5,557 research outputs found
Zero Temperature Thermodynamics of Asymmetric Fermi Gases at Unitarity
The equation of state of a dilute two-component asymmetric Fermi gas at
unitarity is subject to strong constraints, which affect the spatial density
profiles in atomic traps. These constraints require the existence of at least
one non-trivial partially polarized (asymmetric) phase. We determine the
relation between the structure of the spatial density profiles and the T=0
equation of state, based on the most accurate theoretical predictions
available. We also show how the equation of state can be determined from
experimental observations.Comment: 10 pages and 7 figures. (Minor changes to correspond with published
version.
Vibration effects on heat transfer in cryogenic systems Quarterly progress report no. 1, Jun. 1 - Aug. 31, 1966
Vibration effects on natural convection and fluid transport properties in cryogenic system
HST Imaging of the Globular Clusters in the Fornax Cluster: NGC 1399 and NGC 1404
The Fornax cluster galaxies NGC 1399 and NGC 1404 are ideal for studying the
effects of a cluster environment on globular cluster systems. Here we present
new optical imaging of these two galaxies from both the Hubble Space
Telescope's Wide Field and Planetary Camera 2 and the Cerro Tololo
Inter-American Observatory's 1.5m telescope. The combination of both data sets
provides unique insight on the spatial and colour distribution of globular
clusters. From B-I colours, we find that both galaxies have a broad globular
cluster metallicity distribution that is inconsistent with a single population.
Two Gaussians provide a reasonable representation of the metallicity
distribution in each galaxy. The metal-rich subpopulation is more centrally
concentrated than the metal-poor one. We show that the radial metallicity
gradient can be explained by the changing relative mix of the two globular
cluster subpopulations. We derive globular cluster surface density profiles,
and find that they are flatter (i.e. more extended) than the underlying
starlight. The total number of globular clusters and specific frequency are
calculated to be N = 5700 +/- 500, S_N = 11.5 +/- 1.0 for NGC 1399 and N = 725
+/- 145, S_N = 2.0 +/- 0.5 for NGC 1404. Our results are compared to the
expectations of globular cluster formation scenarios.Comment: 21 pages, Latex, 13 figures, submitted to MNRA
Graptolites from the Benton area of west-central New Brunswick and their regional significance
Graptolites In black slate underlying volcanics along Eel River near Benton, 20 km south of Woodstock, New Brunswick belong to the Clonograptus tenellus Zone of the upper Tremadoc Series. They are essentially the same age as graptolites from the Cookson Formation of southern New Brunswick.
The Belle Lake Slate overlies the same volcanics, and on Belle Brook, 12 km southwest of Benton, contains graptolites referred to the Nemagraptus gracilis Zone of the Caradoc Series. The Belle Lake Slate correlates with an unnamed sequence of greywacke and slate in the Hayesville area of central New Brunswick.
The Ordovician volcanics and overlying sedimentary rocks are the sane general age as a limestone facies found to the east and northeast of Woodstock. The limestones were deposited in shallow-water at varying distances from volcanically active areas.
The presence of lithologlcally similar Lower Ordovician and older rocks in the Benton area of west-central New Brunswick and in the Cookson Formation of southern New Brunswick allows both areas to be included in the same suspect terrane.
RÉSUMÉ
A 20 km au sud de Woodstock (Nouveau-Brunswick) on trouve, dans une ardoise noire recouverte de roches volcaniques, des graptolites qui appartiennent à la zone Clonograptus tenellus de la série du Trémadocien supérieur. Ces graptolites datent essentiellement de la même période que les graptolites de la formation de Cookson du sud du Nouveau-Brunswick.
À 12 km au sud-ouest de Benton, le long du ruisseau Belle, les roches volcanlques mentionnées ci-haut sont recouvertes par l 1 ardoise Belle Lake qui contient des graptolites de la zone à Nemagraptus gracilis de la serle du Caradocien. L‘ardoise Belle Lake est correlée avec une séquence de grauwacke et d'ardoise que l'on retrouve dans la région de Hayesville au centre du Nouveau-Brunswick.
Les roches volcaniques ordoviciennes et les roches sédimentaires qui les recouvrent ont environ le même âge qu'un faciès de calcaire situe à l'est et au nord-est de Woodstock. Les calcaires ont été déposés en eau peu profonde à des distances variables d'une région volcaniquement active.
La présence de roches lithologiquement semblables, certaines datant de l'Ordovicien inférieur, d'autres plus anciennes, dans la région de Benton au centre-ouest du Nouveau-Brunswick et dans la formation de Cookson au sud du Nouveau-Brunswick presuppose une pa renté entre les deux régions.
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Dynamical evolution of globular cluster systems in clusters of galaxies I. The case of NGC 1404 in the Fornax cluster
We investigate, via numerical simulations, the tidal stripping and accretion
of globular clusters (GCs). In particular, we focus on creating models that
simulate the situation for the GC systems of NGC 1404 and NGC 1399 in the
Fornax cluster, which have poor (specific frequency 2) and
rich ( 10) GC systems respectively. We initially assign NGC
1404 in our simulation a typical ( 5) for cluster
ellipticals, and find that its GC system can only be reduced through stripping
to the presently observed value, if its orbit is highly eccentric (with orbital
eccentricity of 0.5) and if the initial scale length of the GCs system is
about twice as large as the effective radius of NGC 1404 itself. These stripped
GCs can be said to have formed a `tidal stream' of intracluster globular
clusters (ICGCs) orbiting the centre of Fornax cluster (many of which would be
assigned to NGC 1399 in an imaging study). The physical properties of these GCs
(e.g., number, radial distribution) depend on the orbit and initial
distribution of GCs in NGC 1404. Our simulations also predict a trend for
to rise with increasing clustercentric distance - a trend for which
there is some observational support in the Fornax cluster.Comment: 12 pages 12 figures, MNRAS in pres
Exercise interventions for maintaining cognitive function in cognitively healthy people in mid life
This is the protocol for a review and there is no abstract. The objectives are as follows: To evaluate the effects ofexercise interventions on cognitive function in cognitively healthy people in mid life. We refer to Forbes 2015b for the review protocol on Exercise interventions for maintaining cognitive function in cognitively healthy people in late life and to Forbes 2015c for the review protocol on Exercise interventions for prevention of dementia in people with mild cognitive impairment
Moyal star product approach to the Bohr-Sommerfeld approximation
The Bohr-Sommerfeld approximation to the eigenvalues of a one-dimensional
quantum Hamiltonian is derived through order (i.e., including the
first correction term beyond the usual result) by means of the Moyal star
product. The Hamiltonian need only have a Weyl transform (or symbol) that is a
power series in , starting with , with a generic fixed point in
phase space. The Hamiltonian is not restricted to the kinetic-plus-potential
form. The method involves transforming the Hamiltonian to a normal form, in
which it becomes a function of the harmonic oscillator Hamiltonian.
Diagrammatic and other techniques with potential applications to other normal
form problems are presented for manipulating higher order terms in the Moyal
series.Comment: 27 pages, no figure
Implications for the origin of dwarf early-type galaxies: a detailed look at the isolated rotating dwarf early-type galaxy CG 611, with ramifications for the Fundamental Plane's (S_K)^2 kinematic scaling and the spin-ellipticity diagram
Selected from a sample of nine, isolated, dwarf early-type galaxies (ETGs)
having the same range of kinematic properties as dwarf ETGs in clusters, we use
CG 611 (LEDA 2108986) to address the Nature versus Nurture debate regarding the
formation of dwarf ETGs. The presence of faint disk structures and rotation
within some cluster dwarf ETGs has often been heralded as evidence that they
were once late-type spiral or dwarf irregular galaxies prior to experiencing a
cluster-induced transformation into an ETG. However, CG 611 also contains
significant stellar rotation (~20 km/s) over its inner half light radius,
R_(e,maj)=0.71 kpc, and its stellar structure and kinematics resemble those of
cluster ETGs. In addition to hosting a faint young nuclear spiral within a
possible intermediate-scale stellar disk, CG 611 has accreted an
intermediate-scale, counter-rotating gas disk. It is therefore apparent that
dwarf ETGs can be built by accretion events, as opposed to disk-stripping
scenarios. We go on to discuss how both dwarf and ordinary ETGs with
intermediate-scale disks, whether under (de)construction or not, are not fully
represented by the kinematic scaling S_0.5=sqrt{ 0.5(V_rot)^2 + sigma^2 }, and
we also introduce a modified spin-ellipticity diagram, lambda(R)-epsilon(R),
with the potential to track galaxies with such disks.Comment: 15 pages (includes 9 figures and an extensive 2+ page reference list
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