient involve participants with unequal power and possibly different interests. While a number of studies have focused upon the doctor/patient relationship, few have examined the utility of the concept of power and its capacity to help us understand the outcome of these interactions. The information sought by pregnant women from their obstetricians is used to provide a case study of one conceptualization and test of the utility of the concept of power. Pregnant women and their obstetricians are found to have different perceptions of the information that should be exchanged during their interactions. Women generally fail to obtain the information they want. Lower social class patients desire more and obtain less information than their higher status counterparts

    Entanglement preparation using symmetric multiports

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    We investigate the entanglement produced by a multi-path interferometer that is composed of two symmetric multiports, with phase shifts applied to the output of the first multiport. Particular attention is paid to the case when we have a single photon entering the interferometer. For this situation we derive a simple condition that characterize the types of entanglement that one can generate. We then show how one can use the results from the single photon case to determine what kinds of multi-photon entangled states one can prepare using the interferometer.Comment: 6 pages, 2 figures, accepted for publication in European Journal of Physics

    Entanglement preparation using symmetric multiports

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    We investigate the entanglement produced by a multi-path interferometer that is composed of two symmetric multiports, with phase shifts applied to the output of the first multiport. Particular attention is paid to the case when we have a single photon entering the interferometer. For this situation we derive a simple condition that characterize the types of entanglement that one can generate. We then show how one can use the results from the single photon case to determine what kinds of multi-photon entangled states one can prepare using the interferometer.Comment: 6 pages, 2 figures, accepted for publication in European Journal of Physics

    Simplifying superstring and D-brane actions in AdS(4) x CP(3) superbackground

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    By making an appropriate choice for gauge fixing kappa-symmetry we obtain a relatively simple form of the actions for a D=11 superparticle in AdS(4) x S(7)/Z_k, and for a D0-brane, fundamental string and D2-branes in the AdS(4) x CP(3) superbackground. They can be used to study various problems of string theory and the AdS4/CFT3 correspondence, especially in regions of the theory which are not reachable by the OSp(6|4)/U(3) x SO(1,3) supercoset sigma-model. In particular, we present a simple form of the gauge-fixed superstring action in AdS(4) x CP(3) and briefly discuss issues of its T-dualization.Comment: 1+36 pages, v2,v3 clarifications and references adde

    Sleep quality improvements after MDMA-assisted psychotherapy for the treatment of posttraumatic stress disorder

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    Sleep disturbances (SDs) are among the most distressing and commonly reported symptoms in posttraumatic stress disorder (PTSD). Despite increased attention on sleep in clinical PTSD research, SDs remain difficult to treat. In Phase 2 trials, 3,4-methylenedioxymethamphetamine (MDMA)-assisted psychotherapy has been shown to greatly improve PTSD symptoms. We hypothesized that MDMA-assisted psychotherapy would improve self-reported sleep quality (SQ) in individuals with PTSD and be associated with declining PTSD symptoms. Participants in four studies (n = 63) were randomized to receive 2-3 sessions of active MDMA (75-125 mg; n = 47) or placebo/control MDMA (0-40 mg, n = 16) during all-day psychotherapy sessions. The PSQI was used to assess change in SQ from baseline to the primary endpoint, 1-2 months after the blinded sessions. Additionally, PSQI scores were measured at treatment exit (TE) and 12-month follow-up. Symptoms of PTSD were measured using the CAPS-IV. At the primary endpoint, CAPS-IV total severity scores dropped more after active MDMA than after placebo/control (-34.0 vs. -12.4), p = .003. Participants in the active dose group showed more improvement in SQ compared to those in the control group (PSQI total score Delta M = -3.5 vs. 0.6), p = .003. Compared to baseline, SQ had improved at TE, p < .001, with further significant gains reported at 12-month follow-up (TE to 12-months Delta M = -1.0), p = .030. Data from these randomized controlled double-blind studies provide evidence for the beneficial effects of MDMA-assisted psychotherapy in treating SDs in individuals with PTSD.Stress-related psychiatric disorders across the life spa

    Electric current circuits in astrophysics

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    Cosmic magnetic structures have in common that they are anchored in a dynamo, that an external driver converts kinetic energy into internal magnetic energy, that this magnetic energy is transported as Poynting fl ux across the magnetically dominated structure, and that the magnetic energy is released in the form of particle acceleration, heating, bulk motion, MHD waves, and radiation. The investigation of the electric current system is particularly illuminating as to the course of events and the physics involved. We demonstrate this for the radio pulsar wind, the solar flare, and terrestrial magnetic storms

    Six Years of Chandra Observations of Supernova Remnants

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    We present a review of the first six years of Chandra X-ray Observatory observations of supernova remnants. From the official "first-light" observation of Cassiopeia A that revealed for the first time the compact remnant of the explosion, to the recent million-second spectrally-resolved observation that revealed new details of the stellar composition and dynamics of the original explosion, Chandra observations have provided new insights into the supernova phenomenon. We present an admittedly biased overview of six years of these observations, highlighting new discoveries made possible by Chandra's unique capabilities.Comment: 82 pages, 28 figures, for the book Astrophysics Update
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