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
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
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
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 Ć
ngstrƶm 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 Ć
ngstrƶm 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
āO sibling, where art thou?ā ā a review of avian sibling recognition with respect to the mammalian literature
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 āmixing 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 ādirect familiarisationā (commonly known as associative learning or familiarity); future experiments should also incorporate tests for āindirect 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
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
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
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
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
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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