5,600 research outputs found

    Study of the distribution of the bronchial tree, the pulmonary artery and the pulmonary vein in the lungs of the sheep

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    1) A description of the early development of the bronchial tree in the sheep is given based on the findings of Nicolas and Dimitrova (1897) and d'Hardiviller (1897) in the sheep, and of Flint (1906) in the pig. In the summary of the findings the nomenclature used in the description of the adult bronchial tree is substituted for that used by these workers. 2) The findings of Flint (1906) on the early development of the pulmonary artery and vein in the pig are recorded, because it is thought that, with certain exceptions, these vessels will follow similar lines of development in the sheep. 3) The external appearance of the lungs is described. The term "pulmonary lobe" is defined, and based on this definition the right lung is divided into four lobes, an apical, a cardiac, an intermediate and a diaphragmatic, and the left lung is divided into two lobes, an apical -cardiac and a diaphragmatic. 4) An analysis is made of the variations which occurred in the external form of the lobes in the lungs of one hundred and fifty sheep, and possible explanations for these variations are suggested. 5) The number of subdivisions of the bronchial tree which occur between a segmental bronchus and a respiratory bronchiole are recorded in the case of three segments. The number of bronchial generations is found to be about sixteen and the number of bronchiolar generations about fifteen. 6) The broncho-pulmonary segments are described following a survey of the lungs of fifteen sheep; the right lung is found to consist of twelve segments and the left lung of eight segments. The basic international nomenclature accepted by the Thoracic Society for the human lung is adopted whenever possible. 7) Following a survey of the lungs of fifty sheep, the main branches of the bronchial tree are described, with attention to the areas which they ventilate. 8) The large branches of the pulmonary arteries are described, following a study of the lungs of fifteen sheep, with reference to the areas of the lung which they supply, and their relations to the bronchi are given. 9) The main tributaries of the pulmonary veins are described with attention to the areas which they drain. They were studied in the lungs of thirteen sheep. 10) A short discussion on the importance of a well defined pulmonary terminology is included

    Water-side turbulence enhancement of ozone deposition to the ocean

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    A parameterization for the deposition velocity of an ocean-reactive atmospheric gas (such as ozone) is developed. The parameterization is based on integration of the turbulent-molecular transport equation (with a chemical source term) in the ocean. It extends previous work that only considered reactions within the oceanic molecular sublayer. The sensitivity of the ocean-side transport to reaction rate and wind forcing is examined. A more complicated case with a much more reactive thin surfactant layer is also considered. The full atmosphere-ocean deposition velocity is obtained by matching boundary conditions at the interface. For an assumed ocean reaction rate of 103 sĀæ1, the enhancement for ozone deposition by oceanic turbulence is found to be up to a factor of three for meteorological data obtained in a recent cruise off the East Coast of the U.S

    Airborne multiwavelength High Spectral Resolution Lidar (HSRL-2) observations during TCAP 2012 : Vertical profiles of optical and microphysical properties of a smoke/urban haze plume over the northeastern coast of the US

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    Ā© Author(s) 2014. This work is distributed under the Creative Commons Attribution 3.0 License.We present measurements acquired by the world's first airborne 3 backscatter (β) + 2 extinction (Ī±) High Spectral Resolution Lidar (HSRL-2). HSRL-2 measures particle backscatter coefficients at 355, 532, and 1064 nm, and particle extinction coefficients at 355 and 532 nm. The instrument has been developed by the NASA Langley Research Center. The instrument was operated during Phase 1 of the Department of Energy (DOE) Two-Column Aerosol Project (TCAP) in July 2012. We observed pollution outflow from the northeastern coast of the US out over the western Atlantic Ocean. Lidar ratios were 50-60 sr at 355 nm and 60-70 sr at 532 nm. Extinction-related ƅngstrƶm exponents were on average 1.2-1.7, indicating comparably small particles. Our novel automated, unsupervised data inversion algorithm retrieved particle effective radii of approximately 0.2 Ī¼m, which is in agreement with the large ƅngstrƶm exponents. We find good agreement with particle size parameters obtained from coincident in situ measurements carried out with the DOE Gulfstream-1 aircraft.Peer reviewedFinal Published versio

    ā€˜O sibling, where art thou?ā€™ ā€“ a review of avian sibling recognition with respect to the mammalian literature

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    Avian literature on sibling recognition is rare compared to that developed by mammalian researchers. We compare avian and mammalian research on sibling recognition to identify why avian work is rare, how approaches differ and what avian and mammalian researchers can learn from each other. Three factors: (1) biological differences between birds and mammals, (2) conceptual biases and (3) practical constraints, appear to influence our current understanding. Avian research focuses on colonial species because sibling recognition is considered adaptive where ā€˜mixing potentialā€™ of dependent young is high; research on a wider range of species, breeding systems and ecological conditions is now needed. Studies of acoustic recognition cues dominate avian literature; other types of cues (e.g. visual, olfactory) deserve further attention. The effect of gender on avian sibling recognition has yet to be investigated; mammalian work shows that gender can have important influences. Most importantly, many researchers assume that birds recognise siblings through ā€˜direct familiarisationā€™ (commonly known as associative learning or familiarity); future experiments should also incorporate tests for ā€˜indirect familiarisationā€™ (commonly known as phenotype matching). If direct familiarisation proves crucial, avian research should investigate how periods of separation influence sibling discrimination. Mammalian researchers typically interpret sibling recognition in broad functional terms (nepotism, optimal outbreeding); some avian researchers more successfully identify specific and testable adaptive explanations, with greater relevance to natural contexts. We end by reporting exciting discoveries from recent studies of avian sibling recognition that inspire further interest in this topic

    Pure hydrogen atmosphere for very cool white dwarfs

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    Microlensing events observed in the line of sight toward the LMC indicate that a significant fraction of the mass of the dark halo of the Galaxy is probably composed of white dwarfs. In addition, white dwarf sequences have now be observed in the HR diagrams of several globular clusters. Because of the unavailability of white dwarf atmospheres for Teff < 4000K, cooling time scales for white dwarfs older than ~ 10 Gyr are very uncertain. Moreover, the identification of a MACHO white dwarf population by direct observation depends on a knowledge of the colors and bolometric corrections of very-cool white dwarfs. In this paper we present the first detailed model atmospheres and spectra of very cool hydrogen white dwarfs for Teff < 4000K. We include the latest description of the opacities of hydrogen and significantly, we introduce a non-ideal equation of state in the atmosphere calculation. We find that due to strong absorption from H_2 in the infrared, very old white dwarfs are brightest in the V, R, and I bands, and we confirm that they become bluer in most color indices as they cool below Teff ~ 3500K.Comment: 6 LaTex pages and 3 postscript figures. To appear in Ap. J. Letter

    An Experimental Platform for Pulsed-Power Driven Magnetic Reconnection

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    We describe a versatile pulsed-power driven platform for magnetic reconnection experiments, based on exploding wire arrays driven in parallel [Suttle, L. G. et al. PRL, 116, 225001]. This platform produces inherently magnetised plasma flows for the duration of the generator current pulse (250 ns), resulting in a long-lasting reconnection layer. The layer exists for long enough to allow evolution of complex processes such as plasmoid formation and movement to be diagnosed by a suite of high spatial and temporal resolution laser-based diagnostics. We can access a wide range of magnetic reconnection regimes by changing the wire material or moving the electrodes inside the wire arrays. We present results with aluminium and carbon wires, in which the parameters of the inflows and the layer which forms are significantly different. By moving the electrodes inside the wire arrays, we change how strongly the inflows are driven. This enables us to study both symmetric reconnection in a range of different regimes, and asymmetric reconnection.Comment: 14 pages, 9 figures. Version revised to include referee's comments. Submitted to Physics of Plasma

    Formation and Structure of a Current Sheet in Pulsed-Power Driven Magnetic Reconnection Experiments

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    We describe magnetic reconnection experiments using a new, pulsed-power driven experimental platform in which the inflows are super-sonic but sub-Alfv\'enic.The intrinsically magnetised plasma flows are long lasting, producing a well-defined reconnection layer that persists over many hydrodynamic time scales.The layer is diagnosed using a suite of high resolution laser based diagnostics which provide measurements of the electron density, reconnecting magnetic field, inflow and outflow velocities and the electron and ion temperatures.Using these measurements we observe a balance between the power flow into and out of the layer, and we find that the heating rates for the electrons and ions are significantly in excess of the classical predictions. The formation of plasmoids is observed in laser interferometry and optical self-emission, and the magnetic O-point structure of these plasmoids is confirmed using magnetic probes.Comment: 14 pages, 12 figures. Accepted for publication in Physics of Plasma

    Psychosocial correlates of attitudes towards male sexual violence in a sample of financial crime, property crime, general violent, and homicide offenders

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    Whilst those currently serving prison sentences for sexual violence can be identified and receive treatment, the number of prisoners with a history of sexual violence against female partners is unknown. Methods to identify prisoners with a proclivity for such violence and accurately assess the risk they pose before and after incarceration are therefore required. Here, we aimed to assess the level of sexually violent attitudes within dating relationships and to examine their associations with experiences of child abuse and neglect (CAN), psychopathic personality traits, prisonization, number of incarcerations, age, years of schooling, relationship status, and parenting among different types of offenders (financial crime, property crime, general violent, and homicide offenders). Data were collected among a large systematically selected sample of adult male inmates (N = 1,123). We demonstrated that sexual violence-supportive attitudes appear to be a function of child sexual abuse, psychopathic personality traits, and may be developed through early socialisation experiences as well as incarceration. Practical implications of current findings are discussed

    Improved Measurement of the Positive Muon Lifetime and Determination of the Fermi Constant

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    The mean life of the positive muon has been measured to a precision of 11 ppm using a low-energy, pulsed muon beam stopped in a ferromagnetic target, which was surrounded by a scintillator detector array. The result, tau_mu = 2.197013(24) us, is in excellent agreement with the previous world average. The new world average tau_mu = 2.197019(21) us determines the Fermi constant G_F = 1.166371(6) x 10^-5 GeV^-2 (5 ppm). Additionally, the precision measurement of the positive muon lifetime is needed to determine the nucleon pseudoscalar coupling g_P.Comment: As published version (PRL, July 2007
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